The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Mounia Lalmas - One of the best experts on this subject based on the ideXlab platform.
-
SIGIR - Theoretical benchmarks of XML retrieval
Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval - SIGIR '06, 2006Co-Authors: Tobias Blanke, Mounia LalmasAbstract:This poster investigates the use of theoretical benchmarks to describe the matching functions of XML retrieval systems and the properties of specificity and exhaustivity in XML retrieval. Theoretical benchmarks concern the formal representation of qualitative properties of IR models. To this end, Situation Theory framework for the meta-evaluation of XML retrieval is presented.
-
Information retrieval and Situation Theory
ACM SIGIR Forum, 1996Co-Authors: Theo W.c. Huibers, Mounia Lalmas, C. J. Van RijsbergenAbstract:In 1986, Van Rijsbergen suggested a model of an information retrieval system based on logic. We have advocated in earlier work that a logical approach should be based on a Theory of information, Situation Theory, which provides a powerful range of concepts, and is useful for modelling documents and queries for the purpose of information retrieval. We also showed that Situation Theory provides a framework to represent different types of information retrieval models, thus allowing speculation on their properties and their characterization language. This paper is an essay to convince the reader that Situation Theory presents many characteristics that are both adequate and appropriate for the modelling and the study of information retrieval.
-
theories of information and uncertainty for the modelling of information retrieval an application of Situation Theory and dempster shafer s Theory of evidence
1996Co-Authors: Mounia LalmasAbstract:Current information retrieval models only offer simplistic and specific representations of information. Therefore, there is a need for the development of a new formalism able to model information retrieval systems in a more generic manner. In 1986, Van Rijsbergen suggested that such formalisms can be both appropriately and powerfully defined within a logic. The resulting formalism should capture information as it appears in an information retrieval system, and also in any of its inherent forms. The aim of this thesis is to understand the nature of information in information retrieval, and to propose a logic-based model of an information retrieval system that reflects this nature. The first objective of this thesis is to identify essential features of information in an information retrieval system. These are: 0 flow, 0 intensionality, 0 partiality, 0 structure, 0 significance, and o uncertainty. It is shown that the first four features are qualitative, whereas the last two are quantitative, and that their modelling requires different frameworks: a Theory of information, and a Theory of uncertainty, respectively. The second objective of this thesis is to determine the appropriate framework for each type of feature, and to develop a method to combine them in a consistent fashion. The combination is based on the Transformation Principle. Many specific attempts have been made to derive an adequate definition of information. The one adopted in this thesis is based on that of Dretske, Barwise, and Devlin who claimed that there is a primitive notion of information in terms of which a logic can be defined, and subsequently developed a Theory of information, namely Situation Theory. Their approach was in accordance with Van Rijsbergen' s suggestion of a logic-based formalism for modelling an information retrieval system. This thesis shows that Situation Theory is best at representing all the qualitative features. Regarding the modelling of the quantitative features of information, this thesis shows that the framework that models them best is the Dempster-Shafer Theory of Evidence, together with the notion of refinement, later introduced by Shafer. The third objective of this thesis is to develop a model of an information retrieval system based on Situation Theory and the Dempster-Shafer Theory of Evidence. This is done in two steps. First, the unstructured model is defined in which the structure and the significance of information are not accounted for. Second, the unstructured model is extended into the structured model, which incorporates the structure and the significance of information. This strategy is adopted because it enables the careful representation of the flow of information to be performed first. The final objective of the thesis is to implement the model and to perform empirical evaluation to assess its validity. The unstructured and the structured models are implemented based on an existing on-line thesaurus, known as WordNet. The experiments performed to evaluate the two models use the National Physical Laboratory standard test collection. The experimental performance obtained was poor, because it was difficult to extract the flow of information from the document set. This was mainly due to the data used in the experimentation which was inappropriate for the test collection. However, this thesis shows that if more appropriate data, for example, indexing tools and thesauri, were available, better performances would be obtained. The conclusion of this work was that Situation Theory, combined with the Dempster-Shafer Theory of Evidence, allows the appropriate and powerful representation of several essential features of information in an information retrieval system. Although its implementation presents some difficulties, the model is the first of its kind to capture, in a general manner, these features within a uniform framework. As a result, it can be easily generalized to many types of information retrieval systems (e.g., interactive, multimedia systems), or many aspects of the retrieval process (e.g., user modelling).
-
SOFTEKS Workshop on Incompleteness and Uncertainty in Information Systems - Situation Theory and Dempster-Shafer's Theory of Evidence for Information Retrieval
Workshops in Computing, 1994Co-Authors: Mounia Lalmas, C. J. Van RijsbergenAbstract:We propose a model of information retrieval systems that is based on a Theory of Information and a Theory of Uncertainty, respectively Situation Theory and Dempster-Shafer’s Theory of Evidence. These were selected because they allow us to tackle two of the main problems that confront any attempt to model an information retrieval system: the representation of information and its flow; and the uncertainty engendered by the complexity and ambiguity arising when dealing with information.
-
A Logical Model of Information Retrieval Based on Situation Theory
14th Information Retrieval Colloquium, 1993Co-Authors: Mounia Lalmas, Keith Van RijsbergenAbstract:We use Logics to model relevance in Information Retrieval: a document is relevant to a query if a formula q representing the query can be inferred from a formula d representing the document. Thus to infer is to retrieve, but because of the nature of aboutness often the inference is uncenain. Using a framework based on Situation Theory, the representation of documents and queries, inference, semantic and pragmatic aspects of information can be modelled formally.
Roussanka Loukanova - One of the best experts on this subject based on the ideXlab platform.
-
representing parametric concepts with Situation Theory
Federated Conference on Computer Science and Information Systems, 2015Co-Authors: Roussanka LoukanovaAbstract:We use higher-order, type-theoretic Situation Theory to model semantic concepts as Situation-theoretic objects consisting of parametric information. Situation Theory contributes by representing concepts as classes of parametric objects, in a computational way. We use concepts that are often expressed by human language in taxonomy classifications, as a demonstration of the Situation theoretic-approach to model parametric information in abstract concepts.
-
FedCSIS - Representing parametric concepts with Situation Theory
Proceedings of the 2015 Federated Conference on Computer Science and Information Systems, 2015Co-Authors: Roussanka LoukanovaAbstract:We use higher-order, type-theoretic Situation Theory to model semantic concepts as Situation-theoretic objects consisting of parametric information. Situation Theory contributes by representing concepts as classes of parametric objects, in a computational way. We use concepts that are often expressed by human language in taxonomy classifications, as a demonstration of the Situation theoretic-approach to model parametric information in abstract concepts.
-
underspecified relations with a formal language of Situation Theory
International Conference on Agents and Artificial Intelligence, 2015Co-Authors: Roussanka LoukanovaAbstract:The paper is an introduction to a formal language of Situation Theory. The language provides algorithmic processing of situated information. We introduce specialized, restricted variables that are recursively constrained to satisfy type-theoretic conditions by restrictions and algorithmic assignments. The restricted variables designate recursively connected networks of memory locations for âsavingâ parametric information that depends on Situations and restrictions over objects. The formal definitions introduce richly informative typed language for classification and representation of underspecified, parametric, and partial information that is dependent on Situations.
-
ICAART (1) - Underspecified Relations with a Formal Language of Situation Theory
Proceedings of the International Conference on Agents and Artificial Intelligence, 2015Co-Authors: Roussanka LoukanovaAbstract:The paper is an introduction to a formal language of Situation Theory. The language provides algorithmic processing of situated information. We introduce specialized, restricted variables that are recursively constrained to satisfy type-theoretic conditions by restrictions and algorithmic assignments. The restricted variables designate recursively connected networks of memory locations for âsavingâ parametric information that depends on Situations and restrictions over objects. The formal definitions introduce richly informative typed language for classification and representation of underspecified, parametric, and partial information that is dependent on Situations.
-
Situation Theory situated information and situated agents
Trans. Computational Collective Intelligence, 2014Co-Authors: Roussanka LoukanovaAbstract:Situation Theory is mathematical modelling of concepts such as information, information units, Situations, states, events, context, agents, and agent perspectives. We introduce major type-theoretical objects of Situation Theory, which model situated, partial, and parametric information. The system of situated objects is defined by mutual recursion. The main contribution to Situation Theory in this article is the distinction between situated propositions, as contents of statements and intentions, and situated factuality of the verified propositions. We use this distinction to define complex, propositional types. Another contribution is that we define complex, restricted parameters by using propositional types. The article demonstrates potential applications of the introduced complex, Situation-theoretical objects. Among the many applications of Situation Theory are developments of intelligent language processing and user-computer interfaces, by integrations of human and computer languages. We focus on modelling major objects that have potentials in such applications, e.g., contexts, situated agents, and usage of names to designate objects depending on agents and information available to agents.
Varol Akman - One of the best experts on this subject based on the ideXlab platform.
-
Situated nonmonotonic temporal reasoning with BABYdSIT
Ai Communications, 1997Co-Authors: Erkan Tin, Varol AkmanAbstract:After a review of Situation Theory and previous attempts at ‘computational’ Situation Theory, we present a new programming environment, BABYdSIT, which is based on Situation Theory. We then demonstrate how problems requiring formal temporal reasoning can be solved in this framework. Specifically, the Yale Shooting Problem, which is commonly regarded as a canonical problem for nonmonotonic temporal reasoning, is implemented in BABYdSIT using Yoav Shoham’s causal theories.
-
The Use of Situation Theory in Context Modeling
Computational Intelligence, 1997Co-Authors: Varol Akman, Mehmet SuravAbstract:At the heart of natural language processing is the understanding of context dependent meanings. This paper presents a preliminary model of formal contexts based on Situation Theory. It also gives a worked-out example to show the use of contexts in lifting, i.e., how propositions holding in a particular context transform when they are moved to another context. This is useful in NLP applications where preserving meaning is a desideratum.
-
Information-oriented computation with baby-sit
1996Co-Authors: Erkan Tin, Varol AkmanAbstract:While Situation Theory and Situation semantics provide an appropriate framework for a realistic model-theoretic treatment of natural language, serious thinking on their `computational' aspects has only recently started. Existing proposals mainly offer a Prolog- or Lisp-like programming environment with varying degrees of divergence from the ontology of Situation Theory. In this paper, we introduce a computational medium (called BABY-SIT) based on Situations. The primary motivation underlying BABY-SIT is to facilitate the development and testing of programs in domains ranging from linguistics to artificial intelligence in a unified framework built upon Situation-theoretic constructs.
-
Towards Situation-oriented programming languages
ACM SIGPLAN Notices, 1995Co-Authors: Erkan Tin, Varol Akman, Murat ErsanAbstract:Recently, there have been some attempts towards developing programming languages based on Situation Theory. These languages employ Situation-theoretic constructs with varying degrees of divergence from the ontology of the Theory. In this paper, we review three of these programming languages.
-
Modeling Context with Situations
1995Co-Authors: Mehmet Surav, Varol AkmanAbstract:The issue of context arises in assorted areas of Artificial Intelligence. Although its importance is realized by various researchers, there is not much work towards a useful formalization. In this paper, we will present a preliminary model (based on Situation Theory) and give examples to show the use of context in various fields, and the advantages gained by the acceptance of our proposal.
V Sridhar - One of the best experts on this subject based on the ideXlab platform.
-
hybrid context model based on multilevel Situation Theory and ontology for contact centers
IEEE International Conference on Pervasive Computing and Communications, 2005Co-Authors: A Kalyan, S Gopalan, V SridharAbstract:Context awareness and context modeling have raised their call for attention and importance quite recently in the world of contact centers for better customer services and relations. To address the issues of contextual reuse and contextual inconsistencies, there is a need for context models that foster context reuse and support ease of retrieving right kind of information by providing appropriate abstractions of contextual information. In this paper, we propose a hybrid context model based on multilevel Situation Theory and ontology. Multilevel Situation Theory is based on an intermediate level micro Situation that is used to create entity specific Situations. Such micro Situations are used to enhance a Situation so as to enable consistent contextual reasoning. The context model is hybrid in the sense that the proposed multilevel Situation Theory is defined based on the entities, entity attributes, and entity relationships as described in the contact center ontology. We also present an architectural overview of context aware processing system to build a rapid prototype that demonstrates the hybrid context model.
-
PerCom Workshops - Hybrid context model based on multilevel Situation Theory and ontology for contact centers
Third IEEE International Conference on Pervasive Computing and Communications Workshops, 1Co-Authors: A Kalyan, S Gopalan, V SridharAbstract:Context awareness and context modeling have raised their call for attention and importance quite recently in the world of contact centers for better customer services and relations. To address the issues of contextual reuse and contextual inconsistencies, there is a need for context models that foster context reuse and support ease of retrieving right kind of information by providing appropriate abstractions of contextual information. In this paper, we propose a hybrid context model based on multilevel Situation Theory and ontology. Multilevel Situation Theory is based on an intermediate level micro Situation that is used to create entity specific Situations. Such micro Situations are used to enhance a Situation so as to enable consistent contextual reasoning. The context model is hybrid in the sense that the proposed multilevel Situation Theory is defined based on the entities, entity attributes, and entity relationships as described in the contact center ontology. We also present an architectural overview of context aware processing system to build a rapid prototype that demonstrates the hybrid context model.
David E Levy - One of the best experts on this subject based on the ideXlab platform.
-
ASWEC (2) - Modelling Business Services with Situation Theory
Proceedings of the ASWEC 2015 24th Australasian Software Engineering Conference, 2015Co-Authors: Eugene Doma, David E LevyAbstract:In the business domain requirements are typically expressed in natural language. Any formal specifications based on high level abstractions are generally imprecise, incomplete and inconsistent. As a result the implementation of business systems often fails to deliver solutions as expected as consequence of the discontinuity between models at different levels of abstraction. Situation Theory combines linguistics and logic to form a framework for capturing and manipulating information. In this work we apply Situation Theory to process specifications defined using natural language and create formal specification artefacts which are amenable to processing using model based software engineering methods.
-
modelling business services with Situation Theory
Proceedings of the ASWEC 2015 24th Australasian Software Engineering Conference on, 2015Co-Authors: Eugene Doma, David E LevyAbstract:In the business domain requirements are typically expressed in natural language. Any formal specifications based on high level abstractions are generally imprecise, incomplete and inconsistent. As a result the implementation of business systems often fails to deliver solutions as expected as consequence of the discontinuity between models at different levels of abstraction. Situation Theory combines linguistics and logic to form a framework for capturing and manipulating information. In this work we apply Situation Theory to process specifications defined using natural language and create formal specification artefacts which are amenable to processing using model based software engineering methods.
-
exploring Situation Theory using infonlab
International Symposium on Object Component Service-Oriented Real-Time Distributed Computing, 2015Co-Authors: Eugene Doma, Bran Selic, David E LevyAbstract:Complex software systems often suffer from flaws arising either during the design or the development stages. In many cases due to the lack of formal underpinning it is difficult to assuredly define the model from which the system is generated. In our work, we investigated the suitability of mathematical Situation Theory as a formal foundation for a computer modelling language. This paper describes our empirical evaluation of this thesis in the real-time domain using Infon Lab, a tool based upon Situation Theory.
