GNSS广泛地应用于各行各业,但是存在卫星导航信号落地功率低,极易受到各种有意和无意的电磁干扰影响,会对卫星导航应用造成严重的威胁.随着卫星导航的广泛应用,卫星导航信号受干扰问题引起了国际的广泛关注.全球卫星导航系统国际委员会(...GNSS广泛地应用于各行各业,但是存在卫星导航信号落地功率低,极易受到各种有意和无意的电磁干扰影响,会对卫星导航应用造成严重的威胁.随着卫星导航的广泛应用,卫星导航信号受干扰问题引起了国际的广泛关注.全球卫星导航系统国际委员会(International Committee on Global Navigation Satellite Systems,ICG)为此成立了专门的卫星导航干扰检测与削弱(IDM)工作组,旨在开展各国在该领域的政策法规、相关技术及IDM系统建设的研讨与交流.本文介绍和分析了ICG IDM的重要进展及研究态势,并对干扰检测定位理论技术及国内外卫星导航干扰监测系统的研究进展进行了梳理,对深化卫星导航干扰监测的理论与技术研究及保障卫星导航安全具有重要的技术借鉴与研究支撑.展开更多
-Isotope dilution mass spectrometry (IDMS) and ultra-clean room approach are successfully used in the determination of Cd, Pb and Zn in seawater and the sample pretreatment of analysis. The precision in the determinat...-Isotope dilution mass spectrometry (IDMS) and ultra-clean room approach are successfully used in the determination of Cd, Pb and Zn in seawater and the sample pretreatment of analysis. The precision in the determination of Cd, Pb and Zn in seawater is better than±3% and the limits of detection are 6×10-12, 6×10-11 and 2.4×10-10 respectively. The effects of sample pretreatment such as filtration and acidification on the results of determination of Cd- Pb and Zn in seawater are disscussed.展开更多
Quadrature Spatial Modulation (QSM) is a high spectral efficiency Multiple-Input Multiple Output (MIMO) technique used to improve the spectral efficiency of wireless communication systems. The main concept of QSM is t...Quadrature Spatial Modulation (QSM) is a high spectral efficiency Multiple-Input Multiple Output (MIMO) technique used to improve the spectral efficiency of wireless communication systems. The main concept of QSM is to extend the spatial constellation of the conventional Spatial Modulation (SM) in both the in-phase and quadrature components of the data symbol. In this paper, because QSM-based on Interleaxdng Division Multiplexing (IDM) has not been introduced in the literature as a multiple antenna system, we introduced a novel scheme, called QSM system based on Interleaving Division Multiplexing (QSM-IDM). The antenna sets are also applied to a spreader, before being used to assign an antenna number for information transmission. Analysis and simulations for a flat fading channel show that the proposed QSM-IDM method significantly outperforms the original QSM system with the same data rate, while maintaining a relatively acceptable complexity. The obtained simulation results show that the conducted analysis yields significant improvements for the accuracy of the proposed scheme, with satisfactory complexity.展开更多
为研究车辆在换道前与车辆在正常行驶时跟驰行为的差异性,从NGSIM数据库中提取了快速路上的543个换道行为和870个非换道行为的跟驰事件并进行特征分析。使用曼-惠特尼U检验(Mann-Whitney U test)验证了换道前车辆的跟驰行为与正常行驶...为研究车辆在换道前与车辆在正常行驶时跟驰行为的差异性,从NGSIM数据库中提取了快速路上的543个换道行为和870个非换道行为的跟驰事件并进行特征分析。使用曼-惠特尼U检验(Mann-Whitney U test)验证了换道前车辆的跟驰行为与正常行驶的跟驰行为存在显著差异。选取跟驰车辆的车速和车头间距作为性能指标,其均方根百分比误差之和为目标函数,并将目标车道的前车速度纳入到智能驾驶员模型(IDM)中,构建换道准备智能驾驶员跟驰模型(BLC-IDM),利用遗传算法对BLC-IDM进行参数标定和效果验证。研究结果表明,传统的IDM不适用于换道前车辆的跟驰行为,改进后的BLC-IDM拟合精度提高了20%。BLC-IDM可以更加精准地描述车辆换道前的特殊跟驰行为。展开更多
文摘GNSS广泛地应用于各行各业,但是存在卫星导航信号落地功率低,极易受到各种有意和无意的电磁干扰影响,会对卫星导航应用造成严重的威胁.随着卫星导航的广泛应用,卫星导航信号受干扰问题引起了国际的广泛关注.全球卫星导航系统国际委员会(International Committee on Global Navigation Satellite Systems,ICG)为此成立了专门的卫星导航干扰检测与削弱(IDM)工作组,旨在开展各国在该领域的政策法规、相关技术及IDM系统建设的研讨与交流.本文介绍和分析了ICG IDM的重要进展及研究态势,并对干扰检测定位理论技术及国内外卫星导航干扰监测系统的研究进展进行了梳理,对深化卫星导航干扰监测的理论与技术研究及保障卫星导航安全具有重要的技术借鉴与研究支撑.
文摘-Isotope dilution mass spectrometry (IDMS) and ultra-clean room approach are successfully used in the determination of Cd, Pb and Zn in seawater and the sample pretreatment of analysis. The precision in the determination of Cd, Pb and Zn in seawater is better than±3% and the limits of detection are 6×10-12, 6×10-11 and 2.4×10-10 respectively. The effects of sample pretreatment such as filtration and acidification on the results of determination of Cd- Pb and Zn in seawater are disscussed.
文摘Quadrature Spatial Modulation (QSM) is a high spectral efficiency Multiple-Input Multiple Output (MIMO) technique used to improve the spectral efficiency of wireless communication systems. The main concept of QSM is to extend the spatial constellation of the conventional Spatial Modulation (SM) in both the in-phase and quadrature components of the data symbol. In this paper, because QSM-based on Interleaxdng Division Multiplexing (IDM) has not been introduced in the literature as a multiple antenna system, we introduced a novel scheme, called QSM system based on Interleaving Division Multiplexing (QSM-IDM). The antenna sets are also applied to a spreader, before being used to assign an antenna number for information transmission. Analysis and simulations for a flat fading channel show that the proposed QSM-IDM method significantly outperforms the original QSM system with the same data rate, while maintaining a relatively acceptable complexity. The obtained simulation results show that the conducted analysis yields significant improvements for the accuracy of the proposed scheme, with satisfactory complexity.
文摘为研究车辆在换道前与车辆在正常行驶时跟驰行为的差异性,从NGSIM数据库中提取了快速路上的543个换道行为和870个非换道行为的跟驰事件并进行特征分析。使用曼-惠特尼U检验(Mann-Whitney U test)验证了换道前车辆的跟驰行为与正常行驶的跟驰行为存在显著差异。选取跟驰车辆的车速和车头间距作为性能指标,其均方根百分比误差之和为目标函数,并将目标车道的前车速度纳入到智能驾驶员模型(IDM)中,构建换道准备智能驾驶员跟驰模型(BLC-IDM),利用遗传算法对BLC-IDM进行参数标定和效果验证。研究结果表明,传统的IDM不适用于换道前车辆的跟驰行为,改进后的BLC-IDM拟合精度提高了20%。BLC-IDM可以更加精准地描述车辆换道前的特殊跟驰行为。
