12,890 research outputs found

    TRICCS: A proposed teleoperator/robot integrated command and control system for space applications

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    Robotic systems will play an increasingly important role in space operations. An integrated command and control system based on the requirements of space-related applications and incorporating features necessary for the evolution of advanced goal-directed robotic systems is described. These features include: interaction with a world model or domain knowledge base, sensor feedback, multiple-arm capability and concurrent operations. The system makes maximum use of manual interaction at all levels for debug, monitoring, and operational reliability. It is shown that the robotic command and control system may most advantageously be implemented as packages and tasks in Ada

    Attitude control and damping system for spacecraft Patent

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    Utilization of momentum devices for forming attitude control and damping system for spacecraf

    Complex hyperbolic free groups with many parabolic elements

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    We consider in this work representations of the of the fundamental group of the 3-punctured sphere in PU(2,1){\rm PU}(2,1) such that the boundary loops are mapped to PU(2,1){\rm PU}(2,1). We provide a system of coordinates on the corresponding representation variety, and analyse more specifically those representations corresponding to subgroups of (3,3,)(3,3,\infty)-groups. In particular we prove that it is possible to construct representations of the free group of rank two \la a,b\ra in PU(2,1){\rm PU}(2,1) for which aa, bb, abab, ab1ab^{-1}, ab2ab^2, a2ba^2b and [a,b][a,b] all are mapped to parabolics.Comment: 21 pages, 11 figure

    Exploring the bulk of tidal charged micro-black holes

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    We study the bulk corresponding to tidal charged brane-world black holes. We employ a propagating algorithm which makes use of the three-dimensional multipole expansion and analytically yields the metric elements as functions of the five-dimensional coordinates and of the ADM mass, tidal charge and brane tension. Since the projected brane equations cannot determine how the charge depends on the mass, our main purpose is to select the combinations of these parameters for which black holes of microscopic size possess a regular bulk. Our results could in particular be relevant for a better understanding of TeV-scale black holes.Comment: Latex, 15 pages, 1 table, 5 figures; Section 3.2 extended, typos corrected, no change in conclusion

    The Newtonian limit at intermediate energies

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    We study the metric solutions for the gravitational equations in Modified Gravity Models (MGMs). In models with negative powers of the scalar curvature, we show that the Newtonian Limit (NL) is well defined as a limit at intermediate energies, in contrast with the usual low energy interpretation. Indeed, we show that the gravitational interaction is modified at low densities or low curvatures.Comment: 4 pages, REVTeX 4; minor typos corrected, one reference adde

    A flexible telerobotic system for space operations

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    The objective and design of a proposed goal-oriented knowledge-based telerobotic system for space operations is described. This design effort encompasses the elements of the system executive and user interface and the distribution and general structure of the knowledge base, the displays, and the task sequencing. The objective of the design effort is to provide an expandable structure for a telerobotic system that provides cooperative interaction between the human operator and computer control. The initial phase of the implementation provides a rule-based, goal-oriented script generator to interface to the existing control modes of a telerobotic research system, in the Intelligent Systems Research Lab at NASA Research Center

    Economic Impacts of Planned Transportation Investments in New Jersey

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    This report demonstrates that New Jersey's plans to invest in transportation infrastructure over the next decade will result in nearly 27,000 full-time jobs per year. It also shows that the state's transportation investments will generate economic impacts in the form of employment, income, gross domestic product, and state and local tax revenues. The report is the result of a joint study conducted by the Heldrich Center and the Center for Urban Policy Research at Rutgers University's Edward J. Bloustein School of Planning and Public Policy

    Electrostatics in the Stability and Misfolding of the Prion Protein: Salt Bridges, Self-Energy, and Solvation

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    Using a recently developed mesoscopic theory of protein dielectrics, we have calculated the salt bridge energies, total residue electrostatic potential energies, and transfer energies into a low dielectric amyloid-like phase for 12 species and mutants of the prion protein. Salt bridges and self energies play key roles in stabilizing secondary and tertiary structural elements of the prion protein. The total electrostatic potential energy of each residue was found to be invariably stabilizing. Residues frequently found to be mutated in familial prion disease were among those with the largest electrostatic energies. The large barrier to charged group desolvation imposes regional constraints on involvement of the prion protein in an amyloid aggregate, resulting in an electrostatic amyloid recruitment profile that favours regions of sequence between alpha helix 1 and beta strand 2, the middles of helices 2 and 3, and the region N-terminal to alpha helix 1. We found that the stabilization due to salt bridges is minimal among the proteins studied for disease-susceptible human mutants of prion protein

    Description and simulation of an integrated power and attitude control system concept for space-vehicle application

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    An Integrated Power and Attitude Control System (IPACS) concept with potential application to a broad class of space missions is discussed. A description is given of the basic concept of combining the onboard energy storage and attitude control functions by storing energy in spinning flywheels which are used to provide control torques. A shuttle-launched Research and Applications Module (RAM) A303B solar-observatory mission having stringent pointing requirements (1.0 arc second) is selected to investigate possible interactions between energy storage and attitude control. A simulation of this spacecraft involving actual laboratory-model control-system hardware is presented. Simulation results are discussed which indicate that the IPACS concept, even in a failure-mode configuration, can readily meet the RAM A303B pointing requirements

    Risk management and the stratification of logistics service provision

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    This paper stems from a research project undertaken between 2007 and 2010. It discusses the development of supply chain management together with the understanding of the impact of supply chain risk. It gives an overview of the increasing stratification of service provision from first part logistics to joint service consortia and proposes a model balancing risk with service provision
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