44,410 research outputs found

    Anytime Point-Based Approximations for Large POMDPs

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    The Partially Observable Markov Decision Process has long been recognized as a rich framework for real-world planning and control problems, especially in robotics. However exact solutions in this framework are typically computationally intractable for all but the smallest problems. A well-known technique for speeding up POMDP solving involves performing value backups at specific belief points, rather than over the entire belief simplex. The efficiency of this approach, however, depends greatly on the selection of points. This paper presents a set of novel techniques for selecting informative belief points which work well in practice. The point selection procedure is combined with point-based value backups to form an effective anytime POMDP algorithm called Point-Based Value Iteration (PBVI). The first aim of this paper is to introduce this algorithm and present a theoretical analysis justifying the choice of belief selection technique. The second aim of this paper is to provide a thorough empirical comparison between PBVI and other state-of-the-art POMDP methods, in particular the Perseus algorithm, in an effort to highlight their similarities and differences. Evaluation is performed using both standard POMDP domains and realistic robotic tasks

    An Entrepreneurial Theory of Formal Organizations. Part I - Patterns of Formal Organizations

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    Theory of formal organizations with ordering of relevant dat

    An automatically-shifted two-speed transaxle system for an electric vehicle

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    An automatic shifting scheme for a two speed transaxle for use with an electric vehicle propulsion system is described. The transaxle system was to be installed in an instrumented laboratory propulsion system of an ac electric vehicle drive train. The transaxle which had been fabricated is also described

    Dynamical control of quantum state transfer within hybrid open systems

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    We analyze quantum state-transfer optimization within hybrid open systems, from a "noisy" (write-in) qubit to its "quiet" counterpart (storage qubit). Intriguing interplay is revealed between our ability to avoid bath-induced errors that profoundly depend on the bath-memory time and the limitations imposed by leakage out of the operational subspace. Counterintuitively, under no circumstances is the fastest transfer optimal (for a given transfer energy)

    Welding monitoring system

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    This invention relates to systems for remotely monitoring automatic welding operations, and more particularly to a system wherein the welder is readily positionable, while components of the optical system remain fixed. A welder having an electrode is mounted in an enclosure containing a pair of mirrors. The electrode passes through an opening in the first mirror and a gas cup. The mirror reflects an image of a welding operation taken through the opening of the gas cup to the second mirror. The second mirror then reflects the image through a rotary coupling to a third mirror which, in turn, reflects the image to a receiving lense mounted to a second rotatable coupling. The image is then projected via a fiber optic bundle to a filter unit where selected wavelengths of light are filtered from the welding image. The filter unit is coupled to an enlarger which enlarges the image and passes it to a camera. The camera is connected to an electronic eclipser which selectively darkens the brightest portions of the image. Finally, the image is recorded by a video tape recorder and displayed by a monitor

    An Aerial Gamma Ray Survey of Hunterston Nuclear Power Station in 14-15 April and 4 May 1994

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    Phonographic neighbors, not orthographic neighbors, determine word naming latencies

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    The orthographic neighborhood size (N) of a word—the number of words that can be formed from that word by replacing one letter with another in its place—has been found to have facilitatory effects in word naming. The orthographic neighborhood hypothesis attributes this facilitation to interactive effects. A phonographic neighborhood hypothesis, in contrast, attributes the effect to lexical print-sound conversion. According to the phonographic neighborhood hypothesis, phonographic neighbors (words differing in one letter and one phoneme, e.g., stove and stone) should facilitate naming, and other orthographic neighbors (e.g., stove and shove) should not. The predictions of these two hypotheses are tested. Unique facilitatory phonographic N effects were found in four sets of word naming mega-study data, along with an absence of facilitatory orthographic N effects. These results implicate print-sound conversion—based on consistent phonology—in neighborhood effects rather than word-letter feedback

    Risk Factors for Non-communicable Diseases Among Adults of 25-65 Years at Kakamega County General Hospital, Kenya

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    In Kenya the growing number of premature deaths with half of all hospital admissions and 33% of all deaths are associated with Non-communicable diseases. The study determined the physical measurements and lipid parameters of adults 25-65 years at Kakamega County General Hospital. Data was collected using the WHO STEPs Instrument: Physical measurements assessed were Mid Upper Arm Circumference, Waist Hip measurements, Body mass Index and blood pressure. The study significance level was 0.05. Data was analyzed using SPSS version 20. Descriptive statistics was used. χ2 test of independence was used to find out the relationship between anthropometric measurements and lipid parameters. Data was presented in form of tables, figures and texts. There was a significant relationship between BMI and Triglycerideχ2 (12, N=60)= 25.752 P=0.012, BMI and LDLχ2(8,N=60)=19.312 p=0.013, BMI and Total Cholesterol χ2(8, N=60)=18.694 p=0.017, MUAC and HDL χ2(4, N=60) =14.446 p=0.006, WHR and Total Cholesterol χ2(2, N=60)=17.985 p=0.000, WHR and LDL χ2(2, N=60)=15.246p=0.000. The study advocated for policies to reduce the incidences of risk factors for NCDs which will assist in achievement of Sustainable Development Goals. Kenyan population are in need of screening for risks associated with NCDs
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