Pub Date : 2015-12-01DOI: 10.1109/ICMIC.2015.7409493
Y. Li, Xueli Wu, Jianhua Zhang, Quanmin Zhu
In this paper, the problem of sliding mode control of a discrete-time switched system with uncertain parameters and time-varying delay is investigated. By using the average dwell time approach and the piecewise Lyapunov function technique, a sufficient condition is proposed to guarantee the exponential stability of the switched systems with uncertain parameters and time delays. The conservation of the obtained results is reduced by employing the delay partitioning method and the free-weighting matrix technique. A robust sliding mode controller has been designed to force the closed-loop system to be driven onto a prescribed sliding surface and maintained there for all subsequent time. Finally, a numerical example is given to illustrate the effectiveness of the proposed theory.
{"title":"Sliding mode control for discrete time switched systems with uncertain parameters and time delay","authors":"Y. Li, Xueli Wu, Jianhua Zhang, Quanmin Zhu","doi":"10.1109/ICMIC.2015.7409493","DOIUrl":"https://doi.org/10.1109/ICMIC.2015.7409493","url":null,"abstract":"In this paper, the problem of sliding mode control of a discrete-time switched system with uncertain parameters and time-varying delay is investigated. By using the average dwell time approach and the piecewise Lyapunov function technique, a sufficient condition is proposed to guarantee the exponential stability of the switched systems with uncertain parameters and time delays. The conservation of the obtained results is reduced by employing the delay partitioning method and the free-weighting matrix technique. A robust sliding mode controller has been designed to force the closed-loop system to be driven onto a prescribed sliding surface and maintained there for all subsequent time. Finally, a numerical example is given to illustrate the effectiveness of the proposed theory.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122582000","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 : 2014-12-25DOI: 10.1109/CCDC.2014.6852245
Jiuqiang Xu, Jinfa Wang, Hai Zhao, Siyuan Jia
Network science have constantly been in the focus of research for the last decade, with considerable advances in the controllability of their structural. However, much less effort has been devoted to study that how to improve the controllability of complex networks. In this paper, a new algorithm is proposed to improve the controllability of complex networks by rewiring links regularly which transforms the network structure. Then it is demonstrated that our algorithm is very effective after numerical simulation experiment on typical network models (Erdös-Rényi and scale-free network). We find that our algorithm is mainly determined by the average degree and positive correlation of in-degree and out-degree of network and it has nothing to do with the network size. Furthermore, we analyze and discuss the correlation between controllability of complex networks and degree distribution index: power-law exponent and heterogeneity.
{"title":"Improving controllability of complex networks by rewiring links regularly","authors":"Jiuqiang Xu, Jinfa Wang, Hai Zhao, Siyuan Jia","doi":"10.1109/CCDC.2014.6852245","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852245","url":null,"abstract":"Network science have constantly been in the focus of research for the last decade, with considerable advances in the controllability of their structural. However, much less effort has been devoted to study that how to improve the controllability of complex networks. In this paper, a new algorithm is proposed to improve the controllability of complex networks by rewiring links regularly which transforms the network structure. Then it is demonstrated that our algorithm is very effective after numerical simulation experiment on typical network models (Erdös-Rényi and scale-free network). We find that our algorithm is mainly determined by the average degree and positive correlation of in-degree and out-degree of network and it has nothing to do with the network size. Furthermore, we analyze and discuss the correlation between controllability of complex networks and degree distribution index: power-law exponent and heterogeneity.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134456518","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6852770
L. Long
In direct drive XY table system, due to the load disturbance and parameter variation and parameter mismatch between the two axis of uncertainty factors will affect the contour machining precision, adaptive zero phase error tracking controller (ZPETC) combined with internal model control (IMC) control strategy is presented to control the tracking error, and cross-coupling control method is used to coordinate the movement of two axis control in order to improve the contour machining precision, thus to achieve the tracking error and contour error decreases at the same time. Adaptive ZPETC for a given trajectory has better tracking performance. Internal model control has good tracking of regulatory, the advantages of strong robustness, can eliminate the interference of unpredictable. The cross coupling control (CCC) method can effectively realize the dynamic contour error compensation, make the contour error minimum. The simulation results show that the designed control system has good tracking and robustness, can effectively improve the tracking accuracy and the contour accuracy.
{"title":"Adaptive zero phase based internal model control for direct drive XY table","authors":"L. Long","doi":"10.1109/CCDC.2014.6852770","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852770","url":null,"abstract":"In direct drive XY table system, due to the load disturbance and parameter variation and parameter mismatch between the two axis of uncertainty factors will affect the contour machining precision, adaptive zero phase error tracking controller (ZPETC) combined with internal model control (IMC) control strategy is presented to control the tracking error, and cross-coupling control method is used to coordinate the movement of two axis control in order to improve the contour machining precision, thus to achieve the tracking error and contour error decreases at the same time. Adaptive ZPETC for a given trajectory has better tracking performance. Internal model control has good tracking of regulatory, the advantages of strong robustness, can eliminate the interference of unpredictable. The cross coupling control (CCC) method can effectively realize the dynamic contour error compensation, make the contour error minimum. The simulation results show that the designed control system has good tracking and robustness, can effectively improve the tracking accuracy and the contour accuracy.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115396718","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6852337
Xinsheng Wang, Huaqiang Zhang, Changxi Li
In this paper, a distributed attitude consensus tracking control law is proposed for satellite formation flying by using sliding mode method. First, graph theory and Modified Rodriguez Parameters (MRPs) are introduced to describe the relation and dynamics of the team. Second, distributed terminal sliding mode observers are constructed to estimate the velocity state of rigid bodies in the team. The observer error will converge to zero in finite time. Then, an attitude consensus tracking control law based on sliding mode method is discussed, using the estimated states by the proposed observers. The control law can ensure not only attitude agreement between rigid bodies in the team but also time-varying reference tracking without velocity measurements. Finally, an illustrative example shows that the attitude tracking goal will achieve with the velocity-free consensus control strategy.
{"title":"Finite-time attitude consensus tracking with terminal sliding mode observer","authors":"Xinsheng Wang, Huaqiang Zhang, Changxi Li","doi":"10.1109/CCDC.2014.6852337","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852337","url":null,"abstract":"In this paper, a distributed attitude consensus tracking control law is proposed for satellite formation flying by using sliding mode method. First, graph theory and Modified Rodriguez Parameters (MRPs) are introduced to describe the relation and dynamics of the team. Second, distributed terminal sliding mode observers are constructed to estimate the velocity state of rigid bodies in the team. The observer error will converge to zero in finite time. Then, an attitude consensus tracking control law based on sliding mode method is discussed, using the estimated states by the proposed observers. The control law can ensure not only attitude agreement between rigid bodies in the team but also time-varying reference tracking without velocity measurements. Finally, an illustrative example shows that the attitude tracking goal will achieve with the velocity-free consensus control strategy.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124386297","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6852623
Longhu Quan, Zhanshan Wang, Xiuchong Liu
This paper provides an improvement in sensorless control performance of surface permanent magnet synchronous motor(SPMSM). One method of the rotor position estimation by the complex number model based position estimator is proposed for the sensorless control of SPMSM. And, in order to eliminate the position estimation error that may be occurred by the uncertainty of motor parameters, a position type PI controller is applied to the error part of the position estimator. The proposed position estimation method does not need any information about the mechanical system of a motor. A control scheme to identify the permanent magnet flux of SPMSM by Extended Kalman Filter(EKF) is also proposed to increase the rotor position estimation accuracy. A rotor-flux-oriented vector control is employed as the basic control strategy for SPMSM drive system. The simulation results demonstrated the validity and feasibility of the proposed control system.
{"title":"Sensorless control of SPMSM using complex number model based position estimation and EKF","authors":"Longhu Quan, Zhanshan Wang, Xiuchong Liu","doi":"10.1109/CCDC.2014.6852623","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852623","url":null,"abstract":"This paper provides an improvement in sensorless control performance of surface permanent magnet synchronous motor(SPMSM). One method of the rotor position estimation by the complex number model based position estimator is proposed for the sensorless control of SPMSM. And, in order to eliminate the position estimation error that may be occurred by the uncertainty of motor parameters, a position type PI controller is applied to the error part of the position estimator. The proposed position estimation method does not need any information about the mechanical system of a motor. A control scheme to identify the permanent magnet flux of SPMSM by Extended Kalman Filter(EKF) is also proposed to increase the rotor position estimation accuracy. A rotor-flux-oriented vector control is employed as the basic control strategy for SPMSM drive system. The simulation results demonstrated the validity and feasibility of the proposed control system.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123048036","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6852910
Pengfei Wang, Huifang Li, Baihai Zhang
Context-aware workflow systems can adapt their behavior based on the changes of real world, which is often gathered by a big amount of sensors. Thus, the modeling of context-aware workflow is the key issue in context-aware workflow systems, because context information is often varied and complex. To better describe context information in business processes, this paper proposes an OWL-based (Web Ontology Language) approach to model context-aware workflows. The context model and process model elements is defined based on OWL, so it can not only express the context information involved in business processes but also the corresponding workflow control items as OWL. The modeling rules which make the model more normalized are also designed. Case study and analysis show that our approach has good adaptability, and can be used to easily describe any sophisticated context-aware workflows.
{"title":"Context-aware workflow modeling approach using OWL","authors":"Pengfei Wang, Huifang Li, Baihai Zhang","doi":"10.1109/CCDC.2014.6852910","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852910","url":null,"abstract":"Context-aware workflow systems can adapt their behavior based on the changes of real world, which is often gathered by a big amount of sensors. Thus, the modeling of context-aware workflow is the key issue in context-aware workflow systems, because context information is often varied and complex. To better describe context information in business processes, this paper proposes an OWL-based (Web Ontology Language) approach to model context-aware workflows. The context model and process model elements is defined based on OWL, so it can not only express the context information involved in business processes but also the corresponding workflow control items as OWL. The modeling rules which make the model more normalized are also designed. Case study and analysis show that our approach has good adaptability, and can be used to easily describe any sophisticated context-aware workflows.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121083846","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6853003
Degang Xu, Xiyang Xu
Transmission dynamics has become one hot issue in complex systems and complex networks. It is very urgent to study the influences on the communication process based on the network topology structure. This paper focuses on modeling and control strategy of epidemic transmission SIR (Susceptible-Infected-Recovered) with community structure of networks. Firstly, network community structure features are considered into the classical SIR model by analyzing the characteristic of complex dynamic network. A new modified SIR model with community structure parameters is proposed. The influence of network community structure on epidemic spread is analyzed by numerical simulation. Furthermore, this paper proposes three different control strategies for dynamic network SIR with community structure. These control strategies include random immunization, target immunization strategy and quarantine strategy by different infected parameters and initial value. Numerical simulation shows the validity of our proposed strategies. The research result is very significant for epidemic spreading and control.
{"title":"Modeling and control of dynamic network SIR based on community structure*","authors":"Degang Xu, Xiyang Xu","doi":"10.1109/CCDC.2014.6853003","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6853003","url":null,"abstract":"Transmission dynamics has become one hot issue in complex systems and complex networks. It is very urgent to study the influences on the communication process based on the network topology structure. This paper focuses on modeling and control strategy of epidemic transmission SIR (Susceptible-Infected-Recovered) with community structure of networks. Firstly, network community structure features are considered into the classical SIR model by analyzing the characteristic of complex dynamic network. A new modified SIR model with community structure parameters is proposed. The influence of network community structure on epidemic spread is analyzed by numerical simulation. Furthermore, this paper proposes three different control strategies for dynamic network SIR with community structure. These control strategies include random immunization, target immunization strategy and quarantine strategy by different infected parameters and initial value. Numerical simulation shows the validity of our proposed strategies. The research result is very significant for epidemic spreading and control.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127300614","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6852533
Zhan Yu-ting, Tan Zhi
Network node positioning technology is one of the important supporting technologies in the practical application of wireless sensor. In order to overcome the measurement error of the least squares method for wireless sensor networks (WSNs) node affect their positioning accuracy, an improved positioning algorithm least squares(LS) is proposed. In order to obtain the optimal reference node, the algorithm based on the conventional least squares location algorithm to correct bad nodes. The simulation results show that the algorithm can effectively filter large node localization errors. The positioning accuracy is significantly improved.
{"title":"Optimization of least-squares localization algorithm in WSN","authors":"Zhan Yu-ting, Tan Zhi","doi":"10.1109/CCDC.2014.6852533","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852533","url":null,"abstract":"Network node positioning technology is one of the important supporting technologies in the practical application of wireless sensor. In order to overcome the measurement error of the least squares method for wireless sensor networks (WSNs) node affect their positioning accuracy, an improved positioning algorithm least squares(LS) is proposed. In order to obtain the optimal reference node, the algorithm based on the conventional least squares location algorithm to correct bad nodes. The simulation results show that the algorithm can effectively filter large node localization errors. The positioning accuracy is significantly improved.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124875323","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6852794
Ting-Feng Zhang, Zhizhong Mao, Ping Yuan
Implementation of a decoupled PID control strategy to a wind tunnel control system is described in this paper. Two coupled variables, stagnation pressure and Mach number, are controlled in the wind tunnel system. The wind tunnel exhibits common features of industrial systems including non-linear dynamics, time delay and coupling effects among variables. A decoupler is first introduced in this control scheme. Next, a reduced order model is determined for the decoupled wind tunnel process. Then, the PID controller is obtained using the non-dimensional tuning (NDT) algorithm. Simulation experiments have confirmed good regulatory and tracking properties of the proposed control system.
{"title":"Decoupled PID controller for wind tunnel system","authors":"Ting-Feng Zhang, Zhizhong Mao, Ping Yuan","doi":"10.1109/CCDC.2014.6852794","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852794","url":null,"abstract":"Implementation of a decoupled PID control strategy to a wind tunnel control system is described in this paper. Two coupled variables, stagnation pressure and Mach number, are controlled in the wind tunnel system. The wind tunnel exhibits common features of industrial systems including non-linear dynamics, time delay and coupling effects among variables. A decoupler is first introduced in this control scheme. Next, a reduced order model is determined for the decoupled wind tunnel process. Then, the PID controller is obtained using the non-dimensional tuning (NDT) algorithm. Simulation experiments have confirmed good regulatory and tracking properties of the proposed control system.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125825460","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 : 2014-07-14DOI: 10.1109/CCDC.2014.6852896
Xiaoguang Han, Jigang Sun, Wu Qu, Xuanxia Yao
A number of techniques have been devised by researchers to counter malware attacks, and machine learning techniques play an important role in automated malware detection. Several machine learning approaches have been applied to malware detection, based on different features derived from dynamic analysis of the malware. While these methods demonstrate promise, they pose at least two major challenges. First, these approaches are subjected to a growing array of countermeasures that increase the cost of capturing these malware binary executable file features. Further, feature extraction requires a time investment per binary file that does not scale well to the daily volume of malware instances being reported by those who diligently collect malware. In order to address the first challenge, this article proposed a binary-to-image projection algorithm based on a new type of feature extraction for the malware, was introduced in [2]. To address the second challenge, the technique's scalability is demonstrated through an implementation for the distributed (Key, Value) abstraction in cloud computing environment. Both theoretical and empirical evidence demonstrate its effectiveness over other state-of-the-art malware detection techniques on malware corpus, and the proposed method could be a useful and efficient complement to dynamic analysis.
{"title":"Distributed malware detection based on binary file features in cloud computing environment","authors":"Xiaoguang Han, Jigang Sun, Wu Qu, Xuanxia Yao","doi":"10.1109/CCDC.2014.6852896","DOIUrl":"https://doi.org/10.1109/CCDC.2014.6852896","url":null,"abstract":"A number of techniques have been devised by researchers to counter malware attacks, and machine learning techniques play an important role in automated malware detection. Several machine learning approaches have been applied to malware detection, based on different features derived from dynamic analysis of the malware. While these methods demonstrate promise, they pose at least two major challenges. First, these approaches are subjected to a growing array of countermeasures that increase the cost of capturing these malware binary executable file features. Further, feature extraction requires a time investment per binary file that does not scale well to the daily volume of malware instances being reported by those who diligently collect malware. In order to address the first challenge, this article proposed a binary-to-image projection algorithm based on a new type of feature extraction for the malware, was introduced in [2]. To address the second challenge, the technique's scalability is demonstrated through an implementation for the distributed (Key, Value) abstraction in cloud computing environment. Both theoretical and empirical evidence demonstrate its effectiveness over other state-of-the-art malware detection techniques on malware corpus, and the proposed method could be a useful and efficient complement to dynamic analysis.","PeriodicalId":380818,"journal":{"name":"The 26th Chinese Control and Decision Conference (2014 CCDC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125900955","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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