当前我国空气污染形势日益严峻,空气质量的急剧下降致使人们的身体健康受到严重地危害,同时也妨碍了社会和经济的可持续发展。对PM_(2.5)浓度进行预测,从而监督空气污染状况,防止严重污染的发生受到我国及世界各国人民的广泛关注。因此...当前我国空气污染形势日益严峻,空气质量的急剧下降致使人们的身体健康受到严重地危害,同时也妨碍了社会和经济的可持续发展。对PM_(2.5)浓度进行预测,从而监督空气污染状况,防止严重污染的发生受到我国及世界各国人民的广泛关注。因此提出有效的模型对PM_(2.5)浓度进行准确预测成为时下一个重要问题。本文提出了PLS-M5P(Partial Least Square-M5P)模型用于PM_(2.5)浓度预测。实验结果表明,在空气质量预测方面,与传统的预测模型如BP神经模型相比,PLS-M5P模型树有以下几个优势:(1)能提供直观的数学方程,并能够从获得的数学方程中更深入地理解预测结果。(2)使用PLS-M5P模型生成的树状图可以显示因素的重要性,并且树状图的建立能使决策者更清晰地认识预测过程。(3)建模和预测所用时间很短,而且总是收敛的。(4)预测的精度更高。展开更多
The most common index for representing structural condition of the pavement is the structural number.The current procedure for determining structural numbers involves utilizing falling weight deflectometer and ground-...The most common index for representing structural condition of the pavement is the structural number.The current procedure for determining structural numbers involves utilizing falling weight deflectometer and ground-penetrating radar tests,recording pavement surface deflections,and analyzing recorded deflections by back-calculation manners.This procedure has two drawbacks:falling weight deflectometer and ground-penetrating radar are expensive tests;back-calculation ways has some inherent shortcomings compared to exact methods as they adopt a trial and error approach.In this study,three machine learning methods entitled Gaussian process regression,M5P model tree,and random forest used for the prediction of structural numbers in flexible pavements.Dataset of this paper is related to 759 flexible pavement sections at Semnan and Khuzestan provinces in Iran and includes“structural number”as output and“surface deflections and surface temperature”as inputs.The accuracy of results was examined based on three criteria of R,MAE,and RMSE.Among the methods employed in this paper,random forest is the most accurate as it yields the best values for above criteria(R=0.841,MAE=0.592,and RMSE=0.760).The proposed method does not require to use ground penetrating radar test,which in turn reduce costs and work difficulty.Using machine learning methods instead of back-calculation improves the calculation process quality and accuracy.展开更多
文摘当前我国空气污染形势日益严峻,空气质量的急剧下降致使人们的身体健康受到严重地危害,同时也妨碍了社会和经济的可持续发展。对PM_(2.5)浓度进行预测,从而监督空气污染状况,防止严重污染的发生受到我国及世界各国人民的广泛关注。因此提出有效的模型对PM_(2.5)浓度进行准确预测成为时下一个重要问题。本文提出了PLS-M5P(Partial Least Square-M5P)模型用于PM_(2.5)浓度预测。实验结果表明,在空气质量预测方面,与传统的预测模型如BP神经模型相比,PLS-M5P模型树有以下几个优势:(1)能提供直观的数学方程,并能够从获得的数学方程中更深入地理解预测结果。(2)使用PLS-M5P模型生成的树状图可以显示因素的重要性,并且树状图的建立能使决策者更清晰地认识预测过程。(3)建模和预测所用时间很短,而且总是收敛的。(4)预测的精度更高。
文摘The most common index for representing structural condition of the pavement is the structural number.The current procedure for determining structural numbers involves utilizing falling weight deflectometer and ground-penetrating radar tests,recording pavement surface deflections,and analyzing recorded deflections by back-calculation manners.This procedure has two drawbacks:falling weight deflectometer and ground-penetrating radar are expensive tests;back-calculation ways has some inherent shortcomings compared to exact methods as they adopt a trial and error approach.In this study,three machine learning methods entitled Gaussian process regression,M5P model tree,and random forest used for the prediction of structural numbers in flexible pavements.Dataset of this paper is related to 759 flexible pavement sections at Semnan and Khuzestan provinces in Iran and includes“structural number”as output and“surface deflections and surface temperature”as inputs.The accuracy of results was examined based on three criteria of R,MAE,and RMSE.Among the methods employed in this paper,random forest is the most accurate as it yields the best values for above criteria(R=0.841,MAE=0.592,and RMSE=0.760).The proposed method does not require to use ground penetrating radar test,which in turn reduce costs and work difficulty.Using machine learning methods instead of back-calculation improves the calculation process quality and accuracy.
