6,337 research outputs found

    Multiple cooperating manipulators: The case of kinematically redundant arms

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    Existing work concerning two or more manipulators simultaneously grasping and transferring a common load is continued and extended. Specifically considered is the case of one or more arms being kinematically redundant. Some existing results in the modeling and control of single redundant arms and multiple manipulators are reviewed. The cooperating situation is modeled in terms of a set of coordinates representing object motion and internal object squeezing. Nominal trajectories in these coordinates are produced via actuator load distribution algorithms introduced previously. A controller is developed to track these desired object trajectories while making use of the kinematic redundancy to additionally aid the cooperation and coordination of the system. It is shown how the existence of kinematic redundancy within the system may be used to enhance the degree of cooperation achievable

    Industrial Engineering and the Law

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    BOOM BACKLASH made recent headlines in the May 26th issue of The Wall Street Journal. The sub-heading, Efficiency Falls and Pay Training Costs Increase as Labor Supply Shrinks delves into the heart of industrial engineering. This represents, also, an expansive and enigmatic economic problem which is now confronting employers in northern Ohio and western Pennsylvania. It is the job of the industrial engineer to deal with the resulting problems of decreased productivity, contract erosion, and unbalanced labor relations

    Seasonal Variation in Diet of a Marginal Population of the Hispid Cotton Rat, Sigmodon hispidus

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    Cotton rats live in oldfields, habitats with a variety of mostly herbaceous plants. Based on other studies, the hispid cotton rat, Sigmodon hispidus, eats many kinds of herbaceous plants but grasses predominate. In contrast, our population of cotton rats ate many monocots but mostly they were not grasses. Our study sought to determine the diet of the cotton rat in eastern Virginia, near the northern limit of distribution on the Atlantic Coast. Fecal samples, collected each month during an on-going capture-mark-release demographic study of the rodent community, were analyzed using a standard method. A greater variety of foods (including insects) was eaten in the summer and autumn than in winter and spring. In winter, when much herbaceous vegetation is standing dead, cotton rats supplemented their diets with pine bark. Cotton rats ate significantly greater proportions of monocots in winter and spring, an apparent response to the need for more calories to compensate for greater heat loss. In summer and autumn, cotton rats enhanced their diets with significantly greater proportions of the more nutritious but harder to digest dicots. Reproductive females ate significantly more dicots and less monocots than males and non-reproductive females, whose diets were similar

    Hierarchically nanostructured films and applications thereof

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    In one aspect, nanostructured films are described herein comprising controlled architectures on multiple length scales (e.g. .gtoreq.3). As described further herein, the ability to control film properties on multiple length scales enables tailoring structures of the films to specific applications including, but not limited to, optoelectronic, catalytic and photoelectrochemical cell applications. In some embodiments, a nanostructured film comprises a porous inorganic scaffold comprising particles of an electrically insulating inorganic oxide. An electrically conductive metal oxide coating is adhered to the porous inorganic scaffold, wherein the conductive metal oxide coating binds adjacent particles of the insulating inorganic oxide

    Diets of Baird’s Beaked Whales, \u3ci\u3eBerardius bairdii\u3c/i\u3e, in the Southern Sea Of Okhotsk and Off the Pacific Coast Of Honshu, Japan

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    Stomach contents were analyzed from 127 Baird’s beaked whales, Berardizls bairdii, taken in coastal waters of Japan. During late July-August of 1985- 1987, 1989, and 1991, 107 samples were collected from off the Pacific coast of Honshu. An additional 20 samples were collected from whales taken in the southern Sea of Okhotsk during late August-September of 1988 and 1989. Prey identification using fish otoliths and cephalopod beaks revealed the whales fed primarily on deep-water gadiform fishes and cephalopods in both regions. Prey species diversity and the percentage of cephalopods and fish differed between the two regions. Off the Pacific coast of Honshu the whales fed primarily on benthopelagic fishes (81.8%) and only 18.0% on cephalopods. Eight species of fish representing two families, the codlings (Moridae) and the grenadiers (Macrouridde), collectively made up 81.3% of the total. Thirty species of cephalopods representing 14 families made up 12.7%. In the southern Sea of Okhotsk, cephalopods accounted for 87.1% of stomach contents. The families Gonatidae and Cranchiidae were the predominant cephalopod prey, accounting for 86.7% of the diet. Gadiform fish accounted for only 12.9% of the diet. Longfin codling, Laernonma longipes, was the dominant fish prey in both regions. Depth distribution of the two commonly consumed fish off the Pacific coast of Honshu indicate the whales in this region fed primarily at depths ranging from 800 to 1,200 m

    Two-dimensional quantum Yang-Mills theory with corners

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    The solution of quantum Yang-Mills theory on arbitrary compact two-manifolds is well known. We bring this solution into a TQFT-like form and extend it to include corners. Our formulation is based on an axiomatic system that we hope is flexible enough to capture actual quantum field theories also in higher dimensions. We motivate this axiomatic system from a formal Schroedinger-Feynman quantization procedure. We also discuss the physical meaning of unitarity, the concept of vacuum, (partial) Wilson loops and non-orientable surfaces.Comment: 31 pages, 6 figures, LaTeX + AMS; minor corrections, reference update
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