• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3617
  • 1739
  • 849
  • 356
  • 356
  • 267
  • 215
  • 189
  • 183
  • 76
  • 76
  • 60
  • 52
  • 49
  • 43
  • Tagged with
  • 9390
  • 1244
  • 945
  • 773
  • 658
  • 633
  • 612
  • 594
  • 538
  • 441
  • 428
  • 421
  • 406
  • 395
  • 380
  • 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.
51

On the convergence rate of complete convergence

Tseng, Tzu-Hui 12 June 2003 (has links)
egin{abstract} hspace{1cm}Let $X_{1}$, $X_{2}$, $cdots$, $X_{n}$ be a sequence of independent indentically distributed random variables ( i. i. d.) and $displaystyle S_{n}=X_{1}+X_{2} +cdots X_{n}$. Denote $displaystylelambda(varepsilon)=sum^{infty}_{n=1}P{left|S_{n} ight|geq nvarepsilon}$, the convergence rate of $displaystylelambda(varepsilon)$ is studied. O.I. Klesov proved that if $E|X_{1}|^{3}$ exists, then $displaystyle varepsilon^{frac{3}{2}}(lambda(varepsilon)-frac{sigma^{2}}{varepsilon^{2}}) ightarrow 0$. In this thesis, we show that if $E|X_{1}|^{2+delta}<infty$ for some $displaystyle deltain(frac{sqrt{7}-1}{3},1]$, the result of O.I. Klesov still holds. end{abstract}
52

Catalytic studies of supported Pd-Au catalysts

Boopalachandran, Praveenkumar 16 August 2006 (has links)
Although Pd-Au high-surface area catalysts are used in industry to improve activity and selectivity, a thorough understanding of the nature of these enhancements is lacking. A molecular-level understanding of catalytic reactions under actual reaction conditions is the ultimate goal. This thesis is mainly focused on the application of Pd-Au supported catalysts for vinyl acetate synthesis and CO oxidation reactions using highsurface area catalysts. We have attempted to improve the conventional Pd-Au based catalyst by synthesizing novel acetate-based and polymer-based catalysts. The corresponding catalytic reactivity and selectivity were measured and compared to conventional Pd-Au based catalyst systems. Subsequent characterization was performed using characterization techniques, such as, X-ray diffraction (XRD) and transmission electron microscopy (TEM). From our bimetallic catalytic studies, it was evident that the addition of Au to Pd leads to increased reactivity and selectivity. This surface modification is an important factor in the altered reaction kinetics for vinyl acetate (VA) synthesis and CO oxidation reactions. Promoted and unpromoted Pd-Au/SiO2/K+ catalyst were used for VA synthesis and the effect of pre-adsorbed O2, acetic acid and the role of oxygen were explored. The VA reaction rate of novel acetate-based Pd-Au/SiO2 catalyst was 3.5 times higher than conventional Pd-Au catalysts. Also, 100% selectivity was obtained for acetate-based Pd-Au/SiO2 at 130 oC and the VA formation rate was comparable to that of conventional Pd-Au catalysts. Therefore, the acetate-based Pd-Au/SiO2 catalyst seems very promising and can be explored further. Also, Pd(1):Au(4)/SiO2 catalysts demonstrate 100% CO conversion at much lower temperatures (90 oC) compared with other Pd-Au based catalysts. Furthermore, we were successful in obtaining sufficient CO oxidation activity with increased metal loading (5 wt%) and these catalysts did not deactivate under above-ambient reaction temperature conditions, which make 1:4 Pd- Au/SiO2 catalyst a good candidate for further exploration in CO oxidation reactions.
53

Modeling of strain rate effects on clay in simple shear

Jung, Byoung Chan 16 August 2006 (has links)
The objective of this research is the development of a new constitutive model to describe the behavior of cohesive soils under time dependent loading. In the work presented here, the modified SIMPLE DSS model is expanded to account for the effects of strain rate on clays in simple shear conditions. The response of clay soils is highly dependent on the rate of strain for both effective stress path and stress-strain behavior. The undrained shear strength is strongly influenced by strain rate both in monotonic and cyclic simple shear tests. Nevertheless, the few available experimental results cover a very limited range of loading conditions and rates. The existing literature established that the soil response display a unique relationship between shear strength and log scale of strain rate. To include the effects of strain rate, the modified simple effective stress model starts with two assumptions: (1) a specific shear strength corresponds to a specific strain rate in a unique relation; and (2) the effect of strain rate does not change the failure envelope. The proposed model is developed from the original SIMPLE DSS model, based on an effective stress formulation in a reduced stress space, and utilizing concepts related to the framework of bounding surface plasticity. The proposed model evaluationwas carried out comparing model simulations with results of simple shear tests on Boston Blue Clay and San Francisco Young Bay Mud. The model capability is useful especially in strain rate dependent responses for both monotonic and cyclic behavior, including irregular loading and step-changed condition. It was found that undrained shear strength in simple shear is directly related to strain rate effects and the responses in cyclic test show the more rate dependent behavior than those in monotonic test. The proposed model is able to predict the increase in undrained shear strength for higher strain rate.
54

Detecting Apnea and Hypopnea Events by using Peaks of Flow Rate Signals

Huang, Ren-tsung 18 July 2008 (has links)
This study uses flow rate and blood oxygen saturation signals to detect apnea and hypopnea events. The detection process consist two phases, by using the peaks of flow rate signals to determine respiratory cycles, the first phase uses seven flow rate feature to distinguish normal and abnormal respiratory events. To reduce the false detection rate, by appending two additional blood oxygen saturation variables into the feature set, the second phase tries to filter out some falsely detected events made in the first phase. Experimental results show that the proposed approach achieves detection accuracy is 81%. The corresponding false detection rate is 67%. One reason for the high false detection rate is that many normal respiratory events has lower amplitude airflow pattern. To resolve such a difficulty, additional physiological signals may be required.
55

none

Yu, Ling-yan 29 August 2009 (has links)
Abstract Since 2008, the overall unemployment rate has been rising sharply, and the overall unemployment and economic problems have gradually emerged. The unemployment rate in areas of Kaohsiung City, Kaohsiung County, and Pingtung County is higher than the standard of the whole Taiwan area, and the industrial development in areas of Kaohsiung City, Kaohsiung County, and Pingtung County starts to change. Under this circumstance, enterprises and unemployed persons attach more importance to Taiwan government's vocational training policies. Vocational training has always been the government's main long-term human resources policy. Therefore, this study is trying to discuss how to cultivate the manpower needed by enterprises and promote unemployed persons to re-enter the job market through vocational training, promote the overall social stability and activate economy, and probe into the pre-service training items for public vocational training in order to attain the goals and purposes of vocational training. Employment security is one of the major policies of Taiwan government, and vocational training and employment services are the greatest demands for people toward employment security. Although the policy goals of vocational training are quite clear, the actual practice still leaves room for improvement. The contents of this study include: analysis of difficulties encountered by people in areas of Kaohsiung City, Kaohsiung County, and Pingtung County; planning for vocational training courses administered by the government; and direction of enterprises¡¦ demand for talents. This study clarifies the demands of the existing enterprises and people for professional vocational training from the angle of the needs of enterprises, market and unemployed persons, as well as supply differences, and further submits concrete suggestions for improving employment ability and meeting the needs of enterprises for talents. From this study, it is found that there is a gap between enterprises¡¦ demand for manpower and the existing vocational training items. Consequently, the employment ability of the unemployed people can¡¦t be solved effectively. The main factor lies in the fact that the vocational training units fail to control complete and sufficient information about the job market. So, the vocational training units are suggested to understand the talent gap of enterprises first before they develop vocational training courses as the pre-service training projects for unemployed persons in the future, so as to create a win-win-win situation for enterprises, unemployed persons, and vocational training units. Keywords¡Gunemployment rate, vocational training
56

Kyste hydatique splenique rompu à propos d'un cas survenu au S.A.U.d'Epinal /

Giraud, Isabelle. Boissel, Patrick. January 2003 (has links) (PDF)
Reproduction de : Thèse d'exercice : Médecine : Nancy 1 : 2003. / Titre provenant de l'écran-titre.
57

Return on capital employed at Naval Dental Center Gulf Coast /

Yonkers, Michael A. Flis, Marek. January 2003 (has links) (PDF)
Thesis (M.B.A.)--Naval Postgraduate School, December 2003. / "MBA professional report"--Cover. Thesis advisor(s): Joseph G. San Miguel, Don E. Summers. Includes bibliographical references (p. 35). Also available online.
58

Discrepancy between training, competition and laboratory measures of maximum heart rate in NCAA division 2 distance runners

Semin, K, Stahlnecker, AC, Heelan, K, Brown, GA, Shaw, BS, Shaw, I 21 November 2008 (has links)
A percentage of either measured or predicted maximum heart rate is commonly used to prescribe and measure exercise intensity. However, maximum heart rate in athletes may be greater during competition or training than during laboratory exercise testing. Thus, the aim of the present investigation was to determine if endurance-trained runners train and compete at or above laboratory measures of ‘maximum’ heart rate. Maximum heart rates were measured utilising a treadmill graded exercise test (GXT) in a laboratory setting using 10 female and 10 male National Collegiate Athletic Association (NCAA) division 2 cross-country and distance event track athletes. Maximum training and competition heart rates were measured during a highintensity interval training day (TR HR) and during competition (COMP HR) at an NCAA meet. TR HR (207 ± 5.0 b·min-1; means ± SEM) and COMP HR (206 ± 4 b·min-1) were significantly (p < 0.05) higher than maximum heart rates obtained during the GXT (194 ± 2 b·min-1). The heart rate at the ventilatory threshold measured in the laboratory occurred at 83.3 ± 2.5% of the heart rate at VO2 max with no differences between the men and women. However, the heart rate at the ventilatory threshold measured in the laboratory was only 77% of the maximal COMP HR or TR HR. In order to optimize traininginduced adaptation, training intensity for NCAA division 2 distance event runners should not be based on laboratory assessment of maximum heart rate, but instead on maximum heart rate obtained either during training or during competition.
59

A Study of the Cure Rate Model with Case Weights and Time-Dependent Weights

Datta, Aditi 14 March 2013 (has links)
The proportional hazard (PH) cure rate model and the marginal structural Cox model (MSCM) are two broad areas used in analysing survival models with longitudinal data. Cure rate models were introduced to deal with survival models in the presence of a cure fraction and marginal structural models were introduced to adjust for time- ependent confounders through time-dependent weighting in longitudinal studies. However, few studies have tried to combine these two areas in building cure rate models in the presence of time-dependent covariates and time-dependent confounders. This thesis proposes an extension of the maximum likelihood estimation procedure for the PH cure rate model by incorporating (i) case weights, (ii) time-dependent covariates, and (iii) time-dependent weights in the presence of time-dependent covariates and time-dependent confounders into the model. Further, this thesis compares the performance of the PH cure rate model with case weights to the standard unweighted PH cure rate model through simulation studies. Results of these studies suggest that adding case weights in the PH cure rate model improves the estimation of the latency parameter when the sample size is relatively small.
60

Adjusting route charges to increase profit

Andersson, Markus, Blomdahl, Rikard January 2013 (has links)
Route charges are fees that airlines pay in order to utilize the Air Navigation Services (ANS) of a European state. The fee is based on three values; the weight of the aircraft, the length of the flight, and the state’s specific unit rate. The unit rate of each state is in turn based on the forecasted costs of providing ANS for that state and the amount of traffic forecasted for the year to come. This makes for different unit rates for different states, which leads to different costs for flying different routes in the European airspace. A state having costs that are increasing faster than the amount of traffic is increasing will lead to a higher unit rate. A higher unit rate may lead to airlines avoiding the state’s airspace due to higher costs, thus accounting for even less traffic and an increase in unit rate. This thesis examines the relationship between unit rate and amount of traffic, and specifically tries to find out how much the unit rate affects the traffic count. This has been done by reading previous papers on the subject, and creating a model to easily present facts found. The result of the thesis suggests that states actually profits more by increasing the unit rate rather than actively trying to reduce it. This contradicts the idea of lowering prices always being a good thing. There is a limit to how much the unit rate can be increases however, at which all traffic will choose to circumnavigate the airspace. Finding a good balance between traffic lost and unit rate increased is suggested as the best way to go.

Page generated in 0.0385 seconds