@inproceedings{9270, abstract = {{As 5G and network function virtualization (NFV) are maturing, it becomes crucial to demonstrate their feasibility and benefits by means of vertical scenarios. While 5GPPP has identified smart manufacturing as one of the most important vertical industries, there is still a lack of specific, practical use cases. Using the experience from a large-scale manufacturing company, Weidm{\"u}ller Group, we present a detailed use case that reflects the needs of real-world manufacturers. We also propose an architecture with specific network services and virtual network functions (VNFs) that realize the use case in practice. As a proof of concept, we implement the required services and deploy them on an emulation-based prototyping platform. Our experimental results indicate that a fully virtualized smart manufacturing use case is not only feasible but also reduces machine interconnection and configuration time and thus improves productivity by orders of magnitude.}}, author = {{Schneider, Stefan Balthasar and Peuster, Manuel and Behnke, Daniel and Marcel, Müller and Bök, Patrick-Benjamin and Karl, Holger}}, booktitle = {{European Conference on Networks and Communications (EuCNC)}}, keywords = {{5g, vertical, smart manufacturing, nfv}}, publisher = {{IEEE}}, title = {{{Putting 5G into Production: Realizing a Smart Manufacturing Vertical Scenario}}}, doi = {{10.1109/eucnc.2019.8802016}}, year = {{2019}}, } @inproceedings{9275, abstract = {{In the last years, store-oriented software ecosystems are gaining more and more attention from a business perspective. In these ecosystems, third-party developers upload extensions to a store which can be downloaded by end users. While the functional scope of such ecosystems is relatively similar, the underlying business models differ greatly in and between their different product domains (e.g. Mobile Phone, Smart TV). This variability, in turn, makes it challenging for store providers to find a business model that fits their own needs. To handle this variability, we introduce the Business Variability Model (BVM) for modeling business model decisions. The basis of these decisions is the analysis of 60 store-oriented software ecosystems in eight different product domains. We map their business model decisions to the Business Model Canvas, condense them to a variability model and discuss particular variants and their dependencies. Our work provides store providers a new approach for modeling business model decisions together with insights of existing business models. This, in turn, supports them in creating new and improving existing business models.}}, author = {{Gottschalk, Sebastian and Rittmeier, Florian and Engels, Gregor}}, booktitle = {{Business Modeling and Software Design}}, editor = {{Shishkov, Boris}}, keywords = {{Software Ecosystems, Business Models, Variabilities}}, location = {{Lisbon}}, pages = {{153--169}}, publisher = {{Springer International Publishing}}, title = {{{Business Models of Store-Oriented Software Ecosystems: A Variability Modeling Approach}}}, doi = {{10.1007/978-3-030-24854-3_10}}, year = {{2019}}, } @article{8113, abstract = {{The ongoing softwarization of networks creates a big need for automated testing solutions to ensure service quality. This becomes even more important if agile environments with short time to market and high demands, in terms of service performance and availability, are considered. In this paper, we introduce a novel testing solution for virtualized, microservice-based network functions and services, which we base on TTCN-3, a well known testing language defined by the European standards institute (ETSI). We use TTCN-3 not only for functional testing but also answer the question whether TTCN-3 can be used for performance profiling tasks as well. Finally, we demonstrate the proposed concepts and solutions in a case study using our open-source prototype to test and profile a chained network service.}}, author = {{Peuster, Manuel and Dröge, Christian and Boos, Clemens and Karl, Holger}}, issn = {{2405-9595}}, journal = {{ICT Express}}, publisher = {{Elsevier BV}}, title = {{{Joint testing and profiling of microservice-based network services using TTCN-3}}}, doi = {{10.1016/j.icte.2019.02.001}}, year = {{2019}}, } @misc{8312, author = {{Bäumer, Frederik Simon and Geierhos, Michaela}}, booktitle = {{encyclopedia.pub}}, keywords = {{OTF Computing, Natural Language Processing, Requirements Engineering}}, publisher = {{MDPI}}, title = {{{Requirements Engineering in OTF-Computing}}}, year = {{2019}}, } @article{5674, abstract = {{In disaster operations management, a challenging task for rescue organizations occurs when they have to assign and schedule their rescue units to emerging incidents under time pressure in order to reduce the overall resulting harm. Of particular importance in practical scenarios is the need to consider collaboration of rescue units. This task has hardly been addressed in the literature. We contribute to both modeling and solving this problem by (1) conceptualizing the situation as a type of scheduling problem, (2) modeling it as a binary linear minimization problem, (3) suggesting a branch-and-price algorithm, which can serve as both an exact and heuristic solution procedure, and (4) conducting computational experiments - including a sensitivity analysis of the effects of exogenous model parameters on execution times and objective value improvements over a heuristic suggested in the literature - for different practical disaster scenarios. The results of our computational experiments show that most problem instances of practically feasible size can be solved to optimality within ten minutes. Furthermore, even when our algorithm is terminated once the first feasible solution has been found, this solution is in almost all cases competitive to the optimal solution and substantially better than the solution obtained by the best known algorithm from the literature. This performance of our branch-and-price algorithm enables rescue organizations to apply our procedure in practice, even when the time for decision making is limited to a few minutes. By addressing a very general type of scheduling problem, our approach applies to various scheduling situations.}}, author = {{Rauchecker, Gerhard and Schryen, Guido}}, journal = {{European Journal of Operational Research}}, keywords = {{OR in disaster relief, disaster operations management, scheduling, branch-and-price}}, number = {{1}}, pages = {{352 -- 363}}, publisher = {{Elsevier}}, title = {{{An Exact Branch-and-Price Algorithm for Scheduling Rescue Units during Disaster Response}}}, volume = {{272}}, year = {{2019}}, } @inbook{7430, author = {{Rittmeier, Florian and Engels, Gregor and Teetz, Alexander}}, booktitle = {{Business Process Management Workshops}}, editor = {{Daniel, Florian and Sheng, Quan Z. and Motahari, Hamid}}, isbn = {{9783030116408}}, issn = {{1865-1348}}, pages = {{531--542}}, publisher = {{Springer International Publishing}}, title = {{{Process Weakness Patterns for the Identification of Digitalization Potentials in Business Processes}}}, doi = {{10.1007/978-3-030-11641-5_42}}, volume = {{342}}, year = {{2019}}, } @inproceedings{7668, author = {{Heindorf, Stefan and Scholten, Yan and Engels, Gregor and Potthast, Martin}}, booktitle = {{WWW}}, location = {{San Francisco, USA}}, pages = {{670--680}}, publisher = {{ACM}}, title = {{{Debiasing Vandalism Detection Models at Wikidata}}}, doi = {{10.1145/3308558.3313507}}, year = {{2019}}, } @article{8424, abstract = {{The vision of On-the-Fly (OTF) Computing is to compose and provide software services ad hoc, based on requirement descriptions in natural language. Since non-technical users write their software requirements themselves and in unrestricted natural language, deficits occur such as inaccuracy and incompleteness. These deficits are usually met by natural language processing methods, which have to face special challenges in OTF Computing because maximum automation is the goal. In this paper, we present current automatic approaches for solving inaccuracies and incompletenesses in natural language requirement descriptions and elaborate open challenges. In particular, we will discuss the necessity of domain-specific resources and show why, despite far-reaching automation, an intelligent and guided integration of end users into the compensation process is required. In this context, we present our idea of a chat bot that integrates users into the compensation process depending on the given circumstances. }}, author = {{Bäumer, Frederik Simon and Kersting, Joschka and Geierhos, Michaela}}, issn = {{2073-431X}}, journal = {{Computers}}, keywords = {{Inaccuracy Detection, Natural Language Software Requirements, Chat Bot}}, location = {{Vilnius, Lithuania}}, number = {{1}}, publisher = {{MDPI AG, Basel, Switzerland}}, title = {{{Natural Language Processing in OTF Computing: Challenges and the Need for Interactive Approaches}}}, doi = {{10.3390/computers8010022}}, volume = {{8}}, year = {{2019}}, } @inproceedings{8529, author = {{Seemann, Nina and Merten, Marie-Luis}}, booktitle = {{DHd 2019 Digital Humanities: multimedial & multimodal. Konferenzabstracts}}, editor = {{Sahle, Patrick}}, isbn = {{978-3-00-062166-6}}, location = {{Mainz and Frankfurt am Main, Germany}}, pages = {{352--353}}, publisher = {{Zenodo}}, title = {{{UPB-Annotate: Ein maßgeschneidertes Toolkit für historische Texte}}}, doi = {{10.5281/ZENODO.2596094}}, year = {{2019}}, } @inproceedings{8532, author = {{Bäumer, Frederik Simon and Buff, Bianca and Geierhos, Michaela}}, booktitle = {{DHd 2019 Digital Humanities: multimedial & multimodal. Konferenzabstracts}}, editor = {{Sahle, Patrick}}, isbn = {{978-3-00-062166-6}}, location = {{Mainz and Frankfurt am Main, Germany}}, pages = {{192--193}}, publisher = {{Zenodo}}, title = {{{Potentielle Privatsphäreverletzungen aufdecken und automatisiert sichtbar machen}}}, doi = {{10.5281/zenodo.2596095}}, year = {{2019}}, } @inproceedings{8792, abstract = {{5G together with software defined networking (SDN) and network function virtualisation (NFV) will enable a wide variety of vertical use cases. One of them is the smart man- ufacturing case which utilises 5G networks to interconnect production machines, machine parks, and factory sites to enable new possibilities in terms of flexibility, automation, and novel applications (industry 4.0). However, the availability of realistic and practical proof-of-concepts for those smart manufacturing scenarios is still limited. This demo fills this gap by not only showing a real-world smart manufacturing application entirely implemented using NFV concepts, but also a lightweight prototyping framework that simplifies the realisation of vertical NFV proof-of-concepts. Dur- ing the demo, we show how an NFV-based smart manufacturing scenario can be specified, on-boarded, and instantiated before we demonstrate how the presented NFV services simplify machine data collection, aggregation, and analysis.}}, author = {{Peuster, Manuel and Schneider, Stefan Balthasar and Behnke, Daniel and Müller, Marcel and Bök, Patrick-Benjamin and Karl, Holger}}, booktitle = {{5th IEEE International Conference on Network Softwarization (NetSoft 2019)}}, location = {{Paris}}, title = {{{Prototyping and Demonstrating 5G Verticals: The Smart Manufacturing Case}}}, doi = {{10.1109/NETSOFT.2019.8806685}}, year = {{2019}}, } @article{8795, abstract = {{Softwarized networks are the key enabler for elastic, on-demand service deployments of virtualized network functions. They allow to dynamically steer traffic through the network when new network functions are instantiated, or old ones are terminated. These scenarios become in particular challenging when stateful functions are involved, necessitating state management solutions to migrate state between the functions. The problem with existing solutions is that they typically embrace state migration and flow rerouting jointly, imposing a huge set of requirements on the on-boarded virtualized network functions (VNFs), eg, solution-specific state management interfaces. To change this, we introduce the seamless handover protocol (SHarP). An easy-to-use, loss-less, and order-preserving flow rerouting mechanism that is not fixed to a single state management approach. Using SHarP, VNF vendors are empowered to implement or use the state management solution of their choice. SHarP supports these solutions with additional information when flows are migrated. In this paper, we present SHarP's design, its open source prototype implementation, and show how SHarP significantly reduces the buffer usage at a central (SDN) controller, which is a typical bottleneck in state-of-the-art solutions. Our experiments show that SHarP uses a constant amount of controller buffer, irrespective of the time taken to migrate the VNF state.}}, author = {{Peuster, Manuel and Küttner, Hannes and Karl, Holger}}, issn = {{1055-7148}}, journal = {{International Journal of Network Management}}, title = {{{A flow handover protocol to support state migration in softwarized networks}}}, doi = {{10.1002/nem.2067}}, year = {{2019}}, } @article{8797, abstract = {{Free from phase-matching constraints, plasmonic metasurfaces have contributed significantly to the control of optical nonlinearity and enhancement of nonlinear generation efficiency by engineering subwavelength meta-atoms. However, high dissipative losses and inevitable thermal heating limit their applicability in nonlinear nanophotonics. All-dielectric metasurfaces, supporting both electric and magnetic Mie-type resonances in their nanostructures, have appeared as a promising alternative to nonlinear plasmonics. High-index dielectric nanostructures, allowing additional magnetic resonances, can induce magnetic nonlinear effects, which, along with electric nonlinearities, increase the nonlinear conversion efficiency. In addition, low dissipative losses and high damage thresholds provide an extra degree of freedom for operating at high pump intensities, resulting in a considerable enhancement of the nonlinear processes. We discuss the current state of the art in the intensely developing area of all-dielectric nonlinear nanostructures and metasurfaces, including the role of Mie modes, Fano resonances, and anapole moments for harmonic generation, wave mixing, and ultrafast optical switching. Furthermore, we review the recent progress in the nonlinear phase and wavefront control using all-dielectric metasurfaces. We discuss techniques to realize all-dielectric metasurfaces for multifunctional applications and generation of second-order nonlinear processes from complementary metal–oxide–semiconductor-compatible materials.}}, author = {{Sain, Basudeb and Meier, Cedrik and Zentgraf, Thomas}}, issn = {{2577-5421}}, journal = {{Advanced Photonics}}, number = {{2}}, pages = {{024002}}, title = {{{Nonlinear optics in all-dielectric nanoantennas and metasurfaces: a review}}}, doi = {{10.1117/1.ap.1.2.024002}}, volume = {{1}}, year = {{2019}}, } @article{9824, author = {{Peuster, Manuel and Schneider, Stefan Balthasar and Zhao, Mengxuan and Xilouris, George and Trakadas, Panagiotis and Vicens, Felipe and Tavernier, Wouter and Soenen, Thomas and Vilalta, Ricard and Andreou, George and Kyriazis, Dimosthenis and Karl, Holger}}, issn = {{0163-6804}}, journal = {{IEEE Communications Magazine}}, pages = {{96--102}}, title = {{{Introducing Automated Verification and Validation for Virtualized Network Functions and Services}}}, doi = {{10.1109/mcom.2019.1800873}}, year = {{2019}}, } @article{6512, abstract = {{Scheduling problems are essential for decision making in many academic disciplines, including operations management, computer science, and information systems. Since many scheduling problems are NP-hard in the strong sense, there is only limited research on exact algorithms and how their efficiency scales when implemented on parallel computing architectures. We address this gap by (1) adapting an exact branch-and-price algorithm to a parallel machine scheduling problem on unrelated machines with sequence- and machine-dependent setup times, (2) parallelizing the adapted algorithm by implementing a distributed-memory parallelization with a master/worker approach, and (3) conducting extensive computational experiments using up to 960 MPI processes on a modern high performance computing cluster. With our experiments, we show that the efficiency of our parallelization approach can lead to superlinear speedup but can vary substantially between instances. We further show that the wall time of serial execution can be substantially reduced through our parallelization, in some cases from 94 hours to less than six minutes when our algorithm is executed on 960 processes.}}, author = {{Rauchecker, Gerhard and Schryen, Guido}}, journal = {{Computers & Operations Research}}, keywords = {{parallel machine scheduling with setup times, parallel branch-and-price algorithm, high performance computing, master/worker parallelization}}, number = {{104}}, pages = {{338--357}}, publisher = {{Elsevier}}, title = {{{Using High Performance Computing for Unrelated Parallel Machine Scheduling with Sequence-Dependent Setup Times: Development and Computational Evaluation of a Parallel Branch-and-Price Algorithm}}}, year = {{2019}}, } @inproceedings{6514, abstract = {{Recommender Agents (RAs) facilitate consumers’ online purchase decisions for complex, multi-attribute products. As not all combinations of attribute levels can be obtained, users are forced into trade-offs. The exposure of trade-offs in a RA has been found to affect consumers’ perceptions. However, little is known about how different preference elicitation methods in RAs affect consumers by varying degrees of trade-off exposure. We propose a research model that investigates how different levels of trade-off exposure cognitively and affectively influence consumers’ satisfaction with RAs. We operationalize these levels in three different RA types and test our hypotheses in a laboratory experiment with 116 participants. Our results indicate that with increasing tradeoff exposure, perceived enjoyment and perceived control follow an inverted Ushaped relationship. Hence, RAs using preference elicitation methods with medium trade-off exposure yield highest consumer satisfaction. This contributes to the understanding of trade-offs in RAs and provides valuable implications to e-commerce practitioners.}}, author = {{Schuhbeck, Veronika and Siegfried, Nils and Dorner, Verena and Benlian, Alexander and Scholz, Michael and Schryen, Guido}}, booktitle = {{Proceedings of the 14. Internationale Tagung Wirtschaftsinformatik}}, keywords = {{Recommender Agents, Preference Elicitation Method, Trade-off Exposure, Customer Satisfaction}}, location = {{Siegen, Germany}}, pages = {{55--64}}, title = {{{Walking the Middle Path: How Medium Trade-off Exposure Leads to Higher Consumer Satisfaction in Recommender Agents}}}, year = {{2019}}, } @inproceedings{6860, author = {{Afifi, Haitham and Karl, Holger}}, booktitle = {{2019 16th IEEE Annual Consumer Communications & Networking Conference (CCNC2019)}}, publisher = {{IEEE}}, title = {{{Power Allocation with a Wireless Multi-cast Aware Routing for Virtual Network Embedding}}}, year = {{2019}}, } @techreport{16847, abstract = {{In this work we describe our results achieved in the ProtestNews Lab at CLEF 2019. To tackle the problems of event sentence detection and event extraction we decided to use contextualized string embeddings. The models were trained on a data corpus collected from Indian news sources, but evaluated on data obtained from news sources from other countries as well, such as China. Our models have obtained competitive results and have scored 3rd in the event sentence detection task and 1st in the event extraction task based on average F1-scores for different test datasets.}}, author = {{Skitalinskaya, Gabriella and Klaff, Jonas and Spliethöver, Maximilian}}, pages = {{7}}, title = {{{CLEF ProtestNews Lab 2019: Contextualized Word Embeddings for Event Sentence Detection and Event Extraction}}}, volume = {{2380}}, year = {{2019}}, } @inproceedings{11965, abstract = {{We present an unsupervised training approach for a neural network-based mask estimator in an acoustic beamforming application. The network is trained to maximize a likelihood criterion derived from a spatial mixture model of the observations. It is trained from scratch without requiring any parallel data consisting of degraded input and clean training targets. Thus, training can be carried out on real recordings of noisy speech rather than simulated ones. In contrast to previous work on unsupervised training of neural mask estimators, our approach avoids the need for a possibly pre-trained teacher model entirely. We demonstrate the effectiveness of our approach by speech recognition experiments on two different datasets: one mainly deteriorated by noise (CHiME 4) and one by reverberation (REVERB). The results show that the performance of the proposed system is on par with a supervised system using oracle target masks for training and with a system trained using a model-based teacher.}}, author = {{Drude, Lukas and Heymann, Jahn and Haeb-Umbach, Reinhold}}, booktitle = {{INTERSPEECH 2019, Graz, Austria}}, title = {{{Unsupervised training of neural mask-based beamforming}}}, year = {{2019}}, } @inproceedings{12874, abstract = {{We propose a training scheme to train neural network-based source separation algorithms from scratch when parallel clean data is unavailable. In particular, we demonstrate that an unsupervised spatial clustering algorithm is sufficient to guide the training of a deep clustering system. We argue that previous work on deep clustering requires strong supervision and elaborate on why this is a limitation. We demonstrate that (a) the single-channel deep clustering system trained according to the proposed scheme alone is able to achieve a similar performance as the multi-channel teacher in terms of word error rates and (b) initializing the spatial clustering approach with the deep clustering result yields a relative word error rate reduction of 26% over the unsupervised teacher.}}, author = {{Drude, Lukas and Hasenklever, Daniel and Haeb-Umbach, Reinhold}}, booktitle = {{ICASSP 2019, Brighton, UK}}, title = {{{Unsupervised Training of a Deep Clustering Model for Multichannel Blind Source Separation}}}, year = {{2019}}, }