一种基于区域搜索的全局运动估计与补偿算法

开展全局运动估计与补偿研究是进行动态目标检测中的基础和前提。在总结现有运动估计与补偿方法的基础上,提出一种基于图像分割区域的运动性和大小的全局运动估计与补偿算法。首先,通过建立区域搜索的全局运动模型,同时进行区域定性分割和区域大小排序;然后,根据误差最小化准则在指定的分割区域中进行线性递归搜索,利用门限准则寻找出最佳的运动估计参数;最后,根据双线性内插法获得运动位移量。实验结果比较可知,所提算法较三步搜索算法(TSS)和全局搜索算法(FSA)等传统算法具有更高的准确性(图像平移帧差)和实时性(算法运行时间),能够很好地实现运动背景的全局校正。     

ALGORITHMIC METHODS FOR SINGLE SERVER SYSTEMS WITH REPEATED ATTEMPTS

In many practical situations customers applying for service and finding the server busy will not join a queue, but make a new attempt to enter service after some time. In this paper we study single server systems with repeated attempts both for infinite-source input and finite-source input where the service times are general and the reattempt times are exponential. Numerically stable recursion schemes are derived by which the time-average and customer-average steady-state probabilities can be effectively computed.     

On Mixed and Compound Mixed Poisson Distributions

Recursive formulae are derived for the evaluation of the t-th order cumulative distribution function and the t-th order tail probability of compound mixed Poisson distributions in the case where the derivative of the logarithm of the mixing density can be written as a ratio of polynomials. Also, some general results are derived for the evaluation of the t-th order moments of stop-loss transforms. The recursions can be applied for the exact evaluation of the probability function, distribution function, tail probability and stop-loss premium of compound mixed Poisson distributions and the corresponding mixed Poisson distributions. Several examples are also presented.     

关于Lucas多项式的几个恒等式

本文利用Lucas多项式的递推关系和Lucas多项式的表达式,给出了关于Lucas多项式的一些恒等式。     

Forecasting with leading indicators: Does the new index lead?

There are very few economic variables that capture as much public attention as the Composite Index of Leading Indicators (CLI). Designed as an early warning system for signaling recessions and recoveries in business cycles, CLI now has significant influence over the expectations of decision makers and market participants. Since its inception in 1938, the index has undergone many revisions, the last of which took effect in March 1989. In this study we evaluate the new index. A number of filters, including the Bayesian sequential probability recursion and the rule of three consecutive declines in CLI, are used to evaluate the information content of CLI in forecasting the turning points in the economy. We also report the result of our forecasting experiment to gauge the marginal value of the new index to improve forecasts of variables such as the unemployment rate, index of industrial production, GNP, sales, profit, consumption and housing starts.     

Linguistics and Economics: Is Entrepreneurship Innate?

One of the great scientific achievements of the second half of the twentieth century was the advance in linguistics. Noam Chomsky was one of its foremost exponents. Chomsky and his followers claim that human beings have an inbuilt ‘language acquisition device’ which allows children to acquire language with extraordinary ease. Language is as much part of human nature as flying is that of birds. This paper argues that, like language, the propensity to trade is an inbuilt characteristic of human beings. Language permeates all human faculties including the ability to plan for the future. As a result human economic activity shares many important features with language, in particular its recursive and unbounded character. There is also evidence that the concept of property is innate. It follows that attempts to frustrate or limit the exercise of property rights and their use in trade works against the grain of human nature. Limits on the natural expression of entrepreneurship may be as damaging as other constraints on human flourishing.     

基于契约结构的模块化设计及其演进

任务结构与参数结构具有“同构性”，任务结构对参数结构“赋值”并实现设计完善：参数结构“改造”可推动设计演进．但又取决于任务之间相互依赖关系。任务结构模块化就是这样一种“改造”．但须以规则契约结构为基础，因其是任务之间纵向依赖关系的次优性预先决策。设计目的在于发现和追求价值，但须由市场契约结构为任务结构提供价值背景．而价值背景资本化为模块化任务结构提供了有效“整合”。“递归性”模块化操作不仅创造设计期权，也缩小设计“规模”和“下放”设计权限，有利于吸纳来自底层的创造力量．促进了设计规则市场的形成，并不断激励设计演进。     

The accuracy of earnings forecasts in IPO prospectuses on the Kuala Lumpur Stock Exchange

This paper examines the accuracy of earnings forecasts made by managers of Malaysian initial public offerings (IPOs) during the period 1984–1995. It is a mandatory requirement for Malaysian IPOs to furnish earnings forecasts together with the opinions thereon of the auditors and the lead underwriter in their prospectuses. Their accuracy is measured by forecast errors, absolute forecast errors, squared forecast errors and standardised forecast errors. The results suggest that, on average, managers under-forecast earnings by 33.37%. A comparison with the naive no change model in earnings suggests that 96 out of 122 companies outperform this model. A number of company specific characteristics (size, age, forecast interval, gearing, proportion of shares retained by owners, auditor reputation and industry) are tested. The results reveal that both the age and industry classification of the company are statistically significant, and that management earnings forecasts are particularly inaccurate where firms experience a decline in earnings. Key words: accuracy of prospectus earnings forecasts, initial public offerings, accounting in Malaysia.     

用母函数法求菲波那契数列an值的递归算法的时间复杂度

介绍时间复杂度和母函数法，并利用母函数法分析求菲波那契数列第n项an的值递归算法的时间复杂度，进而讨论同类递归算法的问题的规模n的函数f(n）的母函数。     

An Aggregation Theorem for the Valuation of Equity Under Linear Information Dynamics

We state an Aggregation Theorem which shows that the recursion value of equity is functionally proportional to its adaptation value. Since the recursion value of equity is equal to its book value plus the expected present value of its abnormal earnings, it follows that the adaptation value of equity can normally be determined by a process of simple quadrature. We demonstrate the application of the Aggregation Theorem using two stochastic processes. The first uses the linear information dynamics of the Ohlson (1995) model. The second uses linear information dynamics based on the Cox, Ingersoll and Ross (1985)'square root' process. Both these processes lead to closed form expressions for the adaptation and overall market value of equity. There are, however, many other processes which are compatible with the Aggregation Theorem. These all show that the market value of equity will be a highly convex function of its recursion value. The empirical evidence we report for UK companies largely supports the convexity hypothesis.