164 resultados para shadowing


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In this paper, we consider multiple-input multiple- output (MIMO) maximal ratio combining (MRC) systems and assess the system performance in terms of average symbol error probability (SEP), outage probability and ergodic capacity in double-correlated Rayleigh-and-Lognormal fading channels. In order to derive the receive and transmit correlation functions needed for the performance analysis, a three-dimensional (3D) MIMO mobile-to-mobile (M-to-M) channel model, which takes into account the effects of fast fading and shadowing is used. Numerical results are provided to show the effects of system parameters, such as maximum elevation angle of scatterers, orientation angle of antenna array in the x-y plane, angle between x-y plane and the antenna array orientation, and degree of scattering in the x-y plane, on the system performance.

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Vegetation and building morphology characteristics are investigated at 19 sites on a north-south LiDAR transect across the megacity of London. Local maxima of mean building height and building plan area density at the city centre are evident. Surprisingly, the mean vegetation height (zv3) is also found to be highest in the city centre. From the LiDAR data various morphological parameters are derived as well as shadow patterns. Continuous images of the effects of buildings and of buildings plus vegetationon sky view factor (Ψ) are derived. A general reduction of Ψ is found, indicating the importance of including vegetation when deriving Ψ in urban areas. The contribution of vegetation to the shadowing at ground level is higher during summer than in autumn. Using these 3D data the influence on urban climate and mean radiant temperature (T mrt ) is calculated with SOLWEIG. The results from these simulations highlight that vegetation can be most effective at reducing heat stress within dense urban environments in summer. The daytime average T mrt is found to be lowest in the densest urban environments due to shadowing; foremost from buildings but also from trees. It is clearly shown that this method could be used to quantify the influence of vegetation on T mrt within the urban environment. The results presented in this paper highlight a number of possible climate sensitive planning practices for urban areas at the local scale (i.e. 102- 5 × 103 m).

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The effect of variations in land cover on mean radiant surface temperature (Tmrt) is explored through a simple scheme developed within the radiation model SOLWEIG. Outgoing longwave radiation is parameterised using surface temperature observations on a grass and an asphalt surface, whereas outgoing shortwave radiation is modelled through variations in albedo for the different surfaces. The influence of surface materials on Tmrt is small compared to the effects of shadowing. Nevertheless, altering ground surface materials could contribute to a reduction on Tmrt to reduce the radiant load during heat-wave episodes in locations where shadowing is not an option. Evaluation of the new scheme suggests that despite its simplicity it can simulate the outgoing fluxes well, especially during sunny conditions. However, it underestimates at night and in shadowed locations. One grass surface used to develop the parameterisation, with very different characteristics compared to an evaluation grass site, caused Tmrt to be underestimated. The implications of using high resolution (e.g. 15 minutes) temporal forcing data under partly cloudy conditions are demonstrated even for fairly proximal sites.

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A systematic determination of the gluon distribution is of fundamental interest in understanding the parton structure Of nuclei and the QCD dynamics. Currently, the behavior of this distribution at small x (high energy) is completely undefined. In this Letter we analyze the possibility of constraining the nuclear effects present in Xg(A) using the inclusive observables which would be measured in the future electron-nucleus collider at RHIC. We demonstrate that the Study of nuclear longitudinal and charm structure functions allows to estimate the magnitude of shadowing and antishadowing effects in the nuclear gluon distribution. (C) 2008 Elsevier B.V. All rights reserved.

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In this work we evaluate the performance of routing protocols for mobile ad hoc networks using different physical layer models. The results obtained show that the performance results obtained using idealized models such as the free space propagation model vary significantly when propagation effects such as path loss and shadowing are considered. This difference in performance indicates that optimization is required in the protocol development space that takes into account channel state information (CSI). Such an optimization requires a cross layer approach to be adopted and a framework for protocol performance evaluation to be established. We believe that this work would serve as a first step in this direction. We provide comparative performance results through network simulations.

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The definition of semi-hyperbolic dynamical systems generated by Lipschitz continuous and not necessarily invertible mappings in Banach spaces is presented in this thesis. Like hyperbolic mappings, they involve a splitting into stable and unstable spaces, but a slight leakage from the strict invariance of the spaces is possible and the unstable subspaces are assumed to be finite dimensional. Bi-shadowing is a combination of the concepts of shadowing and inverse shadowing and is usually used to compare pseudo-trajectories calculated by a computer with the true trajectories. In this thesis, the concept of bi-shadowing in a Banach space is defined and proved for semi-hyperbolic dynamical systems generated by Lipschitz mappings. As an application to the concept of bishadowing, linear delay differential equations are shown to be bi-shadowing with respect to pseudo-trajectories generated by nonlinear small perturbations of the linear delay equation. This shows robustness of solutions of the linear delay equation with respect to small nonlinear perturbations. Complicated dynamical behaviour is often a consequence of the expansivity of a dynamical system. Semi-hyperbolic dynamical systems generated by Lipschitz mappings on a Banach space are shown to be exponentially expansive, and explicit rates of expansion are determined. The result is applied to a nonsmooth noninvertible system generated by delay differential equation. It is shown that semi-hyperbolic mappings are locally φ-contracting, where -0 is the Hausdorff measure of noncompactness, and that a linear operator is semi-hyperbolic if and only if it is φ-contracting and has no spectral values on the unit circle. The definition of φ-bi-shadowing is given and it is shown that semi-hyperbolic mappings in Banach spaces are φ-bi-shadowing with respect to locally condensing continuous comparison mappings. The result is applied to linear delay differential equations of neutral type with nonsmooth perturbations. Finally, it is shown that a small delay perturbation of an ordinary differential equation with a homoclinic trajectory is ‘chaotic’.

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This project explores the ways that creative practices—improvised movement, choreographed dance, and digital video—produce new knowledge about the sociability of public space. In other words, it uses various theoretical concepts and practical strategies to document and analyse the ways people inhabit and sometimes subvert public spaces — such as plazas, malls and piazzas — as part of their everyday experience. Drawing on concepts developed within the fields of performance theory, spatial history, cultural geography and social theory, the project will build a methodological toolbox for understanding the relationships between the diverse groups that use public spaces in Melbourne, Australia. This ‘toolbox’ will subsequently be used to understand analogous public spaces in other parts of the world to generate comparative data about spatial sociability. The research will enable an innovative way of mapping social, civic and political relations in space through a series of creative interventions, and will reveal the politics of everyday movement while exposing tensions between the spaces of public culture — those framed and legitimated by state institutions — and what Michael Warner calls ‘Counter-Publics.’ That is, those oppositional groups who actively seek to use public space in subversive or unauthorised ways.

This project documents a series of performative interventions designed to harness the untapped potential of various forms of street performance genres to function as tools that can produce new ways of understanding the politics of movement in public space. These ‘interventions’ will be generated through a series of practical performance and movement workshops that will draw on street theatre techniques, contact improvisation, Laban movement analysis and contemporary dance choreography. The project will focus on a series of dyadic relationships: self and other, inside and outside, centre and periphery that are relevant to human interaction in public space.
Street performers — musicians, acrobats, jugglers, magicians, mimes and so on — seek public spaces with high volumes of pedestrian traffic in order to maximise their ability to draw an audience and make a living. These performers who create temporary performance zones alter the flow and intensity of movement around them, thereby transforming the plazas, piazzas, town squares and subways favoured by buskers. Some of these performers interact with their audience more than others, and are potentially capable of telling us something about the politics of space. The practice of ‘shadowing’ the movements of passers-by is an increasingly popular form of public entertainment around the world.

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Neste trabalho estudamos um sistema de equações diferenciais parabólicas que modelam um processo de difusão-reação em duas dimensões da mistura molecular e reação química irreverssível de um só passo entre duas espécies químicas A e B para formar um produto P. Apresentamos resultados analíticos e computacionais relacionados à existência e unicidade da solução, assim como estimativas do erro local e global utilizando elementos finitos. Para os resultados analíticos usamos a teoria de semigrupos e o principio do m´aximo, e a simulação numérica é feita usando diferenças finitas centrais e o esquema simplificado de Ruge-Kutta. As estimativas do erro local para o problema semi-discretizado são estabelecidas usando normas de Sobolev, e para estimar o erro global usamos shadowing finito a posteriori. Os resultados computacionais obtidos mostram que o comportamento da solução está dentro do esperado e concorda com resultados da referências. Assim mesmo as estimativas do erro local e global são obtidas para pequenos intervalos de tempo e assumindo suficiente regularidade sobre a velocidade do fluído no qual realiza-se o processo. Destacamos que a estimativa do erro global usando shadowing finito é obtida sob hipóteses a posteriori sobre o operador do problema e o forte controle da velocidade numa vizinhança suficientemente pequena.

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O objetivo desta dissertação é compreender a forma como se estrutura o trabalho dos vendedores e gerente de uma loja de experiência para a transmissão da experiência da marca. O embasamento teórico que deu sustentação à pesquisa aborda discussões sobre o aspecto experiencial do consumo (Holbrook & Hirchsman, 1982b Pine & Gilmore, 2000), experiência da marca (Brakus et al., 2009) e trabalho emocional (Hochschild, 1982; Korczysnki, 2005). Este estudo buscou, através dos métodos shadowing e etnografia de curto prazo, analisar o trabalho dos vendedores e gerente de uma loja de experiência de marca brasileira Chilli Beans, para identificar como estes trabalhadores transmitem a experiência da marca aos consumidores. Os resultados foram coletados durante 45 dias de pesquisa em campo, realizada na loja de experiência da marca Chilli Beans localizada na Rua Oscar Freire, em São Paulo. Ao longo da pesquisa de campo foi possível obter informações sobre a rotina dos trabalhadores, treinamentos, reuniões de avaliação de desempenho e eventos, que proporcionaram a compreensão sobre o trabalho realizado na loja de experiência. Além disso, foram realizadas entrevistas com cinco funcionários da loja, do sexo feminino e masculino, entre 18 e 26 anos, residentes na cidade de São Paulo. Os resultados demonstraram que os trabalhadores utilizam o trabalho emocional para a transmissão da experiência da marca. O trabalho destes vendedores se caracteriza pela busca do atendimento pleno do consumidor, mediante interação emocional, soberania e encantamentos que direcionam o consumidor à aquisição de seus produtos. Para isso, a marca lança mão de treinamentos que objetivam desenvolver as habilidades e técnicas dos vendedores para envolver emocionalmente o consumidor, a fim de direcioná-lo à compra do produto.

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Standardization and sustainability: these two apparently antagonistic words find the challenge of uniting in a flexible architectonic proposal. This was the idea that motivated the proposal of this assignment, whose appearing is bound up with the necessity of thinking about standardized spaces that attend on functional criterias and environmental sustainability, in reply to an existing real demand. The assignment consists of an architectonic proposal for a flexible standard of a Basic Unit of Health for the bioclimatic zone 7 of RN (UBS RN-7), with emphasis in the environmental sustainability. The project contemplates innumerable involved variables, such as: obedience to the current law of the Health Ministry for the UBSs; formal/aesthetic aspects; criterias of expansiveness of the UBS I for the UBS II; relative aspects to the constructive rationality and, mainly, sustainability aspects. With the intention to unite the variables and, also, glimpsing a proposal that could reach a good functional performance, aesthetic, of environment comfort and energetic efficiency, it was also necessary to consider concepts about the flexibility of the envelopment. The elaboration of the architecture first draft was based on bibliographical research, conceptual studies and references, elaboration of the architectonic program and the draft development for the UBS port I and the UBS port II. To the end, an implantation data sheet for the project is proposed for the UBS standard project, where strategies of thermal isolation, shadowing and thermal inertia are adopted and combined to three possible types of lot, resulting in 24 possibilities of implantation

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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We study the surface morphology evolution of ZnO thin films grown on glass substrates as a function of thickness by RF magnetron sputtering technique. The surface topography of the samples is measured by atomic force microscopy (AFM). All AFM images of the films are analyzed using scaling concepts. The results show that the surface morphology is initially formed by a small grains structure. The grains increase in size and height with growth time resulting in the formation of a mounds-like structure. The growth exponent, beta, and the exponent defining the evolution of the characteristic wavelength of the surface, p, amounted to beta = 0.76 +/- 0.08 and p = 0.3 +/- 0.05. From these exponents, the surface morphology is determined by the nonlocal shadowing effects, that is the dominant mechanism, due to the incident deposition particles during film growth.

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OBJETIVO: analisar qual das características propostas pelo BIRADS-US tem maior impacto na diferenciação das lesões benignas das malignas. MÉTODOS: estudamos as características ultra-sonográficas do BIRADS em 384 nódulos submetidos à biópsia percutânea no período de fevereiro de 2003 a dezembro de 2006. Utilizou-se, para o exame, o aparelho Logic 5, com transdutor linear multifreqüencial de 7,5-12 MHz. A análise ultra-sonográfica do nódulo foi baseada no BIRADS-US levando em conta: forma, orientação, margem, limites da lesão, ecogenicidade, características acústicas posteriores, o tecido circunjacente e a presença de calcificações. Estes dados foram submetidos à análise estatística com modelo de regressão logística. Para o estudo de associação entre estas variáveis utilizamos o teste do c² e também calculamos a sensibilidade e a especificidade das variáveis tecido ao redor, calcificações, efeito posterior, limite da lesão e orientação. RESULTADOS: as lesões benignas representaram 42,4% e as malignas, 57,6%. A análise por regressão logística encontrou odds ratio (OR) aumentado para câncer de 7,7 vezes quando o tecido ao redor esteve alterado, de 6,2 vezes quando houve presença das microcalcificações no interior das lesões, de 1,9 quando o efeito acústico foi sombra, de 25,0 vezes quando houve o halo ecogênico e de 7,1 vezes quando a orientação foi não paralela. CONCLUSÕES: dentre as características estudadas, o limite da lesão, representado pela presença ou não do halo ecogênico, é o mais importante diferenciador das massas benignas das malignas.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O objetivo desse trabalho foi verificar a viabilidade do uso de um Sistema de Informações Geográficas (SIG) e a imagem de satélite para a análise do uso atual da terra e localização de áreas onde possam estar ocorrendo conflitos entre capacidade e uso do solo, na microbacia hidrográfica do Arroio do Meio. Foram utilizadas técnicas de geoprocessamento, como álgebra entre mapas, consulta ao banco de dados e reclassificação de imagens. Uma microbacia foi escolhida como objeto deste estudo, por ser considerada por muitos autores como sendo uma das melhores unidades para o planejamento e desenvolvimento sócioeconômico dos habitantes do meio rural. Na microbacia estudada, foram encontrados 555ha cobertos com florestas, compreendendo 24% da área total. As lavouras com área de 1.314ha ocupam a maior parte da microbacia (56%). Os campos de pastagens cobrem 184ha, ou seja, 8% da área total. As áreas alagadas representam 11% da área da microbacia, tendo respectivamente 265ha. Foram detectados ainda, 31ha sombreados (1%) onde não se determinou com exatidão o uso da terra. Nas áreas com declividade superior a 47%, foram detectados 32ha sem cobertura de florestas, perfazendo 1,4% da área da microbacia. em declives superiores a 30%, existem 71ha (3%) sendo usados para a agricultura. A área ocupada com Chernossolos e Neossolos Litólicos, unidade de mapeamento Ciríaco-Charrua em declividade maior que 30% sem cobertura florestal é de 14ha (0,6%). de acordo com a declividade e o solo, as áreas de conflito alcançam 5% da área total, o que demonstra que, na maior parte da microbacia, a terra está sendo usada de acordo com sua capacidade.