Browsing by Author "Ma, Chunsheng"
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A class of stationary random fields with a simple correlation structure
Ma, Chunsheng (Academic Press, 20040715)A stationary random field is often more complicated than a univariate stationary time series, since dependence for a random field extends in all directions, while there is only the natural distinction of past and future ... 
Binomialchi(2) vector random fields
Ma, Chunsheng (SIAM Publ., 2017)We introduce a new class of nonGaussian vector random fields in space and/or time, which are termed binomialchi(2) vector random fields and include chi(2) vector random fields as special cases. We define a binomialchi(2) ... 
Covariance matrices for secondorder vector random fields in space and time
Ma, Chunsheng (IEEE, 20110501)This paper deals with vector (or multivariate) random fields in space and/or time with secondorder moments, for which a framework is needed for specifying not only the properties of each component but also the possible ... 
Covariance matrix functions of isotropic vector random fields
Wang, Renxiang; Du, Juan; Ma, Chunsheng (Taylor & Francis Group, 20140515)An isotropic scalar or vector random field is a secondorder random field in (d > 2), whose covariance function or direct/cross covariance functions are isotropic. While isotropic scalar random fields have been well developed ... 
Covariance structures of Gaussian and logGaussian vector stochastic processes
Metheny, Maryssa (Wichita State University, 201212)Although the covariance structures of univariate Gaussian and log Gaussian stochastic processes have been extensively studied in the past few decades, the development of covariance structures for Gaussian and logGaussian ... 
Hyperbolic vector random fields with hyperbolic direct and cross covariance functions
Du, Juan; Leonenko, Nikolai; Ma, Chunsheng; Shu, Hong (Taylor & Francis, 20120626)This article introduces the hyperbolic vector random field whose finitedimensional distributions are the generalized hyperbolic one, which is formulated as a scale mixture of Gaussian random fields and is thus an elliptically ... 
Isotropic covariance matrix functions on all spheres
Ma, Chunsheng (Springer International Publishing AG, 201508)This paper reviews and introduces characterizations of the covariance function on all spheres that is isotropic and continuous, and characterizations of the covariance matrix function on all spheres whose entries are ... 
Isotropic covariance matrix functions on compact twopoint homogeneous spaces
Lu, Tianshi; Ma, Chunsheng (Springer, 2019)The covariance matrix function is characterized in this paper for a Gaussian or elliptically contoured vector random field that is stationary, isotropic, and mean square continuous on the compact twopoint homogeneous ... 
Isotropic covariance matrix polynomials on spheres
Ma, Chunsheng (Taylor & Francis Group, 2016)This article characterizes the covariance matrix function of a Gaussian or elliptically contoured vector random field that is stationary, isotropic, and mean square continuous on the sphere. By applying the characterization ... 
Isotropic positive definite functions on spheres generated from those in Euclidean spaces
Nie, Zhihui (Wichita State University, 201905)In this thesis, author have reviewed the classical characterizations of isotropic positive definite functions on Euclidean spaces and spheres, and had applied them to develop a construction of isotropic positive de nite ... 
Isotropic random fields with infinitely divisible marginal distributions
Wang, Fangfang; Leonenko, Nikolai; Ma, Chunsheng (Taylor & Francis, 2018)A simple but efficient approach is proposed in this paper to construct the isotropic random field in (d 2), whose univariate marginal distributions may be taken as any infinitely divisible distribution with finite variance. ... 
Isotropic variogram matrix functions on spheres
Du, Juan; Ma, Chunsheng; Li, Yang (SPRINGER, 201304)This paper is concerned with vector random fields on spheres with secondorder increments, which are intrinsically stationary and mean square continuous and have isotropic variogram matrix functions. A characterization of ... 
Kdifferenced vector random fields
Alsultan, Rehab (Wichita State University, 201505)There is a great demand for analyzing multivariate measurements observed across space and over time, due to an increasing wealth of multivariate spatial, temporal, or spatiotemporal data, which may be treated as the ... 
Kdifferenced vector random fields
Alsultan, Rehab; Ma, Chunsheng (SIAM Publ., 2019)A thintailed vector random field, referred to as a Kdifferenced vector random field, is introduced. Its finitedimensional densities are the differences of two Besse! functions of second order, whenever they exist, and ... 
Kdistributed vector random fields in space and time
Ma, Chunsheng (Elsevier, 201304)This paper introduces two types of secondorder vector random fields or stochastic processes whose marginals are Kdistributed, through certain mixture procedures. The first type is formulated as an independent product of ... 
Logistic vector random fields with logistic direct and cross covariances
Balakrishnan, N.; Ma, Chunsheng; Wang, Renxiang (Elsevier B.V., 201506)The logistic vector random field is introduced in this paper as a scale mixture of Gaussian vector random fields, and is thus a particular elliptically contoured (spherically invariant) vector random field. Such a logistic ... 
Matchedpairs tests of homogeneity with applications to homologous nucleotide sequences
Ababneh, Faisal; Jermiin, Lars S.; Ma, Chunsheng; Robinson, John (Oxford University Press, 20060515)Motivation: Most phylogenetic methods assume that the sequences of nucleotides or amino acids have evolved under stationary, reversible and homogeneous conditions. When these assumptions are violated by the data, there ... 
MittagLeffler vector random fields with MittagLeffler direct and cross covariance functions
Ma, Chunsheng (Springer Heidelberg, 201310)In terms of the twoparameter MittagLeffler function with specified parameters, this paper introduces the MittagLeffler vector random field through its finitedimensional characteristic functions, which is essentially ... 
Multifractional vector Brownian motions, their decompositions, and generalizations
Ma, Chunsheng (Taylor & Francis Group, 20150504)This article introduces three types of covariance matrix structures for Gaussian or elliptically contoured vector random fields in space and/or time, which include fractional, bifractional, and trifractional vector Brownian ... 
Peakedness and convex ordering for elliptically contoured random fields
Wang, Fangfang; Ma, Chunsheng (Elsevier, 201812)For the peakedness comparison between two Gaussian random fields about their mean functions, a necessary and sufficient condition is derived in this paper in terms of their covariance functions. interestingly, such a ...