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基于Fisher线性判别率的加权K-means聚类算法 被引量:5
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作者 杨鹤标 薛艳锋 +2 位作者 冯进兰 沈项军 吴静丽 《计算机应用研究》 CSCD 北大核心 2010年第12期4439-4442,共4页
为提高K-means聚类效果,采用Fisher线性判别率的方法确定特征在聚类中的贡献度并依此对特征进行加权聚类。在人工和实际数据集上所做的实验表明,本方法在聚类效果上优于其他同类加权K-means聚类算法。
关键词 K- 聚类 Fisher线性判别率 特征加权 调整随机指标 类内错误率均方和
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一种改进的宏块层码率控制策略
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作者 尹明 刘传清 李旭涛 《火力与指挥控制》 CSCD 北大核心 2009年第9期154-157,共4页
利用DCT域中交流系数的均方和代替像素域的方差,作为宏块运动复杂度的表征,并将改进后的码率模型运用于H.264的码率控制策略。仿真结果表明,与现有的码率控制算法相比,改进方案可以在不同的目标码率下更有效地控制码率的波动,改善了PSN... 利用DCT域中交流系数的均方和代替像素域的方差,作为宏块运动复杂度的表征,并将改进后的码率模型运用于H.264的码率控制策略。仿真结果表明,与现有的码率控制算法相比,改进方案可以在不同的目标码率下更有效地控制码率的波动,改善了PSNR增益。在图像质量方面更平稳,有效地改善了主观视觉质量。 展开更多
关键词 H.264 码率控制 DCT域 均方和
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改进的宏块层码率控制策略
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作者 尹明 刘传清 《计算机应用》 CSCD 北大核心 2007年第12期3048-3050,3054,共4页
利用DCT域中交流系数的均方和代替像素域的方差,作为宏块运动复杂度的表征,并将改进后的码率模型运用于H.264的码率控制策略。仿真结果表明,与现有的码率控制算法相比,改进方案可以在不同的目标码率下更有效地控制码率的波动,改善了PSN... 利用DCT域中交流系数的均方和代替像素域的方差,作为宏块运动复杂度的表征,并将改进后的码率模型运用于H.264的码率控制策略。仿真结果表明,与现有的码率控制算法相比,改进方案可以在不同的目标码率下更有效地控制码率的波动,改善了PSNR增益。在图像质量方面更平稳,有效改善了主观视觉质量。 展开更多
关键词 H.264 码率控制 DCT域 均方和
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Convection in the Rayleigh-Bénard Flow with all Fluid Properties Variable 被引量:1
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作者 Athanasios Sassos Asterios Pantokratoras 《Journal of Thermal Science》 SCIE EI CAS CSCD 2011年第5期454-459,共6页
In the present paper, the effect of variable fluid properties (density, viscosity, thermal conductivity and specific heat) on the convection in the classical Rayleigh-Benard problem is investigated. The investigatio... In the present paper, the effect of variable fluid properties (density, viscosity, thermal conductivity and specific heat) on the convection in the classical Rayleigh-Benard problem is investigated. The investigation concerns water, air, and engine oil by taking into account the variation of fluid properties with temperature. The results are obtained by numerically solving the governing equations, using the SIMPLE algorithm and covering large temperature differences. It is found that the critical Rayleigh number increases as the temperature difference increases considering all fluid properties variable. However, when the fluid properties are kept constant, calculated at the mean temperature, and only density is considered variable, the critical Rayleigh number either decreases or remains constant. 展开更多
关键词 Rayleigh-Benard variable properties ONSET numerical investigation.
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On the Dedekind Sums and Two-Term Exponential Sums
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作者 Di HAN Tingting WANG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2015年第4期603-612,共10页
In this paper, the authors use the analytic methods and the properties of character sums mod p to study the computational problem of one kind of mean value involving the classical Dedekind sums and two-term exponentia... In this paper, the authors use the analytic methods and the properties of character sums mod p to study the computational problem of one kind of mean value involving the classical Dedekind sums and two-term exponential sums, and give an exact computational formuiu for it. 展开更多
关键词 Dedekind sums Two-term exponential sums Mean value Computational formula
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Computational analysis of deleterious missense mutations in aspartoacylase that cause Canavan's disease
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作者 SREEVISHNUPRIYA K. CHANDRASEKARAN P. +6 位作者 SENTHILKUMAR A. SETHUMADHAVAN R. SHANTHI V. DAISY P. NISHA J. RAMANATHAN K. RAJASEKARAN R. 《Science China(Life Sciences)》 SCIE CAS 2012年第12期1109-1119,共11页
In this work, the most detrimental missense mutations of aspartoacylase that cause Canavan's disease were identified computationally and the substrate binding efficiencies of those missense mutations were analyzed... In this work, the most detrimental missense mutations of aspartoacylase that cause Canavan's disease were identified computationally and the substrate binding efficiencies of those missense mutations were analyzed. Out of 30 missense mutations, I-Mutant 2.0, SIFT and PolyPhen programs identified 22 variants that were less stable, deleterious and damaging respectively. Subsequently, modeling of these 22 variants was performed to understand the change in their conformations with respect to the native aspartoacylase by computing their root mean squared deviation (RMSD). Furthermore, the native protein and the 22 mutants were docked with the substrate NAA (N-Acetyl-Aspartic acid) to explain the substrate binding efficiencies of those detrimental missense mutations. Among the 22 mutants, the docking studies identified that 15 mutants caused lower binding affinity for NAA than the native protein. Finally, normal mode analysis determined that the loss of binding affinity of these 15 mutants was caused by altered flexibility in the amino acids that bind to NAA compared with the native protein. Thus, the pre- sent study showed that the majority of the substrate-binding amino acids in those 15 mutants displayed loss of flexibility, which could be the theoretical explanation of decreased binding affinity between the mutant aspartoacylases and NAA. 展开更多
关键词 missense mutation Canavan's disease ASPARTOACYLASE NAA FLEXIBILITY
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The Hybrid Power Mean Involving the Character Sum of Polynomials and a Sum Analogous to Kloosterman Sum
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作者 LU Xingxing ZHANG Wenpeng 《数学进展》 2024年第6期1199-1209,共11页
The main purpose of this paper is using the properties of the classical Gauss sum and the analytic methods to study the computational problem of one kind of hybrid power mean involving the character sum of polynomials... The main purpose of this paper is using the properties of the classical Gauss sum and the analytic methods to study the computational problem of one kind of hybrid power mean involving the character sum of polynomials and a sum analogous to Kloosterman sum mod p,an odd prime,and give two sharp asymptotic formulae for them. 展开更多
关键词 character sum of polynomials a sum analogous to Kloosterman sum hybrid power mean the classical Gauss sum analytic method asymptotic formula
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