I - 379 USING ROLES TO SPECIFY BUSINESS OBJECT COLLABORATIONS Artur Caetano *† António Rito Silva *‡ José Tribolet *† *Department of Information Systems and Computer Science, Instituto Superior Técnico, Technical University of Lisbon. † Center for Organizational Engineering (CEO), INOV, INESC Inovação. ‡ Software Engineering Group, INESC-ID. Surface Mail Address: INESC, Rua Alves Redol 9, 1000-029 Lisboa, Portugal. ABSTRACT Role-based business process modeling deals with separating the universe of process modeling into different areas of concern by describing how business objects relate to each other during collaborations. A business object represents a concept of interest within the organization, such as an activity or an actor. Business objects play multiple roles according to their behavior while collaborating with other business objects. Collaborations can then be expressed by the roles played by every participant in that scenario. This allows, on the one hand, creating semantically richer business process models, and, on the other, designing business objects where behavior is clearly separated and dependent on its usage context. Both of these results contribute in increasing the understandability of process models and business object reuse. KEYWORDS Business Process Modeling, Role Modeling, Object-Oriented Analysis and Design, UML, Organizational Engineering. 1. INTRODUCTION Organizational modeling deals with providing an enterprise-wide view of an organization from where decisions can be made. Business process modeling specializes on describing how activities interact and relate with other organizational entities while supporting the operation of the business. The modeling and representation of the knowledge about an organization and its processes has been the focus of specific research in past years and significant work has been done on developing business process modeling concepts, methodologies and ontologies as well as on the specification of process modeling languages (Madhavji 1991, Miers 1994, Eriksson 2001, Leymann 2002). Business process modeling can also be used for multiple purposes, such as facilitating human understanding and communication (Walford 1999), supporting process improvement and re-engineering through business process analysis and simulation (Eertink 1999, McGowan 1993), automating the execution of business processes (Aalst 2002, Scheer 1999) and facilitating coordinated business and system development by creating and keeping the alignment between business processes and their support systems (Chan 2002). Modeling business processes involves capturing the structure of the multiple business objects, their relationships and collaborations. A business object represents a concept of interest in the organization, such as activities or human or automated actors. Identifying the business objects of an organization is fundamental to help documenting and evolving the business by facilitating communication and analysis. Additionally, if an organization holds a documented view on its business objects and their network of relationships this may foster business object reuse across different organizational process units. However, properly identifying and modeling the business objects of an organization is not a straightforward task, especially when reuse is a concern. For instance, business objects are used by multiple activities in different business contexts and processes. On the one hand, in a real organization, every business