@proceedings{19974, abstract = {{Due to the trend towards lightweight design in car body development mechanical joining technologies become increasingly important. These techniques allow for the joining of dissimilar materials and thus enable multi-material design, while thermic joining methods reach their limits. Semi-tubular self-piercing riveting is an important mechanical joining technology. The rivet production, however, is costly and time-consuming, as the process consists of several process steps including the heat treatment and coating of the rivets in order to achieve an adequate strength and corrosion resistance. The use of high nitrogen steel as rivet material leads to the possibility of reducing process steps and hence increasing the efficiency of the process. However, the high tool loads being expected due to the high strain hardening of the material are a major challenge during the rivet production. Thus, there is a need for appropriate forming strategies, such as the manufacturing of the rivets at elevated temperatures. Prior investigations led to the conclusion that forming already at 200 °C results in a distinct reduction of the yield strength. To create a deeper understanding of the forming behaviour of high nitrogen steel at elevated temperatures, compression tests were conducted in a temperature range between room temperature and 200 °C. The determined true stress – true strain curves are the basis for the further process and tool design of the rivet production. Another key factor for the rivet manufacturing at elevated temperatures is the influence of the process temperature on the tribological conditions. For this reason, ring compression tests at room temperature and 200 °C are carried out. The friction factors are determined on the basis of calibration curves resulting from the numerical analysis of the ring compression process. The investigations indicate that the friction factor at 200 °C is significantly higher compared to room temperature. This essential fact has to be taken into account for the process and tool design for the rivet production using high nitrogen steel.}}, editor = {{Kuball, Clara-Maria and Jung, R and Uhe, Benedikt and Meschut, Gerson and Merklein, Marion}}, keywords = {{High nitrogen steel, Self-piercing riveting, Joining by forming, Bulk forming, Strain hardening}}, title = {{{Influence of the process temperature on the forming behaviour and the friction during bulk forming of high nitrogen steel}}}, doi = {{10.1016/j.jajp.2020.100023}}, volume = {{1}}, year = {{2020}}, } @phdthesis{15030, abstract = {{Working-media-based forming processes (WMBF) represent a great potential regarding the production of complex sheet-metal lightweight components with excellent surface quality, shape accuracy and dimensional stability. The working-media-based forming processes characterize the sheet-metal forming process, where the sheet metal blank is formed during the forming process by means of a (quasi-)static or dynamic working media pressure into a contouring forming tool. Although the WMBF offers improved utilization of the formability of the used materials compared to conventional sheet metal forming processes, there are limits in the production of complex deeper or sharp edged components with (quasi-)static and dynamic WMBF processes, which can not be overcome by using these methods alone. In order to overcome this, multi-level WMBF process sequences for components with spherical and stepped geometries are developed in this work. Here the developed strategies combine the advantages of (quasi-)static and dynamic WMBF processes. Furthermore, based on analytical, experimental and numerical investigations, innovative process management strategies were derived, which completely compensate the local wall thickness changes, make better use of existing material resources and thus enable the safe production of mentioned geometries.}}, author = {{Djakow, Eugen}}, keywords = {{High Speed Forming}}, pages = {{188}}, publisher = {{Shaker}}, title = {{{Ein Beitrag zur kombinierten (quasi-)statischen und dynamischen Umformung von blechförmigen Halbzeugen}}}, doi = {{ISBN 978-3-8440-6723-1}}, year = {{2019}}, } @inproceedings{17651, abstract = {{Consider mitigating the effects of denial of service or of malicious traffic in networks by deleting edges. Edge deletion reduces the DoS or the number of the malicious flows, but it also inadvertently removes some of the desired flows. To model this important problem, we formulate two problems: (1) remove all the undesirable flows while minimizing the damage to the desirable ones and (2) balance removing the undesirable flows and not removing too many of the desirable flows. We prove these problems are equivalent to important theoretical problems, thereby being important not only practically but also theoretically, and very hard to approximate in a general network. We employ reductions to nonetheless approximate the problem and also provide a greedy approximation. When the network is a tree, the problems are still MAX SNP-hard, but we provide a greedy-based 2l-approximation algorithm, where l is the longest desirable flow. We also provide an algorithm, approximating the first and the second problem within {\$}{\$}2 {\backslash}sqrt{\{} 2{\backslash}left| E {\backslash}right| {\}}{\$}{\$}and {\$}{\$}2 {\backslash}sqrt{\{}2 ({\backslash}left| E {\backslash}right| + {\backslash}left| {\backslash}text {\{}undesirable flows{\}} {\backslash}right| ){\}}{\$}{\$}, respectively, where E is the set of the edges of the network. We also provide a fixed-parameter tractable (FPT) algorithm. Finally, if the tree has a root such that every flow in the tree flows on the path from the root to a leaf, we solve the problem exactly using dynamic programming.}}, author = {{Polevoy, Gleb and Trajanovski, Stojan and Grosso, Paola and de Laat, Cees}}, booktitle = {{Combinatorial Optimization and Applications}}, editor = {{Kim, Donghyun and Uma, R. N. and Zelikovsky, Alexander}}, isbn = {{978-3-030-04651-4}}, keywords = {{flow, Red-Blue Set Cover, Positive-Negative Partial Set Cover, approximation, tree, MAX SNP-hard, root, leaf, dynamic programming, FPT}}, pages = {{217--232}}, publisher = {{Springer International Publishing}}, title = {{{Removing Undesirable Flows by Edge Deletion}}}, 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}}, } @article{10129, abstract = {{There are many hard conjectures in graph theory, like Tutte's 5-flow conjecture, and the 5-cycle double cover conjecture, which would be true in general if they would be true for cubic graphs. Since most of them are trivially true for 3-edge-colorable cubic graphs, cubic graphs which are not 3-edge-colorable, often called snarks, play a key role in this context. Here, we survey parameters measuring how far apart a non 3-edge-colorable graph is from being 3-edge-colorable. We study their interrelation and prove some new results. Besides getting new insight into the structure of snarks, we show that such measures give partial results with respect to these important conjectures. The paper closes with a list of open problems and conjectures.}}, author = {{Fiol, M. A. and Mazzuoccolo, Guiseppe and Steffen, Eckhard}}, journal = {{The Electronic Journal of Combinatorics}}, keywords = {{Cubic graph, Tait coloring, Snark, Boole coloring, Berge's conjecture, Tutte's 5-flow conjecture}}, number = {{4}}, title = {{{Measures of Edge-Uncolorability of Cubic Graphs}}}, volume = {{25}}, year = {{2018}}, } @inproceedings{17652, author = {{Polevoy, Gleb and Trajanovski, Stojan and Grosso, Paola and de Laat, Cees}}, booktitle = {{Combinatorial Optimization and Applications: 11th International Conference, COCOA 2017, Shanghai, China, December 16-18, 2017, Proceedings, Part I}}, isbn = {{978-3-319-71150-8}}, keywords = {{flow, filter, MMSA, set cover, approximation, local ratio algorithm}}, pages = {{3--17}}, publisher = {{Springer International Publishing}}, title = {{{Filtering Undesirable Flows in Networks}}}, doi = {{10.1007/978-3-319-71150-8_1}}, year = {{2017}}, } @article{4873, abstract = {{Banks face a 'behavioralization' of their balance sheets since deposit funding increasingly consists of non-maturing deposits with uncertain cash flows exposing banks to asset liability (ALM) risk. Thus, this study examines the behavior of banks’ retail customers regarding non-maturing deposits. Our unique sample comprises the contract and cash flow data for 2.2 million individual contracts from 1991 to 2010. We find that contractual rewards, i.e., qualified interest payments, and government subsidies, effectively stabilize saving behavior and thus bank funding. The probability of an early deposit withdrawal decreases by approximately 40%, and cash flow volatility drops by about 25%. Our findings provide important insights for banks using pricing incentives to steer desired saving patterns for their non-maturing deposit portfolios. Finally, these results are informative regarding the bank liquidity regulations (Basel III) concerning the stability of deposits and the minimum requirements for risk management (European Commission DIRECTIVE 2006/48/EC). }}, author = {{Schlueter, Tobias and Sievers, Sönke and Hartmann-Wendels, Thomas}}, journal = {{Journal of Banking & Finance (VHB-JOURQUAL 4 Ranking A)}}, keywords = {{retail saving behavior, non-maturing deposits, deposit funding, contractual rewards, interest rate bonus, saving persistence, cash flow volatility}}, pages = {{43--61}}, title = {{{Bank funding stability, pricing strategies and the guidance of depositors}}}, doi = {{10.2139/ssrn.2001449}}, volume = {{51}}, year = {{2015}}, } @article{17663, abstract = {{In this paper, we define and study a new problem, referred to as the Dependent Unsplittable Flow Problem (D-UFP). We present and discuss this problem in the context of large-scale powerful (radar/camera) sensor networks, but we believe it has important applications on the admission of large flows in other networks as well. In order to optimize the selection of flows transmitted to the gateway, D-UFP takes into account possible dependencies between flows. We show that D-UFP is more difficult than NP-hard problems for which no good approximation is known. Then, we address two special cases of this problem: the case where all the sensors have a shared channel and the case where the sensors form a mesh and route to the gateway over a spanning tree.}}, author = {{Cohen, R. and Nudelman, I. and Polevoy, Gleb}}, issn = {{1063-6692}}, journal = {{Networking, IEEE/ACM Transactions on}}, keywords = {{Approximation algorithms, Approximation methods, Bandwidth, Logic gates, Radar, Vectors, Wireless sensor networks, Dependent flow scheduling, sensor networks}}, number = {{5}}, pages = {{1461--1471}}, title = {{{On the Admission of Dependent Flows in Powerful Sensor Networks}}}, doi = {{10.1109/TNET.2012.2227792}}, volume = {{21}}, year = {{2013}}, } @inproceedings{10620, author = {{Anwer, Jahanzeb and Meisner, Sebastian and Platzner, Marco}}, booktitle = {{Reconfigurable Computing and FPGAs (ReConFig), 2013 International Conference on}}, keywords = {{fault tolerant computing, field programmable gate arrays, logic design, reliability, BYU-LANL tool, DRM tool flow, FPGA based hardware designs, avionic application, device technologies, dynamic reliability management, fault-tolerant operation, hardware designs, reconfiguring reliability levels, space applications, Field programmable gate arrays, Hardware, Redundancy, Reliability engineering, Runtime, Tunneling magnetoresistance}}, pages = {{1--6}}, title = {{{Dynamic reliability management: Reconfiguring reliability-levels of hardware designs at runtime}}}, doi = {{10.1109/ReConFig.2013.6732280}}, year = {{2013}}, } @article{5113, abstract = {{Standard equity valuation approaches (i.e., DDM, RIM, and DCF model) are derived under the assumption of ideal conditions, such as infinite payoffs and clean surplus accounting. Because these conditions are hardly ever met, we extend the standard approaches, based on the fundamental principle of financial statement articulation. The extended models are then tested empirically by employing two sets of forecasts: (1) analyst forecasts provided by Value Line and (2) forecasts generated by cross-sectional regression models. The main result is that our extended models yield considerably smaller valuation errors. Moreover, by construction, identical value estimates are obtained across the extended models. By reestablishing empirical equivalence under non-ideal conditions, our approach provides a benchmark that enables us to quantify the errors resulting from individual deviations from ideal conditions, and thus, to analyze the robustness of the standard approaches. Finally, by providing a level playing field for the different valuation approaches, our findings have implications for other empirical settings, for example, estimating the implied cost of capital. }}, author = {{Heinrichs, Nicolas and Hess, Dieter and Homburg, Carsten and Lorenz, Michael and Sievers, Sönke}}, journal = {{Contemporary Accounting Research (VHB-JOURQUAL 4 Ranking A+)}}, keywords = {{Dividend Discount Model, Residual Income, Discounted Cash Flow, Dirty Surplus, Terminal Value, Valuation Error}}, number = {{1}}, pages = {{42--79}}, publisher = {{Wiley Online Library}}, title = {{{Extended dividend, cash flow, and residual income valuation models: Accounting for deviations from ideal conditions}}}, doi = {{10.2139/ssrn.1145201}}, volume = {{30}}, year = {{2013}}, } @inproceedings{37050, abstract = {{The main obstacle for the wide acceptance of UML and SysML in the design of electronic systems is due to a major gap in the design flow between UML-based modeling and SystemC-based verification. To overcome this gap, we present an approach developed in the SATURN project which introduces UML profiles for the co-modeling of SystemC and C with code generation support in the context of the SysML tool suite ARTiSAN Studio®. We finally discuss the evaluation of the approach by two case studies.}}, author = {{Müller, Wolfgang and He, Da and Mischkalla, Fabian and Wegele, Arthur and Larkham, Adrian and Whiston, Paul and Penil, Pablo and Villar, Eugenio and Mitas, Nikolaos and Kritharidis, Dimitros and Azcarate, Florent and Carballeda, Manuel}}, booktitle = {{Proceedings of the IEEE Computer Society Annual Symposium on VLSI}}, keywords = {{Communicate Sequential Process Virtual Platform Smart Camera Synchronous Data Flow Artisan Studio}}, title = {{{The SATURN Approach to SysML-based HW/SW Codesign}}}, doi = {{10.1007/978-94-007-1488-5_9}}, year = {{2010}}, } @article{10646, author = {{Danne, Klaus and Mühlenbernd, Roland and Platzner, Marco}}, issn = {{1751-8601}}, journal = {{IET Computers Digital Techniques}}, keywords = {{reconfigurable architectures, resource allocation, device reconfiguration time, dynamic hardware reconfiguration, dynamically reconfigurable hardware, light-weight runtime system, merge server distribute load, periodic real-time tasks, runtime system overheads, schedulability analysis, scheduling technique, server-based execution, synthesis tool flow}}, number = {{4}}, pages = {{295--302}}, title = {{{Server-based execution of periodic tasks on dynamically reconfigurable hardware}}}, doi = {{10.1049/iet-cdt:20060186}}, volume = {{1}}, year = {{2007}}, } @inproceedings{39538, abstract = {{This article discusses the application of Pictorial Janus (PJ) for the rapid development and analysis of protocols by animation and complete visualization. In order to make PJ applicable in the context of hardware description we first extend PJ by timing facilities (Timed PJ) and introduce an approach for integrating VHDL models into this visual framework preserving the simulation semantics of VHDL. We finally give the example of the specification and animation of a non interlocked protocol.}}, author = {{Müller, Wolfgang and Lehrenfeld, Georg and Tahedl, C.}}, booktitle = {{Proceedings of ASP-DAC'95/CHDL'95/VLSI'95 with EDA Technofair}}, isbn = {{4-930813-67-0}}, keywords = {{Animation, Protocols, Timing, Computer languages, Electronic mail, Context modeling, Visualization, Control systems, Flow graphs, Trademarks}}, title = {{{Complete Visual Specification and Animations of Protocols}}}, doi = {{10.1109/ASPDAC.1995.486383}}, year = {{1995}}, }