Showing papers by "Ryerson University published in 2001"

The Immigration Dilemma: The Role of Perceived Group Competition, Ethnic Prejudice, and National Identity

Abstract: In this article, we discuss the role of perceived competition for resources in determining negative attitudes toward immigrants and immigration in North America. We first provide background information on immigration policies and levels of immigration to Canada and the United States. Following an overview of our theoretical perspective, we then describe the research we have conducted in Canada and the United States indicating that perceived zero-sum competition between groups, whether situationally induced or a function of chronic belief in zero-sum relations among groups, is strongly implicated in negative immigration attitudes. In addition, we describe our recent attempts to improve attitudes toward immigrants and immigration through the targeting of zero-sum beliefs and through manipulations of the inclusiveness of national identity.

Safety Effect of Roundabout Conversions in the United States: Empirical Bayes Observational Before-After Study

Abstract: Modern roundabouts are designed to control traffic flow at intersections without the use of stop signs or traffic signals. U.S. experience with modern roundabouts is rather limited to date, but in recent years there has been growing interest in their potential benefits and a relatively large increase in roundabout construction. This interest has created a need for data regarding the safety effect of roundabouts. Changes in motor vehicle crashes following conversion of 23 intersections from stop sign and traffic signal control to modern roundabouts are evaluated. The settings, located in seven states, are a mix of urban, suburban, and rural environments with the urban sample consisting of both single-lane and multilane designs and the rural sample consisting of only single-lane designs. A before-after study was conducted using the empirical Bayes procedure, which accounts for regression to the mean and traffic volume changes that usually accompany conversion of intersections to roundabouts. For the 23 inte...

Current and electromagnetic field associated with lightning-return strokes to tall towers

Abstract: An analysis of electric and magnetic fields radiated by lightning first and subsequent return strokes to tall towers is presented. The contributions of the various components of the fields, namely, static, induction, and radiation for the electric field, and induction and radiation for the magnetic field are illustrated and discussed. It is shown in particular that the presence of a tower tends, in general, to increase substantially the electric and magnetic field peaks and their derivatives. This increase is mainly caused by the presence of two oppositely propagating current wavefronts originating from the tower top and by the very high propagation velocity of current pulses within the tower, and depends essentially on the wavefront steepness of the channel-base current. Because of the last factor, the increase of the field magnitudes is found to be significantly higher for subsequent return strokes, which are characterized by much faster risetimes compared to first return strokes. The presented results are consistent with experimental observations of current in lightning strokes to the Toronto CN Tower and of the associated electric and magnetic fields measured 2 km away. These findings partially explain the fact that subsequent return strokes characterized by lower current peaks but higher front steepnesses and return stroke speeds may result in higher field peaks. The results obtained have important implications in electromagnetic (EM) compatibility. It is found that lightning strokes to tall metallic objects lead to increased EM field disturbances. Also, subsequent return strokes are to be considered an even more important source of EM interference than first return strokes. Indeed, EM fields from subsequent strokes are characterized by faster fronts and additionally, they may reach greater peaks than first strokes. Lastly, findings of this study emphasize the difficulty of extracting reliable lightning return stroke current information from remote EM field measurements using oversimplified formulae.

Toronto’s Image As a Destination: A Comparative Importance-Satisfaction Analysis by Origin of Visitor

Abstract: The purposes of this study were to examine Toronto visitors’ perceptions of products and services in terms of importance and satisfaction by visitor origin and to apply the results to the importance-satisfaction model to identify strengths in service. The sample consisted of 359 visitors to Toronto in either August or November 1998. The results suggest that, in general, the overall visitors’ image of Toronto is similar. Closer analysis of the visitors’ country of origin, however, shows that there are some important differences in the attributes seen as important as well as in levels of satisfaction.

Coalition analysis in group decision support

Abstract: GMCR II, a decision support system based on the Graph Model for Conflict Resolution, now contains an algorithm for Coalition Analysis to alert users that certain decision-makers would find it both feasible and beneficial to co-ordinate their actions The theory and implementation of Coalition Analysis in GMCR II are discussed and illustrated

Theory of software reliability based on components

Abstract: We present a foundational theory of software system reliability based on components. The theory describes how component developers can design and test their components to produce measurements that are later used by system designers to calculate composite system reliability — without implementation and test of the system being designed. The theory describes how to make component measurements that are independent of operational profiles, and how to incorporate the overall system-level operational profile into the system reliability calculations. In principle, the theory resolves the central problem of assessing a component, which is: a component developer cannot know how the component will be used and so cannot certify it for an arbitrary use; but if the component buyer must certify each component before using it, component-based development loses much of its appeal. This dilemma is resolved if the component developer does the certification and provides the results in such a way that the component buyer can factor in the usage information later, without repeating the certification. Our theory addresses the basic technical problems inherent in certifying components to be released for later use in an arbitrary system.Most component research has been directed at functional specification of software components; our theory addresses the other, equally important, side of the coin: component quality.

PEBBLES: A Personal Technology for Meeting Educational, Social and Emotional Needs of Hospitalised Children

Abstract: Wayne Gretzky’s PEBBLES TM (Providing Education By Bringing Learning Environments to Students) is a unique example of a personal technology, one in which PC-based video-conferencing is used to make a real-time link between a hospitalised child and his or her regular classroom. The system provides an opportunity for children who are in isolated situations, such as hospitals, to maintain a meaningful link with their regular educational and social environments, thereby minimising many of the secondary problems that may develop as a result of long-term illness and hospitalisation. The objective of this paper is to illustrate the impact that PEBBLES had on one child who directly benefited from the system and on the people with whom she interacted (classmates, parents, teachers and hospital staff). These results were used to explore how exposure to this personal technology influenced the behaviours and attitudes of those involved in this study. The results indicate that, overall, PEBBLES has a very positive effect on both the young and adult participants; the most dramatic effect of all was on the ill child who used PEBBLES to attend school.

Immigrant nurses' experience of racism.

Abstract: Purpose: To document and describe the experiences of immigrant nurses of colour who have filed grievances concerning their employers' discriminatory practices; and to solicit their views of existing policies and recommendations for equity in professional life. Design and Methods: In this descriptive, exploratory study nine immigrant nurses of colour in Ontario, Canada, were interviewed between 1997 and 1998. Data were collected through face-to-face interviews and in focus groups. The discourse theory and methods of van Dijk and Essed were used to analyse the qualitative data. Findings: Recurring themes were: (a) being marginalized and acknowledging and naming the racist experiences; (b) experiencing physical stress and emotional pain; (c) strategizing to cope and survive; (d) recommending policy changes. Conclusions: All nurses interviewed had experienced reprisals as a result of complaining or filing grievances and unfairness was encountered in the redress process itself. Participants recommended policy initiatives to ensure equity and fair practices in the nursing profession.

Pricing vulnerable European options when the option’s payoff can increase the risk of financial distress

Abstract: We extend the results of Johnson and Stulz (Johnson, H., Stulz, R., 1987. Journal of Finance 42, 267–280) and Klein (Klein, P.C., 1996. Journal of Banking and Finance 20, 1211–1229) for valuing European options subject to the risk of financial distress on the part of the option writer. Our model incorporates a default boundary which depends on the potential liability of the written option as in Johnson and Stulz (1987), and also on the option writer’s other liabilities as in Klein (1996). As in both of these papers, the pay-out ratio in the event of financial distress is linked to the assets of the option writer, and the correlation between the assets of the option writer and the asset underlying the option is explicitly modeled. Although no analytical solution is available, we illustrate the importance of this approach through examples, which are evaluated numerically. We also develop an approximate analytical solution, which works well in most situations.

Implicit Claims: The Role of Corporate Reputation in Value Creation

Abstract: This paper draws on an economic/strategy perspective to address the relationship between corporate reputation and shareholder value We argue that in selling a product or service or purchasing inputs, companies issue both explicit and implicit claims The former refers to the contractual basis on which goods and services are sold or purchased by companies whereas the latter relates to company promises to stakeholders (employees, customers, suppliers, etc) that are either too vague or too costly to specify in writing Implicit claims reflect promises of quality, good working conditions, and service levels which are not explicitly stated in any contracts, but which, when present, permit a company to sell products and/or services at higher prices, and purchase goods and services from suppliers at lower prices than competitors Implicit claims are not sold separately from the product, cannot be traded on a market, and hence have no legal standing However, implicit claims do have economic value, and that value is reflected in the company's share price Implicit claims have a value only if stakeholders believe that the company will honor them It is in this context that reputation generates value to firms By expending resources to fulfil implicit claims, a company can establish trust with its stakeholders that it will honor the implicit claims and hence confirm their value to stakeholders Reputation is built by incurring expenditures in fulfilling promises of implicit claims and by signaling that future implicit claims will be honored Corporate reputations affect a firm's ability to issue valuable implicit claims By viewing reputation through the implicit claims perspective, management is presented with a framework that permits identification of the link between implicit claims, reputation, and shareholder value Decisions can be made on the extent of investments to generate reputation and the responses to reputational threats The next section describes the explicit and implicit claim scenario in more depth and relates it to academic literature Section three demonstrates that conventional reputation literature describes reputation in terms of stakeholders' perceptions and that this analysis confounds implicit and explicit claims Section four argues that the reputation impact on shareholder value is best viewed through the implicit claims perspective By understanding the importance of implicit claims and the costs of building and maintaining reputation that facilitates issuance of these claims, managers can make informed decisions on reputation creation and maintenance The last section discusses the implications of implicit claims for managing corporate reputation

A space vector modulated CSI-based AC drive for multimotor applications

Abstract: A space vector controlled channel state information (CSI) drive for multimotor applications is investigated The multimotor operation of the drive is achieved by integrating the proposed active damping control, inverter-side DC link voltage feedforward control and pulse width modulation (PWM) index control into the conventional V/f control The main function of the active damping control is to suppress possible LC resonances caused by the inverter filter capacitor and motor inductances This function is essential in achieving stable operation of the drive, especially in the multimotor drive where multiple LC resonant modes exist An additional advantage provided by the active damping control is that it makes the control system less sensitive to motor parameters The inverter-side DC link voltage feedforward control and the adjustable PWM modulation index control are developed to improve the dynamic performance of the drive system In addition, the proposed space vector PWM pattern features a low switching frequency (500 Hz), which makes the proposed drive system suitable for high power applications The system stability is investigated by means of eigenvalue analysis The theoretic analysis is verified by experiments on a digital signal processing (DSP) controlled CSI multimotor drive

Coupling the use of computer chemical speciation models and culture techniques in laboratory investigations of trace metal toxicity

Abstract: The bioavailability and toxicity of a dissolved metal are closely linked to the metal’s chemical speciation in solution. A variety of inorganic and organic ligands are often used in laboratory toxicity tests to control the concentration of labile trace metal in solution. Computerised chemical speciation models based on thermodynamic principles can be used to estimate metal speciation under such experimental conditions. However, these models are sensitive to the quality of their thermodynamic databases. Detailed protocols for the incorporation of reliable equilibrium formation constants into widely available computer chemical speciation programs (e.g., MINEQL+ and MINTEQ) are provided. The examples demonstrate both the benefits and the potential pitfalls involved in the use of chemical speciation models. The application of chemical speciation modelling to metal toxicity studies is discussed and guidelines are proposed for its proper use. Both defined media and chemical speciation programs have co-e...

Breakdown-Related Capacity for Freeway with Ramp Metering:

Abstract: Research was conducted to better understand the breakdown phenomenon and look for ways of strategically increasing capacity and travel speed by reducing breakdowns on a section of freeway in Mississauga, Ontario, that is subject to ramp metering. The major task was to quantify the probability of breakdown as an increasing function of volume at the critical location. Data from 71 peak periods during which breakdown occurred at the critical merge were used to estimate the function, which was then used in a computer simulation of fixed- and variable-rate metering to demonstrate the potential benefits of using the probability-of-breakdown concept as a basis for ramp metering. The results indicate, for example, that variable-rate metering that complements a constant merge flow limit of 2,320 veh/h per lane could increase peak-hour throughput from about 6,460 to 6,600 veh/h at this location. They also indicate that 2,500 veh/h might be allowed, provided stringent metering for quick recovery to free flow is feasible.

Photocatalytic degradation of aqueous organic solvents in the presence of hydroxyl radical scavengers

Abstract: Tetrahydrofuran (THF) and 1,4-dioxane (DIOX) are two common solvents that are found in contaminated groundwater. Photocatalytic degradation of these two organic solvents in water was studied in the presence of carbonate and bicarbonate, which are hydroxyl radical scavengers. The reactions were performed in an annular slurry photoreactor. It was found that bicarbonate and carbonate ions acted as hydroxyl radical scavengers and slowed down the DIOX degradation rate but did not significantly affect the THF degradation rate. The slight enhancement in the THF degradation rate in the presence of sodium bicarbonate may be due to the increase in pH. In addition, it appears that bicarbonate and carbonate ions were reduced to other organic species during the photocatalytic reaction.

Adaptive Image Processing: A Computational Intelligence Perspective

Abstract: From the Publisher: Adaptive image processing is one of the most important techniques in visual information processing, especially in image restoration, filtering, enhancement, and segmentation. While other books present some aspects of this important issue, none treat it from a purely computational intelligence (CI) point of view. The first to do so and using the synergies of neural networks, fuzzy logic, and evolutionary computation, Adaptive Image Processing covers both the fundamentals of CI and human perception and the CI methods and algorithms for adaptive image processing in regularization, edge detection, enhancement, and early vision.

Modeling heart rate variability in healthy humans: a turbulence analogy.

Abstract: Many complex systems share similar statistical characteristics. In this Letter, a turbulence analogy is proposed for the long-term heart rate variability of healthy humans. Based on such an analogy, the equivalence of an inertial range is found and a cascade model, which captures the statistical properties of the heart rate data, is given.