No description available.

本論文集收錄了三篇關於儲蓄的宏觀經濟學及其相關領域的文章。 / 第一篇文章討論儲蓄和跨期替代問題。在這篇文章中我們研究在新古典增長模型中，當採用不為1的要素替代彈性和非常數的跨期替代彈性時產生不同的儲蓄動態的問題。使用一般化的效用函數和生產函數，我們的結論覆蓋了現實中的各種儲蓄率變化形式，包括單調遞增、遞減、鐘形和U型。在此我們使用Stone-Geary效用函數和CES生產函數作為一個特例來說明問題。使用相點陣圖分析方法，我們得出了可以導致不同儲蓄率動態的充分和必要條件。我們的數量測驗支持理論的結果。作為一個擴展，接下來我們討論了連續時間OLG模型中的儲蓄率動態。當放鬆偏好和技術兩方面的假設時，我們依然得出了類似於新古典模型的豐富的儲蓄率動態。 / 第二篇文章是一個關於可變IES假設的經驗研究。在這篇文章中我們研究了跨期替代彈性的跨國差異，以及在某一特定國家的增長路徑中其可能的變化。在估計中我們使用了不同形式的歐拉方程模型，尤其是具有Stone-Geary效用形式的約束條件的模型。我們使用東亞和南亞國家面板資料的研究不能拒絶遞增IES的假設。使用兩個典型亞洲國家：日本和韓國的時間序列研究也得出了IES在經濟增長過程中遞增的結論。這一結果給第一章中的理論發現提供了經驗支持，與這些國家的儲蓄率動態變化情況也是相吻合的。 / 第三篇文章在一個具有不對稱生產技術的兩國開放經濟模型中採用數量方法探討了中國的高儲蓄率和經常帳戶不平衡問題。我們估計了中國和OECD國家的生產函數參數，發現中國生產函數中的要素替代彈性和資本份額都要明顯大於發達國家，其中中國的要素替代彈性大於1，而資本份額大于0.5，與文獻中的結論相近。在數量研究部分，我們發現在有中國式的高TFP增長之時，具有估計出的不對稱技術參數的模型能產生高得多的儲蓄和經常帳戶餘額，在2000年之前尤其與現實資料相吻合。而具有對稱技術參數的標準模型則得出了高經常帳戶赤字的結論，這與實際情況是矛盾的。 / This thesis consists of three essays on the issue of macroeconomics of saving and its related areas. / The first essay is on saving and intertemporal substitution. In this essay we study the possibility to generate different saving dynamics with a standard neoclassical growth framework, when allowing non-unitary factor elasticity of substitution (EOS) and non-constant intertemporal elasticity of substitution (IES). When employing both generalized utility and production function, our results can encompass all the varieties of saving patterns that are possible in the evidence, including monotonically increasing, decreasing, hump-shaped and U-shaped. We use the model with Stone-Geary utility and CES production function as a special case for illustration. Following the phase diagram approach, we have derived the necessary and sufficient conditions for the different saving dynamics. Our numerical tests can also support the theoretical findings. We have also studied the saving dynamics in another workhorse model, the OLG model with continuous time as an extension. When relaxing the assumptions in preference and technology, we also find rich transitional dynamics of saving that are close to those in the neoclassical model. / The second essay is an empirical study on the variable IES assumption. In this essay we study the cross-country difference with the intertemporal elasticity of substitution, as well as its possible changes in one country's growth transition. We test different forms of the Euler equation model, especially one with an increasing IES restriction as is implied by the Stone-Geary style utility function. Our estimation with the east and south Asia country panel data can not reject the increasing IES assumption. A time-series study on two typical Asian Country, Korea and Japan's IES also indicates an increasing IES in their growth path. These results provide some support to the theoretical findings in Chapter I, and are consistent with the countries' saving patterns in history. / The third essay investigates China's high saving rate and current account imbalance problem quantitatively in a two-country open economy macroeconomic model when using asymmetric production technologies. We estimate the production parameters for China and the OECD countries, and find that China's elasticity of substitution (EOS) and capital share in production are both higher than those of developed countries. While the estimated EOS of China is above one, the capital share of it is above 0.5 and close to the literature value. In the quantitative study, when there is high TFP growth rate, the model with estimated EOS and capital share can generate much higher saving and current account balance for China, which match the real series very well especially before the year 2000, while the standard model with symmetric production parameters predicts large current account deficits and is contrary to the evidence. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Luo, Gongshu. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Abstract --- p.i / Contents --- p.iv / Chapter 1 --- Saving and Intertemporal Substitution --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Saving in the Neoclassical Model --- p.6 / Chapter 1.2.1 --- Model Specification --- p.6 / Chapter 1.2.2 --- Equilibrium Saving Rate --- p.7 / Chapter 1.2.3 --- Transitional Dynamics of Saving --- p.8 / Chapter 1.2.4 --- A Numerical Study --- p.21 / Chapter 1.3 --- Saving in the Perpetual Youth Model --- p.25 / Chapter 1.3.1 --- Model Specification --- p.26 / Chapter 1.3.2 --- Different Utility Forms --- p.28 / Chapter 1.3.3 --- Saving Dynamics --- p.34 / Chapter 1.3.4 --- A Numerical Study --- p.35 / Chapter 1.4 --- Conclusion --- p.36 / Reference --- p.38 / Chapter Tables and Figures --- p.40 / Chapter 2 --- An Empirical Study on Intertemporal Substitution --- p.49 / Chapter 2.1 --- Introduction --- p.49 / Chapter 2.2 --- Theory of Variable IES --- p.54 / Chapter 2.3 --- Estimating IES --- p.59 / Chapter 2.3.1 --- The Euler Equation Approach --- p.60 / Chapter 2.3.2 --- Liquidity Constraint Model --- p.62 / Chapter 2.3.3 --- Extensions on Estimating IES --- p.63 / Chapter 2.3.4 --- On Testing Variable IES --- p.64 / Chapter 2.4 --- Methodology --- p.67 / Chapter 2.4.1 --- The Non-linear GMM Method --- p.67 / Chapter 2.4.2 --- Model to be Tested --- p.69 / Chapter 2.5 --- Data Issues --- p.71 / Chapter 2.6 --- Estimation Results --- p.75 / Chapter 2.6.1 --- Cross-country Panel Study --- p.75 / Chapter 2.6.2 --- Single-country Time Series Study --- p.78 / Chapter 2.7 --- Conclusion --- p.82 / Reference --- p.84 / Chapter Tables and Figures --- p.87 / Chapter 3 --- Production Differences and Current Account Imbalance --- p.94 / Chapter 3.1 --- Introduction --- p.94 / Chapter 3.2 --- Estimation on Capital Share and EOS --- p.100 / Chapter 3.2.1 --- Model Specification --- p.101 / Chapter 3.2.2 --- Data Construction --- p.103 / Chapter 3.2.3 --- Estimation Results --- p.104 / Chapter 3.3 --- A Two-Country Open Economy Model --- p.107 / Chapter 3.3.1 --- Model Setup --- p.107 / Chapter 3.3.2 --- Competitive Equilibrium --- p.109 / Chapter 3.3.3 --- Equilibrium conditions --- p.109 / Chapter 3.4 --- A Quantitative Study --- p.110 / Chapter 3.4.1 --- Calibration --- p.111 / Chapter 3.4.2 --- Parameters --- p.112 / Chapter 3.4.3 --- Initial and Steady-State Conditions --- p.112 / Chapter 3.4.4 --- Basic Results --- p.113 / Chapter 3.4.5 --- Some Special Features of the Model --- p.116 / Chapter 3.4.6 --- Counterfactural Experiments and Sensitivity Analysis --- p.117 / Chapter 3.4.7 --- A Discussion on the Role of IES --- p.119 / Chapter 3.5 --- Conclusion --- p.121 / Reference --- p.123 / Chapter Tables and Figures --- p.125

As manufacturers, the automotive industry, and many other sectors face an increasingly competitive global business environment; they seek opportunities to reduce production costs by reducing energy consumption. Energy costs have become one of the fastest-rising expenses of doing business, and the industrial sector is rushing to implement new energy conservation initiatives. Pressurized air, as an important source of energy, has been widely used by various industries, providing simple solutions for automated lines. In this project, an Accumulator-Based Equalization (ABE) strategy was combined with a knowledge-based PWM (Pulse Width Modulation) protocol, and then incorporated into an integrated solenoid valve to increase the energy efficiency of pneumatic systems through the optimization of ow consumption. Modeling and simulation of the proposed system was carried out to assess the proposed ideas and reduce the cost of system developments. An experimental setup was constructed to assess the performance of the proposed strategy when implemented on configured pneumatic control valves. Equalization was performed at home positions of a typical linear actuator, where the chambers of the pneumatic actuators were momentarily connected to each other. Furthermore, during the extension and retraction, a knowledge-based PWM signal was applied to the valves to maintain the actuator dynamics in an acceptable posture. To obtain the knowledge-based PWM signal, an expert-fuzzy controller was designed to control the speed of the actuator. This knowledge-based protocol was based on fuzzy structures, which were implemented on the configured pneumatic valves in an open-loop fashion to decrease the amount of ow consumption without compromising the dynamic performance of the pneumatic actuators. The identified duty cycles profiles from the expert fuzzy controller were implemented on an open-loop system. It was observed that, while an open-loop system is used, the pressurized air can be saved about 20% under 50 N load and almost 10% under 150 N load. "Smoothness index" was defined as a measure of the piston motion smoothness when applying the proposed strategies. In addition to smoothness of the motion in the closed-loop control methods, the energy-saving results were compared to the results of the open-loop system and the performance under different conditions was evaluated.

As manufacturers, the automotive industry, and many other sectors face an increasingly competitive global business environment; they seek opportunities to reduce production costs by reducing energy consumption. Energy costs have become one of the fastest-rising expenses of doing business, and the industrial sector is rushing to implement new energy conservation initiatives. Pressurized air, as an important source of energy, has been widely used by various industries, providing simple solutions for automated lines. In this project, an Accumulator-Based Equalization (ABE) strategy was combined with a knowledge-based PWM (Pulse Width Modulation) protocol, and then incorporated into an integrated solenoid valve to increase the energy efficiency of pneumatic systems through the optimization of ow consumption. Modeling and simulation of the proposed system was carried out to assess the proposed ideas and reduce the cost of system developments. An experimental setup was constructed to assess the performance of the proposed strategy when implemented on configured pneumatic control valves. Equalization was performed at home positions of a typical linear actuator, where the chambers of the pneumatic actuators were momentarily connected to each other. Furthermore, during the extension and retraction, a knowledge-based PWM signal was applied to the valves to maintain the actuator dynamics in an acceptable posture. To obtain the knowledge-based PWM signal, an expert-fuzzy controller was designed to control the speed of the actuator. This knowledge-based protocol was based on fuzzy structures, which were implemented on the configured pneumatic valves in an open-loop fashion to decrease the amount of ow consumption without compromising the dynamic performance of the pneumatic actuators. The identified duty cycles profiles from the expert fuzzy controller were implemented on an open-loop system. It was observed that, while an open-loop system is used, the pressurized air can be saved about 20% under 50 N load and almost 10% under 150 N load. "Smoothness index" was defined as a measure of the piston motion smoothness when applying the proposed strategies. In addition to smoothness of the motion in the closed-loop control methods, the energy-saving results were compared to the results of the open-loop system and the performance under different conditions was evaluated.

Transient heat transfer phenomena in the rotational molding of plastic parts are modeled in this study. Natural convection and radiation from the furnace and flue gases to the mold housing are analyzed. Other models include transient heat transfer through the mold, single-phase conduction through the particulate plastic material prior to phase change, melting of the plastic and heating of the liquid pool. Subsequent staged cooling of the mold and solidification of the plastic using a combination of free and forced convection and radiation, are also modeled. The mold wall, melt, and solidified plastic regions are divided into a number of finite segments to track the temperature variation with time during the molding process. The corresponding variations in masses and thicknesses of the melt and solidified plastic regions are estimated. This information is used to estimate the energy consumption rates for various phases of the process. The model is applied to a specific molding process in a commercial rotational molding plant. Parametric studies of the effect of heating and cooling durations on the plastic temperatures and the energy consumption rates are conducted. These analyses provide insights about opportunities for optimization of the heating and cooling schedules to reduce overall energy consumption and improve throughput. The overall energy and gas consumption for the rotational molding process, taking into consideration the thermal mass of the auxiliary housing (steel) required to hold the molds, is estimated on a per-batch basis. In addition, a preliminary design for an alternative system for heating and cooling the molds using a high temperature heat transfer fluid (HTF) flowing through jackets integral to the molds is proposed.

Thesis--Copenhagen. / Errata slip inserted. Includes bibliographical references (p. [238]-246).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on June 17, 2009) Vita. Includes bibliographical references.

Dissertation (PhD. in Economics)--University of Southern California, 1976. / "October 1976." Includes bibliographical references (p. 282-298).

Thesis (duktūrāh)--Jāmiʻat al-Iskandarīyah. / Includes bibliographical references (p. [435]-446).