Gui Weihua

Medical Images Edge Detection Based on Mathematical Morphology

Medical images edge detection is an important work for object recognition of the human organs and it is an important pre-processing step in medical image segmentation and 3D reconstruction. Conventionally, edge is detected according to some early brought forward algorithms such as gradient-based algorithm and template-based algorithm, but they are not so good for noise medical image edge detection. In this paper, basic mathematical morphological theory and operations are introduced at first, and then a novel mathematical morphological edge detection algorithm is proposed to detect the edge of lungs CT image with salt-and-pepper noise. The experimental results show that the proposed algorithm is more efficient for medical image denoising and edge detection than the usually used template-based edge detection algorithms and general morphological edge detection algorithms

Adaptive PCA based fault diagnosis scheme in imperial smelting process

In this paper, an adaptive fault detection scheme based on a recursive principal component analysis (PCA) is proposed to deal with the problem of false alarm due to normal process changes in real process. Our further study is also dedicated to develop a fault isolation approach based on Generalized Likelihood Ratio (GLR) test and Singular Value Decomposition (SVD) which is one of general techniques of PCA, on which the off-set and scaling fault can be easily isolated with explicit off-set fault direction and scaling fault classification. The identification of off-set and scaling fault is also applied. The complete scheme of PCA-based fault diagnosis procedure is proposed. The proposed scheme is first applied to Imperial Smelting Process, and the results show that the proposed strategies can be able to mitigate false alarms and isolate faults efficiently.

Treenet:A Web Services Composition Model Based on Spanning tree

Recently, Web service composition based on the Service Overlay Network has drawn much research attention. In this paper, we present a composition model capable of composing Web services across wide area networks with the service composition based on interface idea integrated with Peer to Peer technologies. It forms a novel Web Services Composition Overlay Network (WSCON) with Peer to Peer technologies, then associate nodes in the same Web services composition domain to form the Web Services Composition Network, according to domain ontology and its reasoning ability. Web service discovery and composition entry are performed through Distributed Hash Table (DHT). We have conducted extensive experiments using large-scale simulations. The experiment results show the advantages of our model: supporting Web service composition based on QoS, high composition success rate, fast service distribution, discovery and composition, and tolerant to dynamic service component node arrivals and departures.

Research on Energy Hole Problem for Wireless Sensor Networks Based on Alternation between Dormancy and Work

This paper theoretically proposes a more accurate analytical method for avoiding energy hole in wireless sensor networks with nonuniform node distribution. Based on the typical energy consumption model of wireless sensor networks, we obtain the relationship of the densities of sensor nodes in different regions of network through rigorous mathematical analysis, and prove that if the densities of sensor nodes working at the same time are, the entire work can achieve uniform energy consumption by making the sensor nodes whose density is greater than alternate between dormancy and work. Through theoretical analysis and numerical simulation, we obtain the following conclusions: 1) Under the circumstance that the parameters of network do not change, the network lifetime can increase several times by selecting appropriate transmission radius of sensor node. 2) To achieve uniform energy consumption of network, the densities of sensor nodes whose distances from the base station are different should be different. Even if the sensor nodes were in the same circular ring, the densities of sensor nodes in different places should not the same. 3) Through nonuniform node distribution and alternation between dormancy and work, the efficiency of network can increase several times and the residual energy of network is nearly zero when the network lifetime ends. Therefore, our research can give a significant guidance on the optimization of wireless sensor networks.

An integrated modeling method for prediction of sulfur content in agglomerate

Based on the idea of fusing modeling, an integrated prediction model for sintering process was proposed. A framework for sulfur content prediction was established, which integrated multi modeling ways together, including mathematical model combined with neural network(NN), rule model based on empirical knowledge and modelchoosing coordinator. Via metallurgic mechanism analysis and material balance computation, a mathematical model calculated the sulfur content in agglomerate by the material balance equation with some parameters predicted by NN method. In the other model, the relationship between sulfur content and key factors was described in the form of expert rules. The model-choosing coordinator based on fuzzy logic was introduced to decide the weight of result of each model according to process conditions. The model was tested by industrial application data and produced a relatively satisfactory prediction error. The model also preferably reflected the varying tendency of sulfur content in agglomerate as the evidence of its prediction performance.

Robust decentralized H ∞ control of multi-channel systems with norm-bounded parametric uncertainties

Abstract A robust decentralized H∞ control problem for uncertain multi-channel systems is considered. The uncertainties are assumed to be time-invariant, norm-bounded, and exist in both the system and control input matrices. The dynamic output feedback is mainly dealt with. A necessary and sufficient condition for the uncertain multi-channel system to be stabilized robustly with a specified disturbance attenuation level is derived based on the bounded real lemma, which is reduced to a feasibility problem of a nonlinear matrix inequality (NMI). A two-stage homotopy method is used to solve the NMI iteratively. First, a decentralized controller for the nominal system with no uncertainty is computed by imposing structural constraints on the coefficient matrices of the controller gradually. Then the decentralized controller is modified, again gradually, to cope with the uncertainties. On each stage, a variable is fixed alternately at the iterations to reduce the NMI to a linear matrix inequality (LMI). A given example shows the efficiency of this method.

Application of Communication Optimization Strategy Based on Cascade PLC MODBUS in Fire Water System of Hydropower Station

As to the bad real-time problem of traditional communication scheme that is one master station and more slave stations’ MODBUS communication in fire water system of hydropower station, in this paper, a connection scheme of a cascade PLC communication was proposed to solve the defects of decreasing transmission speed because of long distance in communication. The communication software of PLC was also optimized to reduce the cycle treatment time of PLC CPU, and greatly improve the communication efficiency and response speed. Practice shows that this scheme has high reference value and be worth to extend in the field of industrial control which use PLC MODBUS to communicate between one master station and more slave stations.

Improved PSO algorithm and its application

The mechanism of particle swarm optimization algorithm is studied, and one can draw the conclusion that the best particle found by the swarm falling into local minima is one of the main reasons for premature convergence. Therefore, an improved particle swarm optimization algorithm is proposed. This algorithm selects the best particle with roulette wheel selection method, so premature converging to local optima is avoided. At last, the improved particle swarm optimization algorithm is applied to optimization of time-sharing power supply for zinc electrolytic process. Simulation and practical results show that the global search ability of IPSO is improved greatly and optimization of time-sharing power supply for zinc electrolytic process can bring about outstanding economic benefit for plant.

Decentralized H∞ state feedback control for large-scale interconnected uncertain systems with multiple delays

Decentralized H∞ control was studied for a class of interconnected uncertain systems with multiple delays in the state and control and time varying but norm-bounded parametric uncertainties. A sufficient condition which makes the closed-loop system decentralized asymptotically stable with H∞ performance was derived based on Lyapunov stability theorem. This condition is expressed as the solvability problem of linear matrix inequalities. The method overcomes the limitations of the existing algebraic Riccati equation method. Finally, a numerical example was given to demonstrate the design procedure for the decentralized H∞ state feedback controller.

Stability Analysis and Design of Adaptive Observer Based on Speed Sensorless Induction Motor

By analyzing the existence of unstable regions of the present adaptive observer using pole-placement technique in regenerating mode at low speeds, conditions that ensure the adaptive observer stability at full speed regions are got. An improved speed adaptive law and a novel method to choose the gain of the observer are proposed based on observer. By using the Lyapunov stability theory, speed identification adaptive law is got. The gain of the observer can be obtained by solving two bilinear matrix inequalities. The simulation model of speed sensorless induction motor using direct torque control based on observer is built in the Matlab/Simulink. Simulation results show that the adaptive observer has good steady and dynamic performances and good robustness.