Notice of RetractionEvaluation on the Stability of Rock Mass Deformation Based on Chaotic Muation -RPNN Model
To analysis the stability of rock mass long-term developing deformation,the chaotic muation -RPNN model is built. Combining the chaos theory,the muation theory is introduced, and the stability of rock mass deformation is evaluated by chaotic muation -RPNN model. The lost measured displacement data are interpolated by using the higher order polynomial methos, and the long-term displacement is forecasted,and the stability of rock mass long-term developing deformation is analyzed. Research shows that the strend of predicted displacement is approximately the same as that of measuring displacement,and there is no suddenly dropped or sudden increased phenomena,and the displacement increasing strend of some measuring point remains stable with Lower growth trend, and the deformation of rock mass is strending to be stable.
Long-Term Prediction Model of Rock Mass Displacement Based on Chaotic-Dynamic Time Delay BP Neutral Network
The chaos-dynamic time delay BP neural network model is built to realize long-term prediction of rock mass displacement of large underground grave,and fast analyze long-time stability of surrounding rock through optimized structure of BP neural network coupling with chaotic-dynamic parameters of displacement. Embedding dimension is set as the number of input layer, and predicting feedback mode of neural network is added, and prediction training samples are generated dynamically, so long-term forecasting are enabled. The relative bigger delay time is selected, then time delay between adjacent phase points is when forecasting step is, so the long-time prediction is realized by limited number of forecasting steps. The instances show that computational stability of built prediction model is preferable with faster calculating speed, and prediction precision is all within 10% when predicting step is not more than 5, and the number of forecasting displacements is not more than 10. Terefore the forecasting results are real time and effective, the long-term prediction of rock mass displacement is realized.
Time and Heritage
As a historian studying what can be considered a form of intellectual history, I have slowly come to adopt Michel de Certeau’s observation made at the end of the 1980s that ‘objectifying the past, for the last three centuries, has undoubtedly left unconsidered time within a discipline that has continued to use it as a taxonomic instrument’. To a certain degree, time has become commonplace for the historian who has preserved or instrumentalized it. It is not considered because it is inconceivable, but because we do not think of it or, more simply, we do not think about it. As a historian attempting to pay attention to the time I’m living in, I have thus, like many others, noticed the swift development of the category of the present until it has become obvious that the present is omnipresent. This is what I refer to here as ‘presentism’.