Applying Collaborative Open Hypermedia Concepts to Extended Enterprise Engineering and Operation

Transcription

1 Applying Collaborative Open Hypermedia Concepts to Extended Enterprise Engineering and Operation Jörg M. Haake GMD - German National Research Center for Information Technology IPSI - Publication and Information Systems Institute Dolivostr. 15, D Darmstadt, Germany haake@darmstadt.gmd.de 1 Introduction An Extended Enterprise (EE) is a new form of organizing Business-to-Business (B2B) cooperation among business partners. Here, independent companies form a network to develop and deliver a product to a customer. An EE extends the concept of a virtual enterprise because it persists even after the product is delivered. Thus, the EE serves as a container for knowledge captured during product development and delivery, which can be used to aid partner acquisition and project organization for future projects. In an EE, cooperation occurs across organizational boundaries. Distributed teams must be formed and supported when defining and executing a joint business process. Hence, different computing infrastructures used by the different partners within an EE must be integrated. Likewise, access to the joint business process and sharing of information resources among partners must be facilitated. We believe that concepts from collaborative open hypermedia systems [9] can help to solve these problems. In this paper, first the problem of supporting engineering and operating an EE is analyzed. Then, previous approaches to supporting an EE are summarized. Next, our approach of supporting an EE using collaborative open hypermedia concepts is presented. This approach has been developed and is currently applied in the IST project EXTERNAL funded by the CEC. Finally, some conclusions are presented. 2 Problem Analysis An extended enterprise is defined as a number of partner organizations, which combine their individual capabilities and business processes, in order to perform a joint business process. As a result, a product is delivered to a customer, and it is believed that such an organization is able to deliver a product faster and cheaper compared to traditional companies. It is argued that the benefits of an EE stem from combining complementary capabilities, which would otherwise need to be acquired by a single company (which would need time and money). However, in order to realize such a benefit, good partners need to be found, and cooperation between the partners needs to be defined, coordinated, and efficiently executed.

2 The main idea here is to collaboratively define and execute a joint business process, which reflects the needs of the product to be delivered and the capabilities of the partners. The joint business process combines the individual work processes already present within each partner company. It serves as a kind of meta work process layer, which combines and extends the individual work processes of each partner into a joint work plan for the whole EE. This work plan needs to be defined and executed. Whenever the need arises, the joint work plan needs to be changed. In order to support continuous improvement, the work process execution should be captured and made available for later analysis and sharing as best practice, if necessary. Finally, the definition and execution of such a shared work plan requires support, which operates across organizational boundaries. Specifically, the different computing infrastructures in use by the different partners need to be integrated into an Extended Enterprise Network (EEN), which comprises all tools and repositories needed to share the joint work plan. We believe that such a heterogeneous environment, which requires collaborative work on heterogeneous information items (such as work process descriptions, and documents), is an ideal application area for collaborative open hypermedia systems concepts. Some requirements of such an EEN are listed below: Shared representation of joint work plan/work process (including links into individual partners work processes), partners skills and capabilities, and overall organization (e.g. actors and roles); Collaborative access to and manipulation of the shared representation by all partners; Coordination support for executing the joint work process (including enactment of work processes, and adaptation to emergent needs); Communication support facilitating cooperation among members of distributed teams; Learning support, which facilitates learning of the work process as well as capturing of best practice examples and debriefing of work process execution. Collaborative open hypermedia systems concepts can help to integrate the individual partner s work processes into a coherent whole (i.e. help maintain relationships between work processes, capabilities, and organizations), facilitate cooperative browsing and editing of such information structures, aid coordination by providing enactment support for work process structures, and provide multiple presentations of the hyperstructures (e.g. for definition, enactment, and learning purposes).

3 3 Related Work Traditionally, work execution support in enterprises has been the goal of research in workflow management systems (WFMS). Here, a few workflow designers define standard processes (so called schemas), which are then instantiated and executed by a workflow engine. At execution time, the workflow system offers tasks to be executed to employees, which are upon acceptance presented with the necessary documents and tools for carrying out the task. After task completion, results are forwarded to the next task in the work process. Ad-hoc workflow systems support the ad-hoc definition of work processes by defining next tasks on the fly. However, WFMS support only individuals in defining a work process (mostly workflow designers) instead of supporting teams in negotiating a joint work process. Furthermore, WFMS only reference work objects (such as documents) instead of maintaining integrity and facilitating cooperative access to shared information resources. Thus, a WFMS solution does not address the cooperative and emergent nature of an EE. Shared workspace systems support asynchronous and synchronous access to shared objects by distributed team members [6]. In addition, they provide awareness services [4], which help team members to perceive presence and activities of team members. Thus, coordination is facilitated. An example for a purely Web-based system using Web browsers as clients and Web servers with extensions is BSCW [1]. To support structuring of the information space BSCW only provides document lists in folders, but no task-related structure. Additionally, BSCW focuses on asynchronous work. Therefore, awareness mainly concentrates on document related events. Since version 3.2 of BSCW, synchronous awareness is provided through a user presence and activity monitor via additional Java applets. Communication is supported by a talk facility implemented using a Java applet. Since BSCW is Web-based, every kind of document can be up- and downloaded and opened with an installed application using the helper applications specification of Web-browsers. However, these applications usually are single user applications so that synchronous work is not possible. Additionally, on some machines corresponding applications might be missing and then users might not be able to access the documents. In general, shared workspace systems such as BSCW do not provide support for work process description, and enactment. Instead, work planning and execution remains under the responsibility of the users. Thus, the work orientation and coordination requirements of an EE remain to be addressed. HyperDisco [16] supports shared workspaces containing hypermedia objects and external application files that can be accessed and manipulated by heterogeneous tools. It also provides an open protocol to integrate new tools into its infrastructure. It supports asynchronous cooperative authoring with heterogeneous tools. CAOS [10] is a component-based open hypermedia system, which focuses on spatial parsing and collaboration support. Posties is a WebDAV application for collaborative work [4]. It supports asynchronous cooperative authoring over the Web. Open hypermedia systems, e.g., HyperDisco, focus on linking and integrating heterogeneous tools (and the information objects the tools work on) into an open hypermedia. They also adopt a component-based approach for developing open hypermedia services (e.g., navigational hypertext service and spatial hypertext service), but this architecture focuses on interfaces and not on run-time extensibility.

4 Some cooperative hypermedia systems were developed to support cooperative work process definition and execution. For example, Kacmar et al. [7] demonstrated the ability to integrate workflow management in a collaborative hypermedia environment through computability and a process-based model. This approach provided task and document management, while also providing cross-system capabilities in either realtime or batch-oriented services by monitoring the states of multiple hypertexts. Further, the workflow model was created in the same environment as document authoring thus providing a homogeneous work setting for all user activity. CHIPS [13] provided a shared hypermedia workspace where authors could define and execute work processes synchronously and asynchronously, and where work processes and work objects were represented in the same shared hypermedia workspace. Other open hypermedia systems include the one developed in the EuroCODE project [5], which aims at a Dexter-compliant architecture for supporting sharing of hypertexts. The hypertext model provides many structuring possibilities, but processes are not explicitly modeled in the described system. It provides a variety of cooperation modes on shared documents, but focuses on asynchronous cooperation. It uses an event notification and locking mechanism based on an object-oriented database system. Integrating the hypermedia architecture with an application sharing tool providing non-cooperation aware clients supports synchronous work. For explicit communication a conferencing system is used. A few cooperative open hypermedia systems based upon the open hypermedia model exist, such as Manufaktur [8]. In Manufaktur, spatial workspaces can be cooperatively created and populated with linked objects. However, Manufaktur does not support process modelling and enactment. As a result of this analysis we can state that previous approaches do not address all requirements of EE engineering and operation, as stated in section 2. In the next section, our approach is presented. 4 Supporting Extended Enterprise Engineering In the IST project EXTERNAL we develop infrastructure, tools and a methodology for supporting the engineering and operation of Extended Enterprises. In this paper, we focus on infrastructure and tools. 4.1 Approach Our approach can be summarized as providing an cooperative open hypermedia system, which: uses open hypermedia to represent descriptions of work processes, organizational descriptions (e.g. actors, roles, capabilities) and work objects (e.g. documents) as a nested hypermedia graph (called an EE model); provides a shared repository for the EE model and use collaborative open

5 hypermedia concepts to enables cooperative access to the shared EE model by all participants; provides open hypermedia clients as cooperative tools for browsing and manipulating the EE model stored in the repository; supports enactment of work processes by providing a workflow structure service in the cooperative open hypermedia system (COHS). In the following sub sections we discuss each issue in more detail Representing the EE Model In order to support definition and coordination of the joint business process of the EE, descriptions of work processes, organizational descriptions (e.g. actors, roles, and capabilities) and work objects (e.g. documents) are represented as a nested hypermedia graph (called an EE model). Since many components of this EE model stem from the EE partners, this EE model hyperstructure serves as a meta information structure, which binds the partners components together. Thus, heterogeneous information resources must be linked into a common structure. In addition, the types of objects to be linked will change over time (e.g. induced by changes of the environment). Thus, extensibility and tailorability need to be supported. In EXTERNAL, we use open hypermedia concepts to support the integration of arbitrary information resources. The key concept is a wrapper node type [11]. Here, a wrapper implements a shared object reference. Basically, the wrapper represents an external information resource as a node. The content attribute of this node type contains an URL pointing to the information resource. In addition, attributes are used to define which tools can be used to manipulate the content object. This way, any information item can be linked into the EE model structure, and the cooperative tools provided by the COHS can be used to display and manipulate its content (see below). By employing sub typing, new types of information objects can be added at run-time (thus, supporting extensibility) Shared Repository In order to make the shared EE model available to all partners, a shared repository containing the EE model is provided. Sharing the EE model requires two prerequisites: Firstly, a common interchange format or data model needs to be defined. In EXTERNAL we use a common XML DTD to represent the EE model in XML. Secondly, a standardized interface to the repository is needed, so that clients can access and share data via the repository. The COHS provides a repository server, which enables asynchronous and synchronous access to its content.

6 4.1.3 Cooperative Tools Cooperative tools for browsing and manipulating the EE model, which is stored in the repository, serve as clients of the cooperative open hypermedia system. A number of such clients are provided. Native clients (i.e. clients which have been written in the COHS implementation environment as described in the next section) include [11]: Cooperative content editors (e.g. for text, graphics, images), Cooperative search tool for executing queries on the shared EE model, Orientation tool for displaying hierarchical overviews on the nested EE model (including group awareness), Process definition and enactment worktop, which provides an EE portal to the users (offering links to the shared EE model and to tools working on it, including tailoring support). In addition, tools and work environments already present at the EE partner infrastructure needs to be integrated as well. Two approaches are used: Document centric integration: Tools are associated with the documents/resources they operate on (like MIME types). Thus, wrapper types can be used to encapsulate such documents/resources and to define which tool should be opened in which way on that content object. Users or COHS clients can trigger execution of the tools when traversing the structure. Process centric integration: explicit calls to the tools are stored as macro commands (e.g. persistent queries or persistent commands) on the worktop. Here, the API provided by the tools, which are to be called, is used to configure proper execution of the tool. Using both approaches, a variety of external tools have been integrated in the EXTERNAL EE engineering and operation environment [15]: The SimVision simulation tool for probabilistic simulation of work processes, The METIS visual process modelling tool, The Workware work enactment environment. In the above cases, the necessary data provided by the shared repository is specified and the target application is called. Data is either translated from the repository into the target data format (in the case of the SimVision tool) from the COHS or extracted by the called tool (in case of METIS and Workware, which can deal with the native XML format). To support cooperative work using external (non-cooperative) tools, the COHS was

7 integrated with the NetMeeting environment [11]. Thus, any non-cooperative tools can be shared in an application sharing session. For this purpose, the COHS uses its knowledge about the members and contact details of the current session, and creates a new NetMeeting session with the same members. In this session, the specified tool will be started on the respective document, and shared Support for Process Execution To support definition and execution of the joint business process, hypermedia types for representing work processes and a process execution engine, which enacts work process descriptions, are provided [11]. Here, the workflow engine is provided as a structure service in the cooperative open hypermedia system (COHS). This service interprets the shared EE model as a workflow structure. Corresponding to the server functionality in the COHS a process browser is provided as a COHS client. In this browser users can get an overview about the structure and current status (e.g. status of tasks, presence of co-workers, results of previous tasks) of the work process (see Figure 1). In addition, they can trigger execution of tasks, which are ready for execution. The browser then displays the documents needed for finishing the task, and also provides access to the tools needed for the job (using the above mentioned tools, tool integration methods). Figure 1: XCHIPS Browser In addition to process enactment, users can at any time use the browser to modify the (so far not enacted) work process description. The changes immediately take effect

8 for continued enactment. Using the cooperative tools provided, users can execute the tasks together (e.g. instead of working on a task alone). 4.2 Implementation The infrastructure provides access to and manipulation of shared hypermedia-based EE models. It serves as a basis for integrating tools and for supporting cooperative engineering and operation of extended and virtual enterprises. For wider accessibility and interoperability internet standards are used preferably. The system architecture of our approach can be characterized as client-server-based (see Figure 2). The EE models are stored in the COHS server using XML according to a hypermedia-based XML Document Type Definition (DTD). XML extends HTML because you can define your own set of tags by means of a DTD. The EE models can reference any other web resources. The server provides access to the enterprise models on the object level. Using its services, enterprise models can be created, manipulated, versioned, locked, merged, cloned and executed consistently. The server supports the HyperText Transfer Protocol (HTTP) for asynchronous access to the EE models. Asynchronous access means that usually the server sends no notifications of other user s interactions to the clients whereas synchronous access is characterized by typically fine-grained notifications of the activities of other users [2]. In order to provide synchronous access to the EE models the server uses Java's remote method invocation (RMI) in a bi-directional way for special clients. Java RMI allows Java programs running in two different virtual machines to share methods and data. This distributed object mechanism is well suited for synchronous communication between clients and server. Some very restrictive firewalls only allow incoming traffic as reply to a request. A client behind such a firewall has the problem that it cannot get notified at any time by the server so that it has to work asynchronously. If in such a case also synchronous access is needed, a proxy server could be put inside the firewall handling the communication with the remote server. Synchronous client Asynchronous client RMI HTTP COHS Shared XML EE models Figure 2: System architecture This architecture allows flexible usage of tools. All tools work on the shared EE

9 models and end-users can select tools from strictly What You See Is What I see (WYSIWIS) over loosely coupled and specially coupled until not coupled at all depending on their infrastructure and usage situation and preferences. Loosely coupled means relaxed WYSIWIS, i.e. not all-visible information is shared or not all changes on shared information are notified. Specially coupled means individual screen design so that the end-users get the same shared information presented differently. For WYSIWIS, loosely coupled or specially coupled tools synchronous Groupware clients are needed because of the notifications from the server to the clients. Our current prototype implementation is called XCHIPS ( extensible Cooperative Hypermedia Integrated with Process Support ). It is implemented in pure Java using DyCE ( Dynamic Collaboration Environment ), a Client/Server-based Java framework for the development of Groupware components [12]. Figure 3 shows the system architecture of XCHIPS. The DyCE server provides persistence for shared objects, shared object types and mobile Groupware components as well as management services, e.g. uploading and downloading of components, shared data types and shared data, transactional support for accessing and modifying shared data. The client provides a desktop for accessing components, registered to the server, and shared data, components work on. For XCHIPS, we have modeled shared hypermedia with process support on top of DyCE s shared object model and we have created several components. XCHIPS Hypermedia Workspace Tools e.g. Editors, Navigation, Search Hypermedia Workspace Model METIS visual modeller Workware SimVision COHS- Client Shared Object Model Groupware Components DyCE Network Object Mgmt. & Storage Component Mgmt. & Storage DyCE COHS Server XML Figure 3: XCHIPS Architecture Our prototype system includes the cooperative hypermedia editor, the cooperative navigation tool, the cooperative search tool, a chat tool and an audio conferencing tool based on the Java Media Framework, a shared whiteboard, a shared Web browser, a shared text editor and a shared brainstorming tool. 5 Conclusions In this paper, a COHS-based solution for supporting engineering and operation of an

10 EE was presented. XCHIPS, a prototypical implementation of the approach, uses an OHS-based approach to represent and manipulate shared EE models. COHS-features such as a collaboration structure service supporting for synchronous and asynchronous manipulation of EE models are used to facilitate cooperative work in the EE. A workflow structure service is provided, which coordinates work in the EE by enacting the EE model. This work goes beyond existing approaches for EE support. Compared to WFMS, the COHS approach presented maintains both WF structure and work objects in a unified open hypermedia workspace. Using wrappers and tool integration methods new tools and information resources can be supported by the COHS. The COHS approach goes beyond shared workspace systems due to its process support and hypertext functionality (thus, leading to an open and tailorable solution [14]). Compared to other OHS and COHS systems this work supports truly open collaboration via its support for native as well as legacy applications and through its run-time extensibility. First usage experiences with the prototype in the EXTERNAL project indicates that the approach works well for providing a unified portal to all documents and tools relevant for work coordination and execution. However, difficulties experienced include the configuration of the firewalls and the coordination of concurrent access to shared repository data from non-native tools. Here, currently a locking approach is used, which seriously limits concurrent work (this does not apply to native tools, since they underlie the more fine-grained concurrency control of the COHS server). In the future, we will address above issues. In addition, the system will be evaluated in three real-world user communities in the EXTERNAL project. References 1. Bentley, R., Horstmann, T., Trevor, J., The World Wide Web as enabling technology for CSCW: The case of BSCW, Computer-Supported Cooperative Work: Special issue on CSCW and the Web, Vol. 6 (1997), Kluwer Academic Press. 2. Delen, D., Benjamin, P. C., Erraguntla, M. An Integrated Toolkit For Enterprise Modeling And Analysis, Proceedings of the 1999 Winter Simulation Conference, IEEE Press, Dec. pp Dourish, P. and Bellotti, V. Awareness and Coordination in Shared Workspaces. In Proc. of the ACM 1992 Conference on Computer Supported Cooperative Work, Toronto, Nov. 1-4, pp Feise, J. Posties: A WebDAV Application for Collaborative Work. In Proceedings of Hypertext'00, ACM Press, San Antonio, Texas, U.S.A, pp Grønbæk, K., Hem, J.A., Madsen, O.L., Sloth, L. Systems: A Dexter-based Architecture. In Communications of the ACM 37, 2, 1994, pp Haake, J. M. Facilitating Orientation in Shared Hypermedia Workspaces. In: Stephen C. Hayne (Ed.): Group'99. Proceedings of the International ACM SIGGROUP Conference on Supporting Group Work (November 14-17, 1999,

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