In the reconstructed phase space,based on the Karhunen-Lo(?)ve transformation(KLT),the new local linear prediction method is proposed to predict chaotic time series.A noise-free chaotic time series and a noise added chaotic time series are analyzed.The simulation results show that the KLT-based local linear prediction method can effectively make one-step and multi-step prediction for chaotic time series,and the one-step and multi-step prediction accuracies of the KLT-based local linear prediction method are superior to that of the traditional local linear prediction.
In this paper we apply the nonlinear time series analysis method to small-time scale traffic measurement data. The prediction-based method is used to determine the embedding dimension of the traffic data. Based on the reconstructed phase space, the local support vector machine prediction method is used to predict the traffic measurement data, and the BIC-based neighbouring point selection method is used to choose the number of the nearest neighbouring points for the local support vector machine regression model. The experimental results show that the local support vector machine prediction method whose neighbouring points are optimized can effectively predict the small-time scale traffic measurement data and can reproduce the statistical features of real traffic measurements.
The early-age hydration of Portland cement paste has an important impact on the formation of microstructure and development of strength.However,manual derivation of hydration kinetic equation is very difficult because there are multi-phased,multi-sized and interrelated complex chemical and physical reactions during cement hydration.In this paper,early-age hydration kinetic equation is reversely extracted automatically from the observed time series of hydration degree of Portland cement using evolutionary computation method that combines gene expression programming and particle swarm optimization algorithms.In order to reduce the computing time,GPUs are used for acceleration in parallel.Studies have shown that according to the extracted kinetic equation,simulation curve of early-age hydration is in good accordance with the observed experimental data.Furthermore,this equation still has a good generalization ability even changing chemical composition,particle size and curing conditions.
WANG Lin1,YANG Bo2,ZHAO XiuYang1,2,CHEN YueHui2 & CHANG Jun3 1 School of Computer Science and Technology,Shandong University,Jinan 250101,China
