From martin at farach-colton.com Wed Jul 3 10:18:21 2002 From: martin at farach-colton.com (Martin Farach-Colton) Date: Mon Jan 9 13:41:06 2006 Subject: Reminder: SODA Deadline July 9th Message-ID: <7E1220C5-8EA0-11D6-B3BD-00039388DD2E@farach-colton.com> See CFP @ http://www.siam.org/meetings/da03/ See http://cmt.research.microsoft.com/SODA03/ for submission procedure. ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From aupetit at dase.bruyeres.cea.fr Mon Jul 1 12:41:35 2002 From: aupetit at dase.bruyeres.cea.fr (aupetit) Date: Mon Jan 9 13:41:06 2006 Subject: Nearest Neighbor searching with Delaunay... Message-ID: <200207010941.LAA26371@tupai.bruyeres.cea.fr> Hello, Locating the nearest neighbor (NN) of a query point in a finite set of n reference points is in O(n). But if we construct the Delaunay triangulation of the reference points, then it should be easier to find the NN of any query point by marching along the graph structure from a current reference point to its neighbor which is the closest to the query, considering this as the new current reference, and iterating until no neighbors are closer to the query than the current reference (i.e. steepest descent onto the graph considering the distance between the current reference and the query). Is there any paper using this approach or theorem proving that using such steepest descent on the Delaunay triangulation leads to a unique global optimum? Thank you for your help. Michael Aupetit ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From lhf at visgraf.impa.br Wed Jul 3 13:37:58 2002 From: lhf at visgraf.impa.br (Luiz Henrique de Figueiredo) Date: Mon Jan 9 13:41:07 2006 Subject: IV Brazilian Symposium on GeoInformatics - Call for Papers Message-ID: <200207031537.g63Fbwm05767@Newton.visgraf.impa.br> ------------------------------------------------------------------------ IV Brazilian Symposium on GeoInformatics - GeoInfo 2002 December 5-6 2002 - Hotel Gloria - Caxambu - Minas Gerais - Brazil ------------------------------------------------------------------------ (Apologies for cross-postings) PRELIMINARY CALL FOR PAPERS GeoInfo 2002 is an annual forum for exploring ongoing research, development and innovative applications on geographic information science and related areas, including, but not limited to, the following fields: * Spatial databases * Spatial and spatio-temporal data modeling * Interoperability and standards in GIS * Ontologies for spatial data * Spatial metadata * Spatial, spatio-temporal, and multidimensional access methods * Spatial queries processing and optimization * Multiple representations in spatial databases * Intrgrity constraints in spatio-temporal databases * Geospatial versioning * Graphical aspects of GIS and spatial databases * Vector and raster data management issues * Computational geometry * Virtual reality and 3D GIS * Large volume GIS servers and parallel GIS * Visual query languages * Similarity search * GIS and Internet * Location-based services * Mobile and distributed geographic information services * Real-time spatio-temporal GIS * Spatial data warehouses and decision support systems * Spatial and spatio-temporal data mining, knowledge discovery * Spatial data quality * Content-based image retrieval * Geostatistics * Spatial analysis and spatial statistics * Innovative applications of geotechnologies Papers should describe original research, ongoing (preferably) or recently completed. Papers can be submitted in Portuguese, English or Spanish, and are limited to 8 pages. Complete instructions and further information are available at http://www.pbh.gov.br/prodabel/cde/geoinfo2002. IMPORTANT DATES August 30, 2002 - Paper submission September 30, 2002 - Notification of acceptance October 15, 2002 - Camera-ready version December 5-6, 2002 - GeoInfo 2002 at Caxambu, Minas Gerais, Brazil PROGRAM COMMITTEE Clodoveu Davis (PRODABEL) (coordinator) Karla Albuquerque de Vasconcelos Borges (PRODABEL) (coordinator) Alberto Laender (UFMG) Ana Carolina Salgado (UFPE) Antônio Miguel Monteiro (INPE) Arnaldo de Albuquerque Araújo (UFMG) Cirano Iochpe (UFRGS) Cláudia Bauzer Medeiros (UNICAMP) Frederico Fonseca (Penn State) Gilberto Câmara (INPE) Jansle Vieira Rocha (UNICAMP) José Luiz de Souza Pio (FUA) João Argemiro Paiva (INPE) Jugurta Lisboa Filho (UFV) Luiz Henrique de Figueiredo (IMPA) Max Egenhofer (University of Maine) Valeria Times (UFPE) (other names to be confirmed) EXECUTIVE COMMITTEE Antonio Miguel Monteiro (INPE) Clodoveu Davis (PRODABEL) Gilberto Camara (INPE) Maria da Piedade Oliveira (PRODABEL) ------------------------------------------------------------------------ ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From mast at sbox.tugraz.at Tue Jul 9 11:05:23 2002 From: mast at sbox.tugraz.at (Martin Stettner) Date: Mon Jan 9 13:41:07 2006 Subject: Nearest Neighbor searching with Delaunay... In-Reply-To: <200207010941.LAA26371@tupai.bruyeres.cea.fr> Message-ID: <000701c2271f$62cb1120$014ba8c0@martin> Hi, I'm not sure if I understand your intentions but I think that your approach would not be useful: By building the Delaunay triangulation of a point set you can easily obtain a point location structure which allows to locate a new point in O(lg n) time. cf. Mark de Berg et al. Computational Geometry - Algorithms an Applications p. 194f kind regards Martin Stettner Micahel Aupetit wrote > > Hello, > > Locating the nearest neighbor (NN) of a > query point in a finite set of n reference points > is in O(n). But if we construct the Delaunay > triangulation of the reference points, then it > should be easier to find the NN of any query > point by marching along the graph structure from > a current reference point to its neighbor which is the > closest to the query, considering this as the new > current reference, and iterating until no neighbors are > closer to the query than the current reference > (i.e. steepest descent onto the graph considering the > distance between the current reference and the query). > > Is there any paper using this approach or theorem > proving that using such steepest descent on the > Delaunay triangulation leads to a unique global optimum? > > Thank you for your help. > > Michael Aupetit > > ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From jrs at buffy.EECS.Berkeley.EDU Sun Jul 7 22:42:17 2002 From: jrs at buffy.EECS.Berkeley.EDU (Jonathan Shewchuk) Date: Mon Jan 9 13:41:07 2006 Subject: Nearest Neighbor searching with Delaunay... In-Reply-To: Your message of "Mon, 01 Jul 2002 11:41:35 +0200." <200207010941.LAA26371@tupai.bruyeres.cea.fr> Message-ID: <200207080442.VAA16919@buffy.EECS.Berkeley.EDU> Michael Aupetit asks: > Locating the nearest neighbor (NN) of a > query point in a finite set of n reference points > is in O(n). But if we construct the Delaunay > triangulation of the reference points, then it > should be easier to find the NN of any query > point by marching along the graph structure from > a current reference point to its neighbor which is the > closest to the query, considering this as the new > current reference, and iterating until no neighbors are > closer to the query than the current reference > (i.e. steepest descent onto the graph considering the distance > between the current reference and the query). > > Is there any paper using this approach or theorem > proving that using such steepest descent on the > Delaunay triangulation leads to a unique global optimum? I am not aware of such a paper, but there must have been one (if not dozens). Here's a "proof" that you will find a global optimum (though obviously it might not be unique). It's well known that the Delaunay triangulation is isomorphic to the lower convex hull of the "lifted" point set. (Edelsbrunner and Seidel, Discrete & Computational Geometry 1:25-44, 1986.) The "lifting map" maps each vertex v of the d-dimensional DT to a vertex (v, |v|^2) in d+1 dimensions. The downward-facing facets of the d+1 dimensional convex hull of the lifted vertices correspond to the d-simplices of the DT. (I have a picture of a lifting map at the bottom of http://www.cs.berkeley.edu/~jrs/stab.html if you want to get a clearer idea.) So the procedure you describe is the simplex algorithm for linear programming. For instance, take your DT, translate it so the query point is at the origin, and apply the lifting map to the translated vertices. Note that the height to which each vertex is lifted, |v|^2, is its distance from the query point. The goal is to find the lowest lifted vertex (i.e. the one lifted to the least height) of the convex hull, which is a linear programming problem. Jonathan Shewchuk ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From johnh at wv.mentorg.com Wed Jul 10 18:51:11 2002 From: johnh at wv.mentorg.com (John Hershberger) Date: Mon Jan 9 13:41:07 2006 Subject: Nearest Neighbor searching with Delaunay... In-Reply-To: <200207080442.VAA16919@buffy.EECS.Berkeley.EDU> Message-ID: Michael Aupetit asks: > Locating the nearest neighbor (NN) of a > query point in a finite set of n reference points > is in O(n). But if we construct the Delaunay > triangulation of the reference points, then it > should be easier to find the NN of any query > point by marching along the graph structure from > a current reference point to its neighbor which is the > closest to the query, considering this as the new > current reference, and iterating until no neighbors are > closer to the query than the current reference > (i.e. steepest descent onto the graph considering the distance > between the current reference and the query). > > Is there any paper using this approach or theorem > proving that using such steepest descent on the > Delaunay triangulation leads to a unique global optimum? Jonathan Shewchuk replies: > I am not aware of such a paper, but there must have been one (if not dozens). > Here's a "proof" that you will find a global optimum (though obviously it > might not be unique). ....and then goes on to give a nice argument that the search procedure is really the simplex algorithm on the convex hull of lifted points. The idea of searching for nearest neighbors using the Delaunay triangulation was used by Dickerson and Drysdale. I've appended relevant Geombib citations below. --John Hershberger @article{dd-frnns-90 , author = "M. T. Dickerson and R. S. Drysdale" , title = "Fixed-radius near neighbor search algorithms for points and segments" , journal = "Inform. Process. Lett." , volume = 35 , year = 1990 , pages = "269--273" , keywords = "near neighbor search, Delaunay triangulation" , update = "93.09 drysdale" } @inproceedings{dd-ekdnp-91 , author = "M. T. Dickerson and R. L. Drysdale" , title = "Enumerating $k$ distances for $n$ points in the plane" , booktitle = "Proc. 7th Annu. ACM Sympos. Comput. Geom." , year = 1991 , pages = "234--238" , keywords = "Delaunay triangulation, proximity, enumeration" , precedes = "dds-saeid-92" , cites = "aass-sdp-90, bfprt-tbs-73, c-ntcos-85, dd-frnns-90, s-mmdpsl-90t, sh-cpp-75, y-cmstk-82, ZZZ" , update = "97.11 bibrelex, 93.09 drysdale" } @article{dds-saeid-92 , author = "M. T. Dickerson and R. L. Drysdale and J. R. Sack" , title = "Simple algorithms for enumerating interpoint distances and finding $k$ nearest neighbors" , journal = "Internat. J. Comput. Geom. Appl." , volume = 2 , number = 3 , year = 1992 , pages = "221--239" , keywords = "enumeration, selection, Delaunay triangulation, nearest neighbors" , succeeds = "dd-ekdnp-91" , update = "94.01 smid" } ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From lewis at bway.net Thu Jul 11 15:12:55 2002 From: lewis at bway.net (Robert H. Lewis) Date: Mon Jan 9 13:41:07 2006 Subject: Fermat point in three-space In-Reply-To: Message-ID: Hello, The Fermat point of a triangle ABC is the point, say P, that minimizes the sum of the distances d(z,A) + d(z,B) + d(z,C) where z is any point in the plane. There was a good article on this in a recent (May, I think) issue of the American Mathematical Monthly. If all the angles in ABC are less than 120 degrees, P is inside ABC. Otherwise it's one of the vertices. I couldn't find there any reference to the generalization to 3-space. It seems there are two generalizations: Given a tetrahedron ABCD, (1) find the point that minimizes the sum d(z,A) + d(z,B) + d(z,C) + d(z,D). (2) find the point that minimizes the sum of the areas of the triangles formed by z and the six edges of ABCD (assume z is inside ABCD). Searching the web, I found only a comment (no proof) that soap films assume the minimizing form on a wire frame tetrahedron. That would be problem (2). Any information on this problem would be of interest. Robert H. Lewis Mathematics Fordham University Bronx NY rlewis@fordham.edu ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From shlomo.anglister at intel.com Sun Jul 14 09:34:23 2002 From: shlomo.anglister at intel.com (Anglister, Shlomo) Date: Mon Jan 9 13:41:07 2006 Subject: Fermat point in three-space Message-ID: <7C0E66E1B97BD5119B120002A50A63D202BFC345@hasmsx101.iil.intel.com> Hi, What you refer to as a Fermat point in space, can be called a "Steiner point in space". There is an abundance of data in this area. Soap bubbles is an old one, Bell used it many years ago to connect US major cities. Shlomo -----Original Message----- From: Robert H. Lewis [mailto:lewis@bway.net] Sent: Thursday, July 11, 2002 9:13 PM To: compgeom-discuss@research.bell-labs.com Subject: Fermat point in three-space Hello, The Fermat point of a triangle ABC is the point, say P, that minimizes the sum of the distances d(z,A) + d(z,B) + d(z,C) where z is any point in the plane. There was a good article on this in a recent (May, I think) issue of the American Mathematical Monthly. If all the angles in ABC are less than 120 degrees, P is inside ABC. Otherwise it's one of the vertices. I couldn't find there any reference to the generalization to 3-space. It seems there are two generalizations: Given a tetrahedron ABCD, (1) find the point that minimizes the sum d(z,A) + d(z,B) + d(z,C) + d(z,D). (2) find the point that minimizes the sum of the areas of the triangles formed by z and the six edges of ABCD (assume z is inside ABCD). Searching the web, I found only a comment (no proof) that soap films assume the minimizing form on a wire frame tetrahedron. That would be problem (2). Any information on this problem would be of interest. Robert H. Lewis Mathematics Fordham University Bronx NY rlewis@fordham.edu ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From pankaj at cs.duke.edu Wed Jul 17 09:51:32 2002 From: pankaj at cs.duke.edu (Pankaj Kumar Agarwal) Date: Mon Jan 9 13:41:07 2006 Subject: DIMACS Workshop: Modeling Motion Message-ID: <200207171251.IAA23213@kant.cs.duke.edu> ============================================================================= ******************************************************************** * DIMACS * * Center for Discrete Mathematics and Theoretical Computer Science * * Founded as a National Science and Technology Center * ******************************************************************** DIMACS Workshop on Algorithmic Issues in Modeling Motion Date: November 18 - 20, 2002 Location: DIMACS Center, Rutgers University, Piscataway NJ, 08854-8018 Organizers: Pankaj K. Agarwal, Duke University, pankaj@cs.duke.edu Leonidas J. Guibas, Stanford University, guibas@cs.stanford.edu Presented under the auspices of the DIMACS Special Focus on Computational Geometry and Applications. Rationale: Motion, like shape, is one of the fundamental modalities to be modeled in order to represent and manipulate the physical world in a computer. As such, motion representations and the algorithms that operate on them are central to all computational disciplines dealing with physical objects: computer graphics, computer vision, robotics, etc. Modeling motion is also crucial for other disciplines dealing with temporally varying data, including mobile networks, temporal data bases, etc. Motion algorithms require computational resources, and frequently sensing and communication resources as well, in order to accomplish their task. Despite the prominent position that motion plays in so many computer disciplines, little has been done to date to provide a clean conceptual framework for representing motion, describing algorithms on moving objects, and analyzing their behavior and performance. Scope and Format: This workshop aims to bring together people from the different research communities interested in algorithmic issues related to moving objects. The workshop will address core algorithmic issues as well as aspects of modeling and analyzing motion. The goal is to debate and discuss the issues in representing, processing, reasoning, analyzing, searching, and visualizing moving objects; to identify key research issues that need to be addressed, and to help establish relationships which can be used to strengthen and foster collaboration across the different areas. Call for Participation: Authors are invited to submit abstracts for talks to be given at the workshop. Please send the organizers an abstract (up to 2 pages) and a draft of a paper (if you have one). (Since there are no formal proceedings for the workshop, submission of material that is to be submitted to (or to appear in) a refereed conference is allowed and encouraged.) Submissions will be due October 15, 2002. Notification of acceptance: October 31, 2002. Invited Speakers: Mark de Berg, Utrecht University David Mount, University of Maryland Dinesh Pai, University of British Columbia Ileana Streinu, Smith College Carlo Tomasi, Duke University Feng Zhao, Xerox Corporation Registration: (Pre-registration date: November 11, 2002) Regular rate Preregister before deadline $120/day After preregistration deadline $140/day Reduced Rate* Preregister before deadline $60/day After preregistration deadline $70/day Postdocs Preregister before deadline $10/day After preregistration deadline $15/day DIMACS Postdocs $0 Non-Local Graduate & Undergraduate students Preregister before deadline $5/day After preregistration deadline $10/day Local Graduate & Undergraduate students $0 (Rutgers & Princeton) DIMACS partner institution employees** $0 DIMACS long-term visitors*** $0 Registration fee to be collected on site, cash, check, VISA/Mastercard accepted. Our funding agencies require that we charge a registration fee for the workshop. Registration fees cover participation in the workshop, all workshop materials, breakfast, lunch, breaks, and any scheduled social events (if applicable). * College/University faculty and employees of non-profit organizations will automatically receive the reduced rate. Other participants may apply for a reduction of fees. They should email their request for the reduced fee to the Workshop Coordinator at workshop@dimacs.rutgers.edu. Include your name, the Institution you work for, your job title and a brief explanation of your situation. All requests for reduced rates must be received before the preregistration deadline. You will promptly be notified as to the decision about it. ** Fees for employees of DIMACS partner institutions are waived. DIMACS partner institutions are: Rutgers University, Princeton University, AT&T Labs - Research, Avaya, Bell Labs, NEC Research Institute and Telcordia Technologies. ***DIMACS long-term visitors who are in residence at DIMACS for two or more weeks inclusive of dates of workshop. Information on participation, registration, accommodations, and travel can be found at: http://dimacs.rutgers.edu/Workshops/Issues/index.html ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From goodrich at ics.uci.edu Mon Jul 22 14:14:33 2002 From: goodrich at ics.uci.edu (Michael T. Goodrich) Date: Mon Jan 9 13:41:07 2006 Subject: Reminder: Graph Drawing 2002 -- Call for Participation In-Reply-To: <200206281110.aa04451@gremlin-relay.ics.uci.edu> Message-ID: This is a brief reminder that the deadline for early registration for Graph Drawing 2002 is July 31, 2002. > > 10th Annual Conference on Graph Drawing > Graph Drawing 2002 > > Irvine, California > August 26-28, 2002 > > http://www.ics.uci.edu/~gd2002/ > > Call for Pariticipation: The Graph Drawing conference is the primary > forum for papers devoted exclusively to techniques and systems for the > visualization of relational and connectivity information represented > in graphs. > > The deadline for early registration is July 31, 2002. > Registration must be done online (by clicking the appropriate button) > at the conference web site: http://www.ics.uci.edu/~gd2002/ > > Accepted papers: > > A Hybrid Approach for Visualising Large Network Topologies > Siew Cheong Au, Christopher Leckie, Ajeet Parhar and Gerard Wong > > Improving Walker's Algorithm to Run in Linear Time > Christoph Buchheim, Michael Juenger and Sebastian Leipert > > Graph Layout for Workflow Applications with ILOG JViews (System Demonstration) > Gilles Diguglielmo, Eric Durocher, Philippe Kaplan, Georg Sander > > Drawing outer-planar graphs in O(n log n) area > Therese Biedl > > Separating Thickness from Geometric Thickness > David Eppstein > > Book Embeddings and Point-Set Embeddings of Series-Parallel > Emilio Di Giacomo, Walter Didimo and Giuseppe Liotta > > Computing Labeled Orthogonal Drawings > Carla Binucci, Walter Didimo, Giuseppe Liotta and Maddalena > > Orthogonal 3D Shapes of Theta Graphs > Emilio Di Giacomo, Giuseppe Liotta and Maurizio Patrignani > > Sketch-Driven Orthogonal Graph Drawing > Ulrik Brandes, Markus Eiglsperger, Michael Kaufmann and Dorothea Wagner > > Some Applications of Orderly Spanning Trees in Graph Drawing > Ho-Lin Chen, Chien-Chih Liao, Hsueh-I Lu and Hsu-Chun Yen > > Graphs, They are Changing -- Dynamic Graph Drawing for a Sequence of Graphs > Stephan Diehl and Carsten Goerg > > Pathwidth and Three-Dimensional Straight Line Grid Drawings of Graphs > Vida Dujmovi{\'c}, Pat Morin and David R. Wood > > InterViewer: Dynamic Visualization of Protein-Protein Interactions > Kyungsook Han and Byong-Hyon Ju > > Compact Encodings of Planar Orthogonal Drawings > Amrita Chanda and Ashim Garg > > Some Modifications of Sugiyama Approach > Danil E. Baburin > > Semi-Dynamic Orthogonal Drawings of Planar Graphs > Walter Bachl > > Rectangular Drawings of Planar Graphs > Md. Saidur Rahman, Takao Nishizeki and Shubhashis Ghosh > > Extended Rectangular Drawings of Plane Graphs with Designated Corners > Kazuyuki Miura, Ayako Miyazawa and Takao Nishizeki > > Graph Drawing by High-Dimensional Embedding > Yehuda Koren and David Harel > > Layering of Nodes of Arbitrary Size > Falk Schreiber > > HGV: A Library for Hierarchies, Graphs, and Views > Marcus Raitner > > Applying Crossing Reduction Strategies to Layered Compound Graphs > Michael Forster > > Computing and Drawing Isomorphic Subgraphs > S. Bachl and F.J. Brandenburg > > A Framework for Complexity Management in Graph Visualization > U. Dogrusoz and B. Genc > > Advances in C-Planarity Testing of Clustered Graphs > Carsten Gutwenger, Michael J{\"u}nger, Sebastian Leipert, Petra Mutzel, Merijam Percan and Ren{\'e} Weiskircher > > A Branch-and-Cut Approach to the Directed Acyclic Graph Layering Problem > Patrick Healy and Nikola S. Nikolov > > Simple and Efficient Bilayer Cross Counting > W. Barth, M. Juenger and P. Mutzel > > Two New Heuristics for Two-Sided Bipartite Graph Drawings > Matthew Newton, Ondrej Sykora and Imrich Vrto > > Crossing Reduction by Windows Optimization > T. Eschbach, W. Guenther, B. Becker and R. Drechsler > > Drawing Graphs on Two and Three Lines > Sabine Cornelsen, Thomas Schank and Dorothea Wagner > > Fractional Lengths and Crossing Numbers > Ondrej Sykora, Laszlo A. Szekely and Imrich Vrto > > A Partitioned Approach to Protein Interaction Mapping > Yanga Byun, Euna Jeong and Kyungsook Han > > Straight-line Drawings of Binary Trees with Linear Area and Good Aspect Ratio > Ashim Garg and Adrian Rusu > > An Efficient Fixed Parameter Tractable Algorithm for 1-Sided > Vida Dujmovic and Sue Whitesides > > Camera Position Reconstruction and Tight Decision Networks > Ileana Streinu and Elif Tosun > > Geometric graphs with no self-intersecting path of > Janos Pach, Rom Pinchasi and Gabor Tardos > > Drawing Directed Graphs Using One-Dimensional Optimization > Liran Carmel and Yehuda Koren > > A Preprocessor and Two Approximations for the Spring Embedder > P.J. Mutton and P.J. Rodgers > > Geometric Systems of Disjoint Representatives > Jiri Fiala, Jan Kratochvil and Andrzej Proskurowski > > Maintaining the Mental Map for Circular Drawings > Michael Kaufmann and Roland Wiese > > RINGS: A Technique for Visualizing Large Hierarchies > Soon Tee Teoh and Kwan-Liu Ma > > A Group-Theoretic Method for Drawing Graphs Symmetrically > D. Abelson and S.-H. Hong > ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From John.Dickinson at nrc.ca Wed Jul 24 12:29:41 2002 From: John.Dickinson at nrc.ca (Dickinson, John) Date: Mon Jan 9 13:41:07 2006 Subject: Analytic formulas for distance between geometric shapes. Message-ID: <35C5DD9F60FED21192B00004ACA6E6C70245C706@nrclonex1.imti.nrc.ca> I am looking for analytic formulas for distance between basic geometric shapes arbitrarily located and orientated in space. Any references (papers, books) would be greatly appreciated. The Sphere is the easy example as the distance between two spheres in the distance between their centers minus the sum of their radii. On the other hand orientated boxes can't be done analytically but must be done face by face. How about other shapes formed by implicit quadratic equations (eggs, ovaloids, ...) that form not purely symmetric shapes which can be orientated inspace. Do any of these shapes have analytic formulae for distance? John -- -((Insert standard disclaimer here))-|--- Ray's Rule for Precision ---- John Kenneth Dickinson, Ph.D. | "Measure with micrometer; Research Council Officer IMTI-NRC | Mark with chalk; email: john.dickinson@nrc.ca | Cut with axe." ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From zach at cs.uni-bonn.de Thu Jul 25 23:01:05 2002 From: zach at cs.uni-bonn.de (Gabriel Zachmann) Date: Mon Jan 9 13:41:07 2006 Subject: estimate of the volume of a convex body? Message-ID: <20020725220105.A17159@cs.uni-bonn.de> As the subject says, I am looking for an estimate of the volume of a convex body given by A * x <= b where A is an mx3 matrix and b is in R^m. The goal is a *simple* to compute estimation (but not too bad estimate). I am looking for something simpler and more efficient than converting to vertex enumeration. I was thinking of an approximate maximal inscribed ellipsoid, but it seems this is even more complicated ;-) Any ideas, hints, or suggestions will be highly appreciated. Gabriel. -- /---------------------------------------------------------------------\ | Unix is user-friendly -- | | it is just a bit selective about who it makes friends with. | | | | zach@cs.uni-bonn.de __@/' Gabriel.Zachmann@gmx.net | | web.informatik.uni-bonn.de/~zach __@/' www.gabrielzachmann.org | \---------------------------------------------------------------------/ ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From ph+ at cs.cmu.edu Wed Jul 31 01:11:59 2002 From: ph+ at cs.cmu.edu (Paul Heckbert) Date: Mon Jan 9 13:41:07 2006 Subject: Analytic formulas for distance between geometric shapes. References: <35C5DD9F60FED21192B00004ACA6E6C70245C706@nrclonex1.imti.nrc.ca> Message-ID: <020d01c23848$79925870$41e110ac@PHECKBERTDT2> Reference regarding distance from a point to an ellipsoid (requires roots of 6th degree polynomial): @INCOLLECTION{Hart94, AUTHOR={John C. Hart}, TITLE={Distance to an Ellipsoid}, BOOKTITLE={Graphics Gems IV}, EDITOR={Paul Heckbert}, PAGES={113-119}, PUBLISHER={Academic Press}, YEAR={1994}, ADDRESS={Boston}, KEYWORDS={ray tracing, ellipse}, SUMMARY={ Gives the formulas necessary to find the distance from a point to an ellipsoid, or from a point to an ellipse. These formulas can be useful for geometric modeling or for ray tracing. }, } ----- Original Message ----- From: "Dickinson, John" To: "compgeom-discuss@research. bell-labs. com (E-mail)" Sent: Wednesday, July 24, 2002 11:29 AM Subject: Analytic formulas for distance between geometric shapes. > I am looking for analytic formulas for distance between basic geometric > shapes arbitrarily located and orientated in space. Any references (papers, > books) would be greatly appreciated. > > The Sphere is the easy example as the distance between two spheres in the > distance between their centers minus the sum of their radii. On the other > hand orientated boxes can't be done analytically but must be done face by > face. > > How about other shapes formed by implicit quadratic equations (eggs, > ovaloids, ...) that form not purely symmetric shapes which can be orientated > inspace. Do any of these shapes have analytic formulae for distance? > > John > > -- > -((Insert standard disclaimer here))-|--- Ray's Rule for Precision ---- > John Kenneth Dickinson, Ph.D. | "Measure with micrometer; > Research Council Officer IMTI-NRC | Mark with chalk; > email: john.dickinson@nrc.ca | Cut with axe." > > > > ------------- > The compgeom mailing lists: see > http://netlib.bell-labs.com/netlib/compgeom/readme.html > or send mail to compgeom-request@research.bell-labs.com with the line: > send readme > Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. > ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From youngkim at cs.unc.edu Wed Jul 31 14:25:47 2002 From: youngkim at cs.unc.edu (Young J. Kim) Date: Mon Jan 9 13:41:07 2006 Subject: Incremental Penetration Depth Algorithm/Implementation Release Message-ID: Hello folks, We announce the release of an incremental penetration depth algorithm, DEEP (Dual-space Expansion for Estimating Penetration depth). It is now available at: http://gamma.cs.unc.edu/DEEP/ You can also find more info about DEEP from the above web site. Regards, __________________________________________________________________ Young J. Kim http://www.cs.unc.edu/~youngkim GAMMA group, Computer Science TEL: +1-919-962-1761 UNC-Chapel Hill FAX: +1-919-962-1799 __________________________________________________________________ ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. From jch at ad.uiuc.edu Wed Jul 31 11:11:30 2002 From: jch at ad.uiuc.edu (John C Hart) Date: Mon Jan 9 13:41:07 2006 Subject: Analytic formulas for distance between geometric shapes. Message-ID: Here's some more references: This paper has a bunch of distance algorithms for a variety of primitives in its appendix: J.C. Hart. Sphere tracing: A geometric method for the antialiased ray tracing of implicit surfaces. The Visual Computer 12 (10), Dec. 1996, pp. 527-545. Available online at: http://graphics.cs.uiuc.edu/~jch/papers/zeno.ps.gz Some optimizations are also available in: S. Worley, J.C. Hart. Hyper-rendering of hyper-textured surfaces. Proc. of Implicit Surfaces '96 , Oct. 1996, pp. 99-104. http://graphics.cs.uiuc.edu/~jch/papers/hyper.pdf There's also a really nice book I just bought at SIGGRAPH that has a chapter devoted to computing distance functions and finding their stationary points (to find the closest distance from a point to all of the points on a surface). Nicholas M. Patrikalakis & Takashi Maekawa. Shape Interrogation for Computer Aided Design and Manufacturing. Springer, 2002. ISBN: 3540424547. Good luck, -John > -----Original Message----- > From: Paul Heckbert [mailto:ph+@cs.cmu.edu] > Sent: Tuesday, July 30, 2002 11:12 PM > To: Dickinson, John; compgeom-discuss@research. bell-labs. > com (E-mail) > Cc: Hart, John > Subject: Re: Analytic formulas for distance between geometric shapes. > > > Reference regarding distance from a point to an ellipsoid > (requires roots of 6th degree polynomial): > > @INCOLLECTION{Hart94, > AUTHOR={John C. Hart}, > TITLE={Distance to an Ellipsoid}, > BOOKTITLE={Graphics Gems IV}, > EDITOR={Paul Heckbert}, > PAGES={113-119}, > PUBLISHER={Academic Press}, > YEAR={1994}, > ADDRESS={Boston}, > KEYWORDS={ray tracing, ellipse}, > SUMMARY={ > Gives the formulas necessary to find the distance from a > point to an ellipsoid, or from a point to an ellipse. These > formulas can be useful for geometric modeling or for ray tracing. }, } > > ----- Original Message ----- > From: "Dickinson, John" > To: "compgeom-discuss@research. bell-labs. com (E-mail)" > > Sent: Wednesday, July 24, 2002 11:29 AM > Subject: Analytic formulas for distance between geometric shapes. > > > > I am looking for analytic formulas for distance between basic > > geometric shapes arbitrarily located and orientated in space. Any > > references > (papers, > > books) would be greatly appreciated. > > > > The Sphere is the easy example as the distance between two > spheres in > > the distance between their centers minus the sum of their > radii. On > > the other hand orientated boxes can't be done analytically > but must be > > done face by face. > > > > How about other shapes formed by implicit quadratic > equations (eggs, > > ovaloids, ...) that form not purely symmetric shapes which can be > orientated > > inspace. Do any of these shapes have analytic formulae for distance? > > > > John > > > > -- > > -((Insert standard disclaimer here))-|--- Ray's Rule for > Precision ---- > > John Kenneth Dickinson, Ph.D. | "Measure with micrometer; > > Research Council Officer IMTI-NRC | Mark with chalk; > > email: john.dickinson@nrc.ca | Cut with axe." > > > > > > > > ------------- > > The compgeom mailing lists: see > > http://netlib.bell-labs.com/netlib/compgeom/readme.html > > or send mail to compgeom-request@research.bell-labs.com > with the line: > > send readme Now archived at > > http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html. > > > ------------- The compgeom mailing lists: see http://netlib.bell-labs.com/netlib/compgeom/readme.html or send mail to compgeom-request@research.bell-labs.com with the line: send readme Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html.