Feature reduction is a key process in pattern recognition. This paper deals with the feature reduction methods for a time-shift invariant feature, power spectrum, in Radar Automatic Target Recognition (RATR) using Hig...Feature reduction is a key process in pattern recognition. This paper deals with the feature reduction methods for a time-shift invariant feature, power spectrum, in Radar Automatic Target Recognition (RATR) using High-Resolution Range Profiles (HRRPs). Several existing feature reduction methods in pattern recognition are analyzed, and a weighted feature reduction method based on Fisher's Discriminant Ratio (FDR) is proposed in this paper. According to the characteristics of radar HRRP target recognition, this proposed method searches the optimal weight vector for power spectra of HRRPs by means of an iterative algorithm, and thus reduces feature dimensionality. Compared with the method of using raw power spectra and some existing feature reduction methods, the weighted feature reduction method can not only reduce feature dimensionality, but also improve recognition performance with low computation complexity. In the recognition experiments based on measured data, the proposed method is robust to different test data and achieves good recognition results.展开更多
In actual implementation of spectrum sharing systems, due to the selfishness of primary users, primary users often refuse the access of secondary users to their licensed spectrum bands even if the access of secondary ...In actual implementation of spectrum sharing systems, due to the selfishness of primary users, primary users often refuse the access of secondary users to their licensed spectrum bands even if the access of secondary users doesn＇t affect their transmission. Aimed at the selfishness problem of primary users, a seller＇s market trading mechanism is introduced which can not only stimulate primary users to tolerate larger interference power but also give the primary users an appropriate compensation at the same time, and which has very important practical significance. Based on the mechanism, the achievable maximal gross profit of secondary users and their optimal power allocation scheme in the Rayleigh fading environment are derived, and the interference price of primary users and the average revenue of secondary users＇ impact on them are also studied. Numerical calculation results are conducted to verify our theoretical results.展开更多
This paper has an objective to show a developed quantitative criterion,based in two mathematical variables that explicit the deviation degree of a normal situation,applying simultaneously data from terminal impedances...This paper has an objective to show a developed quantitative criterion,based in two mathematical variables that explicit the deviation degree of a normal situation,applying simultaneously data from terminal impedances and frequency response.Based in more than 100-measured equipment,of different applications(step-up transformer,transmission transformer,etc.,),for a period of 10 years,the work presents some examples of practical application of this methodology in Brazilian Electrical System.展开更多
The runoff in alpine river basins where the runoff is formed in nearby mountainous areas is mainly affected by temperature and precipitation. Based on observed annual mean temperature, annual precipitation, and runoff...The runoff in alpine river basins where the runoff is formed in nearby mountainous areas is mainly affected by temperature and precipitation. Based on observed annual mean temperature, annual precipitation, and runoff time-series datasets during 1958-2012 within the Kaidu River Basin, the synchronism of runoff response to climate change was analyzed and iden- tified by applying several classic methods, including standardization methods, Kendall＇s W test, the sequential version of the Mann-Kendall test, wavelet power spectrum analysis, and the rescaled range （R/S） approach. The concordance of the nonlinear trend variations of the annual mean temperature, annual precipitation, and runoff was tested significantly at the 0.05 level by Kendall＇s W method. The sequential version of the Mann-Kendall test revealed that abrupt changes in annual runoff were synchronous with those of annual mean temperature. The periodic characteristics of annual runoff were mainly consistent with annual precipitation, having synchronous 3-year significant periods and the same 6-year, 10-year, and 38-year quasi-periodicities. While the periodic characteristics of annual runoff in the Kaidu River Basin tracked well with those of annual precipitation, the abrupt changes in annual runoff were synchronous with the annual mean temperature, which directly drives glacier- and snow-melt processes. R/S analysis indicated that the annual mean temperature, annual precipitation, and runoff will continue to increase and remain synchronously persistent in the future. This work can improve the understanding of runoff response to regional climate change to provide a viable reference in the management of water resources in the Kaidu River Basin, a regional sustainable socio-economie development.展开更多
基金Partially supported by the National Natural Science Foundation of China (No.60302009)the National Defense Advanced Research Foundation of China (No.413070501).
文摘Feature reduction is a key process in pattern recognition. This paper deals with the feature reduction methods for a time-shift invariant feature, power spectrum, in Radar Automatic Target Recognition (RATR) using High-Resolution Range Profiles (HRRPs). Several existing feature reduction methods in pattern recognition are analyzed, and a weighted feature reduction method based on Fisher's Discriminant Ratio (FDR) is proposed in this paper. According to the characteristics of radar HRRP target recognition, this proposed method searches the optimal weight vector for power spectra of HRRPs by means of an iterative algorithm, and thus reduces feature dimensionality. Compared with the method of using raw power spectra and some existing feature reduction methods, the weighted feature reduction method can not only reduce feature dimensionality, but also improve recognition performance with low computation complexity. In the recognition experiments based on measured data, the proposed method is robust to different test data and achieves good recognition results.
基金Supported by the National Basic Research Program of China （2007CB307104）, the National Natural Science Foundation of China （60973160）, and the Intematiortal Scientific and Technological Cooperation Program （No. $2010GR0902）.
文摘In actual implementation of spectrum sharing systems, due to the selfishness of primary users, primary users often refuse the access of secondary users to their licensed spectrum bands even if the access of secondary users doesn＇t affect their transmission. Aimed at the selfishness problem of primary users, a seller＇s market trading mechanism is introduced which can not only stimulate primary users to tolerate larger interference power but also give the primary users an appropriate compensation at the same time, and which has very important practical significance. Based on the mechanism, the achievable maximal gross profit of secondary users and their optimal power allocation scheme in the Rayleigh fading environment are derived, and the interference price of primary users and the average revenue of secondary users＇ impact on them are also studied. Numerical calculation results are conducted to verify our theoretical results.
文摘This paper has an objective to show a developed quantitative criterion,based in two mathematical variables that explicit the deviation degree of a normal situation,applying simultaneously data from terminal impedances and frequency response.Based in more than 100-measured equipment,of different applications(step-up transformer,transmission transformer,etc.,),for a period of 10 years,the work presents some examples of practical application of this methodology in Brazilian Electrical System.
基金financially supported by the National Natural Science Foundation of China(No.41471031)
文摘The runoff in alpine river basins where the runoff is formed in nearby mountainous areas is mainly affected by temperature and precipitation. Based on observed annual mean temperature, annual precipitation, and runoff time-series datasets during 1958-2012 within the Kaidu River Basin, the synchronism of runoff response to climate change was analyzed and iden- tified by applying several classic methods, including standardization methods, Kendall＇s W test, the sequential version of the Mann-Kendall test, wavelet power spectrum analysis, and the rescaled range （R/S） approach. The concordance of the nonlinear trend variations of the annual mean temperature, annual precipitation, and runoff was tested significantly at the 0.05 level by Kendall＇s W method. The sequential version of the Mann-Kendall test revealed that abrupt changes in annual runoff were synchronous with those of annual mean temperature. The periodic characteristics of annual runoff were mainly consistent with annual precipitation, having synchronous 3-year significant periods and the same 6-year, 10-year, and 38-year quasi-periodicities. While the periodic characteristics of annual runoff in the Kaidu River Basin tracked well with those of annual precipitation, the abrupt changes in annual runoff were synchronous with the annual mean temperature, which directly drives glacier- and snow-melt processes. R/S analysis indicated that the annual mean temperature, annual precipitation, and runoff will continue to increase and remain synchronously persistent in the future. This work can improve the understanding of runoff response to regional climate change to provide a viable reference in the management of water resources in the Kaidu River Basin, a regional sustainable socio-economie development.
