Pub Date : 2022-02-14DOI: 10.15406/iratj.2023.09.00256
A. Krasinskiy
The level of development of actuator technology and the element base and software of control loops of modern automatic devices makes it possible to use in technical practice complex control algorithms based on the results of mathematical control theory, including with incomplete information about the state. The effectiveness of such algorithms is determined by the presence of an adequate mathematical model of the device under study. For such a widespread class of automatic devices as manipulators with parallel kinematics, the problem of developing methods for creating mathematical models that allow taking into account nonlinear effects, despite the efforts of numerous researchers, remains relevant. To a large extent, the complexity of modeling the dynamics of this class of automatic devices is associated with the presence of parallel kinematic chains, which leads to the need to apply the results of analytical mechanics of non-free systems. In this section of theoretical mechanics, several rigorous methods have been developed, as a result of which mathematical models of different dimensions are obtained with different levels of complexity of the algorithms for their derivation and study. This leads to the need for a critical analysis of both the methods themselves and their possible application in technical practice. In this paper, the main algorithms for obtaining mathematical models of the dynamics of systems with geometric constraints are presented in detail and some comparative analysis of their application to modeling the dynamics of manipulators with parallel kinematics is carried out.
{"title":"On the methods of analytical mechanics for mathematical modeling of the dynamics of non-free systems and some variants of their application to the dynamics of parallel manipulators","authors":"A. Krasinskiy","doi":"10.15406/iratj.2023.09.00256","DOIUrl":"https://doi.org/10.15406/iratj.2023.09.00256","url":null,"abstract":"The level of development of actuator technology and the element base and software of control loops of modern automatic devices makes it possible to use in technical practice complex control algorithms based on the results of mathematical control theory, including with incomplete information about the state. The effectiveness of such algorithms is determined by the presence of an adequate mathematical model of the device under study. For such a widespread class of automatic devices as manipulators with parallel kinematics, the problem of developing methods for creating mathematical models that allow taking into account nonlinear effects, despite the efforts of numerous researchers, remains relevant. To a large extent, the complexity of modeling the dynamics of this class of automatic devices is associated with the presence of parallel kinematic chains, which leads to the need to apply the results of analytical mechanics of non-free systems. In this section of theoretical mechanics, several rigorous methods have been developed, as a result of which mathematical models of different dimensions are obtained with different levels of complexity of the algorithms for their derivation and study. This leads to the need for a critical analysis of both the methods themselves and their possible application in technical practice. In this paper, the main algorithms for obtaining mathematical models of the dynamics of systems with geometric constraints are presented in detail and some comparative analysis of their application to modeling the dynamics of manipulators with parallel kinematics is carried out.","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114680352","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 : 2022-01-20DOI: 10.15406/iratj.2022.08.00237
Elsayed Ahmed Elnashar
{"title":"Applications of mechatronics opportunities in textiles","authors":"Elsayed Ahmed Elnashar ","doi":"10.15406/iratj.2022.08.00237","DOIUrl":"https://doi.org/10.15406/iratj.2022.08.00237","url":null,"abstract":"","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133803264","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 : 2022-01-13DOI: 10.15406/iratj.2022.08.00236
Adas Pereira Vitall, Rogério Clemente, Arnaldo Ortiz, Rosário A, João Maurício
{"title":"Industrial robots integration based in object location and component inspection in industry 4.0 using vision guided robot (VGR)","authors":"Adas Pereira Vitall, Rogério Clemente, Arnaldo Ortiz, Rosário A, João Maurício","doi":"10.15406/iratj.2022.08.00236","DOIUrl":"https://doi.org/10.15406/iratj.2022.08.00236","url":null,"abstract":"","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116843515","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 : 2022-01-09DOI: 10.15406/iratj.2023.09.00254
D. Watabe, M. Wada, Nobumitu Shimizu, Tastuma Ohkubo
Amphibious buses are extensively used worldwide for transporting people to and from tourist attractions across water and land. Although numerous studies on self-driving technologies have been reported, research on the automatic operation and navigation of an amphibious vehicle has been sparse; moreover, owing to the size of the amphibious vehicles, automatic transport of multiple people is not possible. Therefore, in this study, we attempted to realize unmanned operation of a sightseeing amphibious bus for 45 passengers. The bus was outfitted with a by-wire system. On the vessel side, an actuator, similar to that used in JOY cars, was installed to turn the captain’s steering wheel. We also developed a software for the automatic operation and navigation of the bus. The relationship between the car’s steering-wheel angle and the front-tire angles is linear, whereas that between the captain’s steering-wheel angle and the vessel’s rudder-plate angle is not (and was approximated with a sixth-order polynomial). Furthermore, Autoware—a leading autonomous-driving software utilizing model-based predictive control algorithms to control the steering wheel of automobiles—was employed in this work. These algorithms were altered using Nomoto’s KT vessel model equation to improve the accuracy of vessel-path tracking. To the best of our knowledge, till date, no studies have documented the functioning of self-driving vessels using predictive controls based on Nomoto’s KT vessel model equation. In accordance with the vessel navigation rules based on the Autoware obstacle avoidance logic, LiDAR, cameras, and sonars were employed to detect obstructions and give-way paths. Thus, we successfully demonstrated the working of world's first self-driving amphibious bus, with automated controls for entering/exiting water and during give-way operations.
{"title":"World’s first self-driving amphibious bus","authors":"D. Watabe, M. Wada, Nobumitu Shimizu, Tastuma Ohkubo","doi":"10.15406/iratj.2023.09.00254","DOIUrl":"https://doi.org/10.15406/iratj.2023.09.00254","url":null,"abstract":"Amphibious buses are extensively used worldwide for transporting people to and from tourist attractions across water and land. Although numerous studies on self-driving technologies have been reported, research on the automatic operation and navigation of an amphibious vehicle has been sparse; moreover, owing to the size of the amphibious vehicles, automatic transport of multiple people is not possible. Therefore, in this study, we attempted to realize unmanned operation of a sightseeing amphibious bus for 45 passengers. The bus was outfitted with a by-wire system. On the vessel side, an actuator, similar to that used in JOY cars, was installed to turn the captain’s steering wheel. We also developed a software for the automatic operation and navigation of the bus. The relationship between the car’s steering-wheel angle and the front-tire angles is linear, whereas that between the captain’s steering-wheel angle and the vessel’s rudder-plate angle is not (and was approximated with a sixth-order polynomial). Furthermore, Autoware—a leading autonomous-driving software utilizing model-based predictive control algorithms to control the steering wheel of automobiles—was employed in this work. These algorithms were altered using Nomoto’s KT vessel model equation to improve the accuracy of vessel-path tracking. To the best of our knowledge, till date, no studies have documented the functioning of self-driving vessels using predictive controls based on Nomoto’s KT vessel model equation. In accordance with the vessel navigation rules based on the Autoware obstacle avoidance logic, LiDAR, cameras, and sonars were employed to detect obstructions and give-way paths. Thus, we successfully demonstrated the working of world's first self-driving amphibious bus, with automated controls for entering/exiting water and during give-way operations.","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125740105","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 : 2021-12-02DOI: 10.15406/iratj.2021.07.00235
P. Lohmander
A general spatial fire brigade unit network density optimization problem has been solved. The distance to a particular road, from a fire station, is approximated as a continuous variable. It is proved, via integral convolution, that the probability density function of the total travel time, PDFT, is triangular. The size of the fire, when it stopped, is a function of the time it takes until the fire brigade reaches the fire location. An explicit continuous function for the expected total cost per square kilometer, based on the cost per fire station, the PDFT, the exponential fire cost function parameters, the distance between fire stations, and the speed of fire engines, is derived. It is proved that the optimal distance between fire brigade unit positions, OFD, which minimizes the total expected cost, is unique. Then, the OFDs are replaced by integers, OFDIs, for different parameter assumptions. In this process, also the optimal expected total costs are determined. It is proved that the OFD is a strictly decreasing function of the expected number of fires per area unit, a strictly increasing function of the speed of the fire engines, a strictly decreasing function of the parameters of the exponential fire cost function, and a strictly increasing function of the cost per fire station. These effects of parameter changes are also illustrated via graphs in the numerical section.
{"title":"Optimization of distance between fire stations: effects of fire ignition probabilities, fire engine speed and road limitations, property values and weather conditions","authors":"P. Lohmander","doi":"10.15406/iratj.2021.07.00235","DOIUrl":"https://doi.org/10.15406/iratj.2021.07.00235","url":null,"abstract":"A general spatial fire brigade unit network density optimization problem has been solved. The distance to a particular road, from a fire station, is approximated as a continuous variable. It is proved, via integral convolution, that the probability density function of the total travel time, PDFT, is triangular. The size of the fire, when it stopped, is a function of the time it takes until the fire brigade reaches the fire location. An explicit continuous function for the expected total cost per square kilometer, based on the cost per fire station, the PDFT, the exponential fire cost function parameters, the distance between fire stations, and the speed of fire engines, is derived. It is proved that the optimal distance between fire brigade unit positions, OFD, which minimizes the total expected cost, is unique. Then, the OFDs are replaced by integers, OFDIs, for different parameter assumptions. In this process, also the optimal expected total costs are determined. It is proved that the OFD is a strictly decreasing function of the expected number of fires per area unit, a strictly increasing function of the speed of the fire engines, a strictly decreasing function of the parameters of the exponential fire cost function, and a strictly increasing function of the cost per fire station. These effects of parameter changes are also illustrated via graphs in the numerical section.","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126152523","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 : 2021-11-19DOI: 10.15406/iratj.2021.07.00234
K. Pasha
In this paper, architecture for the robot arm and a mathematical model was suggested to simplify the inverse kinematics that describes the movement and orientation of this end-effector. Although this design contains eight degrees of freedom, all the angular displacements and velocities could be formulated as functions of the three coordinates of the end-effecter starting point. These three values are enough to set the end-effector at the desired point in the workspace, and with the desired orientation. The tip of the end-effecter could be equipped with a grabber or any attached manufacturing tool. To check the reliability of the introduced mathematical model, a simple model for the arm was built using aluminum beams. The joints are actuated by stepper motors that are controlled by a microprocessor. The model executed the positioning and orientation of the end-effector with an accuracy of about 93% of any traveled distance. This lack of accuracy may be accounted for by the low resolutions of the used motors. In this study, the positioning and orientation were only considered, and future work is required for the analysis of loads and power capacities
{"title":"A suggested simple design and inverse kinematics for a multi-degrees-of-freedom robot arm","authors":"K. Pasha","doi":"10.15406/iratj.2021.07.00234","DOIUrl":"https://doi.org/10.15406/iratj.2021.07.00234","url":null,"abstract":"In this paper, architecture for the robot arm and a mathematical model was suggested to simplify the inverse kinematics that describes the movement and orientation of this end-effector. Although this design contains eight degrees of freedom, all the angular displacements and velocities could be formulated as functions of the three coordinates of the end-effecter starting point. These three values are enough to set the end-effector at the desired point in the workspace, and with the desired orientation. The tip of the end-effecter could be equipped with a grabber or any attached manufacturing tool. To check the reliability of the introduced mathematical model, a simple model for the arm was built using aluminum beams. The joints are actuated by stepper motors that are controlled by a microprocessor. The model executed the positioning and orientation of the end-effector with an accuracy of about 93% of any traveled distance. This lack of accuracy may be accounted for by the low resolutions of the used motors. In this study, the positioning and orientation were only considered, and future work is required for the analysis of loads and power capacities","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123049013","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 : 2021-11-16DOI: 10.15406/iratj.2021.07.00233
R. Usubamatov, A. Arzybaev
New studies of the dynamics of rotating objects have shown the origin of their gyroscopic effects is more sophisticated than presented in publications. Their rotating mass acting on bodies generates the system of the kinetically interrelated inertial torques. The method for developing mathematical models for inertial torques of the spinning objects shows their dependencies on geometries. The inertial torques generated by the disc, ring, paraboloid, and others have confirmed this statement. The derived analytical method presents a new direction for the dynamics of classical mechanics. The several inertial torqueses acting on any movable spinning objects in space were unknown until recent times. The gyroscopic effects of rotating objects in engineering and a new method for computing their inertial torques are the challenges for researchers. The novelty of this manuscript is the mathematical models for the inertial torques generated by the rotating mass acting on the spinning solid and hollow sphere.
{"title":"Inertial torques acting on a spinning sphere","authors":"R. Usubamatov, A. Arzybaev","doi":"10.15406/iratj.2021.07.00233","DOIUrl":"https://doi.org/10.15406/iratj.2021.07.00233","url":null,"abstract":"New studies of the dynamics of rotating objects have shown the origin of their gyroscopic effects is more sophisticated than presented in publications. Their rotating mass acting on bodies generates the system of the kinetically interrelated inertial torques. The method for developing mathematical models for inertial torques of the spinning objects shows their dependencies on geometries. The inertial torques generated by the disc, ring, paraboloid, and others have confirmed this statement. The derived analytical method presents a new direction for the dynamics of classical mechanics. The several inertial torqueses acting on any movable spinning objects in space were unknown until recent times. The gyroscopic effects of rotating objects in engineering and a new method for computing their inertial torques are the challenges for researchers. The novelty of this manuscript is the mathematical models for the inertial torques generated by the rotating mass acting on the spinning solid and hollow sphere.","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116924975","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 : 2021-08-26DOI: 10.15406/iratj.2021.07.00228
M. V. Levskii
The original control problem of optimal reorientation from a state of rest to a state of rest is considered and solved. The control function is torque vector. Problem of optimal control is investigated in detail for statement when control is restricted and the used functional of optimality includes kinematical rotary energy and time of maneuver. For solving and synthesis of the optimal control program, the quaternion method and the Pontryagin’s maximum principle are applied. Analytic solution of the proposed problem is presented basing on the differential equation connecting the angular velocity vector and quaternion of spacecraft attitude. It is shown that a chosen criterion of optimality provides a turn of a spacecraft with rotation energy which does not exceed the required value. This property of proposed control increases safety of flight. The time-optimal problem was solved also. The control law is formulated in the form of an explicit dependence of the control variables on the phase coordinates. All key expressions and equations are written in quaternion form which is convenient for onboard realization and implementation. The analysis of the special control regime of the spacecraft was made. Analytical formulas were written for duration of acceleration and braking. For specific cases of spacecraft configurations (dynamically symmetric spacecraft and spheric-symmetrical spacecraft as particular cases), complete solution of optimal control problem in closed form is given. Numerical example and the results of mathematical simulation for spacecraft motion under optimal control are demonstrated. This data supplements the made theoretical descriptions, and illustrates the practical feasibility of the designed algorithm for controlling the spatial orientation of the spacecraft showing reorientation process in visual form.
{"title":"Optimization problem of attitude control of a spacecraft with bounded rotary energy using quaternions","authors":"M. V. Levskii","doi":"10.15406/iratj.2021.07.00228","DOIUrl":"https://doi.org/10.15406/iratj.2021.07.00228","url":null,"abstract":"The original control problem of optimal reorientation from a state of rest to a state of rest is considered and solved. The control function is torque vector. Problem of optimal control is investigated in detail for statement when control is restricted and the used functional of optimality includes kinematical rotary energy and time of maneuver. For solving and synthesis of the optimal control program, the quaternion method and the Pontryagin’s maximum principle are applied. Analytic solution of the proposed problem is presented basing on the differential equation connecting the angular velocity vector and quaternion of spacecraft attitude. It is shown that a chosen criterion of optimality provides a turn of a spacecraft with rotation energy which does not exceed the required value. This property of proposed control increases safety of flight. The time-optimal problem was solved also. The control law is formulated in the form of an explicit dependence of the control variables on the phase coordinates. All key expressions and equations are written in quaternion form which is convenient for onboard realization and implementation. The analysis of the special control regime of the spacecraft was made. Analytical formulas were written for duration of acceleration and braking. For specific cases of spacecraft configurations (dynamically symmetric spacecraft and spheric-symmetrical spacecraft as particular cases), complete solution of optimal control problem in closed form is given. Numerical example and the results of mathematical simulation for spacecraft motion under optimal control are demonstrated. This data supplements the made theoretical descriptions, and illustrates the practical feasibility of the designed algorithm for controlling the spatial orientation of the spacecraft showing reorientation process in visual form.","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125830193","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 : 2021-07-23DOI: 10.15406/iratj.2021.07.00277
Rachit Aggarwal, Mrinal Kumar, Rachel E Keil, Anil V. Rao
The problem of optimal path planning through narrow spaces in an unstructured environment is considered. The optimal path planning problem for a Dubins agent is formulated as a chance-constrained optimal control problem (CCOCP), wherein the uncertainty in obstacle boundaries is modelled using standard probability distributions. The chance constraints are transformed to deterministic equivalents using the inverse cumulative distribution function and subsequently incorporated into a deterministic optimal control problem. Due to multiple convex sub-regions introduced by the obstacles, the initial guess provided to optimal control solver is crucial for computation time and optimality of the solution. A constrained Delaunay triangulation mesh based approach is developed that ensures the initial guess to lie in the optimal sub-convex region. Finally, off-the-shelf software is used to transcribe the optimal control problem to a nonlinear program (NLP) using Gaussian quadrature orthogonal collocation and solved to obtain an optimal path that conforms to system dynamics. By varying the upper bound on probability of obstacle collision, a family of solutions is generated, parameterized by the risk associated with each solution. This approach enables discovery of special “keyhole trajectories” that can provide significant cost savings in a tightly-spaced obstacle field. Merits of this approach are illustrated by comparing it with the traditional bounded uncertainty approach.
{"title":"Chance-constrained path planning in narrow spaces for a dubins vehicle","authors":"Rachit Aggarwal, Mrinal Kumar, Rachel E Keil, Anil V. Rao","doi":"10.15406/iratj.2021.07.00277","DOIUrl":"https://doi.org/10.15406/iratj.2021.07.00277","url":null,"abstract":"The problem of optimal path planning through narrow spaces in an unstructured environment is considered. The optimal path planning problem for a Dubins agent is formulated as a chance-constrained optimal control problem (CCOCP), wherein the uncertainty in obstacle boundaries is modelled using standard probability distributions. The chance constraints are transformed to deterministic equivalents using the inverse cumulative distribution function and subsequently incorporated into a deterministic optimal control problem. Due to multiple convex sub-regions introduced by the obstacles, the initial guess provided to optimal control solver is crucial for computation time and optimality of the solution. A constrained Delaunay triangulation mesh based approach is developed that ensures the initial guess to lie in the optimal sub-convex region. Finally, off-the-shelf software is used to transcribe the optimal control problem to a nonlinear program (NLP) using Gaussian quadrature orthogonal collocation and solved to obtain an optimal path that conforms to system dynamics. By varying the upper bound on probability of obstacle collision, a family of solutions is generated, parameterized by the risk associated with each solution. This approach enables discovery of special “keyhole trajectories” that can provide significant cost savings in a tightly-spaced obstacle field. Merits of this approach are illustrated by comparing it with the traditional bounded uncertainty approach.","PeriodicalId":346234,"journal":{"name":"International Robotics & Automation Journal","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133029042","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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