TY - CONF
AB - Faults in the realization and usage of cyber-physical systems can cause significant security issues. Attackers might exploit vulnerabilities in the physical configurations, control systems, or accessibility through internet connections. For CPS, two challenges are combined: Firstly, discipline-specific security measures should be applied. Secondly, new measures have to be created to cover interdisciplinary impacts. For instance, faulty software configurations in cyber-physical production systems (CPPS) might allow attackers to manipulate the correct control of production processes impacting the quality of end products. From liability and publicity perspective, a worst-case scenario is that such a corrupted product is delivered to a customer. In this context, security-oriented fault-tolerance in Systems Engineering (SE) requires measures to evaluate interdisciplinary system designs with regard to potential scenarios of attacks. The paper at hand contributes a conceptual threat modelling approach to cover potential attack scenarios. The approach can be used to derive both system-level and discipline-specific security solutions. As an application case, issues are focused on which attackers intend to exploit vulnerabilities in a CPPS. The goal is to support systems engineers in verification and validation tasks regarding security-oriented fault-tolerance.
AU - Gräßler, Iris
AU - Bodden, Eric
AU - Pottebaum, Jens
AU - Geismann, Johannes
AU - Roesmann, Daniel
ID - 23521
T2 - Advanced, Contemporary Control, Advances in Intelligent Systems and Computing
TI - Security-Oriented Fault-Tolerance in Systems Engineering: A Conceptual Threat Modelling Approach for Cyber-Physical Production Systems
VL - 1196
ER -
TY - JOUR
AB - AbstractThe value of models is well recognised in product and systems engineering. Modelling languages and diagrams are used to capture mental models and to handle model complexity. Literature research indicates that there are only very few approaches to utilise the potential of virtual and augmented reality for supporting tasks in model based (systems) engineering. The paper at hand contributes a new morphology of intuitive interaction for Immersive Abstraction as a holistic approach to extend that coverage. It presents a holistic framework to categorise solutions and future research directions.
AU - Gräßler, Iris
AU - Pottebaum, Jens
ID - 23468
JF - Proceedings of the Design Society: DESIGN Conference; 26. - 29. Okt. 2020
SN - 2633-7762
TI - Immersive Abstraction: A new Morphology of Intuitive Interaction with System Models
VL - Band 1
ER -
TY - CONF
AU - Gräßler, Iris
AU - Roesmann, Daniel
AU - Pottebaum, Jens
ID - 23520
SN - 978-3-936804-27-0
T2 - Frühjahrskongress 2020 - Digitaler Wandel, digitale Arbeit, digitaler Mensch?; 16. - 18. Mrz. 2020
TI - Entwicklung eines Prüfstands für die Bewertung von kompetenzbildenden Assistenzsystemen in Cyber-physischen Produktionssystemen
ER -
TY - CONF
AU - Gräßler, Iris
AU - Pottebaum, Jens
AU - Taplick, Patrick
AU - Roesmann, Daniel
AU - Kamann, Markus
ID - 23519
SN - 978-3-936804-27-0
T2 - Frühjahrskongress 2020 - Digitaler Wandel, digitale Arbeit, digitaler Mensch?; 16. - 18. Mrz. 2020
TI - Produktdatenbasiertes, arbeitsgebundenes Lernen für und mit Augmented Reality in der Instandhaltung
ER -
TY - JOUR
AU - Pottebaum, Jens
AU - Gräßler, Iris
ID - 23530
IS - (11-12)
JF - Konstruktion
TI - Informationsqualität in der Produktentwicklung: Modellbasiertes Systems Engineering mit expliziter Berücksichtigung von Unsicherheit
VL - 72 (11-12)
ER -
TY - GEN
AU - Meyberg, Sora
AU - Treder, Alexandra
ID - 48941
TI - Mit Methoden der Drama- und Erzählpädagogik Fremdsprachen lernen
ER -
TY - CHAP
AU - Schulze, Max
ED - Gliem, Vera
ED - Strsembski, Stephan
ID - 48963
KW - Editionen
KW - Kunst
KW - Fotografie
KW - Siebdruck
KW - Farbattentat
T2 - Provinz Editionen 2011-2020
TI - Hunger (Eduardo Chillida) und Swingcolor
ER -
TY - CHAP
AU - Schulze, Max
ED - Theewen, Gerhard
ID - 48957
SN - 978-3-89770-523-4
T2 - Salon #15
TI - Der Wunsch zu verschwinden
ER -
TY - BOOK
AU - Hartung, Olaf
ID - 29817
SN - 978-3-17-022637-1
TI - Museen und Geschichtsunterricht
ER -
TY - CHAP
AU - Moritz, Tilman
ED - Stiegemann, Christoph
ID - 49006
SN - 978-3-7319-0956-9
T2 - Peter Paul Rubens und der Barock im Norden. Katalog zur Ausstellung im Erzbischöflichen Diözesanmuseum Paderborn
TI - Mehr Barock wagen. Neuordnungen des Fürstbistums Paderborn aus dem Dreißigjährigen Krieg
ER -
TY - GEN
AU - Moritz, Tilman
ID - 49018
T2 - Rottenburger Jahrbuch für Kirchengeschichte
TI - P. O. Adiele: The Popes, the Catholic Church and the Transatlantic Enslavement of Black Africans 1418–1839. Hildesheim u. a. 2017
VL - 38
ER -
TY - CHAP
AB - In this work we review the novel framework for the computation of finite dimensional invariant sets of infinite dimensional dynamical systems developed in [6] and [36]. By utilizing results on embedding techniques for infinite dimensional systems we extend a classical subdivision scheme [8] as well as a continuation algorithm [7] for the computation of attractors and invariant manifolds of finite dimensional systems to the infinite dimensional case. We show how to implement this approach for the analysis of delay differential equations and partial differential equations and illustrate the feasibility of our implementation by computing the attractor of the Mackey-Glass equation and the unstable manifold of the one-dimensional Kuramoto-Sivashinsky equation.
AU - Gerlach, Raphael
AU - Ziessler, Adrian
ED - Junge, Oliver
ED - Schütze, Oliver
ED - Ober-Blöbaum, Sina
ED - Padberg-Gehle, Kathrin
ID - 17994
SN - 2198-4182
T2 - Advances in Dynamics, Optimization and Computation
TI - The Approximation of Invariant Sets in Infinite Dimensional Dynamical Systems
VL - 304
ER -
TY - JOUR
AB - We investigate self-adjoint matrices A∈Rn,n with respect to their equivariance properties. We show in particular that a matrix is self-adjoint if and only if it is equivariant with respect to the action of a group Γ2(A)⊂O(n) which is isomorphic to ⊗nk=1Z2. If the self-adjoint matrix possesses multiple eigenvalues – this may, for instance, be induced by symmetry properties of an underlying dynamical system – then A is even equivariant with respect to the action of a group Γ(A)≃∏ki=1O(mi) where m1,…,mk are the multiplicities of the eigenvalues λ1,…,λk of A. We discuss implications of this result for equivariant bifurcation problems, and we briefly address further applications for the Procrustes problem, graph symmetries and Taylor expansions.
AU - Dellnitz, Michael
AU - Gebken, Bennet
AU - Gerlach, Raphael
AU - Klus, Stefan
ID - 16712
IS - 2
JF - Dynamical Systems
SN - 1468-9367
TI - On the equivariance properties of self-adjoint matrices
VL - 35
ER -
TY - BOOK
AU - Schulze, Max
ID - 49070
TI - Vandalene
ER -
TY - CONF
AB - In this paper we present our system for the detection and classification of acoustic scenes and events (DCASE) 2020 Challenge Task 4: Sound event detection and separation in domestic environments. We introduce two new models: the forward-backward convolutional recurrent neural network (FBCRNN) and the tag-conditioned convolutional neural network (CNN). The FBCRNN employs two recurrent neural network (RNN) classifiers sharing the same CNN for preprocessing. With one RNN processing a recording in forward direction and the other in backward direction, the two networks are trained to jointly predict audio tags, i.e., weak labels, at each time step within a recording, given that at each time step they have jointly processed the whole recording. The proposed training encourages the classifiers to tag events as soon as possible. Therefore, after training, the networks can be applied to shorter audio segments of, e.g., 200ms, allowing sound event detection (SED). Further, we propose a tag-conditioned CNN to complement SED. It is trained to predict strong labels while using (predicted) tags, i.e., weak labels, as additional input. For training pseudo strong labels from a FBCRNN ensemble are used. The presented system scored the fourth and third place in the systems and teams rankings, respectively. Subsequent improvements allow our system to even outperform the challenge baseline and winner systems in average by, respectively, 18.0% and 2.2% event-based F1-score on the validation set. Source code is publicly available at https://github.com/fgnt/pb_sed.
AU - Ebbers, Janek
AU - Haeb-Umbach, Reinhold
ID - 20753
T2 - Proceedings of the Detection and Classification of Acoustic Scenes and Events 2020 Workshop (DCASE2020)
TI - Forward-Backward Convolutional Recurrent Neural Networks and Tag-Conditioned Convolutional Neural Networks for Weakly Labeled Semi-Supervised Sound Event Detection
ER -
TY - BOOK
AU - Schneider, Martin
AU - Sadowski, Dieter
AU - Frick, Bernd
AU - Warning, Susanne
ID - 21566
TI - Personalökonomie und Personalpolitik: Grundlagen einer evidenzbasierten Praxis
ER -
TY - JOUR
AU - Schneider, Martin
ID - 18426
JF - Erzähltes Geld: Finanzmärkte und Krisen in Literatur, Film und Medien
SN - 978-3-8260-6930-7
TI - Gier und andere Tugenden: Widersprüchliche Bewertungen der Marktwirtschaft ain Oliver Stones "Wall Street"
ER -
TY - JOUR
AU - Meier, Heiko
AU - Auer, Thorsten Fabian
AU - Sennefelder, Lisa
ID - 34861
IS - 1
JF - Journal Gesundheitsförderung für Akteurinnen und Akteure aus Politik, Wissenschaft und Praxis
SN - 2195-9552
TI - Der Einfluss von gesundheitsförderlichen Maßnahmen auf die Kommunikationsstrukturen: Nutzen für die Arbeitsproduktivität?
ER -
TY - JOUR
AU - Gretz, Daniela
ID - 49185
JF - JbRG
TI - Zwischen romantischem Fragment und Skizze/n der Moderne. Zum medialen Realismus von Wilhelm Raabes Wer kann es wenden?
VL - 61
ER -
TY - JOUR
AB - Beziehungen zwischen Erwachsenen und ihren Eltern sind durch Interdependenzen und Dependenzen gekennzeichnet. Während das Zusammenleben von Familien mit Kindern im mittleren Erwachsenenalter dabei ganz überwiegend durch Interdependenz geprägt ist, nehmen im Alter Dependenzen durch gesundheitliche Beeinträchtigungen der Eltern zu. Mit Blick darauf werden im Artikel behaviorale, kognitive und emotionale Merkmale von Eltern-Kind-Beziehungen erläutert und theoretisch in zentrale Konzepte eingebettet. Das Verhalten ist durch Solidarität zwischen den Generationen, aber auch durch Aspekte des Einflusses innerhalb der Beziehung und aufeinander, gekennzeichnet. Um Familienkognitionen zu beschreiben, werden die verwandten Konzepte der Individuation und der filialen Reife herangezogen. Verhalten, wie auch Kognitionen, sind eng mit dem dritten Beziehungsmerkmal, der Affektivität verknüpft, das neben positiven auch negative Gefühle sowie Ambivalenzen umfasst.
AU - Buhl, Heike M.
AU - Sommer, Sabrina
ID - 49278
IS - 2
JF - Psychotherapie im Alter
KW - General Earth and Planetary Sciences
KW - General Environmental Science
SN - 1613-2637
TI - Intergenerationelle Beziehungen in der Familie
VL - 16
ER -
TY - BOOK
ED - Breuer, Saskia
ED - Hillebrand, Sonja
ID - 49329
TI - Das Leichte Lexikon des Glaubens
ER -
TY - CONF
AU - Moritzer, Elmar
AU - Hillemeyer, Johannes
ID - 24247
T2 - 73rd Annual Assembly of International Institute of Welding (IIW) and International Conference
TI - Material Specific Predicting of the Optimal Joining Parameters for the Screw Blind Rivet Joining Process
ER -
TY - CHAP
AU - Kammeyer, Katharina
ED - Knauth, Thorsten
ED - Möller, Rainer
ED - Pithan, Annabelle
ID - 49378
T2 - Inklusive Religionspädagogik der Vielfalt. Konzeptionelle Grundlagen und didaktische Konkretionen
TI - Differenz
VL - 42
ER -
TY - JOUR
AU - Mandrella, M.
AU - Trang, S.
AU - Kolbe, L. M.
ID - 49470
IS - 2
JF - Journal of the Association for Information Systems
TI - Synthesizing and Integrating Research on IT-Based Value Co-Creation: A Meta-Analysis
VL - 21
ER -
TY - JOUR
AU - Masuch, K.
AU - Hengstler, S.
AU - Trang, S.
AU - Brendel, A.
ID - 49466
IS - 1
JF - AIS Transactions on Replication Research
TI - Replication of the Unified Model of Information Security Policy Compliance
VL - 6
ER -
TY - JOUR
AU - Brendel, B.
AU - Greulich, S.
AU - Trang, S.
AU - Niederman, F.
ID - 49465
IS - 1
JF - AIS Transactions on Replication Research
TI - Towards a Greater Diversity of Replication Studies
VL - 6
ER -
TY - JOUR
AU - Trang, S.
AU - Trenz, M.
AU - Weiger, W.
AU - Tarafdar, M.
AU - Cheung, C.
ID - 49467
JF - European Journal of Information Systems
TI - One app to trace them all? Examining app specifications for mass acceptance of contact-tracing apps
VL - 29
ER -
TY - CHAP
AU - Schumacher, Jan
AU - Rezat, Sebastian
ED - Kadunz, Gert
ID - 44685
SN - 9783662611937
T2 - Zeichen und Sprache im Mathematikunterricht: Semiotik in Theorie und Praxis
TI - Rekonstruktion diagrammatischen Schließens beim Erlernen der Subtraktion negativer Zahlen
ER -
TY - BOOK
AU - Halding, Ole
AU - Hartung, Olaf
ID - 29823
SN - 979-8-6046-6598-5
TI - Die Eigenen täuschen: Szenen eines Kriegsausbruchs nach wahrer Geschichte
ER -
TY - CONF
AU - Krings, Sarah Claudia
AU - Yigitbas, Enes
AU - Jovanovikj, Ivan
AU - Sauer, Stefan
AU - Engels, Gregor
ID - 16790
SN - 978-1-4503-7984-7/20/06
T2 - Proceedings of the 12th ACM SIGCHI Symposium on Engineering Interactive Computing Systems (EICS 2020)
TI - Development Framework for Context-Aware Augmented Reality Applications
ER -
TY - JOUR
AU - Hagemann, Philipp
AU - Kreißl, Steffen
AU - Reinke, Paul
AU - Wagner, Alexander
ID - 47828
JF - Tierstudien
TI - "[...] eine Sammelstelle für Tierseelenkunde". Wie eine Wissenschaftszeitschrift um 1900 die Mensch/Tier-Grenze neu zu ordnen versucht
VL - 18
ER -
TY - CHAP
AU - Sloane, Hannah
AU - Kremer, H.-Hugo
ED - Fuge, Juliane
ED - Kremer, H.-Hugo
ID - 26021
T2 - Mentoring in Hochschuldidaktik und -praxis - Eine Reflexion wissenschaftlicher Erkenntnisse und praktischer Erfahrungen
TI - Peer Mentoring an der Fakultät für Wirtschaftswissenschaften - Einblicke in ein Schulungskonzept für Peer Mentor*innen
VL - 2
ER -
TY - CHAP
AU - Meyer zu Hörste-Bührer, Raphaela
ED - Focken, F.-E.
ED - van Oorschot, F.
ED - Breu, C.
ID - 49533
T2 - Schriftbindung evangelischer Theologie, Forum Theologische Literaturzeitung 37
TI - Gotteswort und Menschenwort.
ER -
TY - CHAP
AU - Meyer zu Hörste-Bührer, Raphaela
ED - Focken, F.-E.
ED - van Oorschot , F.
ED - Breu, C.
ID - 49535
T2 - Schriftbindung evangelischer Theologie, Forum Theologische Literaturzeitung 37
TI - Autorität der Schrift im Verhältnis zu Rezeptionsprozessen.
ER -
TY - CHAP
AU - Meyer zu Hörste-Bührer, Raphaela
ED - Focken, F.-E.
ED - van Oorschot, F.
ED - Breu, C.
ID - 49532
T2 - Schriftbindung evangelischer Theologie, Forum Theologische Literaturzeitung 37
TI - Schrift und Schriftauslegung in relationaler Perspektive.
ER -
TY - CHAP
AU - Meyer zu Hörste-Bührer, Raphaela
ED - Focken, F.-E.
ED - van Oorschot, F.
ED - Breu, C.
ID - 49534
T2 - Schriftbindung evangelischer Theologie, Forum Theologische Literaturzeitung 37
TI - Pluralität und Einheit der Schrift.
ER -
TY - BOOK
ED - Focken, F.-E.
ED - van Oorschot, F.
ED - Breu, C.
ED - Bührer, W.
ED - Stamer, T.
ED - Zeller, K.
ED - Ziethe, C.
ID - 49522
TI - Schriftbindung evangelischer Theologie. Theorieelemente aus interdisziplinären Gesprächen.
ER -
TY - JOUR
AU - Meyer zu Hörste-Bührer, Raphaela
ID - 49531
JF - ides quaerens intellectum. Festschrift für Walter Dietz.
TI - Die Gewalt der Ethik? Überlegungen zu Ausübung und Legitimation struktureller Gewalt durch die theologische Ethik.
ER -
TY - JOUR
AU - Meyer zu Hörste-Bührer, Raphaela
ID - 49544
JF - Zeitschrift für Evangelische Ethik 64/1
TI - Digitale antike Ethik – Gründung des „Journals of Ethics in Antiquity and Christianity (JEAC)“
ER -
TY - CONF
AB - Dynamic optimization problems have gained significant attention in evolutionary computation as evolutionary algorithms (EAs) can easily adapt to changing environments. We show that EAs can solve the graph coloring problem for bipartite graphs more efficiently by using dynamic optimization. In our approach the graph instance is given incrementally such that the EA can reoptimize its coloring when a new edge introduces a conflict. We show that, when edges are inserted in a way that preserves graph connectivity, Randomized Local Search (RLS) efficiently finds a proper 2-coloring for all bipartite graphs. This includes graphs for which RLS and other EAs need exponential expected time in a static optimization scenario. We investigate different ways of building up the graph by popular graph traversals such as breadth-first-search and depth-first-search and analyse the resulting runtime behavior. We further show that offspring populations (e. g. a (1 + {$\lambda$}) RLS) lead to an exponential speedup in {$\lambda$}. Finally, an island model using 3 islands succeeds in an optimal time of {$\Theta$}(m) on every m-edge bipartite graph, outperforming offspring populations. This is the first example where an island model guarantees a speedup that is not bounded in the number of islands.
AU - Bossek, Jakob
AU - Neumann, Frank
AU - Peng, Pan
AU - Sudholt, Dirk
ID - 48847
KW - dynamic optimization
KW - evolutionary algorithms
KW - running time analysis
KW - theory
SN - 978-1-4503-7128-5
T2 - Proceedings of the Genetic and Evolutionary Computation Conference
TI - More Effective Randomized Search Heuristics for Graph Coloring through Dynamic Optimization
ER -
TY - CONF
AB - One-shot optimization tasks require to determine the set of solution candidates prior to their evaluation, i.e., without possibility for adaptive sampling. We consider two variants, classic one-shot optimization (where our aim is to find at least one solution of high quality) and one-shot regression (where the goal is to fit a model that resembles the true problem as well as possible). For both tasks it seems intuitive that well-distributed samples should perform better than uniform or grid-based samples, since they show a better coverage of the decision space. In practice, quasi-random designs such as Latin Hypercube Samples and low-discrepancy point sets are indeed very commonly used designs for one-shot optimization tasks. We study in this work how well low star discrepancy correlates with performance in one-shot optimization. Our results confirm an advantage of low-discrepancy designs, but also indicate the correlation between discrepancy values and overall performance is rather weak. We then demonstrate that commonly used designs may be far from optimal. More precisely, we evolve 24 very specific designs that each achieve good performance on one of our benchmark problems. Interestingly, we find that these specifically designed samples yield surprisingly good performance across the whole benchmark set. Our results therefore give strong indication that significant performance gains over state-of-the-art one-shot sampling techniques are possible, and that evolutionary algorithms can be an efficient means to evolve these.
AU - Bossek, Jakob
AU - Doerr, Carola
AU - Kerschke, Pascal
AU - Neumann, Aneta
AU - Neumann, Frank
ID - 48849
KW - Continuous optimization
KW - Fully parallel search
KW - One-shot optimization
KW - Regression
KW - Surrogate-assisted optimization
SN - 978-3-030-58111-4
T2 - Parallel Problem Solving from Nature (PPSN XVI)
TI - Evolving Sampling Strategies for One-Shot Optimization Tasks
ER -
TY - CONF
AB - Several important optimization problems in the area of vehicle routing can be seen as variants of the classical Traveling Salesperson Problem (TSP). In the area of evolutionary computation, the Traveling Thief Problem (TTP) has gained increasing interest over the last 5 years. In this paper, we investigate the effect of weights on such problems, in the sense that the cost of traveling increases with respect to the weights of nodes already visited during a tour. This provides abstractions of important TSP variants such as the Traveling Thief Problem and time dependent TSP variants, and allows to study precisely the increase in difficulty caused by weight dependence. We provide a 3.59-approximation for this weight dependent version of TSP with metric distances and bounded positive weights. Furthermore, we conduct experimental investigations for simple randomized local search with classical mutation operators and two variants of the state-of-the-art evolutionary algorithm EAX adapted to the weighted TSP. Our results show the impact of the node weights on the position of the nodes in the resulting tour.
AU - Bossek, Jakob
AU - Casel, Katrin
AU - Kerschke, Pascal
AU - Neumann, Frank
ID - 48851
KW - dynamic optimization
KW - evolutionary algorithms
KW - running time analysis
KW - theory
SN - 978-1-4503-7128-5
T2 - Proceedings of the Genetic and Evolutionary Computation Conference
TI - The Node Weight Dependent Traveling Salesperson Problem: Approximation Algorithms and Randomized Search Heuristics
ER -
TY - CONF
AB - In practice, e.g. in delivery and service scenarios, Vehicle-Routing-Problems (VRPs) often imply repeated decision making on dynamic customer requests. As in classical VRPs, tours have to be planned short while the number of serviced customers has to be maximized at the same time resulting in a multi-objective problem. Beyond that, however, dynamic requests lead to the need for re-planning of not yet realized tour parts, while already realized tour parts are irreversible. In this paper we study this type of bi-objective dynamic VRP including sequential decision making and concurrent realization of decisions. We adopt a recently proposed Dynamic Evolutionary Multi-Objective Algorithm (DEMOA) for a related VRP problem and extend it to the more realistic (here considered) scenario of multiple vehicles. We empirically show that our DEMOA is competitive with a multi-vehicle offline and clairvoyant variant of the proposed DEMOA as well as with the dynamic single-vehicle approach proposed earlier.
AU - Bossek, Jakob
AU - Grimme, Christian
AU - Trautmann, Heike
ID - 48845
KW - decision making
KW - dynamic optimization
KW - evolutionary algorithms
KW - multi-objective optimization
KW - vehicle routing
SN - 978-1-4503-7128-5
T2 - Proceedings of the Genetic and Evolutionary Computation Conference
TI - Dynamic Bi-Objective Routing of Multiple Vehicles
ER -
TY - CONF
AB - The Traveling-Salesperson-Problem (TSP) is arguably one of the best-known NP-hard combinatorial optimization problems. The two sophisticated heuristic solvers LKH and EAX and respective (restart) variants manage to calculate close-to optimal or even optimal solutions, also for large instances with several thousand nodes in reasonable time. In this work we extend existing benchmarking studies by addressing anytime behaviour of inexact TSP solvers based on empirical runtime distributions leading to an increased understanding of solver behaviour and the respective relation to problem hardness. It turns out that performance ranking of solvers is highly dependent on the focused approximation quality. Insights on intersection points of performances offer huge potential for the construction of hybridized solvers depending on instance features. Moreover, instance features tailored to anytime performance and corresponding performance indicators will highly improve automated algorithm selection models by including comprehensive information on solver quality.
AU - Bossek, Jakob
AU - Kerschke, Pascal
AU - Trautmann, Heike
ID - 48844
T2 - 2020 IEEE Congress on Evolutionary Computation (CEC)
TI - Anytime Behavior of Inexact TSP Solvers and Perspectives for Automated Algorithm Selection
ER -
TY - CONF
AB - Sequential model-based optimization (SMBO) approaches are algorithms for solving problems that require computationally or otherwise expensive function evaluations. The key design principle of SMBO is a substitution of the true objective function by a surrogate, which is used to propose the point(s) to be evaluated next. SMBO algorithms are intrinsically modular, leaving the user with many important design choices. Significant research efforts go into understanding which settings perform best for which type of problems. Most works, however, focus on the choice of the model, the acquisition function, and the strategy used to optimize the latter. The choice of the initial sampling strategy, however, receives much less attention. Not surprisingly, quite diverging recommendations can be found in the literature. We analyze in this work how the size and the distribution of the initial sample influences the overall quality of the efficient global optimization (EGO) algorithm, a well-known SMBO approach. While, overall, small initial budgets using Halton sampling seem preferable, we also observe that the performance landscape is rather unstructured. We furthermore identify several situations in which EGO performs unfavorably against random sampling. Both observations indicate that an adaptive SMBO design could be beneficial, making SMBO an interesting test-bed for automated algorithm design.
AU - Bossek, Jakob
AU - Doerr, Carola
AU - Kerschke, Pascal
ID - 48850
KW - continuous black-box optimization
KW - design of experiments
KW - initial design
KW - sequential model-based optimization
SN - 978-1-4503-7128-5
T2 - Proceedings of the Genetic and Evolutionary Computation Conference
TI - Initial Design Strategies and Their Effects on Sequential Model-Based Optimization: An Exploratory Case Study Based on BBOB
ER -
TY - CONF
AB - The Traveling Salesperson Problem (TSP) is one of the best-known combinatorial optimisation problems. However, many real-world problems are composed of several interacting components. The Traveling Thief Problem (TTP) addresses such interactions by combining two combinatorial optimisation problems, namely the TSP and the Knapsack Problem (KP). Recently, a new problem called the node weight dependent Traveling Salesperson Problem (W-TSP) has been introduced where nodes have weights that influence the cost of the tour. In this paper, we compare W-TSP and TTP. We investigate the structure of the optimised tours for W-TSP and TTP and the impact of using each others fitness function. Our experimental results suggest (1) that the W-TSP often can be solved better using the TTP fitness function and (2) final W-TSP and TTP solutions show different distributions when compared with optimal TSP or weighted greedy solutions.
AU - Bossek, Jakob
AU - Neumann, Aneta
AU - Neumann, Frank
ID - 48852
KW - Evolutionary algorithms
KW - Node weight dependent TSP
KW - Traveling Thief Problem
SN - 978-3-030-58111-4
T2 - Parallel Problem Solving from Nature (PPSN XVI)
TI - Optimising Tours for the Weighted Traveling Salesperson Problem and the Traveling Thief Problem: A Structural Comparison of Solutions
ER -
TY - CONF
AB - We consider a dynamic bi-objective vehicle routing problem, where a subset of customers ask for service over time. Therein, the distance traveled by a single vehicle and the number of unserved dynamic requests is minimized by a dynamic evolutionary multi-objective algorithm (DEMOA), which operates on discrete time windows (eras). A decision is made at each era by a decision-maker, thus any decision depends on irreversible decisions made in foregoing eras. To understand effects of sequences of decision-making and interactions/dependencies between decisions made, we conduct a series of experiments. More precisely, we fix a set of decision-maker preferences D and the number of eras n{$<$}inf{$>$}t{$<$}/inf{$>$} and analyze all $|D|\^{n_t}$ combinations of decision-maker options. We find that for random uniform instances (a) the final selected solutions mainly depend on the final decision and not on the decision history, (b) solutions are quite robust with respect to the number of unvisited dynamic customers, and (c) solutions of the dynamic approach can even dominate solutions obtained by a clairvoyant EMOA. In contrast, for instances with clustered customers, we observe a strong dependency on decision-making history as well as more variance in solution diversity.
AU - Bossek, Jakob
AU - Grimme, Christian
AU - Rudolph, Günter
AU - Trautmann, Heike
ID - 48846
T2 - 2020 IEEE Congress on Evolutionary Computation (CEC)
TI - Towards Decision Support in Dynamic Bi-Objective Vehicle Routing
ER -
TY - CONF
AB - Evolving diverse sets of high quality solutions has gained increasing interest in the evolutionary computation literature in recent years. With this paper, we contribute to this area of research by examining evolutionary diversity optimisation approaches for the classical Traveling Salesperson Problem (TSP). We study the impact of using different diversity measures for a given set of tours and the ability of evolutionary algorithms to obtain a diverse set of high quality solutions when adopting these measures. Our studies show that a large variety of diverse high quality tours can be achieved by using our approaches. Furthermore, we compare our approaches in terms of theoretical properties and the final set of tours obtained by the evolutionary diversity optimisation algorithm.
AU - Do, Anh Viet
AU - Bossek, Jakob
AU - Neumann, Aneta
AU - Neumann, Frank
ID - 48879
KW - diversity maximisation
KW - evolutionary algorithms
KW - travelling salesperson problem
SN - 978-1-4503-7128-5
T2 - Proceedings of the Genetic and Evolutionary Computation Conference
TI - Evolving Diverse Sets of Tours for the Travelling Salesperson Problem
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TY - CONF
AB - Evolutionary algorithms (EAs) are general-purpose problem solvers that usually perform an unbiased search. This is reasonable and desirable in a black-box scenario. For combinatorial optimization problems, often more knowledge about the structure of optimal solutions is given, which can be leveraged by means of biased search operators. We consider the Minimum Spanning Tree (MST) problem in a single- and multi-objective version, and introduce a biased mutation, which puts more emphasis on the selection of edges of low rank in terms of low domination number. We present example graphs where the biased mutation can significantly speed up the expected runtime until (Pareto-)optimal solutions are found. On the other hand, we demonstrate that bias can lead to exponential runtime if "heavy" edges are necessarily part of an optimal solution. However, on general graphs in the single-objective setting, we show that a combined mutation operator which decides for unbiased or biased edge selection in each step with equal probability exhibits a polynomial upper bound - as unbiased mutation - in the worst case and benefits from bias if the circumstances are favorable.
AU - Roostapour, Vahid
AU - Bossek, Jakob
AU - Neumann, Frank
ID - 48895
KW - biased mutation
KW - evolutionary algorithms
KW - minimum spanning tree problem
KW - runtime analysis
SN - 978-1-4503-7128-5
T2 - Proceedings of the 2020 Genetic and Evolutionary Computation Conference
TI - Runtime Analysis of Evolutionary Algorithms with Biased Mutation for the Multi-Objective Minimum Spanning Tree Problem
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TY - CONF
AB - In this work we focus on the well-known Euclidean Traveling Salesperson Problem (TSP) and two highly competitive inexact heuristic TSP solvers, EAX and LKH, in the context of per-instance algorithm selection (AS). We evolve instances with nodes where the solvers show strongly different performance profiles. These instances serve as a basis for an exploratory study on the identification of well-discriminating problem characteristics (features). Our results in a nutshell: we show that even though (1) promising features exist, (2) these are in line with previous results from the literature, and (3) models trained with these features are more accurate than models adopting sophisticated feature selection methods, the advantage is not close to the virtual best solver in terms of penalized average runtime and so is the performance gain over the single best solver. However, we show that a feature-free deep neural network based approach solely based on visual representation of the instances already matches classical AS model results and thus shows huge potential for future studies.
AU - Seiler, Moritz
AU - Pohl, Janina
AU - Bossek, Jakob
AU - Kerschke, Pascal
AU - Trautmann, Heike
ID - 48897
KW - Automated algorithm selection
KW - Deep learning
KW - Feature-based approaches
KW - Traveling Salesperson Problem
SN - 978-3-030-58111-4
T2 - Parallel Problem Solving from {Nature} (PPSN XVI)
TI - Deep Learning as a Competitive Feature-Free Approach for Automated Algorithm Selection on the Traveling Salesperson Problem
ER -