Elmar Langetepe

Office	University of Bonn Institute of Computer Science, Dept. I Room N 313 Römerstr. 164 53117 Bonn		+49 (228) 73 - 4322
		Fax	+49 (228) 73 - 4321
			elmar.langetepe@informatik.uni-bonn.de
Consulting hours	By appointment

Research areas

• Computational Geometry
• Robot Motion Planning
• Online Algorithms

Publications

• Elmar Langetepe
  On the optimality of spiral search
  accepted for Proc. 21st Annu. ACM-SIAM Symp. Disc. Algor., 2010.

• Rolf Klein, Elmar Langetepe, Zhara Nilforoushan
  Abstract Voronoi Diagrams Revisited
  Computational Geometry: Theory and Applications 42(9), pp. 885-902, 2009.
  The original publication is available at Elsevier .

• Tom Kamphans, Elmar Langetepe
  Inspecting a set of strips optimally
  Abstracts 25th European Workshop Comput. Geom., Brussels, Belgium, 2009, pp. 163-166.
  Slides of the talk.

• Tom Kamphans, Elmar Langetepe
  Inspecting a set of strips optimally
  Algorithms and Data Structure Symposium, WADS, "Banff, Alberta, Canada" , 2009, pp. 423-434.
  Slides of the talk.

• Elmar Langetepe
  On the optimality of spiral search
  Abstracts 25th European Workshop Comput. Geom., Brussels, Belgium, 2009, pp. 329-332.
  Slides of the talk.

• Daniel Herrmann, Tom Kamphans, Elmar Langetepe
  Exploring Simple Triangular and Hexagonal Grid Polygons Online
  Abstracts 24th European Workshop Comput. Geom., Nancy, France, 2008, pp. 177-180.

• Tom Kamphans, Elmar Langetepe
  Leaving an unknown maze using an error-prone compass
  accepted for Internat. J. Comput. Geom. Appl., 2008.

• Rudolf Fleischer, Tom Kamphans, Rolf Klein, Elmar Langetepe, Gerhard Trippen
  Competitive online approximation of the optimal search ratio
  Siam J. Comput., pp. 881-898, 2008.

• Daniel Herrmann, Tom Kamphans, Elmar Langetepe
  Exploring Simple Triangular and Hexagonal Grid Polygons Online
  Technical Report 007, Department of Computer Science I, University of Bonn, 2007.

• Bernd Brüggemann, Tom Kamphans, Elmar Langetepe
  Leaving an Unknown Maze with One-Way Roads
  Abstracts 12th European Conf. Operational Research, Prague, 2007, pp. 140.

• Andrea Eubeler, Rudolf Fleischer, Tom Kamphans, Rolf Klein, Elmar Langetepe, Gerhard Trippen
  Searching for rays and lower bound constructions
  Abstracts 12th European Conf. Operational Research, Prague, 2007, pp. 65.

• Bernd Brüggemann, Tom Kamphans, Elmar Langetepe
  Escaping from a Labyrinth with One-way Roads for Limited Robots
  Abstracts 3rd European Conf. Mobile Robots, Freiburg, 2007.

• Bernd Brüggemann, Tom Kamphans, Elmar Langetepe
  Leaving an Unknown Maze with One-Way Roads
  Abstracts 23rd European Workshop Comput. Geom., Graz, Austria, 2007, pp. 90-93.

• Andrea Eubeler, Rudolf Fleischer, Tom Kamphans, Rolf Klein, Elmar Langetepe, Gerhard Trippen
  Competitive Online Searching for a Ray in the Plane
  Robot Navigation,
  Dagstuhl Seminar Proceedings , Internationales Begegnungs- und Forschungszentrum für Informatik (IBFI), Schloss Dagstuhl, Germany, 2006.

• Manuel Abellanas, Ferran Hurtado, Christian Icking, Rolf Klein, Elmar Langetepe, Lihong Ma, Belén Palop, Vera Sacristán
  The Farthest Color Voronoi Diagram and Related Problems
  Technical Report 002, Department of Computer Science I, University of Bonn, 2006.

• Elmar Langetepe, Gabriel Zachmann
  Geometric Data Structures for Computer Graphics
  A K Peters, Wellesley, Massachusetts, 2006.

• Tom Kamphans, Elmar Langetepe
  Optimal competitive online ray search with an error-prone robot
  Technical Report 003, Department of Computer Science I, University of Bonn, 2005.

• Christian Icking, Tom Kamphans, Rolf Klein, Elmar Langetepe
  Exploring grid polygons online
  Technical Report 001, Department of Computer Science I, University of Bonn, 2005.

• Tom Kamphans, Elmar Langetepe
  On optimizing multi-sequence functionals for competitive analysis
  Abstracts 21st European Workshop Comput. Geom., Eindhoven, 2005, pp. 111-114.

• Tom Kamphans, Elmar Langetepe
  Optimal competitive online ray search with an error-prone robot
  Proc. 4th Internat. Workshop Efficient Experim. Algorithms, Santorini,
  Lecture Notes Comput. Sci. 3503, Springer, 2005, pp. 593-596.
  © Springer-Verlag.

• Andrea Eubeler, Rudolf Fleischer, Tom Kamphans, Rolf Klein, Elmar Langetepe, Gerhard Trippen
  Competitive Online Searching for a Ray in the Plane
  Abstracts 21st European Workshop Comput. Geom., Eindhoven, 2005, pp. 107-110.

• Christian Icking, Tom Kamphans, Rolf Klein, Elmar Langetepe
  Exploring simple grid polygons
  11th Internat. Comput. Combin. Conf.,
  Lecture Notes Comput. Sci. 3595, Springer, 2005, pp. 524-533.
  © Springer-Verlag.

• Christian Icking, Rolf Klein, Elmar Langetepe, Sven Schuierer, Ines Semrau
  An Optimal Competitive Strategy for Walking in Streets
  SIAM J. Comput. 33, pp. 462-486, 2004.

• Tom Kamphans, Elmar Langetepe
  Finding a door along a wall with an error afflicted robot
  Abstracts 20th European Workshop Comput. Geom., Sevilla,
  Universidad de Sevilla, 2004, pp. 143-146.

• Annette Ebbers-Baumann, Rolf Klein, Elmar Langetepe, Andrzej Lingas
  A fast algorithm for approximating the detour of a polygonal chain
  Computational Geometry: Theory and Applications 27, pp. 123-134, 2004.

• Rudolf Fleischer, Tom Kamphans, Rolf Klein, Elmar Langetepe, Gerhard Trippen
  Competitive online approximation of the optimal search ratio
  Proc. 12th Annu. European Sympos. Algorithms, Bergen,
  Lecture Notes Comput. Sci. 3221, Springer-Verlag, 2004, pp. 335-346.
  © Springer-Verlag.

• Rudolf Fleischer, Tom Kamphans, Rolf Klein, Elmar Langetepe, Gerhard Trippen
  Competitive search ratio of graphs and polygons
  Abstracts 20th European Workshop Comput. Geom., Sevilla,
  Universidad de Sevilla, 2004, pp. 127-130.

• Roland Hagius, Christian Icking, Elmar Langetepe
  Lower bounds for the polygon exploration problem
  Abstracts 20th European Workshop Comput. Geom., Sevilla,
  Universidad de Sevilla, 2004, pp. 135-138.

• Ferran Hurtado, Rolf Klein, Elmar Langetepe, Vera Sacristán
  The weighted farthest color Voronoi diagram on trees and graphs
  Computational Geometry: Theory and Applications 27, pp. 13-26, 2004.

• Manuel Abellanas, Ferran Hurtado, Rolf Klein, Elmar Langetepe, Belen Palop, Vera Sacristán
  The bichromatic two center problem
  X Encuentros de Geometria Computacional, Sevilla,
  Universitat de Sevilla, 2003.

• Manuel Abellanas, Ferran Hurtado, Christian Icking, Rolf Klein, Elmar Langetepe, Lihong Ma, Belen Palop, Vera Sacristán
  Voronoi Diagram for services neighboring a highway
  Information Processing Letters 86, pp. 283-288, 2003.

• Tom Kamphans, Elmar Langetepe
  The Pledge Algorithm Reconsidered under Errors in Sensors and Motion
  Proc. of the 1th Workshop on Approximation and Online Algorithms,
  Lecture Notes Comput. Sci. 2909, Springer, 2003, pp. 165-178.
  © Springer-Verlag.

• Elmar Langetepe, Gabriel Zachmann
  Geometric Data Structures for Computer Graphics
  Tutorial presented at Siggraph 2003, San Diego, 2003.

• Ansgar Grüne, Rolf Klein, Elmar Langetepe
  Computing the Detour of Polygons
  Abstracts 19th European Workshop Comput. Geom., Bonn,
  University of Bonn, 2003, pp. 61-64.
  (Presentation File).

• Christian Icking, Thomas Kamphans, Rolf Klein, Elmar Langetepe
  On the competitive complexity of navigation tasks
  Sensor Based Intelligent Robots,
  Lecture Notes Comput. Sci. 2238, Springer, Berlin, 2002, pp. 245-258.
  © Springer-Verlag.

• Ferran Hurtado, Rolf Klein, Elmar Langetepe, Vera Sacristán
  The weighted farthest color voronoi diagram on trees and graphs.
  Abstracts 18th European Workshop Comput. Geom., Warsaw,
  Warsaw University, 2002, pp. 8-11.

• Ulrich Handel, Tom Kamphans, Elmar Langetepe, Wolfgang Meiswinkel
  Polyrobot -- an environment for simulating strategies for robot navigation in polygonal scenes
  Java Applet, 2002.

• Tom Kamphans, Elmar Langetepe
  Online Bewegungsplanung für Roboter
  Vorlesungsskript, Universität Bonn, Institut für Informatik, 2002.

• Elmar Langetepe, Gabriel Zachmann
  Geometric Data Structures for Computer Graphics
  Tutorial held at Eurographics 2002, Saarbrücken,
  MPI Saarbrücken, 2002.

• Manuel Abellanas, Ferran Hurtado, Christian Icking, Rolf Klein, Elmar Langetepe, Lihong Ma, Belén Palop, Vera Sacristán
  Smallest Color-Spanning Objects
  Technical Report 283, Department of Computer Science, FernUniversität Hagen, Germany, 2001.

• Oswin Aichholzer, Franz Aurenhammer, Christian Icking, Rolf Klein, Elmar Langetepe, Günter Rote
  Generalized Self-Approaching Curves
  Discrete Appl. Math. 109, pp. 3-24, 2001.

• Manuel Abellanas, Ferran Hurtado, Christian Icking, Elmar Langetepe, Rolf Klein, Lihong Ma, Belén Palop, Vera Sacristán
  Smallest Color-Spanning Objects
  In Proc. 9th Annual European Symposium on Algorithms, Lecture Notes in Computer Science 2161, Springer-Verlag, 2001, pp. 278-289.

• Annette Ebbers-Baumann, Rolf Klein, Elmar Langetepe, Andrzej Lingas
  A fast algorithm for approximating the detour of a polygonal chain
  Proc. 9th Annu. European Sympos. Algorithms,
  Lecture Notes Comput. Sci. 2161, Springer, Berlin, 2001, pp. 321-332.

• Manuel Abellanas, Ferran Hurtado, Christian Icking, Rolf Klein, Elmar Langetepe, Lihong Ma, Belén Palop, Vera Sacristán
  The Farthest Color Voronoi Diagram and Related Problems
  Abstracts 17th European Workshop Comput. Geom., Berlin,
  Freie Universität Berlin, 2001, pp. 113-116.

• Manuel Abellanas, Ferran Hurtado, Christian Icking, Rolf Klein, Elmar Langetepe, Lihong Ma, Belén Palop, Vera Sacristán
  Smallest Color-Spanning Objects
  Proc. 9th Annu. European Sympos. Algorithms, 2001.

• Manuel Abellanas, Ferran Hurtado, Christian Icking, Rolf Klein, Elmar Langetepe, Lihong Ma, Belen Palop, Vera Sacristán
  Proximity problems for time metrics induced by the L₁-metric and isothetic networks
  IX Encuentros en Geometri a Computacional, Girona,
  Universitat de Girona, 2001, pp. 175-181.

• Ulrich Handel, Christian Icking, Tom Kamphans, Elmar Langetepe, Wolfgang Meiswinkel
  Gridrobot -- an environment for simulating exploration strategies in unknown cellular areas
  Java Applet, 2000.

• Christian Icking, Thomas Kamphans, Rolf Klein, Elmar Langetepe
  Exploring an Unknown Cellular Environment
  Abstracts 16th European Workshop Comput. Geom., Eilat,
  Ben-Gurion University of the Negev, 2000, pp. 140-143.

• Christian Icking, Thomas Kamphans, Rolf Klein, Elmar Langetepe
  Exploring an Unknown Cellular Environment
  Unpublished Manuscript, FernUniversität Hagen, 2000.

• Elmar Langetepe
  Design and Analysis of Strategies for Autonomous Systems in Motion Planning
  Department of Computer Science, FernUniversität Hagen, 2000.

• Christoph Hipke, Christian Icking, Rolf Klein, Elmar Langetepe
  How to Find a Point on a Line within a Fixed Distance
  Discrete Appl. Math. 93, pp. 67-73, 1999.

• Christian Icking, Rolf Klein, Elmar Langetepe
  Self-Approaching Curves
  Math. Proc. Camb. Phil. Soc. 125, pp. 441-453, 1999.

• Christian Icking, Peter Köllner, Elmar Langetepe
  Simulating online exploration in rectilinear scenes
  Java Applet, 1999.

• Christian Icking, Rolf Klein, Elmar Langetepe
  Searching a Goal on m Rays Within a Fixed Distance
  Abstracts 15th European Workshop Comput. Geom., Antibes,
  INRIA Sophia-Antipolis, 1999, pp. 137-139.

• Christian Icking, Rolf Klein, Elmar Langetepe
  An Optimal Competitive Strategy for Walking in Streets
  Proc. 16th Sympos. Theoret. Aspects Comput. Sci., Trier,
  Lecture Notes Comput. Sci. 1563, Springer-Verlag, 1999, pp. 110-120.

• Christian Icking, Rolf Klein, Elmar Langetepe
  An Optimal Competitive Strategy for Walking in Streets
  Technical Report 233, Department of Computer Science, FernUniversität Hagen, Germany, 1998.

• Oswin Aichholzer, Franz Aurenhammer, Christian Icking, Rolf Klein, Elmar Langetepe, Günter Rote
  Generalized Self-Approaching Curves
  Proc. 9th Annu. Internat. Sympos. Algorithms Comput., Taejon,
  Lecture Notes Comput. Sci. 1533, Springer-Verlag, 1998, pp. 317-326.

• Oswin Aichholzer, Franz Aurenhammer, Christian Icking, Rolf Klein, Elmar Langetepe, Günter Rote
  Generalized Self-Approaching Curves
  Abstracts 14th European Workshop Comput. Geom., Barcelona,
  Universitat Polytènica de Catalunya, Barcelona, 1998, pp. 15-17.

• Oswin Aichholzer, Franz Aurenhammer, Christian Icking, Rolf Klein, Elmar Langetepe, Günter Rote
  phi-Self-Approaching Curves
  Technical Report 226, Department of Computer Science, FernUniversität Hagen, Germany, 1997.

• Christoph Hipke, Christian Icking, Rolf Klein, Elmar Langetepe
  How to Find a Point on a Line within a Fixed Distance
  Technical Report 220, Department of Computer Science, FernUniversität Hagen, Germany, 1997.

• Christian Icking, Rolf Klein, Elmar Langetepe
  Self-Approaching Curves
  Technical Report 217, Department of Computer Science, FernUniversität Hagen, Germany, 1997.

• Christian Icking, Rolf Klein, Elmar Langetepe
  Searching for the Kernel of a Polygon: A Competitive Strategy Using Self-Approaching Curves
  Technical Report 211, Department of Computer Science, FernUniversität Hagen, Germany, 1997.

• G. Antoniou, E. Langetepe
  A correct logic programming computation of default logic extensions
  Journal of Automated Reasoning 18,1, pp. 25-46, 1997.

• G. Antoniou, E. Langetepe
  Applying SLD-resolution to a Class of Non-Horn Logic Programs
  Journal of the Interest Group of Pure and Applied Logics 2,2, pp. 229-241, 1994.

• G. Antoniou, E. Langetepe, V. Sperschneider
  New proofs in default logic theory
  Annals of Mathematics and Artificial Intelligence 12, pp. 215-229, 1994.

• G. Antoniou, E. Langetepe
  Soundness and Completeness of a Logic Programming Approach to Default Logic
  Proc. American National Conference on Artificial Intelligence,
  MIT Press, 1994, pp. 934-939.

• E. Langetepe
  Betrachtung einzelner Default-Logik Ansätze unter Verwendung eines operationalen Extensionenmodells
  Diploma thesis, Department of Mathematics and Computer Science, University of Osnabrück, 1994.

• E. Langetepe, V. Sperschneider
  Some Applications of the Concept of Processes in Default Logic
  In Schwerpunktband Nichtmonotones Schließen,
  edited by Ch. Habel, LNAI , Springer, 1994.

• G. Antoniou, E. Langetepe
  A Process Model for Default Logics and its Realization in Logic Programming
  In Proc. 4th Portugese Conference on Artificial Intelligence,
  LNAI , Springer, 1993, pp. 213-225.