Workilow-driven collaborative session management in product ...

Workflow-driven Collaborative Session Management in Product Lifecycle Management via Internet D.W. Sun', X. H. Xiong', L. W. Ruan', Z. J. Liu', J. M. Zhao', Y.S. Wong3 'Department of Electrical and Computer Engineering, National University of Singapore, Singapore 'Data Storage Institute, Singapore 'Department of Mechanical Engineering, National University of Singapore, Singapore

Abstract-With the globalization of manufacturing industry, there is an increasing need for tools to capture, represent, and exchange pmduet development knowledge. Collaborative engineering design has emerged to support distributed and collaborative product development. Product development process nowadays is featured with distributed worldlow, complicated interaction and intensive collaboration. In order to shorten pmduct lifecycle, integration of CAE functionalities with distributed engineering design environment is necessary. However, due to the complex nature of the pmduet life cycle management (PLM) such integration may cause further complications in management of collaborative sessions. This paper presents an internet-enabled distributed and collaborative framework to support both CAD and CAE collaborations. The product design process is investigated and worknow technology is applied to manage collaborative sessions. Kqvwor&--CAD,

CAE, Collaborative Engineering,

PLM

I. INTRODLICITON Today's enterprise business activities are featured with ever-increasing complexity of product configurations, diverse data resources, and multidisciplinary, geographical dispersed engineering teams. Advances in internet technology and industry information technology provide an infrastructure for corporations to establish new strategies to improve their competitiveness [l].Network-based sessions are established in distributed product design environment to support reliable collaboration between geographically dispersed engineering teams. In a collaborative session, different engineers can share the common data and communicate with each other through conference tools, such as email, instant messaging tools etc. However, in product design stage, there is an increasing need to fit computer aided design (CAD) and computer aided engineering (CAE) seamlessly in the product design process [2]. This situation brings about the new issue for collaborative product development - organizing these collaboration tasks, both CAD and CAE tasks, in product design stage. Thus, the functions of traditional network-based sessions have to be extended in order to facilitate both CAD and CAE activities, such as providing co-modeling, visualization of meshing result and engineering data. Effort has been made by several researchers to identify the key issues in distributed collaboration

activities. G. Hunnemeyer [3] describes a development process model in their research on integrated modeling and simulation environment. The product design and simulation process is divided into a series of stages and is managed by a toolset to realize scheduling, multitasking and parallel software execution. The MobiTeam framework proposed by Z. Yalniz et al. [4] can provide lifecycle monitoring during collaborative design process. External project management tool is integrated to provide project management support. And the synchronous collaboration is established to evaluate modifications under a flow mechanism. G. Zhao and 1. Deng [ 5 ] have proposed an event-driven constraint-triggered decisionpushed model to depict product design process. Negotiation, coordination and cooperation can he achieved in product design process using this model. S. P. Hernandez et al. [6] proposed a multi-channel distributed coordination protocol to organize collaborative engineering activities. The dependency relations between distributed and cooperative applications are address in the coordination protocol. Nowadays, distributed workflow management has been widely adopted to manage distributed interactive activities and monitor the collaborative product development process in product lifecycle. At the same time, collaborative sessions help geographically dispersed engineers to cooperatively carry out complicated tasks. It can be found that warknow can also play an important role in managing collaborative sessions if we can integrate workflow system with product design system and extend its functions to dynamically invoke collaborative sessions. Workflow-driven collaborative session management can achieve following benefits in a distributed CADiCAE environment: First, it can automate the product design process. This results in improved efficiency and increased throughput. Second, Real-time monitoring of collaborative sessions as well as auditing of product design processes become possible. This can reduce costs, streamlines processes and results in better session management and tracking. Third, by deploying workflow model, the reusability of activity implementations in product design process can he achieved. Finally, the distributed activities that may take. place in heterogeneous environments are well organized and the capabilities of disparate applications are well integrated. In this paper, a distributed CAD/CAE framework is presented. The product design process and collaborative sessions for collaboration tasks are investigated. Based on

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JZEE and .NET technology, the framework has seamlessly wrapped the workflow system and the product design system for the management of collaborative product design sessions which are likely to be dynamic and interdependent. Section 2 described the framework architecture. In section 3, the workflow-driven collaborative session management is discussed in detail. A product design scenario is givcn in section 4.

connections to product design client. Coordination server can verify product design sessions and update to workflow engine using XML messages. That is, when a collaborative session finishes, the corresponding updated XML message is sent from coordination server to workflow engine, and then the work flow runs to the next task. Coordination server also provides communication channel between CAE server and client, between CAE server and workflow engine in product performance analysis stage.

11. ARCHITECTURAL OVERVIEW

Traditionally, session is the term refers to the process that a collective of users connecting from various locations to work together on shared data or using conferencing tools to communicate ideas [7]. However, collaborative product design activities include asynchronous activities as well as synchronous activities. Dependencies exist between sequential activities, that is, even if one may work as an individual to perform an asynchronous collaboration activity, he still works on shared resources which may affect other collaboration activities. Thus, we extend the definition of session for product design as: The process in which multi-discipline designers, who may be from geographically dispersed locations, work together to design product model or analyze engineering results, synchronously or asynchronously, with the help of collaboration tools. In order to automate invoking collaborative sessions for design-analysis activities using workflow model, we adopt the following architecture for the whole framework. Fig. 1 shows the integrated architecture of workflow system and product design system. Considering the context where the workflow resides, the most common cnvironmental situation is that application software (including product design client, CAE solver etc.) is running on heterogeneous platforms. To enable all the participants to access workflow service easily and conveniently, thin client which is based on web browser is deployed to provide main interface between the user and the workflow editor, as what is shown in the system architecture. In this product design workflow model, all the tasks are message-driven. A workflow engine that is the core of the workflow model will be responsible for the explanation and execution of the messages. It is built on Enterprise Java Beans (EJB) technology, which is the server-side componenl architecture for the JZEE, to enable distributed, transactional, secure and portable development of product design workflow. Product design client that is based on ACIS [8] geometric kernel provides all needed functions for product modeling. Analysis module in product design client supports assignment of CAE pelpost-process parameters in product performance analysis stage. Coordination sever provides coordination functions for the whole product design process. Based on .NET remoting technology, it provides TCPIIP, HTTP and FTP

Fig. 1.Architecture of distributed CADICAE framework.

In this distributed CADiCAE framework, communication between engineering activities not only exists in synchronous collaborations, but also exists in asynchronous collaborations. In order to keep all of these activities in a manageable manner and establish collaborative sessions for specified tasks, it is necessary to define all of necessary information related to moduct design process.

111. ORGANIZING COLLABORATIVE SESSIONS

Product design process can be treated as a specialized kind of business process, in which documents, information, and tasks are “passed“ from one “stage” to another according to a set of rules. Dependencies exist in the product design stage when collaborating in asynchronous mode. In a CAE integrated system, the evaluation of product performance often requires the integrated analysis from dependable computing processes, which in most of the cases are dynamic and interdependent [9]. An effective session management scheme is needed to facilitate collaborative sessions in the proposed framework.

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A. Producr Development Process

case, a product design workflow model should be devised to keep these dependable sessions in a controlled manner.

If the tasks of product development process are performed separately, the high level of interdependence may lead to error and critical situations [lo]. In order to capture the context of a product design process using proposed framework, we present object relationships with use case diagram. Fig. 2 shows a use case diagram for a typical product design process. The diagram contains four use cases and five actors. In Fig. 2, planner has the role that plans the whole product development process. Designers follow the predefined workflow and perform product design synchronously or asynchronously. Product design workflow system accepts task specifications and generates product design workflow. Coordination system acts as a coordinator among product design, evaluation and simulation. CAE solver focuses on the simulation of product model.

A

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1

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CAESo?ver

Fig. 2. Use c a ~ ediagram far a product design flow

Collaborative design process consists of a series of discrete, sequent or parallel, sessions which have dependencies at certain stages. Figure 3 is the activity diagram for hard disk spindle motor design flow. It consists of asynchronous collaborative sessions (e.g. A and B in Fig. 3) and synchronous collaborative sessions (e.g. C and D in Fig. 3). When' collaborating asynchronously, each engineer or system entity (Fig. 2) can carry out different sessions simultaneously. These sessions may have dependencies. As shown in Fig. 3, the asynchronous sessions in product design stage A may he interdependent as stator and rotor are to be assembled to spindle motor finally. Asynchronous sessions in stage B may be dependable computing tasks which is highly interdependent, in such

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1-(

Notify Designer

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Fig. 3. Activity diagram for spindle m o o r design and analysis flow

When collaborating synchronously, engineers can carry out the same task cooperatively in the real-time (e.g. C or D in Fig. 3). They work intensely with one another, observing and understanding each other's intentions. Each participant contributes what they can in different fields of expertise at moments when they have the knowledge appropriate to the situation.

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Fig. 4. An example of workflow model in product simulation stage

B. Workflowdriven Collaborative Session Management

Due to the complexity and interdependency of product design process, there may be a lack of common understanding among the participants. Thus efficient arrangement of the workflow activities can greatly enhance the performance of the whole design process. During the execution of worktlow model, changes will have to be made to suit new environments. So a dynamic characteristic is imported to the workflow which provides the functionalities that activities can be added or dropped and collaborative sessions can be invoked automatically to facilitate new activities, also the activities' profile can be altered even when the workflow process is running. These are achieved by the flexible definition of the activities and configuration of the workflow engine. Fig. 4 shows an example of workflow model in product simulation stage. In Fig. 4, every task consists of related information, such as activity, engineer, model, time requirements etc. T3 and T4 are dependable computing tasks: T3 needs the computing results of T4 during its computing process before it proceeds to T5. In the initial workflow model, T4 is expected to finish before receiving the data request (at Jun 5 onwards) from T3. And T3 and T4 are performed in asynchronous sessions. However, due to requirements change of product model, it needs to evaluate the results generated by T3 before sending them to T4. In such case, a new task T6 is dynamically defined in workflow model while T4 and T3 are executing. Before T6 is inserted between T3 and T4, operations such as checking states of T4 and T3 are performed by workflow engine. After passing verification, T6 is added and waits for execution, and then a synchronous session is invoked by workflow system to carry out T6. The new workflow route becomes T4->T6->T3. During the execution of the product design process, collaborative sessions are managed by workflow model in which all task specifications are defined. When task attributes are changed or the connectors between different

tasks are redirected, synchronous or asynchronous sessions are invoked to facilitate these changes. Eventually, the dynamic product design workflow model can improve the flexibility and changeability of product development by effectively organizing collaborative sessions.

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Fig. 5 . A collaborative product design scenario.

is an example: the stator and rotor are designed by different engineers simultaneously. The involved participants also need to create synchronous sessions to coordinate their contributions according to a predefined or improvised planning, such as the "assembly" activity in Fig. 3. They join the online session for assembling spindle motor and discuss on the model with the help of coordination server that are implemented with the coordination protocol. When a task is completed successfully, the corresponding information is updated by coordination server to workflow engine. Then the product design will proceed to the next task.

C. Product P e r f o r m a n c e Evaluation Computing tasks that are carried out by different

CAE solvers can be regarded as asynchronous sessions (B in Fig. 3). They are executed following the pre-defined worktlow. The workflow engine will detect dependencies and their joint points to avoid conflicts among these computing tasks. The new task (e.g. T6 in Fig. 4) can he inserted and corresponding collaborative session can be invoked to solve the changeability problems in product design process. If the new tasks cannot pass the verification of workflow engine, workflow system will inform designers through coordination server to manually modify the workflow model to facilitate these new tasks. Synchronous session is also needed for engineers meeting online to analyze product performance (C in Fig.3).

V. CONCLUSION In this paper, a distributed engineering design and analysis framework is introduced. The framework can support real-time collaborative design and analysis tasks for product development. The product design flow is depicted using UML activity diagram and workflowdriven collaborative session management is introduced. It can monitor and track all design sessions in product

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design process, which result in improvement of the flexibility and changeability of product development. The spindle motor design scenario has demonstrated that the proposed framework can provide an effective and efficient platform for collaboration engineering design and analysis. Therefore, the framework can considerably reduce product time-to-market.

REFERENCES M. Porter, "Strategy and the Internet," Howard Business Review, vol. 80, pp. 6 3 ~ 7 82001 , C. Sekimoto, Energy and Mechanical Research Laboratories, Research and Development Center, Toshiha Corporation. Translated and presented by M. Y a m SI-Dentau, Inc. "Development of Concept Design CAD System," Inlernorionol A D M S User Conference, 1998 G. Humemeyer, "Integrated Modelling and Simulation Environment", in Pror IEEE Systems Rendinerr TecknoloD Confuence, pp. 311 - 319, Sept. 2003. 2. Yalniz and E. Kirdr. "Supporting Collaboration in the

Development of Tools and Dies in Manufacturing Networks," IEEE lniernnfionol Workkopr on

Pmceedingr of the 12'

Eaabling Technologies: Infrostructure

for Colloborat&

Enrerprijes (WETlCE'03). 2003. G. Zhao and I. Deng, "Caoperativc Product Design Process Modeling", The 6th Inlernofional Conference on Computer Supponed Cooperative work in Design, pp.236-242, Jul. 2001. S . P. Hernandez, K. Drira and M. I. D i z , "An efficient multichannel distribuled coordination protocol for collaboralive engineering activities," 2002 IEEE Inlernolionol Conference on Systems, Man and Cybernetics, val.1, Oct. 2002. Hans-Peter. Dommel and 1.1. Garcia-Luna-Aceves, "GROUP COORDINATION SUPPORT for Synchronous Internet Collaboration", IEEE INTERNET COMPUTING, Mar.-Apr.

1999 h~tp:llu?v~.spalial.com. D. W. Sun, L. W. Ruan, 2. 1. Liu, J. M. Zhaa, W. F. Lu and

X. G. Ming, W con currency in a Distributed Collaborative CADICAE Environment," the 11th ISPE Intemational Conference on Concurrent Eneineeting: Research and Applications, in press, Jul. 2004. [IO] W. Eversheim, H. Rarenfeld, W.Bochtler and R. Graessler, '"A Method for an Integrated Design and Process Planning based on a Concurrent Engineering Reference Model," Annals of the ClRP 44, pp. 403406,1995.

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