不确定理论下的DC型养老金的最优投资策略问题

在不确定理论的框架下,研究确定缴费(DC)型养老金的最优投资策略问题.以最小化二次损失函数为目标,分别在固定缴费和不确定缴费的情形下,建立养老金的最优化模型.利用不确定动态规划法,证明了不确定最优性原理,得出了不确定最优性方程,通过求解不确定最优性方程得到最优给付率和最优投资策略.     

具有随机投资收益的离散风险模型的最优红利分配

本文讨论的是离散模型下以期望累计红利最大化为目标的最优红利分配政策,通过Bellman最优性准则,我们得到了最优值函数满足的动态规划方程并结合实例给出了求解这些方程的算法.     

基于相依风险模型框架均值方差准则下的最优时间一致的投资再保险策略问题（英文）

本文研究了在相依风险模型的框架下保险公司的最优投资和再保险问题.在均值方差准则下,利用博弈论的相关理论,求解扩展的HJB方程系统,得到最优时间一致的投资和再保险策略以及相应的最优值函数,并通过数值例子展现模型参数对最优策略的影响。     

考虑模型不确定的TBP养老金的鲁棒最优投资策略研究

以目标收益养老金计划(TBP)模型研究鲁棒最优投资问题, 其中养老金管理者对模型参数不确定带来的风险是模糊风险厌恶的. 养老金管理者为规避风险和增加收益将投资于无风险资产和风险资产. 考虑连续时间情形, 假设养老金计划参保人的缴费是确定的, 而参保人的收益给付是确定目标收益给付, 资金账户的收益风险由不同代际的参保人共同承担, 同时考虑随机工资及其与金融市场的相关性. 以参保人退休后养老金给付偏离目标的风险和代际之间风险分担的组合最小化为投资决策目标, 并采用指数函数的形式描述实际给付与目标给付的偏离, 利用随机最优控制方法, 建立相应的HJB方程并求解得到最优投资收益策略和最优给付策略的解析解. 通过数值示例分析了模型参数对最优投资和最优给付策略的影响.     

基于Hurwicz准则的不确定养老金最优投资策略问题

本文提出一种新的养老金最优投资策略模型,研究了带有不确定工资过程的DC型养老金最优投资策略问题.以二次损失函数的Hurwicz加权平均值最小化为目标,针对两类相对财富过程,给出了养老金最优投资策略的显式表达式.最后,通过数值分析,研究了模型参数对最优投资策略的影响.     

Ornstein-Uhlenbeck模型下DC养老金计划的最优投资策略

本文研究了Ornstein-Uhlenbeck模型下确定缴费型养老金计划(简称DC计划)的最优投资策略,其中以最大化DC计划参与者终端财富(退休时其账户金额)的CRRA效用为目标.假定投资者可投资于无风险资产和一种风险资产,风险资产的瞬时收益率由Ornstein-Uhlenbeck过程驱动,该过程能反映市场所处的状态.利用随机控制理论,给出了相应的HJB方程与验证定理;并通过求解相应的HJB方程,得到了最优投资策略和最优值函数的解析式.最后分析了瞬时收益率对最优投资策略的影响,发现当市场向良性状态发展时,投资在风险资产上的财富比例呈上升趋势;当初始财富足够大且市场状态不变时,投资在风险资产上的财富比例几乎不受时间的影响.     

马尔可夫机制转换模型下确定缴费型养老金计划的最优投资策略

研究了马尔可夫机制转换模型下确定缴费型养老金计划的最优投资问题.假定市场中风险资产价格与企业员工的工资都满足马尔可夫调制的几何布朗运动模型,它们的预期回报率和波动率都依赖于市场经济状态,其经济状态由一连续时间马尔可夫链来描述.利用最终财富的最大期望效用准则,得到了养老金管理者的最优投资策略,结果表明市场的经济状态对最优投资策略有着很大的影响.最后通过数值计算分析了市场利率和绝对风险厌恶系数与最优投资策略的关系.     

基于注资-阀值分红的随机微分投资-再保博弈

为了更好地反映模型风险对保险公司金融策略的影响,考虑了存在模型风险时,保险公司的最优投资-再保-注资-阀值分红策略问题.在分红与注资总量的贴现值之差的期望最大化的准则下,使用零和随机微分博弈理论建立了保险公司的随机微分博弈模型,通过求解HJBI方程得到了最优投资-再保-注资-阀值分红策略的显式解.最后在有模型风险和无模型风险两种不同情形下,通过数值算例分析了保险公司金融策略之间的差异,为保险资金的管理提供了重要的决策指导.     

通胀风险与波动风险环境下带有保费返还条款的DC型养老金计划

通胀风险和波动风险是影响养老金计划的最重要的两个因素,保费返还条款可以保障死亡的养老基金持有者的权益.文章研究了通胀风险和波动风险环境下带有保费返还条款的确定缴费型(DC型)养老金计划问题.模型中假设风险资产价格由Heston随机波动率模型驱动,养老金被允许投资于一种无风险资产、一种风险资产和一种通胀相关指数债券.在均值-方差准则下,利用随机控制理论、博弈论和变量分离法得到了时间一致最优投资策略和有效前沿的显性解.最后通过应用数值算例对最优投资策略和有效前沿进行了敏感性分析.     

跳—扩散过程下带实业项目的保险最优决策

为了考虑一类带有实业项目投资的保险最优投资策略问题,假定保险公司盈余服从跳-扩散过程,在最小化保险公司破产概率准则下,使用动态规划原理建立了线性消费率下保险资金最优投资选择模型,通过求解HJB方程得到了最优投资决策和最小破产概率的解析式解,最后分析了线性消费、索赔强度、索赔额以及实业项目投资额对最小化破产概率和最优投资策略的影响.     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Generalization of the interaction between Haar approximation and polynomial operators to higher order methods

In applications it is useful to compute the local average empirical statistics on u. A very simple relation exists when of a function f（u） of an input u from the local averages are given by a Haar approximation. The question is to know if it holds for higher order approximation methods. To do so, it is necessary to use approximate product operators defined over linear approximation spaces. These products are characterized by a Strang and Fix like condition. An explicit construction of these product operators is exhibited for piecewise polynomial functions, using Hermite interpolation. The averaging relation which holds for the Haar approximation is then recovered when the product is defined by a two point Hermite interpolation.     

Jacobi polynomials used to invert the laplace transform

Given the Laplace transform F(s) of a function f(t), we develop a new algorithm to find an approximation to f(t) by the use of the classical Jacobi polynomials. The main contribution of our work is the development of a new and very effective method to determine the coefficients in the finite series expansion that approximation f(t) in terms of Jacobi polynomials. Some numerical examples are illustrated.