Two-dimensional matches from one-dimensional stimulus components in human stereopsis

Three-dimensional visual scenes project onto the retina of the eye as two-dimensional images. The third dimension, depth, is projected as subtle differences between left and right retinal images. As early as the 1830s, stereoscopic depth perception was shown to depend on horizontal disparities between these images. To detect disparity, the visual system must match corresponding parts of the two retinal images. To identify the stimulus elements used in stereo matching, I applied a disparity-adaptation technique to visual patterns whose one-dimensional components and two-dimensional features have very different disparities. Surprisingly, the adaptors that are effective in altering depth perception appear widely separated in depth from the patterns they adapt. I conclude that stereo matching occurs in all directions of two-dimensional space and that one-dimensional components are the stimulus primitives, the fundamental elements of stereo matching. This is a reversal of the classical view of stereo correspondence as a one-dimensional (horizontal) matching of monocular two-dimensional features.     

90 Mbit/s Digital Performance of Canada's 14/12 GHz ANIK C Earth Stations

The design and performance aspects of Canada's first commercial 14/12 GHz ANIK C earth stations are reviewed, with particular reference to the satellite link degradations of the 90 Mbit/s digital message service. Following design considerations based on computer simulations, extensive test data are presented with respect to BER, jitter, and other performance characteristics of the loop closed via. an ANIK C satellite simulator (SS). An analysis of the effects of linear and nonlinear distortions is applied to the formulation of a model that provides insight into the practical quantitative assessment of field tolerance and maintenance limits and of tradeoffs for new digital transmission systems.     

Composition Control of a Bleach Saturator

A common item of equipment in the textile industry, the saturator has been overlooked in the implementation of quality-control programs throughout textile manufacturing. Although these unit operations appear to be simple in nature, interactions between process variables, changes in cloth density and flow rate, process deadtimes, and non-linearities (such as pH) frequently cause transients which adversely affect cloth consistency. A properly designed control system will reduce process variation by addressing these phenomena and thus dramatically improve the consistency of the final product. A simple saturator model is developed, and a control system is designed by using classical feedforward and Smith Predictor elements. The control system has minimal complexity but maintains saturator compositions within reasonable control limits.     

Comparison requirements and attention in identical-nonidentical stimulus discriminations.

Perceptual matching data show several puzzling effects. Particularly problematic are the disparities between the processing rates for same and different stimuli—the fast–same effect—and between the processing rates for two same–different judgment tasks that are related as mirror images—the task effect. Current models have difficulty accounting simultaneously for both effects. Central to these models is a stimulus comparison process that derives relative judgments of sameness and difference from tests of the congruence of stimulus representations. A contrasting view holds that same–different judgments can be modeled as absolute, rather than relative, judgments. This latter view is shown to be supported by experimental data. Reaction times (RTs) for judgments of identical letter strings increase with string length at the same rate whether judgments are based on all the information in the strings or just the information in a single pair of component letters. The data show that stimulus comparisons of the sort described by previous models are not involved in these judgments. An attentional model accounts for the data and for the fast–same and task effects as well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Same"–"different" judgments: A review of current controversies in perceptual comparisons.

Reviews the literature on 2 anomalous effects, the "fast-same" effect (FSE) and the criterion effect, found in the interpretation of same–different reaction-time data. No 2 models localize the FSE in the same information-processing stage or attribute the phenomenon to a common stimulus property or task demand. It is suggested that each of the models, or some combination of them, may account for particular instances of the FSE. Findings show that disjunctive same–different judgments differ from conjunctive judgments in both quantitative and qualitative respects. The criterion effect rules out models in which a dimensional comparison process underlies conjunctive different judgments, for such models have no provision for making disjunctive judgments contingent on a different process. It has been suggested that feature matching might be amenable to criterion-contingent processing modes, forming the basis of a unified model of same–different judgments. Another approach takes the view that the conjunctive same response is an absolute, rather than relative, judgment, giving rise to an attentional model. (4? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic matrix control of diaphragm-type chlorine/caustic electrolysers

Dynamic matrix control (DMC) is now widely used in industrial control, and when properly applied results in significant savings due to improved efficiency and reduced off-spec product. The objective of this paper is to implement MIMO DMC on a simulated diaphragm-type chlorine/caustic electrolyser. A comparison between the MIMO DMC and traditional multi-loop SISO PID control strategy shows greatly improved controller performance and cell efficiency using DMC, which will result in reduced operating costs and increase cell diaphragm lifespan.     

Why use noise?

Measuring the dependence of visual sensitivity on parameters of the visual stimulus is a mainstay of vision science. However, it is not widely appreciated that visual sensitivity is a product of two factors that are each invariant with respect to many properties of the stimulus and task. By estimating these two factors, one can isolate visual processes more easily than by using sensitivity measures alone. The underlying idea is that noise limits all forms of communication, including vision. As an empirical matter, it is often useful to measure the human observer's threshold with and without a noise background added to the display, to disentangle the observer's ability from the observer's intrinsic noise. And when we know how much noise there is, it is often useful to calculate ideal performance of the task at hand, as a benchmark for human performance. This strips away the intrinsic difficulty of the task to reveal a pure measure of human ability. Here we show how to do the factoring of sensitivity into efficiency and equivalent noise, and we document the invariances of the two factors.