TY - JOUR
AB - Numerical predictions of the forced vibration of a disk assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process. Assuming a tuned disk assembly, numerical static, free, and then forced vibration analyses of a shrouded turbine blade measured in the spin pit are performed systematically. For the excitation forces of an air jet evaluated from the fairly linear behavior of the experimental blade resonance peaks, the reliability of the proposed approach is validated through the very close agreement of the computed and measured resonant peaks. These resonant peaks demonstrate either a fairly linear behavior or a nonlinear one like the jump effect of blade resonance amplitudes, or elastic impacts between the shrouds. Also, the damping performance for different contact configurations between the shrouds is numerically analyzed. These numerical results indicate that the shrouds generate higher frictional damping for small angles (0{\^a}30deg) between the circumferential direction and the normal vector to the contact surface.
AU - Szwedowicz, J
AU - Visser, R
AU - Sextro, Walter
AU - Masserey, P. A
ID - 9567
IS - 1
JF - Journal of Turbomachinery
SN - 0889-504X
TI - On Nonlinear Forced Vibration of Shrouded Turbine Blades
VL - 130
ER -
TY - CONF
AU - Schütze, Oliver
AU - Talbi, El-ghazali
AU - Pulido, Gregorio Toscano
AU - Coello, Carlos Coello
AU - Santana-Quintero, Luis Vicente
ID - 16666
SN - 1424407087
T2 - 2007 IEEE Swarm Intelligence Symposium
TI - A Memetic PSO Algorithm for Scalar Optimization Problems
ER -
TY - CONF
AB - This paper formulates the dynamical equations of mechanics subject to holonomic constraints in terms of the states and controls using a constrained version of the Lagrange-d’Alembert principle. Based on a discrete version of this principle, a structure preserving time-stepping scheme is derived. It is shown that this respect for the mechanical structure (such as a reliable computation of the energy and momentum budget, without numerical dissipation) is retained when the system is reduced to its minimal dimension by the discrete null space method. Together with initial and final conditions on the configuration and conjugate momentum, the reduced time-stepping equations serve as nonlinear equality constraints for the minimisation of a given cost functional. The algorithm yields a sequence of discrete configurations together with a sequence of actuating forces, optimally guiding the system from the initial to the desired final state. The resulting discrete optimal control algorithm is shown to have excellent energy and momentum properties, which are illustrated by two specific examples, namely reorientation and repositioning of a rigid body subject to external forces and the reorientation of a rigid body with internal momentum wheels.
AU - Leyendecker, Sigrid
AU - Ober-Blöbaum, Sina
AU - Marsden, Jerrold E.
AU - Ortiz, Michael
ID - 16630
SN - 079184806X
T2 - Volume 5: 6th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, Parts A, B, and C
TI - Discrete Mechanics and Optimal Control for Constrained Multibody Dynamics
ER -
TY - CHAP
AU - Bähring, Katrin
AU - Thommes, Kirsten
ED - Schreyögg, Georg
ED - Sydow, Jörg
ID - 4985
SN - 978-3-8349-0575-8
T2 - Kooperation und Konkurrenz
TI - Kooperation und Konkurrenz in Personaldienstleistungsbeziehungen
ER -
TY - GEN
AU - Peckhaus, Volker
ID - 17796
T2 - Bulletin of Symbolic Logic
TI - Karl Sigmund/John Dawson/Kurt Mühlberger, Kurt Gödel. Das Album. The Album, Vieweg: Wiesbaden 2006
VL - 13
ER -
TY - CONF
AB - The paper introduces an online user study onapplications for social robots with 127 participants. The potential users proposed 570 application scenarios based on the appearance and functionality of four robots presented (AIBO,BARTHOC, BIRON, iCat). The items were grouped into 13 categories which are interpreted and discussed by means of four dimensions: public vs. private use, intensity of interaction,complexity of interaction model, and functional vs. human-like appearance. The interpretation lead to three classes of applications for social robots according to the degree of social interaction: (1) Specialized Applications where the robot has to perform clearly defined tasks which are delegated by a user, (2)Public Applications which are directed to the communication with many users, and (3) Individual Applications with the need of a highly elaborated social model to maintain a variety of situations with few people.
AU - Hegel, Frank
AU - Lohse, Manja
AU - Swadzba, Agnes
AU - Wachsmuth, Sven
AU - Rohlfing, Katharina
AU - Wrede, Britta
ID - 17284
T2 - 16th IEEE International Symposium on Robot and Human Interactive Communication (RO-MAN’07)
TI - Classes of Applications for Social Robots: A User Study
ER -
TY - JOUR
AU - Ziegler, Martin
ID - 17981
JF - Theory of Computing Systems
SN - 1432-4350
TI - Real Hypercomputation and Continuity
ER -
TY - BOOK
AB - Rezension: Neue Zürcher Zeitung v. 6. Juni 2007 (G. Szpiro); Ralf Bülow, “Hundert Jahre moderne Mathematik”, heise online v. 13.02.2008 (http://www.heise.de/newsticker/Hundert-Jahre-moderne-Mathematik–/meldung/103411); Mathematical Reviews 2007m:01024 (J.M. Plotkin); MAA Online 5. Juli 2007 (M. Berg); Philip J. Davis, “The Z of ZF and ZFC and ZF¬C”, SIAM News 41.1, January/February 2008; SIAM Review 50.1 (2008), 167–169; (J.W. Dawson); European Mathematical Society Newsletter June 2008, 54; The Mathematical Intelligencer 31 (2009), 79–81 (Henry E. Heatherly); Notices of the AMS 56 (2009), 823–827 (G.H. Moore); Zbl. Math. 1176.01001 (H.K. Sørensen).
AU - Ebbinghaus, Heinz-Dieter
AU - Peckhaus, Volker
ID - 17448
TI - Ernst Zermelo. An Approach to His Life and Work
ER -
TY - GEN
AU - Peckhaus, Volker
ID - 18643
T2 - Zentralblatt für Mathematik und ihre Grenzgebiete [Zbl. 1111.68301; Wiederabdruck von MR 2003d:68002]
TI - Vollmar, Roland, „Von Zielen und Grenzen der Informatik“, Abh. Braunschw. Wiss. Ges. 51 (2002), 9–24
ER -
TY - CONF
AB - We study graph properties which are testable for bounded degree graphs in time independent of the input size. Our goal is to distinguish between graphs having a predetermined graph property and graphs that are far from every graph having that property. It is believed that almost all, even very simple graph properties require a large complexity to be tested for arbitrary (bounded degree) graphs. Therefore in this paper we focus our attention on testing graph properties for special classes of graphs. We call a graph family non-expanding if every graph in this family is not a weak expander (its expansion is O(1/log2 n), where n is the graph size). A graph family is hereditary if it is closed under vertex removal. Similarly, a graph property is hereditary if it is closed under vertex removal. Next, we call a graph property Π to be testable for a graph family F if for every graph G ε F, in time independent of the size of G we can distinguish between the case when G satisfies property Π and when it is far from every graph satisfying property Π. In this paper we prove thatIn the bounded degree graph model, any hereditary property is testable if the input graph belongs to a hereditary and non-expanding family of graphs.As an application, our result implies that, for example, any hereditary property (e.g., k-colorability, H-freeness, etc.) is testable in the bounded degree graph model for planar graphs, graphs with bounded genus, interval graphs, etc. No such results have been known before and prior to our work, in the bounded degree graph model very few graph properties have been known to be testable for any graph classes.
AU - Sohler, Christian
AU - Czumaj, Artur
ID - 18655
SN - 9780898716245
T2 - Proceedings of the 17th ACM-SIAM Symposium on Discrete Algorithms (SODA'07)
TI - On Testable Properties in Bounded Degree Graphs
ER -