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For the image of present surface defects in steel plates, a surface defect detection method based on human visual attention mechanism is proposed. Based on the physiological structure and function of human visual system, this paper establishes a steel surface defect detection model via Gaussian filter, Gabor filter and the calculation such as cross-scale reduction, cross-scale addition and normalization,...
This paper makes a research about the vibration damping of a flexible riser system. The partial-ordinary differential equations can be used to describe the riser system. Through the fusion of the boundary control and backstepping technique, a control strategy is proposed for suppressing riser's vibration and globally stabilizing the riser system at its equilibrium position, an auxiliary system is...
An adaptive boundary controller is developed in this article for minimizing the vibration displacement of a flexible riser. The dynamics of riser system is represented by partial-ordinary differential equations. Through combining boundary control, adaptive technique with backstepping technique, an adaptive boundary controller is given for realizing vibration restraint for the riser system, where an...
This article presents a boundary control for the vibration reduction of an axially moving belt with high acceleration/deceleration in the presence of unknown disturbances. The nonhomogeneous infinite-dimensional model of the belt system is obtained via the extended Hamilton's principle. In an appropriate mathematical manner, the Lyapunov's direct method is adopted to construct a control law for the...
In this paper, the modeling and vibration control problem of an axially moving belt with high acceleration/deceleration under unknown disturbances are addressed. The dynamic model of the belt system is represented by a nonhomogeneous hyperbolic partial differential equation and two ordinary differential equations. Boundary control with disturbance adaption is developed to stabilize the transverse...
In this paper, output feedback boundary control of a flexible marine riser coupled with the internal fluid dynamics is investigated. By merging Lyapunov's direct method, boundary control technique and high-gain observers, an output feedback boundary control with disturbance observer is proposed to suppress the riser's vibration and deal with the effects of the external environment disturbance. The...
Commutation failure is a serious malfunction in high-voltage direct current (HVdc) converters and is mainly caused by ac side faults, where the change of dc current during fault conditions should be given adequate attention. Employing superconducting fault current limiters (SFCLs) for an HVdc system can suppress its dc fault current’s amplitude and maintain a small rate of the dc current change, which...
A growth equation of the stand topping mean height was created by using artificial neural network modeling technology, in Masson pine planted forest. Then, a site index model was created with the created equation as the directed equation, and the site index curved shape was drawn with the method of index level adjustment. Finally, the table of site index was worked out. The model structure is 1∶3∶1,...
Diameter distribution is used to predict stand stock, timber volume and stand yield in most forest management. In the paper, opulus shelterbelts in Boai County were analyzed. A model to predict stand diameter distribution was constructed with artificial neural network(ANN) approach by using the average stand diameter, the coefficient of variation of diameter as well as relative diameter as input variables,...
Interferometric baseline plays a very important role in InSAR data processing, and it will directly affect the accuracy of interferometric result. In this article, three classical baseline estimation methods were described. By comparing and combining three methods, a new baseline estimation method and its flow were listed. RADARSAT-2 satellite image data and grid digital elevation model ASTER GDEM...
This paper proposed a novel Current Control based modular multilevel Voltage-Source Converter (CCVSC) topology suitable for different rates of voltage application, especially for the interface of renewable power sources with the main gird and power transmission and distribution usage. The fundamental concept and the applied control scheme are introduced. The unbalanced energy mitigation function of...
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