Efficient Source Discovery and Service Composition for Ubiquitous Computing Environments

To be truly pervasive the devices in a ubiquitous computing environment have to be able to form a “coalition” without human intervention. The Semantic Web provides the infrastructure for discovery and composition of device functionalities. AI planning has been a popular technology for automatic service discovery and composition in the Semantic Web. However, because the Web is so vast and changes so rapidly, a planning agent cannot make a closed-world assumption. This condition makes it difficult for an agent to know when it has gathered all relevant information or when additional searches may be redundant. To avoid redundancy we incorporate Local Closed World reasoning with HTN planning to compose Semantic Web services. In addition, when performing information gathering tasks on the Semantic Web, we use Local Closed World reasoning and a concept of “source relevance” to control the search process. We also describe a prototype agent that we have developed.