@proceedings{7758, editor = {{Van Gorp, Pieter and Engels, Gregor}}, publisher = {{Springer}}, title = {{{Theory and Practice of Model Transformations - 9th International Conference ICMT 2016, Held as Part of STAF 2016, Vienna, Austria, July 4-5, 2016, Proceedings}}}, volume = {{9765}}, year = {{2016}}, } @article{5762, abstract = {{This paper introduces the problem of communication pattern adaption for a distributed self-adjusting binary search tree. We propose a simple local algorithm that is closely related to the over thirty-year-old idea of splay trees and evaluate its adaption performance in the distributed scenario if different communication patterns are provided. To do so, the process of self-adjustment is modeled similarly to a basic network creation game in which the nodes want to communicate with only a certain subset of all nodes. We show that, in general, the game (i.e., the process of local adjustments) does not converge, and that convergence is related to certain structures of the communication interests, which we call conflicts. We classify conflicts and show that for two communication scenarios in which convergence is guaranteed, the self-adjusting tree performs well. Furthermore, we investigate the different classes of conflicts separately and show that, for a certain class of conflicts, the performance of the tree network is asymptotically as good as the performance for converging instances. However, for the other conflict classes, a distributed self-adjusting binary search tree adapts poorly.}}, author = {{Strothmann, Thim Frederik}}, issn = {{1526-1719}}, journal = {{Journal of Graph Algorithms and Applications}}, number = {{1}}, pages = {{79--100}}, publisher = {{Journal of Graph Algorithms and Applications}}, title = {{{The Impact of Communication Patterns on Distributed Self-Adjusting Binary Search Tree}}}, doi = {{10.7155/jgaa.00385}}, volume = {{20}}, year = {{2016}}, } @article{7054, author = {{Schuster, J and Kim, T Y and Batke, E and Reuter, Dirk and Wieck, A D}}, issn = {{2053-1591}}, journal = {{Materials Research Express}}, number = {{5}}, publisher = {{IOP Publishing}}, title = {{{Electric field distribution and exciton recombination line shape in GaAs}}}, doi = {{10.1088/2053-1591/3/5/056201}}, volume = {{3}}, year = {{2016}}, } @misc{688, author = {{Kutzias, Damian}}, publisher = {{Universität Paderborn}}, title = {{{Friendship Processes in Network Creation Games}}}, year = {{2016}}, } @misc{689, author = {{Schaefer, Johannes Sebastian}}, publisher = {{Universität Paderborn}}, title = {{{Routing Algorithms on Delayed Networks for Disaster Management Support}}}, year = {{2016}}, } @inproceedings{11908, abstract = {{This paper describes automatic speech recognition (ASR) systems developed jointly by RWTH, UPB and FORTH for the 1ch, 2ch and 6ch track of the 4th CHiME Challenge. In the 2ch and 6ch tracks the final system output is obtained by a Confusion Network Combination (CNC) of multiple systems. The Acoustic Model (AM) is a deep neural network based on Bidirectional Long Short-Term Memory (BLSTM) units. The systems differ by front ends and training sets used for the acoustic training. The model for the 1ch track is trained without any preprocessing. For each front end we trained and evaluated individual acoustic models. We compare the ASR performance of different beamforming approaches: a conventional superdirective beamformer [1] and an MVDR beamformer as in [2], where the steering vector is estimated based on [3]. Furthermore we evaluated a BLSTM supported Generalized Eigenvalue beamformer using NN-GEV [4]. The back end is implemented using RWTH?s open-source toolkits RASR [5], RETURNN [6] and rwthlm [7]. We rescore lattices with a Long Short-Term Memory (LSTM) based language model. The overall best results are obtained by a system combination that includes the lattices from the system of UPB?s submission [8]. Our final submission scored second in each of the three tracks of the 4th CHiME Challenge.}}, author = {{Menne, Tobias and Heymann, Jahn and Alexandridis, Anastasios and Irie, Kazuki and Zeyer, Albert and Kitza, Markus and Golik, Pavel and Kulikov, Ilia and Drude, Lukas and Schlüter, Ralf and Ney, Hermann and Haeb-Umbach, Reinhold and Mouchtaris, Athanasios}}, booktitle = {{Computer Speech and Language}}, title = {{{The RWTH/UPB/FORTH System Combination for the 4th CHiME Challenge Evaluation}}}, year = {{2016}}, } @phdthesis{154, author = {{Cord-Landwehr, Andreas}}, isbn = {{978-3-942647-72-4}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts, Paderborn}}, title = {{{Selfish Network Creation - On Variants of Network Creation Games}}}, volume = {{353}}, year = {{2016}}, } @inproceedings{157, abstract = {{Consider a scheduling problem in which a set of jobs with interjob communication, canonically represented by a weighted tree, needs to be scheduled on m parallel processors interconnected by a shared communication channel. In each time step, we may allow any processed job to use a certain capacity of the channel in order to satisfy (parts of) its communication demands to adjacent jobs processed in parallel. The goal is to find a schedule that minimizes the makespan and in which communication demands of all jobs are satisfied.We show that this problem is NP-hard in the strong sense even if the number of processors and the maximum degree of the underlying tree is constant.Consequently, we design and analyze simple approximation algorithms with asymptotic approximation ratio 2-2/m in case of paths and a ratio of 5/2 in case of arbitrary trees.}}, author = {{König, Jürgen and Mäcker, Alexander and Meyer auf der Heide, Friedhelm and Riechers, Sören}}, booktitle = {{Proceedings of the 10th Annual International Conference on Combinatorial Optimization and Applications (COCOA)}}, pages = {{563----577}}, title = {{{Scheduling with Interjob Communication on Parallel Processors}}}, doi = {{10.1007/978-3-319-48749-6_41}}, year = {{2016}}, } @inproceedings{149, abstract = {{In this paper we consider a strategic variant of the online facility location problem. Given is a graph in which each node serves two roles: it is a strategic client stating requests as well as a potential location for a facility. In each time step one client states a request which induces private costs equal to the distance to the closest facility. Before serving, the clients may collectively decide to open new facilities, sharing the corresponding price. Instead of optimizing the global costs, each client acts selfishly. The prices of new facilities vary between nodes and also change over time, but are always bounded by some fixed value α. Both the requests as well as the facility prices are given by an online sequence and are not known in advance.We characterize the optimal strategies of the clients and analyze their overall performance in comparison to a centralized offline solution. If all players optimize their own competitiveness, the global performance of the system is O(√α⋅α) times worse than the offline optimum. A restriction to a natural subclass of strategies improves this result to O(α). We also show that for fixed facility costs, we can find strategies such that this bound further improves to O(√α).}}, author = {{Drees, Maximilian and Feldkord, Björn and Skopalik, Alexander}}, booktitle = {{Proceedings of the 10th Annual International Conference on Combinatorial Optimization and Applications (COCOA)}}, pages = {{593----607}}, title = {{{Strategic Online Facility Location}}}, doi = {{10.1007/978-3-319-48749-6_43}}, year = {{2016}}, } @article{16146, author = {{Grienitz, Volker and Tröster, Thomas and Meiners, Stefan}}, issn = {{0001-2785}}, journal = {{ATZ - Automobiltechnische Zeitschrift}}, pages = {{36--41}}, title = {{{Technikevaluation für die generative Fertigung eines Serien-Radträgers}}}, doi = {{10.1007/s35148-016-0090-5}}, year = {{2016}}, } @article{139, abstract = {{We consider online optimization problems in which certain goods have to be acquired in order to provide a service or infrastructure. Classically, decisions for such problems are considered as final: one buys the goods. However, in many real world applications, there is a shift away from the idea of buying goods. Instead, leasing is often a more flexible and lucrative business model. Research has realized this shift and recently initiated the theoretical study of leasing models (Anthony and Gupta in Proceedings of the integer programming and combinatorial optimization: 12th International IPCO Conference, Ithaca, NY, USA, June 25–27, 2007; Meyerson in Proceedings of the 46th Annual IEEE Symposium on Foundations of Computer Science (FOCS 2005), 23–25 Oct 2005, Pittsburgh, PA, USA, 2005; Nagarajan and Williamson in Discret Optim 10(4):361–370, 2013) We extend this line of work and suggest a more systematic study of leasing aspects for a class of online optimization problems. We provide two major technical results. We introduce the leasing variant of online set multicover and give an O(log(mK)logn)-competitive algorithm (with n, m, and K being the number of elements, sets, and leases, respectively). Our results also imply improvements for the non-leasing variant of online set cover. Moreover, we extend results for the leasing variant of online facility location. Nagarajan and Williamson (Discret Optim 10(4):361–370, 2013) gave an O(Klogn)-competitive algorithm for this problem (with n and K being the number of clients and leases, respectively). We remove the dependency on n (and, thereby, on time). In general, this leads to a bound of O(lmaxloglmax) (with the maximal lease length lmax). For many natural problem instances, the bound improves to O(K2).}}, author = {{Abshoff, Sebastian and Kling, Peter and Markarian, Christine and Meyer auf der Heide, Friedhelm and Pietrzyk, Peter }}, journal = {{Journal of Combinatorial Optimization}}, number = {{4}}, pages = {{ 1197----1216}}, publisher = {{Springer}}, title = {{{Towards the price of leasing online}}}, doi = {{10.1007/s10878-015-9915-5}}, year = {{2016}}, } @inproceedings{142, abstract = {{For overlay networks, the ability to recover from a variety of problems like membership changes or faults is a key element to preserve their functionality. In recent years, various self-stabilizing overlay networks have been proposed that have the advantage of being able to recover from any illegal state. However, the vast majority of these networks cannot give any guarantees on its functionality while the recovery process is going on. We are especially interested in searchability, i.e., the functionality that search messages for a specific identifier are answered successfully if a node with that identifier exists in the network. We investigate overlay networks that are not only self-stabilizing but that also ensure that monotonic searchability is maintained while the recovery process is going on, as long as there are no corrupted messages in the system. More precisely, once a search message from node u to another node v is successfully delivered, all future search messages from u to v succeed as well. Monotonic searchability was recently introduced in OPODIS 2015, in which the authors provide a solution for a simple line topology.We present the first universal approach to maintain monotonic searchability that is applicable to a wide range of topologies. As the base for our approach, we introduce a set of primitives for manipulating overlay networks that allows us to maintain searchability and show how existing protocols can be transformed to use theses primitives.We complement this result with a generic search protocol that together with the use of our primitives guarantees monotonic searchability.As an additional feature, searching existing nodes with the generic search protocol is as fast as searching a node with any other fixed routing protocol once the topology has stabilized.}}, author = {{Scheideler, Christian and Setzer, Alexander and Strothmann, Thim Frederik}}, booktitle = {{Proceedings of the 30th International Symposium on Distributed Computing (DISC)}}, pages = {{71----84}}, title = {{{Towards a Universal Approach for Monotonic Searchability in Self-stabilizing Overlay Networks}}}, doi = {{10.1007/978-3-662-53426-7_6}}, year = {{2016}}, } @inproceedings{143, abstract = {{We present an efficient parallel algorithm for the general Monotone Circuit Value Problem (MCVP) with n gates and an underlying graph of bounded genus k. Our algorithm generalizes a recent result by Limaye et al. who showed that MCVP with toroidal embedding (genus 1) is in NC when the input contains a toroidal embedding of the circuit. In addition to extending this result from genus 1 to any bounded genus k, and unlike the work reported by Limaye et al., we do not require a precomputed embedding to be given. Most importantly, our results imply that given a P-complete problem, it is possible to find an algorithm that makes the problem fall into NC by fixing one or more parameters. Hence, we deduce the interesting analogy: Fixed Parameter Parallelizable (FPP) is with respect to P-complete what Fixed Parameter Tractable (FPT) is with respect to NP-complete. Similar work that uses treewidth as parameter was also presented by Elberfeld et al. in [6].}}, author = {{Abu-Khzam, Faisal N. and Li, Shouwei and Markarian, Christine and Meyer auf der Heide, Friedhelm and Podlipyan, Pavel}}, booktitle = {{Proceedings of the 22nd International Conference on Computing and Combinatorics (COCOON)}}, pages = {{92--102}}, title = {{{The Monotone Circuit Value Problem with Bounded Genus Is in NC}}}, doi = {{10.1007/978-3-319-42634-1_8}}, year = {{2016}}, } @article{145, abstract = {{Comparative evaluations of peer-to-peer protocols through simulations are a viable approach to judge the performance and costs of the individual protocols in large-scale networks. In order to support this work, we present the peer-to-peer system simulator PeerfactSim.KOM, which we extended over the last years. PeerfactSim.KOM comes with an extensive layer model to support various facets and protocols of peer-to-peer networking. In this article, we describe PeerfactSim.KOM and show how it can be used for detailed measurements of large-scale peer-to-peer networks. We enhanced PeerfactSim.KOM with a fine-grained analyzer concept, with exhaustive automated measurements and gnuplot generators as well as a coordination control to evaluate sets of experiment setups in parallel. Thus, by configuring all experiments and protocols only once and starting the simulator, all desired measurements are performed, analyzed, evaluated, and combined, resulting in a holistic environment for the comparative evaluation of peer-to-peer systems. An immediate comparison of different configurations and overlays under different aspects is possible directly after the execution without any manual post-processing. }}, author = {{Feldotto, Matthias and Graffi, Kalman}}, journal = {{Concurrency and Computation: Practice and Experience}}, number = {{5}}, pages = {{1655--1677}}, publisher = {{Wiley Online Library}}, title = {{{Systematic evaluation of peer-to-peer systems using PeerfactSim.KOM}}}, doi = {{10.1002/cpe.3716}}, volume = {{28}}, year = {{2016}}, } @article{31800, author = {{Häsel-Weide, Uta}}, journal = {{Sonderpädagogische Förderung heute}}, number = {{61}}, pages = {{356--368}}, title = {{{"Merit hat 4 von 5 Subtraktionsaufgaben durch Rückwärtszählen gelöst". Leistungsbeurteilung im inklusiven Mathematikunterricht}}}, volume = {{4}}, year = {{2016}}, } @inbook{31825, author = {{Ballweg, Sandra and Kuhn, Carmen and Hertweck, Lisa}}, booktitle = {{Schreibberatung und Schreibförderung. Impulse aus Theorie, Empirie und Praxis}}, editor = {{Ballweg, Sandra}}, pages = {{137--172}}, publisher = {{Lang}}, title = {{{Schreiberfahrung von Studierenden aus verschiedenen Fächergruppen und deren wahrgenommener Unterstützungsbedarf beim akademischen Schreiben. Ergebnisse einer Querschnittsstudie}}}, year = {{2016}}, } @inbook{31824, author = {{Ballweg, Sandra}}, booktitle = {{Developing and Assessing Academic Writing Skills}}, editor = {{Göpferich, Susanne and Neumann, Imke and Sing, Christine}}, pages = {{143--172}}, publisher = {{Lang}}, title = {{{Portfolios as a means of developing and assessing writing skills}}}, year = {{2016}}, } @book{32054, editor = {{Benholz, Claudia and Frank, Magnus and Niederhaus, Constanze}}, publisher = {{Waxmann Verlag}}, title = {{{Neu zugewanderte Schülerinnen und Schüler – eine Gruppe mit besonderen Potentialen. Beiträge aus Forschung und Schulpraxis}}}, year = {{2016}}, } @article{32076, author = {{Frenzel, Beate and Niederhaus, Constanze}}, journal = {{Die berufsbildende Schule (68)}}, pages = {{181--184}}, title = {{{Unterrichten in Internationalen Förderklassen am Berufskolleg in Nordrhein-Westfalen (NRW)}}}, year = {{2016}}, } @inbook{32077, author = {{Frenzel, Beate and Niederhaus, Constanze and Peschel, Corinna and Rüther, Ann-Kristin}}, booktitle = {{Neu zugewanderte Schülerinnen und Schüler – eine Gruppe mit besonderen Potentialen. Beiträge aus Forschung und Schulpraxis}}, editor = {{Benholz, Claudia and Frank, Magnus and Niederhaus, Constanze}}, pages = {{171--196}}, publisher = {{Waxmann Verlag}}, title = {{{„In unserer Schule sind alle im Grunde ins kalte Wasser gesprungen und alle sind nach ´ner Weile belohnt worden durch große Erfolge.“ Interviews mit Lehrerinnen und Lehrern zu den Besonderheiten des Unterrichtens neu zugewanderter Schülerinnen und Schüler}}}, year = {{2016}}, }