Pub Date : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6687979
Zhenghao Zhang, Husheng Li, J. Song, Zhu Han, G. Luo, W. Hu
Protective relay is used to protect power systems. The main requirements on protective relays are selectivity, reliability and speed. Differential relay, which is based on the measurements of currents and the exchange of messages among relays, is the most reliable one among all types of protective relays. Wireless communication is proposed for the information exchange in the differential relay. Based on the communication network among relays, a generalized differential relay scheme is proposed to incorporate secondary relays. The mathematical tool of Petri net is used to model the wireless communication based differential relay scheme. The problem of resource allocation for the wireless communication network is studied in order to maximize the system reliability, based on the Petri net modeling. Numerical simulations have demonstrated the validity of the proposed relay scheme.
{"title":"Wireless communication aided differential relay protection in smart grids: A concerted blitzkrieg","authors":"Zhenghao Zhang, Husheng Li, J. Song, Zhu Han, G. Luo, W. Hu","doi":"10.1109/SmartGridComm.2013.6687979","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6687979","url":null,"abstract":"Protective relay is used to protect power systems. The main requirements on protective relays are selectivity, reliability and speed. Differential relay, which is based on the measurements of currents and the exchange of messages among relays, is the most reliable one among all types of protective relays. Wireless communication is proposed for the information exchange in the differential relay. Based on the communication network among relays, a generalized differential relay scheme is proposed to incorporate secondary relays. The mathematical tool of Petri net is used to model the wireless communication based differential relay scheme. The problem of resource allocation for the wireless communication network is studied in order to maximize the system reliability, based on the Petri net modeling. Numerical simulations have demonstrated the validity of the proposed relay scheme.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131712207","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6687973
Mehdi Korki, Cisheng Zhang, H. Vu
In this paper, we evaluate the performance of a popular narrow band power line communication (PLC) solution (referred to as PoweRline Intelligent Metering Evolution or PRIME) for smart grid applications in an impulsive noise environment. To this end, we analyze the effects of the impulsive noise in narrow band PLC systems and derive an explicit formula of bit error rate (BER) and its upper bound for an uncoded and coded orthogonal frequency division multiplexing (OFDM) schemes in PRIME, respectively. Our analyses and the upper bound are then validated using simulation. Furthermore, we propose an efficient time domain interleaver (TDI) technique to improve the performance of the PRIME by spreading the effect of impulsive bursts over a large number of OFDM symbols. Our simulation results show that the TDI method significantly reduces the impact of impulsive noises on the BER of the PRIME solution.
{"title":"Performance evaluation of PRIME in smart grid","authors":"Mehdi Korki, Cisheng Zhang, H. Vu","doi":"10.1109/SmartGridComm.2013.6687973","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6687973","url":null,"abstract":"In this paper, we evaluate the performance of a popular narrow band power line communication (PLC) solution (referred to as PoweRline Intelligent Metering Evolution or PRIME) for smart grid applications in an impulsive noise environment. To this end, we analyze the effects of the impulsive noise in narrow band PLC systems and derive an explicit formula of bit error rate (BER) and its upper bound for an uncoded and coded orthogonal frequency division multiplexing (OFDM) schemes in PRIME, respectively. Our analyses and the upper bound are then validated using simulation. Furthermore, we propose an efficient time domain interleaver (TDI) technique to improve the performance of the PRIME by spreading the effect of impulsive bursts over a large number of OFDM symbols. Our simulation results show that the TDI method significantly reduces the impact of impulsive noises on the BER of the PRIME solution.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125208587","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6688006
Kelsey Cairns, C. Hauser, T. Gamage
This paper explores Time-Valid One-Time-Signature (TV-OTS) as a data authentication protocol for potential use in smart grid applications. TV-OTS is highly configurable with computationally lightweight signing and verification processes, making it a strong candidate for smart grid use. A detailed analysis of security against brute force attacks is presented, which is critical to understanding the parameters under which TV-OTS is reliably secure. This analysis is used to choose applicable parameters for latency tests of a full TV-OTS implementation. Performance results are favorable, with the cost of combined signing and verifying reaching under 10 milliseconds.
本文探讨了Time-Valid one - time signature (TV-OTS)作为一种数据认证协议在智能电网应用中的潜在应用。TV-OTS具有高度可配置的计算轻量级签名和验证过程，使其成为智能电网使用的有力候选者。详细分析了针对暴力攻击的安全性，这对于理解TV-OTS可靠安全的参数至关重要。此分析用于为完整TV-OTS实现的延迟测试选择适用的参数。性能结果很好，联合签名和验证的成本低于10毫秒。
{"title":"Flexible data authentication evaluated for the smart grid","authors":"Kelsey Cairns, C. Hauser, T. Gamage","doi":"10.1109/SmartGridComm.2013.6688006","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6688006","url":null,"abstract":"This paper explores Time-Valid One-Time-Signature (TV-OTS) as a data authentication protocol for potential use in smart grid applications. TV-OTS is highly configurable with computationally lightweight signing and verification processes, making it a strong candidate for smart grid use. A detailed analysis of security against brute force attacks is presented, which is critical to understanding the parameters under which TV-OTS is reliably secure. This analysis is used to choose applicable parameters for latency tests of a full TV-OTS implementation. Performance results are favorable, with the cost of combined signing and verifying reaching under 10 milliseconds.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130771249","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6688028
T. Ropitault, A. Lampropulos, Ramanuja Vedantham, Philippe Chiummiento Itron
Advanced Metering Infrastructure (AMI) is a key enabler of the Smart Grid. Narrowband Power Line Communication (PLC) technology is currently the preferred choice for many AMI use cases. Different PHY/MAC standards and dedicated routing protocols are emerging. New trustworthy models and simulation tools are needed for their evaluation in large scale deployments. This paper presents a realistic model for the latest generation of OFDM-based narrowband PLC standards. The model has been implemented in a popular network simulator - OPNET. Furthermore, the model and the simulator are validated against a real-world testbed. Finally, we present the calibration process and the scalability of the simulator. The results show that it is possible to simulate large topologies of up to 1000 smart meters under a proactive (RPL) or reactive (LOAD) packet routing.
{"title":"Realistic model for narrowband PLC for advanced metering infrastructure","authors":"T. Ropitault, A. Lampropulos, Ramanuja Vedantham, Philippe Chiummiento Itron","doi":"10.1109/SmartGridComm.2013.6688028","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6688028","url":null,"abstract":"Advanced Metering Infrastructure (AMI) is a key enabler of the Smart Grid. Narrowband Power Line Communication (PLC) technology is currently the preferred choice for many AMI use cases. Different PHY/MAC standards and dedicated routing protocols are emerging. New trustworthy models and simulation tools are needed for their evaluation in large scale deployments. This paper presents a realistic model for the latest generation of OFDM-based narrowband PLC standards. The model has been implemented in a popular network simulator - OPNET. Furthermore, the model and the simulator are validated against a real-world testbed. Finally, we present the calibration process and the scalability of the simulator. The results show that it is possible to simulate large topologies of up to 1000 smart meters under a proactive (RPL) or reactive (LOAD) packet routing.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127851716","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6687925
V. Arya, R. Mitra
We present a novel technique to infer connectivity relationships corresponding a set of measurement or monitoring locations in a distribution grid. Our approach uses a time series of voltage measurements from each location and partitions these into clusters based on whether the locations belong to same or different sub-circuits in the grid. For instance, customer meters connected to the same phase may be clustered into one group. The methods allow distributors to verify the connectivity model of their distribution network and also improve its accuracy. Furthermore, the methods support incremental meter deployment and can be applied to any subset of measurement locations. We present initial experimental results with the help of real voltage time series measurements collected from a microgrid.
{"title":"Voltage-based clustering to identify connectivity relationships in distribution networks","authors":"V. Arya, R. Mitra","doi":"10.1109/SmartGridComm.2013.6687925","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6687925","url":null,"abstract":"We present a novel technique to infer connectivity relationships corresponding a set of measurement or monitoring locations in a distribution grid. Our approach uses a time series of voltage measurements from each location and partitions these into clusters based on whether the locations belong to same or different sub-circuits in the grid. For instance, customer meters connected to the same phase may be clustered into one group. The methods allow distributors to verify the connectivity model of their distribution network and also improve its accuracy. Furthermore, the methods support incremental meter deployment and can be applied to any subset of measurement locations. We present initial experimental results with the help of real voltage time series measurements collected from a microgrid.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121175420","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6687987
A. Goodney, Saurabh Kumar, Akshay Ravi, Young H. Cho
An important goal for the smart grid is to give power grid operators like utilities a global view of the health of the power grid. As the smart grid is built-out, the size and complexity of the required communications network is increasing. In this paper we propose using software defined networks (SDN) for the smart grid, as SDN allow for a flexibly defined network (through programmability) along with superior performance and implementations based on industry standards. To demonstrate that SDN can be used as the underlying technology for power grid networking we have implemented a multi-rate, multicast network for phasor measurement unit (PMU) data. We compare the SDN solution to the conventional approach as well as two other advanced PMU networking methods, IP Multicast and GridStat and show that our method achieves lower latency and optimal network utilization.
{"title":"Efficient PMU networking with software defined networks","authors":"A. Goodney, Saurabh Kumar, Akshay Ravi, Young H. Cho","doi":"10.1109/SmartGridComm.2013.6687987","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6687987","url":null,"abstract":"An important goal for the smart grid is to give power grid operators like utilities a global view of the health of the power grid. As the smart grid is built-out, the size and complexity of the required communications network is increasing. In this paper we propose using software defined networks (SDN) for the smart grid, as SDN allow for a flexibly defined network (through programmability) along with superior performance and implementations based on industry standards. To demonstrate that SDN can be used as the underlying technology for power grid networking we have implemented a multi-rate, multicast network for phasor measurement unit (PMU) data. We compare the SDN solution to the conventional approach as well as two other advanced PMU networking methods, IP Multicast and GridStat and show that our method achieves lower latency and optimal network utilization.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132613175","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6688042
Zhenzhou Peng, Shinjae Yoo, Dantong Yu, D. Huang
Solar irradiance variability, left unmitigated, will threat the stability of grid system, and might incur significant economical impacts. This paper focuses on a pipeline to predict solar irradiance from 30 minutes to 5 hours using geostationary satellite. It consists of two parts: cloud motion estimation and solar irradiance prediction using the estimated satellite images. The main challenge is image noise at all levels of processing from motion estimation to irradiance prediction. To overcome this problem, we propose to use optical flow motion estimation, and subsequently combine multiple evidences together using robust support vector regression (SVR). Our systematic evaluation shows significant improvements over the baseline in both motion estimation and irradiance prediction.
{"title":"Solar irradiance forecast system based on geostationary satellite","authors":"Zhenzhou Peng, Shinjae Yoo, Dantong Yu, D. Huang","doi":"10.1109/SmartGridComm.2013.6688042","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6688042","url":null,"abstract":"Solar irradiance variability, left unmitigated, will threat the stability of grid system, and might incur significant economical impacts. This paper focuses on a pipeline to predict solar irradiance from 30 minutes to 5 hours using geostationary satellite. It consists of two parts: cloud motion estimation and solar irradiance prediction using the estimated satellite images. The main challenge is image noise at all levels of processing from motion estimation to irradiance prediction. To overcome this problem, we propose to use optical flow motion estimation, and subsequently combine multiple evidences together using robust support vector regression (SVR). Our systematic evaluation shows significant improvements over the baseline in both motion estimation and irradiance prediction.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115489921","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6688008
Xuelian Long, D. Tipper, Y. Qian
In the smart grid, collecting data from remote sensors and meters such as phasor measurement units (PMUs) can help ensure safe and reliable operation, avoiding overloads and outages. Since such data is related to critical operation of the power grid, appropriate security schemes should be utilized for secure communications among the components in the smart grid. This paper proposes a key management scheme for secure data communications in a smart grid system. It is a versatile key management scheme in that it can support unicast, multicast and broadcast communications. Moreover, the proposed scheme can be tailored to the hierarchical control system structure of the smart grid. A comparative security cost analysis is performed to illustrate that the proposed scheme can achieve efficient key management.
{"title":"An advanced key management scheme for secure smart grid communications","authors":"Xuelian Long, D. Tipper, Y. Qian","doi":"10.1109/SmartGridComm.2013.6688008","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6688008","url":null,"abstract":"In the smart grid, collecting data from remote sensors and meters such as phasor measurement units (PMUs) can help ensure safe and reliable operation, avoiding overloads and outages. Since such data is related to critical operation of the power grid, appropriate security schemes should be utilized for secure communications among the components in the smart grid. This paper proposes a key management scheme for secure data communications in a smart grid system. It is a versatile key management scheme in that it can support unicast, multicast and broadcast communications. Moreover, the proposed scheme can be tailored to the hierarchical control system structure of the smart grid. A comparative security cost analysis is performed to illustrate that the proposed scheme can achieve efficient key management.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115026428","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6687967
Gaurav Sharma, Le Xie, P. Kumar
In this paper, we formulate and analyze the optimal set point problem of thermostatically controlled loads in a smart microgrid environment. From an aggregator's perspective, we show that flexibility can be extracted from the thermal inertia embedded in residential customers and be leveraged for maximum utilization of variable generation such as wind and solar. Through rigorous theoretical results we show that there is a fully decentralized mechanism for setting individual household temperature bounds while (a) maximum flexibility is extracted from inertial loads to balance the stochastic generation; (b) optimal staggering of demand responses of inertial loads can be achieved for smoothing out the overall power consumption; and (c) individual customers' comfort zone is taken into account. An easy-to-implement practical control setting is also introduced and tested using a simple model of wind and load distribution.
{"title":"Large population optimal demand response for thermostatically controlled inertial loads","authors":"Gaurav Sharma, Le Xie, P. Kumar","doi":"10.1109/SmartGridComm.2013.6687967","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6687967","url":null,"abstract":"In this paper, we formulate and analyze the optimal set point problem of thermostatically controlled loads in a smart microgrid environment. From an aggregator's perspective, we show that flexibility can be extracted from the thermal inertia embedded in residential customers and be leveraged for maximum utilization of variable generation such as wind and solar. Through rigorous theoretical results we show that there is a fully decentralized mechanism for setting individual household temperature bounds while (a) maximum flexibility is extracted from inertial loads to balance the stochastic generation; (b) optimal staggering of demand responses of inertial loads can be achieved for smoothing out the overall power consumption; and (c) individual customers' comfort zone is taken into account. An easy-to-implement practical control setting is also introduced and tested using a simple model of wind and load distribution.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115742434","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 : 2013-12-19DOI: 10.1109/SmartGridComm.2013.6688047
M. Zadeh, Reza Parseh, M. Molinas, K. Kansanen
Control and stability of power electronic converters is the main issue regarding the secure integration of distributed energy resources into the smart grid. In this paper, a centralized controller for a multi-converter system with a wireless communication channel in the feedback loop is modelled and simulated entirely. The wideband communication system is needed in order to guarantee the flexibility and robustness of the control system in both transient and dynamic performance. Therefore, it should be modelled together with the controller system as a communication-control system. The detailed model of voltage source converters (VSCs) is considered as well as communication system components in order to investigate the stability of power electronics systems in presence of a communication system in the feedback loop of the controller. The communication system elements such as noise, delay, and level of distortion due to quantization are selected to realistically model a practical situation.
{"title":"Modeling and simulation of wireless communication based robust controller for multi-converter systems","authors":"M. Zadeh, Reza Parseh, M. Molinas, K. Kansanen","doi":"10.1109/SmartGridComm.2013.6688047","DOIUrl":"https://doi.org/10.1109/SmartGridComm.2013.6688047","url":null,"abstract":"Control and stability of power electronic converters is the main issue regarding the secure integration of distributed energy resources into the smart grid. In this paper, a centralized controller for a multi-converter system with a wireless communication channel in the feedback loop is modelled and simulated entirely. The wideband communication system is needed in order to guarantee the flexibility and robustness of the control system in both transient and dynamic performance. Therefore, it should be modelled together with the controller system as a communication-control system. The detailed model of voltage source converters (VSCs) is considered as well as communication system components in order to investigate the stability of power electronics systems in presence of a communication system in the feedback loop of the controller. The communication system elements such as noise, delay, and level of distortion due to quantization are selected to realistically model a practical situation.","PeriodicalId":136434,"journal":{"name":"2013 IEEE International Conference on Smart Grid Communications (SmartGridComm)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116147329","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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