Panos Alexopoulos | National Technical University of Athens (original) (raw)

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Papers by Panos Alexopoulos

Fraud detection and prevention systems are based on various technological paradigms but the most ... more Fraud detection and prevention systems are based on various technological paradigms but the most prevailing one is rule-based reasoning. However, most of the existing rule-based fraud detection systems consist of fixed and inflexible decision-making rules which limit significantly the effectiveness of such systems. In this paper we present a fraud detection approach which combines the technologies of knowledge-based systems and adaptive systems in order to overcome the limitations of traditional rule-based reasoning.

In this paper we try to solve the Temporal Resource Real-location Problem (TRR-P) in multi-agent ... more In this paper we try to solve the Temporal Resource Real-location Problem (TRR-P) in multi-agent systems by having the agents negotiate periods of time during which they can have use of resources. Our work is based on and extends a previous work in which a multistage negotiation framework that defines the way agents negotiate over resources and time is defined.

In the modern business environment, the capability of an enterprise to generate value from its bu... more In the modern business environment, the capability of an enterprise to generate value from its business knowledge influences in an increasingly important way its competitiveness. Towards this direction, knowledge-based systems can be a very effective tool for enhancing the productivity of knowledge workers by providing them with advanced knowledge processing capabilities.

Abstract Uncertainty and imprecision are inherent characteristics of human knowledge and their ro... more Abstract Uncertainty and imprecision are inherent characteristics of human knowledge and their role in knowledge engineering and knowledge-based systems development has been extensively examined in the literature. However, when it comes to enterprise knowledge management, existence of corresponding frameworks that are able to address the issue of knowledge imprecision in a formal and comprehensive way is limited.

Abstract. Knowledge deriving from owned information and experience is an asset that has begun to ... more Abstract. Knowledge deriving from owned information and experience is an asset that has begun to be recognised by organizations of various scales as a marketable product. In previous work we have developed a system that facilitated the formal description of knowledge possessed by an organization, so that external entities could search in it and request it.

Abstract Semantic tagging of a textual document involves identifying and assigning to it appropri... more Abstract Semantic tagging of a textual document involves identifying and assigning to it appropriate entities that best summarize its content, ie entities that constitute a representative description of what the document is specifically about. The effective automation of this process requires from the system to be able to distinguish between the entities that play a central role to the documents's meaning and those that are just complementary to it.

In this chapter we combine theory from ontologies, case base reasoning and fuzzy algebra to const... more In this chapter we combine theory from ontologies, case base reasoning and fuzzy algebra to construct a novel framework for semantic-enabled information access. This framework is able to provide a comprehensive and effective way for the development of semantic information retrieval systems aimed to serve specific domains and operate in under specific contexts.

The advent and wide proliferation of Social Web in the recent years has promoted the concept of s... more The advent and wide proliferation of Social Web in the recent years has promoted the concept of social interaction as an important influencing factor of the way enterprises and organizations conduct business. Among the fields influenced is that of Enterprise Knowledge Management, where adoption of social computing approaches aims at increasing and maintaining at high levels the active participation of users in the organization's knowledge management activities.

Abstract Fuzzy Ontologies comprise a relatively new knowledge representation paradigm that is bei... more Abstract Fuzzy Ontologies comprise a relatively new knowledge representation paradigm that is being increasingly applied in application scenarios in which the treatment and utilization of vague or imprecise knowledge are important.

In this position paper, we illustrate how Linked Data can be effectively used in a Technology-enh... more In this position paper, we illustrate how Linked Data can be effectively used in a Technology-enhanced Learning scenario. Specifically, we aim at using structured data to semi-automatically generate artifacts to support learning delivery and assessment: natural language facts, Q&A systems and quizzes, also used with a gaming favour, can be creatively generated to help teachers and learners to support and improve the learning path.

Abstract Manual ontology development is clearly a strenuous task. Whilst a variety of ontological... more Abstract Manual ontology development is clearly a strenuous task. Whilst a variety of ontological engineering methodologies exist, their actual application is far from trivial, mainly due to the widely diverse nature of the tasks involved. In this work we study these tasks and identify the different types of human experts that are best suited to perform each one. As a result, we present a cooperative version of an special purpose ontological engineering methodology, together with a graphical tool that supports it.

Abstract The ability to estimate semantic similarity between entities in a meaningful way suiting... more Abstract The ability to estimate semantic similarity between entities in a meaningful way suiting the needs of a specific application is crucial for the success of any information system build using ontologies. As a result, ontology reutilization to this day has been limited, with most systems being accompanied by ontologies perfectly customized for the system's needs.

Abstract: Assigning geographical meta-information to textual pieces of information in an automati... more Abstract: Assigning geographical meta-information to textual pieces of information in an automatic way is a challenging semantic processing task that has been getting increasing attention from application and research areas that need to exploit this kind of information.

Abstract: The European iWebCare project (FP6-2004-IST-4-028055) aims at designing and developing ... more Abstract: The European iWebCare project (FP6-2004-IST-4-028055) aims at designing and developing a flexible fraud detection web services platform, which will be able to serve e-government processes of fraud detection and prevention, in order to ensure quality and accuracy and minimize loss of health care funds.

Abstract. One of the primary focuses of Semantic Business Process Management is the application o... more Abstract. One of the primary focuses of Semantic Business Process Management is the application of ontology-based semantics for the machine processable representation of business processes and the automation of their management lifecycle. Towards that direction, various ontologies have been proposed, each covering one or more aspects of the knowledge required to describe a business process.

Whilst a variety of ontological engineering methodologies exist, their actual application is far ... more Whilst a variety of ontological engineering methodologies exist, their actual application is far from trivial, mainly due to the widely diverse nature of the steps involved, that require different forms of expertise, typically possessed by different individuals. In order to address this, in this work we propose the separation between the conceptualization and formalization parts of the process.

Automatically learned social ontologies are products of social fermentation between users that be... more Automatically learned social ontologies are products of social fermentation between users that belong in communities of common interests (CoI), in open, collaborative and communicative environments. In such a setting, social fermentation ensures automatic encapsulation of agreement and trust of the shared knowledge of participating stakeholders during an ontology learning process.

Abstract In this paper we propose a novel method for automatically generating and recommending se... more Abstract In this paper we propose a novel method for automatically generating and recommending semantic tags for text documents, namely terms that reflect the intended meaning of the document in an accurate and complete way. Our approach is based on the utilization of existing domain knowledge, in the form of ontologies, and particularly in the selection and exploitation of those ontological relations that are most appropriate for the given tagging scenario and domain.

Abstract. The rapidly increasing use of large-scale data on the Web has made named entity disambi... more Abstract. The rapidly increasing use of large-scale data on the Web has made named entity disambiguation a key research challenge in Information Extraction (IE) and development of the Semantic Web. In this paper we propose a novel disambiguation framework that utilizes background semantic information, typically in the form of Linked Data, to accurately determine the intended meaning of detected semantic entity references within texts.

Fraud detection and prevention systems are based on various technological paradigms but the most ... more Fraud detection and prevention systems are based on various technological paradigms but the most prevailing one is rule-based reasoning. However, most of the existing rule-based fraud detection systems consist of fixed and inflexible decision-making rules which limit significantly the effectiveness of such systems. In this paper we present a fraud detection approach which combines the technologies of knowledge-based systems and adaptive systems in order to overcome the limitations of traditional rule-based reasoning.

In this paper we try to solve the Temporal Resource Real-location Problem (TRR-P) in multi-agent ... more In this paper we try to solve the Temporal Resource Real-location Problem (TRR-P) in multi-agent systems by having the agents negotiate periods of time during which they can have use of resources. Our work is based on and extends a previous work in which a multistage negotiation framework that defines the way agents negotiate over resources and time is defined.

In the modern business environment, the capability of an enterprise to generate value from its bu... more In the modern business environment, the capability of an enterprise to generate value from its business knowledge influences in an increasingly important way its competitiveness. Towards this direction, knowledge-based systems can be a very effective tool for enhancing the productivity of knowledge workers by providing them with advanced knowledge processing capabilities.

Abstract Uncertainty and imprecision are inherent characteristics of human knowledge and their ro... more Abstract Uncertainty and imprecision are inherent characteristics of human knowledge and their role in knowledge engineering and knowledge-based systems development has been extensively examined in the literature. However, when it comes to enterprise knowledge management, existence of corresponding frameworks that are able to address the issue of knowledge imprecision in a formal and comprehensive way is limited.

Abstract. Knowledge deriving from owned information and experience is an asset that has begun to ... more Abstract. Knowledge deriving from owned information and experience is an asset that has begun to be recognised by organizations of various scales as a marketable product. In previous work we have developed a system that facilitated the formal description of knowledge possessed by an organization, so that external entities could search in it and request it.

Abstract Semantic tagging of a textual document involves identifying and assigning to it appropri... more Abstract Semantic tagging of a textual document involves identifying and assigning to it appropriate entities that best summarize its content, ie entities that constitute a representative description of what the document is specifically about. The effective automation of this process requires from the system to be able to distinguish between the entities that play a central role to the documents's meaning and those that are just complementary to it.

In this chapter we combine theory from ontologies, case base reasoning and fuzzy algebra to const... more In this chapter we combine theory from ontologies, case base reasoning and fuzzy algebra to construct a novel framework for semantic-enabled information access. This framework is able to provide a comprehensive and effective way for the development of semantic information retrieval systems aimed to serve specific domains and operate in under specific contexts.

The advent and wide proliferation of Social Web in the recent years has promoted the concept of s... more The advent and wide proliferation of Social Web in the recent years has promoted the concept of social interaction as an important influencing factor of the way enterprises and organizations conduct business. Among the fields influenced is that of Enterprise Knowledge Management, where adoption of social computing approaches aims at increasing and maintaining at high levels the active participation of users in the organization's knowledge management activities.

Abstract Fuzzy Ontologies comprise a relatively new knowledge representation paradigm that is bei... more Abstract Fuzzy Ontologies comprise a relatively new knowledge representation paradigm that is being increasingly applied in application scenarios in which the treatment and utilization of vague or imprecise knowledge are important.

In this position paper, we illustrate how Linked Data can be effectively used in a Technology-enh... more In this position paper, we illustrate how Linked Data can be effectively used in a Technology-enhanced Learning scenario. Specifically, we aim at using structured data to semi-automatically generate artifacts to support learning delivery and assessment: natural language facts, Q&A systems and quizzes, also used with a gaming favour, can be creatively generated to help teachers and learners to support and improve the learning path.

Abstract Manual ontology development is clearly a strenuous task. Whilst a variety of ontological... more Abstract Manual ontology development is clearly a strenuous task. Whilst a variety of ontological engineering methodologies exist, their actual application is far from trivial, mainly due to the widely diverse nature of the tasks involved. In this work we study these tasks and identify the different types of human experts that are best suited to perform each one. As a result, we present a cooperative version of an special purpose ontological engineering methodology, together with a graphical tool that supports it.

Abstract The ability to estimate semantic similarity between entities in a meaningful way suiting... more Abstract The ability to estimate semantic similarity between entities in a meaningful way suiting the needs of a specific application is crucial for the success of any information system build using ontologies. As a result, ontology reutilization to this day has been limited, with most systems being accompanied by ontologies perfectly customized for the system's needs.

Abstract: Assigning geographical meta-information to textual pieces of information in an automati... more Abstract: Assigning geographical meta-information to textual pieces of information in an automatic way is a challenging semantic processing task that has been getting increasing attention from application and research areas that need to exploit this kind of information.

Abstract: The European iWebCare project (FP6-2004-IST-4-028055) aims at designing and developing ... more Abstract: The European iWebCare project (FP6-2004-IST-4-028055) aims at designing and developing a flexible fraud detection web services platform, which will be able to serve e-government processes of fraud detection and prevention, in order to ensure quality and accuracy and minimize loss of health care funds.

Abstract. One of the primary focuses of Semantic Business Process Management is the application o... more Abstract. One of the primary focuses of Semantic Business Process Management is the application of ontology-based semantics for the machine processable representation of business processes and the automation of their management lifecycle. Towards that direction, various ontologies have been proposed, each covering one or more aspects of the knowledge required to describe a business process.

Whilst a variety of ontological engineering methodologies exist, their actual application is far ... more Whilst a variety of ontological engineering methodologies exist, their actual application is far from trivial, mainly due to the widely diverse nature of the steps involved, that require different forms of expertise, typically possessed by different individuals. In order to address this, in this work we propose the separation between the conceptualization and formalization parts of the process.

Automatically learned social ontologies are products of social fermentation between users that be... more Automatically learned social ontologies are products of social fermentation between users that belong in communities of common interests (CoI), in open, collaborative and communicative environments. In such a setting, social fermentation ensures automatic encapsulation of agreement and trust of the shared knowledge of participating stakeholders during an ontology learning process.

Abstract In this paper we propose a novel method for automatically generating and recommending se... more Abstract In this paper we propose a novel method for automatically generating and recommending semantic tags for text documents, namely terms that reflect the intended meaning of the document in an accurate and complete way. Our approach is based on the utilization of existing domain knowledge, in the form of ontologies, and particularly in the selection and exploitation of those ontological relations that are most appropriate for the given tagging scenario and domain.

Abstract. The rapidly increasing use of large-scale data on the Web has made named entity disambi... more Abstract. The rapidly increasing use of large-scale data on the Web has made named entity disambiguation a key research challenge in Information Extraction (IE) and development of the Semantic Web. In this paper we propose a novel disambiguation framework that utilizes background semantic information, typically in the form of Linked Data, to accurately determine the intended meaning of detected semantic entity references within texts.