Alternating Direction Finite Volume Element Methods for Three-Dimensional Parabolic Equations

<正>This paper presents alternating direction finite volume element methods for three-dimensional parabolic partial differential equations and gives four computational schemes,one is analogous to Douglas finite difference scheme with second-order splitting error,the other two schemes have third-order splitting error,and the last one is an extended LOD scheme.The L~2 norm and H~1 semi-norm error estimates are obtained for the first scheme and second one,respectively.Finally,two numerical examples are provided to illustrate the efficiency and accuracy of the methods.     

A FRACTIONAL NONLINEAR EVOLUTIONARY DELAY SYSTEM DRIVEN BY A HEMI-VARIATIONAL INEQUALITY IN BANACH SPACES

This article deals with a new fractional nonlinear delay evolution system driven by a hemi-variational inequality in a Banach space.Utilizing the KKM theorem,a result concerned with the upper semicontinuity and measurability of the solution set of a hemivariational inequality is established.By using a fixed point theorem for a condensing setvalued map,the nonemptiness and compactness of the set of mild solutions are also obtained for such a system under mild conditions.Finally,an example is presented to illustrate our main results.     

LIMIT CYCLES FOR A CLASS OF NONPOLYNOMIAL PLANAR VECTOR FIELDS(II)

In this paper, the problem of limit cycles for a class of nonpolynomial planar vector felds is investigated. First, based on Liapunov method theory, we obtain some sufcient conditions for determining the origin as the critical point of such nonpolynomial planar vector felds to be the focus or center. Then, using Dulac criterion, we establish some sufcient conditions for the nonexistence of limit cycles of this nonpolynomial planar vector felds. And then, according to Hopf bifurcation theory, we analyze some sufcient conditions for bifurcating limit cycles from the origin. Finally, by transforming the nonpolynomial planar vector felds into the generalized Li′enard planar vector felds, we discuss the existence, uniqueness and stability of limit cycles for the former and latter planar vector felds. Some examples are also given to illustrate the efectiveness of our theoretical results.     

A Finite Difference Scheme for Blow-Up Solutions of Nonlinear Wave Equations

<正>We consider a finite difference scheme for a nonlinear wave equation,whose solutions may lose their smoothness in finite time,i.e.,blow up in finite time.In order to numerically reproduce blow-up solutions,we propose a rule for a time-stepping, which is a variant of what was successfully used in the case of nonlinear parabolic equations.A numerical blow-up time is defined and is proved to converge,under a certain hypothesis,to the real blow-up time as the grid size tends to zero.     

Reflected SPDEs Driven by Fractional Noises

In this paper,we study the stochastic partial differential equation with two reflecting smooth walls h^1 and h^2,driven by a fractional noise,which is fractional in time and white in space.The large deviation principle for the law of the solution to this equation,will be established through developing a classical method.Furthermore,we obtain the H?lder continuity of the solution.     

Maximum Likelihood Estimator of the Location Parameter under Moving Extremes Ranked Set Sampling Design

Cost effective sampling design is a problem of major concern in some experiments especially when the measurement of the characteristic of interest is costly or painful or time consuming.In the current paper,a modification of ranked set sampling(RSS)called moving extremes RSS(MERSS)is considered for the estimation of the location parameter for location family.A maximum likelihood estimator(MLE)of the location parameter for this family is studied and its properties are obtained.We prove that the MLE is an equivariant estimator under location transformation.In order to give more insight into the performance of MERSS with respect to(w.r.t.)simple random sampling(SRS),the asymptotic efficiency of the MLE using MERSS w.r.t.that using SRS is computed for some usual location distributions.The relative results show that the MLE using MERSS can be real competitors to the MLE using SRS.     

立体几何中的活跃分子——直角四面体

三条侧棱两两相互垂直的四面体是一种特殊的四面体,我们称之为直角四面体,它具有以下性质:(1)任何一条侧棱垂直另两个侧棱构成的平面;(2)三个侧面两两垂直;(3)顶点在底面上的射影是底面三角形的垂心等,立体几何中很重要的概念和定理.都能从这个直角四正面体中衍生,因此深入研究直角四面体,对于把握空间图形中直线和平面的关系,尤为重要.下面利用直角四面体的性质简解两道商考题.……     

Time variant multi-objective linear fractional interval-valued transportation problem

This paper studies a time-variant multi-objective linear fractional transportation problem. In reality, transported goods should reach in destinations within a specific time. Considering the importance of time, a time-variant multi-objective linear fractional transportation problem is formulated here. We take into account the parameters as cost, supply and demand are interval valued that involved in the proposed model, so we treat the model as a multi-objective linear fractional interval transportation problem. To solve the formulated model, we first convert it into a deterministic form using a new transformation technique and then apply fuzzy programming to solve it. The applicability of our proposed method is shown by considering two numerical examples. At last, conclusions and future research directions regarding our study is included.     

Long-Time Oscillatory Energy Conservation of Total Energy-Preserving Methods for Highly Oscillatory Hamiltonian Systems

For an integrator when applied to a highly oscillatory system,the near conservation of the oscillatory energy over long times is an important aspect.In this paper,we study the long-time near conservation of oscillatory energy for the adapted average vector field(AAVF)method when applied to highly oscillatory Hamiltonian systems.This AAVF method is an extension of the average vector field method and preserves the total energy of highly oscillatory Hamiltonian systems exactly.This paper is devoted to analysing another important property of AAVF method,i.e.,the near conservation of its oscillatory energy in a long term.The long-time oscillatory energy conservation is obtained via constructing a modulated Fourier expansion of the AAVF method and deriving an almost invariant of the expansion.A similar result of the method in the multi-frequency case is also presented in this paper.     

On Global and Local Properties of the Trajectories of Gaussian Random Fields——A Look Through the Set of Limit Points

This paper studies the global and local properties of the trajectories of Gaussian random fields with stationary increments and proves sufficient conditions for Strassen's functional laws of the iterated logarithm at zero and infinity respectively.The sets of limit points of those Gaussian random fields are obtained.The main results are applied to fractional Riesz-Bessel processes and the sets of limit points of this field are obtained.     

FLUSHING TIME IN THE CIENFUEGOS BAY,CUBA

We use a high‐resolution numerical model to analyze the hydrodynamical exchange processes of the Cienfuegos Bay with the Caribbean Sea. Results show that freshwater inputs and wind are the main factors controlling the water exchange in the bay. Nine simulation case studies with three wind conditions and three freshwater inputs were carried out. The main conclusion is that the Cienfuegos Bay system has a slow exchange rate, with an average flushing time of 39 days during the rainy period and 50 days during the dry one, for the most probable wind direction. Two new temporary scales for Cienfuegos Bay are discussed: the local e‐flushing time and the flushing lag. The results obtained for these new variables validate the slow exchange capacity of the bay.     

技术创新扩散过程中市场酝酿期的模型分析

本文描述了技术创新扩散过程中的市场酝酿期 ,以 Bass模型为基础的分析结果表明 :市场酝酿期越长 ,新技术的创新系数就越小 ,扩散系数就越大 ,而且到达销售峰期的时间就越长 .本文同时对 2 8种耐用消费品的市场扩散进行了实证分析 ,得出了一些有用的结论     

随机环境下风险模型的破产问题

本文研究了在随机环境下风险模型的破产问题.利用递归方法,获得了破产前盈余的分布和描述破产严重性的预警区的分布, 推广了已有结果.     

流行病灭绝时间和费用估计随机模型

本文用具有吸收状态的生灭马氏过程建立了流行病随机模型,研究了灭绝之前生灭过程的分布,发现初始分布是拟平稳分布时,其灭绝时间服从指数分布,并得到了灭绝时间与状态概率的关系式和费用估计的期望值.应用模型给出了一个固定人口为N的流行病灭绝时间和平均费用的数值模拟结果.     

SOME EXTENSIONS OF THE MEAN CURVATURE FLOW IN RIEMANNIAN MANIFOLDS

Given a family of smooth immersions of closed hypersurfaces in a locally symmetric Riemannian manifold with bounded geometry,moving by mean curvature flow,we show that at the first finite singular time of mean curvature flow,certain subcritical quantities concerning the second fundamental form blow up.This result not only generalizes a result of Le-Sesum and Xu-Ye-Zhao,but also extends the latest work of Le in the Euclidean case.     

OPTIMAL MODELS FOR THE FIRST ARRIVAL TIME DISTRIBUTION FUNCTION IN CONTINUOUS TIME－WITH A SPECIAL CASE

ＯＰＴＩＭＡＬＭＯＤＥＬＳＦＯＲＴＨＥＦＩＲＳＴＡＲＲＩＶＡＬＴＩＭＥＤＩＳＴＲＩＢＵＴＩＯＮＦＵＮＣＴＩＯＮＩＮＣＯＮＴＩＮＵＯＵＳＴＩＭＥ－ＷＩＴＨＡＳＰＥＣＩＡＬＣＡＳＥＬＩＮＹＵＡＮＬＩＥ（林元烈）（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭａ...     

带息双二项风险模型的破产问题

本文研究了带随机利率的双二项风险模型的破产问题,得到了描述破产严重程度的破产前盈余分布,破产持续时间分布的递推公式,有限时间破产概率的递推公式及终极破产概率满足的积分方程.     

具有比率依赖和年龄结构的捕食食饵系统的分支研究

本文研究了具有比率依赖的捕食食饵的分支问题.利用线性特征方程的方法,获得了方程解的稳定性结果,得到了Hopf分支的方向和稳定性的充分条件.     

THE REDUCED BASIS TECHNIQUE AS A COARSE SOLVER FOR PARAREAL IN TIME SIMULATIONS

In this paper, we extend the reduced basis methods for parameter dependent problems to the parareal in time algorithm introduced by Lions et al. [12] and solve a nonlinear evolutionary parabolic partial differential equation. The fine solver is based on the finite element method or spectral element method in space and a semi-implicit Runge-Kutta scheme in time. The coarse solver is based on a semi-implicit scheme in time and the reduced basis approximation in space. Of[line-online procedures are developed, and it is proved that the computational complexity of the on-line stage depends only on the dimension of the reduced basis space （typically small）. Parareal in time algorithms based on a multi-grids finite element method and a multi-degrees finite element method are also presented. Some numerical results are reported.     

THE OCCUPATION DENSITY FIELD FOR THE CATALYTIC SUPER-BROWNIAN MOTION

61.IntroductionLetW=[w,,ll.,.,s,t2o,aER']denoteastandardBrownianmotioninRdwithsendgroup{Pt,t2o},C(R')denotetheBanachspaceofcontinuousboundedfunctionsonRdequlppedwiththesupnorm.rk.(a):=(1 Ial')-p/',aERd,Cr(R'):-{feC(R'),lf(x)l5CIof.(x)}withsomeconstantCj,Mv(R'):={pisffedonmeasureonRdandJ(1 lxlp)-'p(dx)d.(P,i):=ff(x)p(dx),AisLebesgUemeasure.GiventheordinaryMP-valuedsuper-Brownianmotiono:=[o,,fl1,Ps,#,t2s2O,pEMP]asthecatalyticmedium,Dawsona…