Showing papers by "Carleton University published in 1995"

Computer self-efficacy: development of a measure and initial test

Abstract: This paper discusses the role of individuals' beliefs about their abilities to competently use computers (computer self-efficacy) in the determination of computer use. A survey of Canadian managers and professionals was conducted to develop and validate a measure of computer self-efficacy and to assess both its impacts and antecedents. Computer self- efficacy was found to exert a significant influence on individuals' expectations of the outcomes of using computers, their emotional reactions to computers (affect and anxiety), as well as their actual computer use. An individual's self-efficacy and outcome expecta- tions were found to be positively influenced by the encouragement of others in their work group, as well as others' use of computers. Thus, self-efficacy represents an important individual trait, which moderates organizational influences (such as encouragement and support) on an individual's decision to use computers. Understanding self-efficacy, then, is important to the successful implementation of systems in organizations. The existence of a reliable and valid measure of self-efficacy makes assessment possible and should have implications for organizational support, training, and implementation.

Application of Social Cognitive Theory to Training for Computer Skills

Abstract: While computer training is widely recognized as an essential contributor to the productive use of computers in organizations, very little research has focused on identifying the processes through which training operates, and the relative effectiveness of different methods for such training. This research examined the training process, and compared a behavior modeling training program, based on Social Cognitive Theory Bandura [Bandura, A. 1977. Self-efficacy: Toward a unifying theory of behavioral change. Psych. Rev.842 191--215; Bandura, A. 1978. Reflections on self-efficacy. Adv. Behavioral Res. Therapy1 237--269; Bandura, A. 1982. Self-efficacy mechanism in human agency. Amer. Psychologist372 122--147; Bandura, A. 1986. Social Foundations of Thought and Action. Prentice-Hall, Englewood Cliffs, NJ.], to a more traditional, lecture-based program. According to Social Cognitive Theory, watching others performing a behavior, in this case interacting with a computer system, influences the observers' perceptions of their own ability to perform the behavior, or self-efficacy, and the expected outcomes that they perceive, as well as providing strategies for effective performance. The findings provide only partial support for the research model. Self-efficacy exerted a strong influence on performance in both models. In addition, behavior modeling was found to be more effective than the traditional method for training in Lotus 1-2-3, resulting in higher self-efficacy and higher performance. For WordPerfect, however, modeling did not significantly influence performance. This finding was unexpected, and several possible explanations are explored in the discussion. Of particular surprise were the negative relationships found between outcome expectations and performance. Outcome expectations were expected to positively influence performance, but the results indicated a strong negative effect. Measurement limitations are presented as the most plausible explanation for this result, but further research is necessary to provide conclusive explanations.

First measurement of the rate for the inclusive radiative penguin decay b→sγ

Abstract: We have measured the inclusive {ital b}{r_arrow}{ital s}{gamma} branching ratio to be (2.32{plus_minus}0.57{plus_minus}0.35){times}10{sup {minus}4}, where the first error is statistical and the second is systematic. Upper and lower limits on the branching ratio, each at 95% C.L., are {ital B}({ital b}{r_arrow}{ital s}{gamma}){lt}4.2{times}10{sup {minus}4} and {ital B}({ital b}{r_arrow}{ital s}{gamma}){gt}1.0{times}10{sup {minus}4}. These limits restrict the parameters of extensions of the standard model.

The Method of Layers

Abstract: Distributed applications are being developed that contain one or more layers of software servers. Software processes within such systems suffer contention delays both for shared hardware and at the software servers. The responsiveness of these systems is affected by the software design, the threading level and number of instances of software processes, and the allocation of processes to processors. The Method of Layers (MOL) is proposed to provide performance estimates for such systems. The MOL uses the mean value analysis (MVA) linearizer algorithm as a subprogram to assist in predicting model performance measures. >

Individual Differences in 4-Year-Old Children's Acquisition of Vocabulary during Storybook Reading.

Abstract: Two experiments were conducted to assess how children who differ in vocabulary knowledge learn new vocabulary incidentally from listening to stories read aloud. In both experiments, 4-year-old children were classified as having either high or low word knowledge on the basis of a median split of their Peabody Picture Vocabulary Test-Revised (PPVT-R) standard scores. In Experiment 1, children either listened passively or labeled pictures using novel words during the book readings. We found that children with larger vocabularies produced more novel words than did children with smaller vocabularies, and children who answered questions during the book readings comprehended and produced more words than did children who passively listened to the story. In Experiment 2, children either listened to readings of a book, pointed to pictures during the readings, or labeled pictures during the readings. Children with larger vocabularies comprehended more novel words than did children with smaller vocabularies. Children who actively participated by labeling or pointing learned more words than did children who listened passively to book readings. The findings clarify the role of active responding by demonstrating that verbal and nonverbal responding are effective means of enhancing vocabulary acquisition

Analysis of interconnect networks using complex frequency hopping (CFH)

Abstract: With increasing miniaturization and operating speeds, loss of signal integrity due to physical interconnects represents a major performance limiting factor of chip-, board- or system-level design. Moment-matching techniques using Pade approximations have recently been applied to simulating modelled interconnect networks that include lossy coupled transmission lines and nonlinear terminations, giving a marked increase in efficiency over traditional simulation techniques. Nevertheless, moment-matching can be inaccurate in high-speed circuits due to critical properties of Pade approximations. Further, moment-generation for transmission line networks can be shown to have increasing numerical truncation error with higher order moments. These inaccuracies are reflected in both the frequency and transient response and there is no criterion for determining the limits of the error. In this paper, a multipoint moment-matching, or complex frequency hopping (CFH) technique is introduced which extracts accurate dominant poles of a linear subnetwork up to any predefined maximum frequency. The method generates a single transfer function for a large linear subnetwork and provides for a CPU/accuracy tradeoff. A new algorithm is also introduced for generating higher-order moments for transmission lines without incurring increasing truncation error. Several interconnect examples are considered which demonstrate the accuracy and efficiency in both the time and frequency domains of the new method. >

The stochastic rendezvous network model for performance of synchronous client-server-like distributed software

Abstract: Distributed or parallel software with synchronous communication via rendezvous is found in client-server systems and in proposed open distributed systems, in implementation environments such as Ada, V, remote procedure call systems, in transputer systems, and in specification techniques such as CSP, CCS and LOTOS The delays induced by rendezvous can cause serious performance problems, which are not easy to estimate using conventional models which focus on hardware contention, or on a restricted view of the parallelism which ignores implementation constraints Stochastic rendezvous networks are queueing networks of a new type which have been proposed as a modelling framework for these systems They incorporate the two key phenomena of included service and a second phase of service This paper extends the model to also incorporate different services or entries associated with each task Approximations to arrival-instant probabilities are employed with a mean-value analysis framework, to give approximate performance estimates The method has been applied to moderately large industrial software systems >

A neural network modeling approach to circuit optimization and statistical design

Abstract: The trend of using accurate models such as physics-based FET models, coupled with the demand for yield optimization results in a computationally challenging task. This paper presents a new approach to microwave circuit optimization and statistical design featuring neural network models at either device or circuit levels. At the device level, the neural network represents a physics-oriented FET model yet without the need to solve device physics equations repeatedly during optimization. At the circuit level, the neural network speeds up optimization by replacing repeated circuit simulations. This method is faster than direct optimization of original device and circuit models. Compared to existing polynomial or table look-up models used in analysis and optimization, the proposed approach has the capability to handle high-dimensional and highly nonlinear problems. >

Use Case Maps for Object-Oriented Systems

Abstract: Object-oriented and real time together the behavioural fabric of systems a context for designing with use case maps a simple example basic use case map model case study - a conventional object-oriented application advanced use case map model case study - high level design of a real-time, distributed system detailed design notation case study - rounding out the real-time, distributed system example macro and micro patterns supplementing familiar design methods. Appendix: notation summary some coding examples.

Body image and steroid use in male bodybuilders.

Abstract: This study was designed to examine the association between body image and eating-related attitudes among male bodybuilders in relation to two athletic comparison groups, runners and martial artists. It was also of interest to examine whether steroid use may be associated with body image disturbances in athletes. The volunteer sample of 139 male athletes recruited from fitness centers comprised 43 bodybuilders, 48 runners, and 48 martial artists (tae kwon do practitioners). Standardized measures of body dissatisfaction, drive for thinness, drive for bulk, bulimia, self-esteem, depression, maturity fears, and perfectionism as well as questionnaires designed to measure attitudes toward steroids, and rates of steroid use were administered in a manner that encouraged disclosure. Bodybuilders reported significantly greater body dissatisfaction, with a high drive for bulk, high drive for thinness, and increased bulimic tendencies than either of the other athletic groups. In addition bodybuilders reported significant elevations on measures of perfectionism, ineffectiveness, and lower self-esteem. They also reported the greatest use of anabolic steroids and most liberal attitudes towards using steroids. Steroid users reported that the most significant reason for using steroids was to improve looks. Steroid users reported an elevated drive to put on muscle mass in the form of bulk, greater maturity fears, and enhanced bulimic tendencies than nonusers. The results suggest that male bodybuilders are at risk for body image disturbance and the associated psychological characteristics that have been commonly reported among eating disorder patients. These psychological characteristics also appear to predict steroid use in this group of males.

Time division multiple access methods for wireless personal communications

Abstract: Time division multiple access (TDMA) is a classic approach to multiple access in digital cellular wireless communications systems. The authors summarize a number of frequency and time slot allocation techniques for enhancing the capacity and flexibility of TDMA-based systems. They also describe how the problems of fading, delay spread, time variability and interference affect TDMA systems, and how they may he countered and even exploited by appropriate techniques of detection, diversity, coding, adaptive equalization and slow frequency hopping (FH). It is worth emphasizing that the use of one of these techniques, slow random FH, results in a system that is in effect a hybrid of TDMA and code division multiple access (CDMA). >

Gender, Structural Factors, and Credit Terms between Canadian Small Businesses and Financial Institutions

Abstract: This paper reports on an analysis of whether or not the terms of bank credit differ between men and women business owners. Based on a large sample of borrowing experiences, it is found that men and...

Homology and phylogenetic implications of male genitalia in Diptera - Eremoneura

Abstract: Homologies of male genitalic structures in the Eremoneura (Empidoidea + Cyclorrhapha) are examined and implications for the phylogenetic relationships of the included families are discussed in light of other characters. A revised epandrial hypothesis for the evolution of male genitalia within the Eremoneura is presented, based on comparison of male genitalic features throughout the Brachycera, and a periandrial hypothesis is rejected. Ground plan modifications of the genitalia of Eremoneura include complete sclerotization of the subepandrial membrane along its length to form a subepandrial sclerite, formation of bacilliform sclerites, loss of the lateral ejaculatory processes of the sperm pump, development of a deeply emarginate epandrium, and fusion of the hypandrium with the gonocoxites. Ground plan apomorphies of the Cyclorrhapha, including Opetiidae, consist of a sperm pump separated from the base of the phallus, circumversion of the genitalia, loss of the gonocoxal apodemes, and development of surstyli. The ground plan of the Empidoidea is characterized by the apomorphic loss of gonostyli, and the development of a sperm pump with a lever-like ejaculatory apodeme. Surstyli have developed independently in several lineages of Empidoidea, parallel to their development in Cyclorrhapha, as have losses of the gonocoxal apodemes. The above characters support the monophyly of the Eremoneura and also indicate that the Empidoidea and Cyclorrhapha are sister groups, as opposed to alternative hypotheses that suggest the Empidoidea is paraphyletic with respect to the Cyclorrhapha. The monophyly of Cyclorrhapha, exclusive of Opetiidae, is supported by the presence of a phallapodeme. The Lonchopteridae and Phoroidea are united partially on the basis of a similar reduction of pregenital sclerites in the male. The Phoroidea is characterized by the apomorphic loss of gonostyli and abdominal spiracle 7 in the male. The Syrphoidea and Schizophora are hypothesized to share a synapomorphic lever-like phallapodeme. The Syrphoidea is characterized by a right-side deflexion of the hypopygium, whereas the Schizophora possess gonostyli that are adducted against the hypandrium, and circumversion that is completed entirely within the puparium.

Modeling and simulation of self-similar variable bit rate compressed video: a unified approach

Abstract: Variable bit rate (VBR) compressed video is expected to become one of the major loading factors in high-speed packet networks such as ATM-based B-ISDN. However, recent measurements based on long empirical traces (complete movies) revealed that VBR video traffic possesses self-similar (or fractal) characteristics, meaning that the dependence in the traffic stream lasts much longer than traditional models can capture.In this paper, we present a unified approach which, in addition to accurately modeling the marginal distribution of empirical video records, also models directly both the short and the long-term empirical autocorrelation structures. We also present simulation results using synthetic data and compare with results based on empirical video traces.Furthermore, we extend the application of efficient estimation techniques based on importance sampling that we had used before only for simple fractal processes. We use importance sampling techniques to efficiently estimate low probabilities of packet losses that occur when a multiplexer is fed with synthetic traffic from our self-similar VBR video model.

Robust Estimation of Mean Squared Error of Small Area Estimators

Abstract: A well-known model, due to Fay and Herriot, for estimating small area (domain) means, μ i , is considered. Given μ i 's, it is assumed that the survey estimators, y i , are independent with means μ i and known variances Di, i = 1, …, t. Further, the μ i 's are assumed to be independent with means x′iβ and unknown variance A, where x i is a vector of benchmark variables related to μ i and β is a vector of regression parameters. An empirical best linear unbiased prediction (EBLUP) estimator or an empirical linear Bayes estimator, t i (Â, y), of μ i is obtained. It is shown that an estimator of mean squared error (MSE) of t t (Â, y), derived by Prasad and Rao under normality of μ i and y i given μ i , is robust with respect to nonnormality of the μ i 's. Specifically, it is shown that the Prasad–Rao estimator of MSE is correct to terms of order O(t −1) for large t, assuming only certain moment conditions on the μ i 's and normally distributed survey errors. Results of a simulation study on the accur...

Extra-pair paternity and the opportunity for sexual selection in a socially monogamous bird (Dendroica petechia)

Abstract: We used multi-locus DNA fingerprinting to characterise the genetic mating system of the socially monogamous yellow warbler (Dendroica petechia). Over 2 years there were no instances of brood parasitism, but 59% of families (n = 90) contained extrapair sired young and 37% of offspring (n = 355) were of extra-pair paternity. Most hypotheses for extra-pair mating in monogamous species assume a paternity benefit to extra-pair sires, and focus on the benefit(s) to females. However, the assumption of male benefit has been little tested. Among yellow warblers, known extra-pair sires were just as likely to be cuckolded as any male in the population, and there was at least one reciprocal exchange of extra-pair paternity. Nevertheless, among known extra-pair sires, the paternity gains from extra-pair paternity were, on average, greater than the losses in their own families. These results show there is a paternity benefit to certain males. However, the benefit is not absolute but relative and therefore more difficult to measure. The results also suggest that patterns of extra-pair fertilisation are not determined by female choice alone. Most confirmed extra-pair mates were territorial neighbours, but some resided as far as three territories apart, and greater spatial separation was implied in other cases. Thus, the opportunity for extra-pair mating is great. We estimate that as a result of extra-pair fertilisations, variance in male mating success is increased somewhere between 3-fold and 15-fold over that which would result from within-pair reproduction alone. These findings affirm the potential importance of extra-pair reproduction for sexual selection in monogamous species and they support earlier suggestions that extra-territorial forays by male yellow warblers are for the purpose of extra-pair mating.

Westernizing the Third World: The Eurocentricity of Economic Development Theories

Abstract: The second edition of this successful and popular text has been updated and revised to include recent issues in development economics. Significant new additions include: * Asian values and development * democracy, human rights and good governance * globalization and development * boxed summaries of key arguments and glossary. Westernizing the Third World identifies the mainstream economic theories which have been employed in developing countries. The author examines these and explains why Eurocentric concepts are not suitable for the developing world.

The Troubling Aspects of a Building Block Hypothesis for Genetic Programming

Abstract: In this paper we carefully formulate a Schema Theorem for Genetic Programming (GP) using a schema definition that accounts for the variable length and the non-homologous nature of GP's representation. In a manner similar to early GA research, we use interpretations of our GP Schema Theorem to obtain a GP Building Block definition and to state a “classical” Building Block Hypothesis (BBH): that GP searches by hierarchically combining building blocks. We report that this approach is not convincing for several reasons: it is difficult to find support for the promotion and combination of building blocks solely by rigourous interpretation of a GP Schema Theorem; even if there were such support for a BBH, it is empirically questionable whether building blocks always exist because partial solutions of consistently above average fitness and resilience to disruption are not assured; also, a BBH constitutes a narrow and imprecise account of GP search behavior.

How Do Real Roots Work? (Some New Views of Root Structure).

Abstract: Root systems of plants growing in the field are marvelously successful at foraging for nutrients and water in a hostile, competitive environment where supplies of them are very limited, local, and variable. This success is not surprising because this is the environment in which they have evolved. We are uncovering increasing complexities of this life of roots in the soil, such as their interactions with a broad range of microbes well beyond the better-known relationships with mycorrhizal fungi and root-nodule bacteria. More is being discovered about the two-way interchange of materials and messages across the root-soil interface. Growth movements, the groping for nutrients and water, have intrigued plant biologists since they were so well described by Darwin, and they continue to be puzzles that become more complex as they are better understood. Additionally, the variety and success of responses of roots to environmental stresses multiply and raise more puzzling questions. Useful background material concerning these topics is available in Waisel et al. (1991). Despite these advances, the model of root structure used to interpret root system function is inadequate. This model is too often the stylized, simplistic, textbook interpretation of old studies of seedling roots of a very few species and is derived from roots and shoots still living heterotrophically on reserves, transpiring little or not at all. Also, these roots have never met the rigors of the field soil. Furthermore, traditional anatomical study has focused on the apical meristem and the patterns of the young tissues within a few millimeters of the tip, rarely beyond a few centimeters. One laboratory manual, a standard reference for almost 30 years, includes a table of the distances from the root tip at which major developmental events occur in seven different species. The farthest distance indicated is 8.3 cm in a woody plant. For the herbaceous species, the last developmental event is even closer to the tip. Corn xylem lignification is listed at less than 1.7 cm. The limitations of such a view can be calculated from Dittmer's (1937) famous data for total lengths of roots (main and three orders of branches) of a single soil-grown rye plant. The first 10 cm of all 143 main roots total about one millionth of the whole root length. In 1980, together with a brave graduate student named Janet Vermeer, I began to study the roots of corn plants in the field. We started by washing the roots to get rid of as much of the "dirt" as possible, so worrying to an electron microscopist. But a freshly excavated plant, unwashed as shown in Figure 1A, impressed us with the heterogeneity in size, origin, and soil binding, which have intrigued me and my students ever since. This interest has led us to explore the structure and functioning of root systems growing in the field. The results have been replete with surprises. In this paper I will include some of these surprises and the work of other groups, which provide new insights into three aspects of root structure and function, with important implications for many root-related studies: (a) delayed development of xylem, (b) the development of the interface with the soil, and (c) branch roots and their role.

Body image as a leisure constraint: Examining the experience of aerobic exercise classes for young women

Abstract: Previous research has shown that women, and especially young women, in this culture experience pressure to be thin. Although considerable research has been directed toward the investigation of body image and its relationship to psychological health and self‐image, the impact of body image on leisure behavior has not been adequately addressed, nor has body image received much attention as a potential leisure constraint. The purpose of this study was to investigate ways in which body image might function as a constraint to young women's participation in aerobic exercise classes. The study used both quantitative and qualitative methods, including a survey of 190 women undergraduate students and in‐depth interviews with a sub‐sample of 11 students. The qualitative data are the main focus of this analysis. The data indicated that body image did not seem to prevent participation or constrain levels of participation in aerobics. Nevertheless, body image concerns were shown to constrain the enjoyment of ...

Antioxidant defenses and metabolic depression in a pulmonate land snail

Abstract: During arousal from estivation oxygen consumption by land snails (Otala lactea) increases severalfold. To determine whether snails prepared for an accompanying rise in the rates of oxyradical generation by altering their antioxidant defense mechanisms, changes in the activities of antioxidant enzymes and lipid peroxidation products were quantified in foot and hepatopancreas of control, 30-day estivating, and aroused snails. Compared with controls, estivating O. lactea showed significant increases in the activities of foot muscle superoxide dismutase (SOD) (increasing by 56-67%), catalase (51-72%), and glutathione S-transferase (79-108%), whereas, in hepatopancreas, SOD (57-78%) and glutathione peroxidase (93-144%) increased. Within 40 min after arousal began, hepatopancreas glutathione peroxidase activity had returned to control values, but SOD showed a further 70% increase in activity but then returned to control levels by 80 min. Estivation had no effect on total glutathione (GSH + 2 GSSG) concentrations in tissues, but GSSG content had increased about twofold in both organs of 30-day dormant snails. Lipid peoxidation (quantified as thiobarbituric acid reactive substances) was significantly enhanced at the onset of arousal from dormancy, indicating that oxidative stress and tissue damage occurred at this time. The data suggest that antioxidant defenses in snail organs are increased while snails are in the hypometabolic state as a preparation for oxidative stress during arousal.