Reactive Mobility by Failure: When Fail Means Move

Mobile agent development is mainly supported by Java-based platforms and tools. However, the weak mobility model they use, the lack of adequate support for developing inference and reasoning mechanisms, added to the inherent complexity of building location-aware software, impose strong limitations for developing mobile intelligent agent systems. In this article we present MoviLog, a platform for building Prolog-based mobile agents with a strong mobility model. MoviLog is an extension of JavaLog, an integration of Java and Prolog, that allows us to take advantage of the best features of the programming paradigms they represent. MoviLog agents, called Brainlets, are able to migrate among different Web sites, either proactively or reactively, to use the available knowledge in order to find a solution. The major contribution of MoviLog is its Reactive Mobility by Failure (RMF) mechanism. RMF is a mechanism that acts when an agent needs a resource or service that is not available at the current executing site. RMF uses a distributed multi-agent system to transparently transport the executing agent to the site where the resource/service is available, thus reducing the development effort with respect to the traditional mobile agent approach, while maintaining its advantages.