25,661 research outputs found

    Optimizations of Human Restraint Systems for Short-Period Acceleration

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    A restraint system's main function is to restrain its occupant when his vehicle is subjected to acceleration. If the restraint system is rigid and well-fitting (to eliminate slack) then it will transmit the vehicle acceleration to its occupant without modifying it in any way. Few present-day restraint systems are stiff enough to give this one-to-one transmission characteristic, and depending upon their dynamic characteristics and the nature of the vehicle's acceleration-time history, they will either magnify or attenuate the acceleration. Obviously an optimum restraint system will give maximum attenuation of an input acceleration. In the general case of an arbitrary acceleration input, a computer must be used to determine the optimum dynamic characteristics for the restraint system. Analytical solutions can be obtained for certain simple cases, however, and these cases are considered in this paper, after the concept of dynamic models of the human body is introduced. The paper concludes with a description of an analog computer specially developed for the Air Force to handle completely general mechanical restraint optimization programs of this type, where the acceleration input may be any arbitrary function of time

    Sonora exploratory study for the detection of wheat-leaf rust

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    The applicability of LANDSAT remote sensing technology to the detection of a wheat-leaf-rust epidemic in Sonora, Mexico, during 1977 was investigated. LANDSAT data acquired during crop years 1975-76 and 1976-77 were clustered, classified, and analyzed in order to detect agricultural changes. Analysis of 1977 data indicates a significant proportion of the identified wheat is stressed (potentially rust-infected). Additional analyses show a significant increase in fallowing during the year, as well as a substantial decrease in reservoir levels in the Sonora agricultural region. Ground observations are required to substantiate these analyses. The possibility exists that heat-rust is not LANDSAT detectable and that the clusters identified as containing stressed signatures represent different varieties of wheat or perhaps nonwheat crops

    The integrated analysis procedure for identification of spring small grains and barley

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    There are no author-identified significant results in this report

    Is a Semantic Web Agent a Knowledge-Savvy Agent?

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    The issue of knowledge sharing has permeated the field of distributed AI and in particular, its successor, multiagent systems. Through the years, many research and engineering efforts have tackled the problem of encoding and sharing knowledge without the need for a single, centralized knowledge base. However, the emergence of modern computing paradigms such as distributed, open systems have highlighted the importance of sharing distributed and heterogeneous knowledge at a larger scale—possibly at the scale of the Internet. The very characteristics that define the Semantic Web—that is, dynamic, distributed, incomplete, and uncertain knowledge—suggest the need for autonomy in distributed software systems. Semantic Web research promises more than mere management of ontologies and data through the definition of machine-understandable languages. The openness and decentralization introduced by multiagent systems and service-oriented architectures give rise to new knowledge management models, for which we can’t make a priori assumptions about the type of interaction an agent or a service may be engaged in, and likewise about the message protocols and vocabulary used. We therefore discuss the problem of knowledge management for open multi-agent systems, and highlight a number of challenges relating to the exchange and evolution of knowledge in open environments, which pertinent to both the Semantic Web and Multi Agent System communities alike

    Sensitivity Analysis of Flexible Provisioning

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    This technical report contains a sensitivity analysis to extend our previous work. We show that our flexible service provisioning strategy is robust to inaccurate performance information (when the available information is within 10% of the true value), and that it degrades gracefully as the information becomes less accurate. We also identify and discuss one particular case where inaccurate information may lead to undesirable losses in highly unreliable environments

    On the general position subset selection problem

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    Let f(n,ℓ)f(n,\ell) be the maximum integer such that every set of nn points in the plane with at most ℓ\ell collinear contains a subset of f(n,ℓ)f(n,\ell) points with no three collinear. First we prove that if ℓ≀O(n)\ell \leq O(\sqrt{n}) then f(n,ℓ)≄Ω(nln⁡ℓ)f(n,\ell)\geq \Omega(\sqrt{\frac{n}{\ln \ell}}). Second we prove that if ℓ≀O(n(1−ϔ)/2)\ell \leq O(n^{(1-\epsilon)/2}) then f(n,ℓ)≄Ω(nlog⁡ℓn)f(n,\ell) \geq \Omega(\sqrt{n\log_\ell n}), which implies all previously known lower bounds on f(n,ℓ)f(n,\ell) and improves them when ℓ\ell is not fixed. A more general problem is to consider subsets with at most kk collinear points in a point set with at most ℓ\ell collinear. We also prove analogous results in this setting

    An Effective Strategy for the Flexible Provisioning of Service Workflows

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    Recent advances in service-oriented frameworks and semantic Web technologies have enabled software agents to discover and invoke resources over large distributed systems, in order to meet their high-level objectives. However, most work has failed to acknowledge that such systems are complex and dynamic multi-agent systems, where service providers act autonomously and follow their own decision-making procedures. Hence, the behaviour of these providers is inherently uncertain - services may fail or take uncertain amounts of time to complete. In this work, we address this uncertainty and take an agent-oriented approach to the problem of provisioning service providers for the constituent tasks of abstract workflows. Specifically, we describe an algorithm that uses redundancy to deal with unreliable providers, and we demonstrate that it achieves an 8-14% improvement in average utility over previous work, while performing up to 6 times as well as approaches that do not consider service uncertainty. We also show that our algorithm performs well in the presence of inaccurate service performance information

    Advancements and progressions in greyhound racing: a professional and personal trajectory

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    The context of these works is in relation to my work within the world of regulated greyhound racing within the United Kingdom, and represents a progression from my earliest interests in biomechanics and statistical analysis, through the development of this knowledge and the acquisition of new skills as the research progressed. It details my roles within disease control, research into exercise-associated sudden death, and the links with other research threads that stemmed from the first projects involved with the physics of wet sand tracks. I hope to show that my love of science, not just an acceptance but an enquiring methodology, has resulted in my progression through a variety of issues and as a result made a major contribution to the greyhound world. The links I make stem from my need to keep ideas separate, yet at the same time use the links so that I can jump from one line of investigation to another. The expansion of knowledge resulting from wet sand track investigations has enabled a much better understanding of the natural and applied processes involved in maintaining wet sand tracks, and also paved the way for a critical analysis of the interaction of greyhounds’ feet with the running surface
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