The United Kingdom’s Civil Aviation Authority published the national aviation forecast in 2008. The forecast predicts that domestic traffic will increase by 3.5% per year, and that international traffic will grow, on average, by 4.5% during 2010-2020. Based on this prediction, the traffic density will increase dramatically in the future, and airspace will be more and more congested. Usually, there are two potential solutions to deal with this situation: improving the ability of air traffic flow management is one solution; reducing the separation minimum of aircraft is another solution. However, this thesis focuses on the second solution, based on constraints of communication, navigation and surveillance systems (CNS). Cont?d.

This thesis sets out research carried out to investigate the usefulness of a descriptive database of construction methods for safety assessment. In addition, it investigates the possibility of utilising construction images as sources of safety related information. / The construction industry has been recognized as a hazardous work environment with a high accident rate for years, hence, site safety is a problem. Nowadays, the use of construction images in the form of photographs is commonplace and they are used as sources of information. The literature review reveals that they have never been used as sources of information concerning construction safety practice. / A preliminary investigation is conducted to study the possibility of utilizing construction images as sources of safety related information. The findings revealed that it is possible to use construction images as sources of information for construction safety assessment however, there were problems related to image interpretation and dissimilar safety judgment. It was assumed that those problems were arising from lack of safety knowledge and experiences, also no safety assessment method existed that could be used when using images as sources of information. / To overcome problem related to the existence of safety assessment method, the research developed a method to assess safety by using information observed from images. As a similar safety judgment would be obtained from a same guideline therefore, a safety guideline was established, including safety checklist and safety scores. To give meaning of sets of safety score, two methods of conditional probability approach from Artificial Intelligence that quantitatively deal with uncertainty, the Bayes’ Theorem and the Fuzzy Logic Theory, were employed. The Bayes’ Theorem formula was adopted for calculating a likelihood of a hypothesis being true based on evidence or P(H/E). The hypothesis used in this research that a safe construction practice being used. The evidence used to test this hypothesis is information collected from construction images. This method allows construction practices shown in the images to be defined as having a high level of safety or low level of safety. / The construction practices with low level of safety do not need to analysed further. Fuzzy logic theory can then be used for further classifying those images identified as having a high level of safety into one of three classifications: “most likely safe”, “fairly safe” or “most likely unsafe”. / To overcome problem related to lack of safety knowledge and safety experience, one method of reasoning based on reuse past experience was employed, called the Case- Based Reasoning (CBR). The CBR method will allow safety information stored in database to be reused for reasoning process to give safety scores. As CBR works based on stored information from database therefore an image database has to be developed. / Following works (or researches) have been done to overcome problems revealed from preliminary investigation therefore those works have to organize in a structured and systematic system. The research was developed a safety assessment system called SAFE AS. / The safety assessment system worked in two processes, manual calculation and information storage into database. Manual calculation worked as follows: First, a construction practice judgment is given based on image data, safety checklist and using safety scores provided. Secondly, a construction practice is defined into one of two definitions provided: a high-level and a low-level of safety based on Bayes’ Theorem formula and given safety scores. Third, a high-level of safety of construction practice is classified into one of three classifications: most likely safe, fairly safe and most likely unsafe, which are developed, based on fuzzy sets formula. Following manual calculation process, the result from the process then become an input for the second process: information storage. All information of images and their safety practices are stored in an image database. These two processes are done separately and manually. / Problem is arising from manual safety assessment system, that the processes are time-consuming. To overcome this problem, even to make a safety assessment system practically more benefit, the system is developed in a Web-based system, which allows safety assessment process and information storage process done comprehensively and automatically. All users can share their safety knowledge and experiences, and reuse stored experience as a basis of reasoning process from anywhere. / As a result, the research has developed a Web-based safety assessment system to show how to utilize construction images to assess safe construction practice, store information from assessment process, and reuse this information for safety knowledge enhancement. Two experiments using 69 images and a set of detailed images have confirmed the application of a Web-based safety assessment system and verified its reliability. / Another benefit from the safety assessment system is the safety likelihood scores obtained, which can be used to detect safety trends that are developing in construction project over time. These trends were used to predict the likely safety of the construction practices in use on the project in future so it can be used as indicators to monitor and control safety in construction projects. With this process construction images can be used as sources of safety related information and the safety assessment system can be used in future for predicting, monitoring and controlling of on-site safety. / Areas needing future research are suggested, including providing advance search features in the assessment system to retrieve closer relevant cases for case-based reasoning and automated hazard recognition and identification feature to avoid accident occurrence as the result of human carelessness.

Made available in DSpace on 2014-06-12T15:59:55Z (GMT). No. of bitstreams: 2 arquivo5803_1.pdf: 2496332 bytes, checksum: b4666e127bf620dbcb7437f9d83c2344 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco / A análise da segurança (Safety Assessment) é um processo bem conhecido que serve para garantir que as restrições de segurança de um sistema crítico sejam cumpridas. Dentro dele, a análise de segurança quantitativa lida com essas restrições em um contexto numérico (probabilístico). Os métodos de análise de segurança, como a tradicional Fault Tree Analysis (FTA), são utilizados no processo de avaliação da segurança quantitativo, seguindo as diretrizes de certificação (por exemplo, a ARP4761 Guia de Práticas Recomendadas da Aviação). No entanto, este método é geralmente custoso e requer muito tempo e esforço para validar um sistema como um todo, uma vez que para uma aeronave chegam a ser construídas, em média, 10.000 árvores de falha e também porque dependem fortemente das habilidades humanas para lidar com suas limitações temporais que restringem o âmbito e o nível de detalhe que a análise e os resultados podem alcançar. Por outro lado, as autoridades certificadoras também permitem a utilização da análise de Markov, que, embora seus modelos sejam mais poderosos que as árvores de falha, a indústria raramente adota esta análise porque seus modelos são mais complexos e difíceis de lidar. Diante disto, FTA tem sido amplamente utilizada neste processo, principalmente porque é conceitualmente mais simples e fácil de entender. À medida que a complexidade e o time-to-market dos sistemas aumentam, o interesse em abordar as questões de segurança durante as fases iniciais do projeto, ao invés de nas fases intermediárias/finais, tornou comum a adoção de projetos, ferramentas e técnicas baseados em modelos. Simulink é o exemplo padrão atualmente utilizado na indústria aeronáutica. Entretanto, mesmo neste cenário, as soluções atuais seguem o que os engenheiros já utilizavam anteriormente. Por outro lado, métodos formais que são linguagens, ferramentas e métodos baseados em lógica e matemática discreta e não seguem as abordagens da engenharia tradicional, podem proporcionar soluções inovadoras de baixo custo para engenheiros. Esta dissertação define uma estratégia para a avaliação quantitativa de segurança baseada na análise de Markov. Porém, em vez de lidar com modelos de Markov diretamente, usamos a linguagem formal Prism (uma especificação em Prism é semanticamente interpretada como um modelo de Markov). Além disto, esta especificação em Prism é extraída de forma sistemática a partir de um modelo de alto nível (diagramas Simulink anotados com lógicas de falha do sistema), através da aplicação de regras de tradução. A verificação sob o aspecto quantitativo dos requisitos de segurança do sistema é realizada utilizando o verificador de modelos de Prism, no qual os requisitos de segurança tornam-se fórmulas probabilísticas em lógica temporal. O objetivo imediato do nosso trabalho é evitar o esforço de se criar várias árvores de falhas até ser constatado que um requisito de segurança foi violado. Prism não constrói árvores de falha para chegar neste resultado. Ele simplesmente verifica de uma só vez se um requisito de segurança é satisfeito ou não no modelo inteiro. Finalmente, nossa estratégia é ilustrada com um sistema simples (um projeto-piloto), mas representativo, projetado pela Embraer

O desenvolvimento de novos modelos de pele e novas metodologias in vitro segue uma tendência mundial na busca pela redução ou substituição de testes em animais. Nesse contexto, kits de epiderme humana reconstruída (RHE) apresentam-se como uma plataforma promissoras para essa proposta e, alguns modelos encontram-se validados para ensaios de irritação e corrosão cutânea in vitro. Entretanto, em países como o Brasil, enfrentam-se questões alfandegárias e perda do material por perecibilidade, dificultando e até impedindo, a importação desses kits para utilização por parte das indústrias e laboratórios nacionais. Em contrapartida, o desenvolvimento de um modelo de RHE apresenta-se como um avanço tecnológico e ganho de autonomia para esses países. Assim, no capítulo 1 explorou-se o desenvolvimento de um modelo nacional de RHE (USP-RHE) que atendesse às exigências internacionais descritas no guia OECD 439. O modelo desenvolvido apresentou uma epiderme bem diferenciada e atendeu aos parâmetros de qualidade (histologia, viabilidade e função barreira) bem como da funcionalidade, a qual é expressa na capacidade de distinção entre irritantes e não irritantes, apresentando 85,7% de especificidade, 100% sensibilidade e 92,3% de acurácia quando comparada com a classificação in vivo obtida pelo ensaio do linfonodo local (LLNA). No capítulo 2, células monocíticas THP-1 em monocamada foram capazes de distinguir entre agentes sensibilizantes e não sensibilizantes por meio da expressão de CD86, CD54 e liberação de IL-8. Após a obtenção de RHE e THP-1 funcionais, um cross-talking foi estabelecido gerando uma RHE imunocompetente. A RHEI distinguiu satisfatoriamente entre agentes sensibilizantes e não sensibilizantes por meio da expressão de CD86 e CD54 na membrana das células THP-1. A liberação de IL-8 também foi avaliada na RHEI, mas, não demonstrou ser um bom indicador para a avaliação de sensibilização, ao contrário de IL-1α, que distinguiu satisfatoriamente agentes sensibilizantes de não-sensibilizantes, mas não foi capaz de hierarquizá-los. No capítulo 3, avaliou-se o papel de interleucinas do tipo Th2 e da depleção de colesterol na membrana plasmática no desenvolvimento de características morfológicas e moleculares da dermatite atópica (DA) in vitro em um modelo de RHE. Os resultados demonstram que o uso de IL-4, IL-13 e IL-25 em combinação com a depleção de colesterol na membrana plasmática mimetiza in vitro, as principais características da DA. No capítulo 4, buscou-se avaliar os efeitos imunossupressores da radiação ultravioleta na RHEI. Os ensaios foram realizados em diferentes períodos de exposição, entretanto, não foi possível observar tais efeitos. Os resultados justificam-se pela ausência da liberação de IL-10 pelo RHE imunocompetente, por exemplo, e demonstram uma limitação do RHE imunocompetente para avaliações de inativação da reposta imune. Neste trabalho, concluímos que foi possível obter uma RHE competitiva, similar aos modelos internacionais validados e que pode ser utilizada como plataforma para ensaios de irritação e sensibilização cutânea, além de ser uma plataforma para estudos da dermatite atópica. No modelo é possível estudar a ativação do sistema imune, o que o torna promissor como uma plataforma para avaliação de resposta imunológica in vitro. Conclui-se, portanto, que os objetivos foram amplamente atendidos além de oferecermos um protocolo de livre acesso para reprodução por outros laboratórios e um modelo para validação futura. / The development of new in vitro skin models and new methodologies follows a global trend in search for reductions or replacement of animal testing. In this context, Reconstructed Human Epidermis kits (RHE) are presented as a promising platform in the search for alternative methods to animal use, and some models are validated for skin irritation and corrosion in vitro tests. However, in countries such as Brazil, who face customs issues and loss of material due to perishability, making it challenging and even compromising the importation of these kits for use by industries and laboratories. In contrast, the development of an RHE model is presented as a technological breakthrough and gain of autonomy for these countries. Thus, in Chapter 1 we explored the development of a national model of RHE (USP-RHE) that meet international requirements described in OECD TG 439. The developed model presented a well-differentiated epidermis and met the quality parameters, for instance, histology, viability, and barrier function as well as the functionality expressed in the capacity of screening between irritants and nonirritants, with 85.7 % of specificity, 100 % of sensitivity and 91.7% of accuracy in comparision to in vivo UN GHS classification from Local limph node assay (LLNA). In chapter 2, monocytic THP-1 cell line, as monolayers, were able to distinguish between sensitizers and non-sensitizers by expression of CD86, CD54, and IL-8 release. In this model, functional RHE and THP-1 were used in a cross-talking, and thus an immunocompetent RHE (RHEI) was generated. The RHEI has distinguished satisfactorily between sensitizers and non-sensitizers through CD86 and CD54 expression that was larger and more sensitive in this model. The release of IL-8 was also evaluated in RHEI, however, did not demonstrate to be a good parameter for this evaluation, unlike IL-1α, which satisfactorily distinguished sensitizers from non-sensitizers, but was not able to hierarchize them. In chapter 3, we evaluated the role of Th2-related cytokines and plasma membrane cholesterol depletion (CD) in the development of atopic dermatitis (AD) morphological and molecular characteristics in an in vitro model of RHE. The results showed that combination of IL-4, IL-13 and IL-25 in combination with CD can reproduce the major features of AD in vitro. In Chapter 4, we sought to evaluate the ultraviolet radiation-induced immunosuppressive effects in RHE. The tests were performed at different times. However, it was not possible to observe such effects. The results are justified by the absence of IL-10 release by RHEI, for example, and show a limitation of RHEI for rating inactivation of the immune response. In this work, we conclude that it was possible to obtain a competitive RHE similar to the validated international models that can be used as a platform for irritation and skin sensitization tests, besides being a platform for the study of atopic dermatitis. Using this model is possible to explore the activation of immune system, which makes it promising as a platform for the evaluation of immune response in vitro. We conclude, therefore, that the objectives have been met as well as it is offering an open source protocol for breeding by other laboratories, thus offering the RHE model developed here for future validation tests.

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京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20344号 / 工博第4281号 / 新制||工||1663(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 白土 博通, 教授 八木 知己, 教授 KIM Chul-Woo, 教授 杉浦 邦征 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Safety and risk assessment are key priorities for nuclear power plants. Probabilistic risk assessment (PRA) is a method for quantitative evaluation of accident risk, in particular severe nuclear core damage and the associated release of radioactive materials into the environment. The reliability and certainty of PRA have at times been questioned, especially when real-world observations have indicated that the frequency of nuclear accidents is higher than the probabilities predicted by PRA. This thesis provides a philosophical review of the epistemic uncertainties in PRA, using the Fukushima Daiichi accident of March 2011 as a case study. The thesis provides an overview of the PRA model structure, its key elements, and possible sources of uncertainty, in an attempt to understand the deviation between the real frequency of nuclear core-melt accidents and the probabilities predicted by PRA.The analyses in this thesis address several sources of epistemic uncertainty in PRA. Analyses of the PRA approach reveal the difficulty involved in covering all possible initiating events, all component and system failures, as well as their possible combinations in the risk evaluations. This difficulty represents the source of a characteristic epistemic uncertainty, referred to as completeness uncertainty. Analyses from the case study (the Fukushima Daiichi accident) illustrate this difficulty, as the PRA failed to identify a combined earthquake and tsunami, with the resultant flooding and consequent power failure and total blackout, as an initiating causal event in its logic structure.The analyses further demonstrate how insufficient experience and knowledge, as well as a lack of empirical data, lead to incorrect assumptions, which are used by the model as input parameters to estimate the probabilities of accidents. With limited availability of input data, decision-makers rely upon the subjective judgements and individual experiences of experts, which adds a further source of epistemic uncertainty to the PRA, usually referred to as input parameter uncertainty. As a typical example from the case study, the Fukushima Daiichi accident revealed that the PRA had underestimated the height of a possible tsunami. Consequently, the risk mitigation systems (e.g. the barrier seawalls) built to protect the power plant were inadequate due to incorrect input data.Poor assumptions may also result in improper modeling of failure modes and sequences in the PRA logic structure, which makes room for an additional source of epistemic uncertainty referred to as model uncertainty. For instance, the Fukushima Daiichi accident indicated insufficient backup of the power supply, because the possibility of simultaneous failure of several emergency diesel generators was assumed to be negligibly small. However, that was exactly what happened when 12 out of the 13 generators failed at the same time as a result of flooding.Furthermore, the analyses highlight the difficulty of modeling the human interventions and actions, in particular during the course of unexpected accidents, taking into account the physiological and psychological effects on the cognitive performance of humans, which result in uncertain operator interventions. This represents an additional source of epistemic uncertainty, usually referred to as uncertainty in modeling human interventions. As a result, there may be an increase in the probability of human error, characterized by a delay in making a diagnosis, formulating a response and taking action. Even this statement confirms the complexity of modelling human errors. In the case of the Fukushima Daiichi accident, lack ofvsufficient instructions for dealing with this "unexpected" accident made the coordination of operators' interventions almost impossible.Given the existence of all these sources of epistemic uncertainty, it would be reasonable to expect such a detected deviation between the real frequency of nuclear core-melt accidents and the probabilities predicted by PRA.It is, however, important to highlight that the occurrence of the Fukushima Daiichi accident could lie within the uncertainty distribution that the PRA model predicted prior to the accident. Hence, from the probabilistic point of view, the occurrence of a single unexpected accident should be interpreted with care, especially in political and commercial debates. Despite the limitations that have been highlighted in this thesis, the model still can provide valuable insights for systematic examination of safety systems, risk mitigation approaches, and strategic plans aimed at protecting the nuclear power plants against failures. Nevertheless, the PRA model does have development potentials, which deserves serious attention. The validity of calculated frequencies in PRA is restricted to the parameter under study. This validity can be improved by adding further relevant scenarios to the PRA, improving the screening approaches and collecting more input data through better collaboration between nuclear power plants world-wide. Lessons learned from the Fukushima Daiichi accident have initiated further studies aimed at covering additional scenarios. In subsequent IAEA safety report series, external hazards in multi-unit nuclear power plants have been considered. Such an action shows that PRA is a dynamic approach that needs continuous improvement toward better reliability.

The Precast/Prestressed Concrete Institute (PCI) is the technical institute for precast/prestressed concrete industry. The plant involves activities such as placing high tensile steel strings inside the concrete products before they harden. This process needs the strings to be "stressed" hydraulically with high tension, which provides possibility of breaking the strand. Hence, employees may face a severe injury around the stressing bed. As various activities take place on the plant at the same time, employees must follow certain safety protocols while being around the plant. Another safety concern on the precast plant is silica exposure. Occupational Safety and Health Administration (OSHA) has provided various guidelines and tools to minimize silica exposure. Employees need to be careful and follow these safety protocols, otherwise it may lead to severe lung disease. Thus, employees need the appropriate safety training which will motivate them to follow safety protocols rigorously. The Bayesian Network (BN) methodology helps analyze plant structure to understand potential risk factors and causes that can be fixed by the employer paying more attention. The current traditional training methods such as videos, PowerPoint slides, or on-paper training, are not as effective in conveying the severity of the risky situations. This research focuses on precast plant activities while trying to identify the factors affecting plant safety. The current results suggest that using the BN study for the factors, such as stressing, chipping, leg injuries, tripping, and suspended loads, that may cause accidents or affect plant safety have a major impact on overall plant safety. Further sections of the dissertation discuss Fault Tree Analysis for risk assessment. It is observed that the BN study outperforms the risk assessment. Improvisation in safety protocols associated with these factors will help mitigate overall plant risks. In addition, study includes the development of immersive training methods and comparison of the immersive method to current safety training methods. Virtual Reality (VR) training module provides significant evidence to improvement in motivation level compared to traditional training. Knowledge gain concerning the safety protocols proves to be increasing for employees after the VR training method compared to the traditional training methods.

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