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Sparse recovery in probability via $l_q$-minimization with Weibull random matrices for 0 < $q$ ≤ 1
GAO Yi, PENG Ji-gen, YUE Shi-gang
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 1-24.   DOI: 10.1007/s11766-018-3430-2
Abstract   ( 20 )  
Although Gaussian random matrices play an important role of measurement matrices in compressed sensing, one hopes that there exist other random matrices which can also be used to serve as the measurement matrices. Hence, Weibull random matrices induce extensive interest. In this paper, we first propose the $l_{2,q}$ robust null space property that can weaken the $D$-RIP, and show that Weibull random matrices satisfy the $l_{2,q}$ robust null space property with high probability. Besides, we prove that Weibull random matrices also possess the $l_q$ quotient property with high probability. Finally, with the combination of the above mentioned properties, we give two important approximation characteristics of the solutions to the $l_q$-minimization with Weibull random matrices, one is on the stability estimate when the measurement noise $e \in \mathbb{R}^n$ needs a priori $\|e\|_2\leq \epsilon$, the other is on the robustness estimate without needing to estimate the bound of $\|e\|_2$. The results indicate that the performance of Weibull random matrices is similar to that of Gaussian random matrices in sparse recovery.
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A perspective on recent methods on testing predictability of asset returns
LIAO Xiao-sai, CAI Zong-wu, CHEN Hai-qiang
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 127-.   DOI: 10.1007/s11766-018-3590-0
Abstract   ( 38 )  
This paper highlights some recent developments in testing predictability of asset returns with focuses on linear mean regressions, quantile regressions and nonlinear regression models. For these models, when predictors are highly persistent and their innovations are contemporarily correlated with dependent variable, the ordinary least squares estimator has a finite-sample bias, and its limiting distribution relies on some unknown nuisance parameter, which is not consistently estimable. Without correcting these issues, conventional test statistics are subject to a serious size distortion and generate a misleading conclusion in testing predictability of asset returns in real applications. In the past two decades, sequential studies have contributed to this subject and proposed various kinds of solutions, including, but not limit to, the bias-correction procedures, the linear projection approach, the IVX filtering idea, the variable addition approaches, the weighted empirical likelihood method, and the double-weight robust approach. Particularly, to catch up with the fast-growing literature in the recent decade, we offer a selective overview of these methods. Finally, some future research topics, such as the econometric theory for predictive regressions with structural changes, and nonparametric predictive models, and predictive models under a more general data setting, are also discussed.
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Waiting times and stopping probabilities for patterns in Markov chains
ZHAO Min-zhi, XU Dong, ZHANG Hui-zeng
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 25-34.   DOI: 10.1007/s11766-018-3522-z
Abstract   PDF (0KB) ( 28 )  
Suppose that $\mathcal C$ is a finite collection of patterns. Observe a Markov chain until one of the patterns in $\mathcal C$ occurs as a run. This time is denoted by $\tau$. In this paper, we aim to give an easy way to calculate the mean waiting time $E(\tau)$ and the stopping probabilities $P(\tau=\tau_A)$ with $A\in\mathcal C$, where $\tau_A$ is the waiting time until the pattern $A$ appears as a run.
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Nichols algebras over weak Hopf algebras
WU Zhi-xiang
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 107-126.   DOI: 10.1007/s11766-018-3327-0
Abstract   PDF (0KB) ( 24 )  
In this paper, we study a Yetter-Drinfeld module $V$ over a weak Hopf algebra $\mathbb{H}$. Although the category of all left $\mathbb{H}$-modules is not a braided tensor category, we can define a Yetter-Drinfeld module. Using this Yetter-Drinfeld modules $V$, we construct Nichols algebra $B(V)$ over the weak Hopf algebra $\mathbb{H}$, and a series of weak Hopf algebras. Some results of [8] are generalized.}
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2D-3D registration for 3D analysis of lower limb alignment in a weight-bearing condition
SHIM Eungjune, KIM Youngjun, LEE Deukhee, LEE Byung Hoon, WOO Sungkyung, LEE Kunwoo
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 59-70.   DOI: 10.1007/s11766-018-3459-2
Abstract   PDF (0KB) ( 34 )  
X-ray imaging is the conventional method for diagnosing the orthopedic condition of a patient. Computerized Tomography(CT) scanning is another diagnostic method that provides patient's 3D anatomical information. However, both methods have limitations when diagnosing the whole leg; X-ray imaging does not provide 3D information, and normal CT scanning cannot be performed with a standing posture. Obtaining 3D data regarding the whole leg in a standing posture is clinically important because it enables 3D analysis in the weight bearing condition. Based on these clinical needs, a hardware-based bi-plane X-ray imaging system has been developed; it uses two orthogonal X-ray images. However, such methods have not been made available in general clinics because of the hight cost. Therefore, we proposed a widely adaptive method for 2D X-ray image and 3D CT scan data. By this method, it is possible to three-dimensionally analyze the whole leg in standing posture. The optimal position that generates the most similar image is the captured X-ray image. The algorithm verifies the similarity using the performance of the proposed method by simulation-based experiments. Then, we analyzed the internal-external rotation angle of the femur using real patient data. Approximately 10.55 degrees of internal rotations were found relative to the defined anterior-posterior direction. In this paper, we present a useful registration method using the conventional X-ray image and 3D CT scan data to analyze the whole leg in the weight-bearing condition.
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Existence and uniqueness results for mild solutions of random impulsive abstract neutral partial differential equation over real axis
P Indhumathi, A Leelamani
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 71-87.   DOI: 10.1007/s11766-018-3449-4
Abstract   PDF (0KB) ( 30 )  
In this paper, we discuss the existence and uniqueness of mild solutions of random impulsive abstract neutral partial differential equations in a real separable Hilbert space. The results are obtained by using Leray-Schauder Alternative and Banach Contraction Principle. Finally an example is given to illustrate our problem.
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Large Variable selection via generalized SELO-penalized linear regression models
SHI Yue-yong , CAO Yong-xiu , YU Ji-chang , JIAO Yu-ling
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 145-.   DOI: 10.1007/s11766-018-3496-x
Abstract   ( 17 )  
The seamless-$L_0$ (SELO) penalty is a smooth function on $[0,\wq)$ that very closely resembles the $L_0$ penalty, which has been demonstrated theoretically and practically to be effective in nonconvex penalization for variable selection. In this paper, we first generalize SELO to a class of penalties retaining good features of SELO, and then propose variable selection and estimation in linear models using the proposed eneralized SELO (GSELO) penalized least squares (PLS) approach.
We show that the GSELO-PLS procedure possesses the oracle property and consistently selects the true model under some regularity conditions
in the presence of a diverging number of variables. The entire path of GSELO-PLS estimates can be efficiently computed through a smoothing quasi-Newton (SQN) method.
A modified BIC coupled with a continuation strategy is developed
to select the optimal tuning parameter.
Simulation studies and analysis of a clinical data
are carried out to evaluate the finite sample performance of the
proposed method. In addition, numerical experiments
involving simulation studies and analysis of a microarray data
are also conducted for GSELO-PLS in the high-dimensional settings.
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Data driven composite shape descriptor design for shape retrieval with a VoR-Tree
WANG Zi-hao, LIN Hong-wei, XU Chen-kai
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 88-106.   DOI: 10.1007/s11766-018-3536-6
Abstract   PDF (0KB) ( 20 )  
We develop a data driven method (probability model) to construct a composite shape descriptor by combining a pair of scale-based shape descriptors. The selection of a pair of scale-based shape descriptors is modeled as the computation of the union of two events, i.e., retrieving similar shapes by using a single scale-based shape descriptor. The pair of scale-based shape descriptors with the highest probability forms the composite shape descriptor. Given a shape database, the composite shape descriptors for the shapes constitute a planar point set. A VoR-Tree of the planar point set is then used as an indexing structure for efficient query operation. Experiments and comparisons show the effectiveness and efficiency of the proposed composite shape descriptor.
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On the strong convergence properties for weighted sums of negatively orthant dependent random variables
DENG Xin, TANG Xu-fei, WANG Shi-jie, WANG Xue-jun
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 35-47.   DOI: 10.1007/s11766-018-3423-1
Abstract   PDF (0KB) ( 24 )  
In the paper, the strong convergence properties for two different weighted sums of negatively orthant dependent (NOD) random variables are investigated. Let $\{X_n, n\geq1\}$ be a sequence of NOD random variables. The results obtained in the paper generalize the corresponding ones for i.i.d. random variables and identically distributed NA random variables to the case of NOD random variables, which are stochastically dominated by a random variable $X$. As a byproduct, the Marcinkiewicz-Zygmund type strong law of large numbers for NOD random variables is also obtained.
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Inference for a truncated positive normal distribution
Hector J. Gomez, Neveka M. Olmos, Hector Varela, Heleno Bolfarine
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 163-.   DOI: 10.1007/s11766-018-3354-x
Abstract   ( 17 )  
The main object of this paper is to study an extension of the half normal distribution defined by adding a positive truncation to it. The new model is more flexible than the half-normal distribution and contains the half normal distribution as a special case. Properties of this distribution, such as moments, hazard function and entropy are studied and parameters estimation is dealt with by using moments and maximum likelihood. A real data application indicates good fit performance of the new model when compared to other competitors in literatures.
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Modeling stochastic mortality with O-U type processes
ZHENG Jing, TONG Chang-qing, ZHANG Gui-jun
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (1): 48-58.   DOI: 10.1007/s11766-018-3349-7
Abstract   PDF (0KB) ( 19 )  
Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality over age group are linear, this is not the feature of mortality model. To avoid this disadvantage, O-U type processes will be used to model the log-mortality in this paper. In fact, this model is an AR(1) process, but with a nonlinear time drift term. Based on the mortality data of America from Human Mortality database (HMD), mortality projection consistently indicates a preference for mortality with O-U type processes over those with the classical Lee-Carter model. By means of this model, the low bounds of mortality rates at every age are given. Therefore, lengthening of maximum life expectancies span is estimated in this paper.
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A note on Pythagorean hodograph quartic spiral
ZHENG Zhi-hao , WANG Guo-zhao
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 234-252.   DOI: 10.1007/s11766-018-3465-4
Abstract   ( 16 )  
By using the geometric constraints on the control polygon of a Pythagorean hodograph (PH) quartic curve, we propose a sufficient condition for this curve to have monotone curvature and provide the detailed proof. Based on the results, we discuss the construction of spiral PH quartic curves between two given points and formulate the transition curve of a $G^2$ contact between two circles with one circle inside another circle. In particular, we deduce an attainable range of the distance between the centers of the two circles and summarize the algorithm for implementation. Compared with the construction of a PH quintic curve, the complexity of the solution of the equation for obtaining the transition curves is reduced.
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Characterizations of realized homogeneous Besov and Triebel-Lizorkin spaces via differences
MOUSSAI Madani
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 188-.   DOI: 10.1007/s11766-018-3431-1
Abstract   ( 11 )  
Based on the role of the polynomial functions on the homogeneous Besov spaces, on the homogeneous Triebel-Lizorkin spaces and on their realized versions, we study and obtain characterizations of these spaces via difference operators in a certain sense.
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Higher order asymptotic behaviour of partial maxima of random sample from generalized Maxwell distribution under power normalization
HUANG Jian-wen , WANG Jian-jun
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 177-.   DOI: 10.1007/s11766-018-3481-4
Abstract   ( 15 )  

In this article, the higher order asymptotic expansions of cumulative distribution function and probability density function of extremes for generalized Maxwell distribution are established under nonlinear normalization. As corollaries, the convergence rates of the distribution and density of maximum are obtained under nonlinear normalization.

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Double sampling derivatives and truncation error estimates
Rashad M. Asharabi , Aisha M. Al-Hayzea
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 209-.   DOI: 10.1007/s11766-018-3444-9
Abstract   ( 23 )  
This paper investigates double sampling series derivatives for bivariate functions defined on $\mathbb{R}^{2}$ that are in the Bernstein space.
For this sampling series, we estimate some of the pointwise and uniform bounds when the function satisfies some decay conditions. The truncated series of this formula allow us to approximate any order of partial derivatives for function from Bernstein space using only a finite number of samples from the function itself.
This sampling formula will be useful in the approximation theory and its applications, especially after having the truncation error well-established. Examples with tables and figures are given at the end of the paper to illustrate the advantages of this formula.
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The exponentiated generalized power Lindley distribution: Properties and applications
S.M.T.K. MirMostafaee Morad Alizadeh Emrah Altun Saralees Nadarajah
Applied Mathematics-A Journal of Chinese Universities    2019, 34 (2): 127-.   DOI: 10.1007/s11766-019-3515-6
Abstract   ( 17 )  
In this paper, we introduce a new extension of the power Lindley distribution, called
the exponentiated generalized power Lindley distribution. Several mathematical properties of
the new model such as the shapes of the density and hazard rate functions, the quantile function,
moments, mean deviations, Bonferroni and Lorenz curves and order statistics are derived.
Moreover, we discuss the parameter estimation of the new distribution using the maximum
likelihood and diagonally weighted least squares methods. A simulation study is performed to
evaluate the estimators. We use two real data sets to illustrate the applicability of the new
model. Empirical findings show that the proposed model provides better fits than some other
well-known extensions of Lindley distributions.
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Reconstruction of the Sturm-Liouville operator with discontinuities from a particular set of eigenvalues
XU Xiao-chuan , YANG Chuan-fu
Applied Mathematics-A Journal of Chinese Universities    2018, 33 (2): 225-.   DOI: 10.1007/s11766-018-3533-9
Abstract   ( 13 )  
Sturm-Liouville operators on a finite interval with discontinuities are considered. We give a uniqueness theorem for determining the potential and the parameters in boundary and under discontinuous conditions from a particular set of eigenvalues, and provide corresponding reconstruction algorithm, which can be applicable to McLaughlin-Rundell's uniqueness theorem (see J. Math. Phys. 28, 1987).
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HONG Hyokyoung Grace, LI Yi
Applied Mathematics-A Journal of Chinese Universities    2017, 32 (4): 379-.  
Abstract   PDF (0KB) ( 16 )  
Many modern biomedical studies have yielded survival data with high-throughput
predictors. The goals of scientific research often lie in identifying predictive biomarkers, understanding
biological mechanisms and making accurate and precise predictions. Variable screening
is a crucial first step in achieving these goals. This work conducts a selective review of feature
screening procedures for survival data with ultrahigh dimensional covariates. We present the
main methodologies, along with the key conditions that ensure sure screening properties. The
practical utility of these methods is examined via extensive simulations. We conclude the review
with some future opportunities in this field.
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Existence and Stability of Solutions to Highly Nonlinear Stochastic Differential Delay Equations Driven by G-Brownian Motion
FEI Chen, FEI Wei-yin, YAN Li-tan
Applied Mathematics-A Journal of Chinese Universities    2019, 34 (2): 184-.   DOI: 10.1007/s11766-019-3619-x
Abstract   ( 17 )  
Under linear expectation (or classical probability), the stability for stochastic differential
delay equations (SDDEs), where their coefficients are either linear or nonlinear but
bounded by linear functions, has been investigated intensively. Recently, the stability of highly
nonlinear hybrid stochastic differential equations is studied by some researchers. In this paper,
by using Peng’s G-expectation theory, we first prove the existence and uniqueness of solutions
to SDDEs driven by G-Brownian motion (G-SDDEs) under local Lipschitz and linear growth
conditions. Then the second kind of stability and the dependence of the solutions to G-SDDEs
are studied. Finally, we explore the stability and boundedness of highly nonlinear G-SDDEs.
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The closed finite-to-one mappings and their applications
YANG Jie, LIN Shou
Applied Mathematics-A Journal of Chinese Universities    2019, 34 (2): 149-.   DOI: 10.1007/s11766-019-3557-7
Abstract   ( 16 )  
In this paper, we discuss the closed finite-to-one mapping theorems on generalized
metric spaces and their applications. It is proved that point-G properties, @0-snf-countability
and csf-countability are invariants and inverse invariants under closed finite-to-one mappings.
By the relationships between the weak first-countabilities, we obtain the closed finite-to-one
mapping theorems of weak quasi-first-countability, quasi-first-countability, snf-countability, gf-
countability and sof-countability. Furthermore, these results are applied to the study of symmetric
products of topological spaces.
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