A new geometric modeling approach is introduced in this paper.First the principle of modeling of 3D pipe network is discussed in detail.Then the procedures of implementing pipe network visualization and system functio...A new geometric modeling approach is introduced in this paper.First the principle of modeling of 3D pipe network is discussed in detail.Then the procedures of implementing pipe network visualization and system functions are presented.Last,several efficient methods for speeding up display of graphics are introduced.The new geometric modeling approach offers to people a new way to solve 3D visualization of complex urban pipe network.展开更多
With the development of information networks, the problem of power security has increasingly caused many attention of people, but the simple power security defense system has been difficult to meet the current complex...With the development of information networks, the problem of power security has increasingly caused many attention of people, but the simple power security defense system has been difficult to meet the current complex network environment. Aiming at this situation, by using the method of T-S fuzzy neural network model to analyze the characteristics of the data transmission in network, it has obtained corresponding threat information. By processing these threat information, it completes the construction of three-dimensional power security defense system. The paper carries on the corresponding data training methods by using T-shirt model fuzzy neural network, which has certain reference significance for the data analysis of other similar fields. At the same time, the study of building on the three-dimensional power security defense system aims to provide a theoretical reference for solving the security defense of the current complex network environment.展开更多
Due to the excellent dynamic performance,the Finite Control Set Model Predictive Control has been widely used in various types of converters.However,when Finite Control Set Model Predictive Control is adopted,the swit...Due to the excellent dynamic performance,the Finite Control Set Model Predictive Control has been widely used in various types of converters.However,when Finite Control Set Model Predictive Control is adopted,the switching frequency of converters varies significantly with system operating conditions.Consequently,constant-frequency predictive control strategy has been proposed.Two active voltage vectors and a zero voltage vector are selected within each sampling period.The action time sequence is then calculated.Due to the unsymmetrical distribution of current variation rates around zero,the calculated value of the voltage-vector action time will turn up negative.According to common sense,the voltage-vector action time is greater than or equal to zero.The action time is normally forced to zero whenever a negative value is predicted,resulting in the control failure and performance deterioration.To solve this problem,this paper proposes modified strategy.The modified strategy examines the action time calculated out.When negative action time comes out,the modified strategy reselects the active voltage vector accordingly,instead of forcing the action time to be zero.Optimized action time sequence is further determined by minimizing the cost function.The effectiveness of the modified strategy is clearly verified by experimental tests,and analytical remarks are all founded in practical results.展开更多
文摘A new geometric modeling approach is introduced in this paper.First the principle of modeling of 3D pipe network is discussed in detail.Then the procedures of implementing pipe network visualization and system functions are presented.Last,several efficient methods for speeding up display of graphics are introduced.The new geometric modeling approach offers to people a new way to solve 3D visualization of complex urban pipe network.
文摘With the development of information networks, the problem of power security has increasingly caused many attention of people, but the simple power security defense system has been difficult to meet the current complex network environment. Aiming at this situation, by using the method of T-S fuzzy neural network model to analyze the characteristics of the data transmission in network, it has obtained corresponding threat information. By processing these threat information, it completes the construction of three-dimensional power security defense system. The paper carries on the corresponding data training methods by using T-shirt model fuzzy neural network, which has certain reference significance for the data analysis of other similar fields. At the same time, the study of building on the three-dimensional power security defense system aims to provide a theoretical reference for solving the security defense of the current complex network environment.
基金supported in part by the National Key Basic Research Program of China ("973" Program) (Grant No. 2013CB035602)the National Natural Science Foundation of China (Grant No. 51107084)the Doctoral Program of Higher Education of China(Grant No. 20100032120081)
文摘Due to the excellent dynamic performance,the Finite Control Set Model Predictive Control has been widely used in various types of converters.However,when Finite Control Set Model Predictive Control is adopted,the switching frequency of converters varies significantly with system operating conditions.Consequently,constant-frequency predictive control strategy has been proposed.Two active voltage vectors and a zero voltage vector are selected within each sampling period.The action time sequence is then calculated.Due to the unsymmetrical distribution of current variation rates around zero,the calculated value of the voltage-vector action time will turn up negative.According to common sense,the voltage-vector action time is greater than or equal to zero.The action time is normally forced to zero whenever a negative value is predicted,resulting in the control failure and performance deterioration.To solve this problem,this paper proposes modified strategy.The modified strategy examines the action time calculated out.When negative action time comes out,the modified strategy reselects the active voltage vector accordingly,instead of forcing the action time to be zero.Optimized action time sequence is further determined by minimizing the cost function.The effectiveness of the modified strategy is clearly verified by experimental tests,and analytical remarks are all founded in practical results.
