Tjortjis Christos Assistant Professor, School of Science and Technology

Dr. Christos Tjortjis is an assistant professor elect in Decision Support and Knowledge Discovery systems at the IHU, School of Science and Technology, and an honorary lecturer at the University of Manchester, School of Computer Science. He worked (2008-11) as adjunct assistant professor at the University of Ioannina, Dept. of Computer Science, and adjunct assistant professor at the University of Western Macedonia, Dept. Engineering Informatics and Telecommunications. He also worked (2002-08) as a tenured lecturer for the University of Manchester, Schools of Informatics and School of Computer Science as well as for UMIST, Dept. of Computation.

He received a PhD in Informatics from the University of Manchester in 2006, an MPhil in Computation from UMIST in 1999, a BSc in Law from the Demokritos University of Thrace in 1997 and a Diploma of Engineering in Computer Engineering and Informatics from the the University of Patras in 1993.

His research interests include knowledge discovery and data mining, particularly in software, medical and biological data. He published over 40 papers in int’l journals and conferences. He was on the Program Committee of more than 50 and on the Organizational Committee of 9 conferences / workshops. He has been involved in several projects concerning data and text mining, data recovery, software quality and evolution etc., leading 7 of them.

Personal webpage: http://www.cs.uoi.gr/~tjortjis/

Research Areas: Data Mining, Biological Data Mining / Bioinformatics, Software Management

Selected Publications

• Kanellopoulos Y., Antonellis P., Tjortjis C., Makris C. and Tsirakis N., "k-Attractors: A Partitional Clustering Algorithm for Numeric Data analysis", Applied Artificial Intelligence, Taylor & Francis, Vol. 25, No.2, pp. 97-115 (2011) • Journal Paper
• Kanellopoulos Y., Antonellis P., Antoniou D., Makris C., Theodoridis E., Tjortjis C. and Tsirakis N., "Code Quality Evaluation methodology using the ISO/IEC 9126 Standard", Int’l Journal of Software Engineering & Applications, AIRCC, Vol.1, No.3, pp. 17-36 (2010) • Journal Paper
• Antonellis P., Antoniou D., Kanellopoulos Y., Makris C., Theodoridis E., Tjortjis C. and Tsirakis N., "Clustering for Monitoring Software Systems Maintainability Evolution", Electronic Notes in Theoretical Computer Science, Elsevier, Vol. 233, pp. 43-57 (2009) • Journal Paper
• Antonellis P., Antoniou D., Kanellopoulos Y., Makris C., Theodoridis E., Tjortjis C. and Tsirakis N., "Code4Thought Project: Employing the ISO/IEC-9126 standard for Software Engineering - Product Quality Assessment", Proc. IEEE 13th European Conf. Software Maintenance and Reengineering (CSMR 2009), pp. 297-300 (2009) • Conference Paper
• Denaxas S. and Tjortjis C., "A GO-driven semantic similarity measure for quantifying the biological relatedness of gene products", Intelligent Decision Technologies journal, IOS Press, Vol. 3, No 4, pp. 239-248 (2009) • Journal Paper
• Kontogiannis K., Tjortjis C., and Winter A. (eds.), "Editorial for a Special Issue on the 12th Conf. on Software Maintenance and Reengineering", Journal of Software Maintenance and Evolution: Research and Practice, Wiley, Vol. 21, No. 2, pp. 79–80 (2009) • Journal Paper
• Zhang S., Tjortjis C., Zeng X., Qiao H., Buchan I. and Keane J., "Comparing Data Mining Methods with Logistic Regression in Childhood Obesity Prediction", Information Systems Frontiers Journal, Springer, Vol. 11, No. 4, pp. 449-460 (2009) • Journal Paper
• Antonellis P., Antoniou D., Kanellopoulos Y., Makris C., Theodoridis E., Tjortjis C. and Tsirakis N., "Employing Clustering for Assisting Source Code Maintainability Evaluation according to ISO/IEC-9126", Proc. Artificial Intelligence Techniques in Software Engineering Workshop (AISEW 2008) (2008) • Conference Paper
• Denaxas S. and Tjortjis C., "Scoring and summarizing gene product clusters using the Gene Ontology", Int’l Journal of Data Mining and Bioinformatics, Inderscience, Vol. 2, No. 3, pp.216- 235 (2008) • Journal Paper
• Kanellopoulos Y., Heitlager I., Tjortjis C., and Visser J., "Interpretation of Source Code Clusters in Terms of the ISO/IEC-9126 Maintainability Characteristics", Proc. 12th European Conf. Software Maintenance and Reengineering (CSMR 2008), pp. 63-72 (2008) • Conference Paper
• Kanellopoulos Y., Antonellis P., Tjortjis C. and Makris C., "k-Attractors: A Clustering Algorithm for Software Measurement Data Analysis", Proc. 19th IEEE Int’l Conf. on Tools with Artificial Intelligence (ICTAI 07), pp. 358-365 (2007) • Conference Paper
• Kanellopoulos Y., Makris C. and Tjortjis C., "An Improved Methodology on Information Distillation by Mining Program Source Code", Data & Knowledge Engineering, Elsevier, Vol. 61, No 2, pp. 359-383 (2007) • Journal Paper
• Tjortjis C. and Wang C., "HybridSet: An Effective Approach to Association Rule Mining", Proc. 2007 European Conference on Operational Research (EURO XXII) (2007) • Conference Paper
• Tjortjis C., Saraee M., Theodoulidis B. and Keane J.A., "Using T3, an Improved Decision Tree Classifier, for Mining Stroke Related Medical Data", Methods of Information in Medicine, Schattauer GmbH, Vol. 46, No. 5, pp. 523-529 (2007) • Journal Paper
• Denaxas S. and Tjortjis C., "Quantifying the Biological Similarity between Gene Products Using GO: An Application of the Vector Space Model", Proc. IEEE Information Technology in Biomedicine (ITAB 2006) (2006) • Conference Paper
• Kanellopoulos Y., Dimopoulos T., Tjortjis C. and Makris C., "Mining Source Code Elements for Comprehending Object-Oriented Systems and Evaluating Their Maintainability", SIGKDD Explorations, ACM Press, Vol. 8, No. 1, pp. 33-40 (2006) • Journal Paper
• Marchant J., Tjortjis C., and Turega M., "A Metric of Confidence in Requirements Gathered from Legacy Systems: Two Industrial Case Studies", Proc. IEEE 10th European Conf. Software Maintenance and Reengineering (CSMR 2006), pp. 353-359 (2006) • Conference Paper
• Muyeba M., Khan M., Malik, Z. and Tjortjis C., "Towards Healthy Association Rule Mining (HARM): A Fuzzy Quantitative Approach", Lecture Notes in Computer Science, Springer-Verlag, Vol. 4224, pp. 1014-1022 (2006) • Journal Paper
• Rousidis D. and Tjortjis C., "Clustering data retrieved from Java source code to support software maintenance: A case study", Proc. IEEE 9th European Conf. Software Maintenance and Reengineering (CSMR 2005), pp. 276-279 (2005) • Conference Paper
• Kanellopoulos Y. and Tjortjis C., "Data Mining Source Code to Facilitate Program Comprehension: Experiments on Clustering Data Retrieved from C++ Programs", Proc. IEEE 12th Int’l Workshop Program Comprehension (IWPC 2004), pp. 214-223 (2004) • Conference Paper
• Wang C. and Tjortjis C., "PRICES: An Efficient Algorithm for Mining Association Rules", Lecture Notes in Computer Science, Springer-Verlag, Vol. 3177, pp. 352-358 (2004) • Journal Paper
• Tjortjis C., Sinos L. and Layzell P.J., "Facilitating Program Comprehension by Mining Association Rules from Source Code", Proc. IEEE 11th Int’l Workshop Program Comprehension (IWPC 03), pp. 125-132 (2003) • Conference Paper
• Tjortjis C, Dafoulas G., Layzell P.J., Macaulay L. and , "A Model for Selecting CSCW Technologies for Distributed Software Maintenance Teams in Virtual Organisations", Proc. IEEE 26th Int’l Computer Software Applications Conf. (COMPSAC 02), pp. 1104-1108 (2002) • Conference Paper
• Tjortjis C., Gold N., Layzell P.J. and Bennett K., "From System Comprehension to Program Comprehension", Proc. IEEE 26th Int’l Computer Software Applications Conf. (COMPSAC 02), pp. 427-432 (2002) • Conference Paper
• Tjortjis C. and Layzell P.J., "Expert Maintainers’ Strategies and Needs when Understanding Software: A Qualitative Empirical Study", Proc. IEEE 8th Asia-Pacific Software Engineering Conf (APSEC 2001), pp. 281-287 (2001) • Conference Paper