D-BAUG - Departement Bau, Umwelt und Geomatik - ETH Zürich

Highlights ▪ High-Tech Measuring Systems
Material Research on Game Consoles
First they conquered the playrooms of our chil-
dren, now they are about to change computa-
tional sciences.
by K. Kovacs, F.K. Wittel, H.J. Herrmann / IfB
Game consoles and so called Graphics Processing Units (GPUs)
from high performance graphic cards promise an extreme performance
leap for numeric simulations.Today the way we program
numerical models and run our simulations is changing
rapidly.Thereasoncanbefoundinprocessors(CPU),that require
more complicated cooling concepts due to increase in clock
frequency.To deal with this matter,frequencies were reduced in
the last years and several processors,so called multi cores were
integrated on one chip. CPUs under development will work
with up to 64 cores and graphic cards already today work with
up to512simpleprocessors that share thesamememoryonone
GPU.The theoretical increase in performance of simple integer
operationscompared tosinglecoreCPUsisup toafactorof200
at a fraction of the energy.To be able to use such processors efficiently,
software needs to be tailored to the architecture. Cell
CPUs, that are the heart of the PlayStation3, are a promising
compromise between CPUs and the cumbersome to program
GPUs.
To meet the challenges of high performance simulations on
modernsharedmemory architectures,investments infast cluster
solutions are essential.By extending our cluster to 456 cores
with a total of 1.2TB memory,a peak performance of around 5-
6 TFlops, fast 40GB/s interlink and a parallel file system with
35TB,wearenowable tomeet ourneeds.Themultitudeofchallenging
numerical approaches used to simulate building materials
was awarded recently by an “IBM Faculty Award”. With
this award,support in form of cell blade hardware and expertise
from developers is granted to facilitate the implementation
of our simulation programs to the cell blade architecture (Fig.1).
Using this technology we can expect to run significantly larger
simulationsup to10 times faster at 70% energy reductioncompared
to the newest multi-core processors.
72 ▪ D-BAUG Annual Report 2009
Rockglacier monitoring with low-cost GPS:
Case study on the Dirru glacier, Mattertal
Is it possible to detect smallest move-
ments by low-cost GPS receivers?
by P. Limpach, A. Geiger, M. Rothacher / IGP
This question shall be answered by a pilot project on the Dirru
rockglacier in the Mattertal,where a test network for GPS monitoring
has been installed in June 2009 (Fig.1a).The goal of the
test network is to investigate the potential of low-cost GPS receiversfortheprecisemonitoringofslopeinstabilitiesinmountainous
areas, in order to strengthen the understanding of
processeslinked to permafrost-related slope instabilities and to
enhance existing monitoring and early-warning systems. The
test site was selected by the Alpine Cryosphere and Geomorphology
research group of the University of Fribourg and the
Swiss Federal Office for the Environment (FOEN),based on displacements
detected by SAR interferometry and periodic GPS
surveys.This study is financially supported by FOEN.
The GPS test network consistsof three permanent GPSstations
(Fig. 2a):one reference station (REFD) outside the instable area
and twostations(DIR2 andDIR3)on the movingrockglacier.The
three stations are equipped with low-cost single-frequency (L1)
GPSreceiversbySwissmanufacturerµ-bloxandpoweredbysolar
panels (Fig. 2b).The GPS data processing is based on differential
carrier phase techniques.The low-cost GPS system provides
continuous observations of surface motions with
centimeter accuracy. It allowed to reliably observe station displacementsof2.5cm/day,whichsummedup
to3mover theobservation
period of 4 months (Fig.2c).