多变时滞中立型系统稳定性研究

本文研究了一类多时变时滞中立型系统的渐近稳定性问题。基于Lyapunov第二方法,推导出新的时滞依赖稳定性判据。所给得判据可以保证多变时滞中立型系统渐进稳定,结论以线性矩阵不等式(LMI)形式表示,便于应用。仿真结果表明本文稳定性判定准则具有较小的保守性。     

一种基于传播时延修正的网络时间互同步算法

介绍了一种时间互同步算法的基本原理,并通过仿真试验分析了该算法在不同环境下的性能,指出其应用在地理覆盖范围较大的网络中的局限性。为改善该算法在实际应用场景中的性能,提出了一种基于传播时延修正的新策略。仿真结果表明,改进后的时间同步算法在传播时延不能忽略的场景中的性能远远优于原来的算法,其同步精度由原算法的1 ms左右提高到几微秒到几十微秒的量级,在实际工程中具有较高的应用价值。     

中外黄金市场混沌特性比较——基于相空间重构技术

运用相空间重构技术,分别对上海黄金交易所和伦敦黄金交易市场的现货黄金价格时间序列进行相空间重构,运用互信息法计算嵌入延迟,运用Cao方法计算嵌入维数,运用小数据量法计算最大Lya-punov指数,运用G-P算法估算关联维数和Kolmogorov熵,得出上海黄金市场具有混沌和分形特征的结论。进而对两系统的混沌特性、有效价格预测时间尺度等进行比较,发现两市场整体的混沌程度相当,其中上海黄金市场的复杂度小于伦敦黄金市场,但其价格波动的发散性更强、最大可预测时间更短。最后指出,形成此差异的原因可能是上海黄金交易所是一个次要市场,其价格形成机制不同于作为主要市场的伦敦黄金市场。     

Factors Causing Design Schedule Delays in Turnkey Projects in Taiwan: An Empirical Study of Power Distribution Substation Projects

Because of its benefits, the turnkey project delivery method has received much global attention; however, turnkey contractors often have difficulty completing projects within the contract schedule. Through case studies, expert interviews, questionnaire surveys, and statistical data analysis, this study revealed that, of 27 delay factors that affect design schedules in power distribution substation projects, the most common delay factors are “public contending or political involvement” and “tedious review processes of government agencies.” Furthermore, the study proposes assorted strategies from the perspectives of the owner, turnkey contractor, and designer that can be used to help prevent delays in similar turnkey projects.     

带有短缺量拖后率的时滞变质品库存模型研究

文章对时滞变质物品的库存模型进行了研究。假设允许缺货且短缺量拖后率为指数函数,通过建立库存模型分析变质品在缺货时点发生在变质期前和变质期后的总成本,最后,给出了数值算例对模型进行阐释。研究结果表明:缺货时点发生在变质期前的库存成本比发生在变质期后小。     

加性白噪声下基带延迟锁定环跟踪精度的计算

研究了加性白噪声下基带延迟锁定环跟踪精度的计算问题,着重讨论了积分时间和 环路带宽的关系。以码延迟相关鉴别器的等效鉴相模型为基础,研究了相关器输出噪声特性 及其在输入端等效噪声的特性,推导了线性跟踪环输出噪声方差的计算公式,并得到了积分 时间和环路带宽分别起主导作用时的简化计算公式,使两种不同的结论得到了统一。     

基于局域网的实时语音通信时延研究

在局域网中语音通信时延是影响语音质量的重要因素。为了最大限度地降低局域网中语音通信时延,提高语音质量,以采用低阶音频函数和UDP协议实现语音传输系统为基础,通过实验并分析了造成局域网中语音通信时延的主要因素,提出了在局域网中最大限度地降低实时语音通信时延的解决策略,实验数据证明,时延的分析是正确的,降低时延的策略是有效的。     

Access pricing and investment: a real options approach

This paper examines a three-period model of an investment decision in a network industry characterized by demand uncertainty, economies of scale and sunk costs. In the absence of regulation we identify the market conditions under which a monopolist decides to invest early as well as the overall welfare generated by this decision. In a regulated environment, we consider a vertically integrated network provider that is required to provide access to downstream competitors and compare two distinct access pricing methodologies: the Efficient Component Pricing Rule (ECPR) and the Option to Delay Pricing Rule (ODPR). We identify the welfare-maximizing access prices using the unregulated market output as a benchmark and show that optimal access regulation depends on market conditions (that is, the nature of demand) with two possible outcomes: (i) access prices that provide a positive payoff to the incumbent, that is, provide a positive compensation to account for the option to delay; and (ii) access prices that yield a zero payoff to the incumbent. Moreover, unlike the earlier literature that argues in favor of an ECPR-type methodology to account for the interaction between irreversibility and demand uncertainty, we find that, except under very specific conditions, an access price that accounts for the option to delay value is welfare-superior to the ECPR.      

Optimal pricing and ordering policy for deteriorating inventory under trade credit in demand declining market

In market, the retailer tries to sell the product at much higher price than the purchase cost. In this study, an attempt is made to develop optimal ordering and pricing policy for a retailer when the supplier offers a credit period to settle the account. The demand of a product is declining with time and units in the retailer＇s inventory are subject to constant deterioration. An algorithm is developed to determine the optimal selling price and the ordering quantity to maximize the retailer＇s profit. The numerical examples are given to support the development of the mathematical model. The sensitivity analysis of critical parameters is carried out to observe the changes in the decision variables and objective function.     

3种移动闭塞模式下列车延迟传播规律的研究

介绍了移动空间闭塞、移动时间闭塞、完全移动闭塞3种移动闭塞模式,模拟讨论了3种模式下的列车延迟传播现象及其规律。模拟结果表明,在相同的初始延迟时间下,完全移动闭塞模式晚点列车总数最少,总的列车晚点时间最小;移动空间闭塞模式晚点列车总数最多,总的列车晚点时间最大。