@inproceedings{3265, abstract = {{We present CLARC (Cryptographic Library for Anonymous Reputation and Credentials), an anonymous credentials system (ACS) combined with an anonymous reputation system. Using CLARC, users can receive attribute-based credentials from issuers. They can efficiently prove that their credentials satisfy complex (access) policies in a privacy-preserving way. This implements anonymous access control with complex policies. Furthermore, CLARC is the first ACS that is combined with an anonymous reputation system where users can anonymously rate services. A user who gets access to a service via a credential, also anonymously receives a review token to rate the service. If a user creates more than a single rating, this can be detected by anyone, preventing users from spamming ratings to sway public opinion. To evaluate feasibility of our construction, we present an open-source prototype implementation.}}, author = {{Bemmann, Kai and Blömer, Johannes and Bobolz, Jan and Bröcher, Henrik and Diemert, Denis Pascal and Eidens, Fabian and Eilers, Lukas and Haltermann, Jan Frederik and Juhnke, Jakob and Otour, Burhan and Porzenheim, Laurens Alexander and Pukrop, Simon and Schilling, Erik and Schlichtig, Michael and Stienemeier, Marcel}}, booktitle = {{Proceedings of the 13th International Conference on Availability, Reliability and Security - ARES '18}}, isbn = {{978-1-4503-6448-5}}, location = {{Hamburg, Germany}}, publisher = {{ACM}}, title = {{{Fully-Featured Anonymous Credentials with Reputation System}}}, doi = {{10.1145/3230833.3234517}}, year = {{2018}}, } @inproceedings{3345, abstract = {{Dynamically steering flows through virtualized net- work function instances is a key enabler for elastic, on-demand deployments of virtualized network functions. This becomes par- ticular challenging when stateful functions are involved, necessi- tating state management. 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 VNFs, e.g., solution-specific state management interfaces. In this paper, we introduce the seamless handover proto- col (SHarP). It provides an easy-to-use, loss-less, and order- preserving flow rerouting mechanism that is not fixed to a single state management approach. This allows VNF vendors to implement or use the state management solution of their choice. SHarP supports these solutions with additional information when flows are migrated. Further, we show how SHarP significantly reduces the buffer usage at a central (SDN) controller, which is a typical bottleneck in existing 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}}, booktitle = {{4th IEEE International Conference on Network Softwarization (NetSoft 2018)}}, location = {{Montreal}}, title = {{{ Let the state follow its flows: An SDN-based flow handover protocol to support state migration}}}, doi = {{10.1109/NETSOFT.2018.8460007}}, year = {{2018}}, } @inproceedings{3346, abstract = {{Developing a virtualized network service does not only involve the implementation and configuration of the network functions it is composed of but also its integration and test with management solutions that will control the service in its production environment. These integration tasks require testbeds that offer the needed network function virtualization infrastructure~(NFVI), like OpenStack, introducing a lot of management and maintenance overheads. Such testbed setups become even more complicated when the multi point-of-presence~(PoP) case, with multiple infrastructure installations, is considered. In this demo, we showcase an emulation platform that executes containerized network services in user-defined multi-PoP topologies. The platform does not only allow network service developers to locally test their services but also to connect real-world management and orchestration solutions to the emulated PoPs. During our interactive demonstration we focus on the integration between the emulated infrastructure and state-of-the-art orchestration solutions like SONATA or OSM.}}, author = {{Peuster, Manuel and Kampmeyer, Johannes and Karl, Holger}}, booktitle = {{4th IEEE International Conference on Network Softwarization (NetSoft 2018)}}, location = {{Montreal}}, title = {{{Containernet 2.0: A Rapid Prototyping Platform for Hybrid Service Function Chains}}}, doi = {{10.1109/NETSOFT.2018.8459905}}, year = {{2018}}, } @inproceedings{3347, abstract = {{Management and orchestration~(MANO) systems are the key components of future large-scale NFV environments. They will manage resources of hundreds or even thousands of NFV infrastructure installations, so called points of presence~(PoP). Such scenarios need to be automatically tested during the development phase of a MANO system. This task becomes very challenging because large-scale NFV testbeds are hard to maintain, too expensive, or simply not available. In this paper, we present a multi-PoP NFV infrastructure emulation platform that enables automated, large-scale testing of MANO stacks. We show that our platform can easily emulate hundreds of PoPs on a single physical machine and reduces the setup time of a test PoP by a factor of 232x compared to a DevStack-based test PoP installation. Further, we present a case study in which we test ETSI's Open Source MANO~(OSM) against our proposed system to gain insights about OSM's behaviour in large-scale NFV deployments.}}, author = {{Peuster, Manuel and Marchetti, Michael and Garcia de Blas, Gerado and Karl, Holger}}, booktitle = {{European Conference on Networks and Communications (EuCNC)}}, location = {{Ljubljana}}, title = {{{Emulation-based Smoke Testing of NFV Orchestrators in Large Multi-PoP Environments}}}, doi = {{10.1109/EuCNC.2018.8442701}}, year = {{2018}}, } @article{3510, abstract = {{Automated machine learning (AutoML) seeks to automatically select, compose, and parametrize machine learning algorithms, so as to achieve optimal performance on a given task (dataset). Although current approaches to AutoML have already produced impressive results, the field is still far from mature, and new techniques are still being developed. In this paper, we present ML-Plan, a new approach to AutoML based on hierarchical planning. To highlight the potential of this approach, we compare ML-Plan to the state-of-the-art frameworks Auto-WEKA, auto-sklearn, and TPOT. In an extensive series of experiments, we show that ML-Plan is highly competitive and often outperforms existing approaches.}}, author = {{Mohr, Felix and Wever, Marcel Dominik and Hüllermeier, Eyke}}, issn = {{1573-0565}}, journal = {{Machine Learning}}, keywords = {{AutoML, Hierarchical Planning, HTN planning, ML-Plan}}, location = {{Dublin, Ireland}}, pages = {{1495--1515}}, publisher = {{Springer}}, title = {{{ML-Plan: Automated Machine Learning via Hierarchical Planning}}}, doi = {{10.1007/s10994-018-5735-z}}, year = {{2018}}, } @inproceedings{3552, author = {{Mohr, Felix and Wever, Marcel Dominik and Hüllermeier, Eyke}}, booktitle = {{Proceedings of the Symposium on Intelligent Data Analysis}}, location = {{‘s-Hertogenbosch, the Netherlands}}, title = {{{Reduction Stumps for Multi-Class Classification}}}, doi = {{10.1007/978-3-030-01768-2_19}}, year = {{2018}}, } @article{3740, abstract = {{Oblique propagation of semi-guided waves across slab waveguide structures with bent corners is investigated. A critical angle can be defined beyond which all radiation losses are suppressed. Additionally an increase of the curvature radius of the bends also leads to low-loss configurations for incidence angles below that critical angle. A combination of two bent corner systems represents a step-like structure, behaving like a Fabry-Perot interferometer, with two partial reflectors separated by the vertical height between the horizontal slabs. We numerically analyse typical high-index-contrast Si/SiO2 structures for their reflectance and transmittance properties. When increasing the curvature radius the resonant effect becomes less relevant such that full transmittance is reached with less critical conditions on the vertical distance or the incidence angle. For practical interest 3-D problems are considered, where the structures are excited by the fundamental mode of a wide, shallow rib waveguide. High transmittance levels can be observed also for these 3-D configurations depending on the width of the rib.}}, author = {{Ebers, Lena and Hammer, Manfred and Förstner, Jens}}, journal = {{Optics Express}}, keywords = {{tet_topic_waveguide}}, number = {{14}}, pages = {{18621--18632}}, publisher = {{OSA Publishing}}, title = {{{Oblique incidence of semi-guided planar waves on slab waveguide steps: effects of rounded edges}}}, doi = {{10.1364/OE.26.018621}}, volume = {{26}}, year = {{2018}}, } @inproceedings{3852, abstract = {{In automated machine learning (AutoML), the process of engineering machine learning applications with respect to a specific problem is (partially) automated. Various AutoML tools have already been introduced to provide out-of-the-box machine learning functionality. More specifically, by selecting machine learning algorithms and optimizing their hyperparameters, these tools produce a machine learning pipeline tailored to the problem at hand. Except for TPOT, all of these tools restrict the maximum number of processing steps of such a pipeline. However, as TPOT follows an evolutionary approach, it suffers from performance issues when dealing with larger datasets. In this paper, we present an alternative approach leveraging a hierarchical planning to configure machine learning pipelines that are unlimited in length. We evaluate our approach and find its performance to be competitive with other AutoML tools, including TPOT.}}, author = {{Wever, Marcel Dominik and Mohr, Felix and Hüllermeier, Eyke}}, booktitle = {{ICML 2018 AutoML Workshop}}, keywords = {{automated machine learning, complex pipelines, hierarchical planning}}, location = {{Stockholm, Sweden}}, title = {{{ML-Plan for Unlimited-Length Machine Learning Pipelines}}}, year = {{2018}}, } @article{3152, abstract = {{To adapt to continuously changing workloads in networks, components of the running network services may need to be replicated (scaling the network service) and allocated to physical resources (placement) dynamically, also necessitating dynamic re-routing of flows between service components. In this paper, we propose JASPER, a fully automated approach to jointly optimizing scaling, placement, and routing for complex network services, consisting of multiple (virtualized) components. JASPER handles multiple network services that share the same substrate network; services can be dynamically added or removed and dynamic workload changes are handled. Our approach lets service designers specify their services on a high level of abstraction using service templates. JASPER automatically makes scaling, placement and routing decisions, enabling quick reaction to changes. We formalize the problem, analyze its complexity, and develop two algorithms to solve it. Extensive empirical results show the applicability and effectiveness of the proposed approach.}}, author = {{Dräxler, Sevil and Karl, Holger and Mann, Zoltan Adam}}, journal = {{IEEE Transactions on Network and Service Management}}, publisher = {{IEEE}}, title = {{{JASPER: Joint Optimization of Scaling, Placement, and Routing of Virtual Network Services}}}, doi = {{10.1109/TNSM.2018.2846572}}, year = {{2018}}, } @inproceedings{2109, abstract = {{In multinomial classification, reduction techniques are commonly used to decompose the original learning problem into several simpler problems. For example, by recursively bisecting the original set of classes, so-called nested dichotomies define a set of binary classification problems that are organized in the structure of a binary tree. In contrast to the existing one-shot heuristics for constructing nested dichotomies and motivated by recent work on algorithm configuration, we propose a genetic algorithm for optimizing the structure of such dichotomies. A key component of this approach is the proposed genetic representation that facilitates the application of standard genetic operators, while still supporting the exchange of partial solutions under recombination. We evaluate the approach in an extensive experimental study, showing that it yields classifiers with superior generalization performance.}}, author = {{Wever, Marcel Dominik and Mohr, Felix and Hüllermeier, Eyke}}, booktitle = {{Proceedings of the Genetic and Evolutionary Computation Conference, GECCO 2018, Kyoto, Japan, July 15-19, 2018}}, keywords = {{Classification, Hierarchical Decomposition, Indirect Encoding}}, location = {{Kyoto, Japan}}, publisher = {{ACM}}, title = {{{Ensembles of Evolved Nested Dichotomies for Classification}}}, doi = {{10.1145/3205455.3205562}}, year = {{2018}}, } @unpublished{21634, abstract = {{Predictive control of power electronic systems always requires a suitable model of the plant. Using typical physics-based white box models, a trade-off between model complexity (i.e. accuracy) and computational burden has to be made. This is a challenging task with a lot of constraints, since the model order is directly linked to the number of system states. Even though white-box models show suitable performance in most cases, parasitic real-world effects often cannot be modeled satisfactorily with an expedient computational load. Hence, a Koopman operator-based model reduction technique is presented which directly links the control action to the system's outputs in a black-box fashion. The Koopman operator is a linear but infinite-dimensional operator describing the dynamics of observables of nonlinear autonomous dynamical systems which can be nicely applied to the switching principle of power electronic devices. Following this data-driven approach, the model order and the number of system states are decoupled which allows us to consider more complex systems. Extensive experimental tests with an automotive-type permanent magnet synchronous motor fed by an IGBT 2-level inverter prove the feasibility of the proposed modeling technique in a finite-set model predictive control application.}}, author = {{Hanke, Sören and Peitz, Sebastian and Wallscheid, Oliver and Klus, Stefan and Böcker, Joachim and Dellnitz, Michael}}, booktitle = {{arXiv:1804.00854}}, title = {{{Koopman Operator-Based Finite-Control-Set Model Predictive Control for Electrical Drives}}}, year = {{2018}}, } @article{1765, author = {{Huang, Lingling and Zhang, Shuang and Zentgraf, Thomas}}, issn = {{2192-8614}}, journal = {{Nanophotonics}}, number = {{6}}, pages = {{1169--1190}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Metasurface holography: from fundamentals to applications}}}, doi = {{10.1515/nanoph-2017-0118}}, volume = {{7}}, year = {{2018}}, } @unpublished{17713, author = {{Wever, Marcel Dominik and Mohr, Felix and Hüllermeier, Eyke}}, publisher = {{Arxiv}}, title = {{{Automated Multi-Label Classification based on ML-Plan}}}, year = {{2018}}, } @unpublished{17714, author = {{Mohr, Felix and Wever, Marcel Dominik and Hüllermeier, Eyke}}, title = {{{Automated machine learning service composition}}}, year = {{2018}}, } @inproceedings{22183, abstract = {{Function integration is a key issue for an efficient and economic usage of Additive Manufacturing. An efficient heat transfer by topology optimized structures is a rarely considered approach which will be outlined with an exemplary electronic housing which has been newly designed. A commercial projector unit, whose electrical components in total produce 38 W, shall be integrated in the closed housing and passively cooled by natural convection. Topology optimized structures shall be generated in the inner part of the housing to transfer the heat homogenously from the projector components to the housing wall while simultaneously minimizing the mass. At the outside of the housing walls, lattice and rib structures are applied to increase the effective surface for heat transfer by natural convection and radiation. Furthermore, the housing geometry is optimized regarding a minimization of support structures to reduce the post-processing effort. Finally, the housing shall be built of AlSi10Mg by SLM.}}, author = {{Menge, Dennis and Delfs, Patrick and Töws, Marcel and Schmid, Hans-Joachim}}, booktitle = {{29th Annual International Solid Freeform Fabrication Symposium}}, pages = {{687--697}}, title = {{{Topology Optimized Heat Transfer Using the Example of an Electronic Housing}}}, volume = {{29}}, year = {{2018}}, } @inproceedings{2332, abstract = {{Ein wichtiges Element der Digitalen Transformation ist die Digitalisierung der Prozesse in Unternehmen. Eine Herausforderung besteht hierbei in der systematischen Erkennung von Digitalisierungspotenzialen in Prozessen. Bestehende Ansätze benötigen Experten, welche Potenziale über ihre Erfahrung oder zeitaufwendig mithilfe von Musterkatalogen identifizieren. In diesem Artikel werden verschiedene Digitalisierungspotenziale klassifiziert und Muster für ein zukünftiges musterbasiertes Analyseverfahren zur automatisierten Identifikation von Digitalisierungspotenzialen in BPMN-Diagrammen beschrieben. Im Vergleich zu bestehenden Ansätzen erlaubt es Experten die Identifizierung von Digitalisierungspotenzialen effizienter und effektiver durchzuführen.}}, author = {{Rittmeier, Florian and Engels, Gregor and Teetz, Alexander}}, booktitle = {{Joint Proceedings of the Workshops at Modellierung 2018 co-located with Modellierung 2018, Braunschweig, Germany, February 21, 2018.}}, keywords = {{Digitalisierungspotenziale, BPI, Digitale Transformation, Information Flow-Modellierung, Patterns, Requirements Engineering}}, pages = {{215----221}}, publisher = {{CEUR-WS.org}}, title = {{{Digitalisierungspotenziale in Geschäftsprozessen effizient und effektiv erkennen (Effective and Efficient Identification of Digitalization Potentials in Business Processes)}}}, volume = {{2060}}, year = {{2018}}, } @book{21817, author = {{Goller, Michael}}, isbn = {{978-3-946023-04-3}}, keywords = {{Bahnhofsmission, Survey Feedback, Monitoring}}, pages = {{200}}, publisher = {{IN VIA Verlag}}, title = {{{Monitoring für die Bahnhofsmissionen: Ein datengestütztes Instrument zur Organisationsentwicklung. Projektbeschreibung und Ergebnisdarstellung}}}, year = {{2018}}, } @inproceedings{7766, author = {{Schumacher, Jan}}, booktitle = {{Beiträge zum Mathematikunterricht 2018}}, publisher = {{WTM-Verlag}}, title = {{{Semiotische Analyse von Sinnkonstruktionsprozessen bei einem innermathematischen Zugang zum Erlernen negativer Zahlen}}}, year = {{2018}}, } @inproceedings{5675, abstract = {{When responding to natural disasters, professional relief units are often supported by many volunteers which are not affiliated to humanitarian organizations. The effective coordination of these volunteers is crucial to leverage their capabilities and to avoid conflicts with professional relief units. In this paper, we empirically identify key requirements that professional relief units pose on this coordination. Based on these requirements, we suggest a decision model. We computationally solve a real-world instance of the model and empirically validate the computed solution in interviews with practitioners. Our results show that the suggested model allows for solving volunteer coordination tasks of realistic size near-optimally within short time, with the determined solution being well accepted by practitioners. We also describe in this article how the suggested decision support model is integrated in the volunteer coordination system which we develop in joint cooperation with a disaster management authority and a software development company.}}, author = {{Rauchecker, Gerhard and Schryen, Guido}}, booktitle = {{Proceedings of the 15th International Conference on Information Systems for Crisis Response and Management}}, keywords = {{Coordination of spontaneous volunteers, volunteer coordination system, decision support, scheduling optimization model, linear programming}}, location = {{Rochester, NY, USA}}, title = {{{Decision Support for the Optimal Coordination of Spontaneous Volunteers in Disaster Relief}}}, year = {{2018}}, } @inproceedings{5681, author = {{Prester, Julian and Wagner, Gerit and Schryen, Guido}}, booktitle = {{Proceedings of the 2018 International Conference on Information Systems (ICIS 2018)}}, location = {{San Francisco, CA, USA}}, title = {{{Classifying the Ideational Impact of IS Review Articles: A Natural Language Processing Based Approach}}}, year = {{2018}}, }