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2008


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Epitaxial growth and properties of (001)-oriented TbBaCo2O6-αfilms

Kasper, N. V., Wochner, P., Vigliante, A., Dosch, H., Jakob, G., Carstanjen, H. D., Kremer, R. K.

{Journal of Applied Physics}, 103, 2008 (article)

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DOI [BibTex]

2008


DOI [BibTex]


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Magnetic properties of exchange-coupled L10-FePt/Fe composite elements

Goll, D., Breitling, A., Macke, S.

{IEEE Transactions on Magnetics}, 44(11):3472-3475, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Colloidal cobalt-doped ZnO nanorods: synthesis, structural, and magnetic properties

Büsgen, T., Hilgendorff, M., Irsen, S., Wilhelm, F., Rogalev, A., Goll, D., Giersig, M.

{Journal of Physical Chemistry C}, 112(7):2412-2417, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Raman studies of hydrogen adsorbed on nanostructured porous materials

Panella, B., Hirscher, M.

{Physical Chemistry Chemical Physics}, 10, pages: 2910-2917, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Thermal evolution and grain boundary phase transformations in severely deformed nanograined Al-Zn alloys

Straumal, B., Valiev, R., Kogtenkova, O., Zieba, P., Czeppe, T., Bielanska, E., Faryna, M.

{Acta Materialia}, 56(20):6123-6131, 2008 (article)

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DOI [BibTex]

DOI [BibTex]


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Hydrogen storage properties of Pd nanoparticle/carbon template composites

Campesi, R., Cuevas, F., Gadiou, R., Leroy, E., Hirscher, M., Vix-Guterl, C., Latroche, M.

{Carbon}, 46, pages: 206-214, 2008 (article)

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DOI [BibTex]

DOI [BibTex]


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Reversible transformation of a grain-boundary facet into a rough-to-rough ridge in zinc

Straumal, B. B., Gornakova, A. S., Sursaeva, V. G.

{Philosophical Magazine Letters}, 88(1):27-36, 2008 (article)

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DOI [BibTex]

DOI [BibTex]


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A library for locally weighted projection regression

Klanke, S., Vijayakumar, S., Schaal, S.

Journal of Machine Learning Research, 9, pages: 623-626, 2008, clmc (article)

Abstract
In this paper we introduce an improved implementation of locally weighted projection regression (LWPR), a supervised learning algorithm that is capable of handling high-dimensional input data. As the key features, our code supports multi-threading, is available for multiple platforms, and provides wrappers for several programming languages.

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link (url) [BibTex]

link (url) [BibTex]


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Preface to the Journal of Micro-Nano Mechatronics

Dario, P., Fukuda, T., Sitti, M.

Journal of Micro-Nano Mechatronics, 4(1-2):1-1, Springer-Verlag, 2008 (article)

pi

[BibTex]

[BibTex]


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A legged anchoring mechanism for capsule endoscopes using micropatterned adhesives

Glass, P., Cheung, E., Sitti, M.

IEEE Transactions on Biomedical Engineering, 55(12):2759-2767, IEEE, 2008 (article)

pi

Project Page [BibTex]

Project Page [BibTex]


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GdFe-Multilagen zur Vergrö\sserung des magnetischen Vortexkerns

Sackmann, V.

Universität Stuttgart, Stuttgart, 2008 (mastersthesis)

mms

[BibTex]

[BibTex]


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Dissipative Magnetisierungsdynamik: Ein Zugang über die ab-initio Elektronentheorie

Steiauf, D.

Universität Stuttgart, Stuttgart, 2008 (phdthesis)

mms

[BibTex]

[BibTex]


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The hole is important! The quest for ferromagnetism in doped ZnO

Tietze, T., Gacic, M., Schütz, G., Jakob, G., Brück, S., Goering, E.

{BESSY Highlights 2007}, pages: 14-15, 2008 (article)

mms

[BibTex]

[BibTex]


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Limitations of a simple quantum mechanical model: Magnetic dichroism in a relativistic one-electron atom

Rodr\’\iguez, J. C., Kostoglou, C., Singer, R., Seib, J., Fähnle, M.

{Physica Status Solidi (B)}, 245(4):735-739, 2008 (article)

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DOI [BibTex]

DOI [BibTex]


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Impact of irradiation-induced point defects on electronically and ionically induced magnetic relaxation mechanisms in titano-magnetites

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

{Physica Status Solidi (A)}, 205(12):2934-2942, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Polarization selective magnetic vortex dynamics and core reversal in rotating magnetic fields

Curcic, M., van Waeyenberge, B., Vansteenkiste, A., Weigand, M., Sackmann, V., Stoll, H., Fähnle, M., Tyliszczak, T., Woltersdorf, G., Back, C. H., Schütz, G.

{Physical Review Letters}, 101, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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X-ray spectroscopic investigations of Zn0.94Co0.06O thin films

Mayer, G., Fonin, M., Voss, S., Rüdiger, U., Goering, E.

{IEEE Transactions on Magnetics}, 44(11):2700-2703, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Experimental realization of graded L10-FePt/Fe composite media with perpendicular magnetization

Goll, D., Breitling, A., Gu, L., van Aken, P. A., Sigle, W.

{Journal of Applied Physics}, 104, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Hard magnetic L10 FePt thin films and nanopatterns

Breitling, A., Goll, D.

{Journal of Magnetism and Magnetic Materials}, 320, pages: 1449-1456, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Spin-reorientation transition in Co/Pt multilayers on nanospheres

Eimüller, T., Ulbrich, T. C., Amaladass, E., Guhr, I. L., Tyliszczak, T., Albrecht, M.

{Physical Review B}, 77, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Non-destructive compositional analysis of historic organ reed pipes

Manescu, A., Fiori, F., Giuliani, A., Kardjilov, N., Kasztovszky, Z., Rustichelli, F., Straumal, B.

{Journal of Physics: Condensed Matter}, 20, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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An advanced magnetic reflectometer

Brück, S., Bauknecht, S., Ludescher, B., Goering, E., Schütz, G.

{Review of Scientific Instruments}, 79, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Optimization strategies in human reinforcement learning

Hoffmann, H., Theodorou, E., Schaal, S.

Advances in Computational Motor Control VII, Symposium at the Society for Neuroscience Meeting, Washington DC, 2008, 2008, clmc (article)

am

PDF [BibTex]

PDF [BibTex]


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Dynamic modeling of stick slip motion in an untethered magnetic microrobot

Pawashe, C., Floyd, S., Sitti, M.

Proceedings of Robotics: Science and Systems IV, Zurich, Switzerland, 2008 (article)

pi

[BibTex]

[BibTex]


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Frequency analysis with coupled nonlinear oscillators

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

Physica D: Nonlinear Phenomena, 237(13):1705-1718, August 2008 (article)

Abstract
We present a method to obtain the frequency spectrum of a signal with a nonlinear dynamical system. The dynamical system is composed of a pool of adaptive frequency oscillators with negative mean-field coupling. For the frequency analysis, the synchronization and adaptation properties of the component oscillators are exploited. The frequency spectrum of the signal is reflected in the statistics of the intrinsic frequencies of the oscillators. The frequency analysis is completely embedded in the dynamics of the system. Thus, no pre-processing or additional parameters, such as time windows, are needed. Representative results of the numerical integration of the system are presented. It is shown, that the oscillators tune to the correct frequencies for both discrete and continuous spectra. Due to its dynamic nature the system is also capable to track non-stationary spectra. Further, we show that the system can be modeled in a probabilistic manner by means of a nonlinear Fokker–Planck equation. The probabilistic treatment is in good agreement with the numerical results, and provides a useful tool to understand the underlying mechanisms leading to convergence.

mg

link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Röntgenzirkulardichroische Untersuchungen XMCD an FePt und Ferrit Nanopartikeln

Nolle, D.

Universität Stuttgart, Stuttgart, 2008 (mastersthesis)

mms

[BibTex]

[BibTex]


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Nanostructured biointerfaces for investigating cellular adhesion and differentiation

Gojak, C.

Universität Heidelberg, Heidelberg, 2008 (mastersthesis)

mms

[BibTex]

[BibTex]


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In situ observation of cracks in gold nano-interconnects on flexible substrates

Olliges, S., Gruber, P. A., Orso, S., Auzelyte, V., Ekinci, Y., Solak, H. H., Spolenak, R.

{Scripta Materialia}, 58(3):175-178, 2008 (article)

mms

[BibTex]

[BibTex]


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Transmission electron microscopy study of the intermixing of Fe-Pt multilayers

Kaiser, T., Sigle, W., Goll, D., Goo, N. H., Srot, V., van Aken, P. A., Detemple, E., Jäger, W.

{Journal of Applied Physics}, 103, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Spin state and orbita moments across the metal-insulator-transition of REBaCo2O5.5 investigated by XMCD

Lafkioti, M., Goering, E., Gold, S., Schütz, G., Barilo, S. N., Shiryaev, S. V., Bychkov, G. L., Lemmens, P., Hinkov, V., Deisenhofer, J., Loidl, A.

{New Journal of Physics}, 10, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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A crucial role for primary cilia in cortical morphogenesis

Willaredt, M. A., Hasenpusch-Theil, K., Gardner, H. A. R., Kitanovic, I., Hirschfeld-Warneken, V. C., Gojak, C. P., Gorgas, K., Bradford, C. L., Spatz, J. P., Wölfl, S., Theil, T., Tucker, K. L.

{The Journal of Neuroscience}, 28(48):12887-12900, 2008 (article)

mms

[BibTex]

[BibTex]


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Exchange coupled composite layers for magnetic recording

Goll, D., Macke, S., Kronmüller, H.

{Physica B}, 403, pages: 338-341, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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XMCD studies on Co and Li doped ZnO magnetic semiconductors

Tietze, T., Gacic, M., Schütz, G., Jakob, G., Brück, S., Goering, E.

{New Journal of Physics}, 10, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Desorption studies of hydrogen in metal-organic frameworks

Panella, B., Hönes, K., Müller, U., Trukhan, N., Schubert, M., Pütter, H., Hirscher, M.

{Angewandte Chemie International Edition}, 47, pages: 2138-2142, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Wetting transition of grain-boundary triple junctions

Straumal, B. B., Kogtenkova, O., Zieba, P.

{Acta Materialia}, 56, pages: 925-933, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Time-resolved X-ray microscopy of spin-torque-induced magnetic vortex gyration

Bolte, M., Meier, G., Krüger, B., Drews, A., Eiselt, R., Bocklage, L., Bohlens, S., Tyliszczak, T., Vansteenkiste, A., Van Waeyenberge, B., Chou, K. W., Puzic, A., Stoll, H.

{Physical Review Letters}, 100, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]


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The Gilbert equation revisited: anisotropic and nonlocal damping of magnetization dynamics

Fähnle, M., Steiauf, D., Seib, J.

{Journal of Physics D}, 41, 2008 (article)

mms

DOI [BibTex]

DOI [BibTex]

2007


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Reaction graph kernels for discovering missing enzymes in the plant secondary metabolism

Saigo, H., Hattori, M., Tsuda, K.

NIPS Workshop on Machine Learning in Computational Biology, December 2007 (talk)

Abstract
Secondary metabolic pathway in plant is important for finding druggable candidate enzymes. However, there are many enzymes whose functions are still undiscovered especially in organism-specific metabolic pathways. We propose reaction graph kernels for automatically assigning the EC numbers to unknown enzymatic reactions in a metabolic network. Experiments are carried out on KEGG/REACTION database and our method successfully predicted the first three digits of the EC number with 83% accuracy.We also exhaustively predicted missing enzymatic functions in the plant secondary metabolism pathways, and evaluated our results in biochemical validity.

ei

Web [BibTex]

2007


Web [BibTex]


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Positional Oligomer Importance Matrices

Sonnenburg, S., Zien, A., Philips, P., Rätsch, G.

NIPS Workshop on Machine Learning in Computational Biology, December 2007 (talk)

Abstract
At the heart of many important bioinformatics problems, such as gene finding and function prediction, is the classification of biological sequences, above all of DNA and proteins. In many cases, the most accurate classifiers are obtained by training SVMs with complex sequence kernels, for instance for transcription starts or splice sites. However, an often criticized downside of SVMs with complex kernels is that it is very hard for humans to understand the learned decision rules and to derive biological insights from them. To close this gap, we introduce the concept of positional oligomer importance matrices (POIMs) and develop an efficient algorithm for their computation. We demonstrate how they overcome the limitations of sequence logos, and how they can be used to find relevant motifs for different biological phenomena in a straight-forward way. Note that the concept of POIMs is not limited to interpreting SVMs, but is applicable to general k−mer based scoring systems.

ei

Web [BibTex]

Web [BibTex]


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Machine Learning Algorithms for Polymorphism Detection

Schweikert, G., Zeller, G., Weigel, D., Schölkopf, B., Rätsch, G.

NIPS Workshop on Machine Learning in Computational Biology, December 2007 (talk)

ei

Web [BibTex]

Web [BibTex]


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A Tutorial on Spectral Clustering

von Luxburg, U.

Statistics and Computing, 17(4):395-416, December 2007 (article)

Abstract
In recent years, spectral clustering has become one of the most popular modern clustering algorithms. It is simple to implement, can be solved efficiently by standard linear algebra software, and very often outperforms traditional clustering algorithms such as the k-means algorithm. On the first glance spectral clustering appears slightly mysterious, and it is not obvious to see why it works at all and what it really does. The goal of this tutorial is to give some intuition on those questions. We describe different graph Laplacians and their basic properties, present the most common spectral clustering algorithms, and derive those algorithms from scratch by several different approaches. Advantages and disadvantages of the different spectral clustering algorithms are discussed.

ei

PDF PDF DOI [BibTex]

PDF PDF DOI [BibTex]


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An Automated Combination of Kernels for Predicting Protein Subcellular Localization

Zien, A., Ong, C.

NIPS Workshop on Machine Learning in Computational Biology, December 2007 (talk)

Abstract
Protein subcellular localization is a crucial ingredient to many important inferences about cellular processes, including prediction of protein function and protein interactions.We propose a new class of protein sequence kernels which considers all motifs including motifs with gaps. This class of kernels allows the inclusion of pairwise amino acid distances into their computation. We utilize an extension of the multiclass support vector machine (SVM)method which directly solves protein subcellular localization without resorting to the common approach of splitting the problem into several binary classification problems. To automatically search over families of possible amino acid motifs, we optimize over multiple kernels at the same time. We compare our automated approach to four other predictors on three different datasets, and show that we perform better than the current state of the art. Furthermore, our method provides some insights as to which features are most useful for determining subcellular localization, which are in agreement with biological reasoning.

ei

Web [BibTex]

Web [BibTex]


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A Tutorial on Kernel Methods for Categorization

Jäkel, F., Schölkopf, B., Wichmann, F.

Journal of Mathematical Psychology, 51(6):343-358, December 2007 (article)

Abstract
The abilities to learn and to categorize are fundamental for cognitive systems, be it animals or machines, and therefore have attracted attention from engineers and psychologists alike. Modern machine learning methods and psychological models of categorization are remarkably similar, partly because these two fields share a common history in artificial neural networks and reinforcement learning. However, machine learning is now an independent and mature field that has moved beyond psychologically or neurally inspired algorithms towards providing foundations for a theory of learning that is rooted in statistics and functional analysis. Much of this research is potentially interesting for psychological theories of learning and categorization but also hardly accessible for psychologists. Here, we provide a tutorial introduction to a popular class of machine learning tools, called kernel methods. These methods are closely related to perceptrons, radial-basis-function neural networks and exemplar theories of catego rization. Recent theoretical advances in machine learning are closely tied to the idea that the similarity of patterns can be encapsulated in a positive definite kernel. Such a positive definite kernel can define a reproducing kernel Hilbert space which allows one to use powerful tools from functional analysis for the analysis of learning algorithms. We give basic explanations of some key concepts—the so-called kernel trick, the representer theorem and regularization—which may open up the possibility that insights from machine learning can feed back into psychology.

ei

PDF Web DOI [BibTex]

PDF Web DOI [BibTex]


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Accurate Splice site Prediction Using Support Vector Machines

Sonnenburg, S., Schweikert, G., Philips, P., Behr, J., Rätsch, G.

BMC Bioinformatics, 8(Supplement 10):1-16, December 2007 (article)

Abstract
Background: For splice site recognition, one has to solve two classification problems: discriminating true from decoy splice sites for both acceptor and donor sites. Gene finding systems typically rely on Markov Chains to solve these tasks. Results: In this work we consider Support Vector Machines for splice site recognition. We employ the so-called weighted degree kernel which turns out well suited for this task, as we will illustrate in several experiments where we compare its prediction accuracy with that of recently proposed systems. We apply our method to the genome-wide recognition of splice sites in Caenorhabditis elegans, Drosophila melanogaster, Arabidopsis thaliana, Danio rerio, and Homo sapiens. Our performance estimates indicate that splice sites can be recognized very accurately in these genomes and that our method outperforms many other methods including Markov Chains, GeneSplicer and SpliceMachine. We provide genome-wide predictions of splice sites and a stand-alone prediction tool ready to be used for incorporation in a gene finder. Availability: Data, splits, additional information on the model selection, the whole genome predictions, as well as the stand-alone prediction tool are available for download at http:// www.fml.mpg.de/raetsch/projects/splice.

ei

PDF DOI [BibTex]

PDF DOI [BibTex]


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Challenges in Brain-Computer Interface Development: Induction, Measurement, Decoding, Integration

Hill, NJ.

Invited keynote talk at the launch of BrainGain, the Dutch BCI research consortium, November 2007 (talk)

Abstract
I‘ll present a perspective on Brain-Computer Interface development from T{\"u}bingen. Some of the benefits promised by BCI technology lie in the near foreseeable future, and some further away. Our motivation is to make BCI technology feasible for the people who could benefit from what it has to offer soon: namely, people in the "completely locked-in" state. I‘ll mention some of the challenges of working with this user group, and explain the specific directions they have motivated us to take in developing experimental methods, algorithms, and software.

ei

[BibTex]

[BibTex]


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Some Theoretical Aspects of Human Categorization Behavior: Similarity and Generalization

Jäkel, F.

Biologische Kybernetik, Eberhard-Karls-Universität Tübingen, Tübingen, Germany, November 2007, passed with "ausgezeichnet", summa cum laude, published online (phdthesis)

ei

PDF [BibTex]

PDF [BibTex]


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Statistical Learning Theory Approaches to Clustering

Jegelka, S.

Biologische Kybernetik, Eberhard-Karls-Universität Tübingen, Tübingen, Germany, November 2007 (diplomathesis)

ei

PDF [BibTex]

PDF [BibTex]


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Policy Learning for Robotics

Peters, J.

14th International Conference on Neural Information Processing (ICONIP), November 2007 (talk)

ei

Web [BibTex]

Web [BibTex]


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A unifying framework for robot control with redundant DOFs

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

Autonomous Robots, 24(1):1-12, October 2007 (article)

Abstract
Recently, Udwadia (Proc. R. Soc. Lond. A 2003:1783–1800, 2003) suggested to derive tracking controllers for mechanical systems with redundant degrees-of-freedom (DOFs) using a generalization of Gauss’ principle of least constraint. This method allows reformulating control problems as a special class of optimal controllers. In this paper, we take this line of reasoning one step further and demonstrate that several well-known and also novel nonlinear robot control laws can be derived from this generic methodology. We show experimental verifications on a Sarcos Master Arm robot for some of the derived controllers. The suggested approach offers a promising unification and simplification of nonlinear control law design for robots obeying rigid body dynamics equations, both with or without external constraints, with over-actuation or underactuation, as well as open-chain and closed-chain kinematics.

ei

PDF PDF DOI [BibTex]

PDF PDF DOI [BibTex]