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991.
Bayes and empirical Bayes iteration estimators in two seemingly unrelated regression equations 总被引:3,自引:0,他引:3
WANG Lichun Institute of Applied Mathematics Chinese Academy of Sciences Beijing China 《中国科学A辑(英文版)》2005,48(9):1153-1168
For a system of two seemingly unrelated regression equations given by (?)(y_1 is an m×1 vector and y_2 is an n×1 vector,m≠n),employ- ing the covariance adjusted technique,we propose the parametric Bayes and empirical Bayes iteration estimator sequences for regression coefficients.We prove that both the covariance matrices converge monotonically and the Bayes iteration estimator squence is consistent as well.Based on the mean square error (MSE) criterion,we elaborate the su- periority of empirical Bayes iteration estimator over the Bayes estimator of single equation when the covariance matrix of errors is unknown.The results obtained in this paper further show the power of the covariance adiusted approach. 相似文献
992.
Let
be a compact Riemannian manifold without boundary. In this paper, we consider the first nonzero eigenvalue of the p-Laplacian
and we prove that the limit of
when
is 2/d(M), where d(M) is the diameter of M. Moreover, if
is an oriented compact hypersurface of the Euclidean space
or
, we prove an upper bound of
in terms of the largest principal curvature κ over M. As applications of these results, we obtain optimal lower bounds of d(M) in terms of the curvature. In particular, we prove that if M is a hypersurface of
then:
.
Mathematics Subject Classifications (2000): 53A07, 53C21. 相似文献
993.
Spiro?KarigiannisEmail author Maung?Min-Oo 《Annals of Global Analysis and Geometry》2005,28(4):371-394
This paper is a continuation of Math. Res. Lett. 12 (2005), 493–512. We first construct special Lagrangian submanifolds of the Ricci-flat Stenzel metric (of holonomy SU(n)) on the cotangent bundle of Sn by looking at the conormal bundle of appropriate submanifolds of Sn. We find that the condition for the conormal bundle to be special Lagrangian is the same as that discovered by Harvey–Lawson
for submanifolds in Rn in their pioneering paper, Acta Math. 148 (1982), 47–157. We also construct calibrated submanifolds in complete metrics with special holonomy G2 and Spin(7) discovered by Bryant and Salamon (Duke Math. J. 58 (1989), 829–850) on the total spaces of appropriate bundles over self-dual Einstein four manifolds. The submanifolds are
constructed as certain subbundles over immersed surfaces. We show that this construction requires the surface to be minimal
in the associative and Cayley cases, and to be (properly oriented) real isotropic in the coassociative case. We also make
some remarks about using these constructions as a possible local model for the intersection of compact calibrated submanifolds
in a compact manifold with special holonomy.
Mathematics Subject Classification (2000): 53-XX, 58-XX. 相似文献
994.
David?AldousEmail author Grégory?Miermont Jim?Pitman 《Probability Theory and Related Fields》2005,133(1):1-17
We study the asymptotics of the p-mapping model of random mappings on [n] as n gets large, under a large class of asymptotic regimes for the underlying distribution p. We encode these random mappings in random walks which are shown to converge to a functional of the exploration process of inhomogeneous random trees, this exploration process being derived (Aldous-Miermont-Pitman 2004) from a bridge with exchangeable increments. Our setting generalizes previous results by allowing a finite number of “attracting points” to emerge.Research supported by NSF Grant DMS-0203062.Research supported by NSF Grant DMS-0071468. 相似文献
995.
Tasuku?ToyonagaEmail author Takesh?Itoh Hiroaki?Ishii 《Fuzzy Optimization and Decision Making》2005,4(1):51-69
The main purpose of this paper is to present a crop planning problem for agricultural management under uncertainty. It is significant that agricultural managers assign their limited farmlands to cultivation of which crops in a season. This planning is called the crop planning problem and influences their incomes for the season. Usually, the crop planning problem is formulated as a linear programming problem. But there are many uncertain factors in agricultural problems, so future profits for crops are not certain values. A linear programming model with constant profit coefficients may not reflect the environment of decision making properly. Therefore, we propose a model of crop planning with fuzzy profit coefficients, and an effective solution procedure for the model. Furthermore, we extend this fuzzy model, setting the profit coefficients as discrete randomized fuzzy numbers. We show concrete optimal solutions for each models. 相似文献
996.
Let H
1,H
2, . . .,H
k+1 be a sequence of k+1 finite, undirected, simple graphs. The (multicolored) Ramsey number r(H
1,H
2,...,H
k+1) is the minimum integer r such that in every edge-coloring of the complete graph on r vertices by k+1 colors, there is a monochromatic copy of H
i
in color i for some 1ik+1. We describe a general technique that supplies tight lower bounds for several numbers r(H
1,H
2,...,H
k+1) when k2, and the last graph H
k+1 is the complete graph K
m
on m vertices. This technique enables us to determine the asymptotic behaviour of these numbers, up to a polylogarithmic factor, in various cases. In particular we show that r(K
3,K
3,K
m
) = (m
3 poly logm), thus solving (in a strong form) a conjecture of Erdos and Sós raised in 1979. Another special case of our result implies that r(C
4,C
4,K
m
) = (m
2 poly logm) and that r(C
4,C
4,C
4,K
m
) = (m
2/log2
m). The proofs combine combinatorial and probabilistic arguments with spectral techniques and certain estimates of character sums.* Research supported in part by a State of New Jersey grant, by a USA Israeli BSF grant and by a grant from the Israel Science Foundation. Research supported by NSF grant DMS 9704114. 相似文献
997.
Suppose that we are given a function f : (0, 1)→(0,1) and, for some unknown p∈(0, 1), a sequence of independent tosses of a p-coin (i.e., a coin with probability p of “heads”). For which functions f is it possible to simulate an f(p)-coin? This question was raised by S. Asmussen and J. Propp. A simple simulation scheme for the constant function f(p)≡1/2 was described by von Neumann (1951); this scheme can be easily implemented using a finite automaton. We prove that in
general, an f(p)-coin can be simulated by a finite automaton for all p ∈ (0, 1), if and only if f is a rational function over ℚ. We also show that if an f(p)-coin can be simulated by a pushdown automaton, then f is an algebraic function over ℚ; however, pushdown automata can simulate f(p)-coins for certain nonrational functions such as
. These results complement the work of Keane and O’Brien (1994), who determined the functions f for which an f(p)-coin can be simulated when there are no computational restrictions on the simulation scheme.
* Supported by a Miller Fellowship.
† Supported in part by NSF Grant DMS-0104073 and by a Miller Professorship.
‡ This work is supported under a National Science Foundation Graduate Research Fellowship. 相似文献
998.
Doo-Sung?LeeEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(4):487-494
Nonlinear asymmetric breakup of a circular capillary jet
stressed at the surface by an electrical field is presented. The
method of straining of coordinates is used to calculate the
cutoff wave number. The numerical results show that an initially
sinusoidal wave develops in an asymmetrical form by the
nonlinear effect from higher harmonics. It is shown that a
linear relation-ship exists between the breakup times and the
logarithms of the amplitudes of the wave. The slopes of these
lines can be used to calculate the actual growth rates. The
effective growth rates are displayed in a graphical form. 相似文献
999.
Peter Kop?anský Martina Koneracká Vlasta Závišová Katalin Fodor-Csorba Anikó Vajda Eric Beaugnon 《Journal of magnetism and magnetic materials》2010,322(22):3696-3700
The studied ferronematic is a nematic liquid crystal (ZLI1695) of low negative anisotropy of the diamagnetic susceptibility (χa<0) doped with the magnetic particles Fe3O4. Structural instabilities are interpreted within Burylov and Raikher's theory. The high magnetic fields were oriented perpendicular (Freedericksz transition) or parallel to the initial director. Using capacitance measurements the Freedericksz threshold magnetic field of the ferronematic BFN, and the critical magnetic field Bmax, at which the initial parallel orientation between the director and the magnetic moment of magnetic particles breaks down, have been determined. The values of these quantities have been used to estimate the surface density of the anchoring energy W of liquid crystal molecules on the surface of the magnetic particles. The obtained values indicate a soft anchoring of the liquid crystal on the magnetic particles with a preferred parallel orientation of the magnetic moment of magnetic particles and the director. 相似文献
1000.
Helena ?migoc 《Linear and Multilinear Algebra》2013,61(2):85-96
This article presents a technique for combining two matrices, an n?×?n matrix M and an m?×?m matrix B, with known spectra to create an (n?+?m???p)?×?(n?+?m???p) matrix N whose spectrum consists of the spectrum of the matrix M and m???p eigenvalues of the matrix B. Conditions are given when the matrix N obtained in this construction is nonnegative. Finally, these observations are used to obtain several results on how to construct a realizable list of n?+?1 complex numbers (λ1,λ2,λ3,σ) from a given realizable list of n complex numbers (c 1,c 2,σ), where c 1 is the Perron eigenvalue, c 2 is a real number and σ is a list of n???2 complex numbers. 相似文献