Pub Date : 2009-07-08DOI: 10.1109/CCA.2009.5281082
H. Priyadarshan, H. Pillai
Unlike linear dynamical systems the existence and uniqueness of solutions (wellposedness) for linear complementarity systems (LCS) is not trivial. It has been shown in literature that the consistent and jump space of an LCS (with zero input) plays an important role in establishing the wellposedness. In this paper we apply state and port feedback to an LCS to reorient these spaces. Sometimes it is desirable to increase the consistent space which means enlarging the set of states having continuous extension. At the same time it may be desirable to shrink the set of states which may have discontinuous extension, in other words, to decrease the jump space. Sufficient conditions in this direction are obtained in terms of feedback matrices.
{"title":"Reorienting linear complementarity systems using feedback","authors":"H. Priyadarshan, H. Pillai","doi":"10.1109/CCA.2009.5281082","DOIUrl":"https://doi.org/10.1109/CCA.2009.5281082","url":null,"abstract":"Unlike linear dynamical systems the existence and uniqueness of solutions (wellposedness) for linear complementarity systems (LCS) is not trivial. It has been shown in literature that the consistent and jump space of an LCS (with zero input) plays an important role in establishing the wellposedness. In this paper we apply state and port feedback to an LCS to reorient these spaces. Sometimes it is desirable to increase the consistent space which means enlarging the set of states having continuous extension. At the same time it may be desirable to shrink the set of states which may have discontinuous extension, in other words, to decrease the jump space. Sufficient conditions in this direction are obtained in terms of feedback matrices.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127651891","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 : 2009-07-08DOI: 10.1109/CCA.2009.5281072
Md. Jahangir Hossain, H. Pota, V. Ugrinovskii, R. Ramos
In this paper, a novel robust controller for a Static Synchronous Compensator (STATCOM) is presented to enhance the fault ride-through (FRT) capability of fixed speed induction generators (FSIGs), the most common type of generators that can be found in wind farms. The effects of STATCOM rating and wind farm integration on FRT capability of FSIGs are studied analytically using the power-voltage and torque-slip relationships as well as through simulations. The wind generator is a highly nonlinear system, which is modelled in this work as a linear part plus a nonlinear part, the nonlinear term being the Cauchy remainder term in the Taylor series expansion and of the equations used to model the wind farm. Bounds derived for this Cauchy remainder term are used to define an uncertain linear model for which a robust control design is performed. The controller resulting from this robust design provides an acceptable performance over a wide range of conditions needed to operate the wind farm during severe faults. The performance of the designed controller is demonstrated by large disturbance simulations on a test system.
{"title":"Robust STATCOM control for the enhancement of fault ride-through capability of fixed speed wind generators","authors":"Md. Jahangir Hossain, H. Pota, V. Ugrinovskii, R. Ramos","doi":"10.1109/CCA.2009.5281072","DOIUrl":"https://doi.org/10.1109/CCA.2009.5281072","url":null,"abstract":"In this paper, a novel robust controller for a Static Synchronous Compensator (STATCOM) is presented to enhance the fault ride-through (FRT) capability of fixed speed induction generators (FSIGs), the most common type of generators that can be found in wind farms. The effects of STATCOM rating and wind farm integration on FRT capability of FSIGs are studied analytically using the power-voltage and torque-slip relationships as well as through simulations. The wind generator is a highly nonlinear system, which is modelled in this work as a linear part plus a nonlinear part, the nonlinear term being the Cauchy remainder term in the Taylor series expansion and of the equations used to model the wind farm. Bounds derived for this Cauchy remainder term are used to define an uncertain linear model for which a robust control design is performed. The controller resulting from this robust design provides an acceptable performance over a wide range of conditions needed to operate the wind farm during severe faults. The performance of the designed controller is demonstrated by large disturbance simulations on a test system.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128148302","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 : 2009-07-08DOI: 10.1109/CCA.2009.5281126
Wen-June Wang, Cheng-Hao Huang
This paper presents a fuzzy parallel distributed compensation (PDC) control design for balancing a two-wheeled inverted pendulum (TWIP). A Takagi-Sugeno (T-S) fuzzy model can be firstly constructed from the nonlinear system model of the TWIP. Based on the T-S fuzzy model, a PDC controller is designed with the aid of linear matrix inequality (LMI) concept. The stability of the fuzzy balance control can be guaranteed by solving the inequalities of LMI. Finally, one simulation and its equivalent experiment are given to demonstrate the effectiveness and feasibility of the control scheme.
{"title":"Model-based fuzzy control application to a self-balancing two-wheeled inverted pendulum","authors":"Wen-June Wang, Cheng-Hao Huang","doi":"10.1109/CCA.2009.5281126","DOIUrl":"https://doi.org/10.1109/CCA.2009.5281126","url":null,"abstract":"This paper presents a fuzzy parallel distributed compensation (PDC) control design for balancing a two-wheeled inverted pendulum (TWIP). A Takagi-Sugeno (T-S) fuzzy model can be firstly constructed from the nonlinear system model of the TWIP. Based on the T-S fuzzy model, a PDC controller is designed with the aid of linear matrix inequality (LMI) concept. The stability of the fuzzy balance control can be guaranteed by solving the inequalities of LMI. Finally, one simulation and its equivalent experiment are given to demonstrate the effectiveness and feasibility of the control scheme.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"372 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133346963","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 : 2009-07-08DOI: 10.1109/CCA.2009.5280709
R. Colbaugh, K. Glass
This two-part paper presents a new approach to predictive analysis for social processes. In Part I, we begin by identifying a class of social processes which are simultaneously important in applications and difficult to predict using existing methods. It is shown that these processes can be modeled within a multi-scale, stochastic hybrid system framework that is sociologically sensible, expressive, illuminating, and amenable to formal analysis. Among other advantages, the proposed modeling framework enables proper characterization of the interplay between the intrinsic aspects of a social process (e.g., the “appeal” of a political movement) and the social dynamics which are its realization; this characterization is key to successful social process prediction. The utility of the modeling methodology is illustrated through a case study involving the global SARS epidemic of 2002–2003. Part II of the paper then leverages this modeling framework to develop a rigorous, computationally tractable approach to social process predictive analysis.
{"title":"Predictive analysis for social processes I: Multi-scale hybrid system modeling","authors":"R. Colbaugh, K. Glass","doi":"10.1109/CCA.2009.5280709","DOIUrl":"https://doi.org/10.1109/CCA.2009.5280709","url":null,"abstract":"This two-part paper presents a new approach to predictive analysis for social processes. In Part I, we begin by identifying a class of social processes which are simultaneously important in applications and difficult to predict using existing methods. It is shown that these processes can be modeled within a multi-scale, stochastic hybrid system framework that is sociologically sensible, expressive, illuminating, and amenable to formal analysis. Among other advantages, the proposed modeling framework enables proper characterization of the interplay between the intrinsic aspects of a social process (e.g., the “appeal” of a political movement) and the social dynamics which are its realization; this characterization is key to successful social process prediction. The utility of the modeling methodology is illustrated through a case study involving the global SARS epidemic of 2002–2003. Part II of the paper then leverages this modeling framework to develop a rigorous, computationally tractable approach to social process predictive analysis.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134030723","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 : 2009-07-08DOI: 10.1109/CCA.2009.5280998
R. García-Hernández, E. Sánchez, V. Santibáñez, M. Llama, E. Bayro-Corrochano
This paper deals with adaptive trajectory tracking for discrete-time MIMO nonlinear systems. A high order neural network (HONN) is used to approximate a decentralized control law designed by the backstepping technique as applied to a block strict feedback form (BSFF). The HONN learning is performed online by an Extended Kalman Filter (EKF) algorithm. The proposed scheme is implemented in real-time to control a two DOF robot manipulator.
{"title":"Real-time decentralized neural backstepping controller for a robot manipulator","authors":"R. García-Hernández, E. Sánchez, V. Santibáñez, M. Llama, E. Bayro-Corrochano","doi":"10.1109/CCA.2009.5280998","DOIUrl":"https://doi.org/10.1109/CCA.2009.5280998","url":null,"abstract":"This paper deals with adaptive trajectory tracking for discrete-time MIMO nonlinear systems. A high order neural network (HONN) is used to approximate a decentralized control law designed by the backstepping technique as applied to a block strict feedback form (BSFF). The HONN learning is performed online by an Extended Kalman Filter (EKF) algorithm. The proposed scheme is implemented in real-time to control a two DOF robot manipulator.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132290450","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 : 2009-07-08DOI: 10.1109/CCA.2009.5281183
E. Olofsson, P1er Brunsell, J. Drake
The reversed-field pinch (RFP) EXTRAP-T2R (T2R) is a plasma physics experiment with particular relevance for magnetic confinement fusion (MCF) research. T2R is very well equipped for investigations of magnetohydrodynamic (MHD) instabilities known as resistive-wall modes (RWMs), growing on a time-scale set by a surrounding non-perfectly conducting shell. The RWM instability is also subject of intense research in tokamak experiments (another MCF configuration). Recently, multiple RWMs have been stabilized in T2R using arrays of active (current-carrying) and sensor (voltage-measuring) coils equidistributed on the shell. In this paper, the MHD normal modes dynamics is probed in the required feedback operation by simultaneously, and pseudo-randomly, exciting the spectrum in the spatial sense. Spectra are then extracted by predictionerror minimization based on an observer that tracks dynamically aliased modes and the results thus obtained are related, and compared, to established linear MHD stability theory. This pioneer study at T2R is, arguably, appealling both to plasma physicists and automatic control staff.
{"title":"Closed-loop direct parametric identification of magnetohydrodynamic normal modes spectra in EXTRAP-T2R reversed-field pinch","authors":"E. Olofsson, P1er Brunsell, J. Drake","doi":"10.1109/CCA.2009.5281183","DOIUrl":"https://doi.org/10.1109/CCA.2009.5281183","url":null,"abstract":"The reversed-field pinch (RFP) EXTRAP-T2R (T2R) is a plasma physics experiment with particular relevance for magnetic confinement fusion (MCF) research. T2R is very well equipped for investigations of magnetohydrodynamic (MHD) instabilities known as resistive-wall modes (RWMs), growing on a time-scale set by a surrounding non-perfectly conducting shell. The RWM instability is also subject of intense research in tokamak experiments (another MCF configuration). Recently, multiple RWMs have been stabilized in T2R using arrays of active (current-carrying) and sensor (voltage-measuring) coils equidistributed on the shell. In this paper, the MHD normal modes dynamics is probed in the required feedback operation by simultaneously, and pseudo-randomly, exciting the spectrum in the spatial sense. Spectra are then extracted by predictionerror minimization based on an observer that tracks dynamically aliased modes and the results thus obtained are related, and compared, to established linear MHD stability theory. This pioneer study at T2R is, arguably, appealling both to plasma physicists and automatic control staff.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114385147","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 : 2009-07-08DOI: 10.1109/CCA.2009.5281137
A. Aleksandrov, Yangzhou Chen, A. Platonov, Liguo Zhang
The problems of stability analysis and synthesis for a class of nonlinear switched systems are addressed in the paper. For arbitrary switching laws and any admissible nonlinear dynamical equations, sufficient linear inequalities conditions are investigated to make such systems are absolutely stable. Next, based on the constructive approach of the common Lyapunov function, a uniform ultimate boundedness controller is developed to guarantee the practical stability of the switched systems with the nonlinear and time-varying uncertain disturbance. A numerical example is given to demonstrate the efficiency of the proposed approach.
{"title":"Stability analysis and design of uniform ultimate boundedness control for a class of nonlinear switched systems","authors":"A. Aleksandrov, Yangzhou Chen, A. Platonov, Liguo Zhang","doi":"10.1109/CCA.2009.5281137","DOIUrl":"https://doi.org/10.1109/CCA.2009.5281137","url":null,"abstract":"The problems of stability analysis and synthesis for a class of nonlinear switched systems are addressed in the paper. For arbitrary switching laws and any admissible nonlinear dynamical equations, sufficient linear inequalities conditions are investigated to make such systems are absolutely stable. Next, based on the constructive approach of the common Lyapunov function, a uniform ultimate boundedness controller is developed to guarantee the practical stability of the switched systems with the nonlinear and time-varying uncertain disturbance. A numerical example is given to demonstrate the efficiency of the proposed approach.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124800585","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 : 2009-07-08DOI: 10.1109/CCA.2009.5280927
R. Amari, P. Tona, M. Alamir
In this paper, a phenomenological model of clutch torque transmissibility is proposed. This model applies to clutch engagement during vehicle start-up in both manual and automated-manual configurations. The proposed model can be identified through on board measurements available in most production vehicles. The model is based on the identification of a nonlinear characteristic that relates the transmissibility of engine torque to the mainshaft to the clutch actuator position and the clutch slip speed. To smooth the effect of neglected dependencies on torque transmissibility and obtain a non-linear characteristic with very low dispersion, the engine torque setpoint is also included in the model. An empirical estimation of load torque during start-up, dependent on slip speed and engine torque set-point, completes the model and improves its accuracy. The model has been identified and validated on two prototype vehicles with very different features: a small city car with an electrically-actuated automated manual transmission and a big executive car with a hydraulic-actuated manual transmission. An application example is given at the end of the paper to show the usefulness of the model: an alternative analysis, based on power computation, of the conditions that have to be respected to avoid oscillations at clutch engagement.
{"title":"A phenomenological model for torque transmissibility during dry clutch engagement","authors":"R. Amari, P. Tona, M. Alamir","doi":"10.1109/CCA.2009.5280927","DOIUrl":"https://doi.org/10.1109/CCA.2009.5280927","url":null,"abstract":"In this paper, a phenomenological model of clutch torque transmissibility is proposed. This model applies to clutch engagement during vehicle start-up in both manual and automated-manual configurations. The proposed model can be identified through on board measurements available in most production vehicles. The model is based on the identification of a nonlinear characteristic that relates the transmissibility of engine torque to the mainshaft to the clutch actuator position and the clutch slip speed. To smooth the effect of neglected dependencies on torque transmissibility and obtain a non-linear characteristic with very low dispersion, the engine torque setpoint is also included in the model. An empirical estimation of load torque during start-up, dependent on slip speed and engine torque set-point, completes the model and improves its accuracy. The model has been identified and validated on two prototype vehicles with very different features: a small city car with an electrically-actuated automated manual transmission and a big executive car with a hydraulic-actuated manual transmission. An application example is given at the end of the paper to show the usefulness of the model: an alternative analysis, based on power computation, of the conditions that have to be respected to avoid oscillations at clutch engagement.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125139268","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 : 2009-07-08DOI: 10.1109/CCA.2009.5281016
S. Salehizadeh, P. Yadmellat, M. Menhaj
This paper proposes a novel optimization method in order to real time implementation based on standard particle swarm optimization idea and characteristics of chaotic maps which is named as individual particle optimization (IPO). Three typical benchmark functions are used to validate the proposed algorithm performance and runtime and then compare with that of the other algorithms known as modified PSOs. Six functions reported in SIS2005 are used to better verification of the proposed algorithm. Numerical results indicate that IPO is competitive due to its more competitive convergence rate and ability to find the functions' global optimum.
{"title":"Transition from particle swarm optimization to individual particle optimization","authors":"S. Salehizadeh, P. Yadmellat, M. Menhaj","doi":"10.1109/CCA.2009.5281016","DOIUrl":"https://doi.org/10.1109/CCA.2009.5281016","url":null,"abstract":"This paper proposes a novel optimization method in order to real time implementation based on standard particle swarm optimization idea and characteristics of chaotic maps which is named as individual particle optimization (IPO). Three typical benchmark functions are used to validate the proposed algorithm performance and runtime and then compare with that of the other algorithms known as modified PSOs. Six functions reported in SIS2005 are used to better verification of the proposed algorithm. Numerical results indicate that IPO is competitive due to its more competitive convergence rate and ability to find the functions' global optimum.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"191 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134238500","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 : 2009-07-08DOI: 10.1109/CCA.2009.5281021
S. V. D. Meulen, B. D. Jager, E. Noll, F. Veldpaus, F. Sluis, M. Steinbuch
The control design for the variator in a pushbelt continuously variable transmission (CVT) is investigated. The variator enables a stepless variation of the transmission ratio within a finite range. A conventional control design for the variator is typically obtained by the use of a variator model, which incorporates large uncertainties and, therefore, limits the variator efficiency. In this paper, a control design for the variator is discussed, which improves the variator efficiency and limits the number of sensors. The relation between inputs and outputs of the variator is investigated, from which one input-output map is identified, which exhibits a maximum. This maximum indicates performance in terms of the variator efficiency. For this reason, this input-output map is maximized by means of extremum seeking control (ESC), which omits the use of a variator model. Experiments illustrate that the approach is feasible and show that a conventional control design for the variator is outperformed.
{"title":"Improving pushbelt continuously variable transmission efficiency via extremum seeking control","authors":"S. V. D. Meulen, B. D. Jager, E. Noll, F. Veldpaus, F. Sluis, M. Steinbuch","doi":"10.1109/CCA.2009.5281021","DOIUrl":"https://doi.org/10.1109/CCA.2009.5281021","url":null,"abstract":"The control design for the variator in a pushbelt continuously variable transmission (CVT) is investigated. The variator enables a stepless variation of the transmission ratio within a finite range. A conventional control design for the variator is typically obtained by the use of a variator model, which incorporates large uncertainties and, therefore, limits the variator efficiency. In this paper, a control design for the variator is discussed, which improves the variator efficiency and limits the number of sensors. The relation between inputs and outputs of the variator is investigated, from which one input-output map is identified, which exhibits a maximum. This maximum indicates performance in terms of the variator efficiency. For this reason, this input-output map is maximized by means of extremum seeking control (ESC), which omits the use of a variator model. Experiments illustrate that the approach is feasible and show that a conventional control design for the variator is outperformed.","PeriodicalId":294950,"journal":{"name":"2009 IEEE Control Applications, (CCA) & Intelligent Control, (ISIC)","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134238708","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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