FURTHER RESULTS ON THE EXISTENCE OF PERIODIC SOLUTIONS TO DDES WITH MULTIPLE LAGS

1.IntroductionInthispaperwedealwiththeexistenceofperiodicsolutionstothedifferential-delayequations(DDEs)oftheformwherewesupposeinwhatfollowsthatexist.(itisallowedthatshouldbeincreasing.)WehaveLemmaSuppose(H)holdsandn1isaninteger.Ifthereexistsanintege...     

多变时滞 n 阶非线性中立型泛函微分方程周期解存在性

该文利用重合度理论,研究多变时滞 n 阶非线性中立型泛函微分 方程周期解存在性,给出这类方程存在周期解的一个较一般的判别法与四个充分性定理.     

对技术进步贡献率“索洛余值法”估计的一种改进

在用"索洛余值法"估计技术进步贡献率研究的基础上,将多项式分布滞后模型和半参数回归模型引入"索洛方程",对"索洛余值法"估计进行改进,避免前提假设未得到满足而直接对参数进行估计,并以山西省为例进行实证分析.     

Time-Optimal Control of Infinite Order Distributed Parabolic Systems Involving Multiple Time-Varying Lags

In this article, a time-optimal control problem for linear infinite order distributed parabolic systems involving multiple time-varying lags appearing both in the state equation and in the boundary condition is presented. Some particular properties of the optimal control are discussed.     

Moment exponential stability and integrability of stochastic functional differential equations

The main objective of the paper is to present sufficient conditions ensuring the pth mean and almost sure exponential stability, as well as the pth mean integrability of solutions to non-linear stochastic functional differential equations and, especially, to stochastic differential equations with time-varying lags. Some examples are given to illustrate the theoretical considerations.     

Mixed-integer linear programming for resource leveling problems

We consider project scheduling problems subject to general temporal constraints, where the utilization of a set of renewable resources has to be smoothed over a prescribed planning horizon. In particular, we consider the classical resource leveling problem, where the variation in resource utilization during project execution is to be minimized, and the so-called “overload problem”, where costs are incurred if a given resource-utilization threshold is exceeded. For both problems, we present new mixed-integer linear model formulations and domain-reducing preprocessing techniques. In order to strengthen the models, lower and upper bounds for resource requirements at particular points in time, as well as effective cutting planes, are outlined. We use CPLEX 12.1 to solve medium-scale instances, as well as instances of the well-known test set devised by Kolisch et al. (1999). Instances with up to 50 activities and tight project deadlines are solved to optimality for the first time.     

双时间尺度湍流模型的应用

双时间尺度湍流模型的应用蔡晓丹，陈义良（中国科技大学工程热物理系合肥２３００２６）关键词：双时间尺度，湍流模型一、引言流动的分离现象是自然界最常见的现象之一。在工程应用中，对流动分离的控制往往是我们关心的焦点。二维后台阶流动（图正），是一种典型的有回...     

An optimization problem for time lag distributed parabolic systems

We consider an optimal boundary control problem for a distributed parabolic system with boundary conditions involving multipletime-varying lags. Necessary and sufficient optimality conditionsfor the Neumann problem with the quadratic performance functionalsare derived. The results are illustrated with numerical solutionsof example tasks.     

协调多时次差分格式的数值试验

在一个简化气候模式的混沌态上，针对影响实际预报准确度的多种因素，将协调多时次差分 格式与提为时间演变的变分同化进行了全面的比较.结果发现协调多时次差分格式可以有效 地纠正模式误差，尤为独特之处在于其还可以有效地纠正微分方程本身不完善所造成的误差 ，而这一点正是变分同化所不及的. 关键词： 协调多时次差分格式 变分同化 全局数值试验 混沌     

自忆模式中差分格式的稳定性研究

基于大气运动是一种不可逆过程的观点，引进了忆及过去时次资料的记忆函数，导出热传导的自忆性方程，研究了方程分别取Richardson和DuFort-Frankel格式，回溯阶p取1时的稳定性.探讨了多时刻模式中数值积分有时发散的问题，揭示了由过去时次资料动态求取记忆函数，改变了原定设计的差分格式，且它是一个时间平滑因子的本质. 关键词： 回溯阶差分格式 多时次 稳定性 记忆性