Jerzy Letkowski

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There is rapidly growing momentum for web enabled agents that reason about and dynamically integrate the appropriate knowledge and services at run-time. The World Wide Web Consortium and the DARPA Agent Markup Language (DAML) program have been actively involved in furthering this trend. The dynamic integration of knowledge and services depends on the(More)
Situation awareness involves the identification and monitoring of relationships among level-one objects. This problem in general is intractable (i.e., there is a potentially infinite number of relations that could be tracked) and thus requires additional constraints and guidance defined by the user if there is to be any hope of creating practical situation(More)
There is rapidly growing momentum for web enabled agents that reason about and dynamically integrate the appropriate knowledge and services at run-time. The dynamic integration of knowledge and services depends on the existence of explicit declarative semantic models (ontologies). We have been building tools for ontology development based on the Unified(More)
When developing situation awareness applications we begin by constructing an OWL ontology to capture a language of discourse for the domain of interest. Such an ontology, however, is never sufficient for fully representing the complex knowledge needed to identify what is happening in an evolving situation – this usually requires general implication afforded(More)
Situation awareness means simply that one knows what is going on around oneself. In operational terms, this means that one knows the information that is relevant to a task. Maintaining a coherent awareness of the situation is essential to successful task completion. We propose a formal basis for situation awareness that draws on sources and makes use of(More)
Situation awareness involves the identification and monitoring of relationships among objects participating in an evolving situation. This problem in general is intractable (i.e., there is a potentially infinite number of relations that could be tracked) and thus requires additional constraints and guidance defined by the user if there is to be any hope of(More)
Situation Awareness involves the comprehension of the state of a collection of objects in an evolving environment. This not only includes an understanding of the objects’ characteristics but also an awareness of the significant relations that hold among the objects at any point in time. Systems for establishing situation awareness require a knowledge(More)
As the use of Semantic Web ontologies continues to expand there is a growing need for tools that can validate ontological consistency and provide guidance in the correction of detected defects and errors. A number of tools already exist as evidenced by the ten systems participating in the W3C’s evaluation of the OWL Test Cases. For the most part, these(More)
Ontologies are becoming increasingly popular due to recent efforts to extend the capabilities of the World Wide Web through the addition of formal semantics. While ontologies have traditionally been used as precise languages to facilitate efficient exchange of information among people, the “Semantic Web” is extending this role to software agents. For this(More)
We say that a computer program augments the analyst if it can infer facts that are implicit in existing information, but that may be relatively difficult for a human to infer. Among a multitude of reasons, the analyst's task is difficult because (1) reported information to be analyzed and reasoned about often cannot be completely trusted (requiring(More)