14:00 - 14:15 Patrick Aerts, NCF (bio) Introduction: To acquire a new national supercomputer
14:15 - 15:00 Mark Portney, SGI (bio) ccNUMA technology at SGI (abs)
15:00 - 15:45 Aad van der Steen, UU/NCF (bio) Benchmarking for a large scale computing facility (abs)
15:45 - 16:00 Tea Break
16:00 - 18:00 Session 2
16:00 - 16:45 Harrie Weinands, EUR (bio) What are Bones Made For? (abs)
16:45 - 17:30 Arthur Veldman, RUG (bio) Unraveling turbulence (abs)
General Information about the speakers
Patrick Aerts
Dr. Patrick Aerts is the director of the Dutch National Computing Facilities Foundation.
Mark Portney
Dr. Mark Portney received a BS in Math and Physics at UCLA in 1976, MS in
Physics (theoretical solid state) at Arizona State University (ASU) in
1978, and PhD (theoretical particle physics) at ASU in 1983. After postdoc
work in Geophysics at ASU, he worked at Texaco in Houston from 1984 to
1993. He was involved with all aspects of seismic data processing, and
worked on a variety of computers. He moved to SGI's Technology Center in
1993 in order to work on SGI multiprocessing computer systems. His
responsibilities since then have been benchmarking and performance
engineering for technical computing. He is especially interested in
high-performance I/O.
Aad van der Steen
Dr. Aad van der Steen studied mathematics at the Delft University of
Technology while providing computational support at the Interuniversity
Reactor Institute in Delft. After a short stay as a mathematical modeller
at the Environmental Ministry he was employed at the Computing Centre of
the Utrecht University and as an advisor to NCF for High Performance
Computing. He obtained his PhD. from the Computational Physics Department
of the Utrecht University on the subject of benchmarking High Performance
computers. He currently works for this department and for the NCF.
Harrie Weinands
Dr. Harrie Weinans studied mechanical engineering at University of Twente
(degree 1986). PhD in medical science from University of Nijmegen (degree
1991).From 1994-1996 employed at Rush Medical Center, Chicago. From 1997
until now employed at Erasmus University Rotterdam. Research interest: the
interaction between the biological and mechanical processes in bone tissue
in relation to the fixation of orthopaedic implants and bone fracture risk.
Arthur Veldman
Arthur Veldman obtained a Ph.D. in Applied Mathematics from the University
of Groningen. In 1977 he joined the National Aerospace laboratory NLR in
Amsterdam, where he was involved in various projects in the area of
computational aero- and hydrodynamics. In addition, between 1984 and 1990
he was part-time professor of CFD at Delft University of Technology. In
1990 he returned to Groningen, where he now occupies the chair in
Computational Mechanics.
Abstracts
ccNUMA technology at SGI
To be announced.
Benchmarking for a large scale computing facility
The Dutch National Computer Facilities Foundation (NCF) commissioned a new
computer system to replace a Cray C90 that is used nationally by many
universities and research institutions. Part of this process was an
extensive benchmark to evaluate the performance of the candidate systems.
We describe the structure and methodology of this benchmark and present
some of the results that may be disclosed. The benchmark results have, at
least for a major part, lead to the procurement of the 1 Tflop/s SGI SN-1
system of which the installation will be completed in November 2000.
What are Bones Made For?
Short overview of numerical simulations of various aspects of bone tissue.
The internal morphology of bone consists of an irregular spongy (foam) like
structure. This has important consequences for the load bearing function of
bone. Numerical simulations of the load distribution through the
architecture were performed. This elucidates how effective the structure
can withstand loading. In addition it can be simulated how bone is
continuously being resorbed and replaced by cells. The interaction between
the cellular processes and the load distribution will be discussed. This
research can be used to understand the mechanics of bone which has
important implications in diseases such as osteoporosis and arthroses.
Unraveling turbulence
Turbulent flows possess many, seemingly chaotic, details with small length-
and time scales. Much research is going on into the character of
turbulence: the main question is when and how small-scale turbulence
features influence large-scale flow behaviour.
Computer simulations, better than experiment, are able to provide detailed
insight into turbulent phenomena, at least in principle … However, the
required computer power is large, exhausting every supercomputer.
Fortunately the latter become more and more powerful, and a comparable
progress in algorithmic efficiency can be mentioned: together a factor of a
thousand per decade is gained.
The "amount" of turbulence in a flow is mainly determined by the Reynolds
number, which is a measure for the ratio between convective inertial forces
and diffusive viscous forces. Increase of the Reynolds number corresponds
with an increase of the ratio between the large an the small scales in the
flow, and hence an increase in the computational complexity of the
simulation: the latter scales with approximately the third power of the
Reynolds number.
For various industrial flows, with Reynolds numbers around tenthousand,
detailed turbulence simulations are currently possible. But the flow around
a car, for instance, has a Reynolds number of one million, and hence is a
million times more expensive. A great computational challenge for the
coming decade!
Organized by
Jaap Hollenberg
SARA NCF/NWO
Last updated on April 27th, 2000
Created by: Anne Frenkel
E-mail: annef@wins.uva.nl
