Papers by Christopher Matheus
Proceedings of SPIE, Apr 12, 2004
After a number of years of intensive research on Level 1 fusion, the focus is shifting to higher ... more After a number of years of intensive research on Level 1 fusion, the focus is shifting to higher levels. Level 2 fusion differs from Level 1 fusion in its emphasis on relations among objects rather than on the characteristics (position, velocity, type) of single objects. While the number of such characteristics grows linearly with the number of objects considered by an information fusion system, this cannot be said about the number of possible relations, which can grow exponentially. To alleviate the problems of computational complexity in Level 2 processing, the authors of this paper have suggested the use of ontologies. In this paper we analyze the issue of association in Level 2 fusion. In particular, we investigate ways in which the use of ontologies and annotations of situations in terms of the ontologies can be used for deciding which of the objects, and/or relations among such, can be considered to be the same. This is analogous to data association in Level 1 fusion. First, we show the kinds of reasoning that can be carried out on the annotations in order to identify various objects and possible coreferences. Second, we analyze how uncertainty information can be incorporated into the process. The reasoning aspect depends on the features of the ontology representation language used. We focus on OWLthe web ontology language. This language comprises, among others, constructs related to expressing multiplicity constraints as well as such features like "functional property" and "inverse functional property". We will show how these features can be used in resolving the identities of objects and relations. Moreover, we will show how a consistency-checking tool (ConsVISor) developed by the authors can be used in this process.
Proceedings of SPIE, Apr 2, 2003
This paper describes a case study of relation derivation within the context of situation awarenes... more This paper describes a case study of relation derivation within the context of situation awareness. First we present a scenario in which inputs are supplied by a simulated Level 1 system. The inputs are events annotated with terms from an ontology for situation awareness. This ontology contains concepts used to represent and reason about situations. The ontology and the annotations of events are represented in DAML and Rule-ML and then systematically translated to a formal method language called MetaSlang. Having all information expressed in a formal method language allows us to use a theorem prover, SNARK, to prove that a given relationship among the Level 1 objects holds (or that it does not hold). The paper shows a proof of concept that relation derivation in situation awareness can be done within a formal framework. It also identifies bottlenecks associated with this approach, such as the issue of the large number of potential relations that may have to be considered by the theorem prover. The paper discusses ways of resolving this as well as other problems identified in this study.
Proceedings of SPIE, Mar 28, 2005
Situation awareness involves the identification and monitoring of relationships among level-one o... more Situation awareness involves the identification and monitoring of relationships among level-one objects. This problem in general is intractable (i.e., there is a potentially infinite number of relations that could be tracked) and thus requires additional constraints and guidance defined by the user if there is to be any hope of creating practical situation awareness systems. This paper describes a Situation Awareness Assistant (SAWA) that facilitates the development of user-defined domain knowledge in the form of formal ontologies and rule sets and then permits the application of the domain knowledge to the monitoring of relevant relations as they occur in evolving situations. SAWA includes tools for developing ontologies in OWL and rules in SWRL and provides runtime components for collecting event data, storing and querying the data, monitoring relevant relations and viewing the results through a graphical user interface. An application of SAWA to a scenario from the domain of supply logistics is also presented.
After a number of years of intensive research on Level 1 fusion, the focus is shifting to higher ... more After a number of years of intensive research on Level 1 fusion, the focus is shifting to higher levels. Level 2 fusion differs from Level 1 fusion in its emphasis on relations among objects rather than on the characteristics (position, velocity, type) of single objects. While the number of such characteristics grows linearly with the number of objects considered by an information fusion system, this cannot be said about the number of possible relations, which can grow exponentially. To alleviate the problems of computational complexity in Level 2 processing, the authors of this paper have suggested the use of ontologies. In this paper we analyze the issue of association in Level 2 fusion. In particular, we investigate ways in which the use of ontologies and annotations of situations in terms of the ontologies can be used for deciding which of the objects, and/or relations among such, can be considered to be the same. This is analogous to data association in Level 1 fusion. First, we show the kinds of reasoning that can be carried out on the annotations in order to identify various objects and possible coreferences. Second, we analyze how uncertainty information can be incorporated into the process. The reasoning aspect depends on the features of the ontology representation language used. We focus on OWLthe web ontology language. This language comprises, among others, constructs related to expressing multiplicity constraints as well as such features like "functional property" and "inverse functional property". We will show how these features can be used in resolving the identities of objects and relations. Moreover, we will show how a consistency-checking tool (ConsVISor) developed by the authors can be used in this process.
The International Journal of Sport and Society
The main role of this paper is description of basic ideasandcurrentresultsoftheinternational Cope... more The main role of this paper is description of basic ideasandcurrentresultsoftheinternational Copernicus research project No. 977091 GOAL-Geographic Information On-Line Analysis (GIS – Data Warehouse Integration), mainly focusing on its knowledge discovery part. Regarding the knowledge extracting phase, a KDD (Knowledge Discovery in Databases) package has been developed within this projectattheDepartmentofCyberneticsand Artificial Intelligence. 1 INTRODUCTION The integration and combination of GIS (Geographic Information System) data into and with OLAP systems poses a number of yet not satisfyingly solv ed problems in terms of getting the data into the OLAP system,representingthedataforanalysisand extractingknowledgewhileconsideringsecurity restrictions. Current approaches do not address the se special problems resulting from the targeted application arena of GIS and OLAP systems. The main objective of the GOAL project is to develop a generic framework both recognized by the research...
The Key Findings Reporter (KEFIR) is a system for discovering and explaining "key findings&q... more The Key Findings Reporter (KEFIR) is a system for discovering and explaining "key findings" in large, relational databases. This paper describes an application of KEFIR to the analysis of health-care information. The system performs an automatic analysis of data along multiple dimensions to determine the most interesting deviations of specific quantitative measures relative to norms and previous values. It explains key findings through their relationship to other findings in the data, and, where possible, generates simple recommendations for correcting detected problems. A final written report, complete with business graphics, is produced for viewing remotely over the internet with Mosaic, or for printing to hardcopy. Keywords: knowledge discovery, databases, health care 1 Introduction Knowledge discovery techniques are being used successfully today to analyze and explore large databases in numerous scientific, financial, and manufacturing domains [PiatetskyShapiro, 1993, ...
We present an iterative algorithm for nonlinear regression based on construction of sparse polyno... more We present an iterative algorithm for nonlinear regression based on construction of sparse polynomials. Polynomials are built sequentially from lower to higher order. Selection of new terms is accomplished using a novel look-ahead approach that predicts whether a variable contributes to the remaining error. The algorithm is based on the tree-growing heuristic in LMS Trees which we have extended to approximation of arbitrary polynomials of the input features. In addition, we provide a new theoretical justification for this heuristic approach. The algorithm is shown to discover a known polynomial from samples, and to make accurate estimates of pixel values in an image-processing task.
Ontologies are becoming increasingly popular due to recent e#orts to extend the capabilities of t... more Ontologies are becoming increasingly popular due to recent e#orts to extend the capabilities of the World Wide Web through the addition of formal semantics. While ontologies have traditionally been used as precise languages to facilitate e#cient exchange of information among people, the "Semantic Web" is extending this role to software agents. For this to be possible, ontologies must be formalized in languages processable by computers, such as OWL, the W3C's Web Ontology Language. The purpose of OWL ontologies is to permit software agents to understand web content and to interact intelligently with Web services (which may themselves be software agents). The use of such ontologies, however, need not be constrained to the Web. Recently, ontologies have found their way into higher-level information fusion where they are providing a means for describing and reasoning about sensor data, objects, relations and general domain theories. To the best of our knowledge, there is ...
Versatile Information Systems, Inc. (VIS) has been applying Semantic Web technologies to the prob... more Versatile Information Systems, Inc. (VIS) has been applying Semantic Web technologies to the problems of situation awareness and information fusion for more than five years. Situation awareness involves the real-time processing of event-based information coming from an evolving situation in an attempt to understand what is happening. In our view, situation awareness primarily comes down to identifying higher-order relations that come into being within a situation and that have particular relevance to the problem at hand as defined by the user’s goals or objectives,. By higher-order relations we mean relations involving multiple objects; OWL ObjectProperties represent the simplest of such relations involving two objects but situation awareness is often interested in more complex relations involving several objects. We contrast these higher-order relations with those that merely define characteristics of an individual object; DataProperties fall into this category. The analytical proc...
SAWA is a situation awareness assistant being developed by Versatile Information Systems, Inc. Du... more SAWA is a situation awareness assistant being developed by Versatile Information Systems, Inc. During the process of its development, several lessons were learned about advantages and limitations of certain approaches, techniques, and technologies as they are applied to situation awareness. This paper begins with an overview of SAWA and then focuses on some of the more significant lessons learned. These include the pros and cons of leveraging semantic Web technologies, the handling of time-varying attributes, and the processing of uncertainty.
The authors' automated framework evaluates blog posts in a social-political blogosphere and, ... more The authors' automated framework evaluates blog posts in a social-political blogosphere and, by aggregation, entire blogs according to their relevance, specificity, timeliness, and credibility. These metrics are superior to current methods in information retrieval for blogs because they better reflect the distinctive hyperlink structure of a social-political blogosphere than do other methods. The authors chose the Malaysian social-political blogosphere as a case study because of the role Malaysian bloggers played leading up to that country's 2008 general election, and afterward.
BaseVISor is a forward-chaining inference engine based on a Rete network optimized for the proces... more BaseVISor is a forward-chaining inference engine based on a Rete network optimized for the processing of RDF triples. A clause within the body and head of a rule either represents an RDF triple or invokes a procedural attachment (either built-in or user defined). This paper describes how BaseVISor has been outfitted to process RuleML and R-Entailment rules. In the case of RuleML, n-ary predicates are automatically translated into binary predicates and reified statements that encapsulate the n-ary predicates' arguments. For R-Entailment rules, the appropriate R-Entailment axioms, axiomatic triples and consistency rules are automatically imported into the engine and then used to derive all triples entailed by any set of triples asserted into the fact base. Operation of the system is illustrated using sample rule sets for both RuleML and R-Entailment and instructions are provided on how to obtain the BaseVISor beta release and process the examples
Situation awareness involves the identification of relationships among objects participating in a... more Situation awareness involves the identification of relationships among objects participating in an evolving situation. This problem in general is intractable and thus requires additional constraints and guidance defined by the user if there is to be any hope of creating practical situation awareness systems. This paper describes a Situation Awareness Assistant (SAWA) based on Semantic Web technologies that facilitates the development of user-defined domain knowledge in the form of formal ontologies and rule sets and then permits the application of the domain knowledge to the monitoring of relevant relations as they occur in a situations. SAWA includes tools for developing ontologies in OWL and rules in SWRL and provides runtime components for collecting event data, storing and querying the data, monitoring relevant relations and viewing the results through a graphical user interface. An application of SAWA to a scenario from the domain of supply logistics is presented along with a d...
: This paper describes the authors' efforts to develop a pedigree ontology for level-one sens... more : This paper describes the authors' efforts to develop a pedigree ontology for level-one sensor fusion. This work was performed in the context of naval operations but the concepts employed are applicable to any domain involving sensor fusion. The ontology that has been developed is formally represented using OWL, the Web Ontology Language used in defining ontologies for the Semantic Web. One advantage of using OWL is that it has a formal semantics and there is a growing number of formal systems for processing and reasoning about OWL-based documents. The paper will describe the pedigree ontology in detail along with the motivation for various design decisions. An example will be given of the ontology's use in conjunction with OTH-T GOLD track data; in a simulated scenario pedigree information permits the informed selection of preferred vessel tracks. The paper concludes with a discussion of open issues and future directions.
: The goal of this paper is to raise some of the fundamental questions that underpin the developm... more : The goal of this paper is to raise some of the fundamental questions that underpin the development of formal ontologies, especially the ones that are used for systems interoperability. To realize this, the three authors independently collaborated on different aspects of this paper. In this way, questions naturally arose from the review of each others work. In essence, this paper represents the genesis of the authors collaboration and constitutes for them a basis for future research.
Computational Intelligence
Ontologies are becoming increasingly popular due to recent efforts to extend the capabilities of ... more Ontologies are becoming increasingly popular due to recent efforts to extend the capabilities of the World Wide Web through the addition of formal semantics. While ontologies have traditionally been used as precise languages to facilitate efficient exchange of information among people, the "Semantic Web" is extending this role to software agents. For this to be possible, ontologies must be formalized in languages processable by computers, such as OWL, the W3C's Web Ontology Language. The purpose of OWL ontologies is to permit software agents to understand web content and to interact intelligently with Web services (which may themselves be software agents). The use of such ontologies, however, need not be constrained to the Web. Recently, ontologies have found their way into higher-level information fusion where they are providing a means for describing and reasoning about sensor data, objects, relations and general domain theories. To the best of our knowledge, there is as of yet no documented effort to capture the main uses of ontologies in information fusion. In this paper we start filling this void by presenting a number of "use cases," i.e., scenarios of the use of ontologies in the context of higher-level information fusion. In this paper we develop use cases in which ontologies are used both for the fusion process itself and for the development of fusion systems. The use cases cover scenarios in which the agent roles are played by people, software or both.
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Papers by Christopher Matheus