Subject: NA-NET distribution message

From: [email-masked]
Date: Sun, 24 Sep 89 21:48:24 PDT

NA Digest   Sunday, September 24, 1989   Volume 89 : Issue 37

Today's Editor: Cleve Moler

Today's Topics:

      Checking Positive Matrices
      Address Change for Martin Berzins
      Address Change of Masaaki Shimasaki
      Algorithms for Radon Transforms
      CWI-Symposia on Parallel Scientific Computing
      Positions at University of Maryland Baltimore County
      David Kamowitz
      Householder Symposium XI
      Positions at RIACS

-------------------------------------------------------

From: Stephen Boyd <[email-masked]>
Date: Sat, 16 Sep 1989 9:26:20 PDT
Subject: Checking Positive Matrices

Does anyone know of an algorithm for determining whether a matrix is P
or P0, that is NOT combinatoric in the size of the matrix? (a matrix
is P if the determinants of all principal submatrices are positive).
I am not interested in algorithms that work for some matrices (eg
symmetric (!!), or less trivially, matrices with negative offdiagonal
elements); the algorithm must work for general matrices.

Stephen Boyd
[email-masked]

------------------------------

From: Martin Berzins <[email-masked]>
Date: Mon, 18 Sep 89 09:37:04 EDT
Subject: Address Change for Martin Berzins

Having finished my sabbatical at RPI, 
from 24th September my new email address
will be [email-masked] 
Martin Berzins.

------------------------------

From: Masaaki Shimasaki <[email-masked]>
Date: Tue, 19 Sep 89 14:11:56 JST
Subject: Address Change of Masaaki Shimasaki

Please change the E-mail  address of Simasaki at Data Processing
Center, Kyoto University to

 [email-masked]

Thank you.
[email-masked]

------------------------------

From: Per Christian Hansen <[email-masked]>
Date: Wed, 20 Sep 89 14:07:18 -0100
Subject: Algorithms for Radon Transforms

               NUMERICAL ALGORITHMS FOR
          RADON AND INVERSE RADON TRANSFORMS

Does anybody on the na-net have good numerical algorithms
for computing the Radon transform, and for performing the
inverse Radon transformation?

Since this is a very general problem, let me add that I'm
particularly interested in algorithms for use in seismics.

I'm fully aware that the inverse Radon transform is an ill-
posed problem and, preferably, should be treated with this
aspect in mind.  However, I do not know the degree of ill-
posedness of the problem, i.e. the decay rate of the singu-
lar values of the Radon integral operator.

Any hints, comments or other advice is welcome.

Per Christian Hansen
UNI-C (the Danish University Computing Center)
Building 305
Technical University of Denmark
DK-2800 Lyngby
Denmark

email: na.phansen @ na-net.stanford.edu

------------------------------

From: Herman te Riele <[email-masked]>
Date: Thu, 21 Sep 89 16:56:06 +0200
Subject: CWI-Symposia on Parallel Scientific Computing

                C A L L    F O R    A B S T R A C T S

            CWI-SYMPOSIA ON PARALLEL SCIENTIFIC COMPUTING

               in collaboration with TUD, UvA and IMACS

In collaboration with TUD (Technical University Delft), UvA (University of
Amsterdam) and IMACS (International Association for Mathematics and 
Computers in Simulation), CWI will organise five one-day Symposia on
Parallel Scientific Computing. Dates are: 2 Febr., 6 April, 8 June,
7 Sept. and 2 Nov. 1990. Place is CWI Amsterdam, The Netherlands.

Attention will focus on new developments in numerical algorithms for
parallel computing systems, on software tools for parallel computing
(including libraries) and on applications in science and technology
(e.g., fluid dynamics, mechanics, chemistry).

Depending on possible external funding, a number of leading experts
in these fields will be invited to speak.

The organising committee consists of Prof.dr. Th.J. Dekker (UvA), 
Dr.ir. H.J.J. te Riele (CWI) and Prof.dr. H.A. van der Vorst (TUD and CWI).
Abstracts of possible contributions to the first three meetings (2 Febr.,
6 April and 8 June 1990) are solicited now.
The deadline for submission of abstracts is Nov. 1, 1989.
Notification of acceptance will be sent by Jan. 1, 1990.

A special issue of the IMACS Journal "Applied Numerical Mathematics"
will be devoted to the proceedings of the symposia. Contributions will be
subject to the usual refereeing process of IMACS.

Please send for electronic application form.

                                    (On behalf of)
                                    the organising committee,
                                
                                    Herman J.J. te Riele
                                    Centre for Mathematics and 
                                    Computer Science (CWI)
                                    Kruislaan 413
                                    1098 SJ  Amsterdam
                                    The Netherlands
                                    e-mail: [email-masked]

------------------------------

From: Thomas Seidman <[email-masked]>
Date: 21 Sep 89 13:30:00 EDT
Subject: Positions at University of Maryland Baltimore County

		POSITION ANNOUNCEMENT --- UMBC

	The Department of Mathematics and Statistics at the University of 
Maryland Baltimore County has been authorized to recruit for three positions
for the Fall of 1990. At least one of these will be at a senior level; at
least one will be in Statistics.

	The Department has strengths in control theory and optimization, in 
ordinary and partial differential equations and mathematical modelling, in
numerical analysis and scientific computing, and in probability and statistics.
It seeks strong applicants in these or related areas.

	Interested candidates should send a curriculum vitae, a list of
publications, and three letters of reference to:
		James M. Greenberg, Chairman
		Department of Mathematics and Statistics
		University of Maryland Baltimore County
		Baltimore, MD   21228
Applicants will be considered until three suitable candidates have been found.

	THE UNIVERSITY IS AN EQUAL OPPORTUNITY EMPLOYER AND SPECIFICALLY
INVITES APPLICATIONS FROM WOMEN, MINORITIES, AND DISABLED PERSONS.

------------------------------

From: Robert Voigt <[email-masked]>
Date: Fri, 22 Sep 89 08:22:09 EDT
Subject: David Kamowitz

On September 16 David Kamowitz died of complications associated with a long
bout with cancer.

David came to ICASE from Wisconsin three years ago.  He struggled with his
disease for over two years, admonishing his doctors to keep trying up until
the very end.  He was one of the most courageous people I have known and I
consider myself fortunate to have been associated with him.

Bob Voigt

------------------------------

From: Ake Bjorck <[email-masked]>
Date: Fri, 22 Sep 89 14:50:43 +0200
Subject: Householder Symposium XI

       THE HOUSEHOLDER SYMPOSIUM XI MEETING ON NUMERICAL ALGEBRA

   The Householder Symposium XI on numerical algebra will be held
during the week of June 18--22, 1990 at Tylosand, Halmstad on the west 
coast of Sweden. This meeting is the eleventh in a series, previously called 
the Gatlinburg Symposia. It has been agreed to rename all subsequent
Gatlinburg Symposia to honor Alston S. Householder, one of the pioneers
in Numerical Linear Algebra and organizer of the first four
Gatlinburg meetings. The meeting is an international conference of experts
in the field of Numerical Algebra. The format of the meeting is a sequence of 
invited papers during the day and special workshops organized by the
participants in the evening. There is no formal program, but traditionally
a few topics are emphasized. For this meeting they will be large scale 
nonsymmetric linear algebra problems, least squares, and matrix inertia
and stability.

   The meeting is being organized by the Householder committee, in cooperation
with the SIAM Activity Group on Linear Algebra.
Chairman of the committee for this meeting, and in charge of the 
local organization is Ake Bjorck of Linkoping University, Sweden.

    The traditional format of the Householder Symposia requires that 
the attendance is limited. The organizing committee invites all qualified 
persons to apply to attend. The application should consist of a vita and an 
extended abstract (about two pages) of a paper you would present if invited to 
speak. The latter will be used by the committee in planning the program. 
Material should be sent before November 1, 1989 to

                    Ake Bjorck
                    Department of Mathematics
                    Linkoping University
	            S-581 83 Linkoping, SWEDEN

   The Gatlinburg Conferences are international workshops on the theoretical
and numerical aspects of linear algebra and its application. They were started
by Alston S. Householder and initially held at Gatlinburg, Tennessee,
approximately once every three years. After the first four meetings it was
decided to hold the conferences under the same name at varying locations.
The custom has become to have every third meeting in Europe. For a review
of the earlier meetings see an article in SIAM Review [1977].  A complete
list of previous meetings is given below:

I.   April    1961    Gatlinburg, Tennessee             A. S. Householder
II.  October  1963    Gatlinburg, Tennessee             F. Olver 
III. April    1964    Gatlinburg, Tennessee             A. S. Householder 
IV.  April    1969    Gatlinburg, Tennessee             A. S. Householder 
V.   April    1972    Los Alamos, New Mexico            A. S. Householder 
VI.  December 1974    Hopfen am See, Germany            F. L. Bauer 
VII. December 1977    Asilomar, California              G.H. Golub 
VIII.July     1981    Oxford, England                   J.H. Wilkinson 
IX.  July     1984    Waterloo, Canada                  J.A. George 
X.   October  1987    Fairfield Glades, Tennessee       G.W. Stewart 

   The Gatlinburg meetings brings together theoreticians, numerical analysts,
and application researchers from all over the world. During the day, there
are lectures (no parallel sessions) by people judged to be doing especially
interesting work in their areas. In the evenings, the participants organize
special sessions or minisymposia over areas of current interest.
Traditionally the interaction is very open and intense, and many workers
attribute some of their best results to ideas that originated at a
Gatlinburg conference. The meetings have played an important part
in the evolution of scientific computing, and it is hard to overstate the role 
these conferences have played in fostering and sustaining international 
cooperation in numerical algebra.

   Attendance at the Gatlinburg Conferences is by invitation, and procedures 
have been devised that hopefully insure that a fair selection is made.
It is anticipated that 100-120 people will be invited to the present meeting.
Even though several open meetings are held in linear algebra, these conferences
are unique in that here the best people in the field from all countries have
a chance to get together and interact informally.

   Hotel Tylosand is situated by the sea on the west coast of Sweden. The hotel
has recently been renovated and modernized and is a conference center of the
best international class. The location is removed from any big cities and
offers excellent opportunities for physical exercise.
Room and buffet breakfast is approximately $65 single and $60 double occupancy.
It is hoped that the meeting can be run with the same modest registration
fee $50 as the previous meeting at Fairfield Glades. 

------------------------------

From: Rich Sincovec <[email-masked]>
Date: Fri, 22 Sep 89 14:55:07 PDT
Subject: Positions at RIACS

INSTITUTE:      RIACS
	    
JOB TITLE:	FACILITY RESEARCH ASSOCIATE

LOCATION:	MOUNTAIN VIEW, CA at NASA AMES

  The Research Institute for Advanced Computer Science (RIACS) is an
  institute of the Universities Space Research Association operating under
  a cooperative agreement with the NASA Ames Research Center and is devoted
  to the conduct of research in computer science aimed at the challenging
  problems faced by NASA.  Current research programs include development, 
  integration, and evaluation of advanced computer science technologies 
  supporting the use of multiple resources connected by networks, the study
  of advanced numerical algorithms and parallel computing architectures,
  and memory models for robotics and other applications. 
	
FACILITY DESCRIPTION:

  The RIACS computing facility serves our staff of approximately forty
  individuals and consists of the following equipment:
  
  Sequent Balance 21000s, Encore Multimax, Ardent, Stellar, NeXT,
  various X Stations, network access to NASA Ames computers including
  Cray Y_MP, Cray 2 and CM-2, 26 Sun 3 workstations with 3 dedicated
  file servers running Sun OS 4.0, uucp server, internet gateway to
  BARRNET (NSFNET).
    
  The RIACS facility is principally based on UNIX and X Windows.

RESPONSIBILITIES INCLUDE:
  * Systems programming and maintenance on the computing facility.
  * Systems administration for the Sun network.
  * Applications programming supporting research projects
    in scientific computing with an emphasis on numerical algorithms
    for parallel computer architectures.
  * Frequent interaction with RIACS and NASA scientists.
  
EDUCATION/EXPERIENCE
  * M.S. in Computer Science or equivalent experience
  * Two or more years experience working with UNIX, including
    experience with the kernel and net-working.
  * Ability to work well with people and excellent communications skills
  * U.S. Citizenship or Permanent Residence.

INTERESTED PARTIES:
  Send your resume to: [email-masked]
  Richard Sincovec
  RIACS - Research Institute for Advanced Computer Science
  Mail Stop 230-5
  NASA Ames Research Center
  Moffett Field, CA 94035
  Office Phone: (415)694-4342   FAX Number:   (415)961-8467

------------------------------

End of NA Digest
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