The huge number of autonomousand heterogeneous data repositories accessible on the “global information infrastructure” makes it impossible for users to be aware of the locations, structure/organization, query languages and semantics of the data in various repositories. There is a critical need to complement current browsing, navigationaland informationretrieval techniques with a strategy that focuses on information content and semantics. In any strategy that focuses on information content, the most critical problem is that of different vocabularies used to describe similar information across domains. We discuss a scalable approach for vocabulary sharing. The objects in the repositories are represented as intensional descriptions by pre-existing ontologies expressed in Description Logics characterizing information in different domains. User queries are rewritten by using interontologyrelationships to obtain semanticspreserving translations across the ontologies. 1.

Most databases contain "name constants" like course numbers, personal names, and place names that correspond to entities in the real world. Previous work in integration of heterogeneous databases has assumed that local name constants can be mapped into an appropriate global domain by normalization. However, in many cases, this assumption does not hold; determining if two name constants should be considered identical can require detailed knowledge of the world, the purpose of the user's query, or both. In this paper, we reject the assumption that global domains can be easily constructed, and assume instead that the names are given in natural language text. We then propose a logic called WHIRL which reasons explicitly about the similarity of local names, as measured using the vector-space model commonly adopted in statistical information retrieval. We describe an efficient implementation of WHIRL and evaluate it experimentally on data extracted from the World Wide Web. We show that WHIR...

this article--- suggest a paradigm for software development that emphasizes autonomy both at design time and runtime, adaptivity, and cooperation. This approach seems appealing in a world of distributed, heterogeneous systems. Languages for communicating agents promise to play the role that natural languages played for their human counterparts. An agent communication language that allows agents to interact while hiding the details of their internal workings will result in agent communities that tackle problems no individual agent could.

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Concepts in differentiated ontologies inherit definitional structure from concepts in shared ontologies. Shared, inherited structure provides a common ground that supports measures of “description compatibility. ” These algorithms are the primary contribution of this paper. The description-compatibility measures compare concepts to predict semantic compatibility, the probability that an instance of a recommendation will satisfy a request. The description-compatibility measures cross a spectrum regarding their knowledge of the semantics of roles in concept definitions. Some of the measures identify and analyze correspondences among elements of the definitions, and are thus a form of analogical reasoning. We use simulations to evaluate the description-compatibility measures in detail. Description compatibility can be used to rank alternative query translations, and to guide search for capabilities across communities that subscribe to differentiated ontologies. 1.

In this paper, we give an overview of a system (CAIMAN) that can facilitate the exchange of relevant documents between geographically dispersed people in Communities of Interest. The nature of Communities of Interest prevents the creation and enforcement of a common organizational scheme for documents, to which all community members adhere. Each community member organizes her documents according to her own categorization scheme (ontology). CAIMAN exploits this personal ontology, which is essentially the perspective of a user on a domain, for information retrieval. Related documents are retrieved on a concept granularity level from a central community document repository. To find the related concepts in the queried ontology, CAIMAN performs an ontology mapping. The ontology mapping in CAIMAN is based on a novel approach, which considers the concepts in an ontology implicitly represented by the documents assigned to each concept. Using machine learning techniques for te...

This paper addresses issues in developing open multiagent systems, in which it is easy to expand the functionality by adding new agents with new capabilities, and which facilitate interoperability with other agent systems. We argue that an open multiagent system should define the following support elements for agent communication: 1. A common set of speech acts to define the types of messages that an agent might send to another agent. 2. A common service ontology by which the agents can describe their capabilities to each other, and reason about which agents have the capabilities needed to execute specific tasks. 3. A common set of prescriptive conversation policies to define the acceptable exchanges of messages between agents. In addition to the above, we also discuss the utility of having a matchmaking agent that can reason over agent capabilities to recommend agents for specific tasks, where the capabilities and requirements are defined using a common service ontolog...

Despite the substantial number of multi-agent systems that use an Agent Communication Language (ACL) the dust has not settled yet over the landscape of ACLs. The semantic specification issues have monopolized the debate at the expense of other important pragmatic issues that must be adequately resolved in the immediate future if ACLs are going to support the development of robust agent systems. After introducing some of the basic concepts relating to Agent Communication Languages, we cover KQML and FIPA ACL, the two existing fully-specified ACLs. We give a brief introduction to their semantics and the issues relating to semantic descriptions of ACLs. We then shift our focus beyond the semantics and point to problems and limitations shared by both ACLs. Questions such as the nature of conformance of an agent system with an ACL specification and issues such as naming, registration, authentication, basic facilitation services, etc., may or may not be (technically speaking) part of an ACL ...

Activities such as Web Services and the Semantic Web are working to create a distributed web of machine understandable data. We address three important problems that need to be solved to realize this vision. We discuss the problem of scalable and deployable query systems and present a simple, but general query interface called GetData. We address the issue of creating global agreements on vocabularies and introduce the concept of Semantic Negotiation, a process by which two programs can bootstrap from small shared vocabularies to larger shared vocabularies. We discuss the problem of programs determining which data sources to trust and present a solution that uses a Web of Trust between Semantic Web registries. We briefly describe TAP, a system that implements the GetData interface, Semantic Negotiation and Web of Trust enabled registries. We then introduce an application of the Semantic Web called Semantic Search and describe an implemented system which uses the data from the Semantic Web to improve traditional search results.

InfoSleuth is an agent-based system that can be configured to perform many di#erent information management activities in a distributed environment. InfoSleuth TM agents provide a number of complex query services that require resolving ontology-based queries over dynamically changing, distributed, heterogeneous resources. These include distributed query processing, locationindependent single-resource updates, event and information monitoring, statistical or inferential data analysis, and trend discovery in complex event streams. It has been used in numerous applications, including the Environmental Data Exchange Network and the Competitive Intelligence System. Keywords: Multi-agent systems, agent-based systems, information agents, heterogeneous data, query processing, information subscription. 1. Introduction In the past 15-20 years, numerous products and prototypes have regularly appeared to provide uniform access to heterogeneous data sources. As a result, that access to...