TY - GEN
ED - Ehrig, Hartmut
ED - Engels, Gregor
ED - Kreowksi, H.-J.
ED - Taentzer, Gabriele
ID - 7790
IS - 2
TI - Special Issue: Selected Papers of GRATRA 2000
VL - 44
ER -
TY - JOUR
AB - Piezoelectric ultrasonic motors have been investigated for several years and have already found their first practical applications. Their key feature is that they are able to produce a high thrust force related to their volume. Beside rotary drives like the travelling wave motor, linear drives have also been developed, but only a few are presently commercially available. In the present paper, we first describe the state of the art of linear piezoelectric motors. The motors are characterized with respect to their no-load velocity, maximum thrust force, efficiency and other technical properties. In the second part, we present a new motor, which is judged to be capable of surpassing the characteristics of other piezoelectric motors because of its unique design which allows the piezoelectric drive elements to be pre-stressed in the direction of their polarization. The piezoelectric elements convert energy using the longitudinal d33 effect which allows an improved reliability, large vibration amplitudes and excellent piezoelectric coupling. Energy loss by vibration damping is minimized, and the efficiency can be improved significantly. Experimental results show that the motor characteristics can be optimized for a particular task by choosing the appropriate operating parameters such as exciting voltage, exciting frequency and normal force.
AU - Hemsel, Tobias
AU - Wallaschek, Jörg
ID - 8914
JF - Ultrasonics
KW - Linear motor
SN - 0041-624X
TI - Survey of the present state of the art of piezoelectric linear motors
VL - 38
ER -
TY - CONF
AB - the vibration amplitudes of bladed disk assemblies can be reduced significantly by means of friction damping devices such as shrouds, damping wires and interblade Friction dampers. in practice, interblade Friction dampers are applied in rotating arrangements with various geometries showing curved or flat surfaces like so-called wedge-shaped dampers. this paper is focusing on a computation method to predict the dynamical behaviour of turbine blades with Friction dampers including both, curved and wedge-shaped dampers with hertzian and non-herutian contact conditions, respectively. the presented computation method uses a 3d contact model to calculate the contact forces, including normal and tangential stiffnesses, roughness and microslip effects. the relative displacements in the contact area can be expressed by means of 6 dof of the blade platforms and 6 rigid body dof of the damper including translational and rotational displacements. the relative displacement of the Friction damper with respect to the adjacent blades can be derived from the contact kinematics of the blade-damper-blade system and the equations of motion of the Friction damper. thus, the model can be applied to investigate spatial motions of the bladed disk assembly including bending and torsional vibrations. a comparison of different Friction damper designs with respect to an optimal damper geometry and damper mass is presented. the advantages and disadvantages of each design will be discussed. experimental results are shown to validate the developed computation method.
AU - Panning, Lars
AU - Sextro, Walter
AU - Popp, Karl
ID - 8919
T2 - International Gas Turbine \& Aeroengine Congress \& Exhibition, ASME
TI - Optimization of Interblade Friction Damper
ER -
TY - CHAP
AU - Kremer, H.-Hugo
ED - Euler, D.
ED - Jongebloed, H.-C.
ED - Sloane, P.F.E.
ID - 8457
T2 - Sozialökonomische Theorie - sozialökonomisches Handeln. Konturen und Perspektiven der Wirtschafts- und Sozialpädagogik
TI - Didaktische Theorie implementieren - Innovationen gestalten
ER -
TY - CONF
AB - Graphs are a commonly used formalism for modeling many different kinds of static and dynamic data. In many applications, data modeling can be improved by using hierarchically structured graphs. But, while there already exist hierarchical graph data models, no general-purpose hierarchical graph data model exists yet, which unifies common features of these domain-specific models. In this paper, we present graph packages, a general formalism for defining hierarchical graphs, supporting the most important features found in known applications. Because of the dynamic nature of graphs, hierarchical graph transformation is also an important issue to be dealt with when using hierarchical graphs. Motivated by the successful application of graph grammars to the specification of graph transformations, we also introduce a framework that allows to specify hierarchical graph transformations by combining existing graph grammar approaches and our graph package concept. These concepts are a step towards the definition of a general-purpose hierarchical graph data model.
AU - Busatto, Giorgio
AU - Engels, Gregor
AU - Mehner, Katharina
AU - Wagner, Annika
ID - 8332
T2 - Selected Papers of the 6th International Workshop on Theory and Application of Graph Transformations (TAGT '98), Paderborn (Germany)
TI - A Framework for Adding Packages to Graph Transformation Approaches
VL - 1764
ER -
TY - CONF
AU - Depke, Ralph
AU - Heckel, Reiko
AU - Küster, Jochen
ID - 8337
T2 - Proceedings of the Workshop des Arbeitskreises GROOM der GI Fachgruppe 2.1.9 Objektorientierte Software-Entwicklung on Visuelle Verhaltensmodellierung verteilter und nebenläufiger Software-Systeme, Münster (Germany)
TI - Rollenbasierte Modellierung autonomer Agenten
ER -
TY - CONF
AU - Heckel, Reiko
AU - Sauer, Stefan
ID - 8344
IS - 0006
T2 - Proceedings of the Workshop on Dynamic Behaviour in UML Models: Semantic Questions, Munich (Germany)
TI - Strengthening the Semantics of UML Collaboration Diagrams
ER -
TY - JOUR
AU - Dellnitz, Michael
AU - Froyland, Gary
AU - Sertl, Stefan
ID - 16554
JF - Nonlinearity
SN - 0951-7715
TI - On the isolated spectrum of the Perron-Frobenius operator
ER -
TY - JOUR
AU - Meyer auf der Heide, Friedhelm
AU - Wanka, Rolf
ID - 16345
JF - ForschungsForum Paderborn
TI - Von der Hollerith-Maschine zum Parallelrechner - Die alltägliche Aufgabe des Sortierens als Fortschrittsmotor für die Informatik
ER -
TY - CHAP
AU - Peckhaus, Volker
ED - Kusch, Martin
ID - 17526
T2 - The Sociology of Philosophical Knowledge
TI - The Contextualism of Philosophy
VL - 48
ER -
TY - GEN
AU - Peckhaus, Volker
ID - 18341
T2 - Zentralblatt für Mathematik und ihre Grenzgebiete [Zbl. 934.01004]
TI - Müller, Ralf, Die dynamische Logik des Erkennens von Charles S. Peirce, Königshausen & Neumann: Würzburg 1999
ER -
TY - GEN
AU - Peckhaus, Volker
ID - 18358
T2 - Zentralblatt für Mathematik und ihre Grenzgebiete [Zbl. 942.03002]
TI - Zach, Richard, “Completeness before Post: Bernays, Hilbert, and the Development of Propositional Logic”, Bulletin of Symbolic Logic 5 (1999), 331–366
ER -
TY - GEN
AU - Peckhaus, Volker
ID - 18360
T2 - Zentralblatt für Mathematik und ihre Grenzgebiete [Zbl. 946.01004]
TI - Glashoff, Klaus, „Das Rad der Gründe — Der Hetucakradamara von Dignaga“, Mitt. Math. Ges. Hamb. 18 (1999), 75–104
ER -
TY - CONF
AB - We present a general framework for the development of on-line algorithms for data management in networks with limited memory capacities. These algorithms dynamically create and delete copies of shared data objects that can be read and written by the nodes in the network. Our algorithms aim to minimize the congestion, i.e., the maximum communication load over all network resources, so that that none of these resources become a communication bottleneck. We give several examples of networks for which our framework yields efficient algorithms, including meshes, fat-trees, hypercubic networks, and complete networks. For example, our framework yields an $O(d cdot log n)$-competitive caching algorithm for $d$-dimensional meshes of size $n$ with respect to the congestion on the communication links, and an $O(1)$-competitive algorithms for complete networks with respect to the congestion at the memory modules due to remote accesses. Previous work on data management in networks either neglects memory capacity constraints or minimizes only the total communication load, i.e., the sum of the communication load over all resources, which may produce congestion as some of the links become bottlenecks.
AU - Meyer auf der Heide, Friedhelm
AU - Vöcking, Berthold
AU - Westermann, Matthias
ID - 16496
SN - 0898714532
T2 - SODA '00: Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms
TI - Caching in networks
ER -
TY - BOOK
AB - 2., kartonierte Auflage: Berlin 2002
ED - Allkemper, Alo
ED - Eke, Norbert Otto
ID - 19084
TI - Deutsche Dramatiker des 20. Jahrhunderts
ER -
TY - CONF
AU - Eke, Norbert Otto
ED - Eke, Norbert Otto
ED - Werner, Renate
ID - 19402
T2 - Vormärz – Nachmärz. Bruch oder Kontinuität? Vorträge des Symposions des Forum Vormärz Forschung e.V. vom 19.-21. November 1998 an der Universität Paderborn
TI - Vormärz/Nachmärz. – Bruch oder Kontinuität? Nachfragen an die Begriffsgeschichte
ER -
TY - CHAP
AU - Eke, Norbert Otto
ED - Allkemper, Alo
ED - Eke, Norbert Otto
ID - 19399
T2 - Deutsche Dramatiker des 20. Jahrhunderts
TI - Thomas Brasch
ER -
TY - GEN
AU - Eke, Norbert Otto
ID - 19546
IS - H. 1
T2 - Germanistik
TI - Horst Domdey: Produktivkraft Tod. Das Drama Heiner Müllers. Köln u.a.: Böhlau, 1998
VL - 41
ER -
TY - CONF
AU - Bednara, M.
AU - Beyer, O.
AU - Teich, J.
AU - Wanka, R.
ID - 19849
SN - 0769507166
T2 - Proc. Int. Conf. on Application Specific Systems, Architectures, and Processors (ASAP)
TI - Tradeoff analysis and architecture design of a hybrid hardware/software sorter
ER -
TY - CONF
AU - Brinkmann, André
AU - Salzwedel, Kay
AU - Scheideler, Christian
ID - 2149
T2 - SPAA
TI - Efficient, distributed data placement strategies for storage area networks (extended abstract)
ER -