Storage of carbon dioxide is being actively considered for the reduction of green house gases. To make an impact on the environment CO2 should be put away on the scale of gigatonnes per annum. The storage capacity of deep saline aquifers is estimated to be as high as 1,000 gigatonnes of CO2.(IPCC). Published reports on the potential for sequestration fail to address the necessity of storing CO2 in a closed system. This work addresses issues related to sequestration of CO2 in closed aquifers and the risk associated with aquifer pressurization. Through analytical modeling we show that the required volume for storage and the number of injection wells required are more than what has been envisioned, which renders geologic sequestration of CO2 a profoundly nonfeasible option for the management of CO2 emissions unless brine is produced to create voidage and pressure relief. The results from our analytical model match well with a numerical reservoir simulator including the multiphase physics of CO2 sequestration. Rising aquifer pressurization threatens the seal integrity and poses a risk of CO2 leakage. Hence, monitoring the long-term integrity of CO2 storage reservoirs will be a critical aspect for making geologic sequestration a safe, effective and acceptable method for greenhouse gas control. Verification of long-term CO2 residence in receptor formations and quantification of possible CO2 leaks are required for developing a risk assessment framework. Important aspects of pressure falloff tests for CO2 storage reservoirs are discussed with a focus on reservoir pressure monitoring and leakage detection. The importance of taking regular pressure falloffs for a commercial sequestration project and how this can help in diagnosing an aquifer leak will be discussed. The primary driver for leakage in bulk phase injection is the buoyancy of CO2 under typical deep reservoir conditions. Free-phase CO2 below the top seal is prone to leak if a breach happens in the top seal. Consequently, another objective of this research is to propose a way to engineer the CO2 injection system in order to accelerate CO2 dissolution and trapping. The engineered system eliminates the buoyancy-driven accumulation of free gas and avoids aquifer pressurization by producing brine out of the system. Simulations for 30 years of CO2 injection followed by 1,000 years of natural gradient show how CO2 can be securely and safely stored in a relatively smaller closed aquifer volume and with a greater storage potential. The engineered system increases CO2 dissolution and capillary trapping over what occurs under the bulk phase injection of CO2. This thesis revolves around identification, monitoring and mitigation of the risks associated with geological CO2 sequestration.

The goal of this work was to evaluate matrix acidizing treatments of vertical and horizontal wells in carbonate reservoirs. Twenty field cases for acidizing treatments were analyzed by evaluating the skin factor evolution from on-site rate/pressure data during the treatment. A skin monitoring method based on the concept of inverse injectivity (Hill and Zhu, 1996) was used to calculate the skin factor evolution. Viscous diversion techniques were analyzed by using the viscous diversion skin model that accounts for viscosity contrast between the reservoir fluid and the injected fluid. The estimated skin evolution during the treatment was validated using the post-treatment well performance. From the post-treatment analysis, it was observed that emulsified acid was not an efficient viscous diverter because only 27% of the wells treated with emulsified acid showed evidence of viscous diversion. Therefore, other viscous diversion techniques are needed to ensure uniform acid coverage. In addition, treatments that involved diversion techniques such as foam, associative-polymers, and viscoelastic surfactants were also evaluated. Thus, the post-treatment evaluation was used to improve and optimize the acid treatment designs. This study was beneficial to diagnose if excess acid volumes were used, or effective diversion was achieved during the acid treatment.

This thesis studies and develops an agent-based on-line monitoring and diagnosis system. With the advent of industry facilities toward high speed and automation, the on-line monitoring and diagnosis mechanism becomes important. The traditional time-based maintenance strategy cannot consider all practical conditions of machines. The accidental breakdowns may occur unexpectedly. In order to make production line automation, yield high production rate, and enhance the ability of market competition, an effective way is to ensure facilities running smoothly and to reduce the manpower monitoring. Meanwhile in order to reduce the cost of development and enhance the feature of reuse, we use a communication interface to integrate and interact information among developed softwares. Through this system, users may easily monitor and diagnose the machines on production lines through user interfaces, such as display of machine status, malfunction alarming, trend chart, waveform, spectrum, cepstrum and envelop spectrum, etc. A model consisting of domain knowledge and behaviors of cooperative multi-agents to integrate various facilities and functions in different production lines is proposed. In addition, via a Web-based environment, it releases the restrictions by of temporal and regional isolation. The system provides a real-time and dynamical operation circumstance and can meet the needs of different levels of users. Consequently, it is of greatly help to lower the cost of personnel and enhance the ability of market competition.

In the past years, due to the rapid growth of high-tech industries, the power supply requirements are becoming much stricter. Many of sensitive equipments are often affected by various power quality (PQ) problems to malfunction, as a result, the customer complaints. Before the mitigations of PQ are decided, the PQ monitoring system should be setup to find out the causes of PQ problems. The aim of this thesis is to establish a PQ monitoring system to investigate the quality of power in Kaohsiung Area for different types of customers. The recorded data not only are used to calculate different PQ of various parameters indices such as harmonics, voltage unbalance, voltage flicker, and voltage events, but also to confer the levels of typical devices affected by voltage sag events. The related measuring techniques include selection of monitoring sites, threshold settings of recorder, the ability to capture events, and the data collection and analysis are included in this thesis. Analysis results are compared to PQ standards to understand the actual quality of power delivery in the Kaohsiung Area.

I examine two sets of incentives faced by corporate CEOs to determine how they respond to those incentives. I compare firms that restate financial statements to firms that do not restate to test the hypotheses that bank monitoring should provide incentives to deter misreporting. For relatively less (more) severe misreporting, I find the likelihood of misreporting is positively related (unrelated) to bank borrowing, and that ex ante changes in bank debt are positive (unrelated) for misreporting firms versus control firms. These results suggest that bank monitoring is insufficient to deter or detect misreporting, rather that it may provide incentives for managers to engage in relatively less severe misreporting, consistent with the "debt covenant hypothesis". I next examine the incentives that CEOs have to increase firm value that result from their compensation packages and opportunities for advancement in the managerial labor market. Traditional methods for estimating pay-performance sensitivity exclude incentives that derive from opportunities for advancement in the managerial labor market and assume a linear relation between changes in pay and changes in performance. But results in recent literature imply that advancement opportunities may be a significant source of incentives and that the relation between changes in pay and changes in performance may depend upon the level of performance. I estimate payperformance sensitivities that incorporate these results. I find that although performance may be positively related to opportunities for advancement, the contribution to a CEO's total pay-performance sensitivity is too small to be economically significant. I also find that pay-performance sensitivities vary depending on the level of performance and may be higher or lower than estimates from linear models suggest. In sum, observed CEO pay packages may not be as suboptimal as some prior studies suggest.

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

A physically-based, distributed sediment yield component has been developed for the SHE hydrological modelling system. This new component models the hillslope processes of soil detachment by raindrop impact, leaf drip impact and overland flow, and transport by overland flow. If the eroded soil reaches a river system it is routed downstream along with any inobilised river bed material. Deposition on land or in a river is simulated and the river bed material size distribution is continuously updated with allowance for armour layer development. The equation developed for soil detachment by raindrop and leaf drip impact was successfully tested using data from a field plot with a range of soybean canopy covers and rainfall intensities. The soil detachment coefficient in this equation was determined for a range of soil types and showed a variation consistent with that which may be expected from a consideration of the physics of a soils resistance to detachment. At present two soil detachment coefficients need calibration. In order to investigate the variation in these coefficient values, as well as to test the component, various applications were carried out. The hilislope sub-component was applied to rainfall simulator plots with a variety of surface conditions. Two sets of calibration parameters, distinguishable on a physical basis according to the degree of soil disturbance, were found to be appropriate for all the plots. To investigate scale effects, parameters calibrated at the rainfall simulator plot scale were transferred to a 1-ha rangeland sub-catchment. With no further calibration, the catchmerit response for four events was poorly simulated for both water and sediment. However, with reasonable variations in the antecedent soil moisture content but no variation in plot calibrated sediment parameters, the sediment yield for two of the four events could be successfully simulated. These applications suggest that parameter transfer is feasible if the sediment yield characteristics at the different scales are similar. Further applications of the hilislope sub-component were carried out for two small agricultural catchments. The sediment response could be simulated to at least the same accuracy as achieved by two existing distributed soil erosion models. The channel sub-component was applied to the East Fork River, Wyoming. Although the complex sediment storage/supply effects could not be reproduced completely, the simulated response was nevertheless of similar accuracy to that achieved by two existing alluvial river models. The new component is considered to be a valuable contribution to sediment yield modelling as a physically-based approach is used for both the hilislope and channel phases of the catchinent sediment system, within the framework of an advanced hydrological modelling system.

Introduction: Pedometers are increasingly used as a self-monitoring aid for achieving and increasing daily physical activity. Older pedometers had varied levels of accuracy ranging from 0 to 45% difference and were needed to be positioned in a certain way (on the waist). Newer models can be placed anywhere on the body but its accuracy is unknown when they are placed at different bodily sites. Purpose: We determined the accuracy of various newer pedometers under controlled laboratory and free walking conditions. Method: A total of 40 subjects (20 male and 20 female) varying widely in age (18-61 years) and BMI (18-38 kg/m²) were studied. The pedometers, including Omron HJ-320, Omron HJ-324U, Lifesource XI-25, Fitbit Ultra, and Virgin Health Miles, were placed at waist, at chest, in a pocket, and on an armband. The number of steps recorded with the pedometers was compared against those counted with a hand tally counter while the subjects walked on the treadmill at 54, 80, 107, 134, and 161 m/min and on paved ground outside at a self-selected pace. Results: With the exception of one, all the pedometers were accurate (within ±5% of the criterion measure) at moderate walking speeds (80 and 107 m/min). The results were similar no matter where the pedometers were placed on the body and where the walking was performed. There were general tendencies for the accuracy to decrease at slower and faster walking speeds in most pedometers. The mean difference scores increased particularly when the pedometers were placed in the pockets or in the purse. Conclusions: Most of the pedometers examined were accurate when they were placed at waist, chest, and armband no matter what walking speed or what terrain they exercised. But some pedometers did not register accuracy when they were put in the pocket or in the purse particularly at a slow and fast walking speed. / text

Abstract Air monitoring was conducted in a nickel base metal refinery to determine compliance with occupational exposure limits. The hypothesis stated that levels of airborne dust may pose a risk to worker health if compared to the relevant exposure limits. Exposure limits for nickel species are set for the inhalable nickel dust fraction. Personal air samples, representative of three selected areas were collected in the workers’ breathing zones, using the Institute of Occupational Medicine (IOM) samplers. Real-time personal samples were collected randomly over a two-month period in three nickel production areas. Filter papers were treated gravimetrically and were analysed for soluble and insoluble nickel through inductive coupled plasma-mass spectrometry (ICP-MS). Measured concentrations were expressed as time weighted average exposure concentrations. Results were compared to South African occupational exposure limits (OELs) and to the threshold limit values (TLVs) set by the American Conference of Governmental Industrial Hygienists (ACGIH) to determine compliance. Statistical compliance was also determined using the National Institute for Occupational Safety and Health procedure as prescribed by South Africa’s Hazardous Chemical Substances Regulations in 1995. In two of the areas it was found that exposure concentrations complied with the OELs. Some exposures exceeded the OEL values and most exposures exceeded the TLV values in the other area concerned. A comprehensive health risk assessment needs to be conducted to determine the cause of non-compliance.

Over the last decade, the internet industry has rapidly grown with regard to infrastructure and bandwidth. Widespread internet networks with large bandwidth connect people-to-people, people-to-machines, and machine-to-machine. Like other multimedia services, large bandwidth enables voice services to be provided over IP networks where network connectivity is not consistent. In this context, research on service quality monitoring is necessary to satisfy customers by providing consistent service quality. The major contribution of this dissertation is the development of three novel techniques to improve or measure voice quality over IP networks. This dissertation first addresses an adaptive playout buffer scheduling algorithm that enables systems to lossen delay jitter due to the legacy of packet-switched networks. The scheduling algorithm is operated by a desired quality of service, minimizing the end-to-end delay by adjusting playout delay times. Secondly, this dissertation also explores a parameter-based nonintrusive speech quality measure to monitor the quality of VoIP. During the lifetime of sound, the network parameters are estimated and used to predict the quality of speech. As a cognitive model, a machine-learning technique is exploited to map features in the feature space into the perceived speech quality scale space. Finally, this dissertation introduces a signal-based nonintrusive speech quality measure. Features for the proposed measurement are extracted from observations of the characteristics of natural speech sounds and artificial noises. The calculated features are mapped into the perceived speech quality scale. The proposed parameter-based measure achieves a high prediction accuracy while the signal-based measure reaches to a comparable performance to the official International Telecommunication Union (ITU) standard, P.563. The contributions described in this dissertation provides smart methodologies for monitoring or enhancement of VoIP service qualities. / text