Pub Date : 2013-06-16DOI: 10.1109/ITEC.2013.6574514
Yue Zhao, W. Qiao, Long Wu
In this work, speed estimators are designed based on a model reference adaptive system (MRAS) for sensorless control of interior permanent magnet synchronous machines (IPMSMs). To provide better filtering performance and reduce the noise contents in the estimated speed, an adaptive line enhancer is proposed to work with a sliding-mode observer to provide an improved reference model for speed estimation. In addition, a heterodyning speed adaption scheme is proposed to replace the conventional speed adaption mechanism. The proposed MRAS-based speed estimator has two different operating modes, which are suitable for generator- and motor-type applications, respectively. The effectiveness of the proposed speed estimators are verified by simulation using real-word vehicle data logged from a test vehicle. Furthermore, experimental results on a test stand for a heavy-duty IPMSM are also provided.
{"title":"Model reference adaptive system-based speed estimators for sensorless control of interior permanent magnet synchronous machines","authors":"Yue Zhao, W. Qiao, Long Wu","doi":"10.1109/ITEC.2013.6574514","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6574514","url":null,"abstract":"In this work, speed estimators are designed based on a model reference adaptive system (MRAS) for sensorless control of interior permanent magnet synchronous machines (IPMSMs). To provide better filtering performance and reduce the noise contents in the estimated speed, an adaptive line enhancer is proposed to work with a sliding-mode observer to provide an improved reference model for speed estimation. In addition, a heterodyning speed adaption scheme is proposed to replace the conventional speed adaption mechanism. The proposed MRAS-based speed estimator has two different operating modes, which are suitable for generator- and motor-type applications, respectively. The effectiveness of the proposed speed estimators are verified by simulation using real-word vehicle data logged from a test vehicle. Furthermore, experimental results on a test stand for a heavy-duty IPMSM are also provided.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115723615","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6573499
W. Avelino, F. S. Garcia, A. A. Ferreira, J. Pomilio
An electric go-kart was designed and built. It uses a hybrid energy storage system composed of a battery and an ultracapacitor. To integrate the two energy storage devices, a multiple-input DC-DC converter was used to implement a control strategy that divides the power between them. The main objectives of using ultracapacitors in complement to batteries are: improving performance (i.e. acceleration), increase the system efficiency (including through the use of more regenerative braking) and extend the battery life. This paper presents the design of the electric go-kart and the experimental results obtained with the prototype.
{"title":"Electric go-kart with battery-ultracapacitor hybrid energy storage system","authors":"W. Avelino, F. S. Garcia, A. A. Ferreira, J. Pomilio","doi":"10.1109/ITEC.2013.6573499","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6573499","url":null,"abstract":"An electric go-kart was designed and built. It uses a hybrid energy storage system composed of a battery and an ultracapacitor. To integrate the two energy storage devices, a multiple-input DC-DC converter was used to implement a control strategy that divides the power between them. The main objectives of using ultracapacitors in complement to batteries are: improving performance (i.e. acceleration), increase the system efficiency (including through the use of more regenerative braking) and extend the battery life. This paper presents the design of the electric go-kart and the experimental results obtained with the prototype.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115208624","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6574517
N. Leboeuf, T. Boileau, B. Nahid-Mobarakeh, N. Takorabet, F. Meibody-Tabar, G. Clerc
In this paper, improved online inter-turn fault detection methods are proposed in order to take into account some design specifications related to recent Permanent Magnet Synchronous Machine (PMSM) topologies having modular stator combined with Fractionnal Slot Concentrated Winding (FSCW). This winding allows compact PM motor mainly by reducing end windings. It is often associated with segmented stator in order to simplify the construction of the motor as in the case of Electro-Mechanical Actuators (EMA). This technique may lead to the presence of manufacturing faults such as additional air gaps between the various parts of the modular stator. This urges users to consider complex models of PMSM far removed from classical dq models. Consequently, undesirable harmonics, torque ripples can interfere with fault detection such as inter-turn fault detection algorithms. This paper proposes invasive methods interacting with PMSM control using both model-based and data-based methods in order to take into account these aspects for control and online inter-turn fault detection. Various experimental tests on an industrial EMA prototype validate the effectiveness of the proposed solution.
{"title":"Hybrid data-based/model-based inter-turn fault detection methods for PM drives with manufacturing faults","authors":"N. Leboeuf, T. Boileau, B. Nahid-Mobarakeh, N. Takorabet, F. Meibody-Tabar, G. Clerc","doi":"10.1109/ITEC.2013.6574517","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6574517","url":null,"abstract":"In this paper, improved online inter-turn fault detection methods are proposed in order to take into account some design specifications related to recent Permanent Magnet Synchronous Machine (PMSM) topologies having modular stator combined with Fractionnal Slot Concentrated Winding (FSCW). This winding allows compact PM motor mainly by reducing end windings. It is often associated with segmented stator in order to simplify the construction of the motor as in the case of Electro-Mechanical Actuators (EMA). This technique may lead to the presence of manufacturing faults such as additional air gaps between the various parts of the modular stator. This urges users to consider complex models of PMSM far removed from classical dq models. Consequently, undesirable harmonics, torque ripples can interfere with fault detection such as inter-turn fault detection algorithms. This paper proposes invasive methods interacting with PMSM control using both model-based and data-based methods in order to take into account these aspects for control and online inter-turn fault detection. Various experimental tests on an industrial EMA prototype validate the effectiveness of the proposed solution.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129709139","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6573497
Andrea Caratti, Gabriele Catacchio, Carlo Gambino, N. Kar
The basic problem that this project addresses is the recovery of the kinetic energy lost during braking in a conventional vehicle. With Regenerative Braking Systems (RBS) it is possible to slow a vehicle down by converting its kinetic energy into electric energy, which can be either used immediately or stored until needed. This contrasts with conventional braking systems, where the excess kinetic energy is converted into heat by friction and wasted into the environment. In hybrid electric vehicles, the regenerative braking action is performed using the electric motor as a generator. In this way the energy from the wheels is converted from kinetic into electric and the magnetic friction between the rotor and the stator windings provides the braking effect. The aim of this study is to design a model of an electric system that allows converting the kinetic energy and storing it into a high voltage battery. The powertrain configurations investigated in this project are the mild and full hybrids, in which the internal combustion engine is coupled with an electric motor, able to provide a start/stop and a power assist functions in addition to the regenerative braking actions. The final result of the study is represented by a tool that has been implemented into Matlab® in order to predict the time variation of the electric quantities in a vehicle performing the New European Driving Cycle. This model also offers a predictive tool for dimensioning the main components of the system, according to the target electric parameters. Finally, the improvements that such a system could give in terms of efficiency, fuel consumption and emissions reduction have been analyzed. With respect to the existing models, this approach requires few main input parameters to characterize the RBS, resulting in a higher flexibility and a wider range of application.
{"title":"Development of a predictive model for Regenerative Braking System","authors":"Andrea Caratti, Gabriele Catacchio, Carlo Gambino, N. Kar","doi":"10.1109/ITEC.2013.6573497","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6573497","url":null,"abstract":"The basic problem that this project addresses is the recovery of the kinetic energy lost during braking in a conventional vehicle. With Regenerative Braking Systems (RBS) it is possible to slow a vehicle down by converting its kinetic energy into electric energy, which can be either used immediately or stored until needed. This contrasts with conventional braking systems, where the excess kinetic energy is converted into heat by friction and wasted into the environment. In hybrid electric vehicles, the regenerative braking action is performed using the electric motor as a generator. In this way the energy from the wheels is converted from kinetic into electric and the magnetic friction between the rotor and the stator windings provides the braking effect. The aim of this study is to design a model of an electric system that allows converting the kinetic energy and storing it into a high voltage battery. The powertrain configurations investigated in this project are the mild and full hybrids, in which the internal combustion engine is coupled with an electric motor, able to provide a start/stop and a power assist functions in addition to the regenerative braking actions. The final result of the study is represented by a tool that has been implemented into Matlab® in order to predict the time variation of the electric quantities in a vehicle performing the New European Driving Cycle. This model also offers a predictive tool for dimensioning the main components of the system, according to the target electric parameters. Finally, the improvements that such a system could give in terms of efficiency, fuel consumption and emissions reduction have been analyzed. With respect to the existing models, this approach requires few main input parameters to characterize the RBS, resulting in a higher flexibility and a wider range of application.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125942994","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6573484
A. Willwerth, M. Roman
With the increasing use of inverter-controlled traction motor systems in electric rail, road, and off-road vehicles, protecting motor bearings will become a key requirement for reliability. Partial mitigation measures against inverter-induced electrical bearing damage can merely shift the damage to gearbox bearings and create more maintenance headaches. In some vehicles, stray currents can also cause electromagnetic interference (EMI) and/or radio frequency interference (RFI) that can jeopardize electronic control systems. The best long-term solution is a contact/noncontact motor shaft grounding ring that works in the unique electric vehicle environment of high revolutions per minute (r/min), rapid acceleration, etc.
{"title":"Electrical bearing damage — A lurking problem in inverter-driven traction motors","authors":"A. Willwerth, M. Roman","doi":"10.1109/ITEC.2013.6573484","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6573484","url":null,"abstract":"With the increasing use of inverter-controlled traction motor systems in electric rail, road, and off-road vehicles, protecting motor bearings will become a key requirement for reliability. Partial mitigation measures against inverter-induced electrical bearing damage can merely shift the damage to gearbox bearings and create more maintenance headaches. In some vehicles, stray currents can also cause electromagnetic interference (EMI) and/or radio frequency interference (RFI) that can jeopardize electronic control systems. The best long-term solution is a contact/noncontact motor shaft grounding ring that works in the unique electric vehicle environment of high revolutions per minute (r/min), rapid acceleration, etc.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129333688","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6573470
Xiaomin Lu, K. Iyer, K. Mukherjee, N. Kar
Transit agencies are increasingly focused on making bus fleets cleaner, more efficient and cost effective by incorporating new clean propulsion technologies. Increased maintenance cost and lower lifetime of battery packs in existing hybrid electric buses have been major bottlenecks in motivating transit bus operators to rapidly switch to this energy efficient technology. Understanding the demerits of the current battery based energy storage technology and merits of the prospective flywheel based energy storage technology for transit bus application, this paper puts an effort to study the permanent magnet synchronous machine based flywheel energy storage system for the aforementioned application. A series transit hybrid bus with peaking vehicle control strategy has been taken into consideration with a macro objective to compare the performance of the battery based and flywheel based hybrid transit bus in terms of fuel consumption and cost of the installed system. However, the focus of this paper remains on the development and study of a 100 kW flywheel energy storage system based on vector control technique which forms the first step towards this macro objective.
{"title":"Study of permanent magnet machine based flywheel energy storage system for peaking power series hybrid vehicle control strategy","authors":"Xiaomin Lu, K. Iyer, K. Mukherjee, N. Kar","doi":"10.1109/ITEC.2013.6573470","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6573470","url":null,"abstract":"Transit agencies are increasingly focused on making bus fleets cleaner, more efficient and cost effective by incorporating new clean propulsion technologies. Increased maintenance cost and lower lifetime of battery packs in existing hybrid electric buses have been major bottlenecks in motivating transit bus operators to rapidly switch to this energy efficient technology. Understanding the demerits of the current battery based energy storage technology and merits of the prospective flywheel based energy storage technology for transit bus application, this paper puts an effort to study the permanent magnet synchronous machine based flywheel energy storage system for the aforementioned application. A series transit hybrid bus with peaking vehicle control strategy has been taken into consideration with a macro objective to compare the performance of the battery based and flywheel based hybrid transit bus in terms of fuel consumption and cost of the installed system. However, the focus of this paper remains on the development and study of a 100 kW flywheel energy storage system based on vector control technique which forms the first step towards this macro objective.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134177959","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6573486
Dusan Progovac, L. Wang, G. Yin
Permanent magnet machines are of high power density, high efficiency, small weight, and high reliability, and hence have found extensive applications. This paper employs system identification methods for stator winding fault detection and isolation, under noisy measurement data. Algorithms, estimation accuracy, and convergence properties are established. Simulation studies demonstrate the algorithms and their detection capability and reliability. Simulation results are used to illustrate potential usage of the methods.
{"title":"System identification of permanent magnet machines and its applications to inter-turn fault detection","authors":"Dusan Progovac, L. Wang, G. Yin","doi":"10.1109/ITEC.2013.6573486","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6573486","url":null,"abstract":"Permanent magnet machines are of high power density, high efficiency, small weight, and high reliability, and hence have found extensive applications. This paper employs system identification methods for stator winding fault detection and isolation, under noisy measurement data. Algorithms, estimation accuracy, and convergence properties are established. Simulation studies demonstrate the algorithms and their detection capability and reliability. Simulation results are used to illustrate potential usage of the methods.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124867256","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6573498
S. Faivre, A. Ravey, A. Djerdir, D. Bouquain
This paper presents a new approach concerning degraded conditions of energy converters in fuel cell hybrid electrical vehicles (FCHEVs) powertrain. After introducing weak points and systems of such powertrain and previous proposals boundaries, a solution, based on an adaptive power split control strategy is presented. This approach relies on energy and power sources state-of-health (SoH). SoH input is added to an existing fuzzy logic controller, in order to prevent an out-of-operation fault. Simulations results for different scenarios using real driving cycles are presented and discussed.
{"title":"Degraded control strategy using state-of-health in fuel cell hybrid electric vehicles","authors":"S. Faivre, A. Ravey, A. Djerdir, D. Bouquain","doi":"10.1109/ITEC.2013.6573498","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6573498","url":null,"abstract":"This paper presents a new approach concerning degraded conditions of energy converters in fuel cell hybrid electrical vehicles (FCHEVs) powertrain. After introducing weak points and systems of such powertrain and previous proposals boundaries, a solution, based on an adaptive power split control strategy is presented. This approach relies on energy and power sources state-of-health (SoH). SoH input is added to an existing fuzzy logic controller, in order to prevent an out-of-operation fault. Simulations results for different scenarios using real driving cycles are presented and discussed.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124299476","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6574500
Mahdi Kefayati, R. Baldick
Transportation is one of the major consumer of energy in US and around the world. According to the latest Department of Energy (DOE) Transportation Data Book [1], 27.8% of total US energy consumption is attributed to transportation. Of this amount, 58.9% is consumed by cars and light duty trucks to make up 16.4% of total energy consumed by Americans. To put this in perspective, according to DOE energy usage estimates [2] 39.2% of energy consumed in US is spent for electricity generation.
{"title":"PEV demand flexibility and its impact on the electric power system","authors":"Mahdi Kefayati, R. Baldick","doi":"10.1109/ITEC.2013.6574500","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6574500","url":null,"abstract":"Transportation is one of the major consumer of energy in US and around the world. According to the latest Department of Energy (DOE) Transportation Data Book [1], 27.8% of total US energy consumption is attributed to transportation. Of this amount, 58.9% is consumed by cars and light duty trucks to make up 16.4% of total energy consumed by Americans. To put this in perspective, according to DOE energy usage estimates [2] 39.2% of energy consumed in US is spent for electricity generation.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122509252","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 : 2013-06-16DOI: 10.1109/ITEC.2013.6574515
G. Su, P. Ning
This paper presents a study of loss modeling and comparison of a voltage source inverter (VSI) with a boost/buck converter and a current source inverter (CSI) with a V-I converter for electric vehicle (EV) traction drive applications. A comparison of the inverter losses for controlling an interior permanent magnet motor in an EV under two US EPA driving schedules is carried out. The results indicate the CSI using the currently available reverse-blocking (RB) IGBTs has lower losses for most of the vehicle operating points over the aggressive driving schedule, resulting in a reduction of 18.8 % in the accumulated energy loss at the end of the test cycle, while for the other less aggressive schedule a moderate reduction of 7.3 % is achieved.
{"title":"Loss modeling and comparison of VSI and RB-IGBT based CSI in traction drive applications","authors":"G. Su, P. Ning","doi":"10.1109/ITEC.2013.6574515","DOIUrl":"https://doi.org/10.1109/ITEC.2013.6574515","url":null,"abstract":"This paper presents a study of loss modeling and comparison of a voltage source inverter (VSI) with a boost/buck converter and a current source inverter (CSI) with a V-I converter for electric vehicle (EV) traction drive applications. A comparison of the inverter losses for controlling an interior permanent magnet motor in an EV under two US EPA driving schedules is carried out. The results indicate the CSI using the currently available reverse-blocking (RB) IGBTs has lower losses for most of the vehicle operating points over the aggressive driving schedule, resulting in a reduction of 18.8 % in the accumulated energy loss at the end of the test cycle, while for the other less aggressive schedule a moderate reduction of 7.3 % is achieved.","PeriodicalId":118616,"journal":{"name":"2013 IEEE Transportation Electrification Conference and Expo (ITEC)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122385962","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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