Papers and Publications, Center of Excellence in Command, Control, Communications, and Intelligence
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This collection contains papers written by members and fellows of the C4I Center.
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Browsing Papers and Publications, Center of Excellence in Command, Control, Communications, and Intelligence by Subject "Behavioral model"
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Item Bayesian ontologies in AI systems(2006-07-30T03:10:44Z) Costa, Paulo C. G.; Laskey, Kathryn B.; AlGhamdi, GhaziOntologies have become ubiquitous in current-generation information systems. An ontology is an explicit, formal representation of the entities and relationships that can exist in a domain of application. Following a well-trodden path, initial research in computational ontology has neglected uncertainty, developing almost exclusively within the framework of classical logic. As appreciation grows of the limitations of ontology formalisms that cannot represent uncertainty, the demand from user communities increases for ontology formalisms with the power to express uncertainty. Support for uncertainty is essential for interoperability, knowledge sharing, and knowledge reuse. Bayesian ontologies are used to describe knowledge about a domain with its associated uncertainty in a principled, structured, sharable, and machine-understandable way. This paper considers Multi-Entity Bayesian Networks (MEBN) as a logical basis for Bayesian ontologies, and describes PR-OWL, a MEBN-based probabilistic extension to the ontology language OWL. To illustrate the potentialities of Bayesian probabilistic ontologies in the development of AI systems, we present a case study in information security, in which ontology development played a key role.Item Detecting Threatening Behavior Using Bayesian Networks(2006-03-06T15:11:39Z) AlGhamdi, Ghazi; Laskey, Kathryn B.; Wang, Xun; Barbará, Daniel; Shackelford, Thomas; Wright, Edward J.; Fitzgerald, JulieThis paper presents an innovative use of human behavior models for detecting insider threats to information systems. While most work in information security concerns detecting and responding to intruders, violations of system security policy by authorized computer users present a major threat to information security. A promising approach to detection and response is to model behavior of normal users and threats, and apply sophisticated inference methods to detect patterns of behavior that deviate from normal behavior in ways suggesting a possible security threat. This paper presents an approach, based on multi-entity Bayesian networks, to modeling user queries and detecting situations in which users in sensitive positions may be accessing documents outside their assigned areas of responsibility. Such unusual access patterns might be characteristic of users attempting illegal activities such as disclosure of classified information. We present a scalable proof of concept behavior model, provide an experimental demonstration of its ability to detect unusual access patterns in simulated situations, and describe future plans to increase the realism and fidelity of the model.