Besides computer science I enjoy reading, walking, bicycle-riding,
visiting historical sites, travelling in general, taking photos (see some here, including photos of York and the university) and learning languages.
I also go to the cinema quite often
(I hate TV!) and miss the London theatres.
I'm a member of the outdoor society and the theatre society.
As the Lecturer [...] put it:
`He [the Archchancellor] called me in and asked me what I did, exactly.
Have you ever heard of such a thing?
What sort of question is that?
This is a university!'
And therefore education at the University mostly worked by the age-old method of putting a lot of young people in the vicinity of a lot of books and hoping that something would pass from one to the other, while the actual young people put themselves in the vicinity of inns and taverns for exactly the same reason.
Terry Pratchett, Interesting Times
`Students?' barked the Archchancellor.
`Yes, Master. You know? They're the thinner ones with the pale faces? Because we're a university? They come with the whole thing, like rats -'.
Terry Pratchett, Moving Pictures
`What sort of people would we be if we didn't go into the Library?'
`Students.'
Terry Pratchett, The Last Continent
Master thesis's (Diplomarbeiten) that I co-supervised at the RWTH Aachen
Ein Typprüfungsassistent für funktionale Programmiersprachen
Axel Simon, November 2000.
Koen Claessen, Colin Runciman, Olaf Chitil, John Hughes, Malcolm Wallace: Testing and Tracing Lazy Functional Programs using QuickCheck and Hat 4th Summer School in Advanced Functional Programming, Oxford, LNCS 2638, August 2003, pp. 59-99.
Olaf Chitil, Colin Runciman, and Malcolm Wallace: Transforming Haskell for Tracing Draft Proceedings of the 14th International Workshop on Implementation of Functional Languages, IFL 2002, Madrid, Spain, September 16-18; technical report 127-02, Departamento de Sistemas Informáticos y Programación, Universidad Complutense de Madrid, 2002, pp. 96-112. Abstract,
Pdf (159 KB)
Malcolm Wallace, Olaf Chitil, Thorsten Brehm, and Colin Runciman: Multiple-View Tracing for Haskell: a New Hat Preliminary Proceedings of the 2001 ACM SIGPLAN Haskell Workshop, Firenze, Italy, Universiteit Utrecht UU-CS-2001-23, 2 September 2001, pp. 151-170. Abstract,
Postscript (180 KB),
Pdf (179 KB),
Olaf Chitil, Colin Runciman and Malcolm Wallace: Freja, Hat and Hood - A Comparative Evaluation of Three Systems for Tracing and Debugging Lazy Functional Programs Markus Mohnen and Pieter Koopman (eds): Proceedings of the 12th International Workshop on Implementation of Functional Languages, Aachen, Germany, September 4th - 7th 2000, LNCS 2011, 2001, pp. 176-193. Abstract,
DVI (27 KB)
, Postscript (84 KB)
, Pdf (170 KB)
Olaf Chitil: Type-Inference Based Deforestation of Functional Programs PhD Thesis, RWTH Aachen, 2000, 157 pages. Abstract,
DVI (210 KB)
, Postscript (395 KB)
, Pdf (924 KB)
Olaf Chitil: Denotational Semantics for Teaching Lazy Functional Programming
Proceedings of the Workshop on
Functional and Declarative Programming in Education, Rice University Computer Science Technical Report TR99-346, 1999, page 27.
DVI (4 KB)
, Postscript (70 KB)
Olaf Chitil: Type Inference Builds a Short Cut to Deforestation ACM Sigplan Notices, 34(9):249-260, 1999.
Proceedings of the 1999 ACM SIGPLAN International Conference on Functional Programming (ICFP '99). Abstract
, DVI (40 KB)
, Postscript (660 KB)
This copy is posted by permission of ACM and may not be redistributed.
Olaf Chitil: Common Subexpression Elimination in a Lazy Functional Language Chris Clack, Tony Davie and Kevin Hammond (eds.): Proceedings of the 9th International Workshop on
Implementation of Functional Languages, St. Andrews, Scotland, September 10th-12th 1997, pp. 501-516.
Obsolete. See final LNCS proceedings. Abstract,
DVI (26 KB),
Postscript (51 KB).
Olaf Chitil: Adding an Optimisation Pass to the Glasgow Haskell Compiler Unpublished, also available from the GHC home page, November 4, 1997, 16 pages. Abstract,
DVI (17 KB),
Postscript (52 KB).
Olaf Chitil: The Sigma-Semantics:
A Comprehensive Semantics for Functional Programs Fundamenta Informaticae 31 (1997), IOS Press, pp. 253-294. Abstract,
DVI (81 KB, requires fonts of the XY-pic package),
Postscript (141 KB).
Olaf Chitil: The Sigma-Semantics:
A Comprehensive Semantics for Functional Programs Technical Report AIB 96-7, RWTH Aachen, 1996, 52 pages.
Obsolete. Pre-version of the Fundamenta Informaticae paper. Abstract,
DVI (82 KB, requires fonts of the XY-pic package),
Postscript (203 KB).
Olaf Chitil: Denotationelle und operationelle Semantiken für konstruktorbasierte funktionale Programmiersprachen erster Ordnung Master's Thesis, RWTH Aachen, 1995, 191 pages, in German.
Except for Chapters 6 to 8 about declarative definitions of the sigma-semantics, sequentiality, and non-free data types the paper The Sigma-Semantics:
A Comprehensive Semantics for Functional Programs is an improved presentation of the main points of my thesis.
Introduction: DVI, Postscript;
Complete Thesis:
DVI (270 KB, requires fonts of the XY-pic package),
Postscript (446 KB).
Werkzeuge zur Lokalisierung der Ursachen von Typfehlern in Programmen
Kolloquium des Instituts für Informatik und Praktische Mathematik,
Christian-Albrechts-Universität zu Kiel, Germany, 8 August 2003.
Abstract,
Folien (23): Postscript (110 KB), Pdf (92 KB).
Locating the Source of Type Errors
University of Kent at Canterbury,
11 July 2003.
Slides (13): Pdf (70 KB).
Tracen und Debuggen von Funktionalen Programmen mit verzögerter Auswertung
Lehrstuhl für Programmiersprachen,
Albert-Ludwigs-Universität Freiburg, Germany, 15 May 2002.
Abstract, Folien (25):
Postscript (786 KB), Pdf (729 KB).
Tracen und Debuggen von Funktionalen Programmen mit verzögerter Auswertung
Kolloquium des Instituts für Informatik und Praktische Mathematik,
Christian-Albrechts-Universität zu Kiel, Germany, 20 December 2001.
Abstract, Folien (20):
Postscript (596 KB), Pdf (545 KB).
Tracing and Debugging Haskell Programs with Hat
Theoretical Computer Science Group, University of Kent at Canterbury,
12 February 2001.
Abstract, Slides (23):
Postscript (678 KB), Pdf (607 KB).
Freja, Hat and Hood - A Comparative Evaluation of Three Systems for Tracing and Debugging Haskell Programs
Haskell Implementers' Workshop, Microsoft Research, Cambridge,
22 January 2001.
Tracing and Debugging of Lazy Functional Programs
Verification and Testing Research Group, University of Sheffield,
15 December 2000.
Abstract
Type-Inference Based Deforestation of Functional Programs
Informatik-Oberseminar, RWTH Aachen, Germany, 27 October 2000. Abstract, Folien (23):
Postscript (68 KB).
Freja, Hat and Hood - A Comparative Evaluation of Three Systems for Tracing and Debugging Lazy Functional Programs
12th International Workshop on Implementation of Functional Languages (IFL 2000), Aachen, Germany, 4 September 2000.
Slides (18):
Postscript (66 KB).
Deforestation of Functional Programs through Type Inference
17. Workshop der GI-Fachgruppe 2.1.4, Programmiersprachen und Rechenkonzepte mit Schwerpunkt Softwarekomponenten, Bad Honnef, Germany, 9 May 2000.
Deforestation von Funktionalen Programmen durch Typinferenz
Im Rahmen des Seminars zum Forschungsschwerpunkt Intelligente Formale Systeme. Technische Universität Dresden, 26 Januar 2000. Abstract,
Folien (23): Postscript (323 KB).
Type-Inference Based Short Cut Deforestation (nearly) without Inlining
11th International Workshop on Implementation of Functional Languages (IFL '99), Lochem, Netherlands, 7 September 1999.
Slides (19):
Postscript (356 KB).
Denotational Semantics for Teaching Lazy Functional Programming
Workshop on Functional and Declarative Programming in Education, Paris, France, 29 September 1999.
Slides (7):
Postscript (34 KB).
Type Inference Builds a Short Cut to Deforestation
1999 ACM SIGPLAN International Conference on Functional Programming (ICFP '99), Paris, France, 29 September 1999.
Slides (16):
Postscript (378 KB).
Common Subexpressions are Uncommon in Lazy Functional Languages
9th International Workshop on Implementation of Functional Languages (IFL '97), St. Andrews, Scotland, 12 September 1997.
Slides (15):
Postscript (38 KB).