Foto Afrati

Professor
National Technical Universtity of Athens
School of Electrical and Computing Engineering
Division of Communication, Electronic and Information Engineering
Zographou Campus
Iroon Polytechniou 9
15780 Athens, Greece

E-mail: afrati AT softlab. ece. ntua. gr
Phone: +30-210-7722498 (Office)
Fax: +30-210-7722499
Office: 1.1.14
Building: Electrical and Comp. Engineering, Floor 1

Research Interests

Information integration
Data and web mining
Database theory
Query languages
Approximation algorithms
Constraint databases
Finite model theory
Scheduling

Brief Biography

Education

3/80 PhD in Electrical Engineering, Imperial College of the University of London. Thesis: Error Correcting Codes by Algorithms.
3/80 Diploma of Imperial College.
6/76 Diploma in Electrical and Mechanical Engineering, National Technical University of Athens, Greece.

Professional Appointments

5/93 to present : Professor of Computer Science, National Technical University of Athens, Greece.
9/89 to 5/93 : Associate Professor of Computer Science, NTU of Athens, Greece.
9/85 to 9/89 : Assistant Professor of Computer Science, National Technical University of Athens, Greece.
9/82 to 8/85 : Lecturer of Computer Science, NTU of Athens, Greece.
9/80 to 8/82 : Research Fellow, Electrical Engineering Dept., NTU of Athens, Greece.

Visiting Positions

February 2008 Visiting Stanford University
February 2007 Visiting IBM Research Center at Almaden
Winter 2005 Visiting the University of Helsinki
Summer 2005 Visiting Stanford University
February 2004 Visiting Stanford University
Spring 2000 Visiting Stanford University
Fall, Winter 1999-2000 Visiting in the University of Paris at Orsay
June 1999 Visiting University of Paris at Jussieu
May 1996 : Visiting Researcher at DIMACS
Winter 93-94 : Visiting Professor at the University of Paris
4/88 to 8/88 : Visiting Researcher at IBM Thomas J. Watson Research Center in Yorktown Heights, New York
1/88 to 3/88 : Visiting Assistant Professor, Dept. of Computer Science, Stanford University
3/88 : Visiting the Computer Science Dept., University of California at San Diego
10/87 to 12/87 : Visiting Assistant Professor, Dept. of Computer Science, Brown University
1/86 to 3/86 : Visiting Assistant Professor, Dept. of Computer Science, Stanford University

Professional Activities

Boards and Chair of Conferences

Member of the evaluation committee of Electrical and Computer Engineering & Informatics Technologies Department of Cyprus Univdersity of Technology 2008
Member of the Executive Committee of ACM Conference ``Principles of Database Systems'' (PODS) 2005-2007
Program Committee Chair of ACM Conference ``Principles of Database Systems'' (PODS) 2005
Program Committee Chair and Organizing Committee chair of ``International Conference on Database Theory'' (ICDT) 1997
Programm committee Chair of the Second workshop of Compulog Network network of excellence 1993

Program Committee member

VLDB 2007 - 33rd Very Large Data Bases Conference

ACM Conference ``Principles of Database Systems'' (PODS 2008)
Eleventh International Database Engineering Applications Symposium IDEAS07
First International Workshop on Web Mining for E-commerce and E-services WMEE07
Twelfth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining KDD06
20th International Conference on Data Engineering ICDE04
PODS 2001
PODS 2003
``International Conference on Database Theory'' (ICDT 2003)
PODS 1992
ICDT 1992
Second workshop of Compulog Network network of excellence 1993

Organizing Committee member

IEEE Communication Theory Workshop 1991
ICALP 1985
IEEE Conference MELECON 1983

Other Professional Activities

Member of the Technical Chamber of Greece, the Greek Mathematical Society, the Greek Computer Science Association, and the European Association for Theoretical Computer Science
Member of the Committee for higher education of the Technical Chamber of Greece
PhD thesis committees: University of Paris, Stanford, Hebrew University (Sara Cohen), numerous in Greece
Member of the reading committee for the PhD theses of Chen Li, Stanford University, 2001
She has been invited and give talks at IBM J. Watson Research Center, Bell Laboratories, Courant Institute of New York University, University of Pennsylvania, Stanford University, Imperial College, Universite Paris XI, VI, INRIA Rocquenqourt

Research Projects

Projects funded by the European Union

COMPULOG 1992-
"Query answering and schema mapping composition in data exchange framework", Scientific and Technological cooperation between Greece and USA (in cooperation with Chen Li, University of California, Irvine), [1/2006-12/2007]
APPOL (on Approximation Algorithms) 1999- 2003
ESF network which involved "Anatomy and Gene expression Database'" 1993-1995
ESPRIT working group on Constraint Databases (CONTESSA) 1994-1997
PLATO: Greek - French cooperation program on Parallel Algorithms 1996 - 1997
Partner in HCM network in the area of "Logic Program Synthesis and Transformation" 1993-1996
Host for HCM grant holder on Scheduling 1995-1996
Bilateral French-Greek project on Scheduling 1995-1998
Bilateral British-Greek project on Databases 1998-1999

Projects funded by the Greek General Secreteriat of Research and Technology

Graduate Program in Logic, Algorithms and Computation (MPLA) 1998-
"Data integration in heterogeneous Web sources and peer-to-peer networks", Ministry of Development, Greek Secretariat of Research and Technology, "PENED 2003", [12/2005 - 12/2008]
"Query optimization in heterogeneous databases and distributed systems", Operational Programme for Educational and Vocational Training (EPEAEK), European Social Fund: "Pythagoras II", [3/2005 - 3/2007]
Approximation Algorithms and Indexing Sampling Methods for Data Mining in Web, Operational Programme for Educational and Vocational Training (EPEAEK), European Social Fund: "Pythagoras I", 2004-2007
"Query reformulation and optimization for information retrieval in data exchange and data integration settings: algorithms and semantic reasoning", Operational Programme for Educational and Vocational Training (EPEAEK), European Social Fund: "Herakleitos", [11/2002-4/2005]
Sampling Techniques for Data Mining, 2004-2005
XML and Semistructured Data, 2003-2005
Webminer - Support for decisions in Micro-economic managment using Data Mining and Optimization techniques (PENED99),1999-2001
Scheduling Algorithms for Optical Networks, General Secretariat for Research and Technology, 1998-2001
Partner in the ``Graduate Studies Program on Logic and Algorithms'' 1998-
Principles and methods of artificial intelligence linking Object-Oriented with Deductive databases 1996-1998
Object Oriented Databases (1995-1997)
Knowledge Bases: Representation, Processing and assimilation of knowledge 1993-1995
Parallel Processing for database query languages 1993-1995
Logic programming(1990-1992)
Theory of databases(1985-1987)
Algorithms and Computational Complexity(1985-1987)

PhD Students

Graduated PhD students

Mitakos, graduated 1998
Hattab, graduated 2003
Al Said, graduated 2004
Lekeas, graduated 2005
Kontopantelis, graduated 2005
Pavlaki, graduated 2006

Current PhD students

Timos Aslanidis
Matthew Damigos
Giannis Delveroudis
Nikos Kiourtis
Victor Kyritsis
Angelos Vasilakopoulos

Post Docs

Current

Pavlaki, graduated 2006

Alumni

Milis 1996--1999, Associate Professor at AUEB
Gergatsoulis 1997--1999, tenured Assistant Professor at Ionian University
Andronikos 1998--2001, Assistant Professor at Ionian University
Foustoucos 1999--2001, Lecturer at MPLA

Publications

My DBLP entry.

2008

Foto N. Afrati, Matthew Damigos, Manolis Gergatsoulis : On solving efficiently the View Selection Problem under Bag-semantics. 2nd International Workshop on Business Intelligence for the Real Time Enterprise (BIRTE 2008) (in conjunction with the VLDB 2008 Conference), Auckland, New Zealand, August 24, 2008
Foto N. Afrati, Nikos Kiourtis: Query Answering using Views in the Presence of Dependencies. International Workshop on New Trends in Information Integration (NTII 2008) (in conjunction with the VLDB 2008 Conference), Auckland, New Zealand, August 23, 2008
Foto N. Afrati, Chen Li, Vassia Pavlaki Data Exchange: Query Answering for Incomplete Data Sources (pdf format). Infoscale 2008
Foto N. Afrati, Chen Li, Vassia Pavlaki: Data exchange in the presence of arithmetic comparisons. EDBT 2008: 487-498
Foto N. Afrati, Phokion G. Kolaitis: Answering aggregate queries in data exchange. PODS 2008: 129-138
Foto N. Afrati, Paraskevas V. Lekeas, Chen Li: Adaptive-sampling algorithms for answering aggregation queries on Web sites. Data Knowl. Eng. 64(2): 462-490 (2008)

2007

Foto N. Afrati: Rewriting Conjunctive Queries Determined by Views. MFCS 2007: 78-89
Foto N. Afrati, Rada Chirkova, Manolis Gergatsoulis, Vassia Pavlaki: View selection for real conjunctive queries. Acta Inf. 44(5): 289-321 (2007)
Foto N. Afrati, Chen Li, Jeffrey D. Ullman: Using views to generate efficient evaluation plans for queries. J. Comput. Syst. Sci. 73(5): 703-724 (2007)

2006

Foto N. Afrati, Rada Chirkova, Manolis Gergatsoulis, Vassia Pavlaki: Finding Equivalent Rewritings in the Presence of Arithmetic Comparisons. EDBT 2006: 942-960
Foto N. Afrati, Jennifer Widom: Foreword to special section on SIGMOD/PODS 2005. ACM Trans. Database Syst. 31(4): 1417 (2006)
Foto N. Afrati, Vassia Pavlaki: Rewriting queries using views with negation. AI Commun. 19(3): 229-237 (2006)
Foto N. Afrati, Chen Li, Prasenjit Mitra: Rewriting queries using views in the presence of arithmetic comparisons. Theor. Comput. Sci. 368(1-2): 88-123 (2006)
Foto N. Afrati: On Approximation Algorithms for Data Mining Applications(.pdf format). Chapter in Book, in volume "Approximation Algorithms in Combinatorial Optimization" of the series Lecture Notes in Computer Science (Springer Verlag) no 3484, 2006. Eds: E. Bampis, K. Jansen, C. Kenyon.
Foto N. Afrati, I. Milis: Designing PTASs for MIN-SUM Scheduling Problems(.pdf format). Discrete Applied Mathematics, 2006

2005

Foto N. Afrati, E. Bampis, L. Finta and I. Milis: Scheduling trees with large communication delays on two identical processors. Journal of Scheduling, 2005
Foto N. Afrati, Stavros Cosmadakis, Eugenie Foustoucos: Datalog programs and their persistency numbers (.pdf format) ACM Transactions on Computational Logic (TOCL), 2005
Foto N. Afrati, Timos Aslanidis, Evripidis Bampis, Ioannis Milis :Scheduling in Switching Networks with Set-Up Delays. J. Comb. Optim. 9(1): 49-57 (2005)
Foto N. Afrati, Evripidis Bampis, Lucian Finta, Ioannis Milis :Scheduling trees with large communication delays on two identical processors. J. Scheduling 8(2): 179-190 (2005)
Foto N. Afrati, Paraskevas V. Lekeas, Chen Li: Answering aggregation queries on hierarchical web sites using adaptive sampling. CIKM 2005: 237-238
Foto N. Afrati, Rada Chirkova, Shalu Gupta, Charles Loftis: Designing and Using Views to Improve Performance of Aggregate Queries (Extended Abstract). DASFAA 2005: 548-554
Foto N. Afrati, Gautam Das, Aristides Gionis, Heikki Mannila, Taneli Mielikäinen, Panayiotis Tsaparas: Mining Chains of Relations. ICDM 2005: 553-556
Foto N. Afrati, Rada Chirkova: Selecting and Using Views to Compute Aggregate Queries (Extended Abstract). ICDT 2005: 383-397
Foto N. Afrati, Rada Chirkova, Manolis Gergatsoulis, Vassia Pavlaki: Designing Views to Efficiently Answer Real SQL Queries. SARA 2005: 332-346
Foto N. Afrati, Theodore Andronikos, Vassia Pavlaki, Eugénie Foustoucos, Irène Guessarian: On relating CTL to Datalog CoRR abs/cs/0510012: (2005)
Foto N. Afrati: Report on PODS 2005. SIGACT News 36(3): 39-40 (2005)

More Publications

Books

Afrati, F., "Introduction to Information Theory" (in greek), Symmetria, Athens, 1985.
Afrati, F., Papageorgiou, G., "Algorithms: Design and Analysis of Computational Complexity" (in greek), Symmetria, Athens, 1993, second edition with 25% new material, 2005.

Chapters in books

On Approximation Algorithms for Data Mining Applications, Foto Afrati. In the volume "Efficient Approximation and Online Algorithms" of the series Lecture Notes in Computer Science (Springer Verlag) no 3484, Eds: E. Bampis, K. Jansen, C. Kenyon, 2006.

Papers in Refereed Journals

16. Foto N. Afrati, Hans Leiß, Michel de Rougemont: Definability and Compression. Fundam. Inform. 56(1-2): 155-180 (2003)

15. Irène Guessarian, Eugénie Foustoucos, Theodore Andronikos, Foto N. Afrati: On temporal logic versus datalog. Theor. Comput. Sci. 1(303): 103-133 (2003)

14. Foto N. Afrati, Manolis Gergatsoulis, Francesca Toni: Linearizability on datalog programs. Theor. Comput. Sci. 308(1-3): 199-226 (2003)

13. Foto N. Afrati, Irène Guessarian, Michel de Rougemont: The expressiveness of DAC. Theor. Comput. Sci. 286(1): 3-32 (2002)

12. F. Afrati, E. Bampis, C. Kenyon and I. Milis, A PTAS for the average weighted completion time problem on unrelated machines, Journal of Scheduling 3 (2000) 323-332.

11. Afrati,F., "Bounded Arity Datalog (<>) Queries on Graphs" special issue of Journal of Computer and Systems Sciences, vol 55 1997 on ACM Conference 'Principles of Database Systems'.

10. Afrati, F., Cosmadakis, S.,Yannakakis, M., "Datalog vs. Polynomial Time", Journal of Computer and Systems Sciences (special issue on ACM Conference 'Principles of Database Systems'), October 1995.

9. Afrati,F., "A Polynomial Algorithm for Hamiltonian Grids". RAIRO Theoretical Informatics and Applications, Vol 28, no 6, 1994, pp 567-582.

8. Afrati, F., Stafylopatis, A., "Performance Considerations on a Random Graph Model for Parallel processing", RAIRO Theoretical Informatics and Applications, vol. 27, no. 4, 1993, pp 367-388.

7. Paschos, P., Anagnostou, M., Afrati, F., "Deterministic Access Protocols for Packet radio Networks", International Journal of Digital and Analog Communication Systems, Vol. 6 1993, pp. 151-160.

6. Afrati, F., Papadimitriou, C.H., "The Parallel Complexity of Simple Logic Programs", J.ACM, Vol. 90 No 4 September 1993, pp. 891-916.

5. Afrati, F., "The Parallel Complexity of Single Rule Logic Programs" . Discrtete Applied Mathematics (special issue) 40 (1992) pp 107-126.

4. Afrati, F., Papadimitriou, C.H., Papageorgiou, G., Roussou, A., Sagiv, Y., Ullman, J.D., "On the Convergence of Query Evaluation", Journal of Computer and Systems Sciences, Vol. 38 No 2, April 1989 (special issue), pp. 341-359.

3. Afrati, F., Papadimitriou, C.H., Papageorgiou, G. "The Synthesis of Communication Protocols", Algorithmica Vol 3, 1988 (special issue on distributed computing), pp. 451-472.

2. Afrati, F., Cosmadakis, S., Papadimitriou, C.H., Papageorgiou, G., Papakonsta ntinou "The Complexity of the Travelling Repairman Problem", RAIROTheoretical Informatics and Applications, Vol.20, No.1, 1986, pp.79-87.

1. Afrati, F., Papadimitriou, C.H., Papageorgiou, G., "The Complexity of Cubical Graphs" Information and Control Vol.66, No.1-2, July-August 1985 pp. 53-60.

Papers in Conference Proceedings

50. Foto N. Afrati, Chen Li, Prasenjit Mitra: On Containment of Conjunctive Queries with Arithmetic Comparisons. EDBT 2004: 459-476, 2004

49. Foto N. Afrati, Aristides Gionis, Heikki Mannila: Approximating a collection of frequent sets. KDD 2004: 12-19

48. Foto N. Afrati, Theodore Andronikos, Vassia Pavlaki, E. Foustoukos, Irène Guessarian: From CTL to Datalog. PCK50 2003: 72-85

47. Foto N. Afrati, Chen Li, Prasenjit Mitra: Answering Queries Using Views with Arithmetic Comparisons (ps format). PODS 2002: 209-220

46. F. Afrati, Τ. Aslanidis, E. Bampis and I. Milis, Scheduling in switching networks with set-up delays, In Proc. 4èmes Rencontres Francophones sur les aspects Algorithmiques des Télécommunications (ALGOTEL'2002).

45. Agis Papantoniou, Ezz Hattab, Foto N. Afrati, Eleftherios Kayafas, Vassilis Loumos: Change Management, a Critical Success Factor for e-Government. DEXA Workshop 2001: 402-406

44. F. Afrati and I. Milis, Designing PTASs for MIN-SUM scheduling problems (ps format), In Proc. 13th International Symposium Fundamentals of Computation Theory (FCT'01), Invited paper in the Workshop on Efficient Algorithms (WEA'01), Lecture Notes in Computer Science (Springer Verlag) LNCS-2138 (2001) 432-444.

43. Foto N. Afrati, Chen Li, Jeffrey D. Ullman: Generating Efficient Plans for Queries Using Views (ps format). SIGMOD Conference 2001

42. F. Afrati, E. Bampis, L. Finta and I. Milis, Scheduling trees with large communication delays on two identical processors, In Proc. 6th International Euro-Par Conference (EURO-PAR'00), Lecture Notes in Computer Science (Springer Verlag) LNCS-1900 (2000) 288-295.

41. Foto N. Afrati, Evripidis Bampis, Aleksei V. Fishkin, Klaus Jansen, Claire Kenyon: Scheduling to Minimize the Average Completion Time of Dedicated Tasks (ps format). FSTTCS 2000: 454-464

40. Foto N. Afrati, Hans Leiß, Michel de Rougemont: Definability and Compression (ps format). LICS 2000: 63-73

39 . F. Afrati, E. Bampis, C. Kenyon and I. Milis, Scheduling on a constant number of processors, In Proc. 2nd International Workshop on Approximation Algorithms for Combinatorial Optimization Problems (APPROX’99), Lecture Notes in Computer Science (Springer Verlag) LNCS-1671 (1999) 281-287.

38. F. Afrati, E. Bampis, C. Chekuri, D. Karger, C. Kenyon, S. Khanna, I. Milis, M. Queyranne, M. Skutella, C. Stein and M. Sviridenko, Approximation schemes for minimizing average weighted completion time with release dates (ps format), Ιn Proc. 40th IEEE Symposium on Foundations of Computer Science (FOCS’99) (1999) 32-43.

37. Foto N. Afrati, Manolis Gergatsoulis, Theodoros G. Kavalieros: Answering Queries Using Materialized Views with Disjunctions (ps format). ICDT 1999: 435-452

36. Foto N. Afrati, Eugenie Foustoucos, Theodore Andronikos: Datalog Trees and Their Automata (.PS Format). In proceedings of the 2nd Pan Hellenic Symposium on Logic, Delphi 1999

35 . Foto N. Afrati, I. Karali, Theodoros Mitakos: On Inheritance in Object Oriented Datalog. IADT 1998: 280-289

34. Foto N. Afrati, Theodore Andronikos, Theodore G. Kavalieros: On the Expressiveness of Query Languages with Linear Constraints; Capturing Desirable Spatial Properties (ps format). CDB 1997: 105-115

33. Foto N. Afrati, Francesca Toni: On the Relationsship Between Chain Queries and Linear Datalog Programs (ps format). DDLP 1997

32. Foto N. Afrati, Irène Guessarian, Michel de Rougemont: The Expressiveness of Datalog Circuits (DAC) (ps format). MFCS 1997: 119-128

31. Foto N. Afrati, Phokion G. Kolaitis: Database Theory - ICDT '97, 6th International Conference, Delphi, Greece, January 8-10, 1997, Proceedings Springer 1997

30. Foto N. Afrati: Arity Hierarchies for Fixed-Point Logics (.PS Format)
Panhellenic Symposium on Logic, Cyprus, 1997

29. Foto N. Afrati, Isambo Karali, Theodoros Mitakos: Datalog, Units and Information Hiding (.PS Format)
Languages and Models with Objects '97, Roscoff France.

28 . Foto N. Afrati, Manolis Gergatsoulis, Maria Katzouraki: On Transformations into Linear Database Logic Programs (ps format). Ershov Memorial Conference 1996: 433-444

27. Afrati, F., Kavalieros, Th., Theodoratos, D., "On the Complexity of Updating Knowledge Bases", Proceedings of Conference of Greek CS Society, Athens, Dec. 1995.

26. Afrati,F., Andronikos,Th., Kavalieros,Th., "On the Expressiveness of Query Languages with Linear Constraints: Considerations on Spatial Data" Proceedings of 2nd workshop on Constraint Databases, Springer Verlag Lecture Notes in CS, 1995.

25. Afrati,F., Cosmadakis,S., Grumbach,S., Kuper,G., "Linear vs. Polynomial Constraints in Database Query Languages", 2nd Workshop on Principles and Practice of Constraint Programming, 1994.

24. Afrati,F., "Bounded Arity Datalog (<>) Queries on Graphs", Proceeding s of the 13th ACM PODS, Symposium on the Principles of Database Systems, 1994.

23. Afrati, F, Kavalieros T., Theodoratos D., "Revising Propositional Horn Clause Knowledge Bases" (.PS Format), ERCIM-11/94-R034, November '94

22. Afrati,F., Cosmadakis,S.,Yannakakis,M., "Datalog vs. Polynomial Time", Proceedings of the 10th ACM PODS, Symposium on the Principles of Database Systems, 1991, pp.13-25; (the final version appears above as a refereed journal entry).

21. Afrati,F., "Finding Strongly Connected Components in Series Parallel Graphs". Proceedings TENCON'91, New Dehli, India,1991.

20. Afrati,F., Coutras,C., "A Hypertext Model Supporting Query Mechanisms&qu ot;, Proceedings of the European Conference on Hypertext 1990, published in volume Hypertext: Concepts, systems and applications by Cambridge University Press.

19. Afrati,F., Cosmadakis,S., "Expressiveness of Restricted Recursive Queries", Proceedings of the 21st ACM STOC, Symposium on Theory of Computing, May 1989, pp. 113-126.

18. Afrati,F., Stafylopatis,A., "Performance Considerations on a Random Graph Model for Parallel Processing". Proceedings of IMACS Conference, Paris 1988.

17. Afrati,F, Papadimitriou,C.H., Papageorgiou,G., "Scheduling Dags to Minimize Time and Communication", Proceedings of the Aegian Workshop on Computing (AWOC), June 1988.

16. Afrati,F., Papadimitriou,C.H., "The Parallel Complexity of Simple Chain Queries", Proceedings of the 6th ACM PODS, Symposium on the Principles of Database Systems, March 1987 pp. 210-213; (the final version appears above as a refereed journal entry).

15. Afrati,F., Papadimitriou,C.H., Papageorgiou,G., Roussou,A., Sagiv,Y.,Ullman,J .D., "Convergence of Sideways Query Evaluation", Proceedings of the 5th ACM PODS, Symposium on the Principles of Database Systems,March 1986 pp. 24-30; (the final version appears above as a refereed journal entry).

14. Afrati,F., Papadimitriou,C.H., Papageorgiou,G. "The Synthesis of Communication Protocols", Proceedings of the 5th ACM PODC. Symposium on the Principles of Distributed Computing, August 1986;(the final version (appears above as a refereed journal entry).

13. Afrati,F., Anagnostou,M., Protonotarios,E.N., "Performance Evaluation of Hybrid ARQ Protocols", Proceedings of IEEE Symposium on Information Theory, June 1985.

12. Afrati,F., Dendrinos,M., "Symmetry and Cyclicity Properties of some Low Complexity Codes", Proceedings of IEEE Symposium on Information Theory, June 1985.

11. Anagnostou,M., Afrati,F., "On the Complexity and Accuracy of Algorithms used for the Performance Evaluation of ARQ Protocols", Proceedings of the IEEE International Conference MELECON, 1985.

10. Afrati,F., Papaspirou,V., "Optimal Extension of a Linear Code", Proceedings of the IEEE International Conference MELECON, 1985.

9. Afrati,F., Papadimitriou,C.H., Papageorgiou,G., "The Complexity of Cubical Graphs", Proceedings of the 11th ICALP, International Colloquium on Automata, Languages and Programming, Lecture Notes in Computer Science appears above as a refereed journal entry),1984.

8. Afrati,F., Dendrinos.M., "Considerations on Low Complexity Codes Concerning Symmetry and Cyclicity", Proceedings DIGITECH, 1984.

7. Afrati,F., Ballas,D., "Analysis of Error Correcting Codes for the Binary Symmetric Channel", Proceedings MECO 1983.

6. Afrati,F., Anagnostou,M., Mikroudis,N., "A Hybrid ARQ Scheme using Convolutional Codes", Proceedings MECO 1983.

5. Afrati,F., Anagnostou,M., Mikroudis,N.,"A Hybrid Scheme for the Improvement of the ARQ Protocols", Proceedings of the IEEE International Conference MELECON, 1983.

4. Afrati,F., "A Random Search Algorithm for the Construction of Ternary Linear Block Codes", Proceedings of the IEEE International Conference MELECON, 1983.

3. Afrati,F., "A Graph-Theoretic Approach to the Binary Linear Block Code Construction", Proceedings of the IEEE International Symposium on Information Theory, 1982.

2. Afrati,F., " A Branch-and-Bound Method for the Construction of Binary Linear Block Codes", Proceedings of the IEEE International Conference MELECON, 1981.

1. Afrati,F., Constantinides,A.G., " The Use of Graph Theory in Binary Block Code Construction", Proceedings of the IEEE International Conference on Digital Signal Processing, 1978.

Undergraduate Cources

Discrete Mathematics in Computer Science

We use the Gradiance Online Accelerated Learning

Sets. Finite and infinite sets. Countable sets. The diagonalizatiom method. The inclusion-exclusion principle. Mathematical induction. Combinations and permutations. Introduction to format languages and finite automata. Grammars. Groups, rings and fields. Isomorphisms, automorphisms and homeomorphisms. Permutation groups. Relations. The job scheduling problem. Binary relations, lattices, partially ordered sets. Equivalence relations and partitions. Introduction to Boolean algebra.

Theory of Computation

Computational models for sequential algorithms. Turing machine. Random access machine (RAM). The class of polynomial problems. Algorithms on graphs. Shortest path. Minimum spanning tree. Biconnectivity-Strongly connected components. Maximum flow. The class of non-deterministically polynomial (NP) problems. Polynomial reductions. NP-complete problems. Parallel algorithms. Computational models for parallel algorithms. Interconnection networks. The parallel random access machine (PRAM). The class NC. log-space reductions. P-compete problems. Efficient and optimal parallel algorithms.

Information Theory

The uncertainly function as a measure of information. Properties of the uncertainty function. Source coding-Huffman codes. Optimum codes. Shannon's first theorem. Channel capacity. Shannon,s second theorem. Error correcting codes. Lower and upper bounds. The sphere-packing bound. Hamming codes. Linear codes. Cyclic codes, BCH codes. Error correcting capability of BCH codes. Shift registers for encoding and decoding cyclic codes. Continous channel with Gaussian noise. Average error probability.

Graduate Cources

Data Mining Algorithms

What is Data Mining, Applications, The Data-Mining Communities, Association-Rule Mining : Association Rules and Frequent Itemsets , MarketBasket Mining, The APriori Algorithm, PCY Algorithm, Low-Support/High Correlation : Min Hashing Algorithm, LSH Algorithm, kMin Hashing Algorithm, Hamming LSH Algorithm, Query Flocks: Query Flock Notation, Execution Strategies, Optimal Query Flock, Searching the Web : Page Rank, Problems With Real Web Graphs, Hubs and Authorities, Google Solution to Dead Ends and Spider Traps, Google AntiSpam Devices, Web Mining :The DICE Engine, Books and Authors, What is Pattern, Finding Data Occurrences Given Data,, Finding Data Occurrences Given Patterns, Clustering : Distance Measure, The Curse of Dimensionality, Approaches to Clustering, The k-Means Algorithm, The BFR Algorithm Fastmap in Clustering Algorithms, Hierarchical Clustering, The GRGPF Algorithm, CURE Algorithm, Matching Sequences : Fourier Transforms as Indexes for Sequences, Matching Queries to Sequences of the Same Length, Queries That are Shorter than the Sequences, Trails, Matching Queries of Arbitrary Length, Mining Event Sequences : Episode Mining, Monotonicity of Episodes and the APriori Algorithm, Checking Parallel Episodes, Checking Serial Episodes, Counting Composite Events.

Database Theory

Introduction to SQL. Relational Algebra. Introduction to Datalog, Stratified Negation, Stable and Well-Founded Models. Conjunctive queries with Negation and Arithmetic. Query Containment. Answering Queries using Views; the Bucket algorithm, the inverse rule algorithm. Data Dependencies, Normalization. Acyclic Hypergraphs, Computing Acyclic Joins. The Universal Relation. Introduction to Magic sets, Rule-goal trees, the magic-sets algorithm.

Online Homeworks: Gradiance