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2012


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A sensorimotor paradigm for Bayesian model selection

Genewein, T, Braun, DA

Frontiers in Human Neuroscience, 6(291):1-16, October 2012 (article)

Abstract
Sensorimotor control is thought to rely on predictive internal models in order to cope efficiently with uncertain environments. Recently, it has been shown that humans not only learn different internal models for different tasks, but that they also extract common structure between tasks. This raises the question of how the motor system selects between different structures or models, when each model can be associated with a range of different task-specific parameters. Here we design a sensorimotor task that requires subjects to compensate visuomotor shifts in a three-dimensional virtual reality setup, where one of the dimensions can be mapped to a model variable and the other dimension to the parameter variable. By introducing probe trials that are neutral in the parameter dimension, we can directly test for model selection. We found that model selection procedures based on Bayesian statistics provided a better explanation for subjects’ choice behavior than simple non-probabilistic heuristics. Our experimental design lends itself to the general study of model selection in a sensorimotor context as it allows to separately query model and parameter variables from subjects.

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DOI [BibTex]

2012


DOI [BibTex]


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Three-dimensional microfiber devices that mimic physiological environments to probe cell mechanics and signaling

Ruder, W. C., Pratt, E. D., Bakhru, S., Sitti, M., Zappe, S., Cheng, C., Antaki, J. F., LeDuc, P. R.

Lab on a Chip, 12(10):1775-1779, Royal Society of Chemistry, 2012 (article)

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[BibTex]

[BibTex]


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Active visual search in unknown environments using uncertain semantics

Aydemir, Alper, Pronobis, Andrzej, Jensfelt, Patric, Sj, Kristoffer, Aydemir, Alper, Jensfelt, Patric, Aydemir, A, Jensfelt, P, Aydemir, A, Jensfelt, P, others

Transactions, 1, pages: 2329-2335, IEEE, 2012 (article)

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[BibTex]

[BibTex]


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Modelling of conductive atomic force microscope probes for scanning tunnelling microscope operation

Ozcan, O, Sitti, M

IET Micro \& Nano Letters, 7(4):329-333, IET, 2012 (article)

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[BibTex]

[BibTex]


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Shape memory polymer-based flexure stiffness control in a miniature flapping-wing robot

Hines, L., Arabagi, V., Sitti, M.

IEEE Transactions on Robotics, 28(4):987-990, IEEE, 2012 (article)

pi

[BibTex]

[BibTex]


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Micro-manipulation using rotational fluid flows induced by remote magnetic micro-manipulators

Ye, Z., Diller, E., Sitti, M.

Journal of Applied Physics, 112(6):064912, AIP, 2012 (article)

pi

Project Page [BibTex]

Project Page [BibTex]


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Risk-Sensitivity in Bayesian Sensorimotor Integration

Grau-Moya, J, Ortega, PA, Braun, DA

PLoS Computational Biology, 8(9):1-7, sep 2012 (article)

Abstract
Information processing in the nervous system during sensorimotor tasks with inherent uncertainty has been shown to be consistent with Bayesian integration. Bayes optimal decision-makers are, however, risk-neutral in the sense that they weigh all possibilities based on prior expectation and sensory evidence when they choose the action with highest expected value. In contrast, risk-sensitive decision-makers are sensitive to model uncertainty and bias their decision-making processes when they do inference over unobserved variables. In particular, they allow deviations from their probabilistic model in cases where this model makes imprecise predictions. Here we test for risk-sensitivity in a sensorimotor integration task where subjects exhibit Bayesian information integration when they infer the position of a target from noisy sensory feedback. When introducing a cost associated with subjects' response, we found that subjects exhibited a characteristic bias towards low cost responses when their uncertainty was high. This result is in accordance with risk-sensitive decision-making processes that allow for deviations from Bayes optimal decision-making in the face of uncertainty. Our results suggest that both Bayesian integration and risk-sensitivity are important factors to understand sensorimotor integration in a quantitative fashion.

ei

DOI [BibTex]

DOI [BibTex]


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The principles of XMCD and its application to L-edges in transition metals

Schütz, G.

In Linear and Chiral Dichroism in the Electron Miroscope, pages: 23-42, Pan Stanford Publishing Pte.Ltd., Singapore, 2012 (incollection)

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[BibTex]

[BibTex]


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Accurate dosimetry in scanning transmission X-ray microscopes via the cross-linking threshold dose of poly(methyl methacrylate)

Leontowich, A. F. G., Hitchcock, A. P., Tyliszczak, T., Weigand, M., Wang, J., Karunakaran, C.

{Journal of Synchrotron Radiation}, 19(6):976-987, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Biogenic potassium salt particles as seeds for secondary organic aerosal in the amazon

Pöhlker, C., Wiedemann, K. T., Sinha, B., Shiraiwa, M., Gunthe, S. S., Smith, M., Su, H., Artaxo, P., Chen, Q., Cheng, Y., Elbert, W., Gilles, M. K., Kilcoyne, A. L. D., Moffet, R. C., Weigand, M., Martin, S. T., Pöschl, U., Andreae, M. O.

{Science}, 337, pages: 1075-1078, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Metal@COFs: Covalent organic frameworks as templates for Pd nanoparticles and hydrogen storage properties of Pd@COF-102 hybrid material

Kalidindi, S. B., Oh, H., Hirscher, M., Esken, D., Wiktor, C., Turner, S., Van Tendeloo, G., Fischer, R. A.

{Chemistry-a European Journal}, 18(35):10848-10856, VCH Verlagsgesellschaft, Weinheim, Germany, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Ion beam lithography for direct patterning of high accuracy large area X-ray elements in gold on membranes

Nadzeyka, A., Peto, L., Bauerdick, S., Mayer, M., Keskinbora, K., Grévent, C., Weigand, M., Hirscher, M., Schütz, G.

{Microelectronic Engineering}, 98, pages: 198-201, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Remotely addressable magnetic composite micropumps

Diller, E., Miyashita, S., Sitti, M.

Rsc Advances, 2(9):3850-3856, Royal Society of Chemistry, 2012 (article)

pi

[BibTex]

[BibTex]


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An Introduction to Random Forests for Multi-class Object Detection

Gall, J., Razavi, N., van Gool, L.

In Outdoor and Large-Scale Real-World Scene Analysis, 7474, pages: 243-263, LNCS, (Editors: Dellaert, Frank and Frahm, Jan-Michael and Pollefeys, Marc and Rosenhahn, Bodo and Leal-Taix’e, Laura), Springer, 2012 (incollection)

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code code for Hough forest publisher's site pdf Project Page [BibTex]

code code for Hough forest publisher's site pdf Project Page [BibTex]


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Home 3D body scans from noisy image and range data

Weiss, A., Hirshberg, D., Black, M. J.

In Consumer Depth Cameras for Computer Vision: Research Topics and Applications, pages: 99-118, 6, (Editors: Andrea Fossati and Juergen Gall and Helmut Grabner and Xiaofeng Ren and Kurt Konolige), Springer-Verlag, 2012 (incollection)

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Project Page [BibTex]

Project Page [BibTex]


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Micro- and nanoscale fluid flow on chemical channels

Dörfler, Fabian, Rauscher, Markus, Koplik, Joel, Harting, Jens, Dietrich, S.

{Soft Matter}, 8(35):9221-9234, 2012 (article)

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Novel characterization of the adsorption sites in large pore Metal-Organic Frameworks: Combination of X-ray powder diffraction and thermal desorption spectroscopy

Soleimani Dorcheh, A., Dinnebier, R. E., Kuc, A., Magdysyuk, O., Adams, F., Denysenko, D., Heine, T., Volkmer, D., Donner, W., Hirscher, M.

{Physical Chemistry Chemical Physics}, 14(37):12892-12897, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Tunnel contacts for spin injection into silicon: The Si-Co interface with and without a MgO tunnel barrier - A study by high-resolution Rutherford backscattering

Dash, S. P., Goll, D., Kopold, P., Carstanjen, H. D.

{Advances in Materials Science and Engineering}, 2012, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Fast spin-wave-mediated magnetic vortex core reversal

Kammerer, M., Stoll, H., Noske, M., Sproll, M., Weigand, M., Illg, C., Woltersdorf, G., Fähnle, M., Back, C., Schütz, G.

{Physical Review B}, 86(13), 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Deformation-driven formation of equilibrium phases in the Cu-Ni alloys

Straumal, B. B., Protasova, S. G., Mazilkin, A. A., Rabkin, E., Goll, D., Schütz, G., Baretzky, B., Valiev, R. Z.

{Journal of Materials Science}, 47, pages: 360-367, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Nanosponges for hydrogen storage

Schlichtenmayer, M., Hirscher, M.

{Journal of Materials Chemistry}, 22, pages: 10134-10143, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Magnetic and electronic properties of the interface between half metallic Fe3O4 and semiconducting ZnO

Brück, S., Paul, M., Tian, H., Müller, A., Kufer, D., Praetorius, C., Fauth, K., Audehm, P., Goering, E., Verbeeck, J., Van Tendeloo, G., Sing, M., Claessen, R.

{Applied Physics Letters}, 100, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Amorphous interlayers between crystalline grains in ferromagnetic ZnO films

Straumal, B. B., Protasova, S. G., Mazilkin, A. A., Baretzky, B., Myatiev, A. A., Straumal, P. B., Tietze, T., Schütz, G., Goering, E.

{Materials Letters}, 71, pages: 21-24, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Model-free reinforcement learning of impedance control in stochastic environments

Stulp, Freek, Buchli, Jonas, Ellmer, Alice, Mistry, Michael, Theodorou, Evangelos A., Schaal, S.

Autonomous Mental Development, IEEE Transactions on, 4(4):330-341, 2012 (article)

am

[BibTex]

[BibTex]


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Shape-Programmable Soft Capsule Robots for Semi-Implantable Drug Delivery

Yim, S., Sitti, M.

Mechatronics, IEEE/ASME Transactions on, 2012 (article)

pi

Project Page [BibTex]

Project Page [BibTex]


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Control of multiple heterogeneous magnetic microrobots in two dimensions on nonspecialized surfaces

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

IEEE Transactions on Robotics, 28(1):172-182, IEEE, 2012 (article)

pi

[BibTex]

[BibTex]


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Gecko-Inspired Controllable Adhesive Structures Applied to Micromanipulation

Mengüç, Y., Yang, S. Y., Kim, S., Rogers, J. A., Sitti, M.

Advanced Functional Materials, 22(6):1245-1245, WILEY-VCH Verlag, 2012 (article)

pi

Project Page [BibTex]

Project Page [BibTex]


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Elastomer surfaces with directionally dependent adhesion strength and their use in transfer printing with continuous roll-to-roll applications

Yang, S. Y., Carlson, A., Cheng, H., Yu, Q., Ahmed, N., Wu, J., Kim, S., Sitti, M., Ferreira, P. M., Huang, Y., others,

Advanced Materials, 24(16):2117-2122, WILEY-VCH Verlag, 2012 (article)

pi

[BibTex]

[BibTex]


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Effect of retraction speed on adhesion of elastomer fibrillar structures

Abusomwan, U., Sitti, M.

Applied Physics Letters, 101(21):211907, AIP, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Accelerated diffusion and phase transformations in Co-Cu alloys driven by the severe plastic deformation

Straumal, B. B., Mazilkin, A. A., Baretzky, B., Schütz, G., Rabkin, E., Valiev, R. Z.

{Special Issue on Advanced Materials Science in Bulk Nanostructured Metals}, 53(1):63-71, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Unusual flux jumps above 12 K in non-homogeneous MgB2 thin films

Treiber, S., Stahl, C., Schütz, G., Albrecht, J.

{Superconductor Science \& Technology}, 25, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Ferromagnetism of nanostructured zinc oxide films

Straumal, B. B., Mazilkin, A. A., Protasova, S. G., Straumal, P. B., Myatiev, A. A., Schütz, G., Goering, E., Baretzky, B.

{The Physics of Metals and Metallography}, 113(13):1244-1256, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Frequencies and polarization vectors of phonons: Results from force constants which are fitted to experimental data or calculated ab initio

Illg, C., Meyer, B., Fähnle, M.

{Physical Review B}, 86(17), Published by the American Physical Society through the American Institute of Physics, Woodbury, NY, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Grain boundary wetting by a second solid phase in the Zr-Nb alloys

Straumal, B. B., Gornakova, A. S., Kucheev, Y. O., Baretzky, B., Nekrasov, A. N.

{Journal of Materials Engineering and Performance}, 21(5):721-724, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Grain boundary wetting in the NdFeB-based hard magnetic alloys

Straumal, B. B., Kucheev, Y. O., Yatskovskaya, I. L., Mogilnikova, I. V., Schütz, G., Nekrasov, A. N., Baretzky, B.

{Journal of Materials Science}, 47(24):8352-8359, 2012 (article)

mms

DOI [BibTex]

DOI [BibTex]


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Reinforcement Learning with Sequences of Motion Primitives for Robust Manipulation

Stulp, F., Theodorou, E., Schaal, S.

IEEE Transactions on Robotics, 2012 (article)

am

[BibTex]

[BibTex]


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Impact and Surface Tension in Water: a Study of Landing Bodies

Shih, B., Laham, L., Lee, K. J., Krasnoff, N., Diller, E., Sitti, M.

Bio-inspired Robotics Final Project, Carnegie Mellon University, 2012 (article)

pi

[BibTex]

[BibTex]


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Design and rolling locomotion of a magnetically actuated soft capsule endoscope

Yim, S., Sitti, M.

IEEE Transactions on Robotics, 28(1):183-194, IEEE, 2012 (article)

pi

Project Page [BibTex]

Project Page [BibTex]


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Design and manufacturing of a controllable miniature flapping wing robotic platform

Arabagi, V., Hines, L., Sitti, M.

The International Journal of Robotics Research, 31(6):785-800, SAGE Publications Sage UK: London, England, 2012 (article)

pi

[BibTex]

[BibTex]


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Chemotactic steering of bacteria propelled microbeads

Kim, D., Liu, A., Diller, E., Sitti, M.

Biomedical microdevices, 14(6):1009-1017, Springer US, 2012 (article)

pi

Project Page [BibTex]

Project Page [BibTex]


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Magnetic proximity effect in YBa2Cu3O7 / La2/3Ca1/3MnO3 and YBa2Cu3O7 / LaMnO3+δsuperlattices

Satapathy, D. K., Uribe-Laverde, M. A., Marozau, I., Malik, V. K., Das, S., Wagner, T., Marcelot, C., Stahn, J., Brück, S., Rühm, A., Macke, S., Tietze, T., Goering, E., Frañó, A., Kim, J., Wu, M., Benckiser, E., Keimer, B., Devishvili, A., Toperverg, B. P., Merz, M., Nagel, P., Schuppler, S., Bernhard, C.

{Physical Review Letters}, 108, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Structural and chemical characterization on the nanoscale

Stierle, A., Carstanjen, H.-D., Hofmann, S.

In Nanoelectronics and Information Technology. Advanced Electronic Materials and Novel Devices, pages: 233-254, Wiley-VCH, Weinheim, 2012 (incollection)

mms

[BibTex]

[BibTex]


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Noble gases and microporous frameworks; from interaction to application

Soleimani Dorcheh, A., Denysenko, D., Volkmer, D., Donner, W., Hirscher, M.

{Microporous and Mesoporous Materials}, 162, pages: 64-68, Elsevier, Amsterdam, 2012 (article)

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DOI [BibTex]

DOI [BibTex]


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Note: Unique characterization possibilities in the ultra high vacuum scanning transmission x-ray microscope (UHV-STXM) "MAXYMUS" using a rotatable permanent magnetic field up to 0.22 T

Nolle, D., Weigand, M., Audehm, P., Goering, E., Wiesemann, U., Wolter, C., Nolle, E., Schütz, G.

{Review of Scientific Instruments}, 83(4), 2012 (article)

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DOI [BibTex]


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Rutherford Backscattering

Carstanjen, H. D.

In Nanoelectronics and Information Technology. Advanced Electronic Materials and Novel Devices, pages: 250-252, WILEY-VCH Verlag, Weinheim, Germany, 2012 (incollection)

mms

[BibTex]

[BibTex]


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Microstructure and superconducting properties of MgB2 films prepared by solid state reaction of multilayer precursors of the elements

Kugler, B., Stahl, C., Treiber, S., Soltan, S., Haug, S., Schütz, G., Albrecht, J.

{Thin Solid Films}, 520, pages: 6985-6988, 2012 (article)

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DOI [BibTex]

DOI [BibTex]

2007


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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]

2007


PDF PDF DOI [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]