• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 10
  • 9
  • 3
  • 1
  • 1
  • Tagged with
  • 28
  • 28
  • 10
  • 7
  • 6
  • 6
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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.
1

The effect of obstructions on the design of artificial lighting installations

McEwan, I. January 1986 (has links)
No description available.
2

Virtual imaging system

Wang, Lulu January 2009 (has links)
The main purpose of this research project was to implement a combination of computer graphics and processing to generate displays that will aid in the visualization of the colour rendering properties of a range of light sources, including the new generation of high-output LEDs (light emitting diodes) that are becoming widely adopted in general lighting service. The CIE (International Commission on Illumination) has developed a colour appearance model CIECAM02 for use in colour imaging and colour management, and this model is utilized in this work. This thesis describes the design and construction of a computer-based model that can be used as a research tool for the simulation and demonstration of the colour rendering properties of various artificial light sources. It is a comprehensive study of the colour models and measurement procedures currently in use in the lighting industry, as recommended by the CIE. This research project focused on the display of a set of surface colour patches as if they were illuminated by a specific light source, and the simultaneous display of two such sets to demonstrate the surface colour differences arising from the use of the two different light sources. A VIS (virtual imaging system) has been developed to display the colour properties of a series of test colour samples under different light sources. This thesis describes the computer models developed for the representation and display of surface colours in general, and colour rendering in particular. The designed system computes and displays the colour of each sample from a knowledge of the light-source spectrum and the spectral reflectance of each surface. It can simultaneously display the colours resulting from illumination by two different sources. In addition, the system computes the colour appearance differences for two sets of colours using the CIECAM02 colour appearance model. Subjective and objective tests were taken to validate the computed results. The VIS has been designed and implemented. It also has been tested by 21 observers and we believe that it will be a powerful research tool for the lighting industry, especially in relation to colour rendering.
3

Predicting time-varying illuminance in complex spaces with lighting control systems

Cropper, Paul January 2001 (has links)
In response to environmental concerns, demands for improved energy efficiency and a desire to create a more pleasant working environment; building designers are looking for ways to make better use of natural light. However, whilst natural light is both free and non-polluting, it can also produce high levels of visual contrast and glare, and unwanted heat. Most current design techniques estimate the natural internal illumination that results from an overcast sky; they do not include the contribution by direct sunlight entering the space, which is often the source of unwanted characteristics. Whilst a sophisticated computer ray-tracing program (RADIANCE) exists that can predict the full range of natural illumination, each prediction can take several minutes (or longer) to calculate. The time required to examine how a natural lighting design behaves over a typical year can therefore be prohibitive. Techniques for estimating the illumination provided by artificial lights also predict illumination under static conditions. Current techniques are therefore unsuitable for examining the dynamic behaviour of a lighting design, which links the automatic control of artificial lights to the changing levels of natural light. The aim of this research was to develop a computer based lighting design tool that overcomes these limitations. Based on the calculation of lighting coefficients, the numeric relationship between the luminance of light sources and the illuminance they produce, the Dynamic Lighting System (DLS) is able to calculate time-varying illuminance from a combination of natural light and artificial lights controlled by a lighting control system. The DLS has been written using the platform independent programming language Java. It is therefore able to run unaltered on most computer platforms, although in practice is limited to platforms on which the ray-tracing program RADIANCE will run, as RADIANCE is used to calculate coefficients. The DLS has been tested by comparing predicted levels of illuminance with levels measured in a test room under real sky conditions. These comparisons showed a high degree of correlation, but with a few large discrepancies. Possible causes of these discrepancies are offered and suggestions made about how they might be eliminated.
4

Virtual imaging system

Wang, Lulu January 2009 (has links)
The main purpose of this research project was to implement a combination of computer graphics and processing to generate displays that will aid in the visualization of the colour rendering properties of a range of light sources, including the new generation of high-output LEDs (light emitting diodes) that are becoming widely adopted in general lighting service. The CIE (International Commission on Illumination) has developed a colour appearance model CIECAM02 for use in colour imaging and colour management, and this model is utilized in this work. This thesis describes the design and construction of a computer-based model that can be used as a research tool for the simulation and demonstration of the colour rendering properties of various artificial light sources. It is a comprehensive study of the colour models and measurement procedures currently in use in the lighting industry, as recommended by the CIE. This research project focused on the display of a set of surface colour patches as if they were illuminated by a specific light source, and the simultaneous display of two such sets to demonstrate the surface colour differences arising from the use of the two different light sources. A VIS (virtual imaging system) has been developed to display the colour properties of a series of test colour samples under different light sources. This thesis describes the computer models developed for the representation and display of surface colours in general, and colour rendering in particular. The designed system computes and displays the colour of each sample from a knowledge of the light-source spectrum and the spectral reflectance of each surface. It can simultaneously display the colours resulting from illumination by two different sources. In addition, the system computes the colour appearance differences for two sets of colours using the CIECAM02 colour appearance model. Subjective and objective tests were taken to validate the computed results. The VIS has been designed and implemented. It also has been tested by 21 observers and we believe that it will be a powerful research tool for the lighting industry, especially in relation to colour rendering.
5

A influência dos espectros da luz em usuários residenciais / The influence of light spectra on residential users

Eder Ferreira dos Santos 26 May 2017 (has links)
Este estudo tem como objetivo introduzir ao leitor a influência da luz sobre os usuários residenciais, mostrando que o avanço das tecnologias ao longo da história e o acesso à iluminação artificial elétrica proporcionaram maior conforto às atividades relacionadas a sua moradia. Novas tecnologias, mais econômicas do ponto de vista energético, possibilitaram acesso a maiores quantidades de luz pelos usuários com diferentes tons de luz branca, permitindo uma maior escolha, porém podendo influenciar na produção do hormônio melatonina, o qual regula o relógio biológico, provocando distúrbios diversos. O trabalho de campo foi realizado em residências, dividido em duas linhas de raciocínio, sendo o primeiro à leitura em uma amostra de residências aleatórias e o segundo com base em uma residência utilizada como modelo. Entretanto, nesse último caso foram alteradas as tecnologias empregadas. Em ambos os casos foram feitas medições na sala de estar em frente à televisão. Esses estudos foram fundamentados no método de Circadian Stimulus (Rea M.S., 2005, 2011), baseado em diversos estudos laboratoriais, que demostraram a influência da luz sobre a produção de melatonina, onde foi empregado nos dois procedimentos adotados. Conclui-se que, apesar da estimativa dos níveis de supressão encontrados serem baixas, as tecnologias com temperaturas de cor mais elevadas, ou seja, luzes mais brancas, tem índices de inibição maiores e devem ser evitadas, assim como as quantidades de luz praticadas para os ambientes residenciais devem ser cuidadosamente dimensionadas. Esse trabalho não tem caráter conclusivo e sim introduz uma metodologia que ainda está em fase final de estudos, porém pode contribuir para apontar diretrizes até então pouco abordadas na prática profissional e terem o intuito de orientar os usuários finais. / This study aims to introduce the reader to the influence of light on residential users, showing that the advancement of technologies throughout history and access to electric artificial lighting have provided greater comfort to the activities related to their homes. New technologies, more economically energetic, allowed access to greater amounts of light by users with different white light tones, allowing a wide choice, but may influence the production of the hormone melatonin, which regulates the biological clock, causing many disturbances. Fieldwork was carried out in residences, divided into two lines of reasoning, the first to be read in a sample of random households and the second based on a residence used as a model. However, in the latter case, the technologies employed were altered. In both cases measurements were taken in the living room in front of the television. These studies were based on the Circadian Stimulus method (Rea M.S., 2005, 2011), based on several laboratory studies, which demonstrated the influence of light on the production of melatonin, where it was used in the two adopted procedures. It is concluded that, although estimates of suppression levels found are low, technologies with higher color temperatures, meaning whiter lights, have higher inhibition rates and should be avoided, as well as the amounts of light practiced for residential environments must be carefully dimensioned. This work does not have a conclusive character but rather introduces a methodology that is still in the final phase of studies, but it can contribute to point out guidelines that have not been approached in the professional practice and are intended to guide end users
6

Rethinking urban lighting : geographies of artificial lighting in everyday life

Ebbensgaard, Casper Laing January 2017 (has links)
In this thesis I study the role of artificial lighting in the everyday urban life of older residents living in the London Borough of Newham. Newham's light infrastructure is currently undergoing change as the borough's entire 19,000 street lamps are being re-placed with Light Emitting Diodes and as a range of regeneration projects provide public spaces designed with new lighting. By increasing visibility and encouraging everyday activity into the evening, the Council claims that the changes in public light-ing will provide 'eyes on the streets' and encourage 'eyes from the windows' of build-ings, contributing to increasing 'natural surveillance'. The Council's avowal of every-day practices in streets and in homes, has made me question how lighting affects the way older residents move through streets and carry out domestic practices as dark-ness falls. The study explores how light planning, lighting design and everyday, rou-tine practices in the public realm and inside homes co-produce the urban, lit environ-ment. Two major contributions of the thesis lie in the (post)phenomenological ap-proach I develop to study everyday experiences of urban lighting, and the methodo-logical framework I employ to research such practices, which combines mobile and visual methods. I have conducted 11 in-depth interviews with nine different planners and designers, 12 walk-along interviews with 22 residents between 58 and 79 years old, and a collaborative photography project with 14 residents between 68 and 96 years old. As I show how older residents experiences different lighting technologies, layers of light, and different lit spaces in their neighbourhoods, I discuss how urban lighting makes them see, feel and carry out routine practices in particular ways. Based on my findings, I argue that urban lighting shapes what, and how, people see, but how people see depends on how they negotiate changes in lighting. In a range of examples where residents mould the urban, lit environment or respond to lighting in different ways, I show how they play and active part in co-producing ways of seeing. I argue it is crucial that light planners and lighting designers recognise such co-constitutive role of everyday practices in order to ensure better lighting for our future cities.
7

A influência dos espectros da luz em usuários residenciais / The influence of light spectra on residential users

Santos, Eder Ferreira dos 26 May 2017 (has links)
Este estudo tem como objetivo introduzir ao leitor a influência da luz sobre os usuários residenciais, mostrando que o avanço das tecnologias ao longo da história e o acesso à iluminação artificial elétrica proporcionaram maior conforto às atividades relacionadas a sua moradia. Novas tecnologias, mais econômicas do ponto de vista energético, possibilitaram acesso a maiores quantidades de luz pelos usuários com diferentes tons de luz branca, permitindo uma maior escolha, porém podendo influenciar na produção do hormônio melatonina, o qual regula o relógio biológico, provocando distúrbios diversos. O trabalho de campo foi realizado em residências, dividido em duas linhas de raciocínio, sendo o primeiro à leitura em uma amostra de residências aleatórias e o segundo com base em uma residência utilizada como modelo. Entretanto, nesse último caso foram alteradas as tecnologias empregadas. Em ambos os casos foram feitas medições na sala de estar em frente à televisão. Esses estudos foram fundamentados no método de Circadian Stimulus (Rea M.S., 2005, 2011), baseado em diversos estudos laboratoriais, que demostraram a influência da luz sobre a produção de melatonina, onde foi empregado nos dois procedimentos adotados. Conclui-se que, apesar da estimativa dos níveis de supressão encontrados serem baixas, as tecnologias com temperaturas de cor mais elevadas, ou seja, luzes mais brancas, tem índices de inibição maiores e devem ser evitadas, assim como as quantidades de luz praticadas para os ambientes residenciais devem ser cuidadosamente dimensionadas. Esse trabalho não tem caráter conclusivo e sim introduz uma metodologia que ainda está em fase final de estudos, porém pode contribuir para apontar diretrizes até então pouco abordadas na prática profissional e terem o intuito de orientar os usuários finais. / This study aims to introduce the reader to the influence of light on residential users, showing that the advancement of technologies throughout history and access to electric artificial lighting have provided greater comfort to the activities related to their homes. New technologies, more economically energetic, allowed access to greater amounts of light by users with different white light tones, allowing a wide choice, but may influence the production of the hormone melatonin, which regulates the biological clock, causing many disturbances. Fieldwork was carried out in residences, divided into two lines of reasoning, the first to be read in a sample of random households and the second based on a residence used as a model. However, in the latter case, the technologies employed were altered. In both cases measurements were taken in the living room in front of the television. These studies were based on the Circadian Stimulus method (Rea M.S., 2005, 2011), based on several laboratory studies, which demonstrated the influence of light on the production of melatonin, where it was used in the two adopted procedures. It is concluded that, although estimates of suppression levels found are low, technologies with higher color temperatures, meaning whiter lights, have higher inhibition rates and should be avoided, as well as the amounts of light practiced for residential environments must be carefully dimensioned. This work does not have a conclusive character but rather introduces a methodology that is still in the final phase of studies, but it can contribute to point out guidelines that have not been approached in the professional practice and are intended to guide end users
8

Análise das condições de iluminação das bibliotecas públicas municipais na cidade de São Paulo: diretrizes para um melhor aproveitamento da luz natural e redução do uso da iluminação artificial / The analysis on the lighting condition in public libraries in the city of São Paulo: guidelines for best natural lighting utilization and reduction of the artificial lighting use

Pinto, Sandra Regina 22 July 2008 (has links)
As bibliotecas públicas subordinadas à Secretaria Municipal de Cultura da cidade de São Paulo foram objeto de estudo desta pesquisa, que levantou e analisou os dados cadastrais das 60 bibliotecas, levantou e analisou os dados sobre iluminação natural, artificial e consumo de energia para este uso final de uma amostra de 15 bibliotecas e elaborou um projeto de retrofit para um caso. O levantamento dos dados cadastrais, dos dados sobre os sistemas de iluminação e consumo de energia foi realizado com o auxílio de fichas de campo desenvolvidas para sistematizar a coleta das informações durante as vistorias. Foram atualizadas as plantas de arquitetura, tabuladas as contas de energia e calculados os valores de consumo médio mensal, específico e desagregado, potência instalada, densidade de potência da iluminação e despesa com energia elétrica de 15 bibliotecas selecionadas como amostra do universo. Como um diagnóstico preliminar desta amostra, observou-se o predomínio de equipamentos ineficientes no sistema de iluminação artificial e o uso final em iluminação representou o maior percentual no consumo total de energia elétrica das bibliotecas. Para a elaboração do projeto de retrofit foi escolhida a biblioteca que apresentou o maior percentual de consumo desagregado em iluminação dentre os casos estudados e, para tanto, foi atualizado o levantamento energético e as análises sobre iluminação natural e artificial foram aprofundadas por meio de medições e simulações computacionais. As principais diretrizes que nortearam o desenvolvimento deste projeto foram a utilização de um sistema de iluminação artificial complementar à luz natural, a adequação dos valores de iluminância às necessidades visuais de cada ambiente e a adoção de equipamentos eficientes. A utilização de um sistema de iluminação artificial composto por equipamentos tecnologicamente eficientes possibilita a diminuição no consumo de energia numa edificação, sendo que reduções significativas podem ser alcançadas quando tal sistema for usado de maneira complementar à luz natural e com acionamento automático. Diante do repertório construído, foram definidas algumas diretrizes para o melhor aproveitamento da luz natural e redução do uso da iluminação artificial. / The public libraries controlled by São Paulo City Culture Bureau were the target of this survey, which raised and analysed registered data from 60 libraries, raised and analysed natural and artificial lighting data and the energy consumption for this latter purpose out of a sample of 15 libraries and prepared a retrofit project for one case. Raising registered data, lighting system data and energy consumption was carried out by using survey cards developed to systematise the data collection during the research. Architectural plans were updated, the energy bills were listed and calculated were the average monthly consumption values, specific and disaggregated, installed power, density of lighting power and electric energy expenditure of 15 selected libraries as a universe sample. As a preliminary diagnosis of such sample, we observed the predominance of inefficient equipments in the artificial lighting system and the final lighting use represented the major percentage of the libraries overall electric consumption. In order to prepare the retrofit project, we chose the library presenting the major percentage of disaggregated lighting consumption amongst all studied cases and, to such, we updated the energy survey and the analysis of natural and artificial lighting was deepened by means of measurements and computer simulation. The main principles guiding the development of this project were the application of an artificial lighting system complementary to daylighting, the adequacy of illuminance values to the visual needs of each room and the adoption of efficient equipments. The application of an artificial lighting system composed of technologically efficient equipments allows the reduction in the energy consumption in a building, being such reduction significant and achievable when that system is used in a complementary way with daylighting and with automatic operation. Before this so constructed repertory, we defined some guidelines for best daylighting utilization and reduction of the artificial lighting use.
9

Análise das condições de iluminação das bibliotecas públicas municipais na cidade de São Paulo: diretrizes para um melhor aproveitamento da luz natural e redução do uso da iluminação artificial / The analysis on the lighting condition in public libraries in the city of São Paulo: guidelines for best natural lighting utilization and reduction of the artificial lighting use

Sandra Regina Pinto 22 July 2008 (has links)
As bibliotecas públicas subordinadas à Secretaria Municipal de Cultura da cidade de São Paulo foram objeto de estudo desta pesquisa, que levantou e analisou os dados cadastrais das 60 bibliotecas, levantou e analisou os dados sobre iluminação natural, artificial e consumo de energia para este uso final de uma amostra de 15 bibliotecas e elaborou um projeto de retrofit para um caso. O levantamento dos dados cadastrais, dos dados sobre os sistemas de iluminação e consumo de energia foi realizado com o auxílio de fichas de campo desenvolvidas para sistematizar a coleta das informações durante as vistorias. Foram atualizadas as plantas de arquitetura, tabuladas as contas de energia e calculados os valores de consumo médio mensal, específico e desagregado, potência instalada, densidade de potência da iluminação e despesa com energia elétrica de 15 bibliotecas selecionadas como amostra do universo. Como um diagnóstico preliminar desta amostra, observou-se o predomínio de equipamentos ineficientes no sistema de iluminação artificial e o uso final em iluminação representou o maior percentual no consumo total de energia elétrica das bibliotecas. Para a elaboração do projeto de retrofit foi escolhida a biblioteca que apresentou o maior percentual de consumo desagregado em iluminação dentre os casos estudados e, para tanto, foi atualizado o levantamento energético e as análises sobre iluminação natural e artificial foram aprofundadas por meio de medições e simulações computacionais. As principais diretrizes que nortearam o desenvolvimento deste projeto foram a utilização de um sistema de iluminação artificial complementar à luz natural, a adequação dos valores de iluminância às necessidades visuais de cada ambiente e a adoção de equipamentos eficientes. A utilização de um sistema de iluminação artificial composto por equipamentos tecnologicamente eficientes possibilita a diminuição no consumo de energia numa edificação, sendo que reduções significativas podem ser alcançadas quando tal sistema for usado de maneira complementar à luz natural e com acionamento automático. Diante do repertório construído, foram definidas algumas diretrizes para o melhor aproveitamento da luz natural e redução do uso da iluminação artificial. / The public libraries controlled by São Paulo City Culture Bureau were the target of this survey, which raised and analysed registered data from 60 libraries, raised and analysed natural and artificial lighting data and the energy consumption for this latter purpose out of a sample of 15 libraries and prepared a retrofit project for one case. Raising registered data, lighting system data and energy consumption was carried out by using survey cards developed to systematise the data collection during the research. Architectural plans were updated, the energy bills were listed and calculated were the average monthly consumption values, specific and disaggregated, installed power, density of lighting power and electric energy expenditure of 15 selected libraries as a universe sample. As a preliminary diagnosis of such sample, we observed the predominance of inefficient equipments in the artificial lighting system and the final lighting use represented the major percentage of the libraries overall electric consumption. In order to prepare the retrofit project, we chose the library presenting the major percentage of disaggregated lighting consumption amongst all studied cases and, to such, we updated the energy survey and the analysis of natural and artificial lighting was deepened by means of measurements and computer simulation. The main principles guiding the development of this project were the application of an artificial lighting system complementary to daylighting, the adequacy of illuminance values to the visual needs of each room and the adoption of efficient equipments. The application of an artificial lighting system composed of technologically efficient equipments allows the reduction in the energy consumption in a building, being such reduction significant and achievable when that system is used in a complementary way with daylighting and with automatic operation. Before this so constructed repertory, we defined some guidelines for best daylighting utilization and reduction of the artificial lighting use.
10

If the world were so bright: artificial lighting at night impacts crayfish behavior and physiology

Jackson, Kelly M. 07 May 2019 (has links)
No description available.

Page generated in 0.1095 seconds