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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

A THEORY OF SIGNAL DETECTION BASED UPON HYPOTHESIS ANALYSIS

Fobes, James L. January 1975 (has links)
No description available.
32

A Fault-Aware Resource Manager for Multi-Processor System-on-Chip

Ghaeini, Bentolhoda January 2013 (has links)
The semiconductor technology development empowers fabrication of extremelycomplex integrated circuits (ICs) that may contain billions of transistors. Suchhigh integration density enables designing an entire system onto a single chip,commonly referred to as a System-on-Chip (SoC). In order to boost performance,it is increasingly common to design SoCs that contain a number of processors, socalled multi-processor system-on-chips (MPSoCs).While on one hand, recent semiconductor technologies enable fabrication ofdevices such as MPSoCs which provide high performance, on the other hand thereis a drawback that these devices are becoming increasingly susceptible to faults.These faults may occur due to escapes from manufacturing test, aging effects orenvironmental impacts. When present in a system, faults may disrupt functionalityand can cause incorrect system operation. Therefore, it is very importantwhen designing systems to consider methods to tolerate potential faults. To copewith faults, there is a need of fault handling which implies automatic detection,identification and recovery from faults which may occur during the system’s operation.This work is about the design and implementation of a fault handling methodsfor an MPSoC. A fault aware Resource Manager (RM) is designed and implementedto obtain correct system operation and maximize the system’s throughputin the presence of faults. The RM has the responsibility of scheduling jobs to availableresources, collecting fault states from resources in the system and performingfault handling tasks, based on fault states. The RM is also employed in multipleexperiments in order to study its behavior in different situations.
33

Endurance exercise in chronic obstructive pulmonary disease

Revill, Susan M. January 1997 (has links)
No description available.
34

The validity of polytomous items in the Rasch model - The role of statistical evidence of the threshold order

Salzberger, Thomas January 2015 (has links) (PDF)
Rating scales involving more than two response categories are a popular response format in measurement in education, health and business sciences. Their primary purpose lies in the increase of information and thus measurement precision. For these objectives to be met, the response scale has to provide valid scores with higher numbers reflecting more of the property to be measured. Thus, the response scale is closely linked to construct validity since any kind of malfunctioning would jeopardize measurement. While tests of fit are not necessarily sensitive to violations of the assumed order of response categories, the order of empirical threshold estimates provides insight into the functionality of the scale. The Rasch model and, specifically, the so-called Rasch-Andrich thresholds are unique in providing this kind of evidence. The conclusion whether thresholds are to be considered truly ordered or disordered can be based on empirical point estimates of thresholds. Alternatively, statistical tests can be carried out taking standard errors of threshold estimates into account. Such tests might either stress the need for evidence of ordered thresholds or the need for a lack of evidence of disordered thresholds. Both approaches are associated with unacceptably high error rates, though. A hybrid approach that accounts for both evidence of ordered and disordered thresholds is suggested as a compromise. While the usefulness of statistical tests for a given data set is still limited, they provide some guidance in terms of a modified response scale in future applications.
35

Threshold Regression Estimation via Lasso, Elastic-Net, and Lad-Lasso: A Simulation Study with Applications to Urban Traffic Data

January 2015 (has links)
abstract: Threshold regression is used to model regime switching dynamics where the effects of the explanatory variables in predicting the response variable depend on whether a certain threshold has been crossed. When regime-switching dynamics are present, new estimation problems arise related to estimating the value of the threshold. Conventional methods utilize an iterative search procedure, seeking to minimize the sum of squares criterion. However, when unnecessary variables are included in the model or certain variables drop out of the model depending on the regime, this method may have high variability. This paper proposes Lasso-type methods as an alternative to ordinary least squares. By incorporating an L_{1} penalty term, Lasso methods perform variable selection, thus potentially reducing some of the variance in estimating the threshold parameter. This paper discusses the results of a study in which two different underlying model structures were simulated. The first is a regression model with correlated predictors, whereas the second is a self-exciting threshold autoregressive model. Finally the proposed Lasso-type methods are compared to conventional methods in an application to urban traffic data. / Dissertation/Thesis / Masters Thesis Industrial Engineering 2015
36

Hearing protection in mines : evaluating the Noise Clipper® custom made hearing protection device

Kock, Johan Frederick Willem 14 June 2013 (has links)
Noise induced hearing loss has been extensively researched and commented on, yet it remains prevalent among industrial workers. The real-world attenuation properties of the Noise Clipper® custom-made hearing protection device and the comfort levels it afford are unknown. Furthermore, research in hearing conservation is seldom focused on the critical/biological thresholds for temporary threshold shift. Field studies on hearing protection devices have demonstrated that laboratory derived measures bear little relation to attenuation achieved in workers. Research has consistently demonstrated that noise reduction ratings that are derived from the laboratory real-ear-at-threshold method do not accurately represent the attenuation of noise that these devices actually provide and the matter remains unclear. Too many important variables are neglected in current real-ear-atthreshold evaluation protocols. This study used an alternative method, the microphone-inreal- ear approach where a dual-element microphone probe was inserted into the Noise Clipper® to measure noise reduction by recording the difference in noise levels outside and behind the device. The sub aims of the study were to record ambient noise levels and frequency spectra; to determine the attenuation characteristics; and to compare the attenuation thresholds to biological thresholds for temporary threshold shift. Using this protocol, measurements were made on 20 subjects in real world situations in order to match the attenuation characteristics of the Noise Clipper® to the actual noise exposure. The microphone-in-real-ear derived attenuation thresholds were compared to the real-earat- threshold values provided by the manufacturer of the Noise Clipper®. Additional subaims were to determine the comfort levels of the Noise Clipper® and record the selfreported wearing time of the device. Wearing comfort was evaluated using a bipolar rating scale. The researcher interviewed 240 mine workers at a platinum mine. Several comfort related sub-scales were used to quantify reported comfort levels. Simultaneously, usage time of the device was self-reported by each worker. Results of the microphone-in-real-ear measurements indicated that ambient noise levels fluctuated from day to day. The attenuation results indicated that most of the measurements suggested protection against noise induced hearing loss through the use of the Noise Clipper®. It was found that the REAT results over estimated the attenuation ability of the Noise Clipper® when compared to the results of the F-MIRE measurements. Eighty seven percent of the measurements indicated protection from thresholds below the biological threshold for temporary threshold shift. Seventy five percent of the workers indicated that the Noise Clipper® was comfortable to wear and 79% indicated that they used it for a full eight hour shift. The results provide an opportunity to assess the use of a protection device and its effectiveness among mineworkers combined with information regarding noise exposure levels. The findings highlight the importance of evaluating variability in terms of individual-specific protection. / Dissertation (MCommunication Pathology)--University of Pretoria, 2013. / Speech-Language Pathology and Audiology / unrestricted
37

The monster : liminality, threshold and spatial experience

Coetzee, Izak Johannes 24 November 2008 (has links)
Victor Turner (in Dodds, 1992: 82) suggests to take every day elements and rearrange them in ways not experienced every day is to create a “monster”, which will achieve liminality in architecture. The titel of this dissertation is a result of this phenomenon. In this design investigation ways to transform liminality into a building are explored. Smith (2000) states, “liminality or the liminal refers to transitional space; neither one place nor another; neither one discipline nor another; rather a thirdspace in-between”. Various devices were examined to facilitate the transition from abstract concept into architectural possibility. The following devices: typology, technology, spatial experience, interlocking volumes, superimposition, programmatic bands and atmospheric effects have been examined. The final product is a fusion of theoretical notions and technology expressed as a hybridized typology, all these qualities are arranged in ways not experienced every day, resulting in a building called the Monster. / Dissertation (MArch(Prof))--University of Pretoria, 2009. / Architecture / unrestricted
38

Essays on Corporate Finance and Interest Rate Policy

Yao, Haibo 15 August 2014 (has links)
My research makes three contributions to the literature. The first contribution is to find supportive evidence for the augmented Taylor rule model with orthogonalized bond market variables I build to more accurately describe and forecast the behavior the Federal Reserve, with improved model’s fit both in and out-of-sample. The second contribution to the existing literature is that I find supportive evidence for a macro explanation of industrial firm behavior in the United States. The third contribution of this paper is that I provide a new aspect to understand the monetary policy and the monetary policy transmission mechanism for both monetary policy practitioners and researchers. This research proceeds as the following: Essay one provides a literature review for the research in this dissertation discussing background and theories for both the empirical and theoretical applications of the Taylor rule, a tool for the setting of the federal funds rate. The second essay is designed to understand the setting of monetary policy by the Federal Reserve. I show that augment a simple Taylor rule with bond market information can significantly improve the model’s fit, both in and out-of-sample. The improvement is enough to produce lower forecast errors than those of non-linear policy models. In addition, the inclusion of these bond market variables resolves the parameter instability of the Taylor rule documented in the literature, and implies that the lagged federal funds rate plays a much smaller role than that suggested in the previous studies. The third essay examines the impact of monetary shocks on corporate cash holdings. I find evidence that small industrial firms hold onto cash when monetary policy is too tight and large industrial firms do the reverse both in the short-run and in the long-run. Further tests examine whether the long lasting loose monetary policy results in the pileup of corporate cash holdings. The evidence supports the assumption that industrial firms take the “long lasting lower interest rate” environment to hoard cash to buffer the monetary policy effectiveness.
39

Contextualization and Sodium Diet Implications of Occoquan Reservoir Salinization

Shipman, Caitlin Mariah 17 March 2023 (has links)
Freshwater salinization syndrome is a rising threat globally which results in increased ion concentrations in inland freshwaters. This syndrome threatens healthy aquatic ecosystems and can alter the perception of the potability of finished drinking water. The Occoquan Reservoir, located in Northern Virginia, is a freshwater system that is facing rising salinization. Stakeholders for the reservoir have been convened to address these rising salinization concerns. Among these stakeholders, there are a variety of viewpoints on the significance of the salinization, which is preventing a high level of convergence around this threat. To assist in contextualizing this system, empirical cumulative distribution functions were generated from data gathered from various governmental sources and compared the reservoir's watershed and finished drinking water ion concentrations. These analyses show that the watershed and finished drinking water have some of the highest concentrations of sodium and chloride statewide. Additional investigations determined the trend of sodium increases in finished drinking water since the 1980s. Monte Carlo simulations were ran to determined whether there would be risks to human from ingesting this water should this trend continued. Results from these analyses greatly varied due to the wide range in drinking water ingestion rates. The purpose of these analyses is to assist with stakeholder convergence around the level of threat salinization poses to the reservoir and to initiate discussions of what an acceptable threshold for management could be. / Master of Science / Freshwater salinization syndrome is a rising threat globally which results in increased ion concentrations in inland freshwaters. This syndrome threatens healthy aquatic ecosystems and can alter the perception of the potability of finished drinking water. The Occoquan Reservoir, located in Northern Virginia, is a freshwater that is facing rising salinization. Stakeholders for the reservoir have been convened to address these concerns. Among the stakeholders, there are a variety of viewpoints on the significance of salinization. Various analyses were done to compare the sodium and chloride concentrations in the reservoir's watershed and in the finished drinking water with respective statewide levels. These analyses show that the watershed and finished drinking water have some of the highest concentrations of sodium and chloride statewide. Additional investigations were conducted to determine if there was a human health risk to consuming the finished drinking water. Results from this analysis were highly dependent on how much water an individual consumed. The purpose of these analyses is to assist with stakeholder convergence around the level of threat salinization poses to the reservoir and to initiate discussions of what an acceptable threshold for management could be.
40

Thresholds in Space and Time

Asbell, Jonathan Clark 23 November 2020 (has links)
In architecture there is perhaps no better opportunity to capture movement and change than in the design of thresholds. They can be a simple strip of metal beneath a doorway, barely noticed as you pass over it, or a grand atrium that you stop and marvel at on your way into the office. They can manifest as a change of materials or finishes, or of some parameter such as ceiling height. They might even be immaterial altogether, like the boundary between light and shadow. Thresholds transcend the physical to effect a psychological experience. They can be spatial or temporal or some combination of the two, but whatever form they take, all thresholds can be said to be mediators of our movement from one spatial status to another. Inside to outside, public to private, here to there. Too often our buildings relegate these changes to doors or openings that have little connection to the buildings they are a part of, and so our awareness of passage from space to space is diminished. This thesis explores ways to enrich the architecture of the threshold so that it doesn't merely recede to the bounds of our perception. / Master of Architecture / The term "threshold" often brings to mind a strip of material at the base of a doorway, but architecture considers thresholds more broadly as moments of movement or change. This thesis examines such moments in an original building design, proposing several threshold types and exploring their impact on occupants.

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