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51.
A polynomial Q = Q(X
1, …, X
n
) of degree m in independent identically distributed random variables with distribution function F is an unbiased estimator of a functional q(α
1(F), …, α
m
(F)), where q(u
1, …, u
m
) is a polynomial in u
1, …, u
m
and α
j
(F) is the jth moment of F (assuming the necessary moment of F exists). It is shown that the relation E(Q | X
1 + … + X
n) = 0 holds if and only if q(α
1(θ), …, α
m
(θ)) ≡ 0, where α
j
(θ) is the jth moment of the natural exponential family generated by F. This result, based on the fact that X
1 + … + X
n is a complete sufficient statistic for a parameter θ in a sample from a natural exponential family of distributions F
θ(x) = ∫−∞
x
e
θu−k(θ)
dF(u), explains why the distributions appearing as solutions of regression problems are the same as solutions of problems for
natural exponential families though, at the first glance, the latter seem unrelated to the former. 相似文献
52.
In this paper, we introduce a new definition of lower and upper solutions for boundary value problem of first order impulsive functional differential equations with nonlinear multi-point boundary conditions. By developing a new maximum principle and using the monotone iterative technique, we obtain the extremal solutions of the boundary value problem. 相似文献
53.
给定A∈Mn(F),g(x)=x3+ax2+bx+c∈F[x],本文讨论矩阵方程g(X)=A的解的存在性问题.在Li′s研究的基础上,当f(x)=p1(x)p2(x)…ps(x)时,我们给出g(X)=A有解的充要条件为对每一个pi(x),pi(g(x))在F[x]中存在ni次因式,ni=degpi(x). 相似文献
54.
Wireless Sensor Network has attracted a lot of attentions due to its broad applications in recent years and also introduces
many challenges. Network lifetime is a critical issue in Wireless Sensor Networks. It is possible to extend network lifetime
by organizing the sensors into a number of sensor covers. However, with the limited bandwidth, coverage breach (i.e, targets
that are not covered) can occur if the number of available time-slots/channels is less than the number of sensors in a sensor
cover. In this paper, we study a joint optimization problem in which the objective is to minimize the coverage breach as well
as to maximize the network lifetime. We show a “trade-off” scheme by presenting two strongly related models, which aim to
tradeoffs between the two conflicting objectives. The main approach of our models is organizing sensors into non-disjoint
sets, which is different from the current most popular approach and can gain longer network lifetime as well as less coverage
breach. We proposed two algorithms for the first model based on linear programming and greedy techniques, respectively. Then
we transform these algorithms to solve the second model by revealing the strong connection between the models. Through numerical
simulation, we showed the good performance of our algorithms and the pictures of the tradeoff scheme in variant scenarios,
which coincide with theoretical analysis very well. It is also showed that our algorithms could obtain less breach rate than
the one proposed in (Cheng et al. in INFOCOM’ 05, 2005). 相似文献
55.
Dan Mu Jiong Sun Dept. of Math. Inner Mongolia University Hohhot 《Annals of Differential Equations》2010,(1):45-52
The problem of J-selfadjointness of the product of two nth-order J-symmetric operators on [a,b] is studied. We give a condition to ensure that the product operator is a J-selfadjoint extension. 相似文献
56.
Nasser Metwally 《Physics letters. A》2011,375(48):4268-4273
A theoretical scheme is introduced to generate entangled network via Dzyaloshinskii-Moriya (DM) interaction. The dynamics of entanglement between different nodes, which is generated by direct or indirect interaction, is investigated. It is shown that, the direction of (DM) interaction and the locations of the nodes have a sensational effect on the degree of entanglement. The minimum entanglement generated between all the nodes is quantified. The upper and lower bounds of the entanglement depend on the direction of DM interaction, and the repetition of the behavior depends on the strength of DM. The generated entangled nodes are used as quantum channel to perform quantum teleportation, where it is shown that the fidelity of teleporting unknown information between the network members depends on the locations of the members. 相似文献
57.
We consider the detection problem of a two-dimensional function from noisy observations of its integrals over lines. We study
both rate and sharp asymptotics for the error probabilities in the minimax setup. By construction, the derived tests are non-adaptive.
We also construct a minimax rate-optimal adaptive test of rather simple structure. 相似文献
58.
59.
60.
Flow through a channel whose walls are lined with non-erodible porous material is investigated using Beavers and Joseph slip
boundary condition. It is shown that the effect of porous lining is to increase the mass flow rate and to decrease the friction
factor. 相似文献