Autonomous pointing control of a large satellite antenna subject to parametric uncertainty

With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna’s optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional–derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness

Is the provision of more timely earnings information good for the Chinese stock market? : evidence from investor reactions to management earnings forecasts

Since 2001, publicly listed companies in China have been required by the Chinese Securities and Regulatory Commission (CSRC), the Shanghai Exchange and the Shenzhen Exchange to issue management earnings forecasts when they anticipate that earnings will be negative or change substantially from the previous period. This study examines the consequences and implications of this disclosure regulation. I find that the earnings forecasts are associated with an earlier incorporation of relevant earnings information into stock prices. However, I also find evidence that is consistent with the presence of overreactions to forecasts of extreme earnings changes. My study offers a cautionary note about the policy of mandating listed firms to issue earnings forecasts in a stock market that is dominated by individual investors

Essays on economic development of China

China's rapid economic growth and social transitions have drawn substantial recent attention. However, there is still limited understanding of these phenomena and the mechanisms behind them. This dissertation investigates three aspects of China's development: education, female labor supply and responses to natural shocks. Chapter 1 sheds light on the option value of education by studying the impact of China's college enrollment expansion on educational attainment at the high school level. Standard human capital models without uncertainty rarely address the importance of the option value of education -- the opportunity that a certain level of education provides to obtain a higher level of education. Therefore, changes in option values can affect human capital investment decisions. Combining survey data with provincial statistics and applying a difference-in-differences method, I find that China's college expansion significantly increased the probabilities of enrolling in and completing high school. The probability of completing high school increased more than that of enrolling in high school. Female students benefited more, as did children whose mother had a high school degree. Chapter 2 studies the relationship between fertility and female labor supply. Many empirical studies find a negative correlation between the two, however the evidence on causal effects is weaker because fertility is endogenous. This paper studies the effects of childbearing on women's labor supply and earnings using a plausibly exogenous change, the relaxation of China's One Child Policy, as an instrument for family size. The main findings are that total fertility has no significant impact on time of working as a wage earner, but children under six have a negative effect. Neither total fertility nor children under six affect women's farming time or annual income. Chapter 3 explores the long-term consequences of China's Great Famine from 1959 to 1961. Several studies have investigated the causes of the famine, yet little empirical work examined its consequences. This paper examines a set of health and socioeconomic outcomes that have not been studied. I find a significant positive selection in the height of survivors born during the famine. Individuals born during the famine received less education than those born before or after the famine, were more likely to work in agriculture when starting to work and transferred less money to their parents

COMPARING GOAL SETTING APPROACHES TO BOOST COMPUTER-RELATED PRO-ENVIRONMENTAL BEHAVIORS

This research focuses on improving individuals’ pro-environmental behaviors related to information technology and system use. To do so, we draw on and extend goal-setting theory by comparing three goal interventions: goal-setting, goal-setting plus implementation plans, and goal-setting with both implementation plans and visualization of success. Two longitudinal studies examine individuals’ selfset goals: the first examines employees’ computer-based electricity usage in the workplace over six weeks and the second utilizes a diary approach method over four weeks to examine the effects of different goal setting conditions on students’ environmental outcomes. Both studies find that setting goals increases pro-environmental behaviors. However, rebound effects can occur when interventions are removed. Visualization of success appears to reduce this rebound effect and we suggest that future research continue to investigate methods for reducing rebound, including the roles of values and multiple goals on the efficacy of goal-setting. This paper contributes to Green IS research in several ways: conceptually (by responding to calls for more theory-based research), methodologically (by measuring objective computer-based energy usage in study 1 and by utilizing a diary method in study 2), and practically (by demonstrating the effectiveness of visualization to goal setting)

Estimation of Firm-Level Productivity in the Presence of Exports: Evidence from China's Manufacturing

Motivated by the longstanding interest of economists in understanding the nexus between firm productivity and export behavior, this paper develops a novel structural framework for control-function-based nonparametric identification of the gross production function and latent firm productivity in the presence of endogenous export opportunities that is robust to recent unidentification critiques of proxy estimators. We provide a workable identification strategy, whereby the firm's degree of export orientation provides the needed (excluded) relevant independent exogenous variation in endogenous freely varying inputs, thus allowing us to identify the production function. We estimate our fully nonparametric IV model using the Landweber-Fridman regularization with the unknown functions approximated via artificial neural network sieves with a sigmoid activation function which are known for their superior performance relative to other popular sieve approximators, including the polynomial series favored in the literature. Using our methodology, we obtain robust productivity estimates for manufacturing firms from twenty eight industries in China during the 1999-2006 period to take a close look at China's exporter productivity puzzle, whereby exporters are found to exhibit lower productivity levels than non-exports

Risk Modeling of DP Operation for Offshore Tandem Offloading

The paper proposes a risk model to warn shuttle tanker drive-off previously and detect it punctually, and proposes a risk decision support model to generate, evaluate and select a best vessel maneuvering plan to avoid the shuttle tanker collision with FPSO. The central concern is to establish an Online Decision Support System to collect and analyze the real-time data by these two models, so as to help the drive-off vessel recovered successfully. Fault Tree Analysis is used to find the root causes to detect the vessel drive-off. Event Tree Analysis is used to evaluate and compare the different risk pictures of shuttle tanker and FPSO layout. Bayesian Risk Influence Diagram is used to generate maneuvering plans. In addition, the system deploys vessel collision consequence model and vessel collision probability model to evaluate the plans. A Human Machine Interface is designed to provide a viewable screen about operation information. In addition, a contingency plan for drive-off recovery and position reference selection procedure are generated for daily operation