TY - CONF AB - Software Quality Lab (s-lab) is an open multi-private-public partnership institute for knowledge and technology transfer. In s-lab, partners from industrial software development closely cooperate with research groups of the University of Paderborn. Together with partners from industry, s-lab develops and evaluates constructive and analytical methods and tools of software engineering for obtaining high-quality software. Testing plays an important role in analytical quality assurance within s-lab’s activities. Thereby our main focus lies on the development of testing methods, test automation tools and test management concepts for the individual needs of the industrial partners. Because of the different requirements of the university and the industry; the cooperation involves some challenges, e.g. defining projects aiming at the commercial interests of the industry and addressing interesting research questions. In this paper, we give an overview of testing activities in s-lab and address targets and challenges of the cooperative work between industry and university. We also summarize the lessons learned during the numerous testing projects especially in the domain of business information systems. AU - Güldali, Baris AU - Sauer, Stefan ID - 8040 T2 - online Proc. of International TestIstanbul Conference 2010 (URL: www.testistanbul.org/presentations.html) TI - Transfer of Testing Research from University to Industry: An Experience Report ER - TY - CONF AU - von der Maßen, Thomas AU - Wübbeke, Andreas ID - 8041 T2 - Proceedings of Software Engineering 2010 (SE2010) TI - Verteiltes Testen heterogener Systemlandschaften VL - P-159 ER - TY - JOUR AU - Valentin, Stefan AU - Karl, Holger ID - 805 IS - 8 JF - European Transactions on Telecommunications TI - Cooperative feedback to improve capacity and error rate in multiuser diversity systems - an OFDM case study ER - TY - JOUR AU - S. Lichte, Hermann AU - Valentin, Stefan AU - Karl, Holger ID - 806 IS - 2 JF - IEEE Communications Letters TI - Expected interference in wireless networks with geometric path loss: a closed-form approximation ER - TY - JOUR AU - Simon Lichte, Hermann AU - Valentin, Stefan AU - Karl, Holger ID - 807 IS - 6 JF - Mobile Networks and Applications TI - Automated Development of Cooperative MAC Protocols - A Compiler-Assisted Approach ER - TY - CONF AU - Andree, Matthias AU - Gebel, Alexander AU - Karl, Holger ID - 808 T2 - 10th IEEE International Conference on Computer and Information Technology, CIT 2010, Bradford, West Yorkshire, UK, June 29-July 1, 2010 TI - Concept and Prototype for a Real-Time Enabled Publish/Subscribe System ER - TY - CONF AU - Birkenheuer, Georg AU - Brinkmann, Andre AU - Karl, Holger ID - 809 T2 - Job Scheduling Strategies for Parallel Processing - 15th International Workshop, JSSPP 2010, Atlanta, GA, USA, April 23, 2010, Revised Selected Papers TI - Risk Aware Overbooking for Commercial Grids ER - TY - CONF AU - S. Lichte, Hermann AU - Frey, Hannes AU - Karl, Holger ID - 810 T2 - Proceedings of the 11th ACM Interational Symposium on Mobile Ad Hoc Networking and Computing, MobiHoc 2010, Chicago, IL, USA, September 20-24, 2010 TI - Fading-resistant low-latency broadcasts in wireless multihop networks: the probabilistic cooperation diversity approach ER - TY - CONF AU - Biermann, Thorsten AU - Dannewitz, Christian AU - Karl, Holger ID - 811 T2 - Testbeds and Research Infrastructures. Development of Networks and Communities - 6th International ICST Conference, TridentCom 2010, Berlin, Germany, May 18-20, 2010, Revised Selected Papers TI - FIT: Future Internet Toolbox ER - TY - CONF AU - Dannewitz, Christian AU - Biermann, Thorsten AU - Dräxler, Martin AU - Beister, Frederic AU - Karl, Holger ID - 812 T2 - Testbeds and Research Infrastructures. Development of Networks and Communities - 6th International ICST Conference, TridentCom 2010, Berlin, Germany, May 18-20, 2010, Revised Selected Papers TI - Prototyping with the Future Internet Toolbox ER - TY - GEN AB - Modern business process modeling environments support distributed development by means of model version control, i.e., comparison and merging of two different model versions. This is a challenging task since most modeling languages support an almost arbitrary creation of process models. Thus, in multi-developer environments, process models or parts of them are often syntactically very different but semantically equivalent. Hence, the comparison of business process models must be performed on a semantic level rather then on a syntactic level. For the domain of business process modeling, this problem is yet unsolved. This paper describes an approach that allows the semantic comparison of different business process models using a normal form. For that purpose, the process models are fully automatically translated into process model terms and normalized using a term rewriting system. The resulting normal forms can be efficiently compared. Our approach enables the semantic comparison of business process models ignoring syntactic redundancies. AU - Gerth, Christian AU - Luckey, Markus AU - Küster, Jochen AU - Engels, Gregor ID - 8219 TI - Detection of Semantically Equivalent Fragments for Business Process Model Change Management ER - TY - GEN AU - Hülsbusch, Mathias AU - König, Barbara AU - Rensink, Arend AU - Semenyak, Maria AU - Soltenborn, Christian AU - Wehrheim, Heike ID - 8220 TI - Full Semantics Preservation in Model Transformation - A Comparison of Proof Techniques ER - TY - CONF AB - In double-sided markets for computing resources an optimal allocation schedule among job offers and requests subject to relevant capacity constraints can be determined. With increasing storage demands and emerging storage services the question how to schedule storage jobs becomes more and more interesting. Since such scheduling problems are often in the class NP-complete an exact computation is not feasible in practice. On the other hand an approximation to the optimal solution can easily be found by means of using heuristics. The problem with this attempt is that the suggested solution may not be exactly optimal and is thus less satisfying. Considering the two above mentioned solution approaches one can clearly find a trade-off between the optimality of the solution and the efficiency to get to a solution at all. This work proposes to apply and combine heuristics in optimization to gain from both of their benefits while reducing the problematic aspects. Following this method it is assumed to get closer to the optimal solution in a shorter time compared to a full optimization. AU - Finkbeiner, Josef AU - Bodenstein, Christian AU - Schryen, Guido AU - Neumann, Dirk ID - 5685 KW - Decision Support System KW - Algorithms KW - Optimization KW - Market Engineering T2 - 18th European Conference on Information Systems (ECIS 2010) TI - Applying heuristic methods for job scheduling in storage markets ER - TY - CONF AB - In a world, where more and more businesses seem to trade in an online market, the supply of online services to supply the ever-growing demand could quickly reach its capacity limits. Online service providers may find themselves maxed out at peak operation levels during high-traffic timeslots but too little demand during low-traffic timeslots, although the latter is becoming less frequent. At this point not only deciding which user is allocated what level of service becomes essential, but also the magnitude of the service provided, can be controlled by pricing. Pricing is an important factor when efficient and acceptable allocation of resources between individuals must be reached. Without prices, transferring or sharing goods would be impossible. In sharing information, pricing a product however is not as simple as relatively pricing an apple or a pear. Often the costs, and hence the prices are simply unknown. Backed by this scenario, the online services market could be combined with the market design mechanism of diamonds. For this we propose an ultimatum pricing strategy which effectively allows for valuations to be accounted for, but no longer a necessity when pricing in grid, cloud or other online computing environments. AU - Bodenstein, Christian AU - Schryen, Guido AU - Neumann, Dirk ID - 5690 KW - Posted Price KW - Ultimatum Game KW - Energy Efficiency KW - Mechanism Design T2 - 18th European Conference on Information Systems (ECIS 2010) TI - From "Take-it-or-leave-it" offers to "Take-it-or-be-left-out" Ultimatum - A trade mechanism for Online Services ER - TY - BOOK ED - Ackermann, Sebastian ED - Wünderlich, Nancy ED - Wangenheim, Florian v. ID - 5720 SN - 9783842301511 TI - Geschäftsmodelle in virtuellen Spielwelten ER - TY - CONF AU - Brüseke, Frank AU - Sancar, Yavuz AU - Yigitbas, Enes ID - 5756 T2 - Proceedings of the Conference on Software & Systems Engineering Essentials 2010 (SEE 2010), Köln (Germany) TI - Erfolgsfaktoren von Testprozessbewertungsmodellen ER - TY - GEN AU - Kabst, Rüdiger ID - 6109 TI - Editorial: Aufschwung mitgestalten VL - 2 ER - TY - GEN AU - Kabst, Rüdiger AU - Kötter, P M AU - Meifert, M AU - Wehner, M C ID - 6110 TI - HR Business Partner gesucht VL - 3 ER - TY - GEN AU - Kabst, Rüdiger ID - 6112 TI - Editorial: Verdrängte Herausforderung Demographie VL - 6 ER - TY - GEN AU - Kabst, Rüdiger AU - Baum, M AU - Fortange, A ID - 6113 TI - Was High-Performer besser machen: Was unterscheidet erfolgreiche von weniger erfolgreichen Unternehmen beim Employer Branding? VL - 10 ER - TY - BOOK AU - Kabst, Rüdiger ID - 6139 SN - 3-942-54302-8 TI - Interim Management: Auf dem Weg zur Selbstverständlichkeit ER - TY - CHAP AU - Isidor, R AU - Schwens, C AU - Kabst, Rüdiger ED - Schmid, S ID - 6150 T2 - Internationale Unternehmungen und das Management ausländischer Tochtergesellschaften TI - A Conceptual Framework for the International Staffing of Early Internationalizers ER - TY - CHAP AU - Schwens, C AU - Steinmetz, Holger AU - Kabst, Rüdiger ED - Gerybadze, A ED - Hommel, U ED - Reiner, H W ED - Thomaschweski, D ID - 6154 T2 - Innovation and International Corporate Growth TI - Growth and Internationalization of Renewable Energy and New Technology-Based Firms ER - TY - CHAP AU - Kabst, Rüdiger AU - Wehner, M C ED - Meifert, M ID - 6155 T2 - Strategische Personalentwicklung TI - Institutionalisierung der Personalentwicklung: Ist der Patient auf dem Weg der Besserung? ER - TY - CHAP AU - Kabst, Rüdiger AU - Wehner, M C ED - Schwuchow, K ED - Gutmann, J ID - 6157 T2 - Jahrbuch Personalentwicklung 2010 TI - Personalmanagement der Zukunft: Quo Vadis? ER - TY - CHAP AU - Eberl, P AU - Kabst, R ED - Sydow, J ID - 6159 T2 - Management von Netzwerkorganisationen TI - Vertrauen, Opportunismus, Kontrolle: Eine empirische Analyse von Joint Venture Beziehungen vor dem Hintergrund der Transaktionskostentheorie. ER - TY - JOUR AU - Kabst, Rüdiger AU - Isidor, R AU - Steinmetz, Holger AU - Schwens, C ID - 6230 IS - 3 JF - Management Revue: The International Review of Management Studies. TI - Enlarging the focus on the role of competencies, abilities, and personality in management research. VL - 21 ER - TY - GEN AU - Wolf, S AU - Weißenberger, B E AU - Barbara, E AU - Kabst, Rüdiger AU - Wehner, M ID - 6235 TI - Management accountants as business partners: An empirical analysis based on the theory of reasoned action ER - TY - CONF AU - Baum, M AU - Schwens, C AU - Kabst, Rüdiger ID - 6306 TI - Are networks always beneficial? An empirical analysis on the relationship between knowledge intensity and international new venturing ER - TY - CONF AU - Haus, I AU - Steinmetz, Holger AU - Isidor, R AU - Kabst, Rüdiger ID - 6309 TI - Der Einfluss des Geschlechts auf die Gründungsintention – Ein meta-analytisches Pfadmodell (The influence of gender on entrepreneurial intention – a meta-analytical path model) ER - TY - CONF AU - Baum, M AU - Schwens, C AU - Kabst, Rüdiger ID - 6315 TI - Different types of international new ventures: A latent class analysis ER - TY - CONF AU - Baum, M AU - Schwens, C AU - Kabst, Rüdiger ID - 6318 TI - The different types of international new ventures: A latent class analysis ER - TY - CONF AU - Baum, M AU - Kabst, Rüdiger ID - 6321 TI - The impact of employer awards on employer knowledge and applicant attraction: The moderating influence of corporate brand awareness ER - TY - JOUR AB - Die aktuelle hochschuldidaktische Diskussion ist durch Schlüsselbegriffe wie Outcome- und Kompetenzorientierung geprägt. Allerdings sind die Strategien zur nachhaltigen Gestaltung der Lehr- und Lernpraxis bisher nur wenig differenziert. Der Beitrag stellt das Konzept einer "institutionsweiten Hochschulentwicklung" vor. Dieses spricht individuelles Handeln von Lehrenden und Lernenden sowie curriculare und organisationale Aspekte an. Mittels Experteninterviews wird gezeigt, dass Hochschulentwicklung eine "Third-Space-Funktion" zwischen Akademie und Administration einnimmt. Das personelle Profil solcher Einrichtungen verlangt nach "Blended Professionals", die sowohl als Servicepersonal als auch als Mitglieder der akademischen Welt wirkungsvoll agieren können. AU - Jenert, Tobias AU - Brahm, Taiga ID - 4433 IS - 4 JF - Zeitschrift für Hochschulentwicklung KW - Hochschulentwicklung KW - educational development KW - higher education KW - Hochschuldidaktik TI - ,,Blended Professionals´´ als Akteure einer institutionsweiten Hochschulentwicklung VL - 5 ER - TY - GEN AB - "Lernkultur" wird als Begriff häufig gebraucht und fast ebenso häufig definiert  das gilt für den betrieblichen Kontext ebenso wie für die Bereiche der Schul-, Hochschul-, Berufs- und Erwachsenenbildung (z. B. Wulf, Althans, Blaschke, Ferrin, Göhlich, Jörissen, Mattig et al., 2007; Jenert, Zellweger Moser, Dommen & Gebhardt, 2009; Kirchhöfer, 2004; Erpenbeck & Sauer, 2000). Trotz der grossen Aufmerksamkeit, die der Begriff in den letzten zwei Jahrzehnten erfahren hat, kann man nicht von einem in sich geschlossenen Forschungsprogramm sprechen. Die Zugänge zum Phänomenbereich Lernkultur sind ebenso vielfältig wie die hinter einzelnen Ansätzen stehenden Lernkulturkonstrukte. Den Autoren ist keine Publikation bekannt, welche unterschiedliche Ansätze der Lernkulturforschung systematisch aufarbeitet. Eine wichtige Referenzquelle ist der Bericht von Kuh und Whitt (1988) "The Invisible Tapestry: Culture in American Colleges and Universities". Ausgehend von einer fundierten Übersicht zu unterschiedlichen Zugängen zum Kulturbegriff (oft in starker Anlehnung an die Organisationskulturforschung (vgl. Allaire & Firsirotu, 1984)) stellen die Autoren ein Rahmenmodell zur Analyse von Hochschulkulturen vor (Kuh und Whitt, 1988, S. 56). Diese Arbeit erweist sich für ein besseres Verständnis unter-schiedlicher Zugänge zum Lernkulturbegriff als aufschlussreich, weil im Kontext Hoch-schule zwangsweise viele Aspekte des Lernens und Lehrens angesprochen werden. Allerdings fokussiert auch dieser Bericht nicht das Konstrukt der Lernkultur und bietet damit nur einen Ausgangspunkt für die Identifizierung unterschiedlicher Zugänge. AU - Jenert, Tobias AU - Gebhardt, Anja ID - 4448 KW - Lernkultur KW - learning culture KW - culture theory KW - approaches to learning culture KW - culture of learning TI - Zugänge zum Begriff der Lernkultur: Eine Systematisierung auf Basis kultur-und lerntheoretischer Überlegungen ER - TY - GEN AU - Brahm, Taiga AU - Jenert, Tobias AU - Meier, Christoph ID - 4449 KW - Lernkultur KW - Hochschulentwickung KW - Hochschuldidaktik KW - Hochschullehre KW - HEI development TI - Hochschulentwicklung als Gestaltung von Lehr-und Lernkultur: eine institutionsweite Herangehensweise an lehrbezogene Veränderungsprojekte an Hochschulen ER - TY - CONF AU - Jenert, Tobias AU - Gebhardt, Anja ID - 4493 KW - earning culture KW - Lernkultur KW - whole-institution approach KW - higher education KW - Hochschule TI - Learning Cultures at Higher Education Institutions: Outlining a wohle-institution approach to teaching and learning ER - TY - CHAP AU - Jenert, Tobias ID - 4525 T2 - Beyond Knowledge Management TI - Cultural Explorations: How Socio-material Contexts Influence Knowledge Interaction ER - TY - JOUR AB - A fluorescence study of acetonitrile solutions of bis(tetramethylguanidine)propane, copper(I)-iodide and [Cu(btmgp)I] was performed and the chemical reaction of the latter species with O2 was investigated at room temperature. The actual quenching process via O2 gassing was studied and an exponential dependence of the fluorescence intensity with respect to the complex concentration was observed. Furthermore the survey was deepened on time resolved fluorescence properties of solved [Cu(btmgp)I] in a wider concentration range. The applicability of this complex for O2 sensing inside a microreactor system was proven by confocal fluorescence measurements. It was shown that the investigated system can be used for oxygen sensing in the copper concentration range from 10−2 to 10−9 mol/l. AU - Herres-Pawlis, Sonja AU - Berth, Gerhard AU - Wiedemeier, Volker AU - Schmidt, Ludger AU - Zrenner, Artur AU - Warnecke, Hans-Joachim ID - 4548 IS - 10 JF - Journal of Luminescence KW - Copper Oxygen Fluorescence quenching N donor ligands SN - 0022-2313 TI - Oxygen sensing by fluorescence quenching of [Cu(btmgp)I] VL - 130 ER - TY - JOUR AB - Damage caused by laser irradiation on the surface of ZnTe epilayers was studied by micro-Raman and atomic force microscopy (AFM). ZnTe LO-phonon overtones up to four order and TO + (n − 1)LO zone-center phonons were observed in the resonant micro-Raman spectra at room temperature. Discrepancies in the literature regarding the origin of two features observed at low frequencies around 120 and 140 cm−1 in the Raman spectrum of ZnTe are discussed and resolved. These Raman peaks were not detected by using a low excitation laser power density on a Zn-terminated ZnTe surface; however, with the increase of the laser power density they were found to arise irreversibly. The correspondence of these peaks in a wave number with the strongest Raman peaks of the crystalline tellurium phase and the intensity enhancement behavior with the laser power in a similar way as for CdTe strongly suggests the formation of crystalline tellurium aggregates on the layer surface due to laser irradiation damage. AFM data reveal the occurrence of laser ablation on the ZnTe surface even though the surface temperature of the sample is below the melting point. AU - Larramendi, E M AU - Berth, Gerhard AU - Wiedemeier, V AU - Hüsch, K-P AU - Zrenner, Artur AU - Woggon, U AU - Tschumak, E AU - Lischka, K AU - Schikora, D ID - 4549 IS - 7 JF - Semiconductor Science and Technology SN - 0268-1242 TI - Intensity enhancement of Te Raman modes by laser damage in ZnTe epilayers VL - 25 ER - TY - JOUR AB - We have integrated individual (In,Ga)As quantum dots (QDs) using site-controlled molecular beam epitaxial growth into the intrinsic region of a p-i-n junction diode. This is achieved using an in situ combination of focused ion beam prepatterning, annealing, and overgrowth, resulting in arrays of individually electrically addressable (In,Ga)As QDs with full control on the lateral position. Using microelectroluminescence spectroscopy we demonstrate that these QDs have the same optical quality as optically pumped Stranski–Krastanov QDs with random nucleation located in proximity to a doped interface. The results suggest that this technique is scalable and highly interesting for different applications in quantum devices. AU - Mehta, M. AU - Reuter, Dirk AU - Wieck, A. D. AU - Michaelis de Vasconcellos, S. AU - Zrenner, Artur AU - Meier, Cedrik ID - 4550 IS - 14 JF - Applied Physics Letters SN - 0003-6951 TI - An intentionally positioned (In,Ga)As quantum dot in a micron sized light emitting diode VL - 97 ER - TY - JOUR AB - An intentional positioning of optically active quantum dots using site-selective growth by a combination of molecular beam epitaxy (MBE) and focused ion beam (FIB) implantation in an all-ultra-high-vacuum (UHV) setup has been successfully demonstrated. A square array of periodic holes on GaAs substrate was fabricated with FIB of 30 keV ions followed by an in situ annealing step. Subsequently, the patterned holes were overgrown with an optimized amount of InAs in order to achieve site-selective growth of the QDs on the patterned holes. Under well-optimized conditions, a selectivity of single quantum dot growth in the patterned holes of 52% was achieved. Thereafter, carrier injection and subsequent radiative recombination from the positioned InAs/GaAs self-assembled QDs was investigated by embedding the QDs in the intrinsic part of a GaAs-based p–i–n junction device. Electroluminescence spectra taken at 77 K show interband transitions up to the fifth excited state from the QDs. AU - Mehta, Minisha AU - Reuter, Dirk AU - Melnikov, Alexander AU - Wieck, Andreas D. AU - Michaelis de Vasconcellos, Steffen AU - Baumgarten, Tim AU - Zrenner, Artur AU - Meier, Cedrik ID - 4551 IS - 10 JF - Physica E: Low-dimensional Systems and Nanostructures KW - Molecular beam epitaxy KW - Focused ion beam KW - Self-assembled quantum dot KW - Electroluminescence SN - 1386-9477 TI - Intentionally positioned self-assembled InAs quantum dots in an electroluminescent p–i–n junction diode VL - 42 ER - TY - JOUR AB - Here we report on investigations on CdSe quantum dots incorporated in ZnSe based Schottky photodiodes with near-field shadow masks. Photoluminescence and photocurrent of individual quantum dots were studied as a function of the applied bias voltage. The exciton energy of the quantum dot ground state transition was shifted to the excitation energy by using the Stark effect tuning via an external bias voltage. Under the condition of resonance with the laser excitation energy we observed a resonant photocurrent signal due to the tunnelling of carriers out of the quantum dots at electric fields above 500 kV/cm. AU - Panfilova, M. AU - Michaelis de Vasconcellos, S. AU - Pawlis, A. AU - Lischka, K. AU - Zrenner, Artur ID - 4552 IS - 10 JF - Physica E: Low-dimensional Systems and Nanostructures KW - CdSe/ZnSe quantum dots KW - Photodiode KW - Quantum confined Stark Effect KW - Photocurrent KW - II–VI Semiconductors SN - 1386-9477 TI - Resonant photocurrent-spectroscopy of individual CdSe quantum dots VL - 42 ER - TY - JOUR AU - Liu, Xiaohong AU - Grant, David B. AU - McKinnon, Alan C. AU - Feng, Yuanhua ID - 4606 IS - 10 JF - International Journal of Physical Distribution & Logistics Management SN - 0960-0035 TI - An empirical examination of the contribution of capabilities to the competitiveness of logistics service providers VL - 40 ER - TY - JOUR AU - Liu, Xiaohong AU - McKinnon, Alan C. AU - Grant, David B. AU - Feng, Yuanhua ID - 4607 IS - 1 JF - Logistics Research SN - 1865-035X TI - Sources of competitiveness for logistics service providers: a UK industry perspective VL - 2 ER - TY - JOUR AU - Eggert, Andreas AU - Ulaga, Wolfgang ID - 4858 IS - 8 JF - Industrial Marketing Management TI - Managing customer share in key supplier relationships ER - TY - JOUR AU - Wagner, Stephan M AU - Eggert, Andreas AU - Lindemann, Eckhard ID - 4859 IS - 8 JF - Journal of business research TI - Creating and appropriating value in collaborative relationships ER - TY - CHAP AU - Eggert, Andreas AU - Garnefeld, Ina ID - 4960 SN - 978-3-8349-1413-2 T2 - Handbuch Kundenbindungsmanagement TI - Kundenbindung auf Basis des Relationship Value ER - TY - JOUR AU - Thommes, Kirsten AU - Weiland, Katrin ID - 4974 IS - 1 JF - European Management Journal TI - Explanatory factors for firms’ use of temporary agency work in Germany ER - TY - BOOK ED - Kremer, H.-Hugo ED - Zoyke, A. ID - 7001 TI - Individuelle Förderung in der beruflichen Bildung. Grundlegung und Annäherung im Kontext von Forschungs- und Entwicklungsprojekten ER - TY - CONF AU - Ishikawa, Atsushi AU - Oulton, Rupert F. AU - Zentgraf, Thomas AU - Zhang, Xiang ED - Stockman, Mark I. ID - 7251 T2 - Plasmonics: Metallic Nanostructures and Their Optical Properties VIII TI - Extremely low-loss slow-light modes in plasmonic dielectric hybrid systems ER - TY - CONF AU - Sorger, Volker J. AU - Oulton, Rupert F. AU - Zentgraf, Thomas AU - Ma, Renmin AU - Gladden, Christopher AU - Dai, Lun AU - Bartal, Guy AU - Zhang, Xiang ED - Stockman, Mark I. ID - 7252 T2 - Plasmonics: Metallic Nanostructures and Their Optical Properties VIII TI - Semiconductor plasmon laser ER - TY - JOUR AU - Kremer, H.-Hugo ID - 7350 IS - 18 JF - bwp@ Berufs- und Wirtschaftspädagogik - online TI - Individuelle Bildungsgänge im Berufsbildungssystem ER - TY - JOUR AU - Löffler, Renate AU - Güldali, Baris AU - Geisen, Silke ID - 7356 IS - 3 JF - Softwaretechnik-Trends TI - Towards Model-based Acceptance Testing for Scrum VL - 30 ER - TY - JOUR AU - Güldali, Baris AU - Jungmayr, Stefan AU - Mlynarski, Michael AU - Neumann, Stefan AU - Winter, Mario ID - 7357 IS - 3 JF - OBJEKTspektrum TI - Starthilfe für modellbasiertes Testen ER - TY - JOUR AU - Beulen, Dominik AU - Güldali, Baris AU - Mlynarski, Michael ID - 7358 IS - 2 JF - Softwaretechnik-Trends TI - Tabellarischer Vergleich der Prozessmodelle für modellbasiertes Testen aus Managementsicht VL - 30 ER - TY - JOUR AU - Späth, Melanie AU - Mlynarski, Michael ID - 7359 JF - Softwaretechnik-Trends TI - Agiles Testen in Großprojekten mit TDD und Testaspekten: Beobachtungen und erste Erfahrungen VL - 30 ER - TY - JOUR AB - In the last years the software engineering community pays a strong interest in agile development methods. Those methods place software testing for example the Test-Driven Development method as an important task of the development process. Agile projects rely on good test automation tools. In this paper we evaluate five test automation tools for their usage in acceptance testing for web applications using Test-Driven Development. AU - Jureczko, Marian AU - Mlynarski, Michael ID - 7364 JF - Electrical Review TI - Automated acceptance testing tools for web applications using Test-Driven Development VL - 86 ER - TY - CHAP AU - Frehe, Petra AU - Kremer, H.-Hugo ED - Tramm, T. ED - Seeber, S. ED - Kremer, H.-H. ID - 7474 T2 - Funktionen und Erträge pädagogischer Diagnostik im wirtschafts- und berufspädagogischen Bereich TI - Rollenbasierte Kompetenzbilanz - Potenziale und Herausforderungen für das berufsschulische Übergangssystem VL - 22 ER - TY - JOUR AU - Mehta, M. AU - Meier, Cedrik ID - 7494 IS - 2 JF - Journal of The Electrochemical Society SN - 0013-4651 TI - Controlled Etching Behavior of O-Polar and Zn-Polar ZnO Single Crystals VL - 158 ER - TY - JOUR AU - Theis, Jens AU - Geller, Martin AU - Lorke, Axel AU - Wiggers, Hartmut AU - Wieck, Andreas AU - Meier, Cedrik ID - 7496 IS - 45 JF - Nanotechnology SN - 0957-4484 TI - Electroluminescence from silicon nanoparticles fabricated from the gas phase VL - 21 ER - TY - CHAP AU - Oster, Sebastian AU - Wübbeke, Andreas AU - Engels, Gregor AU - Schürr, Andy ED - Mosterman, I. Schieferdecker, J. Zander , P. ID - 7556 T2 - Model-Based Testing For Embedded Systems TI - Model-Based Software Product Lines Testing Survey ER - TY - THES AB - Software Product Lines (SPL) are a development paradigm allowing the reduction of the software system development time while increasing their quality. To reach these goals, the artefacts being part of many or all software systems are developed only once and reused within the different software systems. The software systems developed by a software product line approach are called products. Like a thread the reuse of artefacts is woven into the software product line development process. As some artefacts are only used for the development of some products, these artefacts constitute the variability of the SPL. First of all, the modelling of variability has to be enabled in every artefact. Beside this, dependencies can arise between variable artefacts. The modelling of variability and dependencies also demands the redevelopment or adaption of specification techniques for these artefacts. This thesis focuses on the variability management concerning requirements and test case specification for Software Product Lines. For this purpose, existing modelling languages and specification techniques are augmented with variability instead of redeveloping similar software development artefacts over and over again. In order to augment the modelling languages by variability, a language construction process based on a meta model of the variability management is defined. In order to manage the dependencies between variable artefacts, a feature based variability management is introduced. Finally, the extension of specification techniques for requirements specifications based on use case descriptions and test specifications are described. The contribution of this thesis is substantiated by a prototypical tool support and an industrial case study. AU - Wübbeke, Andreas ID - 7573 TI - Variabilitätsmanagement in Anforderungs- und Testfallspezifikation für Software-Produktlinien ER - TY - CONF AB - Deriving a new language L_B from an already existing one L_A is a typical task in domain-specific language engineering. Here, besides adjusting L_A's syntax, the language engineer has to modify the semantics of L_A to derive L_B's semantics. Particularly, in case of behavioral modeling languages, this is a difficult and error-prone task, as changing the behavior of language elements or adding behavior for new elements might have undesired side effects. Therefore, we propose a test-driven language derivation process. In a first step, the language engineer creates example models containing the changed or newly added elements in different contexts. For each of these models, the language engineer also precisely describes the expected behavior. In a second step, each example model and its description of behavior is transformed into an executable test case. Finally, these test cases are used when deriving the actual semantics of L_B - at any time, the language engineer can run the tests to verify whether the changes he performed on L_A's semantics indeed produce the desired behavior. In this paper, we illustrate the approach using our graph transformation-based semantics specification technique Dynamic Meta Modeling. This is once more an example where the graph transformation approach shows its strengths and appropriateness to support software engineering tasks as, e.g., model transformations, software specifications, or tool development. AU - Engels, Gregor AU - Soltenborn, Christian ID - 8437 T2 - Proceedings of the International Colloquium on Graph and Model Transformation (GraMoT 2010), Berlin (Germany) TI - Test-driven Language Derivation with Graph Transformation-based Dynamic Meta Modeling VL - 30 ER - TY - CONF AU - Güldali, Baris AU - Mlynarski, Michael ID - 8438 T2 - Proceedings of the IWK2010 Workshops: The First International Workshop on Evolution Support for Model-Based Development and Testing (EMDT2010) TI - Agility vs. Model-based Testing: A fair Play? VL - 646 ER - TY - CONF AU - Wübbeke, Andreas AU - Oster, Sebastian ID - 8439 T2 - Proceedings of Produktlinien im Kontext (PIK2010) TI - Verknüpfung von kombinatorischem Plattform- und individuellem Produkt-Test für Software-Produktlinien ER - TY - CONF AU - Sancar, Yavuz AU - Brüseke, Frank AU - Voigt, Hendrik AU - Sauer, Stefan AU - Engels, Gregor ID - 8440 T2 - ECOOP 2010 - Workshop on Testing Object-Oriented Software Systems (ETOOS) TI - Towards Economical Software Release Recommendations ER - TY - CONF AU - Gerth, Christian ID - 8441 T2 - Proceedings of the Joint Workshop of the German Research Training Groups in Computer Science TI - A Framework for Change Management of Business Process Models ER - TY - CONF AU - Luckey, Markus AU - Baumann, Andrea AU - Méndez Fernández, Daniel AU - Wagner, Stefan ID - 8442 T2 - Software Engineering for Secure Systems, 2010. SESS '10. ICSE Workshop TI - Reusing Security Requirements using an Extended Quality Model ER - TY - CONF AU - Sancar, Yavuz AU - Brüseke, Frank AU - Engels, Gregor ID - 8443 T2 - Proceedings of Software-Qualitätsmodellierung und -bewertung (SQMB '10), Paderborn, Germany TI - Teststufenspezifische Qualitätsattribute für die Qualitätsbewertung von nichtfunktionalen Anforderungen ER - TY - CONF AB - To be successful with global software development (GSD), development knowledge needs to be shared among the developers and stakeholders, and the quality of the exchanged information must be assured. Therefore, mature processes, methods and tools have to be in place. If a unified and integrated solution does not exist, this impedes the exchange of knowledge (and the migration of people between projects). In GSD, such a diversity can lead to new problems: offshore development teams have to repeatedly re-adjust to method variants used by the respective business units. This can lead to misinterpretation of information and risks for project success. We report on re-aligning the varying software engineering methods and unifying the methodology throughout Capgemini sd&m. We also standardized quality assurance procedures and tightly integrated them with the engineering methodology. By this, we arrived at a comprehensive company-wide Enterprise Software Engineering Model that effectively supports knowledge transfer from clients to the onshore and offshore team. AU - Salger, Frank AU - Sauer, Stefan AU - Engels, Gregor AU - Baumann, Andrea ID - 8444 T2 - 5th IEEE International Conference on Global Software Engineering (ICGSE 2010) TI - Knowledge Transfer in Global Software Development - Leveraging Ontologies, Tools and Assessments ER - TY - CONF AU - Van den Bergh, Jan AU - Meixner, Gerrit AU - Sauer, Stefan ID - 8445 T2 - Proc. 5th Intl. Workshop on Model Driven Development of Advanced User Interfaces (MDDAUI 2010) TI - MDDAUI 2010 Workshop Report VL - 617 ER - TY - CONF AU - Güldali, Baris AU - Sauer, Stefan AU - Winkelhane, Peter AU - Jahnich, Michael AU - Funke, Holger ID - 8446 T2 - Proceedings of 5th International Workshop on Automation of Software Test (AST 2010), ICSE Workshop TI - Pattern-based Generation of Test Plans for Open Distributed Processing Systems ER - TY - CONF AU - Brüseke, Frank AU - Sancar, Yavuz AU - Engels, Gregor ID - 8447 T2 - Proceedings of Software-Qualitätsmodellierung und -bewertung (SQMB '10), Paderborn, Germany TI - Architecture-Driven Derivation of Performance Metrics ER - TY - CONF AU - Güldali, Baris AU - Mlynarski, Michael AU - Sancar, Yavuz ID - 8448 T2 - Proceedings of 3th International Conference on Software Testing, Verification, and Validation Workshops TI - Effort Comparison of Model-based Testing Scenarios ER - TY - CONF AU - Schnelte, Matthias AU - Güldali, Baris ID - 8449 T2 - INFORMATIK 2010, Beiträge der 40. Jahrestagung der Gesellschaft für Informatik e.V. (GI) TI - Test Case Generation for Visual Contracts Using AI Planning ER - TY - JOUR AB - The hydrothermal method enables the production of high-quality piezoelectric materials. In this study, we propose to irradiate the reaction solutions with ultrasonic power during the hydrothermal method to obtain a shorter reaction time and a smooth film surface. A high-pressure reaction container for the ultrasonic transducer was newly developed, and the ultrasonically-assisted hydrothermal method was examined by using this container. The effect of ultrasonic assist on the synthesis of lead-zirconate-titanate (PZT) thin films and (K,Na)NbO$_{3}$ powders was verified. Thicker PZT film, thickness around 10 ${\mu}$m, could be obtained in one process, and (K,Na)NbO$_{3}$ powder was synthesized in half the previous reaction time. AU - Ageba, Ryo AU - Kadota, Yoichi AU - Maeda, Takafumi AU - Takiguchi, Norihito AU - Morita, Takeshi AU - Ishikawa, Mutsuo AU - Bornmann, Peter AU - Hemsel, Tobias ID - 9743 IS - 4 JF - Journal of Korean Physical Society KW - Hydrothermal method KW - High-power ultrasonic KW - PZT thin film KW - Lead-free piezoelectric materials SN - 1948-5719 TI - Ultrasonically-assisted Hydrothermal Method for Ferroelectric Material Synthesis VL - 57 ER - TY - JOUR AB - Direct ultrasound irradiation is advantageous to increase the efficiency of the hydrothermal method which can be used for the production of piezoelectric thin films and lead free piezoelectric ceramics. To apply ultrasound directly to the process transducer prototypes were developed regarding the boundary conditions of the hydrothermal method. LiNbO$_{3}$ and PIC 181 were proven as feasible materials for high temperature resistant transducers ($\geq 200^\circ C$). Resistance of the transducers horn against the corrosive mineralizer was achieved by using Hastelloy C-22. The efficiency of the ultrasound assisted hydrothermal method depends on the generated sound field. Impedance and sound field measurements have shown that the sound field depends on the filling level and the position and design of the transducer. AU - Bornmann, Peter AU - Hemsel, Tobias AU - Littmann, Walter AU - Ageba, Ryo AU - Kadota, Yoishi AU - Morita, Takeshi ID - 9744 IS - 4 JF - Journal of Korean Physical Society KW - High-temperature transducer KW - Hydrothermal method KW - Lithium-niobate transducer SN - 1948-5719 TI - Ultrasonic Transducer for the Hydrothermal Method VL - 57 ER - TY - JOUR AB - In the modeling of piezoelectric Langevin transducers using usual transfer matrix methods, some simplifications have been adopted. This leads to reduction of the model quality. A mixed transfer matrix method is employed in the modeling of Langevin transducers, where the pre-stressed bolt is modeled as a separate four-pole element, which is connected to other elements in parallel. Based on the mixed transfer matrix method, the four (six)-pole element description of the piezoelectric Langevin transducer is built up and the total transfer matrix relation is derived. The resonance frequencies of the transducer are calculated and then measured using the impedance analyzer (HP4192). Experimental result shows that the mixed transfer matrix method has better modeling quality than the usual transfer matrix method for the vibration analysis of piezoelectric Langevin transducers. AU - Fu, Bo AU - Li, Chao AU - Zhang, Jianming AU - Huang, Zhenwei AU - Hemsel, Tobias ID - 9745 IS - 4 JF - Journal of Korean Physical Society KW - Piezoelectric langevin transducer KW - Transfer matrix method KW - Four (six)-pole element description KW - Pre-stressed bolt SN - 1948-5719 TI - Modeling of Piezoelectric Langevin Transducers by Using Mixed Transfer Matrix Methods VL - 57 ER - TY - JOUR AB - Bei der Konstruktion von Maschinen ist es oftmals erforderlich, Schwingungen minimal zu halten. Um z.B. die Lebensdauer zu erhöhen, Material einzusparen oder den Geräuschpegel gering zu halten muss oft ein großer Aufwand zur Dämpfung von auftretenden Schwingungen betrieben werden. In vielen technischen Anwendungen werden Einzelteile miteinander verschraubt. Diese Fügestellen können gezielt und mit wenig Aufwand zur Schwingungsdämpfung herangezogen werden. Die Berechnung des dynamischen Verhaltens verschraubter Strukturen stellt immer noch eine Herausforderung dar. Es wurde eine Methode entwickelt, um den eingeschwungenen Zustand elastischer, miteinander verschraubter Körper mit rauen Fügestellen bei periodischer Anregung zu berechnen. Als Basis dienen Finite Elemente Modelle der einzelnen Teile, deren Freiheitsgrade durch modale Kondensation reduziert werden. Unter Anwendung des Verfahrens von Ritz und Galerkin wird eine Näherungslösung für den eingeschwungenen Zustand des nichtlinearen, gekoppelten Systems ermittelt. Abhängig von den Schraubenvorspannkräften sowie den bestimmenden Parametern der Kontaktflächen, Rautiefe und Reibungskoeffizient, kann die Systemantwort berechnet und optimiert werden. Um die Berechnungsmethode zu verifizieren wurden Experimente durchgeführt. Der Vergleich zwischen Messung und Rechnung zeigt eine gute Übereinstimmung. ({\copyright} 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) AU - Hölzl, Johannes Sebastian AU - Sextro, Walter ID - 9747 IS - 1 JF - PAMM SN - 1617-7061 TI - Reibungsdämpfung in ausgedehnten, verschraubten Fügestellen VL - 10 ER - TY - JOUR AB - For many technical applications it is necessary to avoid or to reduce vibrations. Factors benefiting from vibration reduction are for example the durability of the application, which is increased, as well as cost expenses and the level of noise, which are both decreased. Rough, bolted interfaces are common in most machines and can be used as damping devices with some effort. Perhaps in future such contact surfaces could be used as damping devices at the interfaces of an automotive engine or exhaust system. Nevertheless it is difficult to predict the effect of a change in contact interface parameters on the dynamic behavior of the entire mechanical system. Therefore a method for calculating the steady state behavior of elastic multi-body systems was developed. The basis of this method is a finite element model of each contacting unit. On each model a modal reduction is applied in order to reduce the degrees of freedom. The method of Ritz and Galerkin is used to calculate the frequency response functions of the reduced system including contact. This method allows the calculation of the steady-state behavior of elastic multi-body systems with rough, bolted contact interfaces, by taking the pre-stress of the bolts, the roughness and the friction coefficient of the contacting surfaces as parameters. In order to verify calculated results, a test stand was built. The comparison of calculated and experimental results showed a satisfying correlation. AU - Hölzl, Johannes Sebastian AU - Sextro, Walter ID - 9748 JF - SAE International Journal of Passenger Cars- Mechanical Systems KW - Automotive TI - Simulation of the Dynamical Behavior of Elastic Multi-Body Systems with Bolted, Rough Contact Interfaces ER - TY - JOUR AB - Piezoelectric materials find wide application in technical systems. Most often, a combination of piezoelectric and other materials is advantageous. The position and the amount of the piezoelectric material within the overall system depends on various aspects like maximum mechanical output to the load, maximum electromechanical efficiency of the system, maximum utilization of the piezoelectric material, minimum self-heating of the piezoelectric material, and controllability of the system, which might be key aspects for the optimisation of the system design. For a composite longitudinal vibrator (bolted Langevin transducer), which is a base for many technical applications, this contribution shows in detail, how above mentioned aspects depend on the position and volume of the piezoelectric material related to the mode shape. AU - Hemsel, Tobias AU - Lierk, Ernst Günther AU - Littmann, Walter AU - Morita, Takeshi ID - 9749 IS - 4 JF - Journal of Korean Physical Society KW - Bolted Langevin transducer KW - Optimum placement of piezoelectric ceramics SN - 1948-5719 TI - Various Aspects of the Placement of a Piezoelectric Material in Composite Actuators, Motors, and Transducers VL - 57 ER - TY - JOUR AU - Hess, D. AU - Hüfner, Thorsten AU - Hesse, Tobias AU - Sondermann-Wölke, Christoph AU - Sattel, Thomas ID - 9750 JF - Internationales Mechatronik-Kolloquium "Mechatronik 2010" TI - Intelligente mechatronische Systeme zur automatisierten Fahrzeugführung in Fahrerassistenzsystemen ER - TY - JOUR AB - Piezoelectric inertia motors have a simple construction and are controlled by a single driving signal. This allows for miniaturization and low cost production. One of the main questions to be answered during the design process of a piezoelectric inertia motor is which electrical excitation signal yields optimum motor characteristics. Three signals and their variants are widely used in literature: sawtooth, parabolic and cycloidic signals. It can be shown that neither of these can drive the motor at its maximum possible velocity in non-resonant operation. Within this paper we propose to use a rigid body model of a simple inertia motor to predict the motor characteristics depending on the movement pattern of the driving element. Advantages and disadvantages of three different drive signals that maximize the motor velocity are discussed. AU - Hunstig, Matthias AU - Hemsel, Tobias ID - 9751 IS - 4 JF - Journal of Korean Physical Society SN - 1948-5719 TI - Drive Signals for Maximizing the Velocity of Piezoelectric Inertia Motors VL - 57 ER - TY - JOUR AB - Piezoelectric inertia motors make use of the inertia of a slider to drive the slider by friction contact in a series of small steps which are generally composed of a stick phase and a slip phase. If the best electrical drive signal for the piezoelectric actuator in an inertia motor is to be determined, its dynamical behaviour must be known. A classic dynamic lumped parameter model for piezoelectric actuators is valid only in resonance and, therefore, is not suitable for modelling the actuator in an inertia motor. A reduced dynamic model is used instead. Its parameters are identified using a step response measurement. This model is used to predict the movement of the actuator in response to a velocity-optimized signal introduced in a separate contribution. Results show that the model cannot represent the dynamical characteristics of the actuator completely. For determining voltage signals that let piezoelectric actuators follow a calculated movement pattern exactly, the model can, therefore, only be used with limitations. AU - Hunstig, Matthias AU - Hemsel, Tobias ID - 9752 IS - 4 JF - Journal of Korean Physical Society SN - 1948-5719 TI - Parameter Identification and Model Validation for the Piezoelectric Actuator in an Inertia Motor VL - 57 ER - TY - CONF AB - Piezoelektrische Trägheitsmotoren nutzen die Trägheit einer bewegten Masse, um diese in kleinen Schritten durch abwechselnde Haft- und Gleitphasen voranzutreiben. Eine Kernfrage bei der Entwicklung eines piezoelektrischen Trägheitsmotors ist, welches elektrische Ansteuersignal für das gewünschte Motorverhalten optimal ist. Das elektrische Signal führt zu einer Bewegung des piezoelektrischen Aktors und damit der Antriebsstange, die den reibschlüssigen Vortrieb bewirkt. Entsprechend wird diese Fragestellung in zwei Teilen untersucht: Anhand eines Starrkörpermodells werden zunächst Bewegungsverläufe für die Antriebsstange ermittelt, mit denen die maximale Geschwindigkeit erreicht wird. Dabei werden drei Antriebsmodi identifiziert. Mit allen kann eine höhere Geschwindigkeit als mit der heute häufig verwendeten Sägezahnanregung erreicht werden. Anschließend wird ein einfaches dynamisches Modell eines piezoelektrischen Aktors genutzt, um die notwendigen elektrischen Ansteuersignale für die verschiedenen Antriebsmodi zu bestimmen. Es zeigt sich, dass das gewählte einfache Modell hierzu nur bedingt geeignet ist. AU - Hunstig, Matthias AU - Hemsel, Tobias AU - Sextro, Walter ED - Gausemeier, Jürgen ED - Rammig, Franz ED - Schäfer, Wilhelm ED - Trächtler, Ansgar ID - 9753 KW - Piezoelektrischer Trägheitsmotoren SN - 0924-4247 T2 - 7. Paderborner Workshop Entwurf mechatronischer Systeme TI - Anregungskonzepte und Modellierung piezoelektrischer Trägheitsmotoren VL - 272 ER - TY - CONF AB - A model based design approach for improved piezoelectric inertia motors is presented. Three velocityoptimized movement patterns for the driving body have been derived. The influence of the motor parameters and the process of designing an application specific motor with maximum velocity are shown. A simple dynamic model of the piezoelectric actuator is used to calculate the voltage signal for achieving the desired movement pattern. Observed distortions of the optimum pattern, their influence on the motion of the driven body and different methods to reduce them are discussed. AU - Hunstig, Matthias AU - Hemsel, Tobias AU - Sextro, Walter ID - 9754 SN - 0924-4247 T2 - ACTUATOR 2010 Conference Proceedings TI - Improving the Performance of Piezoelectric Inertia Motors ER - TY - CONF AU - Kraft , Verena AU - Bauch, C. AU - Nückel, M. AU - Hemsel, Tobias ID - 9755 T2 - 19. Gemeinschaftstagung LICHT 2010 TI - Konzeption und Aufbau eines Langzeitforschungsstandes zur lichttechnischen Charakterisierung von organischen Leuchtdioden (OLEDs) ER - TY - JOUR AB - Dieser Beitrag fasst die bekannten analytischen Berechnungsmethoden für piezoelektrische Ultraschallverbundschwinger zusammen und gibt anhand typischer Beispiele Anleitungen zur Lösung theoretischer und technischer Fragen bei deren Entwicklung. Zunächst werden die passiven, in der Regel metallischen Komponenten von Verbundschwingern als Stab- oder Plattensysteme mit homogen verteilten Feder-, Masse und Dämpfungseigenschaften beschrieben. Hier breitet sich die Schwingungsenergie in Form stehender und fortschreitender Wellen zum akustischen Verbraucher hin aus. Es folgt eine gleichwertige und schaltungstreue Darstellung durch elektrische oder mechanische Vierpole, die für den Entwicklungsingenieur leichter zu handhaben sind und in Netzwerken direkt mit Masons Ersatzschaltung des piezoelektrischen Wandlers gekoppelt werden können. Danach werden die wichtigsten, messtechnisch zugänglichen Parameter anhand eines in Resonanznähe zulässigen Ersatzmodells mit konzentrierten elektrischen bzw. mechanischen Komponenten definiert. Als Schwerpunkt wird anschließend deren analytische Berechnung und messtechnische Verifizierung an typischen Beispielen demonstriert. Es folgen wichtige technische Informationen über Frequenzkorrekturen, Schallgeschwindigkeitsdispersion, Leistungs- und Belastbarkeitsgrenzen der Komponenten und andere wertvolle praktische Hinweise. AU - Lierke, Ernst-Günter AU - Littmann, Walter AU - Hemsel, Tobias ID - 9756 JF - Veröffentlichung der Universität Paderborn SN - 1948-5719 TI - Zur Theorie der piezoelektrischen Ultraschallverbundschwinger mit praktischen Schlussfolgerungen für den Entwicklungsingenieur ER - TY - JOUR AU - Lucinskis, Raimundas AU - Mazeika, Dalius AU - Hemsel, Tobias AU - Bansevicius, Ramutis ID - 9757 JF - MECHANIKA SN - 1948-5719 TI - The experimental research of piezoelectric actuator with two vectors of polarization direction ER - TY - JOUR AB - As a lead-free piezoelectric ceramics, (K,Na)NbO$_{3}$ is a promising material because of its good piezoelectric properties. In this study, (K$_{1-x}$Na$_{x}$)NbO$_{3}$ ceramics were synthesized from a KNbO$_{3}$ and NaNbO$_{3}$ mixture powder prepared by the hydrothermal reaction. The hydrothermal reaction enables the production of high quality powder for the ceramics fabrication process. To obtain (K$_{1-x}$Na$_{x}$)NbO$_{3}$ ceramics, these two powders KNbO$_{3}$ and NaNbO$_{3}$ were mixed and then sintered together. X-Ray diffraction analysis revealed that the solid solution ceramics (K$_{1-x}$Na$_{x}$)NbO$_{3}$ was produced by the sintering process. The K/Na ratio in (K$_{1-x}$Na$_{x}$)NbO$_{3}$ ceramics was optimized for the best piezoelectric properties. The optimized forms was (K$_{0.48}$Na$_{0.52}$)NbO$_{3}$, which showed the following piezoelectric properties; k$_{33}$=0.56, d$_{33}$=114pC/N. In addition, the ferroelectric properties, P$_{r}$=7.72mC/cm$^{2}$, E$_{c}$=857V/mm, and the Curie temperature T$_{c}$=420$_{o}$C were also measured. AU - Maeda, Takafumi AU - Takiguchi, Norihito AU - Morita, Takeshi AU - Ishikawa, Mutsuo AU - Hemsel, Tobias ID - 9758 IS - 4 JF - Journal of Korean Physical Society KW - Lead-free piezoelectric material KW - KNN KW - Hydrothermal method SN - 1948-5719 TI - Hydrothermal (K1-xNax)NbO3 Lead-free Piezoelectric Ceramics VL - 57 ER - TY - JOUR AB - Among various lead-free piezoelectric materials, (K,Na)NbO$_{3}$ is a very promising candidate. In this study, (K,Na)NbO$_{3}$ ceramics were sintered from mixed (K,Na)NbO$_{3}$ and NaNbO$_{3}$ powders prepared by hydrothermal reaction. These two powders were mixed with distilled water in a KNbO$_{3}$/NaNbO$_{3}$ molar ratio of 1. After sintering the mixed powder, the solid solution of (Na,K)NbO$_{3}$ ceramics was obtained. The electrical properties such as the electromechanical coupling factors k$_{p}$ and k$_{33}$, the mechanical quality factor, Q$_{m}$, and the piezoelectric constant d$_{33}$ of the sintered (K,Na)NbO$_{3}$ ceramics were 0.32, 0.48, 71 (radial mode), 118 ((33)mode), and 107 pC/N, respectively. AU - Maeda, Takafumi AU - Takiguchi, Norihito AU - Morita, Takeshi AU - Ishikawa, Mutsuo AU - Hemsel, Tobias ID - 9759 IS - 2 JF - Materials Letters KW - Lead-free piezoelectric material KW - (K KW - Na)NbO$_{3}$ ceramics KW - Sintering solid solution KW - Piezoelectric properties SN - 1948-5719 TI - (K,Na)NbO3 lead-free piezoelectric ceramics synthesized from hydrothermal powders VL - 64 ER - TY - CONF AB - Self-optimizing systems are able to adapt their behavior autonomously according to their current self-determined objectives. Unforeseen influences could lead to dependability-critical behavior of the system. Methods are required which secure self-optimizing systems during operation. These methods to increase the dependability of the system should already be taken into consideration in the design process. This paper presents a guideline for the dependability-oriented design of self-optimizing systems, which integrates established classical methods like failure mode and effects analysis as well as methods based on self-optimization. On the one hand self-optimization is used to increase the dependability of the system by integrating objectives like safety, availability, and reliability to the objectives of the system. On the other hand methods are required to ensure the self-optimization itself. As basis for this guideline serves the principle solution of the system. The six phases of the guideline extend the design process and lead to an enhanced principle solution. Additionally, the guideline illustrates phases to implement and validate the self-optimizing system. The proposed guideline is applied to an innovative rail-bound vehicle, called RailCab, which is equipped with self-optimizing function modules. AU - Sondermann-Wölke, Christoph AU - Hemsel, Tobias AU - Sextro, Walter AU - Gausemeier, Jürgen AU - Pook, Sebastian ID - 9760 KW - RailCab KW - dependability-critical behavior KW - dependability-oriented design KW - failure mode KW - rail-bound vehicle KW - secure self-optimizing systems KW - self-optimizing function modules KW - optimisation KW - railways KW - self-adjusting systems T2 - Industrial Informatics (INDIN), 2010 8th IEEE International Conference on TI - Guideline for the dependability-oriented design of self-optimizing systems ER - TY - JOUR AB - New mechatronic systems, called self-optimizing systems, are able to adapt their behavior according to environmental, user and system specific influences. Self-optimizing systems are complex and due to their non-deterministic behavior comprise hidden risks, which cannot be foreseen in the design phase of the system. Therefore, modifications of the ISO 17359 condition monitoring policy for being able to cope with this new kind of systems are presented. Besides avoiding critical situations evoked by self-optimization, the proposed concept uses self-optimization to increase the dependability of the system. This concept is applied to the active guidance module of an innovative rail-bound vehicle. First test drives provide information for the enhancement of the implementation of realtime switching to appropriate control strategies. The different control strategies are investigated in detail. It is illustrated that influences on the system like different track sections or the desired velocity of the RailCab effect the system and can lead to a higher amount of flange contacts, which indicate higher wear and thus a reduction of the availability of the system. Therefore, these influences should be minded within the condition monitoring policy. Consequently, this article presents the condition monitoring policy for self-optimizing function modules and its application to the active railway guidance module. AU - Sondermann-Wölke, Christoph AU - Sextro, Walter ID - 9761 IS - 1 - 3 JF - International Journal On Advances in Intelligent Systems KW - dependability KW - condition monitoring KW - selfoptimization KW - active railway guidance module TI - Integration of Condition Monitoring in Self-optimizing Function Modules Applied to the Active Railway Guidance Module VL - 3 ER - TY - CONF AB - Die erweiterten Möglichkeiten der Informationsverarbeitung mechatronischer Systeme erlauben es, mechatronische Systeme selbstoptimierend zu gestalten. Dabei bezieht sich die Selbstoptimierung auf die Fähigkeit des Systems, sich an die aktuelle Umfeldsituation anzupassen; wobei das System im Allgemeinen mehrere relevante Ziele verfolgt. Wurde eine Umfeldveränderung bemerkt, so müssen diese Ziele an die neue Situation angepasst und das resultierende Verhalten ausgewählt werden. In diesem Beitrag wird das selbstoptimierende Spurführungsmodul näher untersucht. Das Spurführungsmodul ist Bestandteil eines innovativen schienengebundenen Verkehrssystems, genannt RailCab, und dient zur Lenkung des einzelnen Fahrzeugs. Ziele des Spurführungsmoduls bestehen darin, die Verlässlichkeit des Spurführungsmoduls zu erhöhen sowie möglichst wenig Energie zu verbrauchen. Um kritische Systemzustände zu erkennen bzw. frühzeitig zu verhindern wird eine Vorgehensweise zur Einrichtung einer Zustandsüberwachung für selbstoptimierende Systeme beschrieben. Diese wird auf dem realen Versuchsträger im Maßstab 1:2,5 implementiert. Die Auswertung von Versuchsfahrten zeigt, dass gerade beim Auftreten eines Fehlers das Umschalten vom Ziel ''Energieverbrauch minimieren`` auf das Ziel ''Verlässlichkeit maximieren`` sinnvoll ist. AU - Sondermann-Wölke, Christoph AU - Sextro, Walter AU - Geisler, Jens AU - Trächtler, Ansgar ED - Gausemeier, Jürgen ED - Rammig, Frans Josef ED - Trächtler, Ansgar ID - 9762 KW - Selbstoptimierung KW - Spurführungsmodul T2 - Entwurf mechatronischer Systeme TI - Experimentelle Untersuchung der Selbstoptimierung innerhalb des RailCab-Spurführungsmoduls VL - 272 ER - TY - CONF AB - Recent advances in information processing enable new kinds of technical systems, called self-optimizing systems. These systems are able to adapt their objectives and their behavior according to the current situation and influences autonomously. This behavior adaptation is non-deterministic and hence self-optimization is a risk to the system, e.g. if the result of the self-optimization process does not match the suddenly changed situation. In contrary, self-optimization could be used to increase the dependability by pursuing objectives like reliability and availability. In our preceding publications we introduced the so called multi-level dependability concept to cope with this new kind of systems (cf. [6]). This concept comprises the monitoring of the system behavior, the classification of the current situation, and the selection of the appropriate measure, if reliability limits are exceeded. In this paper we present for the first time experimental results. The dependability concept is implemented in the self-optimizing active guidance system of a railway vehicle. The test drives illustrate clearly that the proposed concept is able to cope with, e.g., sensor failures, and is able to increase the reliability and availability of the active guidance module. AU - Sondermann-Wölke, Christoph AU - Geisler, Jens AU - Sextro, Walter ID - 9763 KW - availability KW - dependability concept KW - multilevel dependability concept KW - railway vehicle KW - reliability KW - self optimizing active guidance system KW - self optimizing railway guidance system KW - situation classification KW - system behavior monitoring KW - optimal control KW - railways KW - reliability theory KW - self-adjusting systems SN - 0149-144X T2 - Reliability and Maintainability Symposium (RAMS), 2010 Proceedings - Annual TI - Increasing the reliability of a self-optimizing railway guidance system ER - TY - JOUR AU - Tomberger, Christoph AU - Dietmaier, Peter AU - Martin, Rosenberger AU - Sextro, Walter AU - Six, Klaus ID - 9764 JF - ZEVrail SN - 0043-1648 TI - Einfluss von Oberflächenrauheit, fluiden Zwischenschichten und Kontakttemperaturen auf den Kraftschluss zwischen Rad und Schiene VL - 134 ER - TY - JOUR AB - We study a single quantum dot molecule doped with one electron in the presence of electron-phonon coupling. Both diagonal and off-diagonal interactions representing real and virtual processes with acoustic phonons via deformation potential and piezoelectric coupling are taken into account. We employ a non-perturbative quantum kinetic theory and show that the phonon-mediated relaxation is dominated by an electron tunneling on a picosecond time scale.A dependence of the relaxation on the temperature and the strength of the tunneling coupling is analyzed. AU - Grodecka-Grad, Anna AU - Förstner, Jens ID - 4129 JF - Journal of Physics: Conference Series KW - tet_topic_qd SN - 1742-6596 TI - Phonon-mediated relaxation in doped quantum dot molecules VL - 245 ER - TY - JOUR AB - Non-polar relaxed cubic GaN was grown by molecular beam epitaxy (MBE) on nano-patterned 3C-SiC/Si (0 0 1)substrates with negligible hexagonal content and less defect density than in planar cubic GaN layers.Nano-patterning of 3C-SiC/Si(001) is achieved by self-ordered colloidal masks for the first time. The method presented here offers the possibility to create nano-patterned cubic GaN without the need for a GaN etching process andt hus isa potential alternative to the conventional top–down fabrication techniques. AU - Kemper, R.M. AU - Weinl, M. AU - Mietze, C. AU - Häberlen, M. AU - Schupp, T. AU - Tschumak, E. AU - Lindner, Jörg AU - Lischka, K. AU - As, Donald ID - 4144 IS - 1 JF - Journal of Crystal Growth SN - 0022-0248 TI - Growth of cubic GaN on nano-patterned 3C-SiC/Si (001) substrates VL - 323 ER - TY - JOUR AB - Nanosphere lithography (NSL) masks consisting of mono- or double-layers of polystyrene (PS) nano-beads are fabricated on silicon exploiting the self-organization of PS particles during the controlled drying of a colloidal suspension on a surface. The shape changes and shrinkage of PS sphere masks upon treatment in an air plasma are studied as a function of initial sphere size, plasma power and treatment time. The influence of several experimental parameters, including the plasma induced temperature rise, are analysed using scanning and transmission electron microscopy. It is demonstrated that a variety of new intriguing nanopatterns can be generated on silicon surfaces by the combination of NSL and plasma techniques, largely broadening the variety of patterns available so far by NSL. AU - Gogel, D. AU - Weinl, M. AU - Lindner, Jörg AU - Stritzker, B. ID - 4153 IS - 3 JF - JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS TI - Plasma modification of nanosphere lithography masks made of polystyrene beads VL - 12 ER -