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Solution of Self-similar Equations of the k-ε Model in the Shear Turbulent Mixing Problem and Its Numerical Simulation
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作者 Vyacheslav P. Statsenko Yulia V. Tret'yachenko Yury V. Yanilkin 《Journal of Physical Science and Application》 2015年第6期377-395,共19页
The paper presents the k-ε model equations of turbulence with a single set of constants chosen by the authors, which is appropriate to simulate a wide range of turbulent flows. The model validation has been performed... The paper presents the k-ε model equations of turbulence with a single set of constants chosen by the authors, which is appropriate to simulate a wide range of turbulent flows. The model validation has been performed for a number of flows and its main results are given in the paper. The turbulent mixing of flow with shear in the tangential velocity component is discussed in details. An analytical solution to the system of ordinary differential equations of the k-ε model of turbulent mixing has been found for the self-similar regime of flow. The model coefficients were chosen using simulation results for some simplest turbulent flows. The solution can be used for the verification of codes. The numerical simulation of the problem has been performed by the 2D code EGAK using this model. A good agreement of the numerical simulation results with the self-similar solution, 3D DNS results and known experimental data has been achieved. This allows stating that the k-ε model constants chosen by the authors are acceptable for the considered flow. 展开更多
关键词 The k-ε model of turbulent mixing shear turbulent mixing self-similar equations numerical simulation.
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Task-Oriented Semantic Communication with Foundation Models
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作者 Chen Mingkai Liu Minghao +2 位作者 Zhang Zhe Xu Zhiping Wang Lei 《China Communications》 SCIE CSCD 2024年第7期65-77,共13页
In the future development direction of the sixth generation(6G)mobile communication,several communication models are proposed to face the growing challenges of the task.The rapid development of artificial intelligence... In the future development direction of the sixth generation(6G)mobile communication,several communication models are proposed to face the growing challenges of the task.The rapid development of artificial intelligence(AI)foundation models provides significant support for efficient and intelligent communication interactions.In this paper,we propose an innovative semantic communication paradigm called task-oriented semantic communication system with foundation models.First,we segment the image by using task prompts based on the segment anything model(SAM)and contrastive language-image pretraining(CLIP).Meanwhile,we adopt Bezier curve to enhance the mask to improve the segmentation accuracy.Second,we have differentiated semantic compression and transmission approaches for segmented content.Third,we fuse different semantic information based on the conditional diffusion model to generate high-quality images that satisfy the users'specific task requirements.Finally,the experimental results show that the proposed system compresses the semantic information effectively and improves the robustness of semantic communication. 展开更多
关键词 diffusion model foundation model joint source-channel coding task-oriented semantic communication
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Construction and validation of a risk-prediction model for anastomotic leakage after radical gastrectomy: A cohort study in China
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作者 Jinrui Wang Xiaolin Liu +6 位作者 Hongying Pan Yihong Xu Mizhi Wu Xiuping Li Yang Gao Meijuan Wang Mengya Yan 《Laparoscopic, Endoscopic and Robotic Surgery》 2024年第1期34-43,共10页
Objectives:Anastomotic leakage(AL)stands out as a prevalent and severe complication following gastric cancer surgery.It frequently precipitates additional serious complications,significantly influencing the overall su... Objectives:Anastomotic leakage(AL)stands out as a prevalent and severe complication following gastric cancer surgery.It frequently precipitates additional serious complications,significantly influencing the overall survival time of patients.This study aims to enhance the risk-assessment strategy for AL following gastrectomy for gastric cancer.Methods:This study included a derivation cohort and validation cohort.The derivation cohort included patients who underwent radical gastrectomy at Sir Run Run Shaw Hospital,Zhejiang University School of Medicine,from January 1,2015 to December 31,2020.An evidence-based predictor questionnaire was crafted through extensive literature review and panel discussions.Based on the questionnaire,inpatient data were collected to form a model-derivation cohort.This cohort underwent both univariate and multivariate analyses to identify factors associated with AL events,and a logistic regression model with stepwise regression was developed.A 5-fold cross-validation ensured model reliability.The validation cohort included patients from August 1,2021 to December 31,2021 at the same hospital.Using the same imputation method,we organized the validation-queue data.We then employed the risk-prediction model constructed in the earlier phase of the study to predict the risk of AL in the subjects included in the validation queue.We compared the predictions with the actual occurrence,and evaluated the external validation performance of the model using model-evaluation indicators such as the area under the receiver operating characteristic curve(AUROC),Brier score,and calibration curve.Results:The derivation cohort included 1377 patients,and the validation cohort included 131 patients.The independent predictors of AL after radical gastrectomy included age65 y,preoperative albumin<35 g/L,resection extent,operative time240 min,and intraoperative blood loss90 mL.The predictive model exhibited a solid AUROC of 0.750(95%CI:0.694e0.806;p<0.001)with a Brier score of 0.049.The 5-fold cross-validation confirmed these findings with a calibrated C-index of 0.749 and an average Brier score of 0.052.External validation showed an AUROC of 0.723(95%CI:0.564e0.882;p?0.006)and a Brier score of 0.055,confirming reliability in different clinical settings.Conclusions:We successfully developed a risk-prediction model for AL following radical gastrectomy.This tool will aid healthcare professionals in anticipating AL,potentially reducing unnecessary interventions. 展开更多
关键词 Stomach neoplasms Anastomotic leak Risk factors Prediction model Risk assessment
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Bayesian network-based survival prediction model for patients having undergone post-transjugular intrahepatic portosystemic shunt for portal hypertension
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作者 Rong Chen Ling Luo +3 位作者 Yun-Zhi Zhang Zhen Liu An-Lin Liu Yi-Wen Zhang 《World Journal of Gastroenterology》 SCIE CAS 2024年第13期1859-1870,共12页
BACKGROUND Portal hypertension(PHT),primarily induced by cirrhosis,manifests severe symptoms impacting patient survival.Although transjugular intrahepatic portosystemic shunt(TIPS)is a critical intervention for managi... BACKGROUND Portal hypertension(PHT),primarily induced by cirrhosis,manifests severe symptoms impacting patient survival.Although transjugular intrahepatic portosystemic shunt(TIPS)is a critical intervention for managing PHT,it carries risks like hepatic encephalopathy,thus affecting patient survival prognosis.To our knowledge,existing prognostic models for post-TIPS survival in patients with PHT fail to account for the interplay among and collective impact of various prognostic factors on outcomes.Consequently,the development of an innovative modeling approach is essential to address this limitation.AIM To develop and validate a Bayesian network(BN)-based survival prediction model for patients with cirrhosis-induced PHT having undergone TIPS.METHODS The clinical data of 393 patients with cirrhosis-induced PHT who underwent TIPS surgery at the Second Affiliated Hospital of Chongqing Medical University between January 2015 and May 2022 were retrospectively analyzed.Variables were selected using Cox and least absolute shrinkage and selection operator regression methods,and a BN-based model was established and evaluated to predict survival in patients having undergone TIPS surgery for PHT.RESULTS Variable selection revealed the following as key factors impacting survival:age,ascites,hypertension,indications for TIPS,postoperative portal vein pressure(post-PVP),aspartate aminotransferase,alkaline phosphatase,total bilirubin,prealbumin,the Child-Pugh grade,and the model for end-stage liver disease(MELD)score.Based on the above-mentioned variables,a BN-based 2-year survival prognostic prediction model was constructed,which identified the following factors to be directly linked to the survival time:age,ascites,indications for TIPS,concurrent hypertension,post-PVP,the Child-Pugh grade,and the MELD score.The Bayesian information criterion was 3589.04,and 10-fold cross-validation indicated an average log-likelihood loss of 5.55 with a standard deviation of 0.16.The model’s accuracy,precision,recall,and F1 score were 0.90,0.92,0.97,and 0.95 respectively,with the area under the receiver operating characteristic curve being 0.72.CONCLUSION This study successfully developed a BN-based survival prediction model with good predictive capabilities.It offers valuable insights for treatment strategies and prognostic evaluations in patients having undergone TIPS surgery for PHT. 展开更多
关键词 Bayesian network CIRRHOSIS Portal hypertension Transjugular intrahepatic portosystemic shunt Survival prediction model
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Gated Neural Network-Based Unsteady Aerodynamic Modeling for Large Angles of Attack
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作者 DENG Yongtao CHENG Shixin MI Baigang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第4期432-443,共12页
Modeling of unsteady aerodynamic loads at high angles of attack using a small amount of experimental or simulation data to construct predictive models for unknown states can greatly improve the efficiency of aircraft ... Modeling of unsteady aerodynamic loads at high angles of attack using a small amount of experimental or simulation data to construct predictive models for unknown states can greatly improve the efficiency of aircraft unsteady aerodynamic design and flight dynamics analysis.In this paper,aiming at the problems of poor generalization of traditional aerodynamic models and intelligent models,an intelligent aerodynamic modeling method based on gated neural units is proposed.The time memory characteristics of the gated neural unit is fully utilized,thus the nonlinear flow field characterization ability of the learning and training process is enhanced,and the generalization ability of the whole prediction model is improved.The prediction and verification of the model are carried out under the maneuvering flight condition of NACA0015 airfoil.The results show that the model has good adaptability.In the interpolation prediction,the maximum prediction error of the lift and drag coefficients and the moment coefficient does not exceed 10%,which can basically represent the variation characteristics of the entire flow field.In the construction of extrapolation models,the training model based on the strong nonlinear data has good accuracy for weak nonlinear prediction.Furthermore,the error is larger,even exceeding 20%,which indicates that the extrapolation and generalization capabilities need to be further optimized by integrating physical models.Compared with the conventional state space equation model,the proposed method can improve the extrapolation accuracy and efficiency by 78%and 60%,respectively,which demonstrates the applied potential of this method in aerodynamic modeling. 展开更多
关键词 large angle of attack unsteady aerodynamic modeling gated neural networks generalization ability
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The Effectiveness of the Havriliak-Negami Model in Predicting the Master Curves of the Asphalt Blends with SBS Triblock Copolymer and Organic-Montmorillonite at Different Temperatures and Frequencies
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作者 María Ángeles Vargas-Hernández Miguel Ángel Vargas +1 位作者 Pedro R. García-Morán Humberto Vázquez-Torres 《Journal of Materials Science and Chemical Engineering》 2024年第7期23-39,共17页
The dynamic viscoelastic properties of asphalt AC-20 and its composites with Organic-Montmorillonite clay (OMMt) and SBS were modeled using the empirical Havriliak-Negami (HN) model, based on linear viscoelastic theor... The dynamic viscoelastic properties of asphalt AC-20 and its composites with Organic-Montmorillonite clay (OMMt) and SBS were modeled using the empirical Havriliak-Negami (HN) model, based on linear viscoelastic theory (LVE). The HN parameters, α, β, G0, G∞and τHN were determined by solving the HN equation across various temperatures and frequencies. The HN model successfully predicted the rheological behavior of the asphalt and its blends within the temperature range of 25˚C - 40˚C. However, deviations occurred between 40˚C - 75˚C, where the glass transition temperature Tg of the asphalt components and the SBS polymer are located, rendering the HN model ineffective for predicting the dynamic viscoelastic properties of composites containing OMMt under these conditions. Yet, the prediction error of the HN model dropped to 2.28% - 2.81% for asphalt and its mixtures at 100˚C, a temperature exceeding the Tg values of both polymer and asphalt, where the mixtures exhibited a liquid-like behavior. The exponent α and the relaxation time increased with temperature across all systems. Incorporating OMMt clay into the asphalt blends significantly enhanced the relaxation dynamics of the resulting composites. 展开更多
关键词 ASPHALT BLENDS Master Curve Linear Viscoelasticity Havriliak-Negami model
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Application of Elzaki Transform Method to Market Volatility Using the Black-Scholes Model
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作者 Henrietta Ify Ojarikre Ideh Rapheal Ebimene James Mamadu 《Journal of Applied Mathematics and Physics》 2024年第3期819-828,共10页
Black-Scholes Model (B-SM) simulates the dynamics of financial market and contains instruments such as options and puts which are major indices requiring solution. B-SM is known to estimate the correct prices of Europ... Black-Scholes Model (B-SM) simulates the dynamics of financial market and contains instruments such as options and puts which are major indices requiring solution. B-SM is known to estimate the correct prices of European Stock options and establish the theoretical foundation for Option pricing. Therefore, this paper evaluates the Black-Schole model in simulating the European call in a cash flow in the dependent drift and focuses on obtaining analytic and then approximate solution for the model. The work also examines Fokker Planck Equation (FPE) and extracts the link between FPE and B-SM for non equilibrium systems. The B-SM is then solved via the Elzaki transform method (ETM). The computational procedures were obtained using MAPLE 18 with the solution provided in the form of convergent series. 展开更多
关键词 Elzaki Transform Method European Call Black-Scholes model Fokker-Planck Equation Market Volatility
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Physical model test and application of 3D printing rock-like specimens to laminated rock tunnels
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作者 Yun Tian Weizhong Chen +3 位作者 Hongming Tian Xiaoyun Shu Linkai He Man Huang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第11期4625-4637,共13页
Weak structural plane deformation is responsible for the non-uniform large deformation disasters in layered rock tunnels,resulting in steel arch distortion and secondary lining cracking.In this study,a servo biaxial t... Weak structural plane deformation is responsible for the non-uniform large deformation disasters in layered rock tunnels,resulting in steel arch distortion and secondary lining cracking.In this study,a servo biaxial testing system was employed to conduct physical modeling tests on layered rock tunnels with bedding planes of varying dip angles.The influence of structural anisotropy in layered rocks on the micro displacement and strain field of surrounding rocks was analyzed using digital image correlation(DIC)technology.The spatiotemporal evolution of non-uniform deformation of surrounding rocks was investigated,and numerical simulation was performed to verify the experimental results.The findings indicate that the displacement and strain field of the surrounding layered rocks are all maximized at the horizontal bedding planes and decrease linearly with the increasing dip angle.The failure of the layered surrounding rock with different dip angles occurs and extends along the bedding planes.Compressive strain failure occurs after excavation under high horizontal stress.This study provides significant theoretical support for the analysis,prediction,and control of non-uniform deformation of tunnel surrounding rocks. 展开更多
关键词 Bedding plane Three-dimensional(3D)printing Physical model test Non-uniform deformation Digital imaging correlation(DIC)
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基于数据流的K-S变化检测的动态多目标规划算法 被引量:1
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作者 张涛 周晨 +2 位作者 杜锋 陈芳 刘瑞林 《长江大学学报(自然科学版)》 2024年第1期109-116,共8页
为了更加准确地判断环境是否发生变化并快速追踪动态多目标规划问题(dynamicmulti-objectiveoptimization problem,DMOP)当前时刻的Pareto前沿,提出了一种基于数据流的Kolmogorov-Smirnov(K-S)变化检测的动态多目标规划(DSK-SDMOP)算法... 为了更加准确地判断环境是否发生变化并快速追踪动态多目标规划问题(dynamicmulti-objectiveoptimization problem,DMOP)当前时刻的Pareto前沿,提出了一种基于数据流的Kolmogorov-Smirnov(K-S)变化检测的动态多目标规划(DSK-SDMOP)算法。该算法以NSGA-Ⅱ为基础,通过数据流建立2个时刻的检验窗口,再利用K-S检验基于数据流的Pareto最优前沿是否发生变化,检测2个窗口的数据是否服从同一分布来判断环境是否发生变化,并就环境变化的剧烈程度实行相应的应答机制,以提高对环境的适应程度。利用基于数据流的K-S检测方法,对环境变化不会过于敏感,而且不用提前假设对应目标值的分布,易于操作。通过5个动态多目标规划标准测试函数对该算法进行测试,并和现有的2种算法进行对比分析,结果表明该算法处理动态多目标规划问题具有良好的性能。 展开更多
关键词 动态多目标规划 数据流 k-S检验 NSGA-Ⅱ
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K-S变换及其电网超谐波时频分析应用
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作者 滕召胜 梁成斌 +2 位作者 唐求 张雷鹏 成达 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第6期128-136,共9页
依据FFT→优化窗→IFFT思路,突破线性时频变换的窗函数积分性能桎梏,实现高性能优化窗函数的线性时频变换应用,建立新型时频变换算法——K-S变换.对信号x(t)的FFT频谱向量进行频移处理后,与该频移点下Kaiser优化窗的频谱向量进行Hadamar... 依据FFT→优化窗→IFFT思路,突破线性时频变换的窗函数积分性能桎梏,实现高性能优化窗函数的线性时频变换应用,建立新型时频变换算法——K-S变换.对信号x(t)的FFT频谱向量进行频移处理后,与该频移点下Kaiser优化窗的频谱向量进行Hadamard乘积,再将乘积结果进行FFT逆变换(IFFT),构造出K-S变换复时频矩阵,由此获得x(t)的时间-频率-幅值、时间-频率-相位三维信息;给出逆变换的数学推导与局部性质、线性性质和变分辨率特性;0~150 kHz电网的稳态与时变超谐波信号仿真实验表明,K-S变换的时域、频域分辨能力均优于流行的短时傅里叶变换、S变换,具有优良的变分辨率性能;0~40 kHz超谐波信号的实测证明,基于K-S变换的超谐波电压幅值测量绝对误差均小于0.032 3 V. 展开更多
关键词 k-S变换 时频分析 Kaiser优化窗 变分辨率特性 电网超谐波
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基于融合K-近邻算法的电压互感器在线监测方法
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作者 李振华 崔九喜 +3 位作者 杨信强 吴海荣 杨诗豪 薛田良 《电网技术》 EI CSCD 北大核心 2024年第9期3938-3947,I0100,共11页
由于受工作时长和环境因素的影响,电容式电压互感器(capacitor voltage transformer,CVT)在运行过程中误差稳定性不高,易出现电能计量失准现象。为此,该文提出了一种基于融合K-近邻算法(fusion K-nearest neighbor algorithm,FKNN)的电... 由于受工作时长和环境因素的影响,电容式电压互感器(capacitor voltage transformer,CVT)在运行过程中误差稳定性不高,易出现电能计量失准现象。为此,该文提出了一种基于融合K-近邻算法(fusion K-nearest neighbor algorithm,FKNN)的电压互感器在线评估方法。该方法利用互感器的历史运行数据构建虚拟标准器,通过改进K-近邻算法对互感器实时状态进行监测,实现对异常情况的报警。同时,提出了一种加权移动时间窗的方法,自适应更新异常阈值,有效削弱电网不平衡波动的影响。实验结果表明,该文方法能够准确监测互感器的0.2级误差漂移。 展开更多
关键词 电压互感器 虚拟标准器 k-近邻算法 自适应更新
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基于数字孪生与k-近邻算法的车间设备运行状态预测研究
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作者 和征 李忠鹏 杨小红 《制造技术与机床》 北大核心 2024年第3期193-199,共7页
由于传统车间设备运行状态预测不能有效利用历史数据进行学习,实时响应能力有限,难以在复杂调度环境中取得良好效果,因此文章提出一种数字孪生与k-近邻算法相结合的车间设备运行状态预测模型。构建车间设备实体在信息空间的数字孪生模型... 由于传统车间设备运行状态预测不能有效利用历史数据进行学习,实时响应能力有限,难以在复杂调度环境中取得良好效果,因此文章提出一种数字孪生与k-近邻算法相结合的车间设备运行状态预测模型。构建车间设备实体在信息空间的数字孪生模型,并建立设备实体与模型之间的映射关系,从而获取实时特征数据,即设备的运行状态特征数据。运用k-近邻算法计算实时特征数据与历史数据之间的欧几里得距离,即计算设备当前运行状态与历史已知状态的相似度,最终通过前k个距离所对应的设备历史运行状态数据,预测设备的当前运行状态。该模型的本质是通过数字孪生的实时数据采集,获取指定设备运行状态特征数据,运用k-近邻算法预测设备的实时运行状态。相较以往研究,本研究贡献在于提高设备实时运行状态预测的准确率。如果将数字孪生、k-近邻算法与具备自我学习能力的相关算法相结合,模型的预测效果会更好。 展开更多
关键词 k-近邻算法 机器学习 数字孪生 车间设备运行状态预测
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采用STAMP-24Model的多组织事故分析
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作者 曾明荣 秦永莹 +2 位作者 刘小航 栗婧 尚长岭 《安全与环境学报》 CAS CSCD 北大核心 2024年第7期2741-2750,共10页
安全生产事故往往由多组织交互、多因素耦合造成,事故原因涉及多个组织。为预防和遏制多组织生产安全事故的发生,基于系统理论事故建模与过程模型(Systems-Theory Accident Modeling and Process,STAMP)、24Model,构建一种用于多组织事... 安全生产事故往往由多组织交互、多因素耦合造成,事故原因涉及多个组织。为预防和遏制多组织生产安全事故的发生,基于系统理论事故建模与过程模型(Systems-Theory Accident Modeling and Process,STAMP)、24Model,构建一种用于多组织事故分析的方法,并以青岛石油爆炸事故为例进行事故原因分析。结果显示:STAMP-24Model可以分组织,分层次且有效、全面、详细地分析涉及多个组织的事故原因,探究多组织之间的交互关系;对事故进行动态演化分析,可得到各组织不安全动作耦合关系与形成的事故失效链及管控失效路径,进而为预防多组织事故提供思路和参考。 展开更多
关键词 安全工程 系统理论事故建模与过程模型(STAMP) 24model 多组织事故 原因分析
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试论美国K-12公立学校课程中的种族批判理论之争
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作者 吴路珂 杨捷 《外国教育研究》 CSSCI 北大核心 2024年第8期20-34,共15页
近年来,种族批判理论开始走进美国K-12公立学校课程,成为培育学生社会情感能力、维护教育公平的一种路径。然而,伴随种族矛盾加剧和民粹主义抬头,美国社会围绕种族批判理论在K-12公立学校课程中的存废问题展开激烈争论。反对者指责该理... 近年来,种族批判理论开始走进美国K-12公立学校课程,成为培育学生社会情感能力、维护教育公平的一种路径。然而,伴随种族矛盾加剧和民粹主义抬头,美国社会围绕种族批判理论在K-12公立学校课程中的存废问题展开激烈争论。反对者指责该理论妨害学生的种族身份认知,曲解美国历史,破坏社会共识;支持者则认为该理论能够提升学生多元文化意识,增强种族和历史问题的课堂对话。这场以种族批判理论为核心的课程博弈,反映了当前美国两党在公共教育领域对意识形态主导权的竞争。美国K-12公立学校需要认清既有课程治理措施的缺失,及时清除影响课程设置的认知偏见,进一步拓展具有文化相关性的课程空间。 展开更多
关键词 美国 k-12公立学校 种族批判理论 课程设置 种族主义 政治极化 文化响应
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一种分配查询的k-匿名位置隐私保护方案
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作者 宋成 王治超 杨囡囡 《重庆邮电大学学报(自然科学版)》 CSCD 北大核心 2024年第2期367-373,共7页
针对基于位置服务中移动终端用户位置隐私保护存在时空关联和背景知识攻击的问题,提出一种分配查询的k-匿名位置隐私保护方案。基于查询概率和欧氏距离,在相邻网格区域内筛选假位置,合并真实用户位置形成k-匿名;通过兴趣点语义四叉树为... 针对基于位置服务中移动终端用户位置隐私保护存在时空关联和背景知识攻击的问题,提出一种分配查询的k-匿名位置隐私保护方案。基于查询概率和欧氏距离,在相邻网格区域内筛选假位置,合并真实用户位置形成k-匿名;通过兴趣点语义四叉树为假位置分配合理的查询,从时间、位置及查询3个维度提升用户被识别的不确定性,从而增强用户隐私度。安全性分析表明,提出的方案满足匿名性、不可伪造性和抵抗查询服务跟踪等安全特性。仿真实验表明,提出的方案具有较高的隐私保护度和效率以及较低的通信开销。 展开更多
关键词 位置隐私 k-匿名 分配查询 隐私保护
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基于改进24Model-ISM-SNA建筑工人不安全行为关联路径研究
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作者 赵平 刘钰 +1 位作者 靳丽艳 王佳慧 《工业安全与环保》 2024年第7期37-40,共4页
建筑施工现场环境复杂,为有效控制不安全行为发生,基于行为安全“2-4”模型对360份具有代表性的建筑安全事故调查报告进行分析,提取出22个不安全行为的主要影响因素。利用灰色关联分析方法(GRA)改进的集成ISM-SNA模型,将不安全行为风险... 建筑施工现场环境复杂,为有效控制不安全行为发生,基于行为安全“2-4”模型对360份具有代表性的建筑安全事故调查报告进行分析,提取出22个不安全行为的主要影响因素。利用灰色关联分析方法(GRA)改进的集成ISM-SNA模型,将不安全行为风险因素划分为表层、过渡层与深层,然后对风险因素进行可视化分析、中心度分析及凝聚子群分析,揭示了各致因因素间的关联关系和传导路径。结果表明,建筑工人不安全行为影响因素可划分成7级3阶的多级递阶结构,安全意识、现场监管、外部环境是建筑工人不安全行为的关键影响因素,同时现场监管和隐患排查到位能有效降低不安全行为的发生。 展开更多
关键词 建筑工人 不安全行为 24model 解释结构模型(ISM) 社会网络分析(SNA)
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美国K-12“天才时刻”项目与学生创新素养培养
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作者 李先军 赵新琪 《比较教育学报》 CSSCI 北大核心 2024年第4期77-89,共13页
为建设教育强国,拔尖创新人才受到社会各界高度重视,但我国对拔尖创新人才的关注主要集中在高等教育阶段,对基础教育阶段学生创新素养的关注不足。而美国K-12“天才时刻”项目的核心理念是通过创建探究式的学习活动,培养学生以创造性思... 为建设教育强国,拔尖创新人才受到社会各界高度重视,但我国对拔尖创新人才的关注主要集中在高等教育阶段,对基础教育阶段学生创新素养的关注不足。而美国K-12“天才时刻”项目的核心理念是通过创建探究式的学习活动,培养学生以创造性思维为主的高阶思维技能。“天才时刻”项目的主要做法为:创设自由支持的环境;为学生提供个性化的学习指导;以及引导学生重视项目的反思与自我评价等。研究表明,“天才时刻”项目促进了中小学生创新素养的发展。为培养我国中小学生的创新素养,学校应创建有利于学生创新人格培养的学习氛围;为学生提供个性化的自由发展创新思维的机会;引导学生反思创新实践的过程与自我评价。 展开更多
关键词 美国 “天才时刻”项目 创新素养 拔尖创新人才 k-12
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基于24Model的地铁内涝事故原因分析与评估
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作者 张江石 胡馨月 +3 位作者 侯轩 李泳暾 李梓萌 高进东 《安全与环境工程》 CAS CSCD 北大核心 2024年第6期111-117,共7页
为降低地铁内涝事故灾害风险,基于事故致因“2-4”模型,分析了地铁内涝事故致灾因子,采用层次分析法构建了地铁内涝事故原因分析指标体系,确定了各风险因子的权重,并利用模糊综合评价法对地铁内涝事故进行了定量评估,识别出关键的影响... 为降低地铁内涝事故灾害风险,基于事故致因“2-4”模型,分析了地铁内涝事故致灾因子,采用层次分析法构建了地铁内涝事故原因分析指标体系,确定了各风险因子的权重,并利用模糊综合评价法对地铁内涝事故进行了定量评估,识别出关键的影响因素。结果表明:地铁内涝事故一级指标中不安全动作与物态因素最重要,其中影响最大的指标包括擅自更改建筑设计、未按照要求检查水位情况、未及时排水、出入口不符合防汛标准等因素;习惯性不安全行为的权重位居第二,表明该指标因素较为重要,同时安全管理体系得分位居第二,表明该指标因素较易发生。对关键指标采取防范措施,可有效降低风险,从而减少地铁内涝事故的发生。 展开更多
关键词 安全工程 地铁内涝 24model 层次分析法 模糊综合评价法
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基于24Model-D-ISM的地铁站火灾疏散影响因素研究
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作者 孙世梅 张家严 《中国安全科学学报》 CAS CSCD 北大核心 2024年第4期153-159,共7页
为预防地铁站火灾事故,深入了解地铁站火灾人员疏散影响因素间的内在联系与层次结构,基于第6版“2-4”模型(24Model)分析63起地铁站火灾疏散事故,充分考虑各个因素之间的交互作用,提取19个影响地铁站人员疏散的关键因素,建立地铁站火灾... 为预防地铁站火灾事故,深入了解地铁站火灾人员疏散影响因素间的内在联系与层次结构,基于第6版“2-4”模型(24Model)分析63起地铁站火灾疏散事故,充分考虑各个因素之间的交互作用,提取19个影响地铁站人员疏散的关键因素,建立地铁站火灾人员疏散影响因素指标体系;采用算子客观赋权法(C-OWA)改进决策试验与评价实验法(DEMATEL),确定地铁站火灾人员疏散的重要影响因素;在此基础上,采用解释结构模型(ISM)分析各个因素间的层次结构及相互作用路径,构建地铁站火灾人员疏散影响因素的多级递阶结构模型。研究结果表明:疏散引导、恐慌从众行为、人员拥挤为地铁站火灾人员疏散的关键影响因素;地铁站火灾人员疏散受表层因素、中间层因素、深层因素共同作用的影响,其中,疏散教育与培训、设施维护与检查、疏散预案等因素是根源影响因素,重视根源影响因素的改善有利于从本质上预防和控制事故的发生。 展开更多
关键词 “2-4”模型(24model) 决策试验与评价实验法(DEMATEL) 解释结构模型(ISM) 地铁站 火灾疏散 影响因素
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K-凸函数的性质
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作者 万莉娟 佟浩 +1 位作者 吴葛 赵欣 《齐齐哈尔大学学报(自然科学版)》 2024年第4期91-94,共4页
借助集值映射的K-回收映射和K-雅可比映射得到了K-凸函数的两个性质。
关键词 k-凸函数 k-回收锥 k-回收映射 k-雅可比映射
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