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Research on the application of workflow management for PLM


with the continuous deepening of enterprise informatization and the development and application of new manufacturing mode, people realize the importance of full life cycle management of product data. As an enterprise informatization strategy, PLM (Product Overall Lifecycle Management) describes and stipulates the creation, management, distribution and use of product related information in the whole life cycle, and gives an information basic framework to integrate and manage related technologies and application systems, so that users can develop, manufacture and manage products cooperatively in the process of product life cycle

workflow is proposed for a class of business processes that can be fully or partially automated. Through a series of process rules, information or tasks flow and execute among different performers. Workflow Management Coalition (WFMC) is an international workflow management organization, committed to developing unified norms and public standards for workflow technology. WFMC defines workflow as: workflow refers to the full automation or semi automation of the whole or part of the business process with the support of computer. The advantage of workflow management is to separate the application logic from the process logic.

without modifying the specific functions, the system functions can be changed by modifying the process model to complete the integrated management of part or the whole process of production and operation, so that people, information and application tools can be effectively organized together to give full play to the maximum efficiency of the system

workflow technology is widely used in various industries, including manufacturing. Large foreign companies such as EDS and PTC have achieved better workflow management in their PLM system, which greatly improves the automation of the process. However, the domestic PLM system development is still in its infancy. This paper will analyze and discuss the architecture and object model of PLM oriented workflow management system based on the development of Suzhou Valve Factory product life management system (sf-plm)

workflow management in PLM

the whole product life cycle can be divided into several stages in terms of time, such as demand definition, conceptual design, detailed design, production planning, manufacturing and assembly, sales service, operation and maintenance; Geographically, the whole product life cycle spans the entire enterprise and enterprise supply chain. PLM takes products as the core and the product supply chain as the main line to provide enterprises with a solution to optimize the management of relevant information, processes and resources at all stages of the product life cycle as a whole. Workflow management is one of the core functions of PLM system, which can be used as an enabling tool for enterprise information integration. Web based workflow management system can flexibly span the whole enterprise and its supply chain geographically, and play an important role in establishing dynamic alliance and realizing information interaction for enterprises. Workflow management technology can be easily applied to project management, change management, network collaboration and other fields, and realize business integration based on enterprise information integration. For example, in the process of product development, it enables designers to track the whole product development process, including design activities, design concepts, design ideas and design changes, send data and information to relevant users and roles in the implementation of business processes, and support the integration and automation of business processes

as shown in Figure 1, it is the functional framework of sf-plm system based on CORBA b/s three-tier network structure. In this system framework, workflow management is used as a basic management platform to connect product data in different regions and forms, making it unified and standardized product information. The sf-plm system uses CORBA as a unified distributed object computing platform to support the cross platform and complex product data integration of the system

architecture of workflow management

wfmc - workflow reference model

for the structure of workflow management system, WFMC proposed a workflow reference model (workflow reference model decided to develop a small tensile machine suitable for measuring the stress of samples before and after ozone aging test), as shown in Figure 2. Workflow reference model comes from the analysis of general workflow system structure, which is composed of four components and five interfaces. The four components are:

(1) the process definition tool (modeling tool) is responsible for the definition of workflow, and will give the formal output of the process model, which will be provided to the workflow engine for interpretation at run time

(2) workflow execution service is the core of workflow management system, which uses one or more workflow engines to provide a running environment for process instances and activities. 4. When the experimental aircraft is out of service for a long time, it is responsible for interpreting and activating the process definition, and interacting with the external resources required in the process definition

(3) management monitoring tools monitor and manage the execution of workflow, analyze, monitor and adjust the process status

(4) workflow client application is a software component used to interact with client users during workflow execution

interfaces are defined between the four components with workflow execution service components as the core. These interfaces define some standard methods and data conversion formats, which have good versatility and scalability. As can be seen from Figure 2, the workflow execution service component also defines the interface for collaboration with other workflow execution services and the interface with the invoked external application. These interfaces make the whole workflow system have good scalability and scalability

Architecture of sf-plm workflow management system

according to WFMC's workflow reference model, sf-plm workflow management system will be composed of four main modules, namely modeling tools, management tools, customer applications and workflow execution services. Because sf-plm system adopts CORBA based distributed b/s three-tier network structure, its workflow management system will also be based on CORBA and adopt distributed three-tier structure

modeling tools, management tools, and customer applications will be placed on the client, and corresponding applications will be provided according to the user type. For example, the annual output of crude steel, ethylene, cement and 10 kinds of non-ferrous metals of end users is 823 million tons, 17.04 million tons, 2.49 billion tons and 44.17 million tons. The system will provide modeling tools to facilitate the formulation and modification of workflow; If the end user is the process manager and monitor, the system will provide management and monitoring tools to facilitate process analysis, process monitoring and other management work. Because the system is based on CORBA platform, the clients have a cross platform mechanism, and the applications of these clients can serve different users on heterogeneous client platforms. Each heterogeneous client platform will request the workflow execution service on the server side through the client orb

workflow execution service will be placed in the middle layer as a part of the application business logic of the whole PLM system. It obtains the corresponding personnel role data, process control data and other process related data by accessing the database server located in the storage layer (the system uses Java JDBC to connect the database). In the middle tier, workflow execution services can also call other external application services to expand their functions

the three-tier architecture of sf-plm workflow management system established on this basis is shown in Figure 3. Because the client adopts the web technology of java graphical interface, the client only needs a web browser, which greatly enhances the flexibility of the whole system deployment. As can be seen from Figure 3, the client layer and the middle layer are transmitted through the IIOP protocol of CORBA and the HTTP protocol of web, which enables the system to shuttle freely to the internet/intranet, without the limitation of space and region

object model of workflow management

this paper uses object-oriented analysis method to analyze workflow management system, and uses UML (Unified Modeling Language) to express the analysis results

the first step of object-oriented analysis is to define the use case and establish the use case diagram of the system. Use case is used to describe the sequence of events that a participant (an external initiator) uses the system to complete a process. It can reflect the requirements of the system. The use case is a descriptive document, and the use case diagram visually shows a group of use cases of the system, the participants of use cases, and the relationship between use cases and participants

according to the workflow management architecture of the built sf-plm system, three participants and eight usage cases of user, monitor and mfcreator are analyzed. They are queryprocess (query process usage), enactprocess (execution process usage), analyseprocess (analysis process usage), monitorprocess (monitoring process usage), managewfuserole (user role management usage), Defineprocess (process definition usage), modifyprocess (process modification usage). The relationship between them can be intuitively represented by the use case diagram, as shown in Figure 4

participant user refers to a general user who can query processes and execute processes related to roles. It is the initiator of queryprocess and enactprocess. Among them, the execution order of the actitprocess usage initiated by the user is: after the user logs in to the workflow management subsystem, obtain the corresponding role information, and then the system will list the corresponding task list of the user. The user selects one of the task items and requests the workflow engine on the server side to execute the task. The workflow engine executes the task item, updates the corresponding process database and records the system log, and then returns the execution result to the US experiment on the client side. During the experiment, both ends of the specimen must ensure parallel Er (as shown in Figure 5)

participant monitor refers to a senior user with system management and monitoring authority. As can be seen from Figure 4, monitor is the initiator of the four use cases of enactprocess, analyseprocess, monitorprocess and managewfuserole. The system will provide monitor users with workflow monitoring and management tools, process execution analysis tools and user role management tools, so that monitor users can manage and monitor the execution status and operation of workflows

participant mfcreator is an engineer specialized in formulating processes and defining workflows in enterprises. The system will provide a process definition tool (process modeling tool) so that mfcreator can analyze the business process of the enterprise, formulate a reasonable workflow, and allow mfcreator to modify the established workflow. Therefore, mfcreator is the initiator of defineprocess and modifyprocess, as shown in Figure 4

use case diagrams to describe domain processes and external participants in the process, which is a very important method to describe system requirements. However, only use case diagrams cannot be used in object-oriented design. Object-oriented design must also define the specification of logic software. This specification must meet the functional requirements based on the decomposition of classes, which requires assigning "responsibilities" to each object and showing the process of interaction between objects through messages. This kind of interaction between objects can be represented by sequence diagram in UML

for this purpose, a corresponding sequence diagram should be established for all use cases of workflow management, as shown in Figure 5, which is the sequence diagram of the user initiated actitprocess use case. Userinterface (user interface object), userrole

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