Extending BPMN for analysis of human physical risk factors in manufacturing processes

Transcription

1 Eindhoven University of Technology MASTER Extending BPMN for analysis of human physical risk factors in manufacturing processes Polderdijk, M. Award date: 2017 Link to publication Disclaimer This document contains a student thesis (bachelor's or master's), as authored by a student at Eindhoven University of Technology. Student theses are made available in the TU/e repository upon obtaining the required degree. The grade received is not published on the document as presented in the repository. The required complexity or quality of research of student theses may vary by program, and the required minimum study period may vary in duration. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain

2 Department of Information Systems IE&IS Business Process Management Research Group Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes By M. (Melanie) Polderdijk BSc. Technology Management Student identity number In partial fulfillment of the requirements for the degree of Master of Science In Business Information Systems dr. ir. dr. dr. ir. Supervisors: I.T.P. (Irene) Vanderfeesten (TU/e) J. (Jonnro) Erasmus, MSc (TU/e) D. (Dirk) Fahland (TU/e) T. (Tim) Bosch (TNO) J.W. (Gu) Van Rhijn (TNO) Final Version Eindhoven, 24 April 2017

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4 Abstract Within Business Process Management (BPM) process models are used to visualize, analyze and enact processes. A modeling language that is widely used for this is the Business Process Modeling and Notation (BPMN) (Gordijn et al., 2000; Ould, 1995). The notation is originally developed for processes in the administrative domain, but increasingly often BPMN practices are translated to other domains such as manufacturing (Zor et al., 2011) and healthcare (Müller & Rogge-Solti, 2011; Braun et al., 2014). For basic process modeling, this can easily be done as the abstract elements of the notation are widely applicable, but sometimes it is required to model more domain-specific information. For such cases, standard BPMN can be extended with customized elements (Object Management Group, 2011). Currently already many BPMN extensions exist in many different application domains (Braun & Esswein, 2014). A domain in which BPMN is limited in its extensions is that of human factors in manufacturing (Polderdijk, 2016). Still, literature has already indicated that it is important to combine human factors and operational management as the processes of many organizations rely on humans (Neumann & Dul, 2010). Consequently, the aim of this research is to develop an extension for BPMN to enable a human factors risk assessment in a process oriented way for the manufacturing industry. This research has achieved this by using a structured methodology. This methodology includes a well-described design process of the graphical notation and a method to validate it. Until now, BPMN extensions are often designed in an ad hoc manner and their graphical notation is rarely validated. In this research, three conceptual designs are developed and compared to each other based on their cognitive effectiveness and user experience. The cognitive effectiveness is determined by the use of the Physics of Notations theory and the user experience is evaluated by interviewing experts in this field. Combining the results of both evaluations has lead to the final design which is implemented in software. The resulting tool is used to model and analyze processes of two manufacturing companies, particularly Thomas Regout International and Omron. This is done by conducting several interviews. After performing the risk assessment, the interviewees are asked to fill in a survey in order to assess the perceived ease of use, perceived usefulness and intention to use. Based on the results, it is concluded that the BPMN extension is perceived as useful and usable. Additionally, some interesting directions for future research are provided. Keywords: BPMN, human factors, business process management, process modeling, visualization Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes iii

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6 Preface In front of you lies the last report that I will hand in as a student. Five and a half years ago, I started my studies in Groningen and here we are now: 254 kilometers south about to graduate in the master Business Information Systems. During the last six months I have worked on my graduation project in cooperation with the Eindhoven University of Technology and TNO. The result is this master thesis. I am very proud of what I have accomplished during the project, but I certainly could not have done it without the help and support of others. Therefore, I would like to take this opportunity to thank a few people. First of all, I would like to thank Irene Vanderfeesten for being my first supervisor. Your enthusiasm for the subject was very infectious and motivated me to continuously improve my work. I appreciate how you provide positive, but sharp, feedback and you are always willing to help. I am convinced that your guidance in structuring and conducting this project made a great contribution to the final result. So, thank you! I would also like to thank my second and third supervisor, Jonnro Erasmus and Dirk Fahland, and Kostas Traganos. Despite their busy schedules, they have attended my mid-term presentation and reviewed my work which I appreciate very much. Their critical input and feedback helped to improve my thesis even at the very end. Furthermore, I would like to thank Tim Bosch, Gu van Rhijn and Marjolein Douwes for introducing me to the domain of human factors and ergonomics. By sharing their expertise and knowledge, they have helped me to get a better understanding of the application domain of my project. This made me look at it from a totally different perspective. Additionally, I would like to thank the interviewees at Thomas Regout International and Omron for their hospitality and willingness to help me. Their enthusiasm and positive feedback convinced me that my project is valuable in practice as well. Lastly, I would like to thank my family, boyfriend and friends for their support, not only during this project but throughout my whole student life. I have enjoyed it very much and I am looking forward to see what will be next! Melanie Polderdijk March 2017 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes v

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8 Contents Contents List of Figures List of Tables vii ix xi 1 Introduction Thesis Outline Problem Definition & Methodology Problem Statement Research Question Scientific Relevance Research Context Research Scope Stakeholders Physical Risk Factors Methodology Problem Definition Analysis Design Implementation Application Evaluation Theoretical Background Standard BPMN Existing BPMN Extensions Visualization Techniques used for BPMN Extensions Human Factors and Ergonomics Different Types of Human Factors Risks Assessing Human Factors Risks Design Options General Design Decisions Design Options Design I Design II Design III Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes vii

9 CONTENTS 5 Comparative Evaluation & Final Design Comparative Evaluation Theoretical Evaluation: Cognitive Effectiveness Expert Evaluation: User Experience Final Design Implementation 41 7 Application Thomas Regout International Omron Warehouse Process Production Process Assembly Subprocess Evaluation Expert User Acceptance Evaluation: Thomas Regout International Novice User Acceptance Evaluation: Omron Conclusion Contributions Limitations and Future Work Bibliography 57 Appendices 60 A Notation of Standard BPMN B Description of the Tool 63 B.1 Human factors analysis B.2 Additional mechanisms viii Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

10 List of Figures 2.1 The BPM lifecycle Regulative cycle Methodology based on regulative cycle Basic BPMN process model Example elements in BPMN extension for manufacturing Notation of BPMN4People extension Notation of BPMN4CP extension BPMN extension in the domain of ubiquitous processes based on markers BPMN extension in the domain of time based on markers BPMN extension in the domain of risk handling based on new symbols BPMN extension in the domain of costs based on textual annotations BPMN extension in the domain of costs based on colors Categorization of human factors risks Screenshot of Checklist Physical Load: Level 0 questions Screenshot of Checklist Physical Load: Level 1 questions Screenshot of Checklist Physical Load: Evaluation form Design I: Representation of risk level and type Design I: Representation of risk level and type after update Design I: Icon legend Design II: Representation of risk level Design II: Representation of risk types Design II: Representation of risk level after update Design III: Representation of risk level Design III: Representation of risk type Design III: Representation of risk level after update Design III: Representation of risk type after update Visual variables Example of perceptual discriminability calculation Final design Screenshot of the tool: Explanation Screenshot of the tool: Level 0 questions of human factors analysis Screenshot of the tool: Report generator End to end process model of TRI Process model of PL2.1 Manual loading of TRI Process model of PL2.3 Manual unloading of TRI Process model of warehouse process of Omron Process model of production process of Omron Process model of assembly subprocess of Omron Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes ix

11 LIST OF FIGURES A.1 BPMN 2.0 Notation B.1 Screenshot of the tool: Empty template B.2 Screenshot of the tool: Process model before human factors analysis B.3 Screenshot of the tool: Level 0 questions of human factors analysis B.4 Screenshot of the tool: Level 1 questions of human factors analysis B.5 Screenshot of the tool: Process model after human factors analysis B.6 Screenshot of the tool: Process model after human factors analysis B.7 Screenshot of the tool: On/off-switch of BPMN extension B.8 Screenshot of the tool: Report generator x Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

12 List of Tables 2.1 Physical risk factors Extended classification framework of BPMN extensions Advantages and disadvantages of visualization techniques Levels of questionnaire (TNO) Design options Summary of conceptual designs Principles of the Physics of Notations theory Visual variables used in conceptual designs to express specific information Semiotic clarity scores for conceptual designs Perceptual discriminability scores for conceptual designs Visual expressiveness scores for conceptual designs Semantic transparency scores for conceptual designs Complexity management scores for conceptual designs Cognitive integration scores for conceptual designs Dual coding scores for conceptual designs Graphic economy scores for conceptual designs Cognitive fit scores for conceptual designs Evaluation of conceptual designs with Physics of Notations theory Evaluation of conceptual designs by user experience experts User acceptance results Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes xi

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14 Chapter 1 Introduction Every organization has to manage its business processes in order to deliver a product or service to its customers (Dumas et al., 2013). The set of activities regarding the management of business processes can be captured in the term Business Process Management (BPM). Business Process Management is the art and science of overseeing how work is performed in an organization to ensure consistent outcomes and to take advantage of improvement opportunities. (Dumas et al., 2013) A core aspect in BPM is process modeling (Van Der Aalst, 2013). Process models visualize how a particular business case should be handled and can be used to describe, analyze and enact a process (Gordijn et al., 2000; Ould, 1995). A modeled business process can, for instance, be analyzed using simulation to estimate Key Performance Indicators (KPI s) such as costs or cycle time (Van Der Aalst, 2013). Based on the results of these analyses, management can come up with new ideas on how to improve the process. There are many types of process models, each having its own modeling language. A process modeling language that is widely adopted as standard is the Business Process Modeling and Notation (BPMN) from the Object Management Group (OMG) (Chinosi & Trombetta, 2012). The aim of BPMN is to visualize business processes in a way for both technicians and nontechnicians to understand. The origin of BPM and process modeling lies in the administrative domain. Therefore, BPMN is usually applied to model business and administrative processes (Chinosi & Trombetta, 2012). However, increasingly often BPMN practices are translated to other domains such as manufacturing (Zor et al., 2011) and healthcare (Müller & Rogge-Solti, 2011; Braun et al., 2014). For basic modeling, this can easily be done since the abstract elements of the notation are widely applicable. However, sometimes it is required to model more domainspecific information. In such cases, standard BPMN might not be able to capture the right amount of detail. To overcome this, BPMN can be extended with customized elements (Object Management Group, 2011). Currently already many extensions exists in multiple application domains (Braun & Esswein, 2014). Still, very few of these extensions focus on the manufacturing domain (Polderdijk, 2016). Only Zor et al. (2011) have proposed a customized notation to represent explicit manufacturing-specific constructs such as assembly and material routes. However, there are many more domain-specific issues that play part in managing these kind of processes. One of them is the well-being of workers involved in the manufacturing activities. In both decision-making processes and operations, employees play an important role. The well-being of an operator can have a big influence on the throughput time or quality of a product (Kahya, 2007). Moreover, a company should take the responsibility in keeping its employees healthy anyway. Therefore, it is an important aspect to include in process analysis and the reason why this research focuses on this subject. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 1

15 CHAPTER 1. INTRODUCTION The issues related to the well-being of workers can be captured in the term human factors and ergonomics. A definition that is often cited is that of the International Ergonomics Association (IEA): Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance. (IEA, 2016) Within the manufacturing industry, the occurrence of health related problems are present in all kinds of forms. Physical loads at a workplace, such as lifting and carrying too heavy objects or using vibrating tools for too long, are the most dominant causes of musculoskeletal disorders. However, one can also think of the mental workload of workers that have to perform a simple task over and over again for hours. These issues can reduce their well-being and may lead stressrelated disorders. Within the discipline of human factors, it is aimed to identify these kind of risks and design solutions to reduce them (Stanton et al., 2004). It is already proven that applying human factors practices in the design of operational systems can not only improve the well-being of workers, but also system performance (Neumann & Dul, 2010). Especially when these practices are applied in early design stages, costs of potential changes to the process can be reduced and productivity can be affected (Paquet & Lin, 2003; Neumann et al., 2006). Since the application of human factors can influence business processes that much, it is a very important area to include in BPM. Therefore, it is surprising that little research has been done on combining human factors and the standard modeling language used for BPM. Similarly as the KPI s mentioned before, human factors risks are important to analyze in the management and optimization of processes. Consequently: Research Objective The aim of this research is to develop an extension for BPMN to enable a human factors risk assessment in a process oriented way for the manufacturing industry. 1.1 Thesis Outline The remainder of this thesis is organized as follows. Chapter 2 describes the problem definition and methodology. Here, the problem statement, research questions and scope are explained as well. The theoretical background for this research is discussed in Chapter 3. In this chapter, a comparison of existing BPMN extensions and their graphical notations is made by the use of a framework. Moreover, it describes the domain of human factors and explains a categorization of risk factors used within this domain. Chapter 4 covers the design of the BPMN extension. This chapter discusses the design process and presents three conceptual designs. The comparison of these three design options and choices leading to the final design are discussed in Chapter 5. In Chapter 6, it is described how the final design is implemented in a tool and Chapter 7 discusses the application of this tool. Here, it is explained how the tool is used to model and analyze the processes of two manufacturing companies in practice. Based on the application, an evaluation is performed of which the results are summarized in Chapter 8. Finally, the conclusions of the project are provided in Chapter 9. Moreover, this chapter contains a discussion in which the limitations and directions for future research are discussed. 2 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

16 Chapter 2 Problem Definition & Methodology As mentioned in the introduction in Chapter 1, the aim of this research is to develop a BPMN extension to enable a human factors risk assessment in a process oriented way for the manufacturing industry. By enabling this risk analysis, the BPMN extension can be used in managing processes. The management of processes is often placed in a framework called the BPM lifecycle (Dumas et al., 2013). This is a step-by-step method that describes the phases from identifying a problem, designing a suitable solution and implementing this solution. It is presented in Figure 2.1. Figure 2.1: The BPM lifecycle (Dumas et al., 2013) Dumas et al. (2013) describe the phases in the figure as follows: 1. Process Identification: a business problem is identified. In this phase, an overview of all the processes related to this problem and the links between these processes is created. 2. Process Discovery: a process model is made of the current state. 3. Process Analysis: a structured overview of the issues related to the current state of the problem domain is made. This overview typically prioritizes these issues based on their impact and, when possible, quantifies them using performance measures. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 3

17 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY 4. Process Redesign: a process model is made of the to-be situation. In this phase, multiple options to improve the process are proposed, evaluated and combined in order to solve the problem. 5. Process Implementation: the required changes to go from the as-is to the to-be situation are prepared and performed. 6. Process Monitoring and Controlling: data is gathered and analyzed. Based on these data, it is determined whether the to-be situation satisfies the performance measures and objectives. As can be seen in Figure 2.1, this research focuses on the application of process models in the Process Analysis and Process Redesign phase. The BPMN extension that is developed allows for an analysis of human factors risks which is meant to be performed during the Process Analysis phase. Based on the results of this analysis, suitable redesign options can be developed in the Process Redesign phase. The remainder of this chapter builds upon the research aim by defining the problem and context in more detail. Section 2.1, Section 2.2 and Section 2.3 describe the problem statement, research questions and scientific relevance respectively. In Section 2.4, the research context is described and the scope is set in Section 2.5. Finally, the methodology for conducting the research is explained in Section Problem Statement Currently many BPMN extensions exist in many different domains (Braun & Esswein, 2014; Polderdijk, 2016). However, none of them is representing information on human factors yet even though literature states that combining human factors and operational management can improve both workers well-being and system performance (Neumann & Dul, 2010; Neumann et al., 2006). Furthermore, the existing BPMN extensions are often developed in an ad hoc manner and are not validated well (Polderdijk, 2016). Sometimes example processes are used to illustrate the use of extended BPMN, but the graphical notation is rarely evaluated. Still, literature proves that the quality of process models can be assessed and that evaluation of notation is possible (Genon et al., 2010; Mendling, 2012; La Rosa et al., 2011; Maes & Poels, 2007; Claes et al., 2015). For instance, Genon et al. (2010) have already used the Physics of Notations theory to evaluate the cognitive effectiveness of standard BPMN 2.0. Together these findings lead to the following problem statement: Problem Statement Standard BPMN and its current extensions lack in their capability of describing information on human factors and, with that, do not support analysis of human factors risks for processes in the manufacturing domain. Moreover, current BPMN extensions are developed in an ad hoc manner and their graphical notations are often not validated. Consequently, this research focuses on extending BPMN with more information on risks related to human factors in a structured way and with a particular focus on the validation of the graphical notation of this extension. 4 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

18 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY 2.2 Research Question Based on the problem statement and research objective, a research question is set. Research Question How can risks regarding human factors be visualized in the modeling language BPMN such that it is usable for process analysis? By answering this question, this research aims to fill in the gaps mentioned in the problem statement and with that generate knowledge in a fairly new research domain, particularly that of human factors and BPM. In Section 2.6, the research question is split up into subquestions and it is discussed how these subquestions are answered. 2.3 Scientific Relevance This research contributes to the existing literature in three ways. Primarily, it develops a BPMN extension in a yet uncovered application domain, particularly that of human factors in manufacturing processes. On top of that, it aims to do this by the use of a structured approach while previous extensions are often developed in an ad hoc manner. Lastly, this research shall have a particular focus on validating the graphical notation of the BPMN extension. So far, little attention is paid to this subject. 2.4 Research Context The BPMN extension in this research is created with the help of human factors and ergonomics experts from TNO. TNO is a company that aims to create sustainable innovations by connecting people and knowledge ( They have developed several methods to assess risk factors for the development of work related disorders. One might think of methods to assess the physical risk caused by prolonged standing or the organizational risk caused by too little autonomy. The knowledge and experience of TNO in this field is used to develop the BPMN extension. This research is also related to the HORSE project in which both the Eindhoven University of Technology (TU/e) and TNO participate. The HORSE project is an European Research Project that aims to innovate the manufacturing industry by introducing a new flexible model for smart factories ( The model should realize industrial tasks more efficiently by involving the collaboration of humans, robots, Autonomous Guided Vehicles (AGVs) and machinery. The aim of the TU/e within the HORSE project is to include BPM practices into the smart model. TNO participates as being experts in the domain of human factors and ergonomics. This research relates to the HORSE project by combining information on human physical risks and BPM. It aims to visualize the results of a risk assessment tool of TNO within BPMN such that it makes it easier for business users to see where employees might get problems. These insights can be useful in, for instance, determining the potential value of the application of robots. 2.5 Research Scope The domain of human factors, as well as that of BPM, is very broad. Many aspects play part in the design and application of a BPMN extension in the domain of human factors. In order for the research to be conducted in a structured way while delivering useful results within the given Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 5

19 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY time constraints, a scope is determined. stakeholders and the human factors risks. This section describes the scope on two aspects: the Stakeholders As mentioned at the beginning of this chapter, the BPMN extension that is developed in this research can be used within the Process Analysis and Process Redesign phase of the BPM lifecycle. The BPM practices within this lifecycle involve multiple, varying stakeholders. Dumas et al. (2013) describe the following: The Management Team: has the overview of all processes, needs to initiate process redesign activities and provides resources and strategic guidance to the other stakeholders involved. Process Owners: are responsible for the efficiency and effectiveness of a certain process. Process Participants: perform the day-to-day activities related to a process. Process Analysts: perform the process identification, discovery, analysis and redesign phases and coordinate the implementation and monitoring phases. System Engineers: translate redesign requirements into IT system design. The BPM Group: is responsible for preserving a BPM culture and ensuring that this culture supports the strategic goals of the organization. Each stakeholder has its own responsibilities within the lifecycle and consequently, they all need different input to perform their tasks. Moreover, they are likely to use different methods and tools as well. As each stakeholder has his own requirements for the information he receives, it would not be logical to use the same process model containing the same information for all stakeholders. With respect to the BPMN extension in the domain of human factors, this could imply that multiple views should be developed for the different stakeholders. For instance, a Process Analyst in the domain of human factors would likely prefer to see the results of the risk assessment in more detail than the Management Team. Since time constraints make it impossible to develop customized views for all stakeholders, it is decided to design the BPMN extension based on the requirements of one stakeholder only. Since the scope of this research are the Process Analysis and Redesign phases of the BPM lifecycle, it is chosen to focus on the Process Owner. This stakeholder is involved in almost every phase, from process modeling to process monitoring (Dumas et al., 2013). In the Process Discovery phase, the Process Owner serves as a domain expert that knows how the activities in the process are performed. With his knowledge he can help the Process Analyst in modeling the process. Typically, the Process Owner needs to approve the process models at the end. In the next phase, the Process Analysis, the Process Owner should provide the Process Analyst with the required information related to the problem. This includes qualitative as well as quantitative information. During Process Redesign and Implementation, the Process Owner should give feedback and make the final decisions. Finally, when the redesigned process is running in the Process Monitoring and Controlling phase, the Process Owner can use the data from the BPM system to draw conclusions on, for instance, the performance or conformance of a process. Besides that the Process Owner is involved in multiple stages of the BPM lifecycle, there is another reason for focusing on this stakeholder. This reason is that the Process Owner has the most general requirements regarding the amount of detail of the BPMN extension. The Process Owner does not require such specific information as the Process Analyst or System Engineer, but the view preferred by the Management Team would probably be too abstract. Therefore, it is assumed that a design based on the view of the Process Owner is a good base for the BPMN extension in the domain of human factors. In the future, this view could be extended or made more abstract to fit better to the requirements of the other stakeholders as well. 6 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

20 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY Physical Risk Factors TNO divides occupational human factors risks into five categories: Physical, Organizational, Dangerous substances, Environmental and Safety ( Even though every category is important to assess, it is decided to only focus on the physical risk factors for this research due to time constraints. Focusing on one category limits the amount of risk factors for which a representation needs to be designed and leaves out issues on combinations of different categories of factors. The reason to focus on the physical risk factors is that the risks of these are relatively straight-forward to determine. The majority of the questions used to assess this type of risk can be answered by either yes or no which simplifies the calculation of the actual risk level. On top of that, it is a very relevant factor for the manufacturing domain as these type of processes often require physical effort. The category of physical risk factors consists of multiple risk factors. Table 2.1 shows the physical factors that are considered in this research, together with a short description. More on the categories of risk factors and how to assess them is discussed in Section 3.3. Table 2.1: Physical risk factors (TNO, 2012) Physical risk factor Lifting and carrying Pushing and pulling Hand-arm tasks Working postures Computer-related work Vibration Energetic over load Energetic under load Description The intensity of workers lifting and carrying objects The intensity of workers rolling, sliding, pushing or pulling objects in different ways Duration and type of tasks workers perform by using their hands and/or arms Duration of different types of working postures Duration of work that requires a computer or laptop Intensity and duration of contact between workers and vibrating objects The energy a worker has to deliver beyond his limits The duration of sitting 2.6 Methodology To answer the research question, a design science research is performed. The methodology for doing this is based on the regulative cycle of Van Strien (1997) which consists of five phases. As can be seen in Figure 2.2, this research evaluates the design by applying it in practice. The regulative cycle is an iterative approach which means that after evaluation is done, a new problem can be identified and tackled with the same steps as the previous one. So, after a cycle is completed there is a validated solution that can be used on its own, but it can also be improved in a following cycle. For this research this implies that after completing all steps the BPMN extension is validated, but it can also be extended or improved in future research. Figure 2.2: Regulative cycle of Van Strien (1997) Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 7

21 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY To provide more insight in the exact steps of this research, Figure 2.3 contains a more detailed representation of the methodology. The first two phases of this methodology are similar to that of the original regulative cycle. However, the Design phase is split into three parallel steps and an additional evaluation is added to decide upon the final design. Furthermore, the Application and Evaluation phase are split into two parallel steps since the implemented design is tested in two manufacturing companies. In the following sections, each of the phases is explained in more detail and the research subquestions are given. Figure 2.3: Methodology based on regulative cycle of Van Strien (1997) 8 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

22 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY Problem Definition In the Project Definition phase, the problem addressed in the research and the context of the problem are described. As this research aims to develop a BPMN extension in the domain of human factors, the current situation of this subject is analyzed by reviewing literature and interviewing human factors experts of TNO. Based on the findings, the problem statement and research questions are formulated. The result of this phase is the problem description in this chapter. It provides the motives and directions of the research. Moreover, it describes the methodology of the research Analysis In the Analysis phase, literature is reviewed and interviews are conducted to gain more insight in the research area: BPMN and human factors. This phase can be divided in two parts, each having its own subquestion. The first subquestion aims to provide insights in how new information can be visualized in BPMN. The second subquestion addresses what information should be visualized in a BPMN extension in the domain of human factors in manufacturing. Q1: Which visualization techniques are used in existing BPMN extensions? Q1.1: Which BPMN extensions do currently exist in the manufacturing domain? Q1.2: How do existing BPMN extensions visualize new information belonging to the extension? Q1.3: What are the advantages and disadvantages of the visualization techniques used in existing BPMN extensions? The first subquestion addresses the existing BPMN extensions. As is stated in the problem definition, not many of the existing BPMN extensions focus on the manufacturing domain (Braun & Esswein, 2014; Polderdijk, 2016). However, these few extensions are worth analyzing as they provide insight in the application domain of the to-be designed BPMN extension. By conducting a literature review, it is determined what subjects are already covered by existing BPMN extension in the manufacturing domain. Since the number of BPMN extensions in the manufacturing domain is very low, it is decided to broaden the scope in analyzing the visualization techniques that are used. The visualization techniques of BPMN extensions from multiple application domains are analyzed as these can provide provide useful insights in how certain concepts can be visualized. This was already done in the literature review of Polderdijk (2016) which was conducted in preparation of this research. It extends the framework of Braun & Esswein (2014) and compares the graphical notations of some existing BPMN extensions. Furthermore, it mentions the advantages and disadvantages of the different visualization techniques. By describing these subjects, the literature review provides the answer to the first subquestion and is therefore summarized in Chapter 3. Q2: What concepts should be included in a BPMN extension on physical risk factors to support process analysis? Q2.1: What does the human factors domain entail? Q2.2: How can a process be analyzed on physical risk factors? The aim of the second subquestion is to gain more information on the application domain of the to-be designed BPMN extension. It is answered by both reviewing literature and interviewing the human factors experts of TNO. The human factors domain in general is analyzed and it is researched how physical risk factors can be assessed. A method TNO has developed to evaluate physical risk factors is addressed. This method forms the base of the risk assessment enabled by the BPMN extension. The results of this part are described in Chapter 3 as well. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 9

23 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY Design In the third phase of the project, the information of the analysis phase is used to create three different design options for the BPMN extension in the domain of human factors. The advantages and disadvantages of visualization techniques are used to make well-founded decisions on how to visualize the concepts necessary for a physical risk factors assessment. This provides the answer to the third subquestion. Q3: How can a BPMN extension be designed such that it supports a process oriented analysis of physical risk factors? Where the regulative cycle of Van Strien (1997) incorporates only one design, this research methodology splits up this phase into three. Three designs are developed based on the requirements of a Process Owner regarding human factors. These are reviewed by the human factors experts from TNO where after they are updated. The design decisions and different design options resulting from this phase are described in Chapter 4. Comparative Evaluation During the comparative evaluation, the three designs are evaluated in comparison to each other in two ways. The Physics of Notations theory is used to assess the cognitive effectiveness of the designs and interviews are conducted with experts to determine the quality in terms of user experience. Based on the results, a final design is selected and, with that, the fourth subquestion is answered. Q4: Which of the design options is best? Q4.1: Which design option has the highest cognitive effectiveness based on the Physics of Notations theory? Q4.2: Which design option has best user experience according to experts? To decide upon the design with the highest cognitive effectiveness, they are ranked based on the principles of the Physics of Notations theory. For each of the nine principles of this theory, scores are assigned to the designs based on how well they satisfy the principle. By adding the scores, it is determined which design has the highest cognitive effectiveness. In the expert evaluation, interviews are conducted with user experience experts. Their feedback is summarized in some general quotes on the user experience of the design. Based on this overview and the scores on the cognitive effectiveness, it is decided which design is best. This final design and the prior comparative evaluation are described in Chapter Implementation The result of the comparative evaluation, particularly the final design, is implemented in a tool. This tool enables a physical risk factors analysis in a process oriented way by integrating the risk assessment method from TNO with BPMN. In doing so, it provides an answer to the fifth subquestion. Q5: How can the final design be implemented such that it supports a process oriented analysis of physical risk factors? A description of the implementation of the BPMN extension is provided in Chapter Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

24 CHAPTER 2. PROBLEM DEFINITION & METHODOLOGY Application The tool resulting from implementing the BPMN extension is used to perform a physical risk factors assessment in practice. Interviews are held with Process Owners from two manufacturing companies. In these interviews, their processes are modeled and analyzed in order to answer the sixth subquestion. Q6: How can the tool be applied in practice to perform a process oriented analysis of physical risk factors? The result of this phase are process models in which the results of a physical risk factors assessment are visualized by the use of the BPMN extension. These models are used in evaluating the extension in the Evaluation phase. The application of the tool is described in Chapter 7. Here, the process models made with the BPMN extension for the two manufacturing companies are presented and discussed Evaluation The visualization of the process models and the application of the tool in practice is evaluated in the Evaluation phase. By using the Method Evaluation Model from Moody (2003) and semistructured interviews, it is determined whether the extension is perceived as useful and usable for a process oriented human factors risk assessment. By that, this Evaluation phase provides the answers to the seventh and eight subquestions. Q7: Is the BPMN extension useful for the activities of a Process Owner related to analyzing physical risk factors? Q8: Is the BPMN extension usable for the activities of a Process Owner related to analyzing physical risk factors? Chapter 8 summarizes the evaluation with the Process Owners on the perceived usefulness and usability. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 11

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26 Chapter 3 Theoretical Background This chapter describes the theoretical background and provides answers to the two subquestions of the analysis phase of this research. First, some background is given on the standard notation of BPMN in Section 3.1. Secondly, Section 3.2 explains what has already been done in extending BPMN for the manufacturing domain. Here, information is given on the visualization techniques that are generally used in BPMN extensions. In Section 3.3, the domain of human factors in manufacturing is described. This section explains the different categories of human factors risks and the method TNO uses to assess the level of risk of physical risk factors. 3.1 Standard BPMN Before jumping into the existing BPMN extensions, it is necessary to have some background on the notation of standard BPMN. The simple process model in Figure 3.1 illustrates the basic elements of standard BPMN. As can be seen, each shape corresponds to a certain concept. For instance, activities are presented as boxes and events are presented as circles. All elements are connected by arrows. These arrows represent the flow of business cases. The gateways, characterized by diamond shapes, represent decision points or parallel splits. They can be seen as routing elements, because they determine whether only one path can be taken, i.e. decision point, or both paths should be taken, i.e. parallel split. A third option is for a gateway to allow one or multiple paths to be taken. The symbol inside the gateway element determines the type. In case of Figure 3.1, the cross defines that this gateway is a decision point. The complete notation of standard BPMN 2.0 is presented in Appendix A. Figure 3.1: Basic BPMN process model 3.2 Existing BPMN Extensions The abstract elements of standard BPMN are not always able to capture the right amount of detail. Therefore, prior research and attempts have been done on extending BPMN for a specific domain or purpose. However, not many of the existing BPMN extensions are developed for the manufacturing domain, which is the focus of the research. An exception is the extension proposed Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 13

27 CHAPTER 3. THEORETICAL BACKGROUND by Zor et al. (2011). In general, BPMN is used to model paper processes at a business level, but the aim of their proposed extension is to model the processes on the shop floor as well. In their notation, they have adjusted some basic elements of BPMN to make it possible to model manufacturing-specific constructs. For instance, the gateway element is customized to represent the concept of assembly as is shown in Figure 3.2. (a) Split material (b) Join material Figure 3.2: Example elements in BPMN extension for manufacturing (Zor et al., 2011) Even though standard BPMN and other extensions could be applied to model manufacturing processes, the extension of Zor et al. (2011) is the only one that specifically focuses on this domain. For instance, extensions aiming to combine BPMN and costs could be used for manufacturing processes as well, but the base of these extensions is standard BPMN and its original application domain (Magnani & Montesi, 2007; Lodhi et al., 2011). The processes used in developing and demonstrating these extensions are usually high-level business processes. So, applying the extension directly to manufacturing processes might not always be possible or optimal. Hence, it can be concluded that the number of BPMN extensions focusing on the manufacturing domain is limited. To still gain more insights in the graphical notations of existing BPMN extensions, it is therefore decided to look beyond the extensions for manufacturing. This is done based on the classification framework of Braun & Esswein (2014). Based on their framework, they have concluded that the majority of the papers on BPMN extensions is published as a research report or in conference proceedings. This implies that the research on BPMN extensions has a lack of maturity. Furthermore, most extensions are developed in an ad hoc manner and more than half of the extensions does not provide the definition of new graphical elements explicitly. To provide more insights in the visualization techniques that are used in existing BPMN extensions, the literature review of Polderdijk (2016) extends the framework of Braun & Esswein (2014) with four aspects. These are: 1. The sub-application domain 2. The information that is added 3. The basic BPMN elements that are adjusted 4. The visualization technique used A summary of all the BPMN extensions described in the literature review and their characteristics regarding the four additional aspects is presented in Table 3.1. To demonstrate this framework, let us look at two examples of BPMN extensions. First of all, Figure 3.3 shows the notation of the BPMN4People extension from Brambilla et al. (2012) which is the first row of Table 3.1. BPMN4People is a specific notation for expressing social media interactions within process models. This extension was classified within the domain of Social BPM by the framework of Braun & Esswein (2014), but as the term Social BPM is quite broad and covers all kinds of social networking applications, the (detailed) domain according to Polderdijk (2016) is social media. The new information that this extension can visualize are social media interactions which is done by icons on top of activity elements. These small icons that can be added to basic BPMN elements are called markers. That is why the visualization technique of this extension is classified as markers. 14 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

28 CHAPTER 3. THEORETICAL BACKGROUND Figure 3.3: Notation of the BPMN4People extension (Brambilla et al., 2012) Another example of an extension is the BPMN4CP from Braun et al. (2014). It is mentioned in the second row of Table 3.1. BPMN4CP is an extension to model clinical pathways. The overall domain, classified by Braun & Esswein (2014), is e-health. However, it specifically focuses on care pathways which is why the framework of Polderdijk (2016) specifies this as the (detailed) domain. The extension adds new information on hospital activities, levels of evidence and patient files. Similar to the BPMN4People extension, this extension uses markers to express the new information as is shown in Figure 3.4. However, the markers are not only placed on the activity elements but also on data objects and gateways. On top of that, different colors are used to represent different levels of evidence. Figure 3.4: Notation of the BPMN4CP extension (Braun et al., 2014) Similarly as for the BPMN4People and BPMN4CP extensions, these four columns were filled in for all the 19 extensions in Table 3.1. From the resulting framework, it can be concluded that the application domains of the extensions are very diverse. However, it is notable that most of the application domains are about the information on business processes and requirements for the manager or end-users of the process. Less attention is spend on the resources that are actually performing the tasks. The extension of Wolter & Schaad (2007) covers some aspects on resources, particularly those of authorization constraints, but these do not include information on the employees themselves. This is remarkable as resources play an important role in both decision-making processes and operations. As already mentioned in Chapter 1, their well-being can have a great influence on the performance of a task (Neumann & Dul, 2010) and is therefore valuable to analyze and monitor. Regarding the visual notation, no clear pattern can be found. Multiple BPMN elements are customized by the use of all kinds of visualization techniques. No technique or combination seems to stand out. However, each visualization technique has its own advantages and disadvantages. These are discussed in the next subsection. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 15

29 CHAPTER 3. THEORETICAL BACKGROUND Table 3.1: Extended classification framework of BPMN extensions (Polderdijk, 2016) Authors Year Domain (Detailed) Domain New information Extended Elements Brambilla et al Social BPM Social media Social media interactions Braun et al E-Health E-Health (Care pathways) Fernandez et al Usability Business domain expert simplification Friedenstab et al Performance measurement Business activity monitoring Hospital activities, levels of evidence, patient files Activities Markers Activities, Data, Gateways None Activities, Events, Data, Gateways Visualization technique Markers, Color Symbols Duration, frequency Artifacts Symbols, Text Gagne & Trudel 2009 Time Time Time constraints Activities Markers Costs (Areas) Costs Swimlanes, Activities Color Lodhi et al Performance measurement Magnani & Montesi 2007 Performance measurement Costs (Concrete) Costs Artifacts, Sequence flows Magnani & Montesi 2009 Artifacts Data representation Data Data, Artifacts Symbols Marcinkowski & Kuciapski 2012 Risk management Risk handling Risks, risk handling Activities, Artifacts Symbols, Text options Momotko et al Process execution Distributed process execution Müller-Wickop & Schultz 2013 Compliance and Audits Rodriguez et al Risk management Process security requirements Saeedi et al Quality management Service quality requirements Saleem & Hassan 2012 Risk management Software security requirements Sungur et al Sensors Wireless sensor networks Supulniece et al Knowledge Knowledge representation Wolter & Schaad 2007 Authorization Task-based authorization Yousfi et al Ubiquitous processes Ubiquitous business processes Timing, criticality, process instances and participants Financial Accounting Money, transactions, bank accounts Text Activities Markers, Color, Text Activities, Events Text, Color Security requirements Artifacts Symbols Time, costs, reliability Activities Markers, Text Security requirements Sequence flows Symbols Wireless sensor interaction Knowledge, information, data Authorization constraints Smart object interactions Zor et al Manufacutring Manufacturing Routing information, tool and raw material inventory, manufacturing tasks Activities Markers Activities, Artifacts Text Artifacts Text Activities, Data Markers Activities, Gateways, Sequence flows, Artifacts Markers 16 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

30 CHAPTER 3. THEORETICAL BACKGROUND Visualization Techniques used for BPMN Extensions When analyzing the existing extensions, several visualization techniques can be distinguished. First of all, markers can be used to extend the language. Markers are small icons that can be added to basic BPMN elements to express that a certain element is of a specific type. An example of an extension that introduces markers is that of Yousfi et al. (2016), presented in Figure 3.5. In this extension, activities and data objects can be adapted with small figures representing sensors, readers, images and more. Figure 3.5: BPMN extension in the domain of ubiquitous processes based on markers et al., 2016) (Yousfi The advantage of markers is that standard BPMN elements are mostly preserved. Consequently, the extended constructs are relatively easy to understand once one understands the syntax of standard BPMN. Often markers are presented as real world objects that are related to the concept they are expressing. The use of familiar objects from the real world makes a modeling language intuitive to its users (Fernández et al., 2010). Besides the shape of a marker, also its location can be used to express certain concepts. For instance, in time-bpmn, the location of the marker tells whether a constraint concerns the start or end of the activity (Gagne & Trudel, 2009). Figure 3.6 demonstrates this mechanism. An activity with the marker on the left side defines that the activity should start as soon as possible. A marker on the right side defines that the activity should finish as soon as possible. Figure 3.6: BPMN extension in the domain of time based on markers (Gagne & Trudel, 2009) Another way of extending BPMN is by introducing new symbols. Sometimes standard BPMN elements do not have the capability to express the required concepts for the extension. In such cases, developing a new artifact might be a solution. An example of an extension that introduces new symbols is the risk handling extension of Marcinkowski & Kuciapski (2012), presented in Figure 3.7. Besides the marker of a warning sign on the activity element, this extension also uses the warning sign as a new artifact associated to the arrows. The advantage of designing an extension with this visualization technique is that the development of new elements is more flexible, since it is not restricted to the characteristics of an already existing one. However, one should always ensure that the syntax of standard BPMN elements is preserved when additional elements are included. A disadvantage of introducing new elements is that new constructs are not necessarily understood right away and users might need time to fully learn how to use the extended language. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 17

31 CHAPTER 3. THEORETICAL BACKGROUND Figure 3.7: BPMN extension in the domain of risk handling based on new symbols (Marcinkowski & Kuciapski, 2012) Some extensions use textual notations to express certain concepts. Even though texts can capture very specific and concrete information, it can also make a model quite complex and unreadable. Moreover, including too much information by the use of text also contradicts with the reason why BPMN is developed in the first place, namely to visualize business processes to create an overview (Dumas et al., 2013). It is therefore notable that the extensions based on textual notations often include only few, and often numerical, values. An example of an BPMN extension that uses textual notations is the costs extension of Magnani & Montesi (2007). As can be seen in Figure 3.8, the textual annotations that are used are numerical. Figure 3.8: BPMN extension in the domain of costs based on textual annotations Montesi, 2007) (Magnani & Finally, colors can be used to represent new concepts. Colors are very effective since the human visual system is very sensitive to variations in color (Genon et al., 2010). They can cause objects to stand out and draw the attention to themselves (Winn, 1993). Still, there are some disadvantages of using color as the only visual variable to describe a concept in BPMN. The most important deficiency is that it limits the ability of making fast and simple sketches of process models by hand. Yet, such sketches are regularly used to improve communication about processes in practice. When only color is used, one should have different colors of pencils on hand to express the necessary information which is rarely the case. Another consequence of using just color to display information is that it becomes impossible for color blind people to read the model (Ware, 2012). The BPMN extension of Lodhi et al. (2011) is an example of an extension that uses color. Figure 3.9 shows how this extension represents costs levels by different colors. 18 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

32 CHAPTER 3. THEORETICAL BACKGROUND Figure 3.9: BPMN extension in the domain of costs based on colors (Lodhi et al., 2011) Table 3.2: Advantages and disadvantages of visualization techniques Visualization Advantages Disadvantages technique Markers Relatively easy to understand Limited in expression by standard BPMN elements (New) Symbols Flexible in expression Not necessarily understood right Text Can capture very specific information Unreadable and complex models Color Cognitive effective Users not always able to discriminate colors So, multiple visualization techniques are and can be used in extending BPMN. However, it is hard to decide which visualization technique is suitable for a certain extension. None of the visualization techniques seems to stand out. They are all used multiple times, even in combination with each other. Obviously, the required concepts to model are of influence in deciding upon the visualization technique, but for the majority of the existing extensions the decision process on their graphical notation is not mentioned at all. As Braun & Esswein (2014) already concluded, most of the extensions are developed in an ad hoc manner and do not follow a structured method. Furthermore, an evaluation on the graphical notation and its effectiveness is rarely conducted. Only the paper of Fernández et al. (2010) discusses the validation on whether the visual appearance of their simple-bpmn extension is more effective than that of standard BPMN. Most papers on BPMN extensions propose a syntax and demonstrate it via an example process. An example process might validate the syntax of a BPMN extension, but the graphical notation is left out. Still, it is possible to validate a notation as well. Many research is done on determining the quality of process models and notations (Genon et al., 2010; Mendling, 2012; La Rosa et al., 2011; Maes & Poels, 2007; Claes et al., 2015). This research aims to fill in the gaps mentioned above by using a structured methodology to develop a BPMN extension. Extra attention is paid to describing the decisions made in the design process of the graphical notation. Furthermore, a specific focus is on the validation of the notation. In deciding upon the best design option, the Physics of Notations theory from Moody (2009) is used to assess the cognitive effectiveness. Additionally, the user experience of the design options is determined in interviews with experts. The final design is implemented and tested in practice as well. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 19

33 CHAPTER 3. THEORETICAL BACKGROUND 3.3 Human Factors and Ergonomics The application domain on which this research focuses is that of human factors in manufacturing. As described in Chapter 1, human factors and ergonomics is the scientific discipline concerning the interaction between humans and their working environment (IEA, 2016). It has the aim to improve human condition and covers subjects such as human-machine interaction, human capabilities, teamwork and the design of tools, machines and material (Hancock & Diaz, 2002; Stanton et al., 2004). By using defined theories, principles and methods to analyze these concepts, human factors experts can evaluate human risk levels of business activities and contribute in designing ergonomic work environments (IEA, 2016). For instance, many administrative processes are performed while sitting behind a desk all day. Human factors experts can apply the principles of their discipline to calculate whether the duration of sitting exceeds the limits and thereby introduces a risk of development of work related disorders. To overcome this, they can design a suitable solution such as standing desks. From the available literature that combines human factors and operational management, 95% shows that the application of human factors in operation systems can improve both human and system outcomes (Neumann & Dul, 2010). Especially when human factors are applied in early design stages, costs of potential changes to the process can be reduced and productivity can be affected (Paquet & Lin, 2003; Neumann et al., 2006) Different Types of Human Factors Risks Human factors risks can be divided into several categories. Figure 3.10 shows the categories used by TNO, particularly Physical, Organizational, Dangerous substances, Environmental and Safety ( Each of the five categories consists of multiple risks that can be present in working activities. For instance, radiation is a environmental risk factor that can be present and the intensity of lifting and carrying activities influences physical well-being of a worker. Even though the figure only shows a few examples per category, many more exist. As mentioned in Section 2.5.2, the scope of this research are the physical risk factors. Figure 3.10: Categorization of human factors risks based on specialization domains of IEA (2016) Assessing Human Factors Risks There are several methods to evaluate the level of human factors risks. An example is the U.S. National Institute of Occupational Safety and Health (NIOSH) method to assess the risk level of lifting and carrying (Stanton et al., 2004). Since these methods are mainly developed to be used by human factors experts, they contain very specific questions and can hardly be used by someone with limited knowledge in this domain. For this reason, TNO has developed their own methodology to perform risk assessments. The checklist used in this methodology consist of three layers of questions: Level 0, Level 1 and Level 2 questions. The questions of Level 0 are used to indicate whether the type of risk is actually present. These questions are very concrete and easy to answer. In case the risk is 20 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

34 CHAPTER 3. THEORETICAL BACKGROUND not exposed in the process, the questions belonging to Level 1 do not need to be answered. The Level 1 questions are a little more detailed and aim to give a first estimation of the level of risk. These basic questions can still be answered by general business users. In case a risk is considered too high based on the Level 1 questions, the questions of the final level, Level 2, can be filled in. Level 2 questions are very specific and based on different expert methodologies such as the NIOSH method mentioned before. To clarify, Table 3.3 shows the structure of the methodology and some examples. Table 3.3: Levels of questionnaire (TNO) Depth Purpose To be filled in by Example Level 0 Determine whether Operations Manager, Do workers have to carry or lift there is exposure of Process Analyst, loads of more than 3 kilograms the risk Process Engineer, etc. manually in the course of a working day? Level 1 Give a first indication Operations Manager, Do workers have to manually of the risk level Process Analyst, carry or lift loads for more than Process Engineer, etc. two hours? Level 2 Give a detailed calculation Human Factors and What is the angle between the of the risk level Ergonomics Experts body and the lifted load at the be- ginning of the lifting task? Checklist Physical Load The checklist used to assess the risk level of physical risk factors is called the Checklist Physical Load (TNO, 2012). This checklist consists of questions for the following risk factors: 1. Lifting and carrying 2. Pushing and pulling 3. Hand-arm tasks 4. Working postures 5. Computer-related work 6. Vibration 7. Energetic overload 8. Energetic underload 9. The existence of task-related health problems Except for the last one, these risk factors are similar to the ones mentioned in Table 2.1. The existence of task-related health problems is officially not a physical risk, but as it is part of the Checklist Physical Load it is included within this research as well. The checklist uses the similar three-level structure as described before and is accessible online ( By logging in to the web page, the user can fill in the questions belonging to Level 0. For the factor Lifting and carrying, this representation of the Level 0 question is presented in Figure Figure 3.11: Screenshot of Checklist Physical Load: Level 0 questions (TNO, 2012) Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 21

35 CHAPTER 3. THEORETICAL BACKGROUND If the answer to this question is negative, the user can immediately go on to the next risk factor. However, in case the answer to this question is positive, a few more questions will appear as is presented in Figure These are the Level 1 questions and need to be filled before the next physical human factor is addressed. Figure 3.12: Screenshot of Checklist Physical Load: Level 1 questions (TNO, 2012) If the questions are filled in for every category, an overall result is shown. A screenshot from this evaluation form is presented in Figure For each physical risk factor, this evaluation form displays the level of risk in the shape of colored dots complemented by textual descriptions. When the risk level is high, a red dot will be shown. This dot is green when the level of risk is low. In addition to the level of risk, the evaluation form also shows links to advanced assessment methodologies in case a risk is considered too high. These specialized questionnaires are the Level 2 questions which need to be filled in by human factors and ergonomics experts. Figure 3.13: Screenshot of Checklist Physical Load: Evaluation form (TNO, 2012) In this research, the questions from the Checklist Physical Load are used in developing the BPMN extension. By integrating the questions and BPMN, the extension shall enable a processoriented analysis of physical risk factors. Instead of presenting the results in one evaluation form, the BPMN extension shall visualize the physical risks on the activities in a process model. This makes it possible to see exactly where in the process the risks are present. Basically, the questions from the Checklist Physical Load will need to be filled in for each activity separately and based on the result, the visual appearance of the activity element shall change. Since the BPMN extension is developed for Process Owners, such as operations or production managers, rather than human factors experts, the BPMN extension is based on the Level 0 and 1 questions. However, it should be noted that if an analysis with the BPMN extension results in activities with increased-risk, the Level 2 questions should still be addressed for those activities. 22 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

36 Chapter 4 Design Options This chapter describes the first part of the Design phase of the research project and provides an answer to the third subquestion. To rephrase, the aim of the design is to enable a process oriented analysis of human factors risks. This is done by integrating the Checklist Physical Load as described in Section with BPMN. However, instead of filling in the checklist for a whole process, the risk assessment shall be linked to each human activity individually. After filling in these questions for a specific activity, the results shall be visualized on the activity element itself. When doing this for each human activity within a process model, the process model shall provide a process oriented overview of the results of the risk assessment. In the Design phase, a visualization is developed for presenting these results. In doing so, the findings of the analysis of visualization techniques in Chapter 3 are taken into account. The design on how to perform the assessment is left out of scope as the way of filling in questions is related to user interaction design rather than BPMN. For representing the risk assessment results, three conceptual designs are developed and compared in order to decide upon the best design. This chapter describes the first part of this design process, particularly the decision process on the three conceptual designs. In Section 4.1, some general design decisions are mentioned. Section 4.2 describes the design options one by one. For each of them the decisions on the first draft are argued, the feedback of the human factors experts is summarized and an updated design is presented. 4.1 General Design Decisions This section describes the general design decisions. First, it is decided to extend the activity elements of standard BPMN rather than to introduce totally new artifacts. The reason for this is that the physical risk is considered a property of an activity as it is determined by the characteristics of that activity. For instance, the duration of a computer-related task is crucial in determining whether the activity can reduce a worker s well-being. Using a computer for an hour a day will not harm anyone, but if this task takes many more hours a day serious problems could occur. Introducing new elements would only cause confusion as it would split up properties from the object they belong to. So, the first general design decision reads as follows: GD 1 : Extend the existing BPMN activity element Secondly, it is decided that this extended activity element should replace the existing BPMN element of manual and user tasks. Standard BPMN allows for defining types of activities. For instance, there are service tasks which are automated or message tasks that define the activity of sending or receiving a message. As the risk analysis is only relevant for activities involving humans, it would not be logical to perform this analysis for activities that are not related to people, such as service tasks. Generally, tasks involving humans are presented by a manual or user task in BPMN. Therefore, the second general design decision is: Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 23

37 CHAPTER 4. DESIGN OPTIONS GD 2 : The extended activity element is a replacement for the manual and user activity element in standard BPMN Furthermore, it is determined what information the user should be able to derive from the extended activity element. As mentioned before, the BPMN extension should visualize the results of the Checklist Physical Load which consists of three components: risk level, risk type and the links to level 2 questions. However, these components might not all be relevant for the stakeholder the BPMN extension is designed for, particularly the Process Owner. The Process Owner mainly uses process models to have an overview of their process and monitor the performance. Hence, the to-be designed BPMN extension should be able to visualize the performance regarding human factors while overseeing the whole process. This can be achieved by showing the risk level on the activity elements. Moreover, the Process Owner should see the risk type that is present as he needs to make the final decisions on the process redesign as well. By knowing which activities may cause problems for workers and the type of cause, these final decisions can be made more fundamentally. For instance, if a Process Owner knows that workers can get physical problems due to the usage of vibrating tools, he will take other measures than when this increased risk is caused by prolonged standing. The link to level 2 questions is less relevant to visualize. Once the Process Owner has made the decisions on how to handle an activity with increased risk, he would probably outsource the task to a process engineer or analyst in the domain of human factors. They will then be responsible for filling in the more detailed questions of level 2. Summarizing, the third general design decision is stated as follows: GD 3 : The user should be able to derive the risk level and type from the design Based on the findings on visualization techniques used in existing BPMN extensions, it is decided to prevent from a design that only uses color to express information. As described in Chapter 3, colors limit the extent to which the BPMN extension can be used in sketches and automatically disables color blind people to use the it. Therefore, the fourth general design decision is: GD 4 : Do not use color as the only visualization technique to represent certain information Lastly, it is decided to preserve the representation of standard BPMN elements as much as possible. This makes the extension recognizable and easier to understand for users with experience in BPMN. Thus, in case a design uses markers, they are located in the upper left corner of the activity element as this is consistent with the way information on activities is expressed in standard and other BPMN extensions as well (Allweyer, 2016; Polderdijk, 2016). This leads to the last general design decision: GD 5 : Preserve the representation of standard BPMN elements as much as possible 4.2 Design Options This section describes the three conceptual designs in more detail. In each design, the general design decisions described in the previous section are taken into account. Basically, each design consists of decisions made on three aspects: 1. The visualization of the risk level 2. The visualization of the risk type 3. The kind of interaction to see the risk type 24 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

38 CHAPTER 4. DESIGN OPTIONS For each aspect, three design options are used in this research. Short brainstorm and sketching sessions have provided the three different options as presented in Table 4.1. Each option has a different starting point. The traffic light is based on the current visualization in the Checklist Physical Load, the warning sign is based on markers that are regularly used in existing BPMN extensions and the first draft of the person icon is purely based on basic shapes, particularly a circle. In principle, Table 4.1 provides 27 (3 3 3) designs as the options on the different aspects can be combined in various ways. Since testing 27 design options against each other is not feasible within the given time limits, it is decided to create only three designs in which each option from the framework is used once. That way, it is easier to perform a comparative evaluation, but still each option is evaluated. Table 4.1: Design options Risk level Risk type Interaction Traffic light Icons Directly present on element (No interaction) Warning sign (Extensive) Text annotation Click Person icon (Short) Text annotation Hover over Design I (Traffic light, Icons, Present) The notation of Design I, presented in Figure 4.1, is based on the current visualization used by TNO to express the level of risk, but this design visualizes the results for each activity separately. It is decided to use a similar representation, since this is recognizable for users that already have worked with the Checklist Physical Load. (a) Undefined (b) No risk (c) One risk (d) Multiple risks Figure 4.1: Design I: Representation of risk level and type As previously mentioned in Chapter 3, the results of the Checklist Physical Load are represented by green and red dots. Design I partly copies this representation by using the icon of a traffic light. Here, not only the color but also the order of the lights is used to determine the level of risk. Traffic signals often serve as a display mechanism in information dashboards as they clearly express their meaning without taking up too much space (Few, 2006). According to Kosara (2007) this design is a pragmatic visualization, since it satisfies the minimal set of requirements: it is based on (non-visual) data (1), it produces an image (2) and the result is readable and recognizable as traffic lights are generally known (3). In addition to the traffic light, Design I also contains markers describing the type of risk. These are located in the upper right corner. The reason for using icons instead of text is that icons have built-in mnemonics (Petre, 1995). These mnemonics are based on previously-learned associations between objects and functions which speeds up recognition (Moody, 2007). For each of the nine physical risk factors, an icon is chosen in similar color and style. Besides that the risk type can be determined from the icons, also the amount of risk types that are present can be derived from it. The more icons are shown on the activity element, the more risk types are present. If the activity elements becomes to crowded, the user directly knows something is wrong. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 25

39 CHAPTER 4. DESIGN OPTIONS The most important areas of improvement that are mentioned by the human factors experts after showing the first draft are: The icons take up too much space, which leaves little room for the actual name of the activity. Based on user data from the Checklist Physical Load it is calculated that the average number of different risk types per process is about four items. If all these would be presented in the same activity, this implies that there will be four different icons on one activity element. Displaying that many icons on one element takes up too much space and makes the elements almost unreadable. Not all icons are comprehensible enough. The traffic light implies that there are three levels of risk, whereas the checklist Physical Load only uses two risk levels. Based on these areas of improvement, the design is updated. First of all, the traffic light is adjusted from having three lights to having two as the center orange light does not serve any purpose. Removing this superfluous light automatically created more space for the text field. Furthermore, a legend is created for the icons so users can look up their definition. Figure 4.2 shows Design I after these updates. Figure 4.3 represents the icon legend that is added. (a) Undefined (b) No risk (c) One risk (d) Multiple risks Figure 4.2: Design I: Representation of risk level and type after update Figure 4.3: Design I: Icon legend 26 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

40 CHAPTER 4. DESIGN OPTIONS Design II (Warning sign, (Extensive) Text annotation, Click) Similar to Design I, Design II uses traffic signs to express the level of risk. However, where Design I has a specific visualization for both the presence and the absence of risk, Design II only differs from standard BPMN when a risk is present. In case the answers to the questions lead to an increased risk, a warning sign will appear on the activity element. In case of a risk-free activity the element will remain the same. Figure 4.4 shows both notations. (a) No risk (b) Risk present Figure 4.4: Design II: Representation of risk level The reasoning behind this design follows from the purpose of the to-be-designed BPMN extension: to identify activities with increased risk. A Process Owner should have a quick overview of these type of activities to decide upon the redesign options. In performing this task, information on risk-free activities is redundant as the user should not focus on them. Since many researches advise to reduce redundancies in process models (Weber et al., 2011), it is therefore decided not to model this information in this design. Again, a traffic sign is used because it is capable of delivering a concrete message without taking up too much space (Few, 2006). The symbol of a warning sign is used in other BPMN extensions as well (Marcinkowski & Kuciapski, 2012; Fernández et al., 2010). In Design II the types of risk are embedded in the activity element and can only be displayed in a separate window once the user double clicks the warning sign. In that case, a pop-up window will appear in which the type of risk is mentioned by the use of text. This representation is shown in Figure 4.5. By hiding the risk types by default, a process model will have less elements and consequently be less complex. Less complex business models are easier to analyze, to use in communication with stakeholders and to evolve over time (La Rosa et al., 2011). The power of hiding information was already proven by Reijers et al. (2011) as well. The results of their research showed that the comprehensibility of complex process models can be improved by the use of sub-processes as they possess information hiding quality. It is considered that hiding information on the risk types has a similar outcome. Figure 4.5: Design II: Representation of risk types Demonstrating Design II to the human factors experts resulted in the following list of areas of improvement: The user cannot distinguish between risk-free activities and activities for which the questions still need to be answered. Also, the visual representation does not differ from that of activities Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 27

41 CHAPTER 4. DESIGN OPTIONS for which the questions are not relevant at all, i.e. activities in which humans do not have a role. This can lead to confusion and unnecessary steps while analyzing the process model. The human factors experts do not relate the warning sign to risk. In the domain of human factors, this symbol is often used to express safety rather than risk. It cannot directly be seen how many types of risk there are present at a certain activity. The only way to determine this is to count the number of text lines in the pop-up window. Since this can only be done for one activity at a time, it is difficult to prioritize the activities according to the amount of risk that is present. As a consequence of the feedback given, the design is extended with a symbol to indicate whether questions need to be filled in. Additionally, the warning sign is adapted. The triangle is replaced by a diamond. The exclamation mark and red color are retained as these are often related to errors. Furthermore, a textual notation is added close to the icon to express the amount of risks that are present relatively to the total amount of risks that could be present. The result of the update is presented in Figure 4.6. As can be seen, the outer right image shows an activity with two out of nine possible risks present. The pop-up text box to describe the risk types has not changed. (a) Undefined (b) No risk (c) Risk present Figure 4.6: Design II: Representation of risk level after update Design III (Person icon, (Short) Text annotation, Hover over) Figure 4.7 shows the visual representation of Design III. Design III uses colored markers consisting of basic shapes to represent the different states of an activity. (a) Undefined (b) No risk (c) Risk present Figure 4.7: Design III: Representation of risk level Design III is mainly based on one of the usability principles of Norman (1988), particularly that concerning user feedback. Norman (1988) argues that a system should always inform the user when his action has been completed, either successfully or unsuccessfully. This will prevent users from performing unnecessary or wrong actions such as clicking on the same button over and over again. In Design III, each state of an activity is represented by a different color and shape. Depending on the symbol, the user either needs to fill in the questions, knows that everything is O.K. or knows that some measures need to be taken. It is decided to use a combination of visual dimensions for this design. First of all, the state is indicated by a symbol for their built-in mnemonics (Petre, 1995). Additionally, color is used in order to make the symbols stand out a bit more. Studies of Christ (1975) have shown that adding color as a redundant attribute improves visual search and identification accuracy in visual 28 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

42 CHAPTER 4. DESIGN OPTIONS displays. Here, they define redundant attributes as attributes that are not directly necessary to gain the information from the display, but rather serve as a mechanism to make identification easier. Since Design III uses both shape and color to indicate the state of an activity, color is thus a redundant variable. Similar to Design II, Design III has the property of hiding information that is less important. Figure 4.8 captures a screenshot of the visual representation of an activity when the user hovers over the shape with his mouse. Only then the type of risk is shown. Figure 4.8: Design III: Representation of risk type Even though this design is preferred by the human factors experts, still some areas of improvement have been identified. The most important issues for Design III that are mentioned are as follows: The symbols that are used are not directly related to human factors. Even though the definition of the basic symbols is rather intuitive once the user knows the application domain, it is not for those who do not. This can also cause problems when, for instance, this visualization would be used in combination with another extension. Then, it is not clear whether the circles belong to the human factors extension or to another extension. When too many risks are present, the text box is not large enough to display all the risks. At first glance, no distinction can be made between activities containing many risk types and those that only contain few. Similar to Design II, the only way to determine this is to count the number of lines in the text box one activity by one. Following from this feedback, the shape of the symbol is changed into a human body. That way it is more clear what the context of the extension is. Furthermore, the color of the state in which the questions still need to be filled in is changed from blue to gray. The reason for this is that the color gray is often used to represent an undefined state within user experience design. Furthermore, a similar textual notation as in Design II is used to express the amount of risks present in an activity. This is complemented with the use of new colors. An additional color is introduced to represent activities with only few risks. In the updated design, activities with less than three risk types contain an orange icon with an exclamation mark whereas activities with more than three risk types contain a red icon with a cross. This adapted way of expressing the risk level in Design III is shown in Figure 4.9. (a) Undefined (b) No risk (c) Few risks (d) Many risks Figure 4.9: Design III: Representation of risk level after update Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 29

43 CHAPTER 4. DESIGN OPTIONS Finally, the text in the pop-up text box is adjusted. In the updated design, shorter sentences are used so it is guaranteed that the risks can all be displayed. This is shown in Figure Figure 4.10: Design III: Representation of risk type after update To summarize this chapter, Table 4.2 shows the different states of the three conceptual designs. With these three visualization next to each other, the comparative evaluation is performed. Table 4.2: Summary of conceptual designs Design Undefined No risk One risk Multiple risks I II III 30 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

44 Chapter 5 Comparative Evaluation & Final Design This chapter covers the comparative evaluation of the three conceptual designs and a description of the final design. By discussing this subject, this chapter provides the answers to the fourth subquestion of the research. Section 5.1 describes the comparative evaluation, consisting of a cognitive effectiveness and user experience assessment. The final design is exemplified in Section Comparative Evaluation The comparative evaluation is done in two ways. First of all, the principles of the Physics of Notations theory are used in a structured way to compare the different notations based on their cognitive effectiveness. This is named the theoretical evaluation and is discussed in Subsection Furthermore, the user experience of the designs is assessed by interviewing experts in the field of visualization, usability and user experience. This is called the expert evaluation and is discussed in Subsection Theoretical Evaluation: Cognitive Effectiveness There are several measures that can be used to express the quality of a notation. One of them is the cognitive effectiveness. A general definition of cognitive effectiveness reads as follows: Cognitive effectiveness is defined as the speed, ease and accuracy with which a representation can be processed by the human mind. It determines the ability of visual notations to both communicate with business stakeholders and support design and problem solving by software engineers. (Moody, 2009) Visual representations are not cognitive effective just because they are graphical. It is a property that needs to be designed into it. Sometimes textual descriptions can be far more effective than poorly designed visualizations (Moody & van Hillegersberg, 2008). A framework that can be used in designing cognitive effective representations is that of the Physics of Notations theory (Moody, 2009). The Physics of Notations theory entails a set of nine evidence-based principles that can be used to evaluate or improve the graphical representation of modeling languages. Table 5.1 summarizes these principles and gives short descriptions. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 31

45 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN Table 5.1: Principles of the Physics of Notations theory (Moody, 2009) Principle Semiotic Clarity Perceptual Discriminability Visual Expressiveness Semantic Transparency Complexity Management Cognitive Integration Dual Coding Graphic Economy Cognitive Fit Description Semantic constructs and graphical symbols should have a oneto-one correspondence Symbols should be clearly distinguishable The full range of capacities of visual variables should be used Symbols whose appearance is evocative should be used Mechanisms for handling complexity should be included Explicit mechanisms to support integration of information from different diagrams should be included Diagrams should be enriched with textual descriptions The number of different graphical symbols should be cognitively manageable When required, different visual dialects should be used The principles can be put into practice by assigning values to visual variables. Visual variables are the building blocks of a notation. They define a visual alphabet that can be used to construct any visual representation. Bertin (2011) introduces eight visual variables which are presented in Figure 5.1. By making different combinations of these visual variables while keeping in mind the principles of the Physics of Notations, a process modeling language can be designed that is cognitive effective. However, the Physics of Notations can also be used the other way around, namely to evaluate the cognitive effectiveness of an already designed notation (Moody & van Hillegersberg, 2008; Moody et al., 2009; Claes et al., 2015; Genon et al., 2010), which is the case in this research. Even though in an existing notation, the visual variables are already assigned values, it is still necessary to be aware of them when evaluating the notation. Some of the principles ask for decomposing the notation until the most detailed level, which are the visual variables. For instance, the principle of visual expressiveness evaluates the amount of visual variables used in the notation and the perceptual discriminability is calculated by the distance between the visual variables present. Figure 5.1: Visual variables according to Bertin (2011) Table 5.2 demonstrates how the visual variables of Bertin (2011) can be used to decompose the three conceptual designs. For each of the variables, it is mentioned how it applies to the visualization. However, it should be noted that this table only takes into account the visual variables that are unique to a conceptual design and are used to express information. For instance, all the designs contain a marker of a certain Size. However, this particular Size does not say anything about physical risk factors and adjusting it does not directly influence the meaning of the design. 32 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

46 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN Table 5.2: Visual variables used in conceptual designs to express specific information Principle Design I Design II Design III Location NA NA Shape Color Size NA NA NA Brightness Orientation NA NA NA Grain NA NA NA Each principle of the Physics of Notations theory can be analyzed using specific measurements. In the theoretical evaluation, this is done for the three designs by assigning scores for each of the nine principles. These scores express how well the extended notation satisfies a certain principle. Three values are used in the scoring process: +1: the design satisfies the principle completely 0: the design satisfies the principle in some ways, but not completely -1: the design does not satisfy the principle at all By adding the scores for all the principles, it can easily be seen which visualization has the highest cognitive effectiveness according to this theory. In the next subsections, the scoring of the principles is discussed in more detail for each principle. Semiotic Clarity The principle of semiotic clarity states that there should be one-to-one correspondence between semantic constructs and graphical symbols. In order to evaluate whether a notation satisfies this principle, one must count the semantic constructs and link them to the graphical symbols. Overall, four issues can occur: Symbol deficit, when a construct is not represented by a symbol. Symbol redundancy, when a single construct is represented by multiple symbols. Symbol overload, when multiple constructs are represented by the same symbol. Symbol excess, when a symbol does not represent any construct. By reducing these anomalies, semiotic clarity can maximize expressiveness, precision and parsimony of graphical notations. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 33

47 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN In order to evaluate this principle, it is determined which constructs the BPMN extension should represent such that they could be mapped onto the symbols of each visualization. For a BPMN extension in the domain of human factors, the Process Owner should be able to see the following four constructs: 1. Whether the questions are filled in, to determine whether he still needs to perform the risk assessment. 2. Whether a risk is present, to indicate for which activities actions should be taken. 3. The type of risk, to determine what kind of actions he can take to reduce the risk. 4. The number of risks that are present, to prioritize the activities with increased-risk such that he can determine which one to address first. Looking at the three designs, it clearly shows that Design I covers all the constructs. The traffic light covers the first two aspects whereas the last two can be extracted from the icons and the number of icons. On the other hand, Design II and III do not include symbols to represent the type of risk. This can only be seen after double clicking via pop-up text boxes or when the user hovers over the shape. In these situations it can be said that symbol deficit occurs, since there are constructs that are not directly presented by a symbol. Based on these findings, the scores on the principle of semiotic clarity were assigned as presented in Table 5.3. Table 5.3: Semiotic clarity scores for conceptual designs Principle Design I Design II Design III Semiotic clarity Perceptual Discriminability A notation its perceptual discriminability defines how easy and well symbols can be distinguished from each other. It can be measured by the number of visual variables on which the symbols differ and the number of perceptual steps between those two variables, i.e. the visual distance between symbols. An example of a calculation of the perceptual discriminability is shown in Figure 5.2. Here, the first two symbols differ in only one visual variable, particularly Shape. If it is assumed that the perceptual step between the values of these visual variables, Rectangle and Circle, is equal to 1, the visual distance would become 1. The second example shows two symbols that differ on two visual variables, particularly Shape and Grain. If again it is assumed that the perceptual steps of the values of these visual variables is equal to 1, then the visual distance of these two symbols becomes 2. Figure 5.2: Example of perceptual discriminability calculation When applying this to the designs of the extension, it should not only be determined whether new symbols can be discriminated from the rest of the elements of the BPMN notation, but also if the different states of an activity (risk or no risk) can be discriminated from each other. Design I introduces the traffic light, which is a totally new symbol as a marker on activity elements. Even though the Location and Orientation of this marker are comparable to that of all the other markers used in BPMN, the Shape and Color can easily be distinguished. Design I makes a distinction 34 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

48 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN between the different states of risk by the use of a different Color, green or red, and different Location, the upper or lower light of the traffic light, within the marker. However, it should be noticed that the change in Location is minor, since the symbol is quite small itself. Design II is very good in discriminating between the different states of risk, since it not only uses different symbols and colors (question mark versus exclamation mark) but also the presence and absence of the diamond shape. On the other hand, the representation used for activities without risk is equal to that of a regular activity element in BPMN. This part of the notation cannot be discriminated from standard BPMN at all. Also, the question mark alone only discriminates from other symbols by its Shape. The Color is simply black and it has a solid Grain like the other elements in BPMN. Design III scores well on both aspects. The Location and Orientation of the marker used in this visualization are equal to those of other markers used in BPMN, but the icons itself are not used yet in standard BPMN nor its extensions. The different states of risk are represented by different Colors and symbols inside the circle, which could be referred to as the inner Shape. Combining all these conclusions, the scores for perceptual discriminability were assigned as presented in Table 5.4. Table 5.4: Perceptual discriminability scores for conceptual designs Principle Design I Design II Design III Perceptual discriminability Visual Expressiveness The visual expressiveness defines to what extent the full capacity of the visual variables is used and is determined by the number of visual variables used in the notation. The visual variables used in the design can easily be extracted from Table 5.2. Design I indicates the level of risk by using different Color and Location. Furthermore, it shows the type of risk by the use of the variable Shape combined with Brightness. When a risk type is present, the brightness is set to 100% such that the icon is visible. When a risk type is not present, the brightness is set to 0% which means that the icon is not shown. Design II also uses the Brightness variable to indicate the level of risk. The warning sign is either fully present or not. Besides that, Shape and Color are used to represent the different states of an activity. Design III uses Color and Shape to indicate different constructs. Furthermore, the Brightness variable is used in representing the amount of risk types that are present. The scores belonging to the visual expressiveness are presented in Table 5.5. Table 5.5: Visual expressiveness scores for conceptual designs Principle Design I Design II Design III Visual expressiveness Semantic Transparency The principle of semantic transparency states that one must understand the definition of symbols from its representation alone (Moody, 2009). As already noticed in Section 3.2, lots of existing BPMN extensions use images of real-world objects to represent concepts. This reduces the cognitive load, since users will directly or easily recognize these concepts (Caire et al., 2013). The level of a symbol s semantic transparency cannot be expressed as a binary state, but rather as a range (Genon et al., 2010). Caire et al. (2013) divide the scale into three areas: Semantically transparent, when the meaning of a symbol is immediately understood. Semantically opacity, when the relation between a symbol and its meaning is purely arbitrary. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 35

49 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN Semantically perversity, when it is likely that novice users do not interpret the meaning of symbol right. The designs for the BPMN extension in the domain of human factors are almost all semantically transparent. Traffic lights, check marks and crosses are widely known symbols and can immediately be understood. Still, Design I does require a legend in order for all icons to be understood. The risk types they have to represent are too specific to capture in a semantically transparent icon. Furthermore, the diamond shape used in Design II is not semantically transparent. Even though it is derived from the warning sign and the exclamation mark and red color can be related to risk, the combination with the diamond shape in the symbol does not. Therefore, the scores are as presented in Table 5.6. Table 5.6: Semantic transparency scores for conceptual designs Principle Design I Design II Design III Semantic transparency Complexity Management The complexity of a process model is measured by the number of elements displayed (Moody, 2009). Many visual notations lack in scaling capability which makes it difficult to create, manage and easily read large process models containing lots of information (Citrin, 1996). However, solutions can be found to deal with this complexity. Two main complexity management practices are modularisation and hierarchic structuring. Modularisation splits up a process model into manageable pieces that can interact with each other via standardized interfaces and architectures (Langlois, 2002). In business process models this mechanism is often referred to as subprocesses (Reijers & Mendling, 2008). Hierarchic structuring makes it possible to display process models with different levels of manageable detail (Genon et al., 2010). Both techniques have proven to reduce information overload effects and with that improve understandability (Nordbotten & Crosby, 1999; Moody, 2002). Some of the conceptual designs include mechanisms to manage complexity. For instance, Design II only shows the type of risk after double clicking which reduces the amount of information a user has to process at instance. The same goes for Design III that only displays the type of risk once the user hovers over the shape. On the contrary, Design I does not contain any mechanism to reduce the information overload. In the worst case, it has to display all the nine icons belonging to all the types of risks. Therefore, the scores in Table 5.7 are as follows. Table 5.7: Complexity management scores for conceptual designs Principle Design I Design II Design III Complexity management Cognitive Integration Cognitive integration concerns the integration of models by the use of explicit mechanisms (Moody, 2009). This concerns, for instance, the link between collapsed subprocesses and the expanded models for the subprocesses. None of the designs explicitly mentions a visualization for collapsed subprocesses. In the current designs, only standalone activity elements are customized. So, even though the expanded subprocess may contain activities visualized with the BPMN extension, the collapsed subprocess is still represented in standard BPMN. Another issue where cognitive integration is important is in Design II and III. Here, the risk types are represented in a different layer and should therefore entail a mechanism to integrate this layer with the process model. Design III does so by presenting the text notation close to the 36 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

50 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN object. As the user has to hover over the shape, the text box will automatically appear next to the activity it belongs to. Design II does not include a mechanism to improve cognitive integration. The pop-up text box appears in the middle of the window and does not mention to which activity it belongs. The user has to remember himself which activity was clicked on. Combing these findings, the scores as presented in Table 5.8 are assigned to the designs. Table 5.8: Cognitive integration scores for conceptual designs Principle Design I Design II Design III Cognitive integration Dual Coding With respect to the principle of dual coding, Moody (2009) describes that graphical symbols should be complemented by textual notations. One might argue that this contradicts with some of the previously mentioned principles, as for instance visual expressiveness, where it is discouraged to use text to represent information. However, none of them disapproves the combination of both graphics and text. The dual coding theory describes thought as a combination of nonverbal images and inner speech (Paivio & Csapo, 1973) which are both processed by different mental systems (Clark & Paivio, 1991). Since each mental system has an individual and independent capacity, it is less likely that a combination of images and text will cause an information overload than a combination of images. Still, the mental system that handles visual images is superior in terms of recognition over the one that handles linguistic information (Paivio & Csapo, 1973). Two of the designs include some textual notations whereas the other, Design I, does not at all. So, obviously Design I does not use the dual coding principle. The main purpose of the textual notations of Design II and III is to explain which type of risk is present. So, strictly speaking they are not meant to complement a symbol. However, they indirectly do so by also mentioning that the risk is present. Therefore, the scores are assigned as presented in Table 5.9. Table 5.9: Dual coding scores for conceptual designs Principle Design I Design II Design III Dual coding Graphic Economy According to the principle of graphic economy, the number of graphical symbols in a notation should be manageable. Models with simple graphical syntax are easier to understand than those with highly graphical syntax (Nordbotten & Crosby, 1999). Especially novice users will get trouble reading process models containing lots of graphical symbols, since they need to memorize the meaning of all these symbols in working memory. Expert users will suffer less as they already know the meaning of the majority of symbols (Moody, 2009). Research of Miller (1956) has shown that the number of items the human mind can process at a time is limited to approximately seven (plus or minus two). Strictly speaking the three designs do not introduce any new BPMN element, but rather extend the already existing activity element. Still, it does add some new information and with that a new icon for users to focus on. For Design I, the number of icons on an activity element varies between one and ten depending on how many types of risk are present. Together with other standard BPMN elements in a process model, as for instance gateways and events, this is likely to exceed the magical number of Miller (1956). Design II and III only add one new icon to the activity element which probably would not cause any problems. This leads to the scoring as presented in Table Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 37

51 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN Table 5.10: Graphic economy scores for conceptual designs Principle Design I Design II Design III Graphic economy Cognitive Fit The cognitive fit theory states that there is not one optimal way to represent information. Different tasks or different users require different representations of the same information (Moody, 2009). Often, cognitive fit is analyzed according to two points of view: expert-novice differences and the representational medium (Genon et al., 2010). Many research has proven that there is a difference in the way novices and experts read process models. Novices find it more difficult to discriminate between symbols, are more affected by the complexity of models and have to consciously remember the definitions of symbols (Moody, 2009). The Physics of Notations state that there should at least be two different notations responding to these differences. Furthermore, notation can differ per representational medium. Computer tools can easily visualize detailed symbols. However, when sketches need to be drawn on paper this becomes a lot more difficult as it cannot be assumed that everyone has sufficient drawing skills (Genon et al., 2010). One can imagine that there is a need for a different, simpler notation for this type of medium. The cognitive fit principle allows for both as there can be a different notation for sketches on paper than for final diagrams in computer tools. The designs for the BPMN extension all just have one perspective. No difference is made between BPMN experts and novices in designing the extension. With respect to the representation medium, the symbols expressing the risk level are all designed to be used on paper as well. However, the symbols used in Design I to express the risk type are way too detailed for drawing on paper. Design II and III use interactions to show and hide the risk types. Even though these interactions cannot be used on paper, the textual descriptions to express the risk level can. Considering this, the scores for cognitive fit are assigned as presented in Table Table 5.11: Cognitive fit scores for conceptual designs Principle Design I Design II Design III Cognitive fit Combining and adding the results for all the principles shows that Design III has the highest cognitive effectiveness based on the Physics of Notations theory. Table 5.12 gives an overview of the calculation. Table 5.12: Evaluation of conceptual designs with Physics of Notations theory Principle Design I Design II Design III Semiotic clarity Perceptual discriminability Visual expressiveness Semantic transparency Complexity management Cognitive integration Dual coding Graphic economy Cognitive fit Total Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

52 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN Expert Evaluation: User Experience Another aspect of the comparative evaluation is the expert evaluation. In this phase, three user experience experts are asked for feedback on the three designs. One of them is currently active in corporate life, but also has experience in education (> 11 years of experience). Another interviewee is actively involved in research from an educational institution (> 4 years of experience) and the third interviewee is an assistant professor in user experience design (> 5 years of experience). With each of the experts an interview is held in which the designs are showed where after they are asked for feedback. Even though the interviews are held in a semi-structured way, some general remarks could be extracted. Table 5.13 shows these general quotes and the number of experts that has mentioned them per design. Table 5.13: Evaluation of conceptual designs by user experience experts Design Quote # Experts Feedback I Traffic lights are very intuitive 3 + Icons are recognizable 2 + The icons are too small to read 2 - Does not require interaction to see the risk types 1 + Using too many icons reduces its strength 1 - Element is too packed 1 - II Element is clear/not too packed 3 + Icon used to express risk level is not very intuitive 3 - Much interaction needed to see the risk type 2 - III Provides information on the application domain 3 + Element is clear/not too packed 3 + Multiple dimensions used to express the amount of 2 + risk types Hover interaction preferred over click interaction 2 + Interaction needed to see the risk type 2 - Design is most ecstatic 1 + Representation of 1/9 might become less meaningful when the amount of risk types increases 1 - As can be seen, the experts agree upon the strength of Design I lying in the use of traffic lights. They stated that traffic lights are very intuitive and it is noticed that this mechanism is regularly used in user experience design as it is immediately understood. Furthermore, the icons are perceived as a nice way to express the risk types. It is mentioned that in general icons are recognizable which makes a visualization much easier to grasp. The icons used in the BPMN extension are reasonably well understood, but the legend is perceived as a useful addition. The amount of icons used is considered manageable, but one expert has mentioned that using too many icons can reduce its strength. So, when future research should extend the BPMN extension with more risk categories it should be questioned whether the use of icons is still feasible. Moreover, two of the experts have stated that placing the icons on the activity elements makes them a bit too small to read and the activity element too packed. Thus, it is questioned whether this way of showing the icons is optimal for this BPMN element. However, a positive issue of this representation that is called is that it does not require any interaction to see the risk types. In user experience design, the quality of an interface is often measured by the amount of interaction. In general, the less clicks a user has to perform in order to complete his task, the better the usability. In contrast to Design I, the activity element in Design II is perceived as clear and not too packed by all interviewees. It is mentioned that the model becomes simpler once the risk types are hidden at instance. However, two experts have noticed that it requires a lot of interaction which Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 39

53 CHAPTER 5. COMPARATIVE EVALUATION & FINAL DESIGN is, as explained before, not that user-friendly. Furthermore, all experts have perceived difficulties in linking the icon to what it represents : the presence of risk. Even though the red color and the exclamation mark can be related to risk, it is not that easy to find a direct relation between the diamond shape and risk. According to the experts, the warning sign that was originally used would be easier to link to risk. However, they also agree that as the warning sign relates to different concepts in the application domain, using this would only cause confusion. Design III is favored by the interviewees, because it can directly be related to human factors and ergonomics. One expert has mentioned that the icons provides information on multiple aspects. Similarly to Design II, the experts agree that this representation does not make the activity element too packed. Another issue that is mentioned as positive is the use of both text and color to show the amount of risk types that are present on an activity. However, one expert has addressed that it might be better to show the amount of risk types in a percentage rather than the notation of the format 1/9. Especially when the amount of risk types covered in the BPMN extension becomes larger, the current format is less meaningful. Regarding the way risk types are presented, not much new feedback is given compared to the interaction at Design II. However, it is mentioned that the hover interaction is preferred over the click interaction as it reduces some of the interaction the user has to have with the tool. Where the pop-up text box needs to be closed by a click interaction every time the user wants to open a new one, the hover interaction does this automatically. Another interesting comment that is made is that Design III is the most ecstatic design and blends in well with the other visual elements of BPMN. Overall, it is advised by the user experience experts to continue working on Design III. 5.2 Final Design Combining the findings of the comparative evaluation, it is concluded that Design III is the best design option. Both the cognitive effectiveness and user experience evaluation lead to the best result for Design III. Therefore, this design, presented again in Figure 5.3, is chosen to implement in software. (a) Undefined (b) No risk (c) Few risks (d) Many risks Figure 5.3: Final design 40 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

54 Chapter 6 Implementation The final design is used to visualize the results of the Checklist Physical Load within BPMN. However, to calculate the results, the checklist itself should be integrated with BPMN as well. Only then the extension will allow for an analysis of human factors risks. As the checklist is interactive and uses an algorithm to calculate the risk level, the design of the extension cannot be made just on paper. Therefore, a tool is developed as an addition to this report. In this tool the BPMN extension can be tested and used to perform a physical risk factors analysis. To make a decision on what type of software to use, it is important to determine the modeling environment on which to focus. The use of process models can be divided into two environments: the design-time and runtime environment. At design-time, process models are created that express how the overall process should be performed. They show in which order tasks should be done and by whom they can be performed. At runtime, these process models are executed. Here, the criteria set at design time are evaluated based on the state of the process. In doing so, tasks can, for instance, be assigned to resources that can perform them. This research focuses on the design-time of process models. During this phase, the process models are made using visual BPMN elements. These visual elements are less important during runtime as this phase only uses the execution rules stored within the elements. Since a particular focus of this research is on the graphical notation of BPMN extensions, it is decided to leave the execution of process models out of scope. As the runtime environment is left out scope, it is not directly necessary to develop the tool within software that is able to execute process models. Knowing this, it is decided to use Microsoft Visio. Microsoft Visio is not able to execute process models, but it is an easy to use software with a specific focus on visual diagrams. Using Visual Basic for Applications and the shapesheet, a stencil and template is made that can easily be re-used. To illustrate the result, Figure 6.1 explains the layout of the tool and Figure 6.2 shows how the user can interact with it to fill in the questions. A detailed description on the usage of the tool and more screenshots are provided in Appendix B. Additionally, a screencast can be found on As an addition to implementing the risk assessment and graphical representation of Design III, two mechanisms are included to improve the usability. First of all, an on/off-switch is created. That way the user can determine whether the human factors extension should be visualized on the process model or not. It is assumed that the Process Owner does not need to have access to the results of the risk assessment at all times. For some of his operational tasks, it might be more clear if the process model is presented in standard BPMN only. For such cases, the on/off-switch is an useful feature. Moreover, a report generator is created. By clicking on the report button, Microsoft Visio automatically creates a file in which the activities with an increased risk are summarized. This report also mentions the type of risk that is present. An example report is shown in Figure 6.3. In case the user wants to focus on the activities with increased risk only, listing them in a report is sometimes quicker. Especially as he needs to communicate with novices in the area of BPMN, a report might be easier to explain. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 41

55 Figure 6.1: Screenshot of the tool: Explanation Figure 6.2: Screenshot of the tool: Level 0 questions of human factors analysis Figure 6.3: Screenshot of the tool: Report generator

56 Chapter 7 Application With the final design implemented in software, the tool is applied and tested in practice. This chapter describes the application of the tool. The results of the evaluation are discussed in Chapter 8. Both application and evaluation are performed at two manufacturing companies, particularly Thomas Regout International (TRI) and OMRON. In interviews at these companies, a BPM setting is created in which the Process Owner and Process Analyst model and analyze a process together. The role of the Process Owner is fulfilled by the interviewees. In this role, they need to deliver the input to answer the questions. The Process Analyst is responsible for the actual modeling and analysis of the process and needs to interact with the tool. This role is fulfilled by the author of this thesis. In the next two sections, the process models resulting from these sessions are described. 7.1 Thomas Regout International TRI is a manufacturing company that develops innovative telescopic slides and linear guides ( It is one of the pilot companies within the HORSE project. Their processes involve a lot of interactions between humans and machines. Therefore, their business is very suitable to apply and test the BPMN extension at. They have already modeled some of their processes in BPMN in the context of the HORSE project, so these models can easily be remade within the tool and used to perform a risk assessment with the Process Owner at TRI. The role of Process Owner at TRI is fulfilled by the director of operations. He is actively involved in the BPM processes and has experience in process modeling in BPMN. Figure 7.1 shows the end-to-end process of TRI. In general, the production process consists of three production lines (PL). PL1 covers the shaping of raw materials, PL2 concerns the chemical treatment of the materials and in PL3 the product is assembled. It should be noted that Figure 7.1 does not show elements of the BPMN extension yet. This is because the human tasks are still hidden inside the subprocesses of this high level overview. Furthermore, the subprocesses of PL1 and PL3 are collapsed as these are left out of scope in the risk assessment. Most of the physical problems occur during the manual loading and unloading in PL2, therefore it is decided to focus on this production line and these activities only. The subprocesses of manual loading and unloading of PL2 are used to perform the risk assessment. During the process of manual loading and unloading, workers have to carry heavy frames and place them on rack one by one. Then, the frames will automatically be treated chemically by the use of a machine where after the workers have to unload the rack again. The process models in Figure 7.2 and Figure 7.3 visualize these processes by the use of the BPMN extension. As can be seen, only the manual activity elements are replaced with the activity element from the BPMN extension. Since automatic activities do not involve people, it is not necessary to analyze them on physical risks. Consequently, these activities do not need to be modeled with the element from the BPMN extension. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 43

57 CHAPTER 7. APPLICATION Furthermore, the models clearly show where in the process most of the physical problems occur. For instance, the activities Pickup handful of profiles and Hang profiles one by one show red icons due to hand-arm tasks, lifting and carrying activities, prolonged standing and energetic overload as can be seen in Figure 7.2 and Figure 7.3. The visualizations in these figures provide the Process Owner with information on the presence of physical risks in the process and with that contribute to finding a suitable solution. In this case, the Process Owner might for instance consider to outsource these tasks to robots to eliminate the risk. 44 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

58 CHAPTER 7. APPLICATION Figure 7.1: End to end process model of TRI Figure 7.2: Process model of PL2.1 Manual loading of TRI Figure 7.3: Process model of PL2.3 Manual unloading of TRI Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 45

59 CHAPTER 7. APPLICATION 7.2 Omron Omron is a manufacturer of electronic products that is founded in Japan, but nowadays their factories are located all over the world ( The influence of the Japanese style of working is still visible at these factories. The processes are very structured and designed to be (almost) 100% fault proof. Moreover, they use lots of different techniques to visualize the performance of the processes for both operators and higher management. The site at which the application phase is performed consists of two parts: a distribution warehouse and a manufacturing department. In the warehouse, products are delivered by trucks where after they are sorted by the workers of the warehouse. These tasks involve the lifting and carrying of heavy loads which currently leads to sick-leave of employees. Therefore, this process is very suitable to test the tool on. At the manufacturing department, electronic components for computer-controlled machines are produced. This process involves multiple stages, varying from soldering the print board to inspection and assembly. Especially these assembly activities involve a lot of hand-arm tasks which might lead to an increased risk for workers. So, this is also a relevant process to analyze with the BPMN extension. In contrast to TRI, Omron does not participate in the HORSE project nor do they have any experience in the field of BPMN. Therefore, these models have to be made from scratch. This is done in interviews with three employees with different backgrounds: an industrial engineer from the warehouse, a leader of the production process and a mechanical engineer that designs the work-cells for the assembly processes. The next three subsections describe the process models and results of the analyses made in these interviews Warehouse Process The process of the warehouse is modeled in the interview with the industrial engineer from the warehouse. It is decided to model the process of packages arriving at the warehouse and being sorted as these involve activities in which workers have to carry heavy loads. Basically, the process starts with a truck arriving at the warehouse. The truck is unloaded and the boxes are taken off the pallets. After the box is scanned, they will be labeled and transported through the warehouse on conveyors. When it arrives at its destination, the box is taken of the conveyor and scanned again. Then the worker knows where to put the box, places it on the right pallet and scans this pallet to confirm. In this process model, swimlanes are used to indicate that the tasks of the process can be divided over four different inbound employees. It is mentioned by the industrial engineer that without the swimlanes the model is unclear with respect to the division of tasks. It can easily be noticed that this process involves lots of tasks that can cause physical problems for employees. Most of the physical risk factors concern the lifting, carrying and transportation of heavy objects as can be seen in Figure 7.4 for the activity Doos op pallet leggen. These factors cause for workers to become exhausted Production Process The production process is modeled in the interview with the production leader and is presented in Figure 7.5. The production can be divided into a few stages, where each stage consists of multiple actions to be taken by either workers, machines or combinations of the two. The production starts with the delivery of materials and transporting them to the production floor. Here, the first stage can start which is called the surface-mount technology (SMT). During this activity, which is mainly performed by machines, SMD-components are placed on the print boards. After these are carefully inspected by workers, the print boards go into wave soldering and the product can be assembled. This product goes through a final check where after it is transported to the warehouse. In contrast to the model for the warehouse process, the model for the production process does not contain swimlanes even though every activity is performed by a different employee. However, placing each activity in a swimlane for this process does not benefit the readability of the model which is why it is chosen to not use them. 46 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

60 CHAPTER 7. APPLICATION Similarly as for assembly, the model presented in Figure 7.5 gives a clear overview of the activities containing physical risk factors. The different levels of risk can easily be distinguished and for the activity Wavesolderen it is shown what types of risks are present Assembly Subprocess As can be seen in Figure 7.5, part of the production process is assembly. To see whether the BPMN extension can be applied to lower-level processes as well, it is used to model and analyze this assembly process. Assembly is performed in custom designed work-cells. Since the mechanical engineer is responsible for the design of these work-cells, his input is used for this phase. Basically, the process model of assembly consists of many small actions the worker has to take in order to assemble the product. For instance, installing the print board to the rear cover, folding a package box and labeling it. Figure 7.6 clearly shows that the assembly process involves many activity elements compared to the other two processes. Each of them covers a very small step of the process. Furthermore, it can be noticed that there are not that many physical risk factors present during the activities. The only physical risks that are present are caused by prolonged standing and hand-arm tasks as can be seen for the activity Packingbox dicht. This could be due to the fact that the mechanical engineer takes human factors and ergonomics into account on forehand when designing the work-cells. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 47

61 Figure 7.4: Process model of warehouse process of Omron Figure 7.5: Process model of production process of Omron Figure 7.6: Process model of assembly subprocess of Omron

62 Chapter 8 Evaluation The representations of the human factors analysis as presented in Chapter 7 are evaluated with the interviewees. This is done by the use of a survey based on the Technology Acceptance Model and Method Evaluation Model of Moody (2003). This survey aims to provide insights on three aspects (Davis et al., 1989), particularly: Perceived Ease of Use (PEOU): the extent to which someone believes that using the tool is effortless Perceived Usefulness (PU): the extent to which someone believes that using the tool improves job performance Intention to Use (ITU): the extent to which someone intends to use the tool The questions and results of the survey for both TRI and Omron are presented in Table 8.1. Even though the questions regarding each specific aspect are shuffled in the survey, the table represents the results per category: PEOU, PU and ITU. Also, the scale of the answers to positive questions are reversed to provide a better overview of the overall result. In addition to the survey, semi-structured interviews are held to get qualitative feedback as well. As the Process Owner of TRI is already experienced in BPMN, this evaluation particularly focuses on the additional visual layer of physical risk factors rather than the practical application. The survey made for this so called expert evaluation compares the representation of the BPMN extension to that of the Checklist Physical Load. The results of this evaluation are discussed in Section 8.1. The interviewees at Omron did not have any experience with BPMN yet which is why the process models have been made from scratch. This so called novice evaluation does not only test the added value of the visualization of physical risks, but also the practical application of the tool. Here, a larger focus is on the practical application of the BPMN extension if an organization starts using it for the first time. Section 8.2 describes the results of the evaluation at Omron. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 49

63 CHAPTER 8. EVALUATION Table 8.1: User acceptance results (-) Disagree Agree # Question Type (+) Agree Disagree PEOU 1 I found the procedure for applying the tool complex and difficult to follow - X o 4 Overall, I found the tool difficult to use - X o 6 I found the tool easy to learn + X o 9 I found it difficult to apply the tool to the modeled pro- - X o cess 11 I found the rules of the tool clear and easy to understand + X o 14 I am not confident that I am now competent to apply - X o this tool in practice PU 2 I believe that this tool would reduce the effort required to document information on physical risk factors 3 Lots of information on physical risk factors, represented using this tool, would be more difficult for users to understand + X o - X o 5 This tool would make it easier for users to verify whether + X o the activities with an increased risk are correct 7 Overall, I found the tool to be useful + X o - X o 8 Using this tool would make it more difficult to identify activities with an increased risk 12 Overall, I think this tool does not provide an effective solution to the problem of identifying activities with increased risk 13 Using this tool would make it easier to communicate information on physical risk factors to end users 15 Overall, I think this tool is an improvement to the Checklist Physical Load/current way of assessing physical risk factors ITU 10 I would definitely not use this tool to assess the risk level of activities 16 I intend to use this tool in preference to the Checklist Physical Load/current method if I have to assess the physical risk of activities in the future - X o + X o + X o - X o + X o X Director of operations (TRI, BPMN expert) o Industrial engineer of the warehouse (Omron, BPMN novice) Leader of production process (Omron, BPMN novice) Mechanical engineer of new work-cells (Omron, BPMN novice) 50 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

64 CHAPTER 8. EVALUATION 8.1 Expert User Acceptance Evaluation: Thomas Regout International Based on the results of the survey, it can be concluded that the Process Owner of TRI is very positive about the tool. Almost every question is given the highest score. He has only showed some doubt about question 13 as he is not sure whether people that are not used to work with BPMN would understand the representation. In the interview, the Process Owner has mentioned that the BPMN extension does not represent redundant information. All information is relevant with respect to his tasks. However, he has also explained that it would be nice to receive some extra information on the practical implications of the results. For instance, he would prefer that the results should entail some suggestions to improve the activities with an increased risk. It would help him in deciding which actions to take. Without the suggestions, he would need advise from, for instance, human factors experts or process engineers on how to reduce the risks. Furthermore, it is addressed that it would be nice to use the results of the physical risk assessment during runtime. That way, the physical risks of activities can be taken into account when the process models are executed and resources are allocated to tasks. The Process Owner believes that this would increase the added value of the BPMN extension. In comparing the visualizations of the BPMN extension and the results of the Checklist Physical Load, the Process Owner definitely recognizes the usefulness of representing the physical risk factors as a layer over the process model compared to the format of the Checklist Physical Load in which the results are presented for one process or task at a time. The results presented in a process model provide a much better overview. According to the Process Owner, this makes it easier to identify smaller solutions for specific activities instead of changing an entire (sub)process. With respect to the actual graphical notation of the BPMN extension, the Process Owner has noticed he would not mind having activities with increased risk pop-out even more than they do. It is suggested to use mechanisms such as text-balloons or include more color in order to make these activities stand out more. Regarding the application of the tool in practice, the Process Owner feels sufficiently competent to use the tool by himself without the help of a Process Analyst. However, it is added that this could be due to his experience with BPMN. The Process Owner has doubts whether BPMN novices would feel the same. Also, it is noticed that it would be nice to have some more information on the content of the questions. In the Checklist Physical Load, information windows are used to provide the user with more knowledge on how to fill in the question. These are absent in the BPMN extension, but are perceived as an useful addition by the Process Owner. Furthermore, the Process Owner has mentioned that he could imagine himself using the BPMN extension to perform a risk assessment, but after that he would pass it over to the process engineers such that they could come up with a solution. Naturally, he would have to give feedback and approve these solutions later on. 8.2 Novice User Acceptance Evaluation: Omron Overall, the interviewees of Omron are positive about the BPMN extension as well. However, their answers are less explicit than those of the Process Owner at TRI. The amount of experience in process-thinking and BPMN could be a reason for this. The interviewees of Omron are used to address problems on activity level rather than from a process perspective. Therefore, they are less familiar with the use and purpose of (BPMN) process modeling and they might need more time to become totally convinced of the added value and its application. Furthermore, it can be noticed that the industrial engineer of the warehouse is more positive than the leader and mechanical engineer from the production floor. This could be due to the fact that the warehouse is facing sick-leave of employees because of physical risk factors more than the production floor. Therefore, they are focusing on human factors and ergonomics which makes the tool more relevant to them. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 51

65 CHAPTER 8. EVALUATION From the interviews, it can be concluded that the BPMN extension is perceived as a powerful visualization tool to provide a clear overview of physical risks. The colors and symbols that are used within the tool are easily understood and linked to the information they express. Furthermore, it is noticed that this type of visualization could be useful in communicating the importance of human factors to other employees. With respect to the application of the tool in practice, the industrial engineer from the warehouse is the only one that has stated he would use it in practice himself. If he would apply the tool, he would create the process models himself and fill in the questions together with the workers from the warehouse. He believes that they know best how the activities are performed. The production leader has also recognized the added value of the tool, but has explained that in his role he probably would not perform these kind of analyses himself. If he would use the tool in practice, he would ask workers to fill in the questions. He believes they have more knowledge on how activities are performed and therefore do not need his help in performing the analysis. After workers would have performed the analysis, he could use the visualized results in order to make decisions. The mechanical engineer has stated that the tool, in its current format, does not quite suit his needs. In his opinion it is mainly useful for visualizing the current state of a process. In designing the work-cells for new products, the mechanical engineer analyzes the workload of operators on forehand by using ergonomic design rules according to the current state of law. Therefore, high workloads are addressed before the work-cell is operational for production. This leaves such small and comparable actions that modeling and analyzing them does not add that many value. This is a logical argument, since analyzing such small actions is not in line with the aim of the BPMN extension, namely to enable a process oriented analysis. Both BPMN and the integrated physical risk assessment are not meant to model and analyze these small actions. Therefore, the BPMN extension is indeed less useful for a stakeholder that focuses on one activity such as assembly only. In another format, the tool might be more relevant for his role. The interviewees have had no difficulties in learning how to use the tool, but it is mentioned that some basic experience in process-thinking and understanding of BPMN is required in order for them to use it on their own. One of the interviewees has mentioned that he thought it would be useful to have a step-by-step description on how to create a BPMN process model and how to perform the risk assessment afterwards. This could be solved by writing a manual on the usage of the tool. Also, it is preferred to have some more background information on the questions to assess the physical risk factors. In the analysis, it is not always clear what is meant by certain questions. To that, one interviewee has added that some of the questions are a bit oversimplified according to him. He would prefer a three or five points scale on the answers rather than the yes and no in the current format. 52 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

66 Chapter 9 Conclusion The aim of this research was to develop an extension for BPMN to enable a human factors risk assessment in a process oriented way for the manufacturing industry. This goal is achieved by delivering a practical tool in which this BPMN extension can be used to perform a physical risk assessment and visualize the results on a process model. It is developed using a defined methodology based on the regulative cycle of Van Strien (1997) which specifically focused on describing the design process and validation of the graphical notation. By applying the tool in practice, it is concluded that the BPMN extension allows for a processoriented analysis of human factors risks. Especially expert BPMN users benefit from visualizing the results of the risk assessment on process models, since it can be added as an extra layer on top of their already existing models. This reduces the effort of using the BPMN extension. Novices BPMN users should invest more time, since they need to become familiar with process-thinking and BPMN before they can effectively use the extension. If users do not have experience in BPM practices, they find it a bit more difficult to see what can be done with the results of the analysis. Overall, the BPMN extension is perceived as useful and usable by both types of users. 9.1 Contributions This design science research contributes knowledge as it has introduced new artifacts based on existing theories (Gregor & Hevner, 2013). It contributes to the existing literature in multiple ways. Primary, it has developed a BPMN extension in a domain for which very few extensions exists, particularly that of manufacturing. By introducing this new extension, it will become easier to model and analyze issues that are relevant for the manufacturing domain. Secondly, this research has combined two relevant subjects which are often considered apart from each other: operational management and human factors. Now that information on physical risk factors can be included in process models, process engineers will be more aware of them and they can be taken into account in redesign activities. As it is already proven that the application of human factors can improve both employees well-being and system performance, this BPMN extension can contribute in process optimization as well. Furthermore, this research applies and provides a structured methodology for the development of BPMN extensions. This methodology includes a well-described design process of the graphical notation and a method to validate it. Until now, BPMN extensions are often designed in an ad hoc manner and their graphical notation is rarely validated. In this research, it is shown how the Physics of Notations theory can be combined with a practical evaluation to determine the quality of a graphical notation. Lastly, this research delivers a practical tool. Even though there are still some areas of improvement, this tool can directly be used to perform a physical risk assessment on real processes. Businesses could benefit from this tool as it enables a process oriented analysis of physical risk factors and provides a clear visualization of the results on top of their process models. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 53

67 CHAPTER 9. CONCLUSION 9.2 Limitations and Future Work Even though some interesting conclusions can be drawn from this research, there are still some limitations and areas for future research left. The main recommendation for future work is to implement the design in BPM software that is able to run process models. As the focus of this research was the graphical notation of the BPMN extension, it was decided to implement the final design in Microsoft Visio. Even though this software is good in visualizing BPMN models, it is not capable of executing the process models as is the case for most BPM software. Implementing the BPMN extension in BPM software makes it possible to use the results of the physical risk assessment in executing process models. Especially when process redesign actions cannot be taken or solve the problems, decision rules in the execution of process models can be used to reduce the risk of individual workers. These decision rules are used in the allocation of resources in the runtime environment of process models and determine who can perform which task. For instance, when an activity is marked as too risky due to lifting heavy objects for too long, a decision rule can be created to define that a worker may only perform this activity for a limit amount of time. When executing the process model, this decision rule will then ensure that this lifting task cannot be allocated to a resource that has already exceeded this limit. Another area for future work is the use of the process model in performing the physical risk analysis. In the current situation, the risk assessment is performed per activity and the result is presented for each activity on its own. However, it could be imagined that a sequence of two activities with little risk can add up to a great risk when performed by the same worker. If the tool could accumulate or aggregate the assessed risks of individual activities and display them at higher process level, the results will become much more accurate. Similar to this type of adapting the graphical notation of the extension even more, future research can focus on adding other visual features to the BPMN extension as well. For instance, one might think of changing the appearance of a swimlane if it contains too many risky activities or that of a subprocess element if the activities inside have an increased risk. Furthermore, future research could focus on adding more categories of human factors risks to the BPMN extension. Currently, the BPMN extension is limited to the physical risk factors. However, as mentioned in Chapter 3, there are four other categories which are equally important, particularly: Organizational, Dangerous substances, Environmental and Safety. Adding these risk categories raises many new visualization issues as there will be a new level of information. The user might want to see the distinction between the different categories as well. This can be done in many ways. For instance, one can think of using icons on activity elements to visualize the risk category whereas the actual risk factors are still represented as a hidden layer by the hover over text box. That way, the user can immediately see the kind of risks that are present and if he needs to see more detailed information, he can hover over the shape. However, instead of using icons to represent the risk categories, also other visualization techniques such as textual notations or color can be considered. These are just a few examples of how these additional risk categories could be integrated in the BPMN extension. Naturally, there are many more options. A new design cycle should be started to see what visualization is most useful and usable. Besides adding more types of human factors risks, also more research should be conducted on the customized views for the different stakeholders of the BPM lifecycle. The current design of the BPMN extension is developed for and tested on Process Owners and is therefore limited to their preferences. However, it is considered that other stakeholders have different requirements. Some stakeholders might require more information and some might prefer a more abstract view. That different stakeholders need different views is also concluded from the evaluation at Omron. Here, the mechanical engineer has mentioned that he did not directly needed the process oriented view to perform his tasks while the industrial engineer from the warehouse does prefer to map the results of the analysis on the process model. Future research could analyze and map the requirements for each of the stakeholders and adjust the current design to create different views. It is assumed that the Process Owner has the most general requirements regarding the amount of detail so the design in this research is a good base to start from. Another issue that can be improved is the interaction with the tool. Currently, the user has 54 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

68 CHAPTER 9. CONCLUSION to interact with the system way too much in order to fill in the questions. This is due to the fact that this is left out of scope in this research as it purely focuses on the representation of the results of a human factor analysis on process models. However, this current interaction is definitely not user-friendly and could be improved in future research. In designing a better interface to improve the process of analyzing the physical risk factors, one could also consider a new way of creating activities. For instance, tasks that are performed multiple times during a process can be stored into a repository. That way the user only has to fill in the questions once and the activity element from the repository can be used immediately in creating process model. To illustrate how this could be useful, one can think of a process in which a worker has to load and unload a truck. In both cases he has to lift and carry the same objects, so the characteristics of the activities are the same. However, in a process model this is presented as two different tasks and in the current tool the user needs to perform the risk assessment for both activities separately. Using a repository in which this type of activity is already stored and analyzed on physical risk factors prevents this unnecessary action. Moreover, future work could aim to integrate the tool with Level 2 questions. At this point, the tool only includes the Level 0 and 1 questions from the Checklist Physical Load. However, if an analysis in the tool results in activities with increased-risk, the Level 2 questions should also be addressed. In this version of the tool, the user does not get any information on how and where to do this. On top of that, results of the evaluation at TRI and Omron indicate that users prefer to get concrete advise on how to solve the identified problems. Therefore, future work should aim to provide more information on this. This could, for instance, be done by extending the report or adding text annotations or links in the process model. Future research could also apply and test this BPMN extension in other domains. In this research, the focus is on manufacturing processes. However, human factors is important in lots of other domains as well such as the chemical industry, construction and forestry. It could be studied whether the design of this BPMN extension can directly be used within these domains or if customization is necessary. Finally, future research can focus on elaborating the methodology of this research. Multiple steps taken such as the user acceptance evaluation are not specific to a BPMN extension for a human factors risk assessment. They could be applicable in the development and validation of other BPMN extensions as well. Still, some steps can only be applied if the BPMN extension satisfies certain requirements. For instance, the cognitive effectiveness evaluation can only be relevant when an extension concerns a graphical adjustment to the notation. It could be studied how the methodology of this research can be made and described more generic such that it can directly be used in the development and validation of future BPMN extensions. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 55

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74 Appendix A Notation of Standard BPMN 2.0 This appendix shows the notation of standard BPMN 2.0. The poster describes the basic elements and their definitions. BPMN Business Process Model and Notation Activities A Task is a unit of work, the job to be Task performed. When marked with a symbol it indicates a Sub-Process, an activity that can be refined. A Transaction is a set of activities that logically Transaction belong together; it might follow a specified transaction protocol. An Event Sub-Process is placed into a Process or Sub-Process. It is activated when its start event Event gets triggered and can interrupt the higher level Sub-Process process context or run in parallel (noninterrupting) depending on the start event. A Call Activity is a wrapper for a globally defined Call Activity Task or Process reused in the current Process. A call to a Process is marked with a symbol. Activity Markers Task Types Markers indicate execution Types specify the nature of behavior of activities: the action to be performed: Conversations A Conversation defines a set of logically related message exchanges. When marked with a symbol it indicates a Sub-Conversation, a compound conversation element. A Call Conversation is a wrapper for a globally defined Conversation or Sub- Conversation. A call to a Sub-conversation is marked with a symbol. A Conversation Link connects Conversations and Participants. Conversation Diagram Conversation Pool (Black Box) Pool Multi Instance Pool (Black Box) (Black Box) Sub-Conversation Participant A Choreography Task Participant B A Choreography Task represents an Interaction (Message Exchange) between two Participants. Multiple Participants Marker denotes a set of Participants of the same kind. Message a decorator depicting the content of the message. It can only be attached to Choreography Tasks. Choreographies Participant A Participant A Call Sub-Choreography Choreography Participant B Participant B Participant C A Call Choreography is a A Sub-Choreography contains wrapper for a globally a refined choreography with defined Choreography Task several Interactions. or Sub-Choreography. A call to a Sub-Choreography is marked with a symbol. Choreography Diagram Participant A Initiating Participant A Message (decorator) Choreography Participant B Task Participant A Participant B Choreography Task Participant A Participant B Choreography Task Response Participant C Message (decorator) Events None: Untyped events, indicate start point, state changes or final states. Message: Receiving and sending messages. Timer: Cyclic timer events, points in time, time spans or timeouts. Escalation: Escalating to an higher level of responsibility. Conditional: Reacting to changed business conditions or integrating business rules. Link: Off-page connectors. Two corresponding link events equal a sequence flow. Standard Start Event Sub-Process Interrupting Event Sub-Process Non-Interrupting Catching Intermediate Boundary Interrupting Boundary Non- Interrupting Throwing End Standard ~ Sub-Process Marker Send Task Loop Marker Receive Task Parallel MI Marker User Task Sequential MI Marker Manual Task Ad Hoc Marker Business Rule Task Compensation Marker Service Task Script Task Sequence Flow Default Flow Conditional Flow defines the execution is the default branch has a condition order of activities. to be chosen if all assigned that defines other conditions whether or not the evaluate to false. flow is used. Gateways Pool (White Box) Collaboration Diagram Pool (Black Box) Lane Lane Message Start Event Message Flow Data Object Data Store Collapsed Subprocess Start Event Event-based Gateway Subprocess Looped Subprocess Receive Task Timer Intermediate Event End Event Pool (Black Box) Escalation End Event Attached Intermediate Error Event Ad-hoc Subprocess Signal End Event condition Task Task ~ Attached Intermediate Timer Event Link Intermediate Event Text Annotation Participant B Participant C Group Multi Instance Task (Parallel) Manual Task Collection End Event Error: Catching or throwing named errors. Cancel: Reacting to cancelled transactions or triggering cancellation. Compensation: Handling or triggering compensation. Signal: Signalling across different processes. A signal thrown can be caught multiple times. Multiple: Catching one out of a set of events. Throwing all events defined Parallel Multiple: Catching all out of a set of parallel events. Terminate: Triggering the immediate termination of a process. Data Exclusive Gateway When splitting, it routes the sequence flow to exactly one of the outgoing branches. When merging, it awaits one incoming branch to complete before triggering the outgoing flow. Event-based Gateway Is always followed by catching events or receive tasks. Sequence flow is routed to the subsequent event/task which happens first. Link Intermediate Event Parallel Multiple Intermediate Event Event Subprocess Conditional Start Event Error End Event Call Activity Exclusive Gateway Parallel Gateway Send Task Message End Event A Data Object represents information flowing through the process, such as business documents, s, or letters. A Collection Data Object represents a collection of information, e.g., a list of order items. Parallel Gateway When used to split the sequence flow, all outgoing branches are activated simultaneously. When merging parallel branches it waits for all incoming branches to complete before triggering the outgoing flow. Inclusive Gateway Exclusive Event-based Gateway When splitting, one or more (instantiate) branches are activated. All Each occurrence of a subsequent active incoming branches must event starts a new process complete before merging. instance. Complex Gateway Parallel Event-based Gateway Complex merging and (instantiate) branching behavior that is not The occurrence of all subsequent captured by other gateways. events starts a new process instance. Pool Lane Lane Task Task Pools (Participants) and Lanes represent responsibilities for activities in a process. A pool or a lane can be an organization, a role, or a system. Lanes subdivide pools or other lanes hierarchically. Swimlanes Message Flow symbolizes information flow across organizational boundaries. The order of message Message flow can be attached exchanges can be to pools, activities, or specified by combining message events. The Message message flow and Flow can be decorated with sequence flow. an envelope depicting the content of the message. Pool Pool 2011 Input Output Data Store A Data Input is an external input for the entire process.a kind of input parameter. A Data Output is data result of the entire process. A kind of output parameter. A Data Association is used to associate data elements to Activities, Processes and Global Tasks. A Data Store is a place where the process can read or write data, e.g., a database or a filing cabinet. It persists beyond the lifetime of the process instance. Figure A.1: BPMN 2.0 Notation (Berliner BPM-Offensive, 2010) Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 61

75 APPENDIX A. NOTATION OF STANDARD BPMN Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

76 Appendix B Description of the Tool This appendix describes the usage of the tool step by step. It shows some screenshots to demonstrate the interface of the tool. Section B.1 describes how a process model can be created and a human factors analysis can be performed. Section B.2 explains the use of the additional mechanisms to improve usability. These include an on/off-switch for the human factors representation and a report generator. As an addition to the description in this appendix, a screencast can be found on B.1 Human factors analysis Figure B.1 shows a screenshot of the tool when a new empty template is opened. The stencil on the left shows the BPMN elements that can be used within this template. Besides the basic elements of BPMN, this stencil also includes the extended element for human factors. Figure B.1: Screenshot of the tool: Empty template When the user wants to create a process model, the elements of the stencil can be dragged and dropped onto the worksheet. Figure B.2 shows a basic model of a fictional process made within the tool. Clearly, this process model only contains one human activity. Therefore, only one of the activities is created with the extended BPMN element. The other activities do not involve humans so it is not necessary to perform a human factors analysis on them. Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 63

77 APPENDIX B. DESCRIPTION OF THE TOOL Figure B.2: Screenshot of the tool: Process model before human factors analysis To perform the human factors analysis, the user has to right click on the human activity where after the Level 0 questions of the Checklist Physical Load are shown. This is presented in Figure B.3. Figure B.3: Screenshot of the tool: Level 0 questions of human factors analysis 64 Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes

78 APPENDIX B. DESCRIPTION OF THE TOOL The Level 1 questions pop-up in a separate window if the user indicates that a certain risk is present. Figure B.4 demonstrates how this works in case workers have to perform hand-arms tasks for over 30 minutes at an activity. Figure B.4: Screenshot of the tool: Level 1 questions of human factors analysis By filling in the Level 1, the tool automatically determines whether the risk is present. Based on the result, the grey icon either becomes green, orange or red. Figure B.5 show this representation for this example. In this case, the icon has become orange as only one risk type is present. Figure B.5: Screenshot of the tool: Process model after human factors analysis Extending BPMN for Analysis of Human Physical Risk Factors in Manufacturing Processes 65