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Compensation of pressure peaks in PWK-type hydraulic pumps

Key Engineering Materials 2011年 490卷 33-44页

作者： Osiecki, Leszek Patrosz, Piotr Zawistowski, Tomasz Landvogt, Bettina Piechna, Janusz Zyliñski, Bartek Gdansk University of Technology ul. Narutowicza 11/12 80-233 Gdansk Poland Space Research Center Polish Academy of Sciences ul. Bartycka 18A 00-716 Warszawa Poland Fraunhofer Institute for Algorithms and Scientific Computing SCAI Schloss Birlinghoven 53754 Sankt Augustin Germany Warsaw University of Technology Pl. Politechniki 1 00-661 Warszawa Poland Bandak Engineering Postboks 1505 Ålesund Norway

Hydraulic axial pumps equipped with cam-driven commutation unit (PWK pumps) proved their high efficiency up to 55 MPa and ability to work self-sucking, even at high speed. Displacement of PWK pump may easily be changed by moving its control cam. Full discharge from hydrostatic forces makes such control possible by direct action of a low-energy actuator like proportional electromagnet or stepping motor. That eliminates heavy and costly hydraulic servomechanism, necessary in other variable displacement machines. Such a control mechanism was positively evaluated in prototype tests in Department of Hydraulics and Pneumatics of Gdañsk University of Technology. The new commutation unit generates however harmful pressure peaks. The paper presents the compensation method for pressure peaks by use of the elastic compensation chamber. It shows also results of multidisciplinary FEA and CFD analysis necessary to properly design the compensation chamber. © 2012 Trans Tech Publications, Switzerland.

关键词： Stepping motors

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Achieving an improved understanding of the factors affecting an aircraft environmental control system by coupling a 1D cabin air distribution system model with a 3D passenger cabin model using Co-simulation middleware

Achieving an improved understanding of the factors affecting...

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SAE 2009 AeroTech Congress and Exhibition

作者： Kelsall, David Ludhi, Abdul Bayrasy, Pascal Wolf, Klaus Flowmaster Ltd Fraunhofer Institute for Algorithms and Scientific Computing SCAI

Aircraft Environmental Control Systems (ECS) are designed to optimize passenger comfort by providing satisfactory cabin pressurization, and temperature and humidity control whilst minimising the risks to passenger health from airborne toxins and diseases. The paper presents a case study that investigates how the cooling load discharge from an ECS system affects the flow behaviour inside a typical mid-size, wide-body aircraft passenger cabin. The investigation uses commercial off-the-shelf one dimensional (1D) Computational Fluid Dynamics (CFD) software to model the cooling pack, cabin air distribution system, and three quarters of the passenger cabin. The centre section of the cabin is modelled using a commercial off-the-shelf three dimensional (3D) CFD package, with the co-simulation middleware providing coupling adapters to ensure that two-way, bilateral exchange of boundary parameters between the 1D and the 3D CFD models gives continuity of mass and momentum transfer. The 1D and 3D CFD applications and Co-simulation middleware are supplied by 3 independent commercial organisations. The results of the case study are discussed including the co-simulated 'velocity field of the air discharge' and the 'temperature gradient inside the cabin' within the 3D CFD model as well as the flow and temperature fields within the one-dimensional ECS cooling pack model. The paper concludes by discussing how the proper implementation of the co-simulation methods developed in this case study could bring significant benefits to engineering companies using CFD tools, including improved quality of simulation results and reduced simulation run times. Copyright © 2009 SAE International.

关键词： Computational fluid dynamics

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Life science application support in an interoperable e-science environment

Life science application support in an interoperable e-scien...

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Annual IEEE Symposium on Computer-Based Medical Systems

作者： Sonja Holl Morris Riedel Bastian Demuth Mathilde Romberg Achim Streit Vinod Kasam Forschungszentrum Juelich Juelich Supercomputing Center Juelich Germany Schloss Birlinghoven Fraunhofer Institute for Algorithms and Scientific Computing Sankt Augustin Germany

In the last decade, life science applications have become more and more integrated into e-Science environments, hence they are typically very demanding, both in terms of computational capabilities and data capacities. Especially the access to life science applications, embedded in such environments via Grid clients still constitutes a major hurdle for scientists that do not have an IT background. Life science applications often comprise a whole set of small programs instead of a single executable. Many of the graphical Grid clients are not perfectly suited for these types of applications, as they often assume that Grid jobs will run a single executable instead of a set of chained executions (i.e. sequences). This means that in order to execute a sequence of multiple programs on a single Grid resource, piping data from one program to the next, the user would have to run a hand-written shell script. Otherwise each program is independently scheduled as a Grid job, which causes unnecessary file transfers between the jobs, even if they are scheduled on the same resource. We present a generic solution to this problem and provide a reference implementation, which seamlessly integrates with the Grid middleware UNICORE. Our approach focuses on a comfortable user interface for the creation of such program sequences, validated in UNICORE-driven HPC-based Grids. Thus, we applied our approach in order to provide support for the usage of the AMBER package (a widely-used collection of programs for molecular dynamics simulations) within Grid workflows. We finally provide a scientific use case of our approach leveraging the interoperability of two different scientific infrastructures that represents an instance of the infrastructure interoperability reference model.

关键词： Middleware Biology computing Sequences Biological system modeling Bioinformatics scientific computing User interfaces Packaging Collaborative work Chemistry

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Grid Middleware and Services 2008

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2008年

作者： Domenico Talia Ramin Yahyapour Wolfgang Ziegler

ISBN: (数字)9780387784465

ISBN: (纸本)9780387784458

Grid Middleware and Services: Challenges and Solutions is the eighth volume of the CoreGRID series. The CoreGrid Proceedings is the premiere European event on Grid computing. This book aims to strengthen and advance scientific and technological excellence in the area of Grid computing. The main focus in this volume is on Grid middleware and service level agreement. Grid middleware and Grid services are two pillars of grid computing systems and applications. This book includes high-level contributions by leading researchers in both areas and presents current solutions together with future challenges. This volume includes sections on knowledge and data management on grids, Grid resource management and scheduling, Grid information, resource and workflow monitoring services, and service level agreements. Grid Middleware and Services: Challenges and Solutions is designed for a professional audience, composed of researchers and practitioners in industry. This volume is also suitable for graduate-level students in computer science.

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Grid-enabled virtual screening against malaria

Grid-enabled virtual screening against malaria

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作者： Jacq, N. Salzemann, J. Jacq, F. Legré, Y. Medernach, E. Montagnat, J. Maaß, A. Breton, V. Schwichtenberg, H. Sridhar, M. Kasam, V. Zimmermann, M. Hofmann, M. Breton, V. Laboratoire de Physique Corpusculaire Université Blaise Pascal IN2P3-CNRS UMR 6533 24 Avenue des Landais 63177 Aubière France Communication and Systèmes Grenoble France Informatique Signaux et Systèmes Université de Nice Sophia Antipolis CNRS UMR 6070 Sophia Antipolis France Department of Simulation Engineering Fraunhofer Institute for Algorithms and Scientific Computing Sankt Augustin Germany Department of Bioinformatics Fraunhofer Institute for Algorithms and Scientific Computing Sankt Augustin Germany

WISDOM is an international initiative to enable a virtual screening pipeline on a Grid infrastructure. Its first attempt was to deploy large scale in silico docking on a public Grid infrastructure. Protein-ligand docking is about computing the binding energy of a protein target to a library of potential drugs using a scoring algorithm. Previous deployments were either limited to one cluster, to Grids of clusters in the tightly protected environment of a pharmaceutical laboratory or to desktop Grids. The first large scale docking experiment ran on the EGEE Grid production service from 11 July 2005 to 19 August 2005 against targets relevant to research on malaria and saw over 41 million compounds docked for the equivalent of 80 years of CPU time. Up to 1,700 computers were simultaneously used in 15 countries around the world. Issues related to the deployment and the monitoring of the in silico docking experiment as well as experience with Grid operation and services are reported in the paper. The main problem encountered for such a large scale deployment was the Grid infrastructure stability. Although the overall success rate was above 80%, a lot of monitoring and supervision was still required at the application level to resubmit the jobs that failed. But the experiment demonstrated how Grid infrastructures have a tremendous capacity to mobilize very large CPU resources for well targeted goals during a significant period of time. This success leads to a second computing challenge targeting avian flu neuraminidase N1. © Springer Science + Business Media B.V. 2007.

关键词： Grid computing

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Reconstruction of chemical molecules from images

Reconstruction of chemical molecules from images

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29th Annual International Conference of IEEE-EMBS, Engineering in Medicine and Biology Society, EMBC'07

作者： Algorri, Maria-Elena Zimmermann, Marc Friedrich, Christoph M. Akle, Santiago Hofmann-Apitius, Martin Department of Digital Systems Instituto Tecnologico Autonomo de Mexico Mexico City Dept. of Bioinformatics Fraunhofer Institute for Algorithms and Scientific Computing Sankt Augustin Germany

ISBN: (纸本)1424407885

We have developed a system for the automatic reconstruction of chemical molecules from images. The system takes as input an electronically produced image of a chemical molecule and produces an SDF file containing the complete chemical description of the molecule. The SDF file can then be read and used by most chemical computer programs. Our system finds extensive application in information extraction problems where the molecule images contained in chemical documents need to be rendered computer readable. We have benchmarked our system against a commercially available product and have also tested it using chemical databases of several thousand images. The system can be parameterized to reconstruct images of different sources and different characteristics. © 2007 IEEE.

关键词： Image reconstruction

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Identifying gene-specific variations in biomedical text

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Journal of Bioinformatics and Computational Biology 2007年第6期5卷 1277-1296页

作者： Klinger, Roman Friedrich, Christoph M. Mevissen, Heinz Theodor Fluck, Juliane Hofmann-apitius, Martin Furlong, Laura I. Sanz, Ferran Department of Bioinformatics Fraunhofer Institute for Algorithms and Scientific Computing 53754 Sankt Augustin Schloss Birlinghoven Germany Research Unit on Biomedical Informatics (GRIB) IMIM UPF PRBB E-08003 Barcelona c/ Dr. Aiguader 88 Spain

The influence of genetic variations on diseases or cellular processes is the main focus of many investigations, and results of biomedical studies are often only accessible through scientific publications. Automatic extraction of this information requires recognition of the gene names and the accompanying allelic variant information. In a previous work, the OSIRIS system for the detection of allelic variation in text based on a query expansion approach was communicated. Challenges associated with this system are the relatively low recall for variation mentions and gene name recognition. To tackle this challenge, we integrate the ProMiner system developed for the recognition and normalization of gene and protein names with a conditional random field (CRF)-based recognition of variation terms in biomedical text. Following the newly developed normalization of variation entities, we can link textual entities to Single Nucleotide Polymorphism database (dbSNP) entries. The performance of this novel approach is evaluated, and improved results in comparison to state-of-the-art systems are reported. © 2007 Imperial College Press.

关键词： Conditional random field Named entity recognition Normalization Single nucleotide polymorphism SNP Variants

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An Automatic Multi-Level Solver Switching Strategy for PEEC-Based EMC Simulation

An Automatic Multi-Level Solver Switching Strategy for PEEC-...

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EMC Zurich 2007 - 18th International Zurich Symposium on Electromagnetic Compatibility

作者： Tanja Clees Tatiana Samrowski Martin Ludwig Zitzmann Robert Weigel Fraunhofer Institute for Algorithms and Scientific Computing Sankt Augustin Germany BMW Group Munich Germany Institute for Electronics Engineering University of Erlangen Nuremberg Erlangen Germany

In this paper, we propose a new, efficient and robust automatic solver switching strategy, called alpha-SAMG, tailored to linear systems of equations arising in PEEC-based EMC simulation. The PEEC method (partial element equivalent circuit) is an approach for transforming conducting objects into linear networks with basic electrical elements. Such equivalent circuit models can be simulated by conventional circuit solvers such as SPICE (simulation program for integrated circuit emphasis) based on the MNA (modified nodal analysis) approach. By applying appropriate sparsification techniques, sparse PEEC matrices can be obtained, adequate for iterative solvers. By using multi-level approaches, linear complexity w.r.t. time and memory consumptions can be achieved in the best case. Due to the fact that properties of PEEC matrices can differ drastically, we developed the automatic solver switching strategy alpha-SAMG. Its efficiency for PEEC matrices is demonstrated for seven practically relevant benchmark cases by comparison against standard solvers. In particular, it is shown that alpha-SAMG provides a robust and fast solution strategy.

关键词： Electromagnetic compatibility Circuit simulation Integrated circuit modeling Robustness Equivalent circuits Analytical models Sparse matrices Linear systems Equations SPICE

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Simulated Reality in Automotive Design

Simulated Reality in Automotive Design

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International Conference on Cyberworlds

作者： Andre Stork Clemens-August Thole Stanislav Klimenko Igor Nikitin Lialia Nikitina Yuri Astakhov IGD Fraunhofer Institute of Computer Graphics Research (IGD) Darmstadt Germany SCAI Fraunhofer Institute for Algorithms and Scientific Computing Darmstadt Germany ICPT Institute of Computing for Physics and Technology Moscow Russia Mathematical Institute University of Cologne Germany

In this paper we introduce Simulated Reality (SR) as a new concept for the interplay between simulation, optimization and interactive visualization. We see SR as a new metaphor for the interactive visual exploration of simulation and optimization results. The vision of Simulated Reality implies interactive behavior of simulations. Fact is today that simulations might still need hours of computation time, especially in crash worthiness. This paper shows approaches to come closer to the vision of SR. Combining design of experiments methods, metamodeling, new interpolation schemes and innovative graphics methods, we enable to user to interact with simulation parameters, optimization criteria and come to a new interpolated crash result within seconds. The approaches have been successfully applied for solution of real life car design optimization problems.

关键词： Automotive engineering Computational modeling Strontium Design optimization Visualization Computer crashes Design methodology Metamodeling Interpolation Graphics

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Reconstruction of Chemical Molecules from Images

Reconstruction of Chemical Molecules from Images

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29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS 2007), vol.11

作者： Maria-Elena Algorri Marc Zimmermann Christoph M. Friedrich Santiago Akle Martin Hofmann-Apitius Department of Digital Systems Instituto Tecnologico Autonomo de Mexico Mexicali Mexico Department of Bioinformatics Fraunhofer Institute for Algorithms and Scientific Computing Sankt Augustin Germany

关键词： Image reconstruction Optical character recognition software Data mining Chemical products Image recognition Benchmark testing System testing Image databases Image converters Character recognition

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