This paper investigates the robust repetitive controller design with improved tracking performance for nano-manipulating systems with time delay. In order to handle the time delay caused by the analog-to-digital (A/D) conversion of the capacitive sensors with ultra high precision, we modify the conventional repetitive control structure where the design of low pass filter is formulated as an H∞ optimization problem. For the purpose of tracking performance improvement, we further modify the structure of the low pass filter by shaping the sensitivity functions of the closed-loop system. With consideration of the existing of model uncertainties, the design of the modified low pass filter is also formulated as an H∞ optimization of infinite dimensional systems. The effectiveness of the proposed repetitive control architecture is further verified by real time experiments on a piezo driven nano-stage, where significant tracking performance improvements are demonstrated comparing with the traditional repetitive controller.
{"title":"Tracking Performance Improvement of Repetitive Controller for Nano-Manipulating Systems With Time Delays","authors":"Pengbo Liu, P. Yan","doi":"10.1115/detc2019-97313","DOIUrl":"https://doi.org/10.1115/detc2019-97313","url":null,"abstract":"\u0000 This paper investigates the robust repetitive controller design with improved tracking performance for nano-manipulating systems with time delay. In order to handle the time delay caused by the analog-to-digital (A/D) conversion of the capacitive sensors with ultra high precision, we modify the conventional repetitive control structure where the design of low pass filter is formulated as an H∞ optimization problem. For the purpose of tracking performance improvement, we further modify the structure of the low pass filter by shaping the sensitivity functions of the closed-loop system. With consideration of the existing of model uncertainties, the design of the modified low pass filter is also formulated as an H∞ optimization of infinite dimensional systems. The effectiveness of the proposed repetitive control architecture is further verified by real time experiments on a piezo driven nano-stage, where significant tracking performance improvements are demonstrated comparing with the traditional repetitive controller.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124201913","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}
Fractional calculus is a powerful tool for dealing with complex systems, and fractional flow component can effectively reflect the nonlinear gradual change of rheology in vibration state. Besides, higher-order logic theorem proving is a formal method for specification and verification. This paper, accordingly, presents a higher-order logic formalization of fractional flow component based on fractional calculus Caputo definition. The relationship between fractional order differential and integer order differential is verified according to fractional calculus Caputo definition in higher-order logic theorem proving, where fluid mechanics fractional flow component is then formally analyzed.
{"title":"Formalization of Fractional Flow Component in Higher-Order Logic Theorem Proving","authors":"Chunna Zhao, Murong Jiang, Yaqun Huang","doi":"10.1115/detc2019-97209","DOIUrl":"https://doi.org/10.1115/detc2019-97209","url":null,"abstract":"\u0000 Fractional calculus is a powerful tool for dealing with complex systems, and fractional flow component can effectively reflect the nonlinear gradual change of rheology in vibration state. Besides, higher-order logic theorem proving is a formal method for specification and verification. This paper, accordingly, presents a higher-order logic formalization of fractional flow component based on fractional calculus Caputo definition. The relationship between fractional order differential and integer order differential is verified according to fractional calculus Caputo definition in higher-order logic theorem proving, where fluid mechanics fractional flow component is then formally analyzed.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116013985","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}
This paper studies the chattering-free finite-time control for a class of fractional-order nonlinear systems. First, a class of fractional-order nonlinear systems with external disturbances is presented. Second, a new finite-time terminal sliding mode control method is proposed for the stability control of a class of fractional-order nonlinear systems by combining the finite-time stability theory and sliding mode control scheme. Third, by designing a controller with a differential form and introducing the arc tangent function, the chattering phenomenon is well suppressed. Additionally, a controller is developed to resist external disturbances. Finally, numerical simulations are implemented to demonstrate the feasibility and validity of the proposed method.
{"title":"Chattering-Free Finite-Time Stability of a Class of Fractional-Order Nonlinear Systems","authors":"Bin Wang, Y. Chen, Yingshan Yang","doi":"10.1115/detc2019-97674","DOIUrl":"https://doi.org/10.1115/detc2019-97674","url":null,"abstract":"\u0000 This paper studies the chattering-free finite-time control for a class of fractional-order nonlinear systems. First, a class of fractional-order nonlinear systems with external disturbances is presented. Second, a new finite-time terminal sliding mode control method is proposed for the stability control of a class of fractional-order nonlinear systems by combining the finite-time stability theory and sliding mode control scheme. Third, by designing a controller with a differential form and introducing the arc tangent function, the chattering phenomenon is well suppressed. Additionally, a controller is developed to resist external disturbances. Finally, numerical simulations are implemented to demonstrate the feasibility and validity of the proposed method.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115167253","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}
Smart farming focuses on the application of intelligent and autonomous machines to make agricultural production more effective. The development of Agriculture Unmanned Ground Vehicle (AUGV) makes it possible to utilize smart, small, intelligent robots in agriculture. Even existing AUGVs have been used in many fields, their disadvantages have limited the promotion of current AUGV system. Based on the demands of farmers, a new Low Cost Smart Agriculture Unmanned Ground Vehicle (LCS-AUGV) system is proposed. The challenges and opportunities of LCS-AUGV are discussed, and the frame work of LCS-AUGV is designed. The designed LCS-AUGV includes two subsystems: Unmanned Ground Vehicle System (UGVS) and Remote Control System (RCS), and diagrams of each subsystem are designed and described in detail. The measuring and control system (MCS) of LCS-AUGV is designed, and hierarchical structure is introduced into MCS. The new MCS principle can add or remove super information center easily, thus the high performance and low cost of the system can be taken into account. Based on the proposed MCS, a five-level control strategy is designed. The designed control strategy includes Basic Level Control (BLC), Low Level Control (HLC), Super Level Control (SLC), Agriculture Mission Based Control (AMBC). A LCS-AUGV platform is built at the basis of the designed frame work, and the cost analysis is performed. According to the analysis, the hardware cost can be controlled below $1000, while most super function can be realized. The typical applications also are described. LCS-AUGV provides an ideal platform for most smart farming tasks and is easily to be accepted by farmers. The LCS-AUGV also can be used in high level intelligence agriculture field, and be selected as a new algorithm’s research platform.
{"title":"Smart and Autonomous Farm Field Scouting Service Robot As an Edge Device Under $1000: Challenges and Opportunities","authors":"Junwei Tian, Haoyu Niu, Peng Wang, Y. Chen","doi":"10.1115/detc2019-98259","DOIUrl":"https://doi.org/10.1115/detc2019-98259","url":null,"abstract":"\u0000 Smart farming focuses on the application of intelligent and autonomous machines to make agricultural production more effective. The development of Agriculture Unmanned Ground Vehicle (AUGV) makes it possible to utilize smart, small, intelligent robots in agriculture. Even existing AUGVs have been used in many fields, their disadvantages have limited the promotion of current AUGV system. Based on the demands of farmers, a new Low Cost Smart Agriculture Unmanned Ground Vehicle (LCS-AUGV) system is proposed. The challenges and opportunities of LCS-AUGV are discussed, and the frame work of LCS-AUGV is designed. The designed LCS-AUGV includes two subsystems: Unmanned Ground Vehicle System (UGVS) and Remote Control System (RCS), and diagrams of each subsystem are designed and described in detail. The measuring and control system (MCS) of LCS-AUGV is designed, and hierarchical structure is introduced into MCS. The new MCS principle can add or remove super information center easily, thus the high performance and low cost of the system can be taken into account. Based on the proposed MCS, a five-level control strategy is designed. The designed control strategy includes Basic Level Control (BLC), Low Level Control (HLC), Super Level Control (SLC), Agriculture Mission Based Control (AMBC). A LCS-AUGV platform is built at the basis of the designed frame work, and the cost analysis is performed. According to the analysis, the hardware cost can be controlled below $1000, while most super function can be realized. The typical applications also are described. LCS-AUGV provides an ideal platform for most smart farming tasks and is easily to be accepted by farmers. The LCS-AUGV also can be used in high level intelligence agriculture field, and be selected as a new algorithm’s research platform.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125459772","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}
RIOTS is a general purpose optimal problem solver written as a MATLAB toolbox with mixed-language programming (C, Fortran, Matlab, Simulink). This first paper introduces how to make RIOTS run under an embedded platform RP3B (Raspberry Pi 3 B) with Windows 10. We presented the system architecture and a complete demo on running RIOTS as the inner kernel for MPC, using a house made thermal control system based on Peltier modules.
{"title":"Embedded RIOTS: Model Predictive Control Towards Edge","authors":"J. Viola, Sina Dehghan, Y. Chen","doi":"10.1115/detc2019-97046","DOIUrl":"https://doi.org/10.1115/detc2019-97046","url":null,"abstract":"\u0000 RIOTS is a general purpose optimal problem solver written as a MATLAB toolbox with mixed-language programming (C, Fortran, Matlab, Simulink). This first paper introduces how to make RIOTS run under an embedded platform RP3B (Raspberry Pi 3 B) with Windows 10. We presented the system architecture and a complete demo on running RIOTS as the inner kernel for MPC, using a house made thermal control system based on Peltier modules.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124910891","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}
Zhenlong Wu, Jie Yuan, Donghai Li, Yali Xue, Y. Chen
Actuator rate limit deteriorates control performance with amplitude attenuation and phase delay, and may lead to system instability in process control. In this paper, great challenges for first-order plus time delay (FOPTD) systems are concerned. Based on the preliminary knowledge of the definition of rate limiter, the concept of closed-loop onset frequency with rate limiter and classic proportional-integral (PI) tuning rules, the rate limit effects on PI controller are analyzed by simulations. The results show that the rate limiter has significant influence on the stability regions of PI parameters which can be reduced greatly. Besides, PI tuning rules with the same robustness constraint can be obviously effected where Skogestad internal model (SIMC) tuning rule is more robust to the rate limit variation than that of maximize the integral gain (Åström) and robustness constrained optimization (DRO) tuning rule. These results can offer a guideline to tune PI parameters when actuators have non-ignorable rate limit for industrial applications.
{"title":"Actuator Rate Limit Effects on Proportional-Integral Controller for First-Order Plus Time-Delay Systems","authors":"Zhenlong Wu, Jie Yuan, Donghai Li, Yali Xue, Y. Chen","doi":"10.1115/detc2019-97662","DOIUrl":"https://doi.org/10.1115/detc2019-97662","url":null,"abstract":"\u0000 Actuator rate limit deteriorates control performance with amplitude attenuation and phase delay, and may lead to system instability in process control. In this paper, great challenges for first-order plus time delay (FOPTD) systems are concerned. Based on the preliminary knowledge of the definition of rate limiter, the concept of closed-loop onset frequency with rate limiter and classic proportional-integral (PI) tuning rules, the rate limit effects on PI controller are analyzed by simulations. The results show that the rate limiter has significant influence on the stability regions of PI parameters which can be reduced greatly. Besides, PI tuning rules with the same robustness constraint can be obviously effected where Skogestad internal model (SIMC) tuning rule is more robust to the rate limit variation than that of maximize the integral gain (Åström) and robustness constrained optimization (DRO) tuning rule. These results can offer a guideline to tune PI parameters when actuators have non-ignorable rate limit for industrial applications.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131290514","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}
Michele Bernardini, Alessandro Ferri, Lucia Migliorelli, S. Moccia, L. Romeo, S. Silvestri, Luca Tiano, A. Mancini
The Comet Assay is a well-known procedure employed to investigate the DNA damage and can be applied to several research areas such as environmental, medical and health sciences. User dependency and computation time effort represent some of the major drawbacks of the Comet Assay. Starting from this motivation, we applied a Machine Learning (ML) tool for discriminating DNA damage using a standard hand-crafted feature set. The experimental results demonstrate how the ML tool is able to objectively replicate human experts scoring (accuracy detection up to 92%) by solving the related binary task (i.e., controls vs damaged comets).
{"title":"Augmented Microscopy for DNA Damage Quantification: A Machine Learning Tool for Environmental, Medical and Health Sciences","authors":"Michele Bernardini, Alessandro Ferri, Lucia Migliorelli, S. Moccia, L. Romeo, S. Silvestri, Luca Tiano, A. Mancini","doi":"10.1115/detc2019-97902","DOIUrl":"https://doi.org/10.1115/detc2019-97902","url":null,"abstract":"\u0000 The Comet Assay is a well-known procedure employed to investigate the DNA damage and can be applied to several research areas such as environmental, medical and health sciences. User dependency and computation time effort represent some of the major drawbacks of the Comet Assay. Starting from this motivation, we applied a Machine Learning (ML) tool for discriminating DNA damage using a standard hand-crafted feature set. The experimental results demonstrate how the ML tool is able to objectively replicate human experts scoring (accuracy detection up to 92%) by solving the related binary task (i.e., controls vs damaged comets).","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"8 Suppl 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128847195","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}
This paper presents a Model Predictive Control (MPC) approach for longitudinal and lateral control of autonomous vehicles with a real-time local path planning algorithm. A heuristic graph search method (A* algorithm) combined with piecewise Bezier curve generation is implemented for obstacle avoidance in autonomous driving applications. Constant time headway control is implemented for a longitudinal motion to track lead vehicles and maintain a constant time gap. MPC is used to control the steering angle and the tractive force of the autonomous vehicle. Furthermore, a new method of developing Advanced Driver Assistance Systems (ADAS) algorithms and vehicle controllers using Model-In-the-Loop (MIL) testing is explored with the use of PreScan®. With PreScan®, various traffic scenarios are modeled and the sensor data are simulated by using physics-based sensor models, which are fed to the controller for data processing and motion planning. Obstacle detection and collision avoidance are demonstrated using the presented MPC controller.
{"title":"MPC-Based Control of Autonomous Vehicles With Localized Path Planning for Obstacle Avoidance Under Uncertainties","authors":"Sai Rajeev Devaragudi, Bo Chen","doi":"10.1115/detc2019-97712","DOIUrl":"https://doi.org/10.1115/detc2019-97712","url":null,"abstract":"\u0000 This paper presents a Model Predictive Control (MPC) approach for longitudinal and lateral control of autonomous vehicles with a real-time local path planning algorithm. A heuristic graph search method (A* algorithm) combined with piecewise Bezier curve generation is implemented for obstacle avoidance in autonomous driving applications. Constant time headway control is implemented for a longitudinal motion to track lead vehicles and maintain a constant time gap. MPC is used to control the steering angle and the tractive force of the autonomous vehicle. Furthermore, a new method of developing Advanced Driver Assistance Systems (ADAS) algorithms and vehicle controllers using Model-In-the-Loop (MIL) testing is explored with the use of PreScan®. With PreScan®, various traffic scenarios are modeled and the sensor data are simulated by using physics-based sensor models, which are fed to the controller for data processing and motion planning. Obstacle detection and collision avoidance are demonstrated using the presented MPC controller.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133363696","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}
T. Heikkilä, Janne Saukkoriipi, Jari M. Ahola, Tuomas Seppälä
Robot skills provide a way to model and reuse sensor and robot technologies in effective ways. Skills can integrate and synchronize robot actions and sensor data in a consistent way and provide a framework for configurable robot systems, enabling quick setups of applications. Skills and skill modeling can be used not only for representing the composition of sensor based robot tasks, but also for programming on-line such tasks. In this paper we will introduce a skill based approach for representing on-line programming of skill based tasks. We will also give a practical example for modelling and implementing on-line programming of a handling skill relying on use of object localization sensors.
{"title":"On-Line Programming of Robot Skills","authors":"T. Heikkilä, Janne Saukkoriipi, Jari M. Ahola, Tuomas Seppälä","doi":"10.1115/detc2019-97958","DOIUrl":"https://doi.org/10.1115/detc2019-97958","url":null,"abstract":"\u0000 Robot skills provide a way to model and reuse sensor and robot technologies in effective ways. Skills can integrate and synchronize robot actions and sensor data in a consistent way and provide a framework for configurable robot systems, enabling quick setups of applications. Skills and skill modeling can be used not only for representing the composition of sensor based robot tasks, but also for programming on-line such tasks. In this paper we will introduce a skill based approach for representing on-line programming of skill based tasks. We will also give a practical example for modelling and implementing on-line programming of a handling skill relying on use of object localization sensors.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122636541","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}
L. Carbonari, S. Brillarelli, M. Palpacelli, M. Callegari
This paper is focused on the analysis of an elastodynamic model, typically referred to single-link flexible manipulators, when it is extended to multibody systems with closed-loop kinematic chains subject to vibrations, caused by the slenderness of their mechanical structure together with severe dynamic working conditions. The work is aimed at analyzing the relationship between the degree of accuracy of the proposed elastodynamic model, compared with more complete but time consuming models developed with software, and the time required for its computation, with the final aim of guiding its implementation in real-time control algorithms. Notwithstanding the study is proposed for parallel kinematic machines, the results are also valid for serial kinematic chains.
{"title":"Analysis of a Multibody Elastodynamic Model for Closed-Loop Kinematic Mechanisms","authors":"L. Carbonari, S. Brillarelli, M. Palpacelli, M. Callegari","doi":"10.1115/detc2019-97901","DOIUrl":"https://doi.org/10.1115/detc2019-97901","url":null,"abstract":"\u0000 This paper is focused on the analysis of an elastodynamic model, typically referred to single-link flexible manipulators, when it is extended to multibody systems with closed-loop kinematic chains subject to vibrations, caused by the slenderness of their mechanical structure together with severe dynamic working conditions. The work is aimed at analyzing the relationship between the degree of accuracy of the proposed elastodynamic model, compared with more complete but time consuming models developed with software, and the time required for its computation, with the final aim of guiding its implementation in real-time control algorithms. Notwithstanding the study is proposed for parallel kinematic machines, the results are also valid for serial kinematic chains.","PeriodicalId":166402,"journal":{"name":"Volume 9: 15th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123128016","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：