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基于可变时隙的PPM激光数据传输技术研究 被引量:7
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作者 顾剑飞 何宁 廖欣 《光通信技术》 北大核心 2018年第7期14-16,共3页
针对无线光通信在开放信道传输环境的安全性和可靠性要求,提出一种可变时隙的脉冲位置调制(PPM)信号传输方法。研究了PPM编码调制原理与信息分帧技术,分析了导频与单字节组成PPM帧编解码过程,并通过软硬件方法完成了系统设计,以短帧形... 针对无线光通信在开放信道传输环境的安全性和可靠性要求,提出一种可变时隙的脉冲位置调制(PPM)信号传输方法。研究了PPM编码调制原理与信息分帧技术,分析了导频与单字节组成PPM帧编解码过程,并通过软硬件方法完成了系统设计,以短帧形式实现可变时隙信息传输,减小信息丢失概率,进一步提升无线光信号传输性能。实验测试证明,可变时隙PPM的数据传输通信灵活方便,收发双方通过设定可变时隙的PPM通信协议,进一步提高了抗干扰和抗截获等性能。 展开更多
关键词 激光通信 可变时隙 脉冲位置调制 导行码
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Evaluation of driving behavior based on massive vehicle trajectory data 被引量:9
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作者 Sun Chao Chen Xiaohong +1 位作者 Zhang H.Michael Zhang Junfeng 《Journal of Southeast University(English Edition)》 EI CAS 2019年第4期502-508,共7页
Based on the driver surveillance video data and controller area network(CAN)data,the methods of studying commercial vehicles’driving behavior is relatively advanced.However,these methods have difficulty in covering p... Based on the driver surveillance video data and controller area network(CAN)data,the methods of studying commercial vehicles’driving behavior is relatively advanced.However,these methods have difficulty in covering private vehicles.Naturalistic driving studies have disadvantages of small sample size and high cost,one new driving behavior evaluation method using massive vehicle trajectory data is put forward.An automatic encoding machine is used to reduce the noise of raw data,and then driving dynamics and self-organizing mapping(SOM)classification are used to give thresholds or the judgement method of overspeed,rapid speed change,rapid turning and rapid lane changing.The proportion of different driving behaviors and typical dangerous driving behaviors is calculated,then the temporal and spatial distribution of drivers’driving behavior and the driving behavior characteristics on typical roads are analyzed.Driving behaviors on accident-prone road sections and normal road sections are compared.Results show that in Shenzhen,frequent lane changing and overspeed are the most common unsafe driving behaviors;16.1%drivers have relatively aggressive driving behavior;the proportion of dangerous driving behavior is higher outside the original economic special zone;dangerous driving behavior is highly correlated with traffic accident frequency. 展开更多
关键词 driving behavior global positioning system(GPS)navigating data automatic coding machine self-organizing mapping(SOM)
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