The reasonable man adapts himself
to the world; the unreasonable one persists in trying to adapt the world to
himself. Therefore, all progress depends on the unreasonable man.

George
Bernard Shaw

- Introduction to ACCS
- Personal Details
- Education
- Scholarships
- Professional Experience
- Courses Taught
- Topics for Student
Projects and Theses
- Languages
- Selected Publications
- Some Photos
- Favorite Links
- Special Projects
- "Dijital Deliller" duyurusu - 2013
- "30 Mart Seçimleri"
- Yeni "Dijital Deliller" duyurusu – 6.5.2014

I am a professor of computer science in Boğaziçi University. My research interests are Theoretical Computer Science and Artificial Intelligence.

In "civilian" life, I am known as an overall nice guy with a liking for science fiction, Western languages, and all kinds of funny things.

**Full Name:**

Ahmet Celal Cem Say

**Date and Place of Birth:**

**Nationality:**

Turkish

**Address:**

Boğaziçi University, Department of Computer Engineering, Bebek, 34342, İstanbul, Turkey.

**Phone:**

+90-212-3596628

**Fax:**

+90-212-2872461

**Email:**

say at boun dot edu dot tr

**Erdşs Number:**

at most 3

- T.E.D. Ankara High School (1983)
- B.S. in
*Computer Engineering*from Boğaziçi University (1987) - Ph.D. in
*Computer Engineering*from Boğaziçi University (1992) - Turkish Army School of
*Communications, Electronics and Information Systems*(1995)

- High school scholarship of TüBİTAK (Turkish Scientific & Technological Research Institution)
- Ph.D. scholarship of TüBİTAK
- University of Vienna Language School Scholarship
- Italian Institute of Culture Language School Scholarship

- 1987-1992 Boğaziçi University, Department of Computer Engineering, Research Assistant.
- 1995-1996 Turkish Naval Inventory Control Center Command, Supply Services Software Officer.
- 1992-1996 Boğaziçi University, Department of Computer Engineering, Assistant Professor.
- 1996-2003 Boğaziçi University, Department of Computer Engineering, Associate Professor.
- 2003-... Boğaziçi University, Department of Computer Engineering, Professor.

(I have been seen in Işık, Galatasaray, and Bilgi Universities as well.)

- Introductory Computing & Programming,
- Java,
- Discrete Computational Structures,
- Formal Languages and Automata Theory,
- Introduction to Artificial Intelligence,
- Natural Language Processing,
- Theory of Computation,
- Probabilistic and Quantum Finite Automata,
- Advanced Topics in Theoretical Computer Science,
- Quantum Algorithms,
- Qualitative Reasoning,
- Complexity Theory.

- A. C. Cem Say, Selahattin
Kuru, "Improved
filtering for the QSIM algorithm,"
*IEEE Transactions on Pattern Analysis and Machine Intelligence*Vol. 15, pp. 967-971, 1993. - A. C. Cem Say, Selahattin
Kuru, "Qualitative
system identification: Deriving structure from behavior,"
*Artificial Intelligence*Vol. 83, pp. 75-141, 1996. - A. C. Cem Say, Selahattin
Kuru, "Postdiction using reverse qualitative simulation,"
*IEEE Transactions on Systems. Man, and Cybernetics**Part A: Systems and Humans*Vol. 27, pp. 84-95, 1997. - A. C. Cem Say, "L'Hôpital's
filter for QSIM,"
*IEEE Transactions on Pattern Analysis and Machine Intelligence*Vol. 20, pp. 1-8, 1998. - A. C. Cem Say, "Making use of
contradictory behavior information in qualitative reasoning,"
*IEEE Transactions on Pattern Analysis and Machine Intelligence*Vol. 21, pp. 781-786, 1999. - A. C. Cem Say, "Understanding arithmetic
problems in Turkish,"
*International Journal of Pattern Recognition and Artificial Intelligence*Vol. 15, pp. 359-374, 2001. - A. C. Cem Say,
"Improved reasoning about infinity using qualitative
simulation,"
*Computing and Informatics*Vol. 20, pp. 487-507, 2001. - A. C. Cem Say, "Problems in
representing liquid tanks with monotonicity constraints: A case study in
model-imposed limitations on the coverage of qualitative simulators,"
*Artificial Intelligence Review*Vol. 17, pp. 291-317, 2002. - A. C. Cem Say,
"Sound and complete qualitative simulation requires "quantitative"
filtering,"
*Annals of Mathematics and Artificial Intelligence*Vol. 38, pp. 257-267, 2003. - Tolga Kşnik,
A. C. Cem Say, "Duration consistency filtering
for qualitative simulation,"
*Annals of Mathematics and Artificial Intelligence*Vol. 38, pp. 269-309, 2003. - A. C. Cem Say, H. Levent
Akın, "Sound and complete
qualitative simulation is impossible,"
*Artificial Intelligence*Vol. 149, pp. 251-266, 2003. - A. C. Cem Say, A. Kutsi
Nircan, "Random
generation of monotonic functions for Monte Carlo solution of qualitative
differential equations,"
*Automatica*Vol. 41, pp. 739-754, 2005. - şzgür Yılmaz, A. C. Cem Say, "Causes of ineradicable
spurious predictions in qualitative simulation,"
*Journal of Artificial Intelligence Research*, Vol. 27, pp. 551-575, 2006. - Abuzer
Yakaryılmaz, A. C. Cem Say, "Efficient probability amplification in
two-way quantum finite automata,"
*Theoretical Computer Science*, Vol. 410, pp. 1932-1941, 2009. (doi:10.1016/j.tcs.2009.01.029) - Rūsiņš Freivalds,
Abuzer Yakaryılmaz, A. C. Cem Say, "A new family of nonstochastic
languages,"
*Information Processing Letters*, Vol. 110, pp. 410-413, 2010. doi: 10.1016/j.ipl.2010.03.011 - Abuzer Yakaryılmaz, A. C.
Cem Say, "Languages recognized by nondeterministic quantum finite
automata,"
*Quantum**Information and Computation*, Vol. 10, pp. 747-770, 2010. - Abuzer Yakaryılmaz, A. C. Cem Say, "Succinctness
of two-way probabilistic and quantum finite automata,"
*Discrete Mathematics and Theoretical Computer Science*, Vol. 12, pp.19-40, 2010. - Abuzer Yakaryılmaz, A. C. Cem Say, "Unbounded-error
quantum computation with small space bounds,"
*Information and Computation*, Vol. 209, pp.873-892, 2011. [slightly older version at arXiv:1007.3624] - Abuzer Yakaryılmaz, Rūsiņš Freivalds, A. C.
Cem Say, Ruben Agadzanyan, "Quantum computation with write-only memory,"
*Natu**ral Computing*, Vol. 11, pp.81-94, 2012. doi: 10.1007/s11047-011-9270-0 - A. C. Cem
Say, Abuzer Yakaryılmaz, "Computation with multiple CTCs of fixed length
and width,"
*Natural Computing*, Vol. 11, No. 4, pp. 579-594, 2012. doi: 10.1007/s11047-012-9337-6 (errata) - A. C. Cem
Say, Abuzer Yakaryılmaz, "Quantum counter automata,"
*International Journal of Foundations of Computer Science*, Vol. 23, No. 5, pp. 1099-1116, 2012. doi: 10.1142/S012905411250013X - Abuzer
Yakaryılmaz, A. C. Cem Say, "Proving the power of postselection,"
*Fundamenta**Informaticae*, Vol. 123, No. 1, pp. 107-134, 2013. - Abuzer
Yakaryılmaz, A. C. Cem Say, "Tight bounds for the space complexity of
nonregular language recognition by real-time machines,"
*International Journal of Foundations of Computer Science*, Vol. 24, No. 8, pp. 1243-1253, 2013. DOI. - A. C. Cem Say, Abuzer
Yakaryılmaz, "Finite state
verifiers with constant randomness,"
*Logical Methods in Computer Science*, Vol. 10(3:6)2014, pp. 1–17. (errata) - Uğur
Küçük, A. C. Cem Say, Abuzer Yakaryılmaz, "Finite automata with advice tapes,"
*International Journal of Foundations of Computer Science*, Vol. 25, No. 8, pp. 987-1000, 2014. - H. Gşkalp Demirci, A. C.
Cem Say, Abuzer Yakaryılmaz, "The complexity of debate checking,"
*Theory of Computing Systems*, Vol. 57, pp. 36-80. DOI 10.1007/s00224-014-9547-7, 2015. - Abuzer Yakaryılmaz, A. C.
Cem Say, H. Gşkalp Demirci, "Debates with small transparent quantum
verifiers,"
*International Journal of Foundations of Computer Science*, Vol. 27, No. 2, pp. 283-300, 2016.

- A. C. Cem Say, Selahattin
Kuru, "Nitel model tanılama," (in Turkish) Bilkon-91 1991
*Bilkent Elektrik-Elektronik ve Bilgisayar Mühendisliği Konferansı*, Ankara, 1991, pp. 363-366. - A. C. Cem Say, Selahattin
Kuru, "Qualitative system identification,"
*Lecture Notes in Control and Information Sciences*Vol. 180, (*System Modeling and Optimization: Proceedings of the 15th IFIP Conference, Zürich, Switzerland, September 2-6, 1991*),1992, pp. 657-666. - A. C. Cem Say, Selahattin
Kuru, "An extension of the corresponding value technique in
qualitative modeling and simulation,"
*Birinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu*, Ankara, 1992, pp.23-28. - A. C. Cem Say, Selahattin
Kuru, "QSI: Constructing models for qualitative simulation,"
*Advances in Simulation '92 Symposium*, Boğaziçi Univ., İstanbul, 1992, pp. 37-46. - A. C. Cem Say, Selahattin
Kuru, "Automatic construction of qualitative models," in
*Intelligent Systems: Safety, Reliability, and Maintainability Issues*, Springer-Verlag, Berlin, 1993, pp. 177-193. - Cem Say, Sidal Sen, Ruhver
Barengi, "'Bir Kelime - Bir İşlem' oynayan program," (in
Turkish)
*İkinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu*, İstanbul, 1993, pp. 349-355. - İlan Berker, A. C. Cem Say,
"A crossword puzzle generator for Turkish,"
*Proceedings of the Eighth International Symposium on Computer and Information Sciences (ISCIS-VIII)*, İstanbul, 1993, pp. 474-477. - çiğdem Aytekin, A. C. Cem
Say, Erkut Akçok, "ELIZA speaks
Turkish: A conversation program for an agglutinative language,"
*üçüncü Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu*, Ankara, 1994, p. 435. - A. C. Cem Say, "Türkçe
'anlayan' programlar," (in Turkish)
*TBD Bilişim '94*, İstanbul, 1994, pp. 191-195. - Metin şrsel, A. C. Cem Say,
"Representing descriptions of flags,"
*Proceedings of the Ninth International Symposium on Computer and Information Sciences (ISCIS-IX)*, Antalya, 1994, pp. 575-582. - Müjdat Pakkan, A. C. Cem
Say, "Qualitative collision detection in the roller coaster
world,"
*Proceedings of the Ninth International Symposium on Computer and Information Sciences (ISCIS-IX)*, Antalya, 1994, pp. 583-590. - Murat Işık, A. C. Cem Say,
"Qualitative noise filtering and the implementation of QF as a
preprocessor to QSI,"
*Proceedings of the Tenth International Symposium on Computer and Information Sciences (ISCIS-X)*, Aydın, 1995, pp. 145-152. - A. C. Cem Say, "Functions
representable in pure QSIM,"
*Beşinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu*, İstanbul, 1996, pp. 251-255. - A. C. Cem Say, "Qualitative
timeline analysis," in
*New Trends in Artificial Intelligence and Neural Networks*. EMO Scientific Books, Ankara, 1997, pp. 121-126. - F. Canan Pembe, A. C. Cem
Say, "A linguistically motivated information retrieval system for
Turkish,"
*Lecture Notes in Computer Science*Vol. 3280, (*Proceedings of the Nineteenth International Symposium on Computer and Information Sciences*), 2004, pp. 741-750. - Uğur Küçük, A. C. Cem Say, "Improved simulation of
quantum random walks,"
*Lecture Notes in Computer Science*Vol. 3733, (*Proceedings of the Twentieth International Symposium on Computer and Information Sciences*), 2005, pp. 937-946. - Abuzer Yakaryılmaz,
Rūsiņš Freivalds, A. C. Cem Say, Ruben Agadzanyan, "Quantum
computation with devices whose contents are never read,"
*Lecture Notes in Computer Science*Vol. 6079, (*Proceedings of the 9th International Conference on Unconventional Computation)*, 2010, pp. 164-174. [doi:10.1007/978-3-642-13523-1_18] - Nuri Taşdemir, A. C. Cem Say, "Models of pushdown automata
with reset,"
*Lecture Notes in Computer Science*Vol. 6795, (*Proceedings of the 15th International Conference on Developments in Language Theory*), 2011, pp. 417-428. - A. C. Cem Say, Abuzer Yakaryılmaz, "Finite state verifiers
with constant randomness,"
*Lecture Notes in Computer Science*Vol. 7318,*How the World Computes: Turing Centenary Conference and 8th Conference on Computability in Europe*,*CiE 2012*, Cambridge, UK, June 18-23, 2012,*Proceedings*, 2012, pp.646-654. - Uğur Küçük, A. C. Cem Say, Abuzer Yakaryılmaz, "Finite automata with advice tapes," LNCS Vol. 7907, (Proceedings of the 17th International Conference on Developments in Language Theory) pp. 301-312, 2013.
- şzlem Salehi, Abuzer Yakaryılmaz, A. C. Cem Say, "Real-time vector automata," LNCS Vol. 8070, (Proceedings of the 19th International Symposium on Fundamentals of Computation Theory) pp. 293-304, 2013.
- Abuzer Yakaryılmaz, A. C. Cem Say, Gşkalp Demirci, "Debates with small transparent quantum verifiers," LNCS Vol. 8633, (Proceedings of the 18th International Conference on Developments in Language Theory) pp. 327-338, 2014.
- Ryan O’Donnell, A. C. Cem Say, "One time-traveling bit is as good as logarithmically many," LIPIcs Vol. 29 (Proceedings of the 34th International Conference on Foundation of Software Technology and Theoretical Computer Science) pp. 469-480, 2014.
- Cafer Caferov, Barış Kaya, Ryan O’Donnell, A. C. Cem Say, "Optimal bounds for estimating entropy with PMF queries," LNCS Vol. 9235, (Proceedings of the 40th International Symposium on Mathematical Foundations of Computer Science) pp. 187-198, 2015.

- Reha
Kamil Gerçeker, A. C. Cem Say, "Using polynomial approximations to
discover qualitative models," Proceedings of the
*20*Editors: Chris Bailey-Kellogg and Benjamin Kuipers, pp. 71-80, Darthmouth College, Hanover, New Hampshire, USA, 2006.^{th}International Workshop on Qualitative Reasoning. - Nuri Taşdemir, A. C. Cem Say, "Provably
spurious qualitative simulation predictions that just won’t go away," Proceedings
of the
*21*Editor: Chris Price, pp. 170-180, Aberystwyth, UK, 2007.^{st}International Workshop on Qualitative Reasoning. - Abuzer
Yakaryılmaz, A. C. Cem Say, "Language
recognition by generalized quantum finite automata with unbounded error,"
*4*, TQC2009, Waterloo, Ontario, Canada, 2009. (arXiv:0901.2703).^{th}Workshop on Theory of Quantum Computation, Communication, and Cryptography - Abuzer
Yakaryılmaz, A. C. Cem Say, "NP has log-space verifiers with fixed-size public
quantum registers," (
*8th Central European Quantum Information Processing Workshop*), 2011. [arXiv:1101.5227] - Gşkalp Demirci, A. C. Cem Say, Abuzer Yakaryılmaz, "The
complexity of debate checking," http://eccc.hpi-web.de/report/2014/016
- Abuzer Yakaryılmaz, A. C. Cem Say, Gşkalp Demirci,
"Debates with small transparent quantum verifiers," arXiv: 1405.1655
- Gşkalp Demirci, Mika
Hirvensalo, Klaus
Reinhardt, A. C. Cem Say, Abuzer Yakaryılmaz, "Classical and quantum realtime alternating automata,"
6th International Workshop on Non-Classical Models of Automata and
Applications, 2014. (arXiv: 1407.0334)
- Ryan
O’Donnell, A. C. Cem Say, "One time-traveling bit is as good as
logarithmically many," http://eccc.hpi-web.de/report/2014/091
- A. C. Cem Say, Abuzer Yakaryılmaz, "Magic coins
are useful for small-space quantum machines," http://eccc.hpi-web.de/report/2014/159/
- Ryan
O’Donnell, A. C. Cem Say, "The weakness of CTC qubits and the power of
approximate counting," 2015.
- şzlem Salehi, A. C. Cem Say, "Homing vector automata," 7th International Workshop on Non-Classical Models of Automata and Applications, 2015. (arXiv:1504.04859)
- Uğur Küçük, A. C. Cem Say, Abuzer Yakaryılmaz,
"Inkdots as advice to small-space machines," arXiv:1509.03712.

- M. Ufuk çağlayan, Fedon Kadifeli, A. C. Cem Say.
*Standard C Programming*. Boğaziçi University Publications, 1989. - Fedon Kadifeli, A. C. Cem Say, M. Ufuk
çağlayan.
*Standart C Programlama Dili*(in Turkish). Sarmal Yayınları, 1993. (Translated and updated from (1) by F. Kadifeli.)

- Selahattin Kuru, H. Levent Akın, A. C. Cem
Say, Ethem Alpaydın
(Eds.).
*İkinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu Bildiriler*. Boğaziçi üniversitesi, İstanbul, 1993. - A. C. Cem Say, Günhan Dündar (Eds.)
*Proceedings of the Eighth Turkish Symposium on Artificial Intelligence and Neural Networks.*Boğaziçi üniversitesi, İstanbul, 1999.

- A. C. Cem Say, "Sen de mi şair oldun ey
bilgisayar?"
*çağrı Dergisi*, no. 400, 1993, p. 9. - A. C. Cem Say, "Sıcak bir TAINN
günü"
*Beşinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu*, İstanbul, 1996, p. 381. - Cem Say, "Akla doğru"
*Cogito*, no. 13, 1998, pp. 67-74. - Cem Say, "Gşdel’in eksiklik teoremi"
*Matematik Dünyası*, Yıl 14, Sayı 4, 2005, 67-71. - Cem Say, "Nitel benzetim"
*Türkiye Bilişim Ansiklopedisi*. TBV-Papatya Yayıncılık Eğitim, 611-615, 2006. - Cem Say, "Yapay zekâ, doğal zekâ ve şzgürlük"
*Bilim ve ütopya*, Yıl 18, Sayı 220, 2012, 42-48. - A. C. Cem Say, "Diller, çşzümsüz problemler ve
sonsuzluk"
*Bilgisayar ve Beyin: "Bilgi İşleyen Makine Olarak Beyin" Toplantıları*, yayına hazırlayan: Haluk Bingşl, Pan Yayıncılık, 177-184, 2012. - Cem Say, "Yapay zekâ ve Gşdel teoremi"
*Bilgisayar ve Beyin: "Bilgi İşleyen Makine Olarak Beyin" Toplantıları*, yayına hazırlayan: Haluk Bingşl, Pan Yayıncılık, 254-264, 2012. - A.
C. Cem Say, Abuzer Yakaryılmaz, "Quantum finite
automata: A modern introduction,"
*Computing with New Resources,*LNCS Vol. 8808, (Essays Dedicated to Josef Gruska on the Occasion of His 80th Birthday) pp. 208-222, 2014. arXiv: 1406:4048

**Doctoral Dissertation**:
Qualitative
System Identification. Boğaziçi University, 1992.