Abstracts of the scientific talks at the Inauguration of JUQUEEN

The BigBrain - Towards a Multimodal Model of the Human Brain

Speaker: Prof. Dr. med. Katrin Amunts, C. and O. Vogt-Institute of Brain Research, Universitätsklinikum Düsseldorf;
Institute for Neuroscience and Medicine, Forschungszentrum Jülich

Reference brains are indispensable tools in human brain mapping enabling integration of multimodal data into an anatomically defined standard space. Available reference brains, however, are restricted to the macroscopical scale, and do not provide information on the functionally important microscopical dimension. We push the limits of current technology by creating the first ultra-high resolution 3D- model of the human brain at nearly cellular resolution of 20 microns, based on 7,404 histological sections. The total volume of this original histological data set was 1 TByte. Major challenges for such human brain model comprise - among others - the highly folded cerebral cortex, considerable inter-subject variability, and last but not least, the pure size of the brain with its nearly 100 billion nerve cells and the same number of glial cells.

“BigBrain” is a freely available tool with unprecedented neuroanatomical insight. It allows extracting microscopic data for modeling and simulation. BigBrain enables testing of hypotheses on optimal path lengths between interconnected cortical regions, or spatial organization of genetic patterning, redefining the traditional neuroanatomy maps such as those of Brodmann and von Economo.

Making Good Use of Big Computers: High Performance Computing for Turbulent and Reactive Flows


Speaker: Prof. Dr.-Ing. Heinz Pitsch, Institute for Combustion Technology, RWTH Aachen University

Turbulent reacting flows are important in a wide range of engineering devices, including aircraft engines, automotive engines, and industrial combustors. Since the transportation sector contributes about one-third of the total greenhouse gas emissions, a reduction of these emissions is important. Predictive modeling approaches are essential in the development and optimization of novel combustion devices optimized for efficiency, stability, and pollutant emissions. However, the important features of the complex and highly non-linear interactions of turbulent flow, combustion chemistry, and multi-phase flow are not fully understood at present, partly because of the difficulties of an experimental characterization. The rapid advances in supercomputing enable Direct Numerical Simulations (DNS) as a powerful tool in combustion science, facilitating the simultaneous simulation of the pertinent multi-scale and multi-physics phenomena.

High fidelity simulations of turbulent reacting flows are computationally  very demanding, and simulations under realistic conditions still belong to the Grand Challenges of High Performance Computing (HPC). However, several examples will be shown that demonstrate how HPC can be used effectively to further enhance the understanding and to assist in the development of improved modeling approaches of combustion processes.

High-Performance Computing in Materials Science: Current Applications and Challenges


Speaker: Prof. Dr. Alexander Hartmaier, Interdisciplinary Centre for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum

“To understand whatever binds the world’s innermost core together” has always been a dream of mankind. While the theme of Dr. Faustus aims at an understanding of the metaphysical world, current research activities in computational materials science have the objective of deriving physical laws that connect the atomic structure of materials with their observable, i.e. macroscopic behavior. From quantum mechanics we know that the electronic structure of matter is responsible for its mechanical properties, like stiffness, strength, hardness, toughness. However, materials science teaches us that macroscopic material behavior – taking place on much larger length and time scales – is usually dominated by the interaction and competition of many mechanisms rather than by the occurrence of a singular one.

Hence, one primary focus of high-performance computing in materials science is to develop methods and algorithms that allow us to upscale atomistic methods such that they can unravel the complex interplay and competition of different fundamental mechanisms occurring during deformation of materials. In different examples it will be demonstrated that such upscaling requires a change of paradigm in the traditional workflow of simulations, because postprocessing of ultra-large atomistic samples of hundreds of millions of atoms becomes virtually impossible. Instead, on-the-fly-analysis tools need to be developed that allow the analysis of the physical properties of atomistic samples during the simulation.

Apart from these atomistic methods, physical descriptions of material behavior inevitably lead to the mathematical problem of solving partial differential equations for large systems. Examples will be given that show how current research in this field points into the direction of developing new efficient solvers for those mathematical problems so that full use can be made of the novel architectures of high-performance computing systems like JUQUEEN.

Simulation of Fire and Crowds - Supercomputing for Civil Security


Speaker: Prof. Dr. Armin Seyfried, Department of Computer Simulation for Fire Safety and Pedestrian Traffic, University of Wuppertal;
Jülich Supercomputing Centre, Forschungszentrum Jülich

Fire and crowd simulations are important tools for engineers to optimize the safety of complex buildings and large scale events. Two application examples are presented to emphasize how supercomputing is used to advance these tools and their underlying methods.

Within the BMBF project Hermes a decision support system during evacuation was constructed. This system constantly monitors the occupancy and escape routes. Using the present status as initial conditions, the system computes the evacuation's development. As the simulation runs faster than real time, it allows a prediction of up to 15 minutes. The calculated results can be used by the heads of operators for an optimal operation of the security personal. The test case for this evacuation assistant was the ESPRIT Arena in Düsseldorf with up to 65,000 visitors.

Fire prevention in civil engineering made a large leap forward by employing computational fluid dynamics. However, this new level of detail comes at a price: high computing resources. The needed computational power is mainly due to the multi-scale character of fire simulations, building vs. combustion length scales, which enforces a high numerical resolution. The simulation of a burning metro car and initial work on adaptive methods in fire simulations conclude the talk.