TY - GEN A1 - Pilz, Marco A1 - Cotton, Fabrice Pierre A1 - Razafindrakoto, Hoby Njara Tendrisoa A1 - Weatherill, Graeme A1 - Spies, Thomas T1 - Regional broad-band ground-shaking modelling over extended and thick sedimentary basins BT - An example from the Lower Rhine Embayment (Germany) T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The simulation of broad-band (0.1 to 10 + Hz) ground-shaking over deep and spatially extended sedimentary basins at regional scales is challenging. We evaluate the ground-shaking of a potential M 6.5 earthquake in the southern Lower Rhine Embayment, one of the most important areas of earthquake recurrence north of the Alps, close to the city of Cologne in Germany. In a first step, information from geological investigations, seismic experiments and boreholes is combined for deriving a harmonized 3D velocity and attenuation model of the sedimentary layers. Three alternative approaches are then applied and compared to evaluate the impact of the sedimentary cover on ground-motion amplification. The first approach builds on existing response spectra ground-motion models whose amplification factors empirically take into account the influence of the sedimentary layers through a standard parameterization. In the second approach, site-specific 1D amplification functions are computed from the 3D basin model. Using a random vibration theory approach, we adjust the empirical response spectra predicted for soft rock conditions by local site amplification factors: amplifications and associated ground-motions are predicted both in the Fourier and in the response spectra domain. In the third approach, hybrid physics-based ground-motion simulations are used to predict time histories for soft rock conditions which are subsequently modified using the 1D site-specific amplification functions computed in method 2. For large distances and at short periods, the differences between the three approaches become less notable due to the significant attenuation of the sedimentary layers. At intermediate and long periods, generic empirical ground-motion models provide lower levels of amplification from sedimentary soils compared to methods taking into account site-specific 1D amplification functions. In the near-source region, hybrid physics-based ground-motions models illustrate the potentially large variability of ground-motion due to finite source effects. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1371 KW - ground-motion modelling KW - site effects KW - scenario KW - random vibration KW - theory KW - hybrid modelling Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-571655 SN - 1866-8372 IS - 2 ER - TY - JOUR A1 - Doerr, Benjamin A1 - Kötzing, Timo A1 - Lagodzinski, Gregor J. A. A1 - Lengler, Johannes T1 - The impact of lexicographic parsimony pressure for ORDER/MAJORITY on the run time JF - Theoretical computer science : the journal of the EATCS N2 - While many optimization problems work with a fixed number of decision variables and thus a fixed-length representation of possible solutions, genetic programming (GP) works on variable-length representations. A naturally occurring problem is that of bloat, that is, the unnecessary growth of solution lengths, which may slow down the optimization process. So far, the mathematical runtime analysis could not deal well with bloat and required explicit assumptions limiting bloat. In this paper, we provide the first mathematical runtime analysis of a GP algorithm that does not require any assumptions on the bloat. Previous performance guarantees were only proven conditionally for runs in which no strong bloat occurs. Together with improved analyses for the case with bloat restrictions our results show that such assumptions on the bloat are not necessary and that the algorithm is efficient without explicit bloat control mechanism. More specifically, we analyzed the performance of the (1 + 1) GP on the two benchmark functions ORDER and MAJORITY. When using lexicographic parsimony pressure as bloat control, we show a tight runtime estimate of O(T-init + nlogn) iterations both for ORDER and MAJORITY. For the case without bloat control, the bounds O(T-init logT(i)(nit) + n(logn)(3)) and Omega(T-init + nlogn) (and Omega(T-init log T-init) for n = 1) hold for MAJORITY(1). KW - genetic programming KW - bloat control KW - theory KW - runtime analysis Y1 - 2020 U6 - https://doi.org/10.1016/j.tcs.2020.01.011 SN - 0304-3975 SN - 1879-2294 VL - 816 SP - 144 EP - 168 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Doerr, Benjamin A1 - Krejca, Martin S. T1 - Significance-based estimation-of-distribution algorithms JF - IEEE transactions on evolutionary computation N2 - Estimation-of-distribution algorithms (EDAs) are randomized search heuristics that create a probabilistic model of the solution space, which is updated iteratively, based on the quality of the solutions sampled according to the model. As previous works show, this iteration-based perspective can lead to erratic updates of the model, in particular, to bit-frequencies approaching a random boundary value. In order to overcome this problem, we propose a new EDA based on the classic compact genetic algorithm (cGA) that takes into account a longer history of samples and updates its model only with respect to information which it classifies as statistically significant. We prove that this significance-based cGA (sig-cGA) optimizes the commonly regarded benchmark functions OneMax (OM), LeadingOnes, and BinVal all in quasilinear time, a result shown for no other EDA or evolutionary algorithm so far. For the recently proposed stable compact genetic algorithm-an EDA that tries to prevent erratic model updates by imposing a bias to the uniformly distributed model-we prove that it optimizes OM only in a time exponential in its hypothetical population size. Similarly, we show that the convex search algorithm cannot optimize OM in polynomial time. KW - heuristic algorithms KW - sociology KW - statistics KW - history KW - probabilistic KW - logic KW - benchmark testing KW - genetic algorithms KW - estimation-of-distribution KW - algorithm (EDA) KW - run time analysis KW - theory Y1 - 2020 U6 - https://doi.org/10.1109/TEVC.2019.2956633 SN - 1089-778X SN - 1941-0026 VL - 24 IS - 6 SP - 1025 EP - 1034 PB - Institute of Electrical and Electronics Engineers CY - New York, NY ER - TY - JOUR A1 - Kötzing, Timo A1 - Lagodzinski, Gregor J. A. A1 - Lengler, Johannes A1 - Melnichenko, Anna T1 - Destructiveness of lexicographic parsimony pressure and alleviation by a concatenation crossover in genetic programming JF - Theoretical computer science N2 - For theoretical analyses there are two specifics distinguishing GP from many other areas of evolutionary computation: the variable size representations, in particular yielding a possible bloat (i.e. the growth of individuals with redundant parts); and also the role and the realization of crossover, which is particularly central in GP due to the tree-based representation. Whereas some theoretical work on GP has studied the effects of bloat, crossover had surprisingly little share in this work.
We analyze a simple crossover operator in combination with randomized local search, where a preference for small solutions minimizes bloat (lexicographic parsimony pressure); we denote the resulting algorithm Concatenation Crossover GP. We consider three variants of the well-studied MAJORITY test function, adding large plateaus in different ways to the fitness landscape and thus giving a test bed for analyzing the interplay of variation operators and bloat control mechanisms in a setting with local optima. We show that the Concatenation Crossover GP can efficiently optimize these test functions, while local search cannot be efficient for all three variants independent of employing bloat control. (C) 2019 Elsevier B.V. All rights reserved. KW - genetic programming KW - mutation KW - theory KW - run time analysis Y1 - 2020 U6 - https://doi.org/10.1016/j.tcs.2019.11.036 SN - 0304-3975 VL - 816 SP - 96 EP - 113 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lazarides, Rebecca A1 - Raufelder, Diana T1 - Control-value theory in the context of teaching BT - does teaching quality moderate relations between academic self-concept and achievement emotions? JF - British journal of educational psychology N2 - Background: Students' self-concept of ability is an important predictor of their achievement emotions. However, little is known about how learning environments affect these interrelations. Aims: Referring to Pekrun's control-value theory, this study investigated whether teacher-reported teaching quality at the classroom level would moderate the relation between student-level mathematics self-concept at the beginning of the school year and students' achievement emotions at the middle of the school year. Sample: Data of 807 ninth and tenth graders (53.4% girls) and their mathematics teachers (58.1% male) were analysed. Method: Students and teachers completed questionnaires at the beginning of the school year and at the middle of the school year. Multi-level modelling and cross-level interaction analyses were used to examine the longitudinal relations between self-concept, teacher-perceived teaching quality, and achievement emotions as well as potential interaction effects. Results: Mathematics self-concept significantly and positively related to enjoyment in mathematics and negatively related to anxiety. Teacher-reported structuredness decreased students' anxiety. Mathematics self-concept only had a significant and positive effect on students' enjoyment at high levels of teacher-reported cognitive activation and at high levels of structuredness. Conclusions: High teaching quality can be seen as a resource that strengthens the positive relations between academic self-concept and positive achievement emotions. KW - achievement emotions KW - teaching quality KW - self-concept KW - control-value KW - theory Y1 - 2020 U6 - https://doi.org/10.1111/bjep.12352 SN - 0007-0998 SN - 2044-8279 VL - 91 IS - 1 SP - 127 EP - 147 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Pilz, Marco A1 - Cotton, Fabrice Pierre A1 - Razafindrakoto, Hoby Njara Tendrisoa A1 - Weatherill, Graeme A1 - Spies, Thomas T1 - Regional broad-band ground-shaking modelling over extended and thick sedimentary basins BT - An example from the Lower Rhine Embayment (Germany) JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - The simulation of broad-band (0.1 to 10 + Hz) ground-shaking over deep and spatially extended sedimentary basins at regional scales is challenging. We evaluate the ground-shaking of a potential M 6.5 earthquake in the southern Lower Rhine Embayment, one of the most important areas of earthquake recurrence north of the Alps, close to the city of Cologne in Germany. In a first step, information from geological investigations, seismic experiments and boreholes is combined for deriving a harmonized 3D velocity and attenuation model of the sedimentary layers. Three alternative approaches are then applied and compared to evaluate the impact of the sedimentary cover on ground-motion amplification. The first approach builds on existing response spectra ground-motion models whose amplification factors empirically take into account the influence of the sedimentary layers through a standard parameterization. In the second approach, site-specific 1D amplification functions are computed from the 3D basin model. Using a random vibration theory approach, we adjust the empirical response spectra predicted for soft rock conditions by local site amplification factors: amplifications and associated ground-motions are predicted both in the Fourier and in the response spectra domain. In the third approach, hybrid physics-based ground-motion simulations are used to predict time histories for soft rock conditions which are subsequently modified using the 1D site-specific amplification functions computed in method 2. For large distances and at short periods, the differences between the three approaches become less notable due to the significant attenuation of the sedimentary layers. At intermediate and long periods, generic empirical ground-motion models provide lower levels of amplification from sedimentary soils compared to methods taking into account site-specific 1D amplification functions. In the near-source region, hybrid physics-based ground-motions models illustrate the potentially large variability of ground-motion due to finite source effects. KW - ground-motion modelling KW - site effects KW - scenario KW - random vibration KW - theory KW - hybrid modelling Y1 - 2020 U6 - https://doi.org/10.1007/s10518-020-01004-w SN - 1570-761X SN - 1573-1456 VL - 19 IS - 2 SP - 581 EP - 603 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Denecke, Klaus-Dieter T1 - Partial clones JF - Asian-European journal of mathematics : AEJM N2 - A set C of operations defined on a nonempty set A is said to be a clone if C is closed under composition of operations and contains all projection mappings. The concept of a clone belongs to the algebraic main concepts and has important applications in Computer Science. A clone can also be regarded as a many-sorted algebra where the sorts are the n-ary operations defined on set A for all natural numbers n >= 1 and the operations are the so-called superposition operations S-m(n) for natural numbers m, n >= 1 and the projection operations as nullary operations. Clones generalize monoids of transformations defined on set A and satisfy three clone axioms. The most important axiom is the superassociative law, a generalization of the associative law. If the superposition operations are partial, i.e. not everywhere defined, instead of the many-sorted clone algebra, one obtains partial many-sorted algebras, the partial clones. Linear terms, linear tree languages or linear formulas form partial clones. In this paper, we give a survey on partial clones and their properties. KW - Operation KW - term KW - formula KW - superposition of operations KW - terms and KW - formulas KW - linear term KW - linear formula KW - linear tree language KW - clone KW - partial clone KW - linear hypersubstitution KW - dht-symmetric category KW - partial KW - theory Y1 - 2020 U6 - https://doi.org/10.1142/S1793557120501612 SN - 1793-5571 SN - 1793-7183 VL - 13 IS - 8 PB - World Scientific CY - Singapore ER -