Header logo is


2019


Thumb xl cover walking seq
AirCap – Aerial Outdoor Motion Capture

Ahmad, A., Price, E., Tallamraju, R., Saini, N., Lawless, G., Ludwig, R., Martinovic, I., Bülthoff, H. H., Black, M. J.

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2019), Workshop on Aerial Swarms, November 2019 (misc)

Abstract
This paper presents an overview of the Grassroots project Aerial Outdoor Motion Capture (AirCap) running at the Max Planck Institute for Intelligent Systems. AirCap's goal is to achieve markerless, unconstrained, human motion capture (mocap) in unknown and unstructured outdoor environments. To that end, we have developed an autonomous flying motion capture system using a team of aerial vehicles (MAVs) with only on-board, monocular RGB cameras. We have conducted several real robot experiments involving up to 3 aerial vehicles autonomously tracking and following a person in several challenging scenarios using our approach of active cooperative perception developed in AirCap. Using the images captured by these robots during the experiments, we have demonstrated a successful offline body pose and shape estimation with sufficiently high accuracy. Overall, we have demonstrated the first fully autonomous flying motion capture system involving multiple robots for outdoor scenarios.

ps

[BibTex]

2019


[BibTex]


Thumb xl mosh heroes icon
Method for providing a three dimensional body model

Loper, M., Mahmood, N., Black, M.

September 2019, U.S.~Patent 10,417,818 (misc)

Abstract
A method for providing a three-dimensional body model which may be applied for an animation, based on a moving body, wherein the method comprises providing a parametric three-dimensional body model, which allows shape and pose variations; applying a standard set of body markers; optimizing the set of body markers by generating an additional set of body markers and applying the same for providing 3D coordinate marker signals for capturing shape and pose of the body and dynamics of soft tissue; and automatically providing an animation by processing the 3D coordinate marker signals in order to provide a personalized three-dimensional body model, based on estimated shape and an estimated pose of the body by means of predicted marker locations.

ps

MoSh Project pdf [BibTex]


no image
High-Fidelity Multiphysics Finite Element Modeling of Finger-Surface Interactions with Tactile Feedback

Serhat, G., Kuchenbecker, K. J.

Work-in-progress paper (2 pages) presented at the IEEE World Haptics Conference (WHC), Tokyo, Japan, July 2019 (misc)

Abstract
In this study, we develop a high-fidelity finite element (FE) analysis framework that enables multiphysics simulation of the human finger in contact with a surface that is providing tactile feedback. We aim to elucidate a variety of physical interactions that can occur at finger-surface interfaces, including contact, friction, vibration, and electrovibration. We also develop novel FE-based methods that will allow prediction of nonconventional features such as real finger-surface contact area and finger stickiness. We envision using the developed computational tools for efficient design and optimization of haptic devices by replacing expensive and lengthy experimental procedures with high-fidelity simulation.

hi

[BibTex]

[BibTex]


no image
Fingertip Friction Enhances Perception of Normal Force Changes

Gueorguiev, D., Lambert, J., Thonnard, J., Kuchenbecker, K. J.

Work-in-progress paper (2 pages) presented at the IEEE World Haptics Conference (WHC), Tokyo, Japan, July 2019 (misc)

Abstract
Using a force-controlled robotic platform, we tested the human perception of positive and negative modulations in normal force during passive dynamic touch, which also induced a strong related change in the finger-surface lateral force. In a two-alternative forced-choice task, eleven participants had to detect brief variations in the normal force compared to a constant controlled pre-stimulation force of 1 N and report whether it had increased or decreased. The average 75% just noticeable difference (JND) was found to be around 0.25 N for detecting the peak change and 0.30 N for correctly reporting the increase or the decrease. Interestingly, the friction coefficient of a subject’s fingertip positively correlated with his or her performance at detecting the change and reporting its direction, which suggests that humans may use the lateral force as a sensory cue to perceive variations in the normal force.

hi

[BibTex]

[BibTex]


Thumb xl pocketrendering
Inflatable Haptic Sensor for the Torso of a Hugging Robot

Block, A. E., Kuchenbecker, K. J.

Work-in-progress paper (2 pages) presented at the IEEE World Haptics Conference (WHC), Tokyo, Japan, July 2019 (misc)

Abstract
During hugs, humans naturally provide and intuit subtle non-verbal cues that signify the strength and duration of an exchanged hug. Personal preferences for this close interaction may vary greatly between people; robots do not currently have the abilities to perceive or understand these preferences. This work-in-progress paper discusses designing, building, and testing a novel inflatable torso that can simultaneously soften a robot and act as a tactile sensor to enable more natural and responsive hugging. Using PVC vinyl, a microphone, and a barometric pressure sensor, we created a small test chamber to demonstrate a proof of concept for the full torso. While contacting the chamber in several ways common in hugs (pat, squeeze, scratch, and rub), we recorded data from the two sensors. The preliminary results suggest that the complementary haptic sensing channels allow us to detect coarse and fine contacts typically experienced during hugs, regardless of user hand placement.

hi

Project Page [BibTex]

Project Page [BibTex]


Thumb xl figure1
Understanding the Pull-off Force of the Human Fingerpad

Nam, S., Kuchenbecker, K. J.

Work-in-progress paper (2 pages) presented at the IEEE World Haptics Conference (WHC), Tokyo, Japan, July 2019 (misc)

Abstract
To understand the adhesive force that occurs when a finger pulls off of a smooth surface, we built an apparatus to measure the fingerpad’s moisture, normal force, and real contact area over time during interactions with a glass plate. We recorded a total of 450 trials (45 interactions by each of ten human subjects), capturing a wide range of values across the aforementioned variables. The experimental results showed that the pull-off force increases with larger finger contact area and faster detachment rate. Additionally, moisture generally increases the contact area of the finger, but too much moisture can restrict the increase in the pull-off force.

hi

[BibTex]

[BibTex]


Thumb xl h a image3
The Haptician and the Alphamonsters

Forte, M. P., L’Orsa, R., Mohan, M., Nam, S., Kuchenbecker, K. J.

Student Innovation Challenge on Implementing Haptics in Virtual Reality Environment presented at the IEEE World Haptics Conference, Tokyo, Japan, July 2019, Maria Paola Forte, Rachael L'Orsa, Mayumi Mohan, and Saekwang Nam contributed equally to this publication (misc)

Abstract
Dysgraphia is a neurological disorder characterized by writing disabilities that affects between 7% and 15% of children. It presents itself in the form of unfinished letters, letter distortion, inconsistent letter size, letter collision, etc. Traditional therapeutic exercises require continuous assistance from teachers or occupational therapists. Autonomous partial or full haptic guidance can produce positive results, but children often become bored with the repetitive nature of such activities. Conversely, virtual rehabilitation with video games represents a new frontier for occupational therapy due to its highly motivational nature. Virtual reality (VR) adds an element of novelty and entertainment to therapy, thus motivating players to perform exercises more regularly. We propose leveraging the HTC VIVE Pro and the EXOS Wrist DK2 to create an immersive spellcasting “exergame” (exercise game) that helps motivate children with dysgraphia to improve writing fluency.

hi

Student Innovation Challenge – Virtual Reality [BibTex]

Student Innovation Challenge – Virtual Reality [BibTex]


Thumb xl s ban outdoors 1   small
Explorations of Shape-Changing Haptic Interfaces for Blind and Sighted Pedestrian Navigation

Spiers, A., Kuchenbecker, K. J.

pages: 6, Workshop paper (6 pages) presented at the CHI 2019 Workshop on Hacking Blind Navigation, May 2019 (misc) Accepted

Abstract
Since the 1960s, technologists have worked to develop systems that facilitate independent navigation by vision-impaired (VI) pedestrians. These devices vary in terms of conveyed information and feedback modality. Unfortunately, many such prototypes never progress beyond laboratory testing. Conversely, smartphone-based navigation systems for sighted pedestrians have grown in robustness and capabilities, to the point of now being ubiquitous. How can we leverage the success of sighted navigation technology, which is driven by a larger global market, as a way to progress VI navigation systems? We believe one possibility is to make common devices that benefit both VI and sighted individuals, by providing information in a way that does not distract either user from their tasks or environment. To this end we have developed physical interfaces that eschew visual, audio or vibratory feedback, instead relying on the natural human ability to perceive the shape of a handheld object.

hi

[BibTex]

[BibTex]


no image
Bimanual Wrist-Squeezing Haptic Feedback Changes Speed-Force Tradeoff in Robotic Surgery Training

Cao, E., Machaca, S., Bernard, T., Wolfinger, B., Patterson, Z., Chi, A., Adrales, G. L., Kuchenbecker, K. J., Brown, J. D.

Extended abstract presented as an ePoster at the Annual Meeting of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), Baltimore, USA, April 2019 (misc) Accepted

hi

[BibTex]

[BibTex]


no image
Interactive Augmented Reality for Robot-Assisted Surgery

Forte, M. P., Kuchenbecker, K. J.

Extended abstract presented as an Emerging Technology ePoster at the Annual Meeting of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), Baltimore, Maryland, USA, April 2019 (misc)

hi

Project Page [BibTex]

Project Page [BibTex]


no image
A Design Tool for Therapeutic Social-Physical Human-Robot Interactions

Mohan, M., Kuchenbecker, K. J.

Workshop paper (3 pages) presented at the HRI Pioneers Workshop, Daegu, South Korea, March 2019 (misc) Accepted

Abstract
We live in an aging society; social-physical human-robot interaction has the potential to keep our elderly adults healthy by motivating them to exercise. After summarizing prior work, this paper proposes a tool that can be used to design exercise and therapy interactions to be performed by an upper-body humanoid robot. The interaction design tool comprises a teleoperation system that transmits the operator’s arm motions, head motions and facial expression along with an interface to monitor and assess the motion of the user interacting with the robot. We plan to use this platform to create dynamic and intuitive exercise interactions.

hi

Project Page [BibTex]

Project Page [BibTex]


Thumb xl webteaser
Perceiving Systems (2016-2018)
Scientific Advisory Board Report, 2019 (misc)

ps

pdf [BibTex]

pdf [BibTex]


no image
More Powerful Selective Kernel Tests for Feature Selection

Lim, J. N., Yamada, M., Jitkrittum, W., Terada, Y., Matsui, S., Shimodaira, H.

2019 (misc) Submitted

ei

arXiv [BibTex]

arXiv [BibTex]


Thumb xl teaser
Toward Expert-Sourcing of a Haptic Device Repository

Seifi, H., Ip, J., Agrawal, A., Kuchenbecker, K. J., MacLean, K. E.

Glasgow, UK, 2019 (misc)

Abstract
Haptipedia is an online taxonomy, database, and visualization that aims to accelerate ideation of new haptic devices and interactions in human-computer interaction, virtual reality, haptics, and robotics. The current version of Haptipedia (105 devices) was created through iterative design, data entry, and evaluation by our team of experts. Next, we aim to greatly increase the number of devices and keep Haptipedia updated by soliciting data entry and verification from haptics experts worldwide.

hi

link (url) [BibTex]

link (url) [BibTex]


no image
A special issue on hydrogen-based Energy storage

Hirscher, M.

{International Journal of Hydrogen Energy}, 44, pages: 7737, Elsevier, Amsterdam, 2019 (misc)

mms

DOI [BibTex]

DOI [BibTex]


no image
Analytical classical density functionals from an equation learning network

Lin, S., Martius, G., Oettel, M.

2019, arXiv preprint \url{https://arxiv.org/abs/1910.12752} (misc)

al

[BibTex]

[BibTex]


no image
Nanoscale X-ray imaging of spin dynamics in Yttrium iron garnet

Förster, J., Wintz, S., Bailey, J., Finizio, S., Josten, E., Meertens, D., Dubs, C., Bozhko, D. A., Stoll, H., Dieterle, G., Traeger, N., Raabe, J., Slavin, A. N., Weigand, M., Gräfe, J., Schütz, G.

2019 (misc)

mms

link (url) [BibTex]

link (url) [BibTex]


no image
Reconfigurable nanoscale spin wave majority gate with frequency-division multiplexing

Talmelli, G., Devolder, T., Träger, N., Förster, J., Wintz, S., Weigand, M., Stoll, H., Heyns, M., Schütz, G., Radu, I., Gräfe, J., Ciubotaru, F., Adelmann, C.

2019 (misc)

Abstract
Spin waves are excitations in ferromagnetic media that have been proposed as information carriers in spintronic devices with potentially much lower operation power than conventional charge-based electronics. The wave nature of spin waves can be exploited to design majority gates by coding information in their phase and using interference for computation. However, a scalable spin wave majority gate design that can be co-integrated alongside conventional Si-based electronics is still lacking. Here, we demonstrate a reconfigurable nanoscale inline spin wave majority gate with ultrasmall footprint, frequency-division multiplexing, and fan-out. Time-resolved imaging of the magnetisation dynamics by scanning transmission x-ray microscopy reveals the operation mode of the device and validates the full logic majority truth table. All-electrical spin wave spectroscopy further demonstrates spin wave majority gates with sub-micron dimensions, sub-micron spin wave wavelengths, and reconfigurable input and output ports. We also show that interference-based computation allows for frequency-division multiplexing as well as the computation of different logic functions in the same device. Such devices can thus form the foundation of a future spin-wave-based superscalar vector computing platform.

mms

link (url) [BibTex]

link (url) [BibTex]


Thumb xl blockdiag
Event-triggered Learning

Solowjow, F., Trimpe, S.

2019 (techreport) Submitted

ics

arXiv PDF [BibTex]


no image
Visual-Inertial Mapping with Non-Linear Factor Recovery

Usenko, V., Demmel, N., Schubert, D., Stückler, J., Cremers, D.

2019, arXiv:1904.06504 (misc)

ev

[BibTex]

[BibTex]


no image
Hydrogen Energy

Hirscher, M., Autrey, T., Orimo, S.

{ChemPhysChem}, 20, pages: 1153-1411, Wiley-VCH, Weinheim, Germany, 2019 (misc)

mms

link (url) DOI [BibTex]

link (url) DOI [BibTex]

2011


no image
PAC-Bayesian Analysis of Martingales and Multiarmed Bandits

Seldin, Y., Laviolette, F., Shawe-Taylor, J., Peters, J., Auer, P.

Max Planck Institute for Biological Cybernetics, Tübingen, Germany, May 2011 (techreport)

Abstract
We present two alternative ways to apply PAC-Bayesian analysis to sequences of dependent random variables. The first is based on a new lemma that enables to bound expectations of convex functions of certain dependent random variables by expectations of the same functions of independent Bernoulli random variables. This lemma provides an alternative tool to Hoeffding-Azuma inequality to bound concentration of martingale values. Our second approach is based on integration of Hoeffding-Azuma inequality with PAC-Bayesian analysis. We also introduce a way to apply PAC-Bayesian analysis in situation of limited feedback. We combine the new tools to derive PAC-Bayesian generalization and regret bounds for the multiarmed bandit problem. Although our regret bound is not yet as tight as state-of-the-art regret bounds based on other well-established techniques, our results significantly expand the range of potential applications of PAC-Bayesian analysis and introduce a new analysis tool to reinforcement learning and many other fields, where martingales and limited feedback are encountered.

ei

PDF Web [BibTex]

2011


PDF Web [BibTex]


no image
Non-stationary Correction of Optical Aberrations

Schuler, C., Hirsch, M., Harmeling, S., Schölkopf, B.

(1), Max Planck Institute for Intelligent Systems, Tübingen, Germany, May 2011 (techreport)

Abstract
Taking a sharp photo at several megapixel resolution traditionally relies on high grade lenses. In this paper, we present an approach to alleviate image degradations caused by imperfect optics. We rely on a calibration step to encode the optical aberrations in a space-variant point spread function and obtain a corrected image by non-stationary deconvolution. By including the Bayer array in our image formation model, we can perform demosaicing as part of the deconvolution.

ei

PDF [BibTex]

PDF [BibTex]


no image
Multiple Kernel Learning: A Unifying Probabilistic Viewpoint

Nickisch, H., Seeger, M.

Max Planck Institute for Biological Cybernetics, March 2011 (techreport)

Abstract
We present a probabilistic viewpoint to multiple kernel learning unifying well-known regularised risk approaches and recent advances in approximate Bayesian inference relaxations. The framework proposes a general objective function suitable for regression, robust regression and classification that is lower bound of the marginal likelihood and contains many regularised risk approaches as special cases. Furthermore, we derive an efficient and provably convergent optimisation algorithm.

ei

Web [BibTex]

Web [BibTex]


no image
Multiple testing, uncertainty and realistic pictures

Langovoy, M., Wittich, O.

(2011-004), EURANDOM, Technische Universiteit Eindhoven, January 2011 (techreport)

Abstract
We study statistical detection of grayscale objects in noisy images. The object of interest is of unknown shape and has an unknown intensity, that can be varying over the object and can be negative. No boundary shape constraints are imposed on the object, only a weak bulk condition for the object's interior is required. We propose an algorithm that can be used to detect grayscale objects of unknown shapes in the presence of nonparametric noise of unknown level. Our algorithm is based on a nonparametric multiple testing procedure. We establish the limit of applicability of our method via an explicit, closed-form, non-asymptotic and nonparametric consistency bound. This bound is valid for a wide class of nonparametric noise distributions. We achieve this by proving an uncertainty principle for percolation on nite lattices.

ei

PDF [BibTex]

PDF [BibTex]


no image
Nonconvex proximal splitting: batch and incremental algorithms

Sra, S.

(2), Max Planck Institute for Intelligent Systems, Tübingen, Germany, 2011 (techreport)

Abstract
Within the unmanageably large class of nonconvex optimization, we consider the rich subclass of nonsmooth problems having composite objectives (this includes the extensively studied convex, composite objective problems as a special case). For this subclass, we introduce a powerful, new framework that permits asymptotically non-vanishing perturbations. In particular, we develop perturbation-based batch and incremental (online like) nonconvex proximal splitting algorithms. To our knowledge, this is the rst time that such perturbation-based nonconvex splitting algorithms are being proposed and analyzed. While the main contribution of the paper is the theoretical framework, we complement our results by presenting some empirical results on matrix factorization.

ei

PDF [BibTex]

PDF [BibTex]


no image
Preparation of high-efficiency nanostructures of crystalline silicon at low temperatures, as catalyzed by metals: The decisive role of interface thermodynamics

Wang, Zumin, Jeurgens, Lars P. H., Mittemeijer, Eric J.

2011 (mpi_year_book)

Abstract
Metals may help to convert semiconductors from a disordered (amorphous) to an ordered (crystalline) form at low temperatures. A general, quantitative model description has been developed on the basis of interface thermodynamics, which provides fundamental understanding of such so-called metal-induced crystallization (MIC) of amorphous semiconductors. This fundamental understanding can allow the low-temperature (< 200 ºC) manufacturing of high-efficiency solar cells and crystalline-Si-based nanostructures on cheap and flexible substrates such as glasses, plastics and possibly even papers.

link (url) [BibTex]


no image
The sweet coat of living cells – from supramolecular organization and dynamics to biological function

Richter, Ralf

2011 (mpi_year_book)

Abstract
Many biological cells endow themselves with a sugar-rich coat that plays a key role in the protection of the cell and in structuring and communicating with its environment. An outstanding property of these pericellular coats is their dynamic self-organization into strongly hydrated and gel-like meshworks. Tailor-made model systems that are constructed from the molecular building blocks of pericellular coats can help to understand how the coats function.

link (url) [BibTex]

2006


no image
Minimal Logical Constraint Covering Sets

Sinz, F., Schölkopf, B.

(155), Max Planck Institute for Biological Cybernetics, Tübingen, December 2006 (techreport)

Abstract
We propose a general framework for computing minimal set covers under class of certain logical constraints. The underlying idea is to transform the problem into a mathematical programm under linear constraints. In this sense it can be seen as a natural extension of the vector quantization algorithm proposed by Tipping and Schoelkopf. We show which class of logical constraints can be cast and relaxed into linear constraints and give an algorithm for the transformation.

ei

PDF [BibTex]

2006


PDF [BibTex]


no image
New Methods for the P300 Visual Speller

Biessmann, F.

(1), (Editors: Hill, J. ), Max-Planck Institute for Biological Cybernetics, Tübingen, Germany, November 2006 (techreport)

ei

PDF [BibTex]

PDF [BibTex]


no image
Geometric Analysis of Hilbert Schmidt Independence criterion based ICA contrast function

Shen, H., Jegelka, S., Gretton, A.

(PA006080), National ICT Australia, Canberra, Australia, October 2006 (techreport)

ei

Web [BibTex]

Web [BibTex]


no image
A tutorial on spectral clustering

von Luxburg, U.

(149), Max Planck Institute for Biological Cybernetics, Tübingen, August 2006 (techreport)

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. Nevertheless, on the first glance spectral clustering looks a bit mysterious, and it is not obvious to see why it works at all and what it really does. This article is a tutorial introduction to spectral clustering. 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 [BibTex]

PDF [BibTex]


no image
Towards the Inference of Graphs on Ordered Vertexes

Zien, A., Raetsch, G., Ong, C.

(150), Max Planck Institute for Biological Cybernetics, Tübingen, August 2006 (techreport)

Abstract
We propose novel methods for machine learning of structured output spaces. Specifically, we consider outputs which are graphs with vertices that have a natural order. We consider the usual adjacency matrix representation of graphs, as well as two other representations for such a graph: (a) decomposing the graph into a set of paths, (b) converting the graph into a single sequence of nodes with labeled edges. For each of the three representations, we propose an encoding and decoding scheme. We also propose an evaluation measure for comparing two graphs.

ei

PDF [BibTex]

PDF [BibTex]


no image
An Automated Combination of Sequence Motif Kernels for Predicting Protein Subcellular Localization

Zien, A., Ong, C.

(146), Max Planck Institute for Biological Cybernetics, Tübingen, April 2006 (techreport)

Abstract
Protein subcellular localization is a crucial ingredient to many important inferences about cellular processes, including prediction of protein function and protein interactions. While many predictive computational tools have been proposed, they tend to have complicated architectures and require many design decisions from the developer. We propose an elegant and fully automated approach to building a prediction system for protein subcellular localization. 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 further propose a multiclass support vector machine 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 generalize our method to optimize over multiple kernels at the same time. We compare our automated approach to four other predictors on three different datasets.

ei

PDF Web [BibTex]

PDF Web [BibTex]


no image
Training a Support Vector Machine in the Primal

Chapelle, O.

(147), Max Planck Institute for Biological Cybernetics, Tübingen, April 2006, The version in the "Large Scale Kernel Machines" book is more up to date. (techreport)

Abstract
Most literature on Support Vector Machines (SVMs) concentrate on the dual optimization problem. In this paper, we would like to point out that the primal problem can also be solved efficiently, both for linear and non-linear SVMs, and there is no reason for ignoring it. Moreover, from the primal point of view, new families of algorithms for large scale SVM training can be investigated.

ei

PDF [BibTex]

PDF [BibTex]


no image
Cross-Validation Optimization for Structured Hessian Kernel Methods

Seeger, M., Chapelle, O.

Max-Planck Institute for Biological Cybernetics, Tübingen, Germany, February 2006 (techreport)

Abstract
We address the problem of learning hyperparameters in kernel methods for which the Hessian of the objective is structured. We propose an approximation to the cross-validation log likelihood whose gradient can be computed analytically, solving the hyperparameter learning problem efficiently through nonlinear optimization. Crucially, our learning method is based entirely on matrix-vector multiplication primitives with the kernel matrices and their derivatives, allowing straightforward specialization to new kernels or to large datasets. When applied to the problem of multi-way classification, our method scales linearly in the number of classes and gives rise to state-of-the-art results on a remote imaging task.

ei

PDF Web [BibTex]

PDF Web [BibTex]


no image
Statistical Learning of LQG controllers

Theodorou, E.

Technical Report-2006-1, Computational Action and Vision Lab University of Minnesota, 2006, clmc (techreport)

am

PDF [BibTex]

PDF [BibTex]