With the rapid development of wireless networking technology and the great growth of the service demand, accurate location estimation of a mobile station (MS) in an indoor wireless system has gained considerable attention. Since most wireless communication systems used for indoor position location may suffer from dense NLOS propagation error, which leads to a severe degradation of position accuracy. In this thesis, we propose a hybrid TOA/RSSI wireless positioning technique for indoor UWB systems to gain favorable position accuracy, by using the fine resolution of UWB signals, geometrical feature of cell layout, the path loss model and the received signal strength, based on the time of arrival (TOA) range measurements. The algorithm induces the objective function from the geometrical relationships of the base stations (BSs) and TOA range circles, and utilizes the received signal strength and pre-estimated path loss model, which should be well approximating the propagation conditions, to discriminate between LOS or NLOS range measurements and define the weight factors used to describe how credible TOA range measurements are and take effect on the objective function during the location calculating process. Simulation results show that the positioning accuracy of the hybrid TOA/RSSI method is much higher than that of other positioning methods under different distributed NLOS errors.

No description available.

No description available.

The projects goal was to make an already existing indoor positioning system useful forthe average smartphone user. This was achieved by creating an Android applicationwhich, along with a running server, continuously presents the user with all the currentneeded information. It uses the graphics engine andEngine to create the graphical userinterface. The application was created in the development environments Eclipse andAndroid Studio.

A study on the potential of daylighting as a source of indoor lighting in Malaysian buildings is described. Not much work has been done on daylighting in Malaysia, due to several factors. Firstly, local daylight data is unavailable and secondly, research in daylighting design is relatively new. This work is therefore aimed at providing a solid foundation in daylighting knowledge and to contribute towards the development of deSign tools and strategies for buildings in a hot, humid climate, in particular Malaysia. The work began with a survey of traditional and modern buildings to identify old and new daylighting techniques. From the daylighting point of view, recently built buildings in general, are not designed for the tropics. The bioclimatic approach was used to identify the passive strategies to keep Malaysian buildings thermally comfortable for the occupants. The Model Year Climate accurate hourly data for 8 climate parameters were produced by statistical analyses from a database of 21 years of meteorological data. A field study to determine the thermal comfort conditions of young persons in a normal working environment was also carried as part of the bioclimatic analyses. From the results of the three studies, a strategy was formulated to create a low-energy yet thermally comfortable building environment for the hot-humid region by integrating daylighting in the building design through the size of window openings and types of shading devices. The prevailing sky type in the Klang Valley was determined using solar irradiation and cloud cover data. The sky type was identified, and confirmed by four identification techniques, as predominantly intermediate. As daylight and solar irradiation share similar physical properties, hourly daylight data were modelled using solar irradiation data and luminous efficacy values. An artificial sky was designed and constructed to conduct daylighting experiments using architectural scale models. The correlation coefficient of the luminance produced by the sky simulator as compared to the intermediate sky luminance model was 0.996. This study focussed on sidelighting, which is the most common daylighting strategy in Malaysia. The daylighting performance of several window opening sizes ranging from 10% up to 40% window-to-wall ratio and several types of shading devices were investigated using the Daylight Factor Method. A suitable architectural scale model of a basic room with one removable wall, on which the fenestration systems were attached, was used for the investigations. The optimum window opening size was found to be 25% where daylight is enhanced and energy consumption for cooling load is reduced. The best shading device tested for buildings in the Malaysian climate was found to be a sloped shading device integrated with a horizontal light shelf. This device has the capability to reduce excess lighting while maintaining the required daylight levels in a normal working environment as recommended by the Malaysia Guidelines for Energy Efficiency in Buildings. The results of the daylighting performance of the fenestrations were used together with modelled exterior illuminance data to produce several daylighting design tools. Graphical tools produced to aid architects include iso-OF charts, isolux charts or daylight footprints while look-up tables and nomographs were produced for engineers. The NORMA algorithm was used to calculate the cooling loads of a simple building to demonstrate the possible energy savings as a result of applying the above daylighting strategies. It was found that at least 10% of energy could be saved by integrating daylighting in Malaysian buildings while maintaining acceptable indoor thermal comfort criteria for young Malaysians.

No description available.

The design process of HVAC (Heating, Ventilation and Air Conditioning) systems is based upon selecting suitable components and matching their performance at an arbitrary design point, usually determined by an analysis of the peak environmental loads on a building. The part load operation of systems and plant is rarely investigated due to the complexity of the analysis and the pressure of limited design time. System simulation techniques have been developed to analyse the performance of specific commonly used systems: however these 'fixed menu, simulations do not permit appraisal of hybrid and innovative design proposals. The thesis describes research into the development of a component based simulation technique in which any system may be represented by a network of components and their interconnecting variables. The generalised network formulation described is based upon the engineer's schematic diagram and gives the designer the same flexibility in simulation as is available in design. The formulation of suitable component algorithms using readily available performance data is discussed, the models developed being of a 'lumped parameter' steady state form. The system component equations are solved simultaneously for a particular operating point using a gradient based non-linear optimisation algorithm. The application of several optimisation algorithms to the solution of RVAC systems is described and the limitations of these methods are discussed. Conclusions are drawn and recommendations are made for the required attributes of an optimisation algorithm to suit the particular characteristics of HVAC systems. The structure of the simulation program developed is given and the application of the component based simulation procedure to several systems is described. The potential for the use of the simulation technique as a design tool is discussed and recommendations for further work are made.

In the warm humid tropical climate of Bali, Indonesia, overheating and high humidity influence occupants' comfort, indoor climate and the comfort of their homes, both directly and indirectly. The traditional way to deal with these problems, using natural ventilation, was ecologically sound and acceptable. However, development of tourism in Bali has had a positive impact on people's earning, causing cultural pressure, migration and a rapid rise in the urban population, as well as increasing housing demand. In urban areas, the methods of climate modification have moved away from natural ventilation, and comfort is now more often achieved by installing air conditioning. This has caused increasing energy use and had economic impact. As world-wide energy consumption will continue to increase, the use of more energy will have more impact on global warming. In these circumstances, energy efficiency is paramount, particularly in the dwelling designs for new housing development in Indonesia. The study focuses on the design of a thermally comfortable dwelling in the warm humid climate of Bali, Indonesia, with emphasis on the energy efficiency of the naturally ventilated and air-conditioned dwelling. Using a computer program and energy conservation strategies, a dwelling design was simulated. A model dwelling was adopted from a standard house type for people on a middle class income, based on the family size of a couple with two children. Such units are built by the National Housing Authority of Indonesia. A comprehensive study of the computer-simulation outcomes, survey research, previous works undertaken and literature reviews were carried out, to develop a thermally comfortable dwelling design. This new thermally efficient dwelling design was simulated to draw the final conclusions of the research. The research discovered that the combination of both natural ventilation and air conditioning, integrated with the combined design of a compound-compact dwelling, are an intelligent response to the thermal comfort performance problems of a dwelling in the warm humid climate and architecturally adaptable to the culture of Bali. The study found that a combination of natural ventilation with air conditioning which is only used when necessary, coupled with insulation and shading devices, can significantly reduce energy consumption and achieve adequate thermal comfort. In this respect, however, architectural design should come first, and be considered before an engineering solution. The reasons are that architectural solutions are more robust, and has a long duration of applicability, while the technology is perhaps the opposite, being prone to mechanical failure. When a less compact dwelling is designed, increased use of natural ventilation can be achieved. The use of airtight construction, insulation in the building envelope and shading devices are effective ways of reducing the air-conditioning load.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M. Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 146-153).