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曲面片的可展度及其最佳展开基点 被引量:10
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作者 毛昕 《工程图学学报》 CSCD 1998年第2期1-11,共11页
本文通过对不可展曲面近似展开误差机理的分析研究,提出了曲面片最佳展开基点和曲面片可展度的概念和实现方法,研制了曲面展开和误差分析计算机辅助系统。实验证明,展开基点的选取和可展度的判别是提高曲面片展开精度的重要因素。
关键词 曲面 最佳开基点 可展度 开图
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曲面片的可展性能及其应用 被引量:4
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作者 毛昕 马明旭 王哲英 《工程图学学报》 CSCD 2002年第2期133-138,共6页
通过对曲面片可展性能及其应用的研究,在文献[1]的基础上更准确地给出了用可展度定量度量曲面片可展性能的概念和方法,同时给出了可展度在不可展曲面近似展开中的应用。一方面可以在曲面展开之前估计近似展开的误差,从而合理选择展开范... 通过对曲面片可展性能及其应用的研究,在文献[1]的基础上更准确地给出了用可展度定量度量曲面片可展性能的概念和方法,同时给出了可展度在不可展曲面近似展开中的应用。一方面可以在曲面展开之前估计近似展开的误差,从而合理选择展开范围;另一方面,基于最佳展开基点均匀分割曲面片可展度的假设,实现了近似展开中最佳展开基点的选取。 展开更多
关键词 曲面性 可展曲面 可展性能 可展度 开基点
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Adaptive clustering hierarchy routing for delay tolerant network 被引量:2
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作者 陶勇 王晓方 《Journal of Central South University》 SCIE EI CAS 2012年第6期1577-1582,共6页
Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combin... Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combination of single copy scheme and multi-copy scheme and the combination of hop-by-hop and multi-hop mechanism ACHR,which has the advantages in simplicity,availability and well-expansibility.The result shows that it can take advantage of the random communication opportunities and local network connectivity,and achieves 1.6 times delivery ratio and 60% overhead compared with its counterpart. 展开更多
关键词 delay tolerant network routing scheme congestion control hierarchy routing
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Dynamic assets allocation based on market microstructure model with variable-intensity jumps
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作者 覃业梅 彭辉 《Journal of Central South University》 SCIE EI CAS 2014年第3期993-1002,共10页
In order to characterizc large fluctuations of the financial markets and optimize financial portfolio, a new dynamic asset control strategy was proposed in this work. Firstly, a random process item with variable jump ... In order to characterizc large fluctuations of the financial markets and optimize financial portfolio, a new dynamic asset control strategy was proposed in this work. Firstly, a random process item with variable jump intensity was introduced to the existing discrete microstructure model to denote large price fluctuations. The nonparametric method of LEE was used for detecting jumps. Further, the extended Kalman filter and the maximum likelihood method were applied to discrete microstructure modeling and the estimation of two market potential variables: market excess demand and liquidity. At last, based on the estimated variables, an assets allocation strategy using evolutionary algorithm was designed to control the weight of each asset dynamically. Case studies on IBM Stock show that jumps with variable intensity are detected successfully, and the assets allocation strategy may effectively keep the total assets growth or prevent assets loss at the stochastic financial market. 展开更多
关键词 discrete microstrucmre model (DMSM) variable jump intensity evolutionary algorithm (EA) asset allocation excess demand market liquidity
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