[{"article_type":"original","user_id":"77201","title":"Research and Consulting in Data-Driven Strategic Product Planning","author":[{"last_name":"Meyer","id":"77201","first_name":"Maurice","full_name":"Meyer, Maurice","orcid":"0000-0003-0606-7321"},{"last_name":"Frank","first_name":"Maximilian","full_name":"Frank, Maximilian"},{"full_name":"Massmann, Melina","first_name":"Melina","last_name":"Massmann"},{"first_name":"Roman","full_name":"Dumitrescu, Roman","last_name":"Dumitrescu","id":"16190"}],"department":[{"_id":"563"}],"publication":"Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020)","status":"public","date_created":"2020-10-02T16:19:50Z","_id":"19864","date_updated":"2022-01-06T06:54:14Z","language":[{"iso":"eng"}],"year":"2020","type":"journal_article","citation":{"ieee":"M. Meyer, M. Frank, M. Massmann, and R. Dumitrescu, “Research and Consulting in Data-Driven Strategic Product Planning,” Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020), 2020.","short":"M. Meyer, M. Frank, M. Massmann, R. Dumitrescu, Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020) (2020).","bibtex":"@article{Meyer_Frank_Massmann_Dumitrescu_2020, title={Research and Consulting in Data-Driven Strategic Product Planning}, journal={Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020)}, author={Meyer, Maurice and Frank, Maximilian and Massmann, Melina and Dumitrescu, Roman}, year={2020} }","mla":"Meyer, Maurice, et al. “Research and Consulting in Data-Driven Strategic Product Planning.” Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020), 2020.","chicago":"Meyer, Maurice, Maximilian Frank, Melina Massmann, and Roman Dumitrescu. “Research and Consulting in Data-Driven Strategic Product Planning.” Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020), 2020.","apa":"Meyer, M., Frank, M., Massmann, M., & Dumitrescu, R. (2020). Research and Consulting in Data-Driven Strategic Product Planning. Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020).","ama":"Meyer M, Frank M, Massmann M, Dumitrescu R. Research and Consulting in Data-Driven Strategic Product Planning. Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020). 2020."}},{"department":[{"_id":"563"}],"publication":"Journal of Systemics, Cybernetics and Informatics","author":[{"full_name":"Meyer, Maurice","orcid":"0000-0003-0606-7321","first_name":"Maurice","id":"77201","last_name":"Meyer"},{"first_name":"Maximilian","full_name":"Frank, Maximilian","last_name":"Frank"},{"last_name":"Massmann","full_name":"Massmann, Melina","first_name":"Melina"},{"id":"16190","last_name":"Dumitrescu","full_name":"Dumitrescu, Roman","first_name":"Roman"}],"volume":18,"date_created":"2020-10-02T16:21:47Z","status":"public","article_type":"original","title":"Research and Consulting in Data-Driven Strategic Product Planning","user_id":"77201","page":"55-61","year":"2020","type":"journal_article","citation":{"ieee":"M. Meyer, M. Frank, M. Massmann, and R. Dumitrescu, “Research and Consulting in Data-Driven Strategic Product Planning,” Journal of Systemics, Cybernetics and Informatics, vol. 18, no. 2, pp. 55–61, 2020.","short":"M. Meyer, M. Frank, M. Massmann, R. Dumitrescu, Journal of Systemics, Cybernetics and Informatics 18 (2020) 55–61.","mla":"Meyer, Maurice, et al. “Research and Consulting in Data-Driven Strategic Product Planning.” Journal of Systemics, Cybernetics and Informatics, vol. 18, no. 2, 2020, pp. 55–61.","bibtex":"@article{Meyer_Frank_Massmann_Dumitrescu_2020, title={Research and Consulting in Data-Driven Strategic Product Planning}, volume={18}, number={2}, journal={Journal of Systemics, Cybernetics and Informatics}, author={Meyer, Maurice and Frank, Maximilian and Massmann, Melina and Dumitrescu, Roman}, year={2020}, pages={55–61} }","chicago":"Meyer, Maurice, Maximilian Frank, Melina Massmann, and Roman Dumitrescu. “Research and Consulting in Data-Driven Strategic Product Planning.” Journal of Systemics, Cybernetics and Informatics 18, no. 2 (2020): 55–61.","ama":"Meyer M, Frank M, Massmann M, Dumitrescu R. Research and Consulting in Data-Driven Strategic Product Planning. Journal of Systemics, Cybernetics and Informatics. 2020;18(2):55-61.","apa":"Meyer, M., Frank, M., Massmann, M., & Dumitrescu, R. (2020). Research and Consulting in Data-Driven Strategic Product Planning. Journal of Systemics, Cybernetics and Informatics, 18(2), 55–61."},"language":[{"iso":"eng"}],"intvolume":" 18","_id":"19866","date_updated":"2022-01-06T06:54:14Z","issue":"2"},{"user_id":"67265","title":"Social interactions and asset pricing bubbles","author":[{"first_name":"Sören","full_name":"Steiger, Sören","last_name":"Steiger"},{"id":"67265","last_name":"Pelster","full_name":"Pelster, Matthias","orcid":" https://orcid.org/0000-0001-5740-2420","first_name":"Matthias"}],"publication":"Journal of Economic Behavior & Organization","department":[{"_id":"186"},{"_id":"578"}],"status":"public","date_created":"2020-10-06T06:17:16Z","publication_status":"published","volume":179,"publication_identifier":{"issn":["0167-2681"]},"intvolume":" 179","_id":"19895","date_updated":"2022-01-06T06:54:14Z","doi":"10.1016/j.jebo.2020.09.020","language":[{"iso":"eng"}],"type":"journal_article","year":"2020","citation":{"apa":"Steiger, S., & Pelster, M. (2020). Social interactions and asset pricing bubbles. Journal of Economic Behavior & Organization, 179, 503–522. https://doi.org/10.1016/j.jebo.2020.09.020","ama":"Steiger S, Pelster M. Social interactions and asset pricing bubbles. Journal of Economic Behavior & Organization. 2020;179:503-522. doi:10.1016/j.jebo.2020.09.020","chicago":"Steiger, Sören, and Matthias Pelster. “Social Interactions and Asset Pricing Bubbles.” Journal of Economic Behavior & Organization 179 (2020): 503–22. https://doi.org/10.1016/j.jebo.2020.09.020.","mla":"Steiger, Sören, and Matthias Pelster. “Social Interactions and Asset Pricing Bubbles.” Journal of Economic Behavior & Organization, vol. 179, 2020, pp. 503–22, doi:10.1016/j.jebo.2020.09.020.","bibtex":"@article{Steiger_Pelster_2020, title={Social interactions and asset pricing bubbles}, volume={179}, DOI={10.1016/j.jebo.2020.09.020}, journal={Journal of Economic Behavior & Organization}, author={Steiger, Sören and Pelster, Matthias}, year={2020}, pages={503–522} }","short":"S. Steiger, M. Pelster, Journal of Economic Behavior & Organization 179 (2020) 503–522.","ieee":"S. Steiger and M. Pelster, “Social interactions and asset pricing bubbles,” Journal of Economic Behavior & Organization, vol. 179, pp. 503–522, 2020."},"page":"503-522"},{"abstract":[{"text":"Most existing robot formation problems seek a target formation of a certain\r\nminimal and, thus, efficient structure. Examples include the Gathering\r\nand the Chain-Formation problem. In this work, we study formation problems that\r\ntry to reach a maximal structure, supporting for example an efficient\r\ncoverage in exploration scenarios. A recent example is the NASA Shapeshifter\r\nproject, which describes how the robots form a relay chain along which gathered\r\ndata from extraterrestrial cave explorations may be sent to a home base.\r\n As a first step towards understanding such maximization tasks, we introduce\r\nand study the Max-Chain-Formation problem, where $n$ robots are ordered along a\r\nwinding, potentially self-intersecting chain and must form a connected,\r\nstraight line of maximal length connecting its two endpoints. We propose and\r\nanalyze strategies in a discrete and in a continuous time model. In the\r\ndiscrete case, we give a complete analysis if all robots are initially\r\ncollinear, showing that the worst-case time to reach an\r\n$\\varepsilon$-approximation is upper bounded by $\\mathcal{O}(n^2 \\cdot \\log\r\n(n/\\varepsilon))$ and lower bounded by $\\Omega(n^2 \\cdot~\\log\r\n(1/\\varepsilon))$. If one endpoint of the chain remains stationary, this result\r\ncan be extended to the non-collinear case. If both endpoints move, we identify\r\na family of instances whose runtime is unbounded. For the continuous model, we\r\ngive a strategy with an optimal runtime bound of $\\Theta(n)$. Avoiding an\r\nunbounded runtime similar to the discrete case relies crucially on a\r\ncounter-intuitive aspect of the strategy: slowing down the endpoints while all\r\nother robots move at full speed. Surprisingly, we can show that a similar trick\r\ndoes not work in the discrete model.","lang":"eng"}],"user_id":"38705","author":[{"last_name":"Castenow","id":"38705","first_name":"Jannik","full_name":"Castenow, Jannik"},{"last_name":"Kling","first_name":"Peter","full_name":"Kling, Peter"},{"last_name":"Knollmann","id":"39241","first_name":"Till","orcid":"0000-0003-2014-4696","full_name":"Knollmann, Till"},{"first_name":"Friedhelm","full_name":"Meyer auf der Heide, Friedhelm","last_name":"Meyer auf der Heide","id":"15523"}],"publisher":"Springer","publication":"Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings","status":"public","date_created":"2020-10-06T07:27:10Z","volume":12514,"intvolume":" 12514","_id":"19899","citation":{"short":"J. Castenow, P. Kling, T. Knollmann, F. Meyer auf der Heide, in: S. Devismes , N. Mittal (Eds.), Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings, Springer, 2020, pp. 65–80.","ieee":"J. Castenow, P. Kling, T. Knollmann, and F. Meyer auf der Heide, “A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up,” in Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings, 2020, vol. 12514, pp. 65–80.","ama":"Castenow J, Kling P, Knollmann T, Meyer auf der Heide F. A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up. In: Devismes S, Mittal N, eds. Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings. Vol 12514. Lecture Notes in Computer Science (LNCS). Springer; 2020:65-80. doi:10.1007/978-3-030-64348-5_6","apa":"Castenow, J., Kling, P., Knollmann, T., & Meyer auf der Heide, F. (2020). A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up. In S. Devismes & N. Mittal (Eds.), Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings (Vol. 12514, pp. 65–80). Springer. https://doi.org/10.1007/978-3-030-64348-5_6","chicago":"Castenow, Jannik, Peter Kling, Till Knollmann, and Friedhelm Meyer auf der Heide. “A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up.” In Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings, edited by Stéphane Devismes and Neeraj Mittal, 12514:65–80. Lecture Notes in Computer Science (LNCS). Springer, 2020. https://doi.org/10.1007/978-3-030-64348-5_6.","bibtex":"@inproceedings{Castenow_Kling_Knollmann_Meyer auf der Heide_2020, series={Lecture Notes in Computer Science (LNCS)}, title={A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up}, volume={12514}, DOI={10.1007/978-3-030-64348-5_6}, booktitle={Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings}, publisher={Springer}, author={Castenow, Jannik and Kling, Peter and Knollmann, Till and Meyer auf der Heide, Friedhelm}, editor={Devismes , Stéphane and Mittal, Neeraj Editors}, year={2020}, pages={65–80}, collection={Lecture Notes in Computer Science (LNCS)} }","mla":"Castenow, Jannik, et al. “A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up.” Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings, edited by Stéphane Devismes and Neeraj Mittal, vol. 12514, Springer, 2020, pp. 65–80, doi:10.1007/978-3-030-64348-5_6."},"year":"2020","type":"conference","page":"65-80","external_id":{"arxiv":["2010.02043 "]},"title":"A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up","department":[{"_id":"63"}],"editor":[{"full_name":"Devismes , Stéphane ","first_name":"Stéphane ","last_name":"Devismes "},{"last_name":"Mittal","first_name":"Neeraj ","full_name":"Mittal, Neeraj "}],"publication_identifier":{"isbn":["978-3-030-64347-8"]},"publication_status":"published","date_updated":"2022-01-06T06:54:14Z","doi":"10.1007/978-3-030-64348-5_6","series_title":"Lecture Notes in Computer Science (LNCS)","language":[{"iso":"eng"}]},{"main_file_link":[{"url":"https://rdcu.be/b79aB"}],"page":"1363-1400","citation":{"short":"R.I. McLachlan, C. Offen, Foundations of Computational Mathematics 20 (2020) 1363–1400.","ieee":"R. I. McLachlan and C. Offen, “Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation,” Foundations of Computational Mathematics, vol. 20, no. 6, pp. 1363–1400, 2020.","apa":"McLachlan, R. I., & Offen, C. (2020). Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation. Foundations of Computational Mathematics, 20(6), 1363–1400. https://doi.org/10.1007/s10208-020-09454-z","ama":"McLachlan RI, Offen C. Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation. Foundations of Computational Mathematics. 2020;20(6):1363-1400. doi:10.1007/s10208-020-09454-z","chicago":"McLachlan, Robert I, and Christian Offen. “Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation.” Foundations of Computational Mathematics 20, no. 6 (2020): 1363–1400. https://doi.org/10.1007/s10208-020-09454-z.","mla":"McLachlan, Robert I., and Christian Offen. “Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation.” Foundations of Computational Mathematics, vol. 20, no. 6, 2020, pp. 1363–400, doi:10.1007/s10208-020-09454-z.","bibtex":"@article{McLachlan_Offen_2020, title={Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation}, volume={20}, DOI={10.1007/s10208-020-09454-z}, number={6}, journal={Foundations of Computational Mathematics}, author={McLachlan, Robert I and Offen, Christian}, year={2020}, pages={1363–1400} }"},"type":"journal_article","year":"2020","_id":"19938","intvolume":" 20","issue":"6","publication":"Foundations of Computational Mathematics","author":[{"last_name":"McLachlan","first_name":"Robert I","full_name":"McLachlan, Robert I"},{"last_name":"Offen","id":"85279","first_name":"Christian","orcid":"https://orcid.org/0000-0002-5940-8057","full_name":"Offen, Christian"}],"volume":20,"date_created":"2020-10-06T16:31:46Z","status":"public","extern":"1","abstract":[{"text":"We show that symplectic integrators preserve bifurcations of Hamiltonian boundary value problems and that nonsymplectic integrators do not. We provide a universal description of the breaking of umbilic bifurcations by nonysmplectic integrators. We discover extra structure induced from certain types of boundary value problems, including classical Dirichlet problems, that is useful to locate bifurcations. Geodesics connecting two points are an example of a Hamiltonian boundary value problem, and we introduce the jet-RATTLE method, a symplectic integrator that easily computes geodesics and their bifurcations. Finally, we study the periodic pitchfork bifurcation, a codimension-1 bifurcation arising in integrable Hamiltonian systems. It is not preserved by either symplectic on nonsymplectic integrators, but in some circumstances symplecticity greatly reduces the error. ","lang":"eng"}],"article_type":"original","user_id":"85279","language":[{"iso":"eng"}],"date_updated":"2022-01-06T06:54:14Z","doi":"10.1007/s10208-020-09454-z","department":[{"_id":"636"}],"publication_status":"published","title":"Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation"},{"_id":"19939","intvolume":" 33","issue":"5","main_file_link":[{"open_access":"1","url":"https://doi.org/10.1088/1361-6544/ab7293"}],"page":"2335-2363","year":"2020","type":"journal_article","citation":{"mla":"Kreusser, Lisa Maria, et al. “Detection of High Codimensional Bifurcations in Variational PDEs.” Nonlinearity, vol. 33, no. 5, 2020, pp. 2335–63, doi:10.1088/1361-6544/ab7293.","bibtex":"@article{Kreusser_McLachlan_Offen_2020, title={Detection of high codimensional bifurcations in variational PDEs}, volume={33}, DOI={10.1088/1361-6544/ab7293}, number={5}, journal={Nonlinearity}, author={Kreusser, Lisa Maria and McLachlan, Robert I and Offen, Christian}, year={2020}, pages={2335–2363} }","chicago":"Kreusser, Lisa Maria, Robert I McLachlan, and Christian Offen. “Detection of High Codimensional Bifurcations in Variational PDEs.” Nonlinearity 33, no. 5 (2020): 2335–63. https://doi.org/10.1088/1361-6544/ab7293.","ama":"Kreusser LM, McLachlan RI, Offen C. Detection of high codimensional bifurcations in variational PDEs. Nonlinearity. 2020;33(5):2335-2363. doi:10.1088/1361-6544/ab7293","apa":"Kreusser, L. M., McLachlan, R. I., & Offen, C. (2020). Detection of high codimensional bifurcations in variational PDEs. Nonlinearity, 33(5), 2335–2363. https://doi.org/10.1088/1361-6544/ab7293","ieee":"L. M. Kreusser, R. I. McLachlan, and C. Offen, “Detection of high codimensional bifurcations in variational PDEs,” Nonlinearity, vol. 33, no. 5, pp. 2335–2363, 2020.","short":"L.M. Kreusser, R.I. McLachlan, C. Offen, Nonlinearity 33 (2020) 2335–2363."},"extern":"1","article_type":"original","user_id":"85279","publication":"Nonlinearity","author":[{"first_name":"Lisa Maria","full_name":"Kreusser, Lisa Maria","last_name":"Kreusser"},{"last_name":"McLachlan","full_name":"McLachlan, Robert I","first_name":"Robert I"},{"id":"85279","last_name":"Offen","orcid":"https://orcid.org/0000-0002-5940-8057","full_name":"Offen, Christian","first_name":"Christian"}],"volume":33,"date_created":"2020-10-06T16:32:04Z","status":"public","date_updated":"2022-01-06T06:54:14Z","doi":"10.1088/1361-6544/ab7293","oa":"1","language":[{"iso":"eng"}],"title":"Detection of high codimensional bifurcations in variational PDEs","department":[{"_id":"636"}],"publication_identifier":{"issn":["0951-7715","1361-6544"]},"publication_status":"published"},{"language":[{"iso":"eng"}],"date_updated":"2022-01-06T06:54:16Z","oa":"1","publication_status":"published","place":"Palmerston North, New Zealand","title":"Analysis of Hamiltonian boundary value problems and symplectic integration","main_file_link":[{"url":"https://hdl.handle.net/10179/16155","open_access":"1"}],"type":"dissertation","year":"2020","citation":{"chicago":"Offen, Christian. Analysis of Hamiltonian Boundary Value Problems and Symplectic Integration. Palmerston North, New Zealand: Massey University, 2020.","ama":"Offen C. Analysis of Hamiltonian Boundary Value Problems and Symplectic Integration. Palmerston North, New Zealand: Massey University; 2020.","apa":"Offen, C. (2020). Analysis of Hamiltonian boundary value problems and symplectic integration. Palmerston North, New Zealand: Massey University.","mla":"Offen, Christian. Analysis of Hamiltonian Boundary Value Problems and Symplectic Integration. Massey University, 2020.","bibtex":"@book{Offen_2020, place={Palmerston North, New Zealand}, title={Analysis of Hamiltonian boundary value problems and symplectic integration}, publisher={Massey University}, author={Offen, Christian}, year={2020} }","short":"C. Offen, Analysis of Hamiltonian Boundary Value Problems and Symplectic Integration, Massey University, Palmerston North, New Zealand, 2020.","ieee":"C. Offen, Analysis of Hamiltonian boundary value problems and symplectic integration. Palmerston North, New Zealand: Massey University, 2020."},"supervisor":[{"first_name":"Robert I","full_name":"McLachlan, Robert I","last_name":"McLachlan"}],"_id":"19947","author":[{"last_name":"Offen","id":"85279","first_name":"Christian","full_name":"Offen, Christian","orcid":"https://orcid.org/0000-0002-5940-8057"}],"publisher":"Massey University","file_date_updated":"2020-10-07T14:01:58Z","file":[{"title":"Thesis Christian Offen","file_size":19465740,"access_level":"open_access","date_created":"2020-10-06T18:54:53Z","file_name":"ths_all_signatures.pdf","relation":"main_file","description":"A thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in\nMathematics at Massey University, Manawatū, New Zealand.","date_updated":"2020-10-07T14:01:58Z","content_type":"application/pdf","creator":"coffen","file_id":"19948"}],"alternative_title":["A thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mathematics at Massey University, Manawatū, New Zealand."],"status":"public","has_accepted_license":"1","date_created":"2020-10-06T18:56:44Z","extern":"1","abstract":[{"text":"Ordinary differential equations (ODEs) and partial differential equations (PDEs) arise\r\nin most scientific disciplines that make use of mathematical techniques. As exact solutions are in general not computable, numerical methods are used to obtain approximate\r\nsolutions. In order to draw valid conclusions from numerical computations, it is crucial\r\nto understand which qualitative aspects numerical solutions have in common with the\r\nexact solution. Symplecticity is a subtle notion that is related to a rich family of geometric properties of Hamiltonian systems. While the effects of preserving symplecticity\r\nunder discretisation on long-term behaviour of motions is classically well known, in this\r\nthesis\r\n(a) the role of symplecticity for the bifurcation behaviour of solutions to Hamiltonian\r\nboundary value problems is explained. In parameter dependent systems at a bifurcation\r\npoint the solution set to a boundary value problem changes qualitatively. Bifurcation\r\nproblems are systematically translated into the framework of classical catastrophe theory. It is proved that existing classification results in catastrophe theory apply to\r\npersistent bifurcations of Hamiltonian boundary value problems. Further results for\r\nsymmetric settings are derived.\r\n(b) It is proved that to preserve generic bifurcations under discretisation it is necessary and sufficient to preserve the symplectic structure of the problem.\r\n(c) The catastrophe theory framework for Hamiltonian ODEs is extended to PDEs\r\nwith variational structure. Recognition equations for A-series singularities for functionals on Banach spaces are derived and used in a numerical example to locate high-codimensional bifurcations.\r\n(d) The potential of symplectic integration for infinite-dimensional Lie-Poisson systems (Burgers’ equation, KdV, fluid equations, . . . ) using Clebsch variables is analysed.\r\nIt is shown that the advantages of symplectic integration can outweigh the disadvantages of integrating over a larger phase space introduced by a Clebsch representation.\r\n(e) Finally, the preservation of variational structure of symmetric solutions in multisymplectic PDEs by multisymplectic integrators on the example of (phase-rotating)\r\ntravelling waves in the nonlinear wave equation is discussed.","lang":"eng"}],"ddc":["510"],"user_id":"85279"},{"_id":"19953","intvolume":" 129","conference":{"location":"Bangkok, Thailand","start_date":"2020-11-18","name":"Asian Conference on Machine Learning","end_date":"2020-11-20"},"citation":{"short":"C. Damke, V. Melnikov, E. Hüllermeier, in: S. Jialin Pan, M. Sugiyama (Eds.), Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020), PMLR, Bangkok, Thailand, 2020, pp. 49–64.","ieee":"C. Damke, V. Melnikov, and E. Hüllermeier, “A Novel Higher-order Weisfeiler-Lehman Graph Convolution,” in Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020), Bangkok, Thailand, 2020, vol. 129, pp. 49–64.","apa":"Damke, C., Melnikov, V., & Hüllermeier, E. (2020). A Novel Higher-order Weisfeiler-Lehman Graph Convolution. In S. Jialin Pan & M. Sugiyama (Eds.), Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020) (Vol. 129, pp. 49–64). Bangkok, Thailand: PMLR.","ama":"Damke C, Melnikov V, Hüllermeier E. A Novel Higher-order Weisfeiler-Lehman Graph Convolution. In: Jialin Pan S, Sugiyama M, eds. Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020). Vol 129. Proceedings of Machine Learning Research. Bangkok, Thailand: PMLR; 2020:49-64.","chicago":"Damke, Clemens, Vitaly Melnikov, and Eyke Hüllermeier. “A Novel Higher-Order Weisfeiler-Lehman Graph Convolution.” In Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020), edited by Sinno Jialin Pan and Masashi Sugiyama, 129:49–64. Proceedings of Machine Learning Research. Bangkok, Thailand: PMLR, 2020.","bibtex":"@inproceedings{Damke_Melnikov_Hüllermeier_2020, place={Bangkok, Thailand}, series={Proceedings of Machine Learning Research}, title={A Novel Higher-order Weisfeiler-Lehman Graph Convolution}, volume={129}, booktitle={Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020)}, publisher={PMLR}, author={Damke, Clemens and Melnikov, Vitaly and Hüllermeier, Eyke}, editor={Jialin Pan, Sinno and Sugiyama, MasashiEditors}, year={2020}, pages={49–64}, collection={Proceedings of Machine Learning Research} }","mla":"Damke, Clemens, et al. “A Novel Higher-Order Weisfeiler-Lehman Graph Convolution.” Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020), edited by Sinno Jialin Pan and Masashi Sugiyama, vol. 129, PMLR, 2020, pp. 49–64."},"year":"2020","type":"conference","page":"49-64","abstract":[{"text":"Current GNN architectures use a vertex neighborhood aggregation scheme, which limits their discriminative power to that of the 1-dimensional Weisfeiler-Lehman (WL) graph isomorphism test. Here, we propose a novel graph convolution operator that is based on the 2-dimensional WL test. We formally show that the resulting 2-WL-GNN architecture is more discriminative than existing GNN approaches. This theoretical result is complemented by experimental studies using synthetic and real data. On multiple common graph classification benchmarks, we demonstrate that the proposed model is competitive with state-of-the-art graph kernels and GNNs.","lang":"eng"}],"user_id":"48192","ddc":["006"],"file":[{"date_updated":"2020-10-08T11:21:00Z","content_type":"application/pdf","relation":"main_file","file_size":771137,"creator":"cdamke","file_id":"19954","access_level":"open_access","date_created":"2020-10-08T10:54:48Z","file_name":"damke20.pdf"},{"file_id":"19955","creator":"cdamke","file_size":613163,"relation":"supplementary_material","content_type":"application/pdf","date_updated":"2020-10-08T11:24:29Z","date_created":"2020-10-08T10:54:59Z","file_name":"damke20-supp.pdf","access_level":"open_access"}],"author":[{"first_name":"Clemens","orcid":"0000-0002-0455-0048","full_name":"Damke, Clemens","last_name":"Damke","id":"48192"},{"last_name":"Melnikov","id":"58747","first_name":"Vitaly","full_name":"Melnikov, Vitaly"},{"last_name":"Hüllermeier","id":"48129","first_name":"Eyke","full_name":"Hüllermeier, Eyke"}],"quality_controlled":"1","publisher":"PMLR","file_date_updated":"2020-10-08T11:24:29Z","publication":"Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020)","keyword":["graph neural networks","Weisfeiler-Lehman test","cycle detection"],"has_accepted_license":"1","status":"public","date_created":"2020-10-08T10:48:38Z","volume":129,"date_updated":"2022-01-06T06:54:17Z","oa":"1","series_title":"Proceedings of Machine Learning Research","language":[{"iso":"eng"}],"place":"Bangkok, Thailand","external_id":{"arxiv":["2007.00346"]},"title":"A Novel Higher-order Weisfeiler-Lehman Graph Convolution","department":[{"_id":"355"}],"editor":[{"last_name":"Jialin Pan","first_name":"Sinno","full_name":"Jialin Pan, Sinno"},{"last_name":"Sugiyama","full_name":"Sugiyama, Masashi","first_name":"Masashi"}],"publication_status":"published"},{"intvolume":" 50","_id":"19976","type":"conference_editor","citation":{"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.","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.","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} }","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.","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"},"year":"2020","page":"280-285","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"],"doi":"10.1016/j.promfg.2020.08.052","date_updated":"2022-01-06T06:54:17Z","language":[{"iso":"eng"}],"series_title":"Procedia Manufacturing","title":"Process design for the forming of semi-tubular self-piercing rivets made of high nitrogen steel","editor":[{"full_name":"Kuball, Clara-Maria","first_name":"Clara-Maria","last_name":"Kuball"},{"last_name":"Uhe","id":"38131","first_name":"Benedikt","full_name":"Uhe, Benedikt"},{"first_name":"Gerson","orcid":"0000-0002-2763-1246","full_name":"Meschut, Gerson","last_name":"Meschut","id":"32056"},{"last_name":"Merklein","first_name":"Marion","full_name":"Merklein, Marion"}],"publication_status":"published","department":[{"_id":"157"}]},{"date_updated":"2022-01-06T06:54:18Z","_id":"19999","language":[{"iso":"eng"}],"supervisor":[{"full_name":"Wehrheim, Heike","first_name":"Heike","id":"573","last_name":"Wehrheim"}],"year":"2020","citation":{"ama":"Mayer S. Optimierung von JMCTest Beim Testen von Inter Method Contracts. Universität Paderborn; 2020.","apa":"Mayer, S. (2020). Optimierung von JMCTest beim Testen von Inter Method Contracts. Universität Paderborn.","chicago":"Mayer, Stefan. Optimierung von JMCTest Beim Testen von Inter Method Contracts. Universität Paderborn, 2020.","mla":"Mayer, Stefan. Optimierung von JMCTest Beim Testen von Inter Method Contracts. Universität Paderborn, 2020.","bibtex":"@book{Mayer_2020, title={Optimierung von JMCTest beim Testen von Inter Method Contracts}, publisher={Universität Paderborn}, author={Mayer, Stefan}, year={2020} }","short":"S. Mayer, Optimierung von JMCTest Beim Testen von Inter Method Contracts, Universität Paderborn, 2020.","ieee":"S. Mayer, Optimierung von JMCTest beim Testen von Inter Method Contracts. Universität Paderborn, 2020."},"type":"bachelorsthesis","user_id":"477","title":"Optimierung von JMCTest beim Testen von Inter Method Contracts","status":"public","date_created":"2020-10-15T05:15:46Z","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Project Area B","_id":"3"},{"name":"SFB 901 - Subproject B3","_id":"11"}],"author":[{"last_name":"Mayer","first_name":"Stefan","full_name":"Mayer, Stefan"}],"publisher":"Universität Paderborn","department":[{"_id":"7"},{"_id":"77"}]}]