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
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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
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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"
}
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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
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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.
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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
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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.
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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
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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.)
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