Frequency-invariant beamformer (FIB) design is a key issue in wideband array signal processing. To use commonly wideband linear array with tapped delay line (TDL) structure and complex weights, the FIB design is p...Frequency-invariant beamformer (FIB) design is a key issue in wideband array signal processing. To use commonly wideband linear array with tapped delay line (TDL) structure and complex weights, the FIB design is provided according to the rule of minimizing the sidelobe level of the beampattern at the reference frequency while keeping the distortionless response constraint in the mainlobe direction at the reference frequency, the norm constraint of the weight vector and the amplitude constraint of the averaged spatial response variation (SRV). This kind of beamformer design problem can be solved with the interior-point method after being converted to the form of standard second order cone programming (SOCP). The computer simulations are presented which illustrate the effectiveness of our FIB design method for the wideband linear array with TDL structure and complex weights.展开更多
单一线性锥规划方法求解最优潮流(optimal power flow,OPF)问题时,锥变量仅局限于某个单一锥集合,使得锥规划模型的构造缺乏灵活性,建模难度较大。为此,基于混合线性锥规划(mixed cone linear programming,MCLP)方法,提出了求解OPF问题...单一线性锥规划方法求解最优潮流(optimal power flow,OPF)问题时,锥变量仅局限于某个单一锥集合,使得锥规划模型的构造缺乏灵活性,建模难度较大。为此,基于混合线性锥规划(mixed cone linear programming,MCLP)方法,提出了求解OPF问题的3种MCLP模型—MCLP-OPF。该模型采用不同的锥变量来构建原始OPF问题的锥松弛模型,锥变量可同时取自半正定锥、二阶锥和非负多面体锥。引入MCLP-OPF问题的可行域"厚度",并根据该"厚度"大小选择直接内点法或齐次自对偶(homogeneous self-dual,HSD)内点法求解。从C-703节点等6个测试系统的仿真结果可以看到,相较于半定规划法,MCLP-OPF提高了锥规划方法的建模效率、求解效率和存储效率,更适于求解大规模电力系统问题。展开更多
For geotechnical stability analysis involving the Drucker-Prager(DP)criterion,both the c-ϕreduction scheme and the M-K reduction scheme can be utilized.With the aid of the second-order cone programming optimized finit...For geotechnical stability analysis involving the Drucker-Prager(DP)criterion,both the c-ϕreduction scheme and the M-K reduction scheme can be utilized.With the aid of the second-order cone programming optimized finite element method(FEM-SOCP),a comparison of the two strength reduction schemes for the stability analysis of a homogeneous slope and a multilayered slope is carried out.Numerical investigations disclose that the FoS results calculated by the c-ϕreduction scheme agree well with those calculated by the classical Morgenstern-Price solutions.However,the FoS results attained by the M-K reduction scheme may lead to conservative estimation of the geotechnical safety,particularly for the cases with large internal friction angles.In view of the possible big difference in stability analysis results caused by the M-K reduction scheme,the c-ϕreduction scheme is recommended for the geotechnical stability analyses involving the DP criterion.展开更多
基金supported by the President Award of Chinese Academy of Sciences (O729031511)
文摘Frequency-invariant beamformer (FIB) design is a key issue in wideband array signal processing. To use commonly wideband linear array with tapped delay line (TDL) structure and complex weights, the FIB design is provided according to the rule of minimizing the sidelobe level of the beampattern at the reference frequency while keeping the distortionless response constraint in the mainlobe direction at the reference frequency, the norm constraint of the weight vector and the amplitude constraint of the averaged spatial response variation (SRV). This kind of beamformer design problem can be solved with the interior-point method after being converted to the form of standard second order cone programming (SOCP). The computer simulations are presented which illustrate the effectiveness of our FIB design method for the wideband linear array with TDL structure and complex weights.
文摘单一线性锥规划方法求解最优潮流(optimal power flow,OPF)问题时,锥变量仅局限于某个单一锥集合,使得锥规划模型的构造缺乏灵活性,建模难度较大。为此,基于混合线性锥规划(mixed cone linear programming,MCLP)方法,提出了求解OPF问题的3种MCLP模型—MCLP-OPF。该模型采用不同的锥变量来构建原始OPF问题的锥松弛模型,锥变量可同时取自半正定锥、二阶锥和非负多面体锥。引入MCLP-OPF问题的可行域"厚度",并根据该"厚度"大小选择直接内点法或齐次自对偶(homogeneous self-dual,HSD)内点法求解。从C-703节点等6个测试系统的仿真结果可以看到,相较于半定规划法,MCLP-OPF提高了锥规划方法的建模效率、求解效率和存储效率,更适于求解大规模电力系统问题。
基金Projects(42002277,41972279,41772291)supported by the National Natural Science Foundation of ChinaProjects(2020M680321,2021T140046)supported by the China Postdoctoral Science Foundation+1 种基金Projects(2020-zz-081,2021-PC-003)supported by the Beijing Postdoctoral Research Foundation,ChinaProject(X21074)supported by the Fundamental Research Funds for Beijing University of Civil Engineering and Architecture,China。
文摘For geotechnical stability analysis involving the Drucker-Prager(DP)criterion,both the c-ϕreduction scheme and the M-K reduction scheme can be utilized.With the aid of the second-order cone programming optimized finite element method(FEM-SOCP),a comparison of the two strength reduction schemes for the stability analysis of a homogeneous slope and a multilayered slope is carried out.Numerical investigations disclose that the FoS results calculated by the c-ϕreduction scheme agree well with those calculated by the classical Morgenstern-Price solutions.However,the FoS results attained by the M-K reduction scheme may lead to conservative estimation of the geotechnical safety,particularly for the cases with large internal friction angles.In view of the possible big difference in stability analysis results caused by the M-K reduction scheme,the c-ϕreduction scheme is recommended for the geotechnical stability analyses involving the DP criterion.