This paper presents a trust region algorithm for nonlinear optimization with linear inequality constraints. The global convergence of the algorithm is proved. Local quadratic convergence is obtained for a strong local...This paper presents a trust region algorithm for nonlinear optimization with linear inequality constraints. The global convergence of the algorithm is proved. Local quadratic convergence is obtained for a strong local minimizer.展开更多
Acrylic acid was grafted onto the surface of cotton fabric after being short time treated by corona-discharge inair in the presence of initiator.The means of gas-phaseSO<sub>2</sub> derivatization was used...Acrylic acid was grafted onto the surface of cotton fabric after being short time treated by corona-discharge inair in the presence of initiator.The means of gas-phaseSO<sub>2</sub> derivatization was used along with ESCA to deter-mine corona-discharge-induced-hydroperoxidegroups on the surface.The content of hydroperoxideshows a maxmium value at 15 sec.of corona-dischargetime.Effect of corona treatment time and various con-centration initlator on graft yield was studied.The addit-ion of initiator increases the graft yield.Acceleratedgraft with an increase in the concentration of Mohr’s saltshows that peroxide groups on the corona treated cottonfabric initiate graft copolymerization.展开更多
Multiuser detection can be described as a quadratic optimization problem with binary constraint. Many techniques are available to find approximate solution to this problem. These tech- niques can be characterized in t...Multiuser detection can be described as a quadratic optimization problem with binary constraint. Many techniques are available to find approximate solution to this problem. These tech- niques can be characterized in terms of complexity and detection performance. The ＂efficient frontier＂ of known techniques include the decision-feedback, branch-and-bound and probabilistic data association detectors. The presented iterative multiuser detection technique is based on joint deregularized and box-constrained so- lution to quadratic optimization with iterations similar to that used in the nonstationary Tikhonov iterated algorithm. The deregulari- zation maximizes the energy of the solution, this is opposite to the Tikhonov regularization where the energy is minimized. However, combined with box-constraints, the deregularization forces the solution to be close to the binary set. We further exploit the box- constrained dichotomous coordinate descent （DCD） algorithm and adapt it to the nonstationary iterative Tikhonov regularization to present an efficient detector. As a result, the worst-case and aver- age complexity are reduced down to K28 and K2~ floating point operation per second, respectively. The development improves the ＂efficient frontier＂ in multiuser detection, which is illustrated by simulation results. Finally, a field programmable gate array （FPGA） design of the detector is presented. The detection performance obtained from the fixed-point FPGA implementation shows a good match to the floating-point implementation.展开更多
融合丰富度、均匀度与差异度的多维测度指标已成为衡量跨学科性的重要工具,然而,针对差异度对应的学科相似性度量方法对跨学科测度的具体影响尚缺乏系统讨论。为此,文章将学科分类层级、归一化系数、引用模式和时间窗口视为学科相似性...融合丰富度、均匀度与差异度的多维测度指标已成为衡量跨学科性的重要工具,然而,针对差异度对应的学科相似性度量方法对跨学科测度的具体影响尚缺乏系统讨论。为此,文章将学科分类层级、归一化系数、引用模式和时间窗口视为学科相似性度量的四个关键要素,通过构建相应的学科相似性矩阵,系统剖析各要素对跨学科测度结果的作用;在不同要素设定下,基于1981—2020年Web of Science收录的研究论文及其参考文献和施引文献数据构建学科相似性矩阵,并选取八本代表性期刊的论文展开实证分析。结果表明:不同层级的学科分类方式对学科相似性度量具有显著影响,进而导致跨学科测度结果存在系统性差异;在4种归一化系数下,运用Ochiai余弦所测得的学科相似性更低、跨学科性区分度更高;在不同引用模式和时间窗口设定下,各学科相似性度量结果对跨学科测度的影响并不显著。展开更多
基于Microfacet理论,当光线照射到粗糙表面时会发生显著的多次镜面反射现象,而传统偏振双向反射分布函数(Polarized Bidirectional Reflectance Distribution Function,pBRDF)未能很好地描述这种现象,为了得到更精确的pBRDF模型,更好地...基于Microfacet理论,当光线照射到粗糙表面时会发生显著的多次镜面反射现象,而传统偏振双向反射分布函数(Polarized Bidirectional Reflectance Distribution Function,pBRDF)未能很好地描述这种现象,为了得到更精确的pBRDF模型,更好地分析材料的偏振特性,本文在包含镜面反射、漫反射和定向漫反射的三分量pBRDF模型基础上,进一步定义了高阶微相位角与一阶相位角的关系。改进后的pBRDF模型不仅考虑了多次镜面反射的几何衰减因子,还引入了微相位角的定义,从而建立了一个更全面的高阶镜面反射pBRDF模型。通过比较不同的pBRDF模型,并结合偏振特性采集装置进行验证,实验结果表明,本文提出的模型优于其他模型,三阶模型效果普遍优于二阶。在偏振图像渲染中,峰值信噪比和结构相似性平均分别提升10.09%和2.97%,呈现更加真实的渲染效果。验证本文提出的高阶镜面反射pBRDF模型能够更准确地描述目标表面的偏振特性。展开更多
文摘This paper presents a trust region algorithm for nonlinear optimization with linear inequality constraints. The global convergence of the algorithm is proved. Local quadratic convergence is obtained for a strong local minimizer.
文摘Acrylic acid was grafted onto the surface of cotton fabric after being short time treated by corona-discharge inair in the presence of initiator.The means of gas-phaseSO<sub>2</sub> derivatization was used along with ESCA to deter-mine corona-discharge-induced-hydroperoxidegroups on the surface.The content of hydroperoxideshows a maxmium value at 15 sec.of corona-dischargetime.Effect of corona treatment time and various con-centration initlator on graft yield was studied.The addit-ion of initiator increases the graft yield.Acceleratedgraft with an increase in the concentration of Mohr’s saltshows that peroxide groups on the corona treated cottonfabric initiate graft copolymerization.
基金supported by the National Council for Technological and Scientific Development of Brazil (RN82/2008)
文摘Multiuser detection can be described as a quadratic optimization problem with binary constraint. Many techniques are available to find approximate solution to this problem. These tech- niques can be characterized in terms of complexity and detection performance. The ＂efficient frontier＂ of known techniques include the decision-feedback, branch-and-bound and probabilistic data association detectors. The presented iterative multiuser detection technique is based on joint deregularized and box-constrained so- lution to quadratic optimization with iterations similar to that used in the nonstationary Tikhonov iterated algorithm. The deregulari- zation maximizes the energy of the solution, this is opposite to the Tikhonov regularization where the energy is minimized. However, combined with box-constraints, the deregularization forces the solution to be close to the binary set. We further exploit the box- constrained dichotomous coordinate descent （DCD） algorithm and adapt it to the nonstationary iterative Tikhonov regularization to present an efficient detector. As a result, the worst-case and aver- age complexity are reduced down to K28 and K2~ floating point operation per second, respectively. The development improves the ＂efficient frontier＂ in multiuser detection, which is illustrated by simulation results. Finally, a field programmable gate array （FPGA） design of the detector is presented. The detection performance obtained from the fixed-point FPGA implementation shows a good match to the floating-point implementation.
文摘融合丰富度、均匀度与差异度的多维测度指标已成为衡量跨学科性的重要工具,然而,针对差异度对应的学科相似性度量方法对跨学科测度的具体影响尚缺乏系统讨论。为此,文章将学科分类层级、归一化系数、引用模式和时间窗口视为学科相似性度量的四个关键要素,通过构建相应的学科相似性矩阵,系统剖析各要素对跨学科测度结果的作用;在不同要素设定下,基于1981—2020年Web of Science收录的研究论文及其参考文献和施引文献数据构建学科相似性矩阵,并选取八本代表性期刊的论文展开实证分析。结果表明:不同层级的学科分类方式对学科相似性度量具有显著影响,进而导致跨学科测度结果存在系统性差异;在4种归一化系数下,运用Ochiai余弦所测得的学科相似性更低、跨学科性区分度更高;在不同引用模式和时间窗口设定下,各学科相似性度量结果对跨学科测度的影响并不显著。
文摘基于Microfacet理论,当光线照射到粗糙表面时会发生显著的多次镜面反射现象,而传统偏振双向反射分布函数(Polarized Bidirectional Reflectance Distribution Function,pBRDF)未能很好地描述这种现象,为了得到更精确的pBRDF模型,更好地分析材料的偏振特性,本文在包含镜面反射、漫反射和定向漫反射的三分量pBRDF模型基础上,进一步定义了高阶微相位角与一阶相位角的关系。改进后的pBRDF模型不仅考虑了多次镜面反射的几何衰减因子,还引入了微相位角的定义,从而建立了一个更全面的高阶镜面反射pBRDF模型。通过比较不同的pBRDF模型,并结合偏振特性采集装置进行验证,实验结果表明,本文提出的模型优于其他模型,三阶模型效果普遍优于二阶。在偏振图像渲染中,峰值信噪比和结构相似性平均分别提升10.09%和2.97%,呈现更加真实的渲染效果。验证本文提出的高阶镜面反射pBRDF模型能够更准确地描述目标表面的偏振特性。
