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Search Results: 1 - 10 of 458 matches for " Hannes Bleuler "
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Extending the Body to Virtual Tools Using a Robotic Surgical Interface: Evidence from the Crossmodal Congruency Task
Ali Sengül, Michiel van Elk, Giulio Rognini, Jane Elizabeth Aspell, Hannes Bleuler, Olaf Blanke
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0049473
Abstract: The effects of real-world tool use on body or space representations are relatively well established in cognitive neuroscience. Several studies have shown, for example, that active tool use results in a facilitated integration of multisensory information in peripersonal space, i.e. the space directly surrounding the body. However, it remains unknown to what extent similar mechanisms apply to the use of virtual-robotic tools, such as those used in the field of surgical robotics, in which a surgeon may use bimanual haptic interfaces to control a surgery robot at a remote location. This paper presents two experiments in which participants used a haptic handle, originally designed for a commercial surgery robot, to control a virtual tool. The integration of multisensory information related to the virtual-robotic tool was assessed by means of the crossmodal congruency task, in which subjects responded to tactile vibrations applied to their fingers while ignoring visual distractors superimposed on the tip of the virtual-robotic tool. Our results show that active virtual-robotic tool use changes the spatial modulation of the crossmodal congruency effects, comparable to changes in the representation of peripersonal space observed during real-world tool use. Moreover, when the virtual-robotic tools were held in a crossed position, the visual distractors interfered strongly with tactile stimuli that was connected with the hand via the tool, reflecting a remapping of peripersonal space. Such remapping was not only observed when the virtual-robotic tools were actively used (Experiment 1), but also when passively held the tools (Experiment 2). The present study extends earlier findings on the extension of peripersonal space from physical and pointing tools to virtual-robotic tools using techniques from haptics and virtual reality. We discuss our data with respect to learning and human factors in the field of surgical robotics and discuss the use of new technologies in the field of cognitive neuroscience.
Collision Avoidance in Next-generation Fiber Positioner Robotic System for Large Survey Spectrograph
Laleh Makarem,Jean-Paul Kneib,Denis Gillet,Hannes Bleuler,Mohamed Bouri,Laurent Jenni,Francisco Prada,Justo Sanchez
Physics , 2013, DOI: 10.1051/0004-6361/201323202
Abstract: Some of the next generation massive spectroscopic survey projects, such as DESI and PFS, plan to use thousands of fiber positioner robots packed at a focal plane to quickly move in parallel the fiber-ends from the previous to the next target points. The most direct trajectories are prone to collision that could damage the robots and impact the survey operation. We thus present here a motion planning method based on a novel decentralized navigation function for collision-free coordination of fiber positioners. The navigation function takes into account the configuration of positioners as well as the actuator constraints. We provide details for the proof of convergence and collision avoidance. Decentralization results in linear complexity for the motion planning as well as dependency of motion duration with respect to the number of positioners. Therefore the coordination method is scalable for large-scale spectrograph robots. The short in-motion duration of positioner robots (~2.5 seconds using typical actuator constraints), will thus allow the time dedicated for observation to be maximized.
La esquizofrenia (1926).
Eugen Bleuler
Revista de la Asociación Espa?ola de Neuropsiquiatría , 1996,
Abstract: Sin resumen.
Collision-free motion planning for fiber positioner robots: discretization of velocity profiles
Laleh Makarem,Jean-Paul Kneib,Denis Gillet,Hannes Bleuler,Mohamed Bouri,Philipp H?rler,Laurent Jenni,Francisco Prada,Justo Sanchez
Physics , 2014, DOI: 10.1117/12.2055185
Abstract: The next generation of large-scale spectroscopic survey experiments such as DESI, will use thousands of fiber positioner robots packed on a focal plate. In order to maximize the observing time with this robotic system we need to move in parallel the fiber-ends of all positioners from the previous to the next target coordinates. Direct trajectories are not feasible due to collision risks that could undeniably damage the robots and impact the survey operation and performance. We have previously developed a motion planning method based on a novel decentralized navigation function for collision-free coordination of fiber positioners. The navigation function takes into account the configuration of positioners as well as their envelope constraints. The motion planning scheme has linear complexity and short motion duration (~2.5 seconds with the maximum speed of 30 rpm for the positioner), which is independent of the number of positioners. These two key advantages of the decentralization designate the method as a promising solution for the collision-free motion-planning problem in the next-generation of fiber-fed spectrographs. In a framework where a centralized computer communicates with the positioner robots, communication overhead can be reduced significantly by using velocity profiles consisting of a few bits only. We present here the discretization of velocity profiles to ensure the feasibility of a real-time coordination for a large number of positioners. The modified motion planning method that generates piecewise linearized position profiles guarantees collision-free trajectories for all the robots. The velocity profiles fit few bits at the expense of higher computational costs.
Developing Micro DC-Brushless Motor Driver and Position Control for Fiber Positioners
Laurent Jenni,Philipp H?rler,Laleh Makarem,Jean-Paul Kneib,Denis Gillet,Hannes Bleuler,Mohamed Bouri,Francisco Prada,Guillermo De Rivera,Justo Sanchez
Physics , 2014, DOI: 10.1117/12.2055197
Abstract: In the large-scale, Dark Energy Spectroscopic Instrument (DESI), thousands of fiber positioners will be used. Those are robotic positioners, with two axis, and having the size of a pen. They are tightly packed on the focal plane of the telescope. Dedicated micro-robots have been developed and they use 4mm brushless DC motors. To simplify the implementation and reduce the space occupancy, each actuator will integrate its own electronic control board. This board will be used to communicate with the central trajectory generator, manage low level control tasks and motor current feeding. In this context, we present a solution for a highly compact electronic. This electronic is composed of two layers. The first is the power stage that can drive simultaneously two brushless motors. The second one consists of a fast microcontroller and deals with different control tasks: communication, acquisition of the hall sensor signals, commutation of the motors phases, and performing position and current regulation. A set of diagnostic functions are also implemented to detect failure in the motors or the sensors, and to sense abnormal load change that may be the result of two robots colliding.
Towards a more realistic sink particle algorithm for the RAMSES code
Andreas Bleuler,Romain Teyssier
Physics , 2014, DOI: 10.1093/mnras/stu2005
Abstract: We present a new sink particle algorithm developed for the Adaptive Mesh Refinement code RAMSES. Our main addition is the use of a clump finder to identify density peaks and their associated regions (the peak patches). This allows us to unambiguously define a discrete set of dense molecular cores as potential sites for sink particle formation. Furthermore, we develop a new scheme to decide if the gas in which a sink could potentially form, is indeed gravitationally bound and rapidly collapsing. This is achieved using a general integral form of the virial theorem, where we use the curvature in the gravitational potential to correctly account for the background potential. We detail all the necessary steps to follow the evolution of sink particles in turbulent molecular cloud simulations, such as sink production, their trajectory integration, sink merging and finally the gas accretion rate onto an existing sink. We compare our new recipe for sink formation to other popular implementations. Statistical properties such as the sink mass function, the average sink mass and the sink multiplicity function are used to evaluate the impact that our new scheme has on accurately predicting fundamental quantities such as the stellar initial mass function or the stellar multiplicity function.
Mit Nachdruck gegen den Verleger. Alte Allianzen und neue Positionen am literarischen Markt
Hannes Fischer
Libreas : Library Ideas , 2012,
Wolfgang Wüst, Die lokale Policey. Normensetzung und Ordnungspolitik auf dem Lande.
Hannes Ludyga
Forum Historiae Iuris , 2008,
Ursula Niedermeier, Lippisches Judenrecht und der Schutz der Juden in den Zivilprozessen der lippischen Obergerichte im 19. Jahrhundert.
Hannes Ludyga
Forum Historiae Iuris , 2008,
Satu Lidman, Zum Spektakel und Abscheu
Hannes Ludyga
Forum Historiae Iuris , 2008,
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