随着卫星通信技术的迅速发展,卫星互联网已成为现代通信的重要组成部分。机载卫星通信终端及其核心组件的性能直接决定了通信系统的效率与可靠性。目前,这些关键组件的研发主要由国外企业垄断,限制了技术的发展并且成本高昂。通过对比5G...随着卫星通信技术的迅速发展,卫星互联网已成为现代通信的重要组成部分。机载卫星通信终端及其核心组件的性能直接决定了通信系统的效率与可靠性。目前,这些关键组件的研发主要由国外企业垄断,限制了技术的发展并且成本高昂。通过对比5G NR NTN和DVB-S2X/RCS2两种主流卫星通信体制,总结出卫通终端的功能性能指标,并结合机载环境下的需求,分析了典型卫通终端协议模块的架构和指标。最后,研究总结了基于5G NR和DVB标准的测试指标及方法,以提高测试效能,并实现产品的实时自检应用。展开更多
To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is deve...To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is developed to identify the geometric parameters.The study utilizes a common precast element for highway bridges as the research subject.First,edge feature points of the bridge component section are extracted from images of the precast component cross-sections by combining the Canny operator with mathematical morphology.Subsequently,a deep learning model is developed to identify the geometric parameters of the precast components using the extracted edge coordinates from the images as input and the predefined control parameters of the bridge section as output.A dataset is generated by varying the control parameters and noise levels for model training.Finally,field measurements are conducted to validate the accuracy of the developed method.The results indicate that the developed method effectively identifies the geometric parameters of bridge precast components,with an error rate maintained within 5%.展开更多
BACKGROUND Intrathecal bupivacaine is the traditional anesthetic drug used in spinal anesthesia for caesarean sections(CSs),but ropivacaine has emerged as a potential alter-native.This meta-analysis compares the effic...BACKGROUND Intrathecal bupivacaine is the traditional anesthetic drug used in spinal anesthesia for caesarean sections(CSs),but ropivacaine has emerged as a potential alter-native.This meta-analysis compares the efficacy and safety of intrathecal hyper-baric bupivacaine vs hyperbaric ropivacaine for cesarean sections.AIM To systematically evaluate and compare the efficacy and safety of intrathecal hyperbaric bupivacaine and hyperbaric ropivacaine for spinal anesthesia in CSs.METHODS A thorough search of electronic databases was carried out to find pertinent randomized controlled trials(RCTs)comparing intrathecal hyperbaric ropi-vacaine and hyperbaric bupivacaine during CSs.PubMed,Cochrane database,Google Scholar,and Scopus were searched,and papers from January 2000 to January 2024 were deemed eligible and filtered using predetermined inclusion and exclusion criteria.Studies were assessed for methodological quality,and data were extracted for time to adequate anesthesia(sensory and motor blockade),duration of sensory and motor block,hemodynamic changes and side effect profile.The standardized mean difference with 95%CI was used for continuous data.Dichotomous variables were assessed using the Mantel-Haenszel test and the random effect model to compute the odds ratio.RESULTS Total 8 RCTs were selected from a pool of 119 search results for meta-analysis.The meta-analysis evaluated pooled effect sizes and assessed heterogeneity among the studies.The primary objective was to compare key outcomes to identify any significant variances in efficacy and safety profiles between two local anesthetics.The analysis revealed that the difference in the onset of sensory blockade between the two local anesthetics was statistically insignificant(P=0.1586).However,the onset of motor blockade appeared to be faster with bupivacaine(P=0.03589).Additionally,the regression of sensory and motor blockade occurred earlier in the ropivacaine group.Furthermore,the duration of the first analgesic effect was shorter with a significance level of P<0.05.Regarding side effects profile,including hypotension,nausea,and shivering,the study did not observe any significant differences between the two groups.CONCLUSION This meta-analysis offers insights into the effectiveness and safety of hyperbaric bupivacaine vs ropivacaine for cesarean sections.Hyperbaric ropivacaine had a comparable safety profile and faster regression of sensory and motor blockade than hyperbaric bupivacaine,perhaps aiding early mobilization of parturient and facilitating mother-child bonding.Choosing ropivacaine may offer benefits beyond efficacy for cesarean section patients and short surgical procedures.展开更多
文摘随着卫星通信技术的迅速发展,卫星互联网已成为现代通信的重要组成部分。机载卫星通信终端及其核心组件的性能直接决定了通信系统的效率与可靠性。目前,这些关键组件的研发主要由国外企业垄断,限制了技术的发展并且成本高昂。通过对比5G NR NTN和DVB-S2X/RCS2两种主流卫星通信体制,总结出卫通终端的功能性能指标,并结合机载环境下的需求,分析了典型卫通终端协议模块的架构和指标。最后,研究总结了基于5G NR和DVB标准的测试指标及方法,以提高测试效能,并实现产品的实时自检应用。
基金The National Natural Science Foundation of China(No.52338011,52378291)Young Elite Scientists Sponsorship Program by CAST(No.2022-2024QNRC0101).
文摘To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is developed to identify the geometric parameters.The study utilizes a common precast element for highway bridges as the research subject.First,edge feature points of the bridge component section are extracted from images of the precast component cross-sections by combining the Canny operator with mathematical morphology.Subsequently,a deep learning model is developed to identify the geometric parameters of the precast components using the extracted edge coordinates from the images as input and the predefined control parameters of the bridge section as output.A dataset is generated by varying the control parameters and noise levels for model training.Finally,field measurements are conducted to validate the accuracy of the developed method.The results indicate that the developed method effectively identifies the geometric parameters of bridge precast components,with an error rate maintained within 5%.
文摘BACKGROUND Intrathecal bupivacaine is the traditional anesthetic drug used in spinal anesthesia for caesarean sections(CSs),but ropivacaine has emerged as a potential alter-native.This meta-analysis compares the efficacy and safety of intrathecal hyper-baric bupivacaine vs hyperbaric ropivacaine for cesarean sections.AIM To systematically evaluate and compare the efficacy and safety of intrathecal hyperbaric bupivacaine and hyperbaric ropivacaine for spinal anesthesia in CSs.METHODS A thorough search of electronic databases was carried out to find pertinent randomized controlled trials(RCTs)comparing intrathecal hyperbaric ropi-vacaine and hyperbaric bupivacaine during CSs.PubMed,Cochrane database,Google Scholar,and Scopus were searched,and papers from January 2000 to January 2024 were deemed eligible and filtered using predetermined inclusion and exclusion criteria.Studies were assessed for methodological quality,and data were extracted for time to adequate anesthesia(sensory and motor blockade),duration of sensory and motor block,hemodynamic changes and side effect profile.The standardized mean difference with 95%CI was used for continuous data.Dichotomous variables were assessed using the Mantel-Haenszel test and the random effect model to compute the odds ratio.RESULTS Total 8 RCTs were selected from a pool of 119 search results for meta-analysis.The meta-analysis evaluated pooled effect sizes and assessed heterogeneity among the studies.The primary objective was to compare key outcomes to identify any significant variances in efficacy and safety profiles between two local anesthetics.The analysis revealed that the difference in the onset of sensory blockade between the two local anesthetics was statistically insignificant(P=0.1586).However,the onset of motor blockade appeared to be faster with bupivacaine(P=0.03589).Additionally,the regression of sensory and motor blockade occurred earlier in the ropivacaine group.Furthermore,the duration of the first analgesic effect was shorter with a significance level of P<0.05.Regarding side effects profile,including hypotension,nausea,and shivering,the study did not observe any significant differences between the two groups.CONCLUSION This meta-analysis offers insights into the effectiveness and safety of hyperbaric bupivacaine vs ropivacaine for cesarean sections.Hyperbaric ropivacaine had a comparable safety profile and faster regression of sensory and motor blockade than hyperbaric bupivacaine,perhaps aiding early mobilization of parturient and facilitating mother-child bonding.Choosing ropivacaine may offer benefits beyond efficacy for cesarean section patients and short surgical procedures.
