Pub Date : 2019-12-01DOI: 10.1109/ICC47138.2019.9123199
Abhilash Mony
A cluster of single gimbal control moment gyroscopes (CMGs) is commonly employed on spacecraft for generating large torques, for fast in-track and cross-track maneuvers. It is well-known that the presence of singular configurations presents challenges when using CMGs for high-precision maneuvers. In this paper, we pose the problem of steering the attitude dynamics of a spacecraft in the context of robotic motion planning, and investigate the use of a Rapidly-Exploring Random Trees (RRT) algorithm for singularity avoidance. The analogy exploited in this approach is that between a singularity and a solid obstacle in the motion planning problem. We demonstrate the effectiveness of the singularity avoidance algorithm through numerical simulation of a CMG cluster on a rigid spacecraft performing target acquisition. The study compares the performance, based on the error in the torque tracking and value of the singularity index for the RRT algorithm vis-a-vis conventional steering laws.
{"title":"RRT-Based Steering Law for Singularity Avoidance of Control Moment Gyros used for Spacecraft Target Acquisition","authors":"Abhilash Mony","doi":"10.1109/ICC47138.2019.9123199","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123199","url":null,"abstract":"A cluster of single gimbal control moment gyroscopes (CMGs) is commonly employed on spacecraft for generating large torques, for fast in-track and cross-track maneuvers. It is well-known that the presence of singular configurations presents challenges when using CMGs for high-precision maneuvers. In this paper, we pose the problem of steering the attitude dynamics of a spacecraft in the context of robotic motion planning, and investigate the use of a Rapidly-Exploring Random Trees (RRT) algorithm for singularity avoidance. The analogy exploited in this approach is that between a singularity and a solid obstacle in the motion planning problem. We demonstrate the effectiveness of the singularity avoidance algorithm through numerical simulation of a CMG cluster on a rigid spacecraft performing target acquisition. The study compares the performance, based on the error in the torque tracking and value of the singularity index for the RRT algorithm vis-a-vis conventional steering laws.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132431650","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123237
S. Ranjan, M. Vidyasagar
Compressed sensing refers to the recovery of high-dimensional but low-complexity entities from a small number of measurements. Two canonical examples of compressed sensing are the recovery of high-dimensional but sparse vectors, and high-dimensional but low-rank matrices. There is considerable literature on sufficient conditions for achieving these.In vector recovery, the restricted isometry property (RIP) and the robust null space property (RNSP) are two of the most commonly used sufficient conditions. Until recently, they were viewed as two separate sufficient conditions. However, in a recent paper [1], the present authors have shown that in fact the RIP implies the RNSP, thus establishing that any result in vector recovery that can be proved using the RIP can also be proved using the RNSP.In matrix recovery, the analogous sufficient conditions are the rank restricted isometry property (RRIP), and the rank robust null space property (RRNSP). Until now no relationship was available between the two properties. In the present paper, we show that the RRIP implies the RRNSP. Thus, as in the case of vector recovery, any result that can be proven using the rank restricted isometry property can also be proven using the rank restricted null space property.
{"title":"Rank Restricted Isometry Property Implies the Rank Robust Null Space Property in Compressed Sensing for Matrix Recovery","authors":"S. Ranjan, M. Vidyasagar","doi":"10.1109/ICC47138.2019.9123237","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123237","url":null,"abstract":"Compressed sensing refers to the recovery of high-dimensional but low-complexity entities from a small number of measurements. Two canonical examples of compressed sensing are the recovery of high-dimensional but sparse vectors, and high-dimensional but low-rank matrices. There is considerable literature on sufficient conditions for achieving these.In vector recovery, the restricted isometry property (RIP) and the robust null space property (RNSP) are two of the most commonly used sufficient conditions. Until recently, they were viewed as two separate sufficient conditions. However, in a recent paper [1], the present authors have shown that in fact the RIP implies the RNSP, thus establishing that any result in vector recovery that can be proved using the RIP can also be proved using the RNSP.In matrix recovery, the analogous sufficient conditions are the rank restricted isometry property (RRIP), and the rank robust null space property (RRNSP). Until now no relationship was available between the two properties. In the present paper, we show that the RRIP implies the RRNSP. Thus, as in the case of vector recovery, any result that can be proven using the rank restricted isometry property can also be proven using the rank restricted null space property.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132445963","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123235
Ravi kiran Inapakurthi, S. Miriyala, K. Mitra
Modelling the time series data generated from a complex and nonlinear industrial grinding unit mandates the use of sophisticated algorithms capable of efficiently approximating the system under consideration. Recurrent Neural Networks, which are proven to be competent enough to approximate many time series systems, can be utilized for identification of industrial grinding circuits. However, the usage of RNNs for system identification tool is limited due to the heuristic estimation of network hyper parameters viz., number of hidden layers to be explored, number of nodes in each hidden layer, activation function and number of previous time instances to be considered for capturing the dynamics of the process. In this study, we address this heuristic approach by proposing an algorithm which can determine the optimal values of these hyper parameters for RNNs. This optimal determination of hyper parameters is done by adopting a multi-objective optimization problem with maximization of the accuracy of the developed model and minimization of the number of nodes in the network as the two conflicting objectives. The performance of the proposed algorithm on a real life industrial grinding circuit data shows its success and competitiveness.
{"title":"Recurrent Neural Network Based Modelling of Industrial Grinding Time Series Data","authors":"Ravi kiran Inapakurthi, S. Miriyala, K. Mitra","doi":"10.1109/ICC47138.2019.9123235","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123235","url":null,"abstract":"Modelling the time series data generated from a complex and nonlinear industrial grinding unit mandates the use of sophisticated algorithms capable of efficiently approximating the system under consideration. Recurrent Neural Networks, which are proven to be competent enough to approximate many time series systems, can be utilized for identification of industrial grinding circuits. However, the usage of RNNs for system identification tool is limited due to the heuristic estimation of network hyper parameters viz., number of hidden layers to be explored, number of nodes in each hidden layer, activation function and number of previous time instances to be considered for capturing the dynamics of the process. In this study, we address this heuristic approach by proposing an algorithm which can determine the optimal values of these hyper parameters for RNNs. This optimal determination of hyper parameters is done by adopting a multi-objective optimization problem with maximization of the accuracy of the developed model and minimization of the number of nodes in the network as the two conflicting objectives. The performance of the proposed algorithm on a real life industrial grinding circuit data shows its success and competitiveness.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117009495","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123226
Ankur A. Kulkarni, Anupama Kowli
Many electric utilities offer peak rebate programs, which allow them to call for load curtailment from participating consumers but the actual curtailment is voluntary. In this case, consumers may be tempted to “free-ride” on the compliance of other participants. Care should be taken in designing an appropriate incentive structure that is both, attractive enough to induce the desired curtailment, but not too attractive to induce excessive participation. This paper casts the consumer participation problem in DR as a game and analyzes its equilibrium to ascertain the nature of consumer response. We provide insights on the role of incentives and number of consumers called for curtailment, in inducing the desired curtailment.
{"title":"Addressing the Free-rider Problem in Voluntary Demand Response Programs","authors":"Ankur A. Kulkarni, Anupama Kowli","doi":"10.1109/ICC47138.2019.9123226","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123226","url":null,"abstract":"Many electric utilities offer peak rebate programs, which allow them to call for load curtailment from participating consumers but the actual curtailment is voluntary. In this case, consumers may be tempted to “free-ride” on the compliance of other participants. Care should be taken in designing an appropriate incentive structure that is both, attractive enough to induce the desired curtailment, but not too attractive to induce excessive participation. This paper casts the consumer participation problem in DR as a game and analyzes its equilibrium to ascertain the nature of consumer response. We provide insights on the role of incentives and number of consumers called for curtailment, in inducing the desired curtailment.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116837127","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123202
S. Ahmad, Bhushan Deo, Ahmad Ali
This paper proposes a modified active disturbance rejection control (ADRC) scheme for improved dynamic performance. A modified extended state observer (ESO) based on desired closed loop dynamics is constructed to estimate and discard the effect of unknown system dynamics and disturbances. Simple tuning rules are presented based on existing bandwidth parameterization method. Effectiveness of the proposed scheme is demonstrated through simulation study conducted on a variety of process models. The proposed scheme exhibits better tracking performance as well as disturbance attenuation than ADRC despite having same controller and observer bandwidths. Furthermore, the compact form of modified control scheme significantly reduces design and implementation complexity.
{"title":"Modified Active Disturbance Rejection Control for Improved Performance","authors":"S. Ahmad, Bhushan Deo, Ahmad Ali","doi":"10.1109/ICC47138.2019.9123202","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123202","url":null,"abstract":"This paper proposes a modified active disturbance rejection control (ADRC) scheme for improved dynamic performance. A modified extended state observer (ESO) based on desired closed loop dynamics is constructed to estimate and discard the effect of unknown system dynamics and disturbances. Simple tuning rules are presented based on existing bandwidth parameterization method. Effectiveness of the proposed scheme is demonstrated through simulation study conducted on a variety of process models. The proposed scheme exhibits better tracking performance as well as disturbance attenuation than ADRC despite having same controller and observer bandwidths. Furthermore, the compact form of modified control scheme significantly reduces design and implementation complexity.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125997360","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123196
K. Siddhardha, J. G. Manathara
Riding on a quadrotor in a standing position demands extreme piloting skills. However, niche tasks like certain inspection and rescue missions can be accomplished by doing so. In this paper, we propose a control scheme that uses the center of gravity (CoG) variation caused by the tilt of the pilot standing on a quadrotor to maneuver it in the horizontal plane. Keeping potential applications in mind, we design controllers for two modes of operation: a) Maneuver via leaning mode during which the quadrotor converts the forward CoG shift into a proportional forward speed, and the sideward CoG shift to a yaw rate, thus enabling a turn, and b) Remote control mode in which the quadrotor platform rejects all the disturbances including the pilot’s movements and maintains the desired speed and turn commands provided by the pilot using a hand-held remote control. We use a simplified model of a human standing on a quadrotor to test the proposed control laws using simulations. The simulation results show that it is possible to control the quadrotor motion using CoG shifts caused by a pilot with moderate skills.
{"title":"Quadrotor hoverboard","authors":"K. Siddhardha, J. G. Manathara","doi":"10.1109/ICC47138.2019.9123196","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123196","url":null,"abstract":"Riding on a quadrotor in a standing position demands extreme piloting skills. However, niche tasks like certain inspection and rescue missions can be accomplished by doing so. In this paper, we propose a control scheme that uses the center of gravity (CoG) variation caused by the tilt of the pilot standing on a quadrotor to maneuver it in the horizontal plane. Keeping potential applications in mind, we design controllers for two modes of operation: a) Maneuver via leaning mode during which the quadrotor converts the forward CoG shift into a proportional forward speed, and the sideward CoG shift to a yaw rate, thus enabling a turn, and b) Remote control mode in which the quadrotor platform rejects all the disturbances including the pilot’s movements and maintains the desired speed and turn commands provided by the pilot using a hand-held remote control. We use a simplified model of a human standing on a quadrotor to test the proposed control laws using simulations. The simulation results show that it is possible to control the quadrotor motion using CoG shifts caused by a pilot with moderate skills.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129452721","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123155
Bharadwaj Satchidanandan, P. Kumar
We consider a multiple-input, multiple-output perfectly observed linear dynamical system with an arbitrary set of malicious sensors and actuators. The honest actuators watermark their control inputs and perform certain tests to detect the presence of malicious sensors. The state space of such a system can be decomposed into two orthogonal subspaces, called the watermark-securable and the watermark-unsecurable subspaces, such that no matter what attack strategy the malicious sensors and actuators employ, they cannot degrade the state estimation performance of the honest sensors and actuators along the watermark-securable subspace if they wish to remain undetected. This paper characterizes a certain subset of the watermark-securable subspace.
{"title":"On the Watermark-Securable Subspace of a Linear Stochastic System","authors":"Bharadwaj Satchidanandan, P. Kumar","doi":"10.1109/ICC47138.2019.9123155","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123155","url":null,"abstract":"We consider a multiple-input, multiple-output perfectly observed linear dynamical system with an arbitrary set of malicious sensors and actuators. The honest actuators watermark their control inputs and perform certain tests to detect the presence of malicious sensors. The state space of such a system can be decomposed into two orthogonal subspaces, called the watermark-securable and the watermark-unsecurable subspaces, such that no matter what attack strategy the malicious sensors and actuators employ, they cannot degrade the state estimation performance of the honest sensors and actuators along the watermark-securable subspace if they wish to remain undetected. This paper characterizes a certain subset of the watermark-securable subspace.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129336309","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123178
Mohit Malhotra, M. Rohith, J. Myala, V. Patel
The Air to Air Refueling (AAR) is a force multiplier in application of airpower. Flight testing task for the Indian Light Combat Aircraft (LCA) Tejas was accomplished in August 2018. This paper presents the philosophy of clearing the Control Laws (CLAW) by Handling Qualities (HQ) assessment through a simulator, challenges and the outcome from the flight test results of the actual AAR task.
{"title":"Perfecting Handling Qualities Assessment Task on Simulator and Outcome of Actual Flight Test for Air to Air Refueling","authors":"Mohit Malhotra, M. Rohith, J. Myala, V. Patel","doi":"10.1109/ICC47138.2019.9123178","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123178","url":null,"abstract":"The Air to Air Refueling (AAR) is a force multiplier in application of airpower. Flight testing task for the Indian Light Combat Aircraft (LCA) Tejas was accomplished in August 2018. This paper presents the philosophy of clearing the Control Laws (CLAW) by Handling Qualities (HQ) assessment through a simulator, challenges and the outcome from the flight test results of the actual AAR task.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127157514","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123200
N. Mohanty, Akshath Singhal, T.K. Dan, P. Sujit
This paper presents a Linear Quadratic Regulator (LQR) based approach for cooperative path following problem for multiple UAVs along with collision avoidance. The goal of each vehicle, in a fleet, is to track a given desired trajectory and coordinate with other vehicles to be in a desired formation, while avoiding collision with each other. We model the cooperative path following problem as an infinite horizon LQR problem which is solved to obtain the velocity and steering control commands. Numerical simulations for different geometric paths are evaluated to verify the efficacy of our proposed method.
{"title":"LQR-based Cooperative Path Following of Multiple UAVs with Collision Avoidance","authors":"N. Mohanty, Akshath Singhal, T.K. Dan, P. Sujit","doi":"10.1109/ICC47138.2019.9123200","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123200","url":null,"abstract":"This paper presents a Linear Quadratic Regulator (LQR) based approach for cooperative path following problem for multiple UAVs along with collision avoidance. The goal of each vehicle, in a fleet, is to track a given desired trajectory and coordinate with other vehicles to be in a desired formation, while avoiding collision with each other. We model the cooperative path following problem as an infinite horizon LQR problem which is solved to obtain the velocity and steering control commands. Numerical simulations for different geometric paths are evaluated to verify the efficacy of our proposed method.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130144596","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 : 2019-12-01DOI: 10.1109/ICC47138.2019.9123184
U. Rajeev
Mission design and guidance for interplanetary travel utilizing the manifold structure of restricted three-body problem is investigated. Interplanetary space vehicle is simultaneously influenced by the gravitational attraction of multiple celestial bodies. Coupled, multi-body dynamics is classically solved by approximating it as a sequence of two-body problems. Based on the recent interest in the application of multi-body dynamics in the space mission design, a mission segment for transfer from an L1 Lyapunov orbit to L2 Lyapunov orbit is studied for the Earth-Moon system. Mission designs with manifold structure may not always yield continuous trajectories. Moreover, initial condition of the mission may not lie on the manifold. A closed loop guidance scheme based on feedback linearization is developed to ensure that the spacecraft tracks the manifold structure irrespective of the initial deviations and trajectory discontinuities.
{"title":"Interplanetary Mission Design and Guidance Based on Space Manifold Dynamics","authors":"U. Rajeev","doi":"10.1109/ICC47138.2019.9123184","DOIUrl":"https://doi.org/10.1109/ICC47138.2019.9123184","url":null,"abstract":"Mission design and guidance for interplanetary travel utilizing the manifold structure of restricted three-body problem is investigated. Interplanetary space vehicle is simultaneously influenced by the gravitational attraction of multiple celestial bodies. Coupled, multi-body dynamics is classically solved by approximating it as a sequence of two-body problems. Based on the recent interest in the application of multi-body dynamics in the space mission design, a mission segment for transfer from an L1 Lyapunov orbit to L2 Lyapunov orbit is studied for the Earth-Moon system. Mission designs with manifold structure may not always yield continuous trajectories. Moreover, initial condition of the mission may not lie on the manifold. A closed loop guidance scheme based on feedback linearization is developed to ensure that the spacecraft tracks the manifold structure irrespective of the initial deviations and trajectory discontinuities.","PeriodicalId":231050,"journal":{"name":"2019 Sixth Indian Control Conference (ICC)","volume":"2011 25","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113966209","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：