TY - GEN ED - COMPASS '18, T1 - Two Approximate Dynamic Programming Algorithms for Managing Complete SIS Networks N2 - Inspired by the problem of best managing the invasive mosquito Aedes albopictus across the 17 Torres Straits islands of Australia, we aim at solving a Markov decision process on large Susceptible-Infected-Susceptible (SIS) networks that are highly connected. While dynamic programming approaches can solve sequential decision-making problems on sparsely connected networks, these approaches are intractable for highly connected networks. Inspired by our case study, we focus on problems where the probability of nodes changing state is low and propose two approximate dynamic programming approaches. The first approach is a modified version of value iteration where only those future states that are similar to the current state are accounted for. The second approach models the state space as continuous instead of binary, with an on-line algorithm that takes advantage of Bellman's adapted equation. We evaluate the resulting policies through simulations and provide a priority order to manage the 17 infested Torres Strait islands. Both algorithms show promise, with the continuous state approach being able to scale up to high dimensionality (50 nodes). This work provides a successful example of how AI algorithms can be designed to tackle challenging computational sustainability problems. Y1 - 2018 SN - 978-1-4503-5816-3 U6 - https://doi.org/10.1145/3209811.3209814 PB - ACM New York, NY, USA ER - TY - JOUR A1 - Hassan, Irtaza A1 - Donati, Luca A1 - Stensitzki, Till A1 - Keller, Bettina G A1 - Heyne, Karsten A1 - Imhof, Petra T1 - The vibrational spectrum of the hydrated alanine-leucine peptide in the amide region from IR experiments and first principles calculations JF - Chemical Physics Letters N2 - We have combined infrared (IR) experiments with molecular dynamics (MD) simulations in solution at finite temperature to analyse the vibrational signature of the small floppy peptide Alanine-Leucine. IR spectra computed from first-principles MD simulations exhibit no distinct differences between conformational clusters of -helix or -sheet-like folds with different orientations of the bulky leucine side chain. All computed spectra show two prominent bands, in good agreement with the experiment, that are assigned to the stretch vibrations of the carbonyl and carboxyl group, respectively. Variations in band widths and exact maxima are likely due to small fluctuations in the backbone torsion angles. Y1 - 2018 U6 - https://doi.org/10.1016/j.cplett.2018.03.026 VL - 698 SP - 227 EP - 233 ER - TY - CHAP A1 - Keller, Bettina G. A1 - Aleksić, Stevan A1 - Donati, Luca T1 - Markov State Models in Drug Design T2 - Biomolecular Simulations in Structure‐Based Drug Discovery N2 - This chapter explains the different ways in which Markov State Models (MSMs) can be helpful in structure-based drug design. MSMs are constructed from the time series of molecular dynamics (MD), which can be generated by classical MD simulations. Several features of the MSMs can be utilized for rational drug design. The discretization of a validated MSM is particularly suited to extract meaningful representatives from the conformational ensemble, because the discretization yields a small number of microstates and mirrors the features of the free energy landscape. Long-lived conformations consist of a set of microstates which show high transition rates within the set and low transition rates to microstates outside of the set. The Bayesian agglomerative clustering engine (BACE) algorithm uses the observed transition counts to extract long-lived conformations from an MSM. By iteratively merging microstates according to the Bayes factor and recalculating the Bayes-factor matrix, the algorithm yields an aggregation of the microstates into long-lived conformations. Y1 - 2018 SN - 1865-0562 U6 - https://doi.org/10.1002/9783527806836.ch4 SP - 67 EP - 86 PB - Wiley-Interscience, Weinheim ER - TY - JOUR A1 - Donati, Luca A1 - Keller, Bettina G. T1 - Girsanov reweighting for metadynamics simulations JF - The Journal of Chemical Physics N2 - Metadynamics is a computational method to explore the phase space of a molecular system. Gaussian functions are added along relevant coordinates on the fly during a molecular-dynamics simulation to force the system to escape from minima in the potential energy function. The dynamics in the resulting trajectory are however unphysical and cannot be used directly to estimate dynamical properties of the system. Girsanov reweighting is a recent method used to construct the Markov State Model (MSM) of a system subjected to an external perturbation. With the combination of these two techniques—metadynamics/Girsanov-reweighting—the unphysical dynamics in a metadynamics simulation can be reweighted to obtain the MSM of the unbiased system. We demonstrate the method on a one-dimensional diffusion process, alanine dipeptide, and the hexapeptide Val-Gly-Val-Ala-Pro-Gly (VGVAPG). The results are in excellent agreement with the MSMs obtained from direct unbiased simulations of these systems. We also apply metadynamics/Girsanov-reweighting to a β-hairpin peptide, whose dynamics is too slow to efficiently explore its phase space by direct simulation Y1 - 2018 U6 - https://doi.org/10.1063/1.5027728 VL - 149 IS - 7 SP - 072335 ER - TY - JOUR A1 - Wakayama, Yuki A1 - Yokoyama, Ryohei A1 - Shinano, Yuji A1 - Wakui, Tetsuya T1 - エネルギー供給システムの設計および運用の階層的関係を考慮した最適化(時間集約によるモデル縮約とその効果) T1 - Optimization of Energy Supply Systems in Consideration of Hierarchical Relationship Between Design and Operation(Model Reduction by Time Aggregation and Its Effect) JF - エネルギー・資源学会第34回エネルギーシステム・経済・環境コンファレンス講演論文集 N2 - A hierarchical mixed-integer linear programming method to solve optimal design problems of energy supply systems efficiently has been proposed. The original problem is solved by dividing it into a relaxed optimal design problem at the upper level and optimal operation problems which are independent of each other at the lower level. In this paper, a method of reducing model by time aggregation is proposed to search design solution candidates efficiently in the relaxed optimal design problem at the upper level. This method is realized only by clustering periods and averaging energy demands for clustered periods, while it guarantees to derive the optimal solution. On one hand, the method may decrease the number of design variables and costraints at the upper level, and thus the computation time at the upper level. On the other hand, it may increase the numbers of generated design solution candidates and solved optimal operation problems, and thus the computation time at both the levels. Though a case study on the optimal design of a cogeneration system, it is clarified how the model reduction is effective to enhance the computation efficiency. Y1 - 2018 SP - 401 EP - 404 ER - TY - JOUR A1 - Wakayama, Yuki A1 - Yokoyama, Ryohei A1 - Shinano, Yuji A1 - Wakui, Tetsuya T1 - 階層的最適化によるエネルギ ー供給システムの最適設計・運用 (期間のクラスタリングに よるモデル縮約とその効果) T1 - Optimal Design and Operation of Energy Supply Systems by Hierarchical Optimization (Model Reduction by Clustering Periods and Its Effect) JF - 日本機械学会関西支部第93期定時総会講演会講演論文集 N2 - Ahierarchical mixed-integer linear programmingmethod has been proposed to solve optimal design problems of energy supply systems efficiently. In this paper, a method of reducing model by clustering periods is proposed to search design solution candidates efficiently in the relaxed optimal design problem at the upper level. This method is realized only by clustering periods and averaging energy demands for clustered periods, while it guarantees to derive the optimal solution. Through acase study on the optimaldesign of a cogeneration system, ti is clarified how the model reduction si effective ot enhance the computation efficiency. Y1 - 2018 SP - 259 EP - 260 ER - TY - CHAP A1 - Kramer, Tobias A1 - Läuter, Matthias T1 - Modelling the inner coma of comet 67P/Churyumov-Gerasimenko T2 - Europlanet Science Congress N2 - Based on about 1 million of pressure measurements around comet 67P/Churyumov-Gerasimenko we reconstruct the gas emission across the entire nucleus. Dust particles are seeded in the gas model and the resulting dust distribution follows a daily pattern which agrees with observations if a uniform dust release across the entire sunlit surface is assumed. Y1 - 2018 VL - 12 SP - EPSC2018-115-1 PB - Europlanet Science Congress ER - TY - CHAP A1 - Läuter, Matthias A1 - Kramer, Tobias A1 - Rubin, Martin A1 - Altwegg, Kathrin T1 - Gas production of comet 67P/Churyumov-Gerasimenko reconstructed from DFMS/COPS data T2 - Europlanet Science Congress N2 - We reconstruct the temporal evolution of surface emissions for the four major gas species H2O, CO2, CO, and O2 emitted during the 2015 apparition of comet 67P/Churyumov-Gerasimenko (67P/C-G). Measurements from the Double Focusing Mass Spectrometer (DFMS) of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the COmet Pressure Sensor (COPS) are used to determine the gas sources on the surface with an inverse gas model for the entire coma. For all species, peak production rates and integrated production rates per orbit are evaluated separately for the northern and the southern hemisphere. Complemented with the total mass production, this allows us to estimate the dust-to-gas ratio of the emitted material. Y1 - 2018 VL - 12 SP - EPSC2018-515-1 PB - Europlanet Science Congress ER - TY - JOUR A1 - Bonami, Pierre A1 - Gleixner, Ambros A1 - Linderoth, Jeff A1 - Misener, Ruth T1 - Designing and Implementing Algorithms for Mixed-Integer Nonlinear Optimization (Dagstuhl Seminar 18081) JF - Dagstuhl Reports N2 - Mathematical models for optimal decisions often require both nonlinear and discrete components. These mixed-integer nonlinear programs (MINLP) may be used to optimize the energy use of large industrial plants, integrate renewable sources into energy networks, design biological and biomedical systems, and address numerous other applications of societal importance. The first MINLP algorithms and software were designed by application engineers. While these efforts initially proved useful, scientists, engineers, and practitioners have realized that a transformational shift in technology will be required for MINLP to achieve its full potential. MINLP has transitioned to a forefront position in computer science, with researchers actively developing MINLP theory, algorithms, and implementations. Even with their concerted effort, algorithms and available software are often unable to solve practically-sized instances of these important models. Current obstacles include characterizing the computability boundary, effectively exploiting known optimization technologies for specialized classes of MINLP, and effectively using logical formulas holistically throughout algorithms. Y1 - 2018 U6 - https://doi.org/10.4230/DagRep.8.2.64 VL - 8 IS - 2 SP - 64 EP - 87 ER - TY - JOUR A1 - Bärmann, Andreas A1 - Martin, Alexander A1 - Pokutta, Sebastian A1 - Schneider, Oskar T1 - An Online-Learning Approach to Inverse Optimization Y1 - 2018 ER - TY - JOUR A1 - Bienenstock, Daniel A1 - Muñoz, Gonzalo A1 - Pokutta, Sebastian T1 - Principled Deep Neural Network Training through Linear Programming N2 - Deep Learning has received significant attention due to its impressive performance in many state-of-the-art learning tasks. Unfortunately, while very powerful, Deep Learning is not well understood theoretically and in particular only recently results for the complexity of training deep neural networks have been obtained. In this work we show that large classes of deep neural networks with various architectures (e.g., DNNs, CNNs, Binary Neural Networks, and ResNets), activation functions (e.g., ReLUs and leaky ReLUs), and loss functions (e.g., Hinge loss, Euclidean loss, etc) can be trained to near optimality with desired target accuracy using linear programming in time that is exponential in the input data and parameter space dimension and polynomial in the size of the data set; improvements of the dependence in the input dimension are known to be unlikely assuming P≠NP, and improving the dependence on the parameter space dimension remains open. In particular, we obtain polynomial time algorithms for training for a given fixed network architecture. Our work applies more broadly to empirical risk minimization problems which allows us to generalize various previous results and obtain new complexity results for previously unstudied architectures in the proper learning setting. Y1 - 2018 ER - TY - THES A1 - Dill, Sabrina T1 - Joint Feature Learning and Classification - Deep Learning for Surgical Phase Detection N2 - In this thesis we investigate the task of automatically detecting phases in surgical workflow in endoscopic video data. For this, we employ deep learning approaches that solely rely on frame-wise visual information, instead of using additional signals or handcrafted features. While previous work has mainly focused on tool presence and temporal information for this task, we reason that additional global information about the context of a frame might benefit the phase detection task. We propose novel deep learning architectures: a convolutional neural network (CNN) based model for the tool detection task only, called Clf-Net, as well as a model which performs joint (context) feature learning and tool classification to incorporate information about the context, which we name Context-Clf-Net. For the phase detection task lower-dimensional feature vectors are extracted, which are used as input to recurrent neural networks in order to enforce temporal constraints. We compare the performance of an online model, which only considers previous frames up to the current time step, to that of an offline model that has access to past and future information. Experimental results indicate that the tool detection task benefits strongly from the introduction of context information, as we outperform both Clf-Net results and stateof-the-art methods. Regarding the phase detection task our results do not surpass state-of-the-art methods. Furthermore, no improvement of using features learned by the Context-Clf-Net is observed in the phase detection task for both online and offline versions Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-81745 ER - TY - THES A1 - Schotte, Merlind T1 - Finite-Elemente-Techniken zur mechanischen Stabilitätsanalyse der Hyomandibula von Rochen N2 - Haie und Rochen sind die einzigen Wirbeltiere, die sich durch ein Knorpelskelett auszeichnen, das mit winzigen mineralisierten Elementen bedeckt ist, die sogenannten Tesserae. Obwohl dieser mineralisierte Knorpel seit hunderten von Millionen Jahren ein charakteristisches Merkmal dieser Tiere ist, ist der funktionelle Vorteil dieses Gewebestruktur bisher unklar geblieben. In dieser Masterarbeit wird diese Struktur mithilfe der Finite-Elemente-Methode(FEM) untersucht, wobei biologische Informationen zu den Muskeln und der geometrischen Gegebenheiten aus einem hochaufgelösten, kontrastgefärbten μCT-Scan einer Stechrochenhyomandibula verwendet werden. Für die Analyse werden Computer-Aided-Design(CAD)-Modelle und FE-Modelle konstruiert sowie vorhandene Methoden erweitert, um bei den Berechnungen die Charakteristika des biologischen Objektes bestmöglich zu berücksichtigen. Die Modelle bauen auf einer Segmentierung der Hyomandibula auf, wobei die mehreren tausend Tesserae in diesem Datensatz bereits voneinander isoliert sind. Für die Modellierung der Hyomandibula wird als erstes ein CAD-Modell konstruiert. Bei dieser Konstruktion wird eine Tesserae-Mittelfläche erstellt und im Anschluss nach innen und außen verschoben. Der nächste Schritt basiert auf dem Einbau von Zwischenwänden, die die Tesserae voneinander separieren. Auf Grundlage dieses Modells wird ein Tetraedergitter generiert, das die Basis für den zweiten Teil dieser Arbeit darstellt - die Berechnungen mit der FEM. Die wesentliche Aufgabe des zweiten Teils beinhaltet die Konstruktion eines FE-Modells, das in die lineare FEM einzuordnen ist. In dieses fließen die Randbedingungen und die Materialeigenschaften des Skelettelements ein. Mithilfe der FEM lassen sich die durch Krafteinwirkung auftretenden Verschiebungen und Spannungen der Hyomandibula ermitteln. Die Ergebnisse geben Rückschlüsse über das Verhalten des Materials, die Besonderheiten der Geometrie und damit über die Stabilität des Objektes. Der dritte Teil der Abschlussarbeit beschäftigt sich mit zusätzlichen Anpassungen und Änderungen der Modelle (CAD-Modell und FE-Modell), um diese Resultate mit dem Modell zu vergleichen, das der Biologie am nächsten kommt. Diese Anpassungen beinhalten das Variieren der Dicke der mineralisierten Schicht, die Konstellation des Materials und den Abstand zwischen den Tesserae. Die Ergebnisse zeigen, dass sowohl die Tesserae-Struktur als auch die zwischen den Tesserae liegenden Kollagenfasern vermutlich keinen Einfluss auf die Mechanik und dementsprechend die Stabilität haben. Jedoch lassen die unterschiedlichen Resultate im Fall verschieden gewählter Tesserae-Dicken annehmen, dass diese sehr wohl einen Einfluss besitzen. N2 - Sharks and rays are the only vertebrates characterized by a peculiar cartilage skeleton covered with minute mineralized tiles called tesserae. Although this tessellated cartilage has been a defining feature of this lineage for hundreds of millions of years, the functional advantage of this tissue design has remained obscure. In this Master’s thesis, the finite element method (FEM) is used to investigate the role of tiling in the skeleton, using biological information on the muscles and shape from a high-resolution, contrast-stained μCT-scan of a stingray hyomandibula. For this purpose, computer aided design (CAD) models and FE models are constructed and existing methods will be extended to take the best possible account of the characteristics of the biological object. The analysis builds from a segmentation of the hyomandibula, with the dataset’s several thousand tesserae pre-isolated from one another. For the modeling of the hyomandibula a CAD model is constructed. In this construction, a medial surface is created using the tesserae which is subsequently moved to the inside and outside. The next step is to integrate partition walls separating the tesserae elements. Based on this model, a tetrahedral grid is then generated, which is the content of the second part of this thesis, the calculation with the FEM. A finite element model is constructed including boundary conditions and material properties of the skeletal element to compute the results using the linear FEM theory. The FEM is used to determine the displacements and stresses resulting from biological forces acting on the hyomandibula. The results allow conclusions of the material behavior, geometric characteristics (tesselation) and therefore the object stability. Important contributions of this thesis are additional adjustments and changes to the models (CAD model and FE model) to make it more appropriate to study the biological data at hand. The tesserae thickness, the length of the collagenious fibres and the constellation of the material are the parameters, which are changed. In contrast to the tesserae thicknesses, the results suggest that both the arrangement of the tesserae and its interposed collagen fibers have no substantial influence on the mechanics. Y1 - 2018 ER - TY - THES A1 - Weltsch, André T1 - Fast Approximation of Equations of transient Gasflow Y1 - 2018 ER - TY - CHAP A1 - Inanlouganji, A. A1 - Pedrielli, G. A1 - Fainekos, G. A1 - Pokutta, Sebastian T1 - Continuous Simulation Optimization with Model Mismatch Using Gaussian Process Regression T2 - Proceedings of the 2018 Winter Simulation Conference Y1 - 2018 ER - TY - CHAP A1 - Pokutta, Sebastian A1 - Singh, M. A1 - Torrico, A. T1 - Efficient algorithms for robust submodular maximization under matroid constraints T2 - ICML Workshop Paper Y1 - 2018 N1 - Additional Note: https://arxiv.org/abs/1807.09405 N1 - URL of the PDF: https://sites.google.com/view/icml2018nonconvex/papers ER - TY - JOUR A1 - Le Bodic, P. A1 - Pfetsch, Marc A1 - Pavelka, J. A1 - Pokutta, Sebastian T1 - Solving MIPs via Scaling-based Augmentation JF - Discrete Optimization Y1 - 2018 N1 - Additional Note: doi: 10.1016/j.disopt.2017.08.004 N1 - URL of the PDF: http://dx.doi.org/10.1016/j.disopt.2017.08.004 VL - 27 SP - 1 EP - 25 ER - TY - JOUR A1 - Braun, Gábor A1 - Roy, Aurko A1 - Pokutta, Sebastian T1 - Stronger Reductions for Extended Formulations JF - to appear in Mathematical Programming B Y1 - 2018 N1 - Additional Note: available at \url{http://arxiv.org/abs/1512.04932} ER - TY - JOUR A1 - Song, R. A1 - Xie, Y. A1 - Pokutta, Sebastian T1 - On the effect of model mismatch for sequential Info-Greedy Sensing JF - EURASIP Journal on Advances in Signal Processing Y1 - 2018 N1 - URL of the PDF: https://asp-eurasipjournals.springeropen.com/articles/10.1186/s13634-018-0551-y ER - TY - CHAP A1 - Paetsch, Olaf T1 - Möglichkeiten und Grenzen automatischer Merkmalserkennung am Beispiel von Risserkennungen in 3D-CT-Aufnahmen von Betonproben N2 - Die Auswertungen der großen Datenmengen moderner bildgebender Verfahren der ZfP können manuell kaum noch bewältigt werden. Hochauflösende 3D-CT-Aufnahmen bestehen oft aus über 1000 Schichtbildern mit einer Datenmenge von mehreren Gigabytes. Aktuelle Computer können diese zwar problemlos visualisieren und erlauben somit eine visuelle Inspektion, aber die möglichst vollständige Erkennung bestimmter Merkmale in den Daten und deren qualitative wie quantitative Auswertung ist durch Experten manuell nicht mehr zu bewältigen. Das gilt insbesondere im Kontext der Schadensaufklärung für die quantitative Analyse verschiedenartig induzierter Risse in Betonen (z.B. durch mechanische Belastungen sowie Frost, Sulfat und Alkali-Kieselsäure-Reaktion). Eine dazu notwendige Segmentierung und Merkmalserkennung kann nur automatisch durchgeführt werden. Dabei ergibt sich (auch fast automatisch) die Frage nach der Verlässlichkeit der verwendeten Algorithmen. Inwieweit kann man davon ausgehen, dass alle gesuchten Merkmale auch tatsächlich gefunden worden sind? Sind die gefundenen Merkmale quantitativ auswertbar und wie wirken sich Parameteränderungen auf die Ergebnisse aus? Sollten immer dieselben, einmal mit gutem Ergebnis angewandten, Parameter auch bei anderen Proben zur besseren Vergleichbarkeit genutzt werden? Anhand eines Risserkennungsalgorithmus basierend auf Formerkennung und Bildverarbeitung wird die Problematik diskutiert. Als Grundlage zur Bewertung des Ansatzes dienen 3D-CT-Aufnahmen von geschädigten Betonprobekörpern und Datensätze, in denen sich aufgrund ihres homogenen Aufbaus mit einfachen Mitteln Risse sicher und eindeutig erkennen lassen. Zur Auswertung der erkannten Risse gehört auch deren Einbettung in das umliegende Material. Das erfordert neben einer automatischen Risserkennung auch eine Segmentierung des gesamten Probekörpers in Zementsteinmatrix, Gesteinskörnung und Porenraum. Da eine solche Segmentierung aufgrund der Datenmenge nur schwer manuell erfolgen kann, werden erste Ergebnisse aus einer Segmentierung mit Hilfe selbstlernender Convolutional Neural Networks gezeigt. Y1 - 2018 PB - iCT 2019 CY - https://www.ndt.net/article/ctc2019/papers/iCT2019_Full_paper_29.pdf ER - TY - JOUR A1 - Chen, Ying A1 - Chua, Wee Song A1 - Koch, Thorsten T1 - Forecasting day-ahead high-resolution natural-gas demand and supply in Germany JF - Applied Energy N2 - Forecasting natural gas demand and supply is essential for an efficient operation of the German gas distribution system and a basis for the operational decisions of the transmission system operators. The German gas market is moving towards more short-term planning, in particular, day-ahead contracts. This increases the difficulty that the operators in the dispatching centre are facing, as well as the necessity of accurate forecasts. This paper presents a novel predictive model that provides day-ahead forecasts of the high resolution gas flow by developing a Functional AutoRegressive model with eXogenous variables (FARX). The predictive model allows the dynamic patterns of hourly gas flows to be described in a wide range of historical profiles, while also taking the relevant determinants data into account. By taking into account a richer set of information, FARX provides stronger performance in real data analysis, with both accuracy and high computational efficiency. Compared to several alternative models in out-of-sample forecasts, the proposed model can improve forecast accuracy by at least 12% and up to 5-fold for one node, 3% to 2-fold and 2-fold to 4-fold for the other two nodes. The results show that lagged 1-day gas flow and nominations are important predictors, and with their presence in the forecast model, temperature becomes insignificant for short-term predictions. Y1 - 2018 U6 - https://doi.org/https://doi.org/10.1016/j.apenergy.2018.06.137 IS - Volume 228 SP - 1091 EP - 1110 ER - TY - THES A1 - Scheizel, Jenia T1 - A fast Flow based Heuristic for MIP modelled SCM Problems Y1 - 2018 ER - TY - JOUR A1 - Berthold, Timo A1 - Farmer, James A1 - Heinz, Stefan A1 - Perregaard, Michael T1 - Parallelization of the FICO Xpress Optimizer JF - Optimization Methods and Software N2 - Computing hardware has mostly thrashed out the physical limits for speeding up individual computing cores. Consequently, the main line of progress for new hardware is growing the number of computing cores within a single CPU. This makes the study of efficient parallelization schemes for computation-intensive algorithms more and more important. A natural precondition to achieving reasonable speedups from parallelization is maintaining a high workload of the available computational resources. At the same time, reproducibility and reliability are key requirements for software that is used in industrial applications. In this paper, we present the new parallelization concept for the state-of-the-art MIP solver FICO Xpress-Optimizer. MIP solvers like Xpress are expected to be deterministic. This inevitably results in synchronization latencies which render the goal of a satisfying workload a challenge in itself. We address this challenge by following a partial information approach and separating the concepts of simultaneous tasks and independent threads from each other. Our computational results indicate that this leads to a much higher CPU workload and thereby to an improved, almost linear, scaling on modern high-performance CPUs. As an added value, the solution path that Xpress takes is not only deterministic in a fixed environment, but also, to a certain extent, thread-independent. This paper is an extended version of Berthold et al. [Parallelization of the FICO Xpress-Optimizer, in Mathematical Software – ICMS 2016: 5th International Conference, G.-M. Greuel, T. Koch, P. Paule, and A. Sommere, eds., Springer International Publishing, Berlin, 2016, pp. 251–258] containing more detailed technical descriptions, illustrative examples and updated computational results. Y1 - 2018 U6 - https://doi.org/10.1080/10556788.2017.1333612 VL - 33 IS - 3 SP - 518 EP - 529 ER - TY - CHAP A1 - Péron, Martin A1 - Bartlett, Peter L. A1 - Becker, Kai-Helge A1 - Helmstedt, Kate A1 - Chadès, Iadine T1 - Two Approximate Dynamic Programming Algorithms for Managing Complete SIS Networks T2 - COMPASS '18 Proceedings of the 1st ACM SIGCAS Conference on Computing and Sustainable Societies N2 - Inspired by the problem of best managing the invasive mosquito Aedes albopictus across the 17 Torres Straits islands of Australia, we aim at solving a Markov decision process on large Susceptible-Infected-Susceptible (SIS) networks that are highly connected. While dynamic programming approaches can solve sequential decision-making problems on sparsely connected networks, these approaches are intractable for highly connected networks. Inspired by our case study, we focus on problems where the probability of nodes changing state is low and propose two approximate dynamic programming approaches. The first approach is a modified version of value iteration where only those future states that are similar to the current state are accounted for. The second approach models the state space as continuous instead of binary, with an on-line algorithm that takes advantage of Bellman's adapted equation. We evaluate the resulting policies through simulations and provide a priority order to manage the 17 infested Torres Strait islands. Both algorithms show promise, with the continuous state approach being able to scale up to high dimensionality (50 nodes). This work provides a successful example of how AI algorithms can be designed to tackle challenging computational sustainability problems. Y1 - 2018 U6 - https://doi.org/10.1145/3209811.3209814 PB - ACM ER - TY - BOOK A1 - Abbink, Erwin A1 - Bärmann, Andreas A1 - Bešinovic, Nikola A1 - Bohlin, Markus A1 - Cacchiani, Valentina A1 - Caimi, Gabrio A1 - de Fabris, Stefano A1 - Dollevoet, Twan A1 - Fischer, Frank A1 - Fügenschuh, Armin A1 - Galli, Laura A1 - Goverde, Rob M.P. A1 - Hansmann, Ronny A1 - Homfeld, Henning A1 - Huisman, Dennis A1 - Johann, Marc A1 - Klug, Torsten A1 - Törnquist Krasemann, Johanna A1 - Kroon, Leo A1 - Lamorgese, Leonardo A1 - Liers, Frauke A1 - Mannino, Carlo A1 - Medeossi, Giorgio A1 - Pacciarelli, Dario A1 - Reuther, Markus A1 - Schlechte, Thomas A1 - Schmidt, Marie A1 - Schöbel, Anita A1 - Schülldorf, Hanno A1 - Stieber, Anke A1 - Stiller, Sebastian A1 - Toth, Paolo A1 - Zimmermann, Uwe ED - Borndörfer, Ralf ED - Klug, Torsten ED - Lamorgese, Leonardo ED - Mannino, Carlo ED - Reuther, Markus ED - Schlechte, Thomas T1 - Handbook of Optimization in the Railway Industry N2 - 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 Y1 - 2018 SN - 978-3-319-72152-1 U6 - https://doi.org/10.1007/978-3-319-72153-8 VL - 268 PB - Springer Verlag ER - TY - CHAP A1 - Berthold, Timo A1 - Perregaard, Michael A1 - Mészáros, Csaba T1 - Four Good Reasons to Use an Interior Point Solver Within a MIP Solver T2 - Kliewer N., Ehmke J., Borndörfer R. (eds) Operations Research Proceedings 2017 N2 - “Interior point algorithms are a good choice for solving pure LPs or QPs, but when you solve MIPs, all you need is a dual simplex” This is the common conception which disregards that an interior point solution provides some unique structural insight into the problem at hand. In this paper, we will discuss some of the benefits that an interior point solver brings to the solution of difficult MIPs within FICO Xpress. This includes many different components of the MIP solver such as branching variable selection, primal heuristics, preprocessing, and of course the solution of the LP relaxation. Y1 - 2018 U6 - https://doi.org/10.1007/978-3-319-89920-6_22 SP - 159 EP - 164 ER - TY - THES A1 - Dill, Sabrina Patricia T1 - Joint Feature Learning and Classification - Deep Learning for Surgical Phase Detection Y1 - 2018 ER - TY - JOUR A1 - Hettich, G. A1 - Schierjott, R. A. A1 - Schilling, C. A1 - Maas, A. A1 - Ramm, Heiko A1 - Bindernagel, Matthias A1 - Lamecker, Hans A1 - Grupp, T. M. T1 - Validation of a Statistical Shape Model for Acetabular Bone Defect Analysis JF - ISTA 2018 London Abstract Book N2 - Acetabular bone defects are still challenging to quantify. Numerous classification schemes have been proposed to categorize the diverse kinds of defects. However, these classification schemes are mainly descriptive and hence it remains difficult to apply them in pre-clinical testing, implant development and pre-operative planning. By reconstructing the native situation of a defect pelvis using a Statistical Shape Model (SSM), a more quantitative analysis of the bone defects could be performed. The aim of this study is to develop such a SSM and to validate its accuracy using relevant clinical scenarios and parameters. Y1 - 2018 ER - TY - GEN A1 - Plöntzke, Julia A1 - Berg, Mascha A1 - Röblitz, Susanna T1 - A mathematical modelling approach to the insight of dynamic networks: Potassium homeostasis and glucose-insulin in dairy cows T2 - ADSA 2018 Annual Meeting N2 - Lactating dairy cows require a particular composition of nutritional ingredients depending on their production status. The optimal supply of energy and minerals in diet, one of them potassium, is indispensable for the prevention of disbalances like hypokalemia or hypoglycaemia. Potassium balance in cows is the result of potassium intake, distribution in the organism, and excretion, and closely interacts with glucose and electrolyte metabolism, in which postpartum veterinary treatments frequently intervene. We present a mechanistic, dynamic model for potassium balance together with a glucose insulin model in non-lactating and lactating dairy cows based on ordinary differential equations. Parameter values were obtained from data of a clinical trial as well as from literature. To verify the mechanistic functioning of the model, we validate the model by comparing simulation outcomes with clinical study findings. Furthermore we perform numerical experiments and compare them with expected behaviour according to mechanistic knowledge. The results give insight into the dynamic behaviour of the network and open the way for further open questions and hypothesis to be tested. Y1 - 2018 UR - https://www.adsa.org/Portals/0/SiteContent/Docs/Meetings/PastMeetings/Annual/2018/223.pdf VL - 101 Suppl. 2 SP - 226 EP - 227 PB - American Dairy Science Association ET - Journal of Dairy Science ER - TY - JOUR A1 - Hendel, Gregor T1 - Adaptive Large Neighborhood Search for Mixed Integer Programming JF - Mathematical Programming Computation N2 - Large Neighborhood Search (LNS) heuristics are among the most powerful but also most expensive heuristics for mixed integer programs (MIP). Ideally, a solver learns adaptively which LNS heuristics work best for the MIP problem at hand in order to concentrate its limited computational budget. To this end, this work introduces Adaptive Large Neighborhood Search (ALNS) for MIP, a primal heuristic that acts a framework for eight popular LNS heuristics such as Local Branching and Relaxation Induced Neighborhood Search (RINS). We distinguish the available LNS heuristics by their individual search domains, which we call neighborhoods. The decision which neighborhood should be executed is guided by selection strategies for the multi armed bandit problem, a related optimization problem during which suitable actions have to be chosen to maximize a reward function. In this paper, we propose an LNS-specific reward function to learn to distinguish between the available neighborhoods based on successful calls and failures. A second, algorithmic enhancement is a generic variable fixing priorization, which ALNS employs to adjust the subproblem complexity as needed. This is particularly useful for some neighborhoods which do not fix variables by themselves. The proposed primal heuristic has been implemented within the MIP solver SCIP. An extensive computational study is conducted to compare different LNS strategies within our ALNS framework on a large set of publicly available MIP instances from the MIPLIB and Coral benchmark sets. The results of this simulation are used to calibrate the parameters of the bandit selection strategies. A second computational experiment shows the computational benefits of the proposed ALNS framework within the MIP solver SCIP. Y1 - 2018 ER - TY - JOUR A1 - Wende, Florian A1 - Marsman, Martijn A1 - Kim, Jeongnim A1 - Vasilev, Fedor A1 - Zhao, Zhengji A1 - Steinke, Thomas T1 - OpenMP in VASP: Threading and SIMD JF - International Journal of Quantum Chemistry N2 - The Vienna Ab initio Simulation Package (VASP) is a widely used electronic structure code that originally exploits process-level parallelism through the Message Passing Interface (MPI) for work distribution within and across nodes. Architectural changes of modern parallel processors urge programmers to address thread- and data-level parallelism as well to benefit most from the available compute resources within a node. We describe for VASP how to approach for an MPI + OpenMP parallelization including data-level parallelism through OpenMP SIMD constructs together with a generic high-level vector coding scheme. We can demonstrate an improved scalability of VASP and more than 20% gain over the MPI-only version, as well as a 2x increased performance of collective operations using the multiple-endpoint MPI feature. The high-level vector coding scheme applied to VASP's general gradient approximation routine gives up 9x performance gain on AVX512 platforms with the Intel compiler. Y1 - 2018 U6 - https://doi.org/10.1002/qua.25851 IS - Emerging Architectures in Computational Chemistry SP - e25851 PB - Wiley Online Library ER - TY - CHAP A1 - Dalitz, Wolfgang A1 - Chrapary, Hagen T1 - Software Products, Software Versions, Archiving of Software, and swMATH T2 - Mathematical Software – ICMS 2018 N2 - Management of software information is difficult for various reasons. First, software typically cannot be reduced to a single object: information about software is an aggregate of software code, APIs, documentation, installations guides, tutorials, user interfaces, test data, dependencies on hardware and other software, etc. Moreover, secondary information about software, especially use cases and experience with employing the software, is important to communicate. Second, typically named software, which we term here a `software product', is taken to stand for all versions of the software which can have different features and properties and may produced different results from the same input data. Software production is a dynamic process and software development is, increasingly, widely distributed. Therefore GitHub, GitLab, Bitbucket and other platforms for sharing are used. Information about software is alos provided in different locations, on websites, repositories, portals, etc. Each resource provides information about software from a particular point of view, but the information is often not linked together. Therefore swMATH has developed a conception which covers portals and a search engines for mathematical software, persistent and citable landing pages for specific software, and a method for software archiving. Based on the publication-based approach, swMATH collects and analyses semi-automatically the existing information about mathematical software found on the Web and makes it available in a user-oriented way. Y1 - 2018 U6 - https://doi.org/10.1007/978-3-319-96418-8_15 SP - 123 EP - 127 ER - TY - CHAP A1 - Dalitz, Wolfgang A1 - Chrapary, Hagen A1 - Sperber, Wolfram T1 - Software Knowledge Management and swMATH T2 - Fachgruppe Didaktik der Mathematik der Universität Paderborn N2 - Mathematische Software ist heute ein weitverbreitetes Werkzeug in der Forschung, aber auch in der mathematischen Bildung. Die Anzahl mathematischer Softwareprodukte wächst, nicht zuletzt durch die Anforderungen der Anwender, stark. Anders als für mathematische Publikationen sind für das Management mathematischer Software viele Fragen offen und werden noch diskutiert, etwa die Standardisierung von Software Zitationen. Der Aufbau einer effizienten Infrastruktur für Software ist eine notwendige Voraussetzung für die Überprüfung von Forschungsergebnissen, die mittels Software erzielt worden sind und wichtig für die Entscheidung, ob eine bestimmte Software zur Lösung eines Problems verwendet werden soll. Das swMATH [1] Portal gibt einen weitgehend vollständigen Überblick über die existierende mathematische Software. Es ist ein Dienst entstanden, der automatisiert die im Web vorhandenen Informationen zu einer Software identifiziert, auswertet und verfügbar macht. Der Dienst soll insbesondere durch die Verknüpfung mit anderen Quellen, etwa dem Internet Archive, persistente Informationen über ein Software Produkt und dessen Versionen liefern. Y1 - 2018 U6 - https://doi.org/10.17877/DE290R-19281 SP - 401 EP - 404 ER - TY - CHAP A1 - Yokoyama, Ryohei A1 - Shinano, Yuji A1 - Wakayama, Yuki A1 - Wakui, Tetsuya T1 - Model Reduction by Time Aggregation for Optimal Design of Energy Supply Systems by an MILP Hierarchical Branch and Bound Method T2 - Proceedings of the 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 2018) N2 - Mixed-integer linear programming (MILP) methods have been applied widely to optimal design of energy supply systems. A hierarchical MILP method has been proposed to solve such optimal design problems effi- ciently. An original problem has been solved by dividing it into a relaxed optimal design problem at the upper level and optimal operation problems which are independent of one another at the lower level. In addition, some strategies have been proposed to enhance the computation efficiency furthermore. In this paper, a method of reducing model by time aggregation is proposed as a novel strategy to search design candidates efficiently in the relaxed optimal design problem at the upper level. In addition, the previous strategies are modified in accordance with the novel strategy. This method is realized only by clustering periods and averaging energy demands for clustered periods, while it guarantees to derive the optimal solu- tion. The method can decrease the number of design variables and constraints at the upper level, and thus may decrease the computation time at the upper level. Through a case study on the optimal design of a gas turbine cogeneration system, it is clarified how the model reduction is effective to enhance the computation efficiency in comparison and combination with the modified previous strategies. Y1 - 2018 ER - TY - CHAP A1 - Yokoyama, Ryohei A1 - Shinano, Yuji A1 - Wakayamaa, Yuji A1 - Wakui, Tetsuya T1 - Optimal Design of a Gas Turbine Cogeneration Plant by a Hierarchical Optimization Method With Parallel Computing T2 - ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition N2 - To attain the highest performance of energy supply systems, it is necessary to rationally determine types, capacities, and numbers of equipment in consideration of their operational strategies corresponding to seasonal and hourly variations in energy demands. Mixed-integer linear programming (MILP) approaches have been applied widely to such optimal design problems. The authors have proposed a MILP method utilizing the hierarchical relationship between design and operation variables to solve the optimal design problems of energy supply systems efficiently. In addition, some strategies to enhance the computation efficiency have been adopted: bounding procedures at both the levels and ordering of the optimal operation problems at the lower level. In this paper, as an additional strategy to enhance the computation efficiency, parallel computing is adopted to solve multiple optimal operation problems in parallel at the lower level. In addition, the effectiveness of each and combinations of the strategies adopted previously and newly is investigated. This hierarchical optimization method is applied to an optimal design of a gas turbine cogeneration plant, and its validity and effectiveness are clarified through some case studies. Y1 - 2018 UR - http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2700845 VL - 3 ER - TY - CHAP A1 - Anderson, Daniel A1 - Hendel, Gregor A1 - Le Bodic, Pierre A1 - Viernickel, Jan Merlin T1 - Clairvoyant Restarts in Branch-and-Bound Search Using Online Tree-Size Estimation T2 - AAAI-19: Proceedings of the Thirty-Third AAAI Conference on Artificial Intelligence N2 - We propose a simple and general online method to measure the search progress within the branch-and-bound algorithm, from which we estimate the size of the remaining search tree. We then show how this information can help solvers algorithmically at runtime by designing a restart strategy for Mixed-Integer Programming (MIP) solvers that decides whether to restart the search based on the current estimate of the number of remaining nodes in the tree. We refer to this type of algorithm as clairvoyant. Our clairvoyant restart strategy outperforms a state-of-the-art solver on a large set of publicly available MIP benchmark instances. It is implemented in the MIP solver SCIP and will be available in future releases. Y1 - 2018 ER - TY - JOUR A1 - Zhang, Wei A1 - Hartmann, Carsten A1 - von Kleist, Max T1 - Optimal control of Markov jump processes: Asymptotic analysis, algorithms and applications to the modeling of chemical reaction systems JF - Communications in Mathematical Sciences N2 - Markov jump processes are widely used to model natural and engineered processes. In the context of biological or chemical applications one typically refers to the chemical master equation (CME), which models the evolution of the probability mass of any copy-number combination of the interacting particles. When many interacting particles (“species”) are considered, the complexity of the CME quickly increases, making direct numerical simulations impossible. This is even more problematic when one aims at controlling the Markov jump processes defined by the CME. In this work, we study both open loop and feedback optimal control problems of the Markov jump processes in the case that the controls can only be switched at fixed control stages. Based on Kurtz’s limit theorems, we prove the convergence of the respective control value functions of the underlying Markov decision problem as the copy numbers of the species go to infinity. In the case of the optimal control problem on a finite time-horizon, we propose a hybrid control policy algorithm to overcome the difficulties due to the curse of dimensionality when the copy number of the involved species is large. Two numerical examples demonstrate the suitability of both the analysis and the proposed algorithms. Y1 - 2018 U6 - https://doi.org/10.4310/CMS.2018.v16.n2.a1 SP - 293 EP - 331 ER - TY - JOUR A1 - Deuflhard, Peter T1 - The Grand Four. Affine Invariant Globalizations of Newton's Method JF - Vietnam Journal of Mathematics Y1 - 2018 U6 - https://doi.org/10.1007/s10013-018-0301-3 VL - 46 IS - 4 SP - 761 EP - 777 ER - TY - JOUR A1 - Lorenz-Spreen, Philipp A1 - Wolf, Frederik A1 - Braun, Jonas A1 - Ghoshal, Gourab A1 - Djurdjevac Conrad, Natasa A1 - Hövel, Philipp T1 - Tracking online topics over time: understanding dynamic hashtag communities JF - Computational Social Networks N2 - Background: Hashtags are widely used for communication in online media. As a condensed version of information, they characterize topics and discussions. For their analysis, we apply methods from network science and propose novel tools for tracing their dynamics in time-dependent data. The observations are characterized by bursty behaviors in the increases and decreases of hashtag usage. These features can be reproduced with a novel model of dynamic rankings. Hashtag communities in time: We build temporal and weighted co-occurrence networks from hashtags. On static snapshots, we infer the community structure using customized methods. On temporal networks, we solve the bipartite matching problem of detected communities at subsequent timesteps by taking into account higher-order memory. This results in a matching protocol that is robust toward temporal fluctuations and instabilities of the static community detection. The proposed methodology is broadly applicable and its outcomes reveal the temporal behavior of online topics. Modeling topic-dynamics: We consider the size of the communities in time as a proxy for online popularity dynamics. We find that the distributions of gains and losses, as well as the interevent times are fat-tailed indicating occasional, but large and sudden changes in the usage of hashtags. Inspired by typical website designs, we propose a stochastic model that incorporates a ranking with respect to a time-dependent prestige score. This causes occasional cascades of rank shift events and reproduces the observations with good agreement. This offers an explanation for the observed dynamics, based on characteristic elements of online media. Y1 - 2018 U6 - https://doi.org/10.1186/s40649-018-0058-6 VL - 5 IS - 9 ER - TY - JOUR A1 - Agudo Jácome, Leonardo A1 - Hege, Hans-Christian A1 - Paetsch, Olaf A1 - Pöthkow, Kai T1 - Three-dimensional reconstruction and quantification of dislocation substructures from transmission electron microscopy stereo pairs JF - Ultramicroscopy N2 - 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. Y1 - 2018 U6 - https://doi.org/10.1016/j.ultramic.2018.08.015 VL - 195 SP - 157 EP - 170 ER - TY - THES A1 - Helfmann, Luzie T1 - Stochastic Modeling of Interacting Agent Systems Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-71887 ER - TY - JOUR A1 - Kork, F. A1 - Spies, Claudia A1 - Conrad, Tim A1 - Weiss, B. A1 - Roenneberg, T. A1 - Wernecke, K.-D. A1 - Balzer, Felix T1 - Associations of postoperative mortality with the time of day, week and year JF - Anaesthesia Y1 - 2018 ER - TY - JOUR A1 - Obermeier, Patrick A1 - Heim, A. A1 - Biere, Barbara A1 - Hage, E. A1 - Alchikh, Maren A1 - Conrad, Tim A1 - Schweiger, Brunhilde A1 - Rath, Barbara T1 - Clinical characteristics and disease severity associated with adenovirus infections in infants and children - discovery of a novel adenovirus, HAdV-D80 JF - Clinical Infectious Diseases Y1 - 2018 ER - TY - THES A1 - Anderson, Lovis T1 - The Computation of the Volume of the Union of Polytopes via a Sweep-Plane Algorithm N2 - Das Thema dieser Arbeit ist ein Volumen-Algorithmus für die Vereinigung von Polytopen. Der Algorithmus basiert auf der Arbeit von Bieri und Nef. Er berechnet das Volumen der Vereinigung von Polytopen mit einem Sweep-Verfahren. Dabei wird eine Hyperebene im Raum verschoben und das Volumen auf der einen Seite der Hyperebene berechnet. Umso weiter die Hyperebene verschobe wird, desto größer ist auch der Halbraum. Unser Algorithmus berechnet das Volumen einer Vereinigung von Polytopen geschnitten mit dem Halbraum der Sweep-Ebene als eine Funktion abhängig von der Veschiebung. Ab einem gewissen Punkt liegt der Körper dabei komplett im Halbraum der Sweep-Ebene und das Volumen bleibt konstant. Unser Algorithmus unterscheidet sich in zwei Punkten von dem Algorithmus von Bieri und Nef. Erstens funktioniert er nur auf der Vereinigung von Polytopen, wohingegen der Algorithmus von Bieri und Nef für Nef-Polyeder funktioniert. Diese sind eine Verallgemeinerung von Polyedern, die auch die Klasse der Vereinigung von Polytopen umfasst. Für uns ist das allerdings kein Nachteil, da unsere Datensätze zu Vereinigungen von Polytopen führen. Zweitens ist unser Algorithmus in zwei Teile aufgeteilt. Im ersten Teil wird eine Datenstruktur entwickelt, aus der im zweiten Teil zusammen mit einer Richtung die Sweep-Ebenen-Volumenfunktion berechnet wird. Der Großteil der Komplexität liegt im ersten Teil des Algorithmus. Das hat den Vorteil, dass wir die Volumenfunktionen für viele verschiedene Richtungen berechnen können. So können Einblicke in die Struktur des Körpers gewonnen werden. Der Algorithmus beruht auf zwei verschiedenen Zerlegungsansätzen. Zuerst können wir mit Hilfe von Anordnungen von Hyperebenen eine Vereinigung von Polytopen in ihre Zellen zerlegen. Dabei berufen wir uns auf die Arbeit von Gerstner und Holtz, in der das Konzept der Positionsvektoren eingeführt wird. Diese nutzen wir um die Ecken und ihre benachbarten Zellen zu bestimmen. So erhalten wir eine Zerlegung unserer Vereinigung in Zellen, deren paarweise Schnitte kein Volumen haben. Das zweite Zerlegungskonzept ist die konische Zerlegung, wie sie von Lawrence eingeführt wurde. Mit Hilfe dieser können wir die Indikatorfunktion eines Polytops als die Summe der Indikatorfunktionen seiner Vorwärtskegel schreiben. Die Sweep-Ebenen Volumenfunktionen können dann leicht mit Hilfe einer altbekannten Formel für das Volumen von Simplices berechnet werden. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-71829 ER - TY - JOUR A1 - Dartsch, Maria A1 - Dulski, Sebastian A1 - Engels, Frauke A1 - Gran, Meike A1 - Kende, Jiri A1 - Lohrum, Stefan A1 - Porth, Robert A1 - Ristau, Ute A1 - Rüter, Christian A1 - Sabisch, Andreas A1 - Stumm, Birgit A1 - Taylor, Viola A1 - Voß, Michael T1 - Einführung des cloudbasierten Bibliothekssystems Alma in Berlin – ein Erfahrungsbericht JF - ABI Technik - Zeitschrift für Automation, Bau und Technik im Archiv-, Bibliotheks- und Informationswesen N2 - Die enge Zusammenarbeit der vier Berliner Universitätsbibliotheken1 reicht weit zurück. Bereits vor der Jahrtausendwende haben die Berliner Universitätsbibliotheken (UBs) gemeinsam das Bibliothekssystem Aleph 500 ausgewählt und implementiert, danach folgten weitere Systeme – das Linking System SFX, die Digitale Bibliothek MetaLib und das Bibliotheksportal Primo. Es war daher folgerichtig und selbstverständlich, dass auch die Auswahl und Implementierung eines neuen Bibliothekssystems in enger Abstimmung und Zusammenarbeit erfolgte. Die Erfahrungen bei Vertragsverhandlungen und Implementierung von Alma sind Gegenstand des folgenden Berichtes. N2 - As regards implementing new library technology, the Berlin University libraries have been working closely together for more than 20 years. It was the case for the implementation of the legacy system Aleph 500, the linking system SFX, the digital library MetaLib and the library portal Primo, and therefore it was a matter of course to continue the close cooperation during the implementation of the new cloud-based library system, too. The experience gained during the contract negotiations and the implementation project, and lessons learned are the focus of this report. Y1 - 2018 U6 - https://doi.org/10.1515/abitech-2018-2002 VL - 38 IS - 2 SP - 128 EP - 141 ER - TY - THES A1 - Elijazyfer, Ziena T1 - Längenbeschränkte Teilgraphenbildung zur Maut-Kontrollstreckenoptimierung Y1 - 2018 ER - TY - THES A1 - Schreck, Vanessa T1 - Algorithmic Analysis of the Graph Segmentation Problem Y1 - 2018 ER - TY - THES A1 - Villatoro, José T1 - A combined approach for the analysis of biomolecules using IR-MALDI ion mobility spectrometry and molecular dynamics simulations of peptide ions in the gas phase Y1 - 2018 ER - TY - THES A1 - Klimm, Martina T1 - New Strategies in Conformation Dynamics Y1 - 2018 ER - TY - THES A1 - Quer, Jannes T1 - Importance Sampling for metastable dynamical systems in molecular dynamics Y1 - 2018 ER -