From knauer at inf.fuberlin.de Mon Aug 5 21:41:58 2002
From: knauer at inf.fuberlin.de (Christian Knauer)
Date: Mon Jan 9 13:41:07 2006
Subject: [DMANET] STACS 2003  2nd Call for papers
MessageID: <15694.50934.362182.396037@gargle.gargle.HOWL>
==============================================================
We apologize for multiple copies of this call for papers
==============================================================
++
 
 STACS 2003 
 
++
20th International Symposium on
Theoretical Aspects of Computer Science
Berlin, Germany
February 27  March 1, 2003
http://www.inf.fuberlin.de/~stacs2003
SCOPE:
Authors are invited to submit papers presenting original and
unpublished research on theoretical aspects of computer
science. Typical areas include (but are not limited to):
* Algorithms and data structures, including: parallel and distributed
algorithms, computational geometry, cryptography, algorithmic
learning theory;
* Automata and formal languages;
* Computational and structural complexity;
* Logic in computer science, including: semantics, specification, and
verification of programs, rewriting and deduction;
* Current challenges, for example: theory, models, and algorithms for
biological computing, quantum computing, mobile and net computing.
SUBMISSIONS:
Authors are invited to submit a draft of a full paper with at most
12 pages, the title page must contain a classification of the topic
covered, preferably using the list of topics above. The paper should
contain a succinct statement of the issues and of their motivation, a
summary of the main results, and a brief explanation of their
significance, accessible to nonspecialist readers. Proofs omitted due
to space constraints must be put into an appendix to be read by the
program committee members at their discretion. Electronic submission
is highly recommended.
In case of problems with access to internet, it is possible to
submit 6 copies of the complete draft and 15 copies of a one page
abstract to the chairperson of the program committee.
Detailed information is available on the web site.
IMPORTANT DATES:
Deadline for submission: September 7, 2002
Notification to authors: November 6, 2002
Final version: December 6, 2002
Symposium: February 27  March 1, 2003
PROCEEDINGS:
Accepted papers will be published in the proceedings of the
Symposium (Lecture Notes in Computer Science, SpringerVerlag).
Simultaneous submission to other conferences with published proceedings
is not allowed.
PROGRAM COMMITTEE:
H. Alt (Free University of Berlin) Chair
A. Bouajjani (LIAFA, Paris)
B. Durand (LIF, Marseille)
P. Fraigniaud (LRI, Orsay)
M. Goldwurm (University of Milan)
M. Grohe (University of Edinburgh)
R. Grossi (University of Pisa)
M. Habib (LIRMM, Montpellier) CoChair
R. Impagliazzo (UC San Diego)
M. Krause (University of Mannheim)
P.B. Miltersen (University of Aarhus)
D. Niwinski (University of Warsaw)
G. Senizergues (LaBRI, Bordeaux)
H.U. Simon (RuhrUniversity of Bochum)
R. Wanka (University of Paderborn)
INVITED SPEAKERS:
Ernst W. Mayr (TU Munich)
Alain Viari (INRIA, Grenoble)
Victor Vianu (UC San Diego)
CONFERENCE CHAIR:
Helmut Alt
Institut f?r Informatik
Freie Universit?t Berlin
Takustra?e 9
D14195 Berlin
Germany
ORGANIZING COMMITTEE CHAIR:
Christian Knauer
EADDRESS:
stacs03@inf.fuberlin.de
WEB SITE:
http://www.inf.fuberlin.de/~stacs2003
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From padmajaveerapaneni at yahoo.com Sun Aug 4 19:22:07 2002
From: padmajaveerapaneni at yahoo.com (padmaja veerapaneni)
Date: Mon Jan 9 13:41:07 2006
Subject: circumcentre
MessageID: <20020805012207.78568.qmail@web20418.mail.yahoo.com>
Hi
Can you please tell me what EXACT is in the code of
Circumcentre of a Tetrahedron .
regards
Padmaja
__________________________________________________
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From funke at mpisb.mpg.de Fri Aug 2 18:35:01 2002
From: funke at mpisb.mpg.de (Stefan Funke)
Date: Mon Jan 9 13:41:07 2006
Subject: ADFOCS 2002  Call for Participation
MessageID: <3D4AA6A5.BD5E0302@mpisb.mpg.de>
(please forward to potentially interested students and postdocs)
* CALL FOR PARTICIPATION *
3nd MaxPlanck Summer School
Advanced Course on the Foundations of Computer Science
ADFOCS 2002
Saarbr?cken, Germany, September 913, 2002
http://www.mpisb.mpg.de/~adfocs
PROGRAM

The program consists of 12 lecture blocks and 8 tutorial/discussion
sessions. The speakers and topics are the following.
 Timothy Chan, University of Waterloo: Random Sampling
 Michele Mosca, University of Waterloo: Quantum Computing
 Prabhakar Raghavan, Verity Inc.: Randomized Algorithms and the Probabilistic Method
 Gerhard W?ginger, University of Twente: Approximation Algorithms and Inapproximability
ABOUT ADFOCS

ADFOCS is organized as part of the activities of the Algorithms and Complexity
Group and the International MaxPlanck Research School of the
MaxPlanckInstitut f?r Informatik. The scope of ADFOCS is international and it
is addressed mainly to young researchers at the PhD student or postdoc
level. The goal of ADFOCS is to provide an overview of selected topics
from the foundations of computer science and to highlight major research
directions in these areas.
This years ADFOCS will address topics like random sampling, randomized
algorithms, approximation algorithms as well as quantum computing.
The course will highlight important problems, techniques and ongoing
research in these areas.
It will also emphasize the discussion of open problems and the active
involvement of the participants, thus strengthening the links of
cooperation between young researchers of the field.
LOCATION & TRAVEL INFORMATION

ADFOCS will be held at the MaxPlanckInstitut f?r Informatik in
Saarbr?cken. Saarbr?cken is the capital of one of Germany's 16 states,
the Saarland. It is conveniently located in the center of Europe, on
the border of Germany with France, between Luxembourg, the SaarMosel
valley, Frankfurt and Strasbourg.
Being located on several main train and road routes, Saarbr?cken is
easily reachable from Frankfurt, Stuttgart, Paris or Luxembourg.
It also has its own international airport.
REGISTRATION

The registration fee covers lunches and social events. The early
registration deadline has already passed. Now the registration fee
is Euro 150.
Please note that the registration fee does not include accommodation,
although MPI can help for making reservations. Pernight price including
taxes and breakfast are ranging from 20 Euro (youth hostel, double room)
to about 50 Euro (hotel, single room).
ALCOMFT will provides some grants for graduate students and young
researchers. Priority will be given to applications of students and
young researchers from ALCOM sites.
CONTACT

The home page of ADFOCS with forms for registration and hotel
reservation and information about grants can be found at
http://www.mpisb.mpg.de/~adfocs
For further information or questions, send an email to
adfocs@mpisb.mpg.de.

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From gershon at cs.utah.edu Fri Aug 9 11:21:05 2002
From: gershon at cs.utah.edu (Gershon Elber)
Date: Mon Jan 9 13:41:07 2006
Subject: CFP  SM03
MessageID: <200208091621.g79GL5015423@faith.cs.utah.edu>
Dear comp. geom. fan
Please consider the attached Call for Papers for the coming Solid
Modeling 2003 meeting.
We look forward to your sumbissions
Sincerely
Gershon Elber, Technion, Israel
Vadim Shapiro, University of Wisconsin, USA
Program CoChairs, ACM Solid Modeling 2003

Call for Papers
SOLID MODELING 2003
Eighth ACM Symposium on Solid Modeling and Applications
University of Washington, Seattle, WA June 1620, 2003
Sponsored by ACM SIGGRAPH
The Solid Modeling symposia series is an international forum for the
exchange of recent research and applications of solid modelling, shape
modelling, and geometric computation in design, analysis and
manufacturing, as well as in the emerging biomedical, geophysical and
other areas. This highly successful symposium, which has been held
biannually since 1991, brings together prominent researchers, key
practitioners, and numerous students in the field. The symposium is
held annually, alternating its location between the USA and other
countries.
The Solid Modeling 2003 symposium will be held on the campus of
University of Washington in Seattle, WA, USA. In addition to
technical papers in plenary sessions, the program for Solid Modeling
2003 will include:
* academic and industrial tutorials
* keynote lectures
* panel and poster sessions
* best paper award at the symposium banquet
* sponsorship of students to attend the symposium
* social program
More information on the symposium can be found on the Solid Modeling
2003 web page:
http://www.ce.washington.edu/sm03
The papers submission schedule is as follows:
October 15, 2002: Abstracts due
November 30, 2002: Full papers due
February 10, 2003: Notice of acceptance and reviews
March 31, 2003: Final cameraready papers and extended abstracts
due
For details on how to submit abstracts and papers, please consult the
web page http://www.ce.washington.edu/sm03/submit_proc.
Abstracts are used to facilitate the review process and should be
150300 words in length. Papers are limited to 12 typeset pages in
length, including figures and references, and should present
previously unpublished original results. All papers will be
peerreviewed and can be selected for presentation at a plenary
session, or for presentation at a poster session, with publication in
the conference proceedings published by ACM Press. A revised version
of selected papers will also be published in special issues of related
scientific journals. Best paper award will be selected by a jury of
experts and will be presented at the symposium banquet.
Symposium CoChairs:
Pere Brunet, Polytechnical University of Catalonia, Barcelona, Spain
George Turkiyyah, University of Washington, USA
Program CoChairs:
Gershon Elber, Technion, Israel
Vadim Shapiro, University of Wisconsin, USA
Industrial Chair:
Jan Vandenbrande, Boeing
Topics of interest for Solid Modeling 2003 include, but are not
limited to:
Geometric and topological representations
Multiresolution models
Heterogeneous models
Geometric interrogations and reasoning
Computational geometry
Robustness of geometric computations
Blends, sweeps, offsets & deformations
Procedural, constraintbased and parametric modeling
Featurebased modeling
Conceptual design techniques
Product and assembly modeling
Representation conversion
Product data exchange
User interaction techniques
Haptic interfaces
Collaborative/distributed design
Virtual environments and prototypes
Reverse engineering
Engineering analysis using solid models
Engineering tolerances
Manufacturing and assembly planning
Computational support for new manufacturing technologies
Biomedical applications
Geoscientific applications
Entertainment applications

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From exact at cs.nyu.edu Fri Aug 9 14:51:15 2002
From: exact at cs.nyu.edu (Chee Yap)
Date: Mon Jan 9 13:41:07 2006
Subject: No subject
MessageID: <200208091751.g79HpFf13151@jinai.cs.nyu.edu>
===================== SOFTWARE RELEASE ANNOUNCEMENT ==========================
August 10, 2002:
Core Library Version 1.5 is now available for free download at
http://cs.nyu.edu/exact/core/
The Core Library (CORE) is a collection of C/C++ classes to support
computation with constructible real numbers (+,,x,/,sqrt), under a variety
of precision requirements.
Numerical nonrobustness is a widely acknowledged problem. It has proven
particularly intractable in the context of geometric algorithms where
numerical data and combinatorial data are intermixed in a strongly constrained
manner. Recent research in computational geometry has
demonstrated a variety of techniques based on the principles of
Exact Geometric Computation (EGC) that can address such problems.
A basic goal of our library is to make such techniques easily accessible to
the wider community of programmers and researchers.
Basic CORE Features:
 ease of use:
Any C/C++ programmer can write numerical or geometric
code that are fully robust just by calling our Library.
 ease of migration:
Many existing C/C++ programs can be converted into robust CORE
programs with minimal effort.
 natural and novel numerical accuracy model:
Users can choose and get the numerical accuracy that best fit
their applications.
 state of art technology:
The precisiondriven approach to EGC, best known root bounds,
filter technology, etc, will be incorporated into the library
as the field progresses. In this way, the user's application program
will automatically be upgraded (at the cost of recompilation).
 small system:
It can serve as the "robust core" of your own applications.
About 550KB (including source, extensions, demos)
when gmp and documentation is not included. Otherwise, the full
distribution is 3.6MB.
 extensively tested on Sun Sparc, Linux, cygwin and Windows platforms.
What is new with CORE 1.5 ?
 Faster code (can be significantly faster than CORE 1.4)
 Introduce headers for compiling CGAL with Core Library,
made compatibility modifications, and sample CGAL programs
 Introduce namespace CORE
 Improved root bounds (can be significant)
 Improved Expression evaluation algorithms
 Streamlined code for Expr and Real (mainly through template classes)
 Level 2 and 4 programs can now be compiled (with limited support)
 Header files (i.e., API) for Expr and Real are mutually consistent
(this was necessary to support Level 2 accuracy)
 More sample programs:
(a) improved hypergeometric package (all the elementary functions
in math.h are now available in Core)
(b) polynomial package with Sturm sequences and Newton
iteration for polynomail roots
 Compatibility with gmp 4.1, and g++ 3.1
 Updated Core Library Tutorial
 Bug fixes:
(a) bad initial root bound values for some constants (e.g., Expr(1.0))
(b) uMSB, lMSB (in Real, BigFloat, Filter classes)
(c) BigInt::ceilLg
We welcome your comments and input.
 Chee Yap (yap@cs.nyu.edu)
Sylvain Pion (pion@cs.nyu.edu)
Zilin Du (zilin@cs.nyu.edu)
August 10, 2002
=============================================
 Exact Computation Project
 Department of Computer Science
 Courant Institute of Mathematical Sciences
 New York University
 251 Mercer Street
 New York, NY 10012, USA

 For further information:
 http://cs.nyu.edu/exact/
 mailto://exact@cs.nyu.edu.

 Supported by NSF/ITR Grant CCR0082056.
=============================================
===================== SOFTWARE RELEASE ANNOUNCEMENT ==========================

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From ayellet at ee.technion.ac.il Tue Aug 13 10:56:41 2002
From: ayellet at ee.technion.ac.il (Ayellet Tal)
Date: Mon Jan 9 13:41:07 2006
Subject: CFP: ACM Symposium on Software Visualization
MessageID: <3D58ADA3.B83B0CA8@ee.technion.ac.il>
======================================================================
CALL FOR PAPERS
ACM Symposium on Software Visualization
SOFTVIS '03
June 1113, 2003, San Diego, USA
Collocated with FCRC'03
Sponsored by ACM SIGCHI, SIGGRAPH, SIGPLAN and SIGSOFT,
and in cooperation with ACM SIGCSE.
http://www.softvis.org/softvis03.html
======================================================================
Software visualization encompasses the development and evaluation of
methods for graphically representing different aspects of software,
including its structure, its abstract and concrete execution, and its
evolution. The goal of this symposium is to provide a forum for
researchers from different backgrounds (HCI, software engineering,
programming languages, visualization, computer science education) to
discuss and present original research on software visualization.
SoftVis '03 is the first meeting in a planned series of biennial
conferences. Our objective is to make the SoftVis series the premier
venue for presenting all types of research on software visualization.
Papers
======
We seek theoretical as well as practical papers on applications,
techniques, tools and case studies. Topics of interest include, but
are not restricted to, the following:
 Visualization of algorithms, including numerical, geometric, genetic,
distributed and graph algorithms
 Program visualization
 Protocol and log visualization (security, trust)
 Visualization of parallel programs
 Visualization in software engineering, e.g. UML diagrams
 Visualization of the software development process
 Visualization of data and processes in applications
 Educational software in computer science, in particular visualization
of computational models
 Graph drawing algorithm for software visualization
 Visualization of data base schemes
 Visual debugging
 3D software visualization
 Software visualization on the internet
 Program analyses and visualization
 Integration of software visualization tools and development
environments
 Empirical evaluation of software visualization system effectiveness
Papers should represent original, unpublished results and will be
rigorously
reviewed by the international Program Committee. Papers must be in
standard
ACM 2column format and cannot exceed 10 pages in total length. Authors
should prepare and electronically submit a PDF version of their paper.
Videos not exceeding 5 minutes in length can accompany a paper
submission.
Papers are due December 16, 2002. Further details on precise submission
guidelines will be forthcoming.
Tutorials
=========
A set of tutorials will immediately precede the main conference.
Tutorial
proposals of no more than 1 or 2 pages (for 90minute or 3hour
tutorials)
should be submitted to the program chair by January 15, 2003. Include
the
proposed title, brief description of material, intended audience,
assumed
background of attendees, and the name, affiliation, contact information
(email and phone), and brief biography of speaker(s). An electronic PDF
submission is preferred.
Deadlines
=========
Paper submission: December 16, 2002.
Tutorial submission: January 15, 2003.
Notification of acceptance: January, 27, 2003.
Final papers due: March, 3, 2003
Student Travel
==============
Conference Attendance Program for Students (CAPS) provides some
financial
support to graduate students, enabling them to attend SIGSOFTsponsored
conferences.
Venue
=====
SoftVis '03 is affiliated with the ACM Federated Computing Research
Conference, a collection of symposia occurring June 714 in San Diego,
CA.
For more details on registration, hotel and travel information, please
see
the FCRC 2003 web pages (www.acm.org/sigs/conferences/fcrc/).
Symposium Organizers
====================
General Chair:
Stephan Diehl, Saarland University, Saarbr?cken, Germany
Program Chair:
John T. Stasko, Georgia Institute of Technology, Atlanta, USA
Treasurer:
Christopher D. Hundhausen, University of Hawai'i, Honolulu, USA
Program Committee:
Margaret Burnett, Oregon State University, USA
Wim De Pauw, IBM Research, USA
John Domingue, Open University, UK
Steve Eick, Visintuit, USA
Hideki Koike, University of ElectroCommunications, Tokyo, Japan
Eileen Kraemer, The University of Georgia, USA
Hans Hagen, University Kaiserslautern, Germany
John Hosking, University of Auckland, New Zealand
Malcolm Munro, University of Durham, UK
Petra Mutzel, Vienna University of Technology, Austria
David Notkin, University of Washington, USA
Tom Naps, University of WisconsinOshKosh, USA
Marian Petre, Open University, UK
Steve Reiss, Brown University, USA
MargaretAnne Storey, University of Victoria, Canada
Erkki Sutinen, University of Joensuu, Finland
Ayellet Tal, Technion, Israel Institute of Technology, Israel
Reinhard Wilhelm, University of Saarland, Germany
Andreas Zeller, University of Saarland, Germany
More Information
================
For more information and questions about the SoftVis'03 Symposium,
please send email to diehl@cs.unisb.de and stasko@cc.gatech.edu.

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From aupetit at dase.bruyeres.cea.fr Tue Aug 20 14:26:43 2002
From: aupetit at dase.bruyeres.cea.fr (aupetit)
Date: Mon Jan 9 13:41:07 2006
Subject: volume of a ksimplex...
MessageID: <200208201126.NAA00231@tupai.bruyeres.cea.fr>
Hello,
I need to compute the volume of a ksimplex
knowing the coordinates of its vertices.
How should I proceed?
Any pointer?
Thanks
Michael

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From taubin at us.ibm.com Fri Aug 16 13:38:48 2002
From: taubin at us.ibm.com (Gabriel Taubin)
Date: Mon Jan 9 13:41:07 2006
Subject: Analytic formulas for distance between geometric shapes.
MessageID: <200208161638.g7GGcmV44990@sp1n293en1.watson.ibm.com>
> From: Dickinson, John
> To: compgeomdiscuss@research. belllabs. com (Email)
> 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 IMTINRC  Mark with chalk;
> email: john.dickinson@nrc.ca  Cut with axe."
You may be interested in these two papers that I wrote quite a while
ago. The problem was to decide which pixels are cut by an algebraic
curve. The approach was based on good (fast, accurate, etc.)
approximations to the distance from the center of the pixel to the
curve (works for higher dimmensions too). The main problem was to make
sure the singularities were properly dealt with.
An Accurate Algorithm for Rasterizing Algebraic Curves and Surfaces,
by G. Taubin.
IEEE Computer Graphics & Applications, March 1994.
Distance approximations for Rasterizing Implicit Curves,
by G. Taubin.
ACM Transactions on Graphics, January 1994
You can download the papers from the publications page in my IBM
web site. You will also find a Java applet demo there that you can
play with.

Dr. Gabriel Taubin taubin@computer.org
IBM T. J. Watson Research Center taubin@us.ibm.com
P.O.Box 704, Yorktown Heights, NY 10598 cell : (914)2177378
http://www.research.ibm.com/people/t/taubin phone: (914)7847095
fax : (914)7847667


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From wenger at cis.ohiostate.edu Fri Aug 16 09:26:20 2002
From: wenger at cis.ohiostate.edu (Rephael Wenger)
Date: Mon Jan 9 13:41:07 2006
Subject: Software for isosurface table generation
MessageID: <15708.61292.571854.930628@beta.cis.ohiostate.edu>
Isotable is a set of C++ classes and routines for generating
isosurface patches in convex polyhedra in arbitrary dimensions. It
constructs the isosurface patch as a subset of the convex hull of a
subset of polyhedra vertices and edge midpoints. (See "Isosurfacing
in higher Dimensions" by P. Bhaniramka, R. Wenger, and R. Crawfis,
Visualization, 2000, Salt Lake City Utah: IEEE Computer Society
Press.) Program genisotable generates isosurface lookup tables for
hypercubes and simplices in arbitrary (small) dimensions.
Isotable and genisotable source code is available at
http://www.cis.ohiostate.edu/graphics/isotable.
Source code includes K. Clarkson's program hull for generating convex hulls.

Dr. Rephael Wenger, Associate Professor, Ohio State U.,
Dept. of Comp. Sci., 2015 Neil Ave., Columbus, OH 432101277.
tel: (614) 2926253. email: wenger@cis.ohiostate.edu

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From bradb at shore.net Tue Aug 20 22:04:54 2002
From: bradb at shore.net (Brad Barber)
Date: Mon Jan 9 13:41:07 2006
Subject: volume of a ksimplex...
InReplyTo: <200208201126.NAA00231@tupai.bruyeres.cea.fr>
MessageID: <4.3.2.7.2.20020820210006.01766ee8@mail.attbi.com>
At 07:26 AM 8/20/2002, aupetit wrote:
>Hello,
>
>I need to compute the volume of a ksimplex
>knowing the coordinates of its vertices.
You can compute the volume from the convex hull, This
is practical up to about 8d. For example, using Qhull
DELL:/home/bbarber/cvswork/qhull3.2> rbox 200 D6  qconvex FA
Convex hull of 200 points in 6d:
Number of vertices: 155
Number of facets: 9280
Statistics for: rbox 200 D6  qconvex FA
Number of points processed: 175
Number of hyperplanes created: 36690
Number of distance tests for qhull: 71272
CPU seconds to compute hull (after input): 0.651
Total facet area: 2.6783254
Total volume: 0.23360794
Brad
http://www.geom.umn.edu/software/qhull [currently not responding]
Spanish mirror:
http://www6.uniovi.es/ftp/pub/mirrors/geom.umn.edu/software/ghindex.html
>How should I proceed?
>Any pointer?
>
>Thanks
>
>Michael
>
>
>
>The compgeom mailing lists: see
>http://netlib.belllabs.com/netlib/compgeom/readme.html
>or send mail to compgeomrequest@research.belllabs.com with the line:
>send readme
>Now archived at http://www.uiuc.edu/~sariel/CG/compgeom/maillist.html.

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From mount at cs.umd.edu Thu Aug 22 17:39:08 2002
From: mount at cs.umd.edu (Dave MOUNT)
Date: Mon Jan 9 13:41:07 2006
Subject: SoCG'03 Call for Papers
MessageID:
CALL FOR PAPERS, VIDEOS AND MULTIMEDIA
19th ACM Symposium on
Computational Geometry
http://www.cs.umd.edu/areas/Theory/socg/
June 810, 2003  San Diego, USA
In conjunction with FCRC 2003
Sponsored by ACM SIGACT and SIGGRAPH
CALL FOR PAPERS

The 19th ACM Symposium on Computational Geometry, featuring
both theoretical and applied research, and a video review, will be held
at the Town and Country Resort & Conference Center in San Diego (USA) as
part of the Federated Computer Research Conference (FCRC 2003). We
invite highquality submissions in the following research areas:
* Geometric algorithms and combinatorial geometry;
* Implementation issues and applications of computational geometry.
The accepted papers will be published in the symposium proceedings
published by the ACM and distributed at the symposium. The proceedings will
also be available separately for purchase from the ACM. A selection of
papers from the conference will be invited to special issues of
journals. There will be a prize for the best studentauthored paper (see
below).
Research in computational geometry is very diverse, ranging from applied
to theoretical, and the topics of the Symposium reflect this. Examples
of more applied topics are: experimental analysis of algorithms and data
structures; mathematical and numerical issues arising from
implementations; and novel uses of computational geometry in other
disciplines, such as robotics, computer graphics, geometric and solid
modeling, manufacturing, geographical information systems, and molecular
biology. Examples of more theoretical topics are: design and theoretical
analysis of geometric algorithms and data structures; lower bounds for
geometric problems; and discrete and combinatorial geometry.
Paper Submission
Electronic submissions are preferred, but authors may instead mail 8
copies of an extended abstract to arrive by December 5, 2002 to either
of the two Program CoChairs
Mark de Berg David Mount
Dept. of Computer Science Dept. of Computer Science
TU Eindhoven University of Maryland
P.O.Box 513, 5600 MB Eindhoven College Park, MD 20742
the Netherlands USA
markdb@cs.uu.nl mount@cs.umd.edu
Important Dates
Thu, December 5, 2002 Papers due
Sat, February 15, 2003 Notification of acceptance or rejection of papers
Sat, March 15, 2003 Cameraready papers due
June 810, 2003 Symposium
Submission Guidelines
Papers should be submitted in the form of an extended abstract, which
begins with the title of the paper, each author's name, affiliation, and
email address, followed by a succinct statement of the problems and
goals that are considered in the paper, the main results achieved, the
significance of the work in the context of previous research, and a
comparison to past research. The abstract should provide sufficient
detail to allow the program committee to evaluate the validity, quality,
and relevance of the contribution. The entire extended abstract should
not exceed 10 pages, using 11 point or larger font and with at least
oneinch margins all around. If the authors consider it absolutely
essential to include additional technical details that do not fit into
10 pages, these details may be added in a clearly marked appendix that
should appear after the body of the paper and the references; this
appendix will not be regarded as a part of the submission and will be
considered only at the program committee's discretion.
Abstracts in hard copy must be received by December 5, 2002. Abstracts
in electronic form are due by December 5, 5:00 PM EST; for further
details please visit the conference webpage,
http://www.cs.umd.edu/areas/Theory/socg/
These are firm deadlines; late submissions will not be considered.
Authors will be notified of acceptance or rejection by February 15,
2003. A full version of each contribution in final form will be due by
March 15, 2003 for inclusion in the proceedings.
Best Student Paper Award
A prize will be given to the author(s) of the best studentauthored
paper. The program committee may decline to make the award, or may
split it among more than one paper. A paper is eligible if all of its
authors are fulltime students at the time of submission. This must be
indicated during the electronic submission process, or, for hard copy
submissions, in the cover letter.
Conference Chair
Steve Fortune (Bell Labs)
Program Committee
Mark de Berg, cochair (TU Eindhoven)
Prosenjit Bose (Carleton University)
Erik Demaine (MIT)
Tamal Dey (The Ohio State University)
Olivier Devillers (INRIA Sophia Antipolis)
Leo Guibas (Stanford University)
Matthew Katz (BenGurion University)
Joe Mitchell (Stony Brook University)
David Mount, cochair (University of Maryland)
Takeshi Tokuyama (Tohoku University)
Gert Vegter (University of Groningen)
Emo Welzl (ETH Zurich)
CALL FOR VIDEOS AND MULTIMEDIA

Videos are sought for the 12th Annual Video Review of Computational
Geometry. This video review showcases the use of visualization in
computational geometry for exposition and education, as an interface and
a debugging tool in software development, and for the visual exploration
of geometry in research. Algorithm animations, visual explanations of
structural theorems, descriptions of applications of computational
geometry, and demonstrations of software systems are all appropriate.
Videos that accompany papers submitted to the technical program
committee are encouraged.
This year the video review is experimenting with interpreting "video"
broadly as any form of multimedia that can be rendered visually over
time. In addition to the standard notion of videos (moving picture and
sound), we allow submissions of PowerPoint animations, Java applets, and
limited forms of other computed programs that generate video. These
programs must have a "demo mode" that requires no interaction (after
e.g. pressing a "demo" button) and demonstrates the program
automatically. Audio can be generated by the program itself (e.g.,
PowerPoint animations can have a voiceover), or specified by a separate
track. We prefer that such submissions are accompanied by standard
videos, but when such preparation is difficult for the authors, the
video rendering will be prepared by the video committee. All of these
nonstandard arrangements must be coordinated with the video chair at
least two weeks prior to submission.
Accepted videos will be collected onto a DVD and distributed to
attendees of the conference. The conference proceedings will include a
submitted one or twopage textual description of each video. In
addition, authors will have the opportunity to give short presentations
about accepted videos, how they were made, and brief background. These
presentations will be interleaved with the showing of the videos during
a video review session at the conference.
Important Dates
Fri, February 7, 2003 Video submissions due
Fri, February 21, 2003 Notification of acceptance or rejection of videos
Sat, March 15, 2003 Video abstracts due
Fri, April 4, 2003 Final versions of videos due
June 810, 2003 Symposium
Video Submission
Submissions are due by February 7, 2003. We strongly encourage
electronic submission of videos. Electronic submissions should be in
MPEG2 format, although other arrangements can be made with the video
chair. Specific requirements on encoding, instructions for preparing
submissions, and methods of submission will be detailed soon on the
webpage. Arrangements for nonelectronic submissions must be made at
least two weeks prior to the deadline with the video chair.
Each video must be accompanied by a one or twopage description of the
material shown in the video, and where applicable, the techniques used
in the implementation. References to additional material describing the
contents of the videos, such as accompanying papers, are encouraged.
Please format the descriptions following the guidelines for ACM
proceedings. The descriptions should be submitted electronically by
emailing a PostScript or PDF file to the video chair. If electronic
submission is impossible, authors should mail seven hardcopies of the
description to the video chair:
Erik Demaine
MIT Laboratory for Computer Science
200 Technology Square
Cambridge, Massachusetts 02139
USA
Phone: (+1) 6172536871
Fax: (+1) 6172530415
edemaine@mit.edu
Notification
Authors will be notified of acceptance or rejection, and given
reviewers' comments by February 21, 2003. For each accepted video, the
final version of the textual description is due by March 15, 2003 for
inclusion in the proceedings. Final versions of accepted videos are due
by April 4, 2003.
Video Program Committee
Erik Demaine, chair (MIT)
Fredo Durand (MIT)
Steven Gortler (Harvard University)
Piotr Indyk (MIT)
Diane Souvaine (Tufts University)
Seth Teller (MIT)
ShangHua Teng (Boston University)

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From aupetit at dase.bruyeres.cea.fr Thu Aug 22 17:37:44 2002
From: aupetit at dase.bruyeres.cea.fr (aupetit)
Date: Mon Jan 9 13:41:07 2006
Subject: volume of a ksimplex...
References:
MessageID: <200208221437.QAA19124@tupai.bruyeres.cea.fr>
William Flis wrote:
> > I need to compute the volume of a ksimplex
> > knowing the coordinates of its vertices.
>
> For a triangle:
>
> Area = Abs( 1 x1 y1 )
>  1 x2 y2 
>  1 x3 y3 
> 
> 2
>
> For a tetrahedron:
>
> Volume = Abs( 1 x1 y1 z1 )
>  1 x2 y2 z2 
>  1 x3 y3 z3 
>  1 x4 y4 z4 
> 
> 6
>
> I believe this generalizes to any dimension k, with the denominator equal to
> (k!).
>
> William J. Flis Director of Research
> DE Technologies, Inc.
> 3620 Horizon Drive
> King of Prussia, PA 19406
> Voice: 6102709700 x130
> Fax: 6102709733
> mailto:flis@detk.com
I forgot to mention that in my case
the vertices of a ksimplex are given in R^n
where n may be greater than k.
I got this formula
 det (W*W^t)  ^(1/2)
Volume_k = 
k!
on the site:
http://www.math.washington.edu/~hillman/PUB/volume
with W the matrix with k rows and n columns
where W=(v_1v_0)
(v_2v_0)
( ... )
(v_kv_0)
with row vectors v_i the k+1 vertices of the
ksimplex in R^n.
W^t denotes the transpose of W.
Are both formulae equivalent when n=k?
Thanks
Michael
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From flis at detk.com Thu Aug 22 10:31:15 2002
From: flis at detk.com (William Flis)
Date: Mon Jan 9 13:41:07 2006
Subject: volume of a ksimplex...
InReplyTo: <200208201126.NAA00231@tupai.bruyeres.cea.fr>
MessageID:
> I need to compute the volume of a ksimplex
> knowing the coordinates of its vertices.
For a triangle:
Area = Abs( 1 x1 y1 )
 1 x2 y2 
 1 x3 y3 

2
For a tetrahedron:
Volume = Abs( 1 x1 y1 z1 )
 1 x2 y2 z2 
 1 x3 y3 z3 
 1 x4 y4 z4 

6
I believe this generalizes to any dimension k, with the denominator equal to
(k!).
William J. Flis Director of Research
DE Technologies, Inc.
3620 Horizon Drive
King of Prussia, PA 19406
Voice: 6102709700 x130
Fax: 6102709733
mailto:flis@detk.com

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From hanwen at cs.uu.nl Thu Aug 22 19:48:53 2002
From: hanwen at cs.uu.nl (HanWen Nienhuys)
Date: Mon Jan 9 13:41:07 2006
Subject: volume of a ksimplex...
InReplyTo: <200208201126.NAA00231@tupai.bruyeres.cea.fr>
References: <200208201126.NAA00231@tupai.bruyeres.cea.fr>
MessageID: <15717.5621.918258.366945@meddo.cs.uu.nl>
aupetit@dase.bruyeres.cea.fr writes:
> Hello,
>
> I need to compute the volume of a ksimplex
> knowing the coordinates of its vertices.
>
> How should I proceed?
> Any pointer?
Assuming you're posing this is in kdimensional space, that would be
1/(k!) * det (x_0, .. , x_k),
where x_j is the k+1  vector consisting of the k coordinates of the
jth point and a 1 as k+1st coordinate.

HanWen Nienhuys  hanwen@cs.uu.nl  http://www.cs.uu.nl/~hanwen/

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From jrs at buffy.EECS.Berkeley.EDU Fri Aug 23 16:32:30 2002
From: jrs at buffy.EECS.Berkeley.EDU (Jonathan Shewchuk)
Date: Mon Jan 9 13:41:07 2006
Subject: volume of a ksimplex...
InReplyTo: Your message of "Thu, 22 Aug 2002 16:37:44 +0200."
<200208221437.QAA19124@tupai.bruyeres.cea.fr>
MessageID: <200208232232.PAA02407@buffy.EECS.Berkeley.EDU>
> I got this formula
>
>  det (W*W^t)  ^(1/2)
> Volume_k = 
> k!
>
> on the site:
> http://www.math.washington.edu/~hillman/PUB/volume
>
> with W the matrix with k rows and n columns
> where W=(v_1v_0)
> (v_2v_0)
> ( ... )
> (v_kv_0)
>
> with row vectors v_i the k+1 vertices of the
> ksimplex in R^n.
>
> W^t denotes the transpose of W.
>
> Are both formulae equivalent when n=k?
Almost. When n = k, this formula is equivalent to the formulae William Flis
and HanWen Nienhuys gave youexcept that this formula always returns a
positive volume, whereas the Flis and Nienhuys formulae gives you orientation
information in the sign of the result (e.g. are the triangle's vertices in
clockwise or counterclockwise order?).
Note that when n = k, W is square, so  det (W*W^t)  ^(1/2) = det(W),
and det(W) is obviously faster to compute than  det (W*W^t)  ^(1/2)
(and gives you the orientation information). So for the special case n = k,
I recommend using
Volume_k = det(W) / k!
Although the formulae are numerically equivalent up to sign, they are very
different when floatingpoint roundoff error enters the picture. The Flis
and Nienhuys formulae can have unnecessarily large errors, especially if the
simplex is far from the origin. The formula on the Washington site (and the
formula det(W) / k! when n = k) is numerically much better behaved. (If you
care to know why, download my "Lecture Notes on Geometric Robustness" from
http://www.cs.berkeley.edu/~jrs/mesh/ under Lecture 13, and read Section 2.)
Jonathan Shewchuk
UC Berkeley

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From hanwen at cs.uu.nl Fri Aug 23 16:14:29 2002
From: hanwen at cs.uu.nl (HanWen Nienhuys)
Date: Mon Jan 9 13:41:07 2006
Subject: volume of a ksimplex...
InReplyTo: <200208221437.QAA19124@tupai.bruyeres.cea.fr>
References:
<200208221437.QAA19124@tupai.bruyeres.cea.fr>
MessageID: <15718.13621.139428.733086@meddo.cs.uu.nl>
aupetit@dase.bruyeres.cea.fr writes:
>  det (W*W^t)  ^(1/2)
> Volume_k = 
> k!
>
> on the site:
> http://www.math.washington.edu/~hillman/PUB/volume
>
> with W the matrix with k rows and n columns
> where W=(v_1v_0)
> (v_2v_0)
> ( ... )
> (v_kv_0)
>
> with row vectors v_i the k+1 vertices of the
> ksimplex in R^n.
>
> W^t denotes the transpose of W.
>
> Are both formulae equivalent when n=k?
Almost. When W has rank n, then det (W*W^T) = det(W)^2. The above
formula always yields a positive answer. For an ndimensional simplex,
the determinant of the coordinate vectors can be negative depending on
the orientation of the simplex.
The formulation which uses a (k+1)x(k+1) determinant is more symmetric
than the one that selects an origin vector (v_0 above) and uses the k
x k determinant. I'm not sure if this has consequences for numerical
precision and/or stability when using inexact computation.

HanWen Nienhuys  hanwen@cs.uu.nl  http://www.cs.uu.nl/~hanwen/

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From honestcox at excite.com Wed Aug 28 12:29:57 2002
From: honestcox at excite.com (Bradford Cox)
Date: Mon Jan 9 13:41:07 2006
Subject: Inner offset Polygons
MessageID: <20020828152957.AB3651E48A@xmxpita.excite.com>
Hello all, I am trying to solve a problem which is the calculation of an inner offset polygon based on a set of original points and a given offset distance. It is acceptable for the inner polygon to not be a "mirror" image of the original polygon since certain sides will converge to zero length, etc. Currently my focus has been in the area of straight skeletons. I intend on first creating a straight skeleton and then somehow generating the sides of the new inner polygon based on the the skeleton lines. (I am not sure how to do this just yet!) Does anyone have any suggestions for either the straight skeleton approach or some other approach? Thanks, Bradford Cox

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From edemaine at mit.edu Thu Aug 29 12:23:30 2002
From: edemaine at mit.edu (Erik Demaine)
Date: Mon Jan 9 13:41:07 2006
Subject: Inner offset Polygons
InReplyTo: <20020828152957.AB3651E48A@xmxpita.excite.com>
MessageID:
Dear Bradford,
Yes, if you want general orthogonal offsets, you'll need to compute the
straight skeleton. Once you have the straight skeleton, it is not hard to
compute offsets. It is useful to have extra combinatorial information about
the straight skeleton: each skeleton edge is the bisector of two polygon edges,
so you can store the two polygon edges next to each skeleton edge.
Now, to compute an offset, pick a point on the straight skeleton of the
appropriate distance to the appropriate edge, and construct parallels to the
polygon edges and reflect whenever you hit an edge of the straight skeleton.
There are existing implementations of the straight skeleton which you may
want to use. I think this is a recent one:
http://fractal.dam.fmph.uniba.sk/~sccg/proceedings/1998/Felkel.ps.gz
Hope this helps,
Erik

Erik Demaine  edemaine@mit.edu  http://theory.lcs.mit.edu/~edemaine/
On Wed, 28 Aug 2002, Bradford Cox wrote:
> Hello all, I am trying to solve a problem which is the calculation of an
> inner offset polygon based on a set of original points and a given offset
> distance. It is acceptable for the inner polygon to not be a "mirror" image
> of the original polygon since certain sides will converge to zero length,
> etc. Currently my focus has been in the area of straight skeletons. I intend
> on first creating a straight skeleton and then somehow generating the sides
> of the new inner polygon based on the the skeleton lines. (I am not sure how
> to do this just yet!) Does anyone have any suggestions for either the
> straight skeleton approach or some other approach? Thanks, Bradford Cox

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From blk at maiainstitute.org Fri Aug 30 09:56:00 2002
From: blk at maiainstitute.org (Brandon Kohn)
Date: Mon Jan 9 13:41:07 2006
Subject: polygonization
MessageID: <001001c24ff2$4d16b950$0a00a8c0@maiainstitute.org>
Hello all,
I have a problem that I'm working on that requires an algorithm that will
build polygons from an initial set of line segments in a 2D plane. This
seems like the type of problem that has probably been solved optimally, but
I haven't had much luck in finding any source code out on the net, or any
good papers in the literature online. Could someone please point me in the
proper direction?
Thanks for any help
____________________________________________________________
Brandon Kohn Tel.: +377 97 97 41 51
Software Engineer/Sys Admin
The Maia Institute Fax.: +377 97 97 41 59
Le Patio Palace
41, Avenue Hector Otto
MC 98000 Monaco
blk@maiainstitute.org
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