@article{33336, abstract = {{The dipole approximation is employed to describe interactions between atoms and radiation. It essentially consists of neglecting the spatial variation of the external field over the atom. Heuristically, this is justified by arguing that the wavelength is considerably larger than the atomic length scale, which holds under usual experimental conditions. We prove the dipole approximation in the limit of infinite wavelengths compared to the atomic length scale and estimate the rate of convergence. Our results include N-body Coulomb potentials and experimentally relevant electromagnetic fields such as plane waves and laser pulses.}}, author = {{Boßmann, Lea and Grummt, Robert and Kolb, Martin}}, journal = {{Letters in Mathematical Physics}}, pages = {{185–193}}, title = {{{On the dipole approximation with error estimates}}}, doi = {{https://link.springer.com/article/10.1007/s11005-017-0999-y}}, volume = {{108}}, year = {{2017}}, } @article{33342, abstract = {{In this work we consider a one-dimensional Brownian motion with constant drift moving among a Poissonian cloud of obstacles. Our main result proves convergence of the law of processes conditional on survival up to time t as t converges to infinity in the critical case where the drift coincides with the intensity of the Poisson process. This complements a previous result of T. Povel, who considered the same question in the case where the drift is strictly smaller than the intensity. We also show that the end point of the process conditioned on survival up to time t rescaled by √t converges in distribution to a non-trivial random variable, as t tends to infinity, which is in fact invariant with respect to the drift h>0. We thus prove that it is sub-ballistic and estimate the speed of escape. The latter is in a sharp contrast with discrete models of dimension larger or equal to 2 when the behaviour at criticality is ballistic, see [7], and even to many one dimensional models which exhibit ballistic behaviour at criticality, see [8].}}, author = {{Savov, Mladen and Kolb, Martin}}, journal = {{Electronic Journal of Probability}}, publisher = {{ Institute of Mathematical Statistics & Bernoulli Society}}, title = {{{Conditional survival distributions of Brownian trajectories in a one dimensional Poissonian environment in the critical case}}}, doi = {{https://doi.org/10.1214/17-EJP4468}}, volume = {{22}}, year = {{2017}}, } @inproceedings{5829, abstract = {{Websites increasingly embed semantic data for search engine optimization. The most common ontology for semantic data, schema.org, is supported by all major search engines and describes over 500 data types, including calendar events, recipes, products, and TV shows. As of today, users wishing to pass this data to their favorite applications, e.g., their calendars, cookbooks, price comparison applications or even smart devices such as TV receivers, rely on cumbersome and error-prone workarounds such as reentering the data or a series of copy and paste operations. In this paper, we present Semantic Data Mediator (SDM), an approach that allows the easy transfer of semantic data to a multitude of services, ranging from web services to applications installed on different devices. SDM extracts semantic data from the currently displayed web page on the client-side, offers suitable services to the user, and by the press of a button, forwards this data to the desired service while doing all the necessary data conversion and service interface adaptation in between. To realize this, we built a reusable repository of service descriptions, data converters, and service adapters, which can be extended by the crowd. Our approach for linking services to websites relies solely on semantic data and does not require any additional support by either website or service developers. We have fully implemented our approach and present a real-world case study demonstrating its feasibility and usefulness.}}, author = {{Wolters, Dennis and Heindorf, Stefan and Kirchhoff, Jonas and Engels, Gregor}}, booktitle = {{2017 IEEE International Conference on Web Services (ICWS)}}, editor = {{Altintas, Ilkay and Chen, Shiping}}, isbn = {{9781538607527}}, keywords = {{Services, Websites, Semantic Data, schema.org, Data Conversion, Interface Adaptation, Mediation}}, publisher = {{IEEE}}, title = {{{Linking Services to Websites by Leveraging Semantic Data}}}, doi = {{10.1109/icws.2017.80}}, year = {{2017}}, } @inproceedings{6722, abstract = {{We report on the Wikidata vandalism detection task at the WSDM Cup 2017. The task received five submissions for which this paper describes their evaluation and a comparison to state of the art baselines. Unlike previous work, we recast Wikidata vandalism detection as an online learning problem, requiring participant software to predict vandalism in near real-time. The best-performing approach achieves a ROC-AUC of 0.947 at a PR-AUC of 0.458. In particular, this task was organized as a software submission task: to maximize reproducibility as well as to foster future research and development on this task, the participants were asked to submit their working software to the TIRA experimentation platform along with the source code for open source release.}}, author = {{Heindorf, Stefan and Potthast, Martin and Engels, Gregor and Stein, Benno}}, booktitle = {{WSDM Cup 2017 Notebook Papers}}, title = {{{Overview of the Wikidata Vandalism Detection Task at WSDM Cup 2017}}}, year = {{2017}}, } @unpublished{33732, abstract = {{The WSDM Cup 2017 was a data mining challenge held in conjunction with the 10th International Conference on Web Search and Data Mining (WSDM). It addressed key challenges of knowledge bases today: quality assurance and entity search. For quality assurance, we tackle the task of vandalism detection, based on a dataset of more than 82 million user-contributed revisions of the Wikidata knowledge base, all of which annotated with regard to whether or not they are vandalism. For entity search, we tackle the task of triple scoring, using a dataset that comprises relevance scores for triples from type-like relations including occupation and country of citizenship, based on about 10,000 human relevance judgements. For reproducibility sake, participants were asked to submit their software on TIRA, a cloud-based evaluation platform, and they were incentivized to share their approaches open source.}}, author = {{Potthast, Martin and Heindorf, Stefan and Bast, Hannah}}, booktitle = {{arXiv:1712.09528}}, title = {{{Proceedings of the WSDM Cup 2017: Vandalism Detection and Triple Scoring}}}, year = {{2017}}, } @article{34631, author = {{Hesse, Kerstin and Sloan, Ian H. and Womersley, Robert S.}}, issn = {{0029-599X}}, journal = {{Numerische Mathematik}}, keywords = {{Applied Mathematics, Computational Mathematics}}, number = {{3}}, pages = {{579--605}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Radial basis function approximation of noisy scattered data on the sphere}}}, doi = {{10.1007/s00211-017-0886-6}}, volume = {{137}}, year = {{2017}}, } @article{24211, abstract = {{A fully-differential receiver structure for fiber links is presented, in which the photodiode (PD) is DC-coupled to the transimpedance amplifier (TIA) and biased through the feedback resistors. The biasing voltage is defined by the internal structure of the input stage. Different options are suggested that allow to adjust PD biasing. Multiple architecture variants are proposed, that were implemented in 0.25μm SiGe BiCMOS technology. Initial measurement results are reported, proving the feasibility of the concept. A 25Gbps hybrid receiver designed to comply with a specific standard is also presented, featuring large horizontal eye opening of 800mV, OMA of -15dBm at BER of 10 -6 and power dissipation of 330mW from a single 3.3V power supply.}}, author = {{Gudyriev, Sergiy and Scheytt, Christoph and Yan, Lei and Christian, Meuer and Zimmermann, Lars}}, issn = {{ 2378-590X}}, journal = {{IEEE Bipolar/BiCMOS Circuits and Technology Meeting}}, title = {{{Fully-differential, DC-coupled, Self-biased, Monolithically-integrated Optical Receiver in 0.25μm Photonic BiCMOS Technology for Multi-channel Fiber Links}}}, doi = {{10.1109/BCTM.2017.8112922}}, year = {{2017}}, } @inproceedings{24226, author = {{Scheytt, Christoph}}, booktitle = {{W3+Fair on Optoelectronics, Electronics, and Mechanics}}, title = {{{Silicon Photonics Microsystems for Communications and Sensing}}}, year = {{2017}}, } @inproceedings{48305, author = {{Wachsmuth, Henning and Naderi, Nona and Habernal, Ivan and Hou, Yufang and Hirst, Graeme and Gurevych, Iryna and Stein, Benno}}, booktitle = {{Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)}}, publisher = {{Association for Computational Linguistics}}, title = {{{Argumentation Quality Assessment: Theory vs. Practice}}}, doi = {{10.18653/v1/p17-2039}}, year = {{2017}}, } @inproceedings{11763, abstract = {{In this paper, we apply a high-resolution approach, i.e. the matrix pencil method (MPM), to the FMCW automotive radar system to separate the neighboring targets, which share similar parameters, i.e. range, relative speed and azimuth angle, and cause overlapping in the radar spectrum. In order to adapt the 1D model of MPM to the 2D range-velocity spectrum and simultaneously limit the computational cost, some preprocessing steps are proposed to construct a novel separation algorithm. Finally, this algorithm is evaluated in both simulation and real data, and the results indicate a promising performance.}}, author = {{Fei, Tai and Grimm, Christopher and Farhoud, Ridha and Breddermann, Tobias and Warsitz, Ernst and Haeb-Umbach, Reinhold}}, booktitle = {{IEEE International conference on microwave, communications, anthenas and electronic systems}}, title = {{{A Novel Target Separation Algorithm Applied to The Two-Dimensional Spectrum for FMCW Automotive Radar Systems}}}, year = {{2017}}, } @inproceedings{11772, abstract = {{In this paper, we present a hypothesis test for the classification of moving targets in the sight of an automotive radar sensor. For this purpose, a statistical model of the relative velocity between a stationary target and the radar sensor has been developed. With respect to the statistical properties a confidence interval is calculated and targets with relative velocity lying outside this interval are classified as moving targets. Compared to existing algorithms our approach is able to give robust classification independent of the number of observed moving targets and is characterized by an instantaneous classification, a simple parameterization of the model and an automatic calculation of the discriminating threshold.}}, author = {{Grimm, Christopher and Breddermann, Tobias and Farhoud, Ridha and Fei, Tai and Warsitz, Ernst and Haeb-Umbach, Reinhold}}, booktitle = {{IEEE International conference on microwave, communications, anthenas and electronic systems (COMCAS)}}, title = {{{Hypothesis Test for the Detection of Moving Targets in Automotive Radar}}}, year = {{2017}}, } @inproceedings{11759, abstract = {{Variational Autoencoders (VAEs) have been shown to provide efficient neural-network-based approximate Bayesian inference for observation models for which exact inference is intractable. Its extension, the so-called Structured VAE (SVAE) allows inference in the presence of both discrete and continuous latent variables. Inspired by this extension, we developed a VAE with Hidden Markov Models (HMMs) as latent models. We applied the resulting HMM-VAE to the task of acoustic unit discovery in a zero resource scenario. Starting from an initial model based on variational inference in an HMM with Gaussian Mixture Model (GMM) emission probabilities, the accuracy of the acoustic unit discovery could be significantly improved by the HMM-VAE. In doing so we were able to demonstrate for an unsupervised learning task what is well-known in the supervised learning case: Neural networks provide superior modeling power compared to GMMs.}}, author = {{Ebbers, Janek and Heymann, Jahn and Drude, Lukas and Glarner, Thomas and Haeb-Umbach, Reinhold and Raj, Bhiksha}}, booktitle = {{INTERSPEECH 2017, Stockholm, Schweden}}, title = {{{Hidden Markov Model Variational Autoencoder for Acoustic Unit Discovery}}}, year = {{2017}}, } @inbook{46355, abstract = {{In this chapter we present the adaptions of the recently proposed Directed Search method to the context of unconstrained parameter dependent multi-objective optimization problems (PMOPs). The new method, called 𝜆-DS, is capable of performing a movement both toward and along the solution set of a given differentiable PMOP. We first discuss the basic variants of the method that use gradient information and describe subsequently modifications that allow for a gradient free realization. Finally, we show that 𝜆-DS can be used to understand the behavior of stochastic local search within PMOPs to a certain extent which might be interesting for the development of future local search engines, or evolutionary strategies, for the treatment of such problems. We underline all our statements with several numerical results indicating the strength of the novel approach.}}, author = {{Adrián, Sosa Hernández V and Lara, A and Trautmann, Heike and Rudolph, G and Schütze, O}}, booktitle = {{NEO 15}}, editor = {{Schütze, O and Trujillo, L and Legrand, P and Maldonado, Y}}, isbn = {{978-3-319-44003-3}}, pages = {{281–330}}, publisher = {{Springer International Publishing}}, title = {{{The Directed Search Method for Unconstrained Parameter Dependent Multi-objective Optimization Problems}}}, doi = {{10.1007/978-3-319-44003-3_12}}, year = {{2017}}, } @inproceedings{46360, abstract = {{Nowadays customers expect a seamless interaction with companies throughout all available communication channels. However, many companies rely on different software solutions to handle each channel, which leads to heterogeneous IT infrastructures and isolated data sources. Omni-Channel CRM is a holistic approach towards a unified view on the customer across all channels. This paper introduces three case studies which demonstrate challenges of omni-channel CRM and the value it can provide. The first case study shows how to integrate and visualise data from different sources which can support operational and strategic decision. In the second case study, a social media analysis approach is discussed which provides benefits by offering reports of service performance across channels. The third case study applies customer segmentation to an online fashion retailer in order to identify customer profiles.}}, author = {{Carnein, Matthias and Heuchert, Markus and Homann, Leschek and Trautmann, Heike and Vossen, Gottfried and Becker, Jörg and Kraume, Karsten}}, booktitle = {{Proceedings of the 36$^th$ International Conference on Conceptual Modeling (ER’17)}}, editor = {{de Cesare, Sergio and Ulrich, Frank}}, isbn = {{978-3-319-70625-2}}, pages = {{69–78}}, publisher = {{Springer International Publishing}}, title = {{{Towards Efficient and Informative Omni-Channel Customer Relationship Management}}}, doi = {{10.1007/978-3-319-70625-2_7}}, volume = {{10651}}, year = {{2017}}, } @inproceedings{46361, abstract = {{Until recently, customer service was exclusively provided over traditional channels. Cus- tomers could write an email or call a service center if they had questions or problems with a product or service. In recent times, this has changed dramatically as companies explore new channels to offer customer service. With the increasing popularity of social media, more companies thrive to provide customer service also over Facebook and Twitter. Companies aim to provide a better customer ex- perience by offering more convenient channels to contact a company. In addition, this unburdens traditional channels which are costly to maintain. This paper empirically evaluates the performance of customer service in social media by analysing a multitude of companies in the airline industry. We have collected several million customer service requests from Twitter and Facebook and auto- matically analyzed how efficient the service strategies of the respective companies are in terms of response rate and time.}}, author = {{Carnein, Matthias and Homann, Leschek and Trautmann, Heike and Vossen, Gottfried and Kraume, Karsten}}, booktitle = {{Proceedings of the 17$^th$ Conference on Database Systems for Business, Technology, and Web (BTW ’17)}}, editor = {{Ritter, Norbert and Schwarz, Holger and Klettke, Meike and Thor, Andreas and Kopp, Oliver and Bernhard, Matthias Wieland}}, issn = {{978-3-88579-660-2}}, pages = {{33–40}}, publisher = {{Gesellschaft für Informatik}}, title = {{{Customer Service in Social Media — An Empirical Study of the Airline Industry}}}, volume = {{P-266}}, year = {{2017}}, } @inbook{46356, abstract = {{Integrating user preferences in Evolutionary Multiobjective Optimization (EMO) is currently a prevalent research topic. There is a large variety of preference handling methods (originated from Multicriteria decision making, MCDM) and EMO methods, which have been combined in various ways. This paper proposes a Web Ontology Language (OWL) ontology to model and systematize the knowledge of preference-based multiobjective evolutionary algorithms (PMOEAs). Detailed procedure is given on how to build and use the ontology with the help of Protégé. Different use-cases, including training new learners, querying and reasoning are exemplified and show remarkable benefit for both EMO and MCDM communities.}}, author = {{Li, L and Yevseyeva, I and Basto-Fernandes, V and Trautmann, Heike and Jing, N and Emmerich, M}}, booktitle = {{Evolutionary Multi-Criterion Optimization: 9$^th$ International Conference, EMO 2017, Münster, Germany, March 19-22, 2017, Proceedings}}, editor = {{Trautmann, H and Rudolph, G and Klamroth, K and Schütze, O and Wiecek, M and Jin, Y and Grimme, C}}, isbn = {{978-3-319-54157-0}}, pages = {{406–421}}, publisher = {{Springer International Publishing}}, title = {{{Building and Using an Ontology of Preference-Based Multiobjective Evolutionary Algorithms}}}, doi = {{10.1007/978-3-319-54157-0_28}}, year = {{2017}}, } @inbook{46357, abstract = {{The liner shipping fleet repositioning problem (LSFRP) is a central optimization problem within the container shipping industry. Several approaches exist for solving this problem using exact and heuristic techniques, however all of them use a single objective function for determining an optimal solution. We propose a multi-objective approach based on a simulated annealing heuristic so that repositioning coordinators can better balance profit making with cost-savings and environmental sustainability. As the first multi-objective approach in the area of liner shipping routing, we show that giving more options to decision makers need not be costly. Indeed, our approach requires no extra runtime than a weighted objective heuristic and provides a rich set of solutions along the Pareto front.}}, author = {{Tierney, K and Handali, J and Grimme, C and Trautmann, Heike}}, booktitle = {{Evolutionary Multi-Criterion Optimization: 9$^th$ International Conference, EMO 2017, Münster, Germany, March 19-22, 2017, Proceedings}}, editor = {{Trautmann, H and Rudolph, G and Klamroth, K and Schütze, O and Wiecek, M and Jin, Y and Grimme, C}}, isbn = {{978-3-319-54157-0}}, pages = {{622–638}}, publisher = {{Springer International Publishing}}, title = {{{Multi-objective Optimization for Liner Shipping Fleet Repositioning}}}, doi = {{10.1007/978-3-319-54157-0_42}}, year = {{2017}}, } @inproceedings{46359, abstract = {{This paper proposes a new stream clustering algorithm for text streams. The algorithm combines concepts from stream clustering and text analysis in order to incrementally maintain a number of text droplets that represent topics within the stream. Our algorithm adapts to changes of topic over time and can handle noise and outliers gracefully by decaying the importance of irrelevant clusters. We demonstrate the performance of our approach by using more than one million real-world texts from the video streaming platform Twitch.tv.}}, author = {{Carnein, Matthias and Assenmacher, Dennis and Trautmann, Heike}}, booktitle = {{Proceedings of the 36$^th$ International Conference on Conceptual Modeling (ER’17)}}, editor = {{de Cesare, Sergio and Ulrich, Frank}}, isbn = {{978-3-319-70625-2}}, pages = {{79–88}}, publisher = {{Springer International Publishing}}, title = {{{Stream Clustering of Chat Messages with Applications to Twitch Streams}}}, doi = {{10.1007/978-3-319-70625-2_8}}, year = {{2017}}, } @article{46362, abstract = {{Social bots are currently regarded an influential but also somewhat mysterious factor in public discourse and opinion making. They are considered to be capable of massively distributing propaganda in social and online media, and their application is even suspected to be partly responsible for recent election results. Astonishingly, the term social bot is not well defined and different scientific disciplines use divergent definitions. This work starts with a balanced definition attempt, before providing an overview of how social bots actually work (taking the example of Twitter) and what their current technical limitations are. Despite recent research progress in Deep Learning and Big Data, there are many activities bots cannot handle well. We then discuss how bot capabilities can be extended and controlled by integrating humans into the process and reason that this is currently the most promising way to realize meaningful interactions with other humans. This finally leads to the conclusion that hybridization is a challenge for current detection mechanisms and has to be handled with more sophisticated approaches to identify political propaganda distributed with social bots.}}, author = {{Grimme, C and Preuss, M and Adam, L and Trautmann, Heike}}, journal = {{Big Data}}, number = {{4}}, pages = {{279–293}}, title = {{{Social Bots: Human-Like by Means of Human Control?}}}, doi = {{10.1089/big.2017.0044}}, volume = {{5}}, year = {{2017}}, } @inproceedings{46358, abstract = {{Analysing streaming data has received considerable attention over the recent years. A key research area in this field is stream clustering which aims to recognize patterns in a possibly unbounded data stream of varying speed and structure. Over the past decades a multitude of new stream clustering algorithms have been proposed. However, to the best of our knowledge, no rigorous analysis and comparison of the different approaches has been performed. Our paper fills this gap and provides extensive experiments for a total of ten popular algorithms. We utilize a number of standard data sets of both, real and synthetic data and identify key weaknesses and strengths of the existing algorithms.}}, author = {{Carnein, Matthias and Assenmacher, Dennis and Trautmann, Heike}}, booktitle = {{Proceedings of the ACM International Conference on Computing Frontiers (CF ’17)}}, isbn = {{978-1-4503-4487-6/17/05}}, pages = {{361–365}}, title = {{{An Empirical Comparison of Stream Clustering Algorithms}}}, doi = {{10.1145/3075564.3078887}}, year = {{2017}}, }