Interactive Texturing For a Computer Graphics Display System

Surfaces have texture, and few surfaces are truly smooth in the real world, yet this is how they are modeled. Texturing provides the illusion of increased surface roughness or granularity, and it also gives the illusion of extra detail and realism. This is accomplished by modulating surface color based on gradient function known as texture pattern. Changing texture pattern data can be expensive and time consuming since the change must be done on database offline system and then reloaded on the Computer Image Generator (CIG) for review of the change. The Interactive Generator (IAT) system is designed for online examination and/or modification of the data associated with texture patterns on the General Electric Computer Image Generator (COMPUSCENE III CIG). With this online capability, the IAT system is very cost effective because it facilitates the process of debugging and improving new texture patterns. In this paper, the texture pattern data, specifications of IAT system, interface requirements, the IAT system overview, limitations, measure of performance and future enhancement are described with respect to COMPUSCENE II CIG

Selection mechanisms affect volatility in evolving markets

Financial asset markets are sociotechnical systems whose constituent agents are subject to evolutionary pressure as unprofitable agents exit the marketplace and more profitable agents continue to trade assets. Using a population of evolving zero-intelligence agents and a frequent batch auction price-discovery mechanism as substrate, we analyze the role played by evolutionary selection mechanisms in determining macro-observable market statistics. In particular, we show that selection mechanisms incorporating a local fitness-proportionate component are associated with high correlation between a micro, risk-aversion parameter and a commonly-used macro-volatility statistic, while a purely quantile-based selection mechanism shows significantly less correlation.Comment: 9 pages, 7 figures, to appear in proceedings of GECCO 2019 as a full pape

Physical fitness and activity levels among Chinese people with schizophrenia: A cross-sectional study with matched case-control comparison

People with schizophrenia have an increased risk of developing cardiometabolic diseases and a reduced life expectancy. Studies conducted mainly in Western settings report low amounts of activity and poor levels of fitness in this population. This study aims to compare physical fitness and activity levels between people with schizophrenia/healthy matched controls and investigate potential associations between these variables. A cross-sectional study was conducted with 57 community-dwelling people with schizophrenia and 57 age-, gender- and BMI-matched controls. Participants completed the International Physical Activity Questionnaire and the YMCA Fitness Assessment Protocol with accompanying cardiovascular/lung function tests. Cardiorespiratory fitness was significantly better in healthy matched controls than individuals with schizophrenia in all areas (all p<.05, d=0.38 to 1.06). Performance in best trunk flexion, half sit-ups and one-minute pulse recovery following the 3-minute step test were significantly worse in the schizophrenia group (all p<.001, d=0.76 to 1.04). Higher levels of weekly moderate activity (t=-2.66, p=.009) and total weekly activity levels (t=-2.013, p=.047) were reported by the healthy controls. Levels of vigorous activity were significantly correlated with some areas of lung functioning in the schizophrenia group (all p<.05). The findings show that Chinese people with schizophrenia have significantly poorer fitness than matched healthy controls, demonstrating the need to provide timely effective exercise-based interventions as a matter of routine to attenuate the risk of developing chronic physical illnesses

Exponential suppression of thermal conductance using coherent transport and heterostructures

We consider coherent thermal conductance through multilayer photonic crystal heterostructures, consisting of a series of cascaded non-identical photonic crystals. We show that thermal conductance can be suppressed exponentially with the number of cascaded crystals, due to the mismatch between photonic bands of all crystals in the heterostructure.Comment: 15 pages, 4 figure

Noise generation by shock-turbulence interaction

October 1970Includes bibliographical references (leaf 10)The noise produced by convection of turbulence through an oblique shock wave has been measured and compared to theoretical predictions by Ribner and Kerrebrock. There is excellent agreement with the theoretical prediction that, for a fixed turbulent input, the downstream noise pressure (divided by the mean pressure), should first increase very rapidly, and then decrease as the normal Mach number of the shock is increased from unity to values of the order of 1.5. This behavior implies that a part of the noise from supersonic jets should behave similarly, with a sharp increase, then a decrease as the nozzle pressure ratio is raised from unity.This Research Carried Out in the Gas Turbine Laboratory, M.I.T., in Cooperation with Lewis Research Center, NASA, under Grant NGL 22-009-38

The Impact of Non-Equipartition on Cosmological Parameter Estimation from Sunyaev-Zel'dovich Surveys

The collisionless accretion shock at the outer boundary of a galaxy cluster should primarily heat the ions instead of electrons since they carry most of the kinetic energy of the infalling gas. Near the accretion shock, the density of the intracluster medium is very low and the Coulomb collisional timescale is longer than the accretion timescale. Electrons and ions may not achieve equipartition in these regions. Numerical simulations have shown that the Sunyaev-Zel'dovich observables (e.g., the integrated Comptonization parameter Y) for relaxed clusters can be biased by a few percent. The Y-mass relation can be biased if non-equipartition effects are not properly taken into account. Using a set of hydrodynamical simulations, we have calculated three potential systematic biases in the Y-mass relations introduced by non-equipartition effects during the cross-calibration or self-calibration when using the galaxy cluster abundance technique to constraint cosmological parameters. We then use a semi-analytic technique to estimate the non-equipartition effects on the distribution functions of Y (Y functions) determined from the extended Press-Schechter theory. Depending on the calibration method, we find that non-equipartition effects can induce systematic biases on the Y functions, and the values of the cosmological parameters Omega_8, sigma_8, and the dark energy equation of state parameter w can be biased by a few percent. In particular, non-equipartition effects can introduce an apparent evolution in w of a few percent in all of the systematic cases we considered. Techniques are suggested to take into account the non-equipartition effect empirically when using the cluster abundance technique to study precision cosmology. We conclude that systematic uncertainties in the Y-mass relation of even a few percent can introduce a comparable level of biases in cosmological parameter measurements.Comment: 10 pages, 3 figures, accepted for publication in the Astrophysical Journal, abstract abridged slightly. Typos corrected in version

Making product decisions in Citra (M) Sdn Bhd

This case describes the dilemma of Citra (M) Sdn Bhd in making product decisions. This dilemma arises as a result of the need to respond to an urgent order of the 14” colour picture tubes from its headquarters in Korea. These tubes were intended to solve the inadequate production problem of Citra (China) whose production had been disrupted by an explosion. On one hand, satisfying this request might disrupt Citra (M) Sdn Bhd’s production plan due to capacity constraints. On the other hand, accepting this order represents an opportunity to tap the vast market in China. Thus, in spite of the capacity constraints and the possible disruption to its production plan, the General Manager of Citra (M) Sdn Bhd asked himself, “How could I possibly reject this order from China?”

Thermal Lattice Boltzmann Simulation for Multispecies Fluid Equilibration

The equilibration rate for multispecies fluids is examined using thermal lattice Boltzmann simulations. Two-dimensional free-decay simulations are performed for effects of velocity shear layer turbulence on sharp temperature profiles. In particular, parameters are so chosen that the lighter species is turbulent while the heavier species is laminar-and so its vorticity layers would simply decay and diffuse in time. With species coupling, however, there is velocity equilibration followed by the final relaxation to one large co- and one large counter-rotating vortex. The temperature equilibration proceeds on a slower time scale and is in good agreement with the theoretical order of magnitude estimate of Morse [Phys. Fluids 6, 1420 (1963)]