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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

ANALYSIS OF TWO-YEAR COLLEGES: TRANSFER, RETENTION AND GRADUATION

Patel, Darshak P. 01 January 2011 (has links)
Investment in higher education is typically considered as a static discrete-choice problem where students make post-secondary education choices usually right after high school (Heckman et al., 2006). This is largely aligned with Becker’s human capital theory. As Becker’s theory holds, students’ decisions can alter with the arrival of new information (Weisbrod, 1964). By relaxing the assumption certainty in the human capital model, student education decisions can be modeled using Weisbrod’s option value theory. According to this theory, students reevaluate their lifetime-utility maximizing decisions based on new information acquired in a sequential nature. Students face large uncertainties due to unexpected positive and negative shocks. This dissertation benefits from utilizing student earnings while in school to proxy for these shocks and opportunity costs. Students test both the schooling and labor market to gain new information to maximize their lifetime earnings. Since higher education choices are dynamic in nature, this dissertation benefits from the use of hazard models as these models explicitly account for time. Overall, the dissertation is largely focused on estimating the effect of time-variant and time-invariant variables on the timing of student higher education investment decision. Time to dropping out or transferring is directly correlated with the cost of education. As students take longer time to transfer or shorter time to drop out, acquiring a bachelor’s degree will take longer. These increases in the cost of education eventually decrease the supply of skilled labor and increase the burden on the state and taxpayers. Using a large administrative data from Kentucky Community and Technical College System (KCTCS) matched with administrative earnings data from Kentucky’s unemployment insurance department, results indicate that increases in student earnings increases time to transfer, decrease time to stopout early and decrease time to graduate. The opportunity cost of continuous enrollment is high and students weigh current events more than future events. Similarly, as students age, the number of years left to enjoy full benefits from another semester of education decreases and hence students are more likely to stopout earlier or transfer later as they age. Lastly, variables that were proxy for ability promote attendance, transfer and graduation.
252

Engineering Geomorphological Assessment and Slope Hazard Identification of the Haast Pass Highway Corridor, State Highway Six, Haast Pass New Zealand

Walsh, Andrew Timothy January 2015 (has links)
The Haast Pass highway has had a long history of instability since it was constructed in 1960. Steep slopes and deeply incised river create an actively changing geomorphic environment making maintaining the highway corridor hazardous and difficult. This thesis study provides the first comprehensive investigation of the highway corridor between the Summit and Thunder Creek Falls using LiDAR and detailed air-photo analysis to provide the basis for geomorphic mapping. Management of slope hazards to date has been based on a reactive approach treating the immediate unstable areas around landslides after they occur. This study presents the first large-scale geomorphological assessment of the highway corridor identifying surface unit type, slope processes and slope hazards in order to facilitate the development of a long-term highway management strategy. Because dense vegetation covers nearly all the slopes above the highway in the study area as as such, it has not been possible to adequately investigate slope geomorphology until the availability of LiDAR. This study is the first to use Light direction and ranging[LiDAR] for corridor hazard mapping beneath dense vegetation in New Zealand. The LiDAR survey was flown by New Zealand Aerial Mapping in January 2014 for the New Zealand Transport Agency and was provided for use in this study. The LiDAR surface model created serves as the basis for mapping surface units and landslide features, enabling the identification of slope processes and landslide hazards. Aerial photos were also used to identify surface unit type and slope processes where vegetation was absent and enabled the activity of slopes to be evaluated. Interpretations made using LiDAR were validated using aerial photography and targeted ground truthing with all ground truthing sites confirming the interpretations made. Large scale geomorphology mapping was undertaken on slopes above the highway on the western side of the valley and showed that there were distinct differences between the southern and northern parts of the highway corridor. Between The Haast Pass Summit and Pipson Creek the slopes are dominated by schist bedrock with regolith confined to small deposits next to the highway and larger deposits in tributary valleys. The slope hazards affecting the highway in this zone are confined to debris sliding and rockfall from regolith deposits and bedrock cliffs next to the highway between Robinson and Pipson Creeks. The slopes between Pipson Creek and the Gates of Haast, in contrast, consist of deep regolith deposits and regolith veneered slopes. Evidence of active and recently active slope processes on the slopes facing the highway confirm the instability is associated with slope hazards including debris flows, debris slides, rock fall and highway collapse. Small-scale detailed evaluations were undertaken at Diana Falls, Ford Creek, The Hinge and the Gates of Haast with the sites selected based on their history of instability and/or their particu- larly hazardous appearance during the large-scale geomorphology and hazard identification. Using the LiDAR surface model surface units and landslide features were identified and mapped with small-scale engineering geomorphology maps. This information was then used to interpret the subsurface geometry and the failure mode/slope processes acting on the slope enabling an assessment of the current stability and future slope development to be made. Diana Falls was found to have scarps and tension cracks running across the regolith covered slope indicating that future landslides from this site will be an ongoing problem. At Ford Creek the landslide was identified as a rock compound slide, but assessments of its current stability and future development were unable to be made. Detailed investigations at The Hinge revealed evidence of a large creeping debris slide and the existence smaller debris slides below the highway through the entire investigation area; the debris slides identified show signs of activity and continued debris sliding will continue to affect the highway in the future. The investigation of the Gates of Haast revealed that the slope instability is not as extensive as it has been in the past, however, recent rock slides and debris flows have continued affect the highway and will continue to pose a hazard in the future. This thesis provides fundamental information required to develop a comprehensive management plan for the Haast Pass highway corridor between the Haast Pass summit and the Gates of Haast. A new landslide management plan has been developed outlining immediate, short-term and long- term options and programmes that should be implemented. Immediate options are steps that can be taken to quickly increase the safety of road users and include moving of highway closure gates and installation of warning signage. Short-term options aim to mitigate landslide hazards where feasible including the installation of rockfall barriers and debris flow attenuators, and lay the groundwork for future avoidance of hazards by undertaking investigations of highway realignment and developing highway closure rainfall thresholds. Long-term options are recommended where landslides will continue to impact the same section of the highway repeatedly and focus on hazard avoidance by building landslide shelters or major highway realignments. The adoption of a management plan ensures security of the highway, protects against loss of life and provides the most cost effective long-term solution to manage the landsliding hazards.
253

What's in a map? communicating natural hazard forecasts.

Baird, Nathanael Lloyd January 2014 (has links)
The number of people suffering from natural disasters, and the economic impact of those disasters, continue to increase as the years go by. Better preparation and risk management strategies can help lessen the impacts of these disasters. One important aspect of risk management is risk assessment, which can be accomplished with a hazard map. One application of hazard maps is to forecast volcanic ashfall following an eruption to help people and organisations prepare themselves for, and mitigate the detrimental impacts of, volcanic ashfall. This research evaluated the key elements of a hazard map and how to make a hazard map most effective through the study of short-term ashfall forecast maps in New Zealand. A mixed-methods approach was taken for this research. Interviews were conducted with scientists at GNS and stakeholders who use the ashfall forecast maps. After the data from the interviews was analysed, an internet-based survey was created and sent out to anyone interested in participating. The survey served as a low-resolution verification of the high-resolution data gathered in the interviews. After each stage of information gathering, the ashfall forecast map design was updated. This research found that there are seven basic elements which should be considered when creating a hazard map. These elements are: simplicity of the map, base map, map scale, the use of colour, geographical information, the inclusion of uncertainty, and time. This research also found key lessons which can be applied to any hazard map creation process. These lessons are: established practices should be revaluated periodically, communication between the information provider and the enduser is critical, the information provider must decide between satisfying the individual or the group, education and outreach are important, audience feedback is necessary for an effective map, and that hazard maps are just one step in the risk mitigation process.
254

An Experimental Investigation of Ignition Propensity of Hot Work Processes in the Nuclear Industry

Mikkelsen, Kai January 2014 (has links)
The National Fire Code of Canada (NFCC) is one model code which regulates hot work in Canada. The code specifies that hot work processes need only create heat to be considered hot work processes, and requires that precautions taken adhere to those in Canadian Standards Association (CSA) W117.2, which is intended for welding, cutting and allied processes. CSA W117.2 requires a 15 m spherical radius of separation in which combustibles are ideally relocated or, at minimum, be protected with fire blankets. Openings, cracks and other locations in which sparks or hot particles must also be protected within this distance. Additionally CSA W117.2 requires a fire watch during, and one hour following the completion of the work. The NFCC stipulates more stringent requirements on the fire watch than CSA W117.2, requiring a check back 4 hours after the work. The code in its current form requires the same precautions be taken when using a soldering iron or epoxy resin as when using an oxyacetylene torch to flame cut steel. The lack of hazard characterization of hot work processes, and the umbrella prescription of required fire safety precautions can result in insufficient measures to prevent fires in some scenarios, and inordinate precautionary measures in others. While not applicable law in all jurisdictions, the NFCC is relied on in various Canadian industries for regulative purposes. Nuclear power generation in Canada is one such industry facing onerous fire protection costs resulting from following these precautions for the smallest of jobs requiring heat producing tools. The literature review highlights the dearth of scientific knowledge regarding the propensity of hot work as an ignition source and how this shortcoming manifests itself in issues across the various standards governing hot work practices. The objective of this research is to assess fire hazards resulting from various processes considered hot work under the National Fire Code of Canada (NFCC). Due to the breadth of processes covered by the NFCC, a spectrum of hot work activities was investigated from processes as innocuous as the application of heated adhesive, to well known sources of ignition such as a variety of welding processes, oxyacetylene cutting and plasma cutting. To streamline the hazard assessment, processes were categorised into three groups based upon expected hazards such that testing could focus on the most prominent ignition danger presented by each. The groups were those processes exhibiting hot surface ignition hazards, processes with hot surface ignition hazards in addition to limited potential to generate hot particles, and those processes in which the generation of significant quantities of spark and hot particles is guaranteed. For the first two process categories, experimentation focused on determining a critical process temperature with which to rank processes and also compare with ignition temperatures of combustibles commonly involved in hot work fires. The critical process temperature was determined as the highest measured temperature of the workpiece or tool during the chosen process and was typically measured with the use of thermocouples and infrared thermography. Characterization of any hot particles in the second category was performed using infrared thermography, and in some cases, thermal paper. Literature sources indicated that sparks and hot particles are the largest factor in hot work fires, so specialised methodology was developed for the third category of processes to characterise the distribution of many thousands of hot work particles generated during welding, thermal cutting and other hot particle producing work. The distributions collected were used to determine the area enveloped by the ignition hazard of hot particles as well as areas encompassing the highest threat to combustibles in relative terms. Several of the processes as studied were found not to exhibit any measurable form of ignition hazard, including forms of manual sanding and filing and rotary filing of steel. Heated adhesive, cutting steel with a reciprocating saw and drilling of steel were shown to exhibit moderate degrees of hazard with temperature rise of 195\degree C or less, suggesting potential hazard to a limited group of combustibles. Welding and cutting processes were shown to have a relative ignition potential across a wide area. Typical welding procedures produced hot particles which travelled a maximum of approximately 3 - 4 m while thermal cutting processes ejected sparks, slag and hot particles up to 9.8 m from the work. Incorporated properly into updated standards and codes, the results and findings of this research could drastically improve the Canadian model codes regarding the regulation of hot work by decreasing cost and difficulty for Canadian Industry without increasing the risk of loss.
255

The mathematics of principal-agent problems

Liu, Bibo 08 April 2010 (has links)
The principal-agent problem is an important model in the field of Economics of Information. In this thesis we study only a particular type of principal-agent problem which is called moral hazard model and by the principal-agent problem we mean it is moral hazard model. The moral hazard model actually belongs to the class of bilevel programming problems in Mathematics. In Economics. the first order approach is used to reduce the principal-agent problem to a single level optimization problem. However, this approach is only valid under some strong conditions. Moreover the approach can only be used under the assumption that the optimal action of the principal-agent problem and its relaxed problem appears only at an interior point. In this thesis, we consider a new relaxed problem. Under more general assumptions. we can solve the principal-agent problem without restricting the optimal action of the agent to be in the interior.
256

Prospective Hazard Analysis of Patient Identification Processes in the Neonatal Intensive Care Unit

Rooney, Shannon L. 15 February 2010 (has links)
Neonatal Intensive Care Unit (NICU) patients present unique patient identification challenges. Prospective hazard analysis (PHA) assesses safety by identifying hazards before an adverse event occurs. This project analyzes a barcoded feeding process in one NICU, and conducts a preliminary evaluation of PHA methods. Observations were conducted to quantify patient identification methods used in one NICU; the unit’s barcoded feeding process was examined for potential failures. The process underwent PHA with two methods, Global Hazard Ratings (GHR), a simplified method developed for this project, and Failure Modes and Effects Analysis (FMEA). FMEA showed greater interrater reliability; there was poor agreement between methods. A list of 21 hazards was developed for the clinical team from the FMEA results. Recommendations are for the unit to formulate and implement mitigation strategies for the identified hazards. Future work involves a more in depth look at FMEA interrater reliability and reliability comparison with other PHA methods.
257

A System Approach To Occupational Health And Safety Management

Gozuyilmaz, Cem 01 December 2003 (has links) (PDF)
In this thesis, methods used at present in occupational health and safety management are analyzed and a model safety management system is developed. History, development and recent occupational safety regulations in the United States of America and European Union are introduced to give a sight on this subject in developed countries. The suggested model is evaluated with work accident data taken from a company and hazard and risk analysis methods are used to investigate these accidents. Preventive measures to eliminate and reduce the consequences of these accidents are recommended. Finally a model safety management system which can be used in all types of industry is developed.
258

Risk analysis of coastal flooding due to distant tsunamis

Gica, Edison January 2005 (has links)
Mode of access: World Wide Web. / Thesis (Ph. D.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 410-414). / Electronic reproduction. / Also available by subscription via World Wide Web / xxxi, 414 leaves, bound ill. (some col.), col. maps 29 cm
259

Integrated field investigation, numerical analysis and hazard assessment of the Portillo Rock Avalanche site, Central Andes, Chile

Welkner, Daniela 05 1900 (has links)
This thesis reports a rock slope hazard investigation located in the Central Andes of Chile, where two significant rock mass wasting events were recognized. Dating using cosmogenic nuclide for ³⁶Cl showed that the deposits were post-glacial in age, corresponding to the Upper Pleistocene Portillo Rock Avalanche (PRA) and a Holocene rock slump and rockslide. The pre-historic landslide deposits underlie both a key transportation route between Chile and Argentina and an important ski resort. The purpose of this research was to investigate the likely failure mechanism and characterise the runout path and volume of the PRA. The insights gained on the back analysis of the slope were used in later stages to assess the hazard potential of a recurring major rockslide. The distinct element code UDEC was used to evaluate the failure mechanism. Elasto-plastic modelling results showed that sliding and shearing along the bedding planes together with brittle fracturing and shearing through the toe of the slope likely had occurred. Runout simulations were carried out using DAN3D. Combinations of rheologies were tested and ranked based on their ability to represent the current distribution of the debris by means of pre-failure topography reconstruction and volume estimates of the deposits. Results showed that the best basal rheological combination for the PRA was frictional during the rockslide and Voellmy when entrainment became important. In contrast, a constant frictional basal rheology best represented the Holocene rock slump. The performance of the present-day state of the slope was tested under different scenarios. Under static condition the slope proved to be stable indicating a stabilized geometrical profile with time. Also, the slope proved to be stable under increased pore water pressures at its toe. Finally the modelled slope was subjected to a seismic load (M=7.8) and its crest failed due to an outward rotation of blocks, probably aided by topographic amplification. The runout simulations showed that the leading edge of the flow could override part of the International Santiago-Mendoza Corridor with no direct impact to the Portillo Ski Resort. Overall, though, under this highly unlikely dynamic condition for the site, the hazard level is very low.
260

Urban floodplain land-use - acceptable risk? : A case study of flood risk perception on the Guragunbah (Carrara-Merrimac) floodplain, Gold Coast

Godber, Allison Maree January 2005 (has links)
In Australia, the developments of hazard-specific legislation, policy and guidelines aims to minimise community exposure to the adverse effects of natural hazards. This occurs under policies of ecologically sustainable development land-use planning processes, which must also now involve the assessment of hazard-risk. However the development occurring in potentially hazardous environments, for example urban floodplains susceptible to flooding, continues to occur as a result of contemporary land-use planning and risk management processes. Why is this an outcome of past and present risk management and land-use planning processes? This thesis finds that a significant factor contributing to this outcome is the discrepancy between the perception and management of risk, particularly acceptable risk, by stakeholders (Local Government, the development industry, risk managers and floodplain occupants). The research is based on an Australian example of an urban floodplain currently under considerable development pressure, but at risk from flooding – Guragunbah (Carrara Merrimac Floodplain) and surrounding suburbs within the Nerang River catchment on the Gold Coast. A case study methodology was adopted, involving a combination of survey data and secondary documents. A basis for the thesis was the modelling of the actual risk decision-making processes operating within the case study Local Government, and the comparison between actual observed process and the theoretical framework outlined by the existing hazard risk management and land-use planning policy, guidelines and legislation. This enabled the identification of key stakeholders and their roles within the risk management and land-use planning processes operating within the case study area. The scope of the results of this thesis indicate that a large proportion of stakeholders external to the Local Government (such as residents and some members of the development industry) do not understand the risks of flooding represented by the standards formally adopted by local government (1-in-100 year flood, for example) and as a result, misinterpret their levels of flood risk exposure. Importantly, the results also indicate that contrasts exist in the flood risks considered to be ‘acceptable’ by the stakeholders, particularly when the potential consequences associated with events are described or illustrated in ‘non-technical’ terms. The extent to which the formal standards are misinterpreted suggests that many stakeholders may potentially be exposed to risks greater than they consider to be ‘acceptable’, but they are assuming that the Local Government (in particular) is setting risk standards that are acceptable to them. The thesis questions the true ‘acceptability’ of the formal standards being adopted through floodplain management policy at the Local, State and Federal levels of Government and identifies management opportunities and constraints in addressing the issue. Obstacles to management change include resource availability, lack of political will and stakeholder consultation. Opportunities for management change include modifying: the approach adopted by Local Governments when constructing planning schemes; the existing planning standards and decisions associated with permissible individual land-use; the mitigation of existing flood risks and exposure; and the communication of flood risk information. In the ‘real-world’ Local Government context, as illustrated by this case study, the issue may be practically addressed by modifying the standards and processes followed to establish acceptable risk.

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