Pub Date : 2012-03-25DOI: 10.1109/AMC.2012.6197025
Yoshiyuki Hatta, T. Shimono, N. Motoi
In recent years, haptic communication with teleoperation systems has been actively researched. One of the effective methods for haptic communication is bilateral motion control based on acceleration control. If the acceleration-based bilateral control is applied to a parallel multi-degrees-of-freedom (MDOF) system, complicated haptic human motion can be realized in the remote site. However it is difficult to understand whole motion of the system based only on information of each actuator. One of the effective methods for the motion recognition is modal decomposition based on Discrete Fourier series expansion (DFS). This modal decomposition is effective for the analysis of motion of parallel MDOF systems. However, in order to apply the modal decomposition, it is necessary that an arrangement of the parallel MDOF system is known. This paper proposes an arrangement identification method for parallel MDOF teleoperation systems based on Levenberg-Marquardt (LM) method. The method can estimate the arrangement, even if there is no visual information. Finally, the validity of the proposed method is confirmed by the experimental results.
{"title":"An arrangement identification method for parallel multi-degrees-of-freedom teleoperation systems based on Levenberg-Marquardt method","authors":"Yoshiyuki Hatta, T. Shimono, N. Motoi","doi":"10.1109/AMC.2012.6197025","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197025","url":null,"abstract":"In recent years, haptic communication with teleoperation systems has been actively researched. One of the effective methods for haptic communication is bilateral motion control based on acceleration control. If the acceleration-based bilateral control is applied to a parallel multi-degrees-of-freedom (MDOF) system, complicated haptic human motion can be realized in the remote site. However it is difficult to understand whole motion of the system based only on information of each actuator. One of the effective methods for the motion recognition is modal decomposition based on Discrete Fourier series expansion (DFS). This modal decomposition is effective for the analysis of motion of parallel MDOF systems. However, in order to apply the modal decomposition, it is necessary that an arrangement of the parallel MDOF system is known. This paper proposes an arrangement identification method for parallel MDOF teleoperation systems based on Levenberg-Marquardt (LM) method. The method can estimate the arrangement, even if there is no visual information. Finally, the validity of the proposed method is confirmed by the experimental results.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"1993 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82390294","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197028
M. Mizuochi, K. Ohnishi
Precise bilateral teleoperation based on wide-band signals enables an operator to achieve complicated tasks. A short sampling period is required for acquisition and transmission of wide-band signals. The sampling period is limited, however, when controllers are connected through a network. In this paper, a coding and decoding scheme for wide-band bilateral teleoperation is proposed. The method uses a low pass filter and discrete Fourier transform for the coding and inverse discrete Fourier transform for the decoding. High frequency signals can be transmitted even under severe limitation on the packet transmission rate. The scheme was verified through experiment with bilateral teleoperation. The validity of the proposed method was confirmed in terms of the transmission of wide-band signals and the reproduction of wide-band haptic sensation.
{"title":"Coding and decoding scheme for wide-band bilateral teleoperation","authors":"M. Mizuochi, K. Ohnishi","doi":"10.1109/AMC.2012.6197028","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197028","url":null,"abstract":"Precise bilateral teleoperation based on wide-band signals enables an operator to achieve complicated tasks. A short sampling period is required for acquisition and transmission of wide-band signals. The sampling period is limited, however, when controllers are connected through a network. In this paper, a coding and decoding scheme for wide-band bilateral teleoperation is proposed. The method uses a low pass filter and discrete Fourier transform for the coding and inverse discrete Fourier transform for the decoding. High frequency signals can be transmitted even under severe limitation on the packet transmission rate. The scheme was verified through experiment with bilateral teleoperation. The validity of the proposed method was confirmed in terms of the transmission of wide-band signals and the reproduction of wide-band haptic sensation.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"51 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82777306","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197027
E. D. Kunt, A. T. Naskali, A. Sabanoviç
In this paper, design and control issues for the development of miniaturized manipulators which are aimed to be used in high precision assembly and manipulation tasks are presented. The developed manipulators are size adapted devices, miniaturized versions of conventional robots based on well-known kinematic structures. 3 degrees of freedom (DOF) delta robot and a 2 DOF pantograph mechanism enhanced with a rotational axis at the tip and a Z axis actuating the whole mechanism are given as examples of study. These parallel mechanisms are designed and developed to be used in modular assembly systems for the realization of high precision assembly and manipulation tasks. In that sense, modularity is addressed as an important design consideration. The design procedures are given in details in order to provide solutions for miniaturization and experimental results are given to show the achieved performances.
{"title":"Miniaturized modular manipulator design for high precision assembly and manipulation tasks","authors":"E. D. Kunt, A. T. Naskali, A. Sabanoviç","doi":"10.1109/AMC.2012.6197027","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197027","url":null,"abstract":"In this paper, design and control issues for the development of miniaturized manipulators which are aimed to be used in high precision assembly and manipulation tasks are presented. The developed manipulators are size adapted devices, miniaturized versions of conventional robots based on well-known kinematic structures. 3 degrees of freedom (DOF) delta robot and a 2 DOF pantograph mechanism enhanced with a rotational axis at the tip and a Z axis actuating the whole mechanism are given as examples of study. These parallel mechanisms are designed and developed to be used in modular assembly systems for the realization of high precision assembly and manipulation tasks. In that sense, modularity is addressed as an important design consideration. The design procedures are given in details in order to provide solutions for miniaturization and experimental results are given to show the achieved performances.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"42 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88007657","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197138
Elmir Babovic
This research is extension of previous research on method of Collaborative and Non-Collaborative Dynamic Path Prediction Algorithm for Mobile Agents Collision Detection with Dynamic Obstacles in 3D Space. In this research the extension of the algorithm for dynamic collaborative path prediction for mobile agents is proposed and two important issues Coefficient of agility and Minimal sampling frequency are analyzed. Those two terms are proposed in previous research for which background and introduction is explained in this paper. Solving Coefficient of agility and minimal sampling frequency issues allows system designers and developers to implement the method. This method allows full decentralization of collision detection which allows many advantages from minimizing of network traffic to simplifying of inclusion of additional agents in relevant space. Implementation of the algorithm will be low resource consuming allowing mobile agents to free resources for additional tasks.
{"title":"Coefficient of agility and sampling frequency issues in Mobile Agents Collision Detection with Dynamic Obstacles in 3D Space","authors":"Elmir Babovic","doi":"10.1109/AMC.2012.6197138","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197138","url":null,"abstract":"This research is extension of previous research on method of Collaborative and Non-Collaborative Dynamic Path Prediction Algorithm for Mobile Agents Collision Detection with Dynamic Obstacles in 3D Space. In this research the extension of the algorithm for dynamic collaborative path prediction for mobile agents is proposed and two important issues Coefficient of agility and Minimal sampling frequency are analyzed. Those two terms are proposed in previous research for which background and introduction is explained in this paper. Solving Coefficient of agility and minimal sampling frequency issues allows system designers and developers to implement the method. This method allows full decentralization of collision detection which allows many advantages from minimizing of network traffic to simplifying of inclusion of additional agents in relevant space. Implementation of the algorithm will be low resource consuming allowing mobile agents to free resources for additional tasks.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"69 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85855478","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197042
M. Boegli, T. Laet, J. Schutter, J. Swevers
This paper presents a smoothed friction model that closely approximates the Generalized Maxwell-Slip (GMS) model, a multi-state friction model known to describe all essential friction characteristics in presliding and sliding motion. In contrast to the GMS model, which consists of a switching structure to accommodate for its hybrid nature, the Smoothed GMS (S-GMS) model consists of an analytic set of differential equations well suited for on-line state and parameter estimation, such as in Moving Horizon Estimation (MHE). Efficient on-line state and parameter estimation is essential for model-based friction compensation in order to track friction characteristics changes in time and space. Moreover, MHE is known to better handle model nonlinearities, disturbances and constraints than Extended Kalman Filter (EKF). This paper discusses the implementation of the EKF and MHE estimators for both the GMS and the S-GMS friction models. The benefit of the combination of MHE and S-GMS model is shown.
{"title":"A Smoothed GMS friction model for Moving Horizon friction state and parameter estimation","authors":"M. Boegli, T. Laet, J. Schutter, J. Swevers","doi":"10.1109/AMC.2012.6197042","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197042","url":null,"abstract":"This paper presents a smoothed friction model that closely approximates the Generalized Maxwell-Slip (GMS) model, a multi-state friction model known to describe all essential friction characteristics in presliding and sliding motion. In contrast to the GMS model, which consists of a switching structure to accommodate for its hybrid nature, the Smoothed GMS (S-GMS) model consists of an analytic set of differential equations well suited for on-line state and parameter estimation, such as in Moving Horizon Estimation (MHE). Efficient on-line state and parameter estimation is essential for model-based friction compensation in order to track friction characteristics changes in time and space. Moreover, MHE is known to better handle model nonlinearities, disturbances and constraints than Extended Kalman Filter (EKF). This paper discusses the implementation of the EKF and MHE estimators for both the GMS and the S-GMS friction models. The benefit of the combination of MHE and S-GMS model is shown.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"22 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89110142","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197149
M. Huba
The paper represents first part of two contributions dealing with simplified modular design of constrained P and disturbance observer (DO) based PI control with different filtering properties illustrated by example of speed servo control. This first part is devoted to analysis of the core structure of the P controller tuned for different types of nonmodelled or filter dynamics. Openness of the approach means that for approximating additional dynamics of the P-controller structure different filters may be used without necessity to repeat in the nominal case analysis of the optimal and critical tuning. By simpler means, flexible approach enabling to fit requirements of particular loop and simultaneously offering reasonably better performance than the traditional controller design based on Luenberger disturbance observer for reconstruction of the velocity signal is proposed. Achieved performance is evaluated by newly introduced measures for deviations from monotonic and one-pulse shapes of transients typical for control of plants with dominant 1st order dynamics.
{"title":"Open flexible P-controller design","authors":"M. Huba","doi":"10.1109/AMC.2012.6197149","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197149","url":null,"abstract":"The paper represents first part of two contributions dealing with simplified modular design of constrained P and disturbance observer (DO) based PI control with different filtering properties illustrated by example of speed servo control. This first part is devoted to analysis of the core structure of the P controller tuned for different types of nonmodelled or filter dynamics. Openness of the approach means that for approximating additional dynamics of the P-controller structure different filters may be used without necessity to repeat in the nominal case analysis of the optimal and critical tuning. By simpler means, flexible approach enabling to fit requirements of particular loop and simultaneously offering reasonably better performance than the traditional controller design based on Luenberger disturbance observer for reconstruction of the velocity signal is proposed. Achieved performance is evaluated by newly introduced measures for deviations from monotonic and one-pulse shapes of transients typical for control of plants with dominant 1st order dynamics.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"131 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86188481","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197040
Y. Seki, H. Fujimoto, K. Saiki
In general, Gantry-type precision stages have low resonance modes because the structure of the stages are large and complex. These resonance modes cause a pitch motion during the translation driving. In this paper, an optimal mechanical parameter design method is analyzed and explored via a two-inertia model. In these modes, primary resonance can be suppressed by Self Resonance Cancellation (SRC) and secondary resonance can be reduced by adjusting the mechanical parameters of the stage. Simulations and experiments with an experimental precision stage are performed to show the advantages of the proposed optimization design method.
{"title":"Optimal mechanical parameter design using Self Resonance Cancellation control for gantry-type high precision stage","authors":"Y. Seki, H. Fujimoto, K. Saiki","doi":"10.1109/AMC.2012.6197040","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197040","url":null,"abstract":"In general, Gantry-type precision stages have low resonance modes because the structure of the stages are large and complex. These resonance modes cause a pitch motion during the translation driving. In this paper, an optimal mechanical parameter design method is analyzed and explored via a two-inertia model. In these modes, primary resonance can be suppressed by Self Resonance Cancellation (SRC) and secondary resonance can be reduced by adjusting the mechanical parameters of the stage. Simulations and experiments with an experimental precision stage are performed to show the advantages of the proposed optimization design method.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"10 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86063017","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197100
T. Ishii, S. Katsura
Bilateral teleoperation system through network is negatively affected to stability by communication delay. In this paper, bilateral teleoperation system is researched toward a delay free bilateral teleoperation. By using 2ch bilateral control which is transmitting and controlling only positions, the stability of bilateral teleoperation system is enhanced. However, the bilateral teleoperation controlling only position increases force needed to operate master system. So, the operationality comes down, and teleoperation becomes difficult. Therefore, in order to enhance the operationality, local force feedback loop is added, and external force is controlled to 0. So, the proposed method enhances the stability while keeping good operationality. As a result, it turns out that the bilateral control system can enhance the performance of communication delay by reducing connectability of master and slave.
{"title":"Bilateral control with local force feedback for delay-free teleoperation","authors":"T. Ishii, S. Katsura","doi":"10.1109/AMC.2012.6197100","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197100","url":null,"abstract":"Bilateral teleoperation system through network is negatively affected to stability by communication delay. In this paper, bilateral teleoperation system is researched toward a delay free bilateral teleoperation. By using 2ch bilateral control which is transmitting and controlling only positions, the stability of bilateral teleoperation system is enhanced. However, the bilateral teleoperation controlling only position increases force needed to operate master system. So, the operationality comes down, and teleoperation becomes difficult. Therefore, in order to enhance the operationality, local force feedback loop is added, and external force is controlled to 0. So, the proposed method enhances the stability while keeping good operationality. As a result, it turns out that the bilateral control system can enhance the performance of communication delay by reducing connectability of master and slave.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"5 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89693407","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197054
Y. Kimura, Sehoon Oh, Y. Hori
This paper proposes kinematics and a control algorithm to control a two-link manipulator to simulate a spring loaded inverted pendulum (SLIP). End-effector kinematics is derived in the reference frame that is defined along the axis that connects the first joint and the end-effector. The derivation of this kinematics reveals that a biarticular actuator is suitable for this kinematics. Based on this kinematics, a disturbance observer is designed in the same reference frame. This disturbance observer removes the unnecessary inertia coupling without calculation of Jacobian matrix.
{"title":"Leg space observer on biarticular actuated two-link manipulator for realizing spring loaded inverted pendulum model","authors":"Y. Kimura, Sehoon Oh, Y. Hori","doi":"10.1109/AMC.2012.6197054","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197054","url":null,"abstract":"This paper proposes kinematics and a control algorithm to control a two-link manipulator to simulate a spring loaded inverted pendulum (SLIP). End-effector kinematics is derived in the reference frame that is defined along the axis that connects the first joint and the end-effector. The derivation of this kinematics reveals that a biarticular actuator is suitable for this kinematics. Based on this kinematics, a disturbance observer is designed in the same reference frame. This disturbance observer removes the unnecessary inertia coupling without calculation of Jacobian matrix.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"16 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86674732","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 : 2012-03-25DOI: 10.1109/AMC.2012.6197031
Mireia Perez Plius, Metin Yílmaz, Utku Seven, K. Erbatur
Force control of robotic manipulators is becoming more and more important in applications that involve interaction with the environment. Depending on the nature of the task at hand, different control algorithms can be suitable to be implemented. In this paper the task of reaching an object by the robot tool and applying a constant force on it is considered as a case study. This task is one of the typical manipulation operations. A fuzzy logic scheduling approach, which smoothly changes the control action between two force control schemes, is proposed. The first force control method is admittance control, which is suitable to be used in the phase of approaching the work piece. The second one is an explicit force control strategy, integral force control, suitable for force regulation when the manipulator tool is in contact with the work piece. The fuzzy controller scheduling approach is tested via experimental work on a direct drive SCARA-type manipulator. It is also compared with a crisp controller switching method. Experiments are carried out with fixed and free-to-move work pieces. The results validate that the proposed fuzzy transition has advantages over a crisp switching between controllers.
{"title":"Fuzzy controller scheduling for robotic manipulator force control","authors":"Mireia Perez Plius, Metin Yílmaz, Utku Seven, K. Erbatur","doi":"10.1109/AMC.2012.6197031","DOIUrl":"https://doi.org/10.1109/AMC.2012.6197031","url":null,"abstract":"Force control of robotic manipulators is becoming more and more important in applications that involve interaction with the environment. Depending on the nature of the task at hand, different control algorithms can be suitable to be implemented. In this paper the task of reaching an object by the robot tool and applying a constant force on it is considered as a case study. This task is one of the typical manipulation operations. A fuzzy logic scheduling approach, which smoothly changes the control action between two force control schemes, is proposed. The first force control method is admittance control, which is suitable to be used in the phase of approaching the work piece. The second one is an explicit force control strategy, integral force control, suitable for force regulation when the manipulator tool is in contact with the work piece. The fuzzy controller scheduling approach is tested via experimental work on a direct drive SCARA-type manipulator. It is also compared with a crisp controller switching method. Experiments are carried out with fixed and free-to-move work pieces. The results validate that the proposed fuzzy transition has advantages over a crisp switching between controllers.","PeriodicalId":6439,"journal":{"name":"2012 12th IEEE International Workshop on Advanced Motion Control (AMC)","volume":"1 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82230153","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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