[{"series_title":"GECCO ’21","language":[{"iso":"eng"}],"date_updated":"2023-12-13T10:45:22Z","doi":"10.1145/3449639.3459364","department":[{"_id":"819"}],"publication_status":"published","publication_identifier":{"isbn":["978-1-4503-8350-9"]},"place":"New York, NY, USA","title":"Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms","year":"2021","citation":{"ieee":"J. Bossek, A. Neumann, and F. Neumann, “Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms,” in Proceedings of the Genetic and Evolutionary Computation Conference, 2021, pp. 556–564, doi: 10.1145/3449639.3459364.","short":"J. Bossek, A. Neumann, F. Neumann, in: Proceedings of the Genetic and Evolutionary Computation Conference, Association for Computing Machinery, New York, NY, USA, 2021, pp. 556–564.","mla":"Bossek, Jakob, et al. “Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms.” Proceedings of the Genetic and Evolutionary Computation Conference, Association for Computing Machinery, 2021, pp. 556–564, doi:10.1145/3449639.3459364.","bibtex":"@inproceedings{Bossek_Neumann_Neumann_2021, place={New York, NY, USA}, series={GECCO ’21}, title={Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms}, DOI={10.1145/3449639.3459364}, booktitle={Proceedings of the Genetic and Evolutionary Computation Conference}, publisher={Association for Computing Machinery}, author={Bossek, Jakob and Neumann, Aneta and Neumann, Frank}, year={2021}, pages={556–564}, collection={GECCO ’21} }","chicago":"Bossek, Jakob, Aneta Neumann, and Frank Neumann. “Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms.” In Proceedings of the Genetic and Evolutionary Computation Conference, 556–564. GECCO ’21. New York, NY, USA: Association for Computing Machinery, 2021. https://doi.org/10.1145/3449639.3459364.","apa":"Bossek, J., Neumann, A., & Neumann, F. (2021). Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms. Proceedings of the Genetic and Evolutionary Computation Conference, 556–564. https://doi.org/10.1145/3449639.3459364","ama":"Bossek J, Neumann A, Neumann F. Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms. In: Proceedings of the Genetic and Evolutionary Computation Conference. GECCO ’21. Association for Computing Machinery; 2021:556–564. doi:10.1145/3449639.3459364"},"type":"conference","page":"556–564","_id":"48853","publisher":"Association for Computing Machinery","author":[{"full_name":"Bossek, Jakob","orcid":"0000-0002-4121-4668","first_name":"Jakob","id":"102979","last_name":"Bossek"},{"first_name":"Aneta","full_name":"Neumann, Aneta","last_name":"Neumann"},{"last_name":"Neumann","full_name":"Neumann, Frank","first_name":"Frank"}],"publication":"Proceedings of the Genetic and Evolutionary Computation Conference","keyword":["evolutionary algorithms","evolutionary diversity optimization","knapsack problem","tailored operators"],"status":"public","date_created":"2023-11-14T15:58:54Z","abstract":[{"lang":"eng","text":"In practise, it is often desirable to provide the decision-maker with a rich set of diverse solutions of decent quality instead of just a single solution. In this paper we study evolutionary diversity optimization for the knapsack problem (KP). Our goal is to evolve a population of solutions that all have a profit of at least (1 - {$ϵ$}) {$\\cdot$} OPT, where OPT is the value of an optimal solution. Furthermore, they should differ in structure with respect to an entropy-based diversity measure. To this end we propose a simple ({$\\mu$} + 1)-EA with initial approximate solutions calculated by a well-known FPTAS for the KP. We investigate the effect of different standard mutation operators and introduce biased mutation and crossover which puts strong probability on flipping bits of low and/or high frequency within the population. An experimental study on different instances and settings shows that the proposed mutation operators in most cases perform slightly inferior in the long term, but show strong benefits if the number of function evaluations is severely limited."}],"extern":"1","user_id":"102979"},{"title":"Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem","place":"New York, NY, USA","publication_identifier":{"isbn":["978-1-4503-8350-9"]},"publication_status":"published","department":[{"_id":"819"}],"doi":"10.1145/3449639.3459363","date_updated":"2023-12-13T10:45:37Z","language":[{"iso":"eng"}],"series_title":"GECCO ’21","user_id":"102979","abstract":[{"text":"In the area of evolutionary computation the calculation of diverse sets of high-quality solutions to a given optimization problem has gained momentum in recent years under the term evolutionary diversity optimization. Theoretical insights into the working principles of baseline evolutionary algorithms for diversity optimization are still rare. In this paper we study the well-known Minimum Spanning Tree problem (MST) in the context of diversity optimization where population diversity is measured by the sum of pairwise edge overlaps. Theoretical results provide insights into the fitness landscape of the MST diversity optimization problem pointing out that even for a population of {$\\mu$} = 2 fitness plateaus (of constant length) can be reached, but nevertheless diverse sets can be calculated in polynomial time. We supplement our theoretical results with a series of experiments for the unconstrained and constraint case where all solutions need to fulfill a minimal quality threshold. Our results show that a simple ({$\\mu$} + 1)-EA can effectively compute a diversified population of spanning trees of high quality.","lang":"eng"}],"extern":"1","status":"public","date_created":"2023-11-14T15:58:55Z","author":[{"last_name":"Bossek","id":"102979","first_name":"Jakob","orcid":"0000-0002-4121-4668","full_name":"Bossek, Jakob"},{"last_name":"Neumann","full_name":"Neumann, Frank","first_name":"Frank"}],"publisher":"Association for Computing Machinery","keyword":["evolutionary algorithms","evolutionary diversity optimization","minimum spanning tree","runtime analysis"],"publication":"Proceedings of the Genetic and Evolutionary Computation Conference","_id":"48860","type":"conference","year":"2021","citation":{"short":"J. Bossek, F. Neumann, in: Proceedings of the Genetic and Evolutionary Computation Conference, Association for Computing Machinery, New York, NY, USA, 2021, pp. 198–206.","ieee":"J. Bossek and F. Neumann, “Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem,” in Proceedings of the Genetic and Evolutionary Computation Conference, 2021, pp. 198–206, doi: 10.1145/3449639.3459363.","chicago":"Bossek, Jakob, and Frank Neumann. “Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem.” In Proceedings of the Genetic and Evolutionary Computation Conference, 198–206. GECCO ’21. New York, NY, USA: Association for Computing Machinery, 2021. https://doi.org/10.1145/3449639.3459363.","ama":"Bossek J, Neumann F. Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem. In: Proceedings of the Genetic and Evolutionary Computation Conference. GECCO ’21. Association for Computing Machinery; 2021:198–206. doi:10.1145/3449639.3459363","apa":"Bossek, J., & Neumann, F. (2021). Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem. Proceedings of the Genetic and Evolutionary Computation Conference, 198–206. https://doi.org/10.1145/3449639.3459363","mla":"Bossek, Jakob, and Frank Neumann. “Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem.” Proceedings of the Genetic and Evolutionary Computation Conference, Association for Computing Machinery, 2021, pp. 198–206, doi:10.1145/3449639.3459363.","bibtex":"@inproceedings{Bossek_Neumann_2021, place={New York, NY, USA}, series={GECCO ’21}, title={Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem}, DOI={10.1145/3449639.3459363}, booktitle={Proceedings of the Genetic and Evolutionary Computation Conference}, publisher={Association for Computing Machinery}, author={Bossek, Jakob and Neumann, Frank}, year={2021}, pages={198–206}, collection={GECCO ’21} }"},"page":"198–206"},{"status":"public","date_created":"2023-11-14T15:58:54Z","volume":83,"author":[{"id":"102979","last_name":"Bossek","orcid":"0000-0002-4121-4668","full_name":"Bossek, Jakob","first_name":"Jakob"},{"last_name":"Neumann","first_name":"Frank","full_name":"Neumann, Frank"},{"last_name":"Peng","full_name":"Peng, Pan","first_name":"Pan"},{"last_name":"Sudholt","full_name":"Sudholt, Dirk","first_name":"Dirk"}],"keyword":["Dynamic optimization","Evolutionary algorithms","Running time analysis"],"publication":"Algorithmica","user_id":"102979","abstract":[{"lang":"eng","text":"We contribute to the theoretical understanding of randomized search heuristics for dynamic problems. We consider the classical vertex coloring problem on graphs and investigate the dynamic setting where edges are added to the current graph. We then analyze the expected time for randomized search heuristics to recompute high quality solutions. The (1+1) Evolutionary Algorithm and RLS operate in a setting where the number of colors is bounded and we are minimizing the number of conflicts. Iterated local search algorithms use an unbounded color palette and aim to use the smallest colors and, consequently, the smallest number of colors. We identify classes of bipartite graphs where reoptimization is as hard as or even harder than optimization from scratch, i.e., starting with a random initialization. Even adding a single edge can lead to hard symmetry problems. However, graph classes that are hard for one algorithm turn out to be easy for others. In most cases our bounds show that reoptimization is faster than optimizing from scratch. We further show that tailoring mutation operators to parts of the graph where changes have occurred can significantly reduce the expected reoptimization time. In most settings the expected reoptimization time for such tailored algorithms is linear in the number of added edges. However, tailored algorithms cannot prevent exponential times in settings where the original algorithm is inefficient."}],"type":"journal_article","citation":{"mla":"Bossek, Jakob, et al. “Time Complexity Analysis of Randomized Search Heuristics for the Dynamic Graph Coloring Problem.” Algorithmica, vol. 83, no. 10, 2021, pp. 3148–3179, doi:10.1007/s00453-021-00838-3.","bibtex":"@article{Bossek_Neumann_Peng_Sudholt_2021, title={Time Complexity Analysis of Randomized Search Heuristics for the Dynamic Graph Coloring Problem}, volume={83}, DOI={10.1007/s00453-021-00838-3}, number={10}, journal={Algorithmica}, author={Bossek, Jakob and Neumann, Frank and Peng, Pan and Sudholt, Dirk}, year={2021}, pages={3148–3179} }","apa":"Bossek, J., Neumann, F., Peng, P., & Sudholt, D. (2021). Time Complexity Analysis of Randomized Search Heuristics for the Dynamic Graph Coloring Problem. Algorithmica, 83(10), 3148–3179. https://doi.org/10.1007/s00453-021-00838-3","ama":"Bossek J, Neumann F, Peng P, Sudholt D. Time Complexity Analysis of Randomized Search Heuristics for the Dynamic Graph Coloring Problem. Algorithmica. 2021;83(10):3148–3179. doi:10.1007/s00453-021-00838-3","chicago":"Bossek, Jakob, Frank Neumann, Pan Peng, and Dirk Sudholt. “Time Complexity Analysis of Randomized Search Heuristics for the Dynamic Graph Coloring Problem.” Algorithmica 83, no. 10 (2021): 3148–3179. https://doi.org/10.1007/s00453-021-00838-3.","ieee":"J. Bossek, F. Neumann, P. Peng, and D. Sudholt, “Time Complexity Analysis of Randomized Search Heuristics for the Dynamic Graph Coloring Problem,” Algorithmica, vol. 83, no. 10, pp. 3148–3179, 2021, doi: 10.1007/s00453-021-00838-3.","short":"J. Bossek, F. Neumann, P. Peng, D. Sudholt, Algorithmica 83 (2021) 3148–3179."},"year":"2021","page":"3148–3179","issue":"10","intvolume":" 83","_id":"48854","publication_identifier":{"issn":["0178-4617"]},"department":[{"_id":"819"}],"title":"Time Complexity Analysis of Randomized Search Heuristics for the Dynamic Graph Coloring Problem","language":[{"iso":"eng"}],"doi":"10.1007/s00453-021-00838-3","date_updated":"2023-12-13T10:51:34Z"},{"user_id":"35343","ddc":["006"],"abstract":[{"text":"Modern services comprise interconnected components,\r\ne.g., microservices in a service mesh, that can scale and\r\nrun on multiple nodes across the network on demand. To process\r\nincoming traffic, service components have to be instantiated and\r\ntraffic assigned to these instances, taking capacities and changing\r\ndemands into account. This challenge is usually solved with\r\ncustom approaches designed by experts. While this typically\r\nworks well for the considered scenario, the models often rely\r\non unrealistic assumptions or on knowledge that is not available\r\nin practice (e.g., a priori knowledge).\r\n\r\nWe propose a novel deep reinforcement learning approach that\r\nlearns how to best coordinate services and is geared towards\r\nrealistic assumptions. It interacts with the network and relies on\r\navailable, possibly delayed monitoring information. Rather than\r\ndefining a complex model or an algorithm how to achieve an\r\nobjective, our model-free approach adapts to various objectives\r\nand traffic patterns. An agent is trained offline without expert\r\nknowledge and then applied online with minimal overhead. Compared\r\nto a state-of-the-art heuristic, it significantly improves flow\r\nthroughput and overall network utility on real-world network\r\ntopologies and traffic traces. It also learns to optimize different\r\nobjectives, generalizes to scenarios with unseen, stochastic traffic\r\npatterns, and scales to large real-world networks.","lang":"eng"}],"date_created":"2020-09-22T06:28:22Z","has_accepted_license":"1","status":"public","file":[{"file_id":"19610","creator":"stschn","file_size":642999,"relation":"main_file","date_updated":"2020-09-22T06:36:00Z","content_type":"application/pdf","file_name":"ris_with_copyright.pdf","date_created":"2020-09-22T06:29:16Z","access_level":"open_access"}],"keyword":["self-driving networks","self-learning","network coordination","service coordination","reinforcement learning","deep learning","nfv"],"publication":"IEEE International Conference on Network and Service Management (CNSM)","file_date_updated":"2020-09-22T06:36:00Z","author":[{"orcid":"0000-0001-8210-4011","full_name":"Schneider, Stefan Balthasar","first_name":"Stefan Balthasar","id":"35343","last_name":"Schneider"},{"last_name":"Manzoor","first_name":"Adnan","full_name":"Manzoor, Adnan"},{"full_name":"Qarawlus, Haydar","first_name":"Haydar","last_name":"Qarawlus"},{"full_name":"Schellenberg, Rafael","first_name":"Rafael","last_name":"Schellenberg"},{"last_name":"Karl","id":"126","first_name":"Holger","full_name":"Karl, Holger"},{"last_name":"Khalili","first_name":"Ramin","full_name":"Khalili, Ramin"},{"first_name":"Artur","full_name":"Hecker, Artur","last_name":"Hecker"}],"publisher":"IEEE","_id":"19609","citation":{"ieee":"S. B. Schneider et al., “Self-Driving Network and Service Coordination Using Deep Reinforcement Learning,” in IEEE International Conference on Network and Service Management (CNSM), 2020.","short":"S.B. Schneider, A. Manzoor, H. Qarawlus, R. Schellenberg, H. Karl, R. Khalili, A. Hecker, in: IEEE International Conference on Network and Service Management (CNSM), IEEE, 2020.","mla":"Schneider, Stefan Balthasar, et al. “Self-Driving Network and Service Coordination Using Deep Reinforcement Learning.” IEEE International Conference on Network and Service Management (CNSM), IEEE, 2020.","bibtex":"@inproceedings{Schneider_Manzoor_Qarawlus_Schellenberg_Karl_Khalili_Hecker_2020, title={Self-Driving Network and Service Coordination Using Deep Reinforcement Learning}, booktitle={IEEE International Conference on Network and Service Management (CNSM)}, publisher={IEEE}, author={Schneider, Stefan Balthasar and Manzoor, Adnan and Qarawlus, Haydar and Schellenberg, Rafael and Karl, Holger and Khalili, Ramin and Hecker, Artur}, year={2020} }","chicago":"Schneider, Stefan Balthasar, Adnan Manzoor, Haydar Qarawlus, Rafael Schellenberg, Holger Karl, Ramin Khalili, and Artur Hecker. “Self-Driving Network and Service Coordination Using Deep Reinforcement Learning.” In IEEE International Conference on Network and Service Management (CNSM). IEEE, 2020.","ama":"Schneider SB, Manzoor A, Qarawlus H, et al. Self-Driving Network and Service Coordination Using Deep Reinforcement Learning. In: IEEE International Conference on Network and Service Management (CNSM). IEEE; 2020.","apa":"Schneider, S. B., Manzoor, A., Qarawlus, H., Schellenberg, R., Karl, H., Khalili, R., & Hecker, A. (2020). Self-Driving Network and Service Coordination Using Deep Reinforcement Learning. In IEEE International Conference on Network and Service Management (CNSM). IEEE."},"type":"conference","year":"2020","title":"Self-Driving Network and Service Coordination Using Deep Reinforcement Learning","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Project Area C","_id":"4"},{"_id":"16","name":"SFB 901 - Subproject C4"}],"department":[{"_id":"75"}],"oa":"1","date_updated":"2022-01-06T06:54:08Z","language":[{"iso":"eng"}]},{"title":"Process design for the forming of semi-tubular self-piercing rivets made of high nitrogen steel","editor":[{"last_name":"Kuball","full_name":"Kuball, Clara-Maria","first_name":"Clara-Maria"},{"last_name":"Uhe","id":"38131","first_name":"Benedikt","full_name":"Uhe, Benedikt"},{"orcid":"0000-0002-2763-1246","full_name":"Meschut, Gerson","first_name":"Gerson","id":"32056","last_name":"Meschut"},{"full_name":"Merklein, Marion","first_name":"Marion","last_name":"Merklein"}],"publication_status":"published","department":[{"_id":"157"}],"doi":"10.1016/j.promfg.2020.08.052","date_updated":"2022-01-06T06:54:17Z","language":[{"iso":"eng"}],"series_title":"Procedia Manufacturing","user_id":"38131","abstract":[{"lang":"eng","text":"The aim to reduce pollutant emission has led to a trend towards lightweight construction in car body development during the last years. As a consequence of the resulting need for multi-material design, mechanical joining technologies become increasingly important. Mechanical joining allows for the combination of dissimilar materials, while thermic joining techniques reach their limits. Self-piercing riveting enables the joining of dissimilar materials by using semi-tubular rivets as mechanical fasteners. The rivet production, however, is costly and time-consuming, as the rivets generally have to be hardened, tempered and coated after forming, in order to achieve an adequate strength and corrosion resistance. A promising approach to improve the efficiency of the rivet manufacturing is the use of high-strength high nitrogen steel as rivet material because these additional process steps would not be necessary anymore. As a result of the comparatively high nitrogen content, such steels have various beneficial properties like higher strength, good ductility and improved corrosion resistance. By cold bulk forming of high nitrogen steels high-strength parts can be manufactured due to the strengthening which is caused by the high strain hardening. However, high tool loads thereby have to be expected and are a major challenge during the production process. Consequently, there is a need for appropriate forming strategies. This paper presents key aspects concerning the process design for the manufacturing of semi-tubular self-piercing rivets made of high-strength steel. The aim is to produce the rivets in several forming stages without intermediate heat treatment between the single stages. Due to the high strain hardening of the material, a two stage forming concept will be investigated. Cup-backward extrusion is chosen as the first process step in order to form the rivet shank without forming the rivet foot. Thus, the strain hardening effects in the area of the rivet foot are minimized and the tool loads during the following process step can be reduced. During the second and final forming stage the detailed geometry of the rivet foot and the rivet head is formed. In this context, the effect of different variations, for example concerning the final geometry of the rivet foot, on the tool load is investigated using multistage numerical analysis. Furthermore, the influence of the process temperature on occurring stresses is analysed. Based on the results of the investigations, an adequate forming strategy and a tool concept for the manufacturing of semi-tubular self-piercing rivets made of high-strength steel are presented."}],"volume":50,"status":"public","date_created":"2020-10-12T08:30:08Z","quality_controlled":"1","keyword":["high nitrogen steel","self-piercing riveting","joining by forming","bulk forming","tool design"],"intvolume":" 50","_id":"19976","type":"conference_editor","year":"2020","citation":{"chicago":"Kuball, Clara-Maria, Benedikt Uhe, Gerson Meschut, and Marion Merklein, eds. Process Design for the Forming of Semi-Tubular Self-Piercing Rivets Made of High Nitrogen Steel. Vol. 50. Procedia Manufacturing, 2020. https://doi.org/10.1016/j.promfg.2020.08.052.","apa":"Kuball, C.-M., Uhe, B., Meschut, G., & Merklein, M. (Eds.). (2020). Process design for the forming of semi-tubular self-piercing rivets made of high nitrogen steel (Vol. 50, pp. 280–285). https://doi.org/10.1016/j.promfg.2020.08.052","ama":"Kuball C-M, Uhe B, Meschut G, Merklein M, eds. Process Design for the Forming of Semi-Tubular Self-Piercing Rivets Made of High Nitrogen Steel. Vol 50.; 2020:280-285. doi:10.1016/j.promfg.2020.08.052","mla":"Kuball, Clara-Maria, et al., editors. Process Design for the Forming of Semi-Tubular Self-Piercing Rivets Made of High Nitrogen Steel. Vol. 50, 2020, pp. 280–85, doi:10.1016/j.promfg.2020.08.052.","bibtex":"@book{Kuball_Uhe_Meschut_Merklein_2020, series={Procedia Manufacturing}, title={Process design for the forming of semi-tubular self-piercing rivets made of high nitrogen steel}, volume={50}, DOI={10.1016/j.promfg.2020.08.052}, year={2020}, pages={280–285}, collection={Procedia Manufacturing} }","short":"C.-M. Kuball, B. Uhe, G. Meschut, M. Merklein, eds., Process Design for the Forming of Semi-Tubular Self-Piercing Rivets Made of High Nitrogen Steel, 2020.","ieee":"C.-M. Kuball, B. Uhe, G. Meschut, and M. Merklein, Eds., Process design for the forming of semi-tubular self-piercing rivets made of high nitrogen steel, vol. 50. 2020, pp. 280–285."},"page":"280-285"},{"ddc":["000"],"user_id":"39241","abstract":[{"text":" We consider a natural extension to the metric uncapacitated Facility Location Problem (FLP) in which requests ask for different commodities out of a finite set \\( S \\) of commodities.\r\n Ravi and Sinha (SODA 2004) introduced the model as the \\emph{Multi-Commodity Facility Location Problem} (MFLP) and considered it an offline optimization problem.\r\n The model itself is similar to the FLP: i.e., requests are located at points of a finite metric space and the task of an algorithm is to construct facilities and assign requests to facilities while minimizing the construction cost and the sum over all assignment distances.\r\n In addition, requests and facilities are heterogeneous; they request or offer multiple commodities out of $S$.\r\n A request has to be connected to a set of facilities jointly offering the commodities demanded by it.\r\n In comparison to the FLP, an algorithm has to decide not only if and where to place facilities, but also which commodities to offer at each.\r\n\r\n To the best of our knowledge we are the first to study the problem in its online variant in which requests, their positions and their commodities are not known beforehand but revealed over time.\r\n We present results regarding the competitive ratio.\r\n On the one hand, we show that heterogeneity influences the competitive ratio by developing a lower bound on the competitive ratio for any randomized online algorithm of \\( \\Omega ( \\sqrt{|S|} + \\frac{\\log n}{\\log \\log n} ) \\) that already holds for simple line metrics.\r\n Here, \\( n \\) is the number of requests.\r\n On the other side, we establish a deterministic \\( \\mathcal{O}(\\sqrt{|S|} \\cdot \\log n) \\)-competitive algorithm and a randomized \\( \\mathcal{O}(\\sqrt{|S|} \\cdot \\frac{\\log n}{\\log \\log n} ) \\)-competitive algorithm.\r\n Further, we show that when considering a more special class of cost functions for the construction cost of a facility, the competitive ratio decreases given by our deterministic algorithm depending on the function.","lang":"eng"}],"has_accepted_license":"1","status":"public","date_created":"2020-07-14T07:53:20Z","author":[{"last_name":"Castenow","id":"38705","first_name":"Jannik","full_name":"Castenow, Jannik"},{"id":"22704","last_name":"Feldkord","full_name":"Feldkord, Björn","first_name":"Björn"},{"last_name":"Knollmann","id":"39241","first_name":"Till","full_name":"Knollmann, Till","orcid":"0000-0003-2014-4696"},{"last_name":"Malatyali","first_name":"Manuel","full_name":"Malatyali, Manuel"},{"id":"15523","last_name":"Meyer auf der Heide","full_name":"Meyer auf der Heide, Friedhelm","first_name":"Friedhelm"}],"file_date_updated":"2020-07-14T07:56:52Z","publication":"Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures","keyword":["Online Multi-Commodity Facility Location","Competitive Ratio","Online Optimization","Facility Location Problem"],"file":[{"file_name":"3350755.3400281.pdf","date_created":"2020-07-14T07:56:52Z","access_level":"closed","file_size":1271416,"creator":"tillk","file_id":"17373","content_type":"application/pdf","date_updated":"2020-07-14T07:56:52Z","relation":"main_file","success":1}],"_id":"17370","year":"2020","citation":{"ieee":"J. Castenow, B. Feldkord, T. Knollmann, M. Malatyali, and F. Meyer auf der Heide, “The Online Multi-Commodity Facility Location Problem,” in Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures, 2020.","short":"J. Castenow, B. Feldkord, T. Knollmann, M. Malatyali, F. Meyer auf der Heide, in: Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures, 2020.","mla":"Castenow, Jannik, et al. “The Online Multi-Commodity Facility Location Problem.” Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures, 2020, doi:10.1145/3350755.3400281.","bibtex":"@inproceedings{Castenow_Feldkord_Knollmann_Malatyali_Meyer auf der Heide_2020, title={The Online Multi-Commodity Facility Location Problem}, DOI={10.1145/3350755.3400281}, booktitle={Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures}, author={Castenow, Jannik and Feldkord, Björn and Knollmann, Till and Malatyali, Manuel and Meyer auf der Heide, Friedhelm}, year={2020} }","chicago":"Castenow, Jannik, Björn Feldkord, Till Knollmann, Manuel Malatyali, and Friedhelm Meyer auf der Heide. “The Online Multi-Commodity Facility Location Problem.” In Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures, 2020. https://doi.org/10.1145/3350755.3400281.","apa":"Castenow, J., Feldkord, B., Knollmann, T., Malatyali, M., & Meyer auf der Heide, F. (2020). The Online Multi-Commodity Facility Location Problem. In Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures. https://doi.org/10.1145/3350755.3400281","ama":"Castenow J, Feldkord B, Knollmann T, Malatyali M, Meyer auf der Heide F. The Online Multi-Commodity Facility Location Problem. In: Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures. ; 2020. doi:10.1145/3350755.3400281"},"type":"conference","title":"The Online Multi-Commodity Facility Location Problem","external_id":{"arxiv":["2005.08391"]},"publication_identifier":{"isbn":["9781450369350"]},"publication_status":"published","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Project Area A","_id":"2"},{"_id":"5","name":"SFB 901 - Subproject A1"}],"department":[{"_id":"63"}],"doi":"10.1145/3350755.3400281","date_updated":"2022-01-06T06:53:10Z","language":[{"iso":"eng"}]},{"main_file_link":[{"open_access":"1"}],"type":"journal_article","citation":{"bibtex":"@article{Otroshi_Rossel_Meschut_2020, title={Stress state dependent damage modeling of self-pierce riveting process simulation using GISSMO damage model}, volume={1}, DOI={10.1016/j.jajp.2020.100015}, journal={Journal of Advanced Joining Processes}, publisher={Elsevier}, author={Otroshi, Mortaza and Rossel, Moritz and Meschut, Gerson}, year={2020} }","mla":"Otroshi, Mortaza, et al. “Stress State Dependent Damage Modeling of Self-Pierce Riveting Process Simulation Using GISSMO Damage Model.” Journal of Advanced Joining Processes, vol. 1, Elsevier, 2020, doi:10.1016/j.jajp.2020.100015.","chicago":"Otroshi, Mortaza, Moritz Rossel, and Gerson Meschut. “Stress State Dependent Damage Modeling of Self-Pierce Riveting Process Simulation Using GISSMO Damage Model.” Journal of Advanced Joining Processes 1 (2020). https://doi.org/10.1016/j.jajp.2020.100015.","apa":"Otroshi, M., Rossel, M., & Meschut, G. (2020). Stress state dependent damage modeling of self-pierce riveting process simulation using GISSMO damage model. Journal of Advanced Joining Processes, 1. https://doi.org/10.1016/j.jajp.2020.100015","ama":"Otroshi M, Rossel M, Meschut G. Stress state dependent damage modeling of self-pierce riveting process simulation using GISSMO damage model. Journal of Advanced Joining Processes. 2020;1. doi:10.1016/j.jajp.2020.100015","ieee":"M. Otroshi, M. Rossel, and G. Meschut, “Stress state dependent damage modeling of self-pierce riveting process simulation using GISSMO damage model,” Journal of Advanced Joining Processes, vol. 1, 2020, doi: 10.1016/j.jajp.2020.100015.","short":"M. Otroshi, M. Rossel, G. Meschut, Journal of Advanced Joining Processes 1 (2020)."},"year":"2020","intvolume":" 1","_id":"20143","author":[{"first_name":"Mortaza","orcid":"0000-0002-8652-9209","full_name":"Otroshi, Mortaza","last_name":"Otroshi","id":"71269"},{"last_name":"Rossel","first_name":"Moritz","full_name":"Rossel, Moritz"},{"last_name":"Meschut","id":"32056","first_name":"Gerson","orcid":"0000-0002-2763-1246","full_name":"Meschut, Gerson"}],"quality_controlled":"1","publisher":"Elsevier","publication":"Journal of Advanced Joining Processes","keyword":["Self-pierce riveting","Ductile fracture","Damage modeling","GISSMO damage model"],"status":"public","date_created":"2020-10-20T14:49:15Z","volume":1,"user_id":"71269","language":[{"iso":"eng"}],"date_updated":"2022-04-25T07:49:50Z","oa":"1","doi":"10.1016/j.jajp.2020.100015","department":[{"_id":"157"}],"title":"Stress state dependent damage modeling of self-pierce riveting process simulation using GISSMO damage model"},{"year":"2020","citation":{"bibtex":"@article{Caruso_Adammek_Bonanati_Wiescholek_2020, title={Motivierende Lernzugänge als Ausgangspunkt der Professionalisierung angehender Lehrer_innen}, volume={3}, DOI={10.4119/hlz-2540}, number={1}, journal={Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion}, author={Caruso, Carina and Adammek, Christine and Bonanati, Sabrina and Wiescholek, Sybille}, year={2020}, pages={18–33} }","mla":"Caruso, Carina, et al. “Motivierende Lernzugänge als Ausgangspunkt der Professionalisierung angehender Lehrer_innen.” Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion, vol. 3, no. 1, 2020, pp. 18–33, doi:10.4119/hlz-2540.","ama":"Caruso C, Adammek C, Bonanati S, Wiescholek S. Motivierende Lernzugänge als Ausgangspunkt der Professionalisierung angehender Lehrer_innen. Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion. 2020;3(1):18-33. doi:10.4119/hlz-2540","apa":"Caruso, C., Adammek, C., Bonanati, S., & Wiescholek, S. (2020). Motivierende Lernzugänge als Ausgangspunkt der Professionalisierung angehender Lehrer_innen. Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion, 3(1), 18–33. https://doi.org/10.4119/hlz-2540","chicago":"Caruso, Carina, Christine Adammek, Sabrina Bonanati, and Sybille Wiescholek. “Motivierende Lernzugänge als Ausgangspunkt der Professionalisierung angehender Lehrer_innen.” Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion 3, no. 1 (2020): 18–33. https://doi.org/10.4119/hlz-2540.","ieee":"C. Caruso, C. Adammek, S. Bonanati, and S. Wiescholek, “Motivierende Lernzugänge als Ausgangspunkt der Professionalisierung angehender Lehrer_innen,” Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion, vol. 3, no. 1, pp. 18–33, 2020, doi: 10.4119/hlz-2540.","short":"C. Caruso, C. Adammek, S. Bonanati, S. Wiescholek, Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion 3 (2020) 18–33."},"type":"journal_article","page":"18-33","intvolume":" 3","_id":"35298","issue":"1","author":[{"first_name":"Carina","full_name":"Caruso, Carina","last_name":"Caruso","id":"23123"},{"last_name":"Adammek","full_name":"Adammek, Christine","first_name":"Christine"},{"last_name":"Bonanati","full_name":"Bonanati, Sabrina","first_name":"Sabrina"},{"full_name":"Wiescholek, Sybille","first_name":"Sybille","last_name":"Wiescholek"}],"keyword":["ästhetische Forschung","Biographiearbeit","Praxissemester","Professionalisierung","selbstreguliertes Lernen","Motivation / aesthetic research","biographical work","long-term internship","profes-sionalization","self-regulated learning","motivation"],"publication":"Herausforderung Lehrer*innenbildung - Zeitschrift Zur Konzeption, Gestaltung Und Diskussion","status":"public","date_created":"2023-01-05T13:58:28Z","alternative_title":["Ein Blick auf kompetenzorientiertes, ästhetisches und biographisches Lernen im Lehramtsstudium"],"volume":3,"abstract":[{"text":"Im Artikel werden drei verschiedene Lernzugänge (kom-petenzorientiertes, ästhetisches und biographisches Lernen) vorgestellt und aus theoretischer Perspektive deren motivierender Gehalt für selbstreguliertes Lernen in Praxisphasen des Lehramtsstudiumsherausgearbeitet. Als theoretische Grund-lage dient die Selbstbestimmungstheorie als zentrale motivationale Theorie zur Erklärung selbstbestimmten Handelns.","lang":"ger"},{"lang":"eng","text":"The article addresses how motivational learning approaches (competency-oriented, aesthetic and biographical) can contribute to the professionalization of preservice teachers during a long-term internship. As a theoretical basis, the self-determination theory serves as a central motivational theory for explaining self-determined action."}],"user_id":"86519","language":[{"iso":"other"}],"date_updated":"2023-01-06T12:18:16Z","doi":"10.4119/hlz-2540","publication_identifier":{"issn":["2625-0675"]},"publication_status":"published","title":"Motivierende Lernzugänge als Ausgangspunkt der Professionalisierung angehender Lehrer_innen"},{"intvolume":" 27","_id":"33866","article_number":"S10","type":"journal_article","citation":{"ama":"Bonnard B, Cots O, Wembe Moafo BE. A Zermelo navigation problem with a vortex singularity. ESAIM: Control, Optimisation and Calculus of Variations. 2020;27. doi:10.1051/cocv/2020058","apa":"Bonnard, B., Cots, O., & Wembe Moafo, B. E. (2020). A Zermelo navigation problem with a vortex singularity. ESAIM: Control, Optimisation and Calculus of Variations, 27, Article S10. https://doi.org/10.1051/cocv/2020058","chicago":"Bonnard, Bernard, Olivier Cots, and Boris Edgar Wembe Moafo. “A Zermelo Navigation Problem with a Vortex Singularity.” ESAIM: Control, Optimisation and Calculus of Variations 27 (2020). https://doi.org/10.1051/cocv/2020058.","mla":"Bonnard, Bernard, et al. “A Zermelo Navigation Problem with a Vortex Singularity.” ESAIM: Control, Optimisation and Calculus of Variations, vol. 27, S10, EDP Sciences, 2020, doi:10.1051/cocv/2020058.","bibtex":"@article{Bonnard_Cots_Wembe Moafo_2020, title={A Zermelo navigation problem with a vortex singularity}, volume={27}, DOI={10.1051/cocv/2020058}, number={S10}, journal={ESAIM: Control, Optimisation and Calculus of Variations}, publisher={EDP Sciences}, author={Bonnard, Bernard and Cots, Olivier and Wembe Moafo, Boris Edgar}, year={2020} }","short":"B. Bonnard, O. Cots, B.E. Wembe Moafo, ESAIM: Control, Optimisation and Calculus of Variations 27 (2020).","ieee":"B. Bonnard, O. Cots, and B. E. Wembe Moafo, “A Zermelo navigation problem with a vortex singularity,” ESAIM: Control, Optimisation and Calculus of Variations, vol. 27, Art. no. S10, 2020, doi: 10.1051/cocv/2020058."},"year":"2020","abstract":[{"text":"Helhmoltz–Kirchhoff equations of motions of vortices of an incompressible fluid in the plane define a dynamics with singularities and this leads to a Zermelo navigation problem describing the ship travel in such a field where the control is the heading angle. Considering one vortex, we define a time minimization problem which can be analyzed with the technics of geometric optimal control combined with numerical simulations, the geometric frame being the extension of Randers metrics in the punctured plane, with rotational symmetry. Candidates as minimizers are parameterized thanks to the Pontryagin Maximum Principle as extremal solutions of a Hamiltonian vector field. We analyze the time minimal solution to transfer the ship between two points where during the transfer the ship can be either in a strong current region in the vicinity of the vortex or in a weak current region. The analysis is based on a micro-local classification of the extremals using mainly the integrability properties of the dynamics due to the rotational symmetry. The discussion is complex and related to the existence of an isolated extremal (Reeb) circle due to the vortex singularity. The explicit computation of cut points where the extremal curves cease to be optimal is given and the spheres are described in the case where at the initial point the current is weak.","lang":"eng"}],"user_id":"95394","keyword":["Computational Mathematics","Control and Optimization","Control and Systems Engineering"],"publication":"ESAIM: Control, Optimisation and Calculus of Variations","author":[{"first_name":"Bernard","full_name":"Bonnard, Bernard","last_name":"Bonnard"},{"last_name":"Cots","full_name":"Cots, Olivier","first_name":"Olivier"},{"first_name":"Boris Edgar","full_name":"Wembe Moafo, Boris Edgar","last_name":"Wembe Moafo","id":"95394"}],"publisher":"EDP Sciences","date_created":"2022-10-24T12:51:05Z","status":"public","volume":27,"date_updated":"2023-01-16T12:09:22Z","doi":"10.1051/cocv/2020058","language":[{"iso":"eng"}],"title":"A Zermelo navigation problem with a vortex singularity","publication_identifier":{"issn":["1292-8119","1262-3377"]},"publication_status":"published"},{"language":[{"iso":"eng"}],"series_title":"Journal of Advanced Joining Processes","doi":"10.1016/j.jajp.2020.100023","date_updated":"2023-04-28T09:19:41Z","publication_status":"published","editor":[{"last_name":"Kuball","first_name":"Clara-Maria","full_name":"Kuball, Clara-Maria"},{"last_name":"Jung","first_name":"R","full_name":"Jung, R"},{"last_name":"Uhe","id":"38131","first_name":"Benedikt","full_name":"Uhe, Benedikt"},{"first_name":"Gerson","full_name":"Meschut, Gerson","orcid":"0000-0002-2763-1246","last_name":"Meschut","id":"32056"},{"full_name":"Merklein, Marion","first_name":"Marion","last_name":"Merklein"}],"department":[{"_id":"157"}],"title":"Influence of the process temperature on the forming behaviour and the friction during bulk forming of high nitrogen steel","type":"conference_editor","year":"2020","citation":{"mla":"Kuball, Clara-Maria, et al., editors. Influence of the Process Temperature on the Forming Behaviour and the Friction during Bulk Forming of High Nitrogen Steel. 100023, 2020, doi:10.1016/j.jajp.2020.100023.","bibtex":"@book{Kuball_Jung_Uhe_Meschut_Merklein_2020, series={Journal of Advanced Joining Processes}, title={Influence of the process temperature on the forming behaviour and the friction during bulk forming of high nitrogen steel}, volume={1}, DOI={10.1016/j.jajp.2020.100023}, number={100023}, year={2020}, collection={Journal of Advanced Joining Processes} }","ama":"Kuball C-M, Jung R, Uhe B, Meschut G, Merklein M, eds. Influence of the Process Temperature on the Forming Behaviour and the Friction during Bulk Forming of High Nitrogen Steel. Vol 1.; 2020. doi:10.1016/j.jajp.2020.100023","apa":"Kuball, C.-M., Jung, R., Uhe, B., Meschut, G., & Merklein, M. (Eds.). (2020). Influence of the process temperature on the forming behaviour and the friction during bulk forming of high nitrogen steel (No. 100023; Vol. 1). https://doi.org/10.1016/j.jajp.2020.100023","chicago":"Kuball, Clara-Maria, R Jung, Benedikt Uhe, Gerson Meschut, and Marion Merklein, eds. Influence of the Process Temperature on the Forming Behaviour and the Friction during Bulk Forming of High Nitrogen Steel. Vol. 1. Journal of Advanced Joining Processes, 2020. https://doi.org/10.1016/j.jajp.2020.100023.","ieee":"C.-M. Kuball, R. Jung, B. Uhe, G. Meschut, and M. Merklein, Eds., Influence of the process temperature on the forming behaviour and the friction during bulk forming of high nitrogen steel, vol. 1. 2020.","short":"C.-M. Kuball, R. Jung, B. Uhe, G. Meschut, M. Merklein, eds., Influence of the Process Temperature on the Forming Behaviour and the Friction during Bulk Forming of High Nitrogen Steel, 2020."},"article_number":"100023","intvolume":" 1","_id":"19974","volume":1,"date_created":"2020-10-12T08:23:27Z","status":"public","keyword":["High nitrogen steel","Self-piercing riveting","Joining by forming","Bulk forming","Strain hardening"],"quality_controlled":"1","user_id":"38131","abstract":[{"text":"Due to the trend towards lightweight design in car body development mechanical joining technologies become increasingly important. These techniques allow for the joining of dissimilar materials and thus enable multi-material design, while thermic joining methods reach their limits. Semi-tubular self-piercing riveting is an important mechanical joining technology. The rivet production, however, is costly and time-consuming, as the process consists of several process steps including the heat treatment and coating of the rivets in order to achieve an adequate strength and corrosion resistance. The use of high nitrogen steel as rivet material leads to the possibility of reducing process steps and hence increasing the efficiency of the process. However, the high tool loads being expected due to the high strain hardening of the material are a major challenge during the rivet production. Thus, there is a need for appropriate forming strategies, such as the manufacturing of the rivets at elevated temperatures. Prior investigations led to the conclusion that forming already at 200 °C results in a distinct reduction of the yield strength. To create a deeper understanding of the forming behaviour of high nitrogen steel at elevated temperatures, compression tests were conducted in a temperature range between room temperature and 200 °C. The determined true stress – true strain curves are the basis for the further process and tool design of the rivet production. Another key factor for the rivet manufacturing at elevated temperatures is the influence of the process temperature on the tribological conditions. For this reason, ring compression tests at room temperature and 200 °C are carried out. The friction factors are determined on the basis of calibration curves resulting from the numerical analysis of the ring compression process. The investigations indicate that the friction factor at 200 °C is significantly higher compared to room temperature. This essential fact has to be taken into account for the process and tool design for the rivet production using high nitrogen steel.","lang":"eng"}]}]