research topics, publications, grants?

Research Topics

Geometric Shape Matching is an important ingredient in shape retrieval, recognition and classification, alignment and registration, and approximation and simplification. In a large database of shapes, for example, shape retrieval searches for all shapes similar to a query shape.

Shape Approximation: Substituting a complex geometric shape by a "simpler" one is motivated by many applications. A typical example is the problem of computing the smallest (area) enclosing disc (or annulus, square, ...) of a given set of points in d-dimensional Euclidean space. Unfortunately many of these problems turn out to be computationally difficult. Many of them are NP-hard, and for many others the best known solutions have polynomial runtimes of high degree which renders these algorithms uninteresting from a practical point of view. A possible solution is that instead of insisting on computing the exact solution for such an optimization problem, one looks for a solution that approximates the optimum reasonably well.

Skyline queries have gained much attention lately in database and data mining communities, as formulating such queries is rather intuitive compared to other types of queries, for example, ranking. However, not much has been known about Spatial Skyline Queries, skyline queries on massive spatial data. We study spatial skyline query processing problem, which enables an intelligent and efficient access to massive spatial data.

In Casting, liquid is poured into a cast that has a cavity with the shape of the object to be manufactured. The liquid then hardens, after which the cast is removed and one is left with an object whose shape is that of the cavity. The key property necessary for casting is that the cast parts can be removed from the object without destroying either the cast parts or the object. This ensures that the given object can be mass produced by re-using the same cast parts.

Research Publications

International Journal articles

  1. Hee-Kap Ahn, Jessica Sherette, Sang Duk Yoon.
    Realistic Roofs over a Rectilinear Polygon Revisited.
    Submitted (on invitation)
  2. Hee-Kap Ahn, Hyo-Sil Kim, Sang-Sub Kim, Wanbin Son.
    Computing k centers over Streaming Data for Small k.
    Submitted
  3. Hee-Kap Ahn, Sang Won Bae, Otfried Cheong, Joachim Gudmundsson, Takeshi Tokuyama, Antoine Vigneron.
    A Generalization of the Convex Kakeya Problem.
    To appear in Algorithmica (on invitation, LATIN 2012)
    arXiv:1209.2171
  4. Wanbin Son, Seung-won Hwang, Hee-Kap Ahn.
    MSSQ: Manhattan Spatial Skyline Queries.
    Information Systems 40, pages 67-83, 2014
  5. Hee-Kap Ahn, Siu-Wing Cheng, Hyuk Jun Kweon, Juyoung Yon.
    Overlap of Convex Polytopes under Rigid Motion.
    Computational Geometry: Theory and Applications 47(1), pages 15-24, 2014
  6. Hee-Kap Ahn, Sang Won Bae, Christian Knauer, Mira Lee, Chan-Su Shin, Antoine Vigneron.
    Realistic Roofs over a Rectilinear Polygon.
    Computational Geometry: Theory and Applications 46(9), pages 1042-1055, 2013
  7. Hee-Kap Ahn, Siu-Wing Cheng, Iris Reinbacher.
    Maximum Overlap of Convex Polytopes under Translation.
    Computational Geometry: Theory and Applications, a special issue on "Geometric Optimization". 46(5), pages 552-565, 2013
  8. Hee-Kap Ahn, Sang-Sub Kim, Christian Knauer, Lena Schlipf, Chan-Su Shin, Antoine Vigneron.
    Covering and Piercing Disks with Two Centers.
    Computational Geometry: Theory and Applications, 46(3), pages 253-262, 2013
    arXiv:1201.1198
  9. Hee-Kap Ahn, Christian Knauer, Marc Scherfenberg, Lena Schlipf, Antoine Vigneron.
    Computing the Discrete Fréchet Distance with Imprecise Input.
    International Journal of Computational Geometry and Applications, 22(1), pages 27-44, 2012 (on invitation, ISAAC 2010)
    Manuscript available.
  10. Hee-Kap Ahn, Otfried Cheong.
    Aligning two convex figures to minimize area or perimeter.
    Algorithmica, 62(1-2), pages 464-479, 2012
    Manuscript available.
  11. Hee-Kap Ahn, Otfried Cheong, Jiri Matousek, Antoine Vigneron.
    Reachability by paths of bounded curvature in a convex polygon.
    Computational Geometry: Theory and Applications, 45(1-2), pages 21-32, 2012
    arXiv:1008.4244
  12. Hee-Kap Ahn, Sang Won Bae, Marc van Kreveld, Iris Reinbacher, Bettina Speckmann.
    Empty Pseudo-Triangles in Point Sets.
    Discrete Applied Mathematics, 159(18), pages 2205-2213, 2011
    Manuscript available.
  13. Mu-Woong Lee, Wanbin Son, Hee-Kap Ahn, Seung-won Hwang.
    Spatial Skyline Queries: Exact and Approximation Algorithms.
    GeoInformatica, 15(4), pages 665-697, 2011. (on invitation, SSTD 2009 Best Paper)
    arXiv:0903.3072
  14. Sang-Sub Kim, Sang Won Bae, Hee-Kap Ahn.
    Covering a Point Set by Two Disjoint Rectangles.
    International Journal of Computational Geometry and Applications, 21(3), pages 313-330, 2011. (on invitation, ISAAC 2008)
    Manuscript available.
  15. Hee-Kap Ahn, Sang Won Bae, Erik D. Demaine, Martin L. Demaine, Sang-Sub Kim, Mathias Korman, Iris Reinbacher, Wanbin Son.
    Covering Points by Disjoint Boxes with Outliers.
    Computational Geometry: Theory and Applications, 44(3), pages 178-190, 2011.
    arXiv:0910.1643
  16. Hee-Kap Ahn, Yoshio Okamoto.
    Adaptive Algorithms for Planar Convex Hull Problems.
    IEICE Transactions on Information and Systems E94-D(2), pages 182-189, 2011
    Manuscript available.
  17. Hee-Kap Ahn, Peter Brass, Christian Knauer, Hyeon-Suk Na, Chan-Su Shin.
    Covering a Simple Polygon by Monotone Directions.
    Computational Geometry: Theory and Applications 43(5), pages 514-523, 2010
    Manuscript available.
  18. Hee-Kap Ahn, Mohammad Farshi, Christian Knauer, Michiel Smid, Yajun Wang.
    Dilation-Optimal Edge Deletion in Polygonal Cycles.
    International Journal of Computational Geometry and Applications, 20(1), pages 69-87, 2010. (on invitation, ISAAC 2007)
    Manuscript available.
  19. Sang Won Bae, Chunseok Lee, Hee-Kap Ahn, Sunghee Choi, Kyung-Yong Chwa.
    Computing Minimum-Area Rectilinear Convex Hull and L-Shape.
    Computational Geometry: Theory and Applications, 42(9), pages 903-912, 2009
    Manuscript available.
  20. Hee-Kap Ahn, Sang Won Bae, Siu-Wing Cheng, Kyung-Yong Chwa.
    Casting an Object with a Core.
    Algorithmica 54(1), pages 72-88, 2009
    Manuscript available.
  21. Hee-Kap Ahn, Helmut Alt, Tetsuo Asano, Sang Won Bae, Peter Brass, Otfried Cheong, Christian Knauer, Hyeon-Suk Na, Chan-Su Shin, Alexander Wolff.
    Constructing Optimal Highways.
    International Journal of Foundations of Computer Science 20(1), pages 3-23, 2009 (on invitation, CATS 2007)
    arxiv:cs.CG/0703037
  22. Hee-Kap Ahn, Peter Brass, Hyeon-Suk Na, Chan-Su Shin.
    On the Minimum Size of Systems of Building Blocks Expressing all Intervals, and Range-Restricted Queries.
    Computational Geometry: Theory and Applications 42(3), pages 207-213, 2009
    Manuscript available.
  23. Hee-Kap Ahn, Sang Won Bae, Otfried Cheong, Joachim Gudmundsson.
    Aperture-Angle and Hausdorff-Approximation of Convex Figures.
    Discrete & Computational Geometry 40(3), pages 414-429, 2008
    arxiv:cs.CG/0702090
  24. Hee-Kap Ahn, Peter Brass, Chan-Su Shin.
    Maximum Overlap and Minimum Convex Hull of Two Convex Polyhedra under Translations.
    Computational Geometry: Theory and Applications 40, pages 171-177, 2008
  25. Hee-Kap Ahn, Otfried Cheong, Chong-Dae Park, Chan-Su Shin, Antoine Vigneron.
    Maximizing the Overlap of Two Planar Convex Sets under Rigid Motions.
    Computational Geometry: Theory and Applications 37, pages 3-15, 2007 (on invitation, ACM SoCG 2005)
    Manuscript available.
  26. Hee-Kap Ahn, Siu-Wing Cheng, Otfried Cheong.
    Casting with Skewed Ejection Direction.
    Algorithmica 44(4), pages 325-342, 2006
    Manuscript available.
  27. Hee-Kap Ahn, Peter Brass, Otfried Cheong, Hyeon-Suk Na, Chan-Su Shin, Antoine Vigneron.
    Inscribing an Axially Symmetric Polygon and other Approximation Algorithms for Planar Convex Sets.
    Computational Geometry: Theory and Applications 33(3), pages 152-164, 2006
    Manuscript available.
  28. Hee-Kap Ahn, Siu-Wing Cheng, Otfried Cheong, Jack Snoeyink.
    The Reflex-Free Hull.
    International Journal of Computational Geometry and Applications 14(6), pages 453-474, 2004
  29. Hee-Kap Ahn, Siu-Wing Cheng, Otfried Cheong, Mordecai Golin, René van Oostrum.
    Competitive Facility Location: The Voronoi Game.
    Theoretical Computer Science 310(1-3), pages 457-467, 2004
    Available as Technical Report UU-CS-2001-45.
  30. Hee-Kap Ahn, Otfried Cheong, René van Oostrum.
    Casting a Polyhedron with Directional Uncertainty.
    Computational Geometry: Theory and Applications 26(2), pages 129-141, 2003
    Available as Technical Report UU-CS-2001-48.
  31. Hee-Kap Ahn, Otfried Cheong, Chan-Su Shin.
    Building Bridges between Convex Regions.
    Computational Geometry: Theory and Applications 25(1/2), pages 161-170, 2003
    Available as Technical Report UU-CS-2001-46.
  32. Hee-Kap Ahn, Mark de Berg, Prosenjit Bose, Siu-Wing Cheng, Dan Halperin, Jiri Matousek, Otfried Schwarzkopf.
    Separating an Object from its Cast.
    Computer-Aided Design (CAD) 34(8), pages 547-559, 2002
  33. Hee-Kap Ahn, Prosenjit Bose, Jurek Czyzowicz, Nicolas Hanusse, Evangelos Kranakis, Pat Morin.
    Flipping your Lid.
    Geombinatorics X(2), pages 57-63, 2000
    Available as Technical Report UU-CS-2001-13 at Utrecht university.

Domestic journal articles

  1. Hee-Kap Ahn, Sang Won Bae, Otfried Cheong.
    A geometric proof on shortest paths of bounded curvature.
    In KISS journal 34(4), pages 132-137, 2007
  2. Hee-Kap Ahn, Chan-Su Shin.
    Minimum Diameter Spanning Tree with Bounded Degree.
    In KISS Journal 31(2), pages 78-85, 2004
  3. Heedong Ko, Hee-Kap Ahn, Jin-Wook Kim, Jong-Guk Kim, Jae-Bok Song, Hong-Jun Eu, Myung-Whan Yun, In-Su Woo, Yeon-Dong Park.
    Evaluation of Car Prototype using CAVE-like Systems.
    In KSES Journal 5(4), pages 77-84, 2002

Refereed International Conference Proceedings

  1. Sang-Sub Kim, Hee-Kap Ahn.
    An Improved Data Stream Algorithm for Clustering.
    Accepted for presentation at 11th Latin American Theoretical Informatics Symposium (LATIN 2014)
  2. Wanbin Son, Fabian Stehn, Christian Knauer, Hee-Kap Ahn.
    Top-k Manhattan Spatial Skyline Queries.
    To appear in Proc. 8th International Workshop on Algorithms and Computation (WALCOM 2014), 2014
  3. Hee-Kap Ahn, Helmut Alt, Sang Won Bae, Dongwoo Park.
    Bundling Three Convex Polygons to Minimize Area or Perimeter.
    In Proc. 13th Algorithms and Data Structures Symposium (WADS 2013), pages 13-24, 2013.
  4. Hee-Kap Ahn, Sang Won Bae, Wanbin Son.
    Group Nearest Neighbor Queries in the L1 Plane.
    In Proc. 10th Annual Conference on Theory and Applications of Models of Computation (TAMC 2013), pages 52-61, 2013.
  5. Hee-Kap Ahn, Siu-Wing Cheng, Hyuk Jun Kweon, Juyoung Yon.
    Overlap of Convex Polytopes under Rigid Motion.
    In Proc. 32nd IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2012), pages 498-509, 2012.
  6. Hee-Kap Ahn, Hyo-Sil Kim, Sang-Sub Kim, Wanbin Son.
    Computing k-center over Streaming Data for Small k.
    In Proc. 23rd International Symposium on Algorithms and Computation (ISAAC 2012), pages 54-63, 2012.
  7. Hee-Kap Ahn, Sang Won Bae, Shin-Ichi Tanigawa.
    Rectilinear Covering for Imprecise Input Points.
    In Proc. 23rd International Symposium on Algorithms and Computation (ISAAC 2012), pages 309-318, 2012.
  8. Yoonho Hwang, Bohyung Han, Hee-Kap Ahn.
    A Fast Nearest Neighbor Search Algorithm by Nonlinear Embedding.
    In Proc. 25th IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2012), pages 3053-3060, 2012.
  9. Hee-Kap Ahn, Sang Won Bae, Otfried Cheong, Joachim Gudmundsson, Takeshi Tokuyama.
    A Generalization of the Convex Kakeya Problem.
    In Proc. 10th Latin American Theoretical Informatics Symposium (LATIN 2012), pages 1-12, 2012.
  10. Yoonho Hwang, Hee-Kap Ahn.
    Convergent Bounds on the Euclidean Distance.
    In Proc. 25th Annual Conference on Neural Information Processing Systems (NIPS 2011), pages 388-396, 2011
  11. Hee-Kap Ahn, Sang-Sub Kim, Christian Knauer, Lena Schlipf, Chan-Su Shin, Antoine Vigneron.
    Covering and Piercing Disks with Two Centers.
    In Proc. 22nd International Symposium on Algorithms and Computation (ISAAC 2011), pages 50-59, 2011.
  12. Hee-Kap Ahn, Sang Won Bae, Christian Knauer, Mira Lee, Chan-Su Shin, Antoine Vigneron.
    Generating Realistic Roofs over a Rectilinear Polygon.
    In Proc. 22nd International Symposium on Algorithms and Computation (ISAAC 2011), pages 60-69, 2011.
  13. Wanbin Son, Seung-won Hwang, Hee-Kap Ahn.
    MSSQ: Manhattan Spatial Skyline Queries., pages 313-329, 2011.
    In Proc. 12th Symposium on Spatial and Temporal Databases (SSTD 2011)
  14. Hee-Kap Ahn, Christian Knauer, Marc Scherfenberg, Lena Schlipf, Antoine Vigneron.
    Computing the Discrete Fréchet Distance with Imprecise Input.
    In Proc. 21st International Symposium on Algorithms and Computation (ISAAC 2010), LNCS 6507, pages 422-433, 2010.
  15. Hee-Kap Ahn, Siu-Wing Cheng, Iris Reinbacher.
    Maximum Overlap of Convex Polytopes under Translation.
    In Proc. 21st International Symposium on Algorithms and Computation (ISAAC 2010), LNCS 6507, pages 97-108, 2010.
  16. Hee-Kap Ahn, Yoshio Okamoto.
    Adaptive Algorithms for Planar Convex Hull Problems.
    In Proc. 4th International Frontiers of Algorithms Workshop (FAW 2010), LNCS 6213, pages 316-326, 2010.
  17. Wanbin Son, Mu-Woong Lee, Hee-Kap Ahn, Seung-won Hwang.
    Spatial Skyline Queries: An Efficient Geometric Algorithm. (Best Paper Award)
    In Proc. 11th International Symposium on Spatial and Temporal Databases (SSTD 2009), LNCS 5644, pages 247-264, 2009.
  18. Hee-Kap Ahn, Sang Won Bae, Sang-Sub Kim, Matias Korman, Iris Reinbacher, Wanbin Son.
    Square and Rectangle Covering with Outliers.
    In Proc. 3rd International Frontiers of Algorithms Workshop (FAW 2009)., LNCS 5598, pages 132-140, 2009.
    A shorter version has been presented at 25th European Workshop on Computational Geometry 2009.
  19. Hee-Kap Ahn, Sang Won Bae, Iris Reinbacher.
    Optimal Empty Pseudo-Triangles in a Point Set.
    In Proc. 21st Canadian Conference on Computational Geometry (CCCG 2009), 2009.
  20. Hee-Kap Ahn, Sang Won Bae.
    Covering a Point Set by Two Disjoint Rectangles.
    In Proc. 19th Annual International Symposium on Algorithms and Computation (ISAAC 2008), LNCS 5369, pages 728-739, 2008
  21. Hee-Kap Ahn, Peter Brass, Christian Knauer, Hyeon-Suk Na, Chan-Su Shin.
    Covering a Simple Polygon by Monotone Directions.
    In Proc. 19th Annual International Symposium on Algorithms and Computation (ISAAC 2008), LNCS 5369, pages 668-679, 2008
  22. Hee-Kap Ahn, Mohammad Farshi, Christian Knauer, Michiel Smid, Yajun Wang.
    Dilation-optimal edge deletion in polygonal cycles.
    In Proc. 18th Annual International Symposium on Algorithms and Computation (ISAAC 2007), LNCS 4835, pages 88-99, 2007
  23. Sang Won Bae, Chunseok Lee, Hee-Kap Ahn, Sunghee Choi, Kyung-Yong Chwa.
    Maintaining Extremal Points and Its Applications to Deciding Optimal Orientations.
    In Proc. 18th Annual International Symposium on Algorithms and Computation (ISAAC 2007), LNCS 4835, pages 788-799, 2007
  24. Hee-Kap Ahn, Sang Won Bae, Otfried Cheong, Joachim Gudmundsson.
    Aperture-Angle and Hausdorff-Approximation of Convex Figures.
    In Proc. 23rd Annual ACM Symposium on Computational Geometry (SoCG 2007), pages 37-45, 2007
  25. Hee-Kap Ahn, Helmut Alt, Tetsuo Asano, Sang Won Bae, Peter Brass, Otfried Cheong, Christian Knauer, Hyeon-Suk Na, Chan-Su Shin, Alexander Wolff.
    Constructing Optimal Highways.
    In Proc. Computing: The Australasian Theory Symposium (CATS 2007), CRPIT Vol.65, pages 7-14, 2007
  26. Hee-Kap Ahn, Sang Won Bae, Siu-Wing Cheng, Kyung-Yong Chwa.
    Casting an Object with a Core.
    In Proc. 16th Annual International Symposium on Algorithms and Computation (ISAAC 2005), LNCS 3827, pages 882-891, 2005
  27. Hee-Kap Ahn, Otfried Cheong.
    Stacking and Bundling two Convex Polygons.
    In Proc. 16th Annual International Symposium on Algorithms and Computation (ISAAC 2005), LNCS 3827, pages 40-49, 2005
  28. Hee-Kap Ahn, Otfried Cheong, Chong-Dae Park, Chan-Su Shin, Antoine Vigneron.
    Maximizing the Overlap of Two Planar Convex Sets under Rigid Motions.
    In Proc. 21st Annu. ACM Symposium on Computational Geometry (SoCG 2005), pages 356-363, 2005
  29. Hee-Kap Ahn, Peter Brass, Otfried Cheong, Hyeon-Suk Na, Chan-Su Shin, Antoine Vigneron.
    Approximation algorithms for Inscribing or Circumscribing an Axially Symmetric Polygon to a Convex Polygon.
    In Proc. 10th Annual International Computing and Combinatorics Conference (COCOON 2004) LNCS 3106, pages 259-267, 2004
  30. Hyun-Jhin Lee, Jinwook Kim, Hee-Kap Ahn, Sang Chul Ahn, Ik Jae Kim, Hyoung-Gon Kim, Heedong Ko.
    VR Experience Design in Tangible Space : Heritage Alive!
    In Proc. 15th Triennial Congress of International Ergonomics Association (IEA 2003) and 7th Joint Conference of the Ergonomics Society of Korea and the Japan Ergonomics Society, 2003
  31. Jinwook Kim, Hee-Kap Ahn, Heedong Ko.
    Description and Response Generation of Cyberspace.
    In Proc. Proc. 15th Triennial Congress of International Ergonomics Association (IEA 2003) and 7th Joint Conference of the Ergonomics Society of Korea and the Japan Ergonomics Society, 2003
  32. ChangHoon Park, HeeDong Ko, Changseok Cho, Hee-Kap Ahn, Yo-Sub Han, TaiYun Kim.
    NAVER: Design and Implementation of Networked Virtual Environments Based on PC Cluster.
    In Proc. 6th Joint Conference of the Ergonomics Society of Korea and the Japan Ergonomics Society, pages 221-228, 2002
  33. Jaeho Chang, Heedong Ko, Heekap Ahn, Changhoon Park.
    NAVER Musical Composition Environment.
    In Proc. Virtual Systems and MultiMedia (VSMM 2002), pages 809-814, 2002
  34. ChangHoon Park, HeeDong Ko, Hee-Kap Ahn, Jinwook Kim.
    NAVER: design and implementation of XML-based VR Framework on a PC cluster.
    In Proc. Virtual Systems and MultiMedia (VSMM 2002) pages 967-975, 2002
  35. Hee-Kap Ahn, Otfried Cheong, René van Oostrum.
    Casting a Polyhedron with Directional Uncertainty.
    In Proc. 13th Annual International Symposium on Algorithms and Computation (ISAAC 2002) LNCS 2518, pages 274-285, 2002
  36. Hee-Kap Ahn, Siu-Wing Cheng, Otfried Cheong, Mordecai Golin, René van Oostrum.
    Compatitive Facility Location along a Highway.
    In Proc. 7th Annual International Computing and Combinatorics Conference (COCOON 2001) LNCS 2108, pages 237-246, 2001
  37. Hee-Kap Ahn, Siu-wing Cheng, Otfried Cheong, Jack Snoeyink.
    The Reflex-Free Hull.
    In Proc. 13th Canadian Conference on Computational Geometry (CCCG 2001) pages 9-12, 2001
  38. Hee-Kap Ahn, Otfried Cheong, Jiri Matousek, Antoine Vigneron.
    Reachability by Paths of Bounded Curvature in Convex Polygons.
    In Proc. 16th Annu. ACM Symposium on Computational Geometry (SoCG 2000) pages 251-259, 2000
  39. H.-K. Ahn, P. Bose, J. Czyzowicz, N. Hanusse, E. Kranakis, P. Morin.
    Flipping your Lid.
    In Proc. 12th Canadian Conference on Computational Geometry (CCCG 2000) pages 13-16, 2000
  40. Hee-Kap Ahn, Siu-Wing Cheng, Otfried Cheong.
    Casting with Skewed Ejection Direction Revisited.
    In Proc. 11th Canadian Conference on Computational Geometry (CCCG 1999) pages 128-131, 1999
  41. Hee-Kap Ahn, Siu-Wing Cheng, Otfried Cheong.
    Casting with Skewed Ejection Direction.
    In Proc. 9th Ann. International Symposium on Algorithms and Computation (ISAAC 1998) LNCS 1533, pages 139-148, 1998
  42. Hee-Kap Ahn, Mark de Berg, Prosenjit Bose, Siu-Wing Cheng, Dan Halperin, Jiri Matousek, Otfried Schwarzkopf.
    Separating an Object from its Cast.
    In Proc. 13th Annu. ACM Symposium on Computational Geometry (SoCG 1997) pages 221-230, 1997

Other publications

  1. Hee-Kap Ahn, Siu-Wing Cheng, Hyuk Jun Kweon, Juyoung Yon.
    Overlap of Convex Polytopes under Rigid Motion.
    In Proc. 15th Japan-Korea Joint Workshop on Algorithms and Computation (WAAC 2012), 2012.
  2. Hee-Kap Ahn, Sang Won Bae, Shin-ichi Tanigawa.
    Rectilinear Covering for Imprecise Input Points.
    In Proc. 15th Japan-Korea Joint Workshop on Algorithms and Computation (WAAC 2012), 2012.
  3. Hee-Kap Ahn, Hyo-Sil Kim, Sang-Sub Kim, Wanbin Son.
    Computing Euclidean 2-centers over Streaming Data.
    In Proc. 15th Japan-Korea Joint Workshop on Algorithms and Computation (WAAC 2012), 2012.
  4. Hee-Kap Ahn, Sang-Sub Kim, Christian Knauer, Hyeon-Suk Na, Lena Schlipf, Chan-Su Shin, Antoine Vigneron.
    Covering and Piercing Disks with Two Centers.
    To appear in Proc. 27th European Workshop on Computational Geometry (EuroCG 2011), 2011.
  5. Hee-Kap Ahn, Christian Knauer, Marc Scherfenberg, Lena Schlipf, Antoine Vigneron.
    Computing the Discrete Fréchet Distance with Imprecise Input.
    In Proc. 26th European Workshop on Computational Geometry (EuroCG 2010), pages 13-16, 2010.
  6. Hee-Kap Ahn, Yoshio Okamoto, Iris Reinbacher.
    Tracing a Virus.
    In Proc. 3rd AAAC Annual Meeting, 2010.
  7. Wanbin Son, Hee-Kap Ahn.
    Skyline Queries in Metric Space.
    In Proc. 3rd AAAC Annual Meeting, 2010.
  8. Hee-Kap Ahn, Yoshio Okamoto.
    Adaptive Computational Geometry.
    In RIMS Proceedings of Workshop, pages 114-125, 2009.
  9. Hee-Kap Ahn, Marc Scherfenberg, Lena Schlipf, Antoine Vigneron.
    Computing the Discrete Fréchet Distance with Imprecise Input.
    In Proc. 12th Korea-Japan Joint Workhop on Algorithms and Computation (WAAC 2009), pages 132-137, 2009.
  10. Hee-Kap Ahn, Yoshio Okamoto.
    An Adaptive Algorithm for the Planar Convex Hull.
    In Proc. 2nd AAAC Annual Meeting, 2009.
  11. Hee-Kap Ahn, Sang Won Bae, Sang-Sub Kim, Matias Korman, Iris Reinbacher, Wanbin Son.
    Square and Rectangle Covering with Outliers.
    In Proc. 25th European Workshop on Computational Geometry, pages 273-276, 2009.
  12. Hee-Kap Ahn, Yoshio Okamoto.
    Adaptive Computational Geometry.
    In Proc. Workshop on Computational Geometry and Discrete Mathematics, Gyoto, Japan, pages 51-54, 2008
  13. Hee-Kap Ahn, Siu-Wing Cheng, Iris Reinbacher.
    Maximum Overlap of Convex Polytopes under Translation.
    In Proc. 11th Japan-Korea Joint Workshop on Algorithms and Computation, pages 181-188, 2008.
  14. Sang Won Bae, Hee-Kap Ahn.
    Optimal Disjoint Two-box Covering of Points.
    In Proc. 1st AAAC Annual Meeting, 2008.
  15. Hee-Kap Ahn, Siu-Wing Cheng, Iris Reinbacher.
    Translation Algorithms for Overlaying Convex Polyhedra.
    In Proc. 1st AAAC Annual Meeting, 2008
  16. Sang Won Bae, Chunseok Lee, Hee-Kap Ahn, Sunghee Choi, Kyung-Yong Chwa.
    Maintaining Extremal Points and Its Applications to Deciding Optimal Orientations.
    In Proc. 10th Korea-Japan Joint Workshop on Algorithms and Computation, pages 64-71, 2007.
  17. Hee-Kap Ahn, Mark de Berg, Otfried Cheong, Herman Haverkort, Frank van der Stappen, Laura Toma.
    River Networks and Watershed Maps of Triangulated Terrains Revisited.
    In Proc. 22nd European Workshop on Computational Geometry (EWCG 2006), pages 173-176, 2006
  18. Hee-Kap Ahn, Sang Won Bae, Otfried Cheong.
    A New Geometric Proof on Shortest Paths with Bounded Curvature.
    In Proc. 32nd KISS fall conference, pages 958-960, 2005
  19. Chong-Dae Park, Chan-Su Shin, Hee-Kap Ahn, Otfried Cheong, Antoine Vigneron.
    Approximation algorithms for maximizing the overlap of two planar convex sets under rigid motions.
    In Proc. Korea Computer Congress 2005, pages 901-903, 2005
  20. Hyeon-Suk Na, Chan-Su Shin, Hee-Kap Ahn.
    Geometric properties of roofs of rectilinear polygons.
    In Proc. Korea Computer Congress 2005, pages 895-897, 2005
  21. Hee-Kap Ahn, Yo-Sub Han, Chan-Su Shin.
    Approximating a Minimum-Diameter Spanning Tree with Bounded Degree.
    In Proc. Japan Conference on Discrete and Computational Geometry (JCDCG 2004)
  22. Yong Hee Park, Sang Won Bae, Hee-Kap Ahn, Kyung-Yong Chwa.
    Casting an Object with a Core.
    In Proc. 31st KISS fall conference, pages 706-708, 2004
  23. Chong-Dae Park, Chan-Su Shin, Hee-Kap Ahn, Hyunsub Lee, Kyung-Yong Chwa, Otfried Cheong.
    Approximating the Largest Empty and Fat Rectangle.
    In Proc. 31st KISS spring conference, pages 718-720, 2004
  24. Hee-Kap Ahn, Yo-Sub Han, Chan-Su Shin.
    Minimum Diameter Spanning Tree with Bounded Degree.
    In Proc. 30th KISS spring conference pages 806-808, 2003.
  25. Heedong Ko, Hee-Kap Ahn, Jin-Wook Kim, Jong-Guk Kim, Jae-Bok Song, Hong-Jun Eu, Myung-Whan Yun, In-Su Woo, Yeon-Dong Park.
    Evaluation of Car Prototype using CAVE-like Systems.
    In Proc. 30th KSES spring conference pages 66-73, 2002.
  26. Hee-Kap Ahn.
    Geometric Aspects of the Casting Process.
    Ph.D. Thesis, ISBN 90-393-2869-2, Utrecht University.
  27. Hee-Kap Ahn, Nikos Mamoulis, Ho Min Wong.
    A Survey on Multidimensional Access Methods.
    Tech.Report, UU-CS-2001-14, May 2001, Institute of Information and Computing Sciences, Utrecht University
  28. Hee-Kap Ahn, Otfried Cheong, Chan-Su Shin.
    Bridging Convex Regions and Related Problems.
    In Proc. 17th European Workshop on Computational Geometry (CG 2001) pages 53-56, 2001.
    Invited to Computational Geometry: Theory and Applications
  29. Hee-Kap Ahn, Siu-Wing Cheng, Otfried Cheong.
    Casting with Skewed Ejection Direction (extended abstract).
    In Proc. First ACM HongKong Postgraduate Research Day (1998)
  30. Hee-Kap Ahn.
    Casting with two-part cast: Opposite and Non-opposite cast removal.
    Master Thesis, POSTECH.
  31. Hee-Kap Ahn, Otfried Schwarzkopf.
    Castable Polyhedra in General Setting.
    In Proc. 24th KISS spring conference pages 703-706, 1997.