198 research outputs found
Design for latitude
"The purposes of this thesis are threefold: (1) to provide an introduction to the Taguchi philosophy and its methodologies, (2) to integrate the Taguchi philosophy of quality loss with nonlinear programming both without and with constraints, and (3) to compare the conventional Taguchi approach and the nonlinear programming approach to engineering design optimization. Part I of the thesis provides an introduction to Taguchi methods. Chapter One introduces Taguchi1s perspective of quality and losses attributable to poor quality. Also covered are different design objectives and how these are related to quality. Chapter Two develops the methods for implementing Taguchi's concepts of quality. Part II considers the Taguchi concept of quality loss as the optimization criterion. Chapter Three uses the Taguchi quality loss function given in the first chapter as the objective function; however nonlinear programming, not experimental design, is the vehicle used to perform the design optimization. Chapter Four investigates the fully constrained optimization problem by treating constraints as additional objective terms thereby creating an equivalent multicriterion problem. Part III completes the thesis by summarizing the results of the work. The comparison of results is given in Chapter Five. Chapter Six discusses these results. Chapter Seven concludes the thesis and suggests topics for additional work. Dr. Taguchi1s methods are based on fundamental concepts in statistics. However, because this work is not oriented towards the statistician, statistics will be introduced only when absolutely necessary. Appendix A covers the basic statistical and probabilistic concepts required by the thesis. Appendix B contains the derivations of the mathematical expectations of formulae used in the thesis. Computer listings of example problem runs are given in Appendix C. These appendices are contained, along with the references, in Part IV."--Preface.Includes bibliographical references
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Circles of Influence: Rational decision-making, strategic positioning, and the formation of charter school clusters in New Jersey
A major focus of charter school research has been the potential impact of increased school choice on student sorting by race/ethnicity and socio-economic status. Researchers have argued that charter schools may increase segregation by allowing families to separate into more homogeneous school communities. Yet surprisingly, little attention has been paid to the role charter schools themselves may play in determining student enrollments. Emerging evidence suggests that charter schools may frequently take into account nearby educational and demographic characteristics when choosing school locations and avoid neighborhoods with high-proportions of at-risk students who are more costly and challenging to educate. While this behavior is not incompatible with traditional notions of how education marketplaces function, such "positioning strategies" serve as important reminders that charter schools benefit most by locating in areas where they hold clear competitive advantages, not necessarily areas of greatest demand or educational need. In this dissertation, I examined the potential for New Jersey charter schools to effectively distribute educational opportunities to all students, particularly those most frequently targeted by previous approaches to school reform, across varied and often segregated landscapes. Drawing on rational choice theory and previous research into the profit maximizing behavior of firms, I argued that charter schools have strong incentives to locate in areas that allow them to effectively balance consumer demand with the potential negative effects of increased competition in high needs areas. I used geographic information systems (GIS) and logistic regression to map the location of charter schools in New Jersey and examine potential associations with supply side factors. New Jersey's charter school supply showed two distinct clustering patterns. First, charter schools tended to circle Abbott districts or low-performing school districts in a narrow five mile band characterized by greater educational need and, presumably, consumer demand. Second, charter schools in Abbott districts tended to circle, but not locate within, neighborhoods with higher levels of educational and economic disadvantage, and particularly neighborhoods with higher proportions of African American residents. Logistic regression confirmed statistically significant associations among charter school clusters and proxies for market demand, educational need, and neighborhood diversity, although estimates for race/ethnicity were less conclusive. Further analysis indicated that observed clustering patterns were primarily driven by more market savvy or entrepreneurial schools partnered with charter management organizations (CMOs)
Ostensive signals support learning from novel attention cues during infancy
Social attention cues (e.g., head turning, gaze direction) highlight which events young infants should attend to in a busy environment and, recently, have been shown to shape infants' likelihood of learning about objects and events. Although studies have documented which social cues guide attention and learning during early infancy, few have investigated how infants learn to learn from attention cues. Ostensive signals, such as a face addressing the infant, often precede social attention cues. Therefore, it is possible that infants can use ostensive signals to learn from other novel attention cues. In this training study, 8-month-olds were cued to the location of an event by a novel non-social attention cue (i.e., flashing square) that was preceded by an ostensive signal (i.e., a face addressing the infant). At test, infants predicted the appearance of specific multimodal events cued by the flashing squares, which were previously shown to guide attention to but not inform specific predictions about the multimodal events (Wu and Kirkham, 2010). Importantly, during the generalization phase, the attention cue continued to guide learning of these events in the absence of the ostensive signal. Subsequent experiments showed that learning was less successful when the ostensive signal was absent even if an interesting but non-ostensive social stimulus preceded the same cued events
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Development and Validity of the Teachers' Attitude, Comfort and Training Scale (TACTS) on Sexuality Education
The purpose of the study was to design and validate an instrument designed to investigate teachers' attitudes in regard to adolescent sexuality education. Test development adhered to the guidelines of Aligna and Crocker. Cronbach alpha was performed on the entire instrument and determined the reliability to be .8003, thus the instrument was consistent in measuring the domain areas. A panel of experts assessed content validity of items. A principal component factor analysis and a Pearson's product moment correlation were used for construct validity. Teacher concerns about curriculum
implementation, teacher comfort with the subject matter, course-specific teacher attitudes, teacher interest about curriculum content, and teacher attitudes toward sexuality were found to be the constructs of the TACTS
Cloud analysis using NOAA-7 AVHRR multispectral imagery
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984.Microfiche copy available in Archives and Science.Bibliography: leaves 78-79.by Robert Paul d'Entremont.M.S
Mondialisation et souveraineté de l'état : le projet souverainiste québécois est-il toujours pertinent?
Ce mĂ©moire a pour but d'explorer les effets de la mondialisation sur la souverainetĂ© de l'Ătat ainsi que les dĂ©fis qu'elle lui pose. Il porte principalement sur l'angle Ă©conomique du phĂ©nomĂšne de mondialisation. Nous voulons apporter des Ă©lĂ©ments de rĂ©flexion au dĂ©bat sur la pertinence de la souverainetĂ© politique du QuĂ©bec dans le contexte de la mondialisation. Nous avançons que cette avenue politique est une option toujours pertinente dans le contexte mondial actuel et qu'elle est mĂȘme souhaitable pour le dĂ©veloppement futur du QuĂ©bec. Nous exposons d'abord le cadre thĂ©orique sur lequel nous nous appuyons tout au long de ce mĂ©moire. Ensuite, nous vĂ©rifions si la multiplication des organisations et des accords internationaux reprĂ©sentent effectivement une menace Ă la souverainetĂ© de l'Ătat. Pour ce faire, nous Ă©tudions les effets contraignants du Fonds monĂ©taire international, de l'Organisation mondiale du commerce et de l'Accord de libre-Ă©change Nord-AmĂ©ricain. Nous nous penchons aussi sur l'impĂ©ratif de compĂ©titivitĂ© qui incombe aux Ătats dans le contexte de mondialisation. Finalement, nous voyons comment le QuĂ©bec peut prendre exemple sur certains petits Ătats europĂ©ens comme l'Autriche ou les Pays-Bas qui connaissent des succĂšs malgrĂ© leur grande ouverture Ă©conomique, et ce, grĂące Ă leur flexibilitĂ© et leur capacitĂ© d'adaptation face aux pressions extĂ©rieures de l'Ă©conomie. Nous Ă©tudions les pratiques nĂ©ocorporatistes qui caractĂ©risent le fonctionnement interne de ces pays et nous nous penchons sur l'importance de la solidaritĂ© sociale dans le succĂšs de ces pratiques. Nous dĂ©couvrons comment il est possible de favoriser cette solidaritĂ© en nous appuyant sur le concept de capital social et nous terminons par la proposition de faire de la langue française l'Ă©lĂ©ment identitaire rassembleur qui puisse renforcer les arrangements nĂ©ocorporatistes et permettre un meilleur dĂ©veloppement socioĂ©conomique du QuĂ©bec. Nous concluons que l'Ătat n'est pas complĂštement contraint par la mondialisation mais que celle-ci comporte son lot de dĂ©fis auxquels il doit rĂ©pondre pour assurer sa prospĂ©ritĂ© dans une Ă©conomie mondialisĂ©e. Nous croyons que le QuĂ©bec possĂšde des atouts majeurs pour assurer son dĂ©veloppement et que la souverainetĂ© politique lui permettrait de mieux les exploiter. ______________________________________________________________________________ MOTS-CLĂS DE LâAUTEUR : Mondialisation, SouverainetĂ©, QuĂ©bec, Capital social
DEVELOPMENT OF A SLURRY-FED IN-CAN MELTER FOR NUCLEAR DEFENSE WASTE
The Savannah River Plant (SRP) has about 30 million gallons of high-level, radioactive, liquid waste stored in large waste tanks. This waste is a by-product of the production of nuclear defense materials at SRP. Plans are to build the Defense Waste Processing Facility (DWPF) at SRP to convert this waste into solid form. A key step in the planned DWPF process is the vitrification or glassmaking step, in which the radionuclides are incorporated in borosilicate glass. Two types of glass melters have been developed for this step. The planned melter design for the DWPF is a slurry-fed, continuous, joule-heated melter. The backup melter design is an in-can melter. Previous plans were to dry and partially calcine the radioactive waste sludge before feeding it to the in-can melter. However, it was desirable to eliminate the drying step and feed the waste sludge as a liquid. Eliminating the drying step simplified the process and reduced the project cost. At the Savannah River Laboratory (SRL), a full-scale in-can melter of the former dry-fed design was converted to slurry feeding by adding appropriate feed and off-gas systems. Five experimental runs were made with this process from August to December 1981. The purpose of this program was to demonstrate the basic process, determine key process variables such as rate and off-gas system requirements, and identify potential problems with long-term operation. A full-scale, nonradioactive process has been studied in which a slurry of waste sludge and glass formers is fed to a heated can. Saturated steam is used to cool the off-gas. Initial results show the concept to be technically adequate
Canadian Estimate of Bird Mortality Due to Collisions and Direct Habitat Loss Associated with Wind Turbine Developments
We estimated impacts on birds from the development and operation of wind turbines in Canada considering both mortality due to collisions and loss of nesting habitat. We estimated collision mortality using data from carcass searches for 43 wind farms, incorporating correction factors for scavenger removal, searcher efficiency, and carcasses that fell beyond the area searched. On average, 8.2 ± 1.4 birds (95% C.I.) were killed per turbine per year at these sites, although the numbers at individual wind farms varied from 0 - 26.9 birds per turbine per year. Based on 2955 installed turbines (the number installed in Canada by December 2011), an estimated 23,300 birds (95% C.I. 20,000 - 28,300) would be killed from collisions with turbines each year. We estimated direct habitat loss based on data from 32 wind farms in Canada. On average, total habitat loss per turbine was 1.23 ha, which corresponds to an estimated total habitat loss due to wind farms nationwide of 3635 ha. Based on published estimates of nest density, this could represent habitat for ~5700 nests of all species. Assuming nearby habitats are saturated, and 2 adults displaced per nest site, effects of direct habitat loss are less than that of direct mortality. Installed wind capacity is growing rapidly, and is predicted to increase more than 10-fold over the next 10-15 years, which could lead to direct mortality of approximately 233,000 birds / year, and displacement of 57,000 pairs. Despite concerns about the impacts of biased correction factors on the accuracy of mortality estimates, these values are likely much lower than those from collisions with some other anthropogenic sources such as windows, vehicles, or towers, or habitat loss due to many other forms of development. Species composition data suggest that < 0.2% of the population of any species is currently affected by mortality or displacement from wind turbine development. Therefore, population level impacts are unlikely, provided that highly sensitive or rare habitats, as well as concentration areas for species at risk, are avoided
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