@phdthesis{34167, author = {{Riebler, Heinrich}}, title = {{{Efficient parallel branch-and-bound search on FPGAs using work stealing and instance-specific designs}}}, doi = {{10.17619/UNIPB/1-830}}, year = {{2019}}, } @inproceedings{13904, abstract = {{In this paper, we introduce updatable anonymous credential systems (UACS) and use them to construct a new privacy-preserving incentive system. In a UACS, a user holding a credential certifying some attributes can interact with the corresponding issuer to update his attributes. During this, the issuer knows which update function is run, but does not learn the user's previous attributes. Hence the update process preserves anonymity of the user. One example for a class of update functions are additive updates of integer attributes, where the issuer increments an unknown integer attribute value v by some known value k. This kind of update is motivated by an application of UACS to incentive systems. Users in an incentive system can anonymously accumulate points, e.g. in a shop at checkout, and spend them later, e.g. for a discount.}}, author = {{Blömer, Johannes and Bobolz, Jan and Diemert, Denis Pascal and Eidens, Fabian}}, booktitle = {{Proceedings of the 2019 ACM SIGSAC Conference on Computer and Communications Security - CCS '19}}, location = {{London}}, title = {{{Updatable Anonymous Credentials and Applications to Incentive Systems}}}, doi = {{10.1145/3319535.3354223}}, year = {{2019}}, } @misc{45231, author = {{N., N.}}, title = {{{Conception of a digital Sales Bonus System based on Blockchain Technology}}}, year = {{2019}}, } @inproceedings{2480, abstract = {{Understanding the behavior of the components of service function chains (SFCs) in different load situations is important for efficient and automatic management and orches- tration of services. For this purpose and for practical research in network function virtualization in general, there is a great need for benchmarks and experimental data. In this paper, we describe our experiments for characterizing the relationship between resource demands of virtual network functions (VNFs) and the expected performance of the SFC, considering the individual performance of the VNFs as well as the interdependencies among VNFs within the SFC. We have designed our experiments focusing on video streaming, an important application in this context. We present examples of models for predicting the interdependence between resource demands and performance characteristics of SFCs using support vector regression and polynomial regression models. We also show practical evidence from our experiments that VNFs need to be benchmarked in their final chain setup, rather than individually, to capture important interdependencies that affect their performance. The data gathered from our experiments is publicly available.}}, author = {{Dräxler, Sevil and Peuster, Manuel and Illian, Marvin and Karl, Holger}}, booktitle = {{4th IEEE International Conference on Network Softwarization (NetSoft 2018)}}, location = {{Montreal}}, pages = {{318----322}}, publisher = {{IEEE}}, title = {{{Generating Resource and Performance Models for Service Function Chains: The Video Streaming Case}}}, doi = {{10.1109/NETSOFT.2018.8460029}}, year = {{2018}}, } @inproceedings{2481, abstract = {{Network function virtualization requires scaling and placement, deciding the number and the location of function instances. Current approaches are limited in flexibility and practical applicability. Specifically, we study dynamic, single-step, joint scaling and placement of network services with bidirectional flows traversing Physical or Virtual Network Functions (VNFs) and returning to their sources. We develop models to support stateful components and legacy network functions with fixed locations in these network services as well as the possibility of reusing VNFs across network services. We formalize the problem of jointly scaling and placing such network services as a mixed- integer linear program (MILP). We show that this problem is NP-complete and also present a heuristic algorithm to find good solutions in short time. In an extensive evaluation with realistic scenarios, we investigate the capabilities of the two approaches.}}, author = {{Dräxler, Sevil and Schneider, Stefan Balthasar and Karl, Holger}}, booktitle = {{4th IEEE International Conference on Network Softwarization (NetSoft 2018)}}, location = {{Montreal}}, pages = {{123----131}}, publisher = {{IEEE}}, title = {{{ Scaling and Placing Bidirectional Services with Stateful Virtual and Physical Network Functions}}}, year = {{2018}}, } @techreport{2483, abstract = {{Understanding the behavior of distributed cloud service components in different load situations is important for efficient and automatic management and orchestration of these services. For this purpose and for practical research in distributed cloud computing in general, there is need for benchmarks and experimental data. In this paper, we describe our experiments for characterizing the relationship between resource demands of application components and the expected performance of applica- tions. We present initial results for predicting the interdependence between resource demands and performance characteristics using support vector regression and polynomial regression models. The data gathered from our experiments is publicly available.}}, author = {{Dräxler, Sevil and Peuster, Manuel and Illian, Marvin and Karl, Holger}}, title = {{{Towards Predicting Resource Demands and Performance of Distributed Cloud Services}}}, year = {{2018}}, } @inproceedings{2484, abstract = {{We study the classic bin packing problem in a fully-dynamic setting, where new items can arrive and old items may depart. We want algorithms with low asymptotic competitive ratio while repacking items sparingly between updates. Formally, each item i has a movement cost c_i >= 0, and we want to use alpha * OPT bins and incur a movement cost gamma * c_i, either in the worst case, or in an amortized sense, for alpha, gamma as small as possible. We call gamma the recourse of the algorithm. This is motivated by cloud storage applications, where fully-dynamic bin packing models the problem of data backup to minimize the number of disks used, as well as communication incurred in moving file backups between disks. Since the set of files changes over time, we could recompute a solution periodically from scratch, but this would give a high number of disk rewrites, incurring a high energy cost and possible wear and tear of the disks. In this work, we present optimal tradeoffs between number of bins used and number of items repacked, as well as natural extensions of the latter measure.}}, author = {{Feldkord, Björn and Feldotto, Matthias and Gupta, Anupam and Guruganesh, Guru and Kumar, Amit and Riechers, Sören and Wajc, David}}, booktitle = {{45th International Colloquium on Automata, Languages, and Programming (ICALP 2018)}}, editor = {{Chatzigiannakis, Ioannis and Kaklamanis, Christos and Marx, Dániel and Sannella, Donald}}, isbn = {{978-3-95977-076-7}}, issn = {{1868-8969}}, location = {{Prag}}, pages = {{51:1--51:24}}, publisher = {{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik}}, title = {{{Fully-Dynamic Bin Packing with Little Repacking}}}, doi = {{10.4230/LIPIcs.ICALP.2018.51}}, volume = {{107}}, year = {{2018}}, } @inproceedings{2490, author = {{Szopinski, Daniel and Kundisch, Dennis}}, booktitle = {{2nd Business Model Conference}}, location = {{Florence, Italy}}, title = {{{Business model idea generation: An exploratory study on changing perspectives}}}, year = {{2018}}, } @inproceedings{2491, author = {{Szopinski, Daniel}}, booktitle = {{2nd Business Model Conference}}, location = {{Florence, Italy}}, title = {{{How to teach business model innovation to 300+ students: An experience report}}}, year = {{2018}}, } @misc{2559, author = {{Arendt, Lukas Sebastian}}, title = {{{Datengetriebene Geschäftsmodelle: Ein Literaturüberblick}}}, year = {{2018}}, } @article{2848, author = {{Li, Shouwei and Markarian, Christine and Meyer auf der Heide, Friedhelm}}, journal = {{Algorithmica}}, number = {{5}}, pages = {{1556–1574}}, publisher = {{Springer}}, title = {{{Towards Flexible Demands in Online Leasing Problems. }}}, doi = {{10.1007/s00453-018-0420-y}}, volume = {{80}}, year = {{2018}}, } @inproceedings{2862, author = {{Blömer, Johannes and Eidens, Fabian and Juhnke, Jakob}}, booktitle = {{Topics in Cryptology - {CT-RSA} 2018 - The Cryptographers' Track at the {RSA} Conference 2018, Proceedings}}, isbn = {{9783319769523}}, issn = {{0302-9743}}, location = {{San Francisco, CA, USA}}, pages = {{470--490}}, publisher = {{Springer International Publishing}}, title = {{{Practical, Anonymous, and Publicly Linkable Universally-Composable Reputation Systems}}}, doi = {{10.1007/978-3-319-76953-0_25}}, year = {{2018}}, } @inproceedings{2472, author = {{Auroux, Sébastien and Karl, Holger}}, publisher = {{Proc. of IEEE Wireless Communications and Networking Conference (WCNC)}}, title = {{{Distributed Placement of Virtualized Control Applications in Mobile Backhaul Networks}}}, doi = {{ 10.1109/WCNC.2018.8377335}}, year = {{2018}}, } @inproceedings{2681, author = {{Görzen, Thomas and Laux, Florian}}, booktitle = {{Tagungsband Multikonferenz Wirtschaftsinformatik 2018 (MKWI)}}, location = {{Lüneburg}}, title = {{{Extracting the Wisdom from the Crowd: A Comparison of Approaches to Aggregating Collective Intelligence}}}, year = {{2018}}, } @article{2685, author = {{Blömer, Johannes and Kohn, Kathlén}}, issn = {{2470-6566}}, journal = {{SIAM Journal on Applied Algebra and Geometry.}}, number = {{2}}, pages = {{314--338}}, title = {{{Voronoi Cells of Lattices with Respect to Arbitrary Norms}}}, doi = {{10.1137/17M1132045}}, volume = {{2}}, year = {{2018}}, } @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}}, } @inproceedings{3362, abstract = {{Profiling applications on a heterogeneous compute node is challenging since the way to retrieve data from the resources and interpret them varies between resource types and manufacturers. This holds especially true for measuring the energy consumption. In this paper we present Ampehre, a novel open source measurement framework that allows developers to gather comparable measurements from heterogeneous compute nodes, e.g., nodes comprising CPU, GPU, and FPGA. We explain the architecture of Ampehre and detail the measurement process on the example of energy measurements on CPU and GPU. To characterize the probing effect, we quantitatively analyze the trade-off between the accuracy of measurements and the CPU load imposed by Ampehre. Based on this analysis, we are able to specify reasonable combinations of sampling periods for the different resource types of a compute node.}}, author = {{Lösch, Achim and Wiens, Alex and Platzner, Marco}}, booktitle = {{Proceedings of the International Conference on Architecture of Computing Systems (ARCS)}}, isbn = {{9783319776095}}, issn = {{0302-9743}}, pages = {{73--84}}, publisher = {{Springer International Publishing}}, title = {{{Ampehre: An Open Source Measurement Framework for Heterogeneous Compute Nodes}}}, doi = {{10.1007/978-3-319-77610-1_6}}, volume = {{10793}}, year = {{2018}}, }