@phdthesis{neeZoeckler2003, author = {(n{\´e}e Z{\"o}ckler), Malte}, title = {Efficient Visualization and Reconstruction of 3D Geometric from Neuro-Biological Confocal Microscope Scans}, year = {2003}, language = {en} } @misc{AardalHoeselKosteretal., author = {Aardal, Karen I. and Hoesel, Stan P.M. van and Koster, Arie M.C.A. and Mannino, Carlo and Sassano, Antonio}, title = {Models and Solution Techniques for Frequency Assignment Problems}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-6667}, number = {01-40}, abstract = {{\begin{rawhtml} Revised Version unter http://dx.doi.org/10.1007/s10479-007-0178-0 \end{rawhtml}} Wireless communication is used in many different situations such as mobile telephony, radio and TV broadcasting, satellite communication, and military operations. In each of these situations a frequency assignment problem arises with application specific characteristics. Researchers have developed different modelling ideas for each of the features of the problem, such as the handling of interference among radio signals, the availability of frequencies, and the optimization criterion. This survey gives an overview of the models and methods that the literature provides on the topic. We present a broad description of the practical settings in which frequency assignment is applied. We also present a classification of the different models and formulations described in the literature, such that the common features of the models are emphasized. The solution methods are divided in two parts. Optimization and lower bounding techniques on the one hand, and heuristic search techniques on the other hand. The literature is classified according to the used methods. Again, we emphasize the common features, used in the different papers. The quality of the solution methods is compared, whenever possible, on publicly available benchmark instances.}, language = {en} } @article{AbassGutscheMaesetal., author = {Abass, Aimi and Gutsche, Philipp and Maes, Bjorn and Rockstuhl, Carsten and Martins, Emiliano R}, title = {Insights into directional scattering: from coupled dipoles to asymmetric dimer nanoantennas}, series = {Opt. Express}, volume = {24}, journal = {Opt. Express}, number = {17}, doi = {10.1364/OE.24.019638}, pages = {19638 -- 19650}, abstract = {Strong and directionally specific forward scattering from optical nanoantennas is of utmost importance for various applications in the broader context of photovoltaics and integrated light sources. Here, we outline a simple yet powerful design principle to perceive a nanoantenna that provides directional scattering into a higher index substrate based on the interference of multiple electric dipoles. A structural implementation of the electric dipole distribution is possible using plasmonic nanoparticles with a fairly simple geometry, i.e. two coupled rectangular nanoparticles, forming a dimer, on top of a substrate. The key to achieve directionality is to choose a sufficiently large size for the nanoparticles. This promotes the excitation of vertical electric dipole moments due to the bi-anisotropy of the nanoantenna. In turn, asymmetric scattering is obtained by ensuring the appropriate phase relation between the vertical electric dipole moments. The scattering strength and angular spread for an optimized nanoantenna can be shown to be broadband and robust against changes in the incidence angle. The scattering directionality is maintained even for an array configuration of the dimer. It only requires the preferred scattering direction of the isolated nanoantenna not to be prohibited by interference.}, language = {en} } @article{AbbasSchneiderBollmannetal., author = {Abbas, Aennes and Schneider, Ilona and Bollmann, Anna and Funke, Jan and Oehlmann, J{\"o}rg and Prasse, Carsten and Schulte-Oehlmann, Ulrike and Seitz, Wolfram and Ternes, Thomas and Weber, Marcus and Wesely, Henning and Wagner, Martin}, title = {What you extract is what you see: Optimising the preparation of water and wastewater samples for in vitro bioassays}, series = {Water Research}, volume = {152}, journal = {Water Research}, doi = {10.1016/j.watres.2018.12.049}, pages = {47 -- 60}, abstract = {The assessment of water quality is crucial for safeguarding drinking water resources and ecosystem integrity. To this end, sample preparation and extraction is critically important, especially when investigating emerging contaminants and the toxicity of water samples. As extraction methods are rarely optimised for bioassays but rather adopted from chemical analysis, this may result in a misrepresentation of the actual toxicity. In this study, surface water, groundwater, hospital and municipal wastewater were used to characterise the impacts of common sample preparation techniques (acidification, filtration and solid phase extraction (SPE)) on the outcomes of eleven in vitro bioassays. The latter covered endocrine activity (reporter gene assays for estrogen, androgen, aryl-hydrocarbon, retinoic acid, retinoid X, vitamin D, thyroid receptor), mutagenicity (Ames fluctuation test), genotoxicity (umu test) and cytotoxicity. Water samples extracted using different SPE sorbents (Oasis HLB, Supelco ENVI-Carb+, Telos C18/ENV) at acidic and neutral pH were compared for their performance in recovering biological effects. Acidification, commonly used for stabilisation, significantly altered the endocrine activity and toxicity of most (waste)water samples. Sample filtration did not affect the majority of endpoints but in certain cases affected the (anti-)estrogenic and dioxin-like activities. SPE extracts (10.4 × final concentration), including WWTP effluents, induced significant endocrine effects that were not detected in aqueous samples (0.63 × final concentration), such as estrogenic, (anti-)androgenic and dioxin-like activities. When ranking the SPE methods using multivariate Pareto optimisation an extraction with Telos C18/ENV at pH 7 was most effective in recovering toxicity. At the same time, these extracts were highly cytotoxic masking the endpoint under investigation. Compared to that, extraction at pH 2.5 enriched less cytotoxicity. In summary, our study demonstrates that sample preparation and extraction critically affect the outcome of bioassays when assessing the toxicity of water samples. Depending on the water matrix and the bioassay, these methods need to be optimised to accurately assess water quality.}, language = {en} } @book{AbbinkBaermannBešinovicetal., author = {Abbink, Erwin and B{\"a}rmann, Andreas and Bešinovic, Nikola and Bohlin, Markus and Cacchiani, Valentina and Caimi, Gabrio and de Fabris, Stefano and Dollevoet, Twan and Fischer, Frank and F{\"u}genschuh, Armin and Galli, Laura and Goverde, Rob M.P. and Hansmann, Ronny and Homfeld, Henning and Huisman, Dennis and Johann, Marc and Klug, Torsten and T{\"o}rnquist Krasemann, Johanna and Kroon, Leo and Lamorgese, Leonardo and Liers, Frauke and Mannino, Carlo and Medeossi, Giorgio and Pacciarelli, Dario and Reuther, Markus and Schlechte, Thomas and Schmidt, Marie and Sch{\"o}bel, Anita and Sch{\"u}lldorf, Hanno and Stieber, Anke and Stiller, Sebastian and Toth, Paolo and Zimmermann, Uwe}, title = {Handbook of Optimization in the Railway Industry}, volume = {268}, editor = {Bornd{\"o}rfer, Ralf and Klug, Torsten and Lamorgese, Leonardo and Mannino, Carlo and Reuther, Markus and Schlechte, Thomas}, publisher = {Springer Verlag}, isbn = {978-3-319-72152-1}, doi = {10.1007/978-3-319-72153-8}, abstract = {This book promotes the use of mathematical optimization and operations research methods in rail transportation. The editors assembled thirteen contributions from leading scholars to present a unified voice, standardize terminology, and assess the state-of-the-art. There are three main clusters of articles, corresponding to the classical stages of the planning process: strategic, tactical, and operational. These three clusters are further subdivided into five parts which correspond to the main phases of the railway network planning process: network assessment, capacity planning, timetabling, resource planning, and operational planning. Individual chapters cover: Simulation Capacity Assessment Network Design Train Routing Robust Timetabling Event Scheduling Track Allocation Blocking Shunting Rolling Stock Crew Scheduling Dispatching Delay Propagation}, language = {en} } @article{AbbottStraubeAartsetal., author = {Abbott, Joshua L. and Straube, Arthur and Aarts, Dirk G. A. L. and Dullens, Roel P. A.}, title = {Transport of a colloidal particle driven across a temporally oscillating optical potential energy landscape}, series = {New J. Phys.}, volume = {21}, journal = {New J. Phys.}, doi = {10.1088/1367-2630/ab3765}, pages = {083027}, abstract = {A colloidal particle is driven across a temporally oscillating one-dimensional optical potential energy landscape and its particle motion is analysed. Different modes of dynamic mode locking are observed and are confirmed with the use of phase portraits. The effect of the oscillation frequency on the mode locked step width is addressed and the results are discussed in light of a high-frequency theory and compared to simulations. Furthermore, the influence of the coupling between the particle and the optical landscape on mode locking is probed by increasing the maximum depth of the optical landscape. Stronger coupling is seen to increase the width of mode locked steps. Finally, transport across the temporally oscillating landscape is studied by measuring the effective diffusion coefficient of a mobile particle, which is seen to be highly sensitive to the driving velocity and mode locking.}, language = {en} } @misc{AbboudGroetschelKoch, author = {Abboud, Nadine and Gr{\"o}tschel, Martin and Koch, Thorsten}, title = {Mathematical Methods for Physical Layout of Printed Circuit Boards: An Overview}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-9231}, number = {06-29}, abstract = {This article surveys mathematical models and methods used for physical PCB layout, i.e., component placement and wire routing. The main concepts are briefly described together with relevant references.}, language = {en} } @article{AbboudGroetschelKoch2008, author = {Abboud, Nadine and Gr{\"o}tschel, Martin and Koch, Thorsten}, title = {Mathematical methods for physical layout of printed circuit boards: an overview}, series = {OR Spectrum}, volume = {30}, journal = {OR Spectrum}, number = {3}, doi = {10.1007/s00291-007-0080-9}, pages = {453 -- 468}, year = {2008}, language = {en} } @misc{AbdelHamidAscheuerGroetschel, author = {Abdel-Hamid, Atef Abdel-Aziz and Ascheuer, Norbert and Gr{\"o}tschel, Martin}, title = {Order Picking in an Automatic Warehouse: Solving Online Asymmetric TSPs}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-3519}, number = {SC-98-08}, abstract = {We report on a joint project with industry that had the aim to sequence transportation requests within an automatic storage system in such a way that the overall travel time is minimized. The manufacturing environment is such that scheduling decisions have to be made before all jobs are known. We have modeled this task as an \emph{online} Asymmetric Traveling Salesman Problem (ATSP). Several heuristics for the online ATSP are compared computationally within a simulation environment to judge which should be used in practice. Compared to the priority rule used so far, the optimization package reduced the unloaded travel time by about 40~\\%. Because of these significant savings our procedure was implemented as part of the control software for the stacker cranes of the storage systems.}, language = {en} } @misc{AbdelHamidAscheuerGroetscheletal., author = {Abdel-Hamid, Atef Abdel-Aziz and Ascheuer, Norbert and Gr{\"o}tschel, Martin and Schorer, Herbert}, title = {Simulation und Optimierung einer PC-Fertigung unter Echtzeitbedingungen}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-1700}, number = {SC-95-04}, abstract = {Die Business Unit PC in Augsburg ist die zentrale Produktionsst{\"a}tte der Siemens--Nixdorf Informationssysteme (SNI) AG f{\"u}r Personal Computer sowie f{\"u}r einige Periph{\"a}rger{\"a}te. Das Werk, entworfen nach modernen CIM/CAI--Konzepten (Computer Integrated Manufacturing/ Computer Aided Industry), wurde 1987 errichtet. Bald zeigte sich jedoch, daß es f{\"u}r ein zu geringes Produktionsvolumen ausgelegt war und einige Komponenten des Systems Engp{\"a}sse im Produktionsbetrieb darstellen. Das Management suchte nach M{\"o}glichkeiten, den Produktionsfluß zu verbessern, ohne teure technische {\"A}nderungen am System vornehmen zu m{\"u}ssen. Eine Forschungsgruppe des Konrad--Zuse--Zentrums f{\"u}r Informationstechnik (die ehemals an der Universit{\"a}t Augsburg ans{\"a}ssig war) analysierte, unterst{\"u}tzt von einigen Studenten und Ingenieuren der SNI, den Produktionsfluß und lokalisierte Schwachstellen. Basierend auf diesen Erkenntnissen wurden mathematische Fragestellungen erarbeitet und auf mathematischen Optimierungsverfahren basierende Softwarepakete entwickelt, die jetzt teilweise bei SNI im Einsatz sind. Im folgenden werden einige dieser Fragestellungen, deren Modellierung und mathematische Behandlung beschrieben. Einige der Ans{\"a}tze, die hier dargestellt werden sollen, sind teilweise schon in Gr{\"o}tschel [Gr{\"o}92] angesprochen worden.}, language = {de} } @inproceedings{AbdelHamidAscheuerGroetscheletal.1995, author = {Abdel-Hamid, Atef Abdel-Aziz and Ascheuer, Norbert and Gr{\"o}tschel, Martin and Schorer, Herbert}, title = {Simulation und Optimierung einer PC-Fertigung unter Echtzeitbedingungen}, series = {Mathematik in der Praxis. Fallstudien aus Industrie, Wirtschaft, Naturwissenschaften und Medizin}, booktitle = {Mathematik in der Praxis. Fallstudien aus Industrie, Wirtschaft, Naturwissenschaften und Medizin}, editor = {Bachem, Achim and J{\"u}nger, Michael and Schrader, Rainer}, publisher = {Springer}, pages = {261 -- 277}, year = {1995}, language = {en} } @misc{AbdelHamidBorndoerfer, author = {Abdel-Hamid, Atef Abdel-Aziz and Bornd{\"o}rfer, Ralf}, title = {On the Complexity of Storage Assignment Problems.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-1430}, number = {SC-94-14}, abstract = {{\def\NP{\hbox{\$\cal N\kern-.1667em\cal P\$}} The {\sl storage assignment problem} asks for the cost minimal assignment of containers with different sizes to storage locations with different capacities. Such problems arise, for instance, in the optimal control of automatic storage devices in flexible manufacturing systems. This problem is known to be \$\NP\$-hard in the strong sense. We show that the storage assignment problem is \$\NP\$-hard for {\sl bounded sizes and capacities}, even if the sizes have values \$1\$ and~\$2\$ and the capacities value~\$2\$ only, a case we encountered in practice. Moreover, we prove that no polynomial time \$\epsilon\$-approximation algorithm exists. This means that almost all storage assignment problems arising in practice are indeed hard.}}, language = {en} } @article{AbebeAbassGomardetal., author = {Abebe, Muluneh G. and Abass, Aimi and Gomard, Guillaume and Zschiedrich, Lin and Lemmer, Uli and Richards, Bryce S. and Rockstuhl, Carsten and Paetzold, Ulrich W.}, title = {Rigorous wave-optical treatment of photon recycling in thermodynamics of photovoltaics: Perovskite thin-film solar cells}, series = {Phys. Rev. B}, volume = {98}, journal = {Phys. Rev. B}, doi = {10.1103/PhysRevB.98.075141}, pages = {075141}, language = {en} } @inproceedings{AbebeGomardZschiedrichetal., author = {Abebe, Muluneh G. and Gomard, Guillaume and Zschiedrich, Lin and Rockstuhl, Carsten and Paetzold, Ulrich W. and Abass, Aimi}, title = {Thermodynamics of Photon Recycling in Four Terminal Perovskite/si Tandem Solar Cells}, series = {Optical Nanostructures and Advanced Materials for Photovoltaics}, booktitle = {Optical Nanostructures and Advanced Materials for Photovoltaics}, doi = {10.1364/PV.2017.PM4A.2}, pages = {PM4A.2}, language = {en} } @article{AbendrothBujotzekShanetal.2011, author = {Abendroth, Frank and Bujotzek, Alexander and Shan, Min and Haag, Rainer and Weber, Marcus and Seitz, Oliver}, title = {DNA-controlled bivalent presentation of ligands for the estrogen receptor}, series = {Angew. Chem. Int. Ed.}, journal = {Angew. Chem. Int. Ed.}, year = {2011}, language = {en} } @article{AbendrothSollederWelkeretal., author = {Abendroth, Frank and Solleder, Marthe and Welker, Pia and Licha, Kai and Weber, Marcus and Seitz, Oliver and Mangoldt, Dorothea}, title = {High affinity flourescence labelled ligands for the estrogen receptor}, series = {Eur. J. Org. Chem.}, volume = {2015}, journal = {Eur. J. Org. Chem.}, number = {10}, pages = {2157 -- 2166}, language = {en} } @article{AblyazimovAbuhozaAdaketal., author = {Ablyazimov, T. and Abuhoza, A. and Adak, R. P. and Reinefeld, Alexander and Schintke, Florian and et al.,}, title = {Challenges in QCD matter physics - The scientific programme of the Compressed Baryonic Matter experiment at FAIR}, series = {The European Physical Journal A}, journal = {The European Physical Journal A}, doi = {10.1140/epja/i2017-12248-y}, language = {en} } @misc{AboulhassanBaumWodoetal., author = {Aboulhassan, Amal and Baum, Daniel and Wodo, Olga and Ganapathysubramanian, Baskar and Amassian, Aram and Hadwiger, Markus}, title = {A Novel Framework for Visual Detection and Exploration of Performance Bottlenecks in Organic Photovoltaic Solar Cell Materials}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-54353}, abstract = {Current characterization methods of the so-called Bulk Heterojunction (BHJ), which is the main material of Organic Photovoltaic (OPV) solar cells, are limited to the analysis of global fabrication parameters. This reduces the efficiency of the BHJ design process, since it misses critical information about the local performance bottlenecks in the morphology of the material. In this paper, we propose a novel framework that fills this gap through visual characterization and exploration of local structure-performance correlations. We also propose a formula that correlates the structural features with the performance bottlenecks. Since research into BHJ materials is highly multidisciplinary, our framework enables a visual feedback strategy that allows scientists to build intuition about the best choices of fabrication parameters. We evaluate the usefulness of our proposed system by obtaining new BHJ characterizations. Furthermore, we show that our approach could substantially reduce the turnaround time.}, language = {en} } @article{AboulhassanBaumWodoetal., author = {Aboulhassan, Amal and Baum, Daniel and Wodo, Olga and Ganapathysubramanian, Baskar and Amassian, Aram and Hadwiger, Markus}, title = {A Novel Framework for Visual Detection and Exploration of Performance Bottlenecks in Organic Photovoltaic Solar Cell Materials}, series = {Computer Graphics Forum}, volume = {34}, journal = {Computer Graphics Forum}, number = {3}, publisher = {Wiley}, doi = {10.1111/cgf.12652}, pages = {401 -- 410}, abstract = {The current characterization methods of the Bulk Heterojunction (BHJ) - the main material of the new Organic Photovoltaic solar cells - are limited to the analysis of global fabrication parameters. This reduces the efficiency of the BHJ design process, since it misses critical information about the local performance bottlenecks in the morphology of the material. In this paper, we propose a novel framework that fills this gap through visual charac- terization and exploration of local structure-performance correlations. We propose a new formula that correlates the structural features to the performance bottlenecks. Since research into BHJ materials is highly multidisci- plinary, we enable a visual feedback strategy that allows the scientists to build intuition about the best choices of fabrication parameters. We evaluate the usefulness of our proposed system by obtaining new BHJ characteri- zations. We furthermore show that our approach could reduce the previous work-flow time from days to minutes.}, language = {en} } @misc{AboulhassanSicatBaumetal., author = {Aboulhassan, Amal and Sicat, Ronell and Baum, Daniel and Wodo, Olga and Hadwiger, Markus}, title = {Comparative Visual Analysis of Structure-Performance Relations in Complex Bulk-Heterojunction Morphologies}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-63239}, abstract = {The structure of Bulk-Heterojunction (BHJ) materials, the main component of organic photovoltaic solar cells, is very complex, and the relationship between structure and performance is still largely an open question. Overall, there is a wide spectrum of fabrication configurations resulting in different BHJ morphologies and correspondingly different performances. Current state- of-the-art methods for assessing the performance of BHJ morphologies are either based on global quantification of morphological features or simply on visual inspection of the morphology based on experimental imaging. This makes finding optimal BHJ structures very challenging. Moreover, finding the optimal fabrication parameters to get an optimal structure is still an open question. In this paper, we propose a visual analysis framework to help answer these questions through comparative visualization and parameter space exploration for local morphology features. With our approach, we enable scientists to explore multivariate correlations between local features and performance indicators of BHJ morphologies. Our framework is built on shape-based clustering of local cubical regions of the morphology that we call patches. This enables correlating the features of clusters with intuition-based performance indicators computed from geometrical and topological features of charge paths.}, language = {en} } @article{AboulhassanSicatBaumetal., author = {Aboulhassan, Amal and Sicat, Ronell and Baum, Daniel and Wodo, Olga and Hadwiger, Markus}, title = {Comparative Visual Analysis of Structure-Performance Relations in Complex Bulk-Heterojunction Morphologies}, series = {Computer Graphics Forum}, volume = {36}, journal = {Computer Graphics Forum}, number = {3}, publisher = {Wiley}, doi = {10.1111/cgf.13191}, pages = {329 -- 339}, abstract = {The structure of Bulk-Heterojunction (BHJ) materials, the main component of organic photovoltaic solar cells, is very complex, and the relationship between structure and performance is still largely an open question. Overall, there is a wide spectrum of fabrication configurations resulting in different BHJ morphologies and correspondingly different performances. Current state- of-the-art methods for assessing the performance of BHJ morphologies are either based on global quantification of morphological features or simply on visual inspection of the morphology based on experimental imaging. This makes finding optimal BHJ structures very challenging. Moreover, finding the optimal fabrication parameters to get an optimal structure is still an open question. In this paper, we propose a visual analysis framework to help answer these questions through comparative visualization and parameter space exploration for local morphology features. With our approach, we enable scientists to explore multivariate correlations between local features and performance indicators of BHJ morphologies. Our framework is built on shape-based clustering of local cubical regions of the morphology that we call patches. This enables correlating the features of clusters with intuition-based performance indicators computed from geometrical and topological features of charge paths.}, language = {en} } @misc{Achterberg, author = {Achterberg, Tobias}, title = {SCIP - a framework to integrate Constraint and Mixed Integer Programming}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-7947}, number = {04-19}, abstract = {Constraint Programs and Mixed Integer Programs are closely related optimization problems originating from different scientific areas. Today's state-of-the-art algorithms of both fields have several strategies in common, in particular the branch-and-bound process to recursively divide the problem into smaller sub problems. On the other hand, the main techniques to process each sub problem are different, and it was observed that they have complementary strenghts. We propose a programming framework {\sffamily SCIP} that integrates techniques from both fields in order to exploit the strenghts of both, Constraint Programming and Mixed Integer Programming. In contrast to other proposals of recent years to combine both fields, {\sffamily SCIP} does not focus on easy implementation and rapid prototyping, but is tailored towards expert users in need of full, in-depth control and high performance.}, language = {en} } @phdthesis{Achterberg, author = {Achterberg, Tobias}, title = {Constraint Integer Programming}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-11129}, abstract = {This thesis introduces the novel paradigm of "constraint integer programming" (CIP), which integrates constraint programming (CP) and mixed integer programming (MIP) modeling and solving techniques. It is supplemented by the software SCIP, which is a solver and framework for constraint integer programming that also features SAT solving techniques. SCIP is freely available in source code for academic and non-commercial purposes. Our constraint integer programming approach is a generalization of MIP that allows for the inclusion of arbitrary constraints, as long as they turn into linear constraints on the continuous variables after all integer variables have been fixed. The constraints, may they be linear or more complex, are treated by any combination of CP and MIP techniques: the propagation of the domains by constraint specific algorithms, the generation of a linear relaxation and its solving by LP methods, and the strengthening of the LP by cutting plane separation. The current version of SCIP comes with all of the necessary components to solve mixed integer programs. In the thesis, we cover most of these ingredients and present extensive computational results to compare different variants for the individual building blocks of a MIP solver. We focus on the algorithms and their impact on the overall performance of the solver. In addition to mixed integer programming, the thesis deals with chip design verification, which is an important topic of electronic design automation. Chip manufacturers have to make sure that the logic design of a circuit conforms to the specification of the chip. Otherwise, the chip would show an erroneous behavior that may cause failures in the device where it is employed. An important subproblem of chip design verification is the property checking problem, which is to verify whether a circuit satisfies a specified property. We show how this problem can be modeled as constraint integer program and provide a number of problem-specific algorithms that exploit the structure of the individual constraints and the circuit as a whole. Another set of extensive computational benchmarks compares our CIP approach to the current state-of-the-art SAT methodology and documents the success of our method.}, language = {en} } @phdthesis{Achterberg, author = {Achterberg, Tobias}, title = {Constraint Integer Programming}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:83-opus-16117}, abstract = {This thesis introduces the novel paradigm of constraint integer programming (CIP), which integrates constraint programming (CP) and mixed integer programming (MIP) modeling and solving techniques. It is supplemented by the software SCIP, which is a solver and framework for constraint integer programming that also features SAT solving techniques. SCIP is freely available in source code for academic and non-commercial purposes. Our constraint integer programming approach is a generalization of MIP that allows for the inclusion of arbitrary constraints, as long as they turn into linear constraints on the continuous variables after all integer variables have been fixed. The constraints, may they be linear or more complex, are treated by any combination of CP and MIP techniques: the propagation of the domains by constraint specific algorithms, the generation of a linear relaxation and its solving by LP methods, and the strengthening of the LP by cutting plane separation. The current version of SCIP comes with all of the necessary components to solve mixed integer programs. In the thesis, we cover most of these ingredients and present extensive computational results to compare different variants for the individual building blocks of a MIP solver. We focus on the algorithms and their impact on the overall performance of the solver. In addition to mixed integer programming, the thesis deals with chip design verification, which is an important topic of electronic design automation. Chip manufacturers have to make sure that the logic design of a circuit conforms to the specification of the chip. Otherwise, the chip would show an erroneous behavior that may cause failures in the device where it is employed. An important subproblem of chip design verification is the property checking problem, which is to verify whether a circuit satisfies a specified property. We show how this problem can be modeled as constraint integer program and provide a number of problem-specific algorithms that exploit the structure of the individual constraints and the circuit as a whole. Another set of extensive computational benchmarks compares our CIP approach to the current state-of-the-art SAT methodology and documents the success of our method.}, language = {en} } @misc{Achterberg, author = {Achterberg, Tobias}, title = {Conflict Analysis in Mixed Integer Programming}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-8537}, number = {05-19}, abstract = {Conflict analysis for infeasible subproblems is one of the key ingredients in modern SAT solvers to cope with large real-world instances. In contrast, it is common practice for today's mixed integer programming solvers to just discard infeasible subproblems and the information they reveal. In this paper we try to remedy this situation by generalizing the SAT infeasibility analysis to mixed integer programming. We present heuristics for branch-and-cut solvers to generate valid inequalities from the current infeasible subproblem and the associated branching information. SAT techniques can then be used to strengthen the resulting cuts. We performed computational experiments which show the potential of our method: On feasible MIP instances, the number of required branching nodes was reduced by 50\\% in the geometric mean. However, the total solving time increased by 15\\%. on infeasible MIPs arising in the context of chip verification, the number of nodes was reduced by 90\\%, thereby reducing the solving time by 60\\%.}, language = {en} } @misc{AchterbergBerthold, author = {Achterberg, Tobias and Berthold, Timo}, title = {Improving the Feasibility Pump}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-8754}, number = {05-42}, abstract = {The Feasibility Pump of Fischetti, Glover, Lodi, and Bertacco has proved to be a very successful heuristic for finding feasible solutions of mixed integer programs. The quality of the solutions in terms of the objective value, however, tends to be poor. This paper proposes a slight modification of the algorithm in order to find better solutions. Extensive computational results show the success of this variant: in 89 out of 121 MIP instances the modified version produces improved solutions in comparison to the original Feasibility Pump.}, language = {en} } @article{AchterbergBerthold2007, author = {Achterberg, Tobias and Berthold, Timo}, title = {Improving the Feasibility Pump}, series = {Discrete Optimization}, volume = {Special Issue 4}, journal = {Discrete Optimization}, number = {1}, pages = {77 -- 86}, year = {2007}, language = {en} } @inproceedings{AchterbergBerthold2009, author = {Achterberg, Tobias and Berthold, Timo}, title = {Hybrid Branching}, series = {Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems, 6th International Conference, CPAIOR 2009}, volume = {5547}, booktitle = {Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems, 6th International Conference, CPAIOR 2009}, editor = {van Hoeve, Willem and Hooker, John}, publisher = {Springer}, pages = {309 -- 311}, year = {2009}, language = {en} } @misc{AchterbergBertholdHeinzetal., author = {Achterberg, Tobias and Berthold, Timo and Heinz, Stefan and Koch, Thorsten and Wolter, Kati}, title = {Constraint Integer Programming: Techniques and Applications}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-10950}, number = {08-43}, abstract = {This article introduces constraint integer programming (CIP), which is a novel way to combine constraint programming (CP) and mixed integer programming (MIP) methodologies. CIP is a generalization of MIP that supports the notion of general constraints as in CP. This approach is supported by the CIP framework SCIP, which also integrates techniques for solving satisfiability problems. SCIP is available in source code and free for noncommercial use. We demonstrate the usefulness of CIP on three tasks. First, we apply the constraint integer programming approach to pure mixed integer programs. Computational experiments show that SCIP is almost competitive to current state-of-the-art commercial MIP solvers. Second, we demonstrate how to use CIP techniques to compute the number of optimal solutions of integer programs. Third, we employ the CIP framework to solve chip design verification problems, which involve some highly nonlinear constraint types that are very hard to handle by pure MIP solvers. The CIP approach is very effective here: it can apply the full sophisticated MIP machinery to the linear part of the problem, while dealing with the nonlinear constraints by employing constraint programming techniques.}, language = {en} } @misc{AchterbergBertholdHendel, author = {Achterberg, Tobias and Berthold, Timo and Hendel, Gregor}, title = {Rounding and Propagation Heuristics for Mixed Integer Programming}, doi = {10.1007/978-3-642-29210-1_12}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-13255}, number = {11-29}, abstract = {Primal heuristics are an important component of state-of-the-art codes for mixed integer programming. In this paper, we focus on primal heuristics that only employ computationally inexpensive procedures such as rounding and logical deductions (propagation). We give an overview of eight different approaches. To assess the impact of these primal heuristics on the ability to find feasible solutions, in particular early during search, we introduce a new performance measure, the primal integral. Computational experiments evaluate this and other measures on MIPLIB~2010 benchmark instances.}, language = {en} } @misc{AchterbergBertholdKochetal., author = {Achterberg, Tobias and Berthold, Timo and Koch, Thorsten and Wolter, Kati}, title = {Constraint Integer Programming: a New Approach to Integrate CP and MIP}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-10520}, number = {08-01}, abstract = {This article introduces constraint integer programming (CIP), which is a novel way to combine constraint programming (CP) and mixed integer programming (MIP) methodologies. CIP is a generalization of MIP that supports the notion of general constraints as in CP. This approach is supported by the CIP framework SCIP, which also integrates techniques from SAT solving. SCIP is available in source code and free for non-commercial use. We demonstrate the usefulness of CIP on two tasks. First, we apply the constraint integer programming approach to pure mixed integer programs. Computational experiments show that SCIP is almost competitive to current state-of-the-art commercial MIP solvers. Second, we employ the CIP framework to solve chip design verification problems, which involve some highly non-linear constraint types that are very hard to handle by pure MIP solvers. The CIP approach is very effective here: it can apply the full sophisticated MIP machinery to the linear part of the problem, while dealing with the non-linear constraints by employing constraint programming techniques.}, language = {en} } @inproceedings{AchterbergBertholdKochetal.2008, author = {Achterberg, Tobias and Berthold, Timo and Koch, Thorsten and Wolter, Kati}, title = {Constraint Integer Programming: A New Approach to Integrate CP and MIP}, series = {Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems, 5th International Conference, CPAIOR 2008}, volume = {5015}, booktitle = {Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems, 5th International Conference, CPAIOR 2008}, editor = {Perron, Laurent and Trick, Michael}, publisher = {Springer}, doi = {10.1007/978-3-540-68155-7_4}, pages = {6 -- 20}, year = {2008}, language = {en} } @article{AchterbergBixbyGuetal., author = {Achterberg, Tobias and Bixby, Robert E. and Gu, Zonghao and Rothberg, Edward and Weninger, Dieter}, title = {Presolve Reductions in Mixed Integer Programming}, series = {INFORMS Journal on Computing}, journal = {INFORMS Journal on Computing}, abstract = {Mixed integer programming has become a very powerful tool for modeling and solving real-world planning and scheduling problems, with the breadth of applications appearing to be almost unlimited. A critical component in the solution of these mixed-integer programs is a set of routines commonly referred to as presolve. Presolve can be viewed as a collection of preprocessing techniques that reduce the size of and, more importantly, improve the ``strength'' of the given model formulation, that is, the degree to which the constraints of the formulation accurately describe the underlying polyhedron of integer-feasible solutions. As our computational results will show, presolve is a key factor in the speed with which we can solve mixed-integer programs, and is often the difference between a model being intractable and solvable, in some cases easily solvable. In this paper we describe the presolve functionality in the Gurobi commercial mixed-integer programming code. This includes an overview, or taxonomy of the different methods that are employed, as well as more-detailed descriptions of several of the techniques, with some of them appearing, to our knowledge, for the first time in the literature.}, language = {en} } @misc{AchterbergBixbyGuetal., author = {Achterberg, Tobias and Bixby, Robert E. and Gu, Zonghao and Rothberg, Edward and Weninger, Dieter}, title = {Presolve Reductions in Mixed Integer Programming}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-60370}, abstract = {Mixed integer programming has become a very powerful tool for modeling and solving real-world planning and scheduling problems, with the breadth of applications appearing to be almost unlimited. A critical component in the solution of these mixed-integer programs is a set of routines commonly referred to as presolve. Presolve can be viewed as a collection of preprocessing techniques that reduce the size of and, more importantly, improve the ``strength'' of the given model formulation, that is, the degree to which the constraints of the formulation accurately describe the underlying polyhedron of integer-feasible solutions. As our computational results will show, presolve is a key factor in the speed with which we can solve mixed-integer programs, and is often the difference between a model being intractable and solvable, in some cases easily solvable. In this paper we describe the presolve functionality in the Gurobi commercial mixed-integer programming code. This includes an overview, or taxonomy of the different methods that are employed, as well as more-detailed descriptions of several of the techniques, with some of them appearing, to our knowledge, for the first time in the literature.}, language = {en} } @misc{AchterbergBrinkmannWedler, author = {Achterberg, Tobias and Brinkmann, Raik and Wedler, Markus}, title = {Property Checking with Constraint Integer Programming}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-10376}, number = {07-37}, abstract = {We address the property checking problem for SoC design verification at the register transfer level (RTL) by integrating techniques from integer programming, constraint programming, and SAT solving. Specialized domain propagation and preprocessing algorithms for individual RTL operations extend a general constraint integer programming framework. Conflict clauses are learned by analyzing infeasible LPs and deductions, and by employing reverse propagation. Experimental results show that our approach outperforms SAT techniques for proving the validity of properties on circuits containing arithmetics.}, language = {en} } @misc{AchterbergGroetschelKoch, author = {Achterberg, Tobias and Gr{\"o}tschel, Martin and Koch, Thorsten}, title = {Software for Teaching Modeling of Integer Programming Problems}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-9176}, number = {06-23}, abstract = {Modern applications of mathematical programming must take into account a multitude of technical details, business demands, and legal requirements. Teaching the mathematical modeling of such issues and their interrelations requires real-world examples that are well beyond the toy sizes that can be tackled with the student editions of most commercial software packages. We present a new tool, which is freely available for academic use including complete source code. It consists of an algebraic modeling language and a linear mixed integer programming solver. The performance and features of the tool are in the range of current state-of-the-art commercial tools, though not in all aspects as good as the best ones. Our tool does allow the execution and analysis of large real-world instances in the classroom and can therefore enhance the teaching of problem solving issues. Teaching experience has been gathered and practical usability was tested in classes at several universities and a two week intensive block course at TU Berlin. The feedback from students and teachers has been very positive.}, language = {en} } @article{AchterbergGroetschelKoch2006, author = {Achterberg, Tobias and Gr{\"o}tschel, Martin and Koch, Thorsten}, title = {Teaching MIP Modeling and Solving}, series = {OR/MS Today}, volume = {33}, journal = {OR/MS Today}, number = {6}, pages = {14 -- 15}, year = {2006}, language = {en} } @misc{AchterbergHeinzKoch, author = {Achterberg, Tobias and Heinz, Stefan and Koch, Thorsten}, title = {Counting solutions of integer programs using unrestricted subtree detection}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-10632}, number = {08-09}, abstract = {In the recent years there has been tremendous progress in the development of algorithms to find optimal solutions for integer programs. In many applications it is, however, desirable (or even necessary) to generate all feasible solutions. Examples arise in the areas of hardware and software verification and discrete geometry. In this paper, we investigate how to extend branch-and-cut integer programming frameworks to support the generation of all solutions. We propose a method to detect so-called unrestricted subtrees, which allows us to prune the integer program search tree and to collect several solutions simultaneously. We present computational results of this branch-and-count paradigm which show the potential of the unrestricted subtree detection.}, language = {en} } @inproceedings{AchterbergHeinzKoch2008, author = {Achterberg, Tobias and Heinz, Stefan and Koch, Thorsten}, title = {Counting Solutions of Integer Programs Using Unrestricted Subtree Detection}, series = {Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems, 5th International Conference, CPAIOR 2008}, volume = {5015}, booktitle = {Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems, 5th International Conference, CPAIOR 2008}, editor = {Perron, Laurent and Trick, Michael}, publisher = {Springer}, pages = {278 -- 282}, year = {2008}, language = {en} } @misc{AchterbergKochMartin, author = {Achterberg, Tobias and Koch, Thorsten and Martin, Alexander}, title = {Branching on History Information}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-6990}, number = {02-32}, abstract = {Mixed integer programs (\$MIPs\$) are commonly solved with branch and bound algorithms based on linear programming. The success and the speed of the algorithm strongly depends on the strategy used to select the branching variables. Today's state-of-the-art strategy is called \emph{pseudocost branching} and uses information of previous branchings to determine the current branching. We propose a modification of \emph{pseudocost branching} which we call \emph{history branching}. This strategy has been implemented in \$SIP\$, a state-of-the-art \$MIP\$ solver. We give computational results that show the superiority of the new strategy.}, language = {en} } @misc{AchterbergKochMartin, author = {Achterberg, Tobias and Koch, Thorsten and Martin, Alexander}, title = {Branching rules revisited}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-7886}, number = {04-13}, abstract = {Mixed integer programs are commonly solved with linear programming based branch-and-bound algorithms. The success of the algorithm strongly depends on the strategy used to select the variable to branch on. We present a new generalization called {\sl reliability branching} of today's state-of-the-art {\sl strong branching} and {\sl pseudocost branching} strategies for linear programming based branch-and-bound algorithms. After reviewing commonly used branching strategies and performing extensive computational studies we compare different parameter settings and show the superiority of our proposed newstrategy.}, language = {en} } @misc{AchterbergKochMartin, author = {Achterberg, Tobias and Koch, Thorsten and Martin, Alexander}, title = {MIPLIB 2003}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-8625}, number = {05-28}, abstract = {This paper reports on the fourth version of the Mixed Integer Programming Library. Since ({\sc miplib}) is to provide a concise set of challenging problems, it became necessary to purge instances that became too easy. We present an overview of the 27 new problems and statistical data for all 60 instances.}, language = {en} } @article{AchterbergKochMartin2005, author = {Achterberg, Tobias and Koch, Thorsten and Martin, Alexander}, title = {Branching Rules Revisited}, series = {Operations Research Letters}, volume = {33}, journal = {Operations Research Letters}, number = {1}, publisher = {Elsevier / North-Holland}, doi = {10.1016/j.orl.2004.04.002}, pages = {42 -- 54}, year = {2005}, language = {en} } @article{AchterbergKochMartin2006, author = {Achterberg, Tobias and Koch, Thorsten and Martin, Alexander}, title = {MIPLIB 2003}, series = {Operations Research Letters}, volume = {34}, journal = {Operations Research Letters}, number = {4}, publisher = {Elsevier / North-Holland}, doi = {10.1016/j.orl.2005.07.009}, pages = {361 -- 372}, year = {2006}, language = {en} } @misc{AchterbergKochTuchscherer, author = {Achterberg, Tobias and Koch, Thorsten and Tuchscherer, Andreas}, title = {On the Effects of Minor Changes in Model Formulations}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-10808}, number = {08-29}, abstract = {Starting with the description of the Traveling Salesmen Problem formulation as given by van Vyve and Wolsey in the article Approximate extended formulations'', we investigate the effects of small variations onto the performance of contemporary mixed integer programming solvers. We will show that even minor changes in the formulation of the model can result in performance difference of more than a factor of 1000. As the results show it is not obvious which changes will result in performance improvements and which not.}, language = {en} } @misc{AchterbergRaack, author = {Achterberg, Tobias and Raack, Christian}, title = {The MCF-Separator -- Detecting and Exploiting Multi-Commodity Flow Structures in MIPs}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-11592}, number = {09-38}, abstract = {Given a general mixed integer program (MIP), we automatically detect block structures in the constraint matrix together with the coupling by capacity constraints arising from multi-commodity-flow formulations. We identify the underlying graph and generate cutting planes based on cuts in the detected network. Our implementation adds a separator to the branch-and-cut libraries of SCIP and CPLEX. We make use of the complemented mixed integer rounding framework (cMIR) but provide a special purpose aggregation heuristic that exploits the network structure. Our separation scheme speeds-up the computation for a large set of MIPs coming from network design problems by a factor of two on average.}, language = {en} } @article{AchterbergRaack2010, author = {Achterberg, Tobias and Raack, Christian}, title = {The MCF-Separator - Detecting and Exploiting Multi-Commodity Flows in MIPs}, series = {Mathematical Programming C}, journal = {Mathematical Programming C}, number = {2}, pages = {125 -- 165}, year = {2010}, language = {en} } @misc{AckermannErdmannRoitzsch, author = {Ackermann, J{\"o}rg and Erdmann, Bodo and Roitzsch, Rainer}, title = {A self-adaptive multilevel finite element method for the stationary Schr{\"o}dinger equation in three space dimensions.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-1403}, number = {SC-94-10}, abstract = {An error controlled finite elemente method (FEM) for solving stationary Schr{\"o}dinger equations in three space dimensions is proposed. The method is based on an adaptive space discretization into tetrahedra and local polynomial basis functions of order \$p=1\$--\$5\$ defined on these tetrahedra. According to a local error estimator the triangulation is automatically adapted to the solution. Numerical results for standard problems appearing in vibrational motion and molecular structure calculations are presented and discussed. Relative precisions better than 1e-8 are obtained. For equilateral H\$_3^{++}\$ the adaptive FEM turns out to be superior to global basis set expansions in the literature. Our precise FEM results exclude in a definite manner the stability or metastability of equilateral H\$_3^{++}\$ in its groundstate.}, language = {en} } @article{AckermannErdmannRoitzsch1994, author = {Ackermann, J{\"o}rg and Erdmann, Bodo and Roitzsch, Rainer}, title = {A self-adaptive multilevel finite element method for the stationary Schr{\"o}dinger equation in three space dimensions}, series = {J. Chem. Phys.}, volume = {101}, journal = {J. Chem. Phys.}, pages = {7643 -- 7650}, year = {1994}, language = {en} } @misc{AckermannHELFRICH, author = {Ackermann, J{\"o}rg and HELFRICH, K.}, title = {Radius of Convergence of the 1/Z-Expansion for Diatomic Molecules: The Ground State of the Isoelectronic H2Sequence.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-721}, number = {SC-92-02}, abstract = {Using the perturbational-variational Rayleigh-Ritz matrix formalism, the 1/Z-expansion for the ground state of the isoelectronic \$H_2\$ sequence in the range of the internuclear distance \$0.2\le R \le 9.0\$ is calculated. Also lower bounds of the radius of convergence, based on Kato's theory of linear operators, are given. The numerical results of the 1/Z-expansion can be compared with the exact results and do not converge in the whole R-range. This behavior is in qualitative agreement with the lower bounds for the radius of convergence and enlights some still open properties of 1/Z- expansions for this sequence in the literature. {\bf PACS:} 31.15 + q; 31.20 Di; 31.20 Tz.}, language = {en} } @misc{AckermannRoitzsch, author = {Ackermann, J{\"o}rg and Roitzsch, Rainer}, title = {On a Two-Dimensional Multilevel Adaptive Finite Element Method for the Time-Independent Schr{\"o}dinger-Equation.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-1086}, number = {SC-93-12}, abstract = {The subject of this study is a multilevel Finite Element Method based on an error estimator and step by step grid refinement as an universal tool for solving time--independent Schr{\"o}dinger--eigenvalue problems. Numerical results for standard problems appearing in vibrational motion and molecular electronic structure calculations are given and discussed.}, language = {en} } @misc{AckermannWulkow, author = {Ackermann, J{\"o}rg and Wulkow, Michael}, title = {MACRON - A Program Package for Macromalecular Reaction Kinetics.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-423}, number = {SC-90-14}, abstract = {This paper presents the new program package MACRON for the simulation of macromolecular kinetics including standard chemical reactions. Such problems lead to countable (possibly) infinite systems of ordinary differential equations (CODE's), which are numerically treated by the so-called discrete Galerkin method here. By a chemical compiler the required analytical preprocessing is performed, such that the complete reaction system, standard kinetics as well as macromolecular reactions, can be entered in the chemical formalism. Typical macromolecular reaction steps are chain addition, termination, chain transfer and degradation (cracking). In order to ensure efficiency and reliability, high sophisticated numerical routines are built within the package. MACRON can be used without a detailed knowledge of the used numerical methods. As an illustration the application of MACRON to some realistic problems is presented.}, language = {en} } @misc{AckermannWulkow, author = {Ackermann, J{\"o}rg and Wulkow, Michael}, title = {The Treatment of Macromolecular Processes with Chain-Length-Dependent Reaction Coefficients - An Examplefrom Soot Formation.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-682}, number = {SC-91-18}, abstract = {The description of chain length distributions in macromolecular reaction kinetics leads to so-called countable systems of differential equations. In particular, when the appearing reaction rate coefficients depend on the chain length of the reacting macromolecules itself, an efficient numerical treatment of these systems is very difficult. Then even the evaluation of the right-hand side of the system can become prohibitively expensive with respect to computing time. In this paper we show how the discrete Galerkin method can be applied to such problems. The existing algorithm CODEX is improved by use of a multiplicative error correction scheme for time discretization and a new type of numerical preprocessing by means of a Gauss summation. Both ideas are exemplary for a wide class of approximation types and are described very briefly here. The new numerical techniques are tested on an example from soot formation, where the coagulation of molecules is modeled in terms of reaction coefficients depending on the surface of the particles and their collision frequency.}, language = {en} } @misc{AdolfsonHelgesson2004, type = {Master Thesis}, author = {Adolfson, Jon and Helgesson, Johan}, title = {Generation of Smooth Non-Manifold Surfaces from Segmented Image Data}, year = {2004}, language = {en} } @phdthesis{Agarwal, author = {Agarwal, Animesh}, title = {Path Integral Techniques in Molecular Dynamics Simulations of Open Boundary Systems}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:188-fudissthesis000000103020-4}, language = {en} } @misc{AgarwalWangSchuetteetal., author = {Agarwal, Animesh and Wang, Han and Sch{\"u}tte, Christof and Delle Site, Luigi}, title = {Chemical potential of liquids and mixtures via Adaptive Resolution Simulation}, issn = {1438-0064}, doi = {10.1063/1.4886807}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-50972}, abstract = {We employ the adaptive resolution approach AdResS, in its recently developed Grand Canonicallike version (GC-AdResS) [Wang et al. Phys.Rev.X 3, 011018 (2013)], to calculate the excess chemical potential, \$μ^{ex}\$, of various liquids and mixtures. We compare our results with those obtained from full atomistic simulations using the technique of thermodynamic integration and show a satisfactory agreement. In GC-AdResS the procedure to calculate \$μ^{ex}\$ corresponds to the process of standard initial equilibration of the system; this implies that, independently of the specific aim of the study, \$μ^{ex}\$, for each molecular species, is automatically calculated every time a GC-AdResS simulation is performed.}, language = {en} } @article{AgarwalWangSchuetteetal., author = {Agarwal, Animesh and Wang, Han and Sch{\"u}tte, Christof and Delle Site, Luigi}, title = {Chemical potential of liquids and mixtures via Adaptive Resolution Simulation}, series = {The Journal of Chemical Physics}, volume = {141}, journal = {The Journal of Chemical Physics}, doi = {10.1063/1.4886807}, pages = {034102}, language = {en} } @inproceedings{AgcosBodermannBurgeretal., author = {Agcos, Emil and Bodermann, Bernd and Burger, Sven and Dai, Gaoliang and Endres, Johannes and Hansen, Poul-Erik and Nielson, Lars and Madsen, Morten and Heidenreich, Sebastian and Krumrey, Michael and Loechel, Bernd and Probst, J{\"u}rgen and Scholze, Frank and Soltwisch, Victor and Wurm, Matthias}, title = {Scatterometry reference standards to improve tool matching and traceability in lithographical nanomanufacturing}, series = {Proc. SPIE}, volume = {9556}, booktitle = {Proc. SPIE}, doi = {10.1117/12.2190409}, pages = {955610}, language = {en} } @inproceedings{AgudoJacomeHegePaetschetal., author = {Agudo J{\´a}come, Leonardo and Hege, Hans-Christian and Paetsch, Olaf and P{\"o}thkow, Kai}, title = {3D Reconstruction, Visualization and Quantification of Dislocations from Transmission Electron Microscopy Stereo-Pairs}, series = {Microscopy and Microanalysis 2016, July 24-28 Columbus, Ohio}, booktitle = {Microscopy and Microanalysis 2016, July 24-28 Columbus, Ohio}, language = {en} } @article{AgudoJacomeHegePaetschetal., author = {Agudo J{\´a}come, Leonardo and Hege, Hans-Christian and Paetsch, Olaf and P{\"o}thkow, Kai}, title = {Three-dimensional reconstruction and quantification of dislocation substructures from transmission electron microscopy stereo pairs}, series = {Ultramicroscopy}, volume = {195}, journal = {Ultramicroscopy}, doi = {10.1016/j.ultramic.2018.08.015}, pages = {157 -- 170}, abstract = {A great amount of material properties is strongly influenced by dislocations, the carriers of plastic deformation. It is therefore paramount to have appropriate tools to quantify dislocation substructures with regard to their features, e.g., dislocation density, Burgers vectors or line direction. While the transmission electron microscope (TEM) has been the most widely-used equipment implemented to investigate dislocations, it usually is limited to the two-dimensional (2D) observation of three-dimensional (3D) structures. We reconstruct, visualize and quantify 3D dislocation substructure models from only two TEM images (stereo pairs) and assess the results. The reconstruction is based on the manual interactive tracing of filiform objects on both images of the stereo pair. The reconstruction and quantification method are demonstrated on dark field (DF) scanning (S)TEM micrographs of dislocation substructures imaged under diffraction contrast conditions. For this purpose, thick regions (>300 nm) of TEM foils are analyzed, which are extracted from a Ni-base superalloy single crystal after high temperature creep deformation. It is shown how the method allows 3D quantification from stereo pairs in a wide range of tilt conditions, achieving line length and orientation uncertainties of 3\% and 7°, respectively. Parameters that affect the quality of such reconstructions are discussed.}, language = {en} } @misc{AgudoJacomeHegePaetschetal., author = {Agudo J{\´a}come, Leonardo and Hege, Hans-Christian and Paetsch, Olaf and P{\"o}thkow, Kai}, title = {Three-Dimensional Reconstruction and Quantification of Dislocation Substructures from Transmission Electron Microscopy Stereo-Pairs}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-70339}, abstract = {A great amount of material properties is strongly influenced by dislocations, the carriers of plastic deformation. It is therefore paramount to have appropriate tools to quantify dislocation substructures with regard to their features, e.g., dislocation density, Burgers vectors or line direction. While the transmission electron microscope (TEM) has been the most widely-used equipment implemented to investigate dislocations, it usually is limited to the two-dimensional (2D) observation of three-dimensional (3D) structures. We reconstruct, visualize and quantify 3D dislocation substructure models from only two TEM images (stereo-pairs) and assess the results. The reconstruction is based on the manual interactive tracing of filiform objects on both images of the stereo-pair. The reconstruction and quantification method are demonstrated on dark field (DF) scanning (S)TEM micrographs of dislocation substructures imaged under diffraction contrast conditions. For this purpose, thick regions (> 300 nm) of TEM foils are analyzed, which are extracted from a Ni-base superalloy single crystal after high temperature creep deformation. It is shown how the method allows 3D quantification from stereo-pairs in a wide range of tilt conditions, achieving line length and orientation uncertainties of 3 \% and 7°, respectively. Parameters that affect the quality of such reconstructions are discussed.}, language = {en} } @inproceedings{AhibozAndresenManleyetal., author = {Ahiboz, Doguscan and Andresen, Elina and Manley, Phillip and Resch Genger, Ute and W{\"u}rth, Christian and Becker, Christiane}, title = {Enhanced Photon Upconversion Using Erbium-Doped Nanoparticles Interacting with Silicon Metasurfaces}, series = {IEEE 48th Photovoltaic Specialists Conference (PVSC)}, booktitle = {IEEE 48th Photovoltaic Specialists Conference (PVSC)}, doi = {10.1109/PVSC43889.2021.9518495}, pages = {2008 -- 2010}, language = {en} } @article{AhibozAndresenManleyetal., author = {Ahiboz, Doguscan and Andresen, Elina and Manley, Phillip and Resch-Genger, Ute and W{\"u}rth, Christian and Becker, Christiane}, title = {Metasurface-Enhanced Photon Upconversion upon 1550 nm Excitation}, series = {Adv. Opt. Mater.}, volume = {9}, journal = {Adv. Opt. Mater.}, doi = {10.1002/adom.202101285}, pages = {2101285}, language = {en} } @misc{AhmadiGritzbachLundNguyenetal.2015, author = {Ahmadi, Sepideh and Gritzbach, Sascha F. and Lund-Nguyen, Kathryn and McCullough-Amal, Devita}, title = {Rolling Stock Rotation Optimization in Days of Strike: An Automated Approach for Creating an Alternative Timetable}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-56425}, year = {2015}, abstract = {The operation of a railway network as large as Deutsche Bahn's Intercity Express (ICE) hinges on a number of factors, such as the availability of personnel and the assignment of physical vehicles to a timetable schedule, a problem known as the rolling stock rotation problem (RSRP). In this paper, we consider the problem of creating an alternative timetable in the case that there is a long-term disruption, such as a strike, and the effects that this alternative timetable has on the resulting vehicle rotation plan. We define a priority measure via the Analytic Hierarchy Process (AHP) to determine the importance of each trip in the timetable and therefore which trips to cancel or retain. We then compare our results with those of a limited timetable manually designed by Deutsche Bahn (DB). We find that while our timetable results in a more expensive rotation plan, its flexibility lends itself to a number of simple improvements. Furthermore, our priority measure has the potential to be integrated into the rolling stock rotation optimization process, in particular, the Rotation Optimizer for Railways (ROTOR) software, via the cost function. Ultimately, our method provides the foundation for an automated way of creating a new timetable quickly, and potentially in conjunction with a new rotation plan, in the case of a limited scenario.}, language = {en} } @article{AhufingerCorbalanCataliottietal.2002, author = {Ahufinger, Ver{\`o}nica and Corbal{\´a}n, R. and Cataliotti, F. S. and Burger, Sven and Minardi, F. and Fort, C.}, title = {Electromagnetically induced transparency in a Bose-Einstein condensate}, series = {Opt. Comm.}, volume = {211}, journal = {Opt. Comm.}, doi = {10.1016/S0030-4018(02)01826-6}, pages = {159}, year = {2002}, language = {en} } @phdthesis{Aiche, author = {Aiche, Stephan}, title = {Inferring Proteolytic Processes from Mass Spectrometry Time Series Data}, language = {en} } @article{AicheReinertSchuetteetal.2012, author = {Aiche, Stephan and Reinert, Knut and Sch{\"u}tte, Christof and Hildebrand, Diana and Schl{\"u}ter, Hartmut and Conrad, Tim}, title = {Inferring Proteolytic Processes from Mass Spectrometry Time Series Data Using Degradation Graphs}, series = {PLoS ONE}, volume = {7}, journal = {PLoS ONE}, number = {7}, publisher = {Public Library of Science}, doi = {10.1371/journal.pone.0040656}, pages = {e40656}, year = {2012}, language = {en} } @article{AignerClarnerLiersetal., author = {Aigner, Kevin-Martin and Clarner, Jan-Patrick and Liers, Frauke and Martin, Alexander}, title = {Robust Approximation of Chance Constrained DC Optimal Power Flow under Decision-Dependent Uncertainty}, series = {European Journal of Operational Research}, journal = {European Journal of Operational Research}, abstract = {We propose a mathematical optimization model and its solution for joint chance constrained DC Optimal Power Flow. In this application, it is particularly important that there is a high probability of transmission limits being satisfied, even in the case of uncertain or fluctuating feed-in from renewable energy sources. In critical network situations where the network risks overload, renewable energy feed-in has to be curtailed by the transmission system operator (TSO). The TSO can reduce the feed-in in discrete steps at each network node. The proposed optimization model minimizes curtailment while ensuring that there is a high probability of transmission limits being maintained. The latter is modeled via (joint) chance constraints that are computationally challenging. Thus, we propose a solution approach based on the robust safe approximation of these constraints. Hereby, probabilistic constraints are replaced by robust constraints with suitably defined uncertainty sets constructed from historical data. The ability to discretely control the power feed-in then leads to a robust optimization problem with decision-dependent uncertainties, i.e. the uncertainty sets depend on decision variables. We propose an equivalent mixed-integer linear reformulation for box uncertainties with the exact linearization of bilinear terms. Finally, we present numerical results for different test cases from the Nesta archive, as well as for a real network. We consider the discrete curtailment of solar feed-in, for which we use real-world weather and network data. The experimental tests demonstrate the effectiveness of this method and run times are very fast. Moreover, on average the calculated robust solutions only lead to a small increase in curtailment, when compared to nominal solutions.}, language = {en} } @article{AkbariShandizBoulosSavarssonetal.2017, author = {Akbari Shandiz, Mohsen and Boulos, Paul and S{\ae}varsson, Stefan and Ramm, Heiko and Fu, Chun Kit and Miller, Stephen and Zachow, Stefan and Anglin, Carolyn}, title = {Changes in Knee Shape and Geometry Resulting from Total Knee Arthroplasty}, series = {Journal of Engineering in Medicine}, volume = {232}, journal = {Journal of Engineering in Medicine}, number = {1}, doi = {10.1177/0954411917743274}, pages = {67 -- 79}, year = {2017}, abstract = {Changes in knee shape and geometry resulting from total knee arthroplasty can affect patients in numerous important ways: pain, function, stability, range of motion, and kinematics. Quantitative data concerning these changes have not been previously available, to our knowledge, yet are essential to understand individual experiences of total knee arthroplasty and thereby improve outcomes for all patients. The limiting factor has been the challenge of accurately measuring these changes. Our study objective was to develop a conceptual framework and analysis method to investigate changes in knee shape and geometry, and prospectively apply it to a sample total knee arthroplasty population. Using clinically available computed tomography and radiography imaging systems, the three-dimensional knee shape and geometry of nine patients (eight varus and one valgus) were compared before and after total knee arthroplasty. All patients had largely good outcomes after their total knee arthroplasty. Knee shape changed both visually and numerically. On average, the distal condyles were slightly higher medially and lower laterally (range: +4.5 mm to -4.4 mm), the posterior condyles extended farther out medially but not laterally (range: +1.8 to -6.4 mm), patellofemoral distance increased throughout flexion by 1.8-3.5 mm, and patellar thickness alone increased by 2.9 mm (range: 0.7-5.2 mm). External femoral rotation differed preop and postop. Joint line distance, taking cartilage into account, changed by +0.7 to -1.5 mm on average throughout flexion. Important differences in shape and geometry were seen between pre-total knee arthroplasty and post-total knee arthroplasty knees. While this is qualitatively known, this is the first study to report it quantitatively, an important precursor to identifying the reasons for the poor outcome of some patients. Using the developed protocol and visualization techniques to compare patients with good versus poor clinical outcomes could lead to changes in implant design, implant selection, component positioning, and surgical technique. Recommendations based on this sample population are provided. Intraoperative and postoperative feedback could ultimately improve patient satisfaction.}, language = {en} } @article{AkemideForcrandFujisakietal.1995, author = {Akemi, K. and deForcrand, Ph. and Fujisaki, M. and Hashimoto, T. and Hege, Hans-Christian and Hioki, S. and Miyamura, O. and Nakamura, A. and Okuda, M. and Stamatescu, I. O. and Tago, Yoshio and Takaishi, T.}, title = {Quantum Chromodynamics Simulations on a Non-Dedicated Highly Parallel Computer}, series = {Comp. Phys. Comm}, volume = {90}, journal = {Comp. Phys. Comm}, doi = {10.1016/0010-4655(95)00082-Q}, pages = {201 -- 214}, year = {1995}, language = {en} } @article{AkemiForcrandFujisakietal.1992, author = {Akemi, K. and Forcrand, Ph. de and Fujisaki, M. and Hashimoto, T. and Hege, Hans-Christian and Hioki, S. and Makino, J. and Miyamura, O. and Nakamura, A. and Okuda, M. and Stamatescu, I. O. and Tago, Yoshio and Takaishi, T.}, title = {SU(3) Renormalization Group Study on Parallel Computer AP 1000}, series = {Nucl. Phys. B Proc. Suppl. 26}, journal = {Nucl. Phys. B Proc. Suppl. 26}, doi = {10.1016/0920-5632(92)90293-2}, pages = {420 -- 422}, year = {1992}, language = {en} } @article{AkemiForcrandFujisakietal.1992, author = {Akemi, K. and Forcrand, Ph. de and Fujisaki, M. and Hashimoto, T. and Hege, Hans-Christian and Hioki, S. and Makino, J. and Miyamura, O. and Nakamura, A. and Okuda, M. and Stamatescu, I. O. and Tago, Yoshio and Takaishi, T.}, title = {QCD on the Highly Parallel Computer AP 1000}, series = {Nucl. Phys. B Proc. Suppl. 26}, journal = {Nucl. Phys. B Proc. Suppl. 26}, doi = {10.1016/0920-5632(92)90358-Y}, pages = {644 -- 646}, year = {1992}, language = {en} } @masterthesis{Akil, type = {Bachelor Thesis}, author = {Akil, Fatima}, title = {Lineare Gleichungssysteme modulo T}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-71560}, pages = {52}, abstract = {Mit dem Voranschreiten der Technologie erhalten die {\"o}ffentlichen Verkehrsmittel eine gr{\"o}ßere Bedeutung. Die Bef{\"o}rderung mehrerer Personen er{\"o}ffnet der Gesellschaft viele M{\"o}glichkeiten, unter Anderem den Vorteil der Zeitersparnis. Die Dauer des Verkehrswegs mit {\"o}ffentlichen Verkehrsmitteln ist h{\"a}ufig geringer, als die mit individuellen Verkehrsmitteln. Jedes {\"o}ffentliche Transportmittel ist mit einem Fahrplan versehen. Dieser bietet Passagieren, die {\"o}ffentliche Verkehrsmittel {\"o}fter nutzen, eine Strukturierung und Planung ihrer Zeit. Dabei lassen sich Taktfahrpl{\"a}ne aufgrund ihres periodischen Verhaltens leicht einpr{\"a}gen. Dieses periodische Verhalten ist durch mathematische Modellierungen darstellbar. Das pers{\"o}nliche Nutzverhalten vieler B{\"u}rger im Personenverkehr ist auf die {\"o}ffentlichen Verkehrsmittel beschr{\"a}nkt. Diese beinhalten im Gegensatz zum individuellen Verkehrsmittel eine Wartezeit. Dabei stellt sich die Frage, ob man anhand mathematischer Modelle diese Wartezeit minimieren kann. Eine bekannte mathematische Modellierung dieses Problems ist das Periodic Event Scheduling Problem (PESP). Die optimale Planung eines periodischen Taktfahrplanes steht im Vordergrund. W{\"a}hrend ich dieses Problem betrachtet habe, wurde ich auf das Rechnen mit linearen Gleichungssystemen modulo T aufmerksam. Bei periodischen Taktfahrpl{\"a}nen wird ein einheitliches zeitliches Muster, welches sich nach T Minuten wiederholt, betrachtet. Das dabei zu betrachtende L{\"o}sungsproblem er{\"o}ffnet ein Teilgebiet der Mathematik, welches bislang nicht im Vordergrund stand: Das L{\"o}sen linearer Gleichungen modulo T, wobei T f{\"u}r die Zeit in Minuten steht und somit 60 ist. Da 60 keine Primzahl ist, kann - wie im Laufe der Arbeit pr{\"a}sentiert - das lineare Gleichungssystem nicht mehr {\"u}ber einen K{\"o}rper gel{\"o}st werden. Lineare Gleichungssysteme werden nun {\"u}ber Nicht-K{\"o}rpern betrachtet. Die Literatur weist sowohl im deutschsprachigem als auch im englischsprachigen Raum wenig Umfang bez{\"u}glich linearer Gleichungssysteme {\"u}ber Nicht-K{\"o}rper auf. Der Bestand an Fachliteratur bez{\"u}glich den Themen lineare diophantische Gleichungssysteme, Hermite- Normalform und Smith-Normalform ist zurzeit gering, dennoch erreichbar, beispielsweise in [1], welches in dieser Bachelorarbeit genutzt wurde. Insbesondere wurde ich bei der Suche nach geeigneter Literatur zu linearen Gleichungssystemen {\"u}ber Restklassenringe, die keinen K{\"o}rper bilden, nicht f{\"u}ndig. Dabei recherchierte ich sowohl in den Universit{\"a}tsbibliotheken als auch in webbasierenden Suchmaschinen. Aufgrund dem geringen Bestand an Fachliteratur in diesem Kontext, war ich gezwungen, an vielen Stellen eigene logische Verkn{\"u}pfungen zu konzipieren und zu beweisen. Dies brachte viele Schwierigkeiten mit sich, die mit bestm{\"o}glichem Verst{\"a}ndnis bearbeitet wurden. Abseits der Zug{\"a}nglichkeit der Literatur, finde ich es sehr {\"u}berraschend, dass sich viele Professoren der Mathematik mit diesem Themenbereich nicht besch{\"a}ftigten. Insbesondere gingen von den Dozenten, die ich um Literaturempfehlung bat, kein Werk aus. Damit wurde das Thema "Lineare Gleichungssysteme Modulo T" einerseits eine große Herausforderung, andererseits eine große Motivation, da ich mit dieser Bachelorarbeit vielen Interessenten der Mathematik als Sekund{\"a}rliteratur dienen kann.}, language = {de} } @article{AlHajjSahuLamardetal., author = {Al Hajj, Hassan and Sahu, Manish and Lamard, Mathieu and Conze, Pierre-Henri and Roychowdhury, Soumali and Hu, Xiaowei and Marsalkaite, Gabija and Zisimopoulos, Odysseas and Dedmari, Muneer Ahmad and Zhao, Fenqiang and Prellberg, Jonas and Galdran, Adrian and Araujo, Teresa and Vo, Duc My and Panda, Chandan and Dahiya, Navdeep and Kondo, Satoshi and Bian, Zhengbing and Bialopetravicius, Jonas and Qiu, Chenghui and Dill, Sabrina and Mukhopadyay, Anirban and Costa, Pedro and Aresta, Guilherme and Ramamurthy, Senthil and Lee, Sang-Woong and Campilho, Aurelio and Zachow, Stefan and Xia, Shunren and Conjeti, Sailesh and Armaitis, Jogundas and Heng, Pheng-Ann and Vahdat, Arash and Cochener, Beatrice and Quellec, Gwenole}, title = {CATARACTS: Challenge on Automatic Tool Annotation for cataRACT Surgery}, series = {Medical Image Analysis}, volume = {52}, journal = {Medical Image Analysis}, number = {2}, publisher = {Elsevier}, doi = {10.1016/j.media.2018.11.008}, pages = {24 -- 41}, abstract = {Surgical tool detection is attracting increasing attention from the medical image analysis community. The goal generally is not to precisely locate tools in images, but rather to indicate which tools are being used by the surgeon at each instant. The main motivation for annotating tool usage is to design efficient solutions for surgical workflow analysis, with potential applications in report generation, surgical training and even real-time decision support. Most existing tool annotation algorithms focus on laparoscopic surgeries. However, with 19 million interventions per year, the most common surgical procedure in the world is cataract surgery. The CATARACTS challenge was organized in 2017 to evaluate tool annotation algorithms in the specific context of cataract surgery. It relies on more than nine hours of videos, from 50 cataract surgeries, in which the presence of 21 surgical tools was manually annotated by two experts. With 14 participating teams, this challenge can be considered a success. As might be expected, the submitted solutions are based on deep learning. This paper thoroughly evaluates these solutions: in particular, the quality of their annotations are compared to that of human interpretations. Next, lessons learnt from the differential analysis of these solutions are discussed. We expect that they will guide the design of efficient surgery monitoring tools in the near future.}, language = {en} } @article{AlbrechtCeynowaDegkwitzetal., author = {Albrecht, Rita and Ceynowa, Klaus and Degkwitz, Andreas and Kende, Jiri and Koch, Thorsten and Messmer, Gabriele and Risch, Uwe and Rusch, Beate and Scheuerl, Robert and Voß, Michael}, title = {Cloudbasierte Infrastruktur f{\"u}r Bibliotheksdaten - auf dem Weg zu einer Neuordnung der deutschen Verbundlandschaft}, series = {Bibliothek Forschung und Praxis}, volume = {37}, journal = {Bibliothek Forschung und Praxis}, number = {3}, doi = {10.1515/bfp-2013-0044}, pages = {279 -- 287}, abstract = {Im Oktober 2012 hatte die Deutsche Forschungsgemeinschaft (DFG) ein F{\"o}rderprogramm zur Neuausrichtung {\"u}berregionaler Informationsservices ausgeschrieben, um eine umfassende Reorganisation bestehender Infrastrukturen anzustoßen, die mit den Empfehlungen des Wissenschaftsrates zur Zukunft der bibliothekarischen Verbundsysteme in Deutschland gefordert wurde. Im Themenfeld „Bibliotheksdateninfrastruktur und Lokale Systeme" der DFG-Ausschreibung wurde das vom Hessischen Bibliotheksinformationssystem (HeBIS), vom Bibliotheksverbund Bayern (BVB) und vom Kooperativen Bibliotheksverbund Berlin-Brandenburg (KOBV) beantragte Vorhaben „Cloudbasierte Infrastruktur f{\"u}r Bibliotheksdaten" (CIB) bewilligt. Das Projekt zielt auf die {\"U}berf{\"u}hrung bibliothekarischer Workflows und Dienste in cloudbasierte Arbeitsumgebungen und die sukzessive Abl{\"o}sung traditioneller Verbund- und Lokalsysteme durch internationale Systemplattformen. Zu den Arbeitspaketen des Vorhabens geh{\"o}rt u. a. die Einbindung von Norm- und Fremddatenangeboten und von weiteren Services in diese Plattformen.}, language = {de} } @article{AlchikhConradHoppeetal., author = {Alchikh, Maren and Conrad, Tim and Hoppe, Christian and Ma, Xiaolin and Broberg, Eeva K. and Penttinen, P. and Reiche, J. and Biere, Barbara and Schweiger, Brunhilde and Rath, Barbara}, title = {Are we missing respiratory viral infections in infants and children? Comparison of a hospital-based quality management system with standard of care. Clinical Microbiology and Infection}, series = {Clinical Microbiology and Infection}, journal = {Clinical Microbiology and Infection}, number = {06/18}, doi = {10.1016/j.cmi.2018.05.023}, pages = {1 -- 1}, language = {en} } @article{AlchikhConradMaetal., author = {Alchikh, Maren and Conrad, Tim and Ma, Xiaolin and Broberg, Eeva K. and Penttinen, P. and Reiche, J. and Biere, Barbara and Schweiger, Brunhilde and Rath, Barbara and Hoppe, Christian}, title = {Are we missing respiratory viral infections in infants and children? Comparison of a hospital-based quality management system with standard of care}, series = {Clinical Microbiology and Infection}, volume = {25}, journal = {Clinical Microbiology and Infection}, number = {3}, issn = {1469-0691}, doi = {10.1016/j.cmi.2018.05.023}, pages = {380.e9 -- 380.e16}, language = {en} } @article{AlchikhConradObermeieretal., author = {Alchikh, Maren and Conrad, Tim and Obermeier, Patrick and Ma, Xiaolin and Schweiger, Brunhilde and Opota, Onya and Rath, Barbara}, title = {Disease Burden and Inpatient Management of Children with Acute Respiratory Viral Infections during the Pre-COVID Era in Germany: A Cost-of-Illness Study}, series = {Viruses}, volume = {16}, journal = {Viruses}, number = {4}, doi = {10.3390/v16040507}, abstract = {Respiratory viral infections (RVIs) are common reasons for healthcare consultations. The inpatient management of RVIs consumes significant resources. From 2009 to 2014, we assessed the costs of RVI management in 4776 hospitalized children aged 0-18 years participating in a quality improvement program, where all ILI patients underwent virologic testing at the National Reference Centre followed by detailed recording of their clinical course. The direct (medical or non-medical) and indirect costs of inpatient management outside the ICU ('non-ICU') versus management requiring ICU care ('ICU') added up to EUR 2767.14 (non-ICU) vs. EUR 29,941.71 (ICU) for influenza, EUR 2713.14 (non-ICU) vs. EUR 16,951.06 (ICU) for RSV infections, and EUR 2767.33 (non-ICU) vs. EUR 14,394.02 (ICU) for human rhinovirus (hRV) infections, respectively. Non-ICU inpatient costs were similar for all eight RVIs studied: influenza, RSV, hRV, adenovirus (hAdV), metapneumovirus (hMPV), parainfluenza virus (hPIV), bocavirus (hBoV), and seasonal coronavirus (hCoV) infections. ICU costs for influenza, however, exceeded all other RVIs. At the time of the study, influenza was the only RVI with antiviral treatment options available for children, but only 9.8\% of influenza patients (non-ICU) and 1.5\% of ICU patients with influenza received antivirals; only 2.9\% were vaccinated. Future studies should investigate the economic impact of treatment and prevention of influenza, COVID-19, and RSV post vaccine introduction.}, language = {en} } @misc{AlevrasGroetschelJonasetal., author = {Alevras, Dimitris and Gr{\"o}tschel, Martin and Jonas, Peter and Paul, Ulrich and Wess{\"a}ly, Roland}, title = {Survivable Mobile Phone Architectures: Models and Solution Methods}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-2582}, number = {SC-96-48}, abstract = {In the highly competitive area of telecommunications, cost, quality, and network management are among the most important aspects to be considered when designing a network. We study the problem of dimensioning a telecommunication network that is still operating in case of a failure of a network component. Given a demand between each pair of nodes of a telecommunication network and a finite set of possible capacities for each edge of the network, we consider the problem of deciding what capacity to install on each edge of the network in order to minimize the building cost of the network and to satisfy the demand between each pair of nodes, even if a network component fails. The routing of the demands must satisfy the following additional restrictions: (a) there is a maximum number of nodes allowed in each path between any pair of nodes (path length restriction), and (b) there is a maximum percentage of the demand between each pair of nodes that can be routed through any network component (diversification restriction). Moreover, the chosen capacities must be such that, for every single node or single edge failure, a certain percentage of the demand between any pair of nodes is reroutable (i.e. it ``survives'' the particular failure). We formulate the problem as a mixed integer linear programming problem and present a cutting plane algorithm as well as several heuristics for its solution. Furthermore, we discuss several ways to implement survivability into a telecommunication network.}, language = {en} } @article{AlevrasGroetschelJonasetal.1998, author = {Alevras, Dimitris and Gr{\"o}tschel, Martin and Jonas, Peter and Paul, Uwe and Wess{\"a}ly, Roland}, title = {Survivable Mobile Phone Network Architectures}, series = {IEEE Communications Magazine}, journal = {IEEE Communications Magazine}, pages = {88 -- 93}, year = {1998}, language = {en} } @misc{AlevrasGroetschelWessaely, author = {Alevras, Dimitris and Gr{\"o}tschel, Martin and Wess{\"a}ly, Roland}, title = {Cost-Efficient Network Synthesis from Leased Lines}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-2912}, number = {SC-97-22}, abstract = {Given a communication demand between each pair of nodes of a network we consider the problem of deciding what capacity to install on each edge of the network in order to minimize the building cost of the network and to satisfy the demand between each pair of nodes. The feasible capacities that can be leased from a network provider are of a particular kind in our case. There are a few so-called basic capacities having the property that every basic capacity is an integral multiple of every smaller basic capacity. An edge can be equipped with a capacity only if it is an integer combination of the basic capacities. We treat, in addition, several restrictions on the routings of the demands (length restriction, diversification) and failures of single nodes or single edges. We formulate the problem as a mixed integer linear programming problem and develop a cutting plane algorithm as well as several heuristics to solve it. We report on computational results for real world data.}, language = {en} } @misc{AlevrasGroetschelWessaely, author = {Alevras, Dimitris and Gr{\"o}tschel, Martin and Wess{\"a}ly, Roland}, title = {Capacity and Survivability Models for Telecommunication Networks}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-2931}, number = {SC-97-24}, abstract = {Designing low-cost networks that survive certain failure situations is one of the prime tasks in the telecommunication industry. In this paper we survey the development of models for network survivability used in practice in the last ten years. We show how algorithms integrating polyhedral combinatorics, linear programming, and various heuristic ideas can help solve real-world network dimensioning instances to optimality or within reasonable quality guarantees in acceptable running times. The most general problem type we address is the following. Let a communication demand between each pair of nodes of a telecommunication network be given. We consider the problem of choosing, among a discrete set of possible capacities, which capacity to install on each of the possible edges of the network in order to (i) satisfy all demands, (ii) minimize the building cost of the network. \noindent In addition to determining the network topology and the edge capacities we have to provide, for each demand, a routing such that (iii) no path can carry more than a given percentage of the demand, (iv) no path in the routing exceeds a given length. \noindent We also have to make sure that (v) for every single node or edge failure, a certain percentage of the demand is reroutable. \noindent Moreover, for all failure situations feasible routings must be computed. The model described above has been developed in cooperation with a German mobile phone provider. We present a mixed-integer programming formulation of this model and computational results with data from practice.}, language = {en} } @misc{AlevrasGroetschelWessaely, author = {Alevras, Dimitris and Gr{\"o}tschel, Martin and Wess{\"a}ly, Roland}, title = {A Network Dimensioning Tool}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-2591}, number = {SC-96-49}, abstract = {Designing low cost networks that survive certain failure situations belongs to one of the prime tasks in the telecommunications industry. In this paper we describe a mathematical model combining several aspects of survivability that are elsewhere treated in a hierarchical fashion. We present mathematical investigations of this integrated model, a cutting plane algorithm, as well as several heuristics for its solution. Moreover, we report computational results with real world data. The problem we address is the following. Suppose, between each pair of nodes in a region, a communication demand is given. We want to determine the topology of a telecommunication network connecting the given nodes and to dimension all potential physical links. For each link, the possible capacities are restricted to a given finite set. The capacities must be chosen such that the communication demands are satisfied, even if certain network components fail, and such that the network building costs are as small as possible. Moreover, for each pair of nodes and each failure situation, we want to determine the paths on which the demand between the nodes is routed.}, language = {en} } @article{AlevrasGroetschelWessaely1998, author = {Alevras, Dimitris and Gr{\"o}tschel, Martin and Wess{\"a}ly, Roland}, title = {Cost-efficient network synthesis from leased lines}, series = {Annals of Operations Research}, volume = {76}, journal = {Annals of Operations Research}, pages = {1 -- 20}, year = {1998}, language = {en} } @inproceedings{AlevrasGroetschelWessaely1997, author = {Alevras, Dimitris and Gr{\"o}tschel, Martin and Wess{\"a}ly, Roland}, title = {Capacity and Survivability Models for Telecommunication Networks}, series = {Proceedings of the EURO XV/INFORMS XXXIV Meeting, Barcelona June 1997}, booktitle = {Proceedings of the EURO XV/INFORMS XXXIV Meeting, Barcelona June 1997}, editor = {Barcel{\´o}, Jaime}, publisher = {Universitat Polit{\`e}cnica de Catalunya}, address = {Barcelona, Spanien}, year = {1997}, language = {en} } @misc{AlexanderFiedler, author = {Alexander, J. C. and Fiedler, Bernold}, title = {Global Decoupling of Coupled Symmetric Oscillators.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-113}, number = {SC-88-03}, abstract = {We model a symmetric system of coupled oscillators as a graph with symmetry group \$\gamma\$. Each vertex of the graph represents an "oscillator" or a "cell" of reactants. The magnitude (concentration) of the reactants in the \$ i \$ th cell is represented by a vector \$ x^i \$. The edges represent the coupling of the cells. The cells are assumed to evolve by identical reaction-diffusion equation which depends on the sum of the reactants in the nearest neighbors. Thus the dynamics of the system is described by a nonlinear differential system \begin{flushleft} \[ \mbox {(*) \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ } \dot{x}^i = f (x^i,\sum_{j \in N_i} x^j), \mbox { \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ } \] \end{flushleft} where the sum ranges over the set \$ N_i \$ of neighbors of cell \$ i \$ . If \$ f \$ also has a symmetry (e.g., oddness), there are geometric conditions on the graph such that the nonlinear system \$ (*) \$ decouples globally into a product flow on certain sums of isotropy subspaces. Thus we may detect higher-dimensional tori of solutions of \$ (*) \$ which are not amenable to other types of analysis. We present a number of examples, such as bipartite graphs, complete graphs, the square, the octahedron, and a 6-dimensional cube.}, language = {en} } @article{AlhaddadFoerstnerGrothetal., author = {Alhaddad, Samer and F{\"o}rstner, Jens and Groth, Stefan and Gr{\"u}newald, Daniel and Grynko, Yevgen and Hannig, Frank and Kenter, Tobias and Pfreundt, F.J. and Plessl, Christian and Schotte, Merlind and Steinke, Thomas and Teich, J. and Weiser, Martin and Wende, Florian}, title = {The HighPerMeshes Framework for Numerical Algorithms on Unstructured Grids}, series = {Concurrency and Computation: Practice and Experience}, volume = {34}, journal = {Concurrency and Computation: Practice and Experience}, number = {14}, doi = {10.1002/cpe.6616}, abstract = {Solving PDEs on unstructured grids is a cornerstone of engineering and scientific computing. Heterogeneous parallel platforms, including CPUs, GPUs, and FPGAs, enable energy-efficient and computationally demanding simulations. In this article, we introduce the HPM C++-embedded DSL that bridges the abstraction gap between the mathematical formulation of mesh-based algorithms for PDE problems on the one hand and an increasing number of heterogeneous platforms with their different programming models on the other hand. Thus, the HPM DSL aims at higher productivity in the code development process for multiple target platforms. We introduce the concepts as well as the basic structure of the HPM DSL, and demonstrate its usage with three examples. The mapping of the abstract algorithmic description onto parallel hardware, including distributed memory compute clusters, is presented. A code generator and a matching back end allow the acceleration of HPM code with GPUs. Finally, the achievable performance and scalability are demonstrated for different example problems.}, language = {en} } @article{AlhaddadFoerstnerGrothetal., author = {Alhaddad, Samer and F{\"o}rstner, Jens and Groth, Stefan and Gr{\"u}newald, Daniel and Grynko, Yevgen and Hannig, Frank and Kenter, Tobias and Pfreundt, Franz-Josef and Plessl, Christian and Schotte, Merlind and Steinke, Thomas and Teich, J{\"u}rgen and Weiser, Martin and Wende, Florian}, title = {HighPerMeshes - A Domain-Specific Language for Numerical Algorithms on Unstructured Grids}, series = {Euro-Par 2020: Parallel Processing Workshops.}, journal = {Euro-Par 2020: Parallel Processing Workshops.}, publisher = {Springer}, doi = {10.1007/978-3-030-71593-9_15}, pages = {185 -- 196}, abstract = {Solving partial differential equations on unstructured grids is a cornerstone of engineering and scientific computing. Nowadays, heterogeneous parallel platforms with CPUs, GPUs, and FPGAs enable energy-efficient and computationally demanding simulations. We developed the HighPerMeshes C++-embedded Domain-Specific Language (DSL) for bridging the abstraction gap between the mathematical and algorithmic formulation of mesh-based algorithms for PDE problems on the one hand and an increasing number of heterogeneous platforms with their different parallel programming and runtime models on the other hand. Thus, the HighPerMeshes DSL aims at higher productivity in the code development process for multiple target platforms. We introduce the concepts as well as the basic structure of the HighPer-Meshes DSL, and demonstrate its usage with three examples, a Poisson and monodomain problem, respectively, solved by the continuous finite element method, and the discontinuous Galerkin method for Maxwell's equation. The mapping of the abstract algorithmic description onto parallel hardware, including distributed memory compute clusters is presented. Finally, the achievable performance and scalability are demonstrated for a typical example problem on a multi-core CPU cluster.}, language = {en} } @misc{AllalenBrehmStueben, author = {Allalen, Mohammed and Brehm, Matthias and St{\"u}ben, Hinnerk}, title = {Performance of Quantum Chromodynamics (QCD) Simulations on the SGI Altix}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-11086}, number = {08-54}, abstract = {We study performance and scaling of the Berlin Quantum Chromodynamics Program (BQCD) on the SGI Altix 4700 at Leibniz Supercomputing Centre (LRZ). We employ different communication methods (MPI, MPI with two OpenMP threads per process, as well as the shmem library) and run the MPI version on the two types of nodes of that machine. For comparison with other machines we made performance measurements on an IBM p690 cluster and a Cray XT4.}, language = {en} } @inproceedings{AllenAnguloGoodaleetal.2002, author = {Allen, Gabrielle and Angulo, Dave and Goodale, Tom and Kielmann, Thilo and Merzky, Andr{\´e} and Nabrzysk, Jarek and Pukacki, Juliusz and Russel, Michael and Radke, Thomas and Seidel, Edward and Shalf, John and Taylor, Ian}, title = {GridLab - Enabling Applications on the Grid: A Progress Report}, series = {Lecture Notes in Computer Science (LNCS)}, volume = {2536}, booktitle = {Lecture Notes in Computer Science (LNCS)}, pages = {39 -- 45}, year = {2002}, language = {en} } @inproceedings{AllenBengerDramlitschetal.2001, author = {Allen, Gabrielle and Benger, Werner and Dramlitsch, Thomas and Goodale, Tom and Hege, Hans-Christian and Lanfermann, Gerd and Merzky, Andr{\´e} and Radke, Thomas and Seidel, Edward}, title = {Cactus Grid Computing: Review of Current Devlopment}, series = {Proceedings of Euro-Par 2001: 7th International Euro-Par Conference on Parallel Processing}, volume = {2150}, booktitle = {Proceedings of Euro-Par 2001: 7th International Euro-Par Conference on Parallel Processing}, editor = {Sakellariou, Rizos and Keane, Jon and Gurd, John and Freeman, Len}, publisher = {Springer Verlag, Berlin Heidelberg 2001}, doi = {10.1007/3-540-44681-8_115}, pages = {817 -- 824}, year = {2001}, language = {en} } @article{AllenBengerDramlitschetal.2001, author = {Allen, Gabrielle and Benger, Werner and Dramlitsch, Thomas and Goodale, Tom and Hege, Hans-Christian and Lanfermann, Gerd and Merzky, Andr{\´e} and Radtke, Thomas and Seidel, Edward and Shalf, John}, title = {Cactus Tools for Grid Applications}, series = {Cluster Computing}, volume = {4}, journal = {Cluster Computing}, number = {3}, doi = {10.1023/A:1011491422534}, pages = {179 -- 188}, year = {2001}, language = {en} } @inproceedings{AllenBengerGoodaleetal.2000, author = {Allen, Gabrielle and Benger, Werner and Goodale, Tom and Hege, Hans-Christian and Lanfermann, Gerd and Merzky, Andr{\´e} and Radke, Thomas and Seidel, Edward and Shalf, John}, title = {The Cactus Code: A Problem Solving Environment for the Grid}, series = {High Performance Distributed Computing (HPDC-2000)}, booktitle = {High Performance Distributed Computing (HPDC-2000)}, doi = {10.1109/HPDC.2000.868657}, pages = {253 -- 260}, year = {2000}, language = {en} } @article{AllenDavisGoodaleetal.2005, author = {Allen, Gabrielle and Davis, K. and Goodale, Tom and Hutanu, Andrei and Kaiser, Hartmut and Kielmann, Thilo and Merzky, Andre and Nieuwpoort, R. and Reinefeld, Alexander and Schintke, Florian and Sch{\"u}tt, Thorsten and Seidel, Edward and Ullmer, Brygg}, title = {The Grid Application Toolkit: Toward Generic and Easy Appliction Programming Interfaces for the Grid}, series = {Procceedings of the IEEE}, volume = {93}, journal = {Procceedings of the IEEE}, number = {3}, publisher = {IEEE Computer Society Press}, doi = {10.1109/JPROC.2004.842755}, pages = {534 -- 550}, year = {2005}, language = {en} } @inproceedings{AllenDramlitschGoodaleetal., author = {Allen, Gabrielle and Dramlitsch, Thomas and Goodale, Tom and Lanfermann, Gerd and Radke, Thomas and Seidel, Edward and Kielmann, Thilo and Verstoep, Kees and Balaton, Zolt{\´a}n and Kacsuk, P{\´e}ter and Szalai, Ferenc and Gehring, J{\"o}rn and Keller, Axel and Streit, Achim and Matyska, Ludek and Ruda, Miroslav and Krenek, Ales and Knipp, Harald and Merzky, Andr{\´e} and Reinefeld, Alexander and Schintke, Florian and Ludwiczak, Bogdan and Nabrzyski, Jarek and Pukacki, Juliusz and Kersken, Hans-Peter and Aloisio, Giovanni and Cafaro, Massimo and Ziegler, Wolfgang and Russell, Michael}, title = {Early experiences with the EGrid testbed}, series = {Proceedings First IEEE/ACM International Symposium on Cluster Computing and the Grid}, booktitle = {Proceedings First IEEE/ACM International Symposium on Cluster Computing and the Grid}, doi = {10.1109/CCGRID.2001.923185}, pages = {130 -- 137}, language = {en} } @article{AllenGoodaleLanfermannetal.1999, author = {Allen, Gabrielle and Goodale, Tom and Lanfermann, Gerd and Seidel, Edward and Benger, Werner and Hege, Hans-Christian and Merzky, Andr{\´e} and Masso, Joan and Shalf, John}, title = {Solving Einstein's Equations on Supercomputers}, series = {IEEE Computer}, journal = {IEEE Computer}, doi = {10.1109/2.809251}, pages = {52 -- 59}, year = {1999}, language = {en} } @article{AllenMerzkyNabrzysketal.2002, author = {Allen, Gabrielle and Merzky, Andr{\´e} and Nabrzysk, Jarek and Seidel, Edward}, title = {GridLab - A Grid Application Toolkit and Testbed}, series = {Future Generation Computer Systems}, volume = {18(8)}, journal = {Future Generation Computer Systems}, pages = {1143 -- 1153}, year = {2002}, language = {en} } @article{AllenPfenningerParczyk, author = {Allen, Peter and Pfenninger, Vincent and Parczyk, Olaf}, title = {Resilience for tight Hamiltonicity}, series = {Combinatorial Theory}, volume = {4}, journal = {Combinatorial Theory}, number = {1}, doi = {10.5070/C64163846}, language = {en} } @inproceedings{AlonsoBinnigPandisetal., author = {Alonso, Gustavo and Binnig, Carsten and Pandis, Ippokratis and Salem, Kenneth and Skrzypczak, Jan and Stutsman, Ryan and Thostrup, Lasse and Wang, Tianzheng and Wang, Zeke and Ziegler, Tobias}, title = {DPI: The Data Processing Interface for Modern Networks}, series = {9th Biennial Conference on Innovative Data Systems Research}, booktitle = {9th Biennial Conference on Innovative Data Systems Research}, abstract = {As data processing evolves towards large scale, distributed platforms, the network will necessarily play a substantial role in achieving efficiency and performance. Increasingly, switches, network cards, and protocols are becoming more flexible while programmability at all levels (aka, software defined networks) opens up many possibilities to tailor the network to data processing applications and to push processing down to the network elements. In this paper, we propose DPI, an interface providing a set of simple yet powerful abstractions flexible enough to exploit features of modern networks (e.g., RDMA or in-network processing) suitable for data processing. Mirroring the concept behind the Message Passing Interface (MPI) used extensively in high-performance computing, DPI is an interface definition rather than an implementation so as to be able to bridge different networking technologies and to evolve with them. In the paper we motivate and discuss key primitives of the interface and present a number of use cases that show the potential of DPI for data-intensive applications, such as analytic engines and distributed database systems.}, language = {en} } @inproceedings{AlonsoSilvaAndrzejaketal.2007, author = {Alonso, Javier and Silva, Luis and Andrzejak, Artur and Torres, Jordi}, title = {High-Available Grid Services through the use of Virtualized Clustering}, series = {IEEE-GRID}, booktitle = {IEEE-GRID}, address = {Austin, USA}, year = {2007}, language = {en} }