Summary

Research Interests

A secondary research theme is the practical application of well-established research to down-to-earth problems, e.g. natural language processing for web applications.

I have primarily worked in the following areas:

• Rewriting and Lambda Calculus
• Computability Theory and Complexity Theory
• Constructive/Computable/Recursive Mathematics
• Dynamical Systems

• Computation by biological and other physically or chemically constrained devices, for example biocomputers
• Natural language processing
• Human-computer interaction

Publications

International peer-reviewed journals:

• [AJ16] J.S.B. Nielsen, J.G. Simonsen, "Experimental Investigation of the Equidistribution of Irrational Algebraic Numbers".
  Mathematics of Computation. Accepted for publication.

• [AJ15] N.D. Jones, J.G. Simonsen, "Programs = Data = First-Class Citizens in a Computational World".
  Philosophical Transactions of the Royal Society A. Accepted for publication.

• [J14] L. Hartmann, N.D. Jones, J.G. Simonsen, S. Vrist, "Programming in Biomolecular Computation: Programs, Self-Interpretation and Visualisation".
  Scientific Annals of Computer Science XXI(1), p. 73--106
  published version (open access)

• [J13] J. Ketema, J.G. Simonsen, "Infinitary Combinatory Reduction Systems".
  Information and Computation 209(6), p. 893--926, 2011.
  published version

• [J12] J.G. Simonsen, "Beta-Shifts, their Languages and Computability".
  Theory of Computing Systems 48, p. 297--318, 2011.
  published version preliminary version

• [J11] J. Endrullis, H. Geuvers, J.G. Simonsen, H. Zantema, "Levels of Undecidability in Rewriting".
  Information and Computation 209(2), p. 227--245, 2011.
  published version preliminary version

• [J10] J. Ketema, J.G. Simonsen, "Infinitary Combinatory Reduction Systems: Normalising Reduction Strategies".
  Logical Methods in Computer Science 6(1), paper 7, 2010.
  published version (open access)

• [J9] J. Ketema, J.G. Simonsen, "Infinitary Combinatory Reduction Systems: Confluence".
  Logical Methods in Computer Science 5(4), paper 3, 2009.
  published version (open access)

• [J8] J.G. Simonsen, "On the Computational Complexity of the Languages of General Symbolic Dynamical Systems and Beta-Shifts".
  Theoretical Computer Science 410, p. 4878--4891, 2009.
  published version preliminary version

• [J7] F. Henglein, K.F. Larsen, J.G. Simonsen, C. Stefansen, "POETS: Process-Oriented Event-Driven Transaction Systems".
  Journal of Logic and Algebraic Programming 78(5), p. 381--401, 2009.
  published version preliminary version

• [J6] J. Andersen, E. Elsborg, F. Henglein, J.G. Simonsen, C. Stefansen, "Compositional Specification of Commercial Contracts".
  International Journal on Software Tools for Technology Transfer 8(6), p.485--516, 2006.
  published version preliminary version

• [J5] J.G. Simonsen "On Local Non-Compactness in Recursive Mathematics"
  Mathematical Logic Quarterly 52(4), p. 323--330, 2006.
  published version preliminary version

• [J4] J.G. Simonsen, "On Modularity in Infinitary Rewriting".
  Information and Computation 204(6), p. 957--988, 2006.
  published version preliminary version

• [J3] J.G. Simonsen "On the Computability of the Topological Entropy of Subshifts"
  Discrete Mathematics and Theoretical Computer Science 8, p. 83--96, 2006.
  published version (open access).

• [J2] J.G. Simonsen, "Specker Sequences Revisited".
  Mathematical Logic Quarterly (formerly Zeitschrift fuer Mathematische Logik und Grundlagen der Mathematik). 51(5), p. 532--540, Wiley Interscience, 2005.
  preliminary version

• [J1] J.G Simonsen, "On Confluence and Residuals in Cauchy Convergent Transfinite Rewriting"
  Information Processing Letters 91(4), p.141-146, Elsevier, 2004.
  published version preliminary version

International peer-reviewed conferences

• [C14] E.P. Bugge, K.L. Juncher, B.S. Mathiesen, J.G: Simonsen, "Using Sequence Alignment and Voting to Improve Optical Music Recognition from Multiple Recognizers".
  Proceedings of the 12th International Society for Music Information Retrieval Conference (ISMIR '11).
  published version (open access)

• [C13] A. Schnabl, J.G. Simonsen, "The Exact Hardness of Deciding Derivational and Runtime Complexity".
  Proceedings of the 20th Conference on Computer Science Logic (CSL '11). LIPIcs 12, p. 481-495
  published version (open access)

• [C12] S. Hedegaard, J.G. Simonsen, "Lost in Translation: Authorship Attribution using Frame Semantics".
  Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies (ACL '11) (Short paper), p.65-70
  published version (open access)

• [C11] N.B.B. Grathwohl, J. Ketema, J.D. Pallesen, J.G. Simonsen, "Anagopos: A Reduction Graph Visualizer for Term Rewriting and Lambda Calculus".
  Proceedings of the 22nd International Conference on Rewriting Techniques and Applications (RTA '11). LIPIcs 10, p. 61-70.
  published version (open access) code

• [C10] C. Appel, V. van Oostrom, J.G. Simonsen, "Higher-Order (Non-)Modularity".
  Proceedings of the 21st International Conference on Rewriting Techniques and Applications (RTA '10). LIPIcs 7, p. 17-32. Schloss Dagstuhl, 2010.
  published version (open access)

• [C9] J.G. Simonsen, "Weak Convergence and Uniform Normalization in Infinitary Rewriting".
  Proceedings of the 21st International Conference on Rewriting Techniques and Applications (RTA '10). LIPIcs 7, p. 311-324. Schloss Dagstuhl, 2010.
  published version (open access)

• [C8] J. Ketema, J.G. Simonsen, "Least Upper Bounds on the Size of Church-Rosser Diagrams in Term Rewriting and Lambda Calculus".
  Proceedings of the 10th International Symposium on Functional and Logic Programming (FLOPS '10). Lecture Notes in Computer Science 6009, p. 272--287. Springer Verlag, 2010.
  published version preliminary version

• [C7] S. Hedegaard, S. Houen, J.G. Simonsen, "LAIR: A Language for Automated Semantics-Aware Text Sanitization based on Frame Semantics".
  Proceedings of the 3rd IEEE International Conference on Semantic Computing (ICSC '09), p. 47--52. IEEE Computer Society 2009.
  published version

• [C6] J.G. Simonsen, "The Π ₀²-Completeness of most of the Properties of Rewriting You Care About (and Productivity)".
  Proceedings of the 20th International Conference on Rewriting Techniques and Applications (RTA '09). Lecture Notes in Computer Science 5595, p. 535--549. Springer Verlag, 2009.
  published version preliminary version

• [C5] J. Ketema, J.G. Simonsen, "On Confluence of Infinitary Combinatory Reduction Systems".
  Proceedings of the 12th International Conference on Logic for Programming, Artificial Intelligence and Reasoning (LPAR 2005). Lecture Notes in Artificial Intelligence 3835, p. 199--214, Springer-Verlag, 2005.
  published version preliminary version

• [C4] J.G. Simonsen, "On Beta-Shifts having Arithmetical Languages".
  Proceedings of the 30th International Symposium on Mathematical Foundations of Computer Science (MFCS 2005). Lecture Notes in Computer Science 3618, p. 757--768, Springer-Verlag, 2005.
  published version preliminary version

• [C3] J. Ketema, J.G. Simonsen, "Infinitary Combinatory Reduction Systems".
  Proceedings of the 16th International Conference on Rewriting Techniques and Applications (RTA 2005). Lecture Notes in Computer Science 3467, p. 438--452, Springer-Verlag, 2005.
  published version preliminary version

• [C2] J. Andersen, E. Elsborg, F. Henglein, J.G. Simonsen, C. Stefansen, "Compositional Specification of Commercial Contracts".
  Proceedings of the 1st International Symposium on Leveraging Applications of Formal Methods (ISOLA 2004). University of Cyprus Report TR-2004-6, 103-110. University of Cyprus 2005. (Superseded by [J6]).
  preliminary version

• [C1] J.G. Simonsen, "On the Modularity of Confluence in Infinitary Term Rewriting".
  Proceedings of the 15th International Conference on Rewriting Techniques and Applications (RTA 2004). Lecture Notes in Computer Science 3091, p.185-199, Springer-Verlag, 2004 (Superseded by [J4]).
  published version preliminary version
  Received the RTA 2004 Best Paper Award.

(Rigorously) peer-reviewed workshops

• [W2] L. Hartmann, N.D. Jones, J.G. Simonsen, "Programming in Biomolecular Computation". 1st International Workshop on Interactions between Computer Science and Biology (CS2Bio '10). Electronic Notes in Theoretical Computer Science 268, p. 97-114. Elsevier, 2010.
  published version preliminary version

• [W1] L. Hartmann, N.D. Jones, J.G. Simonsen, "Interpretive Overhead and Optimal Specialisation. Or: Life without the Pending List". First Workshop on Metacompuation in Russia (META 2008).

Invited papers and papers at lightly refereed workshops

• [A4] L. Hartmann, N.D. Jones, J.G. Simonsen, "Programming in Biomolecular Computation". Nordic Workshop in Programming Theory (NWPT '09) (Superseded, and vastly expanded and improved, by [W2]).

• [A3] M.I. Nielsen, K.F. Larsen, J.G. Simonsen, "Requirements for Logical Models for Value-Added Tax Legislation". Short paper session of the Conference on Logic for Programming, Artificial Intelligence and Reasoning (LPAR '08).

• [A2] F. Henglein, K.F. Larsen, J.G. Simonsen, C. Stefansen, "Compositional Contract Specification for REA". Invited paper for the First Workshop on Formal Languages and Analysis of Contract-Oriented Software (FLACOS 2007).

• [A1] J.G. Simonsen, "A Factorization Theorem in Higher-Order Rewriting with Application to Modular Reduction Semantics". Brazilian Symposium on Programming Languages (SBLP 2000).

Theses and technical reports

• [D3] J.G. Simonsen, "On Computable Approximation of Infinite Objects". PhD dissertation.

• [D2] J.G. Simonsen, "Higher-Order Rewriting with Applications to Impure Functional Languages". Speciale for the degree of cand. scient. (roughly equivalent to a master's thesis).

• [D1] B.M. Andersen, J.G. Simonsen, "Kuglefunktioner" (Eng. "Spherical Harmonics"). Bachelor's thesis, in Danish.

Teaching

Current teaching

Spring 2012: Supervision of theses and written projects at DIKU, the Department of Mathematical Sciences, and the cross-disciplinary programme in Communication and Information Technology.

Master's theses and graduate projects

Contact me directly.

Bachelor's theses

Contact me directly.

Previous teaching

• Lecturer (course head) in Human-Computer Interaction, fall 2010. Part of the DIKU undergraduate programme in computer science, the undergraduate programme in Communication and IT, and graduate programme in IT & Cognition. Course administrator fall 2011.
• Lecturer (course head) in Introduction to programming, fall 2009. Part of the DIKU undergraduate programme in computer science.
• Lecturer (course head, but Rasmus Jensen and Dina Friis did the actual work) in Grundlæggende datalogi, fall 2009, 2010. Part of the Faculty of Humanities' "Communication and IT" programme.
• Coordinator of the Human-Centered Computing project seminar, fall 2009, 2010, 2011.
• Lecturer in Data and Algorithms, part of the IT and Cognition programme at the Faculty of humanities, fall 2008.
• Lecturer (course head) in Introduction to programming, part of the IT and cognition programme and given jointly with the course IT and information retrieval at the Faculty of Humanities, fall 2007.
• Lecturer (course head) in Computability and complexity from a programming Perspective, spring 2007.
• Lecturer in Theory of science for computer scientists, spring 2007, 2008, 2009.
• Lecturer in Functional programming, fall 2005, fall 2006, fall 2007, fall 2008 (course head in 2008)
• Lecturer in IT and information retrieval (at the Center for Lang. Tech., Faculty of Humanities), fall 2006.
• Lecturer in Mathematics and computation, fall 2005.
• Lecturer (course head) in Computer-based mathematics and computation, fall 2003.
• Teaching assistant in Discrete mathematics, Mathematics and computation, V-Programming languages, V-Databases, 1997--2001, and report grader for Datalogi 0GB, 2000.

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Contact

Jakob Grue Simonsen
Department of Computer Science, University of Copenhagen (DIKU)
Universitetsparken 1, DK-2100 Copenhagen Ø, Denmark.


E-mail: simonsen-at-diku-dot-dk
Phone: (+45) 35 32 14 39
Fax: (+45) 35 32 14 01