Optimal investment with vintage capital: Equilibrium distributions

The paper concerns the study of equilibrium points, or steady states, of economic systems arising in modeling optimal investment with vintage capital, namely, systems where all key variables (capitals, investments, prices) are indexed not only by time but also by age. Capital accumulation is hence described as a partial differential equation (briefly, PDE), and equilibrium points are in fact equilibrium distributions in the variable of ages. A general method is developed to compute and study equilibrium points of a wide range of infinite dimensional, infinite horizon, optimal control problems. We apply the method to optimal investment with vintage capital, for a variety of data, deriving existence and uniqueness of equilibrium distribution, as well as analytic formulas for optimal controls and trajectories in the long run. The examples suggest that the same method can be applied to other economic problems displaying heterogeneity. This shows how effective the theoretical machinery of optimal control in infinite dimension is in computing explicitly equilibrium distributions. To this extent, the results of this work constitute a first crucial step towards a thorough understanding of the behavior of optimal paths in the long run.     

道路交通对城市空间形态的影响

城市交通方式和道路系统的布局对城市的规模和空间结构分布具有重大影响 ,同样它作为重要的基础设施和对外交流通道对城市的发展方向也起着重大的引导作用。本文通过对道路交通的研究 ,揭示了城市的演变规律和发展趋势。     

Philosophical Foundations of Eminent Hong Kong Chinese CEOs’ Leadership

Because of the importance of Confucian doctrines in shaping ethical business practices under Chinese leadership, revealing the roles of other Chinese ethical doctrines in modern Chinese leadership is informative. A thorough understanding of the ethical foundations of Chinese leadership is necessary for fruitful interaction with Chinese leaders, according to cultural fit theory. The present study illustrates the philosophical foundations of business management, based on dialogues with five eminent corporate executive officers (CEOs). It reveals that the CEOs practice a style of Chinese leadership synthesizing Confucian, Daoist, Mohist, and Legalist doctrines. The Confucian doctrines advocate benevolence, harmony, learning, loyalty, righteousness, and humility. They are the most prevalent tenets that support paternalism and collectivism. The Daoist doctrines emphasize flexibility and reversion (e.g., the principle that the weak can defeat the strong). They bolster the leader’s forbearance. The Mohist doctrines underpin thrift and working with the masses whereas the Legalist doctrines inculcate self-control and innovativeness. Hence, contemporary Chinese leadership does not rely exclusively on Confucian ethics and this reflects evolution over 1000s of years.     

Modeling society with statistical mechanics: an application to cultural contact and immigration

We introduce a general modeling framework to predict the outcomes, at the population level, of individual psychology and behavior. The framework prescribes that researchers build a cost function that embodies knowledge of what trait values (opinions, behaviors, etc.) are favored by individual interactions under given social conditions. Predictions at the population level are then drawn using methods from statistical mechanics, a branch of theoretical physics born to link the microscopic and macroscopic behavior of physical systems. We demonstrate our approach building a model of cultural contact between two cultures (e.g., immigration), showing that it is possible to make predictions about how contact changes the two cultures.     

我国股票市场的混沌探析

运用混沌理论对我国股票市场进行了实证研究 ,结果显示我国股票市场是一个低自由度的混沌系统 ,具有自相似的非线性结构 ,并且这种非线性结构可以用 GARCH( 1 ,1 )模型来拟合。     

汉语外来词的历史进程及其社会文化性浅析

外来词的大规模进入是改革开放后显著的语言现象。在分析这种语言现象的同时 ,梳理了历史上汉唐时期 ,晚清至“五四”前后这段时期的外来词状况。在此基础上 ,从语言学角度阐释中国文化由封闭性向开放性的过渡及中国现代语言文化的包容性特征     

试论市场营销中的文化因素及其影响

文化是企业市场营销环境中社会文化环境的重要组成部分，文化因素在营销活动中的影响和作用也越来越突出。本文从文化的基本含义入手，具体分析了文化的各个组成因素对市场营销活动产生的重大影响。最后强调了文化可以成为企业可控的营销要素这一理论的新观念。     

SEM图像分形维数的影响因素研究

以玻璃光纤、碳纤维纸和两种机加工表面样本的扫描电子显微镜图像为对象,运用盒维法研究了不同的放大倍数和采集过程中受到的噪声干扰对分形维数的影响.研究结果表明,随着放大倍数增大或随着椒盐噪声密度和高斯随机噪声方差的减小,分形维数下降.放大倍数和噪声对分形维数都有较大影响.在扫描电子显微镜图像分形维数的计算中,可以依据试样的结构特征选择合适的放大倍数,进行去噪处理后再计算图像的分形维数.     

Noisy chaotic dynamics in commodity markets

The nonlinear testing and modeling of economic and financial time series has increased substantially in recent years, enabling us to better understand market and price behavior, risk and the formation of expectations. Such tests have also been applied to commodity market behavior, providing evidence of heteroskedasticity, chaos, long memory, cyclicity, etc. The present evaluation of futures price behavior confirms that the resulting price movements can be random, suggesting noisy chaotic behavior. Prices could thus follow a mean process that is dynamic chaotic, coupled with a variance that follows a GARCH process. Our conclusion is that models of this type could be constructed to assist in forecasting prices in the short run but not over long run time periods.First version received: June 2001/Final version received: March 2003