实时控制系统中的任务模型及调度算法设计

控制系统的实时任务能否在规定的时限内完成依赖于调度算法的好坏。首先给出控制系统中实时任务模型，包括实时周期任务和实时非周期任务；然后，在考虑优先级倒置和非周期任务的基础上，介绍一种静态优化调度算法(RMS)；最后，对调度算法进行可调度性分析。     

广州市居民的旅游偏好和出游时间研究

根据2001年10月至2002年1月对广州702名市场进行的抽样调查资料，对广州市居民的旅游偏好和出游时间进行了分析研究，试图找出广州居民的旅游偏好和出游时间特征。     

网络时代高校德育教育的对策

在网络时代，人们的活动范围开始从实际领域向虚拟空间扩展，原本在地域文化基础上形成簟思想观念、价值取向等更多的受到了外来文花的冲击，人类整个思想文化领域正经历着深刻的变化。高校德育工作者务必抓住时机，积极寻找对策，充分发挥网络的优势，扬长避短，开辟德育教育的新天地。     

发展粮食期货市场 促进粮食市场化改革

随着粮食生产经营的全面市场化,健全和完善粮食期货市场有了更重要的现实意义:调节粮食供求,稳定粮食价格;优化粮食品种结构,推动产业化经营;为粮食企业提供避险渠道;减轻入世冲击,保护粮食安全。文章指出发展粮食期货市场的政策措施包括:推出大宗粮食期货交易品种;培育和发展套期保值用户;规范粮食现货市场;发展商品投资基金;开创场外交易;调整不符合国际惯例的法规政策。     

基于GASA算法的提前或拖期问题优化

针对企业生产的提前 /拖期问题,提出了提前 /拖期问题的数学模型,在此基础上,利用GASA混合优化策略优化之,既保留了传统遗传算法能很快达到最优值领域的优点,又通过结合模拟退火算法大大改善传统遗传算法在后期的收敛性。     

Endogenous human capital accumulation, comparative advantage and direct vs. indirect redistribution

Recently, several papers have reexamined the so-called production efficiency theorem and the Atkinson and Stiglitz theorem on commodity taxes in the optimal taxation literature. Naito [J. Public Econ. 71 (1999) 65] showed that indirect redistribution through production distortion or consumption distortion can Pareto-improve welfare and that the two theorems do not necessarily hold when different factors are imperfect substitutes and factor prices are endogenous. On the other hand, Saez J. Public Econ. (2002) forthcoming argued that in the long run, where human capital accumulation is endogenous, the two theorems are still valid. This paper develops reasonable alternative models where individuals accumulate human capital based on their comparative advantage. The present paper shows that the production efficiency theorem is not necessarily valid and that indirect redistribution from the able to the less able such as tariffs and production subsidies can increase efficiency even when skill accumulation is endogenous.     

房地产价格波动与投机行为--对中国14城市的实证研究

本文首先构建了适合中国的房地产投机理论模型,然后利用该模型对中国14个城市房地产价格波动与投机行为的关系进行实证研究.对14城市的时间序列数据研究结果表明各城市房地产投机水平都很高,个别城市更加突出.通过对14城市的截面数据分析,可以看出可支配收入对房地产价格没有显著影响,这些城市房地产价格的上升,主要是由投机来推动的,而且整体投机度非常高,说明房地产价格极大的偏离长期均衡值,市场出现了非理性繁荣,政府和产业部门应该采取适当的措施,积极引导消费者和投资者,为建立均衡的房地产市场提供良好的宏观和微观环境.     

Feminist Ecological Economics and Sustainability

Synopsis New developments in feminist ecological economics and ecofeminist economics are contributing to the search for theories and policy approaches to move economies toward sustainability. This paper summarizes work by ecofeminists and feminist ecological economists which is relevant to the sustainability challenge and its implications for the discipline of economics. Both democracy and lower material throughputs are generally seen as basic principles of economic sustainability. Feminist theorists and feminist ecological economists offer many important insights into the conundrum of how to make a democratic and equity-enhancing transition to an economy based on less material throughput. These flow from feminist research on unpaid work and caring labor, provisioning, development, valuation, social reproduction, non-monetized exchange relationships, local economies, redistribution, citizenship, equity-enhancing political institutions, and labor time, as well as creative modeling approaches and activism-based theorizing.      

Monitoring the mean and the variance of a stationary process

We deal with the problem of how deviations in the mean or the variance of a time series can be detected. Several simultaneous control charts are introduced which are based on EWMA (exponentially weighted moving average) statistics for the mean and the empirical variance. The combined X − S² EWMA chart is extended to time series. Further simultaneous charts are considered. The comparision of these schemes shows that the residual attempt must be favored if a variance change is present.     

Nonlinear IV unit root tests in panels with cross-sectional dependency

We propose a unit root test for panels with cross-sectional dependency. We allow general dependency structure among the innovations that generate data for each of the cross-sectional units. Each unit may have different sample size, and therefore unbalanced panels are also permitted in our framework. Yet, the test is asymptotically normal, and does not require any tabulation of the critical values. Our test is based on nonlinear IV estimation of the usual augmented Dickey–Fuller type regression for each cross-sectional unit, using as instruments nonlinear transformations of the lagged levels. The actual test statistic is simply defined as a standardized sum of individual IV t-ratios. We show in the paper that such a standardized sum of individual IV t-ratios has limit normal distribution as long as the panels have large individual time series observations and are asymptotically balanced in a very weak sense. We may have the number of cross-sectional units arbitrarily small or large. In particular, the usual sequential asymptotics, upon which most of the available asymptotic theories for panel unit root models heavily rely, are not required. Finite sample performance of our test is examined via a set of simulations, and compared with those of other commonly used panel unit root tests. Our test generally performs better than the existing tests in terms of both finite sample sizes and powers. We apply our nonlinear IV method to test for the purchasing power parity hypothesis in panels.