<p> The goal of this research is to establish a visual environment diagnostic model based on the occupant's physiological responses for detecting improper ambient lighting conditions, a major contributing factor to visual stress and work productivity in office workplace environments. The human body, as a biological mechanism, naturally minimizes the effects of ambient environmental stressors using its physiological autonomous nerve system. This system enables a human's pupils to dilate and contract, depending on visual sensations affected by the ambient lighting conditions. An extensive experiment using human subjects will be conducted in an environmental chamber on the University of Southern California campus. All parametric data including human pupil sizes and lighting parameters will be categorized by age and ethnic origin, to investigate and determine the most common features of pupil sizes per visual sensation among individuals. Lighting parameters, including illuminance (lux), luminance (cd/m2), and lighting-color-temperature (K), will be controlled and maintained for each volunteer subject based on his/her task-type (computer-based or paper-based), which is most typical in the current office environment. </p><p> This study will provide unique knowledge concerning how an occupant via his/her physiological signal, i.e. pupil size can interact with the visual (lighting) environment. The research outcome will be potentially applicable in reality to diagnose the lighting quality in workplace environments, and to integrate an occupant's pupil size information for the visual environmental controls.</p>

<p> The primary objective of this thesis is to evaluate the effects of torsion on the nonlinear seismic response of a thirteen-story reinforced concrete frame-wall structure with an asymmetric stiffness in plan. The NEHRP building structure, located in Berkeley, CA and previously designed by Andr&eacute; Barbosa, was modeled in ETABS and SAP2000 to perform several analyses. The models accounted for realistic cracked concrete section stiffnesses, expected material properties, and nonlinear plastic hinges. Due to limitations of ETABS in performing nonlinear dynamic time history analysis, the model was exported to SAP2000. An asymmetric lateral stiffness model was created by moving one of the shear walls from the center of the building toward the outside of the building. OpenSees was used to find the nonlinear hinge moment-rotation relationships. </p><p> Using a suite of seven ground motion record pairs, an essentially linear dynamic time history analysis was performed on the symmetric and asymmetric ETABS models. The SAP2000 models were used to perform a series of nonlinear static (pushover) analyses. Fully nonlinear, including material and geometric nonlinearity, time history analyses were performed on the SAP2000 models using the seven ground motion pairs, appropriately cut to shorter lengths to reduce the analysis run-time. In each analysis case, the results of the symmetric and asymmetric models were compared. Overall, the asymmetric model typically experienced torsional effects and larger displacement responses than the symmetric model. The more nonlinear the structure behaved, the more influence torsion had on the response of the model with asymmetrically-placed shear walls.</p>

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 148-152). Also available in electronic version.

<p>Heat transfer from building foundations varies significantly in all three spatial dimensions and has important dynamic effects at all timescales, from one hour to several years. With the additional consideration of moisture transport, ground freezing, evapotranspiration, and other physical phenomena, the estimation of foundation heat transfer becomes increasingly sophisticated and computationally intensive to the point where accuracy must be compromised for reasonable computation time. The tools currently available to calculate foundation heat transfer are often either too limited in their capabilities to draw meaningful conclusions or too sophisticated to use in common practices. This work presents Kiva, a new foundation heat transfer computational framework. Kiva provides a flexible environment for testing different numerical schemes, initialization methods, spatial and temporal discretizations, and geometric approximations. Comparisons within this framework provide insight into the balance of computation speed and accuracy relative to highly detailed reference solutions. The accuracy and computational performance of six finite difference numerical schemes are verified against established IEA BESTEST test cases for slab-on-grade heat conduction. Of the schemes tested, the Alternating Direction Implicit (ADI) scheme demonstrates the best balance between accuracy, performance, and numerical stability. Kiva features four approaches of initializing soil temperatures for an annual simulation. A new accelerated initialization approach is shown to significantly reduce the required years of presimulation. Methods of approximating three-dimensional heat transfer within a representative two-dimensional context further improve computational performance. A new approximation called the boundary layer adjustment method is shown to improve accuracy over other established methods with a negligible increase in computation time. This method accounts for the reduced heat transfer from concave foundation shapes, which has not been adequately addressed to date. Within the Kiva framework, three-dimensional heat transfer that can require several days to simulate is approximated in two-dimensions in a matter of seconds while maintaining a mean absolute deviation within 3%.

<p> The objective for this thesis is to outline a Performance-Based Engineering (PBE) framework to address the multiple hazards of Earthquake (EQ) and subsequent Fire Following Earthquake (FFE). Currently, fire codes for the United States are largely empirical and prescriptive in nature. The reliance on prescriptive requirements makes quantifying sustained damage due to fire difficult. Additionally, the empirical standards have resulted from individual member or individual assembly furnace testing, which have been shown to differ greatly from full structural system behavior. The very nature of fire behavior (ignition, growth, suppression, and spread) is fundamentally difficult to quantify due to the inherent randomness present in each stage of fire development. The study of interactions between earthquake damage and fire behavior is also in its infancy with essentially no available empirical testing results. This thesis will present a literature review, a discussion, and critique of the state-of-the-art, and a summary of software currently being used to estimate loss due to EQ and FFE. A generalized PBE framework for EQ and subsequent FFE is presented along with a combined hazard probability to performance objective matrix and a table of variables necessary to fully implement the proposed framework. Future research requirements and summary are also provided with discussions of the difficulties inherent in adequately describing the multiple hazards of EQ and FFE.</p>

Thesis (M. Arch.)--University of Hong Kong, 1996. / Includes special study report entitled: Towards a prototypical compact dwelling. Includes bibliographical references.

<p> With the advent of inexpensive computing and efficient power electronics, the load mix in commercial buildings has experienced a fundamental shift away from almost exclusively traditional alternating current (AC) loads toward primarily direct current (DC) loads&mdash;devices which use DC electricity either for end-use or as a power conditioning stage. Simultaneously, installations of DC distributed generation sources for commercial buildings, such as rooftop photovoltaic arrays, are accelerating. Despite this proliferation of DC devices, the basic design of building electrical distribution systems has changed very little in the past century: AC distribution remains the industry standard. The AC-DC electricity conversions required to connect DC sources and loads to the AC electric grid result in wasted energy. Partial replacement of AC distribution with DC distribution can improve overall building electrical energy efficiency; the result is a mixed AC-DC electrical distribution system. This dissertation develops a modeling framework, mathematical program, and global optimization algorithm which determine maximally energy efficient designs for mixed AC-DC building electrical distribution systems. The research approach precisely quantifies building electrical energy efficiency at a systems level, not simply the level of individual devices. The results of two case studies validate the power of the optimization algorithm and demonstrate that well designed mixed AC-DC building electrical distribution systems can achieve higher efficiency than either AC or DC distribution used alone.</p>

<p> Life cycle assessment (LCA) can aid in quantifying the environmental impacts of whole buildings by evaluating materials, construction, operation and end of life phases with the goal of identifying areas of potential improvement. Since buildings have long useful lifetimes, and the use phase can have large environmental impacts, variations within the use phase can sometimes be greater than the total impacts of other phases. Additionally, buildings are operated within changing industrial and environmental systems; the simultaneous evaluation of these dynamic systems is recognized as a need in LCA. At the whole building level, LCA of buildings has also failed to account for internal impacts due to indoor environmental quality (IEQ). The two key contributions of this work are 1) the development of an explicit framework for DLCA and 2) the inclusion of IEQ impacts related to both occupant health and productivity. DLCA was defined as &ldquo;an approach to LCA which explicitly incorporates dynamic process modeling in the context of temporal and spatial variations in the surrounding industrial and environmental systems.&rdquo; IEQ impacts were separated into three types: 1) chemical impacts, 2) nonchemical health impacts, and 3) productivity impacts. Dynamic feedback loops were incorporated in a combined energy/IEQ model, which was applied to an illustrative case study of the Mascaro Center for Sustainable Innovation (MCSI) building at the University of Pittsburgh. Data were collected by a system of energy, temperature, airflow and air quality sensors, and supplemented with a postoccupancy building survey to elicit occupants&rsquo; qualitative evaluation of IEQ and its impact on productivity. The IEQ+DLCA model was used to evaluate the tradeoffs or co-benefits of energy-savings scenarios. Accounting for dynamic variation changed the overall results in several LCIA categories&mdash;increasing nonrenewable energy use by 15% but reducing impacts due to criteria air pollutants by over 50%. Internal respiratory effects due to particulate matter were up to 10% of external impacts, and internal cancer impacts from VOC inhalation were several times to almost an order of magnitude greater than external cancer impacts. An analysis of potential energy saving scenarios highlighted tradeoffs between internal and external impacts, with some energy savings coming at a cost of negative impacts on either internal health, productivity or both. Findings support including both internal and external impacts in green building standards, and demonstrate an improved quantitative LCA method for the comparative evaluation of building designs.</p>

Thesis (M.Arch.)--University of Hong Kong, 1996. / Includes special study report entitled : Towards a prototypical compact dwelling. Includes bibliographical references. Also available in print.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Leaf v does not exist therefore pre-paging is misnumbered. Vita. Includes bibliographical references (leaves 256-262). Also available on the Internet.