203,918 research outputs found

    Self-organizing robot formations using velocity potential fields commands for material transfer

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    Mobile robot formations differ in accordance with the mission, environment, and robot abilities. In the case of decentralized control, the ability to achieve the shapes of these formations needs to be built in the controllers of each autonomous robot. In this paper, self-organizing formations control for material transfer is investigated, as an alternative to automatic guided vehicles. Leader–follower approach is applied for controllers design to drive the robots toward the goal. The results confirm the ability of velocity potential approach for motion control of both self-organizing formations

    Humanoid Motion Description Language

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    In this paper we propose a description language for specifying motions for humanoid robots and for allowing humanoid robots to acquire motor skills. Locomotion greatly increases our ability to interact with our environments, which in turn increases our mental abilities. This principle also applies to humanoid robots. However, there are great difficulties to specify humanoid motions and to represent motor skills, which in most cases require four-dimensional space representations. We propose a representation framework that includes the following attributes: motion description layers, egocentric reference system, progressive quantized refinement, and automatic constraint satisfaction. We also outline strategies for acquiring new motor skills by learning from trial and error, macro approach, and programming. Then, we outline the development of a new humanoid motion description language called Cybele

    Jakob Leupold’s Imaginary Automatic Anamorphic Devices of 1713

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    In 1713 the scientific instrument-maker Jakob Leupold published designs for three machines were the first attempt to design machinery with internal moving parts that replaced human agency in creating original images. This paper first analyzes his text and engravings in order to explain how he proposed to do this, given contemporary materials and command of physical forces. Next, it characterizes the devices as a transition from concepts of incision to concepts of mirroring, taken as models of the history of mechanical reproduction. And finally, Leupold’s replacement of the sighting grid with differential gears points to a set of problems appearing in contemporary philosophy represented in Rococo artistic production of this period as well. Taking the proposed devices in context, they help to theorize the complex notions of creative activity in Rococo visual culture. Taken as an episode in the history of communications, they instance the development of conceptions of personhood and of physical forces at stake in the invention of automated media

    Priming of Pop-Out Does not Affect the Shooting Line Illusion

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    We combined a shooting-line illusion with a visual search pop-out task in an effort to determine whether priming of pop-out was due to acceleratcd processing of visual information in the primed dimension. While the priming effect and the line-motion percept were replicated, the visual search task showed no influence on the perceived direction of line motion. These results indicate that the priming effect does not accelerate early visual processing.National Institutes of Health-National Eye Institute (EY05087, 49620-93-1-0407

    Automatic correction of hand pointing in stereoscopic depth

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    In order to examine whether stereoscopic depth information could drive fast automatic correction of hand pointing, an experiment was designed in a 3D visual environment in which participants were asked to point to a target at different stereoscopic depths as quickly and accurately as possible within a limited time window (≤300 ms). The experiment consisted of two tasks: "depthGO" in which participants were asked to point to the new target position if the target jumped, and "depthSTOP" in which participants were instructed to abort their ongoing movements after the target jumped. The depth jump was designed to occur in 20% of the trials in both tasks. Results showed that fast automatic correction of hand movements could be driven by stereoscopic depth to occur in as early as 190 ms.This work was supported by the Grants from the National Natural Science Foundation of China (60970062 and 61173116) and the Doctoral Fund of Ministry of Education of China (20110072110014)

    Ultrasonic biomedical measuring and recording apparatus

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    A train of ultrasonic pulses is beamed into the body of an animal. Organs intercepted by the beam reflect echo pulses following each transmitted pulse. An electronic gate with a variable width and a variable time delay relative to the transmitted pulse is utilized for selecting echoes derived from other organs or portions of organs. The integral of the echo signals received within the first half of the gate period is subtracted from a corresponding integral of the echo signal received during the second half of the gate to derive an error signal for controlling the time delay of the gate. In this manner, the selected echo signal is always maintained in the center of the gate
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