积分微分系统的鲁棒稳定化

研究了具有时滞的积分微分系统的鲁棒稳定化问题，利用不等式分析技巧，给出了具有不确定系统的鲁捧全局一致渐近稳定性的判别准则，举例说明了文中结果的优越性。     

误差补偿和时滞辨识预测控制算法

通过神经网络辨别出非线性系统的滞后时间,并采用误差补偿手段对神经网络进行修正,控制系统的反馈取自不带时滞的非线性神经网络的输出,采用预测控制策略改善整个系统的控制性能。仿真实验表明该方法具有较快的响应速度和较强的自适应性与鲁棒性,能有效克服延迟和干扰给控制品质带来的不利影响,取得了良好的控制性能。     

关于Bellman問題

本文首先研究了常时滞线性方程与变时滞线性方程解之间的一致性问题,然后作为特殊情况,解决了Bellman于1965年提出的一个问题。     

Dynamic sampling plans in on-line control charts

Three simple dynamic sampling plans for detecting the change point are investigated in the discrete-time case. The first is a two-rate sampling CUSUM procedure. The second is a two-rate sampling Shiryayev-Roberts procedure. The third is a periodic sequential testing procedure. Two problems are discussed. First, simple design methods are provided for practical use. Second, a comparison between the three plans is made in the continuous-time case, which shows that by properly choosing the design parameters, the three plans can be made equally efficient in certain senses.     

含时滞的单种群反馈控制扩散模型解的渐近行为

本文通过构造 Liapunov 泛函并结合 Smoller 不变区域理论和不等式估计方法,对含时滞的单种群反馈控制扩散模型解的渐近行为进行了讨论,获得了解的整体存在性、有界性及解的一致收敛性的若干充分条件.     

DELAY ESTIMATION BY A HILBERT TRANSFORM METHOD

This paper describes an estimation of the time delay between two stationary time series signals, in which an input signal is measured with little noise and an output signal is the sum of a noise and the response from a linear system. We use the Hilbert transform relation for minimum delay systems to estimate the time delay. Some computer simulation results are given to evaluate the performance of the proposed method.     

“The Motherhood Wage Gap for Women in the United States: The Importance of College and Fertility Delay”

One of the stylized facts from the past 30 years has been the declining rate of first births before age 30 for all women and the increase rate of first births after age 30 among women with four-year college degrees (Steven P. Martin, Demography, 37(4), 523–533, 2000). What are some of the factors behind womens decision to postpone their childbearing? We hypothesize that the wage difference often observed between like-educated mothers and non-mothers (Jane Waldfogel, Journal of Labor Economics, 16, 505–545, 1998a; Journal of Economic Perspectives 12(1) 137–156, 1998b) may be affected by the postponement of childbearing until after careers are fully established. Hence, we focus on college-educated women because they are typically more career-oriented than their non-college educated counterparts and also the group most often observed postponing maternity. We use individual-level data on women from the 1979 National Longitudinal Survey of Youth (NLSY79) in order to control for individual-level unobserved heterogeneity as well as human capital characteristics, such as actual work experience, in our empirical analysis. We estimate wage equations, first producing base-line results to compare to the existing literature. Then, we expand the basic wage equation model to address fundamental econometric issues and the education/fertility issue at hand. Our empirical findings are two-fold. First, we find that college-educated mothers do not experience a motherhood wage penalty at all. In fact, they enjoy a wage boost when compared to college-educated childless women. Second, fertility delay enhances this wage boost even further. Our results provide an explanation for the observed postponement of maternity for educated women. We argue that the wage boost experienced by college-educated mothers may be the result of their search for family–friendly work environments, which, in turn, yields job matches with more female-friendly firms offering greater opportunities for advancement.JEL Codes: J13 and J3     

A STOCHASTIC LOGISTIC MODEL WITH TIME DELAY

The stochastic version of the logistic model for population growth is generalized to take account of continuously distributed time delay with an exponentially decaying kernel. The theory of diffusion processes is used to analyse the probability density function of the population size. The explicit expression for the stationary distribution is worked out and the effect of time delay on various statistics is discussed.     

一类推广的Halanay不等式的稳定性研究及其应用

利用Halanay不等式的推广形式,证明了一类时滞微分系统的指数稳定性,得到了一个新的积分条件,推广和改进了已有的结果,并结合例子加以说明.     

Impulsivity as a Risk Factor for HIV Transmission in Men Who Have Sex with Men: A Delay Discounting Approach

Delay discounting (DD) is a measure of impulsivity that describes the subjective decline in value of a consequence as the delay to that consequence increases. We sought to assess whether the results of a monetary DD task would be predictive of sexual risk-taking in a group of Internet-using men who have sex with men (MSM). 1402 participants completed an online survey that included questions about the participant’s demographics, sexual history and behavior, drug use, sexual compulsivity, and a monetary DD task. High DD was associated with increased odds of reporting >2 UAI partners in the past 12 months [aOR = 1.5 (1.1–2.1)]. Future studies should examine the utility of DD as a predictor of risky sexual behavior, as well as explore the possibility of HIV prevention interventions targeting DD.