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On asymptotics of t-type regression estimation in multiple linear model

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science china Mathematics 2004年第4期47卷 628-639页

作者： GUI Hengjiandepartment of Mathematics, beijing normal university, beijing 100875, china department of Mathematics Beijing Normal University Beijing China

We consider a robust estimator (t-type regression estimator) of multiple linear regression model by maximizing marginal likelihood of a scaled t-type error *** marginal likelihood can also be applied to the de-correlated response when the withinsubject correlation can be consistently estimated from an initial estimate of the model based on the independent working assumption. This paper shows that such a t-type estimator is consistent.

关键词： t-type regression estimator, M-estimator, one-step estimate, consistency, asymptotic normality.

A secure multi-party computation solution to intersection problems of sets and rectangles

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Progress in Natural science:materials International 2006年第5期16卷 538-545页

作者： LI Shundong, DAI Yiqi, WANG Daoshun and LUO Ping (department of Computer science and Technology, beijing normal university, beijing 100875, china department of Computer science and Technology, Tsinghua university, beijing 100084, china) department of Computer science and Technology Beijing Normal University Beijing 100875 China department of Computer science and Technology Tsinghua University Beijing 100084 China

Secure multi-party computation (SMC) is a research focus in international cryptographic community. At present, there is no SMC solution to the intersection problem of sets. In this paper, we first propose a SMC solution to this problem. Applying Cantor encoding method to computational geometry problems, and based on the solution to set-intersection problem, we further propose solutions to points inclusion problem and intersection problem of rectangles and further prove their privacy-preserving property with widely accepted simulation paradigm. Compared with the known solutions, these new solutions are of less computational complexity and less communication complexity, and have obvious superiority in computational and communication complexity.

关键词： Cantor encoding secure multi-party computation set-intersection rectangle-intersection computational complexity.

Linear estimation and distribution of the limit cycles bifurcated from a kind of degenerate polycycles

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science china Mathematics 2007年第3期50卷 334-344页

作者： Li-qin ZHAO department of Mathematics, beijing normal university, beijing 100875, china department of Mathematics Beijing Normal University Beijing China

In this paper, we investigate the number and the distribution of the limit cycles bifurcated from a kind of degenerate planar polycycles through three singular points: a saddle-node P 0, a fine saddle P 1 with finite order m ∈ N, a contractive (attracting) saddle P 2 with the hyperbolicity ratio q 2(0) ? Q. The connection between P 0 and P 1 is of hh-type and the connection between P 0 and P 2 is of hp-type. It is assumed that the connections between P 0 to P 2 and P 0 to P 1 keep unbroken. We obtain that the cyclicity of this polycycle is not more than 3m + 1, which is linearly dependent on the order of the resonant saddle P 1. We also show that the cyclicity is not more than m + 3 if q 2(0) > m, and that the nearer q 2(0) is close to 1, the more the limit cycles are bifurcated.

关键词： degenerate polycycle cyclicity finitely-smooth normal form transition map 34C05 34C23 58F14

Effects of surface modification on thermal cycling lifetime of thermal barrier coatings with HVOF NiCrAlY bond coat

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Progress in Natural science:materials International 2012年第3期22卷 237-243页

作者： Liyong Ni, Chungen Zhou department of materials science and engineering, beijing university of Aeronautics and Astronautics, beijing 100191, china department of materials science and engineering Beijing University of Aeronautics and Astronautics Beijing 100191 China

NiCrAlY bond coat was prepared by HVOF (high-velocity oxygen fuel) spray on nickel-based superalloy. Surface treatments like grit-blasting, shot-peening and vacuum treatment methods were carried out in order to study the effects of surface modification on thermal cycling lifetime of TBCs. The surface-modified TBCs exhibited better thermal shock resistance. Failure of TBCs with the as-sprayed bond coat occurred within the top coat and at the interface between spinels and the top coat, while that of after shot-peening, grit-blasting and vacuum treatment occurred mainly within the top coat. TGO (thermally grown oxide) formed on as-sprayed bond coat was composed of a Ni(Al,Cr)2O4 spinels outer layer and a Al2O3 inner layer. But, a continuous and uniform Al2O3 formed after surface modification. Formation of the mixed oxides (spinels) on the as-sprayed bond coat accelerated the failure of TBCs.

关键词： Thermal barrier coatings NiCrAlY HVOF Thermally grown oxide (TGO)

The Goldbach 3-primes property for polynomial rings over certain infinite fields

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Chinese science Bulletin 1998年第15期43卷 1256-1260页

作者： WANG Shiqiang department of Mathematics, beijing normal university, beijing 100875, china department of Mathematics Beijing Normal University Beijing China

On the basis of Effinger and Hayes’ theorem about the Goldbach 3_primes property of polynomial rings F over finite fields F , by model_theoretic method it is proved that for each characteristic k (including 0), there... 详细信息

关键词： model theory polynomial 3 primes property.

Quasi-critical ring of a primitive ring with nonzero socle

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Chinese science Bulletin 1997年第3期42卷 189-192页

作者： JIANG Zimeidepartment of Mathematics, beijing normal university, beijing 100875, china department of Mathematics Beijing Normal University Beijing China

IN ref. [1] Jacobson proved the structure theorem for primitive rings with nonzero socles that R is a primitive ring withsocle S≠{0} if and only if there is a pair of dual vector spaces (M,M’) over a division ring Δ such that S=F(M, M’)(?) R(?)(?)(M, M’), where (?)(M, M’)-{ω∈Ω|ωM’(?)M’, Ω is the complete ring of linear transformations of M over Δ}, F(M, M’) is the set of all linear transformations of (?)(M, M’) of finite rank. After that, some people reproved this theorem by using different methods such as those in refs. [2, 3]. In

关键词： primitive ring socle conjugate space total subspace of conjugate space.

Entropy number and non-linear approximations on multivariate Besov space by manifolds of finite pseudo-dimension

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Progress in Natural science:materials International 2006年第3期16卷 260-265页

作者： LONG Jingfan and FANG Gensun (School of Mathematical sciences, beijing normal university, beijing 100875, china department of Computer science, Information Technology Institute, beijing 100101, china) School of Mathematical sciences Beijing Normal University Beijing 100875 China department of Computer science Information Technology Institute Beijing 100101 China

We determine the asymptotic order of entropy number and optimal non -linear approximations of anisotropic periodic Besov class of Bpθr(Td') (1≤p≤∞,1≤0≤∞) by manifolds of finite pseudo-dimension in the metric Lq... 详细信息

关键词： Pseudo-dimension anisotropic Besov class of functions entropy number nonlinear width.

Crystallization Kinetics of NiTi Films with Different Ni Contents

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Journal of materials science & Technology 2001年第4期17卷 421-424页

作者： Xunyong JIANG, Huibin XU and Shengkai GONG department of materials science and engineering, beijing university of Aeronautics and Astronautics, beijing 100083, china Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

Three kinds of NiTi films with different Ni contents were prepared by DC magnetron sputtering. The crystallization kinetics of amorphous films was determined by using non-isothermal single- scan techniques. The results show that the activation energy of crystallization of Ni-rich NiTi film(Ni 51.10 at. pct, Ti 48.90 at. pct) is 715 kJ/mol; while that of Ti-rich films are similar: one is 445 kJ/mol (Ni 46.74 at. pct. Ti 53.26 at. pct), the other is 418 kJ/mol (Ni 43.21 at. pct, Ti 56.7g at. pct), which i5 lower than Ni-rich film. The Avrami parameter n of different films are 0.92 and 0.74 for Ni-rich film and Ti-rich films, respectively. The difference of kinetic parameters for NiTi films with various Ni contents implies that the crystallization behaviors of these films are distinct, which is confirmed by the calculated isothermal kinetics at different temperatures. The thorough research on this phenomenon is in progress.

关键词： NiTi Crystallization Kinetics of NiTi Films with Different Ni Contents

Sufficient and Necessary Conditions for Stochastic Comparability of Jump Processes

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Acta Mathematica Sinica,English Series 2000年第1期16卷 99-102页

作者： Yuhui Zhang department of Mathematics,beijing normal university,beijing 100875,P.R.china department of Mathematics Beijing Normal University Beijing 100875 P.R. China

This note is devoted to the study of the stochastic comparability of jump *** the basis of[2]and[3],it is proved that two jump processes are stochastically comparable if and only if their q-pairs are ***,the result co... 详细信息

关键词： Stochastically comparable Totally stable Conservative Uniqueness