2,964 research outputs found

    SWAN: An expert system with natural language interface for tactical air capability assessment

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    SWAN is an expert system and natural language interface for assessing the war fighting capability of Air Force units in Europe. The expert system is an object oriented knowledge based simulation with an alternate worlds facility for performing what-if excursions. Responses from the system take the form of generated text, tables, or graphs. The natural language interface is an expert system in its own right, with a knowledge base and rules which understand how to access external databases, models, or expert systems. The distinguishing feature of the Air Force expert system is its use of meta-knowledge to generate explanations in the frame and procedure based environment

    Constructive Provability Logic

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    We present constructive provability logic, an intuitionstic modal logic that validates the L\"ob rule of G\"odel and L\"ob's provability logic by permitting logical reflection over provability. Two distinct variants of this logic, CPL and CPL*, are presented in natural deduction and sequent calculus forms which are then shown to be equivalent. In addition, we discuss the use of constructive provability logic to justify stratified negation in logic programming within an intuitionstic and structural proof theory.Comment: Extended version of IMLA 2011 submission of the same titl

    The Twelfth Man? Refereeing Bias in English and German Soccer

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    This paper investigates potential bias in awards of player disciplinary sanctions, in the form of cautions (yellow cards) and dismissals (red cards) by referees in the English Premier League and the Bundesliga. Previous studies of behaviour of soccer referees have not adequately incorporated within-game information. Descriptive statistics from our samples clearly show that home teams receive fewer yellow and red cards than away teams. But biases may be wrongly identified where the modeller has failed to include within-game events such as goals scored and recent cards issued. What appears as referee favouritism may actually be excessive and illegal aggressive behaviour by players in teams that are behind in score. We deal with these issues using a minute-by-minute bivariate probit analysis of yellow and red cards issued in games over six seasons in the two leagues. The significance of a variable to denote score difference at the time of sanction suggests that excessive effort, induced by a losing position, is an important influence on award of yellow and red cards. Controlling for a number of pre-game and within-game variables, we find evidence of home team favouritism in Germany as home teams with running tracks in their stadia attract more yellow and red cards than teams playing in stadia with separation of fans from pitch. This is indicative of referee response to social pressure. Separating the competing teams in matches by favourite and underdog status, as perceived by the betting market, yields further evidence, this time for both leagues, that the source of home teams receiving fewer cards is not just that they are disproportionately often the favoured team. Rather, there appears to be pure referee bias in relative treatments of home and away teams.Soccer, football, referee, sports

    The Pueblo, EC-121, and Mayaguez Incidents: Some Continuities and Changes

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    IEC Fusor Mobile Shielding Unit

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    The VCU Inertial Electrostatic Confinement (IEC) Fusor Senior Design Project provides Virginia Commonwealth University (VCU) with a mobile fusor complete with the necessary shielding to protect operators as well as the general public from potentially hazardous radiation. The VCU IEC fusor is a Farnsworth-Hirsch type reactor, and consists of five basic components; a high voltage power supply, vacuum system, gas regulation system, primary reactor vessel assembly, and radiation shielding. These components were serviced and reassembled on a customized mobile cart. In addition to these components, a specimen holder and viewing monitor were added to the design. The specimen holder provides a practical method for neutron activation experiments, while the viewing monitor allows for safer visualization and operation of the fusor. An engineered cart provides the operator easy transportation of the shielding, fusor, and necessary components. The shielding consists of layers of High Density Polyethylene (HDPE), Borated Polyethylene (BPE), and lead to minimize radiation dose exposure to limits acceptable by the Nuclear Regulatory Commission (NRC). A camera inside the shielding is connected to a display monitor in order to provide a visual depiction of the deuterium ionization and fusion process. This allows operators and audiences to view the internal workings of the fusor from a safe distance. Lastly, an operator’s manual has been drafted to assist future operators with running the fusor. With these additions to the existing design, the fusor assembly serves as a vital asset for researchers, as well as an educational tool for students and teachers.https://scholarscompass.vcu.edu/capstone/1199/thumbnail.jp

    Tine options for alleviating compaction in wheelings

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    Repeated trafficking and harvesting operations lead to high levels of compaction in inter-row wheelings used in asparagus (Asparagus officinalis) production. This reduces soil porosity and infiltration resulting in water ponding on the soil surface. Even on gently sloping land this can result in runoff generation and an increased risk of soil erosion. A winged tine (WT) is currently used by a leading asparagus grower to loosen compacted inter-row wheelings. In order to test the effectiveness of this tine for alleviating compaction and implications for runoff and soil erosion control, it was evaluated alongside several other tine configurations. These were a narrow tine (NT); a narrow tine with two shallow leading tines (NSLT); a winged tine with two shallow leading tines (WSLT); and a modified para-plough (MPP). Testing was conducted under controlled conditions on a sandy loam soil in the Soil Management Facility at Cranfield University, Bedfordshire, UK. Tine performance was assessed at 3 depths (175, 250 and 300 mm) by draught force; soil disturbance (both above and below ground); specific draught for a given level of soil disturbance; surface roughness; and estimated change in soil bulk density. The effectiveness of tines for compaction alleviation and potential for mitigating runoff and soil erosion varied with depth. The most effective tines were found to be the MPP NSLT and the WSLT at 175 mm, 250 mm and 300 mm depth, respectively
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