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1.
§1Introductionandresults A2-parameterGaussianprocess{Z(t,s);t,s≥0}iacalleda2-parameterfractional Wienerprocesswithorderα(0<α<1),ifZ(0,0)=0a.s.EZ(s,t)=0anditscovariance EZ(t1,s1)Z(t2,s2)={|t1|2α+|t2|2α-|t2-t1|2α}{|s1|2α+|s2|2α-|s2-s1|2α}/4.LetR=[x1,x2]×[y1,y2],DT={(x,y)∶0≤x,y≤bT,xy≤T}.Let0相似文献   

2.
方世祖 《数学研究》2002,35(3):303-308
讨论二参数平衡无后效随机事件流的基本性质,局部鞅性和各种二参数Markov性,并用比较简单的方法给出二参数平稳无后效随机事件流的母函数的一般形式。  相似文献   

3.
We consider the Euler scheme for stochastic differential equations with jumps, whose intensity might be infinite and the jump structure may depend on the position. This general type of SDE is explicitly given for Feller processes and a general convergence condition is presented.

In particular, the characteristic functions of the increments of the Euler scheme are calculated in terms of the symbol of the Feller process in a closed form. These increments are increments of Lévy processes and, thus, the Euler scheme can be used for simulation by applying standard techniques from Lévy processes.  相似文献   

4.
两参数齐次独立增量过程在原点的局部性质   总被引:2,自引:0,他引:2  
Adler曾经给出了两参数独立增量过程的特征函数的一般形式.本文对齐次情形给出了更具体的表达式,引进了累积量的概念.在此基础上,研究了比值X(s,t)/st在原点的分布,单调过程在原点的局部性质以及任意过程在原点的局部增长.由此得到了Brown单和不包含高斯分量的过程在原点的局部增长.  相似文献   

5.
A model of a series of price increments with jumps is constructed based on a linear stochastic differential equation with a Poisson component. Some estimates of unknown parameters of the model and SDE are obtained by using the method of moments. A statistical simulation algorithm for solving an SDE with a Poisson component in general form is proposed. Results of numerical experiments are given.  相似文献   

6.
We consider a general insurance risk model with extended flexibility under which claims arrive according to a point process with independent increments, their amounts may have any joint distribution and the premium income is accumulated following any non-decreasing, possibly discontinuous, real valued function. Point processes with independent increments are in general non-stationary, allowing for an arbitrary (possibly discontinuous) claim arrival cumulative intensity function which is appealing for insurance applications. Under these general assumptions, we derive a closed form expression for the joint distribution of the time to ruin and the deficit at ruin, which is remarkable, since as we show, it involves a new interesting class of what we call Appell–Hessenberg type functions. The latter are shown to coincide with the classical Appell polynomials in the Poisson case and to yield a new class of the so called Appell–Hessenberg factorial polynomials in the case of negative binomial claim arrivals. Corollaries of our main result generalize previous ruin formulas e.g. those obtained for the case of stationary Poisson claim arrivals.  相似文献   

7.
In this paper, we show that the moving average and series representations of fractional Brownian motion can be obtained using the spectral theory of vibrating strings. The representations are shown to be consequences of general theorems valid for a large class of second-order processes with stationary increments. Specifically, we use the 1–1 relation discovered by M.G. Krein between spectral measures of continuous second-order processes with stationary increments and differential equations describing the vibrations of a string with a certain length and mass distribution.  相似文献   

8.
A model of optimal accumulation of capital and portfolio choice over an infinite horizon in continuous time is formulated in which the vector process representing returns to investments isa general semimartingale. Methods of stochastic calculus and calculus of variations are used to obtain necessary and sufficient conditions for optimality involving martingale properties ofthe shadow price processes associated with alternative portfolio cum saving plans.The relationship between such conditions and portfolio equations is investigated.The results are appliedtospecial cases where the returns process has stationary independent increments and the utility function has the discounted relative risk aversion form  相似文献   

9.
crements The a.s. sample path properties for ι^p-valued Gaussian processes with stationary increments under some more general conditions are established.  相似文献   

10.
The general properties of compact subdifferentials (K-subdifferentials) for mappings of a segment to a locally convex space are studied. Different forms of the general theorem of finite increments and the mean value theorem for compact subdifferentials are considered in detail with closed and open estimates.  相似文献   

11.
A NOTE ON SAMPLE PATH PROPERTIES OF l~p-VALUED GAUSSIAN PROCESSES   总被引:3,自引:0,他引:3  
§ 1 Introduction and ResultsLet{Y(t) ,t≥ 0 }={Xk(t) ,t≥ 0 }∞k=1 be a sequence of independent Gaussian processeswith EXk(t) =0 and stationary incrementsσ2k(h) =E(Xk(t h) -Xk(t) ) 2 ,where through-outthis paper,σ2k(h) is assumed to be a non-decreasing continuous function foreach k≥ 1 .For p≥ 1 ,putσ(p,h) = ∞k=1σpk(h) 1 /p, (1 .1 )σ* (h) =maxk≥ 1 σk(h) , (1 .2 )σ~ (p,h) =σ(2 p/(2 -p) ,h) ,if 1≤ p <2 ,σ* (h) ,if p≥ 2 ,(1 .3)δpp =E|N(0 ,1 ) |p =2 p/2π∫∞0 x(p- 1 ) /2 e- …  相似文献   

12.
We present a general control variate method for simulating path dependent options under Lévy processes. It is based on fast numerical inversion of the cumulative distribution functions and exploits the strong correlation of the payoff of the original option and the payoff of a similar option under geometric Brownian motion. The method is applicable for all types of Lévy processes for which the probability density function of the increments is available in closed form. Numerical experiments confirm that our method achieves considerable variance reduction for different options and Lévy processes. We present the applications of our general approach for Asian, lookback and barrier options under variance gamma, normal inverse Gaussian, generalized hyperbolic and Meixner processes.  相似文献   

13.
A Markov risk model with two classes of insurance business is studied. In this model, the two classes of insurance business are independent. Each of the two independent claim number processes is the number of jumps of a Markov jump process from time 0 to t, whichever has not independent increments in general. An integral equation satisfied by the ruin probability is obtained and the bounds for the convergence rate of the ruin probability are given by using a generalized renewal technique.  相似文献   

14.
Veraverbeke’s (Stoch Proc Appl 5:27–37, 1977) theorem relates the tail of the distribution of the supremum of a random walk with negative drift to the tail of the distribution of its increments, or equivalently, the probability that a centered random walk with heavy-tail increments hits a moving linear boundary. We study similar problems for more general processes. In particular, we derive an analogue of Veraverbeke’s theorem for fractional integrated ARMA models without prehistoric influence, when the innovations have regularly varying tails. Furthermore, we prove some limit theorems for the trajectory of the process, conditionally on a large maximum. Those results are obtained by using a general scheme of proof which we present in some detail and should be of value in other related problems.  相似文献   

15.
16.
We study a Gibbs measure over Brownian motion with a pair potential which depends only on the increments. Assuming a particular form of this pair potential, we establish that in the infinite volume limit the Gibbs measure can be viewed as Brownian motion moving in a dynamic random environment. Thereby we are in a position to use the technique of Kipnis and Varadhan and to prove a functional central limit theorem.  相似文献   

17.
Classical Edgeworth expansions provide asymptotic correction terms to the Central Limit Theorem (CLT) up to an order that depends on the number of moments available. In this paper, we provide subsequent correction terms beyond those given by a standard Edgeworth expansion in the general case of regularly varying distributions with diverging moments (beyond the second). The subsequent terms can be expressed in a simple closed form in terms of certain special functions (Dawson’s integral and parabolic cylinder functions), and there are qualitative differences depending on whether the number of moments available is even, odd, or not an integer, and whether the distributions are symmetric or not. If the increments have an even number of moments, then additional logarithmic corrections must also be incorporated in the expansion parameter. An interesting feature of our correction terms for the CLT is that they become dominant outside the central region and blend naturally with known large-deviation asymptotics when these are applied formally to the spatial scales of the CLT.  相似文献   

18.
The quasi-likelihood estimator and the Bayesian type estimator of the volatility parameter are in general asymptotically mixed normal. In case the limit is normal, the asymptotic expansion was derived by Yoshida [28] as an application of the martingale expansion. The expansion for the asymptotically mixed normal distribution is then indispensable to develop the higher-order approximation and inference for the volatility. The classical approaches in limit theorems, where the limit is a process with independent increments or a simple mixture, do not work. We present asymptotic expansion of a martingale with asymptotically mixed normal distribution. The expansion formula is expressed by the adjoint of a random symbol with coefficients described by the Malliavin calculus, differently from the standard invariance principle. Applications to a quadratic form of a diffusion process (“realized volatility”) are discussed.  相似文献   

19.
引进了一类N参数Gauss过程,它具有比N参数Wiener过程更为一般的性质.给出了此类N参数Gauss过程的异常震动点集的定义,并且定义了此异常震动点集的Hausdorff维数.研究了此类过程的异常震动点集Hausdorff维数,给出了它的一个确切的表达式,从而获得了与Zacharie (2001)的有关两参数Wiener过程的类似的结果.考虑的参数点集是一般的超长方体.而不是Zacharie (2001)考虑的超正方体.在此更为一般的情况下,首先建立了文中引进的过程的Fernique不等式.利用此不等式和Slepian引理,证明了过程的Lévy连续模定理.Zacharie(2001)关于Hausdorff维数公式的证明依赖于两参数Wiener过程的独立增量性,而这里引进的过程不具有这种性质,因此,必须采用新的证明途径.  相似文献   

20.
The notion of stochastic processes with proportional increments is introduced. This notion is of general interest as indicated by its relationship with several stochastic processes, as counting processes, Lévy processes, and others, as well as martingales related with these processes. The focus of this article is on the motivation to introduce processes with proportional increments, as instigated by certain characteristics of stopping problems under weak information. We also study some general properties of such processes. These lead to new insights into the mechanism and characterization of Pascal processes. This again will motivate the introduction of more general f-increment processes as well as the analysis of their link with martingales. As a major application we solve the no-information version of the last-arrival problem   which was an open problem. Further applications deal with the impact of proportional increments on modelling investment problems, with a new proof of the 1/e1/e-law of best choice, and with other optimal stopping problems.  相似文献   

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