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BIM技术赋能在役桥梁安全与高效运维 被引量:2
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作者 张丽萍 王广 +2 位作者 王力 陈云峰 李子奇 《中国安全生产科学技术》 北大核心 2025年第1期101-108,共8页
为了保证运维阶段桥梁结构安全,提升桥梁运维工作的效率,开展公路混凝土梁式桥运维阶段建筑信息模型(building information modeling,BIM)技术应用研究。在对公路桥梁现行编码体系进行扩展的基础上,提出1种参数化快速建模方法,以快速完... 为了保证运维阶段桥梁结构安全,提升桥梁运维工作的效率,开展公路混凝土梁式桥运维阶段建筑信息模型(building information modeling,BIM)技术应用研究。在对公路桥梁现行编码体系进行扩展的基础上,提出1种参数化快速建模方法,以快速完成桥梁构件族的创建与整体模型的集成。借助Autodesk Revit软件应用程序编程接口(application programming interface,API),采用C#语言,开发公路混凝土梁式桥智慧运维状态评估系统,以实际工程应用进行验证分析。研究结果表明:全面统一的桥梁信息编码体系,能够提高桥梁信息统计与检索效率;提出的快速建模方法能够显著减少建模工作量,建模时间较传统建模方法可减少60%,并保证模型的准确性与规范性;运维状态评估系统能够实现养护数据的充分利用与桥梁评定工作的自动化,通过对桥梁运维信息的有效组织,实现服役性能的长期追踪,从而确保运营期桥梁结构状态安全稳定。研究结果可为公路混凝土梁式桥运维管理提供技术支撑,提升桥梁运维的数字化水平。 展开更多
关键词 桥梁工程 运维状态评估系统 Building Information Modeling 公路混凝土梁式桥
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采煤工作面物的不安全状态界定体系构建与应用研究
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作者 秦汝祥 沈涛 +2 位作者 李世辉 操俊杰 叶峰 《安全与环境学报》 北大核心 2025年第6期2142-2152,共11页
物的不安全状态界定和消除是落实隐患排查工作的核心环节之一。为保障生产系统中物质的安全性,从种类多样的物质中提取物质共有属性进行归类,提炼基于物质属性的物质不安全特征空间。并建立依据衡量参数和评判规则的物质模式空间,实现... 物的不安全状态界定和消除是落实隐患排查工作的核心环节之一。为保障生产系统中物质的安全性,从种类多样的物质中提取物质共有属性进行归类,提炼基于物质属性的物质不安全特征空间。并建立依据衡量参数和评判规则的物质模式空间,实现对特征空间的抽象概括和定量表达,确保物质状态识别过程的客观、科学。再根据计算结果,将模式空间的抽象数据转化为包含物质状态的类型空间,进而建立四六结构模型(46Model)实现物的不安全状态界定,在此基础上提出三位一体化手段促进物的不安全状态的消除。某矿140个物质状态的验证结果表明:建立的物的不安全状态界定体系可实现物的不安全状态界定的定量化和精细化,可用率为86.43%,适用率为67.86%,准确率为78.51%;平均界定时长约为0.5 h。此外,还通过编码规律对界定与消除过程进行了标准化,研究结果对提升行业整体隐患排查治理水平具有现实意义。 展开更多
关键词 安全工程 物的不安全状态 界定体系 46Model 防护效能 采煤工作面
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基于Hybrid Model的浙江省太阳总辐射估算及其时空分布特征
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作者 顾婷婷 潘娅英 张加易 《气象科学》 2025年第2期176-181,共6页
利用浙江省两个辐射站的观测资料,对地表太阳辐射模型Hybrid Model在浙江省的适用性进行评估分析。在此基础上,利用Hybrid Model重建浙江省71个站点1971—2020年的地表太阳辐射日数据集,并分析其时空变化特征。结果表明:Hybrid Model模... 利用浙江省两个辐射站的观测资料,对地表太阳辐射模型Hybrid Model在浙江省的适用性进行评估分析。在此基础上,利用Hybrid Model重建浙江省71个站点1971—2020年的地表太阳辐射日数据集,并分析其时空变化特征。结果表明:Hybrid Model模拟效果良好,和A-P模型计算结果进行对比,杭州站的平均误差、均方根误差、平均绝对百分比误差分别为2.01 MJ·m^(-2)、2.69 MJ·m^(-2)和18.02%,而洪家站的平均误差、均方根误差、平均绝对百分比误差分别为1.41 MJ·m^(-2)、1.85 MJ·m^(-2)和11.56%,误差均低于A-P模型,且Hybrid Model在各月模拟的误差波动较小。浙江省近50 a平均地表总辐射在3733~5060 MJ·m^(-2),高值区主要位于浙北平原及滨海岛屿地区。1971—2020年浙江省太阳总辐射呈明显减少的趋势,气候倾向率为-72 MJ·m^(-2)·(10 a)^(-1),并在1980s初和2000年中期发生了突变减少。 展开更多
关键词 Hybrid Model 太阳总辐射 误差分析 时空分布
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不同分辨率和云微物理方案对四川盆地一次暴雨过程模拟的影响分析 被引量:1
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作者 马怡轩 徐国强 《大气科学》 北大核心 2025年第1期185-196,共12页
本文以美国国家环境预报中心(NCEP,National Centers for Environmental Prediction)的GFS(Global Forecast System)全球数值天气预报产品作为模式预报初始场,利用区域中尺度预报系统CMA-MESO(China Meteorological Administration Meso... 本文以美国国家环境预报中心(NCEP,National Centers for Environmental Prediction)的GFS(Global Forecast System)全球数值天气预报产品作为模式预报初始场,利用区域中尺度预报系统CMA-MESO(China Meteorological Administration Mesoscale Model)(原GRAPES_MESO)5.1版本对2021年9月3~5日发生在四川盆地的一次暴雨过程,采用3种不同分辨率(1 km、3 km、10 km)和2种云微物理参数化方案(WSM6、Thompson)设计5组试验进行数值模拟研究,结果表明:(1)试验模拟雨带与实况基本一致,但强降水时间、降水落区和降水强度与实况存在差异。随着降水阈值的提高,TS评分下降同时Bias变幅增大,空报率和漏报率也随之增加。(2)同分辨率是否采用积云参数化方案与同分辨率采用不同微物理方案对水汽通量模拟结果差异不大;5组试验在各自模拟的暴雨区均对应强烈的上升气流,且模拟强度均随分辨率提高而增大。(3)1 km分辨率下采用不同云微物理方案模拟液态粒子结果差异不大,但固态粒子明显不同。(4)3 km分辨率下加入积云参数化方案后,对于强降水中心的模拟结果存在较大偏差。整体而言,针对此次降水过程的各个试验模拟结果表明,在高分辨率条件下,Thompson方案饱和调整方案效果略好于WSM6方案,1 km_thompson方案对雨带刻画更精准,降水模拟最优。 展开更多
关键词 CMA-MESO(China Meteorological Administration Mesoscale Model) 云微物理 分辨率 暴雨
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基于24Model的动火作业事故致因文本挖掘 被引量:1
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作者 牛茂辉 李威君 +1 位作者 刘音 王璐 《中国安全科学学报》 北大核心 2025年第3期151-158,共8页
为探究工业动火作业事故的根源,提出一种基于“2-4”模型(24Model)的文本挖掘方法。首先,收集整理220篇动火作业事故报告,并作为数据集,构建基于来自变换器的双向编码器表征量(BERT)的24Model分类器,使用预训练模型训练和评估事故报告... 为探究工业动火作业事故的根源,提出一种基于“2-4”模型(24Model)的文本挖掘方法。首先,收集整理220篇动火作业事故报告,并作为数据集,构建基于来自变换器的双向编码器表征量(BERT)的24Model分类器,使用预训练模型训练和评估事故报告数据集,构建分类模型;然后,通过基于BERT的关键字提取算法(KeyBERT)和词频-逆文档频率(TF-IDF)算法的组合权重,结合24Model框架,建立动火作业事故文本关键词指标体系;最后,通过文本挖掘关键词之间的网络共现关系,分析得到事故致因之间的相互关联。结果显示,基于BERT的24Model分类器模型能够系统准确地判定动火作业事故致因类别,通过组合权重筛选得到4个层级关键词指标体系,其中安全管理体系的权重最大,结合共现网络分析得到动火作业事故的7项关键致因。 展开更多
关键词 “2-4”模型(24Model) 动火作业 事故致因 文本挖掘 指标体系
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基于MIMIC模型的生成式人工智能公众风险感知 被引量:1
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作者 陈淑 庄越 钱杨杨 《科学技术与工程》 北大核心 2025年第11期4817-4826,共10页
新一代人工智能技术的爆发式火热,将对风险社会中感知主体的风险体验产生深刻影响。运用因子分析和多指标多因素(multiple indicators and multiple causes, MIMIC)模型对生成式人工智能的12个风险场景进行研究,探究了反映公众风险感知... 新一代人工智能技术的爆发式火热,将对风险社会中感知主体的风险体验产生深刻影响。运用因子分析和多指标多因素(multiple indicators and multiple causes, MIMIC)模型对生成式人工智能的12个风险场景进行研究,探究了反映公众风险感知程度的4个指标和影响公众风险感知的5个维度。结果显示,公众对生成式人工智能的风险感知程度可以由安全、技术、使用者和企业监管期望来反映;公众的风险感知受到其对技术、宏观、权益、主体和应用风险的主观评价的影响,其中,权益风险和宏观风险的影响最为显著。结果表明,公众对生成式人工智能具有“以我为主”和“未雨绸缪”的风险感知特点。在此基础上,进一步从历史与文化视角、风险沟通视角和科技治理视角对公众的生成式人工智能风险感知进行分析,并提出了相应的对策建议。 展开更多
关键词 多指标多因素模型(MIMIC model) 生成式人工智能 公众 风险感知
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Extraction of symmetry energy coefficient in heavy-ion reactions near the Fermi energies
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作者 冷强钟 曲国峰 +8 位作者 黄宇 张鑫 段茜 陈婉君 林炜平 郑华 任培培 刘星泉 韩纪锋 《四川大学学报(自然科学版)》 北大核心 2025年第1期153-161,共9页
An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.Thi... An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.This method is applied to the primary fragments of antisymmetrized molecular dynamics(AMD)simulations for ^(46)Fe+^(46)Fe,^(40)Ca+^(40)Ca and ^(48)Ca+^(48)Ca at 35 MeV/nucleon,in order to make direct comparison to the results from the K(N,Z)method of Ono et al.In our improved method,the extracted values of a_(sym)/T increase as the size of isotopes increases whereas,in the K(N,Z)method,the results show rather constant behavior.This increase in our result is attributed to the surface contribution of the symmetry energy in finite nuclei.In order to evaluate the surface contribution,the relation a_(sym)/T=[a_(sym)^((V))(1-k_(S/V) A^(-1/3))]/T is applied and k_(S/V)=1.20~1.25 was extracted.This value is smaller than those extracted from the mass table,reflecting the weakened surface contribution at higher temperature regime.Δμ/T,the difference of the neutron-proton chemical potentials relative to the temperature,is also extracted in this method at the same time.The average values of the extractedΔμ/T,Δμ/T show a linear dependence on the proton-neutron a_(sym)metry parameter of the system,δ_(sys),andΔμ/T=(15.1±0.2)δ_(sys)-(0.5±0.1)is obtained. 展开更多
关键词 Heavy-ion reactions Symmetry energy Antisymmetrized molecular dynamics model
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Brain region-specific roles of brain-derived neurotrophic factor in social stress-induced depressive-like behavior 被引量:3
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作者 Man Han Deyang Zeng +7 位作者 Wei Tan Xingxing Chen Shuyuan Bai Qiong Wu Yushan Chen Zhen Wei Yufei Mei Yan Zeng 《Neural Regeneration Research》 SCIE CAS 2025年第1期159-173,共15页
Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice ... Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response.Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and hippocampus.Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology.In this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression.We focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine circuit.We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic system.Therefore,BDNF might be a biological indicator regulating stress-related processes in various brain regions. 展开更多
关键词 AMYGDALA chronic mild stress chronic social defeat stress corticolimbic system DEPRESSION HIPPOCAMPUS medial prefrontal cortex nucleus accumbens social stress models ventral tegmental area
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Prognostic model for esophagogastric variceal rebleeding after endoscopic treatment in liver cirrhosis: A Chinese multicenter study 被引量:2
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作者 Jun-Yi Zhan Jie Chen +7 位作者 Jin-Zhong Yu Fei-Peng Xu Fei-Fei Xing De-Xin Wang Ming-Yan Yang Feng Xing Jian Wang Yong-Ping Mu 《World Journal of Gastroenterology》 SCIE CAS 2025年第2期85-101,共17页
BACKGROUND Rebleeding after recovery from esophagogastric variceal bleeding(EGVB)is a severe complication that is associated with high rates of both incidence and mortality.Despite its clinical importance,recognized p... BACKGROUND Rebleeding after recovery from esophagogastric variceal bleeding(EGVB)is a severe complication that is associated with high rates of both incidence and mortality.Despite its clinical importance,recognized prognostic models that can effectively predict esophagogastric variceal rebleeding in patients with liver cirrhosis are lacking.AIM To construct and externally validate a reliable prognostic model for predicting the occurrence of esophagogastric variceal rebleeding.METHODS This study included 477 EGVB patients across 2 cohorts:The derivation cohort(n=322)and the validation cohort(n=155).The primary outcome was rebleeding events within 1 year.The least absolute shrinkage and selection operator was applied for predictor selection,and multivariate Cox regression analysis was used to construct the prognostic model.Internal validation was performed with bootstrap resampling.We assessed the discrimination,calibration and accuracy of the model,and performed patient risk stratification.RESULTS Six predictors,including albumin and aspartate aminotransferase concentrations,white blood cell count,and the presence of ascites,portal vein thrombosis,and bleeding signs,were selected for the rebleeding event prediction following endoscopic treatment(REPET)model.In predicting rebleeding within 1 year,the REPET model ex-hibited a concordance index of 0.775 and a Brier score of 0.143 in the derivation cohort,alongside 0.862 and 0.127 in the validation cohort.Furthermore,the REPET model revealed a significant difference in rebleeding rates(P<0.01)between low-risk patients and intermediate-to high-risk patients in both cohorts.CONCLUSION We constructed and validated a new prognostic model for variceal rebleeding with excellent predictive per-formance,which will improve the clinical management of rebleeding in EGVB patients. 展开更多
关键词 Esophagogastric variceal bleeding Variceal rebleeding Liver cirrhosis Prognostic model Risk stratification Secondary prophylaxis
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Role of iron ore in enhancing gasification of iron coke:Structural evolution,influence mechanism and kinetic analysis 被引量:1
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作者 Jie Wang Wei Wang +4 位作者 Xuheng Chen Junfang Bao Qiuyue Hao Heng Zheng Runsheng Xu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期58-69,共12页
The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the micro... The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%. 展开更多
关键词 low-carbon ironmaking iron coke GASIFICATION structural evolution kinetic model
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松嫩平原玉米秸秆遥感估算及其保护性耕作潜力分析
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作者 卓开锃 杨凤芸 杜嘉 《地理科学》 北大核心 2025年第9期2096-2106,共11页
本研究基于Google Earth Engine(GEE)平台,结合Sentinel-2时间序列遥感影像、气温、辐射数据以及文献中的收获指数,应用改进的Vegetation Photosynthesis Model(VPM)对松嫩平原的秸秆产量进行了估算。遥感影像用于提取植被生长和水分状... 本研究基于Google Earth Engine(GEE)平台,结合Sentinel-2时间序列遥感影像、气温、辐射数据以及文献中的收获指数,应用改进的Vegetation Photosynthesis Model(VPM)对松嫩平原的秸秆产量进行了估算。遥感影像用于提取植被生长和水分状况,温度与辐射数据则用于模拟模型中的生物物理过程。模型验证方面,研究通过实测数据和县级统计数据对遥感估算结果进行了验证。在此基础上,依据保护性耕作的定义和实施条件,结合估算的秸秆产量和气候数据,分析了松嫩平原的保护性耕作潜力。研究结果表明,2022年秸秆估算产量与县级统计数据的相关系数R^(2)为0.93,均方根误差(RMSE)为17.52万t;实测与估算的秸秆产量相关系数R^(2)为0.62,RMSE为936.4 kg/hm^(2),改进的VPM模型在秸秆产量估算中的准确性较好。基于气候和秸秆产量条件,松嫩平原有94.93%的区域适宜进行保护性耕作。研究证实了VPM模型在玉米(Zea mays)秸秆产量估算中的有效性,并对松嫩平原的保护性耕作潜力进行了评估。研究可为秸秆资源的综合利用与区域保护性耕作的实施提供科学数据支持,为农业可持续发展提供理论依据。 展开更多
关键词 Vegetation Photosynthesis Model(VPM) Sentinel-2 秸秆产量 保护性耕作潜力
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Landslide Susceptibility Mapping Using RBFN-Based Ensemble Machine Learning Models 被引量:1
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作者 Duc-Dam Nguyen Nguyen Viet Tiep +5 位作者 Quynh-Anh Thi Bui Hiep Van Le Indra Prakash Romulus Costache Manish Pandey Binh Thai Pham 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期467-500,共34页
This study was aimed to prepare landslide susceptibility maps for the Pithoragarh district in Uttarakhand,India,using advanced ensemble models that combined Radial Basis Function Networks(RBFN)with three ensemble lear... This study was aimed to prepare landslide susceptibility maps for the Pithoragarh district in Uttarakhand,India,using advanced ensemble models that combined Radial Basis Function Networks(RBFN)with three ensemble learning techniques:DAGGING(DG),MULTIBOOST(MB),and ADABOOST(AB).This combination resulted in three distinct ensemble models:DG-RBFN,MB-RBFN,and AB-RBFN.Additionally,a traditional weighted method,Information Value(IV),and a benchmark machine learning(ML)model,Multilayer Perceptron Neural Network(MLP),were employed for comparison and validation.The models were developed using ten landslide conditioning factors,which included slope,aspect,elevation,curvature,land cover,geomorphology,overburden depth,lithology,distance to rivers and distance to roads.These factors were instrumental in predicting the output variable,which was the probability of landslide occurrence.Statistical analysis of the models’performance indicated that the DG-RBFN model,with an Area Under ROC Curve(AUC)of 0.931,outperformed the other models.The AB-RBFN model achieved an AUC of 0.929,the MB-RBFN model had an AUC of 0.913,and the MLP model recorded an AUC of 0.926.These results suggest that the advanced ensemble ML model DG-RBFN was more accurate than traditional statistical model,single MLP model,and other ensemble models in preparing trustworthy landslide susceptibility maps,thereby enhancing land use planning and decision-making. 展开更多
关键词 Landslide susceptibility map spatial analysis ensemble modelling information values(IV)
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A Novel Self-Supervised Learning Network for Binocular Disparity Estimation 被引量:1
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作者 Jiawei Tian Yu Zhou +5 位作者 Xiaobing Chen Salman A.AlQahtani Hongrong Chen Bo Yang Siyu Lu Wenfeng Zheng 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期209-229,共21页
Two-dimensional endoscopic images are susceptible to interferences such as specular reflections and monotonous texture illumination,hindering accurate three-dimensional lesion reconstruction by surgical robots.This st... Two-dimensional endoscopic images are susceptible to interferences such as specular reflections and monotonous texture illumination,hindering accurate three-dimensional lesion reconstruction by surgical robots.This study proposes a novel end-to-end disparity estimation model to address these challenges.Our approach combines a Pseudo-Siamese neural network architecture with pyramid dilated convolutions,integrating multi-scale image information to enhance robustness against lighting interferences.This study introduces a Pseudo-Siamese structure-based disparity regression model that simplifies left-right image comparison,improving accuracy and efficiency.The model was evaluated using a dataset of stereo endoscopic videos captured by the Da Vinci surgical robot,comprising simulated silicone heart sequences and real heart video data.Experimental results demonstrate significant improvement in the network’s resistance to lighting interference without substantially increasing parameters.Moreover,the model exhibited faster convergence during training,contributing to overall performance enhancement.This study advances endoscopic image processing accuracy and has potential implications for surgical robot applications in complex environments. 展开更多
关键词 Parallax estimation parallax regression model self-supervised learning Pseudo-Siamese neural network pyramid dilated convolution binocular disparity estimation
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基于大语言模型的生产安全(工矿商贸)事故报告数字化方法 被引量:2
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作者 张凯 周清 +2 位作者 商景林 李焱 程嘉昇 《中国安全生产科学技术》 北大核心 2025年第1期38-47,共10页
为推动生产安全管理数字化转型、智能化提取事故报告价值数据,基于大语言模型并结合信息抽取与文本分类技术,提出1种面向工矿商贸行业领域的生产安全事故报告数字化方法。首先分析事故报告结构特点和编写规律,以正则化方法匹配提取事故... 为推动生产安全管理数字化转型、智能化提取事故报告价值数据,基于大语言模型并结合信息抽取与文本分类技术,提出1种面向工矿商贸行业领域的生产安全事故报告数字化方法。首先分析事故报告结构特点和编写规律,以正则化方法匹配提取事故报告关键段落,实现文本预处理,然后建立命名实体识别任务对事故报告基本特征进行文本抽取,并验证大语言模型微调前后的信息抽取效果,同时根据24Model设计事故原因模块化分类指标,通过模型参数微调实现事故致因特征层级分类预测,并作多场景和单一场景下致因分类对比实验。研究结果表明:大语言模型具备较强的泛化能力,通过少量数据标注与参数微调可快速适配事故报告信息抽取、致因分类任务,模型综合评价指标分别可达0.87和0.85,本文所构建的数字化方法可行有效。研究结果可为应急管理大数据底座的建设提供技术参考。 展开更多
关键词 事故报告 数字化 大语言模型 24Model 信息抽取 致因分类
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胫骨内侧应力在跑步运动过程中的计算机仿真分析
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作者 孙媛 杨晨 马运超 《中国组织工程研究》 CAS 北大核心 2025年第27期5802-5809,共8页
背景:内侧胫骨应力综合征是困扰跑步者的一种常见的下肢慢性损伤,其损伤机制可能与“肌肉牵引”假说有关,然而这种假说还没有得到完全的证实。目的:使用肌骨仿真系统和有限元分析等方法,考察比目鱼肌、胫骨后肌、趾长屈肌在跑步过程中... 背景:内侧胫骨应力综合征是困扰跑步者的一种常见的下肢慢性损伤,其损伤机制可能与“肌肉牵引”假说有关,然而这种假说还没有得到完全的证实。目的:使用肌骨仿真系统和有限元分析等方法,考察比目鱼肌、胫骨后肌、趾长屈肌在跑步过程中的收缩特征是否与跑步时胫骨内侧缘的应力水平存在相关性,从而影响内侧胫骨应力综合征的发生与发展。方法:将6名受试者不同速度跑步时的动作捕捉数据输入Anybody Modeling System骨肌仿真系统,对2.5,3.5,4.5 m/s三种跑步速度情况下的步态支撑期进行逆动力学仿真,将仿真得到的边界条件与有限元模型结合,考察胫骨内侧的应力分布情况。使用偏最小二乘回归方法分析自变量(肌力、弹性势能)与因变量(胫骨应力)之间的相关性。结果与结论:①胫骨应力水平在支撑期(1%-50%)存在速度间的统计学差异(P=0.044,F=3.834,η_(p)^(2)=0.040);②3种速度下,比目鱼肌的肌力与胫骨应力之间的平均相关性最高(r=12.999),其次胫骨后肌肌力与胫骨应力的平均相关性排名第二(r=-10.735),然后依次是趾长屈肌肌力(r=-9.751),胫骨后肌弹性势能(r=8.012),比目鱼肌弹性势能(r=9.076),趾长屈肌弹性势能(r=-4.782);③结果表明,跑步速度的增加,胫骨应力水平随之上升;比目鱼肌的收缩及吸收的弹性势能在跑步过程中的释放对于内侧胫骨应力综合征的发展将产生不可忽略的影响,而胫骨后肌和趾长屈肌的作用被高估了;综合来看,研究支持了“肌肉牵引”假说中比目鱼肌的收缩对内侧胫骨应力综合征发展发挥作用的推论。 展开更多
关键词 胫骨应力综合征 生物力学仿真 内侧胫骨应力综合征 anybody modeling system ABAQUS 有限元分析
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Reduced mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor contributes to neurodegeneration in a model of spinal and bulbar muscular atrophy pathology 被引量:1
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作者 Yiyang Qin Wenzhen Zhu +6 位作者 Tingting Guo Yiran Zhang Tingting Xing Peng Yin Shihua Li Xiao-Jiang Li Su Yang 《Neural Regeneration Research》 SCIE CAS 2025年第9期2655-2666,共12页
Spinal and bulbar muscular atrophy is a neurodegenerative disease caused by extended CAG trinucleotide repeats in the androgen receptor gene,which encodes a ligand-dependent transcription facto r.The mutant androgen r... Spinal and bulbar muscular atrophy is a neurodegenerative disease caused by extended CAG trinucleotide repeats in the androgen receptor gene,which encodes a ligand-dependent transcription facto r.The mutant androgen receptor protein,characterized by polyglutamine expansion,is prone to misfolding and forms aggregates in both the nucleus and cytoplasm in the brain in spinal and bulbar muscular atrophy patients.These aggregates alter protein-protein interactions and compromise transcriptional activity.In this study,we reported that in both cultured N2a cells and mouse brain,mutant androgen receptor with polyglutamine expansion causes reduced expression of mesencephalic astrocyte-de rived neurotrophic factor.Overexpressio n of mesencephalic astrocyte-derived neurotrophic factor amelio rated the neurotoxicity of mutant androgen receptor through the inhibition of mutant androgen receptor aggregation.Conversely.knocking down endogenous mesencephalic astrocyte-derived neurotrophic factor in the mouse brain exacerbated neuronal damage and mutant androgen receptor aggregation.Our findings suggest that inhibition of mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor is a potential mechanism underlying neurodegeneration in spinal and bulbar muscular atrophy. 展开更多
关键词 androgen receptor mesencephalic astrocyte-derived neurotrophic factor mouse model NEURODEGENERATION neuronal loss neurotrophic factor polyglutamine disease protein misfolding spinal and bulbar muscular atrophy transcription factor
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Circadian rhythms and their roles in the pathogenesis and treatment of depression 被引量:1
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作者 SMITH William Kojo ZHONG Zhao-Min +3 位作者 WANG Willow Tsanzi HASSAN Najm Ul KHAN Moheb WANG Han 《生理学报》 北大核心 2025年第4期689-711,共23页
Major depressive disorder(MDD)affects people all over the world,and yet,its etiology is complex and remains incompletely understood.In this review,we aim to assess recent advances in understanding depression and its r... Major depressive disorder(MDD)affects people all over the world,and yet,its etiology is complex and remains incompletely understood.In this review,we aim to assess recent advances in understanding depression and its regulation,as well as its interaction with circadian rhythms.Circadian rhythms are internalized representations of the periodic daily light and dark cycles.Accumulating evidence has shown that MDD and the related mental disorders are associated with disrupted circadian rhythms.In particular,depression has often been linked to abnormalities in circadian rhythms because dysregulation of the circadian system increases susceptibility to MDD.The fact that several rhythms are disrupted in depressed patients suggests that these disruptions are not restricted to any one rhythm but rather involve the molecular circadian clock core machinery.The sleep-wake cycle is one rhythm that is often disrupted in depression,which often leads to disturbances in other rhythms.The circadian disruptions manifested in depressed patients and the effectiveness and fast action of chronobiologically based treatments highlight the circadian system as a key therapeutic target in the treatment of depression.This review assesses the evidence on rising depression rates and examines their contributing factors,including circadian misalignment.We discuss key hypotheses underlying depression pathogenesis,potential etiology,and relevant animal models,and underscore potential mechanisms driving depression's growing burden and how understanding these factors is critical for improving prevention and treatment strategies. 展开更多
关键词 circadian rhythms sleep-wake cycle DEPRESSION THERAPEUTICS animal models
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Robustness Optimization Algorithm with Multi-Granularity Integration for Scale-Free Networks Against Malicious Attacks 被引量:1
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作者 ZHANG Yiheng LI Jinhai 《昆明理工大学学报(自然科学版)》 北大核心 2025年第1期54-71,共18页
Complex network models are frequently employed for simulating and studyingdiverse real-world complex systems.Among these models,scale-free networks typically exhibit greater fragility to malicious attacks.Consequently... Complex network models are frequently employed for simulating and studyingdiverse real-world complex systems.Among these models,scale-free networks typically exhibit greater fragility to malicious attacks.Consequently,enhancing the robustness of scale-free networks has become a pressing issue.To address this problem,this paper proposes a Multi-Granularity Integration Algorithm(MGIA),which aims to improve the robustness of scale-free networks while keeping the initial degree of each node unchanged,ensuring network connectivity and avoiding the generation of multiple edges.The algorithm generates a multi-granularity structure from the initial network to be optimized,then uses different optimization strategies to optimize the networks at various granular layers in this structure,and finally realizes the information exchange between different granular layers,thereby further enhancing the optimization effect.We propose new network refresh,crossover,and mutation operators to ensure that the optimized network satisfies the given constraints.Meanwhile,we propose new network similarity and network dissimilarity evaluation metrics to improve the effectiveness of the optimization operators in the algorithm.In the experiments,the MGIA enhances the robustness of the scale-free network by 67.6%.This improvement is approximately 17.2%higher than the optimization effects achieved by eight currently existing complex network robustness optimization algorithms. 展开更多
关键词 complex network model MULTI-GRANULARITY scale-free networks ROBUSTNESS algorithm integration
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基于UVM的PCIe交换芯片Switch子系统验证平台的设计
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作者 郑锐 沈剑良 +2 位作者 刘冬培 李智超 曹睿 《计算机应用研究》 北大核心 2025年第5期1480-1489,共10页
PCIe是一种高速串行计算机扩展总线标准,据此设计的PCIe交换芯片可将CPU提供的PCIe通道扩展出更多的PCIe接口。然而,随着PCIe交换芯片设计复杂度和验证向量剧增,传统基于Verilog搭建的验证平台难以实现对逻辑复杂的Switch子系统高效地验... PCIe是一种高速串行计算机扩展总线标准,据此设计的PCIe交换芯片可将CPU提供的PCIe通道扩展出更多的PCIe接口。然而,随着PCIe交换芯片设计复杂度和验证向量剧增,传统基于Verilog搭建的验证平台难以实现对逻辑复杂的Switch子系统高效地验证,且缺乏功能覆盖率模型。为解决上述问题,采用UVM通用验证方法学,搭建了针对PCIe交换芯片中Switch子系统的验证平台,采用层次划分设计,支持覆盖率驱动,且较于一般UVM验证平台作出效率优化。具体而言,首先,对平台组件Reference Model建立通信对象和通信方式进行优化设计;其次,对平台组件ScoreBoard的比对方式和接收报文端口进行改进;最后,依据PCIe协议及交换芯片特点,对功能点进行梳理分类后针对性地设计了测试用例,对Switch子系统进行全面验证。经信号波形及覆盖率数据的分析表明,改进后的验证平台在没有人为过滤的情况下实现了96.8%的代码覆盖率和100%的功能覆盖率,仿真时间平均减少了约10%。该平台显著提升了验证效率,高效地支撑了PCIe交换芯片的验证工作,为相关UVM验证平台的搭建提供了参考。 展开更多
关键词 PCIe交换芯片 Switch子系统 UVM验证平台 reference model ScoreBoard 覆盖率
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YOLOv8改进算法在油茶果分拣中的应用
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作者 刘姜毅 高自成 +2 位作者 刘怀粤 尹浇钦 罗媛尹 《林业工程学报》 北大核心 2025年第1期120-127,共8页
现有的油茶果分拣系统所依赖的YOLO等算法的目标检测、实例分割在低尺寸及密集型样本中鲁棒性较差,存在机械臂常抓取到枝叶、抓取不牢固、易脱落等问题。大部分系统使用目标识别,无法准确识别油茶果具体轮廓信息,不能对油茶果进行大小... 现有的油茶果分拣系统所依赖的YOLO等算法的目标检测、实例分割在低尺寸及密集型样本中鲁棒性较差,存在机械臂常抓取到枝叶、抓取不牢固、易脱落等问题。大部分系统使用目标识别,无法准确识别油茶果具体轮廓信息,不能对油茶果进行大小分类。针对这一问题,研究提出了YOWNet模型应对油茶果分拣的小目标、高密度识别任务。首先,研究了自动化边缘标注脚本,脚本调用零样本Segment Anything框架对原有已标注的油茶果目标检测框提取兴趣区间,将其自动转化为边缘标注信息;其次,为了提高模型对小目标的识别能力,研究摒弃了现有的固定感受野的卷积模块,针对油茶果特性提出三维注意力动态卷积模块用于捕捉特征图中的关键信息;最后,研究通过使用Wise⁃IoU损失函数,基于动态非单调聚焦机制的边界框损失,提升边框回归精度。总体网络模型命名为YOWNet,通过与YOLOv8在油茶果上的消融实验对比,试验结果表明:YOWNet模型能够快速准确地识别油茶果实例,在私有数据集上,准确度、Box_loss可达89.90%和0.523。 展开更多
关键词 油茶果 三维动态卷积 实例分割 YOLOv8 Segment Anything Model Wise⁃IoU
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