1,721,033 research outputs found
Knowledge acquisition for search and rescue planning
No full textThere is an increasing adoption of knowledge-level modelling within expert system development. However, it has had less impact in the generic areas of planning, scheduling and resource allocation. In this paper, we outline the development of a knowledge-level modelling approach within the domain of planning for search and rescue (SAR). Existing problem solving models for planning are almost exclusively derived from an analysis of the functional architectures of classic AI planners such as TWEAK and NONLIN. We argue that this makes their suitability for directly assisting knowledge acquisition questionable. Our approach makes a clear distinction between domain-derived knowledge-level models and those derived from computational architectures. We describe how the combination of these two types of models can achieve clear benefits within the course of KBS development. The paper includes extensive descriptions of the SAR domain, which illustrate the practical knowledge engineering problems that our approach attempts to address
A model of activity-dependent anatomical inhibitory plasticity applied to the mammalian auditory system
No full textWe construct a model of activity-dependent, anatomical inhibitory plasticity. We apply the model to the mammalian auditory system. Specifically, we model the activity-dependent topographic refinement of inhibitory projections in the auditory brain stem, and we construct an anatomically abstract model of binaural band formation in the primary auditory cortex involving the segregation of different populations of inhibitory and excitatory afferents. Issues raised and predictions made include the nature of interactions between excitatory and inhibitory afferents innervating the same population of target cells, and the possibility that pharmacological manipulations of the developing primary auditory cortex might induce a shift in the periodicity of binaural bands. Any model of inhibitory plasticity must confront the issue of postulating mechanisms underlying such plasticity. In order to attempt to understand, at least theoretically, what the mechanisms underlying inhibitory plasticity might be, we propose the existence of a new class of neurotrophic factors that promote neurite outgrowth from and mediate competitive interactions between inhibitory afferents. We suppose that such factors are up-regulated by hyperpolarisation and down-regulated by depolarisation. Furthermore, we suppose that their activity-dependent release from target cells depends on Cl- influx. Such factors are therefore assumed to be the physiological inverse of such factors as nerve growth factor and brain-derived neurotrophic factor, which are up-regulated by depolarisation and down-regulated by hyperpolarisation, with their activity-dependent release depending on Na+, and not Ca2+, influx
Exploiting semantics for e-science on the semantic grid
No full textIn this paper we address the problem of exploiting semantics for e-Science [1] in the emerging future e-Science infrastructure - the Semantic Grid [2]. The discussion is taken in the context of Grid enabled optimisation and design search in engineering (“Geodise” project) [3]. In our work we have developed a semantics based Grid-enabled computing architecture for Geodise. The architecture has incorporated a service-oriented distributed knowledge management framework for providing semantic and knowledge support. It uses ontologies as the conceptual backbone for information level and knowledge-level computation. Geodise resources including computational codes, capabilities and knowledge are semantically enriched using ontologies through annotations, thus facilitating seamless access, flexible interoperation and resource sharing on the Grid. We describe ontological engineering work and various approaches to semantic enrichment in Geodise. The semantically enriched content together with the Semantic Grid paradigm have been used as the foundation for the development of an ontology-enabled Geodise problem solving environment prototype (PSE). We have partially implemented the workflow construction environment in
the Geodise PSE in which semantics is exploited to describe, discover and compose engineering computation resources for engineering problem-solving
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