From al001 at mail1.rrz.Uni-Koeln.DE Fri Jun 18 09:32:36 1999 From: al001 at mail1.rrz.Uni-Koeln.DE (Irwin Scollar) Date: Mon Jan 9 13:40:57 2006 Subject: Points_in_Plane_Triangles Message-ID: <199906180632.IAA06529@campfire.rrz.Uni-Koeln.DE> Given a large scatter of points bounded by a convex hull on a plane, find three points in the scatter which are the vertices of a triangle which has an area larger than that defined by any other set of three points. Can anyone supply a reference to an efficient algorithm and a data structure for solving this problem faster than by brute force or suggest a method for dealing with it if nothing has been published? Irwin Scollar Cologne University AL001@MAIL1.RRZ.UNI-KOELN.DE ------------- 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://uiuc.edu/~sariel/CG/compgeom/threads.html. From flores at siam.org Wed Jun 16 14:01:20 1999 From: flores at siam.org (flores@siam.org) Date: Mon Jan 9 13:40:57 2006 Subject: PLEASE POST IN YOUR ELECTRONIC NEWSLETTER. THANK YOU. Message-ID: <9906169295.AA929552481@venn.siam.org> Sixth SIAM Conference on Geometric Design and Short Course on Applications of Classical Geometry in Computer-Aided Design November 2-6, 1999 Sheraton Old Town Hotel Albuquerque, New Mexico The technical program and information on hotel, transportation, and registrations for both conference and short course are now available on the Web. Please visit the conference Web page at www.siam.org/meetings/gd99/ or contact SIAM at meetings@siam.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://uiuc.edu/~sariel/CG/compgeom/threads.html. From hoffmann at lala.inf.ethz.ch Fri Jun 18 16:58:06 1999 From: hoffmann at lala.inf.ethz.ch (Michael Hoffmann) Date: Mon Jan 9 13:40:57 2006 Subject: Points_in_Plane_Triangles In-Reply-To: al001@mail1.rrz.Uni-Koeln.DE (Irwin Scollar) "Points_in_Plane_Triangles" (Jun 18, 8:32am) References: <199906180632.IAA06529@campfire.rrz.Uni-Koeln.DE> Message-ID: <9906181558.ZM24307@lala.inf.ethz.ch> On Jun 18, 8:32am, Irwin Scollar wrote: > Subject: Points_in_Plane_Triangles > Given a large scatter of points bounded by a convex hull on a plane, find > three points in the scatter which are the vertices of a triangle which has an > area larger than that defined by any other set of three points. If you are looking for an implementation, we have implemented a O(kn + n log n) algorithm for finding the maximal (wrt area or perimeter) k-gon in the CGAL library, see http://www.cs.uu.nl/CGAL The implementation is based on an algorithm by Aggarwal et al, references below. For the special case of maximum area triangles there is also a linear algorithm by Dobkin and Snyder (not (yet;) in CGAL). Best regards, Michael Hoffmann Theoretical Computer Science email: hoffmann@inf.ethz.ch ETH Zentrum, IFW B46.2 phone: +41-1-6327390 CH-8092 Zurich, Switzerland fax: +41-1-6321172 @inproceedings{ds-gmmmc-79 , author = "D. P. Dobkin and L. Snyder" , title = "On a general method for maximizing and minimizing among certain geometric problems" , booktitle = "Proc. 20th Annu. IEEE Sympos. Found. Comput. Sci." , year = 1979 , pages = "9--17" } @article{akmsw-gamsa-87 , author = "A. Aggarwal and M. M. Klawe and S. Moran and P. W. Shor and R. Wilber" , title = "Geometric applications of a matrix-searching algorithm" , journal = "Algorithmica" , volume = 2 , year = 1987 , pages = "195--208" , keywords = "polygons, furthest neighbors, convex polygons, routing" , succeeds = "akmsw-gamsa-86" , update = "98.07 agarwal, 96.09 agarwal, 96.05 agarwal, 95.05 korneenko" } ------------- 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://uiuc.edu/~sariel/CG/compgeom/threads.html. From dls at eecs.tufts.edu Tue Jun 22 12:09:51 1999 From: dls at eecs.tufts.edu (Diane Souvaine) Date: Mon Jan 9 13:40:57 2006 Subject: Visiting Position at Tufts University for 1999-2000 Message-ID: <199906221509.LAA23257@allegro.eecs.tufts.edu> TUFTS UNIVERSITY - The Electrical Engineering and Computer Science Department invites applications for a new visiting position in computer science for 1999-2000, created in response to the unexpected resignation of an associate professor to accept a job in industry. We expect to conduct a full search during 1999-2000 for a tenure-track position to begin in fall 2000. Applicants should have a strong commitment both to research and to teaching. All research areas will be considered. Submit a curriculum vitae and names, email addresses, and telephone numbers of at least three references, two of whom can talk about your teaching. Review of applications will begin immediately and will continue until the position is full. Please address application materials to Prof. Robert Gonsalves, Chair, Electrical Engineering and Computer Science Department, Tufts University 161 College Avenue Medford, MA 02155 FAX: 617-627-3220 VOICE: 617-627-3217 EMAIL: bobg@eecs.tufts.edu Information about the department can be found at http://www.eecs.tufts.edu Please feel free to contact me with questions. Diane Souvaine, 617-627-2486, dls@eecs.tufts.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://uiuc.edu/~sariel/CG/compgeom/threads.html. From jsbm at ams.sunysb.edu Tue Jun 22 13:57:45 1999 From: jsbm at ams.sunysb.edu (Joseph Mitchell) Date: Mon Jan 9 13:40:57 2006 Subject: postdoc/visitor opportunity at Stony Brook Message-ID: <199906221658.MAA14609@amirani.ams.sunysb.edu> Postdoctoral/Visiting Position starting Fall, 1999 Computational Geometry Lab University at Stony Brook We anticipate having a postdoctoral or visiting position available at the University at Stony Brook, in the Department of Applied Mathematics and Statistics, starting in the fall of 1999. Duties would include: 1. Conducting research, in collaboration with Stony Brook faculty and students, in support of various projects in the areas of computational geometry and algorithms, with applications in computer graphics, visualization, manufacturing, and GIS. Many of the applications projects require facility with geometric software and algorithm development. 2. Assisting in the supervision of graduate students in the Lab. 3. Modest teaching (one course per semester). Faculty in the algorithms/geometry area include Estie Arkin, Joe Mitchell, Michael Bender, Steve Skiena, Amitabh Varshney, and adjuncts Martin Held, Claudio Silva, Karel Zikan. In addition, there are opportunities to collaborate with the Center for Visual Computing (Ari Kaufman, director) at Stony Brook. To be considered for the position, send a notice of intent, and a vita (in ascii, latex, or ps) to Joe Mitchell (jsbm@ams.sunysb.edu), by July 15, 1999. The University at Stony Brook is an Equal Opportunity employer. ------------- 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://uiuc.edu/~sariel/CG/compgeom/threads.html. From wads at scs.carleton.ca Thu Jun 24 19:51:33 1999 From: wads at scs.carleton.ca (WADS'99) Date: Mon Jan 9 13:40:57 2006 Subject: 1999 Workshop on Algorithms And Data Structures Message-ID: 1999 Workshop on Algorithms And Data Structures (WADS'99) August 11 - August 14, 1999 Harbour Center, Simon Fraser University, Vancouver, BC, Canada Sponsored by The Pacific Institute for Mathematical Sciences. Organizing Comm.: B. Bhattacharya, A. Gupta, A. Liestman, T. Shermer e-mail: wads@cs.sfu.ca Conference Information: http://www.pims.math.ca/sections/activities/wads99.html Conference Program: http://www.pims.math.ca/wads99/programme.html Registration: http://www.pims.math.ca/wads99/register.html REGISTER NOW! EARLY REGISTRATION DEADLINE: July 9 ------------- 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://uiuc.edu/~sariel/CG/compgeom/threads.html. From gaertner at inf.ethz.ch Fri Jun 25 14:33:53 1999 From: gaertner at inf.ethz.ch (Bernd Gaertner) Date: Mon Jan 9 13:40:57 2006 Subject: Late Summer School at ETH Zuerich Message-ID: <199906251133.NAA22078@blabla.inf.ethz.ch> Late Summer School ``Facets of the Polytope World'' ETH Zuerich, Switzerland, September 13-16, 1999 The goal of this school is to introduce a number of basic concepts in discrete geometry to students of different levels by means of lectures and exercises. Each of the three speakers will cover a full day (titles and abstracts below), and one more day (Wednesday 12) is reserved for a hike in the beautiful mountains of Switzerland. There will be no assumptions beyond basic Linear Algebra and a familiarity with mathematical concepts in general. There is no participation fee. We arrange for student housing in single or double rooms, expecting arrival Sunday night and departure Friday morning. The rates are CHF 80,- (single) resp. CHF 60,- (double) for the whole period. We provide a certificate of participation (with an exam, if that is requested). The school will be announced as a regular course with credit at the ETH. The number of participants is limited. An application should be sent as early as possible, but definitely before July 15 to the address below. It should include a short Curriculum Vitae and indication whether accommodation as offered above is needed (in which case early registration is highly recommended). Bernd Gaertner Departement Informatik, ETH Zentrum, IFW CH-8092 Zuerich, Switzerland For further information: Tel ++41 1 632 73 92, Fax ++41 1 632 11 72, email gaertner@inf.ethz.ch, or richter@inf.ethz.ch ____________________ -------------------- Speakers and topics: --------------------------------------------------------------------------- Bernd Gaertner: ``Randomization and Abstraction in geometric optimization'' Many popular geometric optimization problems (smallest enclosing ball of points, distance between polytopes,...) can be regarded as instances of a simple abstract class known as `LP-type problems'. I will introduce this general framework, describe randomized algorithms for solving all problems in the class, and derive bounds for their expected performance. Among other upper and lower bounds, I will review the currently best theoretical bound for solving the special geometric optimization problem of linear programming in the unit cost model. --------------------------------------------------------------------------- Juergen Richter-Gebert: ``Polytopes in small dimensions'' Already in dimensions three and four, polytopes show a large variety of interesting properties, surprising effects and widely open research problems. We will try to explore some of the most interesting parts of these stories. Among them are - the relation of Spiderwebs, a photograph of the Golden Gate Bridge and polytopes, - how one can cage eggs and potatoes in a tight way by three dimensional polytopes, - why four dimensional polytopes behave as bad as arbitrary polynomials, - and how difficult it is to embed a polytope in a finite quantitized universe --------------------------------------------------------------------------- Emo Welzl: ``Halving Point Sets -- The Inner Structure of Point Sets'' The convex hull of a point set gives a convex polytope, which -- in some sense -- describes the outer structure of the point set. Here we plan to investigate the inner structure, along questions like: Given 2n points in the plane, no three on a line. How many pairs of points can be connected by a halving line, i.e., a line halving the remaining 2n-2 points? So for four points, there are at most three such pairs? Even this innocent looking question in the plane is far from being solved (the answer is known for up to 12 points), not to mention the higher dimensional counterparts. We demonstrate several techniques from discrete geometry applied to these questions, we point out sometimes surprising connections to other problems, and we exhibit a number of computational problems, where these questions arise. ------------- 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://uiuc.edu/~sariel/CG/compgeom/threads.html. From jsbm at ams.sunysb.edu Fri Jun 25 02:13:33 1999 From: jsbm at ams.sunysb.edu (Joseph Mitchell) Date: Mon Jan 9 13:40:57 2006 Subject: Steering Committee Message-ID: <199906250513.BAA28082@amirani.ams.sunysb.edu> The new steering committee (Pankaj Agarwal, Jean-Daniel Boissonnat, Mike Goodrich, Joe Mitchell, and Jack Snoeyink) have assigned officers among themselves, as follows: Chair (99-00): Joe Mitchell (00-01): Mike Goodrich Secretary (99-01): Pankaj Agarwal Please feel free to raise issues, suggestions, concerns with any or all of the committee members ------------- 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://uiuc.edu/~sariel/CG/compgeom/threads.html. From snoeyink at cs.ubc.ca Fri Jun 25 09:50:49 1999 From: snoeyink at cs.ubc.ca (Jack Snoeyink) Date: Mon Jan 9 13:40:57 2006 Subject: 11th Canadian Conference on Computational Geometry, Aug 15-18 Message-ID: <199906251550.IAA19146@pedigree.cs.ubc.ca> -------------------------------------------------------- Eleventh Canadian Conference on Computational Geometry University of British Columbia, Vancouver, Canada August 15-18, 1999 http://www.cs.ubc.ca/conferences/CCCG housing deadline July 15 -------------------------------------------------------- The Eleventh Canadian Conference on Computational Geometry (CCCG '99) will be held at the University of British Columbia, Vancouver, Canada, August 15-18, 1999, immediately following the Workshop on Algorithms and Data Structures (WADS'99) We have a programme of 45 submitted presentations plus invited lectures on geometry, robotics, and molecular modeling by Victor Klee (mathematics, Univ of Washington), Dinesh Pai (computer science, UBC) and Susanne Fortier (chemistry, Queens Univ.) See http://www.cs.ubc.ca/conferences/CCCG Registration fees 100 CN$, or 40 CN$ for students, include proceedings, welcome reception, and salmon barbeque in the UBC Botanical Gardens. Registration will occur on site, although we do ask that you inform us of your plans so that we can prepare badges, receipts, and estimate food. Please use the form on the web, or send an email with your name, affiliation (for badge), and address. Tickets for Bard on the Beach performances may also be requested. Aug 16: Vancouver Symphony Orchestra + the Bard company (25 CN$) Aug 18: (23.50 CN$) Midsummer Night's Dream (18 CN$) Measure for Measure We hope that you will join us. o Jack _/\_. snoeyink@cs.ubc.ca (')>-(`) http://www.cs.ubc.ca/spider/snoeyink/ ------------ CCCG focuses on the mathematics of discrete geometry from a computational point of view. Abstracting and studying the geometry problems that underly important applications of computing (such as geographic information systems, computer-aided design, simulation, robotics, solid modeling, databases, and graphics) leads not only to new mathematical results, but also to improvements in these applications. Despite its international following, CCCG maintains the informality of a smaller workshop and attracts a large number of students. (Low registration fees and possibility of dorm accomodations also help.) ------------- 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://uiuc.edu/~sariel/CG/compgeom/threads.html.