针对传统图像识别算法匹配正确率低、运行时间较长等问题,文中提出了基于改进ORB-FLANN(Oriented FAST and Rotated BRIEF-Fast Library for Approximate Nearest Neighbors)的工件图像识别方法。对ORB算法特征描述、图像特征匹配算法...针对传统图像识别算法匹配正确率低、运行时间较长等问题,文中提出了基于改进ORB-FLANN(Oriented FAST and Rotated BRIEF-Fast Library for Approximate Nearest Neighbors)的工件图像识别方法。对ORB算法特征描述、图像特征匹配算法进行修改,解决传统图像识别算法在图像存在尺度和旋转变换情况下存在的弊端并降低误匹配率。该方法对ORB算法检测到的特征点采用SURF(Speeded Up Robust Features)算法添加方向信息并完成特征描述,得到旋转尺度不变性的特征点,结合FLANN算法并引入双向匹配策略进行特征点粗匹配,最后利用渐进采样一致算法进一步剔除误匹配点对完成精匹配。实验结果表明,与其他方法相比,改进算法在处理尺度、旋转等变换图像时,匹配正确率分别提高了2.6%~18.8%和29.5%~43.9%,运行时长均在4 s以内,提高了对工件图像的识别效率和精准性。展开更多
This study aimed to investigate the effects of male hepatitis B virus(HBV)infection on male fertility,embryonic development,and in vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)outcomes.We performed a ...This study aimed to investigate the effects of male hepatitis B virus(HBV)infection on male fertility,embryonic development,and in vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)outcomes.We performed a retrospective cohort study that included 3965 infertile couples who received fresh embryo transfer cycles for the first time at the Fujian Maternity and Child Health Hospital(Fuzhou,China)from January 2018 to January 2021.Infertile couples were categorized based on their HBV infection status into the HBV group(HBV-positive men and HBV-negative women)and the control group(HBV-negative couples).A 1:1 propensity score matching was performed with relatively balanced covariates.Baseline characteristics,semen parameters,laboratory outcomes,clinical outcomes,and obstetric and neonatal outcomes were compared between groups.After propensity score matching,821 couples were included in each group.Both groups had similar semen parameters and obstetric and neonatal outcomes.The HBV group showed a significantly lower live birth rate than the control group(P<0.05).The HBV group had a significantly higher abortion rate than the control group(P<0.05).The rates of high-quality embryos and blastocyst formation were significantly lower in the HBV group than those in the control group(both P<0.05).In conclusion,in couples who undergo IVF/ICSI,male HBV infection reduces the live birth rate and increases the risk of miscarriage.However,the incidence of low birth weight in women with IVF/ICSI does not increase with male HBV infection.展开更多
第5代移动通信系统(5th generation mobile communication system,5G)业务需求的多样性以及各业务场景的典型特性给新空口(new radio,NR)的信道编码技术带来困难及挑战,信道编码方案成为通信业界及学术界的重要研究课题之一。因具备优...第5代移动通信系统(5th generation mobile communication system,5G)业务需求的多样性以及各业务场景的典型特性给新空口(new radio,NR)的信道编码技术带来困难及挑战,信道编码方案成为通信业界及学术界的重要研究课题之一。因具备优越性能,低密度奇偶校验(low-density parity-check,LDPC)码被确定为5G增强移动宽带(enhanced mobile broadband,e MBB)场景数据信道编码方案。在对5G及LDPC码进行概述的基础上,阐述了包括码设计、译码算法、速率匹配和性能评估在内的面向NR的LDPC码标准化工作研究内容。此外,对近年来第3代合作伙伴计划(3rd generation partnership project,3GPP)各成员机构在无线接入网层一(radio access network layer 1,RAN1)标准化工作组历次会议中提出的LDPC码编码方案进行分析和对比,并在此基础上对LDPC码标准化相关工作进行总结。展开更多
文摘针对传统图像识别算法匹配正确率低、运行时间较长等问题,文中提出了基于改进ORB-FLANN(Oriented FAST and Rotated BRIEF-Fast Library for Approximate Nearest Neighbors)的工件图像识别方法。对ORB算法特征描述、图像特征匹配算法进行修改,解决传统图像识别算法在图像存在尺度和旋转变换情况下存在的弊端并降低误匹配率。该方法对ORB算法检测到的特征点采用SURF(Speeded Up Robust Features)算法添加方向信息并完成特征描述,得到旋转尺度不变性的特征点,结合FLANN算法并引入双向匹配策略进行特征点粗匹配,最后利用渐进采样一致算法进一步剔除误匹配点对完成精匹配。实验结果表明,与其他方法相比,改进算法在处理尺度、旋转等变换图像时,匹配正确率分别提高了2.6%~18.8%和29.5%~43.9%,运行时长均在4 s以内,提高了对工件图像的识别效率和精准性。
基金the innovation Platform Project of Science and Technology,Fujian Province(2021Y2012)the Key Project on the Integration of Industry,Education and Research Collaborative Innovation of Fujian Province(No.2021YZ034011)+2 种基金the Key Project on Science and Technology Program of Fujian Health Commission(No.2021ZD01002)the Fujian Provincial Health and Young and Middle-aged Key Personnel Training Program(No.2022GGA035)the Natural Science Foundation of Fujian Province(No.2023J011221).
文摘This study aimed to investigate the effects of male hepatitis B virus(HBV)infection on male fertility,embryonic development,and in vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)outcomes.We performed a retrospective cohort study that included 3965 infertile couples who received fresh embryo transfer cycles for the first time at the Fujian Maternity and Child Health Hospital(Fuzhou,China)from January 2018 to January 2021.Infertile couples were categorized based on their HBV infection status into the HBV group(HBV-positive men and HBV-negative women)and the control group(HBV-negative couples).A 1:1 propensity score matching was performed with relatively balanced covariates.Baseline characteristics,semen parameters,laboratory outcomes,clinical outcomes,and obstetric and neonatal outcomes were compared between groups.After propensity score matching,821 couples were included in each group.Both groups had similar semen parameters and obstetric and neonatal outcomes.The HBV group showed a significantly lower live birth rate than the control group(P<0.05).The HBV group had a significantly higher abortion rate than the control group(P<0.05).The rates of high-quality embryos and blastocyst formation were significantly lower in the HBV group than those in the control group(both P<0.05).In conclusion,in couples who undergo IVF/ICSI,male HBV infection reduces the live birth rate and increases the risk of miscarriage.However,the incidence of low birth weight in women with IVF/ICSI does not increase with male HBV infection.
