Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15002号 / 工博第3176号 / 新制||工||1477(附属図書館) / 27452 / UT51-2009-R726 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 岡田 憲夫, 教授 小林 潔司, 教授 多々納 裕一 / 学位規則第4条第1項該当

Energy-economy models are important tools used by policy-makers and researchers to design effective climate policy. However, there has been limited research that compares models against consistent characteristics to understand their impacts on climate policy projections. This can make it difficult for policy-makers to identify suitable models for their specific policy questions and develop effective climate policies. A web-based survey of energy-economy model users and developers in Canada’s public, private, and non-profit sectors (n=14) was conducted to systematically compare seventeen models against a framework of seven characteristics: technology characteristics, micro-, and macro-economic characteristics, policy representations, treatment of uncertainty, high-resolution spatial and temporal representations, and data transparency. It was found that for the most part, models represent technology, micro-, and macro-economic characteristics according to the classic typology of bottom-up, top-down, and hybrid models. However, our findings show that several modelling evolutions have occurred. Some top-down models can explicitly represent technologies and some bottom-up models incorporate microeconomic characteristics. Models differ in the types of policies they can simulate, sometimes underrepresenting performance regulations, government procurement, and research and development programs. All models incorporate at least one type of uncertainty analysis, models infrequently have high-resolution spatial and/or temporal representations, and most models lack publicly accessible methodological documents. Implications for researchers and policy-makers that use energy-economy models and/or develop policies are discussed. / Graduate

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The global greenhouse gas CO2 emission from the transportation sector is very significant. To reduce this gas emission, EU has set an average target of not more than 95 CO2/km for new passenger cars by the year 2020. A great reduction is still required to achieve the CO2 emission target in 2020, and many different approaches are being considered. This thesis focuses on the thermal management of the engine as an area that promise significant improvement of fuel efficiency with relatively small changes. The review of the literature shows that thermal management can improve engine efficiency through the friction reduction, improved air-fuel mixing, reduced heat loss, increased engine volumetric efficiency, suppressed knock, reduce radiator fan speed and reduction of other toxic emissions such as CO, HC and NOx. Like heat loss and friction, most emissions can be reduced in high temperature condition, but this may lead to poor volumetric efficiency and make the engine more prone to knock. The temperature trade-off study is conducted in simulation using a GT-SUITE engine model coupled with the FE in-cylinder wall structure and cooling system. The result is a map of the best operating temperature over engine speed and load. To quantify the benefit of this map, eight driving styles from the legislative and research test cycles are being compared using an immediate application of the optimal temperature, and significant improvements are found for urban style driving, while operation at higher load (motorway style driving) shows only small efficiency gains. The fuel consumption saving predicted in the urban style of driving is more than 4%. This assess the chance of following the temperature set point over a cycle, the temperature reference is analysed for all eight types of drive cycles using autocorrelation, lag plot and power spectral density. The analysis consistently shows that the highest volatility is recorded in the Artemis Urban Drive Cycle: the autocorrelation disappears after only 5.4 seconds, while the power spectral density shows a drop off around 0.09Hz. This means fast control action is required to implement the optimal temperature before it changes again. Model Predictive Control (MPC) is an optimal controller with a receding horizon, and it is well known for its ability to handle multivariable control problems for linear systems with input and state limits. The MPC controller can anticipate future events and can take control actions accordingly, especially if disturbances are known in advance. The main difficulty when applying MPC to thermal management is the non-linearity caused by changes in flow rate. Manipulating both the water pump and valve improves the control authority, but it also amplifies the nonlinearity of the system. Common linearization approaches like Jacobian Linearization around one or several operating points are tested, by found to be only moderately successful. Instead, a novel approach is pursued using feedback linearization of the plant model. This uses an algebraic transformation of the plant inputs to turn the nonlinear systems dynamics into a fully or predominantly linear system. The MPC controller can work with the linear model, while the actual control inputs are found using an inverse transformation. The Feedback Linearization MPC of the cooling system model is implemented and testing using MathWork Simulink®. The process includes the model transformation approach, model fitting, the transformation of the constraints and the tuning of the MPC controller. The simulation shows good temperature tracking performance, and this demonstrates that a MPC controller with feedback linearization is a suitable approach to thermal management. The controller strategy is then validated in a test rig replicating an actual engine cooling system. The new MPC controller is again evaluated over the eight driving cycles. The average water pump speed is reduced by 9.1% compared to the conventional cooling system, while maintaining good temperature tracking. The controller performance further improves with future disturbance anticipation by 20.5% for the temperature tracking (calculated by RMSE), 6.8% reduction of the average water pump speed, 47.3% reduction of the average valve movement and 34.0% reduction of the average radiator fan speed.

L’objectif est d’analyser les déterminants et les mécanismes de transmission de la politique monétaire en Chine au cours des deux décennies passées. Elle contribue à la littérature par le biais de deux nouvelles mesures de la politique monétaire en Chine, l'une combinant les instruments utilisés par la banque centrale et l'autre basée sur les discours de la banque centrale sur la politique monétaire. Ces deux approches permettent de prendre en compte le comportement complexe et adaptatif de la banque centrale. Ces mesures permettent de mettre en évidence des changements substantiels dans le style de la politique à partir de 2002, plus graduelle et agressive envers l’inflation, en lien avec le début du mandat du gouverneur Xiaochuan, le processus de libéralisation des taux d’intérêt et l’ouverture commerciale et financière de la Chine. De plus, l’estimation d’un modèle à choix discret révèle une politique monétaire caractérisée par une politique accommodante sur l’inflation avant 2002 et un ciblage implicite de l’inflation à partir de 2002, similaire à celles du G3 pré- et post-1979. Enfin, cette thèse analyse les facteurs expliquant la déformation de la courbe des taux obligataires en Chine au cours de la dernière décennie. Alors que le contrôle des taux d’intérêt peut entraver l’usage de la courbe de taux comme référence pour évaluer les actifs risqués, celle-ci évolue bien en lien avec les autres instruments, la situation macroéconomique en Chine et de plus en plus aux communications de la banque centrale. Enfin, nos analyses révèlent l’influence de la politique monétaire américaine sur celle de la Chine et sur l’évolution de la courbe de taux sur la décennie passée. / The objective of this thesis is to enhance the understanding of the determinants and the transmission mechanisms of monetary policy in China over the last two decades. It contributes to the literature providing two new composite measures of monetary policy in China based on alternative approaches, one combining the large range of monetary policy instruments and the other based on central bank speeches. Both prove to be essential to take into account the complex and adaptive behavior of the People’s Bank of China (PBC). Our instrument-based monetary policy index emphasizes substantial changes in policy style towards smoother but more hawkish policy moves from 2002 onwards, consistent with the start of the mandate of Governor Zhou Xiaochuan, the interest rate liberalization process and the increasing trade and financial opening. Moreover, the estimation of a discrete-choice model implies a conduct of monetary policy characterized by an inflation-accommodating policy before 2002 and an implicit inflation targeting from 2002 onwards, which respectively resembles that of pre-1979 and post-1979 policy of the G3. Our thesis examines the deformation of the bond yield curve over the last decade to evaluate monetary policy transmission mechanisms. While regulated interest rates can hamper the use of the yield curve as benchmark for pricing risk, the latter moves in line with the other instruments, the macroeconomic situation, and increasingly to central bank communication, a crucial step toward a market oriented system. Finally, US monetary policy significantly affects monetary policy determinants and transmission mechanisms in China, particularly from its WTO accession in 2001.