Showing papers by "Concordia University published in 1979"
TL;DR: The positional distributions of n-grams obtained in the present study are discussed and statistical studies on word length and trends ofn-gram frequencies versus vocabulary are presented.
Abstract: n-gram (n = 1 to 5) statistics and other properties of the English language were derived for applications in natural language understanding and text processing. They were computed from a well-known corpus composed of 1 million word samples. Similar properties were also derived from the most frequent 1000 words of three other corpuses. The positional distributions of n-grams obtained in the present study are discussed. Statistical studies on word length and trends of n-gram frequencies versus vocabulary are presented. In addition to a survey of n-gram statistics found in the literature, a collection of n-gram statistics obtained by other researchers is reviewed and compared.
237 citations
TL;DR: In this article, the effects of the root radius, the setting angle and the tip mass are incorporated into the finite element model to investigate the vibration frequency of a rotating beam with tip mass.
178 citations
TL;DR: Data appear to rule out activation of the ascending noradrenergic systems as an explanation of the rewarding effects of stimulation in areas supporting self-stimulation, and a gustatory-visceral fiber system is suggested as an alternative possible substrate.
121 citations
TL;DR: A brief survey of the developments in the estimation of seemingly unrelated regression equation models covering a period of one and a half decades, including some of the recent results by the authors, can be found in this article.
104 citations
TL;DR: A complex interaction between the conditioned and unconditioned temperature responses to morphine is suggested.
Abstract: The conditioning of body temperature changes using an injection of morphine sulphate as the conditioned stimulus was studied in 30 male Wistar rats. Three groups of animals received daily i.p. injections of either 5, 25, or an increasing dose to 200 mg/kg morphine; a fourth group received saline injections throughout. Rectal temperature was measured in three different environments five times during the day: in a neutral environment, the home cage; in a pre-injection environment, in which animals were placed for a period before the daily injection; and in an injection environment, in which animals remained after the injection. Conditioning trials were followed by a period of abstinence from morphine. Tests for conditioned effects were carried out both during conditioning and after the period of abstinence. During conditioning, animals in the morphine groups, when compared to the saline control animals, showed a conditioned anticipatory hypothermia in the preinjection environment that was opposite in direction to the unconditioned hyperthermia to morphine. In contrast, in the injection environment, animals in the morphine groups showed a conditioned hyperthermia when tested after the period of abstinence. These results suggest a complex interaction between the conditioned and unconditioned temperature responses to morphine.
101 citations
TL;DR: The results empirically answer the long-standing question of what is the benefit, if any, of using transition probabilities that depend on the length of a word and their position in it.
Abstract: In this paper a modification of the Viterbi algorithm is formally described, and a measure of its complexity is derived. The modified algorithm uses aheuristic to limit the search through a directed graph or trellis. The effectiveness of the algorithm is investigated via exhaustive experimentation on an input of machine-printed text. The algorithm assumes language to be a Markov chain and uses transition probabilities between characters. The results empirically answer the long-standing question of what is the benefit, if any, of using transition probabilities that depend on the length of a word and their position in it.
89 citations
80 citations
TL;DR: The results showed that no enhanced sensory sensitivity is present for these deaf children and questions the classical sensory compensation hypothesis.
Abstract: This experiment compared the visual sensory sensitivity of deaf and hearing subjects in a signal detection paradigm Subjects (ns:= 6) were required to give forced-choice responses to a brightness discrimination task under three stimulus probability conditions (025, 050, and 075) A total of 1,800 trials were given to each subject and utilized to construct isosensitivity functions and d' and Beta, indices for sensory sensitivity and response bias, respectively The results showed that no enhanced sensory sensitivity is present for these deaf children and questions the classical sensory compensation hypothesis Furthermore, the deaf subjects responded in a relatively bias-free manner to variations in stimulus probability
54 citations
TL;DR: Character tables for all the 56 non-abelian simple groups of order up to 106, including three tables for the family PSL(2,q) and twenty tables for individual groups (with some overlap) are presented in this article.
Abstract: Character tables are presented for all the 56 non-abelian simple groups of order up to 106, including three tables for the family PSL(2,q) and twenty tables for individual groups (with some overlap). Information presented includes the power maps, the orders of the centralizers of elements, and tables of structure constants for each class of involutions.
53 citations
TL;DR: In this article, a systematic design procedure for the output filter of a single-phase uninterruptible power supply (UPS) system is developed, and four different output filter configurations are compared for sinusoidal pulsewidth and single-pulse modulated inverter output voltage.
Abstract: A systematic design procedure for the output filter of a singlephase uninterruptible power supply (UPS) system is developed. The basic specifications for the UPS system are first established. Four different output filter configurations are then analyzed and compared for sinusoidal pulsewidth and single-pulse modulated inverter output (i.e., filter input) voltage. On the basis of the above comparison, ``optimum'' filters are selected for both modulation techniques. Using a minimization function for filter cost and size, a set of filter design parameters corresponding to each type of modulation are obtained on the per unit basis. The theoretical results are verified on an experimental breadboard utilizing a current commutated thyristor inverter. Finally, the overall filter design procedure is outlined and a design example is presented.
52 citations
TL;DR: In this article, the authors used cross-section data from individual establishments to estimate directly, without using side conditions, translog functions for 44 four-digit ISIC Chilean manufacturing industries.
TL;DR: These results contain the standard "single-loop" passivity results as special cases, and are in some ways simpler to apply than the large-scale results found elsewhere.
Abstract: In this paper, we present several new passivity-type criteria for the L 2 -stability and L 2 -instability of large-scale interconnected systems. These results contain the standard "single-loop" passivity results as special cases, and are in some ways simpler to apply than the large-scale results found elsewhere.
TL;DR: In this paper, a modified phase-commutated converter with an improved power factor was presented and analyzed for both rectifying and inverting modes, and the optimal power factor firing control was formulated while taking into account commutation overlaps.
Abstract: A modified phase-commutated converter with an improved power factor (PF) is presented and is analyzed for both rectifying and inverting modes. The optimal power factor firing control is formulated while taking into account commutation overlaps. Different modes of converter operation are identified and are analyzed in terms of reactive power requirements, power factor, and harmonic distortion on both ac and dc sides. The results are used to compare critically the new converter with a conventional six-pulse bridge.
01 Mar 1979-International Journal of Human-computer Studies \/ International Journal of Man-machine Studies
TL;DR: A combined bottom-up top-down algorithm is proposed and exhaustive experimentation shows that the algorithm achieves the error-correcting capability of the dictionary look-up methods at half the cost.
Abstract: Existing approaches to using contextual information in text recognition tend to fall into two categories: dictionary look-up methods and Markov methods. Markov methods use transition probabilities between letters and represent a bottom-up approach to using context which is characterized by being very efficient but exhibiting mediocre errorcorrecting capability. Dictionary look-up methods, on the other hand, constrain the choice of letter sequences to be legal words and represent a top-down approach characterized by impressive error-correcting capabilities at a stiff price in storage and computation. In this paper, a combined bottom-up top-down algorithm is proposed. Exhaustive experimentation shows that the algorithm achieves the error-correcting capability of the dictionary look-up methods at half the cost.
TL;DR: New techniques for solving extremely stiff systems of differential equations based on a class of implicit Runge-Kutta procedure with complete error estimate are proposed and applied to solving mathematical models of the relaxation problem behind blast waves.
TL;DR: The formal part of a theorem-proving system for automating mildly complex proofs by structural induction is presented, which includes a typed language and an induction rule using a lexicographic ordering based on a substructure ordering.
TL;DR: In this paper, the isomorphism classes of simple groups of order up to 106 distinct from PSL(2,q) are presented in the form G = where m is minimal (with respect to a) and complete in the sense that any pair of generators of G satisfying the relations a2 = bm = 1, with m minimal, will satisfy the defining relations of just one presentation listed here.
Abstract: Of the 56 isomorphism classes of simple groups of order up to 106 there are 10 of order up to 105 distinct from PSL(2,q). Presentations for these groups are given here in the form G = where m is minimal (with respect to a). They are complete in the sense that any pair (a, b) of generators of G satisfying the relations a2 = bm = 1, with m minimal, will satisfy the defining relations of just one presentation listed here.
TL;DR: In this paper, a digitally controlled current source based on a 6-pulse thyristor bridge is described, where the source is amenable to direct microprocessor control when part of a larger system, and a new method for zero voltage detection and configuration and analysis of a digital proportional-integral (PI) controller are presented.
Abstract: A digitally controlled current source, based on a 6-pulse thyristor bridge is described. When part of a larger system, the source is amenable to direct microprocessor control. Salient aspects of the design described here are a new method for zero voltage detection and the configuration and analysis of a digital proportional-integral (PI) controller. The paper gives the design procedure as well as the experimental results obtained on the actual current source.
TL;DR: In this article, the authors examined a firm's relationships with its environment as inter-organizational relationships and found that market and non-market relationships are structurally similar, and the same types of strategic responses can be selected for both areas.
TL;DR: A theorem-proving system has been programmed for automating mildly complex proofs by structural induction, which can cope with situations as complex as the defination and correctness proof of a simple compiling algorithm for expressions.
TL;DR: The present paper analyzes the court transcript of a recent case in Australia in which a lay hypnotist was found guilty of 3 sexual offenses against 2 female clients and pits the 2 main positions on hypnotic coercion against each other.
Abstract: There are 2 main positions concerning the potential of hypnosis to coerce unconsenting behavior. One position asserts that coercion is possible through the induction of distorted perceptions which delude the hypnotized person into believing that the behavior suggested is not transgressive. The other position asserts that where hypnosis appears to be a causal factor in coercing behavior, other elements in the situation- especially a close hypnotist-client relationship-were the main determinants of behavior. The present paper analyzes the court transcript of a recent case in Australia in which a lay hypnotist was found guilty of 3 sexual offenses against 2 female clients. The uniqueness of the case is that it pits the 2 main positions on hypnotic coercion against each other. The hypnotist admitted the acts attributed to him; his defense was that hypnotic coercion is impossible since a hypnotized person would resist immediately any transgressive suggestion. The women involved stated that they were a...
01 Dec 1979
TL;DR: In this article, a simple form of the extended Kalman filter, where the state consists only of the parameters to be estimated, is proposed, based on the inclusion of the computed residuals in the observation matrix of a state representation of the system, an idea first introduced in the extended least squares or Panuska's method.
Abstract: A well-known method for estimation of parameters in linear systems with correlated noise is the extended Kalman filter where the unknown parameters are estimated as a part of an enlarged state vector. To avoid the computational burden in determining the state estimates when only the parameter estimates are required, a new simple form of the extended Kalman filter, where the state consists only of the parameters to be estimated, is proposed. The algorithm is based on the inclusion of the computed residuals in the observation matrix of a state representation of the system, an idea first introduced in the so-called extended least squares or Panuska's method. Convergence properties of the proposed algorithm are studied and the algorithm is shown to perform a gradient-based minimization of the maximum likelihood loss function. Some special cases of the algorithm are also discussed and an extension to an estimator for randomly varying parameters is outlined.
TL;DR: In this paper, a systematic procedure for the dynamic analysis of planar mechanisms with multiple clearances is presented, where each link of the mechanism is considered as a rigid member, and contact modes are detected by iteration according to the inequalities of input torque and pin forces.
Abstract: A systematic procedure for the dynamic analysis of planar mechanisms with multiple clearances is presented. Each link of the mechanism is considered as a rigid member, and contact modes are detected by iteration according to the inequalities of input torque and pin forces. The method is useful for predicting the number and frequency of contacts and separations occurring in the mechanism-joints for one complete cycle of the input crank.A four-bar mechanism is used to illustrate the procedure. Results show that there are significant changes in accelerations, torque and pin forces as compared with the case without clearances. Minimal changes have been detected in displacement and velocity relationships.The model presented in the paper provides a design method for investigating torque requirements, pin forces and separation occurrences in high-speed machines with clearance.
TL;DR: A role for the androgenic actions of testosterone in establishing sex differences in nonreproductive behavior in the rat was discussed in terms of a role for its major metabolites, dihydrotestosterone (DHT) and estradiol (E2), on the development ofsex differences in open-field behavior.
TL;DR: Nymphs of Paragnetina media were able to tolerate a range of salinities in the external media up 1.1% NaCl, and nymphs maintained in distilled water showed excellent osmoregulation by producing hyposmotic urine.
01 Jun 1979
TL;DR: In this paper, an annular shock tube is fitted with axisymmetric area contraction, which redirects an incident shock into a cylindrical implosion chamber, and the contraction profile is designed in accordance with Whitham's ray-shock theory, and a three-element profile is found to provide the best overall performance on the basis of twodimensional tests.
Abstract: AN improved experimental technique for the production of cylindrical converging shock waves is presented. This is accomplished with an annular shock tube fitted with an axisymmetric area contraction which redirects an annular incident shock into a cylindrical implosion chamber. The contraction profile is designed in accordance with Whitham's ray-shock theory, and a three-element profile is found to provide the best overall performance on the basis of twodimensional tests. Experiments with a three-element conical contraction demonstrate that highly symmetrical cylindrical implosions may be achieved by this method, and that the cylindrical shock amplification is well predicted by the Chester-Chisnell-Whitham (CCW) area Mach No. rule.
TL;DR: In this paper, a general predictive distribution is given, to predict a statistic in the future sample based on the statistics in the earlier samples (or stages), and an illustrative example with simulated samples from an exponential population is given.
Abstract: A series of independent samples are drawn from a general population with positive variationf(x,ϕ), x>0. Based on the Bayesian approach, a general predictive distribution is given, to predict a statistic in the future sample based on the statistics in the earlier samples (or stages). Few general classes of distributions of this type like Koopman-Pitman family, power function family and Burr's class of distributions are considered to show how this procedure works in predicting order statistics in the future sample. Also, the sum of the spacings in the future samples from an exponential population is predicted in terms of similar sum of spacings in the earlier samples. Discussion on the variance of this predictive distribution is dealt with. Finally, an illustrative example with simulated samples from an exponential population gives actual prediction of an order statistic as well as the sum of spacings in the future sample.