@article{16294, abstract = {{Model predictive control is a prominent approach to construct a feedback control loop for dynamical systems. Due to real-time constraints, the major challenge in MPC is to solve model-based optimal control problems in a very short amount of time. For linear-quadratic problems, Bemporad et al. have proposed an explicit formulation where the underlying optimization problems are solved a priori in an offline phase. In this article, we present an extension of this concept in two significant ways. We consider nonlinear problems and - more importantly - problems with multiple conflicting objective functions. In the offline phase, we build a library of Pareto optimal solutions from which we then obtain a valid compromise solution in the online phase according to a decision maker's preference. Since the standard multi-parametric programming approach is no longer valid in this situation, we instead use interpolation between different entries of the library. To reduce the number of problems that have to be solved in the offline phase, we exploit symmetries in the dynamical system and the corresponding multiobjective optimal control problem. The results are verified using two different examples from autonomous driving.}}, author = {{Ober-Blöbaum, Sina and Peitz, Sebastian}}, journal = {{International Journal of Robust and Nonlinear Control}}, pages = {{380--403}}, title = {{{Explicit multiobjective model predictive control for nonlinear systems with symmetries}}}, doi = {{10.1002/rnc.5281}}, volume = {{31(2)}}, year = {{2021}}, } @article{24140, author = {{Ramaswamy, Arunselvan and Redder, Adrian and Quevedo, Daniel E.}}, journal = {{IEEE Transactions on Automatic Control}}, pages = {{1--1}}, title = {{{Distributed optimization over time-varying networks with stochastic information delays}}}, doi = {{10.1109/TAC.2021.3108492}}, year = {{2021}}, } @inproceedings{21726, author = {{Triebus, Marcel and Tröster, Thomas}}, booktitle = {{9th NRW Nano Conference - Innovations in Materials and Applications}}, location = {{Web}}, title = {{{HyOpt - Optimization-Based Development of Hybrid Materials}}}, year = {{2021}}, } @article{33008, author = {{Ludwig-Walz, Helena and Nyasordzi, Juliana and Weber, Katharina S. and Buyken, Anette and Kroke, Anja}}, issn = {{0939-4753}}, journal = {{Nutrition, Metabolism and Cardiovascular Diseases}}, keywords = {{Cardiology and Cardiovascular Medicine, Nutrition and Dietetics, Endocrinology, Diabetes and Metabolism, Medicine (miscellaneous)}}, number = {{4}}, pages = {{833--852}}, publisher = {{Elsevier BV}}, title = {{{Maternal pregnancy weight or gestational weight gain and offspring's blood pressure: A systematic review}}}, doi = {{10.1016/j.numecd.2021.11.011}}, volume = {{32}}, year = {{2021}}, } @article{27575, abstract = {{There is a distinct increase in the prevalence of depression with the onset of puberty. The role of peripubertal testosterone levels in boys in this context is insufficiently understood and may be modulated by a functional polymorphism of the androgen receptor gene (AR), a variable number of CAG repeats. Moreover, there is preliminary evidence that the relationship between testosterone, CAG repeat length, and the severity of depressive symptoms may differ between subclinical and overt depression, but this has neither been studied in a clinical sample of adolescents with depression nor compared between subclinical and overt depression in an adequately powered study. To investigate the relationship between free testosterone, CAG repeat length of the AR, depression status (subclinical vs. overt), and the severity of depressive symptoms, 118 boys treated as in- or daycare patients at a single psychiatric hospital were studied. Of these, 73 boys had at least mild depressive symptoms according to the Beck Depression Inventory-II (BDI-II &gt; 13). Higher-order moderation analysis in the multiple regression framework revealed a constant relationship between free testosterone and depression severity irrespective of the number of CAG repeats in adolescents with a BDI-II score ≤ 13. In adolescents with a BDI-II score &gt; 13, however, there was a significant negative relationship between free testosterone and BDI-II score in patients with &lt;19 CAG repeats and a significant positive relationship regarding free testosterone and BDI-II score in those with more than 28 CAG repeats, even when considering important covariates. These results suggest that the effects of testosterone on mood in male adolescents with depression depend on the genetic make-up of the AR as well as on depression status. This complex relationship should be considered by future studies addressing mental health issues against an endocrine background and may, moreover, contribute to tailored treatment concepts in psychiatric medicine, especially in adults.}}, author = {{Hirtz, Raphael and Libuda, Lars and Hinney, Anke and Föcker, Manuel and Bühlmeier, Judith and Holterhus, Paul-Martin and Kulle, Alexandra and Kiewert, Cordula and Hebebrand, Johannes and Grasemann, Corinna}}, issn = {{1664-0640}}, journal = {{Frontiers in Psychiatry}}, title = {{{Size Matters: The CAG Repeat Length of the Androgen Receptor Gene, Testosterone, and Male Adolescent Depression Severity}}}, doi = {{10.3389/fpsyt.2021.732759}}, year = {{2021}}, } @article{27571, abstract = {{(1) Background: Evidence has accumulated that patients with anorexia nervosa (AN) are at higher risk for vitamin D deficiency than healthy controls. In epidemiologic studies, low 25(OH) vitamin D (25(OH)D) levels were associated with depression. This study analyzed the relationship between 25(OH)D serum levels in adolescent patients and AN and depressive symptoms over the course of treatment. (2) Methods: 25(OH)D levels and depressive symptoms were analyzed in 93 adolescent (in-)patients with AN from the Anorexia Nervosa Day patient versus Inpatient (ANDI) multicenter trial at clinic admission, discharge, and 1 year follow up. Mixed regression models were used to analyze the relationship between 25(OH)D levels and depressive symptoms assessed by the Beck Depression Inventory (BDI-II). (3) Results: Although mean 25(OH)D levels constantly remained in recommended ranges (≥50 nmol/L) during AN treatment, levels decreased from (in)patient admission to 1 year follow up. Levels of 25(OH)D were neither cross-sectionally, prospectively, nor longitudinally associated with the BDI-II score. (4) Conclusions: This study did not confirm that 25(OH)D levels are associated with depressive symptoms in patients with AN. However, increasing risks of vitamin D deficiency over the course of AN treatment indicate that clinicians should monitor 25(OH)D levels.}}, author = {{Föcker, Manuel and Timmesfeld, Nina and Bühlmeier, Judith and Zwanziger, Denise and Führer, Dagmar and Grasemann, Corinna and Ehrlich, Stefan and Egberts, Karin and Fleischhaker, Christian and Wewetzer, Christoph and Wessing, Ida and Seitz, Jochen and Herpertz-Dahlmann, Beate and Hebebrand, Johannes and Libuda, Lars}}, issn = {{2072-6643}}, journal = {{Nutrients}}, title = {{{Vitamin D Level Trajectories of Adolescent Patients with Anorexia Nervosa at Inpatient Admission, during Treatment, and at One Year Follow Up: Association with Depressive Symptoms}}}, doi = {{10.3390/nu13072356}}, year = {{2021}}, } @article{26632, abstract = {{AbstractAnorexia nervosa (AN) is a severe eating disorder and often associated with altered humoral immune responses. However, distinct B cell maturation stages in peripheral blood in adolescents with AN have not been characterized. Treatment effects and the relationship between clinical and B cell parameters are also not fully understood. Here we investigated the phenotype of circulating B cell subsets and the relationship with body composition in adolescents with AN before (T0, n = 24) and after 6 weeks (T1, n = 20) of treatment. Using multi-parameter flow cytometry, we found increased percentages of antigen-experienced B cells and plasmablasts in patients with AN compared to healthy controls (n = 20). In contrast, percentages of CD1d+CD5+ B cells and transitional B cells with immunoregulatory roles were reduced at T0 and T1. These B cell frequencies correlated positively with fat mass, fat mass index (FMI), free fat mass index, and body mass index standard deviation score. In addition, scavenger-like receptor CD5 expression levels were downregulated on transitional B cells and correlated with fat mass and FMI in AN. Our findings that regulatory B cell subgroups were reduced in AN and their strong relationship with body composition parameters point toward an impact of immunoregulatory B cells in the pathogenesis of AN.}}, author = {{Freff, Jana and Schwarte, Kathrin and Bröker, Lisa and Bühlmeier, Judith and Kraft, Isabelle and Öztürk, Dana and Hinney, Anke and Arolt, Volker and Dannlowski, Udo and Romer, Georg and Baune, Bernhard T. and Hebebrand, Johannes and Föcker, Manuel and Alferink, Judith}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, title = {{{Alterations in B cell subsets correlate with body composition parameters in female adolescents with anorexia nervosa}}}, doi = {{10.1038/s41598-020-80693-4}}, year = {{2021}}, } @article{26525, author = {{Hebebrand, Johannes and Antel, Jochen and Tan, Susanne and Wabitsch, Martin and Wiesing, Urban and Barth, Nikolaus and Ludwig, Christine and Bühlmeier, Judith and Libuda, Lars and Milos, Gabriella and Hinney, Anke}}, issn = {{1422-4917}}, journal = {{Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie}}, pages = {{1--5}}, title = {{{Kurzzeitige Behandlung von Patient_innen mit Anorexia nervosa mit rekombinant hergestelltem Human-Leptin (Metreleptin): Rasch einsetzende positive Effekte auf Stimmung, Kognition und Verhalten}}}, doi = {{10.1024/1422-4917/a000775}}, year = {{2021}}, } @article{30700, author = {{Zirngibl, C. and Dworschak, F. and Schleich, B. and Wartzack, S.}}, journal = {{Production Engineering}}, title = {{{Application of reinforcement learning for the optimization of clinch joint characteristics}}}, doi = {{10.1007/s11740-021-01098-4}}, year = {{2021}}, } @article{30683, abstract = {{When joining lightweight parts of various materials, clinching is a cost efficient solution. In a production line, the quality of a clinch point is primarily controlled by measurement of dimensions, which are accessible from outside. However, methods such as visual testing and measuring the bottom thickness as well as the outer diameter are not able to deliver any information about the most significant geometrical characteristic of the clinch point, neck thickness and undercut. Furthermore, ex-situ destructive methods such as microsectioning cannot detect elastic deformations and cracks that close after unloading. In order to exceed the current limits, a new non-destructive in-situ testing method for the clinching process is necessary. This work proposes a concept to characterize clinch points in-situ by combining two complementary non-destructive methods, namely, computed tomography (CT) and ultrasonic testing. Firstly, clinch points with different geometrical characteristics are analysed experimentally using ex-situ CT to get a highly spatially resolved 3D-image of the object. In this context, highly X-ray attenuating materials enhancing the visibility of the sheet-sheet interface are investigated. Secondly, the test specimens are modelled using finite element method (FEM) and a transient dynamic analysis (TDA) is conducted to study the effect of the geometrical differences on the deformation energy and to qualify the TDA as a fast in-situ non-destructive method for characterizing clinch points at high temporal resolution. }}, author = {{Köhler, D. and Sadeghian, B. and Kupfer, R. and Troschitz, J. and Gude, M. and Brosius, A.}}, journal = {{Key Engineering Materials}}, pages = {{89--96}}, title = {{{A Method for Characterization of Geometric Deviations in Clinch Points with Computed Tomography and Transient Dynamic Analysis}}}, doi = {{10.4028/www.scientific.net/kem.883.89}}, volume = {{883}}, year = {{2021}}, } @article{35303, abstract = {{Abstract Purpose Studies about effects of lunch dietary Glycemic Index (GI) on cognition of schoolchildren are scarce. Our previous CogniDo GI study found no changes of cognition in the early postprandial phase after consumption of two rice types with medium vs. high dietary GI for lunch (i.e., 45 min after starting lunch). This study investigated whether the dietary GI of lunch has an impact on cognition of schoolchildren in the late postprandial phase, 90 min after lunch. Methods A randomized, 2 × 2 crossover intervention study was conducted at a comprehensive school with 5th and 6th grade students. Participants (n = 212) were randomly assigned to either sequence 1 or 2. In the first period, participants of sequence 1 received a dish with high GI rice (GI: 79), those of sequence 2 with medium GI rice (GI: 64)—in the second period, 1 week later, vice versa. Computer-based cognitive testing was performed 90 min after lunch examining tonic alertness, visual search and task switching, and working memory. Treatment effects and treatment effects adjusted for estimated lunch glycemic load (GL) were analyzed using a linear mixed model. Results The selected cognitive parameters were not affected by the GI of lunch 90 min after lunch, neither after intention-to-treat nor in the per-protocol analysis. Adjustment for GL also did not change results. Conclusion The present study revealed no notable differences after the consumption of two rice types with medium vs. high dietary GI for lunch in children’s cognitive function in the late postprandial phase, 90 min after lunch. Clinical trial registration German Clinical Trials Register (DRKS00013597); date of registration: 16/04/2018, retrospectively registered. }}, author = {{Drozdowska, Alina and Sinningen, Kathrin and Falkenstein, Michael and Rudolf, Henrik and Libuda, Lars and Buyken, Anette and Lücke, Thomas and Kersting, Mathilde}}, issn = {{1436-6207}}, journal = {{European Journal of Nutrition}}, keywords = {{Nutrition and Dietetics, Medicine (miscellaneous)}}, number = {{3}}, pages = {{1637--1647}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Impact of lunch with carbohydrates differing in glycemic index on children's cognitive functioning in the late postprandial phase: a randomized crossover study}}}, doi = {{10.1007/s00394-021-02766-y}}, volume = {{61}}, year = {{2021}}, } @inbook{35774, author = {{Albers, Timm and Filipiak, Agnes and Franzen, Katja and Hellmich, Frank}}, booktitle = {{Grenzen. Gänge. Zwischen. Welten. Kontroversen – Entwicklungen – Perspektiven der Inklusionsforschung}}, editor = {{Schimek, Bernhard and Kremsner, Gertraud and Proyer, Michelle and Grubich, Rainer and Paudel, Florentine and Grubich-Müller, Regina}}, pages = {{207–214}}, publisher = {{Verlag Julius Klinkhardt}}, title = {{{Kompetenzentwicklung im inklusiven Unterricht (KinU) – eine internationale Perspektive}}}, doi = {{10.35468/5924-22}}, year = {{2021}}, } @article{36042, author = {{Berger, Thomas}}, journal = {{SIAM Journal on control and Optimization }}, number = {{5}}, pages = {{3203--3230}}, title = {{{Funnel control of the Fokker-Blanck equation for a multidimensional Ornstein-Uhlenbeck process}}}, volume = {{59}}, year = {{2021}}, } @article{46318, abstract = {{Multi-objective (MO) optimization, i.e., the simultaneous optimization of multiple conflicting objectives, is gaining more and more attention in various research areas, such as evolutionary computation, machine learning (e.g., (hyper-)parameter optimization), or logistics (e.g., vehicle routing). Many works in this domain mention the structural problem property of multimodality as a challenge from two classical perspectives: (1) finding all globally optimal solution sets, and (2) avoiding to get trapped in local optima. Interestingly, these streams seem to transfer many traditional concepts of single-objective (SO) optimization into claims, assumptions, or even terminology regarding the MO domain, but mostly neglect the understanding of the structural properties as well as the algorithmic search behavior on a problem’s landscape. However, some recent works counteract this trend, by investigating the fundamentals and characteristics of MO problems using new visualization techniques and gaining surprising insights. Using these visual insights, this work proposes a step towards a unified terminology to capture multimodality and locality in a broader way than it is usually done. This enables us to investigate current research activities in multimodal continuous MO optimization and to highlight new implications and promising research directions for the design of benchmark suites, the discovery of MO landscape features, the development of new MO (or even SO) optimization algorithms, and performance indicators. For all these topics, we provide a review of ideas and methods but also an outlook on future challenges, research potential and perspectives that result from recent developments.}}, author = {{Grimme, Christian and Kerschke, Pascal and Aspar, Pelin and Trautmann, Heike and Preuss, Mike and Deutz, André H. and Wang, Hao and Emmerich, Michael}}, issn = {{0305-0548}}, journal = {{Computers & Operations Research}}, keywords = {{Multimodal optimization, Multi-objective continuous optimization, Landscape analysis, Visualization, Benchmarking, Theory, Algorithms}}, pages = {{105489}}, title = {{{Peeking beyond peaks: Challenges and research potentials of continuous multimodal multi-objective optimization}}}, doi = {{https://doi.org/10.1016/j.cor.2021.105489}}, volume = {{136}}, year = {{2021}}, } @inproceedings{46311, abstract = {{In this work we examine the inner mechanisms of the recently developed sophisticated local search procedure SOMOGSA. This method solves multimodal single-objective continuous optimization problems by first expanding the problem with an additional objective (e.g., a sphere function) to the bi-objective space, and subsequently exploiting local structures and ridges of the resulting landscapes. Our study particularly focusses on the sensitivity of this multiobjectivization approach w.r.t. (i) the parametrization of the artificial second objective, as well as (ii) the position of the initial starting points in the search space. As SOMOGSA is a modular framework for encapsulating local search, we integrate Gradient and Nelder-Mead local search (as optimizers in the respective module) and compare the performance of the resulting hybrid local search to their original single-objective counterparts. We show that the SOMOGSA framework can significantly boost local search by multiobjectivization. Combined with more sophisticated local search and metaheuristics this may help in solving highly multimodal optimization problems in future.}}, author = {{Aspar, Pelin and Kerschke, Pascal and Steinhoff, Vera and Trautmann, Heike and Grimme, Christian}}, booktitle = {{Evolutionary Multi-Criterion Optimization: 11$^th$ International Conference, EMO 2021, Shenzhen, China, March 28–31, 2021, Proceedings}}, editor = {{et al. Ishibuchi, H.}}, pages = {{311–322}}, publisher = {{Springer}}, title = {{{Multi^3: Optimizing Multimodal Single-Objective Continuous Problems in the Multi-Objective Space by Means of Multiobjectivization}}}, doi = {{10.1007/978-3-030-72062-9_25}}, year = {{2021}}, } @inproceedings{21592, abstract = {{We propose a reachability approach for infinite and finite horizon multi-objective optimization problems for low-thrust spacecraft trajectory design. The main advantage of the proposed method is that the Pareto front can be efficiently constructed from the zero level set of the solution to a Hamilton-Jacobi-Bellman equation. We demonstrate the proposed method by applying it to a low-thrust spacecraft trajectory design problem. By deriving the analytic expression for the Hamiltonian and the optimal control policy, we are able to efficiently compute the backward reachable set and reconstruct the optimal trajectories. Furthermore, we show that any reconstructed trajectory will be guaranteed to be weakly Pareto optimal. The proposed method can be used as a benchmark for future research of applying reachability analysis to low-thrust spacecraft trajectory design.}}, author = {{Vertovec, Nikolaus and Ober-Blöbaum, Sina and Margellos, Kostas}}, location = {{Rotterdam, the Netherlands}}, pages = {{1975--1980}}, title = {{{Multi-objective minimum time optimal control for low-thrust trajectory design}}}, year = {{2021}}, } @article{47977, abstract = {{Orange-colored crystals of the oxoferrate tellurate K12+6xFe6Te4−xO27 [x=0.222(4)] were synthesized in a potassium hydroxide hydroflux with a molar water–base ratio n(H2O)/n(KOH) of 1.5 starting from Fe(NO3)3 ⋅ 9H2O, TeO2 and H2O2 at about 200 °C. By using (NH4)2TeO4 instead of TeO2, a fine powder consisting of microcrystalline spheres of K12+6xFe6Te4−xO27 was obtained. K12+6xFe6Te4−xO27 crystallizes in the acentric cubic space group Iurn:x-wiley:09476539:media:chem202102464:chem202102464-math-0001 3d. [FeIIIO5] pyramids share their apical atoms in [Fe2O9] groups and two of their edges with [TeVIO6] octahedra to form an open framework that consists of two loosely connected, but not interpenetrating, chiral networks. The flexibility of the hinged oxometalate network manifests in a piezoelectric response similar to that of LiNbO3.The potassium cations are mobile in channels that run along the <111> directions and cross in cavities acting as nodes. The ion conductivity of cold-pressed pellets of ball-milled K12+6xFe6Te4−xO27 is 2.3×10^(−4) S ⋅ cm^(−1) at room temperature. Magnetization measurements and neutron diffraction indicate antiferromagnetic coupling in the [Fe2O9] groups.}}, author = {{Albrecht, Ralf and Hoelzel, Markus and Beccard, Henrik and Rüsing, Michael and Eng, Lukas and Doert, Thomas and Ruck, Michael}}, issn = {{0947-6539}}, journal = {{Chemistry – A European Journal}}, keywords = {{General Chemistry, Catalysis, Organic Chemistry}}, number = {{57}}, pages = {{14299--14306}}, publisher = {{Wiley}}, title = {{{Potassium Ion Conductivity in the Cubic Labyrinth of a Piezoelectric, Antiferromagnetic Oxoferrate(III) Tellurate(VI)}}}, doi = {{10.1002/chem.202102464}}, volume = {{27}}, year = {{2021}}, } @inproceedings{48853, abstract = {{In practise, it is often desirable to provide the decision-maker with a rich set of diverse solutions of decent quality instead of just a single solution. In this paper we study evolutionary diversity optimization for the knapsack problem (KP). Our goal is to evolve a population of solutions that all have a profit of at least (1 - {$ϵ$}) {$\cdot$} OPT, where OPT is the value of an optimal solution. Furthermore, they should differ in structure with respect to an entropy-based diversity measure. To this end we propose a simple ({$\mu$} + 1)-EA with initial approximate solutions calculated by a well-known FPTAS for the KP. We investigate the effect of different standard mutation operators and introduce biased mutation and crossover which puts strong probability on flipping bits of low and/or high frequency within the population. An experimental study on different instances and settings shows that the proposed mutation operators in most cases perform slightly inferior in the long term, but show strong benefits if the number of function evaluations is severely limited.}}, author = {{Bossek, Jakob and Neumann, Aneta and Neumann, Frank}}, booktitle = {{Proceedings of the Genetic and Evolutionary Computation Conference}}, isbn = {{978-1-4503-8350-9}}, keywords = {{evolutionary algorithms, evolutionary diversity optimization, knapsack problem, tailored operators}}, pages = {{556–564}}, publisher = {{Association for Computing Machinery}}, title = {{{Breeding Diverse Packings for the Knapsack Problem by Means of Diversity-Tailored Evolutionary Algorithms}}}, doi = {{10.1145/3449639.3459364}}, year = {{2021}}, } @inproceedings{48855, abstract = {{Computing sets of high quality solutions has gained increasing interest in recent years. In this paper, we investigate how to obtain sets of optimal solutions for the classical knapsack problem. We present an algorithm to count exactly the number of optima to a zero-one knapsack problem instance. In addition, we show how to efficiently sample uniformly at random from the set of all global optima. In our experimental study, we investigate how the number of optima develops for classical random benchmark instances dependent on their generator parameters. We find that the number of global optima can increase exponentially for practically relevant classes of instances with correlated weights and profits which poses a justification for the considered exact counting problem.}}, author = {{Bossek, Jakob and Neumann, Aneta and Neumann, Frank}}, booktitle = {{Learning and Intelligent Optimization}}, isbn = {{978-3-030-92120-0}}, keywords = {{Dynamic programming, Exact counting, Sampling, Zero-one knapsack problem}}, pages = {{40–54}}, publisher = {{Springer-Verlag}}, title = {{{Exact Counting and~Sampling of Optima for the Knapsack Problem}}}, doi = {{10.1007/978-3-030-92121-7_4}}, year = {{2021}}, } @inproceedings{48860, abstract = {{In the area of evolutionary computation the calculation of diverse sets of high-quality solutions to a given optimization problem has gained momentum in recent years under the term evolutionary diversity optimization. Theoretical insights into the working principles of baseline evolutionary algorithms for diversity optimization are still rare. In this paper we study the well-known Minimum Spanning Tree problem (MST) in the context of diversity optimization where population diversity is measured by the sum of pairwise edge overlaps. Theoretical results provide insights into the fitness landscape of the MST diversity optimization problem pointing out that even for a population of {$\mu$} = 2 fitness plateaus (of constant length) can be reached, but nevertheless diverse sets can be calculated in polynomial time. We supplement our theoretical results with a series of experiments for the unconstrained and constraint case where all solutions need to fulfill a minimal quality threshold. Our results show that a simple ({$\mu$} + 1)-EA can effectively compute a diversified population of spanning trees of high quality.}}, author = {{Bossek, Jakob and Neumann, Frank}}, booktitle = {{Proceedings of the Genetic and Evolutionary Computation Conference}}, isbn = {{978-1-4503-8350-9}}, keywords = {{evolutionary algorithms, evolutionary diversity optimization, minimum spanning tree, runtime analysis}}, pages = {{198–206}}, publisher = {{Association for Computing Machinery}}, title = {{{Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem}}}, doi = {{10.1145/3449639.3459363}}, year = {{2021}}, }