华北平原区典型下垫面退水过程研究

以位于邯郸永年区的河北工程大学降雨-径流-灌排试验场为依托,进行数场人工模拟降雨试验,分别探讨了华北平原区典型下垫面河道径流、地表径流和各层壤中流出流的退水特征。对各种出流方式对比结果表明, 河道径流和地表径流在降雨停止后迅速消退,且很快退水完毕;壤中流退水往往在地表径流退水的后半程开始,其退水历时最长, 流量最小。影响因子分析表明, 降雨强度对退水流量的影响比较明显地表现在河道径流方面,即随降雨强度的加大,河道径流的退水流量呈幂函数上升趋势;降雨量对各层壤中流总退水流量的影响显著,即随着降雨量的增大,壤中流退水流量呈幂函数增大趋势;降雨历时对各种方式的退水流量影响均不明显。雨强还影响退水流量在总径流量中的分配比例,河道径流、地表径流、壤中流1和和壤中流2出流的退水流量分别占总流量的0.72%、8.6%、1.71%和0.19%,退水流量占总流量的12.31%。当雨强小于2mm/min时,随着雨强的增大地表径流退水流量所占比例呈直线增加趋势,但当雨强增加到2mm/min以上之后,地表径流退水流量所占比例反而下降了;随着雨强的增加,壤中流总退水流量所占比例呈对数函数逐渐下降的趋势。计算结果表明, 该区退水常数可以分河道径流、地表径流退水和壤中流退水2类, 其数次降雨平均值分别为 0.85 和 0.95。这一结果为进一步研究水文过程乃至流域尺度的退水过程提供了借鉴。     

Semicoercive variational hemivariational inequalities

The aim of this paper is the mathematical study of a general class of semicoercive variational hemivariational inequalities introduced by P.D. Panagiotopoulos in order to formulate problems of mechanics involving nonconvex and nonsmooth energy function. Our approach is based on the asymptotic behavior of the functions which are involved in the variational problems.     

Weighting factor results in vector optimization

This paper deals with the study, in a convex vector optimization problem, of the set of efficient solutions and the set of properly efficient solutions, the latter being obtained by a weighting factor technique. Relationships between these two sets are discussed; they are shown to be nonempty when the objective functions have no common direction of recession and to be closed and equal when, moreover, the objective functions are locally polyhedral. An example is provided where the set of efficient solutions is not included in the closure of the nonempty set of properly efficient solutions.The author wishes to thank the unknown referee for the helpful comments that improved the quality of this paper.     

Solvability Theory and Projection Methods for a Class of Singular Variational Inequalities: Elastostatic Unilateral Contact Applications

The mathematical modeling of engineering structures containing members capable of transmitting only certain type of stresses or subjected to noninterpenetration conditions along their boundaries leads generally to variational inequalities of the form , where C is a closed convex set of (kinematically admissible set), (loading strain vector), and (stiffness matrix). If rigid body displacements and rotations cannot be excluded from these applications, then the resulting matrix M is singular and serious mathematical difficulties occur. The aim of this paper is to discuss the existence and the numerical computation of the solutions of problem (P) for the class of cocoercive matrices. Our theoretical results are applied to two concrete engineering problems: the unilateral cantilever problem and the elastic stamp problem.     

Primal and Dual Stability Results for Variational Inequalities

The purpose of this paper is to study the continuous dependence of solutions of variational inequalities with respect to perturbations of the data that are maximal monotone operators and closed convex functions. The constraint sets are defined by a finite number of linear equalities and non linear convex inequalities. Primal and dual stability results are given, extending the classical ones for optimization problems.     

桓仁水库汛限水位动态控制决策支持表研制

针对水库汛限水位动态控制方案的具体化和可操作性问题,依据水库调洪计算原理和流域水量平衡原理,研制了桓仁水库汛限水位动态控制决策支持表.由此套表,即可根据实时和预报的水雨工情信息,确定面临时刻允许控制的库水位值及控泄流量等,方便水库调度技术人员和决策人快速查算、决策.该研究方法可供我国调节性能较高的大型水库(水电站)汛期洪水退水段库水位实时控制借鉴参考.     

Norm-closure of the barrier cone in normed linear spaces

The aim of this note is to characterize the norm-closure of the barrier cone of a closed convex set in an arbitrary normed linear space by means of a new geometric object, the temperate cone.

     

产业衰退期中企业退出的博弈模型分析

重点研究了采用博彝模型的方法产业衰退期间企业的市场退出战略行为．完全信息静态博弈研究的结论是,如果认为产业的衰退是短暂的,企业很可能选择留在行业里．反之,如果企业的决策者认为产业的衰退是长期的,则企业都会选择退出．而消耗战与企业退出博弈分析蛄论是,在产业的衰退期,企业为了争取留下来获得相应的利润而进行一场消耗战,最终失败的企业退出产业,胜利者留下来．     

Existence of Global Minima for Constrained Optimization

We present a unified approach to establishing the existence of global minima of a (non)convex constrained optimization problem. Our results unify and generalize previous existence results for convex and nonconvex programs, including the Frank-Wolfe theorem, and for (quasi) convex quadratically constrained quadratic programs and convex polynomial programs. For example, instead of requiring the objective/constraint functions to be constant along certain recession directions, we only require them to linearly recede along these directions. Instead of requiring the objective/constraint functions to be convex polynomials, we only require the objective function to be a (quasi)convex polynomial over a polyhedral set and the constraint functions to be convex polynomials or the composition of coercive functions with linear mappings.We thank Professor Dimitri Bertsekas for his comments and support in the writing of this paper.     

一类集值映射的连续性

基于对拟线性函数的深入研究，利用凸集分离定理和回收锥的性质，对由 Rn上拟线性函数构成的参数约束集，给出了在 Berge意义下当参数变化时，约束集产生的映射是下半连续的一个重要结论.利用该结论，可以很方便地得出拟线性规划稳定性的一系列结果.