@article{RebolledoRehbachEibenetal.,
  author    = {Rebolledo, Margarita and Rehbach, Frederik and Eiben, A.E. and Bartz-Beielstein, Thomas},
  title     = {Parallelized Bayesian Optimization for Problems with Expensive Evaluation Functions},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-9078},
  pages     = {2},
  abstract  = {Many black-box optimization problems rely on simulations to evaluate the quality of candidate solutions. These evaluations can be computationally expensive and very time-consuming. We present and approach to mitigate this problem by taking into consideration two factors: The number of evaluations and the execution time. We aim to keep the number of evaluations low by using Bayesian optimization (BO) - known to be sample efficient- and to reduce wall-clock times by executing parallel evaluations. Four parallelization methods using BO as optimizer are compared against the inherently parallel CMA-ES. Each method is evaluated on all the 24 objective functions of the Black-Box-Optimization-Benchmarking test suite in their 20-dimensional versions. The results show that parallelized BO outperforms the state-of-the-art CMA-ES on most of the test functions, also on higher dimensions.},
  subject      = {Optimierung},
  language  = {en}
}
@techreport{RebolledoRehbachEibenetal.,
  type      = {Working Paper},
  author    = {Rebolledo, Margarita and Rehbach, Frederik and Eiben, A.E. and Bartz-Beielstein, Thomas},
  title     = {Parallelized Bayesian Optimization for Expensive Robot Controller Evolution},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-9130},
  pages     = {12},
  abstract  = {An important class of black-box optimization problems relies on using simulations to assess the quality of a given candidate solution. Solving such problems can be computationally expensive because each simulation is very time-consuming. We present an approach to mitigate this problem by distinguishing two factors of computational cost: the number of trials and the time needed to execute the trials. Our approach tries to keep down the number of trials by using Bayesian optimization (BO) -known to be sample efficient- and reducing wall-clock times by parallel execution of trials. We compare the performance of four parallelization methods and two model-free alternatives. Each method is evaluated on all 24 objective functions of the Black-Box-Optimization- Benchmarking (BBOB) test suite in their five, ten, and 20-dimensional versions. Additionally, their performance is investigated on six test cases in robot learning. The results show that parallelized BO outperforms the state-of-the-art CMA-ES on the BBOB test functions, especially for higher dimensions. On the robot learning tasks, the differences are less clear, but the data do support parallelized BO as the 'best guess', winning on some cases and never losing.},
  subject      = {Optimierung},
  language  = {en}
}
@article{RehbachZaeffererNaujoksetal.,
  author    = {Rehbach, Frederik and Zaefferer, Martin and Naujoks, Boris and Bartz-Beielstein, Thomas},
  title     = {Expected Improvement versus Predicted Value in Surrogate-Based Optimization},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-9055},
  abstract  = {Surrogate-based optimization relies on so-called infill criteria (acquisition functions) to decide which point to evaluate next. When Kriging is used as the surrogate model of choice (also called Bayesian optimization), one of the most frequently chosen criteria is expected improvement. We argue that the popularity of expected improvement largely relies on its theoretical properties rather than empirically validated performance. Few results from the literature show evidence, that under certain conditions, expected improvement may perform worse than something as simple as the predicted value of the surrogate model. We benchmark both infill criteria in an extensive empirical study on the 'BBOB' function set. This investigation includes a detailed study of the impact of problem dimensionality on algorithm performance. The results support the hypothesis that exploration loses importance with increasing problem dimensionality. A statistical analysis reveals that the purely exploitative search with the predicted value criterion performs better on most problems of five or higher dimensions. Possible reasons for these results are discussed. In addition, we give an in-depth guide for choosing the infill criteria based on prior knowledge about the problem at hand, its dimensionality, and the available budget.},
  language  = {en}
}
@article{RehbachGentileBartzBeielstein,
  author    = {Rehbach, Frederik and Gentile, Lorenzo and Bartz-Beielstein, Thomas},
  title     = {Variable Reduction for Surrogate-Based Optimization},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-9068},
  abstract  = {Real-world problems such as computational fluid dynamics simulations and finite element analyses are computationally expensive. A standard approach to mitigating the high computational expense is Surrogate-Based Optimization (SBO). Yet, due to the high-dimensionality of many simulation problems, SBO is not directly applicable or not efficient. Reducing the dimensionality of the search space is one method to overcome this limitation. In addition to the applicability of SBO, dimensionality reduction enables easier data handling and improved data and model interpretability. Regularization is considered as one state-of-the-art technique for dimensionality reduction. We propose a hybridization approach called Regularized-Surrogate-Optimization (RSO) aimed at overcoming difficulties related to high-dimensionality. It couples standard Kriging-based SBO with regularization techniques. The employed regularization methods are based on three adaptations of the least absolute shrinkage and selection operator (LASSO). In addition, tree-based methods are analyzed as an alternative variable selection method. An extensive study is performed on a set of artificial test functions and two real-world applications: the electrostatic precipitator problem and a multilayered composite design problem. Experiments reveal that RSO requires significantly less time than standard SBO to obtain comparable results. The pros and cons of the RSO approach are discussed, and recommendations for practitioners are presented.},
  language  = {en}
}
@article{RehbachGentileBartzBeielstein,
  author    = {Rehbach, Frederik and Gentile, Lorenzo and Bartz-Beielstein, Thomas},
  title     = {Feature Selection for Surrogate Model-Based Optimization},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-9044},
  abstract  = {We propose a hybridization approach called Regularized-Surrogate- Optimization (RSO) aimed at overcoming difficulties related to high- dimensionality. It combines standard Kriging-based SMBO with regularization techniques. The employed regularization methods use the least absolute shrinkage and selection operator (LASSO). An extensive study is performed on a set of artificial test functions and two real-world applications: the electrostatic precipitator problem and a multilayered composite design problem. Experiments reveal that RSO requires significantly less time than Kriging to obtain comparable results. The pros and cons of the RSO approach are discussed and recommendations for practitioners are presented.},
  language  = {en}
}
@techreport{BartzBeielsteinDoerrBosseketal.,
  type      = {Working Paper},
  author    = {Bartz-Beielstein, Thomas and Doerr, Carola and Bossek, Jakob and Chandrasekaran, Sowmya and Eftimov, Tome and Fischbach, Andreas and Kerschke, Pascal and Lopez-Ibanez, Manuel and Malan, Katherine M. and Moore, Jason H. and Naujoks, Boris and Orzechowski, Patryk and Volz, Vanessa and Wagner, Markus and Weise, Thomas},
  title     = {Benchmarking in Optimization: Best Practice and Open Issues},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-9022},
  pages     = {58},
  abstract  = {This survey compiles ideas and recommendations from more than a dozen researchers with different backgrounds and from different institutes around the world. Promoting best practice in benchmarking is its main goal. The article discusses eight essential topics in benchmarking: clearly stated goals, well- specified problems, suitable algorithms, adequate performance measures, thoughtful analysis, effective and efficient designs, comprehensible presentations, and guaranteed reproducibility. The final goal is to provide well-accepted guidelines (rules) that might be useful for authors and reviewers. As benchmarking in optimization is an active and evolving field of research this manuscript is meant to co-evolve over time by means of periodic updates.},
  subject      = {Optimierung},
  language  = {en}
}
@inproceedings{VoellerSchmidtMuellerPeters,
  author    = {V{\"o}ller, Michaele and Schmidt, Jan-Philipp and M{\"u}ller-Peters, Horst},
  title     = {Revolutionieren Big Data und KI die Versicherungswirtschaft? 24. K{\"o}lner Versicherungssymposium am 14. November 2019},
  issn      = {2192-8479},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-8996},
  pages     = {68},
  abstract  = {Die Frage, ob Big Data und K{\"u}nstliche Intelligenz (KI) die Versicherungswirtschaft revolutionieren, besch{\"a}ftigt schon seit einiger Zeit unsere Gesellschaft sowie im Besonderen die Versicherungsbranche. Die Fortschritte in j{\"u}ngster Vergangenheit in der KI und bei der Auswertung großer Datenmengen sowie die große mediale Aufmerksamkeit sind immens. Somit waren Big Data und K{\"u}nstliche Intelligenz auch die diesj{\"a}hrigen vielversprechenden Themen des 24. K{\"o}lner Versicherungs- symposiums der TH K{\"o}ln am 14. November 2019: Das ivwK{\"o}ln hatte zum fachlichen Austausch eingeladen, ein attraktives Vortragsprogramm zusammengestellt und Networking-Gelegenheiten f{\"u}r die G{\"a}ste aus Forschung und Praxis vorbereitet. Der vorliegende Proceedings-Band umfasst die Vortragsinhalte der verschiedenen Referenten.},
  subject      = {Versicherungswirtschaft},
  language  = {de}
}
@book{OPUS4-894,
  title     = {Das ehemalige Sendegeb{\"a}ude in K{\"o}ln-Raderthal. Erhaltung und Nutzung.},
  editor    = {Sch{\"o}ndeling, Norbert},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-8947},
  pages     = {283},
  abstract  = {K{\"o}lner Beitr{\"a}ge zur Baugeschichte und Denkmalpflege, Band 1. Das ehemalige Sendegeb{\"a}ude in K{\"o}ln-Raderthal. Erhaltung und Nutzung. Norbert Sch{\"o}ndeling (Hrsg.)},
  subject      = {Architektur},
  language  = {de}
}
@techreport{GatzertMuellerPeters,
  type      = {Working Paper},
  author    = {Gatzert, Nadine and M{\"u}ller-Peters, Horst},
  title     = {Todsicher: Die Wahrnehmung und Fehlwahrnehmung von Alltagsrisiken in der {\"O}ffentlichkeit},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-8923},
  pages     = {99},
  abstract  = {Die Risikowahrnehmung von B{\"u}rgern und Verbrauchern weicht aufgrund von psychologischen Verzerrungseffekten in vielen F{\"a}llen deutlich von den realen Risiken ab, was zu „irrationalen" Entscheidungen und ungeeignetem Vorsorgen und Versichern f{\"u}hren kann. Ziel der Studie ist es, solche Abweichungen in der Wahrnehmung von allt{\"a}glichen Risiken in der deutschen Bev{\"o}lkerung aufzuzeigen. Im Wege einer empirischen Untersuchung wurde daher repr{\"a}sentativ erhoben, wie unterschiedliche Risiken aus den drei Lebensbereichen „Auto und Mobilit{\"a}t", „Eigentum, Beruf und Familie" sowie „Gesundheit und Leben" in der Bev{\"o}lkerung eingesch{\"a}tzt werden. Der subjektiven Risikowahrnehmung werden dann die entsprechenden statistischen Eintrittswahrscheinlichkeiten gegen{\"u}ber gestellt. Im Ergebnis zeigt sich, dass die Wahrscheinlichkeit seltener Ereignissemeist {\"u}bersch{\"a}tzt wird. Das gilt wiederum insbesondere f{\"u}r „medienwirksame" Ereignisse wie t{\"o}dliche Verkehrsunf{\"a}lle oder die Gefahr durch Terroranschl{\"a}ge. H{\"a}ufigere Ereignisse werden dagegen eher untersch{\"a}tzt. Neben Sachsch{\"a}den oder Eigentumsdelikten gilt dies insbesondere f{\"u}r Brand-und Leitungswassersch{\"a}den. Besonders auff{\"a}llig ist zudem die Untersch{\"a}tzung der H{\"a}ufigkeit von Rechtsf{\"a}llen. Bezogen auf die eigene Person im Vergleich zur Betroffenheit in der Bev{\"o}lkerung, werden Terrorgefahren, t{\"o}dliche Verkehrsunf{\"a}lle und Computerkriminalit{\"a}t als besonders hoch eingesch{\"a}tzt. Kontakt mit dem Gesetz -sei es ein Verlust der Fahrerlaubnis, einer Straftat verd{\"a}chtigt zu werden oder in einen zivilen Rechtsstreit verwickelt zu werden, betrifft hingegen eher die Bev{\"o}lkerung allgemein und damit „die Anderen". Auch Erfahrungen im pers{\"o}nlichen Umfeld spielen eine wichtige Rolle, indem die eigene Gef{\"a}hrdung als deutlich h{\"o}her eingesch{\"a}tzt wird. Das gilt in besonderem Maße f{\"u}r Ereignisse, die ansonsten als sehr unwahrscheinlich angesehen werden (z.B. t{\"o}dlicher Flugzeugunfall, t{\"o}dliches Gewaltverbrechen, Straftatverdacht), aber auch f{\"u}r Berufsunf{\"a}higkeits-sowie Krankheitsrisiken.},
  subject      = {Risiko},
  language  = {de}
}
@book{FeketeHetkaemperNorf,
  author    = {Fekete, Alexander and Hetk{\"a}mper, Chris and Norf, Celia},
  title     = {Bev{\"o}lkerungsschutz im gesellschaftlichen Wandel (BigWa)},
  editor    = {Fehn, Karsten and Fekete, Alexander and Hetk{\"a}mper, Chris and Lechleuthner, Alexander and Norf, Celia and Mudimu, Ompe Aim{\´e} and Schremmer, Ulf},
  url       = {http://nbn-resolving.de/urn:nbn:de:hbz:832-cos4-8885},
  pages     = {45},
  abstract  = {Mit dem Forschungsschwerpunkt „Bev{\"o}lkerungsschutz im gesellschaftlichen Wandel" (BigWa) untersuchten an der Technischen K{\"o}ln verschiedene Fachbereiche in den vergangenen Jahren interdisziplin{\"a}r die Auswirkungen des Wandels der Gesellschaftsstruktur (z.B. h{\"o}heres Durchschnittslebensalter, R{\"u}ckgang der Geburtenrate) auf den Bev{\"o}lkerungsschutz. Weniger Menschen engagieren sich ehrenamtlich in Hilfsorganisationen und zugleich stellen sich Beh{\"o}rden und Organisationen mit Sicherheitsaufgaben durch neue Gefahrenereignisse weitere Herausforderungen. Mit diesem Band werden auszugsweise im Rahmen des Forschungsschwerpunkts erfolgte Arbeiten, gewonnene Erkenntnisse und Ergebnisse dargestellt sowie verschiedene betreute Abschlussarbeiten vorgestellt.},
  subject      = {Katastrophenschutz},
  language  = {de}
}