Showing papers by "University of Winnipeg published in 1994"

A generalized fuzzy Petri net model

Abstract: The paper proposes a new model of Petri nets based on the use of logic based neurons. In contrast to the existing generalizations, this approach is aimed at neural-type modeling of the entire concept with a full exploitation of the learning capabilities of the processing units being used there. The places and transitions of the net are represented by OR and AND-type and DOMINANCE neurons, respectively. A correspondence between this model and the previous two-valued counterpart is also revealed. The learning aspects associated with the nets are investigated. >

Dimensions of perfectionism and suicide ideation

Abstract: Two studies were conducted to examine the relation between dimensions of perfectionsim and suicide ideation: whether perfectionism is important in suicide ideation when considered in the context of other predictors of suicide (i.e., depression, hopelessness), and whether perfectionism moderates the association between life stress and suicide ideation. Samples of 91 psychiatric patients (Study 1) and 160 college students (Study 2) completed the Multidimensional Perfectionism Scale, the Hopelessness Scale, the Beck Depression Inventory, and the Scale For Suicide Ideation. The subjects in Study 2 also completed a measure of negative life stress. Overall, the results confirmed that self-oriented and socially prescribed perfectionism are associated with greater suicide ideation. Moreover, these two perfectionism dimensions contributed uniquely to the discrimination of suicide groups and both moderated the link between life stress and suicide ideation. The findings are discussed in terms of their practical and theoretical implications.

Configural and elemental strategies in predictive learning.

Abstract: When 2 cues occur together and reliably predict an outcome, Ss often judge the effect of the compound as reducible to the individual effects of the elements. This elemental processing in predictive learning is perhaps the single most important aspect of most theories of human inference. Surprisingly, selectional processing was not observed in either blocking or conditioned inhibition problems. Only when the learner had past experience with another problem encouraging an elemental strategy were the expected selectional processes observed. These proactive effects of prior learning were abolished if the earlier problem required a nonadditive solution. The results suggest that configural cues were guiding predictive inferences in the absence of elemental processes

Detection of bandlimited signals over frequency selective Rayleigh fading channels

Abstract: Presents sequence estimation for the frequency selective Rayleigh fading channel. Maximum likelihood estimation using the Viterbi algorithm (MLSE-VA) and sequential sequence estimation (SSE) are developed. Both MLSE-VA and SSE consist of a set of Kalman filters which estimate the fading channel as time evolves. Computer simulations for two different channel models show that the error performance of the two approaches is essentially the same. SSE however has considerably less computational complexity than MLSE-VA. To improve the error performance, diversity is combined with both MLSE-VA and SSE. The simulations show that diversity results in a signal to noise ratio gain of greater than 10 dB. >

Dynamic performance of static and synchronous compensators at an HVDC inverter bus in a very weak AC system

Abstract: This paper discusses the performance of dynamic voltage control devices at the inverters of very weak AC power systems The types of compensation considered are: (a) static VAr compensators (SVC); (b) synchronous compensators (SC); (c) a mix of the two; and (d) fixed capacitors Although the primary purpose of these compensators is to control voltage at the AC bus, their dynamic performance during system disturbances is a very important factor The investigation includes the behavior of the various voltage control options under AC and DC disturbances The paper shows that the SVC has the fastest response for load rejection type of overvoltages, but can cause serious problems with recovery during undervoltages caused by single phase faults The CIGRE benchmark model for HVDC control studies has been modified and used in this study In particular the effect of local load has been included >

Detecting arcing downed-wires using fault current flicker and half-cycle asymmetry

Abstract: The downed-wires problem, known as high impedance faults, is described. A high voltage laboratory setup was devised to investigate the phenomenon. The laboratory model results agreed with field test results, and previous research efforts. The arcing fault model was justified. The setup was used as a source of fault current signal. A simple approach was taken to design an arcing fault detector. The algorithm utilizes the random behavior of the fault current. It compares the positive and negative current peaks in one cycle to those in the next cycle to measure the flicker in the current signal. The asymmetry of the current is calculated by comparing the positive peak to the negative peak, for each cycle: the moving window length is half a cycle. Both values are used as a signature of arcing. The result is filtered and compared with a suitable detection threshold. The algorithm was tested by traces of normal load, and no-load current disturbed by currents of faults on dry and wet soil, arc welders, computers, and fluorescent light loads, as well as short circuit currents. The algorithm performed well under the test conditions, except for the arc welder load. This load is also a source of insecurity for other algorithms. The detection criterion will be integrated with another detection method to improve the security during arcing load events. >

New stacked microstrip antenna with large bandwidth and high gain

Abstract: A new radiating element is presented, which can provide simultaneously a large bandwidth and high gain. It consists of four identical patches uniformly displayed within a rectangular aperture (2*2) and fed electromagnetically by a driven patch etched on a lower substrate. It is shown that a good coupling with the parasitic patches is obtained, causing a large bandwidth, and the resonance modes of each patch are excited in phase, giving a high gain.

Prototype-based assessment of laypeople's views of love.

Abstract: Empirical work on love has focused mainly on romantic/passionate love. Recent research suggests that other kinds of love, such as friendship love and familial love, may be more salient to laypeople (Fehr & Russell, 1991). One purpose of this research was to offer a more complete picture of how laypeople conceptualize love by exploring a broad range of types of love. The other major purpose was to develop a methodology for studying laypeople's conceptions of different kinds of love. Four studies were conducted. In Study 1, dating couples were presented with prototypes of 15 different types of love. They were asked to rate how similar the conception of love depicted in each prototype was to their own view of love. Study 2 was a replication of Study 1 with subjects who were not dating one another. In Study 3, the validity of the prototype measures was explored by asking subjects to determine the kind of love depicted in each prototype. Study 4 investigated the relation between the prototypes of love and existing love scales and therefore addressed issues of convergent and discriminant validity. These prototype-based measures showed considerable promise as valid, reliable instruments for assessing people's views of love. They revealed that laypeople regard friendship love and familial kinds of love as closest to their own view. Passionate kinds of love (e.g., passionate, infatuation, puppy love) received the lowest ratings. The measures also proved useful in elucidating the relation between laypeople's and experts' conceptions of romantic and passionate love.

Atiachment Style and Heterosexual Relationships among Young Adults: A Short-Term Panel Study

Abstract: We investigated whether the relationship advantages reported for individuals with a secure attachment style persisted over a 4-month time period. The temporal stability of two self-report measures of attachment style was also investigated. `Secures' reported consistent levels of relationship satisfaction, relationship costs, relationship commitment, trust for their partners. `Insecures' (i.e. avoidants and anxious/ambivalents) reported decreasing levels of satisfaction, commitment and trust along with increasing relationship costs. Insecurely attached individuals from ended relationships characterized their relationships more negatively than insecures from intact relationships. Both self-report measures of attachment style were characterized by considerable short-term temporal stability.

Life-History Consequences of Avian Brood Reduction

Abstract: -Studies of avian brood reduction characteristically focus on the short-term consequences of hatching asynchrony for offspring (e.g. number and sizes of fledglings), but a truly comprehensive brood-reduction theory needs to incorporate long-term fitness effects for parents if trimming family size leads to lessened parental effort thereafter. A simple model shows that a brood-reduction strategy is more likely to be favored by natural selection when early losses of one or more brood members in poor years (expedited by parental manipulation of hatching asynchrony) lead to significantly diminished parental work levels. Field workers should design experiments to assess the effects of brood reduction on parental work levels, parental survivorship, and/or future fecundity; they could do so simply by borrowing the experimental field techniques already employed in studies of avian reproductive costs. Received 9 February 1993, accepted 10 May 1993. DAVID LACK (1947, 1954) suggested that parent birds may create more offspring than they can normally rear as a hedge against uncertain food. By starting incubation before laying has been completed, parents handicap last-hatched offspring, facilitating their selective elimination if food proves short. Conversely, when food is bountiful, the full brood may be reared. Lack's hypothesis has attracted considerable attention in recent years. Field tests are easily performed, usually involving experimental manipulation of the normal pattern of hatching intervals followed by measurement of the consequences for number and quality of surviving offspring. The results of such work appear uneven and have spawned considerable controversy (Clark and Wilson 1981, Amundsen and Stokland 1988, Magrath 1990, Amundsen and Slagsvold 1991, Pijanowski 1992, Konarzewski 1993, Forbes and Mock 1994). Experiments on the value of hatching asynchrony have focused mostly on how differing reproductive strategies affect recruitment from the current brood. In this regard they parallel the literature on another classic Lack hypothesis, his model of optimal clutch size. There he suggested that parent birds should not maximize the number of nestlings in each breeding attempt, but rather should maximize the number of offspring surviving to recruit into the breeding population (Lack 1954, 1966, 1968). Fundamental to this argument is a trade-off between the number and quality of offspring in a given brood. Although few would argue that Lack's clutch-size model did not represent an important conceptual development, it was quickly recognized as being incomplete. In part, its failure to account for all observed variation inspired refinements of the basic model, most notably recognition that parental reproductive costs may favor smaller clutch sizes (Williams 1966a, b, Charnov and Krebs 1974). Although Lack's hatching-asynchrony hypothesis (usually called the brood-reduction hypothesis, following Ricklefs 1965) predates his clutch-size model, it has not undergone similar scrutiny and amendment. Indeed, the brood-reduction hypothesis per se received little formal theoretical attention until relatively recently (Temme and Charnov 1987, Forbes 1991a, b, Forbes and Ydenberg 1992, Pijanowski 1992, Konarzewski 1993). These contributions have added much-needed mathematical rigor to the original argument, while exploring the roles of environmental variability, sibling rivalry, predation, and egg failure, as well as the cost of tracking variable resources on the evolution of brood-reduction strategies. Not surprisingly, field studies of hatching asynchrony and brood reduction have maintained the same short-term focus. Lack's broodreduction hypothesis is characteristically tested by perturbing the degree of hatching asynchrony (the presumed parental manipulation), then assessing how broods with trimmed (and sometimes exaggerated) hatching spreads compare with sham-manipulated control broods in terms of fledgling production. The rationale for this protocol is simple: the Lack argument predicts that synchronized broods should exhibit

Transformations of real-time finite-temperature Feynman rules.

Abstract: We consider transformations of the 2[times]2 propagator matrix in real-time finite-temperature field theory, resulting in transformed [ital n]-point functions. As special cases of such a transformation we examine the Keldysh basis, the retarded/advanced [ital RA] basis, and a Feynman-like [ital F[bar F]] basis, which differ in this context as to how economically'' certain constraints on the original propagator matrix elements are implemented. We also obtain the relation between some of these real-time functions and certain analytic continuations of the imaginary-time functions. Finally, we compare some aspects of these bases which arise in practical calculations.

Factors affecting pheromone production in beetles

Abstract: Pheromone production and/or release by beetles is coordinated with a variety of behavioral, physiological, and environmental factors. To data, two basic mechanisms for the regulation of pheromone biosynthesis in beetles have been proposed. Pheromone biosynthesis may simply be dependent on the availability of biosynthetic precursors. Alternatively, certain stimuli or events may trigger pheromone biosynthesis via juvenile hormone (JH) action. JH may either act directly at the site of pheromone biosynthesis to enhance pheromone production or may act indirectly, through a brain hormone (which might be related to the pheromone biosynthesis activating neuropeptide) or through effects on antennal sensory response. Knowledge of the regulation of the initiation and termination of pheromone biosynthesis is reviewed. Mechanisms by which pheromone stereochemistry is controlled are also discussed. This is an important aspect of pheromone production in Coleoptera, since slight changes in the stereochemistry can completely alter the activity of the molecule. © 1994 Wiley-Liss, Inc.

Fuzzy JK flip-flops as computational structures: design and implementation

Abstract: Current research on fuzzy set applications has yielded a better understanding of complex design problems involving nondeterministic human factors. This has in turn resulted in a significant number of efficient software case-study oriented realizations. Concurrently, efficient hardware implementations involving integration of a large number of discrete components have become feasible in light of existing technological achievements. Hirota and Ozawa (1989) introduced the notion of the fuzzy JK flip-flop, considering it an essential and basic component for effective processing of fuzzy information. Continuing with this line of reasoning, a discussion is presented of VLSI implementation issues with emphasis on design platforms to be used with the new structures. Next some comparisons are performed pertaining to the usefulness and realization of several logical connectives, followed by an examination of fuzzy sequential system design. The combinational part of the circuit is embodied in a single layer neural network in which weights are adjusted on the basis of training situations. Numerical considerations highlight the performance of the design process. >

Electromagnetic scattering by two parallel dielectric elliptic cylinders

Abstract: The transverse magnetic (TM) multiple scattering by two parallel homogeneous dielectric elliptic cylinders is investigated. The solution is an exact one and based on the separation of variables technique in conjunction with the addition theorem for Mathieu functions. It is expressed in terms of a system of simultaneous linear equations of infinite order which is then truncated for numerical computations. Representative numerical results with emphasis on the multiple scattering effects on the backscattering echo width are then generated, for some selected parameters, and presented. It is found that the multiple interactions between the two cylinders affect the echo width significantly. >

Begging the question as a pragmatic fallacy

Abstract: The aim of this paper is to make it clear how and why begging the question should be seen as a pragmatic fallacy which can only be properly evaluated in a context of dialogue. Included in the paper is a review of the contemporary literature on begging the question that shows the gradual emergence over the past twenty years or so of the dialectical conception of this fallacy. A second aim of the paper is to investigate a number of general problems raised by the pragmatic framework.

On restoring band-limited signals

Abstract: The problem of reconstruction of band-limited signals from discrete and noisy data is studied. The reconstruction schemes employing cardinal expansions are proposed and their asymptotical properties are examined. In particular, the conditions for the convergence of the mean integrated squared error are found and the rate of convergence is evaluated. The main difference between the proposed reconstruction scheme and the classical one is in treating the sampling rate and the reconstruction rate differently. This distinction is necessary to ensure consistency of the reconstruction scheme in the presence of noise

"Open" systems relaying

Abstract: This paper describes a development in relaying hardware and philosophy which has been made possible by DSPs and industrial grade PCs. Details are given of a prototype design capable of being assembled and configured by a utility and results of tests on this prototype using the RTDS at the Manitoba HVDC Research Centre are presented. The project is a joint effort between the University of Manitoba and Manitoba Hydro. >

Law and Providence in Joseph Bellamy's New England: The Origins of the New Divinity in Revolutionary America

Abstract: This study of religious thought and social life in early America focuses on the career of Joseph Bellamy (1719-1790), a Connecticut Calvinist minister noted chiefly for his role in originating the New Divinity-the influential theological movement that evolved from the writings of Bellamy's teacher, Jonathan Edwards. Tracing Bellamy's contributions as a preacher, noted controversialist, and church leader from the Great Awakening to the American Revolution, Mark Valeri explores why the New Divinity was so immensely popular. Set in social contexts such as the emergent market economy, the war against France, and the politics of rebellion, Valeri shows, Bellamy's story reveals much about the relationship between religion and public issues in colonial New England.

Gender-controlled measures of socially desirable responding

Abstract: Items in various scales that measure socially desirable responding (SDR) appear to vary in significance in male and female respondents. Recent findings suggest that females are more sensitive to the contents of more than two-thirds of such items. As a result, scales that measure SDR cannot be considered gender balanced, not to mention gender free. We examined three levels at which SDR items can be construed as gender controlled and arrived at a formula for item selection in the development of gender-controlled scales. Application of the formula resulted in the 10-item Gender-Free Inventory of Desirable Responding (GFIDR), with an inter-item reliability of .68, and the 12-item Gender Balanced Inventory of Desirable Responding (GBIDR), with an inter-item reliability of .71. The distribution characteristics of the two scales suggested that gender differences in the higher moments should be considered in the interpretation of results based on otherwise gender-controlled scales.

The well-ordered body: the quest for sanity through nineteenth-century asylum architecture.

Abstract: Nineteenth-century somatic theories of madness required specific types of treatment that focused on the body of the afflicted. This treatment stressed the primacy of caring for the body as a route to curing the mind. Treatment through environment would facilitate a transfer of the salubrious nature of a well-ordered place of treatment to the body and the mind of the lunatic. Therefore, the design of this environment became important as a method of treatment. The architect was to construct a facility ensuring the ordering, in detail, of placement, movement, and perception of the incarcerated. Also, this facility would act as a technology to facilitate the limits and types of bodily activities that would define a person as mad or sane. This article focuses on the architectural discourse of building for sanity.

Speech segmentation by variance fractal dimension

Abstract: This paper describes an implementation of the variance fractal dimension algorithm as a technique for the analysis of speech waveforms. The technique produces a fractal dimension trajectory which can be used for the detection of boundaries of an utterance in noise. The approach is superior to any other energy-based boundary-detection technique. It can also be used to segment speech utterances into sentences, words, or even phonemes. These observations are based on extensive experimental results on speech digitized at 44.1 kilosamples per second, with 16 bits in each sample. >

Cellular automata as an environment for simulating electromagnetic phenomena

Abstract: In this letter, the application of cellular automata to the modeling of electromagnetic phenomena is investigated. Cellular automata are fully discrete computational models (in space, time, and variables) and are exactly computable using digital hardware. One type of cellular automata, the HPP lattice gas automaton, is applied here to the modeling of two-dimensional electromagnetic field problems. Lattice gas automata can be completely described in terms of binary variables and are capable of providing linear wave behavior. Two examples are presented to explore the proposed approach: one-dimensional plane wave propagation and plane wave scattering from a perfectly conducting rectangular cylinder. >

Vertical Integration versus Vertical Separation: An Equilibrium Model

Abstract: In this paper, the role of strategic forces in vertical relationships is examined. Using a simple model of differentiated products with symmetric demands and costs, the Perfect equilibrium to a vertical integration-vertical separation game between manufacturers is determined. Given the assumptions of the model, I show that the manufacturer's decision whether to vertically integrate or to remain separate from its retailer depends on the degree of product differentiation. I show that when the products are poor substitutes, the only Perfect equilibrium is vertical integration by both manufacturers. As the products become closer substitutes, an additional Perfect equilibrium appears, both firms vertically separated. For manufacturers, the vertically separated equilibrium always Pareto dominates the vertical integration equilibrium when both equilibria exist.