Pub Date : 1995-08-05DOI: 10.1109/IROS.1995.525828
T. Morita, S. Sugano
In order to realize constraint tasks by a manipulator, it is effective to adjust the joint impedance to the appropriate value. Most of the previous studies use the active force control method that uses information from force sensors. Using this method, the performances are limited by the responses of the servo systems, the non-linear characteristics of the force sensors and the dynamics of the manipulator. The object of this study is to adjust the joint impedance of the manipulator to an ideal degree by a mechanism which consists of a spring and a damper. In a previous study, the authors proposed a compliance adjustment method using the spring mechanism, the structure and control of the pseudo-damper system, and simple control algorithms for the coordinated system. In this paper, the authors discuss the evaluation of the effect of these mechanisms and the control method using the 1-DOF Arm Model which was newly developed as a base model to build a multiple degrees of freedom manipulator.
{"title":"Development of one-DOF robot arm equipped with mechanical impedance adjuster","authors":"T. Morita, S. Sugano","doi":"10.1109/IROS.1995.525828","DOIUrl":"https://doi.org/10.1109/IROS.1995.525828","url":null,"abstract":"In order to realize constraint tasks by a manipulator, it is effective to adjust the joint impedance to the appropriate value. Most of the previous studies use the active force control method that uses information from force sensors. Using this method, the performances are limited by the responses of the servo systems, the non-linear characteristics of the force sensors and the dynamics of the manipulator. The object of this study is to adjust the joint impedance of the manipulator to an ideal degree by a mechanism which consists of a spring and a damper. In a previous study, the authors proposed a compliance adjustment method using the spring mechanism, the structure and control of the pseudo-damper system, and simple control algorithms for the coordinated system. In this paper, the authors discuss the evaluation of the effect of these mechanisms and the control method using the 1-DOF Arm Model which was newly developed as a base model to build a multiple degrees of freedom manipulator.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126364278","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 : 1995-08-05DOI: 10.1109/IROS.1995.525809
M. Langer, G. Dudek, S. Zucker
Addresses the problem of estimating 3D space occupancy using video imagery in the context of mobile robotics. A stationary robot observes a cluttered scene from a single viewpoint, and a second robot illuminates the scene from a sequence of directions thus producing a sequence of grey-level images. Differences of successive images are used to compute a sequence of shadowimages. The problem is to compute free space and occupied space from these shadowimages. Solutions to this problem are known for the special case of terrain scenes. The authors generalize these solutions to non-terrain scenes by making two key observations. First, there is a subset constraint on the shadowimages of a non-terrain scene, which allows the visible surfaces of a non-terrain scene to be recovered by a terrain-based technique. Second, the remaining regions of the shadowimages provide a conservative estimate of the occupied space hidden by these visible surfaces.
{"title":"Space occupancy using multiple shadowimages","authors":"M. Langer, G. Dudek, S. Zucker","doi":"10.1109/IROS.1995.525809","DOIUrl":"https://doi.org/10.1109/IROS.1995.525809","url":null,"abstract":"Addresses the problem of estimating 3D space occupancy using video imagery in the context of mobile robotics. A stationary robot observes a cluttered scene from a single viewpoint, and a second robot illuminates the scene from a sequence of directions thus producing a sequence of grey-level images. Differences of successive images are used to compute a sequence of shadowimages. The problem is to compute free space and occupied space from these shadowimages. Solutions to this problem are known for the special case of terrain scenes. The authors generalize these solutions to non-terrain scenes by making two key observations. First, there is a subset constraint on the shadowimages of a non-terrain scene, which allows the visible surfaces of a non-terrain scene to be recovered by a terrain-based technique. Second, the remaining regions of the shadowimages provide a conservative estimate of the occupied space hidden by these visible surfaces.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126392268","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 : 1995-08-05DOI: 10.1109/IROS.1995.526259
Y. Kitamura, Takaaki Tanaka, F. Kishino, M. Yachida
Proposes an efficient and simple method for finding a collision-free path and orientation for a rigid robot in a dynamic observable 3-D environment for unmanned aerial vehicles (UAVs). The method uses an octree for representing every object (robot and static/dynamic obstacles) in the environment without any distinction of the movability of objects; therefore, all objects are dealt with in the same way. The path of a robot from its starting position to the given goal with arbitrary motion (i.e., translation and rotation) in a 3-D environment is efficiently searched for in successive adjoining regions (octree white cells) by using the potential field generated from each black cell of the octree. The algorithm is simple, so it can easily be accelerated by using parallelization techniques. Experimental results obtained under several conditions, such as a point shaped robot and arbitrarily shaped robots in static/dynamic environments, are reported.
{"title":"3-D path planning in a dynamic environment using an octree and an artificial potential field","authors":"Y. Kitamura, Takaaki Tanaka, F. Kishino, M. Yachida","doi":"10.1109/IROS.1995.526259","DOIUrl":"https://doi.org/10.1109/IROS.1995.526259","url":null,"abstract":"Proposes an efficient and simple method for finding a collision-free path and orientation for a rigid robot in a dynamic observable 3-D environment for unmanned aerial vehicles (UAVs). The method uses an octree for representing every object (robot and static/dynamic obstacles) in the environment without any distinction of the movability of objects; therefore, all objects are dealt with in the same way. The path of a robot from its starting position to the given goal with arbitrary motion (i.e., translation and rotation) in a 3-D environment is efficiently searched for in successive adjoining regions (octree white cells) by using the potential field generated from each black cell of the octree. The algorithm is simple, so it can easily be accelerated by using parallelization techniques. Experimental results obtained under several conditions, such as a point shaped robot and arbitrarily shaped robots in static/dynamic environments, are reported.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125723908","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 : 1995-08-05DOI: 10.1109/IROS.1995.525836
T. Suehiro, K. Kitagaki
We have been developing a multi-agent robot control system for an intelligent robot which is an integration of many kinds of functional modules. The control system consists of multiple transputers and workstations. To support flexible and high speed communication between agents on the network, we have developed a router software. Using the router, the system realizes a very flexible robot control system which supports throughout of robot control, from the low level control such as servo control to the high level control such as motion planning. This paper describes the multi-agent robot control system with the router software, estimation of its communication performance and a multi-agent based implementation of task coordinate servo control of a direct drive manipulator: ETA3.
{"title":"A multi-agent based implementation of task coordinate servo for the DD manipulator: ETA3","authors":"T. Suehiro, K. Kitagaki","doi":"10.1109/IROS.1995.525836","DOIUrl":"https://doi.org/10.1109/IROS.1995.525836","url":null,"abstract":"We have been developing a multi-agent robot control system for an intelligent robot which is an integration of many kinds of functional modules. The control system consists of multiple transputers and workstations. To support flexible and high speed communication between agents on the network, we have developed a router software. Using the router, the system realizes a very flexible robot control system which supports throughout of robot control, from the low level control such as servo control to the high level control such as motion planning. This paper describes the multi-agent robot control system with the router software, estimation of its communication performance and a multi-agent based implementation of task coordinate servo control of a direct drive manipulator: ETA3.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121649736","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 : 1995-08-05DOI: 10.1109/IROS.1995.526145
J. Son, M. Cutkosky, R. Howe
This paper presents an experimental comparison of tactile array versus force-torque sensing for localizing contact during manipulation. The manipulation tasks involved rotating and translating objects using a planar two fingered manipulator. A pin and a box were selected as limiting cases of point and line contact against a cylindrical robot finger tip. Force-torque contact sensing results suffered from difficulties in calibration, transient forces, and low grasp force. Tactile array sensing was immune to these problems, and the effect of shear loading was only noticeable for a simple centroid algorithm. The results show that with care, both of these sensing schemes can determine the contact location within a millimeter during real manipulation tasks.
{"title":"Comparison of contact sensor localization abilities during manipulation","authors":"J. Son, M. Cutkosky, R. Howe","doi":"10.1109/IROS.1995.526145","DOIUrl":"https://doi.org/10.1109/IROS.1995.526145","url":null,"abstract":"This paper presents an experimental comparison of tactile array versus force-torque sensing for localizing contact during manipulation. The manipulation tasks involved rotating and translating objects using a planar two fingered manipulator. A pin and a box were selected as limiting cases of point and line contact against a cylindrical robot finger tip. Force-torque contact sensing results suffered from difficulties in calibration, transient forces, and low grasp force. Tactile array sensing was immune to these problems, and the effect of shear loading was only noticeable for a simple centroid algorithm. The results show that with care, both of these sensing schemes can determine the contact location within a millimeter during real manipulation tasks.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115852165","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 : 1995-08-05DOI: 10.1109/IROS.1995.525804
K. Onoguchi, N. Takeda, Mutsumi Watanabe
This paper presents a new road extraction method for an autonomous vehicle which can acquire a road area by using height information of objects. Since a road area can be assumed to be a sequence of a flat plane in front of a vehicle, the road's height information is very effective for extracting a road area. For the purpose, the authors propose a new approach named the planar projection stereopsis (PPS) method which can easily decide whether each point in stereo images exists on the road plane or not. At first, PPS calculates a planar equation representing a road area by using height and pose of a camera in the vehicle. Next, stereo images are projected to the plane, where corresponding points are projected to the same positions on a certain road area if they really exist on a road plane, while corresponding points with different heights from the road plane are projected to different positions in each stereo image. Planar projection description is obtained by a subtraction between projected images from a set of stereo images and a road area can be represented by a set of points with small values. Experimental results for real road scenes have shown the effectiveness of the proposed method.
{"title":"Planar projection stereopsis method for road extraction","authors":"K. Onoguchi, N. Takeda, Mutsumi Watanabe","doi":"10.1109/IROS.1995.525804","DOIUrl":"https://doi.org/10.1109/IROS.1995.525804","url":null,"abstract":"This paper presents a new road extraction method for an autonomous vehicle which can acquire a road area by using height information of objects. Since a road area can be assumed to be a sequence of a flat plane in front of a vehicle, the road's height information is very effective for extracting a road area. For the purpose, the authors propose a new approach named the planar projection stereopsis (PPS) method which can easily decide whether each point in stereo images exists on the road plane or not. At first, PPS calculates a planar equation representing a road area by using height and pose of a camera in the vehicle. Next, stereo images are projected to the plane, where corresponding points are projected to the same positions on a certain road area if they really exist on a road plane, while corresponding points with different heights from the road plane are projected to different positions in each stereo image. Planar projection description is obtained by a subtraction between projected images from a set of stereo images and a road area can be represented by a set of points with small values. Experimental results for real road scenes have shown the effectiveness of the proposed method.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134500149","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 : 1995-08-05DOI: 10.1109/IROS.1995.525803
Mei Chen, T. Jochem, D. Pomerleau
AURORA is a vision-based system designed to warn a vehicle driver of possible impending roadway departure accidents. It employs a downward looking color video camera with a wide angle lens, a digitizer, and a portable Sun Sparc workstation. Using a binormalized adjustable template correlation algorithm, it reliably detects lane markers on structured roads at 60 Hz. A time-to-lane-crossing (TLC) measurement is calculated for each image based on the estimation of vehicle's lateral position and velocity. This measurement is used to trigger an alarm when the TLC falls below a preset threshold. Promising results have been achieved under a variety of weather and lighting conditions, on many road types.
{"title":"AURORA: a vision-based roadway departure warning system","authors":"Mei Chen, T. Jochem, D. Pomerleau","doi":"10.1109/IROS.1995.525803","DOIUrl":"https://doi.org/10.1109/IROS.1995.525803","url":null,"abstract":"AURORA is a vision-based system designed to warn a vehicle driver of possible impending roadway departure accidents. It employs a downward looking color video camera with a wide angle lens, a digitizer, and a portable Sun Sparc workstation. Using a binormalized adjustable template correlation algorithm, it reliably detects lane markers on structured roads at 60 Hz. A time-to-lane-crossing (TLC) measurement is calculated for each image based on the estimation of vehicle's lateral position and velocity. This measurement is used to trigger an alarm when the TLC falls below a preset threshold. Promising results have been achieved under a variety of weather and lighting conditions, on many road types.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134534230","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 : 1995-08-05DOI: 10.1109/IROS.1995.526159
D. Chang, M. Cutkosky
The superiority of deformable human fingertips as compared to hard robot gripper fingers for grasping and manipulation has lead to a number of investigations with robot hands employing elastomers or materials such as fluids or powders beneath a membrane at the fingertips. When using such materials, it is important to account for their properties during manipulation. The rigid-body rolling kinematic equations developed and applied in previous investigations do not consider load- and object-dependent fingertip deformations. This paper is concerned with determining the kinematic effects of soft fingertips during manipulation with rolling. The long-term goal of this work is to produce a model of rolling with soft fingertips that can be incorporated into a real-time control system to produce current best estimates of contact locations and velocities when planning and executing rolling maneuvers.
{"title":"Rolling with deformable fingertips","authors":"D. Chang, M. Cutkosky","doi":"10.1109/IROS.1995.526159","DOIUrl":"https://doi.org/10.1109/IROS.1995.526159","url":null,"abstract":"The superiority of deformable human fingertips as compared to hard robot gripper fingers for grasping and manipulation has lead to a number of investigations with robot hands employing elastomers or materials such as fluids or powders beneath a membrane at the fingertips. When using such materials, it is important to account for their properties during manipulation. The rigid-body rolling kinematic equations developed and applied in previous investigations do not consider load- and object-dependent fingertip deformations. This paper is concerned with determining the kinematic effects of soft fingertips during manipulation with rolling. The long-term goal of this work is to produce a model of rolling with soft fingertips that can be incorporated into a real-time control system to produce current best estimates of contact locations and velocities when planning and executing rolling maneuvers.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"300 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134371661","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 : 1995-08-05DOI: 10.1109/IROS.1995.526150
N. Kawarazaki, K. Taguchi
This paper provides a new method for obtaining a collision free path for a manipulator. The proposal in this paper consists of two steps. First, a free form surface is defined that covers collision regions and includes start and goal points in the configuration space, called the path restricted curved surface (PRCS). The PRCS is described by Bezier's surface and it is a collision-free area. The second step is to generate the optimized path on the PRCS. The path on the PRCS is selected to connect the geodesic from start to goal points. The geodesic in the configuration space is the most suitable path in the point to minimize the total value of manipulator's joint angle changes. The effectiveness of this method is clarified by computer simulation with 30 graphics. This method can be said to apply differential geometry to the configuration space method.
{"title":"Collision-free path planning for a manipulator using free form surface","authors":"N. Kawarazaki, K. Taguchi","doi":"10.1109/IROS.1995.526150","DOIUrl":"https://doi.org/10.1109/IROS.1995.526150","url":null,"abstract":"This paper provides a new method for obtaining a collision free path for a manipulator. The proposal in this paper consists of two steps. First, a free form surface is defined that covers collision regions and includes start and goal points in the configuration space, called the path restricted curved surface (PRCS). The PRCS is described by Bezier's surface and it is a collision-free area. The second step is to generate the optimized path on the PRCS. The path on the PRCS is selected to connect the geodesic from start to goal points. The geodesic in the configuration space is the most suitable path in the point to minimize the total value of manipulator's joint angle changes. The effectiveness of this method is clarified by computer simulation with 30 graphics. This method can be said to apply differential geometry to the configuration space method.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130832295","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 : 1995-08-05DOI: 10.1109/IROS.1995.525923
M. Wada, Yasutaka Tominaga, S. Mori
An omnidirectional holonomic mobile robot assembled with nonholonomic wheels has been proposed. The driving wheel axis of the nonholonomic wheel has an offset distance from the steering axis of the wheel. A wheel of this style is representative of the nonholonomic system and is conventionally used for a caster wheel. In the case of the proposed mobile robot, a wheel of this style is used as a driven wheel by actuating a wheel axle and a steering axle independently. First, we describe the modeling and control of the single nonholonomic wheel, and then describe the holonomic vehicle which has a couple of these nonholonomic wheels. To avoid the nonholonomic characteristics of the wheel, we have introduced a control method which restricts the controlled statement to only the translational velocity of the supporting point of the wheel. Computer simulations of the single wheel and of the two wheeled vehicle, and experimental results of the single wheel have shown good performances.
{"title":"Omnidirectional holonomic mobile robot using nonholonomic wheels","authors":"M. Wada, Yasutaka Tominaga, S. Mori","doi":"10.1109/IROS.1995.525923","DOIUrl":"https://doi.org/10.1109/IROS.1995.525923","url":null,"abstract":"An omnidirectional holonomic mobile robot assembled with nonholonomic wheels has been proposed. The driving wheel axis of the nonholonomic wheel has an offset distance from the steering axis of the wheel. A wheel of this style is representative of the nonholonomic system and is conventionally used for a caster wheel. In the case of the proposed mobile robot, a wheel of this style is used as a driven wheel by actuating a wheel axle and a steering axle independently. First, we describe the modeling and control of the single nonholonomic wheel, and then describe the holonomic vehicle which has a couple of these nonholonomic wheels. To avoid the nonholonomic characteristics of the wheel, we have introduced a control method which restricts the controlled statement to only the translational velocity of the supporting point of the wheel. Computer simulations of the single wheel and of the two wheeled vehicle, and experimental results of the single wheel have shown good performances.","PeriodicalId":124483,"journal":{"name":"Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131023523","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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