Abstract-Repairing an inconsistent knowledge base is a wellknown problem for which several solutions have been proposed and implemented in the past. In this paper, we start by looking at databases with active integrity constraints -consistency requirements that also indicate how the database should be updated when they are not met -as introduced by Caroprese et al. We show that the different kinds of repairs considered by those authors can be effectively computed by searching for leaves of specific kinds of trees. Although these computations are in general not very efficient (deciding the existence of a repair for a given database with active integrity constraints is N P -complete), on average the algorithms we present make significant reductions on the number of nodes in the search tree. Finally, these algorithms also give an operational characterization of different kinds of repairs that can be used when we extend the concept of active integrity constraints to the more general setting of knowledge bases.
In the design of resource bounded agents, high-level cognitive activities, such as reasoning, raise important problems related both to the adaptive ability and to the computational complexity of the underlying cognitive processes. To address these problems, we adopt an agent model where emotion and cognition are conceived as two integrated aspects of intelligent behavior and we present affective-emotional mechanisms that support the adaptation to changing environments and a controlled use of resources. These mechanisms produce an attention field that constrains the input to reasoning processes and also regulate the activation period of those processes. Experimental results are presented to illustrate this approach and to evaluate it by comparison with reference results concerning intention reconsideration policies.
Abstract. Multi-context systems (MCSs) are an important framework for heterogeneous combinations of systems within the Semantic Web. In this paper, we propose generic constructions to achieve specific forms of interaction in a principled way, and systematize some useful techniques to work with ontologies within an MCS. All these mechanisms are presented in the form of general-purpose design patterns. Their study also suggests new ways in which this framework can be further extended.
Abstract. We introduce a formalism to couple integrity constraints over general-purpose knowledge bases with actions that can be executed to restore consistency. This formalism generalizes active integrity constraints over databases. In the more general setting of multi-context systems, adding repair suggestions to integrity constraints allows defining simple iterative algorithms to find all possible grounded repairs -repairs for the global system that follow the suggestions given by the actions in the individual rules. We apply our methodology to ontologies, and show that it can express most relevant types of integrity constraints in this domain.
A new model is imroduced for describing societies of communicating knowledge systems from an artificial intelligence perspective. The society is defined as a Time-evolving concept containing both static and dynamic knowledge. The static knowledge includes The components of The society, namely The actor Types, The communication issue Types, and The behavior pattern Types. The dynamic knowledge specifies how The society can evolve. Each component is a metatheory described using a specific representation system. The metatheories representing The actor Types include self-knowledge, knowledge about other actors, and knowledge about The real world. The communication issues always reflect The knowledge ofThe sending actor and produce some effect on The receiving actor.for instance. enrichments ofits knowledge or conflicts with' iTS own knowledge. Conflias are oftwo forms: routine conflicts TO be solved by mediating actors wiTh no inre/ligenr knowledge. or conflicts that require intelligent knowledgeand That must be solved by special aaors called managers. Behavior pattern rules are Theories that express cause-effect rules regarding The society behavior as a whole. Technically, modifications of The society are defined as parameterized Theories whose argument specifies The requirements To be satisfied before a change of the situation and whose body introduces The modifications TO be performed.
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