XML–Based Schema Definition for Support of Interorganizational Workflow

W. M. P. van der Aalst, Akhil Kumar
2003 Information systems research  
The full potential of the web as a medium for electronic commerce can be realized only when multiple partners in a supply chain can route information among themselves in a seamless way. Commerce on the Internet is still far from being "friction-free" because business partners cannot exchange information about their business processes in an automated manner. In this paper, we propose the design for an eXchangeable Routing Language (XRL) using XML syntax. XML (eXtendible Markup Language) is a
more » ... s for trading partners to exchange business data electronically. The novel contribution of our work is to show how XML can also be used to describe workflow process schemas to support flexible routing of documents in the Internet environment. The design of XRL is grounded in Petri nets, which is a wellknown formalism. By using this formalism, it is possible to analyze correctness and performance of workflows described in XRL. Architectures to facilitate inter-operation through loose and tight integration are also discussed. Examples illustrate how this approach can be used for implementing interorganizational electronic commerce applications. As a proof of concept we have also developed XRL/flower, a prototype implementation of a workflow management system based on XRL. Introduction With the rapid expansion seen in electronic commerce 1 , there is a major need for infrastructures and frameworks that can be used to implement inter-organizational applications. In particular it is essential to provide support for routing of documents across organizations in a standardized and yet flexible manner to enable open electronic commerce [18, 19, 26, 27, 33, 36, 53] . Developing more homogeneous languages for various electronic commerce activities [21] is one way to facilitate increased productivity and interoperability. In this paper, we describe an architecture and a language called XRL (eXchangeable Routing Language) that provide support for routing of workflow among trading partners for Internetbased electronic commerce services. 1 In 1998, about $ 43 billion worth of business was done over the Web. This volume was projected to increase to $1.3 Trillion by 2003. 2 Current workflow products are generally intra-organizational and based on centralized architectures. Therefore, they typically lack scalability and are also not very useful for implementing interorganizational applications [1, 4, 5, 6, 36] . Moreover, these systems use propriety languages for specifying workflow processes. Despite efforts by the Workflow Management Coalition (WfMC, [30]), a lingua franca for workflow management is lacking. The Workflow Process Definition Language (WPDL) of the WfMC has no formal semantics, i.e., the dynamics of many of its constructs are ill-defined, and most systems only support a subset of WPDL. The standard proposed by the WfMC for interoperability among different workflow systems (Wf-XML [50]) is based on WPDL and traditional centralized architectures. Such an approach does not address some of the fundamental problems related to cross-organizational, highly-dynamic workflows. The only way to support such workflows is for each organization to have a common understanding for the workflow processes at hand. Therefore, we propose a new language which enables the easy and unambiguous exchange of process information, i.e., a lingua franca for crossorganizational workflow. An inter-organizational workflow involves communication between two (or more) parties with different information systems. Although various suppliers of products and services, such as Dell, Federal Express, etc., already make order tracking information available on their web sites, the next level of customer support will allow customers to perform more detailed order status inquiries, and to make changes dynamically to their orders (e.g., "change the cd-rom in my laptop order to a DVD"). For instance, a customer should be able to find out why his or her order is delayed, and what are possible alternatives for expediting it (perhaps, the delayed component or feature is not so important and can be omitted, or a substitute can be used, etc.). Process information is also very useful because it encapsulates the business rules of an organization. For instance, one supplier may expect to receive payment after delivery, while another may have the opposite policy. Therefore, a customer who deals with both suppliers, and does not pay careful attention to these rules, may be held up waiting for the shipments to arrive not realizing that the payment has not been made in one case. Currently, such misunderstandings are prevented by paying careful attention to business rules of organizations, which are available in hardcopy form. Often considerable manual interaction between personnel of the buyer and supplier organizations is required to parse and understand these rules. This is time consuming and expensive, and incurs delays, especially in setting up new arrangements between two partners. We anticipate that friction-less e-commerce will only be possible if such arrangements can be established on the fly, in an automated manner. This requires that each partner make its processes (at least, selectively) transparent to its other partners (e.g., the process schema would show whether payment occurs prior to, or after, delivery). Inter-organizational workflows are problematic because the process information of each partner is hidden from other partners, and there is no easy or common way of describing such information. While the
doi:10.1287/isre. fatcat:cg75qfy44jf4tjuo4oxysy2xh4