@article{9808, abstract = {{This study presents the methods employed by a team from the department of Mechatronics and Dynamics at the University of Paderborn, Germany for the 2013 PHM data challenge. The focus of the challenge was on maintenance action recommendation for an industrial machinery based on remote monitoring and diagnosis. Since an ensemble of data driven methods has been considered as the state of the art approach in diagnosis and prognosis, the first approach was to evaluate the performance of an ensemble of data driven methods using the parametric data as input and problems (recommended maintenance action) as the output. Due to close correlation of parametric data of different problems, this approach produced high misclassification rate. Event-based decision trees were then constructed to identify problems associated with particular events. To distinguish between problems associated with events that appeared in multiple problems, support vector machine (SVM) with parameters optimally tuned using particle swarm optimization (PSO) was employed. Parametric data was used as the input to the SVM algorithm and majority voting was employed to determine the final decision for cases with multiple events. A total of 165 SVM models were constructed. This approach improved the overall score from 21 to 48. The method was further enhanced by employing an ensemble of three data driven methods, that is, SVM, random forests (RF) and bagged trees (BT), to build the event based models. With this approach, a score of 51 was obtained . The results demonstrate that the proposed event based method can be effective in maintenance action recommendation based on events codes and parametric data acquired remotely from an industrial equipment.}}, author = {{Kimotho, James Kuria and Sondermann-Wölke, Chritoph and Meyer, Tobias and Sextro, Walter}}, journal = {{International Journal of Prognostics and Health Management}}, keywords = {{maintenance decision, Bagged trees, Decision trees, PSO-SVM, Random forests}}, number = {{2}}, title = {{{Application of Event Based Decision Tree and Ensemble of Data Driven Methods for Maintenance Action Recommendation}}}, volume = {{4}}, year = {{2013}}, } @inproceedings{9858, abstract = {{In this contribution, we introduce a multiobjective optimization used to calculate safe optimal working points for a mechatronic system by including stochastic safety-critical signals in an objective function. Our application example consists of a linear drive for a rail-bound vehicle and an actuation unit. The linear drive's secondary part is fixed; the primary part is vehicle-mounted and can be adjusted vertically to account for deviations of the height of the secondary part. A small air gap between both parts improves efficiency, but increases the risk of a collision between the two parts. Using height data of the secondary part, a trajectory for the vertical adjustment of the primary part is calculated. However, unexpected deviations necessitate a readjustment of the air gap. The probability of such unexpected height deviations can be calculated from the readjustment data. The system is equipped with sensors to measure the air gap. Assuming that the sensor noise is normally distributed, noise characteristics are determined. Using this information and the probability distribution of unexpected height deviations, the probability of a collision is determined.T he sensor noise and the probability of a collision between both parts of the linear drive are included in the dynamical model of the system. Using multiobjective optimization, pareto-optimal working points for the controller of the air gap are obtained. By selecting an appropriate working point, safe operation can be ensured.}}, author = {{Meyer, Tobias and Hölscher, Christina and Menke, Michael and Sextro, Walter and Zimmer, Detmar}}, booktitle = {{Proc. Appl. Math. Mech.}}, pages = {{483--484}}, title = {{{Multiobjective Optimization including Safety of Operation Applied to a Linear Drive System}}}, doi = {{10.1002/pamm.201310234}}, volume = {{13}}, year = {{2013}}, } @inproceedings{9859, abstract = {{Self-optimizing mechatronic systems allow the adaptation of the system's behavior to the current situation. This can be used to actively adapt the behavior to the current degradation state of the system or of some of its components. To this end, the Multi-Level Dependability Concept has been developed. In this contribution, we show how the Multi-Level Dependability Concept has been applied to the active suspension module of an innovative rail-bound vehicle. For this module, the usage of control reconfiguration, which is a novel approach to exploit complex redundancy systems, is required. We show that by combining self-optimization with the possibilities given by control reconfiguration, the dependability of a complex mechatronic system can be greatly improved.}}, author = {{Meyer , Tobias and Henning Keßler, Jan and Sextro, Walter and Trächtler, Ansgar}}, booktitle = {{Proceedings of the Annual Reliability and Maintainability Symposium (RAMS)}}, title = {{{Increasing Intelligent Systems' Reliability by Using Reconfiguration}}}, doi = {{10.1109/RAMS.2013.6517636}}, year = {{2013}}, } @article{9860, abstract = {{Self-optimizing mechatronic systems offer possibilities well beyond those of traditional mechatronic systems. Among these is the adaptation of the system behavior to the current situation. To do so, they are able to choose from different working points, which are pre-calculated using multiobjective optimization and are thus Pareto-optimal with regard to the chosen objective functions. In this contribution, a method is presented that allows to continuously control the system degradation by adapting the behavior of a selfoptimizing system throughout its complete lifetime. The current remaining useful lifetime is estimated and then related to the spent lifetime and the desired useful lifetime. Using this information, a reliability-related objective is prioritized using a closed-loop control, which in turn is used to determine the working point of the self-optimizing system. This way, the desired useful lifetime can be achieved. To exemplify the setup of the controller structure and to demonstrate the adaptation of the system behavior, a dynamic model of a clutch system is used. It can be seen that the closed loop controller is able to correct for external perturbations, such as changed requirements, as well as changed system parameters. This way, the modeled system is able to achieve the desired lifetime reliably.}}, author = {{Meyer, Tobias and Sondermann-Wölke, Christoph and Kimotho, James Kuria and Sextro, Walter}}, journal = {{Chemical Engineering Transactions}}, pages = {{625--630}}, title = {{{Controlling the Remaining Useful Lifetime using Self-Optimization}}}, doi = {{10.3303/CET1333105}}, volume = {{33}}, year = {{2013}}, } @misc{9863, abstract = {{The 9th International Workshop on Piezoelectric Materials and Applications in Actuators (IWPMA 2012) was successfully held on 22–25 April 2012 in Hirosaki, Japan. The general chair was Prof. M.K. Kurosawa from the Tokyo Institute of Technology, Japan. In the past, Korea, Germany, Turkey, China, and USA have hosted the annual conference, but this was the first time for the annual IWPMA conference to be held in Japan. The IWPMA 2012 was organized as a joint symposium with JTTAS Smart Actuator/Sensor Study Committee and ICAT International Actuator Symposium. More than 150 people from the world (12 countries) participated and had fruitful discussions with 138 presentations including 11 invited talks. In addition to piezoelectric materials and piezoelectric actuators, the presentation topics were expanded to include solid-state actuators, energy harvesting, multifunctional materials, and other current important issues. It is our honor to pronounce that the “Sensors and Actuators A” journal has published this special issue on the IWPMA 2012 including the best 25 contributions. This issue covers the functional materials, such as piezoelectric and magnetostrictive materials, and their applications. However, for the innovative devices, various ideas concerning materials, mechanisms, designs, fabrication process, and control-systems are also required to be organically combined. From the view of this concept, we believe the published 25 papers can excite the researcher's intellectual curiosity concerning these issues and can serve as the driving force for further breakthroughs. Please enjoy the latest research results selected by our editor team. Finally, we appreciate all participants in the IWPMA 2012 and the devoted reviewers for the publication. We hope that the papers in this special issue will open up the next researches, which will be presented in the future IWPMA conferences.}}, booktitle = {{Sensors and Actuators A: Physical}}, editor = {{Morita, Takeshi and Hemsel, Tobias and Ijima, T. and Jeong, D. Y. and Kanda, T. and Twiefel, Jens and Uzgur, E. and Lallart, M.}}, location = {{Hirosaki}}, pages = {{1--172}}, publisher = {{Elsevier}}, title = {{{Selected Papers from the 9th International Workshop on Piezoelectric Materials and Applications in Actuators}}}, doi = {{10.1016/j.sna.2013.06.017}}, volume = {{200}}, year = {{2013}}, } @article{9866, abstract = {{The hydrothermal method utilizes a solution-based chemical reaction to synthesize piezoelectric thin films and powders. This method has a number of advantages, such as low-temperature synthesis, and high purity and high quality of the product. In order to promote hydrothermal reactions, we developed an ultrasonic assisted hydrothermal method and confirmed that it produces dense and thick lead--zirconate--titanate (PZT) films. In the hydrothermal method, a crystal growth process follows the nucleation process. In this study, we verified that ultrasonic irradiation is effective for the nucleation process, and there is an optimum irradiation period to obtain thicker PZT films. With this optimization, a 9.2-$\mu$ m-thick PZT polycrystalline film was obtained in a single deposition process. For this film, ultrasonic irradiation was carried out from the beginning of the reaction for 18 h, followed by a 6 h deposition without ultrasonic irradiation. These results indicate that the ultrasonic irradiation mainly promotes the nucleation process.}}, author = {{Ohta, Kanako and Isobe, Gaku and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}}, issn = {{0041-624X}}, journal = {{Ultrasonics}}, keywords = {{Piezoelectric material}}, number = {{4}}, pages = {{837 -- 841}}, title = {{{Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method}}}, doi = {{10.1016/j.ultras.2012.12.003}}, volume = {{53}}, year = {{2013}}, } @inproceedings{517, abstract = {{In the Semantic (Web) Services area, services are considered black boxes with a semantic description of their interfaces as to allow for precise service selection and configuration. The semantic description is usually grounded on domain-specific concepts as modeled in ontologies. This accounts for types used in service signatures, but also predicates occurring in preconditions and effects of services. Ontologies, in particular those enhanced with rules, capture the knowledge of domain experts on properties of and relations between domain concepts. In this paper, we present a verification technique for service compositions which makes use of this domain knowledge. We consider a service composition to be an assembly of services of which we just know signatures, preconditions, and effects. We aim at proving that a composition satisfies a (user-defined) requirement, specified in terms of guaranteed preconditions and required postconditions. As an underlying verification engine we use an SMT solver. To take advantage of the domain knowledge (and often, to enable verification at all), the knowledge is fed into the solver in the form of sorts, uninterpreted functions and in particular assertions as to enhance the solver’s reasoning capabilities. Thereby, we allow for deductions within a domain previously unknown to the solver. We exemplify our technique on a case study from the area of water network optimization software.}}, author = {{Walther, Sven and Wehrheim, Heike}}, booktitle = {{Proceedings of the 18th IEEE International Conference on Engineering of Complex Computer Systems (ICECCS)}}, pages = {{24 -- 32 }}, title = {{{Knowledge-Based Verification of Service Compositions - An SMT approach}}}, doi = {{10.1109/ICECCS.2013.14}}, year = {{2013}}, } @techreport{557, abstract = {{Since the last two decades, the water consumption in Germany is decreasing, which causes the water tanks and pipes in a water supply system to work inefficiently. This paper proposes an approach for a decision support system, which helps to decide how to plan new water tanks and resize existing tanks in water supply systems. The approach uses a combination of network reduction, mathematical optimization and hydraulic simulation. The mathematical optimization model is a nonconvex Mixed Integer Quadratically Constrained Program (MIQCP), which is solved by a piecewise linearization. As this may lead to many binary variables and therefore high computational times, the size of the water supply system model is reduced before building the optimization model. By applying several network reduction techniques there may occur some hydraulic differences between the original network model and the reduced network model. To make sure that the solution obtained in the optimization process is feasible in the original water supply system, the solution is verified by a hydraulic simulation tool.}}, author = {{Hallmann, Corinna}}, publisher = {{Universität Paderborn}}, title = {{{An Approach for a Decision Support Systems to optimize Water Tanks in Water Supply Systems by combining Network Reduction, Optimization and Simulation}}}, year = {{2013}}, } @inproceedings{16594, author = {{Flasskamp, Kathrin and Murphey, Todd and Ober-Blobaum, Sina}}, booktitle = {{2013 European Control Conference (ECC)}}, isbn = {{9783033039629}}, title = {{{Discretized switching time optimization problems}}}, doi = {{10.23919/ecc.2013.6669577}}, year = {{2013}}, } @article{16595, author = {{Flaßkamp, Kathrin and Murphey, Todd and Ober-Blöbaum, Sina}}, issn = {{1617-7061}}, journal = {{PAMM}}, pages = {{401--402}}, title = {{{Optimization for discretized switched systems}}}, doi = {{10.1002/pamm.201310196}}, year = {{2013}}, } @inproceedings{16643, author = {{Ober-Blöbaum, Sina and Seifried, Albert}}, booktitle = {{2013 European Control Conference (ECC)}}, isbn = {{9783033039629}}, title = {{{A multiobjective optimization approach for optimal control problems of mechanical systems with uncertainties}}}, doi = {{10.23919/ecc.2013.6669594}}, year = {{2013}}, } @inbook{16670, author = {{Schütze, Oliver and Witting, Katrin and Ober-Blöbaum, Sina and Dellnitz, Michael}}, booktitle = {{EVOLVE- A Bridge between Probability, Set Oriented Numerics and Evolutionary Computation}}, isbn = {{9783642327254}}, issn = {{1860-949X}}, title = {{{Set Oriented Methods for the Numerical Treatment of Multiobjective Optimization Problems}}}, doi = {{10.1007/978-3-642-32726-1_5}}, year = {{2013}}, } @article{16677, author = {{Witting, Katrin and Ober-Blöbaum, Sina and Dellnitz, Michael}}, issn = {{0925-5001}}, journal = {{Journal of Global Optimization}}, pages = {{331--345}}, title = {{{A variational approach to define robustness for parametric multiobjective optimization problems}}}, doi = {{10.1007/s10898-012-9972-6}}, year = {{2013}}, } @inproceedings{15755, author = {{Busa-Fekete, Robert and Fober, T. and Hüllermeier, Eyke}}, booktitle = {{in Proceedings 23th Workshop Computational Intelligence, Dortmund Germany}}, editor = {{Hoffmann, F. and Hüllermeier, Eyke}}, pages = {{237--246}}, publisher = {{KIT Scientific Publishing}}, title = {{{Preference-based evolutionary optimization using generalized racing algorithms}}}, year = {{2013}}, } @inproceedings{15094, author = {{Böttcher, Stefan and Brandenburg, Marc and Hartel, Rita}}, booktitle = {{WEBIST 2013 - Proceedings of the 9th International Conference on Web Information Systems and Technologies}}, pages = {{137--140}}, publisher = {{SciTePress}}, title = {{{DAG - Index - A Compressed Index for XML Keyword Search}}}, year = {{2013}}, } @book{1626, author = {{Krimphove, Dieter}}, pages = {{266}}, publisher = {{Verlag Kovač}}, title = {{{"Ihr betet an, was ihr nicht kennt" (Jo 4, 22) - Eine neue Sicht auf die Trinität }}}, year = {{2013}}, } @inproceedings{16393, abstract = {{Many 3D scenes (e.g. generated from CAD data) are composed of a multitude of objects that are nested in each other. A showroom, for instance, may contain multiple cars and every car has a gearbox with many gearwheels located inside. Because the objects occlude each other, only few are visible from outside. We present a new technique, Spherical Visibility Sampling (SVS), for real-time 3D rendering of such -- possibly highly complex -- scenes. SVS exploits the occlusion and annotates hierarchically structured objects with directional visibility information in a preprocessing step. For different directions, the directional visibility encodes which objects of a scene's region are visible from the outside of the regions' enclosing bounding sphere. Since there is no need to store a separate view space subdivision as in most techniques based on preprocessed visibility, a small memory footprint is achieved. Using the directional visibility information for an interactive walkthrough, the potentially visible objects can be retrieved very efficiently without the need for further visibility tests. Our evaluation shows that using SVS allows to preprocess complex 3D scenes fast and to visualize them in real time (e.g. a Power Plant model and five animated Boeing 777 models with billions of triangles). Because SVS does not require hardware support for occlusion culling during rendering, it is even applicable for rendering large scenes on mobile devices.}}, author = {{Eikel, Benjamin and Jähn, Claudius and Fischer, Matthias and Meyer auf der Heide, Friedhelm}}, booktitle = {{Computer Graphics Forum}}, issn = {{0167-7055}}, number = {{4}}, pages = {{49--58}}, title = {{{Spherical Visibility Sampling}}}, doi = {{10.1111/cgf.12150}}, volume = {{32}}, year = {{2013}}, } @inbook{16406, abstract = {{In order to evaluate the efficiency of algorithms for real-time 3D rendering, different properties like rendering time, occluded triangles, or image quality, need to be investigated. Since these properties depend on the position of the camera, usually some camera path is chosen, along which the measurements are performed. As those measurements cover only a small part of the scene, this approach hardly allows drawing conclusions regarding the algorithm's properties at arbitrary positions in the scene. The presented method allows the systematic and position-independent evaluation of rendering algorithms. It uses an adaptive sampling approach to approximate the distribution of a property (like rendering time) for all positions in the scene. This approximation can be visualized to produce an intuitive impression of the algorithm's behavior or be statistically analyzed for objectively rating and comparing algorithms. We demonstrate our method by evaluating performance aspects of a known occlusion culling algorithm. }}, author = {{Jähn, Claudius and Eikel, Benjamin and Fischer, Matthias and Petring, Ralf and Meyer auf der Heide, Friedhelm}}, booktitle = {{Advances in Visual Computing}}, isbn = {{9783642419133}}, issn = {{0302-9743}}, title = {{{Evaluation of Rendering Algorithms Using Position-Dependent Scene Properties}}}, doi = {{10.1007/978-3-642-41914-0_12}}, year = {{2013}}, } @inbook{16407, abstract = {{Many virtual 3D scenes, especially those that are large, are not structured evenly. For such heterogeneous data, there is no single algorithm that is able to render every scene type at each position fast and with the same high image quality. For a small set of scenes, this situation can be improved if different rendering algorithms are manually assigned to particular parts of the scene by an experienced user. We introduce the Multi-Algorithm-Rendering method. It automatically deploys different rendering algorithms simultaneously for a broad range of scene types. The method divides the scene into subregions and measures the behavior of different algorithms for each region in a preprocessing step. During runtime, this data is utilized to compute an estimate for the quality and running time of the available rendering algorithms from the observer's point of view. By solving an optimizing problem, the image quality can be optimized by an assignment of algorithms to regions while keeping the frame rate almost constant. }}, author = {{Petring, Ralf and Eikel, Benjamin and Jähn, Claudius and Fischer, Matthias and Meyer auf der Heide, Friedhelm}}, booktitle = {{Advances in Visual Computing}}, isbn = {{9783642419133}}, issn = {{0302-9743}}, title = {{{Real-Time 3D Rendering of Heterogeneous Scenes}}}, doi = {{10.1007/978-3-642-41914-0_44}}, year = {{2013}}, } @inproceedings{29966, author = {{Romaus, Christoph and Wimmelbücker, Dominik and Stille, Karl Stephan Christian and Böcker, Joachim}}, booktitle = {{2013 International Electric Machines & Drives Conference}}, publisher = {{IEEE}}, title = {{{Self-optimization energy management considering stochastic influences for a hybrid energy storage of an electric road vehicle}}}, doi = {{10.1109/iemdc.2013.6556194}}, year = {{2013}}, }