Pub Date : 2014-12-01DOI: 10.1109/APPEEC.2014.7066126
Jinli Zhao, Kai Yuan, Peng Li, H. Ji, Chengdi Ding, Maosheng Ding
The dynamic characteristics of active distribution networks (ADNs) need to be concerned if a large number of distributed generators are connected. A highly efficient and reliable simulation algorithm with good numerical stability is therefore essential for the stability analysis of ADNs. This paper proposes a novel dynamic simulation algorithm of ADNs based on the implicit projective method, which is a second order integration algorithm. The proposed method is an equivalent A-Stable method and the calculation efficiency is increased significantly compared with the traditional integration algorithms. It is especially suitable for the dynamic simulation and stability analysis of the ADNs with a large number of DGs. Case studies based on the IEEE 123-node test feeder show the feasibility and effectiveness of the proposed method, which is verified through the comparison with the commercial simulation tool DIgSI-LENT/PowerFactory and the traditional trapezoidal method.
{"title":"An equivalent A-Stable dynamic simulation algorithm of active distribution networks based on the implicit projective method","authors":"Jinli Zhao, Kai Yuan, Peng Li, H. Ji, Chengdi Ding, Maosheng Ding","doi":"10.1109/APPEEC.2014.7066126","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066126","url":null,"abstract":"The dynamic characteristics of active distribution networks (ADNs) need to be concerned if a large number of distributed generators are connected. A highly efficient and reliable simulation algorithm with good numerical stability is therefore essential for the stability analysis of ADNs. This paper proposes a novel dynamic simulation algorithm of ADNs based on the implicit projective method, which is a second order integration algorithm. The proposed method is an equivalent A-Stable method and the calculation efficiency is increased significantly compared with the traditional integration algorithms. It is especially suitable for the dynamic simulation and stability analysis of the ADNs with a large number of DGs. Case studies based on the IEEE 123-node test feeder show the feasibility and effectiveness of the proposed method, which is verified through the comparison with the commercial simulation tool DIgSI-LENT/PowerFactory and the traditional trapezoidal method.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128875449","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066057
Cong Zhang, Haoyong Chen, Xuanhao Xu, R. Cai
In this paper, we are aimed to search the Pareto front of multi-objective optimal reactive power dispatch by the primal dual interior point method. In the front part are the introductions of optimal reactive power dispatch model, the concepts of Pareto optimum solution and Pareto front, and the primal dual interior point method. In the rear part, the process of searching Pareto front will be presented, followed by the case study which consists of three cases. By conducting case study, we concludes that the primal dual interior point method performs effectively as well as efficiently in searching the Pareto front of multi-objective optimal reactive power dispatch.
{"title":"Pareto front of multi-objective optimal reactive power dispatch","authors":"Cong Zhang, Haoyong Chen, Xuanhao Xu, R. Cai","doi":"10.1109/APPEEC.2014.7066057","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066057","url":null,"abstract":"In this paper, we are aimed to search the Pareto front of multi-objective optimal reactive power dispatch by the primal dual interior point method. In the front part are the introductions of optimal reactive power dispatch model, the concepts of Pareto optimum solution and Pareto front, and the primal dual interior point method. In the rear part, the process of searching Pareto front will be presented, followed by the case study which consists of three cases. By conducting case study, we concludes that the primal dual interior point method performs effectively as well as efficiently in searching the Pareto front of multi-objective optimal reactive power dispatch.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129071563","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066044
Haisheng Yang, Shengyang Lu
The optimization of the heating load operation of large co-generation units in thermal power plant was described, and the evaluation method of maximizing total relative economic benefit for thermal power plant was put forward. It is shown that this method can provide objective economic benefit of district heating operation conditions, and the benefit has no relationship with the concrete energy allocation method used for heating and electricity. It is shown that under the condition of boilers full load operation the optimized heating load scheme is related to the electric power response characteristics with change of the heating steam supply for the individual cogeneration unit. An example of heating load optimization for 2 existing 330MW cogeneration units was put forward in detail. It is shown that, the electric power response characteristics with change of the heating steam supply for the individual cogeneration unit, especially the slope of the characteristic curve determines the heating load optimization results. The cogeneration unit with lower changing slope should be dispatched in higher priority.
{"title":"Optimization of the heating load operation of large co-generation units in thermal power plant","authors":"Haisheng Yang, Shengyang Lu","doi":"10.1109/APPEEC.2014.7066044","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066044","url":null,"abstract":"The optimization of the heating load operation of large co-generation units in thermal power plant was described, and the evaluation method of maximizing total relative economic benefit for thermal power plant was put forward. It is shown that this method can provide objective economic benefit of district heating operation conditions, and the benefit has no relationship with the concrete energy allocation method used for heating and electricity. It is shown that under the condition of boilers full load operation the optimized heating load scheme is related to the electric power response characteristics with change of the heating steam supply for the individual cogeneration unit. An example of heating load optimization for 2 existing 330MW cogeneration units was put forward in detail. It is shown that, the electric power response characteristics with change of the heating steam supply for the individual cogeneration unit, especially the slope of the characteristic curve determines the heating load optimization results. The cogeneration unit with lower changing slope should be dispatched in higher priority.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129939628","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066001
Yuta Nakamura, Y. Mitsukuri, M. Iguchi, Y. Mishima, R. Hara, H. Kita
A surge of needs for the low carbon society promotes a spread of electric vehicle (EV). EVs could be charged at night simultaneously, as a result, severe voltage drop may happen. The authors have proposed the method which can compensate the voltage drop caused by EV charging by means of adjusting charging schedules and controlling reactive power. However, though the method can avoid the voltage violation, the method includes the inequality between EVs in other words, the only EV which is in terminal node in distribution system where voltage violation is likely to occur has to decrease charging power because the method is autonomous distributed control which is based on only self-voltage information. In this paper, we formulate a convenience loss of EV owner due to adjust reactive power and charging power. We propose a method to calculate the benefit of the EV owner and the cost needed by the voltage control using the EVs.
{"title":"Study of economic system at compensation for voltage drop utilizing charging power adjustment of electric vehicles","authors":"Yuta Nakamura, Y. Mitsukuri, M. Iguchi, Y. Mishima, R. Hara, H. Kita","doi":"10.1109/APPEEC.2014.7066001","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066001","url":null,"abstract":"A surge of needs for the low carbon society promotes a spread of electric vehicle (EV). EVs could be charged at night simultaneously, as a result, severe voltage drop may happen. The authors have proposed the method which can compensate the voltage drop caused by EV charging by means of adjusting charging schedules and controlling reactive power. However, though the method can avoid the voltage violation, the method includes the inequality between EVs in other words, the only EV which is in terminal node in distribution system where voltage violation is likely to occur has to decrease charging power because the method is autonomous distributed control which is based on only self-voltage information. In this paper, we formulate a convenience loss of EV owner due to adjust reactive power and charging power. We propose a method to calculate the benefit of the EV owner and the cost needed by the voltage control using the EVs.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121219823","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066096
Konstantinos Diakos, Qiuwei Wu, A. Nielsen
The main focus of the electrical engineers nowadays, is to develop a smart grid that is able to monitor, evaluate and control the power system operation. The integration of Intelligent Electronic Devices (IEDs) to the power network, is a strong indication of the inclination to lead the power network to a more reliable, secure and economic operation. The implementation of these devices though, demands the warranty of a secure operation and high-accuracy performance. This paper describes the procedure of establishing a PMU (Phasor Measurement Unit)-PDC (Phasor Data Concentrator) platform that is able to derive and communicate synchrophasor measurements of different parts of the power network and the development of tests, according to IEEE standards, that evaluate the performance of PMUs and PDCs. The tests are created by using a Real Time Digital Simulation (RTDS) system. The results obtained from testing are analyzed to evaluate the performance of the devices.
{"title":"Phasor measurement unit and phasor data concentrator test with real time digital simulator","authors":"Konstantinos Diakos, Qiuwei Wu, A. Nielsen","doi":"10.1109/APPEEC.2014.7066096","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066096","url":null,"abstract":"The main focus of the electrical engineers nowadays, is to develop a smart grid that is able to monitor, evaluate and control the power system operation. The integration of Intelligent Electronic Devices (IEDs) to the power network, is a strong indication of the inclination to lead the power network to a more reliable, secure and economic operation. The implementation of these devices though, demands the warranty of a secure operation and high-accuracy performance. This paper describes the procedure of establishing a PMU (Phasor Measurement Unit)-PDC (Phasor Data Concentrator) platform that is able to derive and communicate synchrophasor measurements of different parts of the power network and the development of tests, according to IEEE standards, that evaluate the performance of PMUs and PDCs. The tests are created by using a Real Time Digital Simulation (RTDS) system. The results obtained from testing are analyzed to evaluate the performance of the devices.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"2010 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121460962","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066179
Z. Zainal, S. Ang, M. Salam, Pg Jamra Weira, R. Goh
This paper presents a case study carried out on an existing 11 kV distribution network concerning the influence of different types of nonlinear loads namely switch mode power supply (SMPS), arc lighting (AL) and thyristor controlled reactor (TCR). The study also examines the effectiveness of mitigation to minimize the effect of harmonics by connecting a zigzag transformer into the system. The modeling work is carried by using simulation software called ERACS.
{"title":"Impacts of nonlinear loads on a 11 kV distribution network","authors":"Z. Zainal, S. Ang, M. Salam, Pg Jamra Weira, R. Goh","doi":"10.1109/APPEEC.2014.7066179","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066179","url":null,"abstract":"This paper presents a case study carried out on an existing 11 kV distribution network concerning the influence of different types of nonlinear loads namely switch mode power supply (SMPS), arc lighting (AL) and thyristor controlled reactor (TCR). The study also examines the effectiveness of mitigation to minimize the effect of harmonics by connecting a zigzag transformer into the system. The modeling work is carried by using simulation software called ERACS.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121495678","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066147
M. Q. Wang, X. S. Han, M. Yang, M. X. Wang
In this paper a mixed integer quadratic programming (MIQP) is proposed to solve the dynamic economic dispatch (DED) with valve-point effect (VPE), prohibited operation zones (POZs), and multiple fuel option (MFO). The non-convex, non-continuous cost functions caused by VPE, POZs, and MFO are piecewise linearized and solved by a MIQP. The effects of VPE, POZs, and MFO on the computation efficiency are analyzed. It shown that the VPE has much larger impact on the computation efficiency than POZs and MFO. The proposed method is tested on a 10-unit system.
{"title":"Dynamic economic dispatch with valve point effect, prohibited operation zones, and multiple fuel option","authors":"M. Q. Wang, X. S. Han, M. Yang, M. X. Wang","doi":"10.1109/APPEEC.2014.7066147","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066147","url":null,"abstract":"In this paper a mixed integer quadratic programming (MIQP) is proposed to solve the dynamic economic dispatch (DED) with valve-point effect (VPE), prohibited operation zones (POZs), and multiple fuel option (MFO). The non-convex, non-continuous cost functions caused by VPE, POZs, and MFO are piecewise linearized and solved by a MIQP. The effects of VPE, POZs, and MFO on the computation efficiency are analyzed. It shown that the VPE has much larger impact on the computation efficiency than POZs and MFO. The proposed method is tested on a 10-unit system.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121333578","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066186
W. Jing, Zhou Huizhi, L. Dichen, Guo Ke, Han Xiangyu
This paper proposes the MLR (multiple linear regression) algorithm for parameter estimation of power system post-fault configuration based on the PMU real-time measurement and generator dynamic equations. Using real-time data collected by wide-area measurement system, the algorithm can take complicated cascading fault events into consideration without any information about the specific parameter and fault type or structure of the power system. This attractive feature avoids the difficult problem to determine the parameter and the topology state of a transient event in actual projects, making it possible for the complex perturbed trajectories prediction. The proposed algorithm has been tested on various sample power systems with promising and accurate simulation results.
{"title":"Research on real-time admittance matrix identification based on WAMS and multiple linear regression","authors":"W. Jing, Zhou Huizhi, L. Dichen, Guo Ke, Han Xiangyu","doi":"10.1109/APPEEC.2014.7066186","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066186","url":null,"abstract":"This paper proposes the MLR (multiple linear regression) algorithm for parameter estimation of power system post-fault configuration based on the PMU real-time measurement and generator dynamic equations. Using real-time data collected by wide-area measurement system, the algorithm can take complicated cascading fault events into consideration without any information about the specific parameter and fault type or structure of the power system. This attractive feature avoids the difficult problem to determine the parameter and the topology state of a transient event in actual projects, making it possible for the complex perturbed trajectories prediction. The proposed algorithm has been tested on various sample power systems with promising and accurate simulation results.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122970778","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7065993
Lei Wang, C. Lam, M. Wong
This paper presents an adaptive hysteresis band controller for LC-coupling hybrid active power filter (HAPF) which can provide an approximate constant switching frequency. As the LC-coupling impendence can yield nonlinear compensating current slope, the conventional adaptive hysteresis band controller for linear L-coupling system like active power filter (APF) cannot be directly applied to nonlinear LC-coupling HAPF system. Owing to the circuit configuration of HAPF, its compensating current characteristic is firstly analyzed and discussed. The adaptive hysteresis band current controller for HAPF is then proposed by considering its nonlinear characteristic. Finally, to verify the performance of the proposed adaptive hysteresis band controller, simulation results are given in comparison with both conventional adaptive hysteresis band controller (developed for L-coupling system) and fixed hysteresis band controller for HAPF.
{"title":"An adaptive hysteresis band controller for LC-coupling hybrid active power filter with approximate constant switching frequency","authors":"Lei Wang, C. Lam, M. Wong","doi":"10.1109/APPEEC.2014.7065993","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7065993","url":null,"abstract":"This paper presents an adaptive hysteresis band controller for LC-coupling hybrid active power filter (HAPF) which can provide an approximate constant switching frequency. As the LC-coupling impendence can yield nonlinear compensating current slope, the conventional adaptive hysteresis band controller for linear L-coupling system like active power filter (APF) cannot be directly applied to nonlinear LC-coupling HAPF system. Owing to the circuit configuration of HAPF, its compensating current characteristic is firstly analyzed and discussed. The adaptive hysteresis band current controller for HAPF is then proposed by considering its nonlinear characteristic. Finally, to verify the performance of the proposed adaptive hysteresis band controller, simulation results are given in comparison with both conventional adaptive hysteresis band controller (developed for L-coupling system) and fixed hysteresis band controller for HAPF.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122644090","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 : 2014-12-01DOI: 10.1109/APPEEC.2014.7066087
Yanxia Chen, P. Zheng, Jinwen Sun, Xiangning Lin
As large-scaled electric vehicles (EVs) connecting to power distribution system via charging devices, the load of power system will get heaver in the foreseeable future. This will lead to an increasing risk for the security and stability of operation. Studying the quantitative influence that EV charging loads bring to the transient voltage stability of distribution system is of vital significance to analyze the security and stability status of power system after large-scaled EV loads are connected. Considering the torque-slip property of induction motor load, an index represented by relative value of slip considering induction motor loads is proposed in this paper, aiming at indicating the margin of transient voltage stability of distribution network. Furthermore, simulation analysis and calculations are carried out to study the transient voltage instability condition, and the focus of this paper is on the dispersed charging scenario of large-scaled EVs. The result shows that the index proposed is capable of reflecting the profound effect of large-scaled EV loads on the transient voltage security of distribution network.
{"title":"Study on the influence of large-scaled electric vehicle dispersed charging on transient voltage stability of distribution systems","authors":"Yanxia Chen, P. Zheng, Jinwen Sun, Xiangning Lin","doi":"10.1109/APPEEC.2014.7066087","DOIUrl":"https://doi.org/10.1109/APPEEC.2014.7066087","url":null,"abstract":"As large-scaled electric vehicles (EVs) connecting to power distribution system via charging devices, the load of power system will get heaver in the foreseeable future. This will lead to an increasing risk for the security and stability of operation. Studying the quantitative influence that EV charging loads bring to the transient voltage stability of distribution system is of vital significance to analyze the security and stability status of power system after large-scaled EV loads are connected. Considering the torque-slip property of induction motor load, an index represented by relative value of slip considering induction motor loads is proposed in this paper, aiming at indicating the margin of transient voltage stability of distribution network. Furthermore, simulation analysis and calculations are carried out to study the transient voltage instability condition, and the focus of this paper is on the dispersed charging scenario of large-scaled EVs. The result shows that the index proposed is capable of reflecting the profound effect of large-scaled EV loads on the transient voltage security of distribution network.","PeriodicalId":206418,"journal":{"name":"2014 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)","volume":"265 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115980612","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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