Welcome!

Hello! I am Grigorios (Gregory) Tzortzis. My research interests include machine learning, data mining, bioinformatics, semantic web and Internet of Things. In 2014 I received my PhD in machine learning from the Computer Science & Engineering Department, University of Ioannina, Greece. I have also received my BSc and MSc in computer science from the same institution in 2006 and 2008, respectively. I am a motorsport aficionado, I like Formula 1 and WRC. I also enjoy model building.
For a complete list of my latest endeavors visit my LinkedIn profile.

Publications & Software

Journals

Marianna Sakka, Grigorios Tzortzis, Michalis D. Mantzaris, Nick Bekas, Tahsin F. Kellici, Aristidis Likas, Dimitrios Galaris, Ioannis P. Gerothanassis, Andreas G. Tzakos, PRESS: Protein S-sulfenylation Server , Bioinformatics, vol. 32, no. 17, pp. 2710-2712, 2016
Grigorios Tzortzis, Aristidis Likas, The MinMax K-Means Clustering Algorithm, Pattern Recognition, vol. 47, no. 7, pp. 2505-2516, 2014
Grigorios Tzortzis, Aristidis Likas, Multiple View Clustering Using a Weighted Combination of Exemplar-based Mixture Models, IEEE Trans. on Neural Networks, vol. 21, no. 12, pp. 1925-1938, 2010
Grigorios Tzortzis, Aristidis Likas, The Global Kernel K-Means Algorithm for Clustering in Feature Space, IEEE Trans. on Neural Networks, vol. 20, no. 7, pp. 1181-1194, 2009

Conferences

Ilias Sarantopoulos, Dimitrios Papatheodorou, Dimitrios Vogiatzis, Grigorios Tzortzis, Georgios Paliouras, TimeRank: a RandomWalk approach for Community Discovery in Dynamic Networks, Int. Conf. on Complex Networks and Their Applications (COMPLEX NETWORKS), pp. 338-350, 2018
George Athanasopoulos, George Paliouras, Dimitrios Vogiatzis, Grigorios Tzortzis, Nikos Katzouris, Predicting the Evolution of Communities with Online Inductive Logic Programming, Int. Symposium on Temporal Representation and Reasoning (TIME), pp. 4:1-4:20, 2018
Georgios Kechagias, Grigorios Tzortzis, Dimitrios Vogiatzis, George Paliouras, A Parallel Algorithm for Tracking Dynamic Communities based on Apache Flink, Hellenic Conf. on Artificial Intelligence (SETN), pp. 9:1-9:4, 2018
Charilaos Akasiadis, Grigorios Tzortzis, Evaggelos Spyrou, Constantine Spyropoulos, Developing Complex Services in an IoT Ecosystem, IEEE World Forum on Internet of Things (WF-IoT), pp. 52-56, 2015
Grigorios Tzortzis, Aristidis Likas, Ratio-based Multiple Kernel Clustering, European Conf. on Machine Learning (ECML/PKDD), vol. 3, pp. 241-257, 2014
Grigorios Tzortzis, Aristidis Likas, Kernel-based Weighted Multi-view Clustering, Int. Conf. on Data Mining (ICDM), pp. 675-684, 2012
Grigorios Tzortzis, Aristidis Likas, Greedy Unsupervised Multiple Kernel Learning, Hellenic Conf. on Artificial Intelligence (SETN), pp. 73-80, 2012
Grigorios Tzortzis, Aristidis Likas, Convex Mixture Models for Multi-view Clustering, Int. Conf. on Artificial Neural Networks (ICANN), vol. 2, pp. 205-214, 2009
Grigorios Tzortzis, Aristidis Likas, The Global Kernel K-Means Clustering Algorithm, Int. Joint Conf. on Neural Networks (IJCNN), pp. 1978-1985, 2008
Grigorios Tzortzis, Aristidis Likas, Deep Belief Networks for Spam Filtering, Int. Conf. on Tools with Artificial Intelligence (ICTAI) vol. 2, pp. 306-309, 2007

Workshops

Maria Evangelia Pavlopoulou, Grigorios Tzortzis, Dimitrios Vogiatzis, George Paliouras, Predicting the Evolution of Communities in Social Networks Using Structural and Temporal Features, Int. Workshop on Semantic and Social Media Adaptation and Personalization (SMAP), pp. 40-45, 2017
Grigorios Tzortzis, Evaggelos Spyrou, A Semi-Automatic Approach for Semantic IoT Service Composition, Workshop on Artificial Intelligence and Internet of Things (AI-IoT) in conjunction with SETN 2016, 2016

Book Chapters

Grigorios Tzortzis, Charilaos Akasiadis, Evaggelos Spyrou, Semantic Complex Service Composition within an IoT Ecosystem, The Internet of Things: Foundation for Smart Cities, eHealth, and Ubiquitous Computing, Chapman and Hall/CRC, pp. 151-172, 2017, DOI: https://doi.org/10.1201/9781315156026-10

Dissertations

Grigorios Tzortzis, Clustering Using Similarity and Kernel Matrices, PhD Thesis (supervisor: Aristidis Likas), 2014
Grigorios Tzortzis, Efficient Kernel-based Clustering, MSc Thesis (supervisor: Aristidis Likas), 2008
Grigorios Tzortzis, Content-based classification of e-mail messages, BSc Thesis (supervisor: Aristidis Likas), 2006

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