Pub Date : 2007-12-26DOI: 10.1109/IREP.2007.4410542
S. Bose, Y. Liu, K. Bahei-Eldin, J. de Bedout, M. Adamiak
This paper reviews the overall architecture of the Microgrid concept, and presents details associated with the tieline control features. Laboratory results from exercising the tieline controls in a hardware-in-the-loop environment are also presented. The controls are implemented with Matlab/Simulink software running on a PC, using data provided from a digital relay through the IEC 61850 GOOSE/OPC data transfer mechanism.
{"title":"Tieline controls in microgrid applications","authors":"S. Bose, Y. Liu, K. Bahei-Eldin, J. de Bedout, M. Adamiak","doi":"10.1109/IREP.2007.4410542","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410542","url":null,"abstract":"This paper reviews the overall architecture of the Microgrid concept, and presents details associated with the tieline control features. Laboratory results from exercising the tieline controls in a hardware-in-the-loop environment are also presented. The controls are implemented with Matlab/Simulink software running on a PC, using data provided from a digital relay through the IEC 61850 GOOSE/OPC data transfer mechanism.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121402888","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410550
W. Qiao, R. Harley, G. Venayagamoorthy
Flexible AC transmission system (FACTS) devices are widely recognized as powerful controllers to improve the dynamic performance and stability of power systems. The standard FACTS controllers are linear controllers designed around a specific operating point from a linearized system model with fixed parameters. However, at other operating points their performance degrades. Neural-network-based nonlinear intelligent control offers an attractive approach to overcome the drawbacks of the linear controllers. This paper presents two different neural-network-based intelligent control architectures, i.e., indirect adaptive neurocontrol and adaptive critic design based optimal neurocontrol, for designing the external control of an SSSC FACTS device. Simulation studies are carried out to evaluate the proposed nonlinear intelligent controllers on single machine infinite bus as well as multi-machine power systems. Results show that the proposed intelligent controls improve the dynamic performance of the SSSC and the associated power network.
{"title":"Neural-network-based intelligent control for improving dynamic performance of FACTS devices","authors":"W. Qiao, R. Harley, G. Venayagamoorthy","doi":"10.1109/IREP.2007.4410550","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410550","url":null,"abstract":"Flexible AC transmission system (FACTS) devices are widely recognized as powerful controllers to improve the dynamic performance and stability of power systems. The standard FACTS controllers are linear controllers designed around a specific operating point from a linearized system model with fixed parameters. However, at other operating points their performance degrades. Neural-network-based nonlinear intelligent control offers an attractive approach to overcome the drawbacks of the linear controllers. This paper presents two different neural-network-based intelligent control architectures, i.e., indirect adaptive neurocontrol and adaptive critic design based optimal neurocontrol, for designing the external control of an SSSC FACTS device. Simulation studies are carried out to evaluate the proposed nonlinear intelligent controllers on single machine infinite bus as well as multi-machine power systems. Results show that the proposed intelligent controls improve the dynamic performance of the SSSC and the associated power network.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132740097","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410527
C. Genesi, G. Granelli, P. Marannino, M. Montagna, F. Zanellini
Based on the analysis of the recent huge blackouts that stroke some countries in the European systems, the authors of the paper emphasize as a right knowledge of the actual cross border transmission capacities (CBTCs) is becoming of primary importance in order to obtain a secure operation of the whole system, independently from the method adopted in its allocation. Among the different methods proposed for the CBTCs allocation the behavior of the so called coordinated auctioning (CA) has been simulated in an automatic procedure applied to the analysis of the UCTE system with reference to scenarios of the years 2005 and 2010. The adopted simulator allows the supervision of the network flows not only in each interconnection line, but also in the first ones living the borders to enter in the national networks. Opening a larger window on the network flows, the simulator is able to put in evidence the role played in the CBTC allocation by the presence of internal bottlenecks. Examples are given showing as limiting the control to the Net Transmission Capacity (NTC) published by each Transmission System Operator (TSO) or extending the supervision only to the lines of the interconnection corridors is not enough to attain the most suitable information for a secure and economic CBTC allocation.
{"title":"Opening a larger window on network flows to enhance the cross border capacity allocation in bulk interconnected systems","authors":"C. Genesi, G. Granelli, P. Marannino, M. Montagna, F. Zanellini","doi":"10.1109/IREP.2007.4410527","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410527","url":null,"abstract":"Based on the analysis of the recent huge blackouts that stroke some countries in the European systems, the authors of the paper emphasize as a right knowledge of the actual cross border transmission capacities (CBTCs) is becoming of primary importance in order to obtain a secure operation of the whole system, independently from the method adopted in its allocation. Among the different methods proposed for the CBTCs allocation the behavior of the so called coordinated auctioning (CA) has been simulated in an automatic procedure applied to the analysis of the UCTE system with reference to scenarios of the years 2005 and 2010. The adopted simulator allows the supervision of the network flows not only in each interconnection line, but also in the first ones living the borders to enter in the national networks. Opening a larger window on the network flows, the simulator is able to put in evidence the role played in the CBTC allocation by the presence of internal bottlenecks. Examples are given showing as limiting the control to the Net Transmission Capacity (NTC) published by each Transmission System Operator (TSO) or extending the supervision only to the lines of the interconnection corridors is not enough to attain the most suitable information for a secure and economic CBTC allocation.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115672514","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410559
V. Madani, W. Higinbotham
This paper explains the challenges and addresses the benefits associated with utilizing products that provide multiple communications paths. Methods for employing IP networks for real time information collection will be discussed. Communications schemes are presented with traditional media including audio, digital, fiber, and IP networks. Examples of how analog data, status points, and HMI information can be transported on these networks are also described. The technology also simplifies connectivity, reduces hardware and potential failures, and offers a variety of diagnostics monitoring both at the equipment level as well as the system level. New methods will be shown that can decrease the communication's systems complexities even further to lower costs, improve system performance, and increase overall system reliability and MTBF.
{"title":"Advantages in modern communications as applied to Remedial Action Schemes and control centers","authors":"V. Madani, W. Higinbotham","doi":"10.1109/IREP.2007.4410559","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410559","url":null,"abstract":"This paper explains the challenges and addresses the benefits associated with utilizing products that provide multiple communications paths. Methods for employing IP networks for real time information collection will be discussed. Communications schemes are presented with traditional media including audio, digital, fiber, and IP networks. Examples of how analog data, status points, and HMI information can be transported on these networks are also described. The technology also simplifies connectivity, reduces hardware and potential failures, and offers a variety of diagnostics monitoring both at the equipment level as well as the system level. New methods will be shown that can decrease the communication's systems complexities even further to lower costs, improve system performance, and increase overall system reliability and MTBF.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128511817","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410567
Qian Chen, P. Ju, Z. Shao, Feng Wu
In order to consider the effect of the distribution network on the load modeling, a synthesis load model (SLM) including the power load and the distribution network has been proposed. Using SLM, the accuracy of the load modeling can be improved. At the same time, a strategy of the parameter estimation of the SLM is proposed in this paper. The proposed parameter estimation strategy is based on the combination of the component based and the measurement based load modeling method. During parameter estimation, only the parameters playing very important roles in the dynamics of the composite load model are estimated, while the other parameters playing limited role are set as the default values which is obtained by the component based method. The efficiency of the proposed strategy is verified by the load modeling based on the field measurements.
{"title":"Electrical load modeling with considering distribution network","authors":"Qian Chen, P. Ju, Z. Shao, Feng Wu","doi":"10.1109/IREP.2007.4410567","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410567","url":null,"abstract":"In order to consider the effect of the distribution network on the load modeling, a synthesis load model (SLM) including the power load and the distribution network has been proposed. Using SLM, the accuracy of the load modeling can be improved. At the same time, a strategy of the parameter estimation of the SLM is proposed in this paper. The proposed parameter estimation strategy is based on the combination of the component based and the measurement based load modeling method. During parameter estimation, only the parameters playing very important roles in the dynamics of the composite load model are estimated, while the other parameters playing limited role are set as the default values which is obtained by the component based method. The efficiency of the proposed strategy is verified by the load modeling based on the field measurements.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127136054","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410569
A. Tiwari, V. Ajjarapu
This paper proposes a novel approach for contingency filtering, ranking and assessment for contingencies that cause power quality and voltage instability problems. The approach consists of two-block technique: the first block filters out dangerous contingencies from a list of credible contingencies; then second block ranks and assesses them. Apart from ranking contingencies in order of their severity (CSI); a new concept of finding dynamic bus voltage vulnerability index (DBVVI) is proposed and is used to rank buses in order of their vulnerability. This filtering, ranking and assessment (FRA) approach uses decoupled time domain method for analysis. Decouple time-domain method is a good blend of accuracy and computational efficiency. The proposed FRA approach is totally generic; it can adapt itself to any specifics of power system (i.e. modeling, protection), any contingency scenario (i.e. N-1, N-2), and for any type of application (planning, operation). The approach is illustrated on IEEE 39 Bus system. The capability of filtering and ranking methodology is illustrated by its performance criteria: reliability, effectiveness and computational efficiency. Finally, the information obtained from filtering and ranking is used for assessment to provide planner/operator with sound information to aid them in deciding an effective control strategy to make power system more robust.
{"title":"Contingency assessment for voltage dip and short term voltage stability analysis","authors":"A. Tiwari, V. Ajjarapu","doi":"10.1109/IREP.2007.4410569","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410569","url":null,"abstract":"This paper proposes a novel approach for contingency filtering, ranking and assessment for contingencies that cause power quality and voltage instability problems. The approach consists of two-block technique: the first block filters out dangerous contingencies from a list of credible contingencies; then second block ranks and assesses them. Apart from ranking contingencies in order of their severity (CSI); a new concept of finding dynamic bus voltage vulnerability index (DBVVI) is proposed and is used to rank buses in order of their vulnerability. This filtering, ranking and assessment (FRA) approach uses decoupled time domain method for analysis. Decouple time-domain method is a good blend of accuracy and computational efficiency. The proposed FRA approach is totally generic; it can adapt itself to any specifics of power system (i.e. modeling, protection), any contingency scenario (i.e. N-1, N-2), and for any type of application (planning, operation). The approach is illustrated on IEEE 39 Bus system. The capability of filtering and ranking methodology is illustrated by its performance criteria: reliability, effectiveness and computational efficiency. Finally, the information obtained from filtering and ranking is used for assessment to provide planner/operator with sound information to aid them in deciding an effective control strategy to make power system more robust.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124572800","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410548
Guoping Liu, J. Quintero, V. Venkatasubramanian
With the growing implementation of synchrophasors or PMU's across the power grid, it is now possible to observe and analyze system wide dynamic phenomena in real-time. This paper presents the framework of an automatic real-time oscillation monitoring expert system for extracting the modal information and mode shape of electromagnetic oscillations while they are still emerging in the real power system. The algorithms use three signal processing engines, namely, Prony's method, matrix pencil method and Hankel total least squares (HTLS) method. Results from these engines are processed using a custom developed set of rules for handling the complexities of modal analysis from real-time PMU measurements. The results are illustrated on several actual PMU recordings from power systems in North America. A simple powerful control design is also explored to initiate a supplementary HVDC modulation scheme to damp out inter-area oscillations when the oscillation monitoring system detects poorly damped oscillations.
{"title":"Oscillation monitoring system based on wide area synchrophasors in power systems","authors":"Guoping Liu, J. Quintero, V. Venkatasubramanian","doi":"10.1109/IREP.2007.4410548","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410548","url":null,"abstract":"With the growing implementation of synchrophasors or PMU's across the power grid, it is now possible to observe and analyze system wide dynamic phenomena in real-time. This paper presents the framework of an automatic real-time oscillation monitoring expert system for extracting the modal information and mode shape of electromagnetic oscillations while they are still emerging in the real power system. The algorithms use three signal processing engines, namely, Prony's method, matrix pencil method and Hankel total least squares (HTLS) method. Results from these engines are processed using a custom developed set of rules for handling the complexities of modal analysis from real-time PMU measurements. The results are illustrated on several actual PMU recordings from power systems in North America. A simple powerful control design is also explored to initiate a supplementary HVDC modulation scheme to damp out inter-area oscillations when the oscillation monitoring system detects poorly damped oscillations.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124679304","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410530
Antonio Simões Costa, R. Salgado, Paulo Haas
This paper proposes the combination of trust region methods and sequential-orthogonal techniques in order to devise globally convergent state estimators. The general nonlinear least squares problem in the context of power system state estimation is formulated so as to include inequality constraints which model the trust region. It is shown that the required changes on the state estimation equations solved in each iteration are equivalent to considering the contribution of properly defined a priori state information to the estimation process. Since a priori information are easily taken into account by the three-multiplier version of Givens rotations, the latter are employed to solve the linearized problem. This imparts numerical robustness to the iterative process in addition to the algorithmic robustness of the trust region approach, thereby improving the state estimator capability to converge even in the presence of severe modeling errors.
{"title":"Globally convergent state estimation based on givens rotations","authors":"Antonio Simões Costa, R. Salgado, Paulo Haas","doi":"10.1109/IREP.2007.4410530","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410530","url":null,"abstract":"This paper proposes the combination of trust region methods and sequential-orthogonal techniques in order to devise globally convergent state estimators. The general nonlinear least squares problem in the context of power system state estimation is formulated so as to include inequality constraints which model the trust region. It is shown that the required changes on the state estimation equations solved in each iteration are equivalent to considering the contribution of properly defined a priori state information to the estimation process. Since a priori information are easily taken into account by the three-multiplier version of Givens rotations, the latter are employed to solve the linearized problem. This imparts numerical robustness to the iterative process in addition to the algorithmic robustness of the trust region approach, thereby improving the state estimator capability to converge even in the presence of severe modeling errors.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132007749","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410566
K.A. Fahid, P. Gopalakrishnan, S. Cherian
Phasor measure unit (PMU) deployment for wide area monitoring systems (WAMS) results in large amount's of data being generated every second across the PMU network, the intermediate data concentrator's and the central monitoring center. This large amount of data evacuation provides practical bottlenecks with the prevalent network architecture and communication schemes. This paper looks at this problem; by studying the underlying reason's for communication bottlenecks and proposes an enhanced architecture to address this issue.
{"title":"PhasorNet A High Performance Network Communications Architecture for Synchrophasor Data Transfer in Wide Area Monitoring, Protection and Control Applications","authors":"K.A. Fahid, P. Gopalakrishnan, S. Cherian","doi":"10.1109/IREP.2007.4410566","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410566","url":null,"abstract":"Phasor measure unit (PMU) deployment for wide area monitoring systems (WAMS) results in large amount's of data being generated every second across the PMU network, the intermediate data concentrator's and the central monitoring center. This large amount of data evacuation provides practical bottlenecks with the prevalent network architecture and communication schemes. This paper looks at this problem; by studying the underlying reason's for communication bottlenecks and proposes an enhanced architecture to address this issue.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117169629","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 : 2007-12-26DOI: 10.1109/IREP.2007.4410511
H. Latorre, M. Ghandhari, L. Soder
Multichoice control strategy -MCS-consists in the selection of the correct input signals that will allow the VSC-HVDC to enhance the transient stability of the system, increase the level of damping, provide voltage support at specific nodes or change the power flow in the system, as it is required by the system when disturbances occur or ordered by the operator. This paper gives a description of the MCS and presents the procedure followed in the calculation of POD signals and a comparison of those signals with the signal derived from Lyapunov theory (Control Lya-punov Function -CLF-). All the signals were used in both small and large disturbances. The formulation of the MCS is based on a synchronous connection of the VSC-HVDC.
{"title":"Multichoice Control Strategy for VSC-HVdc","authors":"H. Latorre, M. Ghandhari, L. Soder","doi":"10.1109/IREP.2007.4410511","DOIUrl":"https://doi.org/10.1109/IREP.2007.4410511","url":null,"abstract":"Multichoice control strategy -MCS-consists in the selection of the correct input signals that will allow the VSC-HVDC to enhance the transient stability of the system, increase the level of damping, provide voltage support at specific nodes or change the power flow in the system, as it is required by the system when disturbances occur or ordered by the operator. This paper gives a description of the MCS and presents the procedure followed in the calculation of POD signals and a comparison of those signals with the signal derived from Lyapunov theory (Control Lya-punov Function -CLF-). All the signals were used in both small and large disturbances. The formulation of the MCS is based on a synchronous connection of the VSC-HVDC.","PeriodicalId":214545,"journal":{"name":"2007 iREP Symposium - Bulk Power System Dynamics and Control - VII. Revitalizing Operational Reliability","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116653606","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：