A LIVING ENTERPRISE MODEL. L. E. Whitman Brian L. Huff, Ph.D.

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1 A LIVING ENTERPRISE MODEL L. E. Whitman Brian L. Huff, Ph.D. Automation & Robotics Research Institute The University of Texas at Arlington 7300 Jack Newell Boulevard South Fort Worth, TX 76118, USA ABSTRACT Design and analysis of an enterprise frequently requires a model of the enterprise. These models are often viewed as a means to an end and are considered to have no intrinsic value in themselves beyond the purpose for which they were created. We propose that a living enterprise model will give the model value in itself to the enterprise. In this paper, we provide an explanation of what is meant by a living enterprise model. We give an overview of enterprise modeling along with key definitions. Ongoing enterprise efforts are reviewed as they relate to a living enterprise model. We then discuss the needs and requirements of living enterprise models and list some key issues. Finally, proposed future directions are presented. KEY WORDS Enterprise Modeling, Simulation, Living Systems 1. INTRODUCTION Each discipline follows a normal trend of continuous improvement - improving the individual elements in the discipline and then integrating them into a well defined system. Shop floor automation and enterprise modeling are no different. In the early eighties, many companies had implemented factory automation in various islands on the factory floor. In the mid-eighties, these same companies were focusing on how to integrate these islands of automation. A parallel can be drawn to modeling of systems. Much of the focus was on modeling a system for a specific decision, i.e., the purchase of an expensive piece of equipment, the addition of workers, etc. In the early nineties, efforts were underway to focus on the entire enterprise, and a discipline emerged called enterprise engineering. This holistic view of the enterprise and subsequent focus on the models of systems fostered research in the area known as enterprise modeling. However, many models are still developed with a single purpose in mind. Examples of these purposes are Activity Based Costing/Management, ISO 9000, Business Process Improvement, and Systems Analysis. Once that purpose has been completed, the model loses relevancy and accuracy. This is due to the rapid change of the enterprise s environment. Whereas a throw away model may be the quickest way to accomplish the single goal, it does not provide value to the enterprise in the long term. An enterprise model must not only be accurate, current and complete, but also relevant. A systems representation of the enterprise must be considered and the enterprise model must be viewed as an integral part of the enterprise itself. This paper focuses on the problem regarding the perceived use of the enterprise model. This research proposes that unless the enterprise model is viewed as an integral part of the enterprise, the completed model is of limited value and will soon lose relevancy. The next logical step in the progressive use of enterprise models is to move from viewing the model as a tool for decision making to a necessary part of the day-to-day operations. The living enterprise model is the likely candidate for this next step. 2. ENTERPRISE MODELING Models are useful tools in the re-engineering or improvement of an enterprise. Models are useful to: provide a focus for discussion, provide a means for communicating the enterprise, provide a basis for the analysis and design of a new process, act as a baseline for continuing process improvement, and facilitate the

2 control of the real world process [1]. The focus of this paper is on the capability to control the actual enterprise. There are some issues associated with enterprise models as discussed by Fox [2]. The key issue which is dealt with in this paper is: Can an enterprise model be kept current? Additional issues are: models are viewed as simply a tool to make a decision, determining the model boundaries, keeping the model consistent, creating a useful model for the entire enterprise (different views), and defining the different terms in the model. We propose that the most reliable method for keeping the enterprise model current is to require its daily use, which also changes the perceived value of the model. The next section defines terms directly related to this paper. 2.1 Definitions It is critical that while generating and maintaining a useful model that all those involved share the same terminology. There is much in the literature about the generation of enterprise ontologies [3] [4]. For the purposes of this paper, the following definitions are used. A model is an abstract representation of reality. The modeler determines which aspects of the real system are of interest and are to be modeled. An enterprise is a complex system of cultural, process, and technology components. It is a system engineered to accomplish organizational goals. Therefore, an enterprise model is defined as a symbolic representation of the enterprise and the things that it deals with. It contains representations of individual facts, objects, and relationships that occur within the enterprise. [5]. Enactment is one characteristic of a living enterprise model. Enactment is defined as the process of turning a specification or plan into a working solution. This process should be computer assisted and fully automated. [6]. An interesting analogy is given by Masselle that Process enactment is robotics for information processing domains [7]. A living enterprise model is defined as a model which drives, and is driven by, the daily operations of the enterprise. 2.2 Review of Associated Enterprise Efforts There are several efforts that are examining the enterprise as a whole. They address both the modeling aspect and the enactment aspect CIMOSA (Computer Integrated Manufacturing - Open Systems Architecture) is a modeling framework developed by a consortium of academia and industry mostly from Europe. One of the CIMOSA efforts is directed at an integrating infrastructure for model enactment... [8]. An extension called SEW-OSA has been developed which provides a CASE tool to enact the model through interpreted code using simulation and rapid prototyping [9] TOVE (Toronto Virtual Enterprise) is an effort at the University of Toronto that seeks to create an enterprise ontology [10]. This work is of special interest as it is critical that a living enterprise model has a well-defined ontology Enterprise Project is an effort in the United Kingdom to develop an enterprise ontology and provide a method and a tool set to capture business processes and then facilitate analysis. They also propose using enterprise models for enactment [11] PIF (Process Interchange Format) [12] and PSL (Process Specification Language) [13] seek to develop a method for the exchange of process descriptions. PIF takes the interchange approach developed for business applications and PSL takes the unifying specification approach intended for manufacturing processes Enterprise Engineering Group at the Automation & Robotics Research Institute of The University of Texas at Arlington has as its mission to conduct research into the development and deployment of advanced methods, models, and tools to support enterprise engineering. The group has also defined the discipline of enterprise engineering [14]. Advanced modeling methods are being developed. One approach uses IDEF5, IDEF0, and IDEF3 to develop an integrated multi-view model. Also being developed and implemented is an enterprise improvement methodology and methods and techniques for enterprise representation, analysis, design, and implementation WfMC The Workflow Management Coalition is a non profit organization with the objectives of advancing the opportunities for the exploitation of workflow technology through the development of common terminology and standards. [15] They are currently developing a reference model and a glossary. Workflow systems may potentially become the mechanism used to enact the living enterprise model. 3. WHY A LIVING ENTERPRISE MODEL? In this section, we provide an application of living systems theory to enterprise models, discuss the needs of, the requirements of, and the issues concerning a living enterprise model.

3 3.1 Why Living? A description of the living nature of these models can be applied from living organisms. James Miller [16] developed a general theory of living systems in an effort to classify living organisms. His primary classifications were in regard to placing living systems into hierarchical levels and he proposed twenty characteristics necessary to sustain life. However, the application of his theories to this research is the organisms desire for homeostasis or stability. The Le Chatelier principle is that a stable system under stress will move in that direction which tends to minimize the stress. The first level of modification is simply no modification. Extracting from living systems theory, there are then three progressive levels of modification: adjustment, adaptation, and evolution. Adjustment is the use of existing features to respond to the change. This can be likened to minor modifications of inputs and outputs to existing activities. Adaptation is the development of new capabilities to respond to the change. This can be likened to the addition and subtraction of activities and data to the diagrams as well as changing of their relative positions. Evolution is change in the genetic structure of the model. This can be likened to performing business process reengineering to radically change the business processes and therefore the model. Evolution is usually considered occurring slowly over a long period of time, the use of the term here only applies to the radical change, not to the time span of the change. 3.2 The Need A living enterprise model has five primary characteristics: usefulness, currentness, believability, applicability as a repository, and auditability [17] Useful Models. Typically, the enterprise model is used as a tool to aid in a decision. As previously mentioned, the model is developed to aid in the decision at a finite period in time and frequently the model is then discarded. This is why model reuse is a emerging focus of research. However, if the model was considered as a vital part of the enterprise itself, then the model would inherently maintain currency and relevance. By making the model a requirement for both day-to-day operations and strategic planning, it becomes viable as a pre-eminent resource. This is key to changing the culture which perceives an enterprise model as a means to an end rather than as the end of itself Currentness. One of the chief characteristics of an enterprise model is that it provides an understanding of an enterprise. However, as time passes and an enterprise changes, the more likely it is that the model does not accurately represent the current enterprise environment. The model must maintain currency to provide value to the enterprise Believability. Most models are used to determine what-if analysis. However, there is always the underlying question of the validity of the model. The believability of a model is directly related to its currentness. However, other than the model being up-todate, there are other advantages with the believability of a model. If the modules of a living enterprise model were plug-and-play compatible, what if scenarios could be run with a simulation receiving data directly from the system itself and outputting data to the next module in the actual system. This would provide valuable and believable data when making decisions Repository. The living enterprise model also could serve as a general storehouse for all system models developed for the enterprise. This would provide a single database for process and information knowledge about the enterprise. With a properly developed ontology the living enterprise model could serve to check the consistency between different component systems of the enterprise Audit. If the model is used to aid in the decision making process and the model is then discarded, the effort necessary to audit both the model and the decision are minimized. We should seek to continuously improve our modeling and decision making skills. A living enterprise model significantly amplifies our ability to scrutinize the relevancy of the model as well as the assumptions of the model. The model may need to be more explicit in certain areas to ensure that the model facilitates the type of decision being made. This goes in hand with ensuring that decision makers fully understand the assumptions inherent in the model. 3.3 Requirements This research is directed at determining the requirements of a living enterprise model. The living enterprise model must have the following characteristics to be effective: [18] Maintainable. A key feature of the model is that the model accurately represents the enterprise at all times. Enterprises change, therefore the model must change. The model must be easily extended to incorporate changes to one aspect of the enterprise, and those changes must be easily incorporated. This leads to the question of a top-down or a bottom-up approach. The top-down approach leads to a more

4 holistic model. The bottom-up approach tends to allow for the modeling of an aspect of a system and then connecting the various components as they are validated. By concentrating only on modeling the physical aspects of the system using a bottom-up approach, a more natural development of the model is achieved [19] Dynamic. Again, as the system changes, so must the model. Most enterprise models are static. A living enterprise model must change as the system changes. It must also provide important information on both the rate of change and the reason for change Expandable. The model must also support the addition of new subsystems. Especially in phased implementations, additional aspects of the enterprise will be assimilated into the enterprise model. Therefore, it is imperative the modeling methodology be expandable to include these new models Decompositional. Models currently provide multiple levels of detail. This is primarily to provide understanding of the enterprise by various levels of management. The living enterprise model must support not only the understanding, but also the decision making and control of the system at various levels of detail Consistent with key enterprise metrics. One of the primary goals of a living enterprise model is to ensure that the model has intrinsic value. By creating the model to be consistent with current enterprise metrics, and even creating the model to drive the metrics, the model becomes an integral part of the enterprise Driven directly from actual enterprise data. The inputs to and the outputs from the living enterprise model must be actual data from the enterprise. The model must drive the enterprise and the enterprise must drive the model. This ensures model realism and believability. In addition, the living enterprise model must: Be capable of handling non-standard activities. Frequently, activities occur in an enterprise that only occur one time. These activities must be able to process through the living enterprise model. These occurrences can quickly cause the living enterprise model to lose value. This becomes a spiraling effect until the living enterprise model dies and is put on the shelf Be capable of simulating various scenarios. This is related to the previous requirement, except that it deals with the non-standard activities that do occur repeatedly. Each scenario must be modeled and incorporated into the living enterprise model to facilitate their enactment. 3.4 Issues There are many issues related to enterprise modeling in general. However, this section focuses on the key issues relating to living enterprise models. These issues include: scope of effort, maintainability, and ability to respond to process deviations Scope of effort. In modeling a system, the boundary of the system is key to both the time and the resources it takes to create the model. On the other hand, the smaller the scope of the effort, the more likely a suboptimal solution will be found with regards to the larger enterprise system which is outside of the model boundaries. This issue concerns the need for the effort to be large enough to actually impact the enterprise, yet manageable enough to be completed in a reasonable period of time Maintainability. As enterprises change, so must the model. If the model is difficult to maintain, the relevancy of the model will be lost. According to the International Conference on Enterprise Integration Technology [20], there are basic principles of changing models: The model is of no use if changes cannot be managed. The model is not manageable if metrics cannot identify what has been changed. The model is of no use if it is not synchronized with reality Ability to respond to process deviations. Most of the time spent developing a model is concerned with the typical flow through the enterprise. When a system expert is questioned about the process flow through their area of expertise, they almost exclusively discuss the typical flow. With further questioning, they will describe the significant few scenarios. With even further probing, the expert may describe the even less frequent occurrence. All of these descriptions are vital for the living enterprise model to be enacted into the daily operations. However, most experts of the system being modeled cannot foretell the future and envision every possible circumstance. For the enterprise model to be effective, it must have the ability to be quickly and easily modified to support new events. The more frequently the enacted model must be circumvented, the less relevant it becomes. This issue is directly related to

5 the previous two issues. This issue also addresses the topic of variability reduction. Variability reduction is a vital effort in process improvement. Variability must be modeled and dealt with in the living enterprise model. 4. DIMENSIONS OF THE LIVING ENTERPRISE MODEL Now that a foundation has been laid for the basis of a living enterprise model, the following dimensions of living enterprise models are proposed. The figure below shows the three dimensions of scope, enactment, and the dynamicness of the model. A description of each of these characteristics follows. 4.1 Scope Scope is the pervasiveness of the model throughout the enterprise. Enterprise modeling by its very nature is intended to provide a holistic representation of the entire enterprise. It is sometimes necessary to bound the model to a subset of the enterprise. The bounds describe the scope of the model. 4.2 Enactment Enactment is the level in which the model drives and is driven by the system. There is a wide variation in the enactment capabilities of a living model. A model can range from no enactment at all to driving the entire enterprise and providing all inputs and reporting the status of the enterprise when requested. Some more likely phases of enactment might be to use a work flow arrangement which can provide either direction to enterprise personnel allowing them to deviate slightly from the process or require strict adherence to the process. 4.3 Dynamic A model that is dynamic is able to respond to both permanent and temporary process changes to the system. As has been previously discussed, an important living characteristic of an enterprise model is its ability to change. This dimension denotes this ability. Most models today do not facilitate the ease of change for the model. The phases of dynamic range from no capability to the model itself being capable of learning from its environment and then modifying itself to reflect and implement the new process [21]. This dynamic dimension is not to be confused with simulation models which are often called dynamic representations. 5. CONCLUSION AND FUTURE DIRECTIONS This paper presented an overview of enterprise modeling, key definitions, and a review of associated efforts. We defined why the term living is used and the need and requirements for a living enterprise model along with the key issues. Dimensions of the living enterprise model were then proposed. A living enterprise model is a necessary stage in the logical progression of the Enterprise Engineering discipline to facilitate the use of enterprise models in the daily operations of an enterprise. Future research will focus on the key components of the living enterprise model and the implementation methods of these components. Each of the proposed dimensions will be further researched and gradations of each dimension will be developed. 6. ACKNOWLEDGMENTS Research for this paper is funded in part by the National Science Foundation sponsored Agile Aerospace Manufacturing Research Center. 7. REFERENCES 1. Huckvale, T. and M. Ould, Process Modelling - Who, What, How: Role Activity Diagramming, in Business Process Change: Reengineering Concepts, Methods, and Technologies, V. Grover and W.J. Kettinger, Editors. 1995, Idea Publishing Group: Harrisburg, PA. p Fox, M.S. Issues in Enterprise Modeling. in IEEE Conference on Systems, Man, and Cybernetics Fox, M.S., M. Barbuceanu, and M. Gruninger, An organisation ontology for enterprise modeling: Preliminary concepts for linking structure and behaviour. Computers in Industry, : p Gruninger, M. and M.S. Fox. An Activity Ontology for Enterprise Modeling. in Third IEEE Workshop on Enabling Technologies: Infrastructures for Collaborative Enterprises Morgantown, WV.

6 5. Presley, A.R., A Representation Method to Support Enterprise Engineering, in Industrial and Manufacturing Systems Engineering. 1997, University of Texas at Arlington: Arlington. 6. Weston, R.H. and I.A. Coutts. Model Enactment Based on use of the CIM-BIOSYS Integrating Infrastructure. in International Conference on Automation, Robotics, and Computer Vision Shagri-La, Singapore. 7. Masselle, E.L. and D.H. Rhodes. Mechanized Mechanisms: The Case for Process Enactment. in Systems Engineering in the workplace: Proceedings of the Annual International Symposium-National Council on Systems Engineering Arlington; VA: NCSOE; CIMOSA Association, CIMOSA - A Primer on key concepts, purpose and business value, Edwards, J.M., et al., Methods and Tools for Manufacturing Enterprise Modeling and Model Enactment. IEE Proceedings - Science, Measurement, and Technology, (5): p Gruninger, M. and M.S. Fox. The Logic of Enterprise Modelling. in 4th Industrial Engineering Research Conference Fraser, J. Managing Change Through Enterprise Models. in Applications and Innovations in Expert Systems II Cambridge: SGES Publications. 12. Lee, J., G. Yost, and P.W. Group, The PIF Process Interchange Format and Framework, Schlenoff, C., A. Knutilla, and S. Ray, Unified Process Specification Language: Requirements for Modeling Process,. 1996, National Institute of Standards and Technology. 14. Liles, D.H., et al. Enterprise Engineering: A Discipline? in Society for Enterprise Engineering (SEE) Conference Orlando, FL: The Society for Enterprise Engineering. 15. Anonymous, The Workflow Management Coalition Specification: Terminology & Glossary,. 1996, Workflow Management Coalition: Brussels, Belgium. 16. Miller, J., Living Systems. 1978, New York: McGraw-Hill Book Company. 17. Huff, B.L., B.J. Howell, and D.H. Liles. The Use of IDEF3 and Colored Petri Net Modeling Methods to Support Continuous Enterprise Process Improvement. in IDEF-Users Group Conference Fort Worth, TX. 18. Huff, B.L., et al. The Use of IDEF Modeling Techniques for Small Manufacturing Enterprise Modeling. in IDEF Users Group Conference Albuquerque, NM. 19. Pratt, D.B., J.H. Mize, and M. Kamath. A Case for Bottom-up Modeling. in 2nd Industrial Engineering Research Conference Los Angeles, CA. 20. ICEIMT Working Group, Modeling Methodology, in Enterprise Integration Modelling, C. Petrie, Editor. 1992, MIT Press: Cambridge, MA. p Wood, J.T., Organismic Modeling of Organizations: A Dynamic Enterprise Model, in Business. 1994, University of Texas at Arlington: Arlington, TX. p AUTHOR BIOGRAPHIES LARRY WHITMAN is a Research Engineer with the Automation & Robotics Research Institute (ARRI) of The University of Texas at Arlington (UTA). He is currently pursuing his Ph.D. degree from the Industrial and Manufacturing Systems Engineering department at UTA He received his MSIE and BSET degrees from Oklahoma State University. Prior to joining ARRI, he spent ten years in the aerospace industry integrating factory automation and developing and supporting CAD systems. His research interests are in enterprise modeling, simulation, strategic cost justification, and enterprise applications in manufacturing. BRIAN HUFF is an Assistant Professor in the Industrial and Manufacturing Systems Engineering Department at the University of Texas at Arlington (UTA). He received his Ph.D. and M.S. degrees from UTA. He received his B.S. in Petroleum Engineering from West Virginia University. His research interests are in manufacturing systems design, industrial simulation, industrial automation and robotics, and shop floor production execution and control.