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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

Coordenação modular: acepções contemporâneas / Modular coordination: contemporary acceptations

Marina Rosa Crespo 23 May 2017 (has links)
A coordenação modular é um sistema para ordenação relativa de dimensões, espaços e componentes construtivos. Sua aplicação tem manifestações remotas por princípios que controlam a composição e fixam escalas convenientes para as partes e o todo, todavia foi a produção seriada industrial que determinou o papel que a disciplina teria no século XX. No Brasil, seu desenvolvimento aconteceu entre as décadas de 1950 e 1970, quando foi determinada a formatação fundamental da disciplina. Identifica-se a partir da década de 1980 um intervalo nas discussões específicas que durou até a virada do século, quando foi recuperado o interesse pela área. É consenso entre os autores que ainda não houve no Brasil sucesso na implantação de modelos abrangentes da coordenação modular, mas faltam análises atualizadas. O objetivo da dissertação - examinar o desenvolvimento da disciplina no Brasil após 1986 - está fundamentado em indícios de que as discussões recentes não se aprofundam em temas atuais e de que há um enfraquecimento de uma visão integrada do problema. As principais conclusões indicam que o desenvolvimento da construção civil vem sendo acompanhado do afastamento da arquitetura de etapas da produção, o que afeta o exercício da coordenação modular e que o programa habitacional e as ações políticas de financiamento foram determinantes para a retomada das pesquisas. Entretanto, há ecos dos modelos estabelecidos pelo setor privado, com ênfase à racionalização e à aplicação de componentes industriais. Diante disso, destaca-se que a coordenação modular, como campo da coordenação dimensional, está ligada às necessidades humanas. / Modular coordination is a system for relative ordering of dimensions, spaces, and building components. Its application presents remote manifestations through principles that control the design and set suitable scales for the parts and the whole. Nevertheless, the industrial mass production defined the role that the subject would play during the 20th century. In Brazil, its development took place between the 1960s and the 1970s; period that several authors consider decisive in what regards the subject\'s fundamental formatting. From the 1980s on, the specific debates about the matter went through a gap that lasted until the turn of the century when the interest in the field resurfaced. It is consensual among authors that Brazil still has not been successful to implement comprehensive modular coordination standards, but there is a lack of up-to-date analysis as well. The objective of the dissertation - to examine the discipline\'s development in Brazil after 1986 - is based on indications that recent discussions are leaving aside current issues and that there is a weakening of an integrated view of the matter. The main conclusions indicate that a dissociation between architecture and construction has accompanied the building industry\'s development, which affects the application of modular coordination. Moreover, the housing program and the research funding were decisive for the resumption of the field; nonetheless, there are echoes from the models established by the private sector, with emphasis on the rationalization and application of industrial components. In this context, it should be noted that modular coordination, as a field of dimensional coordination, is linked to human needs.
12

Why Do We See Three-dimensional Objects?

Marill, Thomas 01 June 1992 (has links)
When we look at certain line-drawings, we see three-dimensional objects. The question is why; why not just see two-dimensional images? We theorize that we see objects rather than images because the objects we see are, in a certain mathematical sense, less complex than the images; and that furthermore the particular objects we see will be the least complex of the available alternatives. Experimental data supporting the theory is reported. The work is based on ideas of Solomonoff, Kolmogorov, and the "minimum description length'' concepts of Rissanen.
13

A Transdiagnostic Model of Suicidal Ideation and Suicide Attempts

Eisner, Lori Rachel 15 January 2010 (has links)
Suicide is one of the most tragic issues in mental health. Suicide has traditionally been studied as an outcome of specific psychiatric disorders. The goal of this study was to consider whether there might be underlying dimensions across psychiatric disorders that are related to suicidality. This study proposed a transdiagnostic model of suicidality. Psychiatric symptoms were hypothesized to load onto three factors: Negative Mood, Impulsivity, and Arousal. Factors were then examined as predictors of suicidal ideation and suicide attempts. Data were drawn from the National Comorbidity Survey-Replication Study (NCS-R). Structured interviews were conducted in two parts using the Composite International Diagnostic Interview (CIDI). All survey respondents (N = 9,282) were administered the core diagnostic assessment. Those who met criteria for a psychiatric disorder, met subthreshold lifetime criteria and sought treatment at some time in their life, or ever in their life made a plan to commit or attempt suicide were administered Part II of the interview and are the sample of interest in this study (N = 5,692). The sample was representative of non-institutionalized civilian adults ages 18 or older whose primary language was English. Factor analyses revealed three modified factors: a Negative Mood/Emotional Arousal factor, a Negative Thinking factor, and a Recurrent Substance Use factor. Negative Mood/Emotional Arousal was a strong predictor of suicidal ideation. Suicidal ideation mediated the relationship between Negative Mood/Emotional Arousal and suicide attempts, controlling for Negative Thinking. Negative Thinking, Recurrent Substance Use, and suicidal ideation predicted suicide attempts. When number of suicide attempts was examined as the dependent variable, the model did not fit the data, suggesting that these factors were not as helpful in predicting highly recurrent suicide attempts. Recurrent Substance Use moderated the relationship between Negative Mood/Emotional Arousal and suicide attempts, demonstrating that, as negative mood increases, people with high levels of recurrent substance use are more likely to make a suicide attempt compared to people with mean or low levels of recurrent substance use. In sum, results of this study support two distinct pathways to making a suicide attempt: a direct relationship between negative thinking and suicide attempts, as well as an interaction between negative mood/emotional arousal and recurrent substance use. Several limitations including issues of sampling, the cross-sectional nature of the data, self-report bias, and the structure of the CIDI instrument, were taken into account in interpreting the results. Clinical implications and future directions for research are discussed.
14

Protein expression in prostate cancer progress

Wang, Yu-Ming 21 August 2002 (has links)
Prostate cancer is one of the most common malignant tumors in solid organs of old men. Prostate-specific antigen (PSA) is a valuable prostate cancer biomarker that is now wildly used for population screening, diagnosis, and monitoring of patients with prostate cancer. Howere it is reported that PSA is not feasible to discriminate the progress of prostate cancer, so many investigators still works on developing new biomarker of prostate carcinoma. Here, we propose the study of differentially expressed prostate proteins in blood of patients. With the aid of two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption-induced time of flight (MALDI-TOF) mass spectrometry, comparison of normal men and prostate cancer patients serum proteins and analysis protein variation of different stages of prostate cancer serum. We find 31 and 17 protein spots overexpression in cancer development and after treatment, respectively. At present, with the aid of SWISS-PORT database and MALDI-TOF mass spectrometry, we had identified fibrinogen gamma chain, fibrinogen alpha/alpha-E chain, major histocompatibility complex (MHC), class I, C and Mayven were overexpressed in prostate cancer development, where Mayven is fist reported by us.
15

Supergravities with positive definite potentials and AdS pp-waves

Kerimo, Johannes 16 August 2006 (has links)
Ten-dimensional superstring theory (or the conjectured nonperturbative Mtheory in eleven dimensions) is the most promising candidate for a consistent quantum theory of gravity capable of unifying all known forces of nature. An important question concerning these fundamental theories is how they compactify to lower dimensions and how to obtain a real four dimensional world? In this dissertation we present new avenues for M/string theory to reduce to lower dimensions as well as to four dimensions. For example, we show that by performing a generalized Kaluza-Klein IR reduction on the low-energy field theory of the heterotic string, the resulting lower dimensional theory compactifies spontaneously on S3 to give rise to (Minkowski)6 spacetime. Furthermore, a generalized reduction of M-theory on K3 × IR compacti- fies spontaneously on S2 to give rise to a (Minkowski)4 spacetime. The generalized Kaluza-Klein reduction gauges the Cremmer-Julia type global symmetry and the homogeneous rescaling symmetry of the supergravity equations of motion by giving the higher dimensional fields an additional dependence on the circle coordinate. We apply the generalized reduction scheme to half-maximal supergravities which are obtained from the heterotic string (or the NS-NS sector of the type-II string) compactified on a (10 − D)-dimensional torus truncated to the pure supergravity multiplet. This gives rise to new gauged supergravities in diverse dimensions with supersymmetric Minkowski × sphere vacua.Since two large extra dimensions have received much attention recently, we make a detailed study of the gauged D = 6, N = (1, 1) supergravity. In particular, we show that this theory allows for a consistent sphere reduction on S2 to give rise to D = 4, N = 2 supergravity coupled to a vector multiplet which can further be truncated to N = 1 supergravity with a chiral multiplet. We also investigate pp-waves in AdS backgrounds, i.e. pp-waves as solutions of gauged supergravities with AdS vacua. These solutions generically preserve 1 4 of the supersymmetry. We demonstrate supernumerary supersymmetries for both purely gravitational pp-waves and pp-waves supported by fields strengths. These new backgrounds provide interesting novel features of the supersymmetry enhancement for the dual conformal field theory in the infinite-momentum frame.
16

Trace diagrams, representations, and low-dimensional topology /

Peterson, Elisha. January 2006 (has links)
Thesis (Ph. D.) -- University of Maryland, College Park, 2006. / Includes bibliographical references (leaves 117-119). Also available online.
17

Topological consistency in skelatal modeling with convolution surfaces for conceptual design

Ma, Guohua, 1970- 28 August 2008 (has links)
This dissertation describes a new topology analysis tool for a skeletal based geometric modeling system for conceptual design. Skeletal modeling is an approach to creating solid models in which the engineer designs with lower dimensional primitives such as points, lines, and triangles. The skeleton is then "skinned over" to create the surfaces of the three-dimensional object. In this research, convolution surfaces are used to provide the flesh to the skeleton. Convolution surfaces are generated by convolving a kernel function with a geometric field function to create an implicit surface. Certain properties of convolution surfaces make them attractive for skeletal modeling, including: (1) providing analytic solutions for various geometry primitives (including points, line segments, and triangles); (2) generating smooth surfaces; and (3) providing well-behaved blending. We assume that engineering designers expect the topology of a skeletal model to be identical to that of the underlying skeleton. However, the topology of convolution surfaces can change arbitrarily, making it difficult to predict the topology of the generated surface from knowledge of the topology of the skeleton. To address this issue, we apply Morse theory to analyze the topology of convolution surfaces by detecting the critical points of the surfaces. We developed an efficient and intelligent algorithm to find the critical points (CPs) by analyzing the skeleton. The critical points provide valuable information about the topology of the convolution surfaces. By tracking the CPs, we know where and what kind of topology changes happen when the threshold value reaches the critical value at the CP. Topology matching is done in two steps: (1) global topology is tested by comparing the Betti numbers (number of component, loops, and voids) of the skeleton and the generated convolution surfaces; (2) with matched Betti numbers, local topology is tested by comparing the location of each loop and void area between the skeleton and surfaces. If the topology does not match, appropriate heuristics for determining parameter values of the convolution surfaces are applied to force the surface topology to match that of the skeleton. A recommend threshold value is then provided to generate the topology matched convolution surfaces.
18

Study of dimensional interrelationships between factors affecting efficient handling, storage and distribution

Hsia, Thomas Ming-Chang 05 1900 (has links)
No description available.
19

Constraints for conductivity in base treated or reduced polyacetylenes, segmented polyacetylenes, and w-diphenyl polyenes

Schomaker, Joseph Anthony 08 1900 (has links)
No description available.
20

Modeling of ethanol extraction in the Karr Reciprocating Plate Column

Eckles, Andrew Jackson, IV 05 1900 (has links)
No description available.

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