Ilias Petrounias - Academia.edu (original) (raw)

Papers by Ilias Petrounias

2004 2nd International IEEE Conference on 'Intelligent Systems'. Proceedings (IEEE Cat. No.04EX791), 2004

... Anthony Shannon', Etienne Kerre&... more ... Anthony Shannon', Etienne Kerre', Enlalia Szmidt', Evdokia Sotirova4, Ilias Petrounias5, Janusz Kacptzyk3, Krassimir Atanassov6, Maciej Krawczak', Pedro Melo-Pinto', Peter Georgiev6, Said M elliad , Taekyun Kim9 ... Nadh Sydney, 2060, University of Technology. ...

Intelligent Decision Technologies, 2009

Intelligent Decision Technologies, 2009

ABSTRACT Female breast cancer is the major cause of cancer-related deaths in western countries. E... more ABSTRACT Female breast cancer is the major cause of cancer-related deaths in western countries. Efforts in computer vision have been made in order to help improving the diagnostic accuracy by radiologists. In this paper, we present a methodology that intends ...

International Journal of Fuzzy Logic and Intelligent Systems, 2005

ABSTRACT Using the apparatus of the generalized nets, a model for the informational exchange (ele... more ABSTRACT Using the apparatus of the generalized nets, a model for the informational exchange (electronic messages, WWW and requests to the local administrative informational system) has been developed, in the context of an abstract university Intranet.

Baltic Computer Science, 2002

Journal of Computational Methods in Sciences and Engineering, 2005

ABSTRACT In this paper we are concerned with the problem of designing of a conceptual framework f... more ABSTRACT In this paper we are concerned with the problem of designing of a conceptual framework for the construction of a flexible data warehouse that is adequate for accommodating multi-source data and selecting useful answers to queries, posted to a conflicting community of Patient-Record sources. We put forward a proposal to provide representations with that kind of functionality through flexible reasoning mechanisms for handling perception based descriptions and retrieving intentional answers. We start by positioning conceptual schema, data-warehouses with regard to this problem.

... Maria Virvou and Lakhmi C. Jain (Eds.) Intelligent Interactive Systems in Knowledge-Based Env... more ... Maria Virvou and Lakhmi C. Jain (Eds.) Intelligent Interactive Systems in Knowledge-Based Environment, 2008 ISBN 978-3-540-77470-9 Vol. ... of Value Imperfection with the Aid of Background Knowledge: H-IFS Boyan Kolev, Panagiotis Chountas, Ermir Rogova, and Krassimir ...

Proceedings of the International Conference on Computational Methods in Sciences and Engineering, Sep 12, 2003

This paper presents an intuitionistic fuzzy generalized net model of a transaction database syste... more This paper presents an intuitionistic fuzzy generalized net model of a transaction database system with continuous deadlock detection, which uses the 2PL protocol. We define probabilities for a transaction to be granted a requested lock, held back by another transaction or deadlocked, which are integrated with the intuitionistic fuzzy predicates. We can use this model to simulate transaction processing and to analyze the efficient time for useful work and the time wasted in holding back transactions.

2008 4th International Ieee Conference Intelligent Systems, Sep 1, 2008

Databases and Information Systems, 2001

ABSTRACT An abstract is not available.

Workflows are activities involving the co-ordinated execution of multiple tasks performed by enti... more Workflows are activities involving the co-ordinated execution of multiple tasks performed by entities, in the enterprise environment. Workflow systems support the encoding and execution of workflows. A workflow management system is proposed, in which a considerable attention is paid on the utilisation of the services provided by the underlying flexible database formalism. Flexible database formalisms must permit the modelling of trends, seasonality (periodicity), cyclic variations of trends and irregular activities (no predictable patterns) in the enterprise environment This paper will be restricted in workflow management system design, and activity scheduling, in a post relational environment whereas relational operators, utilise paths (links between domains), in order to express interdependencies between activities.

Chountas, Panagiotis and Kodogiannis, Vassilis and Petrounias, Ilias and Kolev, Boyan and Atanass... more Chountas, Panagiotis and Kodogiannis, Vassilis and Petrounias, Ilias and Kolev, Boyan and Atanassov, Krassimir T.(2005) On probability, null values, intuitionistic fuzzy, and value imperfection. In: Simos, Theodore E. and Maroulis, George,(eds.) International ...

International Journal of Neural Systems 2013 Vol 23, Aug 7, 2013

Load forecasting is a critical element of power system operation, involving prediction of the fut... more Load forecasting is a critical element of power system operation, involving prediction of the future level of demand to serve as the basis for supply and demand planning. This paper presents the development of a novel clustering-based fuzzy wavelet neural network (CB-FWNN) model and validates its prediction on the short-term electric load forecasting of the Power System of the Greek Island of Crete. The proposed model is obtained from the traditional Takagi-Sugeno-Kang fuzzy system by replacing the THEN part of fuzzy rules with a "multiplication" wavelet neural network (MWNN). Multidimensional Gaussian type of activation functions have been used in the IF part of the fuzzyrules. A Fuzzy Subtractive Clustering scheme is employed as a pre-processing technique to find out the initial set and adequate number of clusters and ultimately the number of multiplication nodes in MWNN, while Gaussian Mixture Models with the Expectation Maximization algorithm are utilized for the definition of the multidimensional Gaussians. The results corresponding to the minimum and maximum power load indicate that the proposed load forecasting model provides significantly accurate forecasts, compared to conventional neural networks models.

... relational data model. Kolev, Boyan and Chountas, Panagiotis and Atanassov, Krassimir T. and ... more ... relational data model. Kolev, Boyan and Chountas, Panagiotis and Atanassov, Krassimir T. and Petrounias, Ilias (2005) Representing uncertainty and ignorance in probabilistic data using the intuitionistic fuzzy relational data model. ...

Journal of Computational Methods in Sciences and Engineering 2011 11 209 225, 2011

ABSTRACT The electroencephalograph (EEG) signal is one of the most widely used signals in the bio... more ABSTRACT The electroencephalograph (EEG) signal is one of the most widely used signals in the biomedicine field due to its rich information about human tasks. This research study describes a new approach based on a fuzzy logic system implemented in the framework of a neural network for classification of EEG signals. In practical applications of pattern recognition, there are often diverse features extracted from raw data, which need recognising. Because of the importance of making the right decision, the present work is carried out for searching better classification procedures for the EEG signals. Decision making was performed in two stages: feature extraction using the wavelet transform and classification using the classifier trained on the extracted features. The proposed network constructs its initial rules by clustering, while the final fuzzy rule base is determined by competitive learning. Both error backpropagation and recursive least squares estimation, are applied to the learning scheme. The performance of the model was evaluated in terms of training performance and high classification accuracies and the results confirmed that the proposed scheme has potential in classifying the EEG signals.

2004 2nd International IEEE Conference on 'Intelligent Systems'. Proceedings (IEEE Cat. No.04EX791), 2004

... Anthony Shannon', Etienne Kerre&... more ... Anthony Shannon', Etienne Kerre', Enlalia Szmidt', Evdokia Sotirova4, Ilias Petrounias5, Janusz Kacptzyk3, Krassimir Atanassov6, Maciej Krawczak', Pedro Melo-Pinto', Peter Georgiev6, Said M elliad , Taekyun Kim9 ... Nadh Sydney, 2060, University of Technology. ...

Intelligent Decision Technologies, 2009

Intelligent Decision Technologies, 2009

ABSTRACT Female breast cancer is the major cause of cancer-related deaths in western countries. E... more ABSTRACT Female breast cancer is the major cause of cancer-related deaths in western countries. Efforts in computer vision have been made in order to help improving the diagnostic accuracy by radiologists. In this paper, we present a methodology that intends ...

International Journal of Fuzzy Logic and Intelligent Systems, 2005

ABSTRACT Using the apparatus of the generalized nets, a model for the informational exchange (ele... more ABSTRACT Using the apparatus of the generalized nets, a model for the informational exchange (electronic messages, WWW and requests to the local administrative informational system) has been developed, in the context of an abstract university Intranet.

Baltic Computer Science, 2002

Journal of Computational Methods in Sciences and Engineering, 2005

ABSTRACT In this paper we are concerned with the problem of designing of a conceptual framework f... more ABSTRACT In this paper we are concerned with the problem of designing of a conceptual framework for the construction of a flexible data warehouse that is adequate for accommodating multi-source data and selecting useful answers to queries, posted to a conflicting community of Patient-Record sources. We put forward a proposal to provide representations with that kind of functionality through flexible reasoning mechanisms for handling perception based descriptions and retrieving intentional answers. We start by positioning conceptual schema, data-warehouses with regard to this problem.

... Maria Virvou and Lakhmi C. Jain (Eds.) Intelligent Interactive Systems in Knowledge-Based Env... more ... Maria Virvou and Lakhmi C. Jain (Eds.) Intelligent Interactive Systems in Knowledge-Based Environment, 2008 ISBN 978-3-540-77470-9 Vol. ... of Value Imperfection with the Aid of Background Knowledge: H-IFS Boyan Kolev, Panagiotis Chountas, Ermir Rogova, and Krassimir ...

Proceedings of the International Conference on Computational Methods in Sciences and Engineering, Sep 12, 2003

This paper presents an intuitionistic fuzzy generalized net model of a transaction database syste... more This paper presents an intuitionistic fuzzy generalized net model of a transaction database system with continuous deadlock detection, which uses the 2PL protocol. We define probabilities for a transaction to be granted a requested lock, held back by another transaction or deadlocked, which are integrated with the intuitionistic fuzzy predicates. We can use this model to simulate transaction processing and to analyze the efficient time for useful work and the time wasted in holding back transactions.

2008 4th International Ieee Conference Intelligent Systems, Sep 1, 2008

Databases and Information Systems, 2001

ABSTRACT An abstract is not available.

Workflows are activities involving the co-ordinated execution of multiple tasks performed by enti... more Workflows are activities involving the co-ordinated execution of multiple tasks performed by entities, in the enterprise environment. Workflow systems support the encoding and execution of workflows. A workflow management system is proposed, in which a considerable attention is paid on the utilisation of the services provided by the underlying flexible database formalism. Flexible database formalisms must permit the modelling of trends, seasonality (periodicity), cyclic variations of trends and irregular activities (no predictable patterns) in the enterprise environment This paper will be restricted in workflow management system design, and activity scheduling, in a post relational environment whereas relational operators, utilise paths (links between domains), in order to express interdependencies between activities.

Chountas, Panagiotis and Kodogiannis, Vassilis and Petrounias, Ilias and Kolev, Boyan and Atanass... more Chountas, Panagiotis and Kodogiannis, Vassilis and Petrounias, Ilias and Kolev, Boyan and Atanassov, Krassimir T.(2005) On probability, null values, intuitionistic fuzzy, and value imperfection. In: Simos, Theodore E. and Maroulis, George,(eds.) International ...

International Journal of Neural Systems 2013 Vol 23, Aug 7, 2013

Load forecasting is a critical element of power system operation, involving prediction of the fut... more Load forecasting is a critical element of power system operation, involving prediction of the future level of demand to serve as the basis for supply and demand planning. This paper presents the development of a novel clustering-based fuzzy wavelet neural network (CB-FWNN) model and validates its prediction on the short-term electric load forecasting of the Power System of the Greek Island of Crete. The proposed model is obtained from the traditional Takagi-Sugeno-Kang fuzzy system by replacing the THEN part of fuzzy rules with a "multiplication" wavelet neural network (MWNN). Multidimensional Gaussian type of activation functions have been used in the IF part of the fuzzyrules. A Fuzzy Subtractive Clustering scheme is employed as a pre-processing technique to find out the initial set and adequate number of clusters and ultimately the number of multiplication nodes in MWNN, while Gaussian Mixture Models with the Expectation Maximization algorithm are utilized for the definition of the multidimensional Gaussians. The results corresponding to the minimum and maximum power load indicate that the proposed load forecasting model provides significantly accurate forecasts, compared to conventional neural networks models.

... relational data model. Kolev, Boyan and Chountas, Panagiotis and Atanassov, Krassimir T. and ... more ... relational data model. Kolev, Boyan and Chountas, Panagiotis and Atanassov, Krassimir T. and Petrounias, Ilias (2005) Representing uncertainty and ignorance in probabilistic data using the intuitionistic fuzzy relational data model. ...

Journal of Computational Methods in Sciences and Engineering 2011 11 209 225, 2011

ABSTRACT The electroencephalograph (EEG) signal is one of the most widely used signals in the bio... more ABSTRACT The electroencephalograph (EEG) signal is one of the most widely used signals in the biomedicine field due to its rich information about human tasks. This research study describes a new approach based on a fuzzy logic system implemented in the framework of a neural network for classification of EEG signals. In practical applications of pattern recognition, there are often diverse features extracted from raw data, which need recognising. Because of the importance of making the right decision, the present work is carried out for searching better classification procedures for the EEG signals. Decision making was performed in two stages: feature extraction using the wavelet transform and classification using the classifier trained on the extracted features. The proposed network constructs its initial rules by clustering, while the final fuzzy rule base is determined by competitive learning. Both error backpropagation and recursive least squares estimation, are applied to the learning scheme. The performance of the model was evaluated in terms of training performance and high classification accuracies and the results confirmed that the proposed scheme has potential in classifying the EEG signals.