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991.
Xinghua Fan Shouxiang YangJiuli Yin Lixin Tian 《Applied mathematics and computation》2011,217(9):4812-4818
Travelling wave solutions for the general modified CH-DP equation ut − uxxt + αu2ux − βuxuxx = uuxxx are developed. By using the dynamical system method, a peakon and a dark soliton are found to coexist for the same wave speed. Exact explicit blow-up solutions are given. By using numerical simulation, a loop solution for a special case is discussed. 相似文献
992.
Analytic Hardy and BMO spaces on the quantum torus are introduced. Some basic properties of these spaces are presented. In particular, the associated H 1-BMO duality theorem is proved. Finally, we discuss some possible extensions of the obtained results. 相似文献
993.
994.
Tao Li Kaijin Hu Libo Cheng Yin Ding Yuxiang Ding Jinling Shao Liang Kong 《Applied Mathematical Modelling》2011
This study aimed to evaluate continuous and simultaneous variations of dental implant diameter and length, and to identify their relatively optimal ranges in the posterior mandible under biomechanical consideration. A 3D finite element model of a posterior mandibular segment with dental implant was created. Implant diameter ranged from 3.0 to 5.0 mm, and implant length ranged from 6.0 to 16.0 mm. The results showed that under axial load, the maximum Von Mises stresses in cortical and cancellous bones decreased by 76.53% and 72.93% respectively, with the increasing of implant diameter and length; and under buccolingual load, by 83.97% and 84.93%, respectively. Under both loads, the maximum displacements of implant-abutment complex decreased by 58.09% and 75.53%, respectively. The results indicate that in the posterior mandible, implant diameter plays more significant roles than length in reducing cortical bone stress and enhancing implant stability under both loads. Meanwhile, implant length is more effective than diameter in reducing cancellous bone stress under both loads. Moreover, biomechanically, implant diameter exceeding 4.0 mm and implant length exceeding 12.0 mm is a relatively optimal combination for a screwed implant in the posterior mandible with poor bone quality. 相似文献
995.
Outsourcing is a good strategy for firms that need to reduce operating costs and improve competitiveness and it is important that firms scientifically select appropriate outsourcing providers. Some efforts have been made to find systematic ways to deal with outsourcing problems, but these efforts incorrectly assumed that the criteria used in the decision process are independent, which is not true in the real world. In this study, we propose a new hybrid multiple criteria decision-making (MCDM) model, which addresses the dependent relationships between the various criteria. The relations-structure among the criteria is built with the aid of the decision-making trial and evaluation laboratory (DEMATEL) method. Decision-makers tend to hold diverse opinions about their preferences due to incomplete information and knowledge, or inherent conflict between various departments. We further used the fuzzy preference programming and the analytic network process (ANP) to form a model for the selection of partners for outsourcing providers. The proposed model can help practitioners improve their decision making process, especially when criteria are numerous and inter-related. The method is demonstrated using data from a Taiwanese airline. 相似文献
996.
Feng-Tao LiuYou-Hua Fan Jian-Hua Yin 《Journal of Computational and Applied Mathematics》2011,235(13):3889-3897
In many mountainous areas, landslides and slope instabilities frequently occur after heavy rainfall and earthquake, and result in enormous casualties and huge economic losses. In order to mitigate the landslides hazard efficiently, a method is required for a better understanding of stability analysis. Fortunately, upper bound theorem of limit analysis provides a practical and effective upper bound approach to evaluate the stability of slopes. And in this approach, the search for the minimum factor of safety can be formulated as a nonlinear constrained optimization. In general, the SQP-type algorithms are used to solve this optimization problem. However, it is quite time consuming and difficult to search the optimum from an arbitrary starting point based on the SQP-type algorithms. Fortunately, a QP-free algorithm based on penalty function and active-set strategy can be globally convergent toward the KKT points with arbitrary starting point, and the rate of convergence is local superlinear or even quadratic. Two classical problems of slope stability are solved by this QP-free algorithm. The results show that the QP-free algorithm would be the better choice than SQP-type algorithms for solving the nonlinear constrained optimization problem which is derived from the upper bound limit analysis of slope stability. 相似文献
997.
This letter studies identification problems of model orders using the Hankel matrix of impulse responses of a system and presents two order identification methods: one is based on the singularities or ratios of the Hankel matrix determinants and the other is based on the singular value decomposition of the Hankel matrix. A numerical example verifies the proposed methods. 相似文献
998.
A periodic mathematical model of cell populations affected by periodic radiation is presented and studied in this paper. We obtain some sufficient conditions on the permanence and extinction of the system. Furthermore, criteria on the existence and global asymptotic stability of unique positive periodic solutions are established. Some numerical examples are shown to verify our results. A discussion is presented for further study. 相似文献
999.
Optimal extension fields (OEF) are a class of finite fields used to achieve efficient field arithmetic, especially required
by elliptic curve cryptosystems (ECC). In software environment, OEFs are preferable to other methods in performance and memory
requirement. However, the irreducible binomials required by OEFs are quite rare. Sometimes irreducible trinomials are alternative
choices when irreducible binomials do not exist. Unfortunately, trinomials require more operations for field multiplication
and thereby affect the efficiency of OEF. To solve this problem, we propose a new type of irreducible polynomials that are
more abundant and still efficient for field multiplication. The proposed polynomial takes the advantage of polynomial residue
arithmetic to achieve high performance for field multiplication which costs O(m
3/2) operations in
\mathbbFp{\mathbb{F}_p} . Extensive simulation results demonstrate that the proposed polynomials roughly outperform irreducible binomials by 20%
in some finite fields of medium prime characteristic. So this work presents an interesting alternative for OEFs. 相似文献
1000.
证明了如何选取矩阵X,Y和Z使得下面的分块矩阵(AXYZ)取得它的极大秩和极小秩,这里A∈C~(m×n)是一个已知矩阵,X∈C~(m×k),Y∈C~(p×n)和Z∈C~(p×k)是三个任意矩阵. 相似文献