Assessment of Workflow Software Tools

Transcription

1 Assessment of Workflow Software Tools Todor Stoilov, Krasimira Stoilova Institute of Computer and Communication Systems, Bulgarian Academy of Science, Sofia, Bulgaria Abstract: Workflow management systems as modelling technique for monitoring, support and control of business processes are under consideration. Problems, related to the assessment of software products, used for the design and exploitation of workflow management systems are presented. The attention is drawn towards the comparison and assessment of such software tools. The s of this assessment are presented. Keywords: software, workflow systems, web services, business processes, automation 1. INTRODUCTION Over the last decade there has been an increasing interest in information systems used to support, control, and monitor business processes. To implement automation techniques and control methods in the business processes it is necessary to apply modelling techniques for the non-technical and organizational systems and to extend the functionalities of the informational computer driven systems in the organizations. Mature technology for automating and controlling business processes are workflow management systems [1], [2]. A general task of the workflow system in the current business activities is the implementation of principles of the automatic control in business systems. One widely accepted definition of workflow comes from the workflow management coalition: Workflow is the computerized facilitation or automation of a business process, in whole or part [3]. Workflow systems use a variety of languages based on different concepts. Most of the products use a proprietary language rather than independent one. Some workflow systems are based on Petri nets but typically add product specific extensions and restrictions. The differences between the various tools are considerable. The reasons for the lack of consensus of what constitutes a workflow specification are the variety of the business processes. The absence of standard business process modelling concepts is the reason for the diversity in workflow languages. Respectively the comparison of different workflow products looks to be more as a dissemination of products than a critique of workflow language capabilities. 2. AVAILABLE METHODOLOGIES FOR SOFTWARE ASSESSMENT A set of formal languages have been worked out to support process-orientation in the context of web services - Business Process Execution Language for Web Services (BPEL4WS), Business Process Modelling Language (BPML), Web Services Description Language (WSDL), etc [2]. For choosing the most appropriate software product here arises the problem of comparison and assessment of the software products. Analysis of the available methodologies for software assessment is presented in [4,8]. A part of this analysis is Smith s criteria for software evaluation.

2 2.1. Smith s criteria for evaluation of Internet based software and informational resources The definition of a methodology for the evaluation and comparison of Internet based software products, which implement appropriate information system, offering software and informational resources is given in [5]. The evaluation is performed by applying a set of criteria for Internet based information resources like: Scope of the product. The scope of the product includes subject area, items, covered formats or types and time period. Content. The typical features related to the content of the product are the accuracy, authority, currency, its uniqueness, quality of writing, links. Graphical and multimedia design. To be synchronized with the purpose of the product presentation. Purpose or who are the potential users of the product. Workability - about convenience and effectiveness of the product. Cost The International Standard ISO/IEC 9126 The experience, which exists until now about the assessment of software and informational products, is not mature to propose to users a common easy and useful methodology for products evaluation. The evaluation methodologies does not found on an objective background, which can minimize the subjective expert influence. As an attempt to find a common objective background for the evaluation of software product here is applied the standardization approach in the assessment of the quality of the software products ISO/IEC Common notions of the standard ISO/IEC 9126 are applied to give explanations to the particular criteria, used as their hierarchical subordination for the evaluation of the quality of the software products. The standard ISO/IEC 9126 works out a quality model that categorizes software quality attributes into six characteristics, which are further sub-divided into sub-characteristics [6,7]. The standard ISO/IEC 9126 enables the software product quality to be specified and evaluated from different perspectives by those, associated with acquisition requirements, development, use, evaluation, support, maintenance, quality assurance, audit of the software. The attributes of the software quality are categorized into six characteristics [6,7]: 1/ functionality; 2/ reliability; 3/ usability; 4/ efficiency; 5/ maintainability; 6/ portability, Fig. 1. The characteristics are sub-divided into sub-characteristics, which can be measured either by internal metrics or by external metrics. software product quality functionality reliability usability efficiency maintainability portability suitability accuracy interoperability security maturity fault tolerance recoverability understandability learnability operability attractiveness time behaviour resource utilisation analysability changeability stability testability adaptability installability co-existence replaceability Fig. 1: Software product quality

3 3. EVALUATION FINDINGS It is virtually difficult to give a full overview and a detailed comparative analysis for all practically available software products and the reason that the best software product can be found in this prospective raising domain as workflow management and business process automation. It is, however, a useful exercise to make a bit general comparison of prospective products since the evaluation procedure may otherwise get lost in details and fail to see the main objective and essential characteristics of each product. This section presents comparative diagrams of the assessed workflow products. The products have been decomposed and grouped according to their general workflow functionality. Four general categories of the products have been defined: 1/Modelling Tools; 2/ Workflow Editors; 3/ Workflow Engines; 4/ Combined Products: Editor + Engine. The workflow software products have been evaluated and compared between each other for the appropriate functional category. Three different comparisons have been applied, related to the functional category of the product. Appropriate diagrams are designed. These diagrams demonstrate the advantages of a chosen product in comparison with its corresponding functional peers. Following this decomposition scheme and giving importance to the functional quality of the products, the assessment of the products are performed for four groups of products presented in Table 1. The comparative assessment of the products, belonging to the category Workflow editors and addressing their functional rating is given to the bar chart diagram, Fig. 2. Fig. 2: Workflow Editors comparative chart According to this diagram, potential candidates and winner for application in workflow developments are the products with around 4 and supporting workflow standards BPEL, XPDL. These products are Active Webflow Designer,, Enhydra JaWE, and Oracle BPEL Process Manager. Their personal rates, concerning the functional and usability software quality are presented on the pie chart diagrams. The functional comparison between the products, belonging to the category Workflow Engine and Editing and execution functionality is done. By the same way, appropriate average values have been calculated per each software category: reliability, usability, efficiency, maintainability, portability.

4 Table 1. General workflow functionality decomposition of the products Categories Modelling Tools Workflow Editors Workflow Engines Combined Products Editor + Engine Workflow Software Products Borland Together Designer Process Modeler UML Modelling Tools ActiveWebflow Designer con-cern enterprisextention Enhydra JaWE JBoss jbpm ObjectWeb BONITA Oracle BPEL Process Manager SAP NetWeaver Exchange Infrastructure YAWL ActiveBPEL Engine ActiveWebflow Standard Biztalk Server con-cern Enhydra Shark enterprisextention Freefluo JBoss jbpm ObjectWeb BONITA Oracle BPEL Process Manager SAP NetWeaver Exchange Infrastructure WfMOpen YAWL ActiveWebflow Designer + ActiveWebflow Standard con-cern Enhydra JaWE + Enhydra Shark enterprisextention JBoss jbpm ObjectWeb BONITA Oracle BPEL Process Manager SAP NetWeaver Exchange Infrastructure YAWL Then every tested product has been compared with the average s by means to identify the difference between the product quality and the average products s, Table 2.

5 Characteristics ISO/IEC 9126 Table 2. Average evaluation s per products Active BPEL Engine Active Webflow Standard Active Webflow Professional Designer BizTalk Server Borland Together 6.5 con:cern Enhydra JaWE Enhydra Shark Enterprise Xtention Functionality 4,8 4,4 3,6 2, ,6 4,2 5,2 Reliability 4,5 3,5 4,5 2,5 3 2,5 3 1,5 2,75 4,5 Usability 2,75 5 4,75 3,25 4,75 3,75 2,75 3,25 3,125 3,75 Efficiency 2,68 2,68 2,68 2,02 1,32 2,68 2,66 4 2,65 2,68 Maintainability 3,6 0,8 1,2 3,6 1,6 2 2,4 0,8 2,8 2,8 Portability 4,4 2 1,6 1,6 4,4 3,2 5, ,8 Characteristics ISO/IEC 9126 FreeFluo jbpm Bonita Oracle BPEL Process Manager Process Modeller SAP_NetWe aver WfMOpen YAWL Products Functionality 3,2 4 2,4 4,8 4 3,6 3,6 4,8 3,2 3,82 Reliability 1,5 2,5 2,5 2, ,5 5,5 2 3,05 Usability 1,5 2,25 2 3,75 4, ,25 3,75 3,46 Efficiency 2,68 2 2,68 5,34 2,68 1,32 2,02 2,66 3 2,65 Maintainability 2,8 3,6 3,2 6 0,8 2 2,8 4,8 4,4 2,74 Portability 4 3,6 1,6 5,2 3,6 3, ,8 3,2 Average value The s have been presented in a form of radar diagrams. The axis of the diagrams consist the main software quality characteristics. The area, covered by the product from the radar diagram is a measure for the potential and the performance of the product. The particular product is compared with the area, covered by the average values for the tested products, Fig.3 (a part of the evaluation is presented). Thus, the prospective product can be identified by the overlapping regions of the radar diagrams. The close overlap defines the better software product. Following the drawings of the radar diagrams, the prospective candidates are the software products: Active BPEL Engine, Active Webflow Designer,, Enhydra Shark, FreeFlue, and Yawl. 4. CONCLUSIONS The evaluations and comparisons between the software products leads to prospective set of products, defined as: Modelling tools (Borland Together Designer, Process Modeler); Editing tools (Borland Together Designer,, JBoss jbpm and Oracle BPEL Process Manager); Execution tools (Active BPEL Engine, Active Webflow Standard,, Enhidra Shark, Oracle BPEL Process Manager); Both modelling and execution tools (ActiveWebflow Standard + ActiveWebflow Designer,, Enhydra Jawe+Shark, Oracle BPEL Process Manager). These products are recommended for the implementation of workflow automation in information processes. Thus, an integration of info-services in distributed information system is achieved, which benefit the business relation between different authorities that are not under common administrative framework. The business processes are performed as tailored information services allowing different administrative rules to be performed in an automatic manner.

6 ActiveBPEL Engine ActiveWebflow Standard ActiveWebflow Designer Biztalk Server Borland Together Designer 2006 Con-cern Enhydra JaWE EnterpriseXtention Freefluo JBoss jbpm YAWL Fig.3: Pie-chart diagrams of average evaluations 5. REFERENCES [1] Kappel, G., Rausch-Schott, S., Retschitzegger, W. (2000) A Framework for Workflow Management Systems Based on Objects, Rules and Roles, ACM Computing Surveys Electronic Symposium on Object-Oriented Application Frameworks. [2] Leymann, F., Roller, D. (2000) Production workflow: concepts and techniques, Prentice-Hall. [3] Glossary, Terminology and Glossary, 3rd Edition. (1999) Document No WFMC-TC Workflow Management Coalition. Winchester. [4] Stoilova, K., Stoilov, T. (2006) Software Evaluation Approach. Proceeding of Intern. Conf. Informatics in the Scientific Knowledge 06, Varna /in print/. [5] Smith, G. (1997) Testing the Surf: Criteria for Evaluating Internet Information Resources. The Public-Access Computer Systems Review 8, no. 3. [6] [7] [8] Virtual ISP, Project no. FP , STREP, IST (FP6) (2006), Report Workflow Software Analysis and Comparison, Editor T.Stoilov. This research is partly supported by the European Commission, project FP VISP, and National Scientific Fund of Bulgaria, project ВУ-МИ-108/2005.