Pub Date : 2007-09-01DOI: 10.2316/Journal.206.2007.4.206-2992
Manjunath Aradhya, G. Kumar, P. Shivakumara
Skew angle estimation is essential to enhance the accuracy of optical character recognition (OCR) system. In this paper we present a new boundary growing (BG) and nearest neighbor clustering (NNC) to estimate accurate skew angle for the scanned documents. The BG extracts the boundary characters present in each text line of the document and extracts uppermost, lowermost and centroid coordinates of character components of the scanned document image. The NNC helps us in clustering the characters which is presented due to additional modifiers-characters that are usually present in the South Indian scripts. The extracted coordinates are subjected to moments to estimate skew angle of the document image. Several experiments have been conducted on various types of documents such as documents containing South Indian scripts, English documents, journals, textbook, text with picture, text with tables, text with graphs, different languages, noisy images and document with different fonts, documents with different resolutions, to reveal the robustness of the proposed method. The experimental results revealed that the proposed method is accurate compared to the results of well-known existing methods.
{"title":"An Accurate and Efficient skew estimation Technique for South Indian Documents: a New boundary Growing and Nearest Neighbor Clustering Based Approach","authors":"Manjunath Aradhya, G. Kumar, P. Shivakumara","doi":"10.2316/Journal.206.2007.4.206-2992","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.4.206-2992","url":null,"abstract":"Skew angle estimation is essential to enhance the accuracy of optical character recognition (OCR) system. In this paper we present a new boundary growing (BG) and nearest neighbor clustering (NNC) to estimate accurate skew angle for the scanned documents. The BG extracts the boundary characters present in each text line of the document and extracts uppermost, lowermost and centroid coordinates of character components of the scanned document image. The NNC helps us in clustering the characters which is presented due to additional modifiers-characters that are usually present in the South Indian scripts. The extracted coordinates are subjected to moments to estimate skew angle of the document image. Several experiments have been conducted on various types of documents such as documents containing South Indian scripts, English documents, journals, textbook, text with picture, text with tables, text with graphs, different languages, noisy images and document with different fonts, documents with different resolutions, to reveal the robustness of the proposed method. The experimental results revealed that the proposed method is accurate compared to the results of well-known existing methods.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129721214","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 : 2007-06-01DOI: 10.2316/Journal.206.2007.3.206-3034
Zengshi Chen
This paper examines the dynamics and control of the humanoid double support stance (DSS) leap in the air and the subsequent stable landing. A complete model of a five-link biped standing on flat ground is considered in four phases: the take-off phase, the flight phase, the landing phase with impact, and the standing-up phase. Based on the presented dynamic formulation, an integral sliding mode control strategy is developed to track the reference motion, obtained by experimental recording of humans executing the DSS leap. The stability, finite-time convergence and robustness of the system are analyzed, and verified by computer simulation. The predicted ground reaction force (GRF) profiles are in agreement with experimental recording of the GRFs. In particular, the predictions capture the short duration, and large amplitudes of the GRFs upon impact as well as the burst of high energy required during the take-off phase.
{"title":"Integral sliding Mode Control of a bipedal Leap","authors":"Zengshi Chen","doi":"10.2316/Journal.206.2007.3.206-3034","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.3.206-3034","url":null,"abstract":"This paper examines the dynamics and control of the humanoid double support stance (DSS) leap in the air and the subsequent stable landing. A complete model of a five-link biped standing on flat ground is considered in four phases: the take-off phase, the flight phase, the landing phase with impact, and the standing-up phase. Based on the presented dynamic formulation, an integral sliding mode control strategy is developed to track the reference motion, obtained by experimental recording of humans executing the DSS leap. The stability, finite-time convergence and robustness of the system are analyzed, and verified by computer simulation. The predicted ground reaction force (GRF) profiles are in agreement with experimental recording of the GRFs. In particular, the predictions capture the short duration, and large amplitudes of the GRFs upon impact as well as the burst of high energy required during the take-off phase.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"460 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125807947","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 : 2007-06-01DOI: 10.2316/Journal.206.2007.3.206-2957
A. Khamis, M. Kamel, M. Salichs
{"title":"Human-robot Interfaces for Social Interaction","authors":"A. Khamis, M. Kamel, M. Salichs","doi":"10.2316/Journal.206.2007.3.206-2957","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.3.206-2957","url":null,"abstract":"","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124702253","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 : 2007-06-01DOI: 10.2316/Journal.206.2007.3.206-3011
S. Daroogheha, T. Radhakrishnan
The development of a compact and lightweight gripper suitable for a mini mobile robot for field applications poses many challenges. This is because conventional gripper actuation methods may be infeasible due to their size, weight and power requirements. This study focuses on the development of a suitable linkage mechanism for such a mini gripper, using two different actuation methods. The first design investigates the use of shape memory alloy (SMA) springs as a newer method for the gripper actuation. For comparison, the second design is developed using a more conventional, servomotor-based actuation. The design of the SMA springs used in the first gripper, and the kinematic analysis for both gripper designs, are presented. Prototypes of both designs were built and tested, and the results are also shown. Additionally, an accuracy analysis involving the gripper mechanism's tolerances and clearances is developed for both grippers, and a tolerance allocation technique to facilitate such gripper designs is also presented. The study shows that SMA spring actuated grippers hold promise for certain applications and should be considered in the design of mini mobile robot devices.
{"title":"An Analysis for a Mini robot gripper using SMA Springs","authors":"S. Daroogheha, T. Radhakrishnan","doi":"10.2316/Journal.206.2007.3.206-3011","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.3.206-3011","url":null,"abstract":"The development of a compact and lightweight gripper suitable for a mini mobile robot for field applications poses many challenges. This is because conventional gripper actuation methods may be infeasible due to their size, weight and power requirements. This study focuses on the development of a suitable linkage mechanism for such a mini gripper, using two different actuation methods. The first design investigates the use of shape memory alloy (SMA) springs as a newer method for the gripper actuation. For comparison, the second design is developed using a more conventional, servomotor-based actuation. The design of the SMA springs used in the first gripper, and the kinematic analysis for both gripper designs, are presented. Prototypes of both designs were built and tested, and the results are also shown. Additionally, an accuracy analysis involving the gripper mechanism's tolerances and clearances is developed for both grippers, and a tolerance allocation technique to facilitate such gripper designs is also presented. The study shows that SMA spring actuated grippers hold promise for certain applications and should be considered in the design of mini mobile robot devices.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127004484","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 : 2007-06-01DOI: 10.2316/Journal.206.2007.3.206-2829
Jose Luis Meza, V. Santibáñez, Ricardo Campa
This paper deals with the problem of estimation of the domain of attraction for the linear Proportional Integral Derivative (PID) regulator of robot manipulators. We first recall a simple semiglobal asymptotic stability analysis, which is one of the simplest found in the literature; then, based on such analysis we obtain an estimate of the domain of attraction in terms of the PID controller gains, allowing to know, in an explicit way, the radius of such an estimate of the region of attraction. To the best of the authors' knowledge, for the classical linear PID regulator of robot manipulators, this is the first paper that explicitly parameterizes the range of attraction of the goal position in terms of the proportional, derivative and integral gain matrices. As a consequence, we also propose a tuning procedure which allows to ensure asymptotic stability for a given initial conditions. Finally, as a way of testing this tuning procedure in a real application, we accomplish some experiments in a direct-drive robot arm.
{"title":"An estimate of the Domain of attraction for the PID regulator of manipulators","authors":"Jose Luis Meza, V. Santibáñez, Ricardo Campa","doi":"10.2316/Journal.206.2007.3.206-2829","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.3.206-2829","url":null,"abstract":"This paper deals with the problem of estimation of the domain of attraction for the linear Proportional Integral Derivative (PID) regulator of robot manipulators. We first recall a simple semiglobal asymptotic stability analysis, which is one of the simplest found in the literature; then, based on such analysis we obtain an estimate of the domain of attraction in terms of the PID controller gains, allowing to know, in an explicit way, the radius of such an estimate of the region of attraction. To the best of the authors' knowledge, for the classical linear PID regulator of robot manipulators, this is the first paper that explicitly parameterizes the range of attraction of the goal position in terms of the proportional, derivative and integral gain matrices. As a consequence, we also propose a tuning procedure which allows to ensure asymptotic stability for a given initial conditions. Finally, as a way of testing this tuning procedure in a real application, we accomplish some experiments in a direct-drive robot arm.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123887012","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 : 2007-06-01DOI: 10.2316/Journal.206.2007.3.206-2959
C. S. Bonaventura, K. Jablokow, K. Buffinton
This paper presents an efficient modular algorithm for the dynamic simulation of systems of multiple flexible robots with multiple concurrent constraints. This research represents an important extension of previous work in the modular dynamic simulation of complex rigid-body systems. In addition to a summary of the algorithm, the treatment of potentially critical nonlinear strain and kinematic effects is also discussed. The algorithm is validated through several examples, including both series and parallel robot configurations.
{"title":"A Modular Algorithm for the Dynamics of Multiple Flexible robots","authors":"C. S. Bonaventura, K. Jablokow, K. Buffinton","doi":"10.2316/Journal.206.2007.3.206-2959","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.3.206-2959","url":null,"abstract":"This paper presents an efficient modular algorithm for the dynamic simulation of systems of multiple flexible robots with multiple concurrent constraints. This research represents an important extension of previous work in the modular dynamic simulation of complex rigid-body systems. In addition to a summary of the algorithm, the treatment of potentially critical nonlinear strain and kinematic effects is also discussed. The algorithm is validated through several examples, including both series and parallel robot configurations.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132919854","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 : 2007-06-01DOI: 10.2316/Journal.206.2007.3.206-2922
A. Lotfazar, M. Eghtesad
In this paper, dynamic equations of motion of a rigid-link non-redundant n-DOF robot manipulator consisting of mechanical arms, all with revolute joints and electrical actuators are considered and application of passivity-based and integrator backstepping techniques for trajectory tracking of the robot in presence of disturbance, friction and uncertainty is studied. One of the main advantages of the backstepping control techniques is that they impose desired properties of stability, initially by fixing the candidate Lyapunov functions, then by calculating the storage functions, stabilizing functions and feedback control laws in a recursive way. Simulation results of applying these schemes show the ability of backstepping methods in trajectory tracking in presence of disturbance, friction and parameter uncertainty. Comparison of simulation results of the two backstepping methods shows that passivity based with respect to integrator based method has more smooth control commands and better trajectory tracking by using passivity properties of the robot and by using some weighting matrices in its algorithm.
{"title":"Application and Comparison of passivity-Based and integrator backstepping Control Methods for trajectory Tracking of Rigid-Link robot manipulators Incorporating Motor Dynamics","authors":"A. Lotfazar, M. Eghtesad","doi":"10.2316/Journal.206.2007.3.206-2922","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.3.206-2922","url":null,"abstract":"In this paper, dynamic equations of motion of a rigid-link non-redundant n-DOF robot manipulator consisting of mechanical arms, all with revolute joints and electrical actuators are considered and application of passivity-based and integrator backstepping techniques for trajectory tracking of the robot in presence of disturbance, friction and uncertainty is studied. \u0000 \u0000One of the main advantages of the backstepping control techniques is that they impose desired properties of stability, initially by fixing the candidate Lyapunov functions, then by calculating the storage functions, stabilizing functions and feedback control laws in a recursive way. \u0000 \u0000Simulation results of applying these schemes show the ability of backstepping methods in trajectory tracking in presence of disturbance, friction and parameter uncertainty. Comparison of simulation results of the two backstepping methods shows that passivity based with respect to integrator based method has more smooth control commands and better trajectory tracking by using passivity properties of the robot and by using some weighting matrices in its algorithm.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121632860","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 : 2007-06-01DOI: 10.2316/Journal.206.2007.3.206-2949
Zhiqiang Li, Chenguang Yang, Jiangong Gu
In this paper, neuro-adaptive force/motion control of mobile manipulators in the presence of unknown dynamic model and uncertain constraints is studied. The working surface is deformable, and the geometric and physical model of the surface is unknown. All contact forces are nonlinear and difficult to model. A neuro-based control with robust force/motion tracking performance for constrained robot manipulators is proposed. The control law is based on the philosophy of the parallel approach in two decoupled subspaces and utilizes an adaptive scheme to deal with the uncertain environmental constraints, disturbances, and unknown robotic dynamics. The wheeled mobile base is utilized to avoid the system's singularity. Stability conditions for control parameters are derived. Simulation results are presented to show the effectiveness of the proposed control, which performs better compared with model-based control.
{"title":"Neuro-Adaptive Compliant force/Motion Control of uncertain Constrained wheeled Mobile manipulators","authors":"Zhiqiang Li, Chenguang Yang, Jiangong Gu","doi":"10.2316/Journal.206.2007.3.206-2949","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.3.206-2949","url":null,"abstract":"In this paper, neuro-adaptive force/motion control of mobile manipulators in the presence of unknown dynamic model and uncertain constraints is studied. The working surface is deformable, and the geometric and physical model of the surface is unknown. All contact forces are nonlinear and difficult to model. A neuro-based control with robust force/motion tracking performance for constrained robot manipulators is proposed. The control law is based on the philosophy of the parallel approach in two decoupled subspaces and utilizes an adaptive scheme to deal with the uncertain environmental constraints, disturbances, and unknown robotic dynamics. The wheeled mobile base is utilized to avoid the system's singularity. Stability conditions for control parameters are derived. Simulation results are presented to show the effectiveness of the proposed control, which performs better compared with model-based control.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130042106","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 : 2007-03-01DOI: 10.2316/Journal.206.2007.2.206-2896
S. Timar, R. Farouki, Casey L. Boyadjieff
The authors consider the problem of specifying the feedrate variation along a curved path, that yields the minimum traversal time for a multi-axis CNC machine subject to given bounds on the feasible velocity and acceleration along each axis. The torque-speed characteristics of the axis drive motors are first discussed, and are used to determine constraints on the velocity and acceleration for each axis. For a path specified by a polynomial parametric curve r(ξ), it is shown that (the square of) the time-optimal feedrate can be determined as a piecewise-rational function of the curve parameter ξ, with break-points that correspond to the roots of certain polynomials. In general, each feedrate segment is characterized by the saturation of either velocity or acceleration on one machine axis at each instant throughout the motion. The feedrate function admits a real-time interpolator algorithm that can drive the machine from the analytic curve description, eliminating the need for piecewise-linear/circular G code approximations. The theoretical and computational aspects of such time-optimal feedrates are presented, along with experimental results from implementation on a three-axis CNC mill driven by an open-architecture software controller. Compared to prior time-optimal feedrate algorithms (based on acceleration bounds only), the new algorithms give physically valid feedrates at high speeds, where the motor voltage ratings become a limiting factor.
{"title":"Time-Optimal feedrates along Curved Paths for Cartesian CNC Machines with prescribed Bounds on Axis velocities and Accelerations","authors":"S. Timar, R. Farouki, Casey L. Boyadjieff","doi":"10.2316/Journal.206.2007.2.206-2896","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.2.206-2896","url":null,"abstract":"The authors consider the problem of specifying the feedrate variation along a curved path, that yields the minimum traversal time for a multi-axis CNC machine subject to given bounds on the feasible velocity and acceleration along each axis. The torque-speed characteristics of the axis drive motors are first discussed, and are used to determine constraints on the velocity and acceleration for each axis. For a path specified by a polynomial parametric curve r(ξ), it is shown that (the square of) the time-optimal feedrate can be determined as a piecewise-rational function of the curve parameter ξ, with break-points that correspond to the roots of certain polynomials. In general, each feedrate segment is characterized by the saturation of either velocity or acceleration on one machine axis at each instant throughout the motion. The feedrate function admits a real-time interpolator algorithm that can drive the machine from the analytic curve description, eliminating the need for piecewise-linear/circular G code approximations. The theoretical and computational aspects of such time-optimal feedrates are presented, along with experimental results from implementation on a three-axis CNC mill driven by an open-architecture software controller. Compared to prior time-optimal feedrate algorithms (based on acceleration bounds only), the new algorithms give physically valid feedrates at high speeds, where the motor voltage ratings become a limiting factor.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115847272","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 : 2007-03-01DOI: 10.2316/Journal.206.2007.2.206-2939
P. Herman
The paper presents optimization of the generalized velocity components (GVC) in order to obtain the energy efficient profile. The GVC arise from decomposition of the system mass matrix and the corresponding equations of motion are first-order. The obtained optimal quantities show some properties of the system that are not observable if the system is described using the second-order differential equations of motion. As a result, an insight into the system dynamics can be given and nonlinearity evaluation and reduction is possible. The presented approach was tested analytically and in simulation on a 2 DOF planar mechanical system.
{"title":"Use of Optimal quasi- velocity Trajectories","authors":"P. Herman","doi":"10.2316/Journal.206.2007.2.206-2939","DOIUrl":"https://doi.org/10.2316/Journal.206.2007.2.206-2939","url":null,"abstract":"The paper presents optimization of the generalized velocity components (GVC) in order to obtain the energy efficient profile. The GVC arise from decomposition of the system mass matrix and the corresponding equations of motion are first-order. The obtained optimal quantities show some properties of the system that are not observable if the system is described using the second-order differential equations of motion. As a result, an insight into the system dynamics can be given and nonlinearity evaluation and reduction is possible. The presented approach was tested analytically and in simulation on a 2 DOF planar mechanical system.","PeriodicalId":206015,"journal":{"name":"Int. J. Robotics Autom.","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115695817","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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