Orthogonal frequency division multiplexing passive optical network(OFDM-PON) has superior anti-dispersion property to operate in the C-band of fiber for increased optical power budget. However,the downlink broadcast e...Orthogonal frequency division multiplexing passive optical network(OFDM-PON) has superior anti-dispersion property to operate in the C-band of fiber for increased optical power budget. However,the downlink broadcast exposes the physical layer vulnerable to the threat of illegal eavesdropping. Quantum noise stream cipher(QNSC) is a classic physical layer encryption method and well compatible with the OFDM-PON. Meanwhile, it is indispensable to exploit forward error correction(FEC) to control errors in data transmission. However, when QNSC and FEC are jointly coded, the redundant information becomes heavier and thus the code rate of the transmitted signal will be largely reduced. In this work, we propose a physical layer encryption scheme based on polar-code-assisted QNSC. In order to improve the code rate and security of the transmitted signal, we exploit chaotic sequences to yield the redundant bits and utilize the redundant information of the polar code to generate the higher-order encrypted signal in the QNSC scheme with the operation of the interleaver.We experimentally demonstrate the encrypted 16/64-QAM, 16/256-QAM, 16/1024-QAM, 16/4096-QAM QNSC signals transmitted over 30-km standard single mode fiber. For the transmitted 16/4096-QAM QNSC signal, compared with the conventional QNSC method, the proposed method increases the code rate from 0.1 to 0.32 with enhanced security.展开更多
目的 比较腹腔镜全胃D2根治术与开腹手术治疗胃上部癌的临床效果。方法选取2017年6月至2018年2月濮阳市惠民医院收治的104例胃上部癌患者,按照随机数字表分为研究组与对照组各52例。研究组采取腹腔镜全胃D2根治术,对照组采取传统开腹手...目的 比较腹腔镜全胃D2根治术与开腹手术治疗胃上部癌的临床效果。方法选取2017年6月至2018年2月濮阳市惠民医院收治的104例胃上部癌患者,按照随机数字表分为研究组与对照组各52例。研究组采取腹腔镜全胃D2根治术,对照组采取传统开腹手术,比较两组的治疗结果及术后并发症发生情况。结果研究组手术时间长于对照组[(4.43±1.37)h vs.(3.85±1.30)h],差异有统计学意义( P = 0.029),但切口长度[(5.16±1.70)cm vs.(17.04±2.68)cm]、出血量[(155.36± 12.58)ml vs.(307.26±14.55)ml]、胃肠功能恢复时间[(3.82±1.26)d vs.(4.40±1.45)d]、首次进食时间[(5.07±1.55)d vs.(5.83±1.72)d]及住院时间[(10.81±3.13)d vs.(12.75±3.79)d]均小于对照组,差异有统计学意义( P < 0.05)。两组的淋巴结清扫数量差异无统计学意义( P > 0.05)。治疗前两组的躯体症状、心理症状、生理症状及睡眠质量评分无显著差别( P > 0.05),治疗后,研究组上述各项评分均高于对照组( P < 0.05);研究组术后并发症发生率低于对照组(5.77% vs. 17.31%,χ^2=6.523, P < 0.05);术后6个月,研究组的生存率为96.15%(50/52),对照组的生存率为98.08%(51/52),两组生存率差异无统计学意义(χ^2=0.343, P > 0.05)。结论胃上部癌患者采取腹腔镜全胃D2根治术可取得与传统开腹手术同样的根治效果,同时可明显缩短住院时间,利于病情快速恢复,改善生活质量,减少并发症发生率,安全性高。展开更多
基金supported in part by the National Natural Science Foundation of China Project under Grant 62075147the Suzhou Industry Technological Innovation Projects under Grant SYG202348.
文摘Orthogonal frequency division multiplexing passive optical network(OFDM-PON) has superior anti-dispersion property to operate in the C-band of fiber for increased optical power budget. However,the downlink broadcast exposes the physical layer vulnerable to the threat of illegal eavesdropping. Quantum noise stream cipher(QNSC) is a classic physical layer encryption method and well compatible with the OFDM-PON. Meanwhile, it is indispensable to exploit forward error correction(FEC) to control errors in data transmission. However, when QNSC and FEC are jointly coded, the redundant information becomes heavier and thus the code rate of the transmitted signal will be largely reduced. In this work, we propose a physical layer encryption scheme based on polar-code-assisted QNSC. In order to improve the code rate and security of the transmitted signal, we exploit chaotic sequences to yield the redundant bits and utilize the redundant information of the polar code to generate the higher-order encrypted signal in the QNSC scheme with the operation of the interleaver.We experimentally demonstrate the encrypted 16/64-QAM, 16/256-QAM, 16/1024-QAM, 16/4096-QAM QNSC signals transmitted over 30-km standard single mode fiber. For the transmitted 16/4096-QAM QNSC signal, compared with the conventional QNSC method, the proposed method increases the code rate from 0.1 to 0.32 with enhanced security.
文摘目的 比较腹腔镜全胃D2根治术与开腹手术治疗胃上部癌的临床效果。方法选取2017年6月至2018年2月濮阳市惠民医院收治的104例胃上部癌患者,按照随机数字表分为研究组与对照组各52例。研究组采取腹腔镜全胃D2根治术,对照组采取传统开腹手术,比较两组的治疗结果及术后并发症发生情况。结果研究组手术时间长于对照组[(4.43±1.37)h vs.(3.85±1.30)h],差异有统计学意义( P = 0.029),但切口长度[(5.16±1.70)cm vs.(17.04±2.68)cm]、出血量[(155.36± 12.58)ml vs.(307.26±14.55)ml]、胃肠功能恢复时间[(3.82±1.26)d vs.(4.40±1.45)d]、首次进食时间[(5.07±1.55)d vs.(5.83±1.72)d]及住院时间[(10.81±3.13)d vs.(12.75±3.79)d]均小于对照组,差异有统计学意义( P < 0.05)。两组的淋巴结清扫数量差异无统计学意义( P > 0.05)。治疗前两组的躯体症状、心理症状、生理症状及睡眠质量评分无显著差别( P > 0.05),治疗后,研究组上述各项评分均高于对照组( P < 0.05);研究组术后并发症发生率低于对照组(5.77% vs. 17.31%,χ^2=6.523, P < 0.05);术后6个月,研究组的生存率为96.15%(50/52),对照组的生存率为98.08%(51/52),两组生存率差异无统计学意义(χ^2=0.343, P > 0.05)。结论胃上部癌患者采取腹腔镜全胃D2根治术可取得与传统开腹手术同样的根治效果,同时可明显缩短住院时间,利于病情快速恢复,改善生活质量,减少并发症发生率,安全性高。
