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This research has first reviewed the current status and future aspects of marine and offshore safety assessment. The major problems identified in marine and offshore safety assessment in this research are associated with inappropriate treatment of uncertainty in data and human error issues during the modelling process. Following the identification of the research needs, this thesis has developed several analytical models for the safety assessment of marine and offshore systems/units. Such models can be effectively integrated into a risk-based framework using the marine formal safety assessment and offshore safety case concepts. Bayesian network (BN) and fuzzy logic (FL) approaches applicable to marine and offshore safety assessment have been proposed for systematically and effectively addressing uncertainty due to randomness and vagueness in data respectively. BN test cases for both a ship evacuation process and a collision scenario between the shuttle tanker and Floating, Production, Storage and Offloading unit (FPSO) have been produced within a cause-effect domain in which Bayes' theorem is the focal mechanism of inference processing. The proposed FL model incorporating fuzzy set theory and an evidential reasoning synthesis has been demonstrated on the FPSO-shuttle tanker collision scenario. The FL and BN models have been combined via mass assignment theory into a fuzzy-Bayesian network (FBN) in which the advantages of both are incorporated. This FBN model has then been demonstrated by addressing human error issues in a ship evacuation study using performance-shaping factors. It is concluded that the developed FL, BN and FBN models provide a flexible and transparent way of improving safety knowledge, assessments and practices in the marine and offshore applications. The outcomes have the potential to facilitate the decision-making process in a risk-based framework. Finally, the results of the research are summarised and areas where further research is required to improve the developed methodologies are outlined.

This research has reviewed the current status of offshore and marine safety. The major problems identified in the research are associated with risk modelling under circumstances where the lack of data or high level of uncertainty exists. This PhD research adopts an object-oriented approach, a natural and straightforward mechanism of organising information of the real world systems, to represent the Offshore Gas Supply Systems (OGSSs) at both the component and system levels. Then based on the object-oriented approach, frameworks of aggregative risk assessment and fault tree analysis are developed. Aggregative risk assessment is to evaluate the risk levels of components, subsystems, and the overall OGSS. Fault trees are then used to represent the cause-effect relationships for a specific risk in the system. Use of these two assessment frameworks can help decision makers to obtain comprehensive view of risks in the OGSS. In order to quantitatively evaluate the framework of aggregative risk, this thesis uses a fuzzy aggregative risk assessment method to determine the risk levels associated with components, subsystems, and the overall OGSS. The fuzzy aggregative risk assessment method is tailored to quantify the risk levels of components, subsystems, and the OGSS. The proposed method is able to identify the most critical subsystem in the OGSS. As soon as, the most critical subsystem is identified, Fuzzy Fault Tree Analysis (FFTA) is employed to quantitatively evaluate the cause-effect relationships for specific undesired event. These results can help risk analysts to select Risk Control Options (RCOs) for mitigating risks in an OGSS. It is not financially possible to employ all the selected RCOs. Therefore, it is necessary to rank and select the best RCO. A decision making method using the Fuzzy TOPSIS (FTOPSIS) is proposed to demonstrate the selection of the best RCOs to control the existing risks in the system. The developed models and frameworks can be integrated to formulate a platform which enables to facilitate risk assessment and safety management of OGSSs without jeopardising the efficiency of OGSSs operations in various situations where traditional risk assessment and safety management techniques cannot be effectively applied.

This research is carried out to improve Human Reliability Analysis (HRA) in oil tanker operations in general, to extend and enhance in specific Cognitive Reliability and Error Analysis Method (CREAM), with the aim of reducing human error and thus subsequently preventing oil tanker spills. It is concentrated on oil tanker operations to address the limitation of availability of human reliability data in the maritime domain. The continual occurrence of oil tanker spills, which was substantiated with analysis of historical data of oil tanker incidents/accidents from 1970 to 2008, provides a judicious reason to conduct this research. The critical review of Formal Safety Assessment (FSA) and HRA results in the development of a conceptual framework of HRA facilitating FSA and incorporating Human Organisational Factors (HOF), which addresses the shortcomings of the generic HRA and FSA methodologies that exist independently in the management of oil tankers to prevent oil spills. The CREAM is reviewed due to its prominent use in identifying the root causes of human error. However, its inability of providing solutions to an incident/accident investigation and robust quantification of human reliability features stimulates the development of an advanced CREAM and a human reliability quantification model using a combined Analytic Hierarchical Process (AHP) and fuzzy logic approach in this research. In addition to facilitating identification of the root causes of human error, the advanced CREAM also provides the solutions to a quantification model, which enables the development of HRA data in the maritime domain. Furthermore, lack of CREAM studies on relationships among Common Performance Conditions (CPCs) is addressed by proposing a Decision Making Trial and Evaluation Laboratory (DEMATEL) model, which allows for a comprehensive understanding of relationships and interdependencies among the CPCs. The model could also be used toappreciate and assimilate the relationships and interdependencies among human factor variables involved in other transportation systems and industrial fields. Finally, the research is concluded with an integrated AHP and fuzzy Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) model for determining the selection of an appropriate risk control option (RCO) while performing an incident/accident investigation by taking subjective judgments of decision makers into consideration. This research as a pioneer work in developing and applying advanced techniques to improve the generic CREAM in oil tanker operations establishes a foundation for future effort to improve the use of CREAM in other industries. The techniques developed can also be tailored to investigate and deal with an incident/accident effectively, resulting in the reduction of human error within the system management of any organisation.

No description available.

Introdução: A incidência do melanoma cutâneo (MC) está crescendo mais rapidamente que a de qualquer outro câncer. Devido ao seu potencial para metástases e à falta de terapias efetivas para a maioria dos pacientes em estágio avançado, o diagnóstico precoce do MC é crucial. Alguns dos fatores prognósticos mais importantes no MC são a espessura de Breslow e a presença de metástase linfonodal. O Tecnécio-99m-sestamibi (MIBI) é um radiofármaco usado rotineiramente em cintilografias miocárdicas e tem conhecidas propriedades para detecção de tumores malignos, incluindo câncer de mama, tumores cerebrais e melanomas primários e metastáticos. Objetivo: Avaliar a correlação entre a espessura de Breslow e a intensidade da captação de MIBI (IC-MIBI) em lesões primárias de MC. Métodos: Foram selecionados pacientes com lesões clinica e dermatoscopicamente suspeitas de MC. Os pacientes receberam uma injeção intravenosa de 740 – 1110 MBq (20 mCi) de MIBI. Após 10 minutos, o equipamento gamma-probe foi usado para detectar a IC-MIBI na lesão cutânea e em 2 pontos equidistantes na pele normal. A razão entre as contagens radioativas na lesão e a média da pele normal foi considerada a IC-MIBI. A seguir, pacientes realizaram SPECT (Single Photon Emission Computed Tomography) do local da lesão e da região linfonodal correspondente. Exérese da lesão cutânea e exame anatomopatológico foram então realizados. Pacientes portadores de lesões com Breslow > 1 mm ou < 1mm com ulceração/regressão espontânea realizaram biópsia do linfonodo sentinela. Resultados: Dezesseis pacientes com 20 lesões foram estudados (8 homens, 8 mulheres, de 34 – 81 anos, média 61 anos). Quatorze lesões eram melanomas e 6 eram nevos melanocíticos (NM). Cinco lesões eram melanomas in situ. A média da espessura de Breslow foi de 0,45 mm (variação: 0,30 – 14,90 mm). A média da IC-MIBI foi 1,54 (±0.58) contagens radioativas nos MC e 1,04 (±0.10) nos NM (P = 0.007). Houve forte correlação positiva entre a IC-MIBI e a espessura de Breslow (rs = 0.74, P= 0.003). Analisando as lesões em categorias de Breslow, houve diferença estatisticamente significativa (P < 0.001) entre as lesões com Breslow < 1mm (IC-MIBI = 1.23 ± 0.28 contagens radioativas) e Breslow > 1 mm (IC-MIBI = 2.32 ± 0.32 contagens radioativas). Nenhum dos NM apareceu nas imagens de SPECT. Dos MC, 4 lesões, que apresentavam Breslow > 1mm, apareceram nas imagens de SPECT. Conclusão: Neste estudo, embora tenha demonstrado uma diferença significativa entre melanomas finos (< 1mm) e espessos (> 1mm), a IC-MIBI no local da lesão não foi diferente entre NM e melanomas finos ou in situ. Por isso, MIBI parece ser útil principalmente em melanomas espessos, o que também foi confirmado pela positividade do SPECT apenas nestes casos. Entretanto, a possibilidade de correlacionar a IC-MIBI com categorias de Breslow pode facilitar os procedimentos cirúrgicos, permitindo a remoção de melanomas com margens cirúrgicas adequadas e a realização ou não de biópsia de linfonodo sentinela em um mesmo momento cirúrgico, reduzindo morbidade e custos. / Introduction: Given its propensity to metastasize, and lack of effective therapies for most patients with advanced disease, early detection of melanoma is a clinical imperative. The most important prognostic factors are Breslow thickness and nodal metastases. Technetium-99m-sestamibi (MIBI) is a radiopharmaceutical used routinely for cardiologic scintigraphy and has also well-known tumor-seeking properties. It has been used successfully to detect various tumors, including breast cancer, brain tumors, and primary and metastatic melanoma. Objetive: This study has been designed in order to evaluate the correlation between Breslow thickness and MIBI uptake by primary CM lesions. Methods: Patients were recruited by a dermatologist on the grounds of a clinically and dermoscopically suspicious melanocytic lesion. Patients received intravenous injection of 740 – 1110 MBq (20 mCi) of MIBI. After 10 minutes, gamma-probe was used to detect the intensity of MIBI uptake by the cutaneous lesion and at two equidistant points on normal skin. The ratio number of radioactive counts at cutaneous lesion / mean of radioactive counts at normal skin was considered to determinate the MIBI uptake intensity (MIBI-UI). Then, SPECT imaging of the lesion site and respective lymph node region was obtained. After scintigraphy, exeresis of the cutaneous lesion and histological analysis were performed. Lesions with Breslow thickness > 1 mm or < 1 mm with ulceration/spontaneous regression underwent sentinel lymph node biopsy. Results: Sixteen patients with 20 lesions were investigated (8 males, 8 females, age range 34 – 81 years, mean 61 years). Fourteen lesions were CM and 6 were melanocytic nevi (MN). Five lesions were melanoma in situ. Breslow thickness median was 0.45 mm (range 0.30 - 14,9 mm). The mean MIBI-UI was 1.54 (±0.58) radioactive counts in CM and 1.04 (±0.10) radioactive counts in MN (P = 0.007). There was strong positive correlation between MIBI-UI and Breslow thickness (rs = 0.74, P= 0.003). Grouping the lesions on Breslow categories, there was a statistically significant difference (P < 0.001) between lesions with Breslow thickness < 1 mm (MIBI-UI = 1.23 ± 0.28 radioactive counts) and Breslow thickness > 1 mm (MIBI-UI = 2.32 ± 0.32 radioactive counts). None of the MN appeared at SPECT images. Of melanomas, 4 (28,6%) were SPECT positive at cutaneous site. All those were Breslow thickness > 1 mm. Conclusion: On this study, although there is a significant difference between thin (< 1 mm) and thick (> 1 mm) melanomas, MIBI intensity at the lesion site is not different between benign nevus and in situ or thin melanomas. Then, MIBI seems to be useful mainly in thick melanomas, as also confirmed by the positivity of the SPECT image only in these cases. However, the possibility of correlating MIBI uptake intensity with Breslow categories may facilitate surgical procedures, allowing to remove melanomas with appropriated surgical margins and to perform or not sentinel lymph node biopsy in the same surgical time, reducing morbidity and cost.

Introdução: A incidência do melanoma cutâneo (MC) está crescendo mais rapidamente que a de qualquer outro câncer. Devido ao seu potencial para metástases e à falta de terapias efetivas para a maioria dos pacientes em estágio avançado, o diagnóstico precoce do MC é crucial. Alguns dos fatores prognósticos mais importantes no MC são a espessura de Breslow e a presença de metástase linfonodal. O Tecnécio-99m-sestamibi (MIBI) é um radiofármaco usado rotineiramente em cintilografias miocárdicas e tem conhecidas propriedades para detecção de tumores malignos, incluindo câncer de mama, tumores cerebrais e melanomas primários e metastáticos. Objetivo: Avaliar a correlação entre a espessura de Breslow e a intensidade da captação de MIBI (IC-MIBI) em lesões primárias de MC. Métodos: Foram selecionados pacientes com lesões clinica e dermatoscopicamente suspeitas de MC. Os pacientes receberam uma injeção intravenosa de 740 – 1110 MBq (20 mCi) de MIBI. Após 10 minutos, o equipamento gamma-probe foi usado para detectar a IC-MIBI na lesão cutânea e em 2 pontos equidistantes na pele normal. A razão entre as contagens radioativas na lesão e a média da pele normal foi considerada a IC-MIBI. A seguir, pacientes realizaram SPECT (Single Photon Emission Computed Tomography) do local da lesão e da região linfonodal correspondente. Exérese da lesão cutânea e exame anatomopatológico foram então realizados. Pacientes portadores de lesões com Breslow > 1 mm ou < 1mm com ulceração/regressão espontânea realizaram biópsia do linfonodo sentinela. Resultados: Dezesseis pacientes com 20 lesões foram estudados (8 homens, 8 mulheres, de 34 – 81 anos, média 61 anos). Quatorze lesões eram melanomas e 6 eram nevos melanocíticos (NM). Cinco lesões eram melanomas in situ. A média da espessura de Breslow foi de 0,45 mm (variação: 0,30 – 14,90 mm). A média da IC-MIBI foi 1,54 (±0.58) contagens radioativas nos MC e 1,04 (±0.10) nos NM (P = 0.007). Houve forte correlação positiva entre a IC-MIBI e a espessura de Breslow (rs = 0.74, P= 0.003). Analisando as lesões em categorias de Breslow, houve diferença estatisticamente significativa (P < 0.001) entre as lesões com Breslow < 1mm (IC-MIBI = 1.23 ± 0.28 contagens radioativas) e Breslow > 1 mm (IC-MIBI = 2.32 ± 0.32 contagens radioativas). Nenhum dos NM apareceu nas imagens de SPECT. Dos MC, 4 lesões, que apresentavam Breslow > 1mm, apareceram nas imagens de SPECT. Conclusão: Neste estudo, embora tenha demonstrado uma diferença significativa entre melanomas finos (< 1mm) e espessos (> 1mm), a IC-MIBI no local da lesão não foi diferente entre NM e melanomas finos ou in situ. Por isso, MIBI parece ser útil principalmente em melanomas espessos, o que também foi confirmado pela positividade do SPECT apenas nestes casos. Entretanto, a possibilidade de correlacionar a IC-MIBI com categorias de Breslow pode facilitar os procedimentos cirúrgicos, permitindo a remoção de melanomas com margens cirúrgicas adequadas e a realização ou não de biópsia de linfonodo sentinela em um mesmo momento cirúrgico, reduzindo morbidade e custos. / Introduction: Given its propensity to metastasize, and lack of effective therapies for most patients with advanced disease, early detection of melanoma is a clinical imperative. The most important prognostic factors are Breslow thickness and nodal metastases. Technetium-99m-sestamibi (MIBI) is a radiopharmaceutical used routinely for cardiologic scintigraphy and has also well-known tumor-seeking properties. It has been used successfully to detect various tumors, including breast cancer, brain tumors, and primary and metastatic melanoma. Objetive: This study has been designed in order to evaluate the correlation between Breslow thickness and MIBI uptake by primary CM lesions. Methods: Patients were recruited by a dermatologist on the grounds of a clinically and dermoscopically suspicious melanocytic lesion. Patients received intravenous injection of 740 – 1110 MBq (20 mCi) of MIBI. After 10 minutes, gamma-probe was used to detect the intensity of MIBI uptake by the cutaneous lesion and at two equidistant points on normal skin. The ratio number of radioactive counts at cutaneous lesion / mean of radioactive counts at normal skin was considered to determinate the MIBI uptake intensity (MIBI-UI). Then, SPECT imaging of the lesion site and respective lymph node region was obtained. After scintigraphy, exeresis of the cutaneous lesion and histological analysis were performed. Lesions with Breslow thickness > 1 mm or < 1 mm with ulceration/spontaneous regression underwent sentinel lymph node biopsy. Results: Sixteen patients with 20 lesions were investigated (8 males, 8 females, age range 34 – 81 years, mean 61 years). Fourteen lesions were CM and 6 were melanocytic nevi (MN). Five lesions were melanoma in situ. Breslow thickness median was 0.45 mm (range 0.30 - 14,9 mm). The mean MIBI-UI was 1.54 (±0.58) radioactive counts in CM and 1.04 (±0.10) radioactive counts in MN (P = 0.007). There was strong positive correlation between MIBI-UI and Breslow thickness (rs = 0.74, P= 0.003). Grouping the lesions on Breslow categories, there was a statistically significant difference (P < 0.001) between lesions with Breslow thickness < 1 mm (MIBI-UI = 1.23 ± 0.28 radioactive counts) and Breslow thickness > 1 mm (MIBI-UI = 2.32 ± 0.32 radioactive counts). None of the MN appeared at SPECT images. Of melanomas, 4 (28,6%) were SPECT positive at cutaneous site. All those were Breslow thickness > 1 mm. Conclusion: On this study, although there is a significant difference between thin (< 1 mm) and thick (> 1 mm) melanomas, MIBI intensity at the lesion site is not different between benign nevus and in situ or thin melanomas. Then, MIBI seems to be useful mainly in thick melanomas, as also confirmed by the positivity of the SPECT image only in these cases. However, the possibility of correlating MIBI uptake intensity with Breslow categories may facilitate surgical procedures, allowing to remove melanomas with appropriated surgical margins and to perform or not sentinel lymph node biopsy in the same surgical time, reducing morbidity and cost.

Measurement of the volumetric flow rate of each of the flowing components in multiphase flow is often required and this is particularly true in Production Logging applications. Thus, an increasing level of interest has been shown in making flow rate measurements in multiphase flow. A new generation of tomographic instrument, which enables measurement of the instantaneous local velocity vector and the instantaneous local volume fraction of the dispersed phase, is now being introduced. However validation and calibration of such instruments is necessary. This thesis describes the development of a miniaturised local four-sensor conductivity probe capable of acquiring measurements of the local velocity vector, gas volume fraction and the local axial gas velocity in the bubbly gas-liquid flows. Experimental techniques in which the probe was used to obtain the local gas velocity vector and the local gas volume fraction in a bubbly gas-liquid flow are also described. High speed cameras are introduced for the measurement of the reference velocity of the bubbles. The camera images are also used to plot the trajectory of any bubble that hits all four-sensor of the probe. Extensive experimental results showing the distribution of the local gas volume fraction and the local axial, azimuthal and the radial bubble velocity components in vertical and swirling gas-liquid flows are presented.

The governments of Scotland and England have responded to the increase in flood risk by introducing legislation intended to manage present day flood risk and to avoid future flood risk. This thesis evaluates how the new policy regime has evolved and been implemented in Scotland and England, focusing particularly in Local Authorities, and using contrasts in rural and urban settings to reveal how the policy has had to be adapted to apply effectively in these different physical and administrative environments. Based on discourse theory and the institutionalisation features of policy networks, it is argued first that the new policy regime is subject to multiple interpretations and, second that policy change occurs as a result of the transformation of institutional practices of the multiple flood governance discourses by policy narratives in the policy process. The concept of the advocacy coalition framework is applied to reveal how contrasting local governance approaches result from continuous interactions between national policies and distinctive, local factors. These arguments are supported by the results of empirical research that examined policy change and local governance interpretation through textual analysis of relevant policy documents, interviews with key institutional stakeholders and participant observation of a local stakeholder meeting. Research findings reveal how the more pro-active local governance approaches serve as innovators in informing future national policies. This process stems from local interpretation of existing national policy through the mediating effects of distinctive local policy factors that result in the introduction of new policy ideas and actors. These ideas and the involvement of new actors are in turn transferred through revisions to national policies of flood risk governance. Consequently the policy mediating features of Local Authorities are manifest through first, the utility of policy narratives in driving national policy change and second, in shaping policies in local governance approaches.