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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.
361

Quantification of Transhumeral Prosthetic Socket Residual Limb Interface Movement Using Motion Capture and a Slip Detection Sensor

Wernke, Matthew 08 January 2014 (has links)
Current literature focusing on the prosthetic socket is limited by measurement techniques and modeling assumptions, leading to a limited understanding of the forces and motions occurring between the residual limb and prosthesis and how they can be used to influence socket design and fitting. Prosthetic socket fitting and prescription would benefit from an elegant method for comparing socket designs. This dissertation focuses on the development and implementation of a 3D motion capture model and a Slip Detection Sensor to quantify rotations and translations at the prosthetic socket-residual limb interface. The 3D motion capture model defines the residual limb bone position inside the prosthetic socket which allows for measurement of the movement occurring at the prosthetic socket interface. The Slip Detection Sensor is an optoelectronic sensor embedded into the prosthetic socket wall to measure the amount of socket slip occurring between the socket wall and the residual limb skin surface. The motion capture model and Slip Detection Sensor were used to measure motion at the socket interface of transhumeral amputees during activities of daily living. Data were collected on six transhumeral amputees in the University of South Florida's (USF) motion analysis laboratory. One of the participants completed the collection procedures twice using two different suspension systems (pin locking versus no pin locking) within the same socket. An eight camera Vicon (Oxord, UK) motion capture system was used to collect kinematic data for each participant during the repetition of a series of range of motion (RoM) and activities of daily living (ADL). The RoM tasks included shoulder flexion/extension, shoulder abduction/adduction, shoulder rotation, and elbow flexion. The ADL tasks included a bilateral and unilateral lifting task at various weight increments, modified box and blocks test, folding a towel, and walk and carry a gallon jug of water. The impact of donning the prosthesis on the participant's RoM and the amount of socket movement during the ADL tasks was analyzed. The results show that the participant's shoulder RoM significantly decreased while wearing their prosthesis compared to when they were not wearing their prosthesis. The anterior-posterior tilt, medial-lateral tilt, and socket vertical translation were more directly correlated with the amount of residual limb movement than with the force acting on the prosthetic hand. Socket slip was most directly correlated with the force acting on the prosthetic hand. The results also show that the amount of translation was reduced when the pin locking suspension was used compared to when it wasn't for the individual participant who used both suspension systems within the same socket. The motion capture data were used to determine the amount of socket movement during activities of daily living while avoiding many of the limitations of other socket interface studies. The Slip Detection Sensor provided experimental data on the amount of slip occurring between the residual limb skin surface and socket wall. This method seems to be a useful tool for evaluating socket performance in terms of movement. Ultimately, socket interface movement data can be used to providing clinicians with quantitative results of a good socket fit to aid in the socket fitting and prescription process and incorporated into adjustable interfaces. Collection of data on more participants with various socket types is needed to make more general conclusions.
362

Evaluating Variance of the Model Credibility Index

Xiao, Yan 30 November 2007 (has links)
Model credibility index is defined to be a sample size under which the power of rejection equals 0.5. It applies goodness-of-fit testing thinking and uses a one-number summary statistic as an assessment tool in a false model world. The estimation of the model credibility index involves a bootstrap resampling technique. To assess the consistency of the estimator of model credibility index, we instead study the variance of the power achieved at a fixed sample size. An improved subsampling method is proposed to obtain an unbiased estimator of the variance of power. We present two examples to interpret the mechanics of building model credibility index and estimate its error in model selection. One example is two-way independent model by Pearson Chi-square test, and another example is multi-dimensional logistic regression model using likelihood ratio test.
363

Statistical tests based on N-distances / Statistinių hipotezių tikrinimas, naudojant N-metrikas

Bakšajev, Aleksej 09 April 2010 (has links)
The thesis is devoted to the application of a new class of probability metrics, N-distances, introduced by Klebanov (Klebanov, 2005; Zinger et al., 1989), to the problems of verification of the classical statistical hypotheses of goodness of fit, homogeneity, symmetry and independence. First of all a construction of statistics based on N metrics for testing mentioned hypotheses is proposed. Then the problem of determination of the critical region of the criteria is investigated. The main results of the thesis are connected with the asymptotic behavior of test statistics under the null and alternative hypotheses. In general case the limit null distribution of proposed in the thesis tests statistics is established in terms of the distribution of infinite quadratic form of random normal variables with coefficients dependent on eigenvalues and functions of a certain integral operator. It is proved that under the alternative hypothesis the test statistics are asymptotically normal. In case of parametric hypothesis of goodness of fit particular attention is devoted to normality and exponentiality criteria. For hypothesis of homogeneity a construction of multivariate distribution free two-sample test is proposed. Testing the hypothesis of uniformity on hypersphere in more detail S1 and S2 cases are investigated. In conclusion, a comparison of N-distance tests with some classical criteria is provided. For simple hypothesis of goodness of fit in univariate case as a measure for... [to full text] / Disertacinis darbas yra skirtas N-metrikų teorijos (Klebanov, 2005; Zinger et al., 1989) pritaikymui klasikinėms statistinėms suderinamumo, homogeniškumo, simetriškumo bei nepriklausomumo hipotezėms tikrinti. Darbo pradžioje pasiūlytas minėtų hipotezių testinių statistikų konstravimo būdas, naudojant N-metrikas. Toliau nagrinėjama problema susijusi su suformuotų kriterijų kritinės srities nustatymu. Pagrindiniai darbo rezultatai yra susiję su pasiūlytų kriterijaus statistikų asimptotiniu skirstiniu. Bendru atveju N-metrikos statistikų asimptotinis skirstinys esant nulinei hipotezei sutampa su Gauso atsitiktinių dydžių begalinės kvadratinės formos skirstiniu. Alternatyvos atveju testinių statistikų ribinis skirstinys yra normalusis. Sudėtinės suderinamumo hipotezės atveju išsamiau yra analizuojami normalumo ir ekponentiškumo kriterijai. Daugiamačiu atveju pasiūlyta konstrukcija, nepriklausanti nuo skirstinio homogeniškumo testo. Tikrinant tolygumo hipersferoje hipotezę detaliau yra nagrinėjami apskritimo ir sferos atvejai. Darbo pabaigoje lyginami pasiūlytos N-metrikos bei kai kurie klasikiniai kriterijai. Neparametrinės suderinamumo hipotezės vienamačiu atveju, kaip palyginimo priemonė, nagrinėjamas Bahaduro asimptotinis santykinis efektyvumas (Bahadur, 1960; Nikitin, 1995). Kartu su teoriniais rezultatais pasiūlytų N-metrikos tipo testų galingumas ištirtas, naudojant Monte-Karlo metodą. Be paprastos ir sudėtinės suderinamumo hipotezių yra analizuojami homogeniškumo testai... [toliau žr. visą tekstą]
364

Statistinių hipotezių tikrinimas, naudojant N-metrikas / Statistical tests based on N-distances

Bakšajev, Aleksej 09 April 2010 (has links)
Disertacinis darbas yra skirtas N-metrikų teorijos (Klebanov, 2005; Zinger et al., 1989) pritaikymui klasikinėms statistinėms suderinamumo, homogeniškumo, simetriškumo bei nepriklausomumo hipotezėms tikrinti. Darbo pradžioje pasiūlytas minėtų hipotezių testinių statistikų konstravimo būdas, naudojant N-metrikas. Toliau nagrinėjama problema susijusi su suformuotų kriterijų kritinės srities nustatymu. Pagrindiniai darbo rezultatai yra susiję su pasiūlytų kriterijaus statistikų asimptotiniu skirstiniu. Bendru atveju N-metrikos statistikų asimptotinis skirstinys esant nulinei hipotezei sutampa su Gauso atsitiktinių dydžių begalinės kvadratinės formos skirstiniu. Alternatyvos atveju testinių statistikų ribinis skirstinys yra normalusis. Sudėtinės suderinamumo hipotezės atveju išsamiau yra analizuojami normalumo ir ekponentiškumo kriterijai. Daugiamačiu atveju pasiūlyta konstrukcija, nepriklausanti nuo skirstinio homogeniškumo testo. Tikrinant tolygumo hipersferoje hipotezę detaliau yra nagrinėjami apskritimo ir sferos atvejai. Darbo pabaigoje lyginami pasiūlytos N-metrikos bei kai kurie klasikiniai kriterijai. Neparametrinės suderinamumo hipotezės vienamačiu atveju, kaip palyginimo priemonė, nagrinėjamas Bahaduro asimptotinis santykinis efektyvumas (Bahadur, 1960; Nikitin, 1995). Kartu su teoriniais rezultatais pasiūlytų N-metrikos tipo testų galingumas ištirtas, naudojant Monte-Karlo metodą. Be paprastos ir sudėtinės suderinamumo hipotezių yra analizuojami homogeniškumo testai... [toliau žr. visą tekstą] / The thesis is devoted to the application of a new class of probability metrics, N-distances, introduced by Klebanov (Klebanov, 2005; Zinger et al., 1989), to the problems of verification of the classical statistical hypotheses of goodness of fit, homogeneity, symmetry and independence. First of all a construction of statistics based on N-metrics for testing mentioned hypotheses is proposed. Then the problem of determination of the critical region of the criteria is investigated. The main results of the thesis are connected with the asymptotic behavior of test statistics under the null and alternative hypotheses. In general case the limit null distribution of proposed in the thesis tests statistics is established in terms of the distribution of infinite quadratic form of random normal variables with coefficients dependent on eigenvalues and functions of a certain integral operator. It is proved that under the alternative hypothesis the test statistics are asymptotically normal. In case of parametric hypothesis of goodness of fit particular attention is devoted to normality and exponentiality criteria. For hypothesis of homogeneity a construction of multivariate distribution-free two-sample test is proposed. Testing the hypothesis of uniformity on hypersphere in more detail S1 and S2 cases are investigated. In conclusion, a comparison of N-distance tests with some classical criteria is provided. For simple hypothesis of goodness of fit in univariate case as a measure for... [to full text]
365

Energy Substitution Rates and Energy Policy Analysis on Nova Scotia Dairy Farms

Biggs, Jaclyn N 11 December 2012 (has links)
This paper analyzes energy substitution rates on dairy farms in Nova Scotia (NS), Canada. A transcendental logarithmic cost function is used to find the elasticities of substitution which are utilized to determine the substitutability of total farm energy and to determine feasible renewable energy (RE) technologies. Wind turbines are found to be the only feasible RE technology for dairy farms within the region, at this time. A review of on-farm RE production and the associated feed-in tariff (FIT) policies in Germany, USA, Canada, Denmark and the Netherlands are examined. The NS FIT policy is used as a case study to assess the effect policies may have on wind turbine implementation by NS farms. Several scenarios are developed based on the existing policy structure to provide a critical review of the policy and to identify methods to provide an increase in the implementation of wind turbines on NS dairy farms.
366

Detecting Inaccurate Response Patterns in Korean Military Personality Inventory: An Application of Item Response Theory

Hong, Seunghwa 16 December 2013 (has links)
There are concerns regarding the risk of the inaccurate responses in the personality data. The inaccurate responses negatively affect in the individual selection contexts. Especially, in the military context, the personality score including inaccurate responses results in the selection of inappropriate personnel or allows enlistment dodgers to avoid their military duty. This study conducted IRT-based person-fit analysis with the dichotomous military dataset in the Korean Military Personality Inventory. In order for that, 2PL model was applied for the data and person-fit index l_(z) was used to detect aberrant respondents. Based on l_(z) values of each respondent, potentially inaccurate respondents was identified. In diagnosing possible sources of aberrant response patterns, PRCs was assessed. This study with the military empirical data shows that person-fit analysis using l_(z) is applicable and practical method for detecting inaccurate response patterns in the personnel selection contexts based on the personality measurement.
367

Maximum spacing methods and limit theorems for statistics based on spacings

Ekström, Magnus January 1997 (has links)
The maximum spacing (MSP) method, introduced by Cheng and Amin (1983) and independently by Ranneby (1984), is a general estimation method for continuous univariate distributions. The MSP method, which is closely related to the maximum likelihood (ML) method, can be derived from an approximation based on simple spacings of the Kullback-Leibler information. It is known to give consistent and asymptotically efficient estimates under general conditions and works also in situations where the ML method fails, e.g. for the three parameter Weibull model. In this thesis it is proved under general conditions that MSP estimates of parameters in the Euclidian metric are strongly consistent. The ideas behind the MSP method are extended and a class of estimation methods is introduced. These methods, called generalized MSP methods, are derived from approxima­tions based on sum-functions of rath order spacings of certain information mea­sures, i.e. the ^-divergences introduced by Csiszår (1963). It is shown under general conditions that generalized MSP methods give consistent estimates. In particular, it is proved that generalized MSP methods give L1 consistent esti­mates in any family of distributions with unimodal densities, without any further conditions on the distributions. Other properties such as distributional robust­ness are also discussed. Several limit theorems for sum-functions of rath order spacings are given, for ra fixed as well as for the case when ra is allowed to in­crease to infinity with the sample size. These results provide a strongly consistent nonparametric estimator of entropy, as well as a characterization of the uniform distribution. Further, it is shown that Cressie's (1976) goodness of fit test is strongly consistent against all continuous alternatives. / digitalisering@umu
368

How consumers judge brands endorsed by corporations : a process-based explanation

Ibraheem, Khaled Assad January 2012 (has links)
Corporations follow different strategies to leverage their existing brands. One of these is brand extension, which is the extension of an existing brand to a new product category. In this strategy, corporations have two alternatives, one of which is the family brand extension. Here, the new product is introduced under the corporate name along with the extension’s category name (e.g. Sony mobile, Nestlé mineral water, and Gillette shampoo). The second alternative is the brand endorsement. In this alternative, the extension is given a new name. Moreover, the corporation’s name is presented as the endorser in the extension brand structure and communications (e.g. Scandic by Hiliton, Courtyard by Marriott). However, the focus will be on the extension brand name, rather than the corporate name. The endorser’s main role is to provide credibility and substance to the endorsed brand, while maintaining the endorsed brand’s freedom to establish its unique associations and personality. It is well-known that, in the family brand extension, the perceived fit between the parent brand and the extension product category moderates consumers’ judgement of the extension (i.e. the new product which is introduced under the parent name). However, widely-diversified corporations (e.g. Nestlé, Unilever) often endorse their products to leverage their corporate credibility. The proliferation of using a corporate name to endorse products in the case of corporations with diversified product portfolios puts the importance of the fit on the corporate endorser, and the endorsed product brand under scrutiny. Specifically, it raises the following questions: to what extent is the perceived fit between the corporate brand endorser and the endorsed brand really important in an endorsement context? What is the relative importance of fit and endorser credibility in an endorsement context, and why? In the current research, it is proposed that both corporate credibility and fit affect consumers’ judgement in an endorsement context. However, the endorser credibility is more important. It is also proposed that corporate credibility is more important than fit because it is more diagnostic, which makes the endorser credibility more recallable for the consumer. The current research results have shown that, when consumers can easily recall information related to the endorser credibility and the fit between the endorser and the endorsed brand, both endorser credibility and fit has an effect on the endorsed brand. However, endorser credibility has a stronger effect on the endorsed brand judgement than fit. Moreover, the results have shown that fit moderates the effect of corporate credibility only when the endorser credibility is high. When consumers have difficulty recalling information, fit does not moderate the effect of the endorser credibility on the endorsed brand. The current research findings have been obtained by conducting two experiments. In Experiment One, corporate credibility and perceived fit were manipulated in an endorsement context. Consumer judgement of the endorsed brand was measured by the perceived quality and purchase intention. Experiment Two was conducted to study the impact of the information accessibility on the effect of the endorser credibility and fit on the endorsed brand judgement. Endorser credibility, fit and information accessibility were manipulated in an endorsement context. Perceived quality and purchase intention of the endorsed brand were also used to measure the consumers’ judgement of the endorsed brand.
369

Dual-response approach to work stress: An investigation of organisational stressors, individual moderators and wellbeing outcomes.

Walls, Frances Grace January 2012 (has links)
This study demonstrates the complex place stress has in the workplace by investigating both positive (eustress) and negative (distress) stress responses. An international sample of 140 individuals was recruited from various industries and organisational levels and these individuals participated in a confidential online survey. A moderated mediation model was proposed in which organisational stressors (person-job fit and role overload) influenced employee affective wellbeing directly and indirectly through stress responses, moderated by individual factors (work-family conflict and self-efficacy). Person-job fit influenced eustress which had positive effects on employee affective wellbeing. Role overload influenced distress which negatively impacted affective wellbeing. Self-efficacy moderated these relationships, with high levels increasing stress responses both negative and positive. Work-family conflict moderated relationships by reducing the positive effect of eustress and increasing the negative effect of distress. The findings not only advance current knowledge but have implications for organisational stress management practices.
370

Untersuchung zur Passgenauigkeit CAD/CAM-gefertigter Kronengerüste in Abhängigkeit von den verwendeten Materialien / Marginal fit analysis of CAD/CAM fabricated crown frameworks depending on the used materials

Gronau, Karin Christine 30 June 2015 (has links)
No description available.

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