• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1154
  • 824
  • 181
  • 129
  • 114
  • 76
  • 40
  • 30
  • 26
  • 20
  • 18
  • 13
  • 11
  • 10
  • 9
  • Tagged with
  • 2999
  • 924
  • 347
  • 277
  • 272
  • 226
  • 154
  • 153
  • 139
  • 137
  • 134
  • 123
  • 121
  • 113
  • 106
  • 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.
601

Development Of A Direct Type Road Roughness Evaluation System

Hu, Fengxuan 01 April 2004 (has links)
Roughness is an important indicator of pavement riding comfort and safety. It is a condition indicator that should be carefully considered when evaluating primary pavements. At the same time, the use of roughness measurements plays a critical role in the pavement management system. There are many devices used for roughness evaluation. The major tools used for road roughness quantify are the road profilers. In the thesis research, in order to obtain useful pavement surface condition data for pavement evaluation, two direct type road roughness evaluation systems were developed with the combination of modern sensor technology and computer technology. The thesis will focus on the development of the direct type profiler systems, including the improvement of the hardware design, the new direct type road roughness-measuring system using different method, the software development, which makes it more functional. In order to evaluate the accuracy and correction of the direct type profiler system, different roughness devices (including FDOT High-Speed laser profiler, FACE Dipstick and direct type I profiler) were operated in 4 calibration sites. The research focused on several performance measures, such as correlativity, repeatability. IRI and RN results from these devices were analyzed to evaluate the correlativity between these devices. After verified that direct type I profiler has good repeatability and correlation with FDOT High-Speed laser profiler, FACE Dipstick, 10 calibration sites data in Tampa were collected using direct type I profiler and direct type II profiler. The repeatability and correlation analysis between the two profilers were performed. From field experiments and data analysis, it shows: 1.Direct type I profiler showed satisfactory repeatability performances; 2.Direct type I profiler has good RN correlations High-Speed laser profiler; 3.Direct type I profiler has good correlations with Dipstick, High-Speed laser profiler in terms of IRI 4.Direct type II profiler does not has good correlation with direct type I profiler; the performance needs to be improved. Except for these conclusions, it is also found that the High-Speed profiler can be operated at different speeds with little differences in RN values, the sampling rate did show impact on RN value.
602

Effects of Bilingualism, Noise, and Reverberation on Speech Perception by Listeners with Normal Hearing

Febo, Dashielle M 01 March 2003 (has links)
The accurate perception of spoken English is influenced by many variables, including the listener's native language, reverberation, and background noise. Few studies of speech perception by bilingual listeners have carefully controlled for second language proficiency and even fewer have presented speech in everyday listening environments that contain noise and reverberation. In the present study, detailed language background, language proficiency information, and individual language samples were collected and the speech stimuli were presented in a variety of quiet, noisy, and reverberant listening environments. The effects of noise and reverberation on the perception of American English monosyllabic words was examined for two groups of young listeners with normal hearing: 1) monolingual American English speakers and 2) Spanish-English bilinguals who acquired both languages prior to age 6 years, exhibited similar spoken proficiency in both languages, and spoke English without a noticeable accent. An innovative test of virtual speech perception was used to assess word recognition in two listening environments typical of everyday communication: a simulated noisy anechoic environment and a simulated noisy reverberant environment. Word recognition was also measured in quiet and in an unprocessed noisy environment. For each noisy listening environment (unprocessed, anechoic, reverberant), three signal-to-noise ratios were employed. Results indicate that early bilingualism negatively affects perception of words presented in noisy listening environments. Significantly poorer word recognition was observed for the bilingual listeners than for the monolingual listeners in all three noisy environments and at all noise levels. Both groups exhibited similar word recognition in quiet. The results were surprising considering the high level of spoken language proficiency exhibited by all bilingual listeners. It is often assumed that highly proficient Spanish-English speakers are equally proficient at understanding English; however, these data indicate that the speech understanding of this group may be overestimated in natural listening situations.
603

Factores determinantes del desarrollo del E-commerce en el sector retail del Perú, tomando como referencia el país de Chile

Vásquez Rodríguez, Sandy Fabiola Lisset, Zapata Egúsquiza, María Fernanda 12 November 2018 (has links)
Actualmente los consumidores son mucho más exigentes al momento de decidir su compra, valoran no solo el producto sino el servicio que le brindan las empresas; esto quiere decir que evalúan y comparan distintas opciones antes de comprar. Por lo que, la competencia entre las empresas es agresiva y en constante movimiento, no solo en el sector E-commerce, tema del cual abordaremos, sino en todos los mercados del mundo. En este sentido, las empresas deben sumar todos sus esfuerzos en trabajar sus estrategias para brindar el mejor servicio. Respecto al Comercio electrónico, Europa y EEUU son los que lideran la lista de desarrollo del E-commerce en el mundo. Sin embargo, muchos han puesto la mirada en Latinoamérica, como un mercado en plena efervescencia con grandes expectativas de crecimiento. Cabe resaltar que Perú no es ajeno a este crecimiento, ya que contribuye cada año con alrededor del 30% de crecimiento para el 2018. Si bien, En el Perú el comercio electrónico ha tenido un importante crecimiento, aún nos falta camino por recorrer y aprender las mejores prácticas que otros mercados han empleado. Existen distintos factores que influyen en el crecimiento del E-commerce como el nivel de conectividad y la bancarización, aspectos que aun en el Perú son deficientes no solo por la baja participación de las empresas, sino también, por la poca intervención del estado en cuanto a infraestructura tecnológica. Asimismo, dentro del perfil del consumidor, la desconfianza es uno de las razones que limita la evolución del comercio electrónico sin embargo creemos que cada vez es menos frecuente. Desde que se instauró el comercio electrónico en la mente de los consumidores, no ha dejado de crecer; y nos ha enseñado una manera distinta de comprar y vender tanto a empresas como a consumidores. Por ello, en la presente investigación analizaremos los factores determinantes desarrollo del E-commerce en el en el sector Retail del Perú, teniendo una mirada internacional en comparación con las mejores prácticas del mercado chileno. / Currently, there is more to demand at the time of deciding your purchase, assess not only the product but the service provided by the companies; this means that you evaluate and compare options before buying. Therefore, the competition between companies is aggressive and is always in constant movement, not only in the E-commerce sector, subject of which we will address, but in all the markets around the world. In this sense, companies must join all their efforts in their work strategies to provide a better service. Regarding e-commerce, Europe and the US are the leaders in the development of e-commerce worldwide. However, many have looked at Latin America, as an emergent market with high expectations of growth. It should be noted that Peru is not apart to this growth, as it contributes each year with almost 30% of growth for 2018. Although, in Peru, electronic commerce has had an important growth, we have not yet traveled the road and learned the best practices that other markets have used. There are factors that enhance the growth of E-Commerce such as the level of connectivity and banking, aspects that are poorly developed in Peru. These aspects are deficient not only by the low participation of companies, but also by the lack of intervention from the government in respect of technological and logistics infrastructure. As well, talking about the user’s profile, distrust is one of the reasons that limits the evolution of electronic commerce, however, it is becoming less frequent. Since E-Commerce was installed in the minds of users, it has not stopped growing; and it has taught us an innovative way to buy and sell as much as companies and consumers. Therefore, in this research we will analyze the determinants issues of the development of electronic commerce in the retail sector of Peru, taking into account the best practices of the Chilean market. / Tesis
604

Design, Construction, and Characterization of the University of South Florida Wind Tunnel

Garcia, Jason S. 04 June 2018 (has links)
Much of the aerosol research completed at the University of South Florida has revolved around evaluating industrial hygiene equipment and instrumentation in environmental chambers. Data collected during these studies has provided valuable baseline data on equipment and instrument performance under calm air conditions. A newly constructed wind tunnel now allows researchers to evaluate industrial hygiene instruments under moving air conditions. Because the wind tunnel is capable of producing wind velocities that a worker could encounter in the occupational setting, researchers may gain insight into instrument performance under simulated field conditions. Because aerosols can be introduced into the new wind tunnel testing section, researchers can also challenge industrial hygiene equipment and instrumentation with aerosols in sizes ranges that are of interest in public health. The purpose of this dissertation research was to develop a new wind tunnel to be used for aerosol research at the University of South Florida. Three specific aims had to be met for this study to be successful. They included: (1) designing a wind tunnel based on best practice information outlined in scientific literature, (2) constructing an operable wind tunnel to be used for aerosol research, and (3) characterizing wind tunnel performance by examining the wind tunnel velocity profile, turbulence intensity, and aerosol introduction/collection. The actual wind tunnel was constructed to a length of approximately 20 feet, a height of approximately 2 feet at its tallest point, and includes an entrance filter housing, a settling chamber, a contraction, a testing section, a diffuser, an exit filter housing, a fan, and exhaust duct. All components were designed and constructed using guidelines and best practices reported in the scientific literature. Velocity profile measurements were the first way that this wind tunnel was characterized. In order to successfully obtain measurements, the wind tunnel cross section was divided into 16 equal quadrants. Five measurements were taken for each quadrant at each wind velocity. Target wind velocities for this research were 0.5 m/s, 1.0 m/s, and 2.0 m/s. Actual average wind velocities of 0.48 m/s, 1.00 m/s, and 2.04 m/s. All were within established limits reported in the scientific literature. Turbulence intensity measurements were the second way that this wind tunnel was characterized. In order to successfully obtain measurements, the wind tunnel cross section was divided into 16 equal quadrants. Five measurements were taken for each quadrant at each wind velocity. Wind tunnels are typically designed to have the lowest turbulence intensity possible, generally below 10%. The overall average turbulence intensities for this wind tunnel at wind velocities of 0.5 m/s, 1.0 m/s, and 2.0 m/s were 9%, 10%, and 8% respectively. Overall turbulence intensity measurements were at or below 10%. Isokinetic sampling was the final method used to characterize this wind tunnel by collecting and detecting aerosols traveling through the wind tunnel testing section. The wind tunnel was operated at wind velocities of 0.5 m/s, 1.0 m/s, and 2.0 m/s with isokinetic sampling flow rates of 15.4 L/min, 30.9 L/min, and 61.7 L/min respectively. Monodisperse fluorescent polystyrene latex spheres were used as the test aerosol because they are uniform in size and shape and can be detected by fluorometry. The Blaustein Multi-Jet Atomizer (BLAM) was used to generate monodisperse fluorescent polystyrene latex aerosol 0.5 µm and 2.0 µm particles from liquid suspensions. The Vilnius Aerosol Generator (VAG) was used to generate monodisperse fluorescent polystyrene latex aerosol of 6.0 µm and 12.0 µm particles from dry powders. Nitrogen gas was used for delivering test aerosols into the wind tunnel. Five experimental runs were completed for each particle size and wind velocity for a total of 60 experimental runs. Fluorescence was detected in all 60 samples with average mass concentrations ranging from 0.000050 ng/ml to 0.002703 ng/ml. Based on velocity profile measurements, turbulence intensity measurements, and isokinetic sampling, the performance of University of South Florida wind tunnel was found to be excellent, indicating that it was designed and constructed appropriately. The wind tunnel can now successfully be used by researchers interested in evaluating industrial hygiene sampling equipment with aerosols ranging from 0.5 µm to 12.0 µm in moving air with velocities ranging from 0.5 m/s to 2.0 m/s.
605

Características sociodemográficas e de trabalho do profissional da educação física de academia / Sociodemographic and work characteristics of the gym physical education professional

Jesus, Letícia de 18 June 2019 (has links)
Este trabalho teve como objetivo descrever as características sóciodemográficas e de trabalho do profissional da Educação Física da Zona Leste de São Paulo. Como objetivos específicos, identificamos o perfil do profissional e o estilo de vida e saúde, considerando os aspectos de tempo de trabalho, funções exercidas, percepção de satisfação profissional com relação às condições de trabalho, renda e motivação e capacidade para o trabalho do profissional de Educação Física. A metodologia utilizou-se de levantamento bibliográfico, artigos, dissertações e livros, e na utilização de um questionário. Os sujeitos desta pesquisa foram 80 profissionais de Educação Física que atuam nas academias da zona leste de São Paulo. Os itens do questionário foram desmembrados com a finalidade de utilizar os escores pré-definidos de cada instrumento. Foi utilizado o pacote estatístico Statistical Package for the Social Sciences - SPSS 20, estabelecendo uma análise descritiva com cálculos de média, desvio padrão. A maioria dos profissionais era do sexo masculino e tinham média de 33 anos de idade; trabalhavam aproximadamente dois anos na empresa onde foi realizada a pesquisa; dos profissionais, 55 % obtinham de carteira e previdência social. A qualidade de vida e satisfação profissional ficaram na média da classificação boa. Foi identificado uma prevalência baixa de doenças e lesões nestes profissionais. No geral o pentaculo do bem estar teve um resultado positivo para os indicadores de estilo de vida. Podemos afirmar que é uma profissão recente no mercado, e um dos grandes desafios desta área é o processo de envelhecimento e o plano de carreira. Em média esses profissionais tem 2 empregos e dividem a rotina e seu tempo com outras atividades. O gosto pela pratica de atividade física é um fator que colabora para a escolha da profissão em Educação Física. Podemos concluir que os profissionais deste estudo são considerados jovens e fisicamente ativos, além de ter poucos problemas de saúde, uma vez que esses profissionais possuem uma probabilidade maior de cuidar da saúde e ter com o estilo de vida ativo, faz com que os aspectos preventivos sejam mais evidentes / This study aimed to analyze the sociodemographic and work characteristics of the Physical Education professional of the East Zone of São Paulo. As specific objectives, we identify the profile of the professional and aspects of lifestyle and health, considering the aspects of working time, functions exercised, perception of professional satisfaction with regard to working conditions, income and motivation, as well as specify the aptitude for the work of the Physical Education professional. The methodology focused on the bibliographical survey, articles, dissertations and books, and the use of a questionnaire. The subjects of this research were 80 professionals of physical education who work in the academies of the east zone of São Paulo. The items of the questionnaire were dismembered in order to use the pre-defined scores of each instrument. Statistical Package for Social Sciences - SPSS 20 was used, establishing a descriptive analysis with mean, standard deviation calculations. Most of the professionals were male and with an average of 33 years of age; worked for approximately two years in the company where the research was carried out, of the professionals, 55% obtained a portfolio and social security. Quality of life and professional satisfaction were average in the good rating. A low prevalence of diseases and injuries was identified in these professionals. Overall the pentacle of good had a positive outcome for lifestyle indicators. We can state that it is a recent profession in the market, it is one of the great challenges of this area is the aging process and the career plan. On average these professionals have 2 jobs and divide the routine and their time with other activities. The taste for practicing physical activity is a factor that contributes to the choice of the profession in Physical Education. We can conclude that the professionals of this study are considered young and physically active, in addition to having few health problems, since these professionals have a greater probability of taking care of health and having with the active lifestyle, causes that the preventive aspects are more evident
606

Evolution and Equilibration of Artificial Morphologic Perturbations in the Form of Nearshore Berm Nourishments Along the Florida Gulf Coast

Brutsché, Katherine Emily 26 June 2014 (has links)
Inlets and channels are dredged often to maintain navigation safety. It is beneficial to reintroduce the dredged material back into the littoral system, in the form of beach or nearshore nourishments. Nourishment in the nearshore is becoming an increasingly utilized method, particularly for dredged material that contains more fine sediment than the native beach. This research examines the morphologic evolution of two different nearshore nourishments. A nearshore berm was constructed at Fort Myers Beach, Florida using mixed-sized sediment dredged from a nearby channel. The nearshore berm was placed in water depths between 1.2 and 2.4 m with the berm crest just below MLLW in the shape of a bar. The nearshore berm migrated onshore while the system was approaching a dynamic equilibrium. Near the end of the fourth year, the beach profiles had returned to the equilibrium shape characteristic of the study area. Gaps in the berm allowed water circulation and should be considered as a design parameter. The fine sediment fractions in the original placed material was selectively transported and deposited offshore, while the coarser component moved onshore. The dry beach maintained the same sediment properties throughout the study period and was not influenced by the fine sediment in the initial construction of the berm. Another nearshore nourishment was placed along eastern Perdido Key, Florida in 2011-2012 using maintenance dredged material from nearby Pensacola Pass. Different from the Fort Myers Beach berm, the material was placed within the swash-zone, with a maximum elevation of +0.91 m NAVD88 (or 0.62 m above MHHW). The low constructed berm elevation allowed natural overwash processes to occur frequently, which resulted in net onshore sediment transport and growth of the active beach berm. Sediment volume gain west of the project area due to longshore spreading of the nourishment occurred mostly in the trough between the shoreline and the bar, rather than on the dry beach. The swash-zone berm evolved back to the natural equilibrium profile shape maintained in the study area within 8 months. The performance of the swash-zone nourishment was compared to two previous beach nourishments at the same location in 1985 and 1989-1991, with higher berm elevations, at +3 m and +1.2 m NAVD88, respectively. The 1.2-km 1985 nourishment performed the poorest with a shoreline retreat rate of 40 m/year. The 7.3-km 1989-1991 nourishment performed the best with a retreat rate of 11 m/year. This suggests that high berm elevations do not necessarily lead to better nourishment performance. Longshore extent of a nourishment may play an essential role. The distant passage of two tropical storms (Tropical Storm Debby and Hurricane Isaac) generated high waves for the study areas. The two berm nourishments responded differently to the storm. Response was also compared to a beach nourishment in Sand Key. The bar-shaped Fort Myers Beach berm was split into two smaller bars, while a storm berm developed for the swash-zone nourishment at Perdido Key. In both cases, the energetic storm conditions accelerated the evolution of the berm profiles toward equilibrium. As compared to the measured nearshore waves by this study, CMS-Wave accurately propagated the WIS Hindcast waves. SBEACH accurately captured the maximum water elevation, consistent with measured upper limit of morphology change. The model correctly predicted beach and nearshore erosion during the storms. The growth of the storm berm at the Perdido Key swash-zone nourishment was predicted reasonably well by the SBEACH model. However, the magnitudes of the storm-induced erosion and the locations of the offshore bar were not accurately predicted consistently.
607

English K-6 syllabus and support document (1994) : imperilled by politics and paradigm shifts

Pennell, Beverley, University of Western Sydney, Nepean, Faculty of Education January 1997 (has links)
English K-6 syllabus and support document (1994) is NSW's 'Clayton's' Primary English syllabus in that it was released in 1994, was 'on hold' and under review in early 1995 then recommended for revision by 1998. This is an extraordinary example of 'the written curriculum' of subject English, a site of intense ideological and pedagogical contestation. The Report produced by the Eltis Committee of Review, Focus on learning : Report of the Review of Outcomes and Profiles in New South Wales Schooling (1995) recommended immediate revision of 2 aspects of the syllabus in particular : firstly, the removal from English K-6 Syllabus of outcome statements from the National Profiles and secondly, the removal of the model of grammar endorsed in the document, 'Functional Grammar'. The history of the paradigm shift from State outcomes in syllabus documents, to the inclusion of National Profiles outcomes statements, forms the first part of this study. The recommendation of the Eltis Report to remove 'Functional Grammar' from the syllabus was politically motivated and had pedagogical implications for all those teachers, professional English educators and scholars who have been in divisive debate for nearly a decade about the broadest aspect of the frame of 'Functional Grammar', namely genre, or 'text type' as it is termed in English K-6 Syllabus. This study also looks at the history of the genre theory debate about teaching students to write and the paradigm shift that led to the inclusion of genre theory in the 1994 syllabus. This study, then, examines the essentially political nature of the school subject, English, in a regional educational context of the State of NSW. By presenting a brief curriculum history of the English K-6 Syllabus and Support Document (1994) it will be seen that a curriculum document can be a focus for power struggles between State and Commonwealth Governments and a site of contestation within the educational communities who are stakeholders in subject English / Master of Education (Hons)
608

Radiotherapy X-ray dose distribution beneath retracted patient compensators

Piyaratna, Nelson, University of Western Sydney, Nepean, Faculty of Science and Technology January 1995 (has links)
Computer designed missing tissue and dose compensators have been produced and dosimetrically tested under a linear accelerator 6MV X-ray beam. Missing tissues compensators were developed to correct for patient external contour change only. Target dose compensators were developed to achieve a uniform dose throughout the target volume. With compensators present in the beam, data acquisition was repeated in a water phantom and an Anthropomorphic phantom. Clinically acceptable dose uniformity was achieved within these phantoms. For external contour compensation flat isodose curves were obtained giving an even dose in the region of interest. The dose difference found was within plus/minus 3% only. For the phantoms containing inhomogeneities dose uniformity to target volume was achieved within plus/minus 7%. Prediction of radiation dose was made using a GE Target Series 2 Treatment Planning Computer for each of the phantoms. Validation of the computer predicted dose was carried out using diode and TLD measurements. The measured data in the water tank was consistent with the computer data within plus/minus 2% for external contour changes and for inhomogeneities. The TLD measured results in the anthropomorphic phantom agreed with the planning computer results within 6%. Up to 4% of the difference is explainable due to supra-linearity and scatter effects / Master of Science (Hons) (Physics)
609

Contextual information retrieval from the WWW

Limbu, Dilip Kumar January 2008 (has links)
Contextual information retrieval (CIR) is a critical technique for today’s search engines in terms of facilitating queries and returning relevant information. Despite its importance, little progress has been made in its application, due to the difficulty of capturing and representing contextual information about users. This thesis details the development and evaluation of the contextual SERL search, designed to tackle some of the challenges associated with CIR from the World Wide Web. The contextual SERL search utilises a rich contextual model that exploits implicit and explicit data to modify queries to more accurately reflect the user’s interests as well as to continually build the user’s contextual profile and a shared contextual knowledge base. These profiles are used to filter results from a standard search engine to improve the relevance of the pages displayed to the user. The contextual SERL search has been tested in an observational study that has captured both qualitative and quantitative data about the ability of the framework to improve the user’s web search experience. A total of 30 subjects, with different levels of search experience, participated in the observational study experiment. The results demonstrate that when the contextual profile and the shared contextual knowledge base are used, the contextual SERL search improves search effectiveness, efficiency and subjective satisfaction. The effectiveness improves as subjects have actually entered fewer queries to reach the target information in comparison to the contemporary search engine. In the case of a particularly complex search task, the efficiency improves as subjects have browsed fewer hits, visited fewer URLs, made fewer clicks and have taken less time to reach the target information when compared to the contemporary search engine. Finally, subjects have expressed a higher degree of satisfaction on the quality of contextual support when using the shared contextual knowledge base in comparison to using their contextual profile. These results suggest that integration of a user’s contextual factors and information seeking behaviours are very important for successful development of the CIR framework. It is believed that this framework and other similar projects will help provide the basis for the next generation of contextual information retrieval from the Web.
610

The selection of Australian youth soccer players based on physical and physiological characteristics

Hugg, Peter J., n/a January 1996 (has links)
The purpose of this study was to develop a physiological profile of elite Australian Youth soccer players. Over three years, 150 players from the U'17, U'20 and U'23 national squads were tested for six measurements - height, weight, sum of eight skinfolds, vertical jump, maximum oxygen consumption and speed over twenty metres. Comparisons were made between those selected in the final team (classified as Successful) and those who failed to be selected (classified as Unsuccessful) to determine any significant differences between the two groups A physical and physiological profile was obtained for each player - expressed as a single value in both numerical and graphical formats. Players were ranked based on this score to determine significant differences between successful and unsuccessful players. Several significant differences (p<0.05) were found between Successful and Unsuccessful groups for a number of the variables primarily in the performance area rather than in the anthropometry parameters. For all squads, significant differences (P<0.05) were found between those who made the squad and those who did not when ranked based on their physical and physiological score. This study highlights the importance of the application of scientific testing to soccer Furthermore, it provides a system by which players' results can be analysed and ranked, and expressed in a format that provides the coach with immediate feedback as to an individual's specific strengths and weaknesses as a basis for training and team selection.

Page generated in 0.0608 seconds