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101.
Rong ZhuSherry Z.F. Zhou 《Computational statistics & data analysis》2011,55(7):2312-2323
This paper considers the estimation of the error variance after a pre-test of an interval restriction on the coefficients. We derive the exact finite sample risks of the interval restricted and pre-test estimators of the error variance, and examine the risk properties of the estimators to model misspecification through the omission of relevant regressors. It is found that the pre-test estimator performs better than the interval restricted estimator in terms of the risk properties in a large region of the parameter space; moreover, its risk performance is more robust with respect to the degrees of model misspecification. Furthermore, we propose a bootstrap procedure for estimating the risks of the estimators, to overcome the difficulty of computing the exact risks. 相似文献
102.
A certifying algorithm for a problem is an algorithm that provides a certificate with each answer that it produces. The certificate is an evidence that can be used to authenticate the correctness of the answer. A Hamiltonian cycle in a graph is a simple cycle in which each vertex of the graph appears exactly once. The Hamiltonian cycle problem is to determine whether or not a graph contains a Hamiltonian cycle. The best result for the Hamiltonian cycle problem on circular-arc graphs is an O(n2logn)-time algorithm, where n is the number of vertices of the input graph. In fact, the O(n2logn)-time algorithm can be modified as a certifying algorithm although it was published before the term certifying algorithms appeared in the literature. However, whether there exists an algorithm whose time complexity is better than O(n2logn) for solving the Hamiltonian cycle problem on circular-arc graphs has been opened for two decades. In this paper, we present an O(Δn)-time certifying algorithm to solve this problem, where Δ represents the maximum degree of the input graph. The certificates provided by our algorithm can be authenticated in O(n) time. 相似文献
103.
104.
105.
Given a set of n intervals representing an interval graph, the problem of finding a maximum matching between pairs of disjoint (nonintersecting)
intervals has been considered in the sequential model. In this paper we present parallel algorithms for computing maximum
cardinality matchings among pairs of disjoint intervals in interval graphs in the EREW PRAM and hypercube models. For the
general case of the problem, our algorithms compute a maximum matching in O( log
3
n) time using O(n/ log
2
n) processors on the EREW PRAM and using n processors on the hypercubes. For the case of proper interval graphs, our algorithm runs in O( log n ) time using O(n) processors if the input intervals are not given already sorted and using O(n/ log n ) processors otherwise, on the EREW PRAM. On n -processor hypercubes, our algorithm for the proper interval case takes O( log n log log n ) time for unsorted input and O( log n ) time for sorted input. Our parallel results also lead to optimal sequential algorithms for computing maximum matchings
among disjoint intervals. In addition, we present an improved parallel algorithm for maximum matching between overlapping
intervals in proper interval graphs.
Received November 20, 1995; revised September 3, 1998. 相似文献
106.
Ting-Nung Shiau Chung-Hao Kang De-Shin Liu 《Structural and Multidisciplinary Optimization》2008,36(6):623-631
A new interval optimization algorithm is presented in this paper. In engineering, most optimization algorithms focus on exact
parameters and optimum objectives. However, exact parameters are not easy to be manufactured to because of manufacturing errors
and expensive manufacturing cost. To account for these problems, it is necessary to estimate interval design parameters and
allowable objective error. This is the first paper to propose a new interval optimization algorithm within the context of
Genetic Algorithms. This new algorithm, the Interval Genetic Algorithm (IGA), can neglect interval analysis and determines
the optimum interval parameters. Furthermore, it can also effectively maximize the design scope. The optimizing ability of
the IGA is tested through the interval optimization of a two-dimensional function. Then the IGA is applied to rotor-bearing
systems. The results show that the IGA is effective in deriving optimal interval design parameters within the allowable error
when minimizing shaft weight and/or transmitted force of rotor-bearing systems. 相似文献
107.
从2773份植物根际土的线虫标本中获得环科线虫标样648份,主要分布在中国的17个省区73个市县的67科189属246种寄主植物的根际土中。其中环科线虫在中国的寄主范围和地域分布均有很广泛,除西藏自治区和青海无报道外,其他各省区均有发现,发现环科数量较多的有8省31市县和地区,该线虫不但在玉米、大豆等各种作物根围发现,而且在各类花卉、树木、杂草等根际也广泛存在。 相似文献
108.
109.
通过对数据采集、数据利用、数据分析、数据跟踪等4个步骤的理论阐述、内容规划和关键技术研究,提出了以数据为核心进行农村水电综合管理信息系统建设的理论并结合广西地方水电信息管理系统的实际建设情况对其进行了实践验证,为农村水电站信息化建设探索了一条技术含量高、可持续发展、经济实用的新模式。 相似文献
110.
We propose a new technique combining dynamic and static analysis of programs to find linear invariants. We use a statistical tool, called simple component analysis, to analyze partial execution traces of a given program. We get a new coordinate system in the vector space of program variables, which is used to specialize numerical abstract domains. As an application, we instantiate our technique to interval analysis of simple imperative programs and show some experimental evaluations. 相似文献