The contract net protocol (CNP) serves as a framework for cooperative distributed problem-solving agents to allocate tasks among themselves. Multi-agent systems (MAS) based on CNP are, however, susceptible to message congestion which hampers the efficiency of agents in making their task allocation decisions. Various attempts have been made to alleviate the problem. This article focuses on a particular solution, namely, audience restriction (AR). While AR has been incorporated into several CNP-based MAS, there is a lack of empirical evidence on its effectiveness in reducing message congestion and whether its contribution could be outweighed by its overheads. Furthermore, AR has a direct impact on the participation rate of agents in making task allocation decisions which has not been properly considered. By comparing the performance of a CNP-based task allocation algorithm with its AR variants in a simulation study in manufacturing control, our results show that, while AR can effectively be applied to reduce message traffic under heavy load conditions, there is also evidence that if audience size is only marginally reduced, message traffic can increase as well as decrease. The new findings contribute to more efficient CNP-based manufacturing control algorithms.
|Number of pages||13|
|Journal||International Journal of Computer Integrated Manufacturing|
|Early online date||12 Jul 2018|
|Publication status||Published - 3 Oct 2018|
Bibliographical noteThis work was supported by the Lingnan University Direct Research Grant under Grant DR14A7.
- discrete event simulation
- dynamic scheduling
- Manufacturing control systems
- multi-agent systems
- shop-floor control