Robert D. Clear

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An efficient ray tracing method is presented for calculating interreflections between surfaces with both diffuse and specular components. A Monte Carlo technique computes the indirect contributions to illuminance at locations chosen by the rendering process. The indirect illuminance values are averaged over surfaces and used in place of a constant "ambient"(More)
Time-averaged human electroretinogram (ERG) responses were determined for several workplace visual stimuli which are temporally modulated at rates exceeding the perceptual critical fusion frequency (CFF). A clearly identifiable synchronous response was in evidence for a video display terminal (VDT) stimulus operating with a refresh rate as high as 76 Hz. A(More)
A prototype integrated, dynamic building envelope and lighting system designed to optimize daylight admission and solar heat gain rejection on a real-time basis in a commercial office building is evaluated. Office worker response to the system and occupant-based modifications to the control system are investigated to determine if the design and operation of(More)
Environmental Protection Agency (EPA) ambient air quality guidelines are meant to limit long-term exposures of toxins to safe levels. Unfortunately, there is little guidance for what constitutes a safe level from a one-time (or very infrequent) short exposure(s). In the case of mercury, a review of the derivation of the EPA ambient air quality standard(More)
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