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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.
11

Análise numérica de pisos mistos aço-concreto de pequena altura / Numerical analysis of steel-concrete composite slim floor

André Luiz Ramos 11 June 2010 (has links)
Os pisos mistos aço-concreto de pequena altura caracterizam-se pelo embutimento da laje de concreto na altura da viga de aço, sendo a laje apoiada na mesa inferior do perfil. A principal vantagem deste sistema em relação à viga mista convencional é a redução da altura total do composto. Este trabalho tem como objetivo a criação de um modelo numérico construído no software de elementos finitos TNO DIANA®. O modelo proposto nesta pesquisa buscou subsídios para sua validação em resultados experimentais e numéricos realizados em outras pesquisas. Na fase de validação foram alterados diversos fatores a fim de avaliar a influência de cada um deles, calibrando o modelo até que os resultados se aproximassem dos experimentais. Depois que o modelo foi validado, foi analisada a influência de alguns parâmetros no comportamento global da estrutura, entre eles: a resistência do concreto (fck), a consideração de uma tela de armadura passiva colocada na capa de concreto com diferentes taxas de armadura e a variação da espessura da capa de concreto. Os resultados mostraram que o modelo consegue representar de maneira adequada o comportamento da estrutura apesar das simplificações consideradas para a modelagem. / Composite steel-concrete slim floors are characterized by the inlay of the concrete slab on the same plane of the steel beam, with the slab supported by the bottom flange of the profile. The main advantage of this system compared to the conventional mixed beam is the reduction of the overall height of the compound. This study aims to establish a numerical model built in finite element software TNO DIANA®. The model proposed in this research sought subsidies for its validation in experimental and numerical results achieved in others researches. In the validation phase were changed several factors to evaluate the influence of each of them, calibrating the model until the results come closer to the experimental. After the model has been calibrated, were analyzed the influence of some parameters on the overall behavior of the structure, among them: the strength of concrete (fck), the consideration of reinforcement bars placed on the slab with different rates and the variation of the thickness of the concrete slab. The results showed that the model can adequately represent the structural behavior despite the simplifications considered for modeling.
12

Pressões em silos esbeltos com descarga excêntrica / Pressures in slim silos with eccentric discharge

Madrona, Fernanda Scaramal 11 July 2008 (has links)
A maioria dos silos existentes no mundo não apresenta condições ideais de operação devido ao insuficiente conhecimento das pressões exercidas pelo produto armazenado principalmente na situação de descarga. A descarga excêntrica é comum em cooperativas e indústrias pois facilita o acesso na descarga do produto armazenado em trens e caminhões. Em contrapartida, nesta situação surgem pressões assimétricas que são a maior causa de acidentes e colapsos em silos. Até mesmo em silos concêntricos, as pressões assimétricas podem ocorrer. Ainda faltam muitas respostas com relação ao comportamento das pressões na descarga excêntrica, por isso, a maioria das normas internacionais recomenda a adoção de pressões adicionais para levar em conta os efeitos das pressões assimétricas, sendo que, estas recomendações variam muito de uma norma para outra e muitas vezes não são claras em suas afirmações. Este trabalho teve por objetivo principal o estudo teórico e numérico das pressões devidas ao produto armazenado em silos verticais com descarga excêntrica. Os resultados obtidos mostram que para a determinação das ações em silos esbeltos para o armazenamento de produtos de fluxo livre uma boa solução é a utilização dos métodos recomendados pelas normas EUROCODE e DIN, com algumas ressalvas: pressão no fundo do silo segundo a AS, estabelecimento de coeficiente de sobrepressão mínimo de 1,2 e porcentagem mínima de variabilidade das propriedades dos produtos, mesmo quando elas forem obtidas por meio de testes experimentais. / Most of the silos do not meet the ideal requirements for operation ought to many factors. One of the main factors is related to the lack of knowledge about the pressure imposed by the stored material, especially during discharge. In this work, the discharge done through eccentric silos is investigated, which is commonly employed by cooperatives and factories once they facilitate the access of trains and trucks to the discharged product. In those situations there is the occurrence of asymmetric pressure, which is the major cause of collapses and accidents in silos. There are still many pending answers regarding the pressure behavior in eccentric discharge; therefore, most international standards recommend the adoption of additional pressures in order to consider the effects of asymmetric pressures. The recommendations, however, are very diverse and not always clear. The results obtained show that, in order to determine the actions in slim silos for free flow product storage, it is important to use the methods recommended by the EUROCODE and DIN standards, with some exceptions: refer to the AS regarding to the pressure on the bottom of the silo, define the minimum underpressure coefficient as 1.2, and minimum percentage of product property variability, even if they are achieved through experimental tests.
13

Maillages non-structurés en modélisation marine

Legrand, Sébastien 21 April 2006 (has links)
Cette thèse pose les fondations du modèle « the Second-generation Louvain-la-Neuve Ice-ocean Model » (SLIM) qui est basé sur la méthode des éléments finis et les maillages non-structurés. Ce modèle fait partie d'une seconde génération de modèles numériques de circulation marine ou océanique. Notre travail a principalement porté sur les aspects géométriques liés à l'utilisation des maillages non-structurés. Nous avons implémenté un algorithme de triangulation qui génère automatiquement des maillages anisotropes non-structurés sur le plan et la sphère et nous avons défini des stratégies de raffinement de maillage adaptées aux applications marines. Ces stratégies orchestrent la distribution de la taille et de la forme des éléments du maillage afin d'optimiser la précision et le coût en temps de calcul du nouveau modèle. Nous avons aussi abordé l'interpolation contrainte de champs scalaires et vectoriels d'un premier maillage vers un second. L'utilisation conjointe de ces trois outils combinée avec un estimateur d'erreur a posteriori permettra l'adaptation dynamique de maillages au cours de simulations transitoires. Finalement, nous avons bâti les outils géométriques nécessaires à l'écriture d'une formulation discrète des équations de la dynamique des fluides géophysiques sur la sphère. Basée sur un système de coordonnées curvilignes propre à chaque élément du maillage, cette approche originale ne possède aucune des difficultés mathématiques et numériques liées aux singularités des pôles et auxquelles les modèles de la première génération n'ont pu apporter de solution entièrement satisfaisante.
14

Maillages non-structurés en modélisation marine

Legrand, Sébastien 21 April 2006 (has links)
Cette thèse pose les fondations du modèle « the Second-generation Louvain-la-Neuve Ice-ocean Model » (SLIM) qui est basé sur la méthode des éléments finis et les maillages non-structurés. Ce modèle fait partie d'une seconde génération de modèles numériques de circulation marine ou océanique. Notre travail a principalement porté sur les aspects géométriques liés à l'utilisation des maillages non-structurés. Nous avons implémenté un algorithme de triangulation qui génère automatiquement des maillages anisotropes non-structurés sur le plan et la sphère et nous avons défini des stratégies de raffinement de maillage adaptées aux applications marines. Ces stratégies orchestrent la distribution de la taille et de la forme des éléments du maillage afin d'optimiser la précision et le coût en temps de calcul du nouveau modèle. Nous avons aussi abordé l'interpolation contrainte de champs scalaires et vectoriels d'un premier maillage vers un second. L'utilisation conjointe de ces trois outils combinée avec un estimateur d'erreur a posteriori permettra l'adaptation dynamique de maillages au cours de simulations transitoires. Finalement, nous avons bâti les outils géométriques nécessaires à l'écriture d'une formulation discrète des équations de la dynamique des fluides géophysiques sur la sphère. Basée sur un système de coordonnées curvilignes propre à chaque élément du maillage, cette approche originale ne possède aucune des difficultés mathématiques et numériques liées aux singularités des pôles et auxquelles les modèles de la première génération n'ont pu apporter de solution entièrement satisfaisante.
15

CAN SLIM 選股指標在台灣股巿適用性之實證研究

林雨蓉 Unknown Date (has links)
摘 要 本研究參照Deboeck and Ultsch(1998)想法,不同的是利用多變量分析法中的群集分析來將研究樣本做最合適的分群,再檢視各季各群組是否符合各指標門檻值愈多者,未來投資期間所獲得的報酬也較高,甚至超越類指的現象;另外,也針對年複合成長率以及各指標的門檻值做敏感度分析,而投資期間則分別就短期的1個月、中期的3個月以及長期的6個月做為觀察。實證結果如下: 一、利用CAN SLIM選股策略直接篩選投資標的,本研究的研究樣本中幾乎 沒有一家能夠完全符合;若將條件逐漸放寬只利用C, A, L,三個指標或 C、A二個指標來篩選時,較容易選出投資標的,然而,通過篩選的投資標 的在未來投資期間的平均報酬表現卻未必皆能超越類指表現,顯示若利用 CAN SLIM選股策略的指標來直接篩選未必可以為台灣投資人帶來超越 類指的報酬。 二、利用群集分析法將樣本做最合適的分群後,再與類指報酬表現做比較,顯 示傳統產業中的塑膠業在A=3或A=5下的結果差距不大,顯示此產業有較 穩定的特性,然而實證結果也顯示利用符合指標門檻值的多寡來決定當期 投資的標群組未必能確保選出的標的群組未來投資表現會超越類指。而高 科技產業中的資訊電子業在A=3或A=5下結果明顯不同,以A=3較符合預 期,即符合指標門檻值最多的群組在未來的投資期間表現幾乎皆能超越類 指表現,符合此變化快速的產業特性所需。 三、在對各指標進行敏感度分析中,塑膠業仍未有一個強而有力的結果。而在 資訊電子業中 ,以A=3做為分群資料的情況下,維持原始門檻值依然有較 好的表現。 四、在對投資期間進行敏感度分析中,整體而言,若將投資標的持有3到6個 月,其符合指標門檻值最多的群組平均報酬超越類指的比例較高,也就是 利用CAN SLIM選股策略結合群集分析方法,適合中長期的投資持有。
16

Autopolyploid evolution and phylogeography of the slim-leaf onion (Allium amplectens, Alliaceae)

Wheeler, Erica J. 19 February 2010 (has links)
Allium amplectens (Alliaceae) occurs from southern California to southwestern British Columbia. I used nucleotide sequences from the chloroplast trnT-L intergenic spacer to investigate geographic patterns and phylogenetic relationships among ploidy levels in this species. Hexaploids (2n = 42) and diploids (2n = 14) were the rarest cytotypes (1.5% and 11.3% respectively), followed by tetraploids (2n = 28; 39.1%) and triploids (2n = 21; 48.1%). Phylogenetic analysis indicated that polyploids evolved from diploids at least twice, and that transitions among polyploids occurred at least six times. Abundant triploids in this species may facilitate tetraploid formation via the `triploid bridge'. Chromosomal variation and cpDNA haplotype diversity were highest in California. Nested Clade Phylogeographic Analysis indicated range expansion northward from California in two of three cpDNA clades, with subsequent range contraction and fragmentation. In British Columbia, where A. amplectens is considered at risk, two distinct morphological variants (3x and 4x respectively) were found.
17

"I'm a hustler" (or used to be) creating alternative Black masculinities in post-Civil Rights Era African American hustler narratives /

Garnes, Lamar J. January 2005 (has links)
Thesis (M. A.)--Florida State University, 2005. / Advisor: Christopher Shinn, Florida State University, College of Arts and Sciences, Dept. of English. Title and description from dissertation home page (viewed Feb. 6, 2006). Document formatted into pages; contains vii, 81 pages. Includes bibliographical references.
18

Pressões em silos esbeltos com descarga excêntrica / Pressures in slim silos with eccentric discharge

Fernanda Scaramal Madrona 11 July 2008 (has links)
A maioria dos silos existentes no mundo não apresenta condições ideais de operação devido ao insuficiente conhecimento das pressões exercidas pelo produto armazenado principalmente na situação de descarga. A descarga excêntrica é comum em cooperativas e indústrias pois facilita o acesso na descarga do produto armazenado em trens e caminhões. Em contrapartida, nesta situação surgem pressões assimétricas que são a maior causa de acidentes e colapsos em silos. Até mesmo em silos concêntricos, as pressões assimétricas podem ocorrer. Ainda faltam muitas respostas com relação ao comportamento das pressões na descarga excêntrica, por isso, a maioria das normas internacionais recomenda a adoção de pressões adicionais para levar em conta os efeitos das pressões assimétricas, sendo que, estas recomendações variam muito de uma norma para outra e muitas vezes não são claras em suas afirmações. Este trabalho teve por objetivo principal o estudo teórico e numérico das pressões devidas ao produto armazenado em silos verticais com descarga excêntrica. Os resultados obtidos mostram que para a determinação das ações em silos esbeltos para o armazenamento de produtos de fluxo livre uma boa solução é a utilização dos métodos recomendados pelas normas EUROCODE e DIN, com algumas ressalvas: pressão no fundo do silo segundo a AS, estabelecimento de coeficiente de sobrepressão mínimo de 1,2 e porcentagem mínima de variabilidade das propriedades dos produtos, mesmo quando elas forem obtidas por meio de testes experimentais. / Most of the silos do not meet the ideal requirements for operation ought to many factors. One of the main factors is related to the lack of knowledge about the pressure imposed by the stored material, especially during discharge. In this work, the discharge done through eccentric silos is investigated, which is commonly employed by cooperatives and factories once they facilitate the access of trains and trucks to the discharged product. In those situations there is the occurrence of asymmetric pressure, which is the major cause of collapses and accidents in silos. There are still many pending answers regarding the pressure behavior in eccentric discharge; therefore, most international standards recommend the adoption of additional pressures in order to consider the effects of asymmetric pressures. The recommendations, however, are very diverse and not always clear. The results obtained show that, in order to determine the actions in slim silos for free flow product storage, it is important to use the methods recommended by the EUROCODE and DIN standards, with some exceptions: refer to the AS regarding to the pressure on the bottom of the silo, define the minimum underpressure coefficient as 1.2, and minimum percentage of product property variability, even if they are achieved through experimental tests.
19

Exploring the Accuracy of Existing Effort Estimation Methods for Distributed Software Projects-Two Case Studies / Exploring adekvata befintliga Ansträngningszoner beräkningsmetoder för distribuerad programvara Projekt-två fallstudier

Khan, Abid Ali, Muhammad, Zaka Ullah January 2009 (has links)
The term “Globalization” brought many challenges with itself in the field of software development. The challenge of accurate effort estimation in GSD is one among them. When talking about effort estimation, the discussion starts for effort estimation methods. There are a number of effort estimation methods available. Existing effort estimation methods used for co-located projects are might not enough capable to estimate effort for distributed projects. This is why; ratio of failure of GSD projects is high. It is important to calibrate existing methods or invent new with respect to GSD environment. This thesis is an attempt to explore the accuracy of effort estimation methods for distributed projects. For this purpose, the authors selected three estimation approaches: COCOMO II, SLIM and ISBSG. COCOMO II and SLIM are two well known effort estimation methods, whereas, ISBSG is used to check the trend of a project depending upon its (ISBSG’s) repository. The selection of the methods and approaches was based on their popularity and advantages over other methods/approaches. Two finished projects from two different organizations were selected and analyzed as case studies. The results indicated that effort estimation with COCOMO II deviated 15.97 % for project A and 9.71% for project B. Whereas, SLIM showed the deviation of 4.17% for project A and 10.86 % for project B. Thus, the authors concluded that both methods underestimated the effort in the studied cases. Furthermore, factors that might cause deviation are discussed and several solutions are recommended. Particularly, the authors state that existing effort estimation methods can be used for GSD projects but they need calibration by considering GSD factors to achieve accurate results. This calibration will help in process improvement of effort estimation.
20

Webová a mobilní aplikace pro Seznamovák / Web and Mobile App for Seznamovák

Mikulík, Jan January 2019 (has links)
Main task of this thesis is to design and implement mobile and web application for acquainted stay called Seznamovák. Web application serves for data administration, which are afterwards downloaded by mobile application. Mobile application is used to display downloaded data, such as notifications, program of Seznamovák and area map. The reader will be introduced to requirement analysis with already existing applications. It will also describe analysis of used technologies. Then final solution design and it's implemention with testing.

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