期刊文献+
共找到1,508篇文章
< 1 2 76 >
每页显示 20 50 100
Long-term settlement prediction of high-speed railway bridge pile foundation 被引量:4
1
作者 杨奇 冷伍明 +4 位作者 张升 聂如松 魏丽敏 赵春彦 刘维正 《Journal of Central South University》 SCIE EI CAS 2014年第6期2415-2424,共10页
The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis,and the corresponding loading function was presented.One-dimensiona... The process and characteristics of loading on high-speed railway bridge pile foundation were firstly obtained by means of field research and analysis,and the corresponding loading function was presented.One-dimensional consolidation equation of elastic multilayered soils was then established with single drainage or double drainages under multilevel loading.Moreover,the formulas for calculating effective stress and settlement were derived from the Laplace numerical inversion transform.The three-dimensional composite analysis method of bridge pile group was improved,where the actual load conditions of pile foundation could be simulated,and the consolidation characteristics of soil layers beneath pile were also taken into account.Eventually,a corresponding program named LTPGS was developed to improve the calculation efficiency.The comparison between long-term settlement obtained from the proposed method and the in-situ measurements of pile foundation was illustrated,and a close agreement is obtained.The error between computed and measured results is less than 1 mm,and it gradually reduces with time.It is shown that the proposed method can effectively simulate the long-term settlement of pile foundation and program LTPGS can provide a reliable estimation. 展开更多
关键词 bridge pile foundation long-term settlement CONSOLIDATION Laplace numerical inversion transform multilevel loading multilayered soils
下载PDF
Prediction of high-embankment settlement combining joint denoising technique and enhanced GWO-v-SVR method
2
作者 Qi Zhang Qian Su +2 位作者 Zongyu Zhang Zhixing Deng De Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第1期317-332,共16页
Reliable long-term settlement prediction of a high embankment relates to mountain infrastructure safety.This study developed a novel hybrid model(NHM)that combines a joint denoising technique with an enhanced gray wol... Reliable long-term settlement prediction of a high embankment relates to mountain infrastructure safety.This study developed a novel hybrid model(NHM)that combines a joint denoising technique with an enhanced gray wolf optimizer(EGWO)-n-support vector regression(n-SVR)method.High-embankment field measurements were preprocessed using the joint denoising technique,which in-cludes complete ensemble empirical mode decomposition,singular value decomposition,and wavelet packet transform.Furthermore,high-embankment settlements were predicted using the EGWO-n-SVR method.In this method,the standard gray wolf optimizer(GWO)was improved to obtain the EGWO to better tune the n-SVR model hyperparameters.The proposed NHM was then tested in two case studies.Finally,the influences of the data division ratio and kernel function on the EGWO-n-SVR forecasting performance and prediction efficiency were investigated.The results indicate that the NHM suppresses noise and restores details in high-embankment field measurements.Simultaneously,the NHM out-performs other alternative prediction methods in prediction accuracy and robustness.This demonstrates that the proposed NHM is effective in predicting high-embankment settlements with noisy field mea-surements.Moreover,the appropriate data division ratio and kernel function for EGWO-n-SVR are 7:3 and radial basis function,respectively. 展开更多
关键词 High embankment settlement prediction Joint denoising technique Enhanced gray wolf optimizer Support vector regression
下载PDF
The long-term prediction of the oil-contaminated water from the Sanchi collision in the East China Sea 被引量:10
3
作者 YIN Liping ZHANG Min +1 位作者 ZHANG Yuanling QIAO Fangli 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2018年第3期69-72,共4页
The condensate and bunker oil leaked from the Sanchi collision would cause a persistent impact on marine ecosystems in the surrounding areas. The long-term prediction for the distribution of the oil-polluted water and... The condensate and bunker oil leaked from the Sanchi collision would cause a persistent impact on marine ecosystems in the surrounding areas. The long-term prediction for the distribution of the oil-polluted water and the information for the most affected regions would provide valuable information for the oceanic environment protection and pollution assessment. Based on the operational forecast system developed by the First Institute of Oceanography, State Oceanic Administration, we precisely predicted the drifting path of the oil tanker Sanchi after its collision. Trajectories of virtual oil particles show that the oil leaked from the Sanchi after it sank is mainly transported to the northeastern part of the sink location, and quickly goes to the open ocean along with the Kuroshio. Risk probability analysis based on the outcomes from the operational forecast system for years 2009 to2017 shows that the most affected area is at the northeast of the sink location. 展开更多
关键词 Sanchi collision long-term prediction oil spill
下载PDF
Long-term Traffic Volume Prediction Based on K-means Gaussian Interval Type-2 Fuzzy Sets 被引量:10
4
作者 Runmei Li Yinfeng Huang Jian Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第6期1344-1351,共8页
This paper uses Gaussian interval type-2 fuzzy se theory on historical traffic volume data processing to obtain a 24-hour prediction of traffic volume with high precision. A K-means clustering method is used in this p... This paper uses Gaussian interval type-2 fuzzy se theory on historical traffic volume data processing to obtain a 24-hour prediction of traffic volume with high precision. A K-means clustering method is used in this paper to get 5 minutes traffic volume variation as input data for the Gaussian interval type-2 fuzzy sets which can reflect the distribution of historical traffic volume in one statistical period. Moreover, the cluster with the largest collection of data obtained by K-means clustering method is calculated to get the key parameters of type-2 fuzzy sets, mean and standard deviation of the Gaussian membership function.Using the range of data as the input of Gaussian interval type-2 fuzzy sets leads to the range of traffic volume forecasting output with the ability of describing the possible range of the traffic volume as well as the traffic volume prediction data with high accuracy. The simulation results show that the average relative error is reduced to 8% based on the combined K-means Gaussian interval type-2 fuzzy sets forecasting method. The fluctuation range in terms of an upper and a lower forecasting traffic volume completely envelopes the actual traffic volume and reproduces the fluctuation range of traffic flow. 展开更多
关键词 GAUSSIAN interval type-2 fuzzy sets K-MEANS clustering long-term prediction TRAFFIC VOLUME TRAFFIC VOLUME fluctuation range
下载PDF
A simplified method for prediction of embankment settlement in clays 被引量:2
5
作者 Chunlin Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2014年第1期61-66,共6页
The prediction of embankment settlement is a critically important issue for the serviceability of subgrade projects,especially the post-construction settlement.A number of methods have been proposed to predict embankm... The prediction of embankment settlement is a critically important issue for the serviceability of subgrade projects,especially the post-construction settlement.A number of methods have been proposed to predict embankment settlement;however,all of these methods are based on a parameter,i.e.the initial time point.The difference of the initial time point determined by different designers can de?nitely induce errors in prediction of embankment settlement.This paper proposed a concept named"potential settlement"and a simpli?ed method based on the in situ data.The key parameter"b"in the proposed method was veri?ed using theoretical method and?eld data.Finally,an example was used to demonstrate the advantages of the proposed method by comparing with other methods and the observation data. 展开更多
关键词 Simplified method settlement prediction EMBANKMENT Consolidation theory Clayey soil
下载PDF
Settlement Prediction of Dredger Fill with the Optimal Combination Model 被引量:2
6
作者 王清 闫欢 +2 位作者 苑晓青 牛岑岑 张旭东 《Journal of Donghua University(English Edition)》 EI CAS 2014年第6期812-816,共5页
Post-construction settlement has gained increasing attention because it frequently causes engineering problems. A combined model is a commonly used prediction model that overcomes the difficulty of a single model( i. ... Post-construction settlement has gained increasing attention because it frequently causes engineering problems. A combined model is a commonly used prediction model that overcomes the difficulty of a single model( i. e., cannot reflect various regulations of settlement at some stages or the entire process). In this study,the correlation coefficient,maximum error values,and other values were obtained according to the fitting and predicted results of a single model. The coefficient of variation was then introduced to determine the weight of each model forming the combination. The proposed model was used to fit and predict for settlement and overcome the issue of utilizing a single model while determining the weight. The fitting predictive effect was also analyzed using the settlement fitting precision results. The fitting precision of optimizing the combination model is high. The predicted data of the post-construction settlement are closer to the calculated value of the settlement monitoring data. Moreover,the proposed model has good practicability,does not require the interval data of settlement,and restricts the model number. Thus,this model can be applied in the engineering field. 展开更多
关键词 dredger fill settlement prediction combination model coefficient of variation WEIGHT
下载PDF
Settlement Prediction for Buildings Surrounding Foundation Pits Based on a Stationary Auto-regression Model 被引量:3
7
作者 TIAN Lin-ya HUA Xi-sheng 《Journal of China University of Mining and Technology》 EI 2007年第1期78-81,共4页
To ensure the safety of buildings surrounding foundation pits, a study was made on a settlement monitoring and trend prediction method. A statistical testing method for analyzing the stability of a settlement monitori... To ensure the safety of buildings surrounding foundation pits, a study was made on a settlement monitoring and trend prediction method. A statistical testing method for analyzing the stability of a settlement monitoring datum has been discussed. According to a comprehensive survey, data of 16 stages at operating control point, were verified by a standard t test to determine the stability of the operating control point. A stationary auto-regression model, AR(p), used for the observation point settlement prediction has been investigated. Given the 16 stages of the settlement data at an observation point, the applicability of this model was analyzed. Settlement of last four stages was predicted using the stationary auto-regression model AR (1); the maximum difference between predicted and measured values was 0.6 mm, indicating good prediction results of the model. Hence, this model can be applied to settlement predictions for buildings surrounding foundation pits. 展开更多
关键词 foundation pit BUILDING settlement monitoring datum stability stationary auto-regression model settlement prediction
下载PDF
Settlement prediction model of slurry suspension based on sedimentation rate attenuation 被引量:1
8
作者 Shuai-jie GUO Fu-hai ZHANG +1 位作者 Bao-tian WANG Chao ZHANG 《Water Science and Engineering》 EI CAS 2012年第1期79-92,共14页
This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling... This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling particles are significantly different in the process of sedimentation rate attenuation, and the settlement process includes the free sedimentation stage, the log-linear attenuation stage, and the stable consolidation stage according to sedimentation rate attenuation. Settlement equations for sedimentation height and time were established based on sedimentation rate attenuation properties of different sedimentation stages. Finally, a slurry suspension settlement prediction model based on slurry parameters was set up with a foundation being that the model parameters were determined by the basic parameters of slurry. The results of the settlement prediction model show good agreement with those of the settlement column experiment and reflect the main characteristics of cohesive sediment. The model can be applied to the prediction of cohesive soil settlement in still water environments. 展开更多
关键词 cohesive sediment sedimentation rate attenuation slurry suspension settlement prediction model settlement column experiment
下载PDF
Development of a new Cox model for predicting long-term survival in hepatitis cirrhosis patients underwent transjugular intrahepatic portosystemic shunts
9
作者 Yi-Fan Lv Bing Zhu +8 位作者 Ming-Ming Meng Yi-Fan Wu Cheng-Bin Dong Yu Zhang Bo-Wen Liu Shao-Li You Sa Lv Yong-Ping Yang Fu-Quan Liu 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第2期491-502,共12页
BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)placement is a procedure that can effectively treat complications of portal hypertension,such as variceal bleeding and refractory ascites.However,there hav... BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)placement is a procedure that can effectively treat complications of portal hypertension,such as variceal bleeding and refractory ascites.However,there have been no specific studies on predicting long-term survival after TIPS placement.AIM To establish a model to predict long-term survival in patients with hepatitis cirrhosis after TIPS.METHODS A retrospective analysis was conducted on a cohort of 224 patients who un-derwent TIPS implantation.Through univariate and multivariate Cox regression analyses,various factors were examined for their ability to predict survival at 6 years after TIPS.Consequently,a composite score was formulated,encompassing the indication,shunt reasonability,portal venous pressure gradient(PPG)after TIPS,percentage decrease in portal venous pressure(PVP),indocyanine green retention rate at 15 min(ICGR15)and total bilirubin(Tbil)level.Furthermore,the performance of the newly developed Cox(NDC)model was evaluated in an in-ternal validation cohort and compared with that of a series of existing models.RESULTS The indication(variceal bleeding or ascites),shunt reasonability(reasonable or unreasonable),ICGR15,post-operative PPG,percentage of PVP decrease and Tbil were found to be independent factors affecting long-term survival after TIPS placement.The NDC model incorporated these parameters and successfully identified patients at high risk,exhibiting a notably elevated mortality rate following the TIPS procedure,as observed in both the training and validation cohorts.Additionally,in terms of predicting the long-term survival rate,the performance of the NDC model was significantly better than that of the other four models[Child-Pugh,model for end-stage liver disease(MELD),MELD-sodium and the Freiburg index of post-TIPS survival].CONCLUSION The NDC model can accurately predict long-term survival after the TIPS procedure in patients with hepatitis cirrhosis,help identify high-risk patients and guide follow-up management after TIPS implantation. 展开更多
关键词 Transjugular intrahepatic portosystemic shunt long-term survival predictive model
下载PDF
Analysis and Prediction of Foundation Settlement of High-Rise Buildings under Complex Geological Conditions
10
作者 Jihui Ding Bingjun Li +2 位作者 Erxia Du Weiyu Wang Tuo Zhao 《World Journal of Engineering and Technology》 2017年第3期445-454,共10页
Based on an example of a project in Tangshan, the high-rise buildings are built in karst area and mined out affected area which is treated by high pressure grouting, and foundation is adopted the form of pile raft fou... Based on an example of a project in Tangshan, the high-rise buildings are built in karst area and mined out affected area which is treated by high pressure grouting, and foundation is adopted the form of pile raft foundation. By long-term measured settlement of high-rise buildings, It is found that foundation settlement is linear increase with the increase of load before the building is roof-sealed, and the settlement increases slowly after the building is roof-sealed, and the curve tends to converge, and the foundation consolidation is completed. The settlement of the foundation is about 80% - 84% of the total settlement before the building is roof-sealed.Three layer BP neural network model is used to predict the settlement in the karst area and mined affected area.Compared with the measured data, the relative difference of the prediction is 0.91% - 2.08% in the karst area, and is 0.95% - 2.11% in mined affected area. The prediction results of high precision can meet the engineering requirements. 展开更多
关键词 COMPLEX GEOLOGICAL Conditions settlement LAW settlement prediction The BP Neural Network
下载PDF
New scheme of anticipating synchronization for arbitrary anticipation time and its application to long-term prediction of chaotic states
11
作者 孙中奎 徐伟 杨晓丽 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第11期3226-3230,共5页
How to predict the dynamics of nonlinear chaotic systems is still a challenging subject with important real-life applications. The present paper deals with this important yet difficult problem via a new scheme of anti... How to predict the dynamics of nonlinear chaotic systems is still a challenging subject with important real-life applications. The present paper deals with this important yet difficult problem via a new scheme of anticipating synchronization. A global, robust, analytical and delay-independent sufficient condition is obtained to guarantee the existence of anticipating synchronization manifold theoretically in the framework of the Krasovskii-Lyapunov theory. Different from 'traditional techniques (or regimes)' proposed in the previous literature, the present scheme guarantees that the receiver system can synchronize with the future state of a transmitter system for an arbitrarily long anticipation time, which allows one to predict the dynamics of chaotic transmitter at any point of time if necessary. Also it is simple to implement in practice. A classical chaotic system is employed to demonstrate the application of the proposed scheme to the long-term prediction of chaotic states. 展开更多
关键词 anticipating synchronization long-term predictability chaotic systems
下载PDF
Long-term Prediction and Verification of Rainfall Based on the Seasonal Model
12
作者 Zheng Xiaohua Li Xingmin 《Meteorological and Environmental Research》 CAS 2014年第5期13-14,21,共3页
Using the seasonal cross-multiplication trend model, monthly precipitation of eight national basic weather stations of Shaanxi Province from 2005 to 2010 was predicted, and the forecast results were verified using the... Using the seasonal cross-multiplication trend model, monthly precipitation of eight national basic weather stations of Shaanxi Province from 2005 to 2010 was predicted, and the forecast results were verified using the rainfall scoring rules of China Meteorological Administration. The verification results show that the average score of annual precipitation prediction in recent six years is higher than that made by a professional forecaster, so this model has a good prospect of application. Moreover, the level of making prediction is steady, and it can be widely used in long-term prediction of rainfall. 展开更多
关键词 Seasonal cross-multiplication trend model long-term prediction of rainfall Forecast verification China
下载PDF
Deformation prediction model of concrete face rockfill dams based on an improved random forest model 被引量:9
13
作者 Yan-long Li Qiao-gang Yin +1 位作者 Ye Zhang Heng Zhou 《Water Science and Engineering》 EI CAS CSCD 2023年第4期390-398,共9页
The unique structure and complex deformation characteristics of concrete face rockfill dams(CFRDs)create safety monitoring challenges.This study developed an improved random forest(IRF)model for dam health monitoring ... The unique structure and complex deformation characteristics of concrete face rockfill dams(CFRDs)create safety monitoring challenges.This study developed an improved random forest(IRF)model for dam health monitoring modeling by replacing the decision tree in the random forest(RF)model with a novel M5'model tree algorithm.The factors affecting dam deformation were preliminarily selected using the statistical model,and the grey relational degree theory was utilized to reduce the dimensions of model input variables.Finally,a deformation prediction model of CFRDs was established using the IRF model.The ten-fold cross-validation method was used to quantitatively analyze the parameters affecting the IRF algorithm.The performance of the established model was verified using data from three specific measurement points on the Jishixia dam and compared with other dam deformation prediction models.At point ES-10,the performance evaluation indices of the IRF model were superior to those of the M5'model tree and RF models and the classical support vector regression(SVR)and back propagation(BP)neural network models,indicating the satisfactory performance of the IRF model.The IRF model also outperformed the SVR and BP models in settlement prediction at points ES2-8 and ES4-10,demonstrating its strong anti-interference and generalization capabilities.This study has developed a novel method for forecasting and analyzing dam settlements with practical significance.Moreover,the established IRF model can also provide guidance for modeling health monitoring of other structures. 展开更多
关键词 Dam health monitoring M5'model tree IRF Monitoring models settlement prediction
下载PDF
A Lightweight Temporal Convolutional Network for Human Motion Prediction 被引量:1
14
作者 WANG You QIAO Bing 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第S01期150-157,共8页
A lightweight multi-layer residual temporal convolutional network model(RTCN)is proposed to target the highly complex kinematics and temporal correlation of human motion.RTCN uses 1-D convolution to efficiently obtain... A lightweight multi-layer residual temporal convolutional network model(RTCN)is proposed to target the highly complex kinematics and temporal correlation of human motion.RTCN uses 1-D convolution to efficiently obtain the spatial structure information of human motion and extract the correlation in the time series of human motion.The residual structure is applied to the proposed network model to alleviate the problem of gradient disappearance in the deep network.Experiments on the Human 3.6M dataset demonstrate that the proposed method effectively reduces the errors of motion prediction compared with previous methods,especially of long-term prediction. 展开更多
关键词 human motion prediction temporal convolutional network short-term prediction long-term prediction deep neural network
下载PDF
Predicting and validating the load-settlement behavior of large-scale geosynthetic-reinforced soil abutments using hybrid intelligent modeling 被引量:1
15
作者 Muhammad Nouman Amjad Raja Syed Taseer Abbas Jaffar +1 位作者 Abidhan Bardhan Sanjay Kumar Shukla 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第3期773-788,共16页
Settlement prediction of geosynthetic-reinforced soil(GRS)abutments under service loading conditions is an arduous and challenging task for practicing geotechnical/civil engineers.Hence,in this paper,a novel hybrid ar... Settlement prediction of geosynthetic-reinforced soil(GRS)abutments under service loading conditions is an arduous and challenging task for practicing geotechnical/civil engineers.Hence,in this paper,a novel hybrid artificial intelligence(AI)-based model was developed by the combination of artificial neural network(ANN)and Harris hawks’optimisation(HHO),that is,ANN-HHO,to predict the settlement of the GRS abutments.Five other robust intelligent models such as support vector regression(SVR),Gaussian process regression(GPR),relevance vector machine(RVM),sequential minimal optimisation regression(SMOR),and least-median square regression(LMSR)were constructed and compared to the ANN-HHO model.The predictive strength,relalibility and robustness of the model were evaluated based on rigorous statistical testing,ranking criteria,multi-criteria approach,uncertainity analysis and sensitivity analysis(SA).Moreover,the predictive veracity of the model was also substantiated against several large-scale independent experimental studies on GRS abutments reported in the scientific literature.The acquired findings demonstrated that the ANN-HHO model predicted the settlement of GRS abutments with reasonable accuracy and yielded superior performance in comparison to counterpart models.Therefore,it becomes one of predictive tools employed by geotechnical/civil engineers in preliminary decision-making when investigating the in-service performance of GRS abutments.Finally,the model has been converted into a simple mathematical formulation for easy hand calculations,and it is proved cost-effective and less time-consuming in comparison to experimental tests and numerical simulations. 展开更多
关键词 Geosynthetic-reinforced soil(GRS) ABUTMENTS settlement estimation predictive modeling Artificial intelligence(AI) Artificial neural network(ANN)-Harris hawks’optimisation(HHO)
下载PDF
Lithium-ion battery degradation trajectory early prediction with synthetic dataset and deep learning
16
作者 Mingqiang Lin Yuqiang You +3 位作者 Jinhao Meng Wei Wang Ji Wu Daniel-Ioan Stroe 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第10期534-546,I0013,共14页
Knowing the long-term degradation trajectory of Lithium-ion(Li-ion) battery in its early usage stage is critical for the maintenance of the battery energy storage system(BESS) in reality. Previous battery health diagn... Knowing the long-term degradation trajectory of Lithium-ion(Li-ion) battery in its early usage stage is critical for the maintenance of the battery energy storage system(BESS) in reality. Previous battery health diagnosis methods focus on capacity and state of health(SOH) estimation which can receive only the short-term health status of the cell. This paper proposes a novel degradation trajectory prediction method with synthetic dataset and deep learning, which enables to grasp the characterization of the cell's health at a very early stage of Li-ion battery usage. A transferred convolutional neural network(CNN) is chosen to finalize the early prediction target, and the polynomial function based synthetic dataset generation strategy is designed to reduce the costly data collection procedure in real application. In this thread, the proposed method needs one full lifespan data to predict the overall degradation trajectories of other cells. With only the full lifespan cycling data from 4 cells and 100 cycling data from each cell in experimental validation, the proposed method shows a good prediction accuracy on a dataset with more than 100 commercial Li-ion batteries. 展开更多
关键词 Lithium-ion battery Degradation trajectory long-term prediction Transferred convolutional neural network
下载PDF
A Neuro-Based Software Fault Prediction with Box-Cox Power Transformation
17
作者 Momotaz Begum Tadashi Dohi 《Journal of Software Engineering and Applications》 2017年第3期288-309,共22页
Software fault prediction is one of the most fundamental but significant management techniques in software dependability assessment. In this paper we concern the software fault prediction using a multilayer-perceptron... Software fault prediction is one of the most fundamental but significant management techniques in software dependability assessment. In this paper we concern the software fault prediction using a multilayer-perceptron neural network, where the underlying software fault count data are transformed to the Gaussian data, by means of the well-known Box-Cox power transformation. More specially, we investigate the long-term behavior of software fault counts by the neural network, and perform the multi-stage look ahead prediction of the cumulative number of software faults detected in the future software testing. In numerical examples with two actual software fault data sets, we compare our neural network approach with the existing software reliability growth models based on nonhomogeneous Poisson process, in terms of predictive performance with average relative error, and show that the data transformation employed in this paper leads to an improvement in prediction accuracy. 展开更多
关键词 Software Reliability Artificial NEURAL Network Box-Cox Power Transformation long-term prediction FAULT COUNT Data Empirical Validation
下载PDF
National Prediction of Ambient Fine Particulates: 2000-2009
18
作者 David J. Shavlik Sam Soret +2 位作者 W. Lawrence Beeson Mark G. Ghamsary Synnove F. Knutsen 《Open Journal of Air Pollution》 2016年第3期95-108,共15页
A large body of evidence links ambient fine particulates (PM<sub>2.5</sub>) to chronic disease. Efforts continue to be made to improve large scale estimation of this pollutant for within-urban environments... A large body of evidence links ambient fine particulates (PM<sub>2.5</sub>) to chronic disease. Efforts continue to be made to improve large scale estimation of this pollutant for within-urban environments and sparsely monitored areas. Still questions remain about modeling choices. The purpose of this study was to evaluate the performance of spatial only models in predicting national monthly exposure estimates of fine particulate matter at different time aggregations during the time period 2000-2009 for the contiguous United States. Additional goals were to evaluate the difference in prediction between federal reference monitors and non-reference monitors, assess regional differences, and compare with traditional methods. Using spatial generalized additive models (GAM), national models for fine particulate matter were developed, incorporating geographical information systems (GIS)-derived covariates and meteorological variables. Results were compared to nearest monitor and inverse distance weighting at different time aggregations and a comparison was made between the Federal Reference Method and all monitors. Cross-validation was used for model evaluation. Using all monitors, the cross-validated R<sup>2</sup> was 0.76, 0.81, and 0.82 for monthly, 1 year, and 5-year aggregations, respectively. A small decrease in performance was observed when selecting Federal Reference monitors only (R<sup>2</sup> = 0.73, 0.78, and 0.80 respectively). For Inverse distance weighting (IDW), there was a significantly larger decrease in R<sup>2</sup> (0.68, 0.71, and 0.73, respectively). The spatial GAM showed the weakest performance for the northwest region. In conclusion, National exposure estimates of fine particulates at different time aggregations can be significantly improved over traditional methods by using spatial GAMs that are relatively easy to produce. Furthermore, these models are comparable in performance to other national prediction models. 展开更多
关键词 long-term Air Pollution GAM prediction Fine Particulates
下载PDF
Shield Excavation Analysis: Ground Settlement & Mechanical Responses in Complex Strata
19
作者 Baojun Qin Guangwei Zhang Wei Zhang 《Structural Durability & Health Monitoring》 EI 2024年第3期341-360,共20页
This study delves into the effects of shield tunneling in complex coastal strata, focusing on how this constructionmethod impacts surface settlement, the mechanical properties of adjacent rock, and the deformation of ... This study delves into the effects of shield tunneling in complex coastal strata, focusing on how this constructionmethod impacts surface settlement, the mechanical properties of adjacent rock, and the deformation of tunnelsegments. It investigates the impact of shield construction on surface settlement, mechanical characteristics ofnearby rock, and segment deformation in complex coastal strata susceptible to construction disturbances. Utilizingthe Fuzhou Binhai express line as a case study, we developed a comprehensive numerical model using theABAQUS finite element software. The model incorporates factors such as face force, grouting pressure, jack force,and cutterhead torque. Its accuracy is validated against field monitoring data from engineering projects. Simulationswere conducted to analyze ground settlement and mechanical changes in adjacent rock and segments acrossfive soil layers. The results indicate that disturbances are most significant near the excavation zone of the shieldmachine, with a prominent settlement trough forming and stabilizing around 2.0–3.0 D from the excavation. Theexcavation face compresses the soil, inducing lateral expansion. As grouting pressure decreases, the segmentexperiences upward buoyancy. In mixed strata, softer layers witness increased cutting, intensifying disturbancesbut reducing segment floatation. These findings offer valuable insights for predicting settlements, ensuring segmentand rock safety, and optimizing tunneling parameters. 展开更多
关键词 Shield construction complex strata finite element method mechanical properties of surrounding rock segment deformation settlement prediction
下载PDF
Quantitative electroencephalography in predicting on outcome of awakening in long-term unconscious patients after severe traumatic brain injury
20
作者 陈燕伟 《外科研究与新技术》 2011年第3期200-200,共1页
Objective To explore quantitative electroencephalography in unconscious patients after severe traumatic brain injury (TBI) to predict awakening. Methods All cases were divided into two groups(the awake group 19 cases ... Objective To explore quantitative electroencephalography in unconscious patients after severe traumatic brain injury (TBI) to predict awakening. Methods All cases were divided into two groups(the awake group 19 cases and the unfavourable prognosis group 22 cases).Two weeks after admission the original EEGs were preformed in 41 patients suffering from severe TBI with duration of disturbance of 展开更多
关键词 TBI Quantitative electroencephalography in predicting on outcome of awakening in long-term unconscious patients after severe traumatic brain injury
下载PDF
上一页 1 2 76 下一页 到第
使用帮助 返回顶部