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2005


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Grain-boundary melting phase transition in the Cu-Bi system

Divinski, S., Lohmann, M., Herzig, C., Straumal, B., Baretzky, B., Gust, W.

{Physical Review B}, 71, 2005 (article)

mms

[BibTex]

2005


[BibTex]


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A fast ab initio approach to the simulation of spin dynamics

Fähnle, M., Drautz, R., Singer, R., Steiauf, D., Berkov, D. V.

{Computational Materials Science}, 32, pages: 118-122, 2005 (article)

mms

[BibTex]

[BibTex]


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Hydrogen adsorption in different carbon nanostructures

Panella, B., Hirscher, M., Roth, S.

{Carbon}, 43, pages: 2209-2214, 2005 (article)

mms

[BibTex]

[BibTex]


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A dynamical systems approach to learning: a frequency-adaptive hopper robot

Buchli, J., Righetti, L., Ijspeert, A.

In Proceedings of the VIIIth European Conference on Artificial Life ECAL 2005, pages: 210-220, Springer Verlag, 2005 (inproceedings)

mg

[BibTex]

[BibTex]


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From Dynamic Hebbian Learning for Oscillators to Adaptive Central Pattern Generators

Righetti, L., Buchli, J., Ijspeert, A.

In Proceedings of 3rd International Symposium on Adaptive Motion in Animals and Machines – AMAM 2005, Verlag ISLE, Ilmenau, 2005 (inproceedings)

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[BibTex]

[BibTex]


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A new methodology for robot control design

Peters, J., Mistry, M., Udwadia, F. E., Schaal, S.

In The 5th ASME International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC 2005), Long Beach, CA, Sept. 24-28, 2005, clmc (inproceedings)

Abstract
Gauss principle of least constraint and its generalizations have provided a useful insights for the development of tracking controllers for mechanical systems (Udwadia,2003). Using this concept, we present a novel methodology for the design of a specific class of robot controllers. With our new framework, we demonstrate that well-known and also several novel nonlinear robot control laws can be derived from this generic framework, and show experimental verifications on a Sarcos Master Arm robot for some of these controllers. We believe that the suggested approach unifies and simplifies the design of optimal nonlinear control laws for robots obeying rigid body dynamics equations, both with or without external constraints, holonomic or nonholonomic constraints, with over-actuation or underactuation, as well as open-chain and closed-chain kinematics.

am

link (url) [BibTex]

link (url) [BibTex]


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Geckobot and waalbot: Small-scale wall climbing robots

Unver, O., Murphy, M., Sitti, M.

In Infotech@ Aerospace, pages: 6940, 2005 (incollection)

pi

[BibTex]

[BibTex]


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Fusion of biomedical microcapsule endoscope and microsystem technology

Kim, Tae Song, Kim, Byungkyu, Cho, Dongil Dan, Song, Si Young, Dario, P, Sitti, M

In Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS’05. The 13th International Conference on, 1, pages: 9-14, 2005 (inproceedings)

pi

[BibTex]

[BibTex]


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Atomic force microscope based two-dimensional assembly of micro/nanoparticles

Tafazzoli, A., Pawashe, C., Sitti, M.

In Assembly and Task Planning: From Nano to Macro Assembly and Manufacturing, 2005.(ISATP 2005). The 6th IEEE International Symposium on, pages: 230-235, 2005 (inproceedings)

pi

[BibTex]

[BibTex]


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Synthesis of the nanocrystalline MgS and its interaction with hydrogen

Goo, N. H., Hirscher, M.

{Journal of Alloys and Compounds}, 404, pages: 503-506, 2005 (article)

mms

[BibTex]

[BibTex]


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Time-scales of electronic processes in Fe3O4 - An attempt to resolve a recently accentuated controversy

Fähnle, M., Kronmüller, H., Walz, F.

{Physica B}, 369, pages: 177-180, 2005 (article)

mms

[BibTex]

[BibTex]


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Bending of magnetic avalanches in MgB2 thin films

Albrecht, J., Matveev, A., Djupmyr, M., Schütz, G., Stuhlhofer, B., Habermeier, H.

{Applied Physics Letters}, 87, 2005 (article)

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[BibTex]

[BibTex]


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Magnetic pinning of flux lines in heterostructures of cuprates and manganites

Albrecht, J., Soltan, S., Habermeier, H.-U.

{Physical Review B}, 72, 2005 (article)

mms

[BibTex]

[BibTex]


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On the pair-potential modelling of alloy surfaces

Drautz, R., Fähnle, M.

{Surface Science}, 585, pages: 108-112, 2005 (article)

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[BibTex]

[BibTex]


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Crystal field parameters at the (0001) surface of rare-earth metals: an ab initio study

Welsch, F., Fähnle, M., Jensen, P. J.

{Journal of Physics: Condensed Matter}, 17, pages: 2061-2072, 2005 (article)

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[BibTex]

[BibTex]


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Spatially resolved ferromagnetic resonance: Imaging of ferromagnetic eigenmodes

Puzic, A., Van Waeyenberge, B., Chou, K. W., Fischer, P., Stoll, H., Schütz, G., Tyliszczak, T., Rott, K., Brückl, H., Reiss, G., Neudecker, I., Haug, T., Buess, M., Back, C. H.

{Journal of Applied Physics}, 97, 2005 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Defects distribution of Pr2Fe14B hard magnetic magnet from amorphous to nanostructures characterized by positron annihilation spectroscopy

Wu, Y. C., Sprengel, W., Reimann, K., Reichle, K. J., Goll, D., Würschum, R., Schaefer, H. E.

In PRICM 5. Proceedings of the Fifth Pacific RIM International Conference on Advanced Materials and Processing, 475-479, pages: 2123-2126, Materials Science Forum, Trans Tech, Beijing, China, 2005 (inproceedings)

mms

[BibTex]

[BibTex]


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Implementing sub-ns time resolution into magnetic X-ray microscopies

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

In T115, pages: 1029-1031, Malmö/Lund, Sweden, 2005 (inproceedings)

mms

[BibTex]

[BibTex]


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Proton magnetic resonance spectra of YH3 and LuH3

Brady, S. K., Conradi, M. S., Majer, G., Barnes, R. G.

{Physical Review B}, 72, 2005 (article)

mms

[BibTex]

[BibTex]


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Hydrogen storage in spherical nanoporous carbons

Terres, E., Panella, B., Hayashi, T., Kim, Y. A., Endo, M., Dominguez, J. M., Hirscher, M., Terrones, H., Terrones, H.

{Chemical Physics Letters}, 403(4-6):363-366, 2005 (article)

mms

[BibTex]

[BibTex]


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Faceting and migration of twin grain boundaries in zinc

Straumal, B. B., Rabkin, E., Sursaeva, V. G., Goruakova, A. S.

{Zeitschrift f\"ur Metallkunde}, 96(2):161-166, 2005 (article)

mms

[BibTex]

[BibTex]


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Arm movement experiments with joint space force fields using an exoskeleton robot

Mistry, M., Mohajerian, P., Schaal, S.

In IEEE Ninth International Conference on Rehabilitation Robotics, pages: 408-413, Chicago, Illinois, June 28-July 1, 2005, clmc (inproceedings)

Abstract
A new experimental platform permits us to study a novel variety of issues of human motor control, particularly full 3-D movements involving the major seven degrees-of-freedom (DOF) of the human arm. We incorporate a seven DOF robot exoskeleton, and can minimize weight and inertia through gravity, Coriolis, and inertia compensation, such that subjects' arm movements are largely unaffected by the manipulandum. Torque perturbations can be individually applied to any or all seven joints of the human arm, thus creating novel dynamic environments, or force fields, for subjects to respond and adapt to. Our first study investigates a joint space force field where the shoulder velocity drives a disturbing force in the elbow joint. Results demonstrate that subjects learn to compensate for the force field within about 100 trials, and from the strong presence of aftereffects when removing the field in some randomized catch trials, that an inverse dynamics, or internal model, of the force field is formed by the nervous system. Interestingly, while post-learning hand trajectories return to baseline, joint space trajectories remained changed in response to the field, indicating that besides learning a model of the force field, the nervous system also chose to exploit the space to minimize the effects of the force field on the realization of the endpoint trajectory plan. Further applications for our apparatus include studies in motor system redundancy resolution and inverse kinematics, as well as rehabilitation.

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link (url) [BibTex]

link (url) [BibTex]


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A unifying framework for the control of robotics systems

Peters, J., Mistry, M., Udwadia, F. E., Cory, R., Nakanishi, J., Schaal, S.

In IEEE International Conference on Intelligent Robots and Systems (IROS 2005), pages: 1824-1831, Edmonton, Alberta, Canada, Aug. 2-6, 2005, clmc (inproceedings)

Abstract
Recently, [1] suggested to derive tracking controllers for mechanical systems using a generalization of GaussÕ principle of least constraint. This method al-lows us to reformulate control problems as a special class of optimal control. We take this line of reasoning one step further and demonstrate that well-known and also several novel nonlinear robot control laws can be derived from this generic methodology. We show experimental verifications on a Sar-cos Master Arm robot for some of the the derived controllers.We believe that the suggested approach offers a promising unification and simplification of nonlinear control law design for robots obeying rigid body dynamics equa-tions, both with or without external constraints, with over-actuation or under-actuation, as well as open-chain and closed-chain kinematics.

am

link (url) [BibTex]

link (url) [BibTex]


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A new endoscopic microcapsule robot using beetle inspired microfibrillar adhesives

Cheung, E., Karagozler, M. E., Park, S., Kim, B., Sitti, M.

In Advanced Intelligent Mechatronics. Proceedings, 2005 IEEE/ASME International Conference on, pages: 551-557, 2005 (inproceedings)

pi

Project Page [BibTex]

Project Page [BibTex]


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Learning to Feel the Physics of a Body

Der, R., Hesse, F., Martius, G.

In Computational Intelligence for Modelling, Control and Automation, CIMCA 2005 , 2, pages: 252-257, Washington, DC, USA, 2005 (inproceedings)

Abstract
Despite the tremendous progress in robotic hardware and in both sensorial and computing efficiencies the performance of contemporary autonomous robots is still far below that of simple animals. This has triggered an intensive search for alternative approaches to the control of robots. The present paper exemplifies a general approach to the self-organization of behavior which has been developed and tested in various examples in recent years. We apply this approach to an underactuated snake like artifact with a complex physical behavior which is not known to the controller. Due to the weak forces available, the controller so to say has to develop a kind of feeling for the body which is seen to emerge from our approach in a natural way with meandering and rotational collective modes being observed in computer simulation experiments.

al

[BibTex]

[BibTex]


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Nanostructures with high surface area for hydrogen storage

Hirscher, M., Panella, B.

{Journal of Alloys and Compounds}, 404, pages: 399-401, 2005 (article)

mms

[BibTex]

[BibTex]


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Timescale settling and nature of electron transport in magnetite - General considerations in view of new magnetic after-effect results on dilutely Ti4+-doped Fe3O4

Walz, F., Brabers, V. A. M., Brabers, J. H. V. J., Kronmüller, H.

{Journal of Physics: Condensed Matter}, 17(42):6763-6781, 2005 (article)

mms

[BibTex]

[BibTex]


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Topological k-space refinement of the configurational energy of alloys

Shchyglo, O., Bugaev, V. N., Drautz, R., Udyansky, A., Reichert, H., Dosch, H.

{Physical Review B}, 72(14), 2005 (article)

mms

[BibTex]

[BibTex]


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Large surface area nanostructures for hydrogen storage

Hirscher, M., Panella, B.

{Annales de Chimie}, 30(5):519-529, 2005 (article)

mms

[BibTex]

[BibTex]


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Electronic and magnetic properties of ligand-free FePt nanoparticles

Boyen, H., Fauth, K., Stahl, B., Ziemann, P., Kästle, G., Weigl, F., Banhart, F., He\ssler, M., Schütz, G., Gajbhiye, N. S., Ellrich, J., Hahn, H., Büttner, M., Garnier, M. G., Oelhafen, P.

{Advanced Materials}, 17(5):574-578, 2005 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Identification of extrinsic Mn contributions in Ga1-xMnxAs by field-dependent magnetic circular X-ray dichroism

Rader, O., Fauth, K., Gould, C., Rüster, C., Schott, G. M., Schmidt, G., Brunner, K., Molenkamp, L. W., Schütz, G., Kronast, F., Dürr, H. A., Eberhardt, W., Gudat, W.

{Journal of Electron Spectroscopy and Related Phenomena}, 144(Sp. issue):789-792, 2005 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Fundamentals of interface phenomena in advanced bulk nanoscale materials

Baretzky, B., Baró, M. D., Grabovetskaya, G. P., Gubicza, J., Ivanov, M. B., Kolobov, Y. R., Langdon, T. G., Lendvai, J., Lipnitskii, A. G., Mazilkin, A. A., Nazarov, A. A., Nogués, J., Ovidko, I. A., Protasova, S. G., Raab, G. I., Révész, Á., Skiba, N. V., Sort, J., Starink, M. J., Straumal, B. B., Suriñach, S., Ungár, T., Zhilyaev, A. P.

{Reviews on Advanced Materials Science}, 9(1):45-108, 2005 (article)

mms

[BibTex]

[BibTex]


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Formation of nanostructure during high-pressure torsion of Al-Zn, Al-Mg and Al-Zn-Mg alloys

Mazilkin, A. A., Kogtenkova, O. A., Straumal, B. B., Ruslan, Z, Valiev, Z., Baretzky, B.

{Defect and Diffusion Forum}, 237-240, pages: 739-744, 2005 (article)

mms

[BibTex]

[BibTex]


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Micromagnetic simulation as a bridge between magnetic-force and magnetic-transmission X-ray microscopy

Bolte, M., Eiselt, R., Eimüller, T.

{Journal of Magnetism and Magnetic Materials}, 290, pages: 723-726, 2005 (article)

mms

[BibTex]

[BibTex]


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Grain-boundary melting phase transition in the Cu-Bi system

Divinski, S., Lohmann, M., Herzig, C., Straumal, B., Baretzky, B., Gust, W.

{Physical Review B}, 71, 2005 (article)

mms

[BibTex]

[BibTex]

1996


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A kendama learning robot based on a dynamic optimiation principle

Miyamoto, H., Gandolfo, F., Gomi, H., Schaal, S., Koike, Y., Rieka, O., Nakano, E., Wada, Y., Kawato, M.

In Preceedings of the International Conference on Neural Information Processing, pages: 938-942, Hong Kong, September 1996, clmc (inproceedings)

am

[BibTex]

1996


[BibTex]


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Incorporating invariances in support vector learning machines

Schölkopf, B., Burges, C., Vapnik, V.

In Artificial Neural Networks: ICANN 96, LNCS vol. 1112, pages: 47-52, (Editors: C von der Malsburg and W von Seelen and JC Vorbrüggen and B Sendhoff), Springer, Berlin, Germany, 6th International Conference on Artificial Neural Networks, July 1996, volume 1112 of Lecture Notes in Computer Science (inproceedings)

Abstract
Developed only recently, support vector learning machines achieve high generalization ability by minimizing a bound on the expected test error; however, so far there existed no way of adding knowledge about invariances of a classification problem at hand. We present a method of incorporating prior knowledge about transformation invariances by applying transformations to support vectors, the training examples most critical for determining the classification boundary.

ei

PDF DOI [BibTex]

PDF DOI [BibTex]


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A Kendama learning robot based on bi-directional theory

Miyamoto, H., Schaal, S., Gandolfo, F., Koike, Y., Osu, R., Nakano, E., Wada, Y., Kawato, M.

Neural Networks, 9(8):1281-1302, 1996, clmc (article)

Abstract
A general theory of movement-pattern perception based on bi-directional theory for sensory-motor integration can be used for motion capture and learning by watching in robotics. We demonstrate our methods using the game of Kendama, executed by the SARCOS Dextrous Slave Arm, which has a very similar kinematic structure to the human arm. Three ingredients have to be integrated for the successful execution of this task. The ingredients are (1) to extract via-points from a human movement trajectory using a forward-inverse relaxation model, (2) to treat via-points as a control variable while reconstructing the desired trajectory from all the via-points, and (3) to modify the via-points for successful execution. In order to test the validity of the via-point representation, we utilized a numerical model of the SARCOS arm, and examined the behavior of the system under several conditions.

am

link (url) [BibTex]

link (url) [BibTex]


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From isolation to cooperation: An alternative of a system of experts

Schaal, S., Atkeson, C. G.

In Advances in Neural Information Processing Systems 8, pages: 605-611, (Editors: Touretzky, D. S.;Mozer, M. C.;Hasselmo, M. E.), MIT Press, Cambridge, MA, 1996, clmc (inbook)

Abstract
We introduce a constructive, incremental learning system for regression problems that models data by means of locally linear experts. In contrast to other approaches, the experts are trained independently and do not compete for data during learning. Only when a prediction for a query is required do the experts cooperate by blending their individual predictions. Each expert is trained by minimizing a penalized local cross validation error using second order methods. In this way, an expert is able to adjust the size and shape of the receptive field in which its predictions are valid, and also to adjust its bias on the importance of individual input dimensions. The size and shape adjustment corresponds to finding a local distance metric, while the bias adjustment accomplishes local dimensionality reduction. We derive asymptotic results for our method. In a variety of simulations we demonstrate the properties of the algorithm with respect to interference, learning speed, prediction accuracy, feature detection, and task oriented incremental learning. 

am

link (url) [BibTex]

link (url) [BibTex]


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One-handed juggling: A dynamical approach to a rhythmic movement task

Schaal, S., Sternad, D., Atkeson, C. G.

Journal of Motor Behavior, 28(2):165-183, 1996, clmc (article)

Abstract
The skill of rhythmic juggling a ball on a racket is investigated from the viewpoint of nonlinear dynamics. The difference equations that model the dynamical system are analyzed by means of local and non-local stability analyses. These analyses yield that the task dynamics offer an economical juggling pattern which is stable even for open-loop actuator motion. For this pattern, two types of pre dictions are extracted: (i) Stable periodic bouncing is sufficiently characterized by a negative acceleration of the racket at the moment of impact with the ball; (ii) A nonlinear scaling relation maps different juggling trajectories onto one topologically equivalent dynamical system. The relevance of these results for the human control of action was evaluated in an experiment where subjects performed a comparable task of juggling a ball on a paddle. Task manipulations involved different juggling heights and gravity conditions of the ball. The predictions were confirmed: (i) For stable rhythmic performance the paddle's acceleration at impact is negative and fluctuations of the impact acceleration follow predictions from global stability analysis; (ii) For each subject, the realizations of juggling for the different experimental conditions are related by the scaling relation. These results allow the conclusion that for the given task, humans reliably exploit the stable solutions inherent to the dynamics of the task and do not overrule these dynamics by other control mechanisms. The dynamical scaling serves as an efficient principle to generate different movement realizations from only a few parameter changes and is discussed as a dynamical formalization of the principle of motor equivalence.

am

link (url) [BibTex]

link (url) [BibTex]

1995


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A kendama learning robot based on a dynamic optimization theory

Miyamoto, H., Gandolfo, F., Gomi, H., Schaal, S., Koike, Y., Osu, R., Nakano, E., Kawato, M.

In Preceedings of the 4th IEEE International Workshop on Robot and Human Communication (RO-MAN’95), pages: 327-332, Tokyo, July 1995, clmc (inproceedings)

am

[BibTex]

1995


[BibTex]


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Visual tracking for moving multiple objects: an integration of vision and control

Sitti, M, Bozma, I, Denker, A

In Industrial Electronics, 1995. ISIE’95., Proceedings of the IEEE International Symposium on, 2, pages: 535-540, 1995 (inproceedings)

pi

[BibTex]

[BibTex]


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Batting a ball: Dynamics of a rhythmic skill

Sternad, D., Schaal, S., Atkeson, C. G.

In Studies in Perception and Action, pages: 119-122, (Editors: Bardy, B.;Bostma, R.;Guiard, Y.), Erlbaum, Hillsdayle, NJ, 1995, clmc (inbook)

am

[BibTex]

[BibTex]


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Memory-based neural networks for robot learning

Atkeson, C. G., Schaal, S.

Neurocomputing, 9, pages: 1-27, 1995, clmc (article)

Abstract
This paper explores a memory-based approach to robot learning, using memory-based neural networks to learn models of the task to be performed. Steinbuch and Taylor presented neural network designs to explicitly store training data and do nearest neighbor lookup in the early 1960s. In this paper their nearest neighbor network is augmented with a local model network, which fits a local model to a set of nearest neighbors. This network design is equivalent to a statistical approach known as locally weighted regression, in which a local model is formed to answer each query, using a weighted regression in which nearby points (similar experiences) are weighted more than distant points (less relevant experiences). We illustrate this approach by describing how it has been used to enable a robot to learn a difficult juggling task. Keywords: memory-based, robot learning, locally weighted regression, nearest neighbor, local models.

am

link (url) [BibTex]

link (url) [BibTex]

1991


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Ways to smarter CAD-systems

Ehrlenspiel, K., Schaal, S.

In Proceedings of ICED’91Heurista, pages: 10-16, (Editors: Hubka), Edition, Schriftenreihe WDK 21. Zürich, 1991, clmc (inbook)

am

[BibTex]

1991


[BibTex]