5,794 research outputs found

    Impositive Speech Acts

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    Space-Time Forecasting Using Soft Geostatistics: A Case Study in Forecasting Municipal Water Demand for Phoenix, AZ

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    Managing environmental and social systems in the face of uncertainty requires the best possible forecasts of future conditions. We use space-time variability in historical data and projections of future population density to improve forecasting of residential water demand in the City of Phoenix, Arizona. Our future water estimates are derived using the first and second order statistical moments between a dependent variable, water use, and an independent variable, population density. The independent variable is projected at future points, and remains uncertain. We use adjusted statistical moments that cover projection errors in the independent variable, and propose a methodology to generate information-rich future estimates. These updated estimates are processed in Bayesian Maximum Entropy (BME), which produces maps of estimated water use to the year 2030. Integrating the uncertain estimates into the space-time forecasting process improves forecasting accuracy up to 43.9% over other space-time mapping methods that do not assimilate the uncertain estimates. Further validation studies reveal that BME is more accurate than co-kriging that integrates the error-free independent variable, but shows similar accuracy to kriging with measurement error that processes the uncertain estimates. Our proposed forecasting method benefits from the uncertain estimates of the future, provides up-to-date forecasts of water use, and can be adapted to other socioeconomic and environmental applications.

    Network Latency and Packet Delay Variation in Cyber-physical Systems

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    The problem addressed in this paper is the limitation imposed by network elements, especially Ethernet elements, on the real-time performance of time-critical systems. Most current network elements are concerned only with data integrity, connection, and throughput with no mechanism for enforcing temporal semantics. Existing safety-critical applications and other applications in industry require varying degrees of control over system-wide temporal semantics. In addition, there are emerging commercial applications that require or will benefit from tighter enforcement of temporal semantics in network elements than is currently possible. This paper examines these applications and requirements and suggests possible approaches to imposing temporal semantics on networks. Model-based design and simulation is used to evaluate the effects of network limitations on time-critical systems

    Casting of weldable graphite/magnesium metal matrix composites with built-in metallic inserts

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    Technology innovations directed at the advanced development of a potentially low cost and weldable graphite/magnesium metal matrix composites (MMC) through near net shape pressure casting are described. These MMC components uniquely have built-in metallic inserts to provide an innovative approach for joining or connecting other MMC components through conventional joining techniques such as welding, brazing, mechanical fasteners, etc. Moreover, the metallic inserts trapped within the MMC components can be made to transfer the imposed load efficiently to the continuous graphite fiber reinforcement thus producing stronger, stiffer, and more reliable MMC components. The use of low pressure near net shape casting is economical compared to other MMC fabrication processes. These castable and potentially weldable MMC components can provide great payoffs in terms of high strength, high stiffness, low thermal expansion, lightweight, and easily joinable MMC components for several future NASA space structural, industrial, and commercial applications

    Effects of S100B on Serotonergic Plasticity and Neuroinflammation in the Hippocampus in Down Syndrome and Alzheimer's Disease: Studies in an S100B Overexpressing Mouse Model

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    S100B promotes development and maturation in the mammalian brain. However, prolonged or extensive exposure can lead to neurodegeneration. Two important functions of S100B in this regard, are its role in the development and plasticity of the serotonergic neurotransmitter system, and its role in the cascade of glial changes associated with neuroinflammation. Both of these processes are therefore accelerated towards degeneration in disease processes wherein S100B is increased, notably, Alzheimer's disease (AD) and Down syndrome (DS). In order to study the role of S100B in this context, we have examined S100B overexpressing transgenic mice. Similar to AD and DS, the transgenic animals show a profound change in serotonin innervation. By 28 weeks of age, there is a significant loss of terminals in the hippocampus. Similarly, the transgenic animals show neuroinflammatory changes analogous with AD and DS. These include decreased numbers of mature, stable astroglial cells, increased numbers of activated microglial cells and increased microglial expression of the cell surface receptor RAGE. Eventually, the S100B transgenic animals show neurodegeneration and the appearance of hyperphosphorylated tau structures, as seen in late stage DS and AD. The role of S100B in these conditions is discussed

    It Can Be Done! Planning and Process for Successful Collection Management Projects

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    Many academic libraries face the challenge of decreasing the size of print collections. This paper offers perspectives on a range of activities for successful projects. At Connecticut College, W. Lee Hisle found that, with proper planning and execution, a successful Collection Management Project can be completed without substantial campus turmoil. Hisle discusses project principles, communications strategy used, data used to “sell” the project, and lessons learned. This project allowed the bookstack footprint to be reduced by one-third without loss of access of any item. Pat Tully, from Wesleyan University Library, presents some lessons learned from a last-copy weeding project that was carried out in 2011 to create space for new books and for a substantial art book collection. The project was controversial and led to a series of difficult campus discussions, but inviting faculty input into weeding decisions ultimately strengthened the understanding and trust between the faculty and the library. Pamela Grudzien and Fran Rosen discuss organizational challenges and workflow changes in Technical Services as libraries engage in large collaborative weeding and retention projects. Their libraries are part of the Michigan Shared Print Initiative (MI-SPI), a collaborative project to identify and manage a shared collection of widely held low-use monograph titles. Grudzien, from Central Michigan University, shares new workflows that incorporate retention responsibilities and discusses the development of a tool that facilitates member communication about volumes that are missing or in poor condition. Rosen shares details about a comprehensive project using MI-SPI weeding lists at Ferris State University
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