How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the...How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between the large aircraft component's ball-head and the localizer's ball-socket. The localizer is driven to achieve a new position by compensation. Relatively, a support revising algorithm is proposed. The localizer's ball-socket approaches the ball-head based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage's ball-head into a localizer's ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied widely in the modern aircraft industry.展开更多
The accurately targeted poverty alleviation has gradually become one of the important research directions in the field of poverty research. The existing foreign and domestic studies concerning about the accurately tar...The accurately targeted poverty alleviation has gradually become one of the important research directions in the field of poverty research. The existing foreign and domestic studies concerning about the accurately targeted poverty alleviation are few and mainly focus on the aspects such as poverty object recognition, target for poverty alleviation, and fund embarking; a complete system has not yet been formed for the relevant studies. On the basis of analyzing and reviewing relevant studies on the accurately targeted poverty alleviation at home and abroad, a further research direction for the accurately targeted poverty alleviation is proposed in this paper.展开更多
Accurate fault prediction can obviously reduce cost and decrease the probability of accidents so as to improve the performance of the system testing and maintenance.Traditional fault prediction methods are always offl...Accurate fault prediction can obviously reduce cost and decrease the probability of accidents so as to improve the performance of the system testing and maintenance.Traditional fault prediction methods are always offline that are not suitable for online and real-time processing.For the complicated nonlinear and non-stationary time series,it is hard to achieve exact predicting result with single models such as support vector regression(SVR),artifieial neural network(ANN),and autoregressive moving average(ARMA).Combined with the accurate online support vector regression(AOSVR)algorithm and ARMA model,a new online approach is presented to forecast fault with time series prediction.The fault trend feature can be extracted by the AOSVR with global kernel for general fault modes.Moreover,its prediction residual that represents the local high-frequency components is synchronously revised and compensated by the sliding time window ARMA model.Fault prediction with combined AOSVR and ARMA can be realized better than with the single one.Experiments on Tennessee Eastman process fault data show the new method is practical and effective.展开更多
Teachers are the primary resource of education and an important guarantee for building a high-quality education system.Teaching research is an effective way for teacher professional development.This paper focuses on p...Teachers are the primary resource of education and an important guarantee for building a high-quality education system.Teaching research is an effective way for teacher professional development.This paper focuses on problems of the failure of traditional teaching research models,unbalanced supply,and inaccurate support,with the core goal of realizing the clustered,synergistic,and high-quality development of teachers,and builds a new form model of three integrations,one focus,and N innovations for regional informatization teaching research with innovative characteristics,a dual coordination mechanism for the clustered high-quality development of teachers,and an accurate support strategy for the comprehensive literacy of teacher informatization teaching research.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 50905161)the Natural Science Foundation of Zhejiang Province (No. Y1110339)the Fundamental Research Funds for the Central Universities of China (No. 2010QNA4024)
文摘How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between the large aircraft component's ball-head and the localizer's ball-socket. The localizer is driven to achieve a new position by compensation. Relatively, a support revising algorithm is proposed. The localizer's ball-socket approaches the ball-head based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage's ball-head into a localizer's ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied widely in the modern aircraft industry.
文摘The accurately targeted poverty alleviation has gradually become one of the important research directions in the field of poverty research. The existing foreign and domestic studies concerning about the accurately targeted poverty alleviation are few and mainly focus on the aspects such as poverty object recognition, target for poverty alleviation, and fund embarking; a complete system has not yet been formed for the relevant studies. On the basis of analyzing and reviewing relevant studies on the accurately targeted poverty alleviation at home and abroad, a further research direction for the accurately targeted poverty alleviation is proposed in this paper.
文摘Accurate fault prediction can obviously reduce cost and decrease the probability of accidents so as to improve the performance of the system testing and maintenance.Traditional fault prediction methods are always offline that are not suitable for online and real-time processing.For the complicated nonlinear and non-stationary time series,it is hard to achieve exact predicting result with single models such as support vector regression(SVR),artifieial neural network(ANN),and autoregressive moving average(ARMA).Combined with the accurate online support vector regression(AOSVR)algorithm and ARMA model,a new online approach is presented to forecast fault with time series prediction.The fault trend feature can be extracted by the AOSVR with global kernel for general fault modes.Moreover,its prediction residual that represents the local high-frequency components is synchronously revised and compensated by the sliding time window ARMA model.Fault prediction with combined AOSVR and ARMA can be realized better than with the single one.Experiments on Tennessee Eastman process fault data show the new method is practical and effective.
文摘Teachers are the primary resource of education and an important guarantee for building a high-quality education system.Teaching research is an effective way for teacher professional development.This paper focuses on problems of the failure of traditional teaching research models,unbalanced supply,and inaccurate support,with the core goal of realizing the clustered,synergistic,and high-quality development of teachers,and builds a new form model of three integrations,one focus,and N innovations for regional informatization teaching research with innovative characteristics,a dual coordination mechanism for the clustered high-quality development of teachers,and an accurate support strategy for the comprehensive literacy of teacher informatization teaching research.
