NPL: Negotiation Pattern Language - A Design Pattern Language for Decentralized Coordination and Negotiation Protocols

Currently negotiation covers a huge and unstructured domain of negotiationand coordination protocols1 and associated strategies. Researchers and practitioners like system engineers have almost no support in discussing protocol solutions to frequently occurring negotiation problems and in designing and implementing successful protocols and associated negotiation media. Negotiation engineering remains a laborious trial and error process. We propose a novel approach to the description of negotiation and coordination protocols that is based on the idea of design patterns. Design patterns have been used successfully in recent years in the software engineering community in order to share knowledge about the structural and behavioural properties of software and to communicate object-oriented design solutions [1, 2]. In this article we introduce a descriptive, semi-formal design pattern language for negotiation and decentralized coordination protocol solutions. The Negotiation Pattern Language (NPL) uses a combination of narrative human readable descriptions, formal models like Role Activity Diagrams (RAD) and machine-processable XML mark-up. This underpins tool-based cataloguing and publishing of patterns in a machine-readable, semi-formal pattern definition language and supports engineers to understand and apply these patterns. We have collected and described a first set of well-known and successful negotiation and coordination protocols and published them in a web based Design Pattern Library (DPL). The patterns are written from the point of view of a system engineer, but draw on the results of other disciplines such as social choice theory, mechanism design theory or group decision and negotiation theory. This should initiate a community effort, whereas the DPL might be used to gather and share knowledge about protocol designs. We contribute to an interdisciplinary and efficient communication process about design solutions for various negotiation and coordination problems and support system engineers in their design decisions.