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一种离散纵向数据相依结构建模的Cholesky因子模型 被引量:2
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作者 李叶蓁 张伟平 《中国科学技术大学学报》 CAS CSCD 北大核心 2020年第9期1266-1276,共11页
对一类响应变量为离散型的平衡或非平衡纵向数据,提出了均值-相关系数联合回归模型框架,并且使用Cholesky分解方法对模型的相关结构进行参数化,使其具有良好的统计解释性.为了解决似然推断中高维积分计算的难题,提出了一种高效的蒙特卡... 对一类响应变量为离散型的平衡或非平衡纵向数据,提出了均值-相关系数联合回归模型框架,并且使用Cholesky分解方法对模型的相关结构进行参数化,使其具有良好的统计解释性.为了解决似然推断中高维积分计算的难题,提出了一种高效的蒙特卡罗期望最大化(MCEM)算法,并证明了参数估计的渐近性质.模拟实验和实际数据分析表明提出的方法是高度有效的. 展开更多
关键词 离散纵向数据 CHOLESKY分解 均值-相关系数回归模型 蒙特卡罗期望最大化算法
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A Novel 28 GHz Phased Array Antenna for 5G Mobile Communications 被引量:1
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作者 li yezhen REN Yongli +2 位作者 YANG Fan XU Shenheng ZHANG Jiannian 《ZTE Communications》 2020年第3期20-25,共6页
A novel phased array antenna consisting of 256 elements is presented and experimentally verified for 5G millimeter-wave wireless communications.The antenna integrated with a wave control circuit can perform real-time ... A novel phased array antenna consisting of 256 elements is presented and experimentally verified for 5G millimeter-wave wireless communications.The antenna integrated with a wave control circuit can perform real-time beam scanning by reconfiguring the phase of an antenna unit.The unit,designed at 28 GHz using a simple patch structure with one PIN diode,can be electronically controlled to generate 1 bit phase quantization.A prototype of the antenna is fabricated and measured to demonstrate the feasibility of this approach.The measurement results indicate that the antenna achieves high gain and fast beam-steering,with the scan beams within±60°range and the maximum gain up to 21.7 dBi.Furthermore,it is also tested for wireless video transmission.In ZTE Shanghai,the antenna was used for the 5G New Radio(NR)test.The error vector magnitude(EVM)is less than 3%and the adjacent channel leakage ratio(ACLR)less than−35 dBc,which can meet 5G system requirements.Compared with the conventional phased array antenna,the proposed phased array has the advantages of low power consumption,low cost and conformal geometry.Due to these characteristics,the antenna is promising for wide applications in 5G millimeter-wave communication systems. 展开更多
关键词 5G mobile communications millimeter wave phased array antenna
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