Header logo is


2004


no image
Interaction of hydrogen isotopes with carbon nanostructures

Haluska, M., Hirscher, M., Becher, M., Dettlaff-Weglikowska, U., Chen, X., Roth, S.

{Materials Science and Engineering B}, 108, pages: 130-133, 2004 (article)

mms

[BibTex]

2004


[BibTex]


no image
Formation of nanograined structure and decomposition of supersaturated solid solution during high pressure torsion of Al-Zn and Al-Mg alloys

Straumal, B. B., Baretzky, B., Mazilkin, A. A., Phillipp, F., Kogtenkova, O. A., Volkov, M. N., Valiev, R. Z.

{Acta Materialia}, 52, pages: 4469-4478, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Ab-initio modeling of nonlinear magnetoelastic coupling in epitaxial films

Komelj, M., Fähnle, M.

{Journal of Magnetism and Magnetic Materials}, 272-276, pages: e1587-e1588, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Modern nanocrystalline/nanostructured hard magnetic materials

Kronmüller, H., Goll, D.

In 272-276, pages: e319-e320, Rome [Italy], 2004 (inproceedings)

mms

[BibTex]

[BibTex]


no image
Modern nanostructured high-temperature permanent magnets

Goll, D., Kronmüller, H., Stadelmaier, H. H.

In Proceedings of the 18th International Workshop on Rare-Earth Magnets and their Applications, pages: 578-583, Laboratoire de Cristallographie/Laboratoire Louis Néel, CNRS, Grenoble, 2004 (inproceedings)

mms

[BibTex]

[BibTex]


no image
A framework for learning biped locomotion with dynamic movement primitives

Nakanishi, J., Morimoto, J., Endo, G., Cheng, G., Schaal, S., Kawato, M.

In IEEE-RAS/RSJ International Conference on Humanoid Robots (Humanoids 2004), IEEE, Los Angeles, CA: Nov.10-12, Santa Monica, CA, 2004, clmc (inproceedings)

Abstract
This article summarizes our framework for learning biped locomotion using dynamical movement primitives based on nonlinear oscillators. Our ultimate goal is to establish a design principle of a controller in order to achieve natural human-like locomotion. We suggest dynamical movement primitives as a central pattern generator (CPG) of a biped robot, an approach we have previously proposed for learning and encoding complex human movements. Demonstrated trajectories are learned through movement primitives by locally weighted regression, and the frequency of the learned trajectories is adjusted automatically by a frequency adaptation algorithm based on phase resetting and entrainment of coupled oscillators. Numerical simulations and experimental implementation on a physical robot demonstrate the effectiveness of the proposed locomotion controller. Furthermore, we demonstrate that phase resetting contributes to robustness against external perturbations and environmental changes by numerical simulations and experiments.

am

link (url) [BibTex]

link (url) [BibTex]


no image
Learning Motor Primitives with Reinforcement Learning

Peters, J., Schaal, S.

In Proceedings of the 11th Joint Symposium on Neural Computation, http://resolver.caltech.edu/CaltechJSNC:2004.poster020, 2004, clmc (inproceedings)

Abstract
One of the major challenges in action generation for robotics and in the understanding of human motor control is to learn the "building blocks of move- ment generation," or more precisely, motor primitives. Recently, Ijspeert et al. [1, 2] suggested a novel framework how to use nonlinear dynamical systems as motor primitives. While a lot of progress has been made in teaching these mo- tor primitives using supervised or imitation learning, the self-improvement by interaction of the system with the environment remains a challenging problem. In this poster, we evaluate different reinforcement learning approaches can be used in order to improve the performance of motor primitives. For pursuing this goal, we highlight the difficulties with current reinforcement learning methods, and line out how these lead to a novel algorithm which is based on natural policy gradients [3]. We compare this algorithm to previous reinforcement learning algorithms in the context of dynamic motor primitive learning, and show that it outperforms these by at least an order of magnitude. We demonstrate the efficiency of the resulting reinforcement learning method for creating complex behaviors for automous robotics. The studied behaviors will include both discrete, finite tasks such as baseball swings, as well as complex rhythmic patterns as they occur in biped locomotion

am

[BibTex]

[BibTex]


no image
Atomic force microscope probe based controlled pushing for nanotribological characterization

Sitti, M.

IEEE/ASME Transactions on mechatronics, 9(2):343-349, IEEE, 2004 (article)

pi

[BibTex]

[BibTex]


no image
Dynamic behavior and simulation of nanoparticle sliding during nanoprobe-based positioning

Tafazzoli, A., Sitti, M.

In Proc. ASME International Mechanical Engineering Conference, 19, pages: 32, 2004 (inproceedings)

pi

[BibTex]

[BibTex]


no image
Effective exchange interaction in a quasi-two-dimensional self-assembled nanoparticle array

Wiedwald, U., Cerchez, M., Farle, M., Fauth, K., Schütz, G., Zürn, K., Boyen, H., Ziemann, P.

{Physical Review B}, 70, 2004 (article)

mms

DOI [BibTex]

DOI [BibTex]


no image
How well does total electron yield measure x-ray absorption in nanoparticles?

Fauth, K.

{Applied Physics Letters}, 85(15):3271-3273, 2004 (article)

mms

DOI [BibTex]

DOI [BibTex]


no image
Ordering and magnetism in Fe-Co: Dense sequence of ground-state structures

Drautz, R., Diaz-Ortiz, A., Fähnle, M., Dosch, H.

{Physical Review Letters}, 93(6), 2004 (article)

mms

[BibTex]

[BibTex]


no image
Thermal reversal of elongated ferromagnetic particles misoriented to the applied field

Goll, D., Bertram, H. N.

{IEEE Transactions on Magnetics}, 40(4):2416-2418, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Anisotropy of the orbital moments and the magnetic dipole term Tz in CrO2: An ab-initio study

Komelj, M., Ederer, C., Fähnle, M.

{Physical Review B}, 69, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Imaging sub-ns spin dynamics in magnetic nanostructures with magnetic transmission X-ray microscopy

Fischer, P., Stoll, H., Puzic, A., Van Waeyenberge, B., Raabe, J., Haug, T., Denbeaux, G., Pearson, A., Höllinger, R., Back, C. H., Weiss, D., Schütz, G.

In Synchrotron Radiation Instrumentation, 705, pages: 1291-1294, AIP Conference Proceedings, American Institute of Physics, San Francisco, California (USA), 2004 (inproceedings)

mms

[BibTex]

[BibTex]


no image
Modern nanostructured high-temperature permanent magnets

Goll, D., Kronmüller, H., Stadelmaier, H. H.

In Proceedings of the 18th International Workshop on Rare-Earth Magnets and their Applications, pages: 578-583, Laboratoire de Cristallographie/Laboratoire Louis Néel, CNRS, Grenoble, 2004 (inproceedings)

mms

[BibTex]

[BibTex]


no image
Existence of transient temperature spike induced by SHI: evidence by ion beam analysis

Avasthi, D. K., Ghosh, S., Srivastava, S. K., Assmann, W.

In 219-220, pages: 206-214, Albuquerque, NM [USA], 2004 (inproceedings)

mms

[BibTex]

[BibTex]


no image
Core-shell iron-iron oxide nanoparticles: magnetic properties and interactions

Theil-Kuhn, L., Bojesen, A., Timmermann, L., Fauth, K., Goering, E. J., Johnson, E., Meedom Nielsen, M., Morup, S.

{Journal of Magnetism and Magnetic Materials}, 272-276, pages: 1485-1486, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Measurement of very low bulk concentrations (below 1 atppm) of hydrogen using ERDA

Tripathi, A., Kruse, O., Carstanjen, H. D.

{Nuclear Instruments and Methods B}, 219-220, pages: 435-439, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Three-dimensional nanoscale manipulation and manufacturing using proximal probes: controlled pulling of polymer micro/nanofibers

Nain, A. S., Amon, C., Sitti, M.

In Mechatronics, 2004. ICM’04. Proceedings of the IEEE International Conference on, pages: 224-230, 2004 (inproceedings)

pi

[BibTex]

[BibTex]


no image
Unusual doublet structure in proton magnetic-resonance spectra of yttrium and lutetium trihydrides

Majer, G., Telfah, A., Grinberg, F., Barnes, R. G.

{Physical Review B}, 70(13), 2004 (article)

mms

[BibTex]

[BibTex]


no image
Kinetics of primary nanocrystallization in Al-rich metallic glass with quenched-in nuclei

Wang, J. Q., Zhang, H. W., Gu, X. J., Lu, K., Sommer, F., Mittemeijer, E.

{Materials Science and Engineering A}, 375-377, pages: 980-984, 2004 (article)

mms

[BibTex]

[BibTex]


no image
3-dimensional Wulff diagrams for \Sigma3 grain boundaries in Cu

Straumal, B., Kucherinenko, Y., Baretzky, B.

{Reviews on Advanced Materials Science}, 7(1):23-31, 2004 (article)

mms

[BibTex]

[BibTex]


no image
First-principles study of the interplay between magnetism and phase equilibria in Fe-Co systems

Diaz-Ortiz, A., Drautz, R., Fähnle, M., Dosch, H.

{Journal of Magnetism and Magnetic Materials}, 272-276, pages: 780-782, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Magnetic field optimization of permanent magnet unulators for arbitrary polarization

Bahrdt, J., Frentrup, W., Gaupp, A., Scheer, M., Englisch, U.

{Nuclear Instruments and Methods in Physics Research A}, 516, pages: 575-585, 2004 (article)

mms

[BibTex]

[BibTex]


no image
High-resolution imaging of fast magnetization dynamics in magnetic nanostructures

Stoll, H., Puzic, A., Van Waeyenberge, B., Fischer, P., Raabe, J., Buess, M., Haug, T., Höllinger, R., Back, C., Weiss, D., Denbeaux, G.

{Applied Physics Letters}, 84, pages: 3328-3330, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Comparison of low-temperature magnetic relaxations in two systems GdAl2Dx (C15 Laves phase) and Fe3O4 (Inverse spinel)

Walz, F., Reule, H., Hirscher, M., Kronmüller, H.

{Physica Status Solidi B}, 241(2):389-400, 2004 (article)

mms

[BibTex]

[BibTex]


no image
General relations between many-body potentials and cluster expansions in multi-component systems

Drautz, R., Fähnle, M., Sanchez, J.M.

{Journal of Physics: Condensed Matter}, 16, pages: 3843-3852, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Counting individual atom layers in graphite - high-resolution RBS experiments on HOPG (highly ordered pyrolytic graphite)

Srivastava, S. K., Plachke, D., Szökefalvi-Nagy, A., Major, J., Carstanjen, H. D.

{Nuclear Instruments and Methods B}, 219-220, pages: 364-368, 2004 (article)

Abstract
{The paper reports about recent experiments on HOPG (highly oriented pyrolytic graphite) by high-resolution RBS (Rutherford backscattering spectroscopy). By using an ion beam of 1 MeV N+ up to 7 individual monolayers could be identified in the RBS spectrum from such a sample. This is about twice as much as observed by other groups up to now. Since close to the surface the RBS peaks from the individual carbon layers are well separated, various quantities important for the ion-solid interaction can be determined with high precision, such as the stopping power of 1 MeV N ions in graphite and their energy straggling. Close to the surface the RBS peaks are asymmetric which is well explained in the framework of the Landau theory of energy straggling.}

mms

[BibTex]

[BibTex]


no image
Feedback error learning and nonlinear adaptive control

Nakanishi, J., Schaal, S.

Neural Networks, 17(10):1453-1465, 2004, clmc (article)

Abstract
In this paper, we present our theoretical investigations of the technique of feedback error learning (FEL) from the viewpoint of adaptive control. We first discuss the relationship between FEL and nonlinear adaptive control with adaptive feedback linearization, and show that FEL can be interpreted as a form of nonlinear adaptive control. Second, we present a Lyapunov analysis suggesting that the condition of strictly positive realness (SPR) associated with the tracking error dynamics is a sufficient condition for asymptotic stability of the closed-loop dynamics. Specifically, for a class of second order SISO systems, we show that this condition reduces to KD^2 > KP; where KP and KD are positive position and velocity feedback gains, respectively. Moreover, we provide a ÔpassivityÕ-based stability analysis which suggests that SPR of the tracking error dynamics is a necessary and sufficient condition for asymptotic hyperstability. Thus, the condition KD^2>KP mentioned above is not only a sufficient but also necessary condition to guarantee asymptotic hyperstability of FEL, i.e. the tracking error is bounded and asymptotically converges to zero. As a further point, we explore the adaptive control and FEL framework for feedforward control formulations, and derive an additional sufficient condition for asymptotic stability in the sense of Lyapunov. Finally, we present numerical simulations to illustrate the stability properties of FEL obtained from our mathematical analysis.

am

link (url) [BibTex]

link (url) [BibTex]


no image
Micro-and nano-scale robotics

Sitti, M.

In American Control Conference, 2004. Proceedings of the 2004, 1, pages: 1-8, 2004 (inproceedings)

pi

[BibTex]

[BibTex]


no image
Gecko inspired surface climbing robots

Menon, C., Murphy, M., Sitti, M.

In Robotics and Biomimetics, 2004. ROBIO 2004. IEEE International Conference on, pages: 431-436, 2004 (inproceedings)

pi

Project Page [BibTex]

Project Page [BibTex]


no image
Micromagnetism and the microstructure of high-temperature permanent magnets

Goll, D., Kronmüller, H., Stadelmaier, H. H.

{Journal of Applied Physics}, 96(11):6534-6545, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Atomic defects and diffusion in intermetallic compounds with DO3 structure: An ab-initio study

Fähnle, M., Schimmele, L.

{Zeitschrift f\"ur Metallkunde}, 95, pages: 864-869, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Cluster surface interactions: Small Fe clusters driven nonmagnetic on graphite

Fauth, K., Gold, S., He\ssler, M., Schütz, G.

{Chemical Physics Letters}, 392(4-6):498-502, 2004 (article)

mms

DOI [BibTex]

DOI [BibTex]


no image
\textquotesingleWetting by solid state’grain boundary phase transition in Zn-Al alloys

Straumal, B. B., Khruzhcheva, A. S., Lopez, G. A.

{Reviews on Advanced Materials Science}, 7(1):13-22, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Two prototypes of metal adatom configurations on Mo(112): an ab initio study for Li and Co

Singer, R., Drautz, R., Fähnle, M.

{Surface Science}, 559, pages: 241-248, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Grain boundary phase transitions and their influence on properties of polycrystals

Straumal, B., Baretzky, B.

{Interface Science}, 12(2-3):147-155, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Hard magnetic hollow nanospheres

Goll, D., Berkowitz, A. E., Bertram, H. N.

In Proceedings of the 18th International Workshop on Rare-Earth Magnets and their Applications, pages: 704-707, Laboratoire de Cristallographie/Laboratoire Louis Neel, CNRS, Grenoble, 2004 (inproceedings)

mms

[BibTex]

[BibTex]


no image
Swift heavy ion induced modification of Si/C60 multilayers

Srivastava, S. K., Kabiraj, D., Schattat, B., Carstanjen, H. D., Avasthi, D. K.

{Nuclear Instruments and Methods in Physics Research B}, 219 - 220, pages: 815-819, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Static displacements of Pd in the solid solution PdBy (0\textlessy\textless0.2) as determined by neutron diffraction

Berger, T. G., Leineweber, A., Mittemeijer, E. J., Fischer, P.

{Physica Status Solidi (A)}, 201, pages: 1484-1492, 2004 (article)

mms

[BibTex]

[BibTex]


no image
X-MCD magnetometry of CMR perovskites La0.67-yREyCa0.33MnO3

Sikora, M., Kapusta, C., Zajac, D., Tokarz, W., Oates, C. J., Borowiec, M., Rybicki, D., Goering, E. J., Fischer, P., Schütz, G., De Teresa, J. M., Ibarra, M. R.

{Journal of Magnetism and Magnetic Materials}, 272-276, pages: 2148-2150, 2004 (article)

mms

[BibTex]

[BibTex]


no image
Critical thicknesses of domain formations in cubic particles and thin films

Kronmüller, H., Goll, D., Hertel, R., Schütz, G.

{Physica B}, 343(1-4):229-235, 2004 (article)

mms

[BibTex]

[BibTex]