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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.
81

On Perceived Exertion and its Measurement

Borg, Elisabet January 2007 (has links)
<p>The general aim of the thesis is to answer questions on general and differential aspects of perceived exertion and on the measurement of its intensity variation. Overall perceived exertion is commonly treated as a unidemensional construct. This thesis also explores its multidimensional character. Four empirical studies are summarized (Study I-IV). Psychophysical power functions of perceived exertion obtained with the new improved Borg CR100 (centiMax) scale were found to be consistent with results obtained with absolute magnitude estimation, and with the classical Borg CR10 and RPE scales. Women gave significantly higher perceived exertion scale values than men for the same levels of workload on a bicycle ergometer. This agrees with the fact that they were physically less strong than men. With regard to the measurement of “absolute” levels of intensity, RPE- and CR-scale values were validated by physiological measurements of heart rate and blood lactate. Predicted values of maximal individual performance obtained from psychophysical functions agreed well with actual maximal performance on the bicycle ergometer. This confirms the validity of the RPE and CR scales for measuring perceptual intensity and their value for interindividual comparisons. To study the multidimensional character of perceived exertion, 18 symptoms were measured with a CR scale: in a questionnaire, and in bicycle ergometer work tests. Five factors were extracted for the questionnaire: (1) Muscles and joints; (2) Perceived exertion; (3) Annoyance/lack of motivation; (4) Head/stomach symptoms; and (5) Cardiopulmonary symptoms. Four factors were extracted for the bicycle max test: (1) Physical distress; (2) Central perceived exertion; (3) Annoyance/lack of motivation; (4) Local perceived exertion. The questionnaire is suggested for clinical use to let patients express a variety of symptoms. The thesis also resulted in improvements of the Borg CR100 scale. An extended use of the scale is recommended.</p>
82

A comparative study of 2 CAD-integrated FE-programs using the linear static analysis

Amin, Handren January 2009 (has links)
<p>This Master’s thesis is summery of a comparative study of 2 commercial CAD-integrated</p><p>FE-programs. These FE-programs were CATIA v5 and ABAQUS 6.3-7. The primary</p><p>objective of this study is to investigate the basic FEA capabilities of CATIA and</p><p>ABAQUS 6.7-3 in performing the linear static analysis and to identify whether there are</p><p>any differences and similarities between results the both Finite Element FE codes give.</p><p>The overall research question in the present thesis is: Do different FE programs, here</p><p>CATIA and ABAQUS, give the same results for FE analysis giving the same models if</p><p>subjected to the same boundary conditions? This research seeks to achieve its aims</p><p>through making a comparative qualitative study. Certain pre-selections were performed in</p><p>advance of conducting Finite element analysis and the comparison process to ensure that</p><p>results would reflect only the most relevant and meaningful differences and similarities</p><p>between the both FE-codes. Five different 3D solid models have been selected to perform</p><p>linear static Finite element analysis on. All these models (case studies) are created in</p><p>CATIA V5 and the linear static analysis conducted on using FE-codes CATIA v5 and</p><p>ABAQUS 6.7-3. Three static responses (results) of the linear static analysis have been</p><p>adopted as criteria for comparisons purposes. These criteria were: (1) displacements, (2)</p><p>Von Mises stress, and (3) principal stress. The results of comparisons showed that there is</p><p>a very good agreement in most cases and small gap between in a few cases. Results of</p><p>this study demonstrate that the both FE-programs CATIA v5 and ABAQUS 6.7-3 have</p><p>good capabilities to perform FE-analysis and they give very near results. Reason behind</p><p>differences is that each of them uses a different algorithm for solving problems. The final</p><p>answer for the research question is given with valuable recommendations for future work</p><p>in the scope of this research.</p>
83

On Perceived Exertion and its Measurement

Borg, Elisabet January 2007 (has links)
The general aim of the thesis is to answer questions on general and differential aspects of perceived exertion and on the measurement of its intensity variation. Overall perceived exertion is commonly treated as a unidemensional construct. This thesis also explores its multidimensional character. Four empirical studies are summarized (Study I-IV). Psychophysical power functions of perceived exertion obtained with the new improved Borg CR100 (centiMax) scale were found to be consistent with results obtained with absolute magnitude estimation, and with the classical Borg CR10 and RPE scales. Women gave significantly higher perceived exertion scale values than men for the same levels of workload on a bicycle ergometer. This agrees with the fact that they were physically less strong than men. With regard to the measurement of “absolute” levels of intensity, RPE- and CR-scale values were validated by physiological measurements of heart rate and blood lactate. Predicted values of maximal individual performance obtained from psychophysical functions agreed well with actual maximal performance on the bicycle ergometer. This confirms the validity of the RPE and CR scales for measuring perceptual intensity and their value for interindividual comparisons. To study the multidimensional character of perceived exertion, 18 symptoms were measured with a CR scale: in a questionnaire, and in bicycle ergometer work tests. Five factors were extracted for the questionnaire: (1) Muscles and joints; (2) Perceived exertion; (3) Annoyance/lack of motivation; (4) Head/stomach symptoms; and (5) Cardiopulmonary symptoms. Four factors were extracted for the bicycle max test: (1) Physical distress; (2) Central perceived exertion; (3) Annoyance/lack of motivation; (4) Local perceived exertion. The questionnaire is suggested for clinical use to let patients express a variety of symptoms. The thesis also resulted in improvements of the Borg CR100 scale. An extended use of the scale is recommended.
84

A comparative study of 2 CAD-integrated FE-programs using the linear static analysis

Amin, Handren January 2009 (has links)
This Master’s thesis is summery of a comparative study of 2 commercial CAD-integrated FE-programs. These FE-programs were CATIA v5 and ABAQUS 6.3-7. The primary objective of this study is to investigate the basic FEA capabilities of CATIA and ABAQUS 6.7-3 in performing the linear static analysis and to identify whether there are any differences and similarities between results the both Finite Element FE codes give. The overall research question in the present thesis is: Do different FE programs, here CATIA and ABAQUS, give the same results for FE analysis giving the same models if subjected to the same boundary conditions? This research seeks to achieve its aims through making a comparative qualitative study. Certain pre-selections were performed in advance of conducting Finite element analysis and the comparison process to ensure that results would reflect only the most relevant and meaningful differences and similarities between the both FE-codes. Five different 3D solid models have been selected to perform linear static Finite element analysis on. All these models (case studies) are created in CATIA V5 and the linear static analysis conducted on using FE-codes CATIA v5 and ABAQUS 6.7-3. Three static responses (results) of the linear static analysis have been adopted as criteria for comparisons purposes. These criteria were: (1) displacements, (2) Von Mises stress, and (3) principal stress. The results of comparisons showed that there is a very good agreement in most cases and small gap between in a few cases. Results of this study demonstrate that the both FE-programs CATIA v5 and ABAQUS 6.7-3 have good capabilities to perform FE-analysis and they give very near results. Reason behind differences is that each of them uses a different algorithm for solving problems. The final answer for the research question is given with valuable recommendations for future work in the scope of this research.
85

Psychometric functions of clear and conversational speech for young normal hearing listeners in noise

Smart, Jane 01 June 2007 (has links)
Clear speech is a form of communication that talkers naturally use when speaking in difficult listening conditions or with a person who has a hearing loss. Clear speech, on average, provides listeners with hearing impairments an intelligibility benefit of 17 percentage points (Picheny, Durlach, & Braida, 1985) over conversational speech. In addition, it provides increased intelligibility in various listening conditions (Krause & Braida, 2003, among others), with different stimuli (Bradlow & Bent, 2002; Gagne, Rochette, & Charest, 2002; Helfer, 1997, among others) and across listener populations (Bradlow, Kraus, & Hayes, 2003, among others). Recently, researchers have attempted to compare their findings with clear and conversational speech, at slow and normal rates, with results from other investigators' studies in an effort to determine the relative benefits of clear speech across populations and environments. However, relative intelligibility benefits are difficult to determine unless baseline performance levels can be equated, suggesting that listener psychometric functions with clear speech are needed. The purpose of this study was to determine how speech intelligibility, as measured by percentage key words correct in nonsense sentences by young adults, varies with changes in speaking condition, talker and signal-to-noise ratio (SNR). Forty young, normal hearing adults were presented with grammatically correct nonsense sentences at five SNRs. Each listener heard a total of 800 sentences in four speaking conditions: clear and conversational styles, at slow and normal rates (i.e., clear/slow, clear/normal, conversational/slow, and conversational/normal). Overall results indicate clear/slow and conversational/slow were the most intelligible conditions, followed by clear/normal and then conversational/normal conditions. Moreover, the average intelligibility benefit for clear/slow, clear/normal and conversational/slow conditions (relative to conversational/normal) was maintained across an SNR range of -4 to 0 dB in the middle, or linear, portion of the psychometric function. However, when results are examined by talker, differences are observed in the benefit provided by each condition and in how the benefit varies across noise levels. In order to counteract talker variability, research with a larger number of talkers is recommended for future studies.
86

Fitting paired comparison models in R

Hatzinger, Reinhold, Francis, Brian January 2004 (has links) (PDF)
Paired comparison models in loglinear form are generalised linear models and can be fitted using the IWLS algorithm. Unfortunately, the design matrices can become very large and thus a method is needed to reduce computational load (relating to both space and time). This paper discusses an algorithm for fitting loglinear paired comparison models in the presence of many nuisance parameters which is based on partition rules for symmetric matrices and takes advantage of the special structure of the design matrix in Poisson loglinear models. The algorithm is implemented as an R function. Some simple examples illustrate its use for fitting both paired comparison models and (multinomial) logit models. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics
87

Statistical Analysis of Operational Data for Manufacturing System Performance Improvement

Wang, Zhenrui January 2013 (has links)
The performance of a manufacturing system relies on its four types of elements: operators, machines, computer system and material handling system. To ensure the performance of these elements, operational data containing various aspects of information are collected for monitoring and analysis. This dissertation focuses on the operator performance evaluation and machine failure prediction. The proposed research work is motivated by the following challenges in analyzing operational data. (i) the complex relationship between the variables, (ii) the implicit information important to failure prediction, and (iii) data with outliers, missing and erroneous measurements. To overcome these challenges, the following research has been conducted. To compare operator performance, a methodology combining regression modeling and multiple comparisons technique is proposed. The regression model quantifies and removes the complex effects of other impacting factors on the operator performance. A robust zero-inflated Poisson (ZIP) model is developed to reduce the impacts of the excessive zeros and outliers in the performance metric, i.e. the number of defects (NoD), on regression analysis. The model residuals are plotted in non-parametric statistical charts for performance comparison. The estimated model coefficients are also used to identify under-performing machines. To detect temporal patterns from operational data sequence, an algorithm is proposed for detecting interval-based asynchronous periodic patterns (APP). The algorithm effectively and efficiently detects pattern through a modified clustering and a convolution-based template matching method. To predict machine failures based on the covariates with erroneous measurements, a new method is proposed for statistical inference of proportional hazard model under a mixture of classical and Berkson errors. The method estimates the model coefficients with an expectation-maximization (EM) algorithm with expectation step achieved by Monte Carlo simulation. The model estimated with the proposed method will improve the accuracy of the inference on machine failure probability. The research work presented in this dissertation provides a package of solutions to improve manufacturing system performance. The effectiveness and efficiency of the proposed methodologies have been demonstrated and justified with both numerical simulations and real-world case studies.
88

Noise spectra comparison among wind turbinesand its implications to human perception.

Boti, Ismael January 2014 (has links)
The noise coming from wind power development can be an environmental impact forthe surrounding communities. It is well known that the main wind turbine noise iscaused by the movement of the turbine wings through the air. However, there areuncertainties about the importance of machinery sounds and possible variations amongwind turbines. A high resolution acquisition system was used to perform a fieldexperiment comparison of the noise spectra from some wind turbines at Laholm(Sweden). The results have shown different band spectra peaks associated to machinerysounds among wind turbines from the same model and also from those of differentmanufactures. Maintenance conditions of these wind turbines could explain thedifferences in intensity and frequency locations of the band spectra peaks found. Inorder to know the importance for human audition of these peaks, listening test or doseresponsestudies would be needed to provide relevant information in this regard. Themethodology developed in this study is suggested to be useful for identifying certainmachinery failures which could corrupt the noise sounds emitted at certain wind turbinelocations.
89

”Jag känner att vi är tvillingar, men jag måste få vara mig själv.” : En kvalitativ studie om enäggstvillingars upplevelser kring sin identiteti sin sociala miljö.

Öman, Cecilia, Ladan, Antonija January 2014 (has links)
Denna studie understryker den sociala miljöns betydelse för enäggstvillingars identitetsskapande. Hur utvecklas identiteten hos två genetiskt identiska individer som växer upp i samma miljö? Undersökningen bygger på kvalitativa intervjuer med tio enäggstvillingar, som även vill ge en inblick i hur enäggstvillingar upplever sin relation till sin tvilling och hur de upplever att de uppfattas av den sociala omgivningen. I vår teoretiska referensram har vi använt oss av diverse identitetsteorier som betonar interpersonella- och grupprocesser, Cooleys teori om spegeljaget samt den sociala jämförelseteorin som presenteras av Festinger. I resultatet framgick det hur enäggstvillingars identitet uppfattas i förhållande till sin tvilling, där omgivningen hade en betydande roll i enäggstvillingarnas identitetsskapande men även hur jämförelser direkt påverkade den egna självkänslan. Vi vill även konstatera att samtliga enäggstvillingar delade upplevelsen av trygghet och gemenskap i relationen till sin tvilling. / This study emphasizes the social environment to identical twins identity. How does the identity of two genetically identical individuals who grow up in the same environment develop? The study is based on qualitative interviews with ten identical twins, who also want to give a glimpse of how identical twins experience their relationship with their twin and how they experience they are perceived by the social environment. We have been using various identity theories that emphasize interpersonal and group processes in our theoretical framework, also Cooley's theory of the looking glass self and the social comparison theory presented by Festinger. The result showed how identical twins identity was perceived in relation to its twin, where the social environment had a significant role for identical twins identity but also how comparisons directly affected their self-esteem. We would also note that all identical twins shared the experience of safety and fellowship in relation to its twin.
90

Multi-purpose multi-way data analysis

Ebrahimi Mohammadi, Diako, Chemistry, Faculty of Science, UNSW January 2007 (has links)
In this dissertation, application of multi-way analysis is extended into new areas of environmental chemistry, microbiology, electrochemistry and organometallic chemistry. Additionally new practical aspects of some of the multi-way analysis methods are discussed. Parallel Factor Analysis Two (PARAFAC2) is used to classify a wide range of weathered petroleum oils using GC-MS data. Various chemical and data analysis issues exist in the current methods of oil spill analysis are discussed and the proposed method is demonstrated to have potential to be employed in identification of source of oil spills. Two important practical aspects of PARAFAC2 are exploited to deal with chromatographic shifts and non-diagnostic peaks.GEneralized Multiplicative ANalysis Of VAriance (GEMANOVA) is applied to assess the bactericidal activity of new natural antibacterial extracts on three species of bacteria in different structure and oxidation forms and different concentrations. In this work while the applicability of traditional ANOVA is restricted due to the high interaction amongst the factors, GEMANOVA is shown to return robust and easily interpretable models which conform to the actual structure of the data. Peptide-modified electrochemical sensors are used to determine three metal cations of Cu2+, Cd2+ and Pb2+ simultaneously. Two sets of experiments are performed using a four-electrode system returning a three-way array of size (sample ?? current ?? electrode) and a single electrode resulting in a two-way data set of size (sample ?? current). The data of former is modeled by N-PLS and that latter using PLS. Despite the presence of highly overlapped voltammograms and several sources of non-linearity N-PLS returns reasonable models while PLS fails. An intramolecular hydroamination reaction is catalyzed by several organometallic catalysts to identify the most effective catalysts. The reaction of starting material in the presence of 72 different catalysts is monitored by UV-Vis at two time points, before and after heating the mixtures in an oven. PARAFAC is applied to the three-way data set of (sample ?? wavelength ?? time) to resolve the overlapped UV-Vis peaks and to identify the effective catalysts using the estimated relative concentration of product (loadings plot of the sample mode).

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