Flexible Resolution of Authorisation Conflicts in Distributed Systems

Flexible Resolution of Authorisation Conflicts in Distributed System

A THREE-DIMENSIONAL ANALYSIS OF THE WINDMILL STYLE OF SOFTBALL DELIVERY FOR FAST AND CHANGE-UP PITCHING

INTRODUCTION The purpose of this study was to investigate the windmill style of softball delivery for fast and change-up pitches by three groups of female players (middle school, high school, and collegiate). This investigation examined kinematic and kinetic characteristics of the upper extremity, factors that contributed to differences between the magnitude of ball velocity, and the force exerted against the ground during the pitching motion. METHODS The volunteers for this study were 18 right-handed highly skilled female pitchers. Each subject performed three trials of each style of pitch. The best performance by subject by style was selected for analysis. The subjects' pitches were recorded by two video cameras which operated with a 60 Hz field rate. This data was then reduced to 3D coordinates using the DLT method. RESULTS It was concluded that the mean time for the fast pitch, from stride foot takeoff from the force platform to the point of ball release, was less than for the change-up pitch. The major factors that contributed to ball velocity were flexion of the elbow, shoulder, and hip joints. A stride length above 90 percent of the subject's height did not contribute to increased ball velocity. The normalized maximum mean value of the vertical ground reaction force for both styles of pitching, among the three groups, differed little. The difference in ball velocity between the fast and change-up pitches for middle school subjects were small compared to differences noted in the other two groups. The resultant joint torque at the shoulder and elbow were greater in high school and college subjects than in middle school subjects. Also, high school and college subjects showed greater peak angular velocity of the pitching arm than middle school subjects. CONCLUSIONS The following conclusions were based on the results of this study. Within subject stride length should not vary substantially in delivering fast and change-up pitches. A stride length of 80 to 90 percent of subject height is recommended. Vertical ground reaction force may not contribute substantially to ball velocity. Rapid acceleration and deceleration of the pitching arm that were noted in the delivery has implications for strengthening both the elbow and shoulder flexors and extensors

EVALUATION OF ATHLETIC PERFORMANCE THROUGH GAME ANALYSIS OF TENNIS

The purpose of this study was to explore the use of three-dimensional (3D) analysis techniques for match analysis in tennis. It was determined that temporal and kinematic parameters obtained from 3D video analysis of the 32 finalists in the 1997 Korean Cup provided insight into successful performance. These parameters induded success of first service, distance of receiving player from the ball, height of stroke impact, and player movement pattern

Model-Based Edge Detector for Spectral Imagery Using Sparse Spatiospectral Masks

Two model-based algorithms for edge detection in spectral imagery are developed that specifically target capturing intrinsic features such as isoluminant edges that are characterized by a jump in color but not in intensity. Given prior knowledge of the classes of reflectance or emittance spectra associated with candidate objects in a scene, a small set of spectral-band ratios, which most profoundly identify the edge between each pair of materials, are selected to define a edge signature. The bands that form the edge signature are fed into a spatial mask, producing a sparse joint spatiospectral nonlinear operator. The first algorithm achieves edge detection for every material pair by matching the response of the operator at every pixel with the edge signature for the pair of materials. The second algorithm is a classifier-enhanced extension of the first algorithm that adaptively accentuates distinctive features before applying the spatiospectral operator. Both algorithms are extensively verified using spectral imagery from the airborne hyperspectral imager and from a dots-in-a-well midinfrared imager. In both cases, the multicolor gradient (MCG) and the hyperspectral/spatial detection of edges (HySPADE) edge detectors are used as a benchmark for comparison. The results demonstrate that the proposed algorithms outperform the MCG and HySPADE edge detectors in accuracy, especially when isoluminant edges are present. By requiring only a few bands as input to the spatiospectral operator, the algorithms enable significant levels of data compression in band selection. In the presented examples, the required operations per pixel are reduced by a factor of 71 with respect to those required by the MCG edge detector

Scaling laws for the photo-ionisation cross section of two-electron atoms

The cross sections for single-electron photo-ionisation in two-electron atoms show fluctuations which decrease in amplitude when approaching the double-ionisation threshold. Based on semiclassical closed orbit theory, we show that the algebraic decay of the fluctuations can be characterised in terms of a threshold law $\sigma \propto |E|^{\mu}$ as $E \to 0_-$ with exponent $\mu$ obtained as a combination of stability exponents of the triple-collision singularity. It differs from Wannier's exponent dominating double ionisation processes. The details of the fluctuations are linked to a set of infinitely unstable classical orbits starting and ending in the non-regularisable triple collision. The findings are compared with quantum calculations for a model system, namely collinear helium.Comment: 4 pages, 1 figur

In-Situ Growth of Nucleus Geometry to Dual Types of Periodically Ringed Assemblies in Poly(nonamethylene terephthalate)

Monitoring of nucleus geometry and growth into dual types of periodically ring-banded morphology in poly(nonamethylene terephthalate) (PNT), respectively, Type-1 and Type-2, are done with detailed analyses using polarized-light optical microscopy (POM) in-situ CCD recording; the periodic assembly morphologies are characterized using atomic-force microscopy (AFM) and scanning electron microscopy (SEM). Different annealing treatments (Tmax = 110, 120, 130 °C) are accomplished at a crystallization temperature of 85 °C; effects on the nucleus geometry, number (25–10%) and volume fractions (33–15%) of Type-2 among two types of banded PNT spherulites are expounded. Growth of a specific type of periodically banded PNT spherulite is initiated from either highly elongated sheaf-like or well-rounded nuclei, with the final grown lamellae being self-packed as multi-shell structures. Nucleation geometry and crystallization parameters collectively lead to development of multiple types of banded PNT spherulites of different relative fractions

U.S. and foreign competition in the developing countries of the Asian Pacific Rim

노트 : Volume Title: The United States in the world economy Chapter Tilte: U.S. and foreign competition in the developing countries of the Asian Pacific Ri

Generating a Schr\"odinger-cat-like state via a coherent superposition of photonic operations

We propose an optical scheme to generate a superposition of coherent states with enhanced size adopting an interferometric setting at the single-photon level currently available in the laboratory. Our scheme employs a nondegenerate optical parametric amplifier together with two beam splitters so that the detection of single photons at the output conditionally implements the desired superposition of second-order photonic operations. We analyze our proposed scheme by considering realistic on-off photodetectors with nonideal efficiency in heralding the success of conditional events. A high-quality performance of our scheme is demonstrated in view of various criteria such as quantum fidelity, mean output energy, and measure of quantum interference

Effects of pressure on the ferromagnetic state of the CDW compound SmNiC2

We report the pressure response of charge-density-wave (CDW) and ferromagnetic (FM) phases of the rare-earth intermetallic SmNiC2 up to 5.5 GPa. The CDW transition temperature (T_{CDW}), which is reflected as a sharp inflection in the electrical resistivity, is almost independent of pressure up to 2.18 GPa but is strongly enhanced at higher pressures, increasing from 155.7 K at 2.2 GPa to 279.3 K at 5.5 GPa. Commensurate with the sharp increase in T_{CDW}, the first-order FM phase transition, which decreases with applied pressure, bifurcates into the upper (T_{M1}) and lower (T_c) phase transitions and the lower transition changes its nature to second order above 2.18 GPa. Enhancement both in the residual resistivity and the Fermi-liquid T^2 coefficient A near 3.8 GPa suggests abundant magnetic quantum fluctuations that arise from the possible presence of a FM quantum critical point.Comment: 5 pages, 5 figure