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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.
341

Impact of access control and copyright in e-learning from user's perspective in the United Kingdom

Akmayeva, Galina January 2017 (has links)
The widespread adoption of E-Learning has largely been driven by the recommendations of educational technologists seeking to convey the benefits of E-Learning as a valuable accessory to teaching and possible solution for distance-based education. Research in the E-Learning domain has mainly focused on providing and delivering content andinfrastructure. Security issues are usually not taken as central concern in most implementations either because systems are usually deployed in controlled environments, or because they take the one-to-one tutoring approach, not requiring strict security measures. The scope of this research work is to investigate the impact of Access Control and Copyright in E-Learning system. An extensive literature review, theories from the field of information systems, psychology and cognitive sciences, distance and online learning, as well as existing E-Learning models show that research in E-learning is still hardly concerned with the issues of security. It is obvious that E-learning receives a new meaning as technology advances and business strategies change. The trends of learning methods have also led to the adjustment of National Curriculum and standards. However, research has also shown that any strategy or development supported by the Internet requires security and is therefore faced with challenges. This thesis is divided into six Chapters. Chapter 1 sets the scene for the research rationale and hypotheses, and identifies the aims and objectives. Chapter 2 presents the theoretical background and literature review. Chapter 3 is an in-depth review of the methods and methodology with clear justification of their adaptation and explains the underlying principles. Chapter 4 is based on the results and limitations obtained from the six case studies observations supported with literature review and ten existing models, while Chapter 5 is focused on the questionnaire survey. Chapter 6 describes the proposed Dynamic E-Learning Access Control and Copyright Framework (DEACCF) and the mapping of the threats from the Central Computing and Telecommunications Agency (CCTA) Risk Analysis and Management Method (CRAMM) to Annualised Loss Expectancy (ALE). Chapter 7 presents the conclusions and recommendations, and the contribution to knowledge with further development plans for future work.
342

Reliability assessment of safety instrumented systems subject to process demand

Alizadeh, Siamak January 2018 (has links)
Industry and society are now aware of risk more than ever before. Organisations whose activities pose risk to individuals and society are accountable to manage and reduce risk to an acceptable level. In this regard, utilisation of Safety Instrumented Systems (SISs) as an independent protection layer is a practical method of achieving the required risk reduction. The role of a SIS is to maintain the safety of equipment under control by providing a safety-related function. The International Standards, IEC 61508/61511, provide a set of guidelines to promote consistency for implementation of SISs used for risk reduction. In accordance with IEC 61508, the performance of a SIS shall be established by computing the associated Probability of Failure on Demand (PFD) as a reliability measure using a suitable technique. The principal purpose of this research is to provide the basis for reliability assessment of redundant SISs affected by process demand as well as component failures. This dissertation introduces four new reliability models for redundant SISs subject to process demand for the first time using Markov analysis technique. The proposed reliability models 1 and 3 incorporates process demands in conjunction with Common Cause Failure (CCF) and evaluates their impacts on the reliability quantification of 1oo2 redundant configuration using different repair philosophies. In model 3, the proposed Markov model was also compared with the IEC 61508 approach for redundant SISs and a reliability improvement between 9% - 15% were observed. The model 2 on the other hand integrates the Dangerous Detected (DD) failure rates in the unavailability assessment of redundant SISs subject to process demand assuming that CCF does not occur. An additional reliability model was developed in this research for a 1oo3 redundant configuration subject to process demand excluding CCF and its construction was verified using partial verification method. Furthermore, a generic framework for reliability assessment of 1oon redundant SISs is provided in this thesis in conjunction with some guidelines for future researchers as how to conduct reliability assessment of SISs subject to process demands. The accuracy of the proposed Markov models is verified for industrial application case studies. It is demonstrated that the proposed approach provides a sufficiently robust result for all demand rates, demand durations, common cause failures, dangerous detected and undetected failure and associated repair rates for SISs. The effectiveness of the proposed models offers a robust opportunity to conduct reliability assessment of redundant SISs subject to process demands.
343

Optimal dynamic portfolio selection under downside risk measure.

January 2014 (has links)
传统的风险控制以终端财富的各阶中心矩作为风险度量,而现在越来越多的投资模型转向以不对称的在某个特定临界值的下行风险作为风险度量。在现有的下行风险中,安全第一准则,风险价值,条件风险价值,下偏矩可能是最有活力的代表。在这篇博士论文中,在已有的静态文献之上,我们讨论了以安全第一准则,风险价值,条件风险价值,下偏矩为风险度量的一系列动态投资组合问题。我们的贡献在于两个方面,一个是建立了可以被解析求解的模型,另一个是得到了最优的投资策略。在终端财富上加上一个上界,使得我们克服了一类下行风险投资组合问题的不适定性。引入的上界不仅仅使得我们的下行风险下的投资组合问题能得到显式解,而且也让我们可以控制下行风险投资组合问题的最优投资的冒险性。用分位数法和鞅方法,我们能够得到上述的各种模型的解析解。在一定的市场条件下,我们得到了对应的拉格朗日问题的乘子的存在性和唯一性, 这也是对应的鞅方法中的核心步骤。更进一步,当市场投资组合集是确定性的时候,我们推出解析的最优财富过程和最优投资策略。 / Instead of controlling "symmetric" risks measured by central moments of terminal wealth, more and more portfolio models have shifted their focus to manage "asymmetric" downside risks that the investment return is below certain threshold. Among the existing downside risk measures, the safety-first principle, the value-at-risk (VaR), the conditional value-at-risk (CVaR) and the lower-partial moments (LPM) are probably the most promising representatives. / In this dissertation, we investigate a general class of dynamic mean-downside risk portfolio selection formulations, including the mean-exceeding probability portfolio selection formulation, the dynamic mean-VaR portfolio selection formulation, the dynamic mean-LPM portfolio selection formulation and the dynamic mean-CVaR portfolio selection formulation in continuous-time, while the current literature has only witnessed their static versions. Our contributions are two-fold, in both building up tractable formulations and deriving corresponding optimal policies. By imposing a limit funding level on the terminal wealth, we conquer the ill-posedness exhibited in the class of mean-downside risk portfolio models. The limit funding level not only enables us to solve dynamic mean-downside risk portfolio optimization problems, but also offers a flexibility to tame the aggressiveness of the portfolio policies generated from the mean-downside risk optimization models. Using quantile method and martingale approach, we derive optimal solutions for all the above mentioned mean-downside risk models. More specifically, for a general market setting, we prove the existence and uniqueness of the Lagrangian multiplies, which is a key step in applying the martingale approach, and establish a theoretical foundation for developing efficient numerical solution approaches. Furthermore, for situations where the opportunity set of the market setting is deterministic, we derive analytical portfolio policies. / Detailed summary in vernacular field only. / Zhou, Ke. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves i-vi). / Abstracts also in Chinese.
344

Risk Factors and Outcomes of Bloodstream Infection

Aliyu, Sainfer Elizabeth January 2017 (has links)
This dissertation examines risk factors and outcomes associated with bloodstream infection (BSI). In Chapter One, the problems of BSI are introduced and their significance described. In Chapter Two, the results of a systematic review and meta-analysis synthesizing the prevalence of one of the most rapidly emerging causes of BSI among nursing home residents, multidrug resistant-gram negative bacteria are described. In Chapter Three, a retrospective cohort study identifying the prevalence and risk factors for BSI present on hospital admission (POA) is reported, including an assessment of antimicrobial resistance in isolates causing BSI-POA by admission source (i.e. private homes, other hospitals and skilled nursing facilities). In Chapter Four, a retrospective cohort study explaining risks for hospital-associated infections (HAIs) among the BSI-POA cohort is described. Length of stay and mortality among patients with a BSI-POA who develop HAI and those who do not are reported. Finally, in Chapter Five, findings of the previous chapters are synthesized and the conclusion is provided including strengths, limitations and implications for policy and practice.
345

Avaliação do risco de intoxicação por vapores de mercúrio / Assessment of the risk of mercury poisoning

Sergio Colacioppo 20 October 1976 (has links)
O mercúrio, devido a suas propriedades físicas e químicas peculiares, é utilizado em grande número de atividades humanas, representando assim uma parcela significativa na economia de diversos paises. Por outro lado, o mercúrio possue propriedades tóxicas e que associadas à periculosidade dos seus vapores ou a dos resíduos industriais, representa considerável risco à saúde do trabalhador e dos moradores das adjacencias de indústrias que lidam com este metal. O mercúrio pode apresentar-se no meio ambiente sob várias formas, sendo que na forma metálica é que representa maior problema de saúde ocupacional, devido a formação de vapores inodoros e incolores - que possuem grande facilidade de penetração e absorção por via respiratória. Assim o mercúrio na forma de vapor mereceu maior atenção neste estudo. Nao se têm até o presente completamente esclarecido o mecanismo da ação tóxica do mercúrio no organismo humano, havendo ainda algumas contradições e divergências na interpretação de resultados laboratoriais de pesquisa do metal em urina, sangue, cabelos e outros meios biológicos, ou ainda das determinações de alterações metabólicas produzidas pela ação do mercúrio no organismo humano. Uma avaliação do risco de intoxicação profissional por vapores de mercúrio, representada pela determinação dos níveis de vapor de mercúrio num ambiente de trabalho, além da avaliação do risco em si, auxilia o médico no diagnóstico da intoxicação, bem como\'o engenheiro a testar a eficiência das medidas preventivas existentes. Ao planejar uma avaliação ambiental, de vapores de mercúrio o higienista industrial depara-se na bibliografia especializada, com processos diversos de captação e análise e sem indicação da eficiência na grande maioria. Foi então realizado um estudo comparativo entre os processos, mais viáveis, dois deles utilizando absorção em solução ácida de permanganato de potássio e solução de iôdo e outros dois utilizando adsorção com carvão ativo e com hopcalita. Para efeito de realização do estudo acima referido fez-se necessária a construção de equipamento que fornecesse uma atmosfera padrão de vapores de mercúrio - proposto e descrito no presente trabalho - foi fixado igualmente o processo analítico, tendo sido escolhido o de absorção atômica sem chama devido à sua alta sensibilidade, acuidade e precisão. As concentrações produzidas foram ligeiramente superiores à preconizada pela ACGIH como limite de tolerância e o processo que maior confiabilidade apresentou foi o que utiliza solução ácida de permanganato de potássio sendo o de maior acuidade e precisão. / Due to its peculiar physical and chemical properties, mercury is applied in a great nurnber of human activities and represents a significative portion of the economy of several countries. On the other hand mercury has some toxic properties that, when associated to its hazardous vapours or to industrial wastes becomes a considerable risk to the health of workers from industries that deal with it or the neighbouhood dwellers. Mercury can be found under several forms: the metalic one is the main problem to occupational health, specially when there is occurrence of mercury vapour - inodorous and uncoulored - easily absorbed by the respiratory tract. Thus, mercury vapour deserved our attention in this paper. The toxic action of mercury in human beings is not completely known yet for there are still some contradictions and divergencies about the interpretation of laboratorial findings of the metal in urine blood, hair and other biological samples as well as about the establishment of a threshould limit for metabolic alterations caused by the mercury in human organism. An evaluation of professional intoxication risk due to mercury vapour by measuring its level in a work area will help the physician to diagnosticate the intoxication and the engineer to test the eficacy of the existing preventive measures. When planning an environmental evaluation of the mercury vapour, the industrial hygienist can find different processes of collection and analysis in the specialized bibliography, most of them without any evidence of its effectiveness. A comparative study was then carried out on the most useful processes, two of them applying absortion in acid solution potassium permanganate and iodine solution, and the two others making use of adsortion with active charcoal and hopcalite. To fulfil the above mentioned study, it was necessary to buil up an equipment that could provide a standard atmosphere of mercury vapour (proposed and described here). The analitic process of flameless atomic absortion was chosen due to its high sensibility ando accuracy. The concentrations produced were slightly superior to the ones professed by the ACGIH as the threshol limit, and it was found that the most reliable process was the acid solution of pottassium permanganate, for its accuracy and eficiency.
346

Implementation of violence risk assessments into forensic psychiatric care in Scotland

Vojt, Gabriele January 2014 (has links)
Background. A central role of mental health professionals within the criminal justice and forensic mental health system is the assessment, management and communication of an individual's risk of future violence (Webster & Hucker, 2007). The current methodology favoured by clinicians is the structured professional judgement (SPJ) approach (Farrington, Joliffe & Johnstone, 2008). These instruments act as guides in clinical practice in that practitioners are encouraged to apply clinical judgement on the relevance of empirically validated risk factors to each client. In this way, identified risk factors can be directly used to inform individual care and treatment, i.e. risk management. Yet, research on SPJ tools is typically based on retrospective or pseudo-prospective designs, which lack in ecological validity. Furthermore, findings are based on risk assessments completed by researchers rather than clinicians. This is an issue as risk ratings differ significantly depending on professional background (de Ruiter & de Vogel, 2004). Aims. This thesis presents five studies with the aim of examining the link between violence risk assessment and management in vivo. This includes two studies focussing on the predictive validity of SPJ tools following clinical implementation; a description of the implementation procedure; a traditional research study on the predictive power of dynamic risk factors and a pilot evaluation of a short term risk assessment tool for imminent inpatient violence. Methodology. The primary research site was the State Hospital, the high secure psychiatric facility for mentally disordered offenders in Scotland and Northern Ireland. The research population consisted of 115 male forensic patients who were followed up across different risk settings for a mean of 31 months. The SPJ instruments under investigation were the HCR-20 (Webster et al, 1997), the SVR-20 (Boer, Hart, Kropp et al, 1997) and the RSVP (Hart et al, 2003). All assessments were exclusively completed by clinicians and resulted in active risk management strategies. Additionally, the predictive validity of dynamic risk factors was examined through psychometric measures of anger, impulsivity, psychiatric symptoms, unmet needs and imagined violence. The risk of imminent violence was assessed with the Dynamic Appraisal Situational Appraisal - Inpatient Version (DASA-IV, Ogloff & Daffern, 2006). Results and Conclusions. Findings indicate that clinically implemented SPJ tools are not predictive of future violence, both within and outwith secure settings. Comparison with a previous study at the State Hospital implies that the implementation process of the HCR- 20 facilitated the knowledge transfer from assessment to management, and therefore incidents were prevented. This noted the results also highlight that clinicians may accept risk tools into practice when these have not been scientifically scrutinised. This was the case with the RSVP in that there is little published data on the psychometric properties of this tool, yet its introduction replaced the SVR-20 across the State Hospital. With regards to dynamic risk factors, the severity and chronicity of psychiatric symptoms were the strongest predictors of violence. This is further corroborated by the finding that the DASA-IV predicted violence within 24 hours of ratings provided. All findings are discussed in the context of previous research and the experienced obstacles of implementing changes within NHS settings. Clinical implications and recommendations for violence assessment and management are provided in the light of acknowledged limitations.
347

Navigating risk in home visitation: An examination of the predictive validity of the Healthy Families Parenting Inventory

January 2018 (has links)
abstract: Child abuse and neglect is a devastating yet preventable social problem. Currently, early childhood home visitation services are the primary approach to preventing maltreatment and improving child well-being in the United States. However, existing literature suggests that improvement is needed regarding how home visitation professionals identify and respond to risk factors for child abuse and neglect. Although there is substantial multidisciplinary literature that investigates the utility of standardized measures to determine future risk for maltreatment, there has been minimal inquiry into the validity of early childhood home visitation assessment instruments to accurately identify and classify children and their families by their risk for future maltreatment. In response to the dearth in the literature, the purpose of this dissertation was to examine the utility of the Healthy Families Parenting Inventory (HFPI) to predict a family’s risk for future maltreatment. Families enrolled in Healthy Families Arizona, a child abuse and neglect prevention program, were followed for 12 months after the completion of the baseline HFPI to measure if the family had received an investigation of maltreatment from the public child welfare system. Bivariate results indicated that the generated risk classifications of the HFPI and the overall total composite score were related to the occurrence of a future maltreatment investigation. Specifically, the results from the binary logistic regression models provided evidence that as a family’s score increased on the inventory, the likelihood of receiving an investigation of maltreatment decreased. Further, significant relationships were found between a family’s score on several individual items of the HFPI and the occurrence of a maltreatment investigation. This dissertation concludes with a discussion of potential avenues of research on the topic of risk assessment in prevention programs serving at-risk families. / Dissertation/Thesis / Doctoral Dissertation Social Work 2018
348

Design thinking in healthcare : developing patient-centred communication materials for breast cancer detection

Beaumont, Corrine Ellsworth January 2011 (has links)
This thesis is the culmination of five years of communication design research (2006 – 2010) on a specific area of healthcare—breast cancer detection and screening. It is a project-­‐based doctoral work, underpinned by a practice-­‐led research journey of a graphic designer. The result is this written thesis with an accompanying set of uniquely designed objects: • a series of posters on breast cancer detection • an educational leaflet and risk assessment form • a series of working website prototypes (see worldwidebreastcancer.com) This thesis offers an in-­‐depth case study that demonstrates and contextualises the need for using communication design in patient engagement and education efforts in order to create a more patient-­‐centred experience in breast cancer detection. The significant contributions of this thesis are: • the development of a human-­‐centred design thinking methodology, known as the ‘USER’ model, which helps a designer develop a product for use within a system in an iterative, intuitive and analytical way. This is the first design thinking model of its kind to embed a framework for analysing objects within a systems framework; • the production and testing of visual metaphor, which was found to improve patient literacy and confidence. The significance of this has been to increase the potential for symptoms to be reported early and decrease mortality rates; • a map illustrating the patient journey of breast cancer screening that illustrates roles, communications and detection activities. This has been developed for general practices and imaging centres in a visually clear and distinct way; • a risk assessment tool that encourages doctors and patients to engage in collaborative decision-­‐making in the planning of breast cancer screening activities. Finally, the work presented here has profound implications for future studies of patient engagement and health literacy in breast cancer detection. The research journey, findings and objects in this thesis may lead to improved patient communication experiences and decreased mortality in breast cancer. This thesis also acts as a model for exploring and developing design solutions for other health causes.
349

Risk Factors for Suicidal Behavior among Bhutanese Refugees Resettled in the United States

Meyerhoff, Jonah 01 January 2019 (has links)
Suicidal behavior and death by suicide are significant and pressing problems in the Bhutanese refugee community. Currently, Bhutanese refugees are dying by suicide at a rate nearly 2 times higher than the general United States population. Proper identification of risk factors for suicide saves lives and prevents suicides (Mann et al., 2005); however, if suicide risk is underestimated due to culturally inflexible risk assessments, preventable deaths may continue to needlessly grow. In a community sample of Bhutanese refugees resettled in Vermont (N=60), the current study aims to (1) test elements of a comprehensive conceptual model of incremental risk factors for suicide – adapted from the interpersonal psychological theory of suicide (IPTS; Joiner, 2005) – including suicidal desire, suicidal ideation, thwarted belongingness, and perceived burdensomeness and (2) test the relative contributions of suicidal desire and suicidal ideation as risk factors for suicidal behavior. Participants attended a single study visit at which they completed self-report measures administered in an interview format via an interpreter, if needed. Key measures included the Beck Scale for suicidal ideation (BSS; Beck & Steer, 1991), Interpersonal Needs Questionnaire (INQ; Van Orden et al., 2012), Wish to be Dead Scale (WDS; Lester, 2013), Refugee Health Screener – 15 (RHS-15; Hollifield et al., 2013), Postmigration Living Difficulties checklist (PmLD; Laban et al., 2005), Brief Biosocial Gambling Screen (BBGS; Gebauer et al., 2010), basic demographics questions, and qualitative questions about suicide within the Bhutanese refugee community. The analytic approach relied on the use of hurdle models, Fisher’s exact tests, hierarchical logistic regression, and independent samples t-tests to assess the relationships among aspects of our conceptual model. Although endorsement of suicidal ideation (n = 4, 6.7%) and suicidal behavior (n = 2, 3.3%; measured by combining the planning and concealment subscales of the BSS) was low in the sample, a substantial minority (n = 29, 48.3%) endorsed some desire to be dead. Perceived burdensomeness, but not thwarted belongingness, was significantly associated with both suicidal ideation and the desire to be dead. There was no evidence that the desire for death contributed additional risk of suicidal behavior, above and beyond suicidal ideation. Of participants with a history of suicide attempts (n = 4), none reported any suicidal ideation and 3 reported some desire to be dead. Neither desire to be dead nor suicidal ideation was significantly related to suicide attempt history. These findings have implications for suicide detection and prevention among resettled Bhutanese refugees. The cultural responsiveness of suicide screening in this population could be improved by assessing two constructs not typically assessed: desire to be dead (e.g., the WDS) and perceived burdensomeness (e.g., INQ). Explicit evaluation of these two constructs in Bhutanese refugees may increase the sensitivity of risk assessments without sacrificing specificity in comparison to assessments exclusively focused on self-reported suicidal ideation.
350

Towards the development of a comprehensive risk assessment methodology for building and transport fires

Blackmore, Jane, Safety Science, Faculty of Science, UNSW January 2004 (has links)
Over the centuries, the assessment of risk has become an integral part of the decision process. Assessment techniques have developed to meet different applications, but all have problems and none is entirely suited to the assessment of risks relating to fire. This dissertation examines the development of risk assessment processes and frameworks, identifying common features and problems and key differences in approach. Despite generically similar approaches, different applications have led to the development of many different paradigms, none of which appears to be entirely suitable for application to building and infrastructure fires. Current fire risk assessment methods which incorporate important advances in fire modelling and Monte Carlo simulation, rely on a fire engineering approach. They tend to consider only the limited range of fire safety systems that are directly involved in construction, failing to address many of the procedural and other activities that can overwhelm traditional controls, and taking insufficient account of interactions between different controls and the factors that influence them. Further, comparative risk levels are generally evaluated against the ill-defined scenario of current practice, as defined in outdated prescriptive regulations. The result is that catastrophic consequences continue to occur, despite the presence of traditionally accepted controls. The problem is to find a framework that evaluates the sensitivity of levels of risk in fire against a defined, uncontrolled state, taking into account the effects of a comprehensive range of factors and controls. A new approach to risk assessment that addresses a comprehensive set of factors and controls and evaluates the event without, and with, controls, is considered. The framework, together with the steps for its implementation, appears to provide a versatile and flexible method of risk assessment. It is likely that the framework can be applied to all risk assessment situations. A study is undertaken to investigate the impact of factors and interactions that are not commonly taken into account in fire risk assessment. The chosen situation is a fire in the driver???s cab of a train. Current driver procedures are examined, and fire growth rates for specified materials are considered. Using the fire spread model CFAST, conditions in the cab for a range of ventilation conditions and fire growth rates are calculated. Threshold levels that determine response times for engineered and human controls and tenability, and common factors that influence consequences, can play a critical role in modelling the decision process. A driver???s decision model is proposed that determines the impact of the driver???s decisions to adjust ventilation by opening or closing windows and doors, and to extinguish the fire. The model takes into account time to respond and time to perform the necessary activities. The study shows that, even with a limited choice of actions, the decisions of the driver can have a critical effect on the outcome of a fire in the driver???s cab, altering the situation from a controlled to an uncontrolled state. Recommendations are made for further development of the new risk assessment framework, and for the development of fire modelling for risk assessment purposes. Finally, recommendations are made for the continuation of the development of the train driver response model that would result in the generation of driver decision support software.

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