SOME PROPERTIES OF SOLUTIONS OF ONE-DIMENSIONAL STOCHASTIC DIFFERENTIAL EQUATIONS WITH GENERAL COEFFICIENTS

In this paper, the one-dimensional time-homogenuous lto’s stochastic differential equations, which have degenerate and discontinuous diffusion coefficients, are considered. The non-confluent property of solutions is showed under some local integrability condition on the diffusion and drift coefficients. The strong comparison theorem for solutions is also established.

Stability of Neutral Stochastic Differential Equations with Multiple Variable Delays

This paper discusses the pth moment stability of neutral stochastic differential equations with multiple variable delays. The equation has a much more general form than the neutral stochastic differential equations with delay. A new kind of φ-function is introduced to address the stability, which is more general than the exponential stability and polynomial stability. Using a specific Lyapunov function, a stability criteria for the neutral stochastic differential equations with multiple variable delays is established, by which it is relatively easy to verify the stability of such equations. Finally, the proposed theories are illustrated by two examples.

Modeling Election Problem by a Stochastic Differential Equation

The proportion of the favorable among voters to a nominee might change over times and depend on different factors for example: talent, reputation, party and even name order on election. The unobservable factors which might have minor impacts on the approval rate are modelized by random elements. The approval rate is initially described by the differential equation and then by the random differential equation including the above unobservable factors. We figure out the formula of the solution for the stochastic differential equation and simulate these solutions to identify the changes of the approval rate over time.

ASYMPTOTIC STABILITIES OF STOCHASTIC FUNCTIONAL DIFFERENTIAL EQUATIONS

Asymptotic characteristic of solution of the stochastic functional differential equation was discussed and sufficient condition was established by multiple Lyapunov functions for locating the limit set of the solution. Moreover, from them many effective criteria on stochastic asymptotic stability, which enable us to construct the Lyapunov functions much more easily in application, were obtained, The results show that the wellknown classical theorem on stochastic asymptotic stability is a special case of our more general results. In the end, application in stochastic Hopfield neural networks is given to verify our results.

Stochastic Dynamics of Cholera Epidemic Model: Formulation, Analysis and Numerical Simulation

In this paper, we describe the two different stochastic differential equations representing cholera dynamics. The first stochastic differential equation is formulated by introducing the stochasticity to deterministic model by parametric perturbation technique which is a standard technique in stochastic modeling and the second stochastic differential equation is formulated using transition probabilities. We analyse a stochastic model using suitable Lyapunov function and Itôformula. We state and prove the conditions for global existence, uniqueness of positive solutions, stochastic boundedness, global stability in probability, moment exponential stability, and almost sure convergence. We also carry out numerical simulation using Euler-Maruyama scheme to simulate the sample paths of stochastic differential equations. Our results show that the sample paths are continuous but not differentiable (a property of Wiener process). Also, we compare the numerical simulation results for deterministic and stochastic models. We find that the sample path of SIsIaR-B stochastic differential equations model fluctuates within the solution of the SIsIaR-B ordinary differential equation model. Furthermore, we use extended Kalman filter to estimate the model compartments (states), we find that the state estimates fit the measurements. Maximum likelihood estimation method for estimating the model parameters is also discussed.

A 1-Dimensional Nonlinear Filtering Problem

We will concentrate on a 1-dimensional nonlinear filtering problem, which allows an explicit solution in terms of a stochastic differential equation for Xt.

Proof of Ito’s Formula for Ito’s Process in Nonstandard Analysis

In our previous paper [1], we proposed a non-standardization of the concept of convolution in order to construct an extended Wiener measure using nonstandard analysis by E. Nelson [2]. In this paper, we consider Ito’s integral with respect to the extended Wiener measure and extend Ito’s formula for Ito’s process. Because of doing the extension of Ito’s formula, we could treat stochastic differential equations in the sense of nonstandard analysis. In this framework, we need the nonstandardization of convolution again. It was not yet proved in the last paper, therefore we shall provide the proof.

Comparison principle and stability criteria for stochastic differential delay equations with Markovian switching

In the present paper we first obtain the comparison principle for the nonlinear stochastic differentialdelay equations with Markovian switching. Later, using this comparison principle, we obtain some stabilitycriteria, including stability in probability, asymptotic stability in probability, stability in the pth mean, asymptoticstability in the pth mean and the pth moment exponential stability of such equations. Finally, an example isgiven to illustrate the effectiveness of our results.

EXPONENTIAL ESTIMATE OF SOLUTION TO STOCHASTIC FUNCTIONAL DIFFERENTIAL EQUATIONS WITH INFINITE DELAY

In this paper, by the Burkholder-Davis-Gundy inequality and It? formula, the exponential estimate of the solution to stochastic functional differential equations with infinite delay is established in the phase space BC((-∞,0];Rd). Furthermore, the sample Lyapunov exponent of the solution is obtained, which is less than a positive constant 2√K + 65K. Moreover, a pth moment of the solution is studied.

Ito积分和Stratonovich积分的比较(英文)

引入了It积分和Stratonovich积分的定义,介绍了计算It积分的It公式,并讨论了It积分和Stratonovich积分之间的关联公式。通过实例,运用这两种积分分别求解随机微分方程,并将结果进行了对比。最后,对它们在不同的实际应用中各自具有的优、缺点进行了讨论。

The Cauchy problem of Backward Stochastic Super-Parabolic Equations with Quadratic Growth

The paper is devoted to the Cauchy problem of backward stochastic superparabolic equations with quadratic growth.We prove two Ito formulas in the whole space.Furthermore,we prove the existence of weak solutions for the case of onedimensional state space,and the uniqueness of weak solutions without constraint on the state space.

一类非Lipschitz条件的BSDE解的存在唯一性

本文讨论了倒向随机微分方程在f(t,y,z)满足:(?)N>0,(?)CN0,LN>0,使得对任意y1,y2∈Rn,z1,z2∈Rn×d 当0≤|y1|,|y2|,|z1|,|z2|≤N时,有 |f,(s,y1,z1)-f(s,y2,z2)|2≤CNK(t,|y1-y2|2)+LN|z1-z2|2 的非Lipschitz条件时解的存在性和唯一性。2003年,王赢、王向荣证明了一类倒向随机微分方程解的存在唯一性,我们使用函数逼近法,得到一列满足王赢,王向荣文中条件的倒向随机微分方程,因而每个方程均有唯一解,然后通过取极限的方法证明我们所讨论的方程有唯一解(Y Z),从而推广了他们的结果。

关于系数平方增长的带跳BSDE的解(Ⅰ)

讨论了系数关于q为平方增长,p和-y为指数增长的带跳倒向随机微分方程(BSDE)解的存在性,以及有这种系数的反射BSDE解的存在性。

随机比例微分方程的LaSalle-型定理

建立随机比例方程解析解的LaSalle-型渐进收敛定理,据此得到随机比例方程解析解渐进稳定的条件,给出一个例子.

弹性杆具有随机力的Schrdinger方程(英文)

给出了一种用随机分布力来刻画液体分子对DNA分子的作用的模型。得到了随机Schrdinger方程。给出了上述方程的一阶算法,并且给出了数值例子。模拟了DNA分子受到随机力的作用时的中心线形态。

Extended Wiener Process in Nonstandard Analysis

Standing on a different view point from Anderson, we prove that the extended Wiener process defined by Anderson satisfies the definition of the Wiener process in standard analysis, for example the Wiener process at time t obeys the normal distribution N(0,t) by showing the central limit theorem. The essential theory used in the proof is the extended convolution property in nonstandard analysis which is shown by Kanagawa, Nishiyama and Tchizawa (2018). When processing the extension by non-standardization, we have already pointed out that it is needed to proceed the second extension for the convolution, not only to do the first extension for the delta function. In Section 2, we shall introduce again the extended convolution as preliminaries described in our previous paper. In Section 3, we shall provide the extended stochastic process using a hyper number N, and it satisfies the conditions being Wiener process. In Section 4, we shall give a new proof for the non-differentiability in the Wiener process.

非Lipschitz条件下带扰动倒向随机微分方程的比较定理

对带扰动的倒向随机微分方程进行了研究,利用Gronwall不等式,Jensen不等式,以及常微分方程的比较定理,给出了一类非Lipschitz条件下带扰动的倒向随机微分方程解的比较定理.

基于投资理论的保险定价公式

在保险公司是风险中性的假设下 ,运用倒向随机微分方程的理论 ,研究了保险公司在风险投资框架下的保险定价问题。首先 ,建立了保险定价问题的线性正倒向随机微分方程数学模型 ;然后 ,根据一类特殊线性倒向随机微分方程的显式解 ,推出了由风险投资确定的保险定价公式 ;最后 ,进行了算例分析。

一类中立型随机泛函微分方程的稳定性分析

研究了一类中立型随机泛函微分方程的p阶矩稳定性和几乎必然稳定性.借助于It公式、Fatou引理、局部鞅收敛定理和不等式分析技巧,得到了中立型随机泛函微分方程的p阶矩稳定和几乎必然稳定的充分条件,其结论更具有一般性.

多维带跳倒向双重随机微分方程解的性质

本文研究一类多维带跳倒向双重随机微分方程,给出了It(?)公式在带跳倒向双重随机积分情形下的推广形式,同时运用推广形式的It(?)公式,在Lipschitz条件下证明了方程解的存在性和唯一性。