Pub Date : 2010-06-08DOI: 10.1109/ISSCAA.2010.5633087
Fengxia Xu, Zhongda Lu, Dai Xuefeng
Based on all-round effect of error factor for PIGA, the paper establishes theoretical error models. Develops the testing of PIGA on the three- axes turntable, the analysis has shown that the input acceleration includes position error of the testing equipment. We use the testing data by the three- axes turntable to identify the error model of PIGA, and the total least squares method by the comparison with the least squares. The purpose of applying the total least squares method is to eliminate the influence of the testing equipment error to instrument precision, but the accuracy is superior to the least squares, which can enhance identification precision of the testing PIGA.
{"title":"The application of total least squares method in the error model identification of PIGA","authors":"Fengxia Xu, Zhongda Lu, Dai Xuefeng","doi":"10.1109/ISSCAA.2010.5633087","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5633087","url":null,"abstract":"Based on all-round effect of error factor for PIGA, the paper establishes theoretical error models. Develops the testing of PIGA on the three- axes turntable, the analysis has shown that the input acceleration includes position error of the testing equipment. We use the testing data by the three- axes turntable to identify the error model of PIGA, and the total least squares method by the comparison with the least squares. The purpose of applying the total least squares method is to eliminate the influence of the testing equipment error to instrument precision, but the accuracy is superior to the least squares, which can enhance identification precision of the testing PIGA.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"226 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124522325","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5632629
Xianlin Huang, Zejian Zhang, Kairui Cao, X. Z. Gao
A sufficient stability condition in the frequency domain is presented for a type of muti-rules proportional Takagi-Sugeno (T-S) fuzzy control system by using the technique of loop transformation and the circle criterion. This condition can be utilized to geometrically analyze the global asymptotical stability of such T-S fuzzy control system. Two numerical examples are given to illustrate how to use this condition to analyze the T-S fuzzy control systems.
{"title":"A sufficient stability condition for a type of proportional T-S fuzzy control system in the frequency domain","authors":"Xianlin Huang, Zejian Zhang, Kairui Cao, X. Z. Gao","doi":"10.1109/ISSCAA.2010.5632629","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5632629","url":null,"abstract":"A sufficient stability condition in the frequency domain is presented for a type of muti-rules proportional Takagi-Sugeno (T-S) fuzzy control system by using the technique of loop transformation and the circle criterion. This condition can be utilized to geometrically analyze the global asymptotical stability of such T-S fuzzy control system. Two numerical examples are given to illustrate how to use this condition to analyze the T-S fuzzy control systems.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127757728","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5633320
Zhiqiang Zhao, Zhengdong Hu
A rapid reentry trajectory planning method for a common aero vehicle (CAV) subject to all path constraints is developed. The reentry trajectory is divided into initial descent phase and quasi-equilibrium glide phase which possesses a majority of the reentry period. An improved quasi-equilibrium glide condition is utilized to convert reentry corridor constraints to the control variable constraints and get a simple relation between the range-to-go and velocity. Accordingly the longitudinal reference trajectory is computed through the one-parameter search of bank angle model and the corresponding tracking law is designed using linear quadratic regulator theory. To enhance the maneuvering capability, a geometrical control approach considering no-fly zone constraints is applied to the lateral guidance. Finally, the performance of this method is verified by computer simulation.
{"title":"A rapid reentry trajectory planning method for CAV","authors":"Zhiqiang Zhao, Zhengdong Hu","doi":"10.1109/ISSCAA.2010.5633320","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5633320","url":null,"abstract":"A rapid reentry trajectory planning method for a common aero vehicle (CAV) subject to all path constraints is developed. The reentry trajectory is divided into initial descent phase and quasi-equilibrium glide phase which possesses a majority of the reentry period. An improved quasi-equilibrium glide condition is utilized to convert reentry corridor constraints to the control variable constraints and get a simple relation between the range-to-go and velocity. Accordingly the longitudinal reference trajectory is computed through the one-parameter search of bank angle model and the corresponding tracking law is designed using linear quadratic regulator theory. To enhance the maneuvering capability, a geometrical control approach considering no-fly zone constraints is applied to the lateral guidance. Finally, the performance of this method is verified by computer simulation.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126453280","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5632258
Zhenqing Wang, H. Lv, A. Zhang
The flying vehicle will encounter severe aerodynamic heating and large drag due to shock wave when it is in hypersonic flight, spikes ahead of the blunt noses of bodies of revolution have been considered as a means of the total heat flux and aerodynamic drag reduction, while a conical shock wave induced by the spike instead of the former bow shock wave of the blunt body. In this paper, the influences of nose conFiguration such as conical, hemispherical and flat-headed spike and l / D ratio (where l is the spike length and D is cylinder diameter) on the reduction of aerodynamic drag and the heating are investigated. Studies have shown that, the thermal protective effect when use conical spike is remarkable, while the aerodynamic drag reduction is prominence when use flat-headed spike, and both more effective with increased l / D ratio when it is varying around 2.
{"title":"Numerical analysis of thermal protection and drag redunction with use of spike","authors":"Zhenqing Wang, H. Lv, A. Zhang","doi":"10.1109/ISSCAA.2010.5632258","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5632258","url":null,"abstract":"The flying vehicle will encounter severe aerodynamic heating and large drag due to shock wave when it is in hypersonic flight, spikes ahead of the blunt noses of bodies of revolution have been considered as a means of the total heat flux and aerodynamic drag reduction, while a conical shock wave induced by the spike instead of the former bow shock wave of the blunt body. In this paper, the influences of nose conFiguration such as conical, hemispherical and flat-headed spike and l / D ratio (where l is the spike length and D is cylinder diameter) on the reduction of aerodynamic drag and the heating are investigated. Studies have shown that, the thermal protective effect when use conical spike is remarkable, while the aerodynamic drag reduction is prominence when use flat-headed spike, and both more effective with increased l / D ratio when it is varying around 2.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134057918","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5633350
G. Ma, Haibin Huang, Yufei Zhuang
In this paper we employ pseudospectral method to solve the problem of trajectory optimization for satellites formation reconfiguration in deep space. The basic problem is all the satellites take a specified rest-to-rest maneuver synchronously without colliding with each other. First, the state and input vectors are discretized at Legendre-Gauss-Lobatto (LGL) points, and the objective function is selected as minimizing the total fuel consumption during maneuver. Then the optimization problem is converted into a parameter nonlinear programming problem with the non-convex constraints of collision avoidance as inequality equations using Legendre pseudospectral method. At the end of this paper, an example is worked out and the simulation results demonstrate that the proposed approach can produce high approximation accuracy and a small computational amount, which makes the algorithm of trajectory generation for formation reconfiguration used on-line possible.
{"title":"Deep space formation reconfiguration using pseudospectral method","authors":"G. Ma, Haibin Huang, Yufei Zhuang","doi":"10.1109/ISSCAA.2010.5633350","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5633350","url":null,"abstract":"In this paper we employ pseudospectral method to solve the problem of trajectory optimization for satellites formation reconfiguration in deep space. The basic problem is all the satellites take a specified rest-to-rest maneuver synchronously without colliding with each other. First, the state and input vectors are discretized at Legendre-Gauss-Lobatto (LGL) points, and the objective function is selected as minimizing the total fuel consumption during maneuver. Then the optimization problem is converted into a parameter nonlinear programming problem with the non-convex constraints of collision avoidance as inequality equations using Legendre pseudospectral method. At the end of this paper, an example is worked out and the simulation results demonstrate that the proposed approach can produce high approximation accuracy and a small computational amount, which makes the algorithm of trajectory generation for formation reconfiguration used on-line possible.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131158130","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5633970
Hai Zhao, D. Cao, Xinqun Zhu
The problem of flutter and limit cycle oscillation (LCO) for two-degrees-of freedom airfoil with structural and aerodynamic nonlinearities is addressed in this paper. The model which includes freeplay in pitching is established using the Lagrange equation. The aerodynamic lift and moment are derived in terms of the 3rd-order piston theory. The forth order Runge-Kutta method is employed to solve the nonlinear dynamic equations numerically. Period response, multi-periodic response and chaotic motion are observed after investigating the phase plane and power spectral density diagrams. Bifurcation diagram of the pitching is obtained with gradually increasing values of the dimensionless air speed. The results indicate that the critical flutter speed is lower than that of the system without freeplay. It can be also concluded from the simulation that the initial value and the magnitude of the freeplay have significant effects on the dynamic motion of the system in both regions of stable and LCO. The dimensionless air speed region in which the system behaves chaotic motion is wider than that reported in the existing literature.
{"title":"Aerodynamic flutter and limit cycle analysis for a 2-D wing with pitching freeplay in the supersonic flow","authors":"Hai Zhao, D. Cao, Xinqun Zhu","doi":"10.1109/ISSCAA.2010.5633970","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5633970","url":null,"abstract":"The problem of flutter and limit cycle oscillation (LCO) for two-degrees-of freedom airfoil with structural and aerodynamic nonlinearities is addressed in this paper. The model which includes freeplay in pitching is established using the Lagrange equation. The aerodynamic lift and moment are derived in terms of the 3rd-order piston theory. The forth order Runge-Kutta method is employed to solve the nonlinear dynamic equations numerically. Period response, multi-periodic response and chaotic motion are observed after investigating the phase plane and power spectral density diagrams. Bifurcation diagram of the pitching is obtained with gradually increasing values of the dimensionless air speed. The results indicate that the critical flutter speed is lower than that of the system without freeplay. It can be also concluded from the simulation that the initial value and the magnitude of the freeplay have significant effects on the dynamic motion of the system in both regions of stable and LCO. The dimensionless air speed region in which the system behaves chaotic motion is wider than that reported in the existing literature.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130986591","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5633090
Xuhui Yu, Huilian Ma, Zhong-he Jin
Resonator fiber optic gyroscope has the potential to achieve the inertial navigation system requirement with a short sensing coil. An all digitalized system is constructed including the signal modulation /demodulation and a proportional integral (PI) controller in a single field programmable gate array. Under this scheme, the serrodyne phase modulation technique is adopted, which is of benefit to overcome the backscattering induced noise and easy to implement in closed-loop operation. The phase modulation index is optimized to achieve high carrier suppression. The PI controller is adopted in the frequency servo loop to eliminate the residual error at the lock-in frequency. A bias stability of 5.2×10−4 rad/s in 500 seconds is demonstrated experimentally.
{"title":"Resonator fiber optic gyroscope with an all digitalized system","authors":"Xuhui Yu, Huilian Ma, Zhong-he Jin","doi":"10.1109/ISSCAA.2010.5633090","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5633090","url":null,"abstract":"Resonator fiber optic gyroscope has the potential to achieve the inertial navigation system requirement with a short sensing coil. An all digitalized system is constructed including the signal modulation /demodulation and a proportional integral (PI) controller in a single field programmable gate array. Under this scheme, the serrodyne phase modulation technique is adopted, which is of benefit to overcome the backscattering induced noise and easy to implement in closed-loop operation. The phase modulation index is optimized to achieve high carrier suppression. The PI controller is adopted in the frequency servo loop to eliminate the residual error at the lock-in frequency. A bias stability of 5.2×10−4 rad/s in 500 seconds is demonstrated experimentally.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134498424","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5632562
Chunyang Liu, Zhanxue Wang, Jiaqi Wang, F. Yin, Kong Deying
The flow field distribution characteristic of a clamshell thrust reverser with flap deployed while landing is investigated based on Computational Fluid Dynamics (CFD) technology. The mesh was generated with unstructured tetrahedron and unstructured hexahedron meshes and S-A turbulent model in solving Reynolds averaged N-S equations is adopted. The results show, in the range of landing speed between 136.1m/s and 17.0m/s, the hot reverse exhaust flow from the clamshell thrust reverser is not re-injected into the engine inlet; and it impinges on part of the aerofoil and pylon. As landing speed decreases, the hot reverse exhaust flow spreads forward and laterally deeper, so it may be re-injected by near engine inlet if the aerofoil sweepback is large enough, which will result in inlet distortion. When landing speed decreases down to 34m/s, the hot reverse exhaust flow starts to impinge on the ground, which may wind up some dross to the inlet. At last, the reverse thrust decreases as landing speed decreases.
{"title":"3D numerical simulation of clamshell thrust reverser with flap deployed while landing","authors":"Chunyang Liu, Zhanxue Wang, Jiaqi Wang, F. Yin, Kong Deying","doi":"10.1109/ISSCAA.2010.5632562","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5632562","url":null,"abstract":"The flow field distribution characteristic of a clamshell thrust reverser with flap deployed while landing is investigated based on Computational Fluid Dynamics (CFD) technology. The mesh was generated with unstructured tetrahedron and unstructured hexahedron meshes and S-A turbulent model in solving Reynolds averaged N-S equations is adopted. The results show, in the range of landing speed between 136.1m/s and 17.0m/s, the hot reverse exhaust flow from the clamshell thrust reverser is not re-injected into the engine inlet; and it impinges on part of the aerofoil and pylon. As landing speed decreases, the hot reverse exhaust flow spreads forward and laterally deeper, so it may be re-injected by near engine inlet if the aerofoil sweepback is large enough, which will result in inlet distortion. When landing speed decreases down to 34m/s, the hot reverse exhaust flow starts to impinge on the ground, which may wind up some dross to the inlet. At last, the reverse thrust decreases as landing speed decreases.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115190433","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5633234
Jie Li, T. Chai, Lisheng Fan, Li Pan, Jingkuan Gong
The PID controller is one of the most popular controllers, due to its remarkable effectiveness, simplicity of implementation and broad applicability. However, the conventional approach for parameter optimization in PID controller is easy to produce surge and big overshoot, and therefore heuristics optimization methods such as genetic algorithm (GA), particle swarm optimization (PSO) are employed to enhance the capability of traditional techniques. One major problem of these algorithms is that they may be trapped in the local optima of the objective and lead to poor performance. In this paper, a novel stochastic optimization technique named particle filter optimization (PFO) is proposed to achieve better performance in dealing with local optima while reduce the computation complexity of PID parameter tuning process. Simulation results indicate that the proposed algorithm is effective and efficient, and demonstrate that the proposed algorithm exhibits a significant performance improvement over several other benchmark methods.
{"title":"PID controller tuning using particle filtering optimization","authors":"Jie Li, T. Chai, Lisheng Fan, Li Pan, Jingkuan Gong","doi":"10.1109/ISSCAA.2010.5633234","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5633234","url":null,"abstract":"The PID controller is one of the most popular controllers, due to its remarkable effectiveness, simplicity of implementation and broad applicability. However, the conventional approach for parameter optimization in PID controller is easy to produce surge and big overshoot, and therefore heuristics optimization methods such as genetic algorithm (GA), particle swarm optimization (PSO) are employed to enhance the capability of traditional techniques. One major problem of these algorithms is that they may be trapped in the local optima of the objective and lead to poor performance. In this paper, a novel stochastic optimization technique named particle filter optimization (PFO) is proposed to achieve better performance in dealing with local optima while reduce the computation complexity of PID parameter tuning process. Simulation results indicate that the proposed algorithm is effective and efficient, and demonstrate that the proposed algorithm exhibits a significant performance improvement over several other benchmark methods.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115568490","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 : 2010-06-08DOI: 10.1109/ISSCAA.2010.5633028
Jun Wang, Xi-yuan Peng, Yu Peng
One of the most difficult problems facing the user of clustering analysis techniques in practice is the objective assessment of the stability and validity of the clusters found by the numerical technique used. The problem of determining the “true” number of clusters has been called the fundamental problem of cluster validity. In this paper, a validity index for clustering with penalizing method is proposed, maximization of which ensures the formation of a small number of compact clusters with large separation between at least two clusters. Experimental results are provided to demonstrate the superiority of this index as compared to five well-known validity indexes by using the k-means and fuzzy c-means algorithms.
{"title":"Validity index for clustering with penalizing method","authors":"Jun Wang, Xi-yuan Peng, Yu Peng","doi":"10.1109/ISSCAA.2010.5633028","DOIUrl":"https://doi.org/10.1109/ISSCAA.2010.5633028","url":null,"abstract":"One of the most difficult problems facing the user of clustering analysis techniques in practice is the objective assessment of the stability and validity of the clusters found by the numerical technique used. The problem of determining the “true” number of clusters has been called the fundamental problem of cluster validity. In this paper, a validity index for clustering with penalizing method is proposed, maximization of which ensures the formation of a small number of compact clusters with large separation between at least two clusters. Experimental results are provided to demonstrate the superiority of this index as compared to five well-known validity indexes by using the k-means and fuzzy c-means algorithms.","PeriodicalId":324652,"journal":{"name":"2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115028162","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：