This paper investigates the characteristics of a non-stationary time series, which exists in mechanical fault diagnosis. Combining the characteristics with predictive efficiency, the limitation of the ARIMA model pred...This paper investigates the characteristics of a non-stationary time series, which exists in mechanical fault diagnosis. Combining the characteristics with predictive efficiency, the limitation of the ARIMA model prediction method is analyzed. This model often is applied in the prediction of a non-stationary times series in present. Thus, a wavelet prediction method is introduced to solve non-stationary problems. The Mallat method, often used in signal processing, results form the decimation or the retention of one out of every two samples. Its advantage is that just enough information is kept to allow the exact reconstruction of the input series, but the disadvantage is a time-varying series on line cannot be pursued. Therefore, the authors present another method, à Trous method, which can be applied for recursive prediction in real-time sampling procedure.展开更多
In order to realize mass transfer analysis for microwave hot in-place recycling of asphalt pavements, a volume element is established including asphalt mixtures, liquid water and vapor. A mass transfer control model i...In order to realize mass transfer analysis for microwave hot in-place recycling of asphalt pavements, a volume element is established including asphalt mixtures, liquid water and vapor. A mass transfer control model is built by the theory of multiphysics, phase transformation and diffusion. The model contains continuity equation, energy conservation equation, movement equation and vapor diffusion equation. To gain the solution of the mass transfer model, the formulas are simplified to one-dimensional differential equations. And then a mathematical model of boundary conditions is established. The mass transfer velocity and dissipative energy are obtained in different moisture contents through simulation of asphalt pavements recycling. The result indicates that when initial moisture content is certain, mass transfer velocity is almost uniform in depth direction at the same heating time and enertrv absorbed by water i,~ descendino with denletion of moisture.展开更多
基金Sponsored by the National High Technology Research and Development Program of China (Grant No.2002AA721063).
文摘This paper investigates the characteristics of a non-stationary time series, which exists in mechanical fault diagnosis. Combining the characteristics with predictive efficiency, the limitation of the ARIMA model prediction method is analyzed. This model often is applied in the prediction of a non-stationary times series in present. Thus, a wavelet prediction method is introduced to solve non-stationary problems. The Mallat method, often used in signal processing, results form the decimation or the retention of one out of every two samples. Its advantage is that just enough information is kept to allow the exact reconstruction of the input series, but the disadvantage is a time-varying series on line cannot be pursued. Therefore, the authors present another method, à Trous method, which can be applied for recursive prediction in real-time sampling procedure.
基金Supported by the National Natural Science Foundation of China （51106001） Anhui College Provincial Natural Science Research Project （No. KJ2011B018）
文摘In order to realize mass transfer analysis for microwave hot in-place recycling of asphalt pavements, a volume element is established including asphalt mixtures, liquid water and vapor. A mass transfer control model is built by the theory of multiphysics, phase transformation and diffusion. The model contains continuity equation, energy conservation equation, movement equation and vapor diffusion equation. To gain the solution of the mass transfer model, the formulas are simplified to one-dimensional differential equations. And then a mathematical model of boundary conditions is established. The mass transfer velocity and dissipative energy are obtained in different moisture contents through simulation of asphalt pavements recycling. The result indicates that when initial moisture content is certain, mass transfer velocity is almost uniform in depth direction at the same heating time and enertrv absorbed by water i,~ descendino with denletion of moisture.
