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A real-time intelligent lithology identification method based on a dynamic felling strategy weighted random forest algorithm
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作者 Tie Yan Rui Xu +2 位作者 Shi-Hui Sun Zhao-Kai Hou Jin-Yu Feng 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1135-1148,共14页
Real-time intelligent lithology identification while drilling is vital to realizing downhole closed-loop drilling. The complex and changeable geological environment in the drilling makes lithology identification face ... Real-time intelligent lithology identification while drilling is vital to realizing downhole closed-loop drilling. The complex and changeable geological environment in the drilling makes lithology identification face many challenges. This paper studies the problems of difficult feature information extraction,low precision of thin-layer identification and limited applicability of the model in intelligent lithologic identification. The author tries to improve the comprehensive performance of the lithology identification model from three aspects: data feature extraction, class balance, and model design. A new real-time intelligent lithology identification model of dynamic felling strategy weighted random forest algorithm(DFW-RF) is proposed. According to the feature selection results, gamma ray and 2 MHz phase resistivity are the logging while drilling(LWD) parameters that significantly influence lithology identification. The comprehensive performance of the DFW-RF lithology identification model has been verified in the application of 3 wells in different areas. By comparing the prediction results of five typical lithology identification algorithms, the DFW-RF model has a higher lithology identification accuracy rate and F1 score. This model improves the identification accuracy of thin-layer lithology and is effective and feasible in different geological environments. The DFW-RF model plays a truly efficient role in the realtime intelligent identification of lithologic information in closed-loop drilling and has greater applicability, which is worthy of being widely used in logging interpretation. 展开更多
关键词 Intelligent drilling Closed-loop drilling Lithology identification random forest algorithm Feature extraction
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Investigation of Nuclear Binding Energy and Charge Radius Based on Random Forest Algorithm
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作者 CAI Boshuai YU Tianjun +3 位作者 LIN Xuan ZHANG Jilong WANG Zhixuan YUAN Cenxi 《原子能科学技术》 EI CAS CSCD 北大核心 2023年第4期704-712,共9页
The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE ... The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model. 展开更多
关键词 nuclear binding energy nuclear charge radius random forest algorithm
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Winter Wheat Yield Estimation Based on Sparrow Search Algorithm Combined with Random Forest:A Case Study in Henan Province,China
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作者 SHI Xiaoliang CHEN Jiajun +2 位作者 DING Hao YANG Yuanqi ZHANG Yan 《Chinese Geographical Science》 SCIE CSCD 2024年第2期342-356,共15页
Precise and timely prediction of crop yields is crucial for food security and the development of agricultural policies.However,crop yield is influenced by multiple factors within complex growth environments.Previous r... Precise and timely prediction of crop yields is crucial for food security and the development of agricultural policies.However,crop yield is influenced by multiple factors within complex growth environments.Previous research has paid relatively little attention to the interference of environmental factors and drought on the growth of winter wheat.Therefore,there is an urgent need for more effective methods to explore the inherent relationship between these factors and crop yield,making precise yield prediction increasingly important.This study was based on four type of indicators including meteorological,crop growth status,environmental,and drought index,from October 2003 to June 2019 in Henan Province as the basic data for predicting winter wheat yield.Using the sparrow search al-gorithm combined with random forest(SSA-RF)under different input indicators,accuracy of winter wheat yield estimation was calcu-lated.The estimation accuracy of SSA-RF was compared with partial least squares regression(PLSR),extreme gradient boosting(XG-Boost),and random forest(RF)models.Finally,the determined optimal yield estimation method was used to predict winter wheat yield in three typical years.Following are the findings:1)the SSA-RF demonstrates superior performance in estimating winter wheat yield compared to other algorithms.The best yield estimation method is achieved by four types indicators’composition with SSA-RF)(R^(2)=0.805,RRMSE=9.9%.2)Crops growth status and environmental indicators play significant roles in wheat yield estimation,accounting for 46%and 22%of the yield importance among all indicators,respectively.3)Selecting indicators from October to April of the follow-ing year yielded the highest accuracy in winter wheat yield estimation,with an R^(2)of 0.826 and an RMSE of 9.0%.Yield estimates can be completed two months before the winter wheat harvest in June.4)The predicted performance will be slightly affected by severe drought.Compared with severe drought year(2011)(R^(2)=0.680)and normal year(2017)(R^(2)=0.790),the SSA-RF model has higher prediction accuracy for wet year(2018)(R^(2)=0.820).This study could provide an innovative approach for remote sensing estimation of winter wheat yield.yield. 展开更多
关键词 winter wheat yield estimation sparrow search algorithm combined with random forest(SSA-RF) machine learning multi-source indicator optimal lead time Henan Province China
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Object-based classification of hyperspectral data using Random Forest algorithm 被引量:2
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作者 Saeid Amini Saeid Homayouni +1 位作者 Abdolreza Safari Ali A.Darvishsefat 《Geo-Spatial Information Science》 SCIE CSCD 2018年第2期127-138,共12页
This paper presents a new framework for object-based classification of high-resolution hyperspectral data.This multi-step framework is based on multi-resolution segmentation(MRS)and Random Forest classifier(RFC)algori... This paper presents a new framework for object-based classification of high-resolution hyperspectral data.This multi-step framework is based on multi-resolution segmentation(MRS)and Random Forest classifier(RFC)algorithms.The first step is to determine of weights of the input features while using the object-based approach with MRS to processing such images.Given the high number of input features,an automatic method is needed for estimation of this parameter.Moreover,we used the Variable Importance(VI),one of the outputs of the RFC,to determine the importance of each image band.Then,based on this parameter and other required parameters,the image is segmented into some homogenous regions.Finally,the RFC is carried out based on the characteristics of segments for converting them into meaningful objects.The proposed method,as well as,the conventional pixel-based RFC and Support Vector Machine(SVM)method was applied to three different hyperspectral data-sets with various spectral and spatial characteristics.These data were acquired by the HyMap,the Airborne Prism Experiment(APEX),and the Compact Airborne Spectrographic Imager(CASI)hyperspectral sensors.The experimental results show that the proposed method is more consistent for land cover mapping in various areas.The overall classification accuracy(OA),obtained by the proposed method was 95.48,86.57,and 84.29%for the HyMap,the APEX,and the CASI datasets,respectively.Moreover,this method showed better efficiency in comparison to the spectralbased classifications because the OAs of the proposed method was 5.67 and 3.75%higher than the conventional RFC and SVM classifiers,respectively. 展开更多
关键词 Object-based classification random forest algorithm multi-resolution segmentation(MRS) hyperspectral imagery
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Improved Random Forest Algorithm Based on Adaptive Step Size Artificial Bee Colony Optimization
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作者 Jiuyuan Huo Xuan Qin +2 位作者 Hamzah Murad Mohammed Al-Neshmi Lin Mu Tao Ju 《国际计算机前沿大会会议论文集》 2020年第2期216-233,共18页
The traditional random forest algorithm works along with unbalanced data,cannot achieve satisfactory prediction results for minority class,and suffers from the parameter selection dilemma.In view of this problem,this ... The traditional random forest algorithm works along with unbalanced data,cannot achieve satisfactory prediction results for minority class,and suffers from the parameter selection dilemma.In view of this problem,this paper proposes an unbalanced accuracy weighted random forest algorithm(UAW_RF)based on the adaptive step size artificial bee colony optimization.It combines the ideas of decision tree optimization,sampling selection,and weighted voting to improve the ability of stochastic forest algorithm when dealing with biased data classification.The adaptive step size and the optimal solution were introduced to improve the position updating formula of the artificial bee colony algorithm,and then the parameter combination of the random forest algorithm was iteratively optimized with the advantages of the algorithm.Experimental results show satisfactory accuracies and prove that the method can effectively improve the classification accuracy of the random forest algorithm. 展开更多
关键词 random forest algorithm Artificial bee colony algorithm Unbalanced data Classification problem
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Random forest algorithm and regional applications of spectral inversion model for estimating canopy nitrogen concentration in rice 被引量:1
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作者 LI Xuqing LIU Xiangnan LIU Meiling WU Ling 《遥感学报》 CSCD 北大核心 2014年第4期923-945,共23页
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The Comparison between Random Forest and Support Vector Machine Algorithm for Predicting β-Hairpin Motifs in Proteins
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作者 Shaochun Jia Xiuzhen Hu Lixia Sun 《Engineering(科研)》 2013年第10期391-395,共5页
Based on the research of predictingβ-hairpin motifs in proteins, we apply Random Forest and Support Vector Machine algorithm to predictβ-hairpin motifs in ArchDB40 dataset. The motifs with the loop length of 2 to 8 ... Based on the research of predictingβ-hairpin motifs in proteins, we apply Random Forest and Support Vector Machine algorithm to predictβ-hairpin motifs in ArchDB40 dataset. The motifs with the loop length of 2 to 8 amino acid residues are extracted as research object and thefixed-length pattern of 12 amino acids are selected. When using the same characteristic parameters and the same test method, Random Forest algorithm is more effective than Support Vector Machine. In addition, because of Random Forest algorithm doesn’t produce overfitting phenomenon while the dimension of characteristic parameters is higher, we use Random Forest based on higher dimension characteristic parameters to predictβ-hairpin motifs. The better prediction results are obtained;the overall accuracy and Matthew’s correlation coefficient of 5-fold cross-validation achieve 83.3% and 0.59, respectively. 展开更多
关键词 random forest algorithm Support Vector Machine algorithm β-Hairpin MOTIF INCREMENT of Diversity SCORING Function Predicted Secondary Structure Information
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Companies’ E-waste Estimation Based on General Equilibrium The­ory Context and Random Forest Regression Algorithm in Cameroon: Case Study of SMEs Implementing ISO 14001:2015
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作者 Gilson Tekendo Djoukoue Idriss Djiofack Teledjieu Sijun Bai 《Journal of Management Science & Engineering Research》 2023年第2期60-81,共22页
Given the challenge of estimating or calculating quantities of waste electrical and electronic equipment(WEEE)in developing countries,this article focuses on predicting the WEEE generated by Cameroonian small and medi... Given the challenge of estimating or calculating quantities of waste electrical and electronic equipment(WEEE)in developing countries,this article focuses on predicting the WEEE generated by Cameroonian small and medium enterprises(SMEs)that are engaged in ISO 14001:2015 initiatives and consume electrical and electronic equipment(EEE)to enhance their performance and profitability.The methodology employed an exploratory approach involving the application of general equilibrium theory(GET)to contextualize the study and generate relevant parameters for deploying the random forest regression learning algorithm for predictions.Machine learning was applied to 80%of the samples for training,while simulation was conducted on the remaining 20%of samples based on quantities of EEE utilized over a specific period,utilization rates,repair rates,and average lifespans.The results demonstrate that the model’s predicted values are significantly close to the actual quantities of generated WEEE,and the model’s performance was evaluated using the mean squared error(MSE)and yielding satisfactory results.Based on this model,both companies and stakeholders can set realistic objectives for managing companies’WEEE,fostering sustainable socio-environmental practices. 展开更多
关键词 Electrical and electronic equipment(EEE) Waste from electrical and electronic equipment(WEEE) General equilibrium theory random forest regression algorithm DECISION-MAKING Cameroon
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Basic Tenets of Classification Algorithms K-Nearest-Neighbor, Support Vector Machine, Random Forest and Neural Network: A Review 被引量:4
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作者 Ernest Yeboah Boateng Joseph Otoo Daniel A. Abaye 《Journal of Data Analysis and Information Processing》 2020年第4期341-357,共17页
In this paper, sixty-eight research articles published between 2000 and 2017 as well as textbooks which employed four classification algorithms: K-Nearest-Neighbor (KNN), Support Vector Machines (SVM), Random Forest (... In this paper, sixty-eight research articles published between 2000 and 2017 as well as textbooks which employed four classification algorithms: K-Nearest-Neighbor (KNN), Support Vector Machines (SVM), Random Forest (RF) and Neural Network (NN) as the main statistical tools were reviewed. The aim was to examine and compare these nonparametric classification methods on the following attributes: robustness to training data, sensitivity to changes, data fitting, stability, ability to handle large data sizes, sensitivity to noise, time invested in parameter tuning, and accuracy. The performances, strengths and shortcomings of each of the algorithms were examined, and finally, a conclusion was arrived at on which one has higher performance. It was evident from the literature reviewed that RF is too sensitive to small changes in the training dataset and is occasionally unstable and tends to overfit in the model. KNN is easy to implement and understand but has a major drawback of becoming significantly slow as the size of the data in use grows, while the ideal value of K for the KNN classifier is difficult to set. SVM and RF are insensitive to noise or overtraining, which shows their ability in dealing with unbalanced data. Larger input datasets will lengthen classification times for NN and KNN more than for SVM and RF. Among these nonparametric classification methods, NN has the potential to become a more widely used classification algorithm, but because of their time-consuming parameter tuning procedure, high level of complexity in computational processing, the numerous types of NN architectures to choose from and the high number of algorithms used for training, most researchers recommend SVM and RF as easier and wieldy used methods which repeatedly achieve results with high accuracies and are often faster to implement. 展开更多
关键词 Classification algorithms NON-PARAMETRIC K-Nearest-Neighbor Neural Networks random forest Support Vector Machines
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Using machine learning algorithms to estimate stand volume growth of Larix and Quercus forests based on national-scale Forest Inventory data in China 被引量:2
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作者 Huiling Tian Jianhua Zhu +8 位作者 Xiao He Xinyun Chen Zunji Jian Chenyu Li Qiangxin Ou Qi Li Guosheng Huang Changfu Liu Wenfa Xiao 《Forest Ecosystems》 SCIE CSCD 2022年第3期396-406,共11页
Estimating the volume growth of forest ecosystems accurately is important for understanding carbon sequestration and achieving carbon neutrality goals.However,the key environmental factors affecting volume growth diff... Estimating the volume growth of forest ecosystems accurately is important for understanding carbon sequestration and achieving carbon neutrality goals.However,the key environmental factors affecting volume growth differ across various scales and plant functional types.This study was,therefore,conducted to estimate the volume growth of Larix and Quercus forests based on national-scale forestry inventory data in China and its influencing factors using random forest algorithms.The results showed that the model performances of volume growth in natural forests(R^(2)=0.65 for Larix and 0.66 for Quercus,respectively)were better than those in planted forests(R^(2)=0.44 for Larix and 0.40 for Quercus,respectively).In both natural and planted forests,the stand age showed a strong relative importance for volume growth(8.6%–66.2%),while the edaphic and climatic variables had a limited relative importance(<6.0%).The relationship between stand age and volume growth was unimodal in natural forests and linear increase in planted Quercus forests.And the specific locations(i.e.,altitude and aspect)of sampling plots exhibited high relative importance for volume growth in planted forests(4.1%–18.2%).Altitude positively affected volume growth in planted Larix forests but controlled volume growth negatively in planted Quercus forests.Similarly,the effects of other environmental factors on volume growth also differed in both stand origins(planted versus natural)and plant functional types(Larix versus Quercus).These results highlighted that the stand age was the most important predictor for volume growth and there were diverse effects of environmental factors on volume growth among stand origins and plant functional types.Our findings will provide a good framework for site-specific recommendations regarding the management practices necessary to maintain the volume growth in China's forest ecosystems. 展开更多
关键词 Stand volume growth Stand origin Plant functional type National forest inventory data random forest algorithms
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Multiscalar Geomorphometric Generalization for Soil-Landscape Modeling by Random Forest: A Case Study in the Eastern Amazon
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作者 Cauan Ferreira Araújo Raimundo Cosme de Oliveira Junior Troy Patrick Beldini 《Journal of Geographic Information System》 2021年第4期434-451,共18页
Multiscalar topography influence on soil distribution has a complex pattern that is related to overlay of pedological processes which occurred at different times, and these driving forces are correlated with many geom... Multiscalar topography influence on soil distribution has a complex pattern that is related to overlay of pedological processes which occurred at different times, and these driving forces are correlated with many geomorphologic scales. In this sense, the present study tested the hypothesis whether multiscale geomorphometric generalized covariables can improve pedometric modeling. To achieve this goal, this case study applied the Random Forest algorithm to a multiscale geomorphometric database to predict soil surface attributes. The study area is in phanerozoic sedimentary basins, in the Alter do Ch<span style="white-space:nowrap;">&#227;</span>o geological formation, Eastern Amazon, Brazil. The multiscale geomorphometric generalization was applied at general and specific geomorphometric covariables, producing groups for each scale combination. The modeling was run using Random Forest for A-horizon thickness, pH, silt and sand content. For model evaluation, visual analysis of digital maps, metrics of forest structures and effect of variables on prediction were used. For evaluation of soil textural classifications, the confusion matrix with a Kappa index, and the user’s and producer’s accuracies were employed. The geomorphometry generalization tends to smooth curvatures and produces identifiable geomorphic representations at sub-watershed and watershed levels. The forest structures and effect of variables on prediction are in agreement with pedological knowledge. The multiscale geomorphometric generalized covariables improved accuracy metrics of soil surface texture classification, with the Kappa Index going from 43% to 62%. Therefore, it can be argued that topography influences soil distribution at combined coarser spatial scales and is able to predict soil particle size contents in the studied watershed. Future development of the multiscale geomorphometric generalization framework could include generalization methods concerning preservation of features, landform classification adaptable at multiple scales. 展开更多
关键词 Digital Soil Mapping Upscaling Machine Learning random forest algorithm Multiscale Geomorphometric Generalization
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基于Isolation Forest和Random Forest相结合的智能电网时间序列数据异常检测算法 被引量:9
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作者 杨永娇 肖建毅 +1 位作者 赵创业 周开东 《计算机与现代化》 2020年第3期99-102,126,共5页
智能电网的信息系统是保障电力行业正常运行的基础,而智能电网中各种时间序列数据的分析结果是衡量信息系统稳定运行的重要依据。传统的时间序列数据异常检测算法很难同时兼顾准确性和实时性。本文引入基于Isolation Forest和Random For... 智能电网的信息系统是保障电力行业正常运行的基础,而智能电网中各种时间序列数据的分析结果是衡量信息系统稳定运行的重要依据。传统的时间序列数据异常检测算法很难同时兼顾准确性和实时性。本文引入基于Isolation Forest和Random Forest相结合的智能电网时间序列数据异常检测算法,结合无监督学习算法和有监督学习算法的优点,实现机器自动标注和自动学习阈值,人工标注少量特征值,从一定程度上提高了时间序列数据异常检查准确性和实时性,可以满足智能电网时间序列数据异常检测需求,从而达到提升智能电网信息安全的目的。 展开更多
关键词 Isolation forest算法 random forest算法 异常检测算法 时间序列数据 智能电网
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基于人工智能方法的隧道塌方风险预测研究 被引量:1
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作者 刘志锋 陈名煜 +1 位作者 吴修梅 魏振华 《水力发电》 CAS 2024年第3期31-38,共8页
为了对隧道塌方风险展开研究,整理246起隧道塌方事故案例,通过建立塌方风险评估指标体系,基于人工智能预测方法,分别采用随机森林算法、径向基函数神经网络、BP神经网络模型、粒子群算法优化BP神经网络模型,对塌方风险进行预测。结果表... 为了对隧道塌方风险展开研究,整理246起隧道塌方事故案例,通过建立塌方风险评估指标体系,基于人工智能预测方法,分别采用随机森林算法、径向基函数神经网络、BP神经网络模型、粒子群算法优化BP神经网络模型,对塌方风险进行预测。结果表明,随机森林算法、径向基函数神经网络、BP神经网络模型、粒子群算法优化BP神经网络模型的塌方预测准确率分别为81.67%、83.33%、86.67%、93.33%,F_(1)值分别为0.645、0.642、0.5、0.833。粒子群算法优化BP神经网络模型预测准确率和F_(1)值均大幅提高,预测效果最好,大大减少了评估结果的主观性,为隧道塌方风险研究提供了新的研究思路。 展开更多
关键词 隧道工程 塌方 风险预测 随机森林算法 径向基函数神经网络 BP神经网络 粒子群算法
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基于路面等级识别的车辆半主动悬架内外环控制 被引量:2
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作者 寇发荣 郭杨娟 +1 位作者 刘朋涛 门浩 《噪声与振动控制》 CSCD 北大核心 2024年第2期171-177,共7页
针对车辆在不同路面等级下对悬架动态性能与馈能特性需求不同的问题,提出一种基于RF-XGBoost路面等级识别算法的半主动悬架内外环控制策略。利用随机森林(Random Forest,RF)模型对极端梯度提升(Extreme Gradient Boosting,XGBoost)算法... 针对车辆在不同路面等级下对悬架动态性能与馈能特性需求不同的问题,提出一种基于RF-XGBoost路面等级识别算法的半主动悬架内外环控制策略。利用随机森林(Random Forest,RF)模型对极端梯度提升(Extreme Gradient Boosting,XGBoost)算法进行优化,搭建RF-XGBoost算法模型对路面等级进行识别。将路面等级与悬架控制策略相结合,设计外环为天地棚控制,内环为自适应滑模控制的内外环控制,实现非线性悬架的自适应控制。仿真结果表明,相比传统混合天地棚控制的悬架,内外环控制下的悬架在A级路面下簧载质量加速度降低15.52%,并实现50.4 W的振动能量回收,在B、C级路面下簧载质量加速度分别降低15.09%、16.72%,轮胎动载荷分别降低11.63%、11.42%,在D级路面下轮胎动载荷降低14.12%。台架试验的结果与仿真分析的结果基本一致,表明所设计的自适应内外环控制有效。 展开更多
关键词 振动与波 路面识别 随机森林 XGBoost算法 混合天地棚控制 自适应滑模控制
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陆浑灌区实际蒸散发影响因素分析 被引量:1
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作者 张金萍 李学淳 +2 位作者 李杜白 李玉达 李志伟 《节水灌溉》 北大核心 2024年第3期42-49,共8页
实际蒸散发是水文循环的关键环节,分析灌区实际蒸散发及其影响因素对灌区水资源的高效利用和农业高质量发展具有重要意义。然而,目前蒸散发的影响因素研究在确定主要因素时往往采用解释力较差的传统统计学方法,在相关性分析时忽略了蒸... 实际蒸散发是水文循环的关键环节,分析灌区实际蒸散发及其影响因素对灌区水资源的高效利用和农业高质量发展具有重要意义。然而,目前蒸散发的影响因素研究在确定主要因素时往往采用解释力较差的传统统计学方法,在相关性分析时忽略了蒸散发与其影响因素在空间上的相关性。因此利用改进的随机森林模型确定实际蒸散发的主要影响因素,并通过岭回归模型和地理加权回归模型探究实际蒸散发与其影响因素的时空相关关系。结果表明:(1)在灌溉期,地表净辐射、平均气温、叶面积指数和实际水汽压是实际蒸散发的主要影响因素;在非灌溉期,地表净辐射、平均气温、风速和日照时间是实际蒸散发的主要影响因素。实际蒸散发在一定程度上代表了灌区的作物耗水量。因此,灌区作物耗水在灌溉期和非灌溉期的影响作用有一定的差异。(2)在时间上,风速与实际蒸散发为负相关关系且呈显著负相关(P<0.05),其余影响因素与实际蒸散发均为正相关关系且呈显著正相关(P<0.05);在空间上,除风速与实际蒸散发在大部分区域呈负相关关系,其余影响因素都与实际蒸散发在大部分区域呈正相关关系。因此,除风速外,其余影响因素对灌区作物耗水在大部分区域都为正向促进作用。 展开更多
关键词 实际蒸散发 影响因素 蜻蜓优化算法 随机森林 相关性分析 灌溉期
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基于随机森林算法的重型颅脑损伤患者并发急性胃肠损伤的现状及风险模型构建
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作者 杨晓文 许彬 +2 位作者 吴娟 王希 赵琳 《军事护理》 CSCD 北大核心 2024年第3期70-73,78,共5页
目的探讨重型颅脑损伤患者并发急性胃肠损伤的危险因素,为预防急性胃肠损伤提供借鉴。方法2021年1月至2023年1月,便利抽样法选取某院收治的重型颅脑损伤患者150例为研究对象,建立基于重型颅脑损伤并发急性胃肠损伤的危险因素的随机森林... 目的探讨重型颅脑损伤患者并发急性胃肠损伤的危险因素,为预防急性胃肠损伤提供借鉴。方法2021年1月至2023年1月,便利抽样法选取某院收治的重型颅脑损伤患者150例为研究对象,建立基于重型颅脑损伤并发急性胃肠损伤的危险因素的随机森林算法的预测模型。结果150例重症颅脑损伤患者中,并发急性胃肠损伤患者94例,占62.67%。是否并发急性胃肠道损伤的患者在糖尿病、白蛋白、APACHE-Ⅱ评分、休克指数、液体负平衡、酸中毒、深度镇静、呼吸衰竭方面的差异均有统计学意义(均P<0.05)。构建重型颅脑损伤并发急性胃肠损伤的随机森林模型,树的数量为103时出现的错误率最低;影响重型颅脑损伤并发急性胃肠损伤的因素重要性排序为糖尿病、液体负平衡、急性生理与慢性健康评分、白蛋白、深度镇静及酸中毒;随机森林模型预测重型颅脑损伤并发急性胃肠损伤的受试者工作特征曲线(receiver operating characteristic,ROC)下面积(area under curve,AUC)为0.798,Logistic回归模型的AUC为0.773。结论构建的重型颅脑损伤并发急性胃肠损伤的风险预测模型预测效能较高,临床值得推广应用。 展开更多
关键词 随机森林算法 重型颅脑损伤 急性胃肠损伤 风险模型
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基于Sentinel-2影像的巴尔托洛冰川冰面湖研究
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作者 刘晓 孙永玲 +1 位作者 孙世金 李敏 《测绘通报》 CSCD 北大核心 2024年第3期49-53,80,共6页
冰面湖是冰川的重要组成部分,是冰川消融的指示器,不仅对全球气候变化响应迅速,而且对了解和掌握区域水资源信息意义重大。本文基于Sentinel-2遥感数据,利用随机森林算法,对巴尔托洛冰川冰面湖进行识别提取,并基于提取结果分析研究区冰... 冰面湖是冰川的重要组成部分,是冰川消融的指示器,不仅对全球气候变化响应迅速,而且对了解和掌握区域水资源信息意义重大。本文基于Sentinel-2遥感数据,利用随机森林算法,对巴尔托洛冰川冰面湖进行识别提取,并基于提取结果分析研究区冰面湖的空间分布特征,以及冰面湖面积、数量与冰川高程的关系。本文冰面湖提取的准确率达96.07%,完整率达92.18%,错误率为11.59%;识别出巴尔托洛冰川冰面湖567个,面积为249.46~37134 m^(2);冰面湖多分布在距冰川末端3~26 km处,其中海拔3800~4300 m之间冰面湖数量最多,面积普遍较大,平均面积为1922 m^(2);随着高程的升高,冰面湖的数量和面积逐渐减少,在高程5300 m以上冰面湖数量仅为15个,平均面积为356 m^(2);高程升高导致冰面温度降低,是冰面湖数量和面积骤减的主要原因。 展开更多
关键词 巴尔托洛冰川 冰面湖 Sentinel-2影像 随机森林算法
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街道建成环境对短距离通勤方式选择的影响----以武汉市主城区为例
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作者 贺慧 张庆昊 +2 位作者 郭亮 张彤 荣升 《现代城市研究》 北大核心 2024年第7期17-23,共7页
短距离通勤在交通活动中占据相当的比例,其通勤方式选择存在一定弹性。街道作为承载短距离通勤活动的空间,其建成环境可能对通勤方式选择产生一定影响。文章借助随机森林算法测度街道建成环境对短距离通勤方式选择的影响,识别出建成环... 短距离通勤在交通活动中占据相当的比例,其通勤方式选择存在一定弹性。街道作为承载短距离通勤活动的空间,其建成环境可能对通勤方式选择产生一定影响。文章借助随机森林算法测度街道建成环境对短距离通勤方式选择的影响,识别出建成环境要素的影响梯度及作用曲线,并基于此评估在武汉市主城区内每条街道上,不同短距离通勤方式的选择倾向。结果表明:街道网络特征、断面及景色特征等均对短距离通勤方式选择产生了重要影响;相同街道建成环境对各类通勤方式选择的影响并不一致;在公园绿地附近、住区或商业中心等不同城市区域的街道上,短距离通勤方式的选择倾向存在差异。结论可为绿色出行导向下的街道更新及规划设计提供参考。 展开更多
关键词 街道 建成环境 短距离通勤 通勤方式选择 随机森林算法
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数字乡村建设赋能县域经济高质量发展研究——基于技术进步偏向视角
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作者 王振华 江金启 《经济经纬》 CSSCI 北大核心 2024年第4期29-43,共15页
利用全国1869个县域数据,基于新发展理念构建指标体系,采用随机森林算法测度并描述全国县域高质量发展水平,并进一步从技术进步偏向的视角分析数字乡村建设赋能县域高质量发展的效应和机制。研究发现:第一,中国县域高质量发展水平稳步提... 利用全国1869个县域数据,基于新发展理念构建指标体系,采用随机森林算法测度并描述全国县域高质量发展水平,并进一步从技术进步偏向的视角分析数字乡村建设赋能县域高质量发展的效应和机制。研究发现:第一,中国县域高质量发展水平稳步提高,综合指数均值整体呈现波动上升趋势,且存在着显著的全局空间集聚效应和地域差异,障碍因素诊断发现创新相较于其他四个维度障碍度的比例较大。第二,数字乡村建设能够显著促进中国县域的高质量发展。第三,技术进步偏向在数字乡村建设对中国县域高质量发展的影响中发挥中介作用。具体而言,数字乡村建设能够加快促进中国县域技术进步发生由劳动偏向型向资本偏向型的转变,并进而增加县域创新产出来显著推动中国县域经济高质量发展。因此,应继续强化数字赋能,引导资本更多向县域流动,强化技术进步的资本偏向,以发挥数字乡村建设赋能县域高质量发展的作用。 展开更多
关键词 县域经济高质量发展 数字乡村 技术进步偏向 新发展理念 随机森林算法
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Prostate cancer prediction forest algorithm that takes using the random into account transrectal ultrasound findings, age, and serum levels of prostate-specific antigen 被引量:5
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作者 Li-Hong Xiao Pei-Ran Chen +4 位作者 Zhong-Ping Gou Yong-Zhong Li Mei Li Liang-Cheng Xiang Ping Feng 《Asian Journal of Andrology》 SCIE CAS CSCD 2017年第5期586-590,共5页
The aim of this study is to evaluate the ability of the random forest algorithm that combines data on transrectal ultrasound findings, age, and serum levels of prostate-specific antigen to predict prostate carcinoma. ... The aim of this study is to evaluate the ability of the random forest algorithm that combines data on transrectal ultrasound findings, age, and serum levels of prostate-specific antigen to predict prostate carcinoma. Clinico-demographic data were analyzed for 941 patients with prostate diseases treated at our hospital, including age, serum prostate-specific antigen levels, transrectal ultrasound findings, and pathology diagnosis based on ultrasound-guided needle biopsy of the prostate. These data were compared between patients with and without prostate cancer using the Chi-square test, and then entered into the random forest model to predict diagnosis. Patients with and without prostate cancer differed significantly in age and serum prostate-specific antigen levels (P 〈 0.001), as well as in all transrectal ultrasound characteristics (P 〈 0.05) except uneven echo (P = 0.609). The random forest model based on age, prostate-specific antigen and ultrasound predicted prostate cancer with an accuracy of 83.10%, sensitivity of 65.64%, and specificity of 93.83%. Positive predictive value was 86.72%, and negative predictive value was 81.64%. By integrating age, prostate-specific antigen levels and transrectal ultrasound findings, the random forest algorithm shows better diagnostic performance for prostate cancer than either diagnostic indicator on its own. This algorithm may help improve diagnosis of the disease by identifying patients at high risk for biopsy. 展开更多
关键词 diagnosis prostate cancer prostate-specific antigen random forest algorithm transrectal ultrasound characteristics
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