Priv.-Doz. Dr. Elmar Langetepe

Erasmusprogramm Informatik

• Algorithmic
• Computational Geometry
• Algorithmic Motion Planning
• Online Algorithms

Research topics: Surveillance, VC-Dimension, Geometric-Fire-Fighting, Competitive-Complexity

• Lecture Bachelor: Logic and discrete Structures
• Master: Practical Course Computational Geometry (Lab)
• Bachelorthesis-Seminar
• Masterthesis-Seminar

• Lecture Master: Online Motion Planning
• Lecture Bachelor: Foundations of Computational Geometry
• Project and Practical Courses Computational Geometry (Lab/Pg)
• Bachelorthesis-Seminar
• Masterthesis-Seminar

Workshop on Search Games: Theory and Algorithms (Lorentz Center Leiden June 27th to July 1st, 2016)

See also DBLP

• Sang-Sub Kim, Rolf Klein, David Kübel, Elmar Langetepe, Barbara Schwarzwald
  Geometric Firefighting in the Half-plane
  Algorithms and Data Structures Symposium WADS, 2019.

• Rolf Klein, Elmar Langetepe, Christos Levcopoulos, Andrzej Lingas, Barbara Schwarzwald
  On a fire fighter's problem
  Int. J. Foundations of Computer Science, 2019.

• Herman Haverkort, David Kübel, Elmar Langetepe, Barbara Schwarzwald
  How to play hot and cold on a line
  Computational Geometry – Theory and Applications, accepted for publication , 2018.

• Rolf Klein, David Kübel, Elmar Langetepe, Barbara Schwarzwald
  Protecting a highway from fire
  34th European Workshop on Computational Geometry, EuroCG, 2018.

• Martin Kretschmer, Elmar Langetepe
  Evolutionary learning of fire fighting strategies
  13th Biennial International Conference on Artificial Evolution, 2017.

• Elmar Langetepe, Bengt Nilsson, Eli Packer
  Discrete Surveillance Tours in Polygonal Domains,
  29th Canadian Conference on Computational Geometry CCCG, 2017.

• Elmar Langetepe, Simone Lehmann
  Exact VC-dimension for L1-visibility of points in simple polygons, arXiv Preprint 2017.

• Martin Kretschmer, Elmar Langetepe
  Evolutionary learning of fire fighting strategies, arXiv Preprint 2017.

• Herman Haverkort, David Kübel, Elmar Langetepe, Barbara Schwarzwald
  How to play hot and cold on a line
  Algorithms and Data Structures Symposium WADS, 2017.

• Herman Haverkort, David Kübel, Elmar Langetepe, Barbara Schwarzwald
  How to play hot and cold on a line
  33rd European Workshop Comput. Geom., Malmö, Sweden, 2017.

• Rolf Klein, Elmar Langetepe
  Computational Geometry Column 63
  SIGACT News, 2016.

• Elmar Langetepe, David Kübel
  Optimal online escape path against a certificate
  Symposium and Workshops on Algorithm Theory, SWAT, 2016.
  Slides of the talk.

• Rolf Klein, David Kriesel, Elmar Langetepe
  A local strategy for cleaning expanding cellular domains by simple robots
  Theoretical Computer Science, 2015.

• Elmar Langetepe, Andreas Lenerz, Bernd Brüggemann
  Strategic deployment in graphs
  Informatica, Vol 39, No 3, 237–247, 2015.

• Rolf Klein, Elmar Langetepe, Christos Levcopoulos
  A Fire Figther's Problem
  Symposium on Computational Geometry, SoCG 2015.
  Slides of the talk (Videos inside, incorporate media player).

• Elmar Langetepe, Robotics, Encyclopedia of Algorithms, 2015.
  

• Rolf Klein, David Kriesel, Elmar Langetepe
  A local strategy for cleaning expanding cellular domains by simple robots, arXiv Preprint 2015.

• Elmar Langetepe, Andreas Lenerz, Bernd Brüggemann
  Strategic deployment in graphs, arXiv Preprint 2014.

• Rolf Klein, Elmar Langetepe, Christos Levcopoulos
  A Fire Figther's Problem, Full Version, arXiv Preprint 2014.

• Bernd Brüggemann, Elmar Langetepe, Andreas Lenerz
  Strategic deployment in graphs
  MATCOS, Koper 2013.
  Slides of the talk.

• Rolf Klein, David Kriesel, Elmar Langetepe
  A truly local strategy for ant robots cleaning expamding domains
  29th European Workshop Comput. Geom., Braunschweig, Germany, 2013.

• Elmar Langetepe
  Searching for an axis-parallel shoreline
  Theoretical Computer Science, 447, pp. 85-99, 2012.

• Christian Wulff-Nilsen, Ansgar Grüne, Rolf Klein, Elmar Langetepe, D. T. Lee, Tien-Ching Lin, Sheung-Hung Poon, Teng-Kai Yu
  Computing the stretch factor and maximum detour of paths, trees and cycles in the normed space
  Int. J. Comput. Geom. Appl. 22, 45, 2012.

• Bernd Brüggemann, Elmar Langetepe, Andreas Lenerz, Dirk Schulz
  From a Multi-robot Global Plan to Single-robot Actions
  ICINCO (2), 419-422, 2012

• Elmar Langetepe
  Optimizing two-sequence functionals for competitive analysis
  Computer Science - Research and Development 27(3), pp. 207-216, 2012

• Thilo Beckmann, Rolf Klein, David Kriesel, Elmar Langetepe
  Ant-sweep: a decentral strategy for cooperative cleaning in expanding domains
  Symposium on Computational Geometry, pp. 287-288, Paris 2011.

• Rolf Klein, Marcus Krug, Elmar Langetepe, D.T. Lee, Dorothea Wagner
  Constructing Optimal Shortcuts in Directed Weighted Paths
  27th European Workshop Comput. Geom., Morschach, Switzerland, 2011.

• Rudolf Fleischer, Thomas Kamphans, Rolf Klein, Elmar Langetepe, Gerhard Trippen
  The Tourist in the Shopping Arcade
  Journal of Universal Computer Science 16(5), pp. 676-685, 2010.

• Elmar Langetepe
  Searching for an axis-parallel shoreline
  COCOA 2010, Int. Conf. on Combinatorial Optimization and Applications, LNCS 6508,
  Springer-Verlag, 2010, pp. 369-384.
  Slides of the talk.

• Ansgar Grüne, Tien-Ching Lin, Teng-Kai Yu, Rolf Klein, Elmar Langetepe, D.T. Lee, Sheung-Hung Poon
  Maximum Detour and Spanning Ratio on Rectilinear Path in L1 Plane
  “ISAAC 2010, Internat. Sympos. Algorithms Comput.” , 2010, pp. 121-131.

• Elmar Langetepe, Rainer Penninger, Jan Tulke
  Computing the visibility area between two simple polygons in linear time
  Abstracts 26th European Workshop Comput. Geom., Dortmund, 2010, pp. 237-240.

• Elmar Langetepe
  On the optimality of spiral search
  SODA 2010: Proc. 21st Annu. ACM-SIAM Symp. Disc. Algor., 2010, pp. 1-12.
  Slides of the talk.

• Tom Kamphans, Elmar Langetepe
  Leaving an unknown maze using an error-prone compass
  Internat. J. Comput. Geom. Appl. 20, pp. 307-325, 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
  WADS 2009: Algorithms and Data Structure Symposium, “Banff, Alberta, Canada” , 2009, pp. 423-434.
  Slides of the talk.

• 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.

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

• Tom Kamphans, Elmar Langetepe, Rolf Klein
  Offline Bewegungsplanung
  Vorlesungsskript, Universität Bonn, Institut für Informatik, 2009.

• 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.

• 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 23rd European Workshop Comput. Geom., Graz, Austria, 2007, pp. 90-93.

• 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 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• 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).

• 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.

• 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.

• 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.

• 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.

• 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.

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

• 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, 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.

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

• 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, 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.

• 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.

• 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.

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

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

• Ulrich Handel, Christian Icking, Tom Kamphans, Elmar Langetepe, Wolfgang Meiswinkel
  Gridrobot – an environment for simulating exploration strategies in unknown cellular areas, 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
  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
  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
  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, 1999.

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

• 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.

• 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.

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

• 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.