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Managing cotton canopy architecture for machine picking cotton via high plant density and plant growth retardants 被引量:1
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作者 LAKSHMANAN Sankar SOMASUNDARAM Selvaraj +4 位作者 SHRI RANGASAMI Silambiah ANANTHARAJU Pokkharu VIJAYALAKSHMI Dhashnamurthi RAGAVAN Thiruvengadam DHAMODHARAN Paramasivam 《Journal of Cotton Research》 2025年第1期102-114,共13页
Machine picking in cotton is an emerging practice in India,to solve the problems of labour shortages and production costs increasing.Cotton production has been declining in recent years;however,the high density planti... Machine picking in cotton is an emerging practice in India,to solve the problems of labour shortages and production costs increasing.Cotton production has been declining in recent years;however,the high density planting system(HDPS)offers a viable method to enhance productivity by increasing plant populations per unit area,optimizing resource utilization,and facilitating machine picking.Cotton is an indeterminate plant that produce excessive vegeta-tive growth in favorable soil fertility and moisture conditions,which posing challenges for efficient machine picking.To address this issue,the application of plant growth retardants(PGRs)is essential for controlling canopy architecture.PGRs reduce internode elongation,promote regulated branching,and increase plant compactness,making cotton plants better suited for machine picking.PGRs application also optimizes photosynthates distribution between veg-etative and reproductive growth,resulting in higher yields and improved fibre quality.The integration of HDPS and PGRs applications results in an optimal plant architecture for improving machine picking efficiency.However,the success of this integration is determined by some factors,including cotton variety,environmental conditions,and geographical variations.These approaches not only address yield stagnation and labour shortages but also help to establish more effective and sustainable cotton farming practices,resulting in higher cotton productivity. 展开更多
关键词 COTTON High density planting system Plant growth retardant Canopy management Defoliators machine picking Yield improvement
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Graded density impactor design via machine learning and numerical simulation:Achieve controllable stress and strain rate 被引量:1
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作者 Yahui Huang Ruizhi Zhang +6 位作者 Shuaixiong Liu Jian Peng Yong Liu Han Chen Jian Zhang Guoqiang Luo Qiang Shen 《Defence Technology(防务技术)》 2025年第9期262-273,共12页
The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to ... The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to achieving controllable stress-strain rate loading.In this study,we have,for the first time,combined one-dimensional fluid computational software with machine learning methods.We first elucidated the mechanisms by which GDI structures control stress and strain rates.Subsequently,we constructed a machine learning model to create a structure-property response surface.The results show that altering the loading velocity and interlayer thickness has a pronounced regulatory effect on stress and strain rates.In contrast,the impedance distribution index and target thickness have less significant effects on stress regulation,although there is a matching relationship between target thickness and interlayer thickness.Compared with traditional design methods,the machine learning approach offers a10^(4)—10^(5)times increase in efficiency and the potential to achieve a global optimum,holding promise for guiding the design of GDI. 展开更多
关键词 machine learning Numerical simulation Graded density impactor Controllable stress-strain rate loading Response surface methodology
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High-precision quantitative analysis of 3-nitro-1,2,4-triazol-5-one(NTO)concentration based on ATR-FTIR spectroscopy and machine learning
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作者 Zhe Zhang Zhuowei Sun +4 位作者 Haoming Zou Xijuan Lv Ziyang Guo Shuai Zhao Qinghai Shu 《Defence Technology(防务技术)》 2025年第10期131-141,共11页
3-Nitro-1,2,4-triazol-5-one(NTO)is a typical high-energy,low-sensitivity explosive,and accurate concentration monitoring is critical for crystallization process control.In this study,a high-precision quantitative anal... 3-Nitro-1,2,4-triazol-5-one(NTO)is a typical high-energy,low-sensitivity explosive,and accurate concentration monitoring is critical for crystallization process control.In this study,a high-precision quantitative analytical model for NTO concentration in ethanol solutions was developed by integrating real-time ATR-FTIR spectroscopy with chemometric and machine learning techniques.Dynamic spectral data were obtained by designing multi-concentration gradient heating-cooling cycle experiments,abnormal samples were eliminated using the isolation forest algorithm,and the effects of various preprocessing methods on model performance were systematically evaluated.The results show that partial least squares regression(PLSR)exhibits superior generalization ability compared to other models.Vibrational bands corresponding to C=O and–NO_(2)were identified as key predictors for concentration estimation.This work provides an efficient and reliable solution for real-time concentration monitoring during NTO crystallization and holds significant potential for process analytical applications in energetic material manufacturing. 展开更多
关键词 ATR-FTIR spectroscopy machine learning Quantitative analysis
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Machine learning improve the discrimination of raw cotton from different countries
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作者 WANG Tian XU Shuangjiao +4 位作者 WEI Jingyan WANG Ming DU Weidong TIAN Xinquan MA Lei 《Journal of Cotton Research》 2025年第3期444-456,共13页
Background The geo-traceability of cotton is crucial for ensuring the quality and integrity of cotton brands. However, effective methods for achieving this traceability are currently lacking. This study investigates t... Background The geo-traceability of cotton is crucial for ensuring the quality and integrity of cotton brands. However, effective methods for achieving this traceability are currently lacking. This study investigates the potential of explainable machine learning for the geo-traceability of raw cotton.Results The findings indicate that principal component analysis(PCA) exhibits limited effectiveness in tracing cotton origins. In contrast, partial least squares discriminant analysis(PLS-DA) demonstrates superior classification performance, identifying seven discriminating variables: Na, Mn, Ba, Rb, Al, As, and Pb. The use of decision tree(DT), support vector machine(SVM), and random forest(RF) models for origin discrimination yielded accuracies of 90%, 87%, and 97%, respectively. Notably, the light gradient boosting machine(Light GBM) model achieved perfect performance metrics, with accuracy, precision, and recall rate all reaching 100% on the test set. The output of the Light GBM model was further evaluated using the SHapley Additive ex Planation(SHAP) technique, which highlighted differences in the elemental composition of raw cotton from various countries. Specifically, the elements Pb, Ni, Na, Al, As, Ba, and Rb significantly influenced the model's predictions.Conclusion These findings suggest that explainable machine learning techniques can provide insights into the complex relationships between geographic information and raw cotton. Consequently, these methodologies enhances the precision and reliability of geographic traceability for raw cotton. 展开更多
关键词 Raw cotton Mineral elements machine learning Shapley value
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Machine learning models for optimization, validation, and prediction of light emitting diodes with kinetin based basal medium for in vitro regeneration of upland cotton (Gossypium hirsutum L.)
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作者 ÖZKAT Gözde Yalçın AASIM Muhammad +2 位作者 BAKHSH Allah ALI Seyid Amjad ÖZCAN Sebahattin 《Journal of Cotton Research》 2025年第2期228-241,共14页
Background Plant tissue culture has emerged as a tool for improving cotton propagation and genetics,but recalcitrance nature of cotton makes it difficult to develop in vitro regeneration.Cotton’s recalcitrance is inf... Background Plant tissue culture has emerged as a tool for improving cotton propagation and genetics,but recalcitrance nature of cotton makes it difficult to develop in vitro regeneration.Cotton’s recalcitrance is influenced by genotype,explant type,and environmental conditions.To overcome these issues,this study uses different machine learning-based predictive models by employing multiple input factors.Cotyledonary node explants of two commercial cotton cultivars(STN-468 and GSN-12)were isolated from 7–8 days old seedlings,preconditioned with 5,10,and 20 mg·L^(-1) kinetin(KIN)for 10 days.Thereafter,explants were postconditioned on full Murashige and Skoog(MS),1/2MS,1/4MS,and full MS+0.05 mg·L^(-1) KIN,cultured in growth room enlightened with red and blue light-emitting diodes(LED)combination.Statistical analysis(analysis of variance,regression analysis)was employed to assess the impact of different treatments on shoot regeneration,with artificial intelligence(AI)models used for confirming the findings.Results GSN-12 exhibited superior shoot regeneration potential compared with STN-468,with an average of 4.99 shoots per explant versus 3.97.Optimal results were achieved with 5 mg·L^(-1) KIN preconditioning,1/4MS postconditioning,and 80%red LED,with maximum of 7.75 shoot count for GSN-12 under these conditions;while STN-468 reached 6.00 shoots under the conditions of 10 mg·L^(-1) KIN preconditioning,MS with 0.05 mg·L^(-1) KIN(postconditioning)and 75.0%red LED.Rooting was successfully achieved with naphthalene acetic acid and activated charcoal.Additionally,three different powerful AI-based models,namely,extreme gradient boost(XGBoost),random forest(RF),and the artificial neural network-based multilayer perceptron(MLP)regression models validated the findings.Conclusion GSN-12 outperformed STN-468 with optimal results from 5 mg·L^(-1) KIN+1/4MS+80%red LED.Application of machine learning-based prediction models to optimize cotton tissue culture protocols for shoot regeneration is helpful to improve cotton regeneration efficiency. 展开更多
关键词 machine learning COTTON In vitro regeneration Light emitting diodes OPTIMIZATION KINETIN
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Accurate prediction of blast-induced ground vibration intensity using optimized machine learning models
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作者 Lihua Chen Yewuhalashet Fissha +3 位作者 Mahdi Hasanipanah Refka Ghodhbani Hesam Dehghani Jitendra Khatti 《Defence Technology(防务技术)》 2025年第10期32-46,共15页
Blast-induced ground vibration,quantified by peak particle velocity(PPV),is a crucial factor in mitigating environmental and structural risks in mining and geotechnical engineering.Accurate PPV prediction facilitates ... Blast-induced ground vibration,quantified by peak particle velocity(PPV),is a crucial factor in mitigating environmental and structural risks in mining and geotechnical engineering.Accurate PPV prediction facilitates safer and more sustainable blasting operations by minimizing adverse impacts and ensuring regulatory compliance.This study presents an advanced predictive framework integrating Cat Boost(CB)with nature-inspired optimization algorithms,including the Bat Algorithm(BAT),Sparrow Search Algorithm(SSA),Butterfly Optimization Algorithm(BOA),and Grasshopper Optimization Algorithm(GOA).A comprehensive dataset from the Sarcheshmeh Copper Mine in Iran was utilized to develop and evaluate these models using key performance metrics such as the Index of Agreement(IoA),Nash-Sutcliffe Efficiency(NSE),and the coefficient of determination(R^(2)).The hybrid CB-BOA model outperformed other approaches,achieving the highest accuracy(R^(2)=0.989)and the lowest prediction errors.SHAP analysis identified Distance(Di)as the most influential variable affecting PPV,while uncertainty analysis confirmed CB-BOA as the most reliable model,featuring the narrowest prediction interval.These findings highlight the effectiveness of hybrid machine learning models in refining PPV predictions,contributing to improved blast design strategies,enhanced structural safety,and reduced environmental impacts in mining and geotechnical engineering. 展开更多
关键词 Ground vibrations Peak particle velocity machine learning CatBoost Nature-inspired optimization Blasting safety
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Machine learning model comparison and ensemble for predicting different morphological fractions of heavy metal elements in tailings and mine waste
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作者 FENG Yu-xin HU Tao +4 位作者 ZHOU Na-na ZHOU Min BARKHORDARI Mohammad Sadegh LI Ke-chao QI Chong-chong 《Journal of Central South University》 2025年第9期3557-3573,共17页
Driven by rapid technological advancements and economic growth,mineral extraction and metal refining have increased dramatically,generating huge volumes of tailings and mine waste(TMWs).Investigating the morphological... Driven by rapid technological advancements and economic growth,mineral extraction and metal refining have increased dramatically,generating huge volumes of tailings and mine waste(TMWs).Investigating the morphological fractions of heavy metals and metalloids(HMMs)in TMWs is key to evaluating their leaching potential into the environment;however,traditional experiments are time-consuming and labor-intensive.In this study,10 machine learning(ML)algorithms were used and compared for rapidly predicting the morphological fractions of HMMs in TMWs.A dataset comprising 2376 data points was used,with mineral composition,elemental properties,and total concentration used as inputs and concentration of morphological fraction used as output.After grid search optimization,the extra tree model performed the best,achieving coefficient of determination(R2)of 0.946 and 0.942 on the validation and test sets,respectively.Electronegativity was found to have the greatest impact on the morphological fraction.The models’performance was enhanced by applying an ensemble method to the top three optimal ML models,including gradient boosting decision tree,extra trees and categorical boosting.Overall,the proposed framework can accurately predict the concentrations of different morphological fractions of HMMs in TMWs.This approach can minimize detection time,aid in the safe management and recovery of TMWs. 展开更多
关键词 tailings and mine waste morphological fractions model comparison machine learning model ensemble
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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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Damage prediction of rear plate in Whipple shields based on machine learning method
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作者 Chenyang Wu Xiangbiao Liao +1 位作者 Lvtan Chen Xiaowei Chen 《Defence Technology(防务技术)》 2025年第8期52-68,共17页
A typical Whipple shield consists of double-layered plates with a certain gap.The space debris impacts the outer plate and is broken into a debris cloud(shattered,molten,vaporized)with dispersed energy and momentum,wh... A typical Whipple shield consists of double-layered plates with a certain gap.The space debris impacts the outer plate and is broken into a debris cloud(shattered,molten,vaporized)with dispersed energy and momentum,which reduces the risk of penetrating the bulkhead.In the realm of hypervelocity impact,strain rate(>10^(5)s^(-1))effects are negligible,and fluid dynamics is employed to describe the impact process.Efficient numerical tools for precisely predicting the damage degree can greatly accelerate the design and optimization of advanced protective structures.Current hypervelocity impact research primarily focuses on the interaction between projectile and front plate and the movement of debris cloud.However,the damage mechanism of debris cloud impacts on rear plates-the critical threat component-remains underexplored owing to complex multi-physics processes and prohibitive computational costs.Existing approaches,ranging from semi-empirical equations to a machine learningbased ballistic limit prediction method,are constrained to binary penetration classification.Alternatively,the uneven data from experiments and simulations caused these methods to be ineffective when the projectile has irregular shapes and complicate flight attitude.Therefore,it is urgent to develop a new damage prediction method for predicting the rear plate damage,which can help to gain a deeper understanding of the damage mechanism.In this study,a machine learning(ML)method is developed to predict the damage distribution in the rear plate.Based on the unit velocity space,the discretized information of debris cloud and rear plate damage from rare simulation cases is used as input data for training the ML models,while the generalization ability for damage distribution prediction is tested by other simulation cases with different attack angles.The results demonstrate that the training and prediction accuracies using the Random Forest(RF)algorithm significantly surpass those using Artificial Neural Networks(ANNs)and Support Vector Machine(SVM).The RF-based model effectively identifies damage features in sparsely distributed debris cloud and cumulative effect.This study establishes an expandable new dataset that accommodates additional parameters to improve the prediction accuracy.Results demonstrate the model's ability to overcome data imbalance limitations through debris cloud features,enabling rapid and accurate rear plate damage prediction across wider scenarios with minimal data requirements. 展开更多
关键词 Damage prediction of rear plate Cumulative effect of debris cloud Whipple shield machine learning Random forest
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基于改进MFCC-OCSVM和贝叶斯优化BiGRU的GIS异常工况声纹识别算法 被引量:3
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作者 庄小亮 李乾坤 +3 位作者 刘紫罡 张禄亮 季天瑶 张长虹 《南方电网技术》 北大核心 2025年第1期30-40,共11页
为了准确识别气体绝缘开关柜(gas insulated switchgear,GIS)设备的异常工况,提出了一种基于加权梅尔频率谱系数单类支持向量机(Mel frequency cestrum coefficient-one class support vector machine,MFCC-OCSVM)和贝叶斯优化的门控循... 为了准确识别气体绝缘开关柜(gas insulated switchgear,GIS)设备的异常工况,提出了一种基于加权梅尔频率谱系数单类支持向量机(Mel frequency cestrum coefficient-one class support vector machine,MFCC-OCSVM)和贝叶斯优化的门控循环单元(bidirectional gate recurrent unit,BiGRU)声纹识别算法。首先,利用基于F统计量的MFCC对声纹数据进行加权特征提取,突出重要特征并减弱噪声的影响,然后利用OCSVM对加权后的特征进行异常检测并去除异常值,提高数据质量。为解决样本不平衡问题,采用合成少数类过采样技术(synthetic minority over-sampling technique,SMOTE)进行声纹样本的均衡。最后,应用基于贝叶斯优化的BiGRU模型进行声纹识别。以某气体绝缘全封闭组合电器(gas insulated switchgear,GIS)为例,采集了20类不同工况下操纵机构的声音样本,与多种经典分类模型进行对比。结果显示,所提算法取得的最高平均识别准确率达到了92.8%,相比于自适应增强、朴素贝叶斯和线性判别分析算法分别提升了30.1%、14.7%和11.5%。通过消融实验进一步评估和验证了所提算法各个流程对声纹识别的实际效果和性能影响,研究成果可为GIS设备异常工况的声纹识别提供高效技术路线。 展开更多
关键词 GIS设备 梅尔频谱倒谱系数 单类支持向量机 双向门控循环单元 声纹识别 贝叶斯优化
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Machine learning for predicting the outcome of terminal ballistics events 被引量:4
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作者 Shannon Ryan Neeraj Mohan Sushma +4 位作者 Arun Kumar AV Julian Berk Tahrima Hashem Santu Rana Svetha Venkatesh 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期14-26,共13页
Machine learning(ML) is well suited for the prediction of high-complexity,high-dimensional problems such as those encountered in terminal ballistics.We evaluate the performance of four popular ML-based regression mode... Machine learning(ML) is well suited for the prediction of high-complexity,high-dimensional problems such as those encountered in terminal ballistics.We evaluate the performance of four popular ML-based regression models,extreme gradient boosting(XGBoost),artificial neural network(ANN),support vector regression(SVR),and Gaussian process regression(GP),on two common terminal ballistics’ problems:(a)predicting the V50ballistic limit of monolithic metallic armour impacted by small and medium calibre projectiles and fragments,and(b) predicting the depth to which a projectile will penetrate a target of semi-infinite thickness.To achieve this we utilise two datasets,each consisting of approximately 1000samples,collated from public release sources.We demonstrate that all four model types provide similarly excellent agreement when interpolating within the training data and diverge when extrapolating outside this range.Although extrapolation is not advisable for ML-based regression models,for applications such as lethality/survivability analysis,such capability is required.To circumvent this,we implement expert knowledge and physics-based models via enforced monotonicity,as a Gaussian prior mean,and through a modified loss function.The physics-informed models demonstrate improved performance over both classical physics-based models and the basic ML regression models,providing an ability to accurately fit experimental data when it is available and then revert to the physics-based model when not.The resulting models demonstrate high levels of predictive accuracy over a very wide range of projectile types,target materials and thicknesses,and impact conditions significantly more diverse than that achievable from any existing analytical approach.Compared with numerical analysis tools such as finite element solvers the ML models run orders of magnitude faster.We provide some general guidelines throughout for the development,application,and reporting of ML models in terminal ballistics problems. 展开更多
关键词 machine learning Artificial intelligence Physics-informed machine learning Terminal ballistics Armour
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Physics-informed machine learning model for prediction of ground reflected wave peak overpressure
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作者 Haoyu Zhang Yuxin Xu +1 位作者 Lihan Xiao Canjie Zhen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第11期119-133,共15页
The accurate prediction of peak overpressure of explosion shockwaves is significant in fields such as explosion hazard assessment and structural protection, where explosion shockwaves serve as typical destructive elem... The accurate prediction of peak overpressure of explosion shockwaves is significant in fields such as explosion hazard assessment and structural protection, where explosion shockwaves serve as typical destructive elements. Aiming at the problem of insufficient accuracy of the existing physical models for predicting the peak overpressure of ground reflected waves, two physics-informed machine learning models are constructed. The results demonstrate that the machine learning models, which incorporate physical information by predicting the deviation between the physical model and actual values and adding a physical loss term in the loss function, can accurately predict both the training and out-oftraining dataset. Compared to existing physical models, the average relative error in the predicted training domain is reduced from 17.459%-48.588% to 2%, and the proportion of average relative error less than 20% increased from 0% to 59.4% to more than 99%. In addition, the relative average error outside the prediction training set range is reduced from 14.496%-29.389% to 5%, and the proportion of relative average error less than 20% increased from 0% to 71.39% to more than 99%. The inclusion of a physical loss term enforcing monotonicity in the loss function effectively improves the extrapolation performance of machine learning. The findings of this study provide valuable reference for explosion hazard assessment and anti-explosion structural design in various fields. 展开更多
关键词 Blast shock wave Peak overpressure machine learning Physics-informed machine learning
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矿井通风系统智能故障诊断MC-OCSVM模型 被引量:10
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作者 沈志远 杨镇隆 +1 位作者 焦莉 赵丹 《安全与环境学报》 CAS CSCD 北大核心 2024年第8期3126-3132,共7页
为解决矿井通风系统故障分支判识不准确的问题,引入单分类算法,构建了多个单分类支持向量机(One-Class Support Vector Machines, OCSVM)集成的通风系统故障诊断模型。模型采用统一超参数并设计了尺度统一公式以实现多个输出尺度的统一... 为解决矿井通风系统故障分支判识不准确的问题,引入单分类算法,构建了多个单分类支持向量机(One-Class Support Vector Machines, OCSVM)集成的通风系统故障诊断模型。模型采用统一超参数并设计了尺度统一公式以实现多个输出尺度的统一,将通风系统故障诊断问题转变为最大决策距离问题,建立仅需正常样本参与训练的通风系统故障诊断半监督学习模型,实现对矿井监测风速数据的有效利用。进行了KEEL公开数据集和东山煤矿生产矿井实例试验,结果表明,单分类集成模型能够解决多分类问题,与其他单分类集成模型相比,单分类支持向量机集成(Multi-Class One-Class SVM,MC-OCSVM)模型具有最佳的泛化性,所提模型能够快速准确地识别通风系统故障分支,故障诊断准确率达93.2%,单次故障诊断时间为1.2 s,具有较强的鲁棒性。研究工作是实现矿井通风智能化的基础,为通风系统故障诊断提供技术支撑。 展开更多
关键词 安全工程 矿井通风 智能算法 故障诊断 单分类集成 单分类支持向量机(Ocsvm)
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Machine learning molecular dynamics simulations of liquid methanol
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作者 Jie Qian Junfan Xia Bin Jiang 《中国科学技术大学学报》 CAS CSCD 北大核心 2024年第6期12-21,I0009,I0010,共12页
As the simplest hydrogen-bonded alcohol,liquid methanol has attracted intensive experimental and theoretical interest.However,theoretical investigations on this system have primarily relied on empirical intermolecular... As the simplest hydrogen-bonded alcohol,liquid methanol has attracted intensive experimental and theoretical interest.However,theoretical investigations on this system have primarily relied on empirical intermolecular force fields or ab initio molecular dynamics with semilocal density functionals.Inspired by recent studies on bulk water using increasingly accurate machine learning force fields,we report a new machine learning force field for liquid methanol with a hybrid functional revPBE0 plus dispersion correction.Molecular dynamics simulations on this machine learning force field are orders of magnitude faster than ab initio molecular dynamics simulations,yielding the radial distribution functions,selfdiffusion coefficients,and hydrogen bond network properties with very small statistical errors.The resulting structural and dynamical properties are compared well with the experimental data,demonstrating the superior accuracy of this machine learning force field.This work represents a successful step toward a first-principles description of this benchmark system and showcases the general applicability of the machine learning force field in studying liquid systems. 展开更多
关键词 liquid methanol molecular dynamics machine learning hydrogen bond force field
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An empirical study on the effect of user engagement on personalized free-content promotion based on a causal machine learning model
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作者 Shuang Wang Hanbing Xue Lizheng Wang 《中国科学技术大学学报》 CSCD 北大核心 2024年第10期51-62,I0007,共13页
Many digital platforms have employed free-content promotion strategies to deal with the high uncertainty levels regarding digital content products.However,the diversity of digital content products and user heterogenei... Many digital platforms have employed free-content promotion strategies to deal with the high uncertainty levels regarding digital content products.However,the diversity of digital content products and user heterogeneity in content preference may blur the impact of platform promotions across users and products.Therefore,free-content promotion strategies should be adapted to allocate marketing resources optimally and increase revenue.This study develops personal-ized free-content promotion strategies based on individual-level heterogeneous treatment effects and explores the causes of their heterogeneity,focusing on the moderating effect of user engagement-related variables.To this end,we utilize ran-dom field experimental data provided by a top Chinese e-book platform.We employ a framework that combines machine learning with econometric causal inference methods to estimate individual treatment effects and analyze their potential mechanisms.The analysis shows that,on average,free-content promotions lead to a significant increase in consumer pay-ments.However,the higher the level of user engagement,the lower the payment lift caused by promotions,as more-engaged users are more strongly affected by the cannibalization effect of free-content promotion.This study introduces a novel causal research design to help platforms improve their marketing strategies. 展开更多
关键词 free-content promotion user engagement random experiment causal machine learning individual-level treat-ment effect
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Pose prediction based on dynamic modeling and virtual prototype simulation of shield tunnelling machine
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作者 JIN Da-long WANG Xu-yang +2 位作者 YUAN Da-jun LI Xiu-dong DU Chang-yan 《Journal of Central South University》 CSCD 2024年第11期3854-3867,共14页
Compared with traditional feedback control,predictive control can eliminate the lag of pose control and avoid the snakelike motion of shield machines.Therefore,a shield pose prediction model was proposed based on dyna... Compared with traditional feedback control,predictive control can eliminate the lag of pose control and avoid the snakelike motion of shield machines.Therefore,a shield pose prediction model was proposed based on dynamic modeling.Firstly,the dynamic equations of shield thrust system were established to clarify the relationship between force and movement of shield machine.Secondly,an analytical model was proposed to predict future multistep pose of the shield machine.Finally,a virtual prototype model was developed to simulate the dynamic behavior of the shield machine and validate the accuracy of the proposed pose prediction method.Results reveal that the model proposed can predict the shield pose with high accuracy,which can provide a decision basis whether for manual or automatic control of shield pose. 展开更多
关键词 shield machine motion trajectory dynamic modeling virtual prototype pose prediction
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A physics-informed machine learning solution for landslide susceptibility mapping based on three-dimensional slope stability evaluation
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作者 WANG Yun-hao WANG Lu-qi +4 位作者 ZHANG Wen-gang LIU Song-lin SUN Wei-xin HONG Li ZHU Zheng-wei 《Journal of Central South University》 CSCD 2024年第11期3838-3853,共16页
Landslide susceptibility mapping is a crucial tool for disaster prevention and management.The performance of conventional data-driven model is greatly influenced by the quality of the samples data.The random selection... Landslide susceptibility mapping is a crucial tool for disaster prevention and management.The performance of conventional data-driven model is greatly influenced by the quality of the samples data.The random selection of negative samples results in the lack of interpretability throughout the assessment process.To address this limitation and construct a high-quality negative samples database,this study introduces a physics-informed machine learning approach,combining the random forest model with Scoops 3D,to optimize the negative samples selection strategy and assess the landslide susceptibility of the study area.The Scoops 3D is employed to determine the factor of safety value leveraging Bishop’s simplified method.Instead of conventional random selection,negative samples are extracted from the areas with a high factor of safety value.Subsequently,the results of conventional random forest model and physics-informed data-driven model are analyzed and discussed,focusing on model performance and prediction uncertainty.In comparison to conventional methods,the physics-informed model,set with a safety area threshold of 3,demonstrates a noteworthy improvement in the mean AUC value by 36.7%,coupled with a reduced prediction uncertainty.It is evident that the determination of the safety area threshold exerts an impact on both prediction uncertainty and model performance. 展开更多
关键词 machine learning physics-informed model negative samples selection INTERPRETABILITY landslide susceptibility mapping
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高光谱预处理方法与多模型在分类判别中的对比研究 被引量:2
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作者 居雷 于洁 +4 位作者 吴炎淼 李丽 卢天 丁亚萍 束茹欣 《光谱学与光谱分析》 SCIE EI CAS 北大核心 2025年第1期125-132,共8页
高光谱技术能够快速、无损地获取丰富的信息,在植物研究和监测中已成为一种广泛应用的工具。茄科植物作为一种重要的经济农作物,与高光谱技术结合进行研究具有巨大的应用潜力。本研究采用高光谱技术对茄科植物的初烤后不同部位叶片进行... 高光谱技术能够快速、无损地获取丰富的信息,在植物研究和监测中已成为一种广泛应用的工具。茄科植物作为一种重要的经济农作物,与高光谱技术结合进行研究具有巨大的应用潜力。本研究采用高光谱技术对茄科植物的初烤后不同部位叶片进行分类研究。采用Field Spec 3光谱辐射仪对293份不同部位的茄科植物粉末样本进行高光谱采样,采用S-G平滑以及一阶导数和二阶导数的方法对数据进行预处理,用于信息增强和去除噪声,并通过偏最小二乘法对数据进行降维,以减少冗余特征。基于降维数据,采样支持向量机、逻辑回归、K近邻、决策树、随机森林和梯度提升决策树这六种机器学习算法建立分类模型。结果显示,在分类任务中,经过一阶导数处理后,支持向量机模型最佳,在训练集和测试集上分别实现了100.0%和84.7%的准确率。经网格参数优化后确定最优参数为:最大深度不限制,最小样本分割数为4,估计器数量为200。参数优化后五折交叉验证准确率为88.1%,训练集准确率为100%,测试集准确率为86.4%。研究结果表明,预处理方法结合降维方法能够增强数据信息使得分类模型能够更好地捕捉茄科植物样本的特征。该研究对于快速、准确、无损地区分茄科植物的部位具有重要意义。 展开更多
关键词 高光谱 部位分类 机器学习
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面向智能时代的教育系统性变革:数字化赋能教育综合改革 被引量:17
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作者 黄荣怀 刘嘉豪 +2 位作者 潘静文 刘梦彧 张国良 《电化教育研究》 北大核心 2025年第4期5-12,共8页
当前,正处于技术驱动教育系统性变革的关键窗口期。面对智能技术迭代加速及其对教育系统的全方位渗透,文章提出以数字化赋能教育综合改革,加速教育系统性变革的行动框架。具体包括:(1)前瞻性教育规划作为实践指引,综合考量未来可能出现... 当前,正处于技术驱动教育系统性变革的关键窗口期。面对智能技术迭代加速及其对教育系统的全方位渗透,文章提出以数字化赋能教育综合改革,加速教育系统性变革的行动框架。具体包括:(1)前瞻性教育规划作为实践指引,综合考量未来可能出现的新技术、新挑战和社会需求;(2)人机协同教学的多元实践,包括构建支持服务环境、开展证据导向的教学实践、完善教育伦理保障体系等;(3)场景驱动的教育变革,有赖于应用场景设计、改革需求洞悉、技术环境适配等基本环节,并以证据表征与夯实为保障,通过场景的迭代优化持续推动教育创新;(4)构建证据链有助于形成教育综合改革的闭环验证,需注重数字思维、数字化领导力、循证手段,并利用人机协同方式监测教育综合改革成效。在人机价值对齐的贯穿下,前瞻性规划、人机协同教学、变革场景演化和证据链构建等多维协同,确保教育系统在变革过程中始终与人类价值观保持一致,共同推动教育生态向个性化、情境化和数据驱动的方向演进,开启智能时代教育的新篇章。 展开更多
关键词 教育综合改革 教育数字化 教育系统性变革 人机价值对齐 人机协同 场景 证据链
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基于机器视觉的海鲜花螺分类研究 被引量:1
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作者 陈林涛 陈睿 +2 位作者 蓝莹 梁国健 牟向伟 《水生生物学报》 北大核心 2025年第2期138-145,共8页
针对目前人工分选海鲜花螺劳动强度大、人工成本高的问题,研究提出一种DPO-SVM海鲜花螺公母分类模型。通过灰度共生矩阵分析提取海鲜花螺外壳间隔纹理特征量,采用SVM作为公母分类模型基体,对不同纹理特征量组合进行分类效果对比,得出使... 针对目前人工分选海鲜花螺劳动强度大、人工成本高的问题,研究提出一种DPO-SVM海鲜花螺公母分类模型。通过灰度共生矩阵分析提取海鲜花螺外壳间隔纹理特征量,采用SVM作为公母分类模型基体,对不同纹理特征量组合进行分类效果对比,得出使用能量、熵、对比度3种特征量分类效果最好的结论。针对SVM优化问题,以PSO和WOA算法为基础提出DPO算法对SVM的重要参数c、g进行优化;对DPO-SVM性能进行测试,将测试结果与SVM、PSO-SVM、WOA-SVM测试结果对比。相比于其他3种SVM模型,DPOSVM分类准确率大幅度提升,相比于SVM,分类总准确率由85%上升至100%,上升了15%;DPO算法提高了单种群优化算法的寻优性能,相比于PSO算法,DPO算法将最佳适应度从95.26提升至98.68,提升幅度为3.47%。此外,达到最佳适应度的迭代次数由14次减少至6次,下降57.14%,显著优化了收敛速度。研究结果可为自动分拣装置中海鲜花螺公母分类提供技术参考。 展开更多
关键词 机器视觉 花螺分选 外壳 纹理特征 支持向量机 算法
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