Autonomous vehicles (AVs) are a class of safety-critical systems that are capable of decision-making and operate with little or no human intervention. For such complex systems designed to function in diverse operational domains such as rain, snow, freeway, urban roads, etc., system safety is paramount. Management of the system's safety throughout its life-cycle, from the conceptualization stage to the end of the lifecycle, is of primary importance. We describe a revision of functional safety standard ISO 26262 to support autonomous vehicles and the underlying electronic/electrical control architecture. There is a need to modify the Automotive Safety Integrity Levels (ASILs) defined in the ISO 26262 as "Controllability", a factor in determining an ASIL, is no longer applicable; the driver is no longer in a position to control the vehicle. The vehicle has taken over the responsibility of evaluating the environment and determines its next course of action to complete its current mission. These decisions have a tremendous impact on the overall safety of the system during a hazardous event and can be the difference between a successful journey and a traffic incident. To better enable the designers of such systems, we introduce a new method to assess the functional safety and derive safety goals, which are the top level safety requirement. We present a new metric-Risk Mitigation Factor to assess the decision making capability of the vehicle and to replace controllability in the ASIL definition. The case study presented highlights the advantages of using the introduced metric in defining safety goals for the autonomous vehicle. / Master of Science / Autonomous vehicles (AVs) are changing the way we perceive mobility and transportation. AVs are soon to be a part of everyday life, from giving you a ride to the office to taking children to the dentist. All the possible benefits of AVs are attainable if the systems designed are safe for use. Safety in AVs is the primary challenge in design and development. It is crucial to incorporate the principles of safety in system design from the beginning of the inception phase to the end of the lifecycle of the vehicle. The challenges for ensuring safety in AVs are enormous, from implementing the correct operation for a system to assuring that system behavior is safe in the presence of a malfunction; the scale and complexity of the systems drive the safety requirements. In the work presented, we focus on the functional safety of the underlying electrical/ electronic architecture of the vehicle, describing a revision of the automotive functional safety standard ISO 26262 for AV development. We propose to leverage the decision-making capabilities of the vehicle to assure safety in a hazardous situation.

Thesis (MBA (Business Management))--University of Stellenbosch, 2009.

C'est dans le contexte délicat du milieu marin, marqué par l'écroulement des stockshalieutiques et la conservation urgente des espèces de prédateurs marins, que s'inscrit cette étude sur la déprédation (i.e. prélèvement des poissons capturés) par les orques et les cachalots sur la pêche à lapalangre dans la ZEE de l'Archipel de Crozet.Le premier objectif a été d'évaluer les conséquences socio-économiques du phénomène. Entre 2003 et2010 les orques ont interagi avec un total de 43,3% des palangres relevées et les cachalots avec 57,5%,les deux espèces étant présentes simultanément sur 27.8% des palangres (n=5438). Les orques, seulesou associées aux cachalots ont été estimées prélever 926 ± 76 tonnes de légines sur l'ensemble de lapériode, représentant un taux de déprédation de 17,7%.Trois facteurs opérationnels ont été identifiés comme faisant varier la déprédation par les orques : i)utilisation de palangres courtes (<5000m) en absence d'orques, ii) déplacement du navire sur desdistances supérieures à 40nq pour quitter une zone confrontée à la déprédation et changer de zone, iii)utilisation de vitesse de remontée des hameçons à bord supérieures à 50 H.min-1.Le deuxième objectif de cette étude a été d'évaluer les conséquences démographiques de ladéprédation sur la population d'orques de Crozet. Le suivi à long terme des individus a permis demettre en évidence des réponses différentielles des unités sociales en fonction de leur degréd'interaction avec les pêcheries. / Over the last 50 years, fisheries have undergone a major decline worldwide. With an increasedcompetition for resource, depredation (i.e. removal of catches on fishing gear) has recently become amajor case of conflict between humans and marine predators. In this study I focused on thedepredation on Patagonian toothfish fisheries by killer and sperm whales in the Crozet EEZ. The firstpart of the study aimed at assessing the socio-economic consequences of this issue. Killer and spermwhales have interacted with 43.3% and 57.5% of longlines (n=6751) respectively from 2003 to 2010.Killer whales, alone or co-occurring with sperm whales were responsible for an estimated loss of 926± 76 tons of toothfish over that period, which represents 17.7% of the total catch.Three operational factors were identified as influencing significantly depredation levels: i) the use ofshort longlines (<5000m) in absence of killer whales, ii) the displacement of vessels on distances>40nq to leave the whales behind and iii) the use of longline hauling speed > 50 H.min-1.The second aim of the study was to investigate the consequences of depredation on the Crozet killerwhale population. The long term monitoring of individuals showed divergent demographic trajectoriesrelated to the depredation level of matrilines. During the 1990s, matrilines interacting with fisherieshave undergone a high mortality due to lethal interactions with illegal fishing vessels using explosivesto repel the whales.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. 10 February, 2017. / Climate change due to the ever-increasing emission of anthropogenic greenhouse gases arising from the use of fossil fuels for power generation and most industrial processes is now a global challenge. It is therefore imperative to develop strategies or modern technologies that could mitigate the effect of global warming due to the emission of CO2. Carbon capture and storage (CCS) is a viable option that could ensure the sustainable use of cheap fossil fuels for energy generation with less CO2 emission. Amongst existing CCS technologies, absorption technology using monoethanolamine (MEA) is very mature and widely embraced globally. However, the absorption technology has a lot of challenges such as, low CO2 loading, high energy requirement for solvent regeneration, corrosive nature etc. On this note, the adsorption technology using solid sorbents is being considered for CO2 capture due to its competitive advantages such as flexibility, low energy requirement for sorbent regeneration, non-corrosive nature etc. On the other hand, adsorbents have a very vital role to play in adsorption technology and there is need to understand the behaviour of adsorbents for CO2 capture under different operating conditions in order to adapt them for wider applications. On this note, the study contained in this dissertation investigated the adsorption behaviour of a novel polymer-based adsorbent (polyaspartamide) during post-combustion CO2 capture using experimental study and mathematical modelling approach. Polyaspartamide is an amine-rich polymer widely used in drug delivery. In addition, its rich amine content increases its affinity for CO2. Its porosity, thermal stability and large surface area make it a promising material for CO2 capture. In view of this, polyaspartamide was used as the adsorbent for post-combustion CO2 capture in this study. This dissertation investigated the kinetic behaviour, the diffusion mechanism and rate limiting steps (mass transfer limitation) controlling the CO2 adsorption behaviour of this adsorbent. Furthermore, effect of impurities such as moisture and other operating variables such as temperature, pressure, inlet gas flow rate etc. on the CO2 adsorption behaviour of polyaspartamide was also investigated. Existing mathematical models were used to understand the kinetics and diffusion limitation of this adsorbent during CO2 capture. Popularly used gas-solid adsorption models namely; Bohart- Adams and Thomas model were applied in describing the breakthrough curves in order to ascertain the equilibrium concentration and breakthrough time for CO2 to be adsorbed onto polyaspartamide. Lagergren’s pseudo 1st and 2nd order models as well as the Avrami kinetic models were used to describe the kinetic behaviour of polyaspartamide during post-combustion CO2 capture. Parameter estimations needed for the design and optimization of a CO2 adsorption system using polyaspartamide were obtained and presented in this study. The Boyd’s film diffusion model comprising of the interparticle and intra-particle diffusion models were used to investigate the effect of mass transfer limitations during the adsorption of CO2 onto polyaspartamide. Data obtained from continuous CO2 adsorption experiments were used to validate the models in this study. The experiments were conducted using a laboratory-sized packed-bed adsorption column at isothermal conditions. The packed bed was attached to an ABB CO2 analyser (model: ABB-AO2020) where concentrations of CO2 at various operating conditions were obtained. The results obtained in this study show that temperature, pressure and gas flow rate had an effect on the adsorption behaviour of polyaspartamide (PAA) during CO2 capture. Polyaspartamide exhibited a CO2 capture efficiency of 97.62 % at the lowest temperature of 303 K and pressure of 2 bar. The amount of CO2 adsorbed on polyaspartamide increased as the operating pressure increased and a decrease in the adsorption temperature resulted in increased amount of CO2 adsorbed by polyaspartamide. The amounts of CO2 adsorbed on polyaspartamide were 5.9, 4.8 and 4.1 mol CO2/kg adsorbent for adsorption temperatures of 303, 318 and 333 K, respectively. The maximum amount of CO2 adsorbed by polyaspartamide at different flow rates of 1.0, 1.5 and 2.5 ml/s of the feed gas were 7.84, 6.5 and 5.9 mmol CO2/g of adsorbent. This shows that higher flow rates resulted in decreased amount of CO2 adsorbed by polyaspartamide because of low residence time which eventually resulted in poor mass transfer between the adsorbent and adsorbate. Under dry conditions, the adsorption capacity of polyaspartamide was 365.4 mg CO2/g adsorbent and 354.1 mgCO2/g adsorbent under wet conditions. Therefore, the presence of moisture had a negligible effect on the adsorption behaviour of polyaspartamide. This is very common with most amine-rich polymer-based adsorbents. This could be attributed to the fact that CO2 reacts with moisture to form carbonic acid, thereby enhancing the CO2 adsorption capacity of the material. In conclusion, this study confirmed that the adsorption of CO2 onto polyaspartamide is favoured at low temperatures and high operating pressures. The adsorption of CO2 onto polyaspartamide was governed by film diffusion according to the outcome of the Boyd’s film diffusion model. It was also confirmed that intra-particle diffusion was the rate-limiting step controlling the adsorption of CO2 onto polyaspartamide. According to the results from the kinetic study, it can be inferred that lower temperatures had an incremental effect on the kinetic behaviour of polyaspartamide, external mass transfer governed the CO2 adsorption process and the adsorption of CO2 onto polyaspartamide was confirmed to be a physicochemical process (both physisorption and chemisorption). / MT2017

Afin de rendre les piles à combustible à membrane échangeuse de protons viables économiquement dans le domaine automobile, des problèmes de durabilité et de coût sont à résoudre. La compréhension et le contrôle des dégradations à l'intérieur de la cellule et surtout de l'AME sont toujours le centre d’intérêt de nombreux laboratoires mais aussi d'industriels. Les milliers d'arrêt-démarrages subis par la pile provoquent une importante corrosion du support carbone. Le platine utilisé étant un catalyseur onéreux, la modélisation numérique permet l'analyse de phénomènes à moindre coût.Dans ces travaux, deux modèles ont été développés afin de modéliser les phases transitoires que sont les arrêt-démarrages. Tout d'abord, une étude sur les performances de la pile a été effectuée en utilisant le modèle. Le couplage entre les modèles le long du canal et dent/canal est introduit. Ensuite, une analyse des phénomènes se déroulant durant les arrêt-démarrages est effectuée. Des phases temporelles sont proposées afin de découper ces différents phénomènes. Le mécanisme des courants inverses (durant lequel la corrosion du carbone apparaît) est minutieusement détaillé avec l'aide du modèle. L'accent est porté sur les hétérogéneités de dégradations apparaissant entre l'entrée et la sortie mais aussi entre le canal et la dent. Enfin, le modèle est utilisé afin de simuler et proposer des stratégies de mitigations. Les tendances attendues par la littérature sont confirmées mais aussi évaluées. Parmi les idées suggerées, l'optimisation du design dent/canal tout au long du canal est proposée afin de limiter les dégradations. / In order to make Proton Exchange Membrane Fuel Cells economically viable for an automotive application, durability and cost problems have to be addressed. Understanding and mitigating degradations inside the cell especially in the MEA are still the focus of several laboratories and also industrials. The several thousands startups and shutdowns that the fuel cell underwent induce severe corrosion of the carbon support. As the catalyst used is expensive, namely platinum, modeling is a great asset to comprehend and analyze this phenomenon costwise.In this work, two models were developed for modeling the transient phases that are the startup and shutdown. First a performance study is presented to validate the use of the model and to introduce the coupling between the along the channel model and the rib/channel model. Then an analysis of the phenomena occurring during the startup (and shutdown) is carried out. Phases are suggested to break down the different phenomena. The reverse-current decay mechanism, when carbon corrosion occurs, is thoroughly detailed using the model. Degradation heterogeneities are highlighted whether they are between inlet and outlet or rib and channel. Finally the model is used to emulate and suggest mitigation strategies. Degradation trends are confirmed and evaluated. New ideas like an original flow field design are tested to mitigate degradation.

城市化是影響全球碳循環的最重要的由人類活動主導的影響因素之一。本質上，城市碳儲存和碳釋放，無論以人工的（如能源消耗、建築物、廢物等）或自然組成部份（如城市綠色植被，城市土壤等），都與城市緊密相關。在城市碳循環中，無論人工或自然組成部份都是同等重要，因為在研究中必須同時考慮兩者的貢獻。然而，已有的研究過於片面，且大多數集中于城市能源利用和碳排放方面。該研究試圖將城市系統作為一個整體，定量地探討城市人工及自然組成部份對二氧化碳排放量的貢獻。 / 首先，我們提出一個基於過程的“城市土地的定義，以表述城市土地動態變化的本質，并運用閾值方法成功提取所定義的“城市土地。我們運用多源的遙感數據，包括夜晚燈光影像，LandSat影像及Modis影像，分析城市化過程及相應的土地利用/覆蓋變化。總體而言，在過去25年間，中國城市用地擴張了3.8倍，農田和林地是城市土地擴張的主要來源。 / 其次，以經過校準的夜晚燈光數據作為指示變量，我們開發了一個自上而下的分解模型來估算城市尺度下化石燃料消耗導致的二氧化碳排放。在中國快速城市化的背景下，城市二氧化碳排放量占全國總排放量的比例大幅增加。與農村地區相比，由於較高的收入水平，生活方式的改變及更便利地獲得電力能源，中國城市的人均排放量遠高於全國平均量。這與發達國家的情景截然相反。另外，由於當地經濟規模和結構的影響，東部地區的人均碳排放量低於西部地區。結果還表明，快速增長的經濟和城市化是二氧化碳排放量增加的主要驅動力，且能源效率在2000年之後反而呈現增長趋势，也是促進二氧化碳排放量增加的主要原因。如果國家宣佈并嚴格執行更嚴格的可持續發展目標，則經濟結構及能源結構調整將在減碳方面發揮作用。 / 第三，本研究還根據儲存-變化方法，估算了城市系統的自然組成部份，也就是城市植被和土壤的碳儲存和釋放。結果表明，儲存於城市植被和土壤中碳量與城市化石燃料排放的碳量相當，且城市土壤是主要的碳庫，儲存了約93%的碳。隨著城市不斷擴張，由於大量自然植被被破壞，城市植被變成碳源并向大氣釋放碳；而城市土壤則變成碳庫，吸收了大氣中部份的二氧化碳。鑒於中國未來持續的城市化過程，該研究結果為城市管理者提供了科學依據，以通過提高城市植被和土壤的碳儲量，吸收部份化石燃料燃燒排放的二氧化碳。 / 最後，我們還運用格蘭傑檢驗分析小尺度氣候變量對二氧化碳增加的響應。結果表明，在中國城市化較低地區，氣溫與二氧化碳變化存在雙向格蘭傑因果關係；而在快速城市化地區，如東部沿海城市，僅存在氣溫變化導致二氧化碳排放量增加的單向格蘭傑因果關係。該研究首次在城市尺度解釋了氣候對二氧化碳增量的響應關係。總體而言，本論文綜合地探索了中國快速城市化背景下，城市人工及自然組成部份對二氧化碳排放量的共同貢獻。這些研究結果為當地政府建設低碳城市提供了科學依據和決策支持。 / Urbanization is undoubtedly one of the most significant anthropogenic forces affecting global carbon cycle. Carbon storage and release through anthropogenic (e.g. energy consumption, building, waste) and natural components (e.g. urban vegetation and soil) are intrinsically coupled in urban areas. Both anthropogenic and natural components are equally important for understanding the carbon cycle in urban areas and have to be considered simultaneously. Present studies however mostly one-sided and primarily focus on anthropogenic emissions. Given the substantial scientific gaps, this study aims to build better knowledge on the contributions of urban areas to the increasing atmosphere CO₂ emissions at an urban scale, considering both anthropogenic and natural components simultaneously. / First, a process-based definition of urban areas is proposed to capture the inherent dynamics of urban areas, and a threshold technique is developed to map the defined urban areas in this study. Multi-sensor remotely sensed data are used to analyze the dynamic urbanization and related land use/cover conversions. Overall, urban areas have increased by 3.8 times over the studied period of 1985-2010. Croplands and forests are the major sources of the growing urban areas. / Second, taking calibrated nighttime light imagery as a proxy variable, we develop a top-down model to estimate fossil fuel CO₂ emissions on the urban scale. Driven by the rapid urbanization in China, the contributions of urban areas to the CO₂ emissions have increased substantially. In contrast to the developed counties, per capita CO₂ emissions in urban China are higher than the national average, due to higher income, change in lifestyle and easy access to electricity, whereas per capita CO₂ emissions in eastern China is lower than that in western China, due to the diverse scale and structure of local economy. Our analysis also reveals that the booming economy and urbanization are major drivers of the increasing fossil fuel CO₂ emissions, while the decoupling effect of energy efficiency reverses in the post-2000 period caused by the booming economy. It is foreseeable that economic reconstruction and energy structure would play a significant impact on carbon reduction if stricter environmental targets are released. / Third, carbon storage and change in natural components of urban areas, in particular, urban vegetation and soils, are also estimated in this study. A stock-change method is applied in this study. This study identifies that the amount of carbon storage in urban areas is comparable to that emitted from fossil fuel burning, and urban soils are the major carbon pools in urban areas. Along with urban expansions, urban vegetation becomes sources of carbon due to loss of biomass, whereas urban soils act as sinks of carbon because increasing urban areas enhance the carbon storage in them. Given the foreseeable urbanization in China, our study has implications for urban managers to enhance carbon storage through urban vegetation and soils, hence offsetting CO₂ emissions from fossil fuel burning. / Finally, a local temperature response to the increasing CO₂ in urban areas is analyzed by local Granger causality test. Bidirectional Granger causality presents between surface air temperature and carbon variables in less urbanized regions of China. In the rapid urbanization areas such as eastern coastal regions, only presents the Granger causality from surface air temperature to the fossil fuel CO₂ emissions. This is the first attempt to offer insights of local temperature variables response to the increasing CO₂ across urban China. Our integrated results are novel in exploring the contributions of expanding urban areas to CO₂ emissions across China, including anthropogenic and natural components of urban areas simultaneously. We believe that our findings have clear significance for local governments who strive for constructing low-carbon cities. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Meng Lina. / Thesis (Ph.D.) Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 203-218). / Abstracts also in Chinese.

China has been experiencing great economic development and fast urbanisation since its reforms and opening-up policy in 1978. However, these changes are reliant on consumption of primary energy, especially coal, characterised by high pollution and low efficiency. China’s greenhouse gas (GHG) emissions, with carbon dioxide (CO2) being the most significant contributor, have also been increasing rapidly in the past three decades. Responding to both domestic challenges and international pressure regarding energy, climate change and environment, the Chinese government has made a point of addressing climate change since the early 2000s. This thesis provides a comprehensive analysis of China’s CO2 emissions and policy instruments for mitigating climate change. In the analysis, China’s CO2 emissions in recent decades were reviewed and the Environmental Kuznets Curve (EKC) hypothesis examined. Using the mostly frequently studied macroeconomic factors and time-series data for the period of 1980-2008, the existence of an EKC relationship between CO2 per capita and GDP per capita was verified. However, China’s CO2 emissions will continue to grow over coming decades and the turning point in overall CO2 emissions will appear in 2078 according to a crude projection. More importantly, CO2 emissions will not spontaneously decrease if China continues to develop its economy without mitigating climate change. On the other hand, CO2 emissions could start to decrease if substantial efforts are made. China’s present mitigation target, i.e. to reduce CO2 emissions per unit of GDP by 40-45% by 2020 compared with the 2005 level, was then evaluated. Three business-as-usual (BAU) scenarios were developed and compared with the level of emissions according to the mitigation target. The calculations indicated that decreasing the CO2 intensity of GDP by 40-45% by 2020 is a challenging but hopeful target. To study the policy instruments for climate change mitigation in China, domestic measures and parts of international cooperation adopted by the Chinese government were reviewed and analysed. Domestic measures consist of administration, regulatory and economic instruments, while China’s participation in international agreements on mitigating climate change is mainly by supplying certified emission reductions (CERs) to industrialised countries under the Clean Development Mechanism (CDM). The most well-known instruments, i.e. taxes and emissions trading, are both at a critical stage of discussion before final implementation. Given the necessity for hybrid policies, it is important to optimise the combination of different policy instruments used in a given situation. The Durban Climate Change Conference in 2011 made a breakthrough decision that the second commitment period under the Kyoto Protocol would begin on 1 January 2013 and emissions limitation or reduction objectives for industrialised countries in the second period were quantified. China was also required to make more substantial commitments on limiting its emissions. The Chinese government announced at the Durban Conference that China will focus on the current mitigation target regarding CO2 intensity of GDP by 2020 and will conditionally accept a world-wide legal agreement on climate change thereafter. However, there will be no easy way ahead for China. / QC 20120424

Chronic seismic hazards and resulting secondary impacts as natural conditions of the country, and loss of robust building and prudent settlement practices as aggravated by rapid population growth make cities the most vulnerable geographical and social entities in Turkey. In contrast, Turkish disaster policy is solely focused on post-disaster issues and no incentives or provision exist to encourage risk analysis or risk mitigation approaches, despite current international efforts. For the development of risk reduction policies an essential step is to prioritize settlements according to their vulnerability levels. This could be determined by hazard probabilities and attributes of the building stock of each settlement. Measurement of vulnerability levels allows the ordering of settlements into risk categories. Vulnerability levels of settlements are then assumed to depend on a number of attributes of cities to explore if vulnerability could be related to a set of urban properties. Results of statistical analyses indicate that total building loss is related to the ratio of population over the total number of buildings in mid-range settlements, and directly related to population in metropolitan cities. Relative loss on the other hand is related with rate of agglomeration and development index in almost every size category of settlements. Observations provide guiding principles for effective mitigation practices in Turkey by ordering settlements and offer means of differential implementation. These could contribute to improved safety measures in urban standards, building codes, building supervision procedures, insurance systems, investment priorities, and Law (6306) on Redevelopment of Areas under Disaster Risk.

Decision-makers in cities have realized their pivotal role in addressing climate change, and they are responding accordingly. This thesis presents three papers that explore the process of responding to climate change in cities, highlighting the situation in selected global cities with varying economies and development priorities. The methodology for conducting an urban greenhouse gas inventory in three Chinese cities is detailed in the first paper, illustrating issues of economic development and climate change mitigation in a transitional economy. Next, the greenhouse gas emissions savings of various strategic mitigation plans are quantified for Toronto, demonstrating the aggressive actions needed in developed cities to approach carbon neutrality. The third paper explores issues associated with climate change in three developing cities, emphasizing the need for synergic development incorporating strategies for both mitigation and adaptation. The thesis concludes with an overview of the importance of innovation and further research to future responses to climate change.

Decision-makers in cities have realized their pivotal role in addressing climate change, and they are responding accordingly. This thesis presents three papers that explore the process of responding to climate change in cities, highlighting the situation in selected global cities with varying economies and development priorities. The methodology for conducting an urban greenhouse gas inventory in three Chinese cities is detailed in the first paper, illustrating issues of economic development and climate change mitigation in a transitional economy. Next, the greenhouse gas emissions savings of various strategic mitigation plans are quantified for Toronto, demonstrating the aggressive actions needed in developed cities to approach carbon neutrality. The third paper explores issues associated with climate change in three developing cities, emphasizing the need for synergic development incorporating strategies for both mitigation and adaptation. The thesis concludes with an overview of the importance of innovation and further research to future responses to climate change.