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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.
351

Probabilistic microbial risk assessment and management implications for urban water supply systems

Signor, Ryan S., Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2007 (has links)
Urban drinking-water supplies are still implicated as pathways for the transmission of waterborne disease. A move toward risk informed, proactive water system management has occurred over the past decade and is advocated in current international drinking water guidelines. Quantitative Microbial Risk Assessment (QMRA) is a tool with potential for aiding health risk management; however the refinement of scientific based practical methods to support that philosophy still requires development. This thesis focused on the water utility, its responsibility to manage microbial water safety, and how probabilistic QMRA may aid in developing management strategies. A framework for waterborne disease risk assessment from urban supply systems was derived and tested on an Australian case study. The main premise was that, in order for risk assessment outcomes to inform the management process, the steps should incorporate the concepts of risk variability, the explicit event conditions that can drive it, and that examination of QMRA sensitivity to various risk scenarios/model uncertainties is undertaken. The identified management uses were: (i) prioritising for attention issues hampering the system's ability to meet or the assessor's ability to interpret against (e.g. knowledge gaps about the system), a water quality health target; and (ii) identifying potential strategies or control points for addressing those issues. Additionally, rarely occurring, high impact, adverse fluctuations in treated water quality (and consumer infection risks), especially from source water contaminant "peaks", are highly, nearly totally, influential over the extent of risks averaged over longer, say annual, periods. As such, a case is made calling for widespread adoption of health targets that refer to tolerable consumer risks per exposure, rather than or as well as the current common practice of expressing targets in terms of risks from exposure over a year or lifetime. Doing so may provide incentive and opportunities for improved management, and the future derivation of specific microbial treatment or treated water quality targets, with a view toward protecting the community from extreme high risk periods associated with disease outbreaks.
352

Investigating green building assessment tools: a risk-analysis based approach

Chandra, Shailja, Built Environment, Faculty of Built Environment, UNSW January 2006 (has links)
This research investigates risks arising from the mechanism of green building assessment tools that may impact on the consistency of their outcomes and render them ineffective in reliably fulfilling their goals in the building industry. None of the past efforts at developing assessment tools have focused on the risk aspects of assessment tools. Moreover, slowly the building industry has started placing considerable reliance on them without completely understanding the consequences of potential risks. The origin of risks lies in the realization that assessing sustainability in buildings is complex and full of conflicting concepts and opinions, and that amidst all this, assessment tools are expected to deliver multiple performance objectives and goals. Given that the importance of assessing sustainability in buildings cannot be ignored, it becomes extremely important that assessment tools are understood well and are free from risks. To accomplish this, an array of potential risks are systematically brought together using a risk categorization method, which facilitated a basis to critically analyse the literature in the light of risks. This addressed the acknowledged gap in the literature on risks relating to assessment tools. Four categories are discussed under this categorization. These categories provide a basis for the quantitative investigation, which applies techniques of uncertainty analysis to quantify these risks. In the quantitative investigation, uncertainty in 40 input parameters is propagated through several alternative forms of the mechanism of assessment tools. The input parameters are selected using the assessment data of a case study (Arts Faculty building, University of Sunshine Coast). The design of alternative forms of the mechanism is based on the identified risk categories and is carried out using a vehicle assessment tool (Green Building Tool). The uncertainty propagation is carried out using a risk analysis tool (@Risk). Descriptive statistics is deployed to analyse the results of the uncertainty propagations. Analysis of the results has brought an understanding and insights into various aspects of the mechanism in the context of their predisposition to increase or decrease risks. To ensure that an assessment tool's specific goals are fulfilled, the mechanism needs to be designed carefully so that it is low-risk and appropriate to the intent. By providing in-depth insights into the mechanism, the methodology and outcomes of this research are important for the future development of green building assessment tools.
353

Hypervelocity Impact Induced Disturbances on Composite Sandwich Panel Spacecraft Structures

Ryan, Shannon, shannon.ryan@studentems.rmit.edu.au January 2007 (has links)
The next generation of European scientific satellites will carry extremely sensitive measurement devices that require platform stability orders of magnitude higher than current missions. It is considered that the meteoroid and space debris (M/SD) environment poses a risk to the success of these missions as disturbances induced by the impact of these particles at hypervelocity may degrade the platform stability below operational requirements. In this thesis, disturbances induced by the impact of M/SD particles at hypervelocity on a representative scientific satellite platform have been investigated. An extensive experimental impact test program has been performed, from which an empirical ballistic limit equation (BLE) which defines the conditions of structural perforation for composite sandwich panel structures with CFRP facesheets and aluminium honeycomb cores (CFRP/Al HC SP) has been defined. The BLE is used to predict impact conditions capable of inducing the different excitation modes relevant for a SP sandwich panel structure, enabling a significant reduction in the time and expense usually required for calibrating the protective capability of a new structural configuration. As experimental acceleration facilities are unable to cover the complete range of possible in-orbit impact conditions relevant for M/SD impact risk assessment, a Hydrocode model of the representative CFRP/Al HC SP has been constructed. A series of impact simulations have been performed during which the local impact-induced disturbance has been measured. The numerical disturbance signals have been validated via comparison with experimental disturbance measurements, and subsequently subject to a characterisation campaign to define the local elastic excitation of the SP structure equivalent to that induced by impact of a M/SD particle at hypervelocity. The disturbance characterisation is made such that it is applicable as an excitation force on a global satellite Finite Element (FE) model, allowing propagation of impact-induced disturbances throughout the complete satellite body to regions of critical stability (i.e. measurement devices). The disturbance induced upon measurement devices by M/SD impacts at both near- and far-body locations can then be made, allowing the threat to mission objectives to be assessed.
354

How is risk assessment performed in international technology projects

Cardenas Davalos, Alfonso Daniel, Chia Chin Hui, Wendy January 2010 (has links)
<p>In today’s ever changing business landscape, technology and innovation projects play a key role in creating competitive advantages for an organisation. However, many such projects are often hampered by under performance, cost overruns and lower than predicted revenue (Morris and Hough, 1987 and Christoffersen et al, 1992). This seems to indicate the lack of risk management in the way we manage projects. On the other hand, it is impossible to have any projects without risks. Thus, it is essential to have effective risk management rather than trying to eliminate risk out of projects. These factors have guided this study to focus on understanding the way risk assessment is performed in international technology projects. It aims to identify the link between risk assessment and project categorization, drawing from the ransaction cost economics (TCE) perspective. A qualitative approach applying semi-structured interviews was conducted with ten interviewees holding different roles in the engineering and technology projects within a multinational company with presence in more than 100 countries around the world. The application of the data display and analysis technique by Miles and Huberman (1984, 1994) enables initial findings to be presented using the “dendogram” method, thereafter, leading to the development of a two-dimensional risk assessment matrix as the final result of this study. </p>
355

Relationships between postural control system impairments and disabilities

Allison, Leslie K. 20 October 1997 (has links)
Graduation date: 1998
356

Task and support surface constraints on the coordination and control of posture in older adults

Clark, Sean 20 January 1998 (has links)
Although research evidence clearly indicates support surface properties are a major factor contributing to fall risk among the elderly, investigations examining the influence of variations in surface conditions on the postural control of older adults during task performance have been limited. Thus, the primary purpose of the present studies was to determine whether the coordination and control of body kinematics exhibited by older adults during upright leaning (i.e., leaning forward through the region of stability) and gait would be different across variations in support surface properties. Secondary objectives of these studies included, examining if coordination and control measures of body kinematics differed as a function of the participants' level of postural stability and/or repeated exposure to the support surface properties. Three support surface conditions were selected for inclusion based on resistance properties to applied forces (i.e., normal and shear): rigid, high friction; compliant; and rigid, low friction. For both tasks performed, body kinematics for trials 1-3 (T1) and 10-12 (T2) from 12 completed trials on each support surface were analyzed using three-dimensional (3-D) video analyses. Results of separate univariate repeated measures analyses of variance yielded significant surface condition main effects for lower extremity coordination patterns and postural control strategies in the gait and leaning task, respectively. Additionally, a significant surface condition main effect and an interaction effect of surface condition by trial block were identified for the measure of head stability in the gait and leaning tasks, respectively. Differences in head stability and the control of lower extremity joint motions as a function of level of postural stability (i.e., group differences) were observed only during the walking task. Present findings indicate that during goal-directed behavior, the coordinated movements of the body and its segments emerge from constraints imposed by the interaction of the support surface, the task and the individual. The observed adaptations in the coordination and control of posture in response to support surface constraints evidenced in the present studies provide support for the theory of perception and the control of bodily orientation (Riccio & Stoffregen, 1988). / Graduation date: 1998
357

Fishing location choices in Oregon trawl fisheries : are fishermen risk-averse or risk-prone?

Trisak, Jiraporn 22 November 1994 (has links)
Despite the fact that fishing is an inherently uncertain business, risk has rarely been formally recognized in fisheries science or management. Few fishery management plans include any form of risk assessment and those that do focus on minimizing risk caused by uncertainty associated with markets and environmental conditions. Fishermen's attitudes towards risk, whether they are risk-neutral, risk-averse, or risk-prone, have rarely been considered. Although fishermen's attitudes towards risk have been shown in theory to have an impact on fish populations, none of the previous investigations precisely identified whether fishermen are risk-neutral, risk-averse, or risk-prone. This research attempted to identify fishermen's attitudes towards risk from an analysis of their decisions about where to fish. The research applied risk-sensitive foraging theory to an analysis of data from the Oregon trawl fishery for 1991. The data were provided by the Oregon Department of Fisheries and Wildlife. One file contained tow-by-tow information for each fishing trip on landings by species, time spent fishing, type of gear, and fishing locations. A corresponding file contained trip-by-trip information on landings and price by species. The two data files were screened for inconsistencies and then classified into small homogeneous categories based on port, fishing gear, fishing area, and boat size. Various variance-discounting models were fitted to each category to determine fishermen's attitudes toward risk. The models describe the expected utility of fishing at a given distance from port as a linear function of the mean, variance, and third moment of the dollar value per hour of the retained catch. The unknown parameters were estimated from the data using logistic regression techniques. The results of the analysis indicated that in two of fifteen categories the fishermen were risk-averse, and in four categories they were risk-neutral. However, for the remaining nine categories the results were inconclusive and in some cases the fishermen's choice of fishing locations appeared illogical. Instead of preferring fishing grounds that generated higher profits, it appeared that fishermen actively avoided such grounds. The inconclusive and sometimes illogical results may have been due to inappropriate assumptions about the data and about the factors motivating fishermen's decisions. Additionally, there might have been some factors that could have affected the analysis which this research overlooked. For example, this research only accounted for monetary rewards, but fishermen may have preferences other than revenues and costs that influence their choice of fishing grounds. / Graduation date: 1995
358

Educational risk and recidivism an exploratory analysis of court involved youth /

Russell, Christiana Modupe, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 105-117).
359

A cost effective analysis of preventative mitigation options for wildland urban interface homes threatened by wildfire

Stockmann, Keith Douglas. January 1900 (has links)
Thesis (Ph. D.)--University of Montana, 2006. / Title from title screen. Description based on contents viewed Mar. 30, 2007. Includes bibliographical references (p. 142-151).
360

Express risk assessment for the dispersion of aerosols in a urban environment using probabilistic implicit tracking

Rowan, Steven Lee. January 2006 (has links)
Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains viii, 31 p. : ill. (some col.). Includes four zip file programs. Includes abstract. Includes bibliographical references (p. 26-27).

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