| 1. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
-
A Causal Perspective to Qualitative Spatial Reasoning in the Situation Calculus
- 2006
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Ingår i: Advances in Artificial Intelligence - IBERAMIA-SBIA 2006. - Berlin, Heidelberg : Springer. - 9783540454625 - 9783540454649 ; , s. 430-440
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Konferensbidrag (refereegranskat)abstract
- We propose the utilisation of a general formalism to reason about action & change for reasoning about the dynamic purpose-directed aspects of spatial change. Such an approach is necessary toward the general integration of qualitative spatial reasoning with reasoning about the teleological aspects of spatial change. With this as the overall context, the main contribution of this paper is to illustrate first ideas relevant to providing a causal perspective to qualitative spatial reasoning using the situation calculus. With minimal notions about space & spatial dynamics, we perform a naive characterisation of objects based on their physical properties and investigate the key representational aspects of a topological theory of space, namely the region connection calculus, in the situation calculus. Further, ontological distinctions are made between various occurrents, i.e., actions and internal & external events, and a domain level characterisation of spatial occurrents in terms of their spatial pre-conditions & effects is performed so as to provide a causal perspective to spatial reasoning.
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| 2. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
-
A General Framework Based on Dynamic Constraints for the Enrichment of a Topological Theory of Spatial Simulation
- 2005
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Ingår i: Knowledge-Based Intelligent Information and Engineering Systems. - Berlin, Heidelberg : Springer. - 9783540288978 - 9783540319979 ; , s. 366-373
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Konferensbidrag (refereegranskat)abstract
- Qualitative spatial representation and reasoning has emerged as a major sub-field of AI in the past decade. An important research problem within the field is that of integrated reasoning about various spatial aspects such as distance, size, topology etc - an important application here being the qualitative simulation of physical processes. Approaches based on topology alone fail to provide an explicit account of other important aspects of spatial change thereby also not utilizing dynamically available information pertaining to them. Our work in this paper is based on the idea that a general theory of spatial simulation based on topological changes alone can be enriched by the inclusion of sub-theories relevant to other aspects of spatial change. We propose a general framework consisting of dynamic constraints for the enrichment of a topological theory of spatial changes. We propose the utilisation of such dynamic constraints for the incorporation of dynamically available information relevant to various aspects of space thereby making that aspect explicit in the theory. As an example of the proposed approach, we integrate dynamically available information pertaining to motion and size with the topological theory of RCC-8 using our framework of dynamic constraints.
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| 3. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
-
A Qualitative Model of Dynamic Scene Analysis and Interpretation in Ambient Intelligence Systems
- 2009
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Ingår i: International Journal of Robotics and Automation. - : ACTA Press. - 0826-8185 .- 1925-7090. ; 24:3, s. 235-244
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Tidskriftsartikel (refereegranskat)abstract
- Ambient intelligence environments necessitate representing and reasoning about dynamic spatial scenes and configurations. The ability to perform predictive and explanatory analyses of spatial scenes is crucial towards serving a useful intelligent function within such environments. We present a formal qualitative model that combines existing qualitative theories about space with it formal logic-based calculus suited to modelling dynamic environments, or reasoning about action and change in general. With this approach, it is possible to represent and reason about arbitrary dynamic spatial environments within a unified framework. We clarify and elaborate on our ideas with examples grounded in a smart environment.
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| 4. |
- Bhatt, Mehul, Professor, 1980-
(författare)
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Dynamical Spatial Systems - A Potential Approach for the Application of Qualitative Spatial Calculi
- 2008
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Ingår i: Proceedings of the Twenty-First International Florida Artificial Intelligence Research Society Conference, May 15-17, 2008, Coconut Grove, Florida, USA. - Menlo Park : AAAI Press. - 9781577353652 ; , s. 580-585
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Konferensbidrag (refereegranskat)abstract
- A dynamical systems approach for modeling changing spatial environments is formalised. The formalisation adheres to the representational and computational semantics of situation calculus and includes a systematic account of all aspects necessary to implement a domain-independent qualitative spatial theory that is applicable across diverse application areas. Foundational to the formalisation is a situation calculus based causal theory and a generalised view of qualitative spatial calculi that encompass one or more spatial domains. Furthermore, aspects considered inherent to dynamic spatial systems are also accounted for and the relevant computational tasks addressed by the proposed formalisation are stated explicitly.
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| 5. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
-
Modelling Dynamic Spatial Systems in the Situation Calculus
- 2008
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Ingår i: Spatial Cognition and Computation. - : Taylor & Francis Group. - 1387-5868 .- 1573-9252 .- 1542-7633. ; 8:1-2, s. 86-130
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Tidskriftsartikel (refereegranskat)abstract
- We propose and systematically formalise a dynamical spatial systems approach for the modelling of changing spatial environments. The formalisation adheres to the semantics of the situation calculus and includes a systematic account of key aspects that are necessary to realize a domain-independent qualitative spatial theory that may be utilised across diverse application domains. The spatial theory is primarily derivable from the all-pervasive generic notion of "qualitative spatial calculi" that are representative of differing aspects of space. In addition, the theory also includes aspects, both ontological and phenomenal in nature, that are considered inherent in dynamic spatial systems. Foundational to the formalisation is a causal theory that adheres to the representational and computational semantics of the situation calculus. This foundational theory provides the necessary (general) mechanism required to represent and reason about changing spatial environments and also includes an account of the key fundamental epistemological issues concerning the frame and the ramification problems that arise whilst modelling change within such domains. The main advantage of the proposed approach is that based on the structure and semantics of the proposed framework, fundamental reasoning tasks such as projection and explanation directly follow. Within the specialised spatial reasoning domain, these translate to spatial planning/re-configuration, causal explanation and spatial simulation. Our approach is based on the hypothesis that alternate formalisations of existing qualitative spatial calculi using high-level tools such as the situation calculus are essential for their utilisation in diverse application domains such as intelligent systems, cognitive robotics and event-based GIS.
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| 6. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
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MOVE : A Distributed Framework for Materialized Ontology View Extraction
- 2006
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Ingår i: Algorithmica. - : Springer. - 0178-4617 .- 1432-0541. ; 45:3, s. 457-481
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Tidskriftsartikel (refereegranskat)abstract
- The use of ontologies lies at the very heart of the newly emerging era of semantic web. Ontologies provide a shared conceptualization of some domain that may be communicated between people and application systems. As information on the web increases significantly in size, web ontologies also tend to grow bigger, to such an extent that they become too large to be used in their entirety by any single application. Moreover, because of the size of the original ontology, the process of repeatedly iterating the millions of nodes and relationships to form an optimized sub-ontology becomes very computationally extensive. Therefore, it is imperative that parallel and distributed computing techniques be utilized to implement the extraction process. These problems have stimulated our work in the area of sub-ontology extraction where each user may extract optimized sub-ontologies from an existing base ontology. The extraction process consists of a number of independent optimization schemes that cover various aspects of the optimization process, such as ensuring consistency of the user-specified requirements for the sub-ontology, ensuring semantic completeness of the sub-ontology, etc. Sub-ontologies are valid independent ontologies, known as materialized ontologies, that are specifically extracted to meet certain needs. Our proposed and implemented framework for the extraction process, referred to as Materialized Ontology View Extractor (MOVE), has addressed this problem by proposing a distributed architecture for the extraction/optimization of a sub-ontology from a large-scale base ontology. We utilize coarse-grained data-level parallelism inherent in the problem domain. Such an architecture serves two purposes: (a) facilitates the utilization of a cluster environment typical in business organizations, which is in line with our envisaged application of the proposed system, and (b) enhances the performance of the computationally extensive extraction process when dealing with massively sized realistic ontologies. As ontologies are currently widely used, our proposed approach for distributed ontology extraction will play an important role in improving the efficiency of ontology-based information retrieval.
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| 7. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
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Ontology driven semantic profiling and retrieval in medical information systems
- 2009
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Ingår i: Journal of Web Semantics. - : Elsevier. - 1570-8268 .- 1873-7749. ; 7:4, s. 317-331
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Tidskriftsartikel (refereegranskat)abstract
- We propose the application of a novel sub-ontology extraction methodology for achieving interoperability and improving the semantic validity of information retrieval in the medical information systems (MIS) domain. The system offers advanced pro. ling of a user's field of specialization by exploiting the concept of sub-ontology extraction, i.e., each sub-ontology may subsequently represent a particular user pro. le. Semantic pro. ling of a user's field of specialization or interest is necessary functionality in any medical domain information retrieval system; this is because the (structural and semantic) extent of information sources is massive and individual users are only likely to be interested in specific parts of the overall knowledge documents on the basis of their area of specialization. The prototypical system, OntoMOVE, has been specifically designed for application in the medical information systems domain. OntoMOVE utilizes semantic web standards like RDF(S) and OWL in addition to medical domain standards and vocabularies encompassed by the UMLS knowledge sources.
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| 8. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
-
OntoMove : A Knowledge Based Framework for Semantic Requirement Profiling and Resource Acquisition
- 2007
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Ingår i: Proceedings of the 2007 Australian Software Engineering Conference (ASWEC'07). - : IEEE Computer Society. - 9780769527789 - 0769527787 ; , s. 137-146
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Konferensbidrag (refereegranskat)abstract
- The use of formal knowledge representation structures, or ontologies, has found immense applicability for the interoperability of software systems, e.g., alignment of software and business process models. Toward the management of such knowledge structures, an important foundational problem is that of ontology reuse - it is uncommon for new applications or for different components within one application to use an already available ontology in its entirety. Depending on component specific requirements, typical re-usages are restricted to refined versions of an existing ontology, with the refinement taking the form of a contraction of the knowledge contained therein. Furthermore, when the ontology is used to ascribe meaning to independently existing 'resources' (e.g., documents collections, source code, software manuals, process template repositories) by way of meta-data, there exists a direct mapping between different views/re-uses of an ontology and their respective semantic scopes within an annotated resource repository thereby leading to the concept of view/reuse dependent resource retrieval. We implement a framework that supports ontology reuse by way of a requirement driven sub-ontology extraction methodology. Additionally, based on this concept of a sub-ontology, we implement the idea of a user/component 'requirement profile' consisting of semantic descriptions of the user's interest within a 'resource repository' that has been annotated with semantic types from the ontology under consideration. A generic framework that implements these ideas and its application in the domains of Medical Information Retrieval systems and Business Process Management Systems (BPMS) is presented.
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| 9. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
-
Qualitative Spatial Reasoning with Topological Relations in the Situation Calculus
- 2006
-
Ingår i: Proceedings of the Nineteenth International Florida Artificial Intelligence Research Society Conference, Melbourne Beach, Florida, USA, May 11-13, 2006. - : AAAI Press. - 9781577352617 ; , s. 713-718
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Konferensbidrag (refereegranskat)abstract
- We use a qualitative theory of spatial change and illustrate some of the key representational aspects of specifying such a theory using a formalism to reason about action & change; an effort that we regard to be essential toward a general integration of qualitative spatial reasoning with reasoning about the dynamic, causal aspects of spatial change. A topological theory of space, namely the region connection calculus, is used as the spatial metaphor in this work; the reason here primarily being that topological distinctions are inherently qualitative in nature and also because a relational approach as general as the RCC is representative of a similar class of relational techniques in the QSR domain. As such, our results can be easily generalised over a wide range of calculi, encompassing other aspects of space, that are based on similar semantics. The main aim of this paper is to illustrate first ideas on how a causal perspective to qualitative spatial reasoning may be provided using the situation calculus, which is a formalism to reason about dynamically changing domains, The minimalist notions of space and/or spatial dynamics in this paper are based on the hypothesis that it is imperative to approach the problem of the said integration at a elementary level before a higher-level abstraction involving complex actions & events is developed.
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| 10. |
- Bhatt, Mehul, Professor, 1980-, et al.
(författare)
-
Situation Awareness in Synthetic Environments : Towards a Computational Model
- 2005
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Ingår i: Proceedings of the 2nd Indian International Conference on Artificial Intelligence, Pune, India, December 20-22, 2005. - : IICAI. - 0972741216 - 9780972741217 ; , s. 3556-3575
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Konferensbidrag (refereegranskat)abstract
- The simulation of the behaviour of autonomous entities in space is an interesting research method to advance our understanding of the interaction of human beings with the environment. Although rather complex cognitive models of human-level Situation Awareness (SA) in dynamic environments exist, computational approaches to represent the same remain at best ad-hoc - cognitively inadequate or bearing little or no resemblance to the qualitative manner in which humans seemingly represent & reason about knowledge. The aim of our research is to investigate the computational aspects of situation awareness of autonomous entities in large-scale simulated spaces, called Synthetic Environments (SE). This is done within the scope of an understanding of situation awareness that encompasses common-sense conceptual reasoning and integrated qualitative reasoning about space, time & causality As a product of our research, we envisage to develop a logic based computational framework based on a unified representational semantics for space, time & causality - the essence of which is a process model involving abstract ontological commitments involving spatial, temporal and action event oriented concepts, alongwith a capability to handle concurrent and continuous phenomena. The framework, which is representative of our model of situation awareness, will be most beneficial for systems involving the representation of physical and/or intelligent autonomous processes. However, as an exemplar of our approach, we are interested in applying the framework for the representation of autonomous behaviour in defence Modelling & Simulation (M&S) applications.
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