@article{SchlosserBoissier2018, author = {Schlosser, Rainer and Boissier, Martin}, title = {Dealing with the dimensionality curse in dynamic pricing competition}, series = {Computers \& Operations Research}, volume = {100}, journal = {Computers \& Operations Research}, publisher = {Elsevier}, address = {Oxford}, issn = {0305-0548}, doi = {10.1016/j.cor.2018.07.011}, pages = {26 -- 42}, year = {2018}, abstract = {Most sales applications are characterized by competition and limited demand information. For successful pricing strategies, frequent price adjustments as well as anticipation of market dynamics are crucial. Both effects are challenging as competitive markets are complex and computations of optimized pricing adjustments can be time-consuming. We analyze stochastic dynamic pricing models under oligopoly competition for the sale of perishable goods. To circumvent the curse of dimensionality, we propose a heuristic approach to efficiently compute price adjustments. To demonstrate our strategy's applicability even if the number of competitors is large and their strategies are unknown, we consider different competitive settings in which competitors frequently and strategically adjust their prices. For all settings, we verify that our heuristic strategy yields promising results. We compare the performance of our heuristic against upper bounds, which are obtained by optimal strategies that take advantage of perfect price anticipations. We find that price adjustment frequencies can have a larger impact on expected profits than price anticipations. Finally, our approach has been applied on Amazon for the sale of used books. We have used a seller's historical market data to calibrate our model. Sales results show that our data-driven strategy outperforms the rule-based strategy of an experienced seller by a profit increase of more than 20\%.}, language = {en} } @misc{CombiOliboniWeskeetal.2018, author = {Combi, Carlo and Oliboni, Barbara and Weske, Mathias and Zerbato, Francesca}, title = {Conceptual modeling of processes and data}, series = {Conceptual Modeling, ER 2018}, volume = {11157}, journal = {Conceptual Modeling, ER 2018}, editor = {Trujillo, JC Davis}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-00847-5}, issn = {0302-9743}, doi = {10.1007/978-3-030-00847-5_18}, pages = {236 -- 250}, year = {2018}, abstract = {Business processes constantly generate, manipulate, and consume data that are managed by organizational databases. Despite being central to process modeling and execution, the link between processes and data is often handled by developers when the process is implemented, thus leaving the connection unexplored during the conceptual design. In this paper, we introduce, formalize, and evaluate a novel conceptual view that bridges the gap between process and data models, and show some kinds of interesting insights that can be derived from this novel proposal.}, language = {en} } @misc{KrentzMeinelGraupner2018, author = {Krentz, Konrad-Felix and Meinel, Christoph and Graupner, Hendrik}, title = {More Lightweight, yet Stronger 802.15.4 Security Through an Intra-layer Optimization}, series = {Foundations and Practice of Security}, volume = {10723}, journal = {Foundations and Practice of Security}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-75650-9}, issn = {0302-9743}, doi = {10.1007/978-3-319-75650-9_12}, pages = {173 -- 188}, year = {2018}, abstract = {802.15.4 security protects against the replay, injection, and eavesdropping of 802.15.4 frames. A core concept of 802.15.4 security is the use of frame counters for both nonce generation and anti-replay protection. While being functional, frame counters (i) cause an increased energy consumption as they incur a per-frame overhead of 4 bytes and (ii) only provide sequential freshness. The Last Bits (LB) optimization does reduce the per-frame overhead of frame counters, yet at the cost of an increased RAM consumption and occasional energy-and time-consuming resynchronization actions. Alternatively, the timeslotted channel hopping (TSCH) media access control (MAC) protocol of 802.15.4 avoids the drawbacks of frame counters by replacing them with timeslot indices, but findings of Yang et al. question the security of TSCH in general. In this paper, we assume the use of ContikiMAC, which is a popular asynchronous MAC protocol for 802.15.4 networks. Under this assumption, we propose an Intra-Layer Optimization for 802.15.4 Security (ILOS), which intertwines 802.15.4 security and ContikiMAC. In effect, ILOS reduces the security-related per-frame overhead even more than the LB optimization, as well as achieves strong freshness. Furthermore, unlike the LB optimization, ILOS neither incurs an increased RAM consumption nor requires resynchronization actions. Beyond that, ILOS integrates with and advances other security supplements to ContikiMAC. We implemented ILOS using OpenMotes and the Contiki operating system.}, language = {en} } @misc{PerscheidFaberKrausetal.2018, author = {Perscheid, Cindy and Faber, Lukas and Kraus, Milena and Arndt, Paul and Janke, Michael and Rehfeldt, Sebastian and Schubotz, Antje and Slosarek, Tamara and Uflacker, Matthias}, title = {A tissue-aware gene selection approach for analyzing multi-tissue gene expression data}, series = {2018 IEEE International Conference on Bioinformatics and Biomedicine (BIBM)}, journal = {2018 IEEE International Conference on Bioinformatics and Biomedicine (BIBM)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-5488-0}, issn = {2156-1125}, doi = {10.1109/BIBM.2018.8621189}, pages = {2159 -- 2166}, year = {2018}, abstract = {High-throughput RNA sequencing (RNAseq) produces large data sets containing expression levels of thousands of genes. The analysis of RNAseq data leads to a better understanding of gene functions and interactions, which eventually helps to study diseases like cancer and develop effective treatments. Large-scale RNAseq expression studies on cancer comprise samples from multiple cancer types and aim to identify their distinct molecular characteristics. Analyzing samples from different cancer types implies analyzing samples from different tissue origin. Such multi-tissue RNAseq data sets require a meaningful analysis that accounts for the inherent tissue-related bias: The identified characteristics must not originate from the differences in tissue types, but from the actual differences in cancer types. However, current analysis procedures do not incorporate that aspect. As a result, we propose to integrate a tissue-awareness into the analysis of multi-tissue RNAseq data. We introduce an extension for gene selection that provides a tissue-wise context for every gene and can be flexibly combined with any existing gene selection approach. We suggest to expand conventional evaluation by additional metrics that are sensitive to the tissue-related bias. Evaluations show that especially low complexity gene selection approaches profit from introducing tissue-awareness.}, language = {en} } @misc{TalaSchrapeKrstićetal.2018, author = {Tala, Mahdi and Schrape, Oliver and Krstić, Miloš and Bertozzi, Davide}, title = {Exploring the Performance-Energy Optimization Space of a Bridge Between 3D-Stacked Electronic and Optical Networks-on-Chip}, series = {XXXIII Conference on Design of Circuits and Integrated Systems (DCIS)}, journal = {XXXIII Conference on Design of Circuits and Integrated Systems (DCIS)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-7281-0171-2}, issn = {2471-6170}, doi = {10.1109/DCIS.2018.8681461}, pages = {6}, year = {2018}, abstract = {The relentless improvement of silicon photonics is making optical interconnects and networks appealing for use in miniaturized systems, where electrical interconnects cannot keep up with the growing levels of core integration due to bandwidth density and power efficiency limitations. At the same time, solutions such as 3D stacking or 2.5D integration open the door to a fully dedicated process optimization for the photonic die. However, an architecture-level integration challenge arises between the electronic network and the optical one in such tightly-integrated parallel systems. It consists of adapting signaling rates, matching the different levels of communication parallelism, handling cross-domain flow control, addressing re-synchronization concerns, and avoiding protocol-dependent deadlock. The associated energy and performance overhead may offset the inherent benefits of the emerging technology itself. This paper explores a hybrid CMOS-ECL bridge architecture between 3D-stacked technology-heterogeneous networks-on-chip (NoCs). The different ways of overcoming the serialization challenge (i.e., through an improvement of the signaling rate and/or through space-/wavelength division multiplexing options) give rise to a configuration space that the paper explores, in search for the most energy-efficient configuration for high-performance.}, language = {en} } @misc{HorowitzFeiRamosetal.2018, author = {Horowitz, Carol R. and Fei, Kezhen and Ramos, Michelle A. and Hauser, Diane and Ellis, Stephen B. and Calman, Neil and B{\"o}ttinger, Erwin}, title = {Receipt of genetic risk information significantly improves blood pressure control among African anecestry adults with hypertension}, series = {Journal of General Internal Medicine}, volume = {33}, journal = {Journal of General Internal Medicine}, publisher = {Springer}, address = {New York}, issn = {0884-8734}, doi = {10.1007/s11606-018-4413-y}, pages = {S322 -- S323}, year = {2018}, language = {en} } @article{ReinRamsonLinckeetal.2017, author = {Rein, Patrick and Ramson, Stefan and Lincke, Jens and Felgentreff, Tim and Hirschfeld, Robert}, title = {Group-Based Behavior Adaptation Mechanisms in Object-Oriented Systems}, series = {IEEE software}, volume = {34}, journal = {IEEE software}, number = {6}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Los Alamitos}, issn = {0740-7459}, doi = {10.1109/MS.2017.4121224}, pages = {78 -- 82}, year = {2017}, abstract = {Dynamic and distributed systems require behavior adaptations for groups of objects. Group-based behavior adaptation mechanisms scope adaptations to objects matching conditions beyond class membership. The specification of groups can be explicit or implicit.}, language = {en} } @article{PerscheidSiegmundTaeumeletal.2017, author = {Perscheid, Michael and Siegmund, Benjamin and Taeumel, Marcel and Hirschfeld, Robert}, title = {Studying the advancement in debugging practice of professional software developers}, series = {Software Quality Journal}, volume = {25}, journal = {Software Quality Journal}, publisher = {Springer}, address = {Dordrecht}, issn = {0963-9314}, doi = {10.1007/s11219-015-9294-2}, pages = {83 -- 110}, year = {2017}, abstract = {In 1997, Henry Lieberman stated that debugging is the dirty little secret of computer science. Since then, several promising debugging technologies have been developed such as back-in-time debuggers and automatic fault localization methods. However, the last study about the state-of-the-art in debugging is still more than 15 years old and so it is not clear whether these new approaches have been applied in practice or not. For that reason, we investigate the current state of debugging in a comprehensive study. First, we review the available literature and learn about current approaches and study results. Second, we observe several professional developers while debugging and interview them about their experiences. Third, we create a questionnaire that serves as the basis for a larger online debugging survey. Based on these results, we present new insights into debugging practice that help to suggest new directions for future research.}, language = {en} } @article{ReinTaeumelHirschfeld2017, author = {Rein, Patrick and Taeumel, Marcel and Hirschfeld, Robert}, title = {Making the domain tangible}, series = {Design Thinking Research}, journal = {Design Thinking Research}, publisher = {Springer}, address = {New York}, isbn = {978-3-319-60967-6}, doi = {10.1007/978-3-319-60967-6_9}, pages = {171 -- 194}, year = {2017}, abstract = {Programmers collaborate continuously with domain experts to explore the problem space and to shape a solution that fits the users' needs. In doing so, all parties develop a shared vocabulary, which is above all a list of named concepts and their relationships to each other. Nowadays, many programmers favor object-oriented programming because it allows them to directly represent real-world concepts and interactions from the vocabulary as code. However, when existing domain data is not yet represented as objects, it becomes a challenge to initially bring existing domain data into object-oriented systems and to keep the source code readable. While source code might be comprehensible to programmers, domain experts can struggle, given their non-programming background. We present a new approach to provide a mapping of existing data sources into the object-oriented programming environment. We support keeping the code of the domain model compact and readable while adding implicit means to access external information as internal domain objects. This should encourage programmers to explore different ways to build the software system quickly. Eventually, our approach fosters communication with the domain experts, especially at the beginning of a project. When the details in the problem space are not yet clear, the source code provides a valuable, tangible communication artifact.}, language = {en} } @misc{GieseHenklerHirsch2017, author = {Giese, Holger and Henkler, Stefan and Hirsch, Martin}, title = {A multi-paradigm approach supporting the modular execution of reconfigurable hybrid systems}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-402896}, pages = {34}, year = {2017}, abstract = {Advanced mechatronic systems have to integrate existing technologies from mechanical, electrical and software engineering. They must be able to adapt their structure and behavior at runtime by reconfiguration to react flexibly to changes in the environment. Therefore, a tight integration of structural and behavioral models of the different domains is required. This integration results in complex reconfigurable hybrid systems, the execution logic of which cannot be addressed directly with existing standard modeling, simulation, and code-generation techniques. We present in this paper how our component-based approach for reconfigurable mechatronic systems, M ECHATRONIC UML, efficiently handles the complex interplay of discrete behavior and continuous behavior in a modular manner. In addition, its extension to even more flexible reconfiguration cases is presented.}, language = {en} }