Pub Date : 2023-04-01DOI: 10.1051/jnwpu/20234120354
Xiao-Ke Ma, Qing'an Li, Yonghui Zhang, W. Fan
Coupling model for two-dimensional mixed-compression supersonic inlet with Mach number of 2.5 at design point and pulse detonation combustor was established, and three working schemes were designed to investigate multi cycle working process by using unsteady numerical simulation with chemical reaction. The results show that the following two measurements can both restrain the back-propagating compression wave and broaden the stability margin of the inlet and increase the frequency, one of which is the pressure relief at the outlet of the combustor, the other is valve at the inlet of the combustor. Nevertheless, the former will lose thrust, while the latter can greatly increase thrust. Meanwhile, the valve will reflect the compression wave in the production; increase the turbulence in the combustor, and make the gas entrained into the diffuser section of the inlet at the moment of opening the valve. However, the reflected compression wave in the hot production will not affect the velocity and shape of the detonation wave. Furthermore, in the period of detonation wave initiation and propagation, the blockage ratio of physical obstructions at the inlet of the combustor should be expanded as much as possible. At the same time, the flow at the outlet of the inlet should not be blocked to increase the flow resistance.
{"title":"Study on coupling characteristics of supersonic inlet and pulse detonation combustor","authors":"Xiao-Ke Ma, Qing'an Li, Yonghui Zhang, W. Fan","doi":"10.1051/jnwpu/20234120354","DOIUrl":"https://doi.org/10.1051/jnwpu/20234120354","url":null,"abstract":"Coupling model for two-dimensional mixed-compression supersonic inlet with Mach number of 2.5 at design point and pulse detonation combustor was established, and three working schemes were designed to investigate multi cycle working process by using unsteady numerical simulation with chemical reaction. The results show that the following two measurements can both restrain the back-propagating compression wave and broaden the stability margin of the inlet and increase the frequency, one of which is the pressure relief at the outlet of the combustor, the other is valve at the inlet of the combustor. Nevertheless, the former will lose thrust, while the latter can greatly increase thrust. Meanwhile, the valve will reflect the compression wave in the production; increase the turbulence in the combustor, and make the gas entrained into the diffuser section of the inlet at the moment of opening the valve. However, the reflected compression wave in the hot production will not affect the velocity and shape of the detonation wave. Furthermore, in the period of detonation wave initiation and propagation, the blockage ratio of physical obstructions at the inlet of the combustor should be expanded as much as possible. At the same time, the flow at the outlet of the inlet should not be blocked to increase the flow resistance.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43081250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/jnwpu/20234120419
Liuna Jia, Mianmian Dong, Chuchao He, Ruo-hai Di, Xiaoyan Li
Local search algorithm in ordering space is a good method which can effectively improve the efficiency of bayesian network structure learning. However, the existing algorithms usually have problems such as insufficient order optimization, low learning accuracy, and easy stop at a local optimal. In order to solve these problems, the local search algorithm in ordering space is studied, and a new method to improve the accuracy of bayesian network structure learning by optimizing order search operator is proposed. Combining the iterative local search algorithm with the window operator to search the neighborhood of a given order in the ordering space, the probability of the algorithm falling into the local optimal value is reduced, and the network structure with higher quality is obtained. Experimental results show that comparing with the bayesian network structure learning algorithm in network structure space, the learning efficiency of the present algorithm is improved by 54.12%. Comparing with the bayesian network structure learning algorithm in ordering space, the learning accuracy of the present algorithm is improved by 2.33%.
{"title":"A Bayesian network structure learning method for optimizing ordering search operator","authors":"Liuna Jia, Mianmian Dong, Chuchao He, Ruo-hai Di, Xiaoyan Li","doi":"10.1051/jnwpu/20234120419","DOIUrl":"https://doi.org/10.1051/jnwpu/20234120419","url":null,"abstract":"Local search algorithm in ordering space is a good method which can effectively improve the efficiency of bayesian network structure learning. However, the existing algorithms usually have problems such as insufficient order optimization, low learning accuracy, and easy stop at a local optimal. In order to solve these problems, the local search algorithm in ordering space is studied, and a new method to improve the accuracy of bayesian network structure learning by optimizing order search operator is proposed. Combining the iterative local search algorithm with the window operator to search the neighborhood of a given order in the ordering space, the probability of the algorithm falling into the local optimal value is reduced, and the network structure with higher quality is obtained. Experimental results show that comparing with the bayesian network structure learning algorithm in network structure space, the learning efficiency of the present algorithm is improved by 54.12%. Comparing with the bayesian network structure learning algorithm in ordering space, the learning accuracy of the present algorithm is improved by 2.33%.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44628391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/jnwpu/20234120400
Y. Li, Junsheng Wu, Weigang Li, Wei Dong, Aiqing Fang
Combat intent recognition refers to analyzing the enemy target's state information to interpret and judge the purpose of the enemy. With the increased knowledge of combat platforms, these time-series enemy state presents multi-dimensional and massive characteristics. Using neural networks to learn enemy state information has become a research trend in the face of such traits. To address these challenges, we propose a hierarchical aggregation model to recognize the intention of the target. The bottom layer of our model is based on convolutional neural network(CNN) to perceive behavior features, and the middle layer is based on Bi-LSTM(Bi-directional long short-term memory) to aggregate the long-time interdependence information between sub-intentions. The top layer focuses on higher-level features that contribute more to the recognition of intent through the attention mechanism and finally combines the global information to recognize the intention. Extensive experimental results show the superiority of our model in that the recognition accuracy achieves 88.83%, which can solve the problem of identifying air target intent on the modern battlefield.
{"title":"A hierarchical aggregation model for combat intention recognition","authors":"Y. Li, Junsheng Wu, Weigang Li, Wei Dong, Aiqing Fang","doi":"10.1051/jnwpu/20234120400","DOIUrl":"https://doi.org/10.1051/jnwpu/20234120400","url":null,"abstract":"Combat intent recognition refers to analyzing the enemy target's state information to interpret and judge the purpose of the enemy. With the increased knowledge of combat platforms, these time-series enemy state presents multi-dimensional and massive characteristics. Using neural networks to learn enemy state information has become a research trend in the face of such traits. To address these challenges, we propose a hierarchical aggregation model to recognize the intention of the target. The bottom layer of our model is based on convolutional neural network(CNN) to perceive behavior features, and the middle layer is based on Bi-LSTM(Bi-directional long short-term memory) to aggregate the long-time interdependence information between sub-intentions. The top layer focuses on higher-level features that contribute more to the recognition of intent through the attention mechanism and finally combines the global information to recognize the intention. Extensive experimental results show the superiority of our model in that the recognition accuracy achieves 88.83%, which can solve the problem of identifying air target intent on the modern battlefield.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46495980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/jnwpu/20234120253
Lei Liu, D. Teng, Yun Feng
To effectively monitor the reliability of civil aircraft flap deflection angle, combined with the quick access recorder(QAR), the collaborative intelligent moving Kriging(CIMK) method is proposed by absorbing the Kriging model, decomposition and co-ordination strategy, equilibrium optimizer(EO), and moving least square(MLS). Among them, the decomposition coordination strategy is used to deal with the relationship between the flaps left and right deflection angles. MLS is employed to select effective modeling samples and solve the undetermined coefficients of Kriging model. EO method is applied to determine optimizing the local compact support region radius of MLS. Firstly, the fault reason for flap left-right asymmetry is analyzed to clarify the main characteristic parameters in QAR data. Secondly, combined with the QAR data of relevant influencing parameters, the civil aircraft flap deflection model(limit state function) is constructed by using CIMK. Then, the reliability and influence of civil aircraft flap deflection angle are analyzed by Monte Carlo(MC) sampling method. The results show that when the flap deflection angle is 3°, the reliability is 0.450 2, and the important factors affecting the flap deflection angle are Mach number, left angle of attack, right angle of attack, etc. Compared with the response surface method(RSM), Kriging, support vector machine(SVM), and back-propagation-artificial neural network(BP-ANN), the average absolute error accuracy of the proposed method is relative improved by 53.02%, 51.43%, 49.03%, and 44.04%, the average relative error accuracy is relative improved by 68.36%, 66.76%, 64.41%, and 62.64%, and the modeling efficiency is relative improved by 50.62%, 26.35%, and 43.01% respectively compared with Kriging, SVM and BP-ANN. When the number of simulations is 103, the analysis accuracy is relative improved by 8.82%, 7.25%, 6.22%, and 3.98% respectively.
{"title":"Reliability analysis of flap deflection angle based on collaborative intelligent moving Kriging model","authors":"Lei Liu, D. Teng, Yun Feng","doi":"10.1051/jnwpu/20234120253","DOIUrl":"https://doi.org/10.1051/jnwpu/20234120253","url":null,"abstract":"To effectively monitor the reliability of civil aircraft flap deflection angle, combined with the quick access recorder(QAR), the collaborative intelligent moving Kriging(CIMK) method is proposed by absorbing the Kriging model, decomposition and co-ordination strategy, equilibrium optimizer(EO), and moving least square(MLS). Among them, the decomposition coordination strategy is used to deal with the relationship between the flaps left and right deflection angles. MLS is employed to select effective modeling samples and solve the undetermined coefficients of Kriging model. EO method is applied to determine optimizing the local compact support region radius of MLS. Firstly, the fault reason for flap left-right asymmetry is analyzed to clarify the main characteristic parameters in QAR data. Secondly, combined with the QAR data of relevant influencing parameters, the civil aircraft flap deflection model(limit state function) is constructed by using CIMK. Then, the reliability and influence of civil aircraft flap deflection angle are analyzed by Monte Carlo(MC) sampling method. The results show that when the flap deflection angle is 3°, the reliability is 0.450 2, and the important factors affecting the flap deflection angle are Mach number, left angle of attack, right angle of attack, etc. Compared with the response surface method(RSM), Kriging, support vector machine(SVM), and back-propagation-artificial neural network(BP-ANN), the average absolute error accuracy of the proposed method is relative improved by 53.02%, 51.43%, 49.03%, and 44.04%, the average relative error accuracy is relative improved by 68.36%, 66.76%, 64.41%, and 62.64%, and the modeling efficiency is relative improved by 50.62%, 26.35%, and 43.01% respectively compared with Kriging, SVM and BP-ANN. When the number of simulations is 103, the analysis accuracy is relative improved by 8.82%, 7.25%, 6.22%, and 3.98% respectively.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42283203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110018
Ting Li, Yeming Yao, Linhai Zhang, Yang Li, Xinmin Wang
The internal leakage fault-tolerant control problem of the electro-hydraulic servo actuator under the influence of multiple unmodeled dynamics is investigated in this paper, and an adaptive fault-tolerant control scheme based on unmodeled dynamics estimation and compensation is proposed. The model of the actuator is divided into two subsystems, which extended-state observers are respectively constructed to estimate the matched and mismatched unmodeled dynamics. Combined with the estimation results of the unmodeled dynamics, an adaptive fault-tolerant controller is designed by using the backstepping method. In which a controller reconfiguration mechanism based on internal leakage fault parameter online adaptation is used to accommodate the fault, and a feedforward compensation strategy is used to suppress the influence of unmodeled dynamics. Semi-physical simulation test of the proposed scheme is conducted under serious cylinder internal leakage. The test result shows that when the maximum internal leakage flow reaches 10.53 L/min, accounting for about 56.77% of the load flow, at the moment the opening of the servovalve is close to the maximum and the proposed scheme can still achieve high-precision position tracking control, where the maximum position tracking errors of fault transient and post-fault steady state are both limited within ±1.5% of the given position.
{"title":"Adaptive fault-tolerant control for electro-hydraulic servo actuator based on multiple unmodeled dynamics estimation and compensation","authors":"Ting Li, Yeming Yao, Linhai Zhang, Yang Li, Xinmin Wang","doi":"10.1051/jnwpu/20234110018","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110018","url":null,"abstract":"The internal leakage fault-tolerant control problem of the electro-hydraulic servo actuator under the influence of multiple unmodeled dynamics is investigated in this paper, and an adaptive fault-tolerant control scheme based on unmodeled dynamics estimation and compensation is proposed. The model of the actuator is divided into two subsystems, which extended-state observers are respectively constructed to estimate the matched and mismatched unmodeled dynamics. Combined with the estimation results of the unmodeled dynamics, an adaptive fault-tolerant controller is designed by using the backstepping method. In which a controller reconfiguration mechanism based on internal leakage fault parameter online adaptation is used to accommodate the fault, and a feedforward compensation strategy is used to suppress the influence of unmodeled dynamics. Semi-physical simulation test of the proposed scheme is conducted under serious cylinder internal leakage. The test result shows that when the maximum internal leakage flow reaches 10.53 L/min, accounting for about 56.77% of the load flow, at the moment the opening of the servovalve is close to the maximum and the proposed scheme can still achieve high-precision position tracking control, where the maximum position tracking errors of fault transient and post-fault steady state are both limited within ±1.5% of the given position.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45450244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110081
K. Sun, Bo Li, Zhongjiang Yan, Mao Yang
Aiming at the problems existing in the current mechanisms of delay guarantee in wireless networks(i.e. poor scalability, coarse granularity for provided service levels, and improving delay performance at the expense of sacrificing some resource utilization), this paper puts forward both the idea of particle access and the corresponding access mechanism. In this paper, a traffic flow is modeled as a group of information particles that carry a certain amount of information and are valid for certain periods of time. Firstly, the definitions of information particles and the group of information particles are given. It is proved that the minimum reachable access bandwidth of an information particle group can be achieved by using the EDF(earliest deadline first) transmission strategy. Moreover, a fine-grained mechanism of delay guarantee based on the idea of particle access is proposed for the dynamic access environment in wireless networks. Extensive simulations are carried out for the application scenario of downlink transmissions, and it is shown that, in the case of heavy traffic loads, comparing with the rapid growth of the average packet delays and the packet loss rates in a legacy access mechanism, the proposed fine-grained access strategy based on the idea of particle access can also achieve the better performance on the average packet delays and the packet loss rates, and hence higher effective throughput is obtained. The research in this paper pave a new way for further improving quality of service (QoS) mechanisms of wireless networks.
{"title":"Study on fine-grained mechanism of delay guarantee based on idea of particle access in wireless networks","authors":"K. Sun, Bo Li, Zhongjiang Yan, Mao Yang","doi":"10.1051/jnwpu/20234110081","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110081","url":null,"abstract":"Aiming at the problems existing in the current mechanisms of delay guarantee in wireless networks(i.e. poor scalability, coarse granularity for provided service levels, and improving delay performance at the expense of sacrificing some resource utilization), this paper puts forward both the idea of particle access and the corresponding access mechanism. In this paper, a traffic flow is modeled as a group of information particles that carry a certain amount of information and are valid for certain periods of time. Firstly, the definitions of information particles and the group of information particles are given. It is proved that the minimum reachable access bandwidth of an information particle group can be achieved by using the EDF(earliest deadline first) transmission strategy. Moreover, a fine-grained mechanism of delay guarantee based on the idea of particle access is proposed for the dynamic access environment in wireless networks. Extensive simulations are carried out for the application scenario of downlink transmissions, and it is shown that, in the case of heavy traffic loads, comparing with the rapid growth of the average packet delays and the packet loss rates in a legacy access mechanism, the proposed fine-grained access strategy based on the idea of particle access can also achieve the better performance on the average packet delays and the packet loss rates, and hence higher effective throughput is obtained. The research in this paper pave a new way for further improving quality of service (QoS) mechanisms of wireless networks.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43818874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110056
Yongfeng Li, Yongxi Lyu, Jingping Shi, Weihua Li
To solve the enemy uncertain manipulation problem during a UAV's autonomous air combat maneuver decision-making, this paper proposes an autonomous air combat maneuver decision-making method that combines target maneuver command prediction with the deep deterministic policy algorithm. The situation data of both sides of air combat are effectively fused and processed, the UAV's six-degree-of-freedom model and maneuver library are built. In air combat, the target generates its corresponding maneuver library instructions through the deep Q network algorithm; at the same time, the UAV on our side gives the target maneuver prediction results through the probabilistic neural network. A deep deterministic policy gradient reinforcement learning method that considers both the situation information of two aircraft and the prediction results of enemy aircraft is proposed, so that the UAV can choose the appropriate maneuver decision according to the current air combat situation. The simulation results show that the method can effectively use the air combat situation information and target maneuver prediction information so that it can improve the effectiveness of the reinforcement learning method for UAV's autonomous air combat decision-making on the premise of ensuring convergence.
{"title":"UAV's air combat decision-making based on deep deterministic policy gradient and prediction","authors":"Yongfeng Li, Yongxi Lyu, Jingping Shi, Weihua Li","doi":"10.1051/jnwpu/20234110056","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110056","url":null,"abstract":"To solve the enemy uncertain manipulation problem during a UAV's autonomous air combat maneuver decision-making, this paper proposes an autonomous air combat maneuver decision-making method that combines target maneuver command prediction with the deep deterministic policy algorithm. The situation data of both sides of air combat are effectively fused and processed, the UAV's six-degree-of-freedom model and maneuver library are built. In air combat, the target generates its corresponding maneuver library instructions through the deep Q network algorithm; at the same time, the UAV on our side gives the target maneuver prediction results through the probabilistic neural network. A deep deterministic policy gradient reinforcement learning method that considers both the situation information of two aircraft and the prediction results of enemy aircraft is proposed, so that the UAV can choose the appropriate maneuver decision according to the current air combat situation. The simulation results show that the method can effectively use the air combat situation information and target maneuver prediction information so that it can improve the effectiveness of the reinforcement learning method for UAV's autonomous air combat decision-making on the premise of ensuring convergence.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48617050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To overcome the adverse effects of noise and shadow regions on target detection in side-scan sonar images, more precisely, it is difficult to accurately detect targets, a target detection technology based on a multi-region optimal selection strategy of spectral clustering combined with the entropy weight method is proposed in this study. First, the cluster numbers for spectral clustering are set in advance based on prior knowledge, and the pixels of the sonar image are clustered into several different regions. Second, the invariable features of translation, rotation and scaling up that each region is extracted and used to construct the feature criterion matrix for the multiple regions. Last, the entropy weight method is used to calculate the weights of each feature and the comprehensive weighted score of each region for this feature criterion matrix to obtain the final target region. Experimental results show that the proposed method can effectively overcome the adverse effects of noise and shadow regions in side-scan sonar images, but also achieve the selection of optimal target region among multiple regions after image clustering, thus verifying the feasibility and effectiveness of the proposed method in this study.
{"title":"Sonar image target detection based on multi-region optimal selection strategy","authors":"Yu Cao, Guangyu Liu, Linlin Mu, Zhiyong Zeng, Enming Zhao, Chuanxi Xing","doi":"10.1051/jnwpu/20234110153","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110153","url":null,"abstract":"To overcome the adverse effects of noise and shadow regions on target detection in side-scan sonar images, more precisely, it is difficult to accurately detect targets, a target detection technology based on a multi-region optimal selection strategy of spectral clustering combined with the entropy weight method is proposed in this study. First, the cluster numbers for spectral clustering are set in advance based on prior knowledge, and the pixels of the sonar image are clustered into several different regions. Second, the invariable features of translation, rotation and scaling up that each region is extracted and used to construct the feature criterion matrix for the multiple regions. Last, the entropy weight method is used to calculate the weights of each feature and the comprehensive weighted score of each region for this feature criterion matrix to obtain the final target region. Experimental results show that the proposed method can effectively overcome the adverse effects of noise and shadow regions in side-scan sonar images, but also achieve the selection of optimal target region among multiple regions after image clustering, thus verifying the feasibility and effectiveness of the proposed method in this study.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46405705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The spontaneous radiation combustion diagnosis technology has high requirements for obtaining the radiation intensity of highly directional resolution in a combustion system. Taking advantage of the numerical stability and easy implementation of the element differential method, this paper constructs a radiation model that can achieve the radiation intensity of spatial and angular high-resolution in cylindrical anisotropic scattering medium. In analyzing the radiation model, the radiation intensity is discretized in three dimensions. An upwind scheme is proposed to suppress the numerical oscillation of the strong convection characteristics of the radiation transfer equation. The double-layer node algorithm is used to capture the strong discontinuous singularities at the radiation boundary. The comparison with the analytical solution shows that the radiation model based on the element differential method can achieve the high-resolution description of radiation intensity with high-order accuracy. The accuracy and validity of the radiation model are verified through comparing with the results on the Monte Carlo method. The further description of the three-dimensional distribution of radiation intensity in angle and space proves that the up-wind scheme can effectively suppress numerical oscillation and realize stable calculation.
{"title":"Analyzing thermal radiation in cylindrical anisotropic scattering medium with element differential method","authors":"Yifang Li, Yasong Sun, Huabo Zhang, Sida Li, Changhao Liu, Jing Ma","doi":"10.1051/jnwpu/20234110090","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110090","url":null,"abstract":"The spontaneous radiation combustion diagnosis technology has high requirements for obtaining the radiation intensity of highly directional resolution in a combustion system. Taking advantage of the numerical stability and easy implementation of the element differential method, this paper constructs a radiation model that can achieve the radiation intensity of spatial and angular high-resolution in cylindrical anisotropic scattering medium. In analyzing the radiation model, the radiation intensity is discretized in three dimensions. An upwind scheme is proposed to suppress the numerical oscillation of the strong convection characteristics of the radiation transfer equation. The double-layer node algorithm is used to capture the strong discontinuous singularities at the radiation boundary. The comparison with the analytical solution shows that the radiation model based on the element differential method can achieve the high-resolution description of radiation intensity with high-order accuracy. The accuracy and validity of the radiation model are verified through comparing with the results on the Monte Carlo method. The further description of the three-dimensional distribution of radiation intensity in angle and space proves that the up-wind scheme can effectively suppress numerical oscillation and realize stable calculation.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41337582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For the requirement of structural deformation measurement, a deformation measurement method based on structured light point clouds is proposed. A structured light measurement system is built, and the calibration process based on the assumption of the projector's reverse camera and with the help of the checkerboard calibration board is completed. The pattern projected by the projector is designed by using a four-step phase-shift technique assisted by Gray code. By combining with system parameters which have been calibrated, the three-dimensional reconstruction of the object surface is completed. A structural deformation measurement method based on the statistical analysis of the distance between point clouds is proposed, and the principles of three points cloud distance calculation methods including point-to-point, point-to-surface and surface-to-surface are analyzed. The feasibility and accuracy of the deformation measurement method based on the structured light point cloud proposed in this paper are verified via experiments. Experimental results show that this method can achieve out-plane high-precision displacement measurement of structures.
{"title":"Study on deformation measurement method based on structured light point clouds","authors":"Weizhong Xiao, Yingtao Yuan, Zhendong Ge, Xiang Guo, Tao Suo, Qi Yu","doi":"10.1051/jnwpu/20234110047","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110047","url":null,"abstract":"For the requirement of structural deformation measurement, a deformation measurement method based on structured light point clouds is proposed. A structured light measurement system is built, and the calibration process based on the assumption of the projector's reverse camera and with the help of the checkerboard calibration board is completed. The pattern projected by the projector is designed by using a four-step phase-shift technique assisted by Gray code. By combining with system parameters which have been calibrated, the three-dimensional reconstruction of the object surface is completed. A structural deformation measurement method based on the statistical analysis of the distance between point clouds is proposed, and the principles of three points cloud distance calculation methods including point-to-point, point-to-surface and surface-to-surface are analyzed. The feasibility and accuracy of the deformation measurement method based on the structured light point cloud proposed in this paper are verified via experiments. Experimental results show that this method can achieve out-plane high-precision displacement measurement of structures.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45102302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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