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141.
Small world network models have been effective in capturing the variable behaviour of reported case data of the SARS coronavirus outbreak in Hong Kong during 2003. Simulations of these models have previously been realized using informed “guesses” of the proposed model parameters and tested for consistency with the reported data by surrogate analysis. In this paper we attempt to provide statistically rigorous parameter distributions using Approximate Bayesian Computation sampling methods. We find that such sampling schemes are a useful framework for fitting parameters of stochastic small world network models where simulation of the system is straightforward but expressing a likelihood is cumbersome. 相似文献
142.
采用多面体表面模拟溶质空腔, 讨论了溶剂效应计算中近似积分方法和解析积分方法的平行性和收敛性. 我们发现: 对所研究的40个中性分子, 近似方法和解析方法之间的平行性较好; 但是, 对于20个正离子和27个负离子, 当溶质空腔分别为0.002和0.001 a.u.的等电荷密度面时, 近似方法和解析方法之间的平行性较差, 因此, 近似方法的可靠性不一定有保证. 我们还发现当多面体的表面无限趋近空腔的表面时, 不管采用何种多面体序列, 近似方法和解析方法的基态总能量都基本趋向同一极限值. 相似文献
143.
Bhaskar Bhattacharya 《Annals of the Institute of Statistical Mathematics》2002,54(3):565-576
Gamma distribution is one of the most used methods of modeling lifetime data. However, testing homogeneity of parameters of m 3 gamma distributions against order restrictions is almost non-existent in the current literature. We propose two methods to this end: one uses quadratic forms involving ratios of cumulants as test statistic and the other is a stepwise procedure which uses Fisher's method of combining p-values when shape parameters are equal but unknown. Both procedures allow use of arbitrary sample sizes of m populations. Test of the inequality restrictions as a null hypothesis against unrestricted alternatives is also considered. A Monte Carlo study of power at various alternatives shows that both methods are competitive when they are applicable. 相似文献
144.
本文利用对非牛顿粘性不可压缩流方程对时间 t的解析性和长时间渐近性估计 ,具体构造了它的近似惯性流形 ,并得出收敛阶估计 . 相似文献
145.
Large gaps in one-dimensional cutting stock problems 总被引:1,自引:0,他引:1
Its linear relaxation is often solved instead of the one-dimensional cutting stock problem (1CSP). This causes a difference between the optimal objective function values of the original problem and its relaxation, called a gap. The size of this gap is considered in this paper with the aim to formulate principles for the construction of instances of the 1CSP with large gaps. These principles are complemented by examples for such instances. 相似文献
146.
To facilitate the evaluation of tradeoffs and the articulation of preferences in multiple criteria decision-making, a multiobjective decomposition scheme is proposed that restructures the original problem as a collection of smaller-sized subproblems with only subsets of the original criteria. A priori preferences on objective tradeoffs are integrated into this process by modifying the ordinary Pareto order by more general domination cones, and decision makers are supported by an interactive decision-making procedure to coordinate any remaining tradeoffs using concepts of approximate efficiency. A theoretical foundation for this method is provided, and an illustrative application to multiobjective portfolio optimization is described in detail. 相似文献
147.
This paper deals with the approximate controllability for the semilinear retarded control system. We will also derive the equivalent relation between controllability and stabilizability of the solution for the corresponding linear control system. 相似文献
148.
Peter H. van der Kamp 《Foundations of Computational Mathematics》2009,9(5):559-597
We globally classify two-component evolution equations, with homogeneous diagonal linear part, admitting infinitely many approximate
symmetries. Important ingredients are the symbolic calculus of Gel’fand and Dikiĭ, the Skolem–Mahler–Lech theorem, an algorithm
of Smyth, and results on diophantine equations in roots of unity obtained by Beukers.
相似文献
149.
L. Lei 《Journal of Optimization Theory and Applications》2008,137(1):185-204
This work is concerned with the identification problem for the perturbation term or error term in a parabolic partial differential
equation through its approximate periodic solutions. The observation is made over a subregion of the physical domain. The
existence and uniqueness problem of the approximate periodic solutions is studied in the first part of the paper. A solution
to the identification problem is given in the second part of the paper. The main ingredients to be used include the classical
Galerkin method and the unique continuation property for a parabolic system.
This work was supported by the National Natural Science Foundation of China Grant 10571161. 相似文献
150.
Yong-Soo Jung 《Journal of Mathematical Analysis and Applications》2008,339(1):108-114
Let A be a unital normed algebra and let M be a unitary Banach left A-module. If f:A→M is an approximate module left derivation, then f:A→M is a module left derivation. Moreover, if M=A is a semiprime unital Banach algebra and f(tx) is continuous in t∈R for each fixed x in A, then every approximately linear left derivation f:A→A is a linear derivation which maps A into the intersection of its center Z(A) and its Jacobson radical rad(A). In particular, if A is semisimple, then f is identically zero. 相似文献