This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passi...This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passive sensing scheme.The scheme is based on the radio frequency(RF)fingerprint learning of the RF radio unit(RRU)to build an RF fingerprint library of RRUs.The source RRU is identified by comparing the RF fingerprints carried by the signal at the receiver side.The receiver extracts the channel parameters from the signal and estimates the channel environment,thus locating the reflectors in the environment.The proposed scheme can effectively solve the problem of interference between signals in the same time-frequency domain but in different spatial domains when multiple RRUs jointly serve users in CF-RAN architecture.Simulation results show that the proposed passive ISAC scheme can effectively detect reflector location information in the environment without degrading the communication performance.展开更多
目的系统评价严重创伤患者发重症监护后综合征(PICS)的危险因素。方法计算机检索PubMed、Medline、Web of Science、CochraneLibrary、中国知网、万方数据知识服务平台、维普网、中国生物医学文献数据库中关于严重创伤患者发生PICS危险...目的系统评价严重创伤患者发重症监护后综合征(PICS)的危险因素。方法计算机检索PubMed、Medline、Web of Science、CochraneLibrary、中国知网、万方数据知识服务平台、维普网、中国生物医学文献数据库中关于严重创伤患者发生PICS危险因素的相关文献,检索时间限定为2010年1月至2024年4月。由2名研究者独立进行文献的筛选与数据提取,采用纽卡斯尔-渥太华量表(NOS)对纳入的队列研究和病例对照研究进行文献质量评价,横断面研究则参照美国卫生保健和质量机构(AHRQ)的标准进行文献质量评价,采用RevMan 5.4和Stata18.0软件进行meta分析。结果共纳入11篇文献,其中7篇为横断面研究,4篇为病例对照研究,文献质量均为中高等。meta分析结果显示,年龄≥60岁(OR=1.66,95%CI:1.43~1.91,P<0.001)、吸烟(OR=5.45,95%CI:1.61~18.47,P=0.006)、饮酒(OR=6.90,95%CI:2.14~22.26,P=0.001)、入住ICU时长≥7 d(OR=2.45,95%CI:1.18~5.11,P=0.020)、机械通气治疗(OR=1.96,95%CI:1.04~3.68,P=0.040)、睡眠障碍(OR=2.78,95%CI:1.35~5.73,P=0.005)、镇静药物使用(OR=2.88,95%CI:1.34~6.22,P=0.007)是严重创伤患者发生PICS的独立危险因素。敏感性和发表偏倚分析结果显示,除年龄≥60岁和入住ICU时长≥7 d因素外,其他因素均提示分析结果可靠,存在发表偏倚可能较小。结论严重创伤患者发生ICU后综合征的危险因素众多,临床实践中医护人员应重点关注其高危人群,并对这些风险因素进行及时的评估和干预,以降低重症创伤患者ICU后综合征的发生率,更好地促进患者健康转归。展开更多
In this paper,we investigate networkassisted full-duplex(NAFD)cell-free millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems with digital-to-analog converter(DAC)quantization and fronthaul compre...In this paper,we investigate networkassisted full-duplex(NAFD)cell-free millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems with digital-to-analog converter(DAC)quantization and fronthaul compression.We propose to maximize the weighted uplink and downlink sum rate by jointly optimizing the power allocation of both the transmitting remote antenna units(T-RAUs)and uplink users and the variances of the downlink and uplink fronthaul compression noises.To deal with this challenging problem,we further apply a successive convex approximation(SCA)method to handle the non-convex bidirectional limited-capacity fronthaul constraints.The simulation results verify the convergence of the proposed SCA-based algorithm and analyze the impact of fronthaul capacity and DAC quantization on the spectral efficiency of the NAFD cell-free mmWave massive MIMO systems.Moreover,some insightful conclusions are obtained through the comparisons of spectral efficiency,which shows that NAFD achieves better performance gains than cotime co-frequency full-duplex cloud radio access network(CCFD C-RAN)in the cases of practical limited-resolution DACs.Specifically,their performance gaps with 8-bit DAC quantization are larger than that with1-bit DAC quantization,which attains a 5.5-fold improvement.展开更多
基于欧洲中期天气预报中心(ECMWF)、中国气象局(CMA)、日本气象厅(JMA)、美国国家环境预报中心(NCEP)、英国气象局(UKMO)五个模式集成的交互式全球大集合预报系统(THORPEX Interactive Grand Global Ensemble,简称TIGGE)资料集的确定性...基于欧洲中期天气预报中心(ECMWF)、中国气象局(CMA)、日本气象厅(JMA)、美国国家环境预报中心(NCEP)、英国气象局(UKMO)五个模式集成的交互式全球大集合预报系统(THORPEX Interactive Grand Global Ensemble,简称TIGGE)资料集的确定性预报、集合预报以及地面降水观测数据,采用多模式集成平均(EMN)、消除偏差集成平均(BREM)、滑动训练期超级集合方法(R_SUP)对2018年华南汛期(4—9月)粤港澳大湾区的降水预报开展了评估检验。总体而言,多模式集成预报方法在大湾区前汛期降水预报的均方根误差平均比后汛期高2 mm;多模式集成预报方法的预报能力在前汛期随着预报时效的延长而呈持续下降趋势,后汛期则表现为短期(24~72 h)下降、中期(72~168 h)持续平稳的变化特点。与预先的假设差异主要表现在:对前、后汛期的降水预报综合表现最好的均是数学原理相对简单的EMN,而BREM和R_SUP的空间平均评分指标则稍差,但其在降水落区预报中仍有较好的预报技巧。展开更多
介绍基于UMAC(Universal Motion and Automation Controller)先进技术的精密伺服控制系统,并以公司正在量产的国内唯一模组封装设备控制系统为例,介绍该系统的设计方案。最终调试结果表明,UMAC控制器在高精度、高响应、快速、灵活和开...介绍基于UMAC(Universal Motion and Automation Controller)先进技术的精密伺服控制系统,并以公司正在量产的国内唯一模组封装设备控制系统为例,介绍该系统的设计方案。最终调试结果表明,UMAC控制器在高精度、高响应、快速、灵活和开放性的精密激光加工控制系统中具有广阔的应用前景。展开更多
基金supported in part by the National Key Research and Development Program under Grant(2021YFB2900300)by the National Natural Science Foundation of China(NSFC)under Grants 61971127,61871122by the Southeast University-China Mobile Research Institute Joint Innovation Center,and by the Major Key Project of PCL(PCL2021A01-2).
文摘This paper investigates how to achieve integrated sensing and communication(ISAC)based on a cell-free radio access network(CF-RAN)architecture with a minimum footprint of communication resources.We propose a new passive sensing scheme.The scheme is based on the radio frequency(RF)fingerprint learning of the RF radio unit(RRU)to build an RF fingerprint library of RRUs.The source RRU is identified by comparing the RF fingerprints carried by the signal at the receiver side.The receiver extracts the channel parameters from the signal and estimates the channel environment,thus locating the reflectors in the environment.The proposed scheme can effectively solve the problem of interference between signals in the same time-frequency domain but in different spatial domains when multiple RRUs jointly serve users in CF-RAN architecture.Simulation results show that the proposed passive ISAC scheme can effectively detect reflector location information in the environment without degrading the communication performance.
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grants 61971127,61871465,61871122in part by the National Key Research and Development Program under Grant 2020YFB1806600in part by the open research fund of National Mobile Communications Research Laboratory,Southeast University under Grant 2022D11。
文摘In this paper,we investigate networkassisted full-duplex(NAFD)cell-free millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems with digital-to-analog converter(DAC)quantization and fronthaul compression.We propose to maximize the weighted uplink and downlink sum rate by jointly optimizing the power allocation of both the transmitting remote antenna units(T-RAUs)and uplink users and the variances of the downlink and uplink fronthaul compression noises.To deal with this challenging problem,we further apply a successive convex approximation(SCA)method to handle the non-convex bidirectional limited-capacity fronthaul constraints.The simulation results verify the convergence of the proposed SCA-based algorithm and analyze the impact of fronthaul capacity and DAC quantization on the spectral efficiency of the NAFD cell-free mmWave massive MIMO systems.Moreover,some insightful conclusions are obtained through the comparisons of spectral efficiency,which shows that NAFD achieves better performance gains than cotime co-frequency full-duplex cloud radio access network(CCFD C-RAN)in the cases of practical limited-resolution DACs.Specifically,their performance gaps with 8-bit DAC quantization are larger than that with1-bit DAC quantization,which attains a 5.5-fold improvement.
文摘基于欧洲中期天气预报中心(ECMWF)、中国气象局(CMA)、日本气象厅(JMA)、美国国家环境预报中心(NCEP)、英国气象局(UKMO)五个模式集成的交互式全球大集合预报系统(THORPEX Interactive Grand Global Ensemble,简称TIGGE)资料集的确定性预报、集合预报以及地面降水观测数据,采用多模式集成平均(EMN)、消除偏差集成平均(BREM)、滑动训练期超级集合方法(R_SUP)对2018年华南汛期(4—9月)粤港澳大湾区的降水预报开展了评估检验。总体而言,多模式集成预报方法在大湾区前汛期降水预报的均方根误差平均比后汛期高2 mm;多模式集成预报方法的预报能力在前汛期随着预报时效的延长而呈持续下降趋势,后汛期则表现为短期(24~72 h)下降、中期(72~168 h)持续平稳的变化特点。与预先的假设差异主要表现在:对前、后汛期的降水预报综合表现最好的均是数学原理相对简单的EMN,而BREM和R_SUP的空间平均评分指标则稍差,但其在降水落区预报中仍有较好的预报技巧。
文摘介绍基于UMAC(Universal Motion and Automation Controller)先进技术的精密伺服控制系统,并以公司正在量产的国内唯一模组封装设备控制系统为例,介绍该系统的设计方案。最终调试结果表明,UMAC控制器在高精度、高响应、快速、灵活和开放性的精密激光加工控制系统中具有广阔的应用前景。
