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Mechanism of post cardiac arrest syndrome based on animal models of cardiac arrest
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作者 Halidan ABUDU WANG Yiping +10 位作者 HE Kang LIU Ziquan GUO Liqiong DONG Jinrui Ailijiang KADEER XU Guowu LIU Yanqing MENG Xiangyan CAI Jinxia LI Yongmao FAN Haojun 《中南大学学报(医学版)》 北大核心 2025年第5期731-746,共16页
Cardiac arrest(CA)is a critical condition in the field of cardiovascular medicine.Despite successful resuscitation,patients continue to have a high mortality rate,largely due to post CA syndrome(PCAS).However,the inju... Cardiac arrest(CA)is a critical condition in the field of cardiovascular medicine.Despite successful resuscitation,patients continue to have a high mortality rate,largely due to post CA syndrome(PCAS).However,the injury and pathophysiological mechanisms underlying PCAS remain unclear.Experimental animal models are valuable tools for exploring the etiology,pathogenesis,and potential interventions for CA and PCAS.Current CA animal models include electrical induction of ventricular fibrillation(VF),myocardial infarction,high potassium,asphyxia,and hemorrhagic shock.Although these models do not fully replicate the complexity of clinical CA,the mechanistic insights they provide remain highly relevant,including post-CA brain injury(PCABI),post-CA myocardial dysfunction(PAMD),systemic ischaemia/reperfusion injury(IRI),and the persistent precipitating pathology.Summarizing the methods of establishing CA models,the challenges encountered in the modeling process,and the mechanisms of PCAS can provide a foundation for developing standardized CA modeling protocols. 展开更多
关键词 cardiac arrest animal model post cardiac arrest syndrome PATHOPHYSIOLOGY modeling method
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Comparative analysis of machine learning and statistical models for cotton yield prediction in major growing districts of Karnataka,India
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作者 THIMMEGOWDA M.N. MANJUNATHA M.H. +4 位作者 LINGARAJ H. SOUMYA D.V. JAYARAMAIAH R. SATHISHA G.S. NAGESHA L. 《Journal of Cotton Research》 2025年第1期40-60,共21页
Background Cotton is one of the most important commercial crops after food crops,especially in countries like India,where it’s grown extensively under rainfed conditions.Because of its usage in multiple industries,su... Background Cotton is one of the most important commercial crops after food crops,especially in countries like India,where it’s grown extensively under rainfed conditions.Because of its usage in multiple industries,such as textile,medicine,and automobile industries,it has greater commercial importance.The crop’s performance is greatly influenced by prevailing weather dynamics.As climate changes,assessing how weather changes affect crop performance is essential.Among various techniques that are available,crop models are the most effective and widely used tools for predicting yields.Results This study compares statistical and machine learning models to assess their ability to predict cotton yield across major producing districts of Karnataka,India,utilizing a long-term dataset spanning from 1990 to 2023 that includes yield and weather factors.The artificial neural networks(ANNs)performed superiorly with acceptable yield deviations ranging within±10%during both vegetative stage(F1)and mid stage(F2)for cotton.The model evaluation metrics such as root mean square error(RMSE),normalized root mean square error(nRMSE),and modelling efficiency(EF)were also within the acceptance limits in most districts.Furthermore,the tested ANN model was used to assess the importance of the dominant weather factors influencing crop yield in each district.Specifically,the use of morning relative humidity as an individual parameter and its interaction with maximum and minimum tempera-ture had a major influence on cotton yield in most of the yield predicted districts.These differences highlighted the differential interactions of weather factors in each district for cotton yield formation,highlighting individual response of each weather factor under different soils and management conditions over the major cotton growing districts of Karnataka.Conclusions Compared with statistical models,machine learning models such as ANNs proved higher efficiency in forecasting the cotton yield due to their ability to consider the interactive effects of weather factors on yield forma-tion at different growth stages.This highlights the best suitability of ANNs for yield forecasting in rainfed conditions and for the study on relative impacts of weather factors on yield.Thus,the study aims to provide valuable insights to support stakeholders in planning effective crop management strategies and formulating relevant policies. 展开更多
关键词 COTTON Machine learning models Statistical models Yield forecast Artificial neural network Weather variables
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A comprehensive comparison of hydro-elastoplastic-damage and capelastoplastic-damage material models for concrete subjected to impact and blast loadings
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作者 Shufeng Shi Xiangzhen Kong +2 位作者 Junyu Fan Yong Peng Qin Fang 《Defence Technology(防务技术)》 2025年第5期83-104,共22页
Concrete material model plays an important role in numerical predictions of its dynamic responses subjected to projectile impact and charge explosion.Current concrete material models could be distinguished into two ki... Concrete material model plays an important role in numerical predictions of its dynamic responses subjected to projectile impact and charge explosion.Current concrete material models could be distinguished into two kinds,i.e.,the hydro-elastoplastic-damage model with independent equation of state and the cap-elastoplastic-damage model with continuous cap surface.The essential differences between the two kind models are vital for researchers to choose an appropriate kind of concrete material model for their concerned problems,while existing studies have contradictory conclusions.To resolve this issue,the constitutive theories of the two kinds of models are firstly overviewed.Then,the constitutive theories between the two kinds of models are comprehensively compared and the main similarities and differences are clarified,which are demonstrated by single element numerical examples.Finally,numerical predictions for projectile penetration and charge explosion experiments on concrete targets are compared to further demonstrate the conclusion made by constitutive comparison.It is found that both the two kind models could be used to simulate the dynamic responses of concrete under projectile impact and blast loadings,if the parameter needed in material models are well calibrated,although some discrepancies between them may exist. 展开更多
关键词 Concrete material model Hydro-elastoplastic-damage material model Cap-elastoplastic-damage model Projectile impact Charge explosion
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Intelligent modeling method for OV models in DoDAF2.0 based on knowledge graph
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作者 ZHANG Yue JIANG Jiang +3 位作者 YANG Kewei WANG Xingliang XU Chi LI Minghao 《Journal of Systems Engineering and Electronics》 2025年第1期139-154,共16页
Architecture framework has become an effective method recently to describe the system of systems(SoS)architecture,such as the United States(US)Department of Defense Architecture Framework Version 2.0(DoDAF2.0).As a vi... Architecture framework has become an effective method recently to describe the system of systems(SoS)architecture,such as the United States(US)Department of Defense Architecture Framework Version 2.0(DoDAF2.0).As a viewpoint in DoDAF2.0,the operational viewpoint(OV)describes operational activities,nodes,and resource flows.The OV models are important for SoS architecture development.However,as the SoS complexity increases,constructing OV models with traditional methods exposes shortcomings,such as inefficient data collection and low modeling standards.Therefore,we propose an intelligent modeling method for five OV models,including operational resource flow OV-2,organizational relationships OV-4,operational activity hierarchy OV-5a,operational activities model OV-5b,and operational activity sequences OV-6c.The main idea of the method is to extract OV architecture data from text and generate interoperable OV models.First,we construct the OV meta model based on the DoDAF2.0 meta model(DM2).Second,OV architecture named entities is recognized from text based on the bidirectional long short-term memory and conditional random field(BiLSTM-CRF)model.And OV architecture relationships are collected with relationship extraction rules.Finally,we define the generation rules for OV models and develop an OV modeling tool.We use unmanned surface vehicles(USV)swarm target defense SoS architecture as a case to verify the feasibility and effectiveness of the intelligent modeling method. 展开更多
关键词 system of systems(SoS)architecture operational viewpoint(OV)model meta model bidirectional long short-term memory and conditional random field(BiLSTM-CRF) model generation systems modeling language
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Novel damage constitutive models and new quantitative identification method for stress thresholds of rocks under uniaxial compression
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作者 DU Kun YI Yang +3 位作者 LUO Xin-yao LIU Kai LI Peng WANG Shao-feng 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2658-2675,共18页
Four key stress thresholds exist in the compression process of rocks,i.e.,crack closure stress(σ_(cc)),crack initiation stress(σ_(ci)),crack damage stress(σ_(cd))and compressive strength(σ_(c)).The quantitative id... Four key stress thresholds exist in the compression process of rocks,i.e.,crack closure stress(σ_(cc)),crack initiation stress(σ_(ci)),crack damage stress(σ_(cd))and compressive strength(σ_(c)).The quantitative identifications of the first three stress thresholds are of great significance for characterizing the microcrack growth and damage evolution of rocks under compression.In this paper,a new method based on damage constitutive model is proposed to quantitatively measure the stress thresholds of rocks.Firstly,two different damage constitutive models were constructed based on acoustic emission(AE)counts and Weibull distribution function considering the compaction stages of the rock and the bearing capacity of the damage element.Then,the accumulative AE counts method(ACLM),AE count rate method(CRM)and constitutive model method(CMM)were introduced to determine the stress thresholds of rocks.Finally,the stress thresholds of 9 different rocks were identified by ACLM,CRM,and CMM.The results show that the theoretical stress−strain curves obtained from the two damage constitutive models are in good agreement with that of the experimental data,and the differences between the two damage constitutive models mainly come from the evolutionary differences of the damage variables.The results of the stress thresholds identified by the CMM are in good agreement with those identified by the AE methods,i.e.,ACLM and CRM.Therefore,the proposed CMM can be used to determine the stress thresholds of rocks. 展开更多
关键词 stress threshold acoustic emission damage constitutive model damage element quantitative method
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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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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MODELS的工频弧光接地过电压的仿真 被引量:11
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作者 金恩淑 杨明芳 +1 位作者 李卫刚 陈韬 《电力系统保护与控制》 EI CSCD 北大核心 2009年第13期24-28,共5页
弧光接地过电压是中性点不接地系统中危害最大的过电压之一。目前,关于弧光接地过电压的研究大都采用系统仿真,基于工频熄弧理论,通过控制开关的闭合来模拟电弧的熄灭和重燃,观察弧光接地过电压情况。由于电弧的熄灭和重燃具有强烈的统... 弧光接地过电压是中性点不接地系统中危害最大的过电压之一。目前,关于弧光接地过电压的研究大都采用系统仿真,基于工频熄弧理论,通过控制开关的闭合来模拟电弧的熄灭和重燃,观察弧光接地过电压情况。由于电弧的熄灭和重燃具有强烈的统计特性,电弧不一定是在工频过零时熄灭,也不一定是在电压达到最大值时重燃。因此,按一个工频周期来设定开关的开闭时间模拟弧光接地过电压时,模型不够准确。鉴于这种情况,在对弧光接地过电压产生机理深入研究的基础上,提出了一种新的开关控制方法,采用EMTP中的控制系统暂态分析TACS模块和MODELS模块对开关的控制部分进行处理。运用MODELS模块中特定的MODELS语言编写控制程序,输出一个信号作为TACS开关的输入控制信号,当满足给定电压和电流门槛值时,开关便会相应地闭合及断开。不必按一个工频周期来设定开关的开闭时间,提高了仿真模型的精确性。将其应用于10kV中性点不接地系统及小电阻接地系统的弧光接地过电压的研究,取得了预期效果,具有很好的应用前景。 展开更多
关键词 弧光接地过电压 中性点不接地 小电阻接地 TACS models
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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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Models3在北京地区PM_(10)模拟应用中的三维系统检验 被引量:3
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作者 赵秀勇 程水源 +2 位作者 杨素英 陈东升 邰恒 《环境科学与技术》 CAS CSCD 北大核心 2009年第10期113-117,140,共6页
为研究北京地区大气PM10的变化规律和三维空间结构,文章基于Models3/CMAQ空气质量模式,利用北京及周边省市详细调查的污染源数据,采取双层网格嵌套技术建立起适用于北京及周边地区的大气PM10数值模拟系统。为了检验该模式系统的准确性... 为研究北京地区大气PM10的变化规律和三维空间结构,文章基于Models3/CMAQ空气质量模式,利用北京及周边省市详细调查的污染源数据,采取双层网格嵌套技术建立起适用于北京及周边地区的大气PM10数值模拟系统。为了检验该模式系统的准确性和可靠性,文章将模拟结果与北京市城近郊区7个地面站近2500h的逐时地面监测数据以及一次典型污染过程的激光雷达垂直观测记录分别进行了对比分析,结果表明,该模式系统较好的反映了北京地区PM10浓度三维时空分布特征,是研究华北地区复杂地形下大气PM10传输及演变规律的一个有效工具。 展开更多
关键词 models3 MM5 激光雷达 模式检验
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Solubility and Thermodynamic Modeling of 3⁃Nitro⁃1,2,4⁃triazole⁃5⁃one(NTO)in Different Binary Solvents 被引量:1
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作者 GUO Hao-qi YANG Yu-lin 《含能材料》 北大核心 2025年第3期295-303,共9页
Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging f... Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ). 展开更多
关键词 3-nitro-l 2 4-triazole-5-one(NTO) SOLUBILITY thermodynamic models apparent thermodynamic analysis
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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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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:1
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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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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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如何吸引我:个性化推荐促进用户习惯形成的作用机制 被引量:1
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作者 赵立 付兵 《财经论丛》 北大核心 2025年第2期88-100,共13页
利用数字技术预测用户兴趣和偏好而“投其所好”的个性化推荐已成为电商平台普遍使用的数字化营销工具,但基于个性化信息的精准推荐所形成的“过滤气泡”现象会使用户产生抗拒心理,并降低其对电商平台的使用频率。至于个性化推荐如何有... 利用数字技术预测用户兴趣和偏好而“投其所好”的个性化推荐已成为电商平台普遍使用的数字化营销工具,但基于个性化信息的精准推荐所形成的“过滤气泡”现象会使用户产生抗拒心理,并降低其对电商平台的使用频率。至于个性化推荐如何有效吸引用户形成习惯性使用的作用机制,目前尚不明确。本研究结合自我决定理论和Hook Model框架,从自我决定视角探究个性化推荐在塑造用户电商平台使用习惯中的作用机制。情景实验研究发现:推荐多样性和推荐新颖性对自主感具有显著正向影响,推荐新颖性对归属感具有显著正向影响;自主感在推荐多样性及推荐新颖性与用户习惯之间均存在中介效应,归属感在推荐新颖性与用户习惯之间存在中介效应。进一步分析发现:推荐新颖性对用户归属感的影响在搜寻品与体验品之间差异显著,推荐新颖性通过归属感影响用户习惯的中介作用在搜寻品与体验品、信任品之间均具有显著差异。本研究拓展了个性化推荐领域的研究视角,对电商平台提升个性化推荐服务水平具有启示意义。 展开更多
关键词 Hook Model 自我决定理论 推荐多样性 推荐新颖性 用户习惯
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基于24Model的动火作业事故致因文本挖掘
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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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Comparative study on the oblique water-entry of high-speed projectile based on rigid-body and elastic-plastic body model 被引量:1
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作者 Xiangyan Liu Xiaowei Cai +3 位作者 Zhengui Huang Yu Hou Jian Qin Zhihua Chen 《Defence Technology(防务技术)》 2025年第4期133-155,共23页
To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc... To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°. 展开更多
关键词 Fluid-structure interaction Rigid-body model Elastic-plastic model Structural deformation Impact loads Structural safety of projectile
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Penetration-deflagration coupling damage performance of rod-like reactive shaped charge penetrator impacting thick steel plates 被引量:1
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作者 Tao Sun Haifu Wang +3 位作者 Shipeng Wang Jie Gong Wenhao Qiu Yuanfeng Zheng 《Defence Technology(防务技术)》 2025年第7期152-164,共13页
The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagra... The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly. 展开更多
关键词 Reactive materials Al-PTFE composites Penetration model Damage effect
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Study on cook-off characteristics and thermal safety venting area of RBOE charge 被引量:1
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作者 Kebin Zhang Wenbin Li +3 位作者 Changfang Zhao Zhifang Wei Shuxia Zhang Jin Li 《Defence Technology(防务技术)》 2025年第1期271-287,共17页
RBOE is a new type of DNAN-based high-energy melt-cast mixed explosive,whose safety under thermal stimulation is significantly affected by heating conditions and venting area of the warhead.Based on the thermal decomp... RBOE is a new type of DNAN-based high-energy melt-cast mixed explosive,whose safety under thermal stimulation is significantly affected by heating conditions and venting area of the warhead.Based on the thermal decomposition reaction characteristics and combustion characteristics of each component of RBOE explosive,the cook-off calculation models of RBOE warhead before and after ignition were established.In addition,closed and vented warheads were designed,as well as fast and slow cook-off test devices.The cook-off characteristics and thermal safety venting area of RBOE warhead were extensively studied.The results showed that the closed RBOE warhead underwent deflagration reaction under both slow and fast cook-off conditions.The calculation result of the shell wall temperature before slow cookoff ignition response of the warhead was 454.06 K,with an error of+1.75%compared to the test result of462.15 K,and the temperature rise rate calculated was in good agreement with the test.The calculated ignition time of RBOE warhead under fast cook-off was 161 s,with an error of+8.8%compared to the test result of 148 s,which verified the accuracy of cook-off model of RBOE warhead before ignition.According to the cook-off calculation model of the warhead after ignition and cook-off test of the vented warhead,it was determined that the thermal safety venting area was 1124.61 mm^(2)for fast cook-off and 530.66 mm~2 for slow cook-off,effectively preventing the reaction of warhead above combustion.Therefore,this study provides a scientific basis for the thermal safety design and evaluation of insensitive warheads. 展开更多
关键词 RBOE explosive Cook-off model Temperature distribution Pressure growth Venting area
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