实时系统开发与PEARL语言

本文讨论了实时系统的特征、开发方法、设计工具、实现手段工具等开发过程中的主要问题,论述了实时系统开发语言PEARL及该语言的对实时系统的主要支持.     

R ＆ D STRATEGIC INVESTMENT IN AN ASYMMETRICAL CASE

This article analyzes R ＆ D investment decisions in an asymmetrical case. The investment decisions share three important characteristics. First, the investment is completely irreversible. Second, there are two kinds of uncertainties over the future returns from the investment and over technology in R ＆ D process, respectively. Third, there is strategic competition in the asymmetrical case. This article presents the optimal investment threshold values and the optimal investment rule of high-efficient firm （leader）, and shows that the investment threshold values are reduced by competition of two firms. Finally, the mixed investment strategies for two firms, the probability that each firm separately exercises the option to invest, and the probability that two firms simultaneously exercise the option are given in the paper.     

The Optimal Solution of the Model with Physical and Human Capital Adjustment Costs

We prove that the model with physical and human capital adjustment costs has optimal solution when the production function is increasing return and the structure of vetor fields of the model changes substantially when the prodution function from decreasing return turns to increasing return. And it is shown that the economy is improved when the coefficients of adjustment costs become small.     

数字电视机顶盒综述

在介绍数字电视机项盒的定义、功能及分类的基础上，着重探讨了数字电视机顶盒的软、硬件结构以及该产品的市场前景等问题。     

图析宁波电视收视格局

文章对宁波的电视收视总体格局、晚间时段各电视频道的竞争态势,以及电视剧在宁波的收视情况作了由总及分的探讨和分析,将数据做成图表的形式形象、科学地解构了宁波电视的收视格局,对了解宁波电视收视情况和促进各台竞争提供了实际的参考价值.     

Robustness of alternative non‐linearity tests for SETAR models

In recent years there has been a growing interest in exploiting potential forecast gains from the non‐linear structure of self‐exciting threshold autoregressive (SETAR) models. Statistical tests have been proposed in the literature to help analysts check for the presence of SETAR‐type non‐linearities in an observed time series. It is important to study the power and robustness properties of these tests since erroneous test results might lead to misspecified prediction problems. In this paper we investigate the robustness properties of several commonly used non‐linearity tests. Both the robustness with respect to outlying observations and the robustness with respect to model specification are considered. The power comparison of these testing procedures is carried out using Monte Carlo simulation. The results indicate that all of the existing tests are not robust to outliers and model misspecification. Finally, an empirical application applies the statistical tests to stock market returns of the four little dragons (Hong Kong, South Korea, Singapore and Taiwan) in East Asia. The non‐linearity tests fail to provide consistent conclusions most of the time. The results in this article stress the need for a more robust test for SETAR‐type non‐linearity in time series analysis and forecasting. Copyright © 2004 John Wiley & Sons, Ltd.     

第二类三分子模型的球对称不稳定性

本文采用Hopf分岔理论对第二类三分子模型进行了详细的研究。结果表明,在固定边界条件下,自振荡不稳定性只能出现在稀释过程中。此外,本文还给出了时间周期解的解析表达式。     

离散边界条件系统的最优控制

研究离散边界条件系统的最优控制问题，给出了最优控制存在的必要条件，证明了此类系统最优控制仍有最大值原理成立。     

动态规划确定化学反应器序列最小占用时间的方法

通过用动态规划给出化学反应器序列最小占用时间的设计方法,提出了一个过程的最优化输出设计,该设计在输出产品浓度给定的条件下建立问题的基本设计量和数学模型,利用动态规划原则确定各阶段的占用时间,使总的占用时间为最小值,能够合理的确定各阶段反应器的体积以取得较好的经济效应.图3,表1,参8.     

具有时滞的非自治的Lotka-Volterra生态系统的全局稳定性

考虑一个具有时滞的非自治的捕食——食饵生态系统。该系统是由一个捕食，二个食饵种群所构成我们给出了系统的周期解是全局稳定的充分条件。