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A new algorithm for bottom-up saliency estimation is proposed. Based on the sparse coding model, a power spectral filter is proposed to eliminate the second-order residual correlation, which suppresses the global repeated items effectively. In addition, aiming at modeling the mechanism of the human retina prior response to high-contrast stimuli, the effect of color context is considered. Experiments on the three publicly available databases and some psychophysical images show that the proposed model is comparable with the state-of-the-art saliency models, which not only highlights the salient objects in a complex environment but also pops up them uniformly. 相似文献
446.
Guoqi Liu Wengeng Huang Jiancun Gong Hua Shen 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Variability of vertical TEC recorded at Fuzhou (26.1°N, 119.3°E, geomagnetic latitude 14.4°N), Xiamen (24.5°N, 118.1°E, geomagnetic latitude 13.2°N), Nanning (22.8°N, 108.3°E, geomagnetic latitude 11.4°N), China, during the low solar activity in 2006–2007 have been analyzed and discussed. Remarkable seasonal anomaly was found over three stations with the highest value during spring and the lowest value during summer. The relative standard deviation of VTEC is over 20% all the time, with steady and smooth variation during daytime while it has a large fluctuation during nighttime. The biggest correlation coefficient was found in the VTEC-sunspot pair with a value of over 0.5. It seems that solar activity has a better correlation ship than geomagnetic activity with the variation of VTEC and better correlations are found with more long-term data when comparing our previous study. The results of comparing observation with model prediction in three sites reveal again that the SPIM model overestimates the measured VTEC in the low latitude area. 相似文献
447.
Bofeng Li Yunzhong Shen Xingfu Zhang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Three frequency GNSS (Global Navigation Satellite Systems) signals will be fully accessible in the near future. It is theoretically well-understood that the GNSS navigation performance could be improved with introduction of the third frequency signals. However it remains unclear what numerical improvements can be achieved in the varying navigation scenarios. In this paper, we numerically demonstrate the superior navigation prospect of three frequency GNSS compared to dual-frequency case. Since the third frequency pseudorange is not fully accessible at current stage, a semi-simulation method is firstly introduced to generate the third frequency pseudorange based on the dual-frequency GPS pseudorange and phase measurements. Then the three frequency navigation precision, availability and reliability are examined, compared with their dual-frequency counterparts in varying simulated navigation scenarios. The results show that with three frequency GNSS signals the navigation precision can be improved by 10% in both horizontal and vertical components. More promisingly, the availability of navigation solutions is significantly improved (even by 50% for some scenarios) with higher reliability. 相似文献
448.
RFNN control for PMLSM drive via backstepping technique 总被引:2,自引:0,他引:2
Faa-Jeng Lin Po-Hung Shen Rong-Fong Fung 《IEEE transactions on aerospace and electronic systems》2005,41(2):620-644
A robust fuzzy neural network (RFNN) control system is proposed in this study to control the position of the mover of a permanent magnet linear synchronous motor (PMLSM) drive system to track periodic reference trajectories. First, an ideal feedback linearization control law is designed based on the backstepping technique. Then, a fuzzy neural network (FNN) controller is designed to be the main tracking controller of the proposed RFNN control system to mimic an ideal feedback linearization control law, and a robust controller is proposed to confront the shortcoming of the FNN controller. Moreover, to relax the requirement for the bound of uncertainty term, which comprises a minimum approximation error, optimal parameter vectors and higher order terms in Taylor series, an adaptive bound estimation is investigated where a simple adaptive algorithm is utilized to estimate the bound of uncertainty. Furthermore, the simulated and experimental results due to periodic reference trajectories demonstrate that the dynamic behaviors of the proposed control systems are robust with regard to uncertainties. 相似文献
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介绍了核工业系统内各检测试验中心在计量认证及复查评审中所开展的工作 ,以及由此带来的变化 相似文献