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Studying fish recognition has important realistic and theoretical significance to aquaculture and marine biology. Fish recognition is challenging problem because of distortion, overlap and occlusion of digital images. Previous researchers have done a lot of work on fish recognition, but the classification accuracy may be not high enough. Classification and recognition methods based on convolutional...
The multilayer perceptrons (MLPs) have been widely used in many communication applications, however, the learning process of the multilayer perceptrons often becomes very slow, which is due to the existence of the singularities in the parameter space. As the singularities significantly affect the learning dynamics of MLPs, the standard gradient descent method is not Fisher efficient. In order to overcome...
Efficient condition monitoring and fault diagnosis is an essential task to ensure the generation performance and reliability of photovoltaic (PV) systems. This paper proposes an online algorithm to diagnose faults of PV module based on multi-class support vector machine (M-SVM). The simulation models of the photovoltaic module are implemented and the output power generation characteristics of PV modules...
Smart materials actuated devices have been attracting tremendous attentions for decades, especially nowadays. Smart material actuators have been prevalently utilized in the fields such as soft robots and nano-engineering for their outstanding merits such as flexibility and ultrahigh spatial resolution. Although, usage of these smart material actuators can facilitate transmission systems design, problems...
This paper presents an observer-based motion control scheme for a single mobile robot to track and monitor a dynamic pollutant plume propagation in m-dimensional space. The spatiotemporal dynamics of the pollutant plume is modeled by an advection-diffusion partial differential equation (PDE), and the plume front is described by a level set with a prespecified threshold value. In the suggested control...
In the DC distributed power system of the more electric aircraft (MEA), it is necessary to have a LC filter in the input of boost converter due to electromagnetic interference (EMI) and sharp input impulse voltage. Whereas, the interaction between boost converter and poorly damping filter may cause instability throughout the system., The problem may be solved by adding resistor or increasing capacitance,...
In recent type tests, a 252kV SF6 self-blast circuit breaker re-ignites several times after interruption. In order to solve this problem, through CFD simulation of the gas flow field in the interrupter on load, the pressure, temperature and velocity after current zero are analyzed carefully. The conclusion is that, due to the upstream pressure decreased quickly after current zero and will lower than...
Considering the factors of skin effect, contact resistance, natural convection and radiation, etc., Multi-physics field coupling simulation model for 3D electromagnetic, flow and temperature field of AC high voltage GIS busbar is established, power loss, temperature and gas flow distribution is calculated and analyzed, the distribution of the temperature gradient is obtained; Based on the proposed...
Recently, fault indicators with communication function have been increasingly used in fault diagnosis of distribution networks. In this paper, an objective function which considers the reliability index of the distribution network and economic factors synthetically has been proposed for optimal placement of fault indicators in distribution networks, and binary particle swarm optimization algorithm...
In order to improve the breaking performance of the ultra-high voltage SF6 circuit breaker, an optimal design scheme for increasing the straight line length of the nozzle throat is proposed. Based on the numerical simulation of the gas flow field in the optimized structure of the interrupter, the influence of the straight line length of the nozzle throat on the breaking performance of the circuit...
In this paper, we consider an optimal parameter and state estimation problem arising in an one-dimensional (1D) magnetohydrodynamic (MHD) flow system, whose dynamics can be modeled by a coupled partial differential equations (PDEs). In this model, the coefficients of the Reynolds number and initial conditions as well as state variables are supposed to be unknown and need to be estimated. An adjoint-based...
In this paper, we consider the problem of attitude control for flexible satellites based on the quaternion model with unknown bounded external disturbance. A sliding mode control law is designed to attenuate the effects of the disturbance for the closed-loop system. In addition, an observer-based sliding mode control law is proposed when the flexible modal variables of the flexible satellites are...
This paper presents a particle swarm optimization (PSO) timing scheme for a single intersection and a bidirectional green wave coordination control scheme for an artery. The timing strategy is proposed to reduce vehicle delays based on Akcelik delay model at the intersection via adaptive particle swarm optimization (APSO) algorithm. The coordination control scheme is designed to make as many vehicles...
In order to realize the high dynamic performance of induction motor, a passive speed control scheme of induction motor based on full-order state observer and speed adaptive estimation is proposed for the non-linear nature of the motor. With the analysis of the passive of induction motor and the relationship between passive and stability, a scheme of asymptotic stability torque tracking controller...
The focal track sensor is a monocular and computationally efficient depth sensor that is based on defocus controlled by a liquid membrane lens. It synchronizes small lens oscillations with a photosensor to produce real-time depth maps by means of differential defocus, and it couples these oscillations with bigger lens deformations that adapt the defocus working range to track objects over large axial...
This paper presents an analytic, numerical and experimental study of air damping behavior of lateral-axis vibratory wheel gyroscopes (VWG) in vacuum range of 0.008Pa to 10Pa. An analytic model is proposed for slide film damping in drive mode, and a Reynolds equation solved by a finite-difference method is employed for squeeze film damping in sense mode. The developed models are verified by experiment...
This paper presents a new two-step method to estimate the ratios of the moment of inertia, the direction of the angular momentum in inertial frame, the attitude and angular velocity of the space noncooperative tumbling target, based on the measured relative attitude from the servicing spacecraft. At the beginning, the target's body frame should be determined based on its geometrical shapes. In the...
In this paper, the output tracking of time-varying linear system is investigated with pseudo division-by-zero phenomenon illustrated. We only use Zhang dynamics (ZD) to design a ZD tracking controller, which is easier than using Zhang-gradient (ZG) method. The purpose of output tracking control for the considered time-varying linear system is to make the actual output track the desired output with...
A control strategy to manage the circulating current content in a Modular Multilevel Converter in direct AC-AC topology is proposed in this article. The converter is connected in three-phase YDY configuration which forms a closed delta path for free current circulation while keeping outsider waveforms with low THD content. Circulating current correction becomes necessary face to any kind of unbalance...
Bioelectrical impedance technology is considered to be a noninvasive method of measuring heart function. Feature points extraction of impedance cardiography (ICG) signal is vital to cardiovascular disease diagnosis, and feature points extraction has curative value after operation. In this paper, the new algorithm combined with the wavelet technology to extract feature points accurately. Feature points...
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