This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive ...This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive noise as α-stable distribution, new methods which combine the sparse signal representation technique and fractional lower order statistics theory are proposed. In the new algorithms, the fractional lower order statistics vectors of the array output signal are sparsely represented on an overcomplete basis and the DOAs can be effectively estimated by searching the sparsest coefficients. To enhance the robustness performance of the proposed algorithms,the improved algorithms are advanced by eliminating the fractional lower order statistics of the noise from the fractional lower order statistics vector of the array output through a linear transformation. Simulation results have shown the effectiveness of the proposed methods for a wide range of highly impulsive environments.展开更多
In this paper, we＇ll prove new representation theorems for a kind of second order stochastic integral- differential operator by stochastic differential equations （SDEs） and backward stochastic differential equatio...In this paper, we＇ll prove new representation theorems for a kind of second order stochastic integral- differential operator by stochastic differential equations （SDEs） and backward stochastic differential equations （BSDEs） with jumps, and give some applications.展开更多
We introduce the notion of symmetric covariation,which is a new measure of dependence between two components of a symmetricα-stable random vector,where the stability parameterαmeasures the heavy-tailedness of its di...We introduce the notion of symmetric covariation,which is a new measure of dependence between two components of a symmetricα-stable random vector,where the stability parameterαmeasures the heavy-tailedness of its distribution.Unlike covariation that exists only whenα∈(1,2],symmetric covariation is well defined for allα∈(0,2].We show that symmetric covariation can be defined using the proposed generalized fractional derivative,which has broader usages than those involved in this work.Several properties of symmetric covariation have been derived.These are either similar to or more general than those of the covariance functions in the Gaussian case.The main contribution of this framework is the representation of the characteristic function of bivariate symmetricα-stable distribution via convergent series based on a sequence of symmetric covariations.This series representation extends the one of bivariate Gaussian.展开更多
We unify and generalize several approaches to constructing braid group representa-tions from finite groups,using iterated twisted tensor products.We provide some general characterizations and classification of these r...We unify and generalize several approaches to constructing braid group representa-tions from finite groups,using iterated twisted tensor products.We provide some general characterizations and classification of these representations,focusing on the size of their images,which are typically finite groups.The well-studied Gaussian representations associated with metaplectic modular categories can be understood in this framework,and we give some new examples to illustrate their ubiquity.Our results suggest a relationship between the braiding on the G-gaugings of a pointed modular category C(A,Q)and that of C(A,Q)itself.展开更多
By using Frobenius maps and F-stable representations,we count the number of isomor- phism classes of indecomposable representations with the fixed dimension vector of a species of type _n over a finite field,first,and...By using Frobenius maps and F-stable representations,we count the number of isomor- phism classes of indecomposable representations with the fixed dimension vector of a species of type _n over a finite field,first,and then,as an application,give a q-analogue of the Weyl-Kac denominator identity of type _n.展开更多
基金supported in part by the National Natural Science Foundation of China(61301228,61371091)the Fundamental Research Funds for the Central Universities(3132014212)
文摘This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive noise as α-stable distribution, new methods which combine the sparse signal representation technique and fractional lower order statistics theory are proposed. In the new algorithms, the fractional lower order statistics vectors of the array output signal are sparsely represented on an overcomplete basis and the DOAs can be effectively estimated by searching the sparsest coefficients. To enhance the robustness performance of the proposed algorithms,the improved algorithms are advanced by eliminating the fractional lower order statistics of the noise from the fractional lower order statistics vector of the array output through a linear transformation. Simulation results have shown the effectiveness of the proposed methods for a wide range of highly impulsive environments.
基金Supported by the National Natural Science Foundation of China(No.11171186)the"111"project(No.B12023)
文摘In this paper, we＇ll prove new representation theorems for a kind of second order stochastic integral- differential operator by stochastic differential equations （SDEs） and backward stochastic differential equations （BSDEs） with jumps, and give some applications.
文摘We introduce the notion of symmetric covariation,which is a new measure of dependence between two components of a symmetricα-stable random vector,where the stability parameterαmeasures the heavy-tailedness of its distribution.Unlike covariation that exists only whenα∈(1,2],symmetric covariation is well defined for allα∈(0,2].We show that symmetric covariation can be defined using the proposed generalized fractional derivative,which has broader usages than those involved in this work.Several properties of symmetric covariation have been derived.These are either similar to or more general than those of the covariance functions in the Gaussian case.The main contribution of this framework is the representation of the characteristic function of bivariate symmetricα-stable distribution via convergent series based on a sequence of symmetric covariations.This series representation extends the one of bivariate Gaussian.
文摘We unify and generalize several approaches to constructing braid group representa-tions from finite groups,using iterated twisted tensor products.We provide some general characterizations and classification of these representations,focusing on the size of their images,which are typically finite groups.The well-studied Gaussian representations associated with metaplectic modular categories can be understood in this framework,and we give some new examples to illustrate their ubiquity.Our results suggest a relationship between the braiding on the G-gaugings of a pointed modular category C(A,Q)and that of C(A,Q)itself.
基金the Doctoral Program of Higher Education(Grant No.20030027002)
文摘By using Frobenius maps and F-stable representations,we count the number of isomor- phism classes of indecomposable representations with the fixed dimension vector of a species of type _n over a finite field,first,and then,as an application,give a q-analogue of the Weyl-Kac denominator identity of type _n.
文摘产品开发过程分工的加强、市场和全球化竞争的激烈都要求工厂能够更迅速地生产更廉价和质量更高的产品 ,而这需要一个更有效并且强有力的产品知识管理系统 ,以支持产品知识的表达、重用、共享和交流等 研究了产品知识表达的模型 ,即S B F ,结合本体描述语言构建了流本体和功能本体 ,设计出基于本体的产品知识表达 。
