Engineering Agent-Based E-Commerce Systems Using The Semiotic Approach And The DEMO Transaction Concept Joseph Barjis Department of Information Systems & Software Engineering, Delft University of Technology The Netherlands; e-mail: J.Barjis@its.tudelft.nl; http://is.twi.tudelft.nl/~Barjis Samuel Chong School of Computing, Staffordshire University, Stafford, Beaconside, ST18 0AB, England, UK e-mail: Y.C.Chong@staffs.ac.uk; http://www.soc.staffs.ac.uk/~cmrycc Jan L.G. Dietz Department of Information Systems & Software Engineering, Delft University of Technology The Netherlands; e-mail: J.L.G.Dietz@is.twi.tudelft.nl Kecheng Liu School of Computing, Staffordshire University, Stafford, Beaconside, ST18 0AB, England, UK e-mail: K.Liu@staffs.ac.uk; http://www.soc.staffs.ac.uk/~cmtkl ABSTRACT As software agents get more sophisticated, it becomes difficult to understand and model such systems. In this paper, we contend that all developers bring to the task of development some implicit or explicit assumptions of the agent communication pattern. This issue is not readily addressed in current literature and represents a gap in knowledge. For this purpose a generic pattern of inter-agent communication is introduced and discussed in this paper. For better understanding and modelling of agent-based e-commerce systems, the semiotic approach and the DEMO transaction concept are briefly introduced. It is shown that the semiotic approach offers a unifying framework for identifying the roles of agents, the responsible human agents and the right/constraints associated with each role. The DEMO transaction concept is applied to model the communicative interaction between agents. Keywords: Software agent and agents’ communication, Semiotics, DEMO methodology 1. Introduction Electronic commerce is emerging as one of the most exciting research areas in our era. E-commerce systems are dynamic networks of interrelated transaction processes between two or more trading agents. Agent-based technology is emerging as a powerful paradigm for developing e-commerce systems. In recent years, software agents have been introduced to e-commerce. Software agents in e-commerce systems have some autonomy and the ability to sense and react to their environment, as well as socially communicate