Journal of Liaoning Petrochemical University
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Fault Diagnosis of Chemical Processes Based on Attention⁃Enhanced Encoder⁃Decoder Network
Qilei XIA, Lin LUO, Yao ZHANG
Abstract511)   HTML1)    PDF (1687KB)(24)      

The data of chemical processes often contains dynamic timing characteristics, and traditional fault detection has low usage of dynamic information, which limits the fault diagnosis performance. To address this problem,a new method of chemical process fault diagnosis based on an attention?enhanced encoder?decoder network model (AEN) was proposed. The coding part uses the LSTM to extract the feature information of the process data and combine it with the attention mechanism to utilize the dynamic information among the process data more effectively; the decoding part uses the LSTM and combines the context vector provided by the attention mechanism to provide more accurate state information for the softmax regression, and finally, the softmax regression is used to obtain the probability value of the fault category for each sample data. The introduction of the attention mechanism improves the efficiency of the model in using process dynamic information in the time domain. The proposed method is experimented with using Tennessee Eastman process data and compared with the results of standard PCA?SVM, DBN and ResNet, and the results show that the proposed method is more effective in diagnosing faults.

2024, 44 (2): 63-70. DOI: 10.12422/j.issn.1672-6952.2024.02.010
Energy Change of Pipeline Signal Spatial Propagation Detected by Magnetic Tomography Method
Linlin LIU, Lijian YANG, Songwei GAO
Abstract533)   HTML2)    PDF (1947KB)(17)      

Magnetic tomography method has been widely used for nondestructive external inspection of buried and submarine pipelines, which is based on the principle of metal magnetic memory to discern the danger level and location of the stress concentration zone by measuring the anomalies in the spatial magnetic field distribution outside the pipeline. The distribution characteristics and spatial propagation law of pipeline inspection signal detected by magnetic tomography method, the energy distribution and change law of spatial magnetic memory signal in the stress concentration zone of magnetized pipelines are studied in this paper. The magnetic dipole field is used to establish the magnetic field model in the stress concentration zone of the inner wall of the pipeline, and the magnetic energy and energy density of spatial magnetic memory signals under different lift?off values outside the pipeline are finite element calculated based on the magnetic energy theory to derive the distribution law of spatial magnetic field and the correlation of magnetic energy density of magnetic signals under different lift?off value is analyzed. The results show that the spatial magnetic field energy outside the pipe decays with the increase of lift?off value, and the decay is the fastest within the distance of 50 mm from the outer wall of the pipe to the physical force; the correlation of magnetic energy density of different lift?off values shows that the magnetic signal detected by magnetic tomography method outside the pipe is homologous with the signal in the stress concentration zone of the inner wall of the pipe. Theoretically, it explains the effectiveness of magnetic tomography method and also provides evaluation indexes for extracting effective signals from the detection data.

2024, 44 (2): 71-76. DOI: 10.12422/j.issn.1672-6952.2024.02.011
Research on Migration of Flying Gangue Based on Geographic Information System in Steeply Dipping Coal Seam
Haochen WANG, Ming LIU, Jie CHEN
Abstract473)   HTML2)    PDF (1998KB)(19)      

In view of the irregularity of the bottom floor of working face and the diversity of the shape of the flying gangue in steeply dipping coal seam, based on the geographic information system data such as contour line of bottom floor of working face, the 3d grid model of bottom floor is established, combined with the energy tracking method(ETM) C + + programs, four typical shapes of flying gangue with the same mass and different shapes are simulated to obtain the motion trajectories of the migration of flying gangue in the actual working face, as well as the velocity, angular velocity and energy change curves at any time. The influence of the shapes on the motion of flying gangue is analyzed. In order to verify the accuracy and feasibility of the method in this paper, the trajectory simulated by Rockyfor3D software is compared. The results show that the transport capacity of ellipsoidal flying gangue is much higher than that of polyhedral flying gangue. Compared with common polyhedral flying gangue, the regular polyhedral flying gangue has farther migration distance and less energy loss due to collision. The number of edges of flying gangue of regular polyhedron is inversely proportional to the energy loss of flying gangue in collision, which indicates that flying gangue of regular polyhedron with multiple edges is most likely to cause danger.

2024, 44 (2): 77-82. DOI: 10.12422/j.issn.1672-6952.2024.02.012
Research on Weather Recognition Based on Image Segmentation and Multi⁃Head Attention Mechanism
Xufeng ZHAO, Linlin LIU, Yu CAO, Chengyin YE, Zongkai GUO
Abstract467)   HTML4)    PDF (1793KB)(28)      

Recognition of weather phenomena based on images is essential for the analysis of weather conditions. To address the problems that traditional machine learning methods are difficult to accurately extract various weather features and poor in classifying weather phenomena and the accuracy of deep learning for weather phenomena recognition is not high, a weather recognition model based on image block and multi?headed attention mechanism is proposed. The model introduces Swin Transformer into the field of weather recognition for the first time, and adopts a multi?headed attention mechanism combining window multi?head self?attention layer and shifted?window multi?head self?attention layer, whose regionally relevant features extraction capability makes up for the shortcomings of traditional methods and can extract complex weather features from images. The model is trained using transfer learning, and the fully connected parameters of the fine?tuned model are input to the Softmax classifier to achieve recognition of multi?category weather images with 99.20% recognition accuracy, which is better than several mainstream methods in comparison, and it can be applied to ground weather recognition systems as a weather recognition module.

2024, 44 (2): 83-90. DOI: 10.12422/j.issn.1672-6952.2024.02.013
Capacitance Tomography Image Reconstruction Algorithm Based on Confined Particle Swarm
Yuanna JIAO, Zhenhua ZUO, Leilei ZHANG, Zhiheng GUO, Zhe KAN
Abstract28)   HTML2)    PDF (1469KB)(21)      

The robustness of the particle swarm system is great, which is very helpful for solving ill?conditioned problems such as image reconstruction. However, the large number of pixels in the reconstructed image leads to a large dimension of particle and it is difficult for the particle to achieve the optimal solution in the optimization process. In order to solve this problem, a constraint is added to the particle position, imaging by Tikhonov regularization algorithm is used as the reference of particle position. The search for particles is constrained to the range of Tikhonov regularization algorithm reconstructs the image. Using the penalty function to solve the constraint problem to improve the particle search speed. Linearly decreasing weights as inertial weights for particle swarms optimization to realize the adaptive dynamic adjustment of the inertia weight and improve the flexibility of the algorithm; the chaotic operator is added to the position search process of the particle swarm optimization, when the particle falls into the local optimum, the chaotic variable will fluctuate within a certain range, reducing the missed rate of the optimal solution. The simulation results show that The improved particle swarm algorithm is more accurate and efficient than the traditional LBP algorithm and Tikhonov regularization algorithm.

2024, 44 (2): 91-96. DOI: 10.12422/j.issn.1672-6952.2024.02.014
Collaborative Air⁃Ground Tracking Control of Unmanned Helicopter Based on Obstacle Avoidance Path Planning
Jingwen YANG, Tao LI, Xin YANG, Mingfei JI
Abstract804)   HTML5)    PDF (1706KB)(53)      

The paper aims to study the problem of obstacle avoidance in air?ground cooperative tracking control for the unmanned aerial helicopter (UAH),in which a new approach of designing the path obstacle avoidance plan and controller design is proposed.Initially, as for the uncertain linear UAH,by processing and judging two?dimensional environmental information within the warning range for the UAH,an obstacle avoidance strategy is proposed with the help of wall?following algorithm,and the flight angle of obstacle avoidance path and the tracking speed that can make up for bypass distance are calculated.Secondly,the proposed obstacle avoidance method is extended to the three?dimensional case,and the flight angle of the UAH is determined based on the obstacle information in the horizontal and vertical directions,which can reduce the bypass distance caused by the obstacle avoidance link as possible.Thirdly,based on two derived obstacle avoidance algorithms above,the artificial neural network (ANN) is introduced to estimate model uncertainty,and then the tracking control design schemes are established by using feedforward compensation and optimal control technologies.some simulations demonstrate the effectiveness of the proposed obstacle avoidance strategy and control algorithm.

2024, 44 (1): 71-79. DOI: 10.12422/j.issn.1672-6952.2024.01.011
Research on Virus Propagation Prediction Based on Informer Algorithm
Wanjie CHANG, Linlin LIU, Yu CAO, Yang CAO, Haiping WEI
Abstract674)   HTML4)    PDF (2606KB)(46)      

The COVID?19 epidemic is facing the influence of a variety of complex practical factors, which makes the development of the epidemic uncertain. In order to overcome the problem of large error in epidemic forecasting results due to the limitations of many ideal assumptions based on the infectious disease compartment model, a time series forecasting model based on deep learning is adopted to predict the epidemic development, and an informer model based on transformer model is established. Attention mechanism and distillation mechanism are applied to the time series forecasting of epidemic data. The threshold autoregressive (TAR) model and a variety of mainstream recurrent neural time series prediction models are used as comparison models. Through simulation experiments, the current number of remaining infections in the epidemic data of China, America and Britain is predicted in the short term, and RMSE and MAE are used as evaluation indicators, and then the best model is selected for medium ? and long?term prediction. The experimental results show that the indicator value of the informer model is optimal in both RMSE and MAE, further indicating that the prediction accuracy of the informer model is higher than that of other comparative models in China, America and Britain. Finally, the Informer model is used for the development of the epidemic in China,America and Britain medium and long?term prediction.

2024, 44 (1): 80-88. DOI: 10.12422/j.issn.1672-6952.2024.01.012
Research on the Evaluation of Supply Chain Resilience in Petrochemical Enterprises under the Dual Circulation: Based on AHP⁃BP Method
Lizhou ZHAO, Ningfeng ZHANG
Abstract606)   HTML15)    PDF (1193KB)(76)      

With the improvement of environmental uncertainty, the demand for supply chain stability of petrochemical enterprises in China is rising day by day. The evaluation of supply chain resilience of petrochemical enterprises has become an important means to judge the risk coping ability of petrochemical enterprises. This paper constructs a supply chain resilience evaluation index system in the petrochemical enterprises. And fuzzy analytic hierarchy process and BP neural network are used to evaluate the toughness strength of petrochemical enterprise supply chain, so as to determine the toughness level of petrochemical enterprise supply chain.It is found that the strength of supply chain toughness of petrochemical enterprises is uneven, and the overall level of supply chain resilience is low. On the basis of the research results, some practical suggestions are put forward for the forging of resilient supply chain in petrochemical enterprises.

2024, 44 (1): 89-96. DOI: 10.12422/j.issn.1672-6952.2024.01.013
Energy Balanced Leach Optimization Algorithm Based on Cluster Head Node Selection
Yinghao WU, Yuanbo SHI, Yueyang HUANG
Abstract76)   HTML4)    PDF (1580KB)(60)      

In order to solve the problems of short life cycle and low data throughput caused by too fast energy consumption in cluster head node selection of LEACH protocol in wireless sensor networks, a leach optimization algorithm based on cluster head node energy balanced selection is proposed. The algorithm selects ordinary nodes with high residual energy in WSNs as cluster head nodes, and considers the distance between ordinary nodes and cluster head nodes and between cluster head nodes and base station, as well as the residual energy and average energy of all nodes to select communication mode and transmission path. The proposed algorithm is simulated by MATLAB. The simulation results show that in the 100 m×100 m small and monitoring area and 200 m×200 m large and monitoring area, compared with LEACH, DEEC and IMP?LEACH algorithms, the algorithm reduces the energy consumption of nodes in WSNs, prolongs the life cycle and improves the data throughput.

2023, 43 (6): 82-88. DOI: 10.12422/j.issn.1672-6952.2023.06.013
3D Point Cloud Processing Model Based on Local Position Adaptation
Jian HOU, Heng LIU, Linke LIU, Bin PAN, Yuping ZHANG
Abstract76)   HTML6)    PDF (2223KB)(51)      

In the field of point cloud processing, deep learning is a mainstream method, but the existing methods do not fully utilize the local structure information of 3D point clouds, and have less local shape perception. We proposes a 3D point cloud processing model based on improved PoinetNet. Network model introduces position adaptive convolution into PointNet. The position?adaptive convolution constructs the kernel function by combining the weight matrices in the weight bank in a dynamic way, in which the coefficients of the weight matrix are adaptively learned from the relative positions of the points through the position?relative coefficient network. The kernel function constructed in this way can better solve the problem of irregularity and disorder of point cloud data. The classification accuracy of the position?adaptive network in the 3D object classification experiment is 3.60% higher than that of PointNet, and the average intersection ratio in the 3D object part segmentation experiment is 2.20% higher than that of PointNet. In the 3D scene semantics In the segmentation experiment, the average intersection and union ratio is improved by 9.14% compared with PointNet.

2023, 43 (6): 89-96. DOI: 10.12422/j.issn.1672-6952.2023.06.014
Research on Transformer Fault Diagnosis Model Based on Improved Bidirectional Recurrent Neural Network
Xun ZHAO, Shuai CHEN, Haiyang QIU
Abstract110)   HTML9)    PDF (1721KB)(111)      

Aiming at the problems of traditional neural network in mining transformer time series relationship, poor generalization of classification and low accuracy of classification for heterogeneous data, this paper proposes an improved transformer fault diagnosis model based on bidirectional recurrent neural network. The model extracts features through bidirectional recurrent neural network, fuses the features at the front and back time, classifies the feature data using multi?kernel learning support vector machine method, and fuses the features in multi?kernel learning support vector machine, so as to improve the accuracy of feature data classification. The accuracy and validity of the bidirectional recurrent neural network based on multi?kernel learning support vector machine model are tested through numerical simulation analysis of the temporal channel length for sequential network diagnostic performance, the influence of and multi?kernel learning on the generalization ability of support vector machines, and the influence on heterogeneous data processing capabilities. The experimental results show that the diagnosis performance of the bidirectional recurrent neural network based on multi?kernel learning support vector machine is better, and the prediction accuracy of the model is higher than that of several commonly used neural networks.

2023, 43 (5): 75-83. DOI: 10.12422/j.issn.1672-6952.2023.05.012
Research on Constant Current Braking about DC Motor and Dynamic Control Method of Falling Speed of Lifting Objects
Boming HUANG, Haicheng BAI, Xiangguo JIANG
Abstract72)   HTML4)    PDF (1273KB)(71)      

The fast braking of resistant load and the falling speed control of the potential energy load are of great significance to improve the operation efficiency and the safety of motor drive equipments. In this paper, a method of constant current braking and dynamic adjustment of falling speed of lifiting objects for DC motor is proposed, in which the conventional energy consumption braking resistor is replaced by a power MOSFET and the equivalent resistance between its leakage and source can be adjusted by voltage control. Under the condition of no need to change the hardware, the double closed?loop control technology of current and speed is adopted to realize the requirements of the whole process constant current fast parking brake, the fast dropping of suspended objects and the falling speed continous adjustment control in the motor drive system. Theoretical analysis and experimental results show that the time for the parking brake and the time for the falling speed of the liftting object to reach stability are reduced respectively to 66.7% and 33.3% of the conventional braking method without chaning changing the hardware system, which effectively improves the dynamic working efficiency of the motor drive system and the flexibility of the control system.

2023, 43 (5): 84-90. DOI: 10.12422/j.issn.1672-6952.2023.05.013
Research on Bank Long‒Term Customer Deposit Prediction Based on Neural Network
Chunyue YU, Yu CAO, Xu CHENG
Abstract117)   HTML6)    PDF (1009KB)(119)      

Due to the huge amount of the customers'data the rise of various financial products and the short?term impact of the epidemic, banks are facing with increasing pressure resulting in the business volume declined sharply. The traditional classification tree model can not make more accurate prediction of long?term deposits and carry out accurate marketing to customers according to customer information. Therefore, this paper proposes a three?layer neural network model. Through the experiment, the customer data of grape Island banking institutions are predicted, and compared with the prediction results of a traditional decision tree, random forest model, AdaBoost model and XGBoost model. The experiment shows that compared with the other four models, the neural network model has a better effect of prediction, the model evaluation AUC reaches 0.977 7 and the accuracy reaches 99.06%.

2023, 43 (5): 91-96. DOI: 10.12422/j.issn.1672-6952.2023.05.014
Dynamic Matrix Control of Thermal Efficiency of Tubular Furnace Based on PSO Algorithm
Haojie Ye, Wenna Li
Abstract121)   HTML8)    PDF (848KB)(133)      

In the research on the thermal efficiency of atmospheric tube heating furnaces, it is necessary to conduct effective online measurement of thermal efficiency and select relatively reliable advanced control methods. On the basis of the research on the combustion mechanism of the heating furnace, the online measurement method based on the principle and data processing is used to process the thermal efficiency, and the "dynamic matrix control" is introduced in the process of optimizing the control of the heating furnace efficiency, which is compared with the traditional control method. The introduction of dynamic matrix control makes the system have a better control effect. At the same time, the "particle swarm algorithm" was selected to optimize the parameters of dynamic matrix control. In the optimization process of dynamic matrix parameters, the particle swarm algorithm relatively shortens the optimization time and improves the control quality, so as to achieve a more satisfactory control effect. Finally, compare with internal model control, it shows that dynamic matrix control can achieve relatively better control effect.

2023, 43 (3): 81-85. DOI: 10.12422/j.issn.1672-6952.2023.03.013
3D Skeleton Data Double Human Interaction Recognition Based on Graph Convolution Network
Jingting Zhang, Jiangtao Cao, Xiaofei Ji
Abstract133)   HTML3)    PDF (1774KB)(140)      

Aiming at the problem of insufficient representation of interactive semantic information in the double human interaction behavior recognition method based on graph convolutional neural networks,a new double human interactive spatial?temporal graph convolution network (DHI?STGCN) was proposed for behavior recognition. The network contains spatial sub?network modules and temporal sub?network modules. Based on the 3D skeleton data obtained from the interactive action video, a spatial action graph of double human interactive action was generated for the representation of spatial information. In the graph, the connecting edges between double human were given different weights according to the joint point position information. The connection of context time information was added in the constructed adjacency matrix, and the joint points in the graph were connected with their nodes within a certain time range in time information processing. The generated spatial?temporal graph data was sent to the spatial graph convolution network module, and the temporal graph convolution network module was combined to enhance the continuity of inter frame motion features for modeling in time. The model fully considers the close relationship of double human interaction. The comparative experimental results on NTU?RGB+D dataset show that the algorithm has strong robustness and obtains better interaction recognition effect than the existing models.

2023, 43 (3): 86-90. DOI: 10.12422/j.issn.1672-6952.2023.03.014
Structural Optimization Deep Network for Mechanical Fault Diagnosis of High Voltage Circuit Breakers
Nan Jiang, Lin Luo, Qiao Wang, Wei Hou
Abstract134)   HTML3)    PDF (1609KB)(114)      

The vibration signal during the operation of high voltage circuit breaker can reflect the mechanical state of circuit breaker. Aiming at the shortcomings of feature extraction and fault diagnosis accuracy of shallow vibration signal analysis model, a fault diagnosis method of high voltage circuit breaker based on convolutional neural network optimized by genetic algorithm was proposed. Using the global optimization ability of genetic algorithm, the optimal initial network structure parameters and the number of neurons in the whole connection layer were obtained through the selection, crossover and mutation of genetic algorithm to optimize the convolutional neural network, and the optimized convolutional neural network is applied to the fault diagnosis of high voltage circuit breaker. The results show that the diagnosis performance of the proposed network model is better than that of convolution neural network, dynamic support vector machine and multilayer perceptron.

2023, 43 (3): 91-96. DOI: 10.12422/j.issn.1672-6952.2023.03.015
Simulation Study on the Influence of Initial State on the Transmission Process of Infectious Diseases
Xinyuan Tong, Yu Cao, Haiping Wei
Abstract155)   HTML2147483647)    PDF (1094KB)(326)      

For a long time, researchers mostly analyze the transmission process of infected nodes in complex networks to get the target of forecasting and arresting the extend of the infectious diseases. In this article, the SEIR propagation dynamics model was extended to the undirected and powerless large small world network, and the weights between nodes were given as infection ability. Two initial node selection methods were selected to carry out multiple simulation experiments. Based on the traditional method of judging the impact of transmission by the number of infected people and infection threshold, the specific values of infection probability, peak value and inflection point time were added to analyze the impact of initial node selection on transmission process more comprehensively. The compared experimental results show that the initial node which the degree is larger and the betweenness is larger, the larger the propagation scale, the faster the propagation speed and the shorter the equilibrium time. This study provides some reference value for guard against and control of the extend of infectious diseases.

2023, 43 (2): 92-96. DOI: 10.12422/j.issn.1672-6952.2023.02.015
A Pipe Layout Sequence Optimization Method Based on Disassembly Complexity
Yuanjie Liu, Qiang Liu
Abstract113)   HTML3)    PDF (1456KB)(98)      

Aero?engine usually contains a large number of pipes, the arrangement sequence of these pipes has a certain impact on the overall layout effect of the system. In order to reduce the degree of cross layout of multiple pipes, the evaluation method of pipe disassembly complexity was designed based on product assembly and disassembly, a Discrete Chicken Swarm Optimization (DCSO) algorithm was used to solve the pipe layout sequence planning. First, a calculation method of pipe disassembly complexity was proposed to evaluate the complexity of pipe system layout scheme. Next, the pipe was pre?planned by A* algorithm. Then, an obstacle avoidance algorithm was designed based on engineering rules to adjust the pipe. Finally, taking the pipe length and disassembly complexity as the optimization objectives, the pipe layout sequence was optimized based on DCSO, and the feasibility of the proposed method was verified by a layout example.

2023, 43 (2): 86-91. DOI: 10.12422/j.issn.1672-6952.2023.02.014
An Efficient Implementation Method of the Apriori Algorithm and its Application
Chunxu Wu, Yinshan Jia, Hongfei Yu
Abstract120)   HTML4)    PDF (984KB)(324)      

Aiming at the low efficiency of Apriori algorithm in scanning database and low dimensional frequent itemset, an efficient implementation method of Apriori algorithm was proposed, which is called EI_Apriori algorithm. This method utilizes the vector?based storage structure and pre?pruning to reduce the number of scanning databases and low?dimensional frequent itemsets and thus improves the efficiency of the Apriori algorithm. According to the actual situation of student achievement analysis, the constraints on the sequence relationship between courses are added in the association rule mining, and the constraints on the score level range are added in the association rules. The adjusted EI_Apriori algorithm was applied in score association analysis. The results show that the EI_Apriori algorithm can accurately find the association rules that meet the real needs, which proves the superiority of EI_Apriori algorithm.

2023, 43 (2): 78-85. DOI: 10.12422/j.issn.1672-6952.2023.02.013
Application of Improved WLSSVM Model in the Prediction of Gasoline Dry Point at the Top of Atmospheric Towe
Junyong Cui, Qi′an Li
Abstract67)   HTML5)    PDF (1310KB)(139)      

The dry point of gasoline is difficult to be measured in real time. A large number of data samples need to be extracted to test the quality of each section of the oil. In order to solve this problem, predictive control was carried out by establishing a soft sensor model. The least squares support vector machine model is too sensitive to outliers, which is easy to affect the prediction accuracy. By establishing the weighted least squares support vector machine model (WLSSVM), the fitting error is weighted, which weakens the influence of outliers on the model and improves the anti?interference ability of the model. The improved WLSSVM was applied to the prediction of gasoline dry point. The results show that the maximum absolute error of the improved WLSSVM is 11.65% lower than that of the least squares support vector machine model, and its prediction performance and robustness have obvious advantages.

2023, 43 (1): 67-72. DOI: doi:10.12422/j.issn.1672-6952.2023.01.012
Improved Genetic Algorithm to Optimize Differences Control of Heater Bypass
Weiming Wang, Wenna Li
Abstract139)   HTML5)    PDF (1235KB)(123)      

Aiming at the problem of temperature tracking and balance control of each branch pipe of the heating furnace, an improved genetic algorithm was proposed to optimize the multi?deviation control of the temperature tracking and balance of the branch pipe temperature of the heating furnace. The scheme used the temperature deviation of the raw materials of each branch pipe after mixing and the temperature deviation of each branch pipe. By adjusting the feed flow rate and fuel flow rate, it not only ensured that the flow rate of the main pipe is constant during the regulation process, but also realized the dual goal of temperature tracking and balance of each pass. Multi?passes are analyzed as a whole, so the temperature comparison of adjacent branch pipes was avoided repeatedly. At the same time, the improved genetic algorithm was used to optimize the controller parameters of the differences control technique, which overcomes the difficulty of controller parameter tuning. The simulation results show the feasibility and effectiveness of the improved genetic algorithm to optimize the differences control scheme.

2023, 43 (1): 73-79. DOI: 10.12422/j.issn.1672-6952.2023.01.013
Multivariable ORVFL Network Adaptive Predictive Control Based on ISSA
Xinyu Na, Huapeng Yu, Xin Jin, Yue Wang
Abstract162)   HTML7)    PDF (1345KB)(263)      

For the MIMO nonlinear systems, a multivariable ORVFL neural network adaptive predictive control algorithm based on Improved Sparrow Search Algorithm was proposed in this paper. The algorithm uses the ORVFL network to approximate the nonlinear system model, and applies to the multi?step prediction of the system process. In order to improve the performance of the Sparrow Search Algorithm, the algorithm is used to optimize the system performance index online and solve the optimal control law of each sampling period. The results show that the algorithm has good control performance and good anti?model mismatch ability.

2023, 43 (1): 80-88. DOI: 10.12422/j.issn.1672-6952.2023.01.014
An Improved Brain MR Image Segmentation Algorithm Based on Markov Random Field
Guoliang Wang, Yunshuai Ren, Yang Wang
Abstract197)   HTML2147483647)    PDF (1368KB)(365)      

Gaussian mixture model (GMM) is easily affected by noise, and Markov random field (MRF) model can well describe the spatial characteristics. The combination of the two is suitable for image segmentation with noise, but MRF model is prone to over segmentation. To solve this problem, an improved image segmentation algorithm based on adaptive weight coefficient was proposed, which can segment cerebrospinal fluid, gray matter and white matter from magnetic resonance imaging (MRI). Firstly, the K?means algorithm was used to obtain the initial segmentation results, and the Expectation?Maximization (EM) algorithm was used to estimate the parameters of GMM, and then the joint probability energy function of the pixel gray level of the image was obtained. Then, the adaptive weight coefficient was obtained by using the gray value, posterior probability and Euclidean distance of the center pixel and the neighboring pixels of the MRF neighborhood system, and the prior probability energy function was obtained by MRF. Finally, the final image segmentation results were obtained by Bayesian criterion. Experimental results show that the algorithm has strong adaptability, can better overcome the impact of noise on image segmentation. Compared with similar algorithms, the proposed algorithm has higher segmentation accuracy for brain MR images with noise, and obtains better segmentation results.

2023, 43 (1): 89-96. DOI: 10.12422/j.issn.1672-6952.2023.01.015