Bridge design should take into account not only safety and functionality, but also the cost effectiveness of investments throughout a bridge life-cycle. This work presents a probabilistic approach to compute the life-cycle cost (LCC) of corroding reinforced concrete (RC) bridges in earthquake prone regions. The approach is developed by combining cumulative seismic damage and damage associated to corrosion due to environmental conditions. Cumulative seismic damage is obtained from a low-cycle fatigue analysis. Chloride-induced corrosion of steel reinforcement is computed based on Fick’s second law of diffusion. The proposed methodology accounts for the uncertainties in the ground motion parameters, the distance from source, the seismic demand on the bridge, and the corrosion initiation time. The statistics of the accumulated damage and the cost of repairs throughout the bridge life-cycle are obtained by Monte-Carlo simulation. As an illustration of the proposed approach, the effect of design parameters on the life-cycle cost of an example RC bridge is studied. The results are shown to be valuable in better estimating the condition of existing bridges (i.e., total accumulated damage at any given time) and, therefore, can help schedule inspection and maintenance programs. In addition, by taking into consideration the deterioration process over a bridge life-cycle, it is possible to make an estimate of the optimum design parameters by minimizing, for example, the expected cost throughout the life of the structure.

In this study, a three-dimensional, three-phase dynamic simulation model based on geological investigations of Korolev oilfield in Kazakhstan was used as a development planning tool in order to improve performance of three new wells. The model, developed previously by means of a seismic study, well log and core data, incorporating with characteristics of oilfield productivity, properties of reservoir, liquids and gases that are saturating the hydrocarbon-bearing horizon can be used to calculate development parameters for Korolev field, including production well locations, drilling schedules, and to facilitate both long-term and short-term forecasting for the purposes of optimizing the hydrocarbon recovery from the field. The objective of this work is to assess the impact of adding 3 extra producing wells and find ways to optimize cumulative production with the least impact on the existing development plan by means of deeper understanding subsurface dynamic processes of the Korolev field. The challenge is a high degree of connectivity between wells in the productive formation throughout the field so that any change of production parameters affects the whole field&rsquo / s cumulative production. Trying to find a solution to optimum production of the reservoir forecast studies were carried out, the impact of each new well on development parameters was defined, sub-surface processes changes due to extra producers lead-in were explained and as a result of this thesis two optimization models were proposed, one of which will bring nearly 9.7 million barrels more oil.

Coastal regions are very important because they provide a lot of resources and benefits for all the humankind. Coastal defense structures protect coastal regions from wave attacks. However, the cost of construction such coastal defense structures are very high and need big investments. Hence, to reach the optimum design and minimize the risk of failure has vital importance during the design stage of these structures. Model studies are the most effective tool in optimizing the design of these structures. Rubble mound coastal defense structures were constructed with assembly of different sizes of armor stones and front slopes. Rubble mound coastal defense structures were designed by Van der Meer

From 2008, employee stock bonus must debt expense according to national law and policy. How to get balance between employees and shareholders without eroding benefits becomes the most difficult challenge to many enterprises. The employee stock bonus has been implemented in Taiwan for a long time. This system does play a significant role in high-tech industry and make a great contribution to Taiwan¡¦s economics. However, since a series of business scandals starting with Enron case in 2001, this unique system has been broadly discussed and caused serious debates. One of the most controversial arguments claims that employee stock bonus will weaken the stock price and hurt equity. The study is based on pooled time-series data during 1998-2007 from the IC industry corporations trading on the Taiwan Stock Exchange Corporation and Over-The-Counter market. The purpose is to examine the impact of employee stock bonus on Taiwan stock market by analyzing the variation in Cumulative Average Abnormal Revenue (CAR). The empirical results are summarized as follows: 1.With the factor of employee stock bonus, the ex-dividend effects still existed in IC industry of Taiwan stock market. The negative CAR was particular in evidence on the three days prior to the ex-date. There were no obvious trends of ex-dividend effects during this decade. Both employee stock bonus and dividends were declined year by year which represented that corporation had adjusted their policy with a downward tendency. 2.Before the ex-date, the group of moderate employee stock bonus was beneficial to the CAR and created better performance of stock price with the least dilution effect. On the contrary, the group of low employee stock bonus came out the worst performance. After the ex-date, the group of high employee stock bonus exhibited the best ex-dividend effects and sustained the performance longer. But the group of low employee stock bonus still performed poorly with the most negative CAR. Base on above findings, employee stock bonus not really hurt the stock price but benefit equity if corporations use this system adequately. High employee stock bonuses maybe deliver a positive signal which implicates a bright future.

Local agencies must comply with environmental justice regulation and as such, it is important that they possess practical tools to identify target populations and assess impacts of projects, programs, and policies on these populations. These tools are not readily available or fully developed to evaluate impacts on a regional level, especially when the impacts are benefits rather than burdens. This issue comes into play when accessibility is assessed. This analysis measures accessibility for an environmental justice evaluation using spatial statistical clusters and cumulative opportunity. It shows that the majority of schools, libraries and local transit lines are within areas with high concentrations of target populations, however, park space is limited in these areas. Alternative approaches for environmental justice assessments of regional outcomes such as accessibility provide opportunities for MPOs to gain a greater understanding of the regional impacts of transportation improvements as well as more accurately comply with the spirit of environmental justice regulations.

In recent decades, the environmental issues from the construction sector have attracted increasing attention from both the public and authorities. Notably, the bridge construction is responsible for considerable amount of energy and raw material consumptions. However, the current bridges are still mainly designed from the economic, technical, and safety perspective, while considerations of their environmental performance are rarely integrated into the decision making process. Life Cycle Assessment (LCA) is a comprehensive, standardized and internationally recognized approach for quantifying all emissions, resource consumption and related environmental and health impacts linked to a service, asset or product. LCA has the potential to provide reliable environmental profiles of the bridges, and thus help the decision-makers to select the most environmentally optimal designs. However, due to the complexity of the environmental problems and the diversity of bridge structures, robust environmental evaluation of bridges is far from straightforward. The LCA has rarely been studied on bridges till now. The overall aim of this research is to implement LCA on bridge, thus eventually integrate it into the decision-making process to mitigate the environmental burden at an early stage. Specific objectives are to: i) provide up-to-date knowledge to practitioners; ii) identify associated obstacles and clarify key operational issues; iii) establish a holistic framework and develop computational tool for bridge LCA; and iv) explore the feasibility of combining LCA with life cycle cost (LCC). The developed tool (called GreenBridge) enables the simultaneous comparison and analysis of 10 feasible bridges at any detail level, and the framework has been utilized on real cases in Sweden. The studied bridge types include: railway bridge with ballast or fix-slab track, road bridges of steel box-girder composite bridge, steel I-girder composite bridge, post tensioned concrete box-girder bridge, balanced cantilever concrete box-girder bridge, steel-soil composite bridge and concrete slab-frame bridge. The assessments are detailed from cradle to grave phases, covering thousands of types of substances in the output, diverse mid-point environmental indicators, the Cumulative Energy Demand (CED) and monetary value weighting. Some analyses also investigated the impact from on-site construction scenarios, which have been overlooked in the current state-of-the-art. The study identifies the major structural and life-cycle scenario contributors to the selected impact categories, and reveals the effects of varying the monetary weighting system, the steel recycling rate and the material types. The result shows that the environmental performance can be highly influenced by the choice of bridge design. The optimal solution is found to be governed by several variables. The analyses also imply that the selected indicators, structural components and life-cycle scenarios must be clearly specified to be applicable in a transparent procurement. This work may provide important references for evaluating similar bridge cases, and identification of the main sources of environmental burden. The outcome of this research may serve as recommendation for decision-makers to select the most LCA-feasible proposal and minimize environmental burdens. / <p>QC 20150311</p>

This dissertation presents a clear and systematic method for conducting cumulative effects assessments in the United States in a manner consistent with the 1997 guidelines of the President's Council on Environmental Quality and the 1999 guidance of the U.S. Environmental Protection Agency's Office of Federal Activities. This method has been developed in a collaborative process with federal and State of Alaska regulatory agency scrutiny during the renewal of the federal and state right-of-way leases for the Trans Alaska Pipeline System in 2004 and in the June 2004 Alaska Groundfish Fisheries Final Programmatic Supplemental Environmental Impact Statement prepared for the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Region. The dissertation describes the process through which the cumulative effects assessment method presented here was developed and presents this approach as a predictive tool with the potential to improve the implementation of sustainable development in the United States. In this context, the dissertation presents an overview of sustainability theory, distinguishing and reviewing representative examples from two major sectors of the sustainable development literature, called here the intergenerational equity strand and the human development strand. It identifies weaknesses in three key areas of the intergenerational equity strand -- lack of theorectical cohesion, insufficient tools for implementation, and an imbalance between normative goals and practical feasibility -- and argues that the human development strand, with its empirical emphasis on metrics and institutional frameworks, offers a model that can serve as a basis for unifying the two strands by providing a theoretical core, implementation tools, and practicable goals. Finally, the dissertation argues that sustainable development is implemented most effectively when it is enabled by institutions that facilitate public involvement, particularly participation by the broadest feasible representation of the affected stakeholders, and that such institutional mobilization can provide a stable and enduring basis to foster the intergenerational equity that is the central, distinguishing feature of sustainability. / text

It is of interest that researchers study competing risks in which subjects may fail from any one of K causes. Comparing any two competing risks with covariate effects is very important in medical studies. This thesis develops omnibus tests for comparing cause-specific hazard rates and cumulative incidence functions at specified covariate levels. In the thesis, the omnibus tests are derived under the additive risk model, that is an alternative to the proportional hazard model, with by a weighted difference of estimates of cumulative cause-specific hazard rates. Simultaneous confidence bands for the difference of two conditional cumulative incidence functions are also constructed. A simulation procedure is used to sample from the null distribution of the test process in which the graphical and numerical techniques are used to detect the significant difference in the risks. A melanoma data set is used for the purpose of illustration.

This thesis centers on nonparametric inferences of the cumulative hazard function of a right truncated variable. We present three variance estimators for the Nelson-Aalen estimator of the cumulative hazard function and conduct a simulation study to investigate their performances. A close match between the sampling standard deviation and the estimated standard error is observed when an estimated survival probability is not close to 1. However, the problem of poor tail performance exists due to the limitation of the proposed variance estimators. We further analyze an AIDS blood transfusion sample for which the disease latent time is right truncated. We compute three variance estimators, yielding three sets of confidence intervals. This work provides insights of two-sample tests for right truncated data in the future research.

River restoration is believed to have the greatest chance of success when action is considered in the broader context of the riverscape. However, methods are lacking to fully integrate systemic connectivity into decision-making. Optimisation, a method of prioritisation, is capable of accounting for longitudinal connectivity, spatial interdependence, and cumulative effects of anthropogenic barriers such as dams and culverts. In addition, optimisation can help ensure that limited restoration funds are efficiently allocated. Despite these advantages, it remains under-employed. I present optimisation models for maximising connectivity within a river network (i.e., undirected connectivity) and connectivity between the network and its outflow (i.e., directed connectivity) and demonstrate their application on three river networks in Nova Scotia, Canada. Non-additive cumulative effects of barriers and key budget thresholds that yielded better returns on investment were observed. The methods and models address current challenges in implementation of the optimisation approach to systematic river restoration planning. / Master's Thesis