A conflict is an event in which two or more aircraft experience a loss of minimum separation. In this paper, we formulate the problem of solving conflicts arising among several aircraft moving in a shared airspace as ...A conflict is an event in which two or more aircraft experience a loss of minimum separation. In this paper, we formulate the problem of solving conflicts arising among several aircraft moving in a shared airspace as a Constraint Satisfaction Problem (CSP). The constraint satisfaction problem being NP-complete, the algorithms developed to solve it have been of two types: non-systematic and systematic search methods. In this paper, we have considered a breakout algorithm as an example of non-systematic search methods and a backtracking procedure that maintains Arc Consistency (MAC) as an example of systematic search methods. The performance of these algorithms was compared experimentally and the Breakout algorithm is shown to be clearly superior.展开更多
Enterprise Informationization （El） is encountering a large variety of non-systematic risks in demanding and planning, designing and selecting, implementing and controlling, managerial and cultural aspects,due to whi...Enterprise Informationization （El） is encountering a large variety of non-systematic risks in demanding and planning, designing and selecting, implementing and controlling, managerial and cultural aspects,due to which the investment in IT normally cannot simultaneously create the expected commercial values. Through analyzing the factors influencing non-systematic risks of EI, the paper established a risk evaluating index system and accordingly proposed a set of appropriate risk evaluating methodology, with which enterprise can well control informationization risks.展开更多
A variational method based on previous numerical forecasts is developed to estimate and correct non-systematic component of numerical weather forecast error. In the method, it is assumed that the error is linearly dep...A variational method based on previous numerical forecasts is developed to estimate and correct non-systematic component of numerical weather forecast error. In the method, it is assumed that the error is linearly dependent on some combination of the forecast fields, and three types of forecast combination are applied to identifying the forecasting error: 1) the forecasts at the ending time, 2) the combination of initial fields and the forecasts at the ending time, and 3) the combination of the forecasts at the ending time and the tendency of the forecast. The Single Value Decomposition (SVD) of the covariance matrix between the forecast and forecasting error is used to obtain the inverse mapping from flow space to the error space during the training period. The background covariance matrix is hereby reduced to a simple diagonal matrix. The method is tested with a shallow-water equation model by introducing two different model errors. The results of error correction for 6, 24 and 48 h forecasts show that the method is effective for improving the quality of the forecast when the forecasting error obviously exceeds the analysis error and it is optimal when the third type of forecast combinations is applied.展开更多
Due to the limited cognition of meridian structure, the study of the essence of meridian phenomenon is faced with obstruction. This paper aims to expound on the multi-substantial structures of meridians and put forwar...Due to the limited cognition of meridian structure, the study of the essence of meridian phenomenon is faced with obstruction. This paper aims to expound on the multi-substantial structures of meridians and put forward hypothesis on multi-substantial structures of meridians based on embryology.展开更多
文摘A conflict is an event in which two or more aircraft experience a loss of minimum separation. In this paper, we formulate the problem of solving conflicts arising among several aircraft moving in a shared airspace as a Constraint Satisfaction Problem (CSP). The constraint satisfaction problem being NP-complete, the algorithms developed to solve it have been of two types: non-systematic and systematic search methods. In this paper, we have considered a breakout algorithm as an example of non-systematic search methods and a backtracking procedure that maintains Arc Consistency (MAC) as an example of systematic search methods. The performance of these algorithms was compared experimentally and the Breakout algorithm is shown to be clearly superior.
基金Supported by National Natural Science Foundation of China （NSFC） （70302006）
文摘Enterprise Informationization （El） is encountering a large variety of non-systematic risks in demanding and planning, designing and selecting, implementing and controlling, managerial and cultural aspects,due to which the investment in IT normally cannot simultaneously create the expected commercial values. Through analyzing the factors influencing non-systematic risks of EI, the paper established a risk evaluating index system and accordingly proposed a set of appropriate risk evaluating methodology, with which enterprise can well control informationization risks.
基金Supported by National Natural Science Foundation of China (Grant Nos. 40875063 and 40505022)
文摘A variational method based on previous numerical forecasts is developed to estimate and correct non-systematic component of numerical weather forecast error. In the method, it is assumed that the error is linearly dependent on some combination of the forecast fields, and three types of forecast combination are applied to identifying the forecasting error: 1) the forecasts at the ending time, 2) the combination of initial fields and the forecasts at the ending time, and 3) the combination of the forecasts at the ending time and the tendency of the forecast. The Single Value Decomposition (SVD) of the covariance matrix between the forecast and forecasting error is used to obtain the inverse mapping from flow space to the error space during the training period. The background covariance matrix is hereby reduced to a simple diagonal matrix. The method is tested with a shallow-water equation model by introducing two different model errors. The results of error correction for 6, 24 and 48 h forecasts show that the method is effective for improving the quality of the forecast when the forecasting error obviously exceeds the analysis error and it is optimal when the third type of forecast combinations is applied.
文摘Due to the limited cognition of meridian structure, the study of the essence of meridian phenomenon is faced with obstruction. This paper aims to expound on the multi-substantial structures of meridians and put forward hypothesis on multi-substantial structures of meridians based on embryology.
