This study analyzes the economic and geographic effects of alternative locations on risky investment decisions in a probabilistic framework. Historically, alternative locations for multi-million dollar investments are often evaluated with deterministic models that rely on expected values or best case/worst case scenarios. Stochastic simulation was used to estimate the probability distribution for select key output variables, including net present value (NPV), of a proposed biomass to ethanol production facility in three alternative regions in Texas. The simulated NPV probability distributions were compared using Stochastic Efficiency with Respect to a Function (SERF) to predict the location preference of decision makers with alternative levels of risk aversion. Risk associated with input availability and costs were analyzed for the proposed plant locations so each location resulted in different levels of economic viability and risk that would not have been observed with a traditional deterministic analysis. For all analyzed scenarios, the projected financial feasibility results show a positive NPV over the 16 year planning horizon with a small probability of being negative. The SERF results indicate the Central Region of Texas is preferred for risk averse decision makers compared to the Panhandle and Coastal Bend Regions. Risk premiums were calculated for the alternative locations and are consistent for all risk averse decision makers, indicating the ranking of alternative locations are robust. Positive community impacts and sensitivity elasticities for key variables were estimated in the model. The estimated positive economic gains for the local economy are quite large and indicate locating a production facility in the region could substantially impact the local economy. The calculated sensitivity elasticities show ethanol price, ethanol yield, and hydrogen price are the three variables that have the greatest affect on the feasibility of a biomass to ethanol production facility.

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 173-183).

Impedance-based methods are used to locate faults on distribution systems because of their simplicity and ease of implementation. These methods require fault voltage and current data along with the positive- and zero-sequence line impedance values (in ohm per unit length) to estimate the reactance or distance to fault location. Inaccuracies in line impedance values, which arise from circuit model errors, have an adverse impact on fault location estimates of the impedance-based methods. Measurement errors in current and voltage transformers can also lead to inaccuracy in estimation. Further, all methods use simplistic models to represent the system load. The load in a practical distribution system does not conform to the oversimplified models leading to errors in estimation of fault location. This thesis presents sensitivity analysis of four impedance-based methods. It focuses on the Takagi, positive-sequence reactance, loop reactance and balanced-load methods. Amongst these four methods, the first three are commonly used for fault location. The fourth method was developed as a part of this work. The objective of sensitivity analysis is to study and quantify the effect of circuit model, measurement and load model errors, on the fault location estimates of the four methods. The results of this analysis are used to establish upper and lower bounds on the estimation errors for each method. The analysis begins with creation of a baseline case using a modified version of the IEEE 34 Node Test Feeder. All the methods estimate the reactance to fault location as a part of this analysis. The baseline case uses accurate line impedances and measurement values in the four methods. The fault location estimates for this case serve as a means of comparison for all subsequent analyzes. Secondly, various circuit model errors are introduced while computing the line impedance values. These errors include inaccurate modeling of four parameters viz. phase conductor distances, conductor sizes, phase to neutral conductor distances and earth resistivity. The erroneous line impedance values, which arise from these circuit model errors, are used in the four methods. The resultant location estimates are compared with those for the baseline case. It is observed that modeling errors in earth resistivity can cause estimation errors of 2% to 5% in the Takagi and positive-sequence reactance methods. These errors can be positive or negative depending upon whether the modeled earth resistivity value is more than or less than the accurate value. The effect of inaccurate modeling of the other three parameters is marginal. Additionally, the Takagi and positive-sequence reactance methods assume line impedances to be uniform while estimating fault location. Although this assumption is a type of circuit model error, it does not lead to significant errors in estimation. The loop reactance and balanced-load methods are insensitive to circuit model errors as they do not use line impedance values while estimating reactance to fault location. The next part is analysis of effect of measurement errors on fault location estimates. Ratio and phase angle errors are deliberately introduced in the current and voltage transformers and the erroneous measurements are used to conduct fault location. This causes 5% to 6% errors in estimation for the Takagi and positive-sequence reactance methods. These estimation errors can be positive or negative depending upon the magnitude of the CT and VT ratio errors and the sign of the phase angle errors. For the loop reactance method, erroneous measurements introduce 8% to 30% errors in fault location. This indicates that the loop reactance method is highly sensitive to measurement errors. The balanced-load method is moderately sensitive and experiences 6% to 7% errors in fault location estimates. Lastly, the effect of load current on fault location estimates is analyzed. When the Takagi and positive-sequence reactance methods are used on a heavily loaded system, they estimate fault location with an error of 5% to 8%. The loop reactance method is severely affected by the level of load current in the system. This method can estimate fault location with nearly 100% accuracy, on a lightly loaded system. However, the estimation errors for this method increase significantly and are in the range of 15% to 30%, as load current in the system increases. In case of the balanced-load method, unbalanced, heavy loads can cause estimation errors of 7% to 25%. The combined effect of all the error sources is taken into account by creating a confidence interval for each method. For the Takagi and positive-sequence reactance methods, the actual fault location can be expected to lie within ±10% of the estimated value. The fault location estimation error for the loop reactance and balanced-load methods is always positive. The actual reactance-to-fault is within -30% of the value estimated by these methods. / text

published_or_final_version / Housing Management / Master / Master of Housing Management

The Hong Kong government has dedicated considerable resources to study and test the viability of office decentralization within the city since the 1980s, with objectives to achieve more sustainable industry spatial patterns and to relieve the Central Business District (CBD)from pressures created by high density of establishments and employment. Policies encouraging firm relocation from CBD areas to other office nodes have been implemented, and it was believed that the construction of new railway lines would facilitate such decentralization policies. In addition, a review of literature suggests that decentralization seems to be an inevitable trend in the evolution of a city. In particular, it was proposed by Smith & Selwood (1983) that decentralization could be industry-selective. With this background, this research aims to examine whether industries in Hong Kong have actually exhibited decentralizing spatial patterns from the period 1995 to 2010and to compare trend of changes in spatial patterns among different industries. Four industries were selected as the target of study, which are (1) finance and insurance, (2) professionals services, (3) real estate, and (4) import/export, wholesale and retail trades. Their employment and establishment data at Tertiary Planning Unit (TPU) level were obtained from the Census and Statistics Department and processed. Through the use of spatial tools, it was found that the real estate industry experienced most rapid trends of decentralization, both in establishment and employment. The other industries were less obviously decentralized; for the finance and insurance industry and the import/export, wholesale and retail industry, there even appeared indicators of stronger concentration in the study period. These findings provide strong support for future relocation policies to be industry-oriented. Another important finding is that for all industries in all study years, employment distribution tends to be more centralized than establishment distribution, which suggests that decentralizing people may be harder to achieve than decentralizing offices. It is thus envisaged that in the future, government policies regarding traffic management need to complement decentralization policies in order to alleviate transportation pressure in Hong Kong’s CBD area. / published_or_final_version / Transport Policy and Planning / Master / Master of Arts in Transport Policy and Planning

Not available / text

5 pp. / As long term investments, trees are expected to provide benefits for extended periods of time, usually decades. Trees planted in locations where they cannot survive or where they create problems rarely stay in place for any length of time. Trees experiencing shortened lives waste money, create hazards, and fail to perform their intended horticultural function. The bulletin highlights the importance of selecting a tree right for the location in which it will be planted. Key suggestions for making sound horticultural decisions along with ten examples of trees planted in locations where problems can far outweigh the benefits are presented.

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