Orthogonal Ones Research Articles

Developing an empirical model for dewatering — And its application to peat

This paper contains two main topics: a strategy for finding optima in general experimentation and examples of using this strategy for the dewatering of peat. For optimising experimental conditions of industrial processes, the relation between design variables and response variables has been studied. For accommodating the possibility of detecting and describing nonlinearities, the design variables have been augmented with their square and interaction terms. Use is made of response surface methodology. The way of expressing the relation is by regression coefficients obtained from partial least square regression. The design uses more levels than the usual factorial or fractional factorial ones. This requires the use of almost-orthogonal designs in the design's variables (instead of the usual orthogonal ones) in order to limit the number of experiments. A computer program was developed to allow the construction of design with minimal correlation. The response surfaces were validated using extra experiments, and the results of this were satisfying, showing the validity of the surface obtained. The strategy was tried for dewatering of peat by filtration of a slurry followed by pressing the filter cake. Here, the traditional deterministic laws for filtration were replaced by an empirical approach resulting in parameters obtained from experiments.

Gaussian ensembles of random hermitian matrices intermediate between orthogonal and unitary ones

A Gaussian ensemble of Hermitian matrices depending on a parameter α is considered. When α=0, the ensemble is Gaussian Orthogonal, and when α=1, it is Gaussian Unitary. An analytic expression for then-level correlation and cluster functions is given for anyn and 0≦α≦1. This ensemble is of relevance in the study of time reversal symmetry breaking of nuclear interactions.

Algorithms for covering polygons by rectangles

The polygons on the pattern generator used to produce masks for integrated circuits must be covered by the smallest possible number of rectangles. Two algorithms were elaborated to enable this task to be computerized. One of these algorithms is for general polygons, the other for orthogonal ones - the latter is quicker and more effective. Examples are given to demonstrate the effectiveness and the processing time of the program, which is part of the designer system for microelectronics (MICAD) elaborated at the Central Research Institute for Physics of the Hungarian Academy of Sciences.

Motion and vision. IV. Isotropic and anisotropic spatial responses.

When the thresholds for periodic spatial patterns containing two or more differently oriented components (e.g., crossed gratings) are measured under normal, unstabilized conditions, each component seems to be detected almost independently of the others if their angular orientations are sufficiently different. This psychophysical behavior has been attributed to anisotropic or orientation-tuned units in the visual cortex. Here we report that when the image of such a multicomponent pattern is stabilized on the retina, the independent-detection behavior vanishes. Under stabilized-image conditions, the contrast sensitivity is governed by the maximum local contrast at the retina. The number and relative contrast of individual components, even orthogonal ones, behave almost additively in making up the threshold contrast. We confirmed this conclusion with a variety of patterns that give orientation-tuning effects in unstabilized viewing. Controlled image motion (resembling the effect of the natural drifts of the eye) restores the independent-detection behavior in every case, as do other forms of temporal modulation (e.g., flicker or flash presentations). We infer (1) that orientation-tuned units in man do not respond to unchanging stimuli--they cannot function unless the pattern on the retina is temporally modulated, and (2) in the absence of temporal modulation, spatial patterns are detected by isotropic units of relatively low sensitivity.

A resolver for simulating twelve normal leads from three corrected orthogonal ones

A resolver for simulating twelve normal leads from three corrected orthogonal ones

Current Status of Multiple Comparisons of Means in Designed Experiments

Procedures for differentiating means in designed contrasts and post-data comparisons are appraised on recent evidence on sensitivity (power) and degree of protection of type I error rate. Orthogonal f-tests, Bonferroni t-statistics, Scheffé’s interval, Tukey's Honestly Significant Difference, Student-Newman-Keuls procedure, Duncan's Multiple range test, Least Significant Difference, and Dunnett's t-test are discussed. Designed contrasts (especially orthogonal ones) permit use of tests more sensitive than those recommended for testing of comparisons selected post-data. If one must resort to all possible pair-wise comparisons, then Tukey's Honestly Significant Difference test (or possibly the Student-Newman-Keuls procedure) should be used to avoid the large inflation of type I error rate incurred by Least Significant Difference of Duncan's test. Examples of applications of recommended techniques are given.