Showing papers by "Ryerson University published in 1999"

Numerical distribution functions of likelihood ratio tests for cointegration

Abstract: This paper employs response surface regressions based on simulation experiments to calculate asymptotic distribution functions for the Johansen-type likelihood ratio tests for cointegration. These are carried out in the context of the models recently proposed by Pesaran, Shin, and Smith (1997) that allow for the possibility of exogenous variables integrated of order one. The paper calculates critical values that are very much more accurate than those available previously. The principal contributions of the paper are a set of data files that contain estimated asymptotic quantiles obtained from response surface estimation and a computer program for utilizing them. This program, which is freely available via the Internet, can be used to calculate both asymptotic critical values and P-values. Copyright © 1999 John Wiley & Sons, Ltd.

Ultrasound imaging of apoptosis: high-resolution non-invasive monitoring of programmed cell death in vitro, in situ and in vivo.

Abstract: A new non-invasive method for monitoring apoptosis has been developed using high frequency (40 MHz) ultrasound imaging. Conventional ultrasound backscatter imaging techniques were used to observe apoptosis occurring in response to anticancer agents in cells in vitro, in tissues ex vivo and in live animals. The mechanism behind this ultrasonic detection was identified experimentally to be the subcellular nuclear changes, condensation followed by fragmentation, that cells undergo during apoptosis. These changes dramatically increase the high frequency ultrasound scattering efficiency of apoptotic cells over normal cells (25- to 50-fold change in intensity). The result is that areas of tissue undergoing apoptosis become much brighter in comparison to surrounding viable tissues. The results provide a framework for the possibility of using high frequency ultrasound imaging in the future to non-invasively monitor the effects of chemotherapeutic agents and other anticancer treatments in experimental animal systems and in patients.

Empirical Bayes Procedure for Ranking Sites for Safety Investigation by Potential for Safety Improvement

Abstract: The identification of sites requiring investigation for possible safety treatment is one of the most important aspects of infrastructure safety management and has been the subject of considerable research aimed at improving the efficiency of the process. The more recent techniques use the empirical Bayes (EB) method for estimating the safety of specific sites. A refinement of the EB method that is conceptually sound and inherently simple to apply is the focus of this research. With this refinement, the EB estimate of the safety of a site is compared with its expected safety to determine the potential for safety improvement, which forms the basis for ranking sites for safety investigation. A comparative evaluation is provided of the proposed method against other EB methods and the more conventional ones, with data for signalized intersections and two-lane rural highway sections. The refined EB method is shown to be comparatively efficient.

Exergy analysis of waste emissions

Abstract: Recently, significant attention has been directed towards the use of exergy analysis in the assessment of thermal and other industrial processes and their environmental impacts since exergy analysis is an effective tool both for achieving efficient energy utilization with minimum (or zero) environmental impact and for understanding environmental issues In this study, the concepts of exergy analysis and the linkages between exergy and environmental impact are discussed, and several issues regarding the exergies of waste emissions are addressed Exergy is a measure of the degree of disequilibrium between a substance and its environment The relations between several measures of environmental impact potential and exergy are investigated by comparing current methods used to assess the environmental impact potential of waste emissions and the exergy associated with those emissions A case study is presented, to highlight the information revealed using exergy, in which the measures of environmental impact potential considered are the Ontario Ministry of Environment's schedule of industrial air emission limits, and two methods of assessing the environmental costs for air emissions resulting from the combustion of three common fossil fuels: coal, oil and natural gas Copyright © 1999 John Wiley & Sons, Ltd

Second‐law analysis: approaches and implications

Abstract: A comparison is presented of the main approaches to second-law analysis (SLA) reported in the literature. Five SLAs are considered: exergy, physical-exergy, exergy-consumption, negentropy and entropy analyses. The application of the SLAs is illustrated through an example. In addition, several significant implications of SLA are examined in the fields of environmental impact and economics. The presentation herein of the approaches to and implications of SLA is expected to enhance understanding of SLA and improve its usefulness. Copyright © 1999 John Wiley & Sons, Ltd.

An Intergroup Perspective on Religion and Prejudice

Abstract: Based on the reasoning that religious groups evidence intergroup processes that can create prejudice, two studies examined the relation between religiosity and attitudes toward religious and non-religious others. In both studies, among more religious individuals, attitudes toward religious others were very positive and attitudes toward non-religious others were quite negative. These relations emerged on all measures of traditional religiosity used. Some prejudice against religious others existed among less religious individuals, but it was less pronounced and less pervasive than the prejudice of more religious people. It is suggested that intergroup processes such as competition between religious groups for resources or value promotion likely foster prejudice against religious outgroup members, perhaps irrespective of personal religious orientation.

Power loss and junction temperature analysis of power semiconductor devices

Abstract: A newly developed electrothermal calculation method is implemented to estimate the power loss and working temperature of insulated gate bipolar transistor (IGBT) devices. Based on the measurement of the IGBT's characteristics, the exact estimation of power loss considering the junction temperature is introduced. Then, the thermal network is used to calculate the working temperature. The comparison between experimental and calculation results shows that this method is effective as a designing step with only the time-domain voltage and current data obtained from simulation results.

The Restructuring of Food Systems: Trends, Research, and Policy Issues

Abstract: This issue brings together a selection of articles based on presentations at two Conferences in 1997. The aim has been 1) to offer clearer and more understandable descriptions of the major trends and relationships that are involved in the structural transformations that are occurring in food systems at all levels; 2) to help develop better theoretical and conceptual tools to aid us in analyzing such restructurings and their dynamics; and 3) to clarify a number of practical issues facing those seeking to promote more sustainable and just food systems, especially at the local level. With only one exception, all the articles here focus on Western economies where food systems are highly commodified, globally integrated, corporate, and state structures have been restructured by a series of neo-liberal reforms in recent years. In pointing out the problems with these food systems, the articles also discuss various possibilities for structural reforms for more healthy, sustainable, just, and equitable food systems and societies.

Comprehensive analysis of edge detection in color image processing

Abstract: Various approaches to edge detection for color images, in- cluding techniques extended from monochrome edge detection as well as vector space approaches, are examined. In particular, edge detection techniques based on vector order statistic operators and difference vec- tor operators are studied in detail. Numerous edge detectors are ob- tained as special cases of these two classes of operators. The effect of distance measures on the performance of different color edge detectors is studied by employing distance measures other than the Euclidean norm. Variations are introduced to both the vector order statistic opera- tors and the difference vector operators to improve noise performance. They both demonstrate the ability to attenuate noise with added algo- rithm complexity. Among them, the difference vector operator with adap- tive filtering shows the most promising results. Other vector directional filtering techniques are also introduced and utilized for color edge detec- tion. Both quantitative and subjective tests are performed in evaluating the performance of the edge detectors, and a detailed comparison is presented. © 1999 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(99)00904-6)

Simulating Performance Impacts of Bus Lanes and Supporting Measures

Abstract: This study used the TRANSYT-7F simulator to examine changes in performance measures of through buses and adjacent traffic following the introduction of reserved lanes in an urban arterial. In addition, the TRANSYT-7F simulator was used to examine the specific impacts on modal performance of two policy measures implemented in conjunction with lane introduction. The results showed that TRANSYT-7F provided relatively accurate estimates of bus delays and auto speeds. However, the study identified one area of improvement for TRANSYT-7F to model priority treatments on arterials more effectively. The simulation results showed that the performance of the average bus improved after project implementation, whereas the performance of the adjacent through traffic deteriorated. However, the deterioration exceeded the improvement. Other aggregate estimates of performance were examined and discussed. The simulations also showed that modifications to left-turn movements would have a minor impact on both bus and adjacent traffic performance, whereas the removal of taxis from the reserved lanes would cause far more performance deterioration to the adjacent traffic than the performance improvement this policy measure would bring to buses.

Automatic location and tracking of the facial region in color video sequences

Abstract: A novel technique is introduced to locate and track the facial area in videophone-type sequences. The proposed method essentially consists of two components: (i) a color processing unit, and (ii) a knowledge-based shape and color analysis module. The color processing component utilizes the distribution of skin-tones in the HSV color space to obtain an initial set of candidate regions or objects. The second component in the segmentation scheme, that is, the shape and color analysis module is used to correctly identify and select the facial region in the case where more than one object has been extracted. A number of fuzzy membership functions are devised to provide information about each object’s shape, orientation, location and average hue. An aggregation operator finally combines these measures and correctly selects the facial area. The suggested approach is robust with regard to di⁄erent skin types, and various types of object or background motion within the scene. Furthermore, the algorithm can be implemented at a low computational complexity due to the binary nature of the operations involved. Experimental results are presented for a series of CIF and QCIF video sequences. ( 1999 Elsevier Science B.V. All rights reserved.

Valuation of European Options Subject to Financial Distress and Interest Rate risk

Abstract: Like the previous article, Klein and Inglis focus on credit risk. But in this case, it is the credit worthiness of the writer of a derivative instrument whose solvency is at issue. The risk of default on a vulnerable contract depends on the (correlated) changes in the value of the underlying for the derivative instrument, the value of the assets of the firm that writes the contract, and the risk-free interest rate. This article derives closed-form valuation equations for vulnerable European calls and puts and presents a number of numerical examples to illustrate the impact of the different model parameters on option value relative to Black-Scholes.

Chinese commercial activity in the toronto cma: new development patterns and impacts

Abstract: This study, which examines recent development patterns of Chinese commercial activity in the Toronto CMA, yielded three major discoveries. First, new development in the past 15 years brought about not only a proliferation of ethnic Chinese businesses, but also considerable changes in business structure: the traditionally predominant restaurants and grocery stores declined substantially in proportion, but businesses that provide various types of consumer services expanded greatly. This indicates that the Chinese community has been steadily building a more complete and more self-sufficient ethnic economy. Second, while Toronto's three central-city Chinatowns have remained, most new developments occurred in the suburbs. Consequently, the spatial organization of Chinese commercial activities has become multinuclear, and their rapid spreading has begun to modify Toronto's traditional retail landscape. The third, and perhaps the most revolutionary, characteristic of the new development is the shift from unplanned retail strips to planned shopping centres, with the change of ownership from leasing of retail space to selling of store units. The new occupancy system, known as condominium retailing, is new to Canada and is associated only with ethnic Chinese retailing. In importance, condominium retailing has challenged both the conventional leasing system that has governed the development and operation of North American shopping centres over the past 40 years and long-established local planning systems. L'etude des nouvelles tendances du commerce chinois dans la region metropolitaine de recensement de Toronto a mis en evidence trois faits essentiels. Premierement, le developpement des 15 dernieres annees s'est traduit non seulement par une multiplication du nombre des commerces chinois, mais aussi par un bouleversement de la structure commerciale: les restaurants et les epiceries, jusqu'alors predominants, ont vu leur importance relative diminuer au profit de magasins qui offrent des services aux consommateurs. Ceci reflete le fait que l'economie forgee par la communaute chinoise est de plus en plus autosuffisante. Deuxiemement, alors que les trois Chinatowns du centre de Toronto se sont maintenus, la plupart des nouveaux developpements ont eu lieu en banlieue. Par consequent, l'organisation spatiale des activites commerciales chinoises est devenue polynucleaire. Cette rapide propagation commence a modifier le paysage traditionnel du commerce de detail torontois. Troisiemement, et c'est peut-etre la le fait le plus marquant, l'etude a revele une revolution complete du mode d'organisation et de propriete des magasins. Aux groupements spontanes se sont substitues des centres commerciaux au sein desquels les commercants ne sont plus locataires mais proprietaires de leur espace de vente. Ce systeme, que l'on pourrait baptiser le « condominium commercial » est un nouveau phenomene au Canada et ne concerne, pour l'instant, que les commerces chinois. Neanmoins, par son succes, le « condominium commercial » a remis en question les systemes traditionnels de planification locale, aussi bien que le systeme classique des baux, qui a preside au developpement des centres commerciaux nord-americains au cours des 40 dernieres annees.

Energy and exergy analyses of cold thermal storage systems

Abstract: This study deals with the assessment of the thermodynamic performance of cold thermal storage systems using exergy and energy analyses. Several cases are considered, including some storages which are homogeneous, and others which undergo phase changes. In some cases the storages are stratified. A full cycle of charging, storing and discharging is considered for each case. Four cold thermal storage cases are presented in an illustrative example. The results demonstrate that exergy analysis provides more realistic and accurate assessments of the efficiency and performance of cold thermal storage systems than those given by the more conventional energy analysis. In addition, exergy analysis is conceptually more direct since it treats cold as a valuable commodity. It is concluded that the potential usefulness of exergy analysis in addressing and solving cold thermal storage problems is substantial. Copyright © 1999 John Wiley & Sons, Ltd.

High temperature creep deformation of Al18B4O33 whisker-reinforced 8009 Al composite

Abstract: The compression creep deformation of an Al18B4O33 whisker-reinforced Al-Fe-V-Si (8009 Al alloy) composite has been investigated in the temperatures range from 573 to 723 K. The addition of 15 vol.% Al18B4O33 whiskers to the 8009 alloy decreases the creep rate by two orders of magnitude compared to the 8009 alloy. The stress and temperature dependence of the creep rate of the composite is similar to that of the 8009 alloy. The threshold stress for creep was used to analyze the experimental data for the composite. The creep rates of the composite are shown to be controlled by lattice diffusion of aluminum. The contribution of the whiskers on creep rate of the composite is interpreted by a modified load-transfer model. (C) 1999 Elsevier Science S.A. All rights reserved.

Interactive Medical Image Segmentation with United Snakes

Abstract: Snakes have become a standard image analysis technique with several variants now in common use. We have developed a software package called “United Snakes”. It unifies the most important snake variants, including finite difference, B-spline, and Hermite polynomial snakes, within the framework of a general finite element formulation with a choice of shape functions. Furthermore, we have incorporated into united snakes a recently proposed snake-like technique known as “livewire”, via a method for imposing hard constraints on snakes. Here, we demonstrate that the combination of techniques in united snakes yields generality, accuracy, ease of use, and robustness in several medical image analysis applications, including the segmentation of neuronal dendrites in EM images, dynamic chest image analysis, and the quantification of growth plates.

Dynamic modeling of interstitial laser photocoagulation: implications for lesion formation in liver in vivo.

Abstract: BACKGROUND AND OBJECTIVE: Interstitial Laser Photocoagulation (ILP) is a minimally invasive cancer treatment technique, whereby optical energy from implanted optical fibers is used to therapeutically heat small, solid tumors. In this work, the potential of ILP without tissue charring is investigated. STUDY DESIGN/MATERIALS AND METHODS: Optical diffusion and bio-heat transfer equations were used to develop dynamic models of interstitial laser heating in liver in vivo. Modifications in the optical properties due to tissue coagulation (T > or = 60 degrees C) were incorporated into the physical description. In addition, the effect of three different blood perfusion patterns on temperature distributions was explored. Model-predicted temperatures were used as an index for thermal damage based on an accumulated temperature injury (Arrhenius) model. Thermal damage dimensions were determined with tissue temperatures constrained to remain below 100 degrees C, so as to minimize the potential for tissue charring and smoke production. RESULTS: The model predicts that increases in scattering due to coagulation and choice of perfusion pattern affect substantially thermal damage dimensions. The results indicate that, for single fiber ILP at 2.55 W for 600 s, the maximum achievable thermal damage diameter in liver, without charring, is 9.6 mm. In addition, ILP performed with high-low power ramping may have an advantage over constant power treatments, in that, larger volumes of thermal damage can be realized earlier in an irradiation. CONCLUSIONS: For ILP performed with a single spherical emitting fiber, optimal irradiation parameters exist such that thermal lesions in liver up to approximately 10 mm in diameter can be induced while the maximum tissue temperature remains below 100 degrees C, avoiding tissue charring.

Providing mark-up and feedback to students with online marking

Abstract: Online marking of assignments can lead to improved marking consistency and integrate well with on-line mark reporting. It can also be easier for the marker. Unfortunately, most such systems do not include good feedback mechanisms for the students. This paper describes an environment that provides online marking with convenient, structured and detailed feedback.

What Is My Child Learning at Elementary School? Culturally Contested Issues between Teachers and Latin American Families

Abstract: /RESUME This study is part of an extensive research project on children of Latin American immigrants, their teachers and families. Through participant observation in one designated Canadian school, we captured the perspectives of ten students, their parents and teachers. An additional thirty-five families from other elementary schools in Toronto were interviewed to test the trustworthiness of the initial analysis. From the stories of these families and our knowledge of their children's schools, we describe how the parents' practices interact with mainstream practices and how the former are constructed within the present school system. Findings reported include: 1) Issues in communication involved teachers' use of educational terms that the parents did not understand. Teachers' positively slanted reports of the children's progress were not understood as indicating the genuine weakness of the child's performance. 2) In most cases, the family's support was not effective in helping children improve their grades at school , and this resulted in family conflicts and parents becoming disengaged from their children's academic tasks. 3) Children and parents expected a more personal approach than the teachers provided. It is concluded that a critical interrogation of the structures of educational delivery is needed as well as attention to the perceptions, beliefs, goals and knowledge of minority parents. La presente etude fait partie d'un projet de recherche approfondi sur les enfants des immigrants de l'Amerique Latine, leurs enseignants et leurs familles. Grace 1'observation des participants dans une ecole canadienne designee, nous avons capte les points de vue de dix eleves, de leurs parents et de leurs enseignants. Trente-cinq autres families dans d' autres ecoles elementaires a Toronto ont passe des entrevues afin de verifier la verite de l'analyse initiale. En se basant sur les histoires de ces families et notre connaissance des ecoles de leurs enfants, nous decrivons comment les methodes des parents interagissent avec les methodes courantes, et comment celles-ci sont concues a l'interieur du systeme scolaire actuel. Les conclusions rapportees comprennent 1) Les problemes de communication concernent l'utilisation par les enseignants de termes pedagogiques que les parents ne comprenaient pas. Les rapports orientes positivement des enseignants sur les progres des enfants n'etaient pas compris comme indiqu ant la faiblesse reelle de la performance de 1' enfant. 2) Dans la plupart des cas, l' appui de la famille n' etait pas efficace pour aider les enfants a ameliorer leurs notes a l'ecole. Cela entrainait des conflits et les parents se retiraient des taches scolaires de leurs enfants. 3) Les enfants et les parents esperaient une attitude plus personnelle que celle offerte par les enseignants. II a ete conclu qu'un questionnement essentiel des structures de diffusion pedagogique est necessaire, ainsi qu'une attention aux perceptions, aux croyances, aux buts et aux connaissances des parents minoritaires. Mrs. Lorca (1) (speaking of her Nicaraguan Canadian daughter, eight years of age): I would like to know what it is that Monica needs? Why in the report cards the teacher says she needs more math, more reading and at home ...? Although we don't speak much English, we are always helping her in everything. She always does her homework and knows everything we ask her, but the report card always arrives as if she is failing. Mrs. Cordoba (speaking of her Guatemalan Canadian son, thirteen years of age): It is very worrisome that an intelligent child like Roberto needs Learning Centre year after year and does not progress sufficiently to be at grade level; it has been three years already. I am worried that our children are streamed into these programs and the teachers do not say why the problems occur and do not seem to come up with any solutions. I want to know who the teacher is at Learning Centre, what they teach and what he does in that class. …

The therapeutic use of music for dyspnea and anxiety in patients with COPD who live at home.

Abstract: The purposes of this repeated measures study were to examine the feasibility of using music as an intervention for dyspnea and anxiety in patients with chronic obstructive pulmonary disease (COPD) who live in their homes and to examine the effect of music on anxiety and dyspnea. Twenty-four participants who experienced dyspnea at least once a week were studied over a 5-week period. Baseline data were collected on Week 1. Measures of anxiety and dyspnea were taken on Week 2, prior to and immediately following the use of music. These measures were repeated on Week 5. There was a significant decrease in dyspnea following the use of music as reported in the music diary (p < .001). There was a significant decline in anxiety (p < .05) and dyspnea (p < .01) following the use of music on Week 2. There was no significant change in anxiety or dyspnea over the 5-week period.

Optimising stability bounds of finite-precision controller structures for sampled-data systems in the /spl delta/-operator domain

Abstract: A tractable closed-loop stability-related measure for controller structures, realised using the /spl delta/ operator and digitally implemented with 'finite word length' (FWL), is derived. The optimal realisations of the general finite-precision controller are defined as those that maximise this measure and are shown to be the solutions of a constrained nonlinear optimisation problem. For the special case of digital PID controllers, the constrained problem can be decoupled into two simpler unconstrained optimisation problems. A global optimisation strategy based on the adaptive simulated annealing is adopted to provide an efficient method for solving this complex optimal realisation problem. Two numerical examples are presented to illustrate the design procedure, and the simulation results confirm that the optimal FWL realisations of the /spl delta/-operator based controller have better closed-loop stability margins than those of the usual shift-operator based controller, especially under fast sampling conditions.

The Intimate Connection Between Exergy and the Environment

Abstract: It is well known that there is always an environmental cost associated with the thermal, chemical, and/or nuclear emissions which are a necessary consequence of carrying out the processes that give benefits to mankind. The environmental impact of emissions is reduced by increasing the efficiency of resource utilization. Sometimes, in practice, this is referred to as “energy conservation.” However, increasing efficiency generally entails greater use of materials, labor, and more complex devices. The additional cost may be justified by the added security associated with a decreased dependence on energy resources and by the social peace obtained through increased productive employment.

Thermal storage and exergy analysis: the impact of stratification

Abstract: The importance and usefulness of second-law analysis for evaluating and comparing thermal energy storage (TES) systems in meaningful ways is discussed. Some of the main thermodynamic factors to be ...