@inproceedings{17651, abstract = {{Consider mitigating the effects of denial of service or of malicious traffic in networks by deleting edges. Edge deletion reduces the DoS or the number of the malicious flows, but it also inadvertently removes some of the desired flows. To model this important problem, we formulate two problems: (1) remove all the undesirable flows while minimizing the damage to the desirable ones and (2) balance removing the undesirable flows and not removing too many of the desirable flows. We prove these problems are equivalent to important theoretical problems, thereby being important not only practically but also theoretically, and very hard to approximate in a general network. We employ reductions to nonetheless approximate the problem and also provide a greedy approximation. When the network is a tree, the problems are still MAX SNP-hard, but we provide a greedy-based 2l-approximation algorithm, where l is the longest desirable flow. We also provide an algorithm, approximating the first and the second problem within {\$}{\$}2 {\backslash}sqrt{\{} 2{\backslash}left| E {\backslash}right| {\}}{\$}{\$}and {\$}{\$}2 {\backslash}sqrt{\{}2 ({\backslash}left| E {\backslash}right| + {\backslash}left| {\backslash}text {\{}undesirable flows{\}} {\backslash}right| ){\}}{\$}{\$}, respectively, where E is the set of the edges of the network. We also provide a fixed-parameter tractable (FPT) algorithm. Finally, if the tree has a root such that every flow in the tree flows on the path from the root to a leaf, we solve the problem exactly using dynamic programming.}}, author = {{Polevoy, Gleb and Trajanovski, Stojan and Grosso, Paola and de Laat, Cees}}, booktitle = {{Combinatorial Optimization and Applications}}, editor = {{Kim, Donghyun and Uma, R. N. and Zelikovsky, Alexander}}, isbn = {{978-3-030-04651-4}}, keywords = {{flow, Red-Blue Set Cover, Positive-Negative Partial Set Cover, approximation, tree, MAX SNP-hard, root, leaf, dynamic programming, FPT}}, pages = {{217--232}}, publisher = {{Springer International Publishing}}, title = {{{Removing Undesirable Flows by Edge Deletion}}}, year = {{2018}}, } @article{23626, abstract = {{Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation’s alkyl chain length n from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present here such a study of the liquid–air interface for n=2to 22, using angstrom-resolution X-ray methods. For n<6, a typical “simple liquid” monotonic surface-normal electron density profile ρe(z) is obtained, like those of water and organic solvents. For n>6, increasingly more pronounced nanoscale self-segregation of the molecules’ charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear n dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For n=22, a different surface phase is observed above melting. Our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk–surface structure relations.}}, author = {{Haddad, Julia and Pontoni, Diego and Murphy, Bridget M. and Festersen, Sven and Runge, Benjamin and Magnussen, Olaf M. and Steinrück, Hans-Georg and Reichert, Harald and Ocko, Benjamin M. and Deutsch, Moshe}}, issn = {{0027-8424}}, journal = {{Proceedings of the National Academy of Sciences}}, pages = {{E1100--E1107}}, title = {{{Surface structure evolution in a homologous series of ionic liquids}}}, doi = {{10.1073/pnas.1716418115}}, volume = {{115}}, year = {{2018}}, } @article{22117, author = {{Schramm, B. and Risse, L. and Brüggemann, J.P. and Richard, H.A. and Kullmer, G.}}, journal = {{Journal of 3D Printing in medicine}}, title = {{{Additive manufacturing for medical applications}}}, volume = {{2}}, year = {{2018}}, } @inproceedings{22145, abstract = {{results clearly demonstrate the great potential of additive}}, author = {{Joy, T.D. and Brüggemann, J.P. and Kullmer, G.}}, booktitle = {{Procedia Structural Integrity}}, pages = {{in press}}, title = {{{Crack Growth Simulation with Adapcrack3D in 3D Structures under the influence of Temperature}}}, year = {{2018}}, } @inproceedings{22147, author = {{Brüggemann, J.P. and Risse, L. and Kullmer, G. and Schramm, B. and Richard, H.A.}}, booktitle = {{Procedia Structural Integrity}}, pages = {{in press}}, title = {{{Optimization of the fracture mechanical properties of additively manufactured EN AW-7075}}}, doi = {{10.1016/j.prostr.2018.12.052}}, year = {{2018}}, } @inproceedings{22759, author = {{Albers, Alexander and Bernijazov, Ruslan and Kaiser, Lydia and Dumitrescu, Roman}}, booktitle = {{IEEE - 13th System of Systems Engineering Conference, 19. - 22. Jun. 2018}}, title = {{{Internet of Things Canvas for Ideation in Model-Based Product Generation Planning}}}, year = {{2018}}, } @inproceedings{22786, author = {{Joppen, Robert and von Enzberg, Sebastian and Kühn, Arno and Dumitrescu, Roman}}, booktitle = {{The 16th Global Conference on Sustainable Manufacturing }}, title = {{{A practical Framework for the Optimization of Production Management Processes}}}, year = {{2018}}, } @inproceedings{5675, abstract = {{When responding to natural disasters, professional relief units are often supported by many volunteers which are not affiliated to humanitarian organizations. The effective coordination of these volunteers is crucial to leverage their capabilities and to avoid conflicts with professional relief units. In this paper, we empirically identify key requirements that professional relief units pose on this coordination. Based on these requirements, we suggest a decision model. We computationally solve a real-world instance of the model and empirically validate the computed solution in interviews with practitioners. Our results show that the suggested model allows for solving volunteer coordination tasks of realistic size near-optimally within short time, with the determined solution being well accepted by practitioners. We also describe in this article how the suggested decision support model is integrated in the volunteer coordination system which we develop in joint cooperation with a disaster management authority and a software development company.}}, author = {{Rauchecker, Gerhard and Schryen, Guido}}, booktitle = {{Proceedings of the 15th International Conference on Information Systems for Crisis Response and Management}}, keywords = {{Coordination of spontaneous volunteers, volunteer coordination system, decision support, scheduling optimization model, linear programming}}, location = {{Rochester, NY, USA}}, title = {{{Decision Support for the Optimal Coordination of Spontaneous Volunteers in Disaster Relief}}}, year = {{2018}}, } @inproceedings{5822, author = {{Gaspers, Daniel and Knorr, Christoph and Nickchen, Tobias and Nickchen, Daniel and Mertsching, Barbel and Mohamed, Mahmoud A.}}, booktitle = {{2018 IEEE International Symposium on Safety, Security, and Rescue Robotics (SSRR)}}, isbn = {{9781538655726}}, publisher = {{IEEE}}, title = {{{Real-time Graph-Based 3D Reconstruction of Sparse Feature Environments for Mobile Robot Applications}}}, doi = {{10.1109/ssrr.2018.8468658}}, year = {{2018}}, } @inproceedings{8750, abstract = {{In this article we propose a descent method for equality and inequality constrained multiobjective optimization problems (MOPs) which generalizes the steepest descent method for unconstrained MOPs by Fliege and Svaiter to constrained problems by using two active set strategies. Under some regularity assumptions on the problem, we show that accumulation points of our descent method satisfy a necessary condition for local Pareto optimality. Finally, we show the typical behavior of our method in a numerical example.}}, author = {{Gebken, Bennet and Peitz, Sebastian and Dellnitz, Michael}}, booktitle = {{Numerical and Evolutionary Optimization – NEO 2017}}, isbn = {{9783319961033}}, issn = {{1860-949X}}, title = {{{A Descent Method for Equality and Inequality Constrained Multiobjective Optimization Problems}}}, doi = {{10.1007/978-3-319-96104-0_2}}, year = {{2018}}, } @article{8751, abstract = {{Multiobjective optimization plays an increasingly important role in modern applications, where several criteria are often of equal importance. The task in multiobjective optimization and multiobjective optimal control is therefore to compute the set of optimal compromises (the Pareto set) between the conflicting objectives. The advances in algorithms and the increasing interest in Pareto-optimal solutions have led to a wide range of new applications related to optimal and feedback control, which results in new challenges such as expensive models or real-time applicability. Since the Pareto set generally consists of an infinite number of solutions, the computational effort can quickly become challenging, which is particularly problematic when the objectives are costly to evaluate or when a solution has to be presented very quickly. This article gives an overview of recent developments in accelerating multiobjective optimal control for complex problems where either PDE constraints are present or where a feedback behavior has to be achieved. In the first case, surrogate models yield significant speed-ups. Besides classical meta-modeling techniques for multiobjective optimization, a promising alternative for control problems is to introduce a surrogate model for the system dynamics. In the case of real-time requirements, various promising model predictive control approaches have been proposed, using either fast online solvers or offline-online decomposition. We also briefly comment on dimension reduction in many-objective optimization problems as another technique for reducing the numerical effort.}}, author = {{Peitz, Sebastian and Dellnitz, Michael}}, issn = {{2297-8747}}, journal = {{Mathematical and Computational Applications}}, number = {{2}}, title = {{{A Survey of Recent Trends in Multiobjective Optimal Control—Surrogate Models, Feedback Control and Objective Reduction}}}, doi = {{10.3390/mca23020030}}, volume = {{23}}, year = {{2018}}, } @inbook{8754, abstract = {{In this chapter, we combine a global, derivative-free subdivision algorithm for multiobjective optimization problems with a posteriori error estimates for reduced-order models based on Proper Orthogonal Decomposition in order to efficiently solve multiobjective optimization problems governed by partial differential equations. An error bound for a semilinear heat equation is developed in such a way that the errors in the conflicting objectives can be estimated individually. The resulting algorithm constructs a library of locally valid reduced-order models online using a Greedy (worst-first) search. Using this approach, the number of evaluations of the full-order model can be reduced by a factor of more than 1000.}}, author = {{Beermann, Dennis and Dellnitz, Michael and Peitz, Sebastian and Volkwein, Stefan}}, booktitle = {{Reduced-Order Modeling (ROM) for Simulation and Optimization}}, isbn = {{9783319753188}}, pages = {{47--72}}, title = {{{Set-Oriented Multiobjective Optimal Control of PDEs Using Proper Orthogonal Decomposition}}}, doi = {{10.1007/978-3-319-75319-5_3}}, year = {{2018}}, } @inproceedings{9999, abstract = {{Ultrasonic wire bonding is an indispensable process in the industrial manufacturing of semiconductor devices. Copper wire is increasingly replacing the well-established aluminium wire because of its superior electrical, thermal and mechanical properties. Copper wire processes differ significantly from aluminium processes and are more sensitive to disturbances, which reduces the range of parameter values suitable for a stable process. Disturbances can be compensated by an adaption of process parameters, but finding suitable parameters manually is difficult and time-consuming. This paper presents a physical model of the ultrasonic wire bonding process including the friction contact between tool and wire. This model yields novel insights into the process. A prototype of a multi-objective optimizing bonding machine (MOBM) is presented. It uses multi-objective optimization, based on the complete process model, to automatically select the best operating point as a compromise of concurrent objectives.}}, author = {{Unger, Andreas and Hunstig, Matthias and Meyer, Tobias and Brökelmann, Michael and Sextro, Walter}}, booktitle = {{In Proceedings of IMAPS 2018 – 51st Symposium on Microelectronics, Pasadena, CA, 2018}}, keywords = {{wire bonding, multi-objective optimization, process model, copper wire, self-optimization}}, title = {{{Intelligent Production of Wire Bonds using Multi-Objective Optimization – Insights, Opportunities and Challenges}}}, doi = {{10.4071/2380-4505-2018.1.000572}}, volume = {{Vol. 2018, No. 1, pp. 000572-000577.}}, year = {{2018}}, } @inproceedings{3930, author = {{Brassat, Katharina and Taube, A. and Kool, Daniel and Tasche, L. and Hoyer, K.P. and Schaper, Mirko and Lindner, Jörg}}, location = {{Warsaw, Poland}}, title = {{{Ti-6Al-4V alloy: 3D printing of lightweight implants and nanopatterning by self-assembly}}}, year = {{2018}}, } @article{669, abstract = {{We study a new class of games which generalizes congestion games andits bottleneck variant. We introduce congestion games with mixed objectives to modelnetwork scenarios in which players seek to optimize for latency and bandwidths alike.We characterize the (non-)existence of pure Nash equilibria (PNE), the convergenceof improvement dynamics, the quality of equilibria and show the complexity of thedecision problem. For games that do not possess PNE we give bounds on the approx-imation ratio of approximate pure Nash equilibria.}}, author = {{Feldotto, Matthias and Leder, Lennart and Skopalik, Alexander}}, issn = {{1382-6905}}, journal = {{Journal of Combinatorial Optimization}}, number = {{4}}, pages = {{1145--1167}}, publisher = {{Springer Nature}}, title = {{{Congestion games with mixed objectives}}}, doi = {{10.1007/s10878-017-0189-y}}, volume = {{36}}, year = {{2018}}, } @inproceedings{6970, abstract = {{Dynamic allocation of resources is a key feature in network function virtualization (NFV), enabling flexible adjustment of slices and contained network services to ever-changing service demands. Considering resource allocation across the entire network, many authors have proposed approaches to optimize the placement and chaining of virtual network function (VNF) instances and the allocation of resources to these VNF instances. In doing so, various optimization objectives are conceivable, e.g., minimizing certain required resources or the end-to-end delay of the placed services. In this paper, we investigate the relationship between four typical optimization objectives when coordinating the placement and resource allocation of chained VNF instances. We observe an interesting trade-off between minimizing the overhead of starting/stopping VNF instances and all other objectives when adapting to changed service demands.}}, author = {{Schneider, Stefan Balthasar and Dräxler, Sevil and Karl, Holger}}, booktitle = {{IEEE Global Communications Conference (GLOBECOM 2018)}}, location = {{Abu Dhabi, UAE}}, publisher = {{IEEE}}, title = {{{Trade-offs in Dynamic Resource Allocation in Network Function Virtualization}}}, year = {{2018}}, } @inproceedings{16425, abstract = {{In recent years, OpenCL has been increasingly adopted as it enables software programmers to harness the performance and power efficiency of FPGAs. Despite simplifying the FPGA programming challenge, achieving high performance and energy efficiency with OpenCL is still a difficult task. In order to further contribute to the advance of the OpenCL usage for FPGAs, we utilize a realistic application scenario as our case study: the AutoDock molecular docking software. While OpenCL has proven its effectiveness in accelerating molecular docking on GPUs, for FPGA-based AutoDock accelerators it struggles with difficult design patterns. Besides complex multiple-producers to single-consumer datapaths, these include time-intensive loops with variable runtimes. Therefore, this work presents the design and optimization steps for implementing AutoDock in OpenCL targeting an Arria-10 FPGA, as well as a corresponding execution runtime and energy-efficiency evaluation. Applying these techniques improved the performance of the initial OpenCL implementation for FPGAs by three orders of magnitude, with the final version of the code now yielding speed-ups of up to ~2.7x, and energy-efficiency gains of up to ~1.8x over the original serial AutoDock version executing on a current-generation CPU.}}, author = {{Solis-Vasquez, Leonardo and Koch, Andreas}}, booktitle = {{FSP Workshop 2018; Fifth International Workshop on FPGAs for Software Programmers}}, keywords = {{pc2-harp-ressources}}, pages = {{1--10}}, title = {{{A Case Study in Using OpenCL on FPGAs: Creating an Open-Source Accelerator of the AutoDock Molecular Docking Software}}}, year = {{2018}}, } @inproceedings{1181, abstract = {{The main idea in On-The-Fly Computing is to automatically compose existing software services according to the wishes of end-users. However, since user requirements are often ambiguous, vague and incomplete, the selection and composition of suitable software services is a challanging task. In this paper, we present our current approach to improve requirement descriptions before they are used for software composition. This procedure is fully automated, but also has limitations, for example, if necessary information is missing. In addition, and in response to the limitations, we provide insights into our above-mentioned current work that combines the existing optimization approach with a chatbot solution.}}, author = {{Bäumer, Frederik Simon and Geierhos, Michaela}}, booktitle = {{Joint Proceedings of REFSQ-2018 Workshops, Doctoral Symposium, Live Studies Track, and Poster Track co-located with the 23rd International Conference on Requirements Engineering: Foundation for Software Quality (REFSQ 2018)}}, editor = {{Schmid, Klaus and Spoletini, Paola and Ben Charrada, Eya and Chisik, Yoram and Dalpiaz, Fabiano and Ferrari, Alessio and Forbrig, Peter and Franch, Xavier and Kirikova, Marite and Madhavji, Nazim and Palomares, Cristina and Ralyté, Jolita and Sabetzadeh, Mehrdad and Sawyer, Pete and van der Linden, Dirk and Zamansky, Anna}}, issn = {{1613-0073}}, location = {{Utrecht, The Netherlands}}, publisher = {{CEUR-WS.org}}, title = {{{How to Deal with Inaccurate Service Requirements? Insights in Our Current Approach and New Ideas}}}, volume = {{2075}}, year = {{2018}}, } @inproceedings{15585, author = {{Bednarik, Roman and Schulte, Carsten and Budde, Lea and Heinemann, Birte and Vrzakova, Hana}}, booktitle = {{Proceedings of the 18th Koli Calling International Conference on Computing Education Research, Koli, Finland, November 22-25, 2018}}, pages = {{2:1--2:8}}, title = {{{Eye-movement Modeling Examples in Source Code Comprehension: A Classroom Study}}}, doi = {{10.1145/3279720.3279722}}, year = {{2018}}, } @inbook{14856, author = {{Hallmann, Corinna and Burmeister, Sascha Christian and Wissing, Michaela and Suhl, Leena}}, booktitle = {{Communications in Computer and Information Science}}, isbn = {{9783319962702}}, issn = {{1865-0929}}, title = {{{Heuristics and Simulation for Water Tank Optimization}}}, doi = {{10.1007/978-3-319-96271-9_5}}, year = {{2018}}, }