Efficient Reflectance and Visibility Approximations for Environment Map Rendering

We present a technique for approximating isotropic BRDFs and precomputed self-occlusion that enables accurate and efficient prefiltered environment map rendering. Our approach uses a nonlinear approximation of the BRDF as a weighted sum of isotropic Gaussian functions. Our representation requires a minimal amount of storage, can accurately represent BRDFs of arbitrary sharpness, and is above all, efficient to render. We precompute visibility due to self-occlusion and store a low-frequency approximation suitable for glossy reflections. We demonstrate our method by fitting our representation to measured BRDF data, yielding high visual quality at real-time frame rates.     

Analysis and comparison of real-time sine-wave generation for PWMcircuits

Four methods for hardware and software generation in real time of sine waves suitable for PWM circuits are presented. The sine waves are derived from a truncated modified cosine Taylor series, wt(π-wt) function, a digitally filtered trapezoid, and a second-order differential equation. Triplen injection is incorporated by the addition of a defined magnitude triangular waveform of three times the fundamental frequency. Each sine wave generating technique is implemented, as applicable, in a programmable logic cell array and/or in microprocessor-based software. In each case, the output spectra and total harmonic distortion are compared with computer-simulated results     

Effect of atherogenic diet on chicken plasma lipids and lipoproteins

Adult male White Leghorn chickens were used in an experimental model system to study atherogenesis, and the effects of an atherogenic diet on plasma lipoprotein composition including carotenoids were determined. This model also included treatment with diazepam, a drug known to reduce formation of atherogenic plaques. After 6 wk consumption of a high-cholesterol, high-triglyceride diet, chickens had mean total plasma cholesterol, triglyceride, and carotenoid concentrations that were significantly increased over those from chicks that consumed the standard diet. Diazepam treatment had no significant effect on whole plasma concentrations of these lipids. Total body weight gain was unaffected by diet, but liver weight expressed as percentage of body weight was significantly increased in chickens that consumed the atherogenic diet. High density lipoprotein (HDL) and low density lipoprotein (LDL) fractions were isolated from plasma samples by ultracentrifugation. The atherogenic diet increased the carotenoid, cholesterol, and protein content of the LDL fractions but not the HDL fractions.     

Top management support of R&D projects: a strategic leadershipperspective

A study of top management support of 213 R&D projects in 21 major firms revealed significant relationships between independent informants' perceptions of top management support, project characteristics, and project performance. Testing a model based on a strategic leadership perspective, top management support was found to be directed at certain types of projects, i.e., those that were expected to make greater contributions to business goals, represented larger investments, were seeking new products and process versus incremental improvements, and had originated from business sources as opposed to R&D. In addition, even after controlling for these project characteristics, projects with top management support were less likely to be terminated. In contrast, after controlling for project characteristics, completed projects with top management support were not judged to make greater contributions to the firm's business goals suggesting top management may not be able to pick winners. Findings are discussed in terms of future research and implications for top management leadership within R&D     

Policy Analysis, Peer Reviewed: Evaluation of Bioaccumulation Factors in Regulating Metals

Regulations.     

A strain hardening failure assessment diagram derived from carbon-manganese steel compact tension specimens

A failure assessment diagram is derived from carbon-manganese steel compact tension specimens. The diagram has been determined from an elastic-plastic finite element analysis of a compact tension specimen geometry. The diagram has been validated by using experimental fracture toughness data obtained on the same steel and specimen geometry modelled in the finite element analysis. The plastic collapse load has been determined empirically for this geometry.It is shown that a non-work-hardening failure assessment diagram is not a good representation of the experimental data and that the computed failure assessment diagram is more appropriate for describing the behaviour of the carbon-manganese steel specimens.     

Prediction of psychoticlike symptoms in hypothetically psychosis-prone college students.

Correlates of psychotic and psychoticlike symptoms were examined in 60 college students who scored deviantly high on the Perceptual Aberration Scale. High scorers on this scale who also scored high on both the Impulsive Nonconformity Scale and the Depression subscale of the General Behavior Inventory (GBI) showed the most deviant psychotic and psychoticlike symptoms. Moreover, performance on a task of referential communication, the Password Task, was significantly related to such symptoms. The Perceptual Aberration Scale, the Impulsive Nonconformity Scale, and the GBI Depression subscale are recommended for concurrent use in mass screening to select individuals likely to exhibit psychotic or psychoticlike symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specifying transformer winter and summer peak-load limits

This paper presents a methodology for specifying the winter and summer peak-load limits for substation transformers that carry a temperature-sensitive load, taking into account the random nature of load and ambient temperature as well as their correlation. With this methodology, we can easily and accurately specify the peak-load limits for each substation transformer once the historical ambient temperature and load data are available. Also, we can collectively specify the peak-load limits for the transformer of each cooling type (OA, OA/FA, or OA/FA/FA) in a geographic region based on the mean and standard deviation of ambient temperatures in that region. Such peak-load limits are useful for power system planning.