- Project Leader, “Bidline Generation System”, resulted in estimated savings annually of USD $44 million.
- Technical Manager, “ARCHEOGUIDE” EU IST program.
- Project Manager, “Activity-based Budgeting and Planning Information System”, consultant for ΔΕΗ Α.Ε.
- Technical Manager, “Porting JME Mobile Applications”.
- Technical Manager, “Greek Business Network Site for INFOTE S.A”.
- Project and Technical Manager, “Fraud Detection in Games of Chance”
- Project and Technical Manager, “AMORE: Movie Recommendation System for Triple Play Services Providers”
- Participation and Technical Leadership in EU IST Projects ELeGI, DESEREC, INMOTOS
- Business Intelligence, Optimization Methods in Data Mining, Machine Learning and Supply Chain Management, Intelligent Information Retrieval
INTERNATIONAL (European) PROJECTS
ONGOING AND RECENT INDUSTRIAL PROJECTS
- Ait MOvie Recommendation Engine (AMORE): Automatic Content Recommendation for Subscribers to Triple-Play Services. AMORE is the first movie recommender system to be commercially deployed in Greece (since Jan. 2013, by Triple-Play provider Hellas On Line S.A.)
- Responsible Gaming: Detecting possible addictive behavior in players’ gambling history
- Eyes-On: Fraud Detection in Games of Chance
- IDM: Light-weight Identity Management
- AIT Content Management System
Parallel/Distributed Optimization: POPT4JLIB is an Open-Source parallel/distributed optimization meta-heuristic library exploiting to the fullest extent the multiple cores found in today’s laptops, PCs and servers, and the power of clusters of networked computers. The current version includes a rich and robust implementation of most important parallel and distributed programming APIs (for many-core networked computers) including shared memory primitives such as locks, semaphores, condition-counters, barriers, thread-pools, limited-time task executors, message passing, etc. as well as distributed memory task executors, distributed locks, barriers, message passing coordinators etc. The library uses these primitives to build on top, robust multi-threaded implementations of Genetic Algorithms, Simulated Annealing, Evolutionary Algorithms, Differential Evolution, Monte-Carlo Search, Local Search, and Gradient-Descent algorithms for nonlinear optimization -including Newton-type algorithms as well as non-Newton type algorithms, as well as some standard optimization algorithms on graphs and vector spaces (parallel implementation of the Bron-Kerbosch algorithm for detecting all cliques in a graph, Dijkstra’s algorithms for the Shortest Path Problem, parallel hybrid algorithms for packing and 2-packing problems on graphs, graph and hyper-graph coarsening and multi-level partitioning algorithms, parallel implementation of the hard K-Means algorithm for Minimum-Sum-of-Square-errors-Clustering including KMeans++ initialization of seeds etc.) The next version (to be released in the next few months) will include parallel linear network optimization (the network simplex method) as well as parallelized auction algorithms for assignment and transhipment problems, and others. The library is released by me (the sole author) under the GNU LGPL and can be compiled with JDK 1.4 and above, and run with JRE 1.4 or higher!. A pre-compiled jar file is included in the distribution, together with some batch files for executing the various algorithms, along with various test-data. See the included javadoc documentation for more details and instructions on how to use the library.
Decision Support Systems and Optimization: MATLAB code for (r,nQ,T) and (s,S,T) periodic review policy optimization (exact and heuristic methods)
Clustering Optimization: Java code for Minimum Sum of Squares Clustering (MSSC) using a Set Covering formulation to coordinate cluster ensembles. (You must separately download the open-source SCIP solver. It is recommended to simply download the binary file)
Data Mining and Machine Learning: SVM_ODT Java code for a hybrid Decision Tree that considers Support Vectors when branching (the code is embedded within the free Open Source WEKA framework, and is released together with WEKA version 3.5 as an eclipse project)
Ioannis T. Christou, Quantitative Methods in Supply Chain Management: Models and Algorithms, Springer Engineering, 2011. See a book review in the Production Planning and Control journal here. Another review at the INFORMS Interfaces journal here
See Google Scholar link for my publications and citations to them.
- E. Amolochitis, I.T. Christou, Z.-H. Tan, ” Implementing a Commercial-Strength Parallel Hybrid Movie Recommendation Engine”, IEEE Intelligent Systems, 2014. To Appear.
- I.T. Christou, S. Vasillaras, “A Parallel Distributed Hybrid GRASP and Branch & Bound Scheme for the Maximum Distance-2 Matching Problem”, Computers & Operations Research, 40, 2013, pp. 2387-2397
- E. Amolochitis, I.T. Christou, Z.-H. Tan, R. Prasad, A Heuristic Hierarchical Scheme for Academic Search and Retrieval, Information Processing & Management, 49, 2013, pp. 1326-1343.
- S. Ponis, I.T. Christou, “Enhancing SME’s Competitive Intelligence: a Web-based Decision Support System Architecture”, Intl. Journal of Business Information Systems, 12(3), 2013, pp. 243-258.
- P. Spanos, S. Ponis, I. Tatsiopoulos, I.T. Christou, E. Rokou “A New Hybrid Parallel Genetic Algorithm for the Job-Shop Scheduling Problem”, Intl. Transactions in Operational Research, To Appear, Sep. 2013.
- I.T. Christou, G. Gekas, A. Kyrikou, A Classifier Ensemble Approach to the TV-Viewer Profile Adaptation Problem, Intl. Journal of Machine Learning and Cybernetics, vol. 3, no. 4, 2012, pp. 313-326, DOI: 10.1007/s13042-011-0066-4.
- A.G. Lagodimos, I.T. Christou, K. Skouri, Computing Globally Optimal (s,S,T) Inventory Policies, OMEGA: The International Journal of Management Science, vol. 40, no. 5, Oct. 2012, pp. 660-671.
- A.G. Lagodimos, I.T. Christou, K. Skouri, Optimal (r,nQ,T) Batch Ordering with Quantized Supplies, Computers & Operations Research, vol. 39, no. 2, 2012, pp. 259-268.
- I.T. Christou, M. Bakopoulos et al, Detecting Fraud in Online Games of Chance and Lotteries, Expert Systems with Applications, vol. 38, no. 10, 2011, pp. 13158-13169
- A.G. Lagodimos, I.T. Christou, K. Skouri, Optimal (r,nQ,T) Policies under Stationary Demand, Intl. Journal of Systems Science, 43(9), 2012, pp. 1774-1784. DOI: DOI:10.1080/00207721.2011.555010. Published online, 17 Feb. 2011
- Ioannis T. Christou, “Coordination of Cluster Ensembles via Exact Methods”, IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 33, no. 2, 2011. Published online, 30 Mar. 2010, IEEE computer Society Digital Library. IEEE Computer Society, DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/TPAMI.2010.85., pp. 279-293.
- K. Mourtzoukos, I.T. Christou, S. Efremidis, “Experiences with G2G: a location-aware mobile social networking system”, Intl. Journal of Pervasive Computing and Communications, 7(2), pp. 98-113, 2011.
- Ioannis T. Christou et. al., “Grid-based Interactive Virtual Experiments for Distributed Virtual Communities”, Intl. Journal on Continuous Engineering Education & Life-long Learning, vol. 20, no. 6, 2010, pp. 443-464
- Ioannis T. Christou, S. Efremidis, A. Roukounaki, A CASE Tool for Java Mobile Computing Applications, Intl. Journal of Mobile Computing and Multimedia Communications, vol. 2, no. 2, 2010, pp. 34-48
- Ioannis T. Christou and S. Michalakos, “G2G: Location-aware Mobile Social Networking with Application in Personalized Recommender Systems”, Journal of Mobile Multimedia, vol 6, no. 1, March 2010, pp. 73-94
- Ioannis T. Christou, S. Ponis, E. Palaiologou, Using the Agile Unified Process in Banking, IEEE Software, vol. 27 no. 3, May-June 2010, pp. 72-79
- Ioannis T. Christou and Stavros Ponis, “A Hierarchical System for Efficient Coordination of Available-To-Promise Logic Mechanisms”, International Journal of Production Research, vol. 47, no. 11, 2009, pp. 3063-3078. Online version first published March 2008.
- Ioannis T. Christou and S.T. Ponis, “Enhancing Traditional ATP Functionality in Open Source ERP Systems: A Case-Study from the Food & Beverages Industry”, Intl. Journal of Enterprise Information Systems, vol. 4, no. 1, 2008, pp. 18-33
- S.T. Ponis, I.P. Tatsiopoulos, K.C. Tsitsiriggos, and Ioannis T. Christou, “Integrating Enterprise Resource Planning vendor evaluation into a proposed ERP selection methodology”, Intl. Journal of Integrated Supply Management, vol. 3, no. 4, 2007, pp. 364-384.
- Ioannis T. Christou, Athanasios G. Lagodimos, and Dimitra Lycopoulou, “Hierarchical Production Planning for Multi-product Lines in the Beverage Industry”, Production Planning and Control, vol. 18, no. 5, Jul. 2007, pp. 367-376
- Ioannis T. Christou et. al., “GRID-based Virtual Laboratory Experiments for a Graduate Course on Sensor Networks”, IEEE Transactions on Education, vol. 50, no. 1, Feb. 2007, pp. 17-26. Special issue on “Grid-based Technologies Applied to Education”.
- D. Papageorgiou, N. Ioannidis, I. T. Christou, M. Papathomas and M. Diorinos, “ARCHEOGUIDE: An Augmented Reality based System for Personalized Tours in Cultural Heritage Sites”, Cultivate Interactive, Issue 1, Jun. 2000. (Electronic journal publication: http://www.cultivate-int.org/issue1/archeo/ )
- Ioannis T. Christou, Armand Zakarian, Jun-Min Liu and Helen Carter, “A Two Phase Genetic Algorithm for Solving Large Scale Bid-Line Generation Problems”, Interfaces, vol. 29, no. 5, Sep 1999, pp. 51-65. Special issue on finalist papers for the Daniel H. Wagner Prize.
- Ioannis T. Christou, Wayne Martin, and Robert R. Meyer, “Genetic Algorithms as Multi-Coordinators in Large Scale Optimization”, Institute for Mathematics and its Applications, vol. 111 – Evolutionary Algorithms, Springer-Verlag, 1999, pp. 1-15. Also Proc. of Evolutionary Algorithms Workshop, eds. L.D. Davis, L.D. Whitley, K. DeJong and M. Vose,1999.
- Ioannis T. Christou, William W. Donaldson and Robert R. Meyer, “Large Scale Structured Discrete Optimization via Parallel Genetic Algorithms”, Institute for Mathematics and its Applications, vol. 109 – Parallel Processing of Discrete Problems, Springer-Verlag, 1998.
- Jonathan Yackel, Robert R. Meyer and Ioannis T. Christou, “Minimum Perimeter Domain Assignment”, Math. Programming, vol. 78, no 2, pp. 283-303, Aug. 1997.
- Ioannis T. Christou and Robert R. Meyer, “Optimal Equi-partition of Rectangular Domains for Parallel Computation”, Journal of Global Optimization, vol. 8, pp. 15-34, Jan. 1996.
Submitted Journal Publications pending review
- I.T. Christou, A.G. Lagodimos, K. Skouri, “Fast Heuristic Global Optimization of Stochastic Inventory Control Policies”, submitted to European Journal of Operational Research, under revision.
Book Chapter Publications
- C. Manolarakis, I.T. Christou, G. Yovanof, Avoiding Risks Related with Strategic Pricing in Virtual Enterprise Networks: An Agent-based Approach, in S. Ponis (ed.): Managing Risk in Virtual Enterprise Networks: Implementing Supply Chain Principles, IGI Global, Hershey, NY, 2010. DOI: 10.4018/978-1-61520-607-0.ch014.
- Ioannis T. Christou et. al., “Grid-based Interactive Virtual Experiments for Distributed Virtual Communities”, in The Learning Grid Handbook, eds. Saverio Salerno et. al., IOS Press, 2008.
- Stefanos Koutsoutos, Ioannis T. Christou, and Sofoklis Efremidis, “A Classifier Ensemble Approach to Intrusion Detection for Network-Initiated Attacks”, invited contributed chapter in Emerging Artificial Intelligence Applications in Computer Engineering, eds. John Soldatos et al, IOS Press, 2007.
- Ioannis T. Christou and Robert R. Meyer, “Decomposition Algorithms for Communication Minimization in Parallel Computing”, invited contributed chapter in Non-Linear Assignment Problems: Theory & Applications, ed. Panos Pardalos and Leo Pitsoulis, Kluwer Academic Publishers, 2000.
- Ioannis T. Christou and Robert R. Meyer, “Optimal and Asymptotically Optimal Equi-partition of Rectangular Domains via Stripe Decomposition”, in Applied Mathematics and Parallel Computing – Festchrift for Klaus Ritter, eds. H. Fischer, B. Riedmuller, and S. Schaffler, pp. 77-96, Physica-Verlag, 1996.
Peer-reviewed Conference Publications
- N. Goumatianos, Ioannis T. Christou, P. Lindgren, Stock Selection System: Building Long/Short Portfolios Using Intraday Patterns, Proc. Intl. Conf. on Applied Economics (ICOAE 2013), Istanbul, Turkey, June 2013. Published on Elsevier Procedia in Economics and Finance.
- N. Goumatianos, Ioannis T. Christou, P. Lindgren, Useful Pattern Mining on Time Series: Applications in the Stock Market, Proc. 2nd Intl Conf. on Pattern Recognition Applications and Methods (ICPRAM 2013), Barcelona, Spain, Feb. 15-18, 2013.
- M. Barbieri, I.C. Bertolotti, M. Cheminod, Ioannis T. Christou, L. Durante, S. Efremidis, G. Gentile, P. Kieseberg, S. Lehmann, P. Paci, M. Pesce, A. Ronge, M. Tanas, C. Taverner, L. Zechner, The INMOTOS Project, Proc. 7th Intl. Workshop on Critical Information Infrastructure (CRITIS 2012), Sep. 17-18, 2012, Lillehammer, Norway, 2012.
- E. Amolochitis, I.T. Christou, Z.-H. Tan, PubSearch: A Hierarchical Heuristic Scheme for Ranking Academic Search Results, Proc. 1st Intl Conf. on Pattern Recognition Applications and Methods (ICPRAM 2012), Vilamura, Argave, Portugal, Feb. 6-8, 2012.
- S. Vassilaras, I.T. Christou, On the Optimal MAC Layer Capacity of Delay Tolerant Mobile Ad-Hoc Networks with a Finite Number of Nodes, Proc. IEEE Conf. on Personal, Indoor and Mobile Radio Communications 2011 (PIMRC 2011), Sep. 11-14, Toronto, Canada.
- A.G. Lagodimos, I.T. Christou, K. Skouri, A Simple Procedure to Determine Optimal (s,S,T) Inventory Policy under Stationary Demand, Proc. Challenges in Statistics and Operations Research Conference, Kuwait, Mar. 2011.
- K. Mourtzoukos, I.T. Christou, Experiences Running G2G: A Prototype Location-aware Mobile Social Networking System, ACM 8th Intl. Conference on Advances in Mobile Computing and Multimedia, MoMM 2010, Paris, France, Nov. 2010.
- A.G. Lagodimos, I.T. Christou, K. Skouri, Optimal (r,nQ,T) Inventory Control under Stationary Demand, Proc. 3rd Meeting of the EURO Working Group on Stochastic Modeling, StochMod 2010, June 7-9, 2010, Nafplio, Greece.
- C. Manolarakis, Ioannis T. Christou, G. Yovanof, “Mapping Consumer Perception and Market Distribution of Consumer Products Using Agent-based Modeling”, Intl. Congress on Pervasive Computing & Management, New Delhi, India, Dec. 2008.
- S. Michalakos and Ioannis T. Christou, “G2G: Location-aware Mobile Social Networking with Applications in Recommender Systems and Gaming”, ACM 6th Intl. Conference on Advances in Mobile Computing and Multimedia, MoMM 2008, Linz, Austria, Nov. 2008.
- V. Menkovski, Ioannis T. Christou, and S. Efremidis, “Oblique Decision Trees using Embedded Support Vector Machines in Classifier Ensembles”, IEEE Cybernetic Intelligent Systems Conf., London, UK, Sep. 2008.
- S. Tsekeridou, T. Tiropanis, Ioannis T. Christou, and H. Vakilzadeh, “Toward Virtual Campuses: Collaborative Virtual Labs & Personalized Learning Services in a Real-life Context”, IASTED Web-based Education Conference, Innsbruck, Austria, Mar. 2008.
- Ghassan Karame, Ioannis T. Christou and Tassos Dimitriou, “A Secure Hybrid Reputation Management System for Super-Peer Networks”, 5th IEEE Consumer Communications and Networking Conference (IEEE-CCNC), Las Vegas, NV, USA, Jan. 2008.
- Tassos Dimitriou, Ghassan Karame, and Ioannis T. Christou, “SuperTrust: A Secure and Efficient Framework for Handling Trust in Super Peer Networks”, IEEE CDNC, India, Jan. 2008.
- Ioannis T. Christou & Sofoklis Efremidis, “An Evolving Oblique Decision Tree Ensemble Architecture for Continuous Learning Applications”, 4th IFIP Intl. Conference on Artificial Intelligence Applications and Innovations, Athens Greece, Sep. 2007.
- Ioannis T. Christou, Sofoklis Efremidis, Aikaterini Roukounaki & Marios Anapliotis, “An Intelligent CASE Tool for Porting Mobile Java Applications”, 4th IFIP Intl. Conference on Artificial Intelligence Applications and Innovations, Athens Greece, Sep. 2007.
- Tassos Dimitriou, Ghassan Karame, and Ioannis T. Christou, “SuperTrust: A Secure and Efficient Framework for Handling Trust in Super Peer Networks”, ACM SIGACT-SIGOPT Conf. on Principles of Distributed Computing (ACM PODC) Brief Announcement, 2007.
- Ioannis T. Christou, and Spyridon Potamianos, “A Distributed Planning & Control Management Information System for Multi-site Organizations”, Intl. Conf. on Computing Sciences and Software Engineering CISSE 06, Univ. of Bridgeport, Dec. 2006.
- Anna Pieri, Thanassis Tiropanis, Ioannis T. Christou, Sofia Tsekeridou and Bill Vassiliadis, “Application of a Virtual Scientific Experiment Model in Different Educational Contexts”, e-challenges e-2006 Conf., Barcelona, Spain, Oct. 2006. Published in “Exploiting the Knowledge Economy: Issues, Applications, Case Studies”, Paul Cunningham and Miriam Cunningham (Eds), IOS Press, 2006 Amsterdam, ISBN: 1-58603-682-3
- Stefanos Koutsoutos, Ioannis T. Christou, and Sofoklis Efremidis, “An Intrusion-Detection System for Network-Initiated Attacks Using a Hybrid Neural Network”. 3rd IFIP Intl. Conference on Artificial Intelligence Applications and Innovations, Athens Greece, May 2006.
- Ioannis T. Christou, “Load-Balancing Issues in Super-peer-based Pub/Sub Digital Libraries”, Proc. of the 5th IEEE International Conference on Peer-To-Peer Computing, Constanz, Germany, Sep. 2005.
- Vasilios Vlahakis, John Karigiannis, Manolis Tsotros, Michael Gounaris, Luis Almeida, Didier Stricker, Tim Gleue, Ioannis T. Christou, Renzo Carlucci, Nikos Ioannidis, “ARCHEOGUIDE: First Results from an Augmented Reality, Mobile Computing System in Cultural Heritage Sites”, Proc. of ACM SIGGRAPH Intl. Conference on Computer Graphics and Interactive Techniques VAST 2001: “Virtual Reality, Archaeology, and Cultural Heritage”, pp. 131-140, ACM Press, Athens, Greece, Nov.2001.
- Didier Stricker, John Karigiannis, Ioannis T. Christou, Tim Gleue, Nikos Ioannidis, “Augmented Reality for Visitors of Cultural Heritage Sites”, Proc. of CAST 2001: Intl. Conf. on Artistic, Cultural & Scientific Aspects of Experimental Media Spaces, Bonn, Germany, Sep. 2001.
- Didier Stricker, Patrick Daehne, Frank Seibert, Ioannis T. Christou, Luis Almeida, Renzo Carlucci and Nikos Ioannidis: “Design & Development Issues in ARCHEOGUIDE: An Augmented Reality based Cultural Heritage On-site Guide”, Proc. of the Intl. Conf. on Augmented Virtual Environments and 3D Imaging (EuroImage 2001), pp. 1-7,IEEE Press, Myconos, Greece, May 2001.
- Ioannis T. Christou and Armand Zakarian, “Domain Knowledge and Representation Issues in Genetic Algorithms for Scheduling Problems”, Proc. of the Genetics and Evolutionary Computation Conference 2000 (GECCO 2000), pp. 681-687, Morgan-Kaufmann Press, Las Vegas, Jun. 2000.
- Ioannis T. Christou and Robert R. Meyer, “Fast Distributed Genetic Algorithms for Partitioning Uniform Grids”, Proc. of the 3rd International Workshop on Parallel Algorithms for Irregularly Structured Problems (Irregular 96). Lecture Notes in Computer Science vol. 1117, Springer-Verlag 1996.
- Spyros Tzafestas, Paraskevas Dalianis and Ioannis T. Christou, ” Diagnosis of Multiple Simultaneous Faults in Complex Systems: An Expert System Implementation for the Automotive Domain”, Proc. of the 1st European Congress on Fuzzy and Intelligent Technologies, Aachen, Germany, 1993.
- Spyros Tzafestas, Ioannis T. Christou and Y.-J. Yip, Multiple Fault Diagnosis of Digital Circuits Using Non-monotonic Reasoning, Proc. of the 31st IEEE Conf. on Decision and Control, Corfu, Greece, 1991.
- Ioannis T. Christou, ” Distributed Genetic Algorithms for Partitioning Uniform Grids”, Ph.D. thesis, UW-Madison, Comp. Sci. Tech. Report MP-TR-96-09. Madison, Wisconsin, 1996.
- Ioannis T. Christou, “Graph-based Algorithms for Linked-Data Clustering”.
INVITED LECTURES / CHAIRED SESSIONS / PANELS
“Το Συμμετοχικό Διαδίκτυο και οι Ανθρώπινες Σχέσεις”, ομιλία και συμμετοχή σε panel, ATHENS DIGITAL WEEK, Oct. 2008, Athens Technopolis Center, Gkazi, Athens Greece
chair: Technical Session “Location & Context Aware Applications”, 6th Intl. Conference on Advances in Mobile & Multimedia Computing Systems, Nov. 2008, Linz, Austria (MoMM 2008)
CONFERENCE/ SYMPOSIUM / WORKSHOP ORGANIZATION
Co-organizer, Intl. Conference on “Data Mining in Bio-medicine 2009”, May 7-8, 2009, Athens Greece.
Organized by Prof. Panos Pardalos, Prof. Damianos Sakas, Prof. Ioannis T. Christou
C. Dimitriadis, I.T. Christou, M. Bakopoulos: METHODS AND A SYSTEM FOR DETECTING FRAUD IN BETTING AND LOTTERY GAMES. Patent Filed with the US Patents and Trademark Office on May 25, 2010 assigned patent application serial no. 12/787,024. Patent Published.
ACM, IEEE, Technical Chamber of Greece
Nominated for the 1999 Daniel H. Wagner Award in Excellence in Operations Research Practice
EDITORIAL WORK / PAPER REVIEWING
Referree for IEEE Transactions on Pattern Analysis and Machine Intelligence, IEEE Transactions on Evolutionary Computation, IEEE Transactions on Data & Knowledge Engineering, IEEE Transactions on Systems, Man and Cybernetics Part A, Omega Journal, Supply Chain Management: an International Journal, Journal of Systems and Software, Computational Intelligence, European Journal of Operational Research etc.