Typescript (photocopy).

Call number: LD2668 .T4 1985 H87 / Master of Science

Concerns about global warming are increasing, hence, the urgency to cut carbon emissions. Reducing energy consumption, including lighting energy, is seen as the primary solution. Yet, solving the environmental factor should not come at the cost of other pillars of sustainable development. Rather, maximizing the total value of the building should be the focus. Maximizing value in the context of lighting entails improving the quality of the lighting. This study has investigated how lighting simulation could help in achieving better lighting quality. The aim of the thesis was defined as to understand the underlying architecture of lighting simulation and obtain an overview of its characteristics and applications as well as to study the use of current simulation tools. The theoretical background of lighting simulation (in the domain of Systems Engineering) was reviewed from the literature. This revealed the missing and imperfect links in the solution-to-value chain. The thesis suggests the use of a new base metric, Retinal Illuminance Map, as a solution, which in combination with black box simulation of a visual system can help repair this incomplete chain. The study of the current lighting simulation tools (Paper 1) revealed that illuminance-based metrics, luminance-based metrics, daylight availability metrics, and glare indexes are the most available performance metrics in existing lighting simulation tools. Based on usability, acceptability, availability, and previous references in the literature six software programs (Radiance, DAYSIM, Evalglare, DIALux, VELUX, and VISSLA) were selected and compared. It was found that no single tool could meet all the needs of a designer, hence, simulation tool(s) should be selected (or combined) according to the requirements of project goals and the stage of design. Building on these studies, applications of lighting simulation were identified and compiled in relation to different aspects, including performance metrics, stages of design, optimization, model integration, BIM, and parametric modeling. To obtain first-hand information about lighting designers’ experience, an online survey was conducted in Sweden (Paper 2). The results showed that lighting simulation programs were widely (90%) used in Sweden for analysis and/or rendering purposes. The majority of lighting designers considered both daylight and artificial light in their design. Factors such as ease-of use, simulation time and training had more weight than accuracy and the diversity of metrics in practitioner’s eyes. Surrogate modeling was identified as a solution for speeding up simulation time, which would also enable exploration of design solution space especially in the early design stage.

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Lighting simulation contribute readily to the synthesis of high performance lighting designs. Unfortunately there exist several issues impeding the pervasive use of lighting simulation, including: Most of the time in preparing lighting simulations is spent towards the input of existing but non-interoperable information between different tools. Lighting simulation tools do not complement integrated building design processes where the design solution is progressively developed in multiple disciplines concurrently; lighting simulation tools require design information (attributes) that may not yet be defined, and is non-interoperable with other tools. . Disparate tools with vastly different technical approaches available for different stages of the building design process do not allow consistent or meaningful performance comparisons between design versions, and similarly makes design performance progress tracking between design versions difficult. Lighting simulation tools provide radiance and irradiance values as simulation results, and much time and manual effort is required to process these results into operative information, information that is directly applicable in making design decisions. Lighting simulation tools employ outdated rendering techniques that are inadequate in evaluating highly-reflected irradiance, a typical feature in high performance building designs. While there remain other shortcomings in lighting simulation tools as identified by contemporary research3, the issues above relate closely to the overall effort and time-cost factors attributed to using simulation tools, which has been consistently identified as obstacles towards using simulation tools. This research seeks to reduce the effort and time-cost required to conduct lighting simulation by addressing the issues above. Case studies of actual design scenarios are used to establish quantitatively the effort and time costs baselines for comparison. The effort and time reduction goal is structured as the following objectives in a new lighting design support tool: Reduce the time and effort to set up and conduct lighting simulation by using interoperable information (building information models) from design modeling tools. Complement integrated design processes by supporting design models of varying completeness5, in a format that is interoperable with tools from other disciplines in the design team. All information, including assumptions, must be consistent across all disciplines. Provide ability to use performance metrics and consistent technical approaches throughout design stages, regardless of completeness of design model. Provide operative information with minimum user effort. Implement a first principle-based rendering technique that handles high performance building designs well, and produce simulation results within reasonable time constraints. By meeting these objectives, the new lighting design tool is able to automate much of the previously manual, time-consuming, and disparate efforts in lighting simulation, thus reducing the effort and time-cost. By sharing interoperable information with other tools across the design team, the new lighting design tool is integrated. The new tool is also scalable in being able to support models of varying completeness throughout all design stages.

D. Tech. Electrical Engineering. / Aims of this study is to develop a residential customers' lighting profile ANFIS-based model. This model is expected to address lighting load usage estimation in relation to the dynamic occupancy presence in a residential dwelling, which will take into account the climatic condition (natural lighting) of such an environment (e.g. South Africa) and its income. The objectives are as follows: 1. Develop an ANFIS-based residential lighting load profile model for middle income, low income and high-income earners. 2. Error reduction in residential lighting demand profile model. Performance evaluation and validation of the model using correlation and trend analysis, regression model, South Africa power utility application lighting program, non-weighted approach and comparison with other research studies (methodology).3. Reduction in / or elimination of repeated models for occupant presence and assumptions that residences are occupied at certain periods. 4. Derive meaning from complexities (behavioural trends) associated with lighting usage and extract patterns in such circumstances.

La simulation des réflexions lumineuses multiples à l'intérieur d'un environnement nécessite de résoudre une intégrale de premier ordre, récursive infinie, pour laquelle il n'existe pas de solution analytique dans le cas général. Certaines méthodes permettent de donner une solution théorique exacte, mais avec des temps de calcul trop important pour espérer produire plusieurs images par seconde dans un avenir proche. De nombreuses méthodes permettent de réaliser ces calculs de manière plus rapide, mais elles reposent sur des approximations dont les effets sont souvent visibles sur les images produites. Notre objectif est de proposer des solutions permettant de réduire les erreurs de calculs en exploitant deux approches complémentaires : (i) une homogénéisation des termes de l'équation de manière à la résoudre seulement à l'aide de quelques opérateurs simples ; (ii) la prise en compte précise des informations de visibilité pour réduire le biais des méthodes reposant sur une estimation de densité. A terme, notre objectif est de diminuer le coût des requêtes de visibilité de nos deux contributions. Pour cela nous envisageons notamment d'introduire des calculs hiérarchiques de visibilité de façon à amortir le coût global des requêtes. / Simulating light transfer within a virtual environment requires to solve a first order, infinite recursive integral, that unfortunately doesn't have any solution in general cases. Though theoretically exact solutions exist, their computing time is not adapted to real-time rendering in a near future. Many methods have been proposed for accelerating these computations, but they rely on approximations that often produce visible artifacts on the resulting images. Our goal is to propose some new solutions that can reduce biases with two complementary approaches : (i) a new homogeneous representation of each term of the equation can be used to resolve it using only simple operators ; (ii) considering precise visibility information in order to reduce bias of methods that rely on density estimation. On the long range, we aim at reducing visibility requests costs of each contribution. For that purpose, we particularly plan to introduce hierarchical visibility computations so as to amortize queries cost.

Effective daylighting can substantially reduce the energy use and greenhouse gas emissions of commercial buildings. Daylight is also healthy for building occupants, and contributes to occupant satisfaction. When productivity improvements are considered, effective daylighting is also highly attractive financially. However, successful daylighting of sub-tropical buildings is a very difficult task, due to high direct irradiances and excessive solar shading. A device was created that combined effective solar shading and efficient daylight redirection. The micro-light guiding shade panel achieves all objectives of an optimal daylighting device placed on the façade of a sub-tropical, high rise office building. Its design is based on the principles of non-imaging optics. This provides highly efficient designs offering control over delivered illumination, within the constraints of the second law of thermodynamics. Micro-light guiding shade panels were constructed and installed on a test building. The tested devices delivered daylight deep into the building under all conditions. Some glare was experienced with a poorly chosen translucent material. Glare was eliminated by replacing this material. Construction of the panels could be improved by application of mass-manufacturing techniques including metal pressing. For the micro-light guiding shade panel to be utilised to its full potential, building designers must understand its impact on building performance early in the design process. Thus, the device must be modelled with lighting simulation software currently in use by building design firms. The device was successfully modelled by the RADIANCE lighting simulator. RADIANCE predictions compared well with measurements, providing bias generally less than 10%. Simulations greatly aided further development of the micro-light guiding shade panel. Several new RADIANCE algorithms were developed to improve daylight simulation in general.

In the article Language of Lighting, Schielke (2019) states creation of visual material as the most efficient way to reproduce design related solutions. According to Self (2018), to fully summarize a lighting solution in words prove to be insufficient when the receiver of the information is not able to visualize the results of the design. Progress has been made in understanding how visualizations are used as a driving force to mediate solutions, although knowledge of the everyday usage is still deficient. The purpose of the study is to examine the use of visualizations in the lighting industry, through the process of architectural lighting projects. To understand the importance of visual material and the implemented tools used to create these, the study is based on the experience of seven active consults and project leaders in the business of lighting and architecture. By applying qualitative interviews, a collection of empirical data could be sampled and analyzed to answer the two research questions of this study, which focuses on techniques used for visualizing lighting concepts and the basis for the choices of techniques. The results clearly suggest that the execution of visualizations depends strongly on available resources. However, the respondents stated they were rarely involved in projects where sketching has been done by hand and instead referred to digital software products as a more valuable medium. Presenting well elaborated visualizations has been recognized as one of the most efficient ways to persuade the costumer, as well as including elements beyond lighting that is of importance for each individual costumer. However, this aspect should be considered cautiously since it tends to create false representations of the final results.  Although several aspects are of great significance in the process of creating visualizations to represent the chosen project, all the respondents agreed that a communication between the client and other parts involved are crucial for a project to be successful. To avoid unappreciated consulting hours, responsible designers need to understand demands and desires of the client and produce the amount of visual material necessary – leading back to the importance of communication. / I artikeln Language of Lighting skriver Schielke (2019) att visuell representation står som det mest effektiva tillvägagångssättet för att presentera designrelaterade lösningar. Enligt Self (2018) innebär belysning ofta stora svårigheter när lösningar förmedlas verbalt, då mottagaren sällan besitter förmågan att kunna bilda sig en tydlig bild av designvalen. Framsteg har gjorts kring användandet av belysningsrelaterade visualiseringar även om kunskaper kring vardagligt användande är begränsade. Syftet med denna studie är att undersöka användandet av visualiseringar ute bland belysningsföretag i branschen och hur dessa implementeras i designprojekt. Erfarenheter har samlats från sju konsulter och projektledare, med bakgrund inom ljusdesign och arkitektur, för att bättre förstå vikten av visuellt material samt de verktyg som används för att framställa dem. Genom användandet av kvalitativa intervjuer har empiriska data kunnat utvinnas och analyseras för att svara på studiens två frågeställningar som fokuserar på tekniker som används vid visualisering av belysningskoncept samt vad val av teknik baseras på.  Resultaten antyder att skapandet av visualiseringar delvis beror på tillgängliga resurser. Handritade skisser används sällan då digitala verktyg anses vara mer användbara och värdefulla vid projektering. Genomarbetade visualiseringar förekommer alltmer och ses nu som ett av de mest effektiva sätten att sälja in projektidéer till beställare. Visualiseringar gör det även möjligt att inkludera designelement bortom belysning vilket också kan vara av kundintresse och säljande faktor. Det är dock viktigt med aktsamhet för att inte ge en missvisande representation av det slutliga resultatet. Även om aspekterna för att producera genomtänkta och tydliga visualiseringar är många kunde samtliga deltagare enas om att strategin bakom ett framgångsrikt projekt ligger i att upprätthålla god kommunikation, både med kund och samtliga övriga involverade parter. För att undvika för många arbetstimmar gäller det även att designers är medvetna om kundens önskemål och att krav på visuellt material motsvarar behovet – vilket leder tillbaka till vikten av god kommunikation.

This is a study of computer technology's impact on the theatrical design process. The tools of communication provided by technology were studied, and an analysis was conducted in the classroom of Digital Rendering, Digital Rendering Videos, and 3d CADD. After-wards, these tools were applied to an actual production of West Side Story where, with the addition of 3d light simulation software, the tools were used to communicate the design ideas from the lighting designer to the director. The goal of this process was to provide a 'real to life' virtual representation of the show to the director with the least amount of confusion. An additional goal was to test the limits and functions of the software; trying to learn all the benefits that could be provided to the process of mounting a theatrical production.