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Disease Burden and Trends of COPD in the Asia-Pacific Region(1990-2019)and Predictions to 2034 被引量:1
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作者 Jing Ma Hong Mi 《Biomedical and Environmental Sciences》 2025年第5期557-570,共14页
Objective The Asia-Pacific region has a high chronic obstructive pulmonary disease(COPD)burden,but studies on its trends are limited.Using the Global Burden of Disease(GBD)2019 data,we analyzed COPD trends in 36 count... Objective The Asia-Pacific region has a high chronic obstructive pulmonary disease(COPD)burden,but studies on its trends are limited.Using the Global Burden of Disease(GBD)2019 data,we analyzed COPD trends in 36 countries and territories from 1990 to 2019 and predicted future incidence trends through 2034.Methods COPD data by age and sex from the GBD 2019 database were analyzed for incidence,prevalence,mortality,and disability-adjusted life years(DALY)rates from 1990 to 2019.Joinpoint regression identified significant annual trends,and age-standardized incidence rates were predicted through 2034 using age-period-cohort models.Results The incidence,prevalence,mortality,and disease burden of COPD have been decreasing,and the incidence rates will continue to decrease or remain stable until 2034 in most selected countries and territories,except for a few Southeastern Asian countries.The Lao People’s Democratic Republic and Vietnam are projected to experience an increase in COPD incidence from 165.3 per 100,000 in 2019 to 177 per 100,000 in 2034 and from 179.9 per 100,000 in 2019 to 192.5 per 100,000 in 2034,respectively.Older males had a higher incidence than any other sex or age group.The sex gap in incidence rates continues to widen,though it is smaller and less significant in the younger age group than in those in the older one.Conclusion COPD rates are expected to decline until 2034 but remain a health risk,especially in countries with rising rates.Urgent action on tobacco control,air pollution,and public education is needed. 展开更多
关键词 COPD ASIA-PACIFIC INCIDENCE Disease burden TRENDS Prediction
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Spatial Random Effects Improve the Predictions of Multispecies Distribution in a Marine Fish Assemblage
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作者 XU Tianheng ZHANG Chongliang +3 位作者 XU Binduo XUE Ying JI Yupeng REN Yiping 《Journal of Ocean University of China》 2025年第2期471-482,共12页
Species distribution patterns is one of the important topics in ecology and biological conservation.Although species distribution models have been intensively used in the research,the effects of spatial associations a... Species distribution patterns is one of the important topics in ecology and biological conservation.Although species distribution models have been intensively used in the research,the effects of spatial associations and spatial dependence have been rarely taken into account in the modeling processes.Recently,Joint Species Distribution Models(JSDMs)offer the opportunity to consider both environmental factors and interspecific relationships as well as the role of spatial structures.This study uses the HMSC(Hierarchical Modelling of Species Communities)framework to model the multispecies distribution of a marine fish assemblage,in which spatial associations and spatial dependence is deliberately accounted for.Three HMSC models were implemented with different structures of random effects to address the existence of spatial associations and spatial dependence,and the predictive performances at different levels of sample sizes were analyzed in the assessment.The results showed that the models with random effects could account for a larger proportion of explainable variance(32.8%),and particularly the spatial random effect model provided the best predictive performances(R_(mean)^(2)=0.31),indicating that spatial random effects could substantially influence the results of the joint species distribution.Increasing sample size had a strong effect(R_(mean)^(2)=0.24-0.31)on the predictive accuracy of the spatially-structured model than on the other models,suggesting that optimal model selection should be dependent on sample size.This study highlights the importance of incorporating spatial random effects for JSDM predictions and suggests that the choice of model structures should consider the data quality across species. 展开更多
关键词 HMSC spatial autocorrelation JSDM sample size PREDICTABILITY
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Analysis of the Disease Burden of Knee Osteoarthritis in China from 1990 to 2021, Attributable Risk Factors, and Predictions for 2035
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作者 Weigang Liu Qian Wu Heqing Tang 《Journal of Clinical and Nursing Research》 2025年第9期360-369,共10页
Objective:Knee osteoarthritis is one of the important causes of disability worldwide.This study aims to analyze the disease burden of knee osteoarthritis,attributable risk factors among Chinese residents from 1990 to ... Objective:Knee osteoarthritis is one of the important causes of disability worldwide.This study aims to analyze the disease burden of knee osteoarthritis,attributable risk factors among Chinese residents from 1990 to 2021,and predict the disease burden trend for 2035.Methods:Data related to knee osteoarthritis in China from 1990 to 2021,including the number of incident cases,incidence rate,number of prevalent cases,prevalence rate,and years lived with disability(YLDs),were collected from the Global Burden of Disease Study(GBD2021)database.Joinpoint regression analysis was used to assess time trends,and the Bayesian-Age-Period-Cohort(BAPC)regression model was employed for future predictions.Results:From 1990 to 2021,the number of incident cases of knee osteoarthritis among Chinese residents increased from 3.65 million to 8.51 million,a rise of 133.16%,with an average annual increase of 3.15%.The incidence rate increased from 310.33 per 100,000 to 598.31 per 100,000,a rise of 92.80%,with an average annual increase of 2.55%.The number of prevalent cases increased from 41.04 million to 110 million,a rise of 166.97%,with an average annual increase of 3.61%.The prevalence rate increased from 3488.78 per 100,000 to 7701.69 per 100,000,a rise of 120.76%,with an average annual increase of 3.00%.The number of YLDs increased from 1.34 million to 3.55 million,a rise of 165.32%,with an average annual increase of 3.59%.The YLD rate increased from 113.86 per 100,000 to 249.81 per 100,000,a rise of 119.39%,with an average annual increase of 2.99%.High BMI was the only significant attributable risk factor,with the proportion of YLDs it caused continuing to rise.Predictions for 2035:The number of incident cases is expected to decline slightly from 5.89 million in 2022 to 5.72 million in 2035.The number of prevalent cases is expected to peak at 72.42 million in 2029 and be around 72.69 million in 2035.The number of YLDs is expected to increase year by year,from 2.35 million in 2022 to 2.35 million in 2035.Conclusion:The study reveals the increasing prevalence and disease burden of knee osteoarthritis among Chinese residents,emphasizing the importance of interventions targeting controllable risk factors.Although the prediction shows a slight decline in the number of incident cases in 2035,the number of prevalent cases and years of disability are expected to remain high,indicating the need for continued monitoring and intervention. 展开更多
关键词 Knee osteoarthritis Disease burden Attributable risk factors PREDICTION China
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CMBA-FL: Communication-mitigated and blockchain-assisted federated learning for traffic flow predictions
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作者 Kaiyin Zhu Mingming Lu +2 位作者 Haifeng Li Neal NXiong Wenyong He 《Digital Communications and Networks》 2025年第3期724-733,共10页
As an effective strategy to address urban traffic congestion,traffic flow prediction has gained attention from Federated-Learning(FL)researchers due FL’s ability to preserving data privacy.However,existing methods fa... As an effective strategy to address urban traffic congestion,traffic flow prediction has gained attention from Federated-Learning(FL)researchers due FL’s ability to preserving data privacy.However,existing methods face challenges:some are too simplistic to capture complex traffic patterns effectively,and others are overly complex,leading to excessive communication overhead between cloud and edge devices.Moreover,the problem of single point failure limits their robustness and reliability in real-world applications.To tackle these challenges,this paper proposes a new method,CMBA-FL,a Communication-Mitigated and Blockchain-Assisted Federated Learning model.First,CMBA-FL improves the client model’s ability to capture temporal traffic patterns by employing the Encoder-Decoder framework for each edge device.Second,to reduce the communication overhead during federated learning,we introduce a verification method based on parameter update consistency,avoiding unnecessary parameter updates.Third,to mitigate the risk of a single point of failure,we integrate consensus mechanisms from blockchain technology.To validate the effectiveness of CMBA-FL,we assess its performance on two widely used traffic datasets.Our experimental results show that CMBA-FL reduces prediction error by 11.46%,significantly lowers communication overhead,and improves security. 展开更多
关键词 Blockchain Communication mitigating Federated learning Traffic flow prediction
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OpenPoly:A Polymer Database Empowering Benchmarking and MultipropertyPredictions
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作者 Ji-Feng Wang Yu-Bo Sun +4 位作者 Qiu-Tong Chen Fei-Fan Ji Yuan-Yuan Song Meng-Yuan Ruan Ying Wang 《Chinese Journal of Polymer Science》 2025年第10期1749-1760,共12页
Advancing the integration of artificial intelligence and polymer science requires high-quality,open-source,and large-scale datasets.However,existing polymer databases often suffer from data sparsity,lack of polymer-pr... Advancing the integration of artificial intelligence and polymer science requires high-quality,open-source,and large-scale datasets.However,existing polymer databases often suffer from data sparsity,lack of polymer-property labels,and limited accessibility,hindering system-atic modeling across property prediction tasks.Here,we present OpenPoly,a curated experimental polymer database derived from extensive lit-erature mining and manual validation,comprising 3985 unique polymer-property data points spanning 26 key properties.We further develop a multi-task benchmarking framework that evaluates property prediction using four encoding methods and eight representative models.Our re-sults highlight that the optimized degree-of-polymerization encoding coupled with Morgan fingerprints achieves an optimal trade-off between computational cost and accuracy.In data-scarce condition,XGBoost outperforms deep learning models on key properties such as dielectric con-stant,glass transition temperature,melting point,and mechanical strength,achieving R2 scores of 0.65-0.87.To further showcase the practical utility of the database,we propose potential polymers for two energy-relevant applications:high temperature polymer dielectrics and fuel cell membranes.By offering a consistent and accessible benchmark and database,OpenPoly paves the way for more accurate polymer-property modeling and fosters data-driven advances in polymer genome engineering. 展开更多
关键词 Polymer database Polymer structure encoding Property prediction Functional reverse design Benchmark models
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Vibration signal predictions of damaged sensors on rotor blades based on operational modal analysis and virtual sensing
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作者 Yuhan SUN Zhiguang SONG +2 位作者 Jie LI Guochen CAI Zefeng WANG 《Chinese Journal of Aeronautics》 2025年第6期462-486,共25页
Rotor blade is one of the most significant components of helicopters. But due to its highspeed rotation characteristics, it is difficult to collect the vibration signals during the flight stage.Moreover, sensors are h... Rotor blade is one of the most significant components of helicopters. But due to its highspeed rotation characteristics, it is difficult to collect the vibration signals during the flight stage.Moreover, sensors are highly susceptible to damage resulting in the failure of the measurement.In order to make signal predictions for the damaged sensors, an operational modal analysis(OMA) together with the virtual sensing(VS) technology is proposed in this paper. This paper discusses two situations, i.e., mode shapes measured by all sensors(both normal and damaged) can be obtained using OMA, and mode shapes measured by some sensors(only including normal) can be obtained using OMA. For the second situation, it is necessary to use finite element(FE) analysis to supplement the missing mode shapes of damaged sensor. In order to improve the correlation between the FE model and the real structure, the FE mode shapes are corrected using the local correspondence(LC) principle and mode shapes measured by some sensors(only including normal).Then, based on the VS technology, the vibration signals of the damaged sensors during the flight stage can be accurately predicted using the identified mode shapes(obtained based on OMA and FE analysis) and the normal sensors signals. Given the high degrees of freedom(DOFs) in the FE mode shapes, this approach can also be used to predict vibration data at locations without sensors. The effectiveness and robustness of the proposed method is verified through finite element simulation, experiment as well as the actual flight test. The present work can be further used in the fault diagnosis and damage identification for rotor blade of helicopters. 展开更多
关键词 Composite helicopter rotor blades Operational modal analysis Virtual sensing Vibration prediction Model updating Finite element method
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Machine learning-based performance predictions for steels considering manufacturing process parameters:a review 被引量:2
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作者 Wei Fang Jia-xin Huang +2 位作者 Tie-xu Peng Yang Long Fu-xing Yin 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2024年第7期1555-1581,共27页
Steels are widely used as structural materials,making them essential for supporting our lives and industries.However,further improving the comprehensive properties of steel through traditional trial-and-error methods ... Steels are widely used as structural materials,making them essential for supporting our lives and industries.However,further improving the comprehensive properties of steel through traditional trial-and-error methods becomes challenging due to the continuous development and numerous processing parameters involved in steel production.To address this challenge,the application of machine learning methods becomes crucial in establishing complex relationships between manufacturing processes and steel performance.This review begins with a general overview of machine learning methods and subsequently introduces various performance predictions in steel materials.The classification of performance pre-diction was used to assess the current application of machine learning model-assisted design.Several important issues,such as data source and characteristics,intermediate features,algorithm optimization,key feature analysis,and the role of environmental factors,were summarized and analyzed.These insights will be beneficial and enlightening to future research endeavors in this field. 展开更多
关键词 STEEL Manufacturing process Machine learning Performance prediction Algorithm
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Assessments of Data-Driven Deep Learning Models on One-Month Predictions of Pan-Arctic Sea Ice Thickness 被引量:1
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作者 Chentao SONG Jiang ZHU Xichen LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第7期1379-1390,共12页
In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,ma... In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,mainly due to the limited time coverage of observations and reanalysis data.Meanwhile,deep learning predictions of sea ice thickness(SIT)have yet to receive ample attention.In this study,two data-driven deep learning(DL)models are built based on the ConvLSTM and fully convolutional U-net(FC-Unet)algorithms and trained using CMIP6 historical simulations for transfer learning and fine-tuned using reanalysis/observations.These models enable monthly predictions of Arctic SIT without considering the complex physical processes involved.Through comprehensive assessments of prediction skills by season and region,the results suggest that using a broader set of CMIP6 data for transfer learning,as well as incorporating multiple climate variables as predictors,contribute to better prediction results,although both DL models can effectively predict the spatiotemporal features of SIT anomalies.Regarding the predicted SIT anomalies of the FC-Unet model,the spatial correlations with reanalysis reach an average level of 89%over all months,while the temporal anomaly correlation coefficients are close to unity in most cases.The models also demonstrate robust performances in predicting SIT and SIE during extreme events.The effectiveness and reliability of the proposed deep transfer learning models in predicting Arctic SIT can facilitate more accurate pan-Arctic predictions,aiding climate change research and real-time business applications. 展开更多
关键词 Arctic sea ice thickness deep learning spatiotemporal sequence prediction transfer learning
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Direct Pointwise Comparison of FE Predictions to StereoDIC Measurements:Developments and Validation Using Double Edge-Notched Tensile Specimen
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作者 Troy Myers Michael A.Sutton +2 位作者 Hubert Schreier Alistair Tofts Sreehari Rajan Kattil 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期1263-1298,共36页
To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is... To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process. 展开更多
关键词 StereoDIC spatial co-registration data transformation finite element simulations point-wise comparison of measurements and FEA predictions double edge notch specimen model validation
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Multi-Perspective Data Fusion Framework Based on Hierarchical BERT: Provide Visual Predictions of Business Processes
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作者 Yongwang Yuan Xiangwei Liu Ke Lu 《Computers, Materials & Continua》 SCIE EI 2024年第1期1227-1252,共26页
Predictive Business Process Monitoring(PBPM)is a significant research area in Business Process Management(BPM)aimed at accurately forecasting future behavioral events.At present,deep learning methods are widely cited ... Predictive Business Process Monitoring(PBPM)is a significant research area in Business Process Management(BPM)aimed at accurately forecasting future behavioral events.At present,deep learning methods are widely cited in PBPM research,but no method has been effective in fusing data information into the control flow for multi-perspective process prediction.Therefore,this paper proposes a process prediction method based on the hierarchical BERT and multi-perspective data fusion.Firstly,the first layer BERT network learns the correlations between different category attribute data.Then,the attribute data is integrated into a weighted event-level feature vector and input into the second layer BERT network to learn the impact and priority relationship of each event on future predicted events.Next,the multi-head attention mechanism within the framework is visualized for analysis,helping to understand the decision-making logic of the framework and providing visual predictions.Finally,experimental results show that the predictive accuracy of the framework surpasses the current state-of-the-art research methods and significantly enhances the predictive performance of BPM. 展开更多
关键词 Business process prediction monitoring deep learning attention mechanism BERT multi-perspective
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What control the spatial patterns and predictions of runoff response over the contiguous USA?
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作者 JIANG Shanhu DU Shuping +6 位作者 REN Liliang GONG Xinglong YAN Denghua YUAN Shanshui LIU Yi YANG Xiaoli XU Chongyu 《Journal of Geographical Sciences》 SCIE CSCD 2024年第7期1297-1322,共26页
Understanding the nonlinear relationship between hydrological response and key factors and the cause behind this relationship is vital for water resource management and earth system model.In this study,we undertook se... Understanding the nonlinear relationship between hydrological response and key factors and the cause behind this relationship is vital for water resource management and earth system model.In this study,we undertook several steps to explore the relationship.Initially,we partitioned runoff response change(RRC)into multiple components associated with climate and catchment properties,and examined the spatial patterns and smoothness indicated by the Moran's Index of RRC across the contiguous United States(CONUS).Subsequently,we employed a machine learning model to predict RRC using catchment attribute predictors encompassing climate,topography,hydrology,soil,land use/cover,and geology.Additionally,we identified the primary factors influencing RRC and quantified how these key factors control RRC by employing the accumulated local effect,which allows for the representation of not only dominant but also secondary effects.Finally,we explored the relationship between ecoregion patterns,climate gradients,and the distribution of RRC across CONUS.Our findings indicate that:(1)RRC demonstrating significant connections between catchments tends to be well predicted by catchment attributes in space;(2)climate,hydrology,and topography emerge as the top three key attributes nonlinearly influencing the RRC patterns,with their second-order effects determining the heterogeneous patterns of RRC;and(3)local Moran's I signifies a collaborative relationship between the patterns of RRC and their spatial smoothness,climate space,and ecoregions. 展开更多
关键词 hydrological response prediction machine learning accumulated local effect Moran’s Index large-sample study
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Screening and immune infiltration analysis of ferroptosis-related genes in pancreatic cancer with predictions for traditional Chinese medicine treatments
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作者 Meng-Ru Yang Ying Zhang +3 位作者 Jing-Bai Li Xin-Ru Shen Zi-Yue Pi Zhi-Dong Liu 《Natural Therapy Advances》 CAS 2024年第3期1-13,共13页
Background:This study aims to explore the involvement of ferroptosis-related genes and pathogenesis in pancreatic cancer and predict potential therapeutic interventions using Traditional Chinese Medicine(TCM).Methods:... Background:This study aims to explore the involvement of ferroptosis-related genes and pathogenesis in pancreatic cancer and predict potential therapeutic interventions using Traditional Chinese Medicine(TCM).Methods:We utilized gene expression datasets,ferroptosis upregulated genes and applied machine learning algorithms,including LASSO and SVM-RFE,to identify key ferroptosis-related genes in pancreatic cancer.Perform Gene Ontology,Kyoto Encyclopedia of Genes and Genomes,and Disease Ontology enrichment analysis,immune infiltration analysis and correlation analysis between immune infiltrating cells and characteristic genes on differentially expressed genes using the R software package.Retrieve potential traditional Chinese medicine for targeted ferroptosis gene therapy for pancreatic cancer through Coremine and Herb databases.Results:Seventeen feature genes were identified,with significant implications for immune cell infiltration in pancreatic cancer.The results of immune cell infiltration analysis showed that B cells naive,B cells memory,T cells regulatory,and M0 macrophages were significantly upregulated in pancreatic cancer patients;Mast cells resting were significantly downregulated.Chinese herbal medicines such as ginkgo,turmeric,ginseng,Codonopsis pilosula,Zedoary turmeric,deer tendons,senna leaves,Guanmu Tong,Huangqi,and Banzhilian are potential drugs for targeted ferroptosis gene therapy for pancreatic cancer.Conclusion:TIMP1 emerged as a key gene,with several TCM herbs predicted to modulate its expression,offering new avenues for treatment. 展开更多
关键词 pancreatic cancer ferroptosis immune infiltration BIOINFORMATICS traditional Chinese medicine prediction
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A Deep Learning Model for Insurance Claims Predictions
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作者 Umar Isa Abdulkadir Anil Fernando 《Journal on Artificial Intelligence》 2024年第1期71-83,共13页
One of the significant issues the insurance industry faces is its ability to predict future claims related to individual policyholders.As risk varies from one policyholder to another,the industry has faced the challen... One of the significant issues the insurance industry faces is its ability to predict future claims related to individual policyholders.As risk varies from one policyholder to another,the industry has faced the challenge of using various risk factors to accurately predict the likelihood of claims by policyholders using historical data.Traditional machine-learning models that use neural networks are recognized as exceptional algorithms with predictive capabilities.This study aims to develop a deep learning model using sequential deep regression techniques for insurance claim prediction using historical data obtained from Kaggle with 1339 cases and eight variables.This study adopted a sequential model in Keras and compared the model with ReLU and Swish as activation functions.The performance metrics used during the training to evaluate the model performance are R2 score,mean square error and mean percentage error with values of 0.5%,1.17%and 23.5%,respectively obtained using ReLU,while 0.7%,0.82%,and 21.3%,obtained using Swish function.Although the results of both models using ReLU and Swish were fairly tolerable,the performance metrics obtained of the model using Swish,as the activation function tends to perform more satisfactorily than that of ReLU.However,to investigate the model performance deeply,therefore,this study recommends that more interest be channeled to the interpretability and explainability of the proposed model and the provisions of AI technologies by insurance industries to enhance accurate claim prediction and minimize losses. 展开更多
关键词 Claim predictions INSURANCE deep learning ReLU SWISH artificial intelligence
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大数据智能预测评价 被引量:5
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作者 肖克炎 李程 +4 位作者 唐瑞 王瑶 孙莉 柳炳利 樊铭静 《地学前缘》 北大核心 2025年第4期20-37,共18页
随着大数据时代的到来,大数据技术在矿产勘查中的应用已成为未来发展的趋势。本文系统梳理了大数据找矿和综合信息预测理论的发展历程,探讨了大数据在矿产预测中的关键技术,并结合实际案例,得出以下主要结论:首先,大数据找矿能够有效应... 随着大数据时代的到来,大数据技术在矿产勘查中的应用已成为未来发展的趋势。本文系统梳理了大数据找矿和综合信息预测理论的发展历程,探讨了大数据在矿产预测中的关键技术,并结合实际案例,得出以下主要结论:首先,大数据找矿能够有效应对数据量和复杂性增加的问题,提供更准确的数据解读和预测支持;其次,大数据找矿作为一种技术手段,必须依赖于坚实的矿产找矿理论,特别是综合信息预测理论,后者不仅为大数据方法提供理论支撑,还能提高矿产资源预测的精度和效率;最后,基于综合信息预测理论,结合卷积神经网络(CNN)模型对内蒙古白音查干东山-毛登地区进行成矿预测,展示了其在矿产资源预测中的应用潜力。研究成果为大数据找矿的应用和理论发展提供了重要的参考和实践经验。 展开更多
关键词 大数据 矿产资源预测 机器学习 综合信息矿产预测 智能预测
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河南省高速公路边坡常见灌木生物量估算模型的构建及应用 被引量:1
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作者 徐恩凯 胡永歌 +8 位作者 翟心语 董娜琳 谷翰思 赵明 王华 历从实 田国行 张国育 雷雅凯 《生态学杂志》 北大核心 2025年第1期74-84,共11页
生物量是衡量植被生产力的重要指标,灌木生物量模型是快速估算灌木生物量的重要方法之一。以河南省高速公路边坡3种常见的护坡灌木紫穗槐、荆条和胡枝子为研究对象,基于实地刈割获得植物叶、茎和地上生物量数据,以及对各灌木株高、冠幅... 生物量是衡量植被生产力的重要指标,灌木生物量模型是快速估算灌木生物量的重要方法之一。以河南省高速公路边坡3种常见的护坡灌木紫穗槐、荆条和胡枝子为研究对象,基于实地刈割获得植物叶、茎和地上生物量数据,以及对各灌木株高、冠幅和基径的测算,建立3种灌木叶、茎和地上总生物量的估算模型,根据决定系数(R~2)值的大小、估计值的标准误差(SEE)的大小及回归检验显著水平(P)筛选出最优预测模型,并利用地上生物量最优模型对3种灌木生物量进行了估算。结果表明:3种灌木茎叶比相差不大,为2.57~3.35;3种灌木器官和地上总生物量的最优模型采用的自变量为植株体积(V)、植株高度(H)或基径平方乘以株高(D~2H),最优模型形式多为二次或者三次函数方程。实测值检验显示,建立的3种灌木的函数模型预测生物量的预估精度均达到97%以上,预测精度较好,河南省高速公路边坡灌木地上生物量为6.86×10^(7) kg。研究结果证实,建立的灌木生物量预测模型可应用到高速公路边坡紫穗槐、荆条和胡枝子叶、茎和地上总生物量的估算。 展开更多
关键词 边坡 灌木 生物量 预测模型 预估精度
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融合残差与VMD-TCN-BiLSTM混合网络的鄱阳湖总氮预测 被引量:1
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作者 黄学平 辛攀 +3 位作者 吴永明 吴留兴 邓觅 姚忠 《长江科学院院报》 北大核心 2025年第3期59-67,75,共10页
对湖泊水质进行准确、高效的预测,对于保护水资源、维护生态平衡以及促进经济发展等方面都具有重要意义。为此提出了一种基于模态分解、多维特征选择、时间卷积网络(TCN)、自注意力机制、双向长短期神经网络(BiLSTM)和双向门控循环单元(... 对湖泊水质进行准确、高效的预测,对于保护水资源、维护生态平衡以及促进经济发展等方面都具有重要意义。为此提出了一种基于模态分解、多维特征选择、时间卷积网络(TCN)、自注意力机制、双向长短期神经网络(BiLSTM)和双向门控循环单元(BiGRU)的湖泊总氮(TN)组合预测模型。首先,采用变分模态分解将TN原始序列分解成不同频率的本征模态函数(IMF),以降低原始序列的复杂度和非平稳性;随后,通过随机森林算法为每个IMF选择相关性强的特征,将筛选出的特征矩阵输入到添加自注意力机制的TCN-BiLSTM混合网络中进行建模,充分提取数据中隐藏的关键时序信息;最后,为进一步提升模型预测精度,采用BiGRU网络学习残差序列的细节特征,将残差与模型预测结果融合得到最终的预测值。以鄱阳湖都昌监测站的水质数据为例进行试验分析,结果表明本文模型相比于其他模型对TN浓度预测效果提升明显,其平均绝对误差(MAE)、均方根误差(RMSE)和决定系数(R^(2))分别为0.03 mg/L、0.049 mg/L、0.992。 展开更多
关键词 水质预测 总氮 变分模态分解 时间卷积网络 集成预测
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Classification analysis of prediction skill among ensemble members in MJO subseasonal predictions——based on the results of the CAMS-CSM subseasonal prediction system
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作者 Yihao Peng Xiaolei Liu +1 位作者 Jingzhi Su Xinli Liu 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第4期8-14,共7页
由于模式误差和初始误差所致,次季节-季节预报技巧整体偏低.国际上多数模式都采用集合预报的方式来提高次季节预报的准确率.热带大气季节内振荡(MJO)作为次季节尺度可预报性的重要来源,其预测水平取决于模式性能和MJO事件本身的物理特性... 由于模式误差和初始误差所致,次季节-季节预报技巧整体偏低.国际上多数模式都采用集合预报的方式来提高次季节预报的准确率.热带大气季节内振荡(MJO)作为次季节尺度可预报性的重要来源,其预测水平取决于模式性能和MJO事件本身的物理特性.根据中国气象科学研究院气候系统模式次季节预测系统的回报结果,结合不同类型MJO事件的特征,对模式集合成员间的预报技巧进行了分类和比较.在集合成员预报技巧普遍较高的一类MJO事件中,对流异常信号持续时间较长,强度较大,强对流异常中心主要位于印度洋区域,并逐渐东传至西太平洋.在集合成员预报技巧多数较差的MJO事件中,对流异常信号的强度最弱,维持时间最短.在集合成员预报技巧优劣参半的类别中,MJO往往持续时间较短,强度较低,在后续传播过程中,对流异常中心多停驻在海洋性大陆区域. 展开更多
关键词 次季节-季节预测 预报技巧 热带大气季节内振荡
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基于KNN-SVM的混合气体检测方法研究 被引量:3
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作者 孙超 胡润泽 +2 位作者 吴中旭 刘年松 丁建军 《光谱学与光谱分析》 SCIE EI CAS 北大核心 2025年第1期117-124,共8页
当今混合气体检测的研究中,针对多组分气体数据进行分类预测的数学算法百花齐放,如何快速且准确的检测出气体的成分和浓度逐渐成为当今研究的热门。然而在一些研究中,气体数据特征难以捕捉和判断,泛化能力不足,对气体数据进行分类预测... 当今混合气体检测的研究中,针对多组分气体数据进行分类预测的数学算法百花齐放,如何快速且准确的检测出气体的成分和浓度逐渐成为当今研究的热门。然而在一些研究中,气体数据特征难以捕捉和判断,泛化能力不足,对气体数据进行分类预测的精度和效率表现较差。为此,针对一些数据偏差和泛化误差无界的问题,提出了一种K最近邻-支持向量机(KNN-SVM)算法,对一些难以作出分类的模糊气体数据进行二次分类,采用KNN和SVM两种算法共同抉择,更加全面的捕捉数据特征,根据实验确定各自算法的权重比从而提高判别气体类别的准确率,两种算法的集成也能提高算法的效率,对于不同种类的气体也能有良好的适应性的稳定性。该实验气体组分由12 mg·L^(-1)的C_(2)H_(2)、NO_(2)、SF_(6),10 mg·L^(-1)的NO_(2)、SF_(6)和5 mg·L^(-1)的C_(2)H_(2)(背景气体皆为N_(2))以及两瓶纯N_(2)的气瓶组成;通过互相混合和与N_(2)配比制备出实验设定的气体浓度。实验过程通过单一气体的检测可分别对三种气体获得60组训练集,并通过这60组数据可进行线性拟合得到每种气体的拟合线,得到气体浓度与气体吸收峰值的关系,通过实验检测得到的三种气体拟合线,其中C_(2)H_(2)拟合线的调整后R^(2)为0.991,NO_(2)拟合线的调整后R^(2)为0.981,SF_(6)拟合线的调整后R^(2)为0.987,可得气体检测的准确性。再通过互相混合进行检测可分别获得40组训练集,采用KNN-SVM算法对混合气体进行分类和预测,后通过拟合线即可反演出混合气体中每种气体的浓度。将该算法与传统SVM算法进行各种分类指标对比均可显示出该算法的有效性和优越性。实验结果表明,KNN-SVM算法在气体分类预测方面表现出卓越的性能,准确率高达99.167%,AUC(area under curve)值达99.375%。这一算法不仅提高了气体检测的准确性,还增强了泛化能力可适应多样化的气体组分,为实时气体检测系统提供了有力支持。 展开更多
关键词 光声光谱 气体检测 KNN-SVM 分类预测
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钢轨不平顺焊接区的磨耗及裂纹萌生预测 被引量:4
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作者 林凤涛 王子旭 +3 位作者 谭荣凯 张子豪 杜瑞廷 史志勤 《机械强度》 北大核心 2025年第1期146-154,共9页
为探究钢轨焊接区的磨耗及裂纹萌生与轴重及摩擦因数的关系,通过对大量不平顺焊接区的实地测量,拟合了两种典型焊接区的不平顺数据,建立了上凸和下凹两类典型焊接区不平顺轮轨接触的有限元模型。结合摩擦功模型和Archard磨耗理论,对焊... 为探究钢轨焊接区的磨耗及裂纹萌生与轴重及摩擦因数的关系,通过对大量不平顺焊接区的实地测量,拟合了两种典型焊接区的不平顺数据,建立了上凸和下凹两类典型焊接区不平顺轮轨接触的有限元模型。结合摩擦功模型和Archard磨耗理论,对焊接区最大磨耗截面进行预测,基于Jiang-Sehitoglu模型对焊接区裂纹萌生寿命进行预测。发现随着轴重的增加,上凸及下凹焊接区的磨耗速率均增大;且轴重达到16 t时上凸型焊接区磨耗速率显著增大,而下凹型焊接区在轴重达到18 t时磨耗速率显著增大;摩擦因数从0.2增加到0.35,上凸和下凹两类焊接区最大磨耗量分别为1.93 mm、1.08 mm;且上凸型焊接区磨耗速率在摩擦因数为0.3时显著增大,而下凹型焊接区磨耗速率在摩擦因数为0.35时显著增大。轴重从12 t增加到18 t,上凸型焊接区服役寿命的衰减幅度较小,而下凹型焊接区服役寿命衰减幅度较大。此外,当摩擦因数从0.2增加至0.35时,其对上凸型焊接区服役寿命的影响明显小于轴重(12~18 t)的影响。然而,当摩擦因数从0.2增加至0.35时,其对下凹型焊接区服役寿命的影响与轴重(12~18 t)的影响相当。结果表明,随着轴重和摩擦因数的增加,对钢轨焊接区下凹型不平顺的寿命影响更加显著;在工务维护过程中,应着重关注下凹型焊接区的出现并及时标记和修复。 展开更多
关键词 铁道工程 轮轨关系 磨耗预测 裂纹萌生预测
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全株玉米青贮营养成分含量近红外光谱预测模型的建立 被引量:2
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作者 潘发明 郭涛 +2 位作者 李飞 郝生燕 刘佳 《中国草食动物科学》 北大核心 2025年第3期62-68,共7页
本研究基于近红外光谱(NIRS)技术,以数学和化学计量学方式分析光谱数据,构建全株玉米青贮营养成分含量近红外预测模型,为实际生产中高效合理利用全株玉米青贮饲料提供理论依据与技术支撑。从西北5个省区共采集190份全株玉米青贮,测定干... 本研究基于近红外光谱(NIRS)技术,以数学和化学计量学方式分析光谱数据,构建全株玉米青贮营养成分含量近红外预测模型,为实际生产中高效合理利用全株玉米青贮饲料提供理论依据与技术支撑。从西北5个省区共采集190份全株玉米青贮,测定干物质(DM)、淀粉(Starch)、粗蛋白质(CP)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、粗脂肪(EE)和粗灰分(Ash)含量;根据Kennard-stone方法将所有样品按照4∶1随机分为定标集和验证集,通过主成分分析剔除异常光谱,并结合数学和化学计量学分别构建各营养成分预测模型,同时进行外部验证。结果表明,ADF含量预测模型的交互验证相关系数(1-VR)和预测决定系数(RSQ)分别为0.946 7和0.90,可以用于饲料检测中的精确预测。CP、Ash和DM含量预测模型的1-VR分别为0.634 4、0.777 3和0.747 0,RSQ分别为0.68、0.70和0.71,可以用于实际生产中的预测。NDF含量预测模型的1-VR和RSQ分别为0.289 4和0.39,预测准确性较低,模型还需进一步优化。EE和Starch预测模型的1-VR分别为0.181 0和0.170 5,预测模型不可用。 展开更多
关键词 全株玉米青贮 营养成分 近红外预测模型
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