The ZIH colloquia is a public event and takes place at each 4th Thursday of the month at 15:00 o'clock in the room Willers-Bau A 317.
For additional or extraordinary events time and room are explicitly mentioned.

Next Colloquium

May 23, 2013: Horst Malchow (University of Osnabrueck, Institute of Environmental Systems Research): "Pattern formation in non-equilibrium systems"
The exploration of pattern formation mechanisms in nonlinear complex systems is one of the central scientific problems. The development of the theory of self-organized temporal, spatial or functional structuring of nonlinear systems far from equilibrium has been one of the milestones of structure research. The occurrence of multiple steady states and transitions from one to another after critical fluctuations, the phenomena of excitability, oscillations, waves and, in general, the emergence of macroscopic order from microscopic interactions in various nonlinear nonequilibrium systems in nature and society has required and stimulated many theoretical and, if possible, experimental studies.
Mathematical and computational modelling has turned out to be one of the useful methods to improve the understanding of such structure generating mechanisms. After a more general introduction, examples from population dynamics are presented.

Further Colloquia

June 13, 2013: additional colloquium with Scott Michael (SciApT, Indiana University): "The Power of User Statistics: Using analytics to improve service to end users"
In this talk I will present an overview of the statistics tracking system developed for use on supercomputing platforms by the Research Technologies division at Indiana University (IU). Combining and viewing statistical data from many sources including multiple compute platforms, high performance file systems, archive systems, can be a daunting task. Finding useful and actionable information in this data presents an even greater challenge. However, by aggregating data from multiple resources we have been able to gain a more comprehensive view of users activity and identify users whose workflows could be improved. In addition to describing the basic design and infrastructure of the system, I will present several use cases where we have been able to improve user experience and increase the usage efficiency of IU supercomputing resources.

September 13,2013: additional colloquium with Howard Jay Siegel, Anthony A. Maciejewski (Colorado State University)

September 26, 2013: Davi Böhme (GRS Aachen)

October 24, 2013: Sascha Hunold (TU Wien)

Past Colloquia

25. April 2013: Wolfgang Frings (FZ Jülich) "SIONlib: Scalable Massively Parallel I/O to Task-Local Files"
Parallel applications often store data in multiple task-local files, for example, to create checkpoints, to circumvent memory limitations, or to record performance data. When operating at very large processor configurations, such applications often experience scalability limitations when the simultaneous creation of thousands of files causes metadata-server contention. Furthermore, large file counts complicate the file management and operations on those files can even destabilize the file system. Even if a parallel I/O library is used and task-local files are replaced by a single shared file, new meta-data bottlenecks will be observed especially at very large scale. This talk will introduce SIONlib, a parallel I/O library that addresses also those new bottlenecks by transparently mapping a large number of task-local files onto a small number of physical files via internal metadata handling and by block alignment to ensure high performance. By discussing the design principles of SIONlib we address also the challenges that will arise on upcoming exascale systems and show how they could be solved with a software-only approach.

28. März 2013: Ulrich Kähler(DFN) "Die Authentifizierung- und Autorisierungs-Infrastruktur des Deutschen Forschungsnetzes (DFN-AAI)- - sicherer und einfacher Zugang zu geschützten Ressourcen"
Der DFN-Verein betreibt eine Authentifizierung- und Autorisierungs-Infrastruktur (DFN-AAI), um Nutzern von Einrichtungen aus Wissenschaft und Forschung (Teilnehmer) über das Wissenschaftsnetz einen Zugang zu geschützten Ressourcen (z.B. wissenschaftlichen Veröffentlichungen, lizenzpflichtiger Software, Großrechnern, GRID-Ressourcen) von Anbietern zu ermöglichen. Nutzer, die auf geschützte Ressourcen zugreifen wollen, können sich an ihrer Heimateinrichtung authentifizieren und nach Übertragung der zur Autorisierung notwendigen Daten (Attribute) Zugang zu den Ressourcen erlangen.
Der DFN-Verein koordiniert in Rücksprache mit den Teilnehmern und Anbietern die Modalitäten und Richtlinien für die Kommunikation innerhalb der DFN-AAI und passt sie dem technischen Fortschritt an.

28. Februar 2013: Andreas Dress (Bielefeld) "Modelling, Simulating and Analysing Structure Formation in Tissue and in Cellular Automata"
Structure formation has fascinated mankind ever since antiquity. And, after the introduction of infinitesimal calculus, partial differential equations appeared for a long time to constitute the only proper mathematical methodology to generate and analyse spatio-temporal models of structure formation. So, it came as a slight surprise that even rather coarse-grained and simplistic CA-type models could capture essential features of structure formation processes. In the lecture, I will first recall how we first learned about this almost 30 years ago when, jointly with Martin Gerhardt, Nils Jaeger, Peter Plath, and Heike Schuster, we tried to analyse heterocatalytic processes on metal surfaces and, this way, discovered that such processes might potentially form interesting spatial-temporal patterns -- a finding that was confirmed only later by Ronald Imbihl in a number of beautiful experiments (now in Hannover, then working at Gerhard Ertl's lab in Berlin). I will then go on to present various CA-type models that were later developed jointly with Peter Serocka at Bielefeld in the 1990s and clearly exhibited striking phase transitions in "pattern space", going e.g. from patterns of ever turning spirals to patterns of "growing, intermingling, and solidifying empires" upon one slight change of parameters for one time step, only, -- thus furnishing intriguing metaphors for the onset and establishment of e.g. cancer in healthy tissue caused (perhaps) by a slight disturbance of cell metabolism. Finally, I will turn to a mathematical analysis of certain CA dynamics and discuss some mathematical tools like discrete Fourier transforms that, as was recently shown by LIN Wei from Fudan U, can be used to treat at least some aspects of these models in proper mathematical terms.

additional colloquium at February 7, 2013, 15:00 at  WIL A317: Ivo Sbalzarini (Max-Planck-Institut für Molekulare Zellbiologie und Genetik, Zentrum für Systembiologie Dresden) - The Parallel Particle Mesh (PPM) library and a domain-specific language for particle methods
Particle methods provide a unifying framework for simulations of both discrete and continuous models. We present the PPM library, a scalable and transparent middleware for hybrid particle-mesh simulations on distributed-memory parallel computers. We discuss recent progress in hybrid multi-threading/multi-processing and adaptive-resolution simulations. In addition, we present a domain-specific language for parallel particle-mesh methods and the associated compiler and programming environment.

24. Januar 2013: Andre Brinkmann (Johannes Gutenberg-Universität Mainz) "HPC Storage: Challenges and Opportunities of new Storage Technologies" (slides)
Storage systems have been regarded as a necessary, but mostly uninteresting component of high performance computers. Several trends are currently changing this role.
First of all, the amount of data written and read from HPC storage is increasing at an incredible speed even in the domain of traditional HPC. While, e.g., checkpointing has been a common, but feasible task in mid-sized cluster environments, it becomes extremely costly and frequent in multi-petabyte installations. A second trend is that several new data centric applications from the life science and physics domain appear and that HPC is widening its realm to include these applications from the field of big data and data analytics. This new role of storage is reinforced by a widening performance gap between processors and traditional hard disks.
This talk will cover several techniques to use existing hpc storage more efficiently and to include big data solutions within an HPC center as well as approaches to include new storage technologies, like flash and phase-change memory in the HPC stack.

Past years:

History 2012
History 2011 
History 2010
History 2009
History 2008
History 1998 - 2007