Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267966
M. Trapanese
In this paper a magnetic circuit model approach, which is able to describe hysteresis in electric machines, is presented. The method describes the ferromagnetic structure of an electric machine by a magnetic model circuit. Each part of the machine is described by permeances which can be linear or non linear, with hysteresis or not, in accordance with the material which this part is made of. The magnetic permeability needed to compute each permeance is described by Preisach's method. The presented model, based on Preisach's hysteresis scalar theory, allows to calculate not only the global hysteresis losses, but also the losses in each part of the machine as well as the distortion of the induced electromotive force (emf) and of the voltages. In order to verify this method, two cases have been examined: a) a transformer case; b) a switched reluctance drive. The first one has been experimentally tested the second one has been used to compare an alternative approach based on a FEM commercial package.
{"title":"Description of magnetic hysteresis effects in electrical drives by a circuit model approach","authors":"M. Trapanese","doi":"10.1109/ISIE.2003.1267966","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267966","url":null,"abstract":"In this paper a magnetic circuit model approach, which is able to describe hysteresis in electric machines, is presented. The method describes the ferromagnetic structure of an electric machine by a magnetic model circuit. Each part of the machine is described by permeances which can be linear or non linear, with hysteresis or not, in accordance with the material which this part is made of. The magnetic permeability needed to compute each permeance is described by Preisach's method. The presented model, based on Preisach's hysteresis scalar theory, allows to calculate not only the global hysteresis losses, but also the losses in each part of the machine as well as the distortion of the induced electromotive force (emf) and of the voltages. In order to verify this method, two cases have been examined: a) a transformer case; b) a switched reluctance drive. The first one has been experimentally tested the second one has been used to compare an alternative approach based on a FEM commercial package.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124592863","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267325
K. Veszprémi, I. Schmidt, M. Hunyár
The brushless excitation of synchronous machines is an attractive solution for wound rotor machines, since no slip rings are necessary. The paper investigates the rotating transformer method, where the excitation machine is a wound rotor induction machine supplied by an excitation converter. A diode bridge rectifier connected to the three-phase rotor of the excitation machine excites the synchronous machine. The possible power circuits for the excitation converter are presented and the PWM AC chopper is proposed, providing almost sinusoidal supply for the excitation machine. The operation of the system is essentially determined by the commutation of the rotating diode bridge. The different working regions of the diode bridge are considered. The characteristics of the steady-state operation considering the utilization of the excitation machine are introduced, providing a complex design method for the system. A simple and easy feasible method is given for the indirect sensing of the excitation current.
{"title":"Optimal operation of the rotating transformer brushless excitation of synchronous machine","authors":"K. Veszprémi, I. Schmidt, M. Hunyár","doi":"10.1109/ISIE.2003.1267325","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267325","url":null,"abstract":"The brushless excitation of synchronous machines is an attractive solution for wound rotor machines, since no slip rings are necessary. The paper investigates the rotating transformer method, where the excitation machine is a wound rotor induction machine supplied by an excitation converter. A diode bridge rectifier connected to the three-phase rotor of the excitation machine excites the synchronous machine. The possible power circuits for the excitation converter are presented and the PWM AC chopper is proposed, providing almost sinusoidal supply for the excitation machine. The operation of the system is essentially determined by the commutation of the rotating diode bridge. The different working regions of the diode bridge are considered. The characteristics of the steady-state operation considering the utilization of the excitation machine are introduced, providing a complex design method for the system. A simple and easy feasible method is given for the indirect sensing of the excitation current.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124694900","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267250
X. Dianguo, Zhao Kaiqi, W. Yi
The voltage across three-phase non-conducting thyristor is used to obtain information of the motor operation. The voltage amplitude is an indication of motor speed, while the phase angle of the voltage across it is an index of power factor angle. Thus a novel method for the speed detection in three-phase induction motors without additional speed sensors is presented. This method utilizes the characteristics of the thyristor voltage controller and the motor running state under the asymmetric power supply to find the relationship between the induction voltage of the one phase of the motor without power supply and the motor speed, hence the relationship between the RMS voltage across the non-conducting thyristor and the motor speed. In addition, an analysis of the rule of power factor angle vs. speed in the three-phase induction motor is presented. Through analyzing the cause of phase current oscillation during soft starting, the power factor angle closed-loop control is introduced to induction motor soft starters. It is pointed out that the thyristor firing angle is composed of two parts. One is obtained from the pre-determined voltage control rule, and the other is the increment of dynamic regulating angle with the variation of power factor angle. Experimental results show that the proposed closed-loop control method can avoid current oscillation during soft starting.
{"title":"Novel method of speed direction and power factor control in thyristor controlled induction motor","authors":"X. Dianguo, Zhao Kaiqi, W. Yi","doi":"10.1109/ISIE.2003.1267250","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267250","url":null,"abstract":"The voltage across three-phase non-conducting thyristor is used to obtain information of the motor operation. The voltage amplitude is an indication of motor speed, while the phase angle of the voltage across it is an index of power factor angle. Thus a novel method for the speed detection in three-phase induction motors without additional speed sensors is presented. This method utilizes the characteristics of the thyristor voltage controller and the motor running state under the asymmetric power supply to find the relationship between the induction voltage of the one phase of the motor without power supply and the motor speed, hence the relationship between the RMS voltage across the non-conducting thyristor and the motor speed. In addition, an analysis of the rule of power factor angle vs. speed in the three-phase induction motor is presented. Through analyzing the cause of phase current oscillation during soft starting, the power factor angle closed-loop control is introduced to induction motor soft starters. It is pointed out that the thyristor firing angle is composed of two parts. One is obtained from the pre-determined voltage control rule, and the other is the increment of dynamic regulating angle with the variation of power factor angle. Experimental results show that the proposed closed-loop control method can avoid current oscillation during soft starting.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128240835","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267941
D. Pan, H.W. Li, B. Wilamowski
Phase-locked loops (PLLs) are often used as frequency multiplier for generating high frequency clock signals. In space application, however, performance of the normal PLL is degraded due to the radiation effects. In this paper, several aspects of a rad-hard PLL are investigated, including radiation effects, radiation hardening techniques, PLL building blocks and the overall performance. This circuit is developed using the Peregrine 0.50 /spl mu/m SOS/SOI process. The post-layout simulation result indicates that the circuit can be used to generate 100 M - I80 MHz programmable clock signal under radiation conditions with process, temperature and voltage variations. The maximum peak to peak jitter is less than 100 ps while the maximum lock-in time is less than 20 us under typical conditions.
{"title":"A radiation-hard phase-locked loop","authors":"D. Pan, H.W. Li, B. Wilamowski","doi":"10.1109/ISIE.2003.1267941","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267941","url":null,"abstract":"Phase-locked loops (PLLs) are often used as frequency multiplier for generating high frequency clock signals. In space application, however, performance of the normal PLL is degraded due to the radiation effects. In this paper, several aspects of a rad-hard PLL are investigated, including radiation effects, radiation hardening techniques, PLL building blocks and the overall performance. This circuit is developed using the Peregrine 0.50 /spl mu/m SOS/SOI process. The post-layout simulation result indicates that the circuit can be used to generate 100 M - I80 MHz programmable clock signal under radiation conditions with process, temperature and voltage variations. The maximum peak to peak jitter is less than 100 ps while the maximum lock-in time is less than 20 us under typical conditions.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130682203","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267317
J. Fariña, O. Fernandez-Pol, J. Rodríguez-Andina, J. Bullón, A. Lorenzo
This paper presents the latest developments in the characterization of the response of submerged arc furnaces used in silicon production facilities worldwide. Such characterization is needed to allow an efficient on-line monitoring of the furnace to be carried out. As demonstrated in previous works, the monitoring process is useful not only to check the operation, but also to determine the values of some important parameters of the furnace. The paper describes the way in which a microcontroller-based monitoring system is being used to determine the frequency response of the electrodes in the furnaces of the silicon production facility of the company Ferroatlantica, in Spain. Experimental results are presented and discussed.
{"title":"Characterization of the frequency response of electrodes in arc furnaces for silicon production","authors":"J. Fariña, O. Fernandez-Pol, J. Rodríguez-Andina, J. Bullón, A. Lorenzo","doi":"10.1109/ISIE.2003.1267317","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267317","url":null,"abstract":"This paper presents the latest developments in the characterization of the response of submerged arc furnaces used in silicon production facilities worldwide. Such characterization is needed to allow an efficient on-line monitoring of the furnace to be carried out. As demonstrated in previous works, the monitoring process is useful not only to check the operation, but also to determine the values of some important parameters of the furnace. The paper describes the way in which a microcontroller-based monitoring system is being used to determine the frequency response of the electrodes in the furnaces of the silicon production facility of the company Ferroatlantica, in Spain. Experimental results are presented and discussed.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132279603","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267298
T. Yamazaki
Multimedia applications that treat various types of data like videos, audios, and images are becoming popular amongst the Internet users. Assuming best-effort networks as the infrastructure, we are developing a multimedia data retrieval system based on QoS (quality of service) concept that searches and retrieves various types of multimedia data from plural multimedia data archives. As one of QoS parameters, we select the user's response time. Since the response time is related with network throughputs, throughput measurement becomes an important technology in the system. So far, we have developed a mechanism to decide a retrieval order of multimedia data that match with the user's searching request. The mechanism is called QoS scenario and it balances the user's searching request (keyword matching) and the QoS factor related with the user's response time that can be determined by the throughput measurement. The QoS scenario was used in the first version of our multimedia data retrieval system. In this paper, we study the active and passive throughput measurement technologies. Also, a multimedia data structure is introduced on the basis of the Dublin Core that has been standardized. Owing to the multimedia data structure, the system is able to hold interoperability and wide-area-network search and retrieval can be realized.
{"title":"A study of QoS-based multimedia data retrieval systems","authors":"T. Yamazaki","doi":"10.1109/ISIE.2003.1267298","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267298","url":null,"abstract":"Multimedia applications that treat various types of data like videos, audios, and images are becoming popular amongst the Internet users. Assuming best-effort networks as the infrastructure, we are developing a multimedia data retrieval system based on QoS (quality of service) concept that searches and retrieves various types of multimedia data from plural multimedia data archives. As one of QoS parameters, we select the user's response time. Since the response time is related with network throughputs, throughput measurement becomes an important technology in the system. So far, we have developed a mechanism to decide a retrieval order of multimedia data that match with the user's searching request. The mechanism is called QoS scenario and it balances the user's searching request (keyword matching) and the QoS factor related with the user's response time that can be determined by the throughput measurement. The QoS scenario was used in the first version of our multimedia data retrieval system. In this paper, we study the active and passive throughput measurement technologies. Also, a multimedia data structure is introduced on the basis of the Dublin Core that has been standardized. Owing to the multimedia data structure, the system is able to hold interoperability and wide-area-network search and retrieval can be realized.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128781507","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267935
F. Y. Nakamoto, P. E. Miyagi, D. J. Dos Santos Filho
The flexible production systems (FPSs) execute multiple processes simultaneously using the same set of resources. These processes can be blocked permanently due to lack of information about sequence of the activities of the processes; i.e. the processes sharing a finite set of resources may eventually freeze or the system comes in the deadlock state. Another aspect is about the dynamic behavior of FPSs. The FPSs belong to the class of discrete event systems (DESs); therefore, the dynamic behavior is based on the occurrence of events. In this context, it is not possible to determine when an event occurs and the sequence of events becomes indefinite. Such systems can be classified as complex production systems and these systems can be modeled using Petri net. This work adopts a method that boards the deadlock problem considering the complexity of FPSs. The goal of this work is to introduce the systematization of the method, in other words, introduce an algorithmic approach. This approach allows the implementation of a computational tools which, given some information about FPSs, generates automatically the algorithm of control of resources utilization and the control rules with the goal of avoiding the deadlock.
{"title":"Systematization of the project of the production system control","authors":"F. Y. Nakamoto, P. E. Miyagi, D. J. Dos Santos Filho","doi":"10.1109/ISIE.2003.1267935","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267935","url":null,"abstract":"The flexible production systems (FPSs) execute multiple processes simultaneously using the same set of resources. These processes can be blocked permanently due to lack of information about sequence of the activities of the processes; i.e. the processes sharing a finite set of resources may eventually freeze or the system comes in the deadlock state. Another aspect is about the dynamic behavior of FPSs. The FPSs belong to the class of discrete event systems (DESs); therefore, the dynamic behavior is based on the occurrence of events. In this context, it is not possible to determine when an event occurs and the sequence of events becomes indefinite. Such systems can be classified as complex production systems and these systems can be modeled using Petri net. This work adopts a method that boards the deadlock problem considering the complexity of FPSs. The goal of this work is to introduce the systematization of the method, in other words, introduce an algorithmic approach. This approach allows the implementation of a computational tools which, given some information about FPSs, generates automatically the algorithm of control of resources utilization and the control rules with the goal of avoiding the deadlock.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"53 52","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113936504","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267914
A. S. Morais, J. Vilela, J. Vieira, L. D. de Freitas, V. J. Farias
A new converter is proposed with a power factor control and a resonant auxiliary capacitive branch to provide reduction of current in a switch and also to provide soft commutation in another switch.
{"title":"Boost half-bridge ballast with high power factor and auxiliary resonant branch","authors":"A. S. Morais, J. Vilela, J. Vieira, L. D. de Freitas, V. J. Farias","doi":"10.1109/ISIE.2003.1267914","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267914","url":null,"abstract":"A new converter is proposed with a power factor control and a resonant auxiliary capacitive branch to provide reduction of current in a switch and also to provide soft commutation in another switch.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"486 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114281078","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267920
A. Dell'Aquila, A. Lecci, Marco Liserre
The half-bridge converter can be successfully employed as an active filter in single-phase systems. The impact of this configuration becomes particularly relevant if the power level is limited and the cost reduction becomes a key point. In fact the half-bridge is made by only two bi-directional switches and two capacitors, being anyway able to ensure proper compensation even of the low order harmonics generated by a diode bridge. In this paper, the problem of the balancing of the voltages of the two capacitors is investigated, aiming to do not use a separate controller but only a simple combination logic that exploits the redundancies of the configuration. The simulation and the experimental results show that the voltages can not be controlled in all the conditions but this lack of performance does not affect very much the behavior of the active filter; the compensation of the selected harmonic currents is still good.
{"title":"A technique to balance a half-bridge single-phase active filter","authors":"A. Dell'Aquila, A. Lecci, Marco Liserre","doi":"10.1109/ISIE.2003.1267920","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267920","url":null,"abstract":"The half-bridge converter can be successfully employed as an active filter in single-phase systems. The impact of this configuration becomes particularly relevant if the power level is limited and the cost reduction becomes a key point. In fact the half-bridge is made by only two bi-directional switches and two capacitors, being anyway able to ensure proper compensation even of the low order harmonics generated by a diode bridge. In this paper, the problem of the balancing of the voltages of the two capacitors is investigated, aiming to do not use a separate controller but only a simple combination logic that exploits the redundancies of the configuration. The simulation and the experimental results show that the voltages can not be controlled in all the conditions but this lack of performance does not affect very much the behavior of the active filter; the compensation of the selected harmonic currents is still good.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122497158","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 : 2003-06-09DOI: 10.1109/ISIE.2003.1267973
M. Rodrigues, H. Braga
This work describes the experimental validation of a mathematical modeling of a single-phase PWM active power filter, previously proposed. This model has been developed using the PWM switch technique, created by Vorperian. Laboratorial tests have been developed to verify the validity of several proposed relationships like static gain, line-to-output and control-to-output transfer functions, using tests like step response and frequency response. Due to the narrow agreement between experimental and simulated results, the authors believe the functions developed can be widely employed to describe the system behavior, as well they can be used as support to various control strategies propositions.
{"title":"Experimental validation of a mathematical modeling of single-phase active power filter","authors":"M. Rodrigues, H. Braga","doi":"10.1109/ISIE.2003.1267973","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267973","url":null,"abstract":"This work describes the experimental validation of a mathematical modeling of a single-phase PWM active power filter, previously proposed. This model has been developed using the PWM switch technique, created by Vorperian. Laboratorial tests have been developed to verify the validity of several proposed relationships like static gain, line-to-output and control-to-output transfer functions, using tests like step response and frequency response. Due to the narrow agreement between experimental and simulated results, the authors believe the functions developed can be widely employed to describe the system behavior, as well they can be used as support to various control strategies propositions.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131413937","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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