This thesis presents the applications of a series interconnection scheme for small distributed generation (DG) systems in distribution networks. The concept uses one set of voltage source converter (VSC) to control the injected voltage magnitude and phase angle for power injection and voltage sag mitigation. Through an energy storage device and the VSC, DG outputs vary concurrently with the line loading and provide load leveling functions. Under voltage sag situations, it provides missing voltages to effectively deal with power quality problems. Due to its series connection characteristic, it is convenient in preventing islanding operation and good for fault current limiting. The concept is suitable for locations where the voltage phase shift is not a major concern. Due to the use of only one set of converter, it is economic for customer site distributed energy resource applications and its control strategy would depend on the types of load connected.

Ultra Wideband (UWB) signal can offer an accurate location service in wireless sensor networks because its high range resolution. Target tracking by multiple sensors can provide better performance, but the centralized algorithms are not suitable for wireless sensor networks. In additional, the non line of sight (NLOS) propagation error leads to severe degradation of the accuracy in location systems. In this thesis, NLOS identification and mitigation technique utilizing modified biased Kalman filter (KF) is proposed to reduce the NLOS time of arrival (TOA) errors in UWB environments. We combine the modified biased Kalman filter with sliding window to identify and mitigate different degree of NLOS errors immediately. In order to deal with the influence of inaccurate NLOS angle of arrival (AOA) measurements, we also had a discussion on AOA selection and fusion methods. In the distributed location structure, we used the extended Information filter (EIF) to process the formulated time difference of arrival (TDOA) and AOA measurements for the target positioning and tracking. Instead of using extended Kalman filter, extended Information filter can assimilate selected AOA easily without dynamic dimensions. The sensors are divided into different groups for distributed TDOA/AOA location to reduce computation and then each group can assimilate information from other groups easily to maintain precise location. The simulation results show that the proposed architecture can mitigate NLOS errors effectively and improve the accuracy of target positioning and tracking from distributed location and data fusion in wireless sensor networks.

A vector form intrinsic finite element method ( plane frame element ) is developed and applied to study the dynamic responses of offshore template platform under wave force. The horziontal, vertical and rotational motions at each node in the finite element model also were analyzed by the developed solution procedure of offshore structures. Besides, this paper also discussed the application of viscoelastic dampers on the offshore structures. A design for the dampers incorporated in the template structure were presented, and dynamic analyses were carried out to observe the effect of the vibration mitigation on the structures .

Earthquakes in Turkey, among all natural disasters claim the highest losses in terms of human lives, material and economic assets. Most of the lives are lost within the collapsed buildings, and most of the material and economic losses are again directly related to the functional capacities of the building stock. The method of risk assessment in the existing building stock is therefore an essential step in the maintenance of safer urban environments. Analysis of risks in the building stock is usually claimed to demand surveys of engineering studies. Yet risk determination studies by planners could prove not only a more comprehensive approach, but less time consuming and cheaper. As carried out by engineers, most of safety studies in the building stock are directly related with estimating the probability of collapse and damage in individual buildings. It is necessary to recognize the need for analysis of the building stock not only in terms of structural robustness, but as part of a mitigation plan, taking into consideration all sources of hazards and the urban pattern, densities, landuse, forms of ownership, social features, management capacities, and local opportunities. Risky buildings determined by a simple set of criteria within a comprehensive planning context are comparatively explored in this study to observe the level of fit with those determined by engineering surveys. The case of Fatih District in Istanbul provides an opportunity to carry out comparative analyses. It indicates that a &lsquo / perfect fit&rsquo / can not be achieved if for nothing but due to the disregard of multi-hazard areas, hazardous activities and other vulnerabilities like timber buildings other than reinforced concrete in the district by the engineering survey. Several trials indicated that there is a trade-off between ratio of fit and the total volume of relative vulnerability assumed. Ratios like 70% or more could make the planning approach a preferable method owing to its nature of least time-consuming and costly alternative in the determination of what constitutes risk in any urban area. Ultimate assessment could be made with the occurance of the earthquake itself.

During the past two decades, community-based hazard mitigation (CBHM) has been newly proposed and implemented as an alternative conceptual model for emergency management to deal with disasters comprehensively in order to curtail skyrocketing disaster losses. Local community members have been growingly required to share information and responsibilities for reducing community vulnerabilities to natural and technological hazards and building a safer community. Consequently they are encouraged to join local mitigation programs and volunteer for collective mitigation action, but their contributions vary. This research examined factors associated with Tulsa Project Impact partners?? contributions to collective mitigation action. In the literature review, self-interest and social norms were identified and briefly discussed as two determinants to guide partners?? behavior by reviewing game theoretic frameworks and individual decision-making models. Partners?? collective interest in building a safer community and feelings of obligation to participate in collective mitigation action were also considered for this study. Thus, the major factors considered are: (1) collective interests, (2) selective benefits, (3) participation costs, (4) norms of cooperation, and (5) internalized norms of participation. Research findings showed that selective benefits and internalized norms of participation were the two best predictors for partners?? contributions to collective mitigation action. However, collective interests, participation costs, and norms of cooperation did not significantly influence partners?? contributions.

Wetland-based treatment systems are often implemented as a method to remove unwanted substances from contaminated groundwater. Wetlands are effective due to the high biological activity that naturally takes place in the rhizosphere and soil. In support of a demonstration surface wetland system at a site in Columbus, Georgia, laboratory-scale wetland systems were designed to study the effect of different carbon sources and their biodegradability, COD:N ratio and temperature on the rate and extent of nitrate reduction of nitrate-bearing groundwater. Nitrate reducing bacteria are ubiquitous in surface and subsurface wetlands but a major limiting factor for these systems is carbon availability. Two major carbon sources were investigated in both continuous-flow and batch systems: a natural source, hay and a commercial source, MicroC GTM, a concentrated carbohydrate mix. Between these two carbon sources, the nitrate removal rate was not significantly different as long as sufficient biodegradable carbon was provided. The effect of both hydraulic retention time (HRT) and COD:N ratio on nitrate removal were investigated in continuous-flow systems. The specific nitrate removal rate in open to the atmosphere batch reactors was estimated at 0.55 mg N/mg biomass VSS-day. The effluent nitrate concentration in a continuous-flow system maintained with an HRT of 5 days at room temperature (22 to 23°C) was less than 3 mg nitrate-N/L. The COD:N ratio was kept at 6:1 for the majority of the experiments (approximately twice the theoretical requirement) to ensure sufficient carbon loading. Lower COD:N ratios of 5, 4, 3, 2, 1, and 0.5 were also investigated in the continuous-flow system and the minimum required carbon loading to achieve an effluent nitrate concentration below 10 mg N/L for an influent groundwater nitrate concentration between 65 and 70 mg N/L was determined to be 5:1 COD:N. The effect of temperature on the nitrate removal rate was also investigated at 22, 15, 10 and 5°C. As expected, the rate of nitrate reduction decreased with the decrease in temperature, especially below 10°C. Overall, the surface wetland is a feasible solution to treating nitrate-bearing groundwater even at relatively low ambient temperature values, provided that sufficient, biodegradable carbon is present.

We study timing effects of carbon mitigation and solar radiation management (SRM) policies for correlated pollutants, CO₂ and SO₂. We show that national levels of carbon and sulfur emissions quotas and SRM implementation are positively correlated with each other. First-mover advantages exist when deciding both carbon quotas and SRM levels. Moreover, we use an example to illustrate that if international equity is considered, governments would be willing to choose SRM levels before carbon quotas since it yields higher payoffs and less acid rain and droughts damages. This timing was neglected by all previous theoretical economic models on geoengineering.

Diss.--New Delhi Jawaharlal Nehru Univ.

Thesis (M.A.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 79-91). Also available via the World Wide Web.

Thesis (Ph. D.)--Universität St. Gallen, 2001. / "Dissertation Nr. 2547." Includes bibliographical references (p. 231-270).