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151.
Yang et al. [J.P. Yang, S.H. Cheng, Q. Wu, Recursive equations for compound distribution with the severity distribution of the mixed type, Science in China Series A 48 (2005) 594-609] investigated a recursive procedure for a kind of compound distributions with the number of claims belonging to (a,b)-family and the severity distribution of the mixed type. In this paper, we extend their results by assuming that the claim number belongs to a larger class. As applications, the excess-of-loss reinsurance treaty is discussed and concrete examples are considered in some detail. 相似文献
152.
153.
154.
In this paper, two delayed SEIR epidemic models with continuous and impulsive vaccination and saturating incidence are investigated. The dynamical behaviors of the disease are analyzed. For continuous vaccination, we obtain a basic reproductive number R1 and prove that if R1≤1 then the disease-free equilibrium is globally attractive and if R1>1 then the disease is permanent by using the Lyapunov functional method. For impulsive vaccination, we obtain two thresholds R∗ and R∗ and prove that if R∗<1 then the disease-free periodic solution is globally attractive and if R∗>1 then the disease is permanent by using the comparison theorem of impulsive differential equation and the Lyapunov functional method. Lastly, we compared the effects of two vaccination strategies. 相似文献
155.
Chenping Hou Author Vitae Changshui Zhang Author Vitae Author Vitae Yuanyuan Jiao Author Vitae 《Pattern recognition》2009,42(9):2054-2066
Dimensionality reduction is a big challenge in many areas. A large number of local approaches, stemming from statistics or geometry, have been developed. However, in practice these local approaches are often in lack of robustness, since in contrast to maximum variance unfolding (MVU), which explicitly unfolds the manifold, they merely characterize local geometry structure. Moreover, the eigenproblems that they encounter, are hard to solve. We propose a unified framework that explicitly unfolds the manifold and reformulate local approaches as the semi-definite programs instead of the above-mentioned eigenproblems. Three well-known algorithms, locally linear embedding (LLE), laplacian eigenmaps (LE) and local tangent space alignment (LTSA) are reinterpreted and improved within this framework. Several experiments are presented to demonstrate the potential of our framework and the improvements of these local algorithms. 相似文献
156.
Xingwei Wang Lei Guo Xuekui Wang Yu Zhang Xiaobing Zheng Weigang Hou Hongming Li Hongpeng Wang 《Computer Communications》2009,32(4):777-781
This paper proposes a new survivable algorithm named sub-path protection based on auxiliary virtual topology (SPAVT) to tolerate the single-link failure in WDM optical networks. First, according to the protection-switching time constraint, SPAVT searches multiple pairs of primary and backup paths for each node pair in the network by the off-line manner, and then map these paths to the virtual topology. When a connection request arrives, SPAVT only needs to run one time of the Dijkstra’s algorithm to search a virtual route in virtual topology, where the route may consist of multiple pairs of sub-paths, to meet the protection-switching time constraint. Then, according to the shared resources policy, SPAVT chooses an optimal pair of sub-paths. Simulation results show that SPAVT has smaller blocking probability and lower time complexity than conventional algorithms. 相似文献
157.
This paper proposes a new approach, named Card-Aided Firewall (CAF) that combines the simplified firewall and the state-oriented smart card technologies to construct a controllable and accountable Internet access framework. The idea suggests that a client computer, protected by a light-weight firewall, could establish diversified authenticated communication channels, controlled and accounted by “legal” states of the smart card.The program of a smart card is state-oriented or a state machine, which defines a chain of events involving various state transitions. The “legal” states of a smart card program are defined to be legal to communicate with surfing targets. A predefined Access Control List (ACL), stored in the same card, is necessary. An ACL is a sequential list of permit or deny statements that apply to addresses or upper-layer protocols. The proposed firewall decides acceptance or rejection messages by matching the current state of the card program and the ACL. In addition, a complete surfing account for tracing back is recorded. It is a by-product of the smart card authentication.The proposed Card-Aided Firewall framework is implemented to demonstrate its effectiveness. The implementation is done at the driver level. It keeps up with the high line speed. The driver takes 39K bytes and works well with other firewalls. The average packet processing time of the CAF driver is 31.74 μs. On the premise of secure authentication within the smart card, the Card-Aided Firewall would facilitate various rapidly growing applications in campus cards, family cards, and employee cards, etc. that require accurate controllability and accountability in the surfing boundary. 相似文献
158.
We present a type of single-hidden layer feed-forward wavelet neural networks. First, we give a new and quantitative proof
of the fact that a single-hidden layer wavelet neural network with n + 1 hidden neurons can interpolate n + 1 distinct samples with zero error. Then, without training, we constructed a wavelet neural network X
a
(x, A), which can approximately interpolate, with arbitrary precision, any set of distinct data in one or several dimensions. The
given wavelet neural network can uniformly approximate any continuous function of one variable. 相似文献
159.
Short-term fault prediction based on support vector machines with parameter optimization by evolution strategy 总被引:3,自引:0,他引:3
Support vector machines (SVMs) are the effective machine-learning methods based on the structural risk minimization (SRM) principle, which is an approach to minimize the upper bound risk functional related to the generalization performance. The parameter selection is an important factor that impacts the performance of SVMs. Evolution Strategy with Covariance Matrix Adaptation (CMA-ES) is an evolutionary optimization strategy, which is used to optimize the parameters of SVMs in this paper. Compared with the traditional SVMs, the optimal SVMs using CMA-ES have more accuracy in predicting the Lorenz signal. The industry case illustrates that the proposed method is very successfully in forecasting the short-term fault of large machinery. 相似文献
160.
提出了一种新的用于灵活图像认证的多重水印嵌入算法.不同于传统的块独立水印算法中每个图像块只嵌入一个水印信息,算法对每个图像块嵌入多重水印信息.提出了两个通用的图像块等级模型,形成图像块内部的等级结构,对每个图像块以及图像块内部的各等级子块进行独立的水印生成和嵌入.将图像特征值映射为混沌系统的初值,并将图像块的编号映射为混沌系统的迭代次数,经过混沌迭代生成图像块水印,再将水印信号替代图像块中选定像素点的最低有效位,完成水印的嵌入.实验结果表明,该算法可对图像进行多重认证,对篡改区域进行精确的检测与定位,并能选择不同的定位精度. 相似文献