Pub Date : 2009-05-08DOI: 10.1109/ISPLC.2009.4913399
A. Mengi, A. H. Han Vinck
Orthogonal frequency division multiplexing (OFDM) with a small number of subcarriers (≤ 64) is shown to be promising in the narrowband power line communication (PLC) when the peak-to-average power ratio is reduced to the CENELEC standards. Although many authors studied the performance of the OFDM systems under the impulsive noise, their considerations are mostly restricted to OFDM systems with a large number of subcarriers. In that case, discrete Fourier transform (DFT) spreads the impulsive noise in such a way that its distribution in the frequency domain can be approximated as Gaussian. If the number of subcarriers is small, these methods can be hardly used. We describe an iterative algorithm for correcting the impulsive noise erors for the OFDM transmission with a small number of subcarriers. Simulation results for a 16-OFDM-QPSK systems show that the influence of impulive noise can be essentially reduced.
{"title":"Impulsive noise error correction in 16-OFDM for narrowband power line communication","authors":"A. Mengi, A. H. Han Vinck","doi":"10.1109/ISPLC.2009.4913399","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913399","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) with a small number of subcarriers (≤ 64) is shown to be promising in the narrowband power line communication (PLC) when the peak-to-average power ratio is reduced to the CENELEC standards. Although many authors studied the performance of the OFDM systems under the impulsive noise, their considerations are mostly restricted to OFDM systems with a large number of subcarriers. In that case, discrete Fourier transform (DFT) spreads the impulsive noise in such a way that its distribution in the frequency domain can be approximated as Gaussian. If the number of subcarriers is small, these methods can be hardly used. We describe an iterative algorithm for correcting the impulsive noise erors for the OFDM transmission with a small number of subcarriers. Simulation results for a 16-OFDM-QPSK systems show that the influence of impulive noise can be essentially reduced.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"02 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128556096","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913425
S. D'Alessandro, A. Tonello, L. Lampe
The achievable rate of OFDM systems is not necessarily maximized when deploying a cyclic prefix (CP) as long as the channel impulse response. Even though for shorter CP lengths both inter-symbol and inter-carrier interference do occur, the rate gain offered by a shortened CP may exceed the losses due to interference. In this paper we address the problem of CP length adaptation and we propose practical bit-loading algorithms that include the CP adaptation.
{"title":"Bit-loading algorithms for OFDM with adaptive cyclic prefix length in PLC channels","authors":"S. D'Alessandro, A. Tonello, L. Lampe","doi":"10.1109/ISPLC.2009.4913425","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913425","url":null,"abstract":"The achievable rate of OFDM systems is not necessarily maximized when deploying a cyclic prefix (CP) as long as the channel impulse response. Even though for shorter CP lengths both inter-symbol and inter-carrier interference do occur, the rate gain offered by a shortened CP may exceed the losses due to interference. In this paper we address the problem of CP length adaptation and we propose practical bit-loading algorithms that include the CP adaptation.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124625746","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913444
M. Ouzzif, J. Le Masson
This paper aims at presenting the impact of the Cyclic Prefix (CP) length on the maximal achievable throughput for multicarrier modulations used in Power Line Communications (PLC). The maximal throughputs including the interference caused by a channel impulse response length exceeding the cyclic prefix length are calculated and compared to simulation results. The statistical distribution of the optimal cyclic prefix length is conducted using channel measurements that were carried out by Orange Labs in different residential sites. Statistical analysis helps determine the best CP lengths configurations that approach the optimal achievable throughputs.
{"title":"Statistical analysis of the Cyclic Prefix impact on indoor PLC capacity","authors":"M. Ouzzif, J. Le Masson","doi":"10.1109/ISPLC.2009.4913444","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913444","url":null,"abstract":"This paper aims at presenting the impact of the Cyclic Prefix (CP) length on the maximal achievable throughput for multicarrier modulations used in Power Line Communications (PLC). The maximal throughputs including the interference caused by a channel impulse response length exceeding the cyclic prefix length are calculated and compared to simulation results. The statistical distribution of the optimal cyclic prefix length is conducted using channel measurements that were carried out by Orange Labs in different residential sites. Statistical analysis helps determine the best CP lengths configurations that approach the optimal achievable throughputs.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126820933","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913446
R. Riva, Marco Odoni, E. Guerrini, P. Bisaglia
In this paper we investigate channel estimation in the context of the OFDM-based HomePlug AV system using the OPERA power-line channel models. In particular, the proposed channel estimation exploits the sounding procedure available in HomePlug AV, by averaging the estimates of the channel collected during several received frames. To allow the channel estimation to properly work also in the case of a non ideal frame synchronization, a method to estimate the frame synchronization offset between successive frames is presented. Numerical results, in terms of BER versus signal-to-noise ratio, show that the performance of the proposed channel estimation almost overlaps the performance achieved with perfect channel knowledge.
{"title":"Improved HomePlug AV channel estimation exploiting sounding procedure","authors":"R. Riva, Marco Odoni, E. Guerrini, P. Bisaglia","doi":"10.1109/ISPLC.2009.4913446","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913446","url":null,"abstract":"In this paper we investigate channel estimation in the context of the OFDM-based HomePlug AV system using the OPERA power-line channel models. In particular, the proposed channel estimation exploits the sounding procedure available in HomePlug AV, by averaging the estimates of the channel collected during several received frames. To allow the channel estimation to properly work also in the case of a non ideal frame synchronization, a method to estimate the frame synchronization offset between successive frames is presented. Numerical results, in terms of BER versus signal-to-noise ratio, show that the performance of the proposed channel estimation almost overlaps the performance achieved with perfect channel knowledge.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"24 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133105689","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913404
C. Rodríguez-Morcillo, A. Rubinstein, M. Rubinstein, F. Rachidi, A. Vukičević
In this paper, we test experimentally the hypothesis that the common mode current at any point in an in-house electrical network can be calculated as the linear combination of two types of sources, namely the input differential mode voltages and the input common mode currents. The results show an excellent agreement between theory and measurements, thus lending strong support to the hypothesis.
{"title":"Experimental verification of common-mode current generation in home electrical wiring in the Powerline Communications Band","authors":"C. Rodríguez-Morcillo, A. Rubinstein, M. Rubinstein, F. Rachidi, A. Vukičević","doi":"10.1109/ISPLC.2009.4913404","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913404","url":null,"abstract":"In this paper, we test experimentally the hypothesis that the common mode current at any point in an in-house electrical network can be calculated as the linear combination of two types of sources, namely the input differential mode voltages and the input common mode currents. The results show an excellent agreement between theory and measurements, thus lending strong support to the hypothesis.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115380839","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913411
L. P. Do, R. Lehnert
Based on the available power line structure, a PLC network is configured as a multiple cells network, including several adjacent access and in-home cells. In a PLC cell, the users are not moving but their statuses and traffic demands are changing during the run-time. These cells may interference with each other; therefore, each cell has a fixed amount of transmission capacity for its transmissions. The transmission capacity is defined as a set of channels. Since the active users and traffic demands in each cell are variable, the users in different cells may get different amount of resource for their transmission. This situation leads to the problem of unfairness between users. Furthermore, when the cells are not interfering, they can use the same channels for their parallel transmissions. The overall multi-cell structure may also change dynamically due to the activation and deactivation of some cells, which requires a method for re-arranging the allocated channels between the working cells. Therefore, a method which allows the dynamic sharing of the transmission capacity between the cells is required. In this paper, we propose a negotiation strategy to allow the cells to cooperate and dynamically share the channels in a distributed fashion. The negotiation strategy is based on two procedures, seizing the channels if they are free and releasing channels if a cell has more channels per user than its neighbors. The proposal is analyzed and several aspects are discussed in this paper.
{"title":"Distributed dynamic resource allocation for multi-cell PLC networks","authors":"L. P. Do, R. Lehnert","doi":"10.1109/ISPLC.2009.4913411","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913411","url":null,"abstract":"Based on the available power line structure, a PLC network is configured as a multiple cells network, including several adjacent access and in-home cells. In a PLC cell, the users are not moving but their statuses and traffic demands are changing during the run-time. These cells may interference with each other; therefore, each cell has a fixed amount of transmission capacity for its transmissions. The transmission capacity is defined as a set of channels. Since the active users and traffic demands in each cell are variable, the users in different cells may get different amount of resource for their transmission. This situation leads to the problem of unfairness between users. Furthermore, when the cells are not interfering, they can use the same channels for their parallel transmissions. The overall multi-cell structure may also change dynamically due to the activation and deactivation of some cells, which requires a method for re-arranging the allocated channels between the working cells. Therefore, a method which allows the dynamic sharing of the transmission capacity between the cells is required. In this paper, we propose a negotiation strategy to allow the cells to cooperate and dynamically share the channels in a distributed fashion. The negotiation strategy is based on two procedures, seizing the channels if they are free and releasing channels if a cell has more channels per user than its neighbors. The proposal is analyzed and several aspects are discussed in this paper.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"126 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116371461","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913397
M. Tlich, Hassina Chaouche, A. Zeddam, P. Pagani
The electrical appliances shared with PLC modems in the same powerline network generate noises. Among them, impulsive noises are the main source of interference resulting in signal distortions and bit errors during data transmission. Many impulsive noise models were proposed in the literature. They share the same impulsive noise definition: “unpredictable noises measured at the receiver side”. This definition leads to the modelling of thousands of impulsive noises whose plurality would very likely come from the diversity of paths that the original impulsive noise took. In this paper, an innovative modelling approach is applied to impulsive noises which are henceforth studied directly at their sources. Noise at the receiver is considered as the noise model at the source filtered by the powerline channel. Effective in-device sources of impulsive noises are identified and classified into six classes, from which representative noises are proposed. Based on impulsive modelling at source, a receiver side model is finally proposed.
{"title":"Novel approach for PLC impulsive noise modelling","authors":"M. Tlich, Hassina Chaouche, A. Zeddam, P. Pagani","doi":"10.1109/ISPLC.2009.4913397","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913397","url":null,"abstract":"The electrical appliances shared with PLC modems in the same powerline network generate noises. Among them, impulsive noises are the main source of interference resulting in signal distortions and bit errors during data transmission. Many impulsive noise models were proposed in the literature. They share the same impulsive noise definition: “unpredictable noises measured at the receiver side”. This definition leads to the modelling of thousands of impulsive noises whose plurality would very likely come from the diversity of paths that the original impulsive noise took. In this paper, an innovative modelling approach is applied to impulsive noises which are henceforth studied directly at their sources. Noise at the receiver is considered as the noise model at the source filtered by the powerline channel. Effective in-device sources of impulsive noises are identified and classified into six classes, from which representative noises are proposed. Based on impulsive modelling at source, a receiver side model is finally proposed.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128591372","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913455
A. Sanz, J.I. Garcia-Nicolas, P. Estopiñán, S. Miguel
This paper describes the process of evolution of PRIME form the early definition state to the first implementation of a SoC solution. PRIME is the Draft Standard for Power-line-Related Intelligent Metering Evolution. It is a complete draft standard for a new OFDM-based power line technology for the provision of all kinds of Smart Grid services over electricity distribution networks. Both PHY and MAC layers according to IEEE conventions, plus a Convergence layer, are described in the standard. PRIME is the base line technology of the new Open Meter project supported by larger European utilities. PRIME is oriented to provide a low cost, and very robust communication channel in applications as Automated Meter Reading or Automated Meter Management. The average transmission rate of PHY layer is around 70 kbps and the maximum is 120 kbps using from 42 kHz to 88 kHz.
{"title":"PRIME from the definition to a SoC solution","authors":"A. Sanz, J.I. Garcia-Nicolas, P. Estopiñán, S. Miguel","doi":"10.1109/ISPLC.2009.4913455","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913455","url":null,"abstract":"This paper describes the process of evolution of PRIME form the early definition state to the first implementation of a SoC solution. PRIME is the Draft Standard for Power-line-Related Intelligent Metering Evolution. It is a complete draft standard for a new OFDM-based power line technology for the provision of all kinds of Smart Grid services over electricity distribution networks. Both PHY and MAC layers according to IEEE conventions, plus a Convergence layer, are described in the standard. PRIME is the base line technology of the new Open Meter project supported by larger European utilities. PRIME is oriented to provide a low cost, and very robust communication channel in applications as Automated Meter Reading or Automated Meter Management. The average transmission rate of PHY layer is around 70 kbps and the maximum is 120 kbps using from 42 kHz to 88 kHz.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"353 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121707153","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913403
Y. Akeboshi, H. Ohashi, S. Saito
In order to construct large networks in PLC system, FDM (Frequency Division Multiplexing) or TDM (Time Division Multiplexing) access scheme is often used. In general, the FDM is better solution for the systems which require real-time performance, but interference signals from adjacent sub-networks must be rejected by the analog filters to prevent the receiving sensitivity degradation of the desired signals. In this paper, a novel filter circuit, called “Multi-Band Filters”, is proposed to realize analog band-pass filter banks. The design method and the measurement results of the frequency characteristics of the Multi-band Filters are shown in this paper. By rejecting the interference signal with the Multi-band Filters, the equivalent SNR improvement of 10dB is confirmed by data rate measurement.
{"title":"Multi-Band Filters for Frequency Division Multiplexing networks in power line communications","authors":"Y. Akeboshi, H. Ohashi, S. Saito","doi":"10.1109/ISPLC.2009.4913403","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913403","url":null,"abstract":"In order to construct large networks in PLC system, FDM (Frequency Division Multiplexing) or TDM (Time Division Multiplexing) access scheme is often used. In general, the FDM is better solution for the systems which require real-time performance, but interference signals from adjacent sub-networks must be rejected by the analog filters to prevent the receiving sensitivity degradation of the desired signals. In this paper, a novel filter circuit, called “Multi-Band Filters”, is proposed to realize analog band-pass filter banks. The design method and the measurement results of the frequency characteristics of the Multi-band Filters are shown in this paper. By rejecting the interference signal with the Multi-band Filters, the equivalent SNR improvement of 10dB is confirmed by data rate measurement.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125234761","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 : 2009-05-08DOI: 10.1109/ISPLC.2009.4913439
M. Mannah, C. Batard, N. Ginot, M. Machmoun
In an Industrial application, the motor is powered and controlled by an inverter. Control and diagnostic information are transmitted back from the motor to the inverter through an extra cable dedicated for data transmission. This signal information can be sent through the feeder cable that powers the motor using the Power Line communication technology ‘PLC’. The existing PLC modems developed for domestic applications may not be suitable for data transmission over feeder cables. We will propose a PLC modem with convenient characteristics that fit for the industry. It will help us to send control information such as rotor position and temperature back to the inverter through the feeder cable already polluted by the PWM signal. Therefore, some of the modem aspects will be revealed in this paper. Studies carried out on modulation's techniques and throughput in question will help us to define the frequencies to use. We will highlight the difficulties and limitations that obstruct transmission between the motor and the inverter. We will underline the real cause of non-functioning and the possible way to overcome it. Finally, we will define the coupling interface and the modem characteristics and the frequency's band that might be convenient. Simulations and experimental results will confirm the proposed analyses and will put in evidence the achievable performance of the proposed PLC modem.
{"title":"Power Line communication over feeder cables in an Industrial environment","authors":"M. Mannah, C. Batard, N. Ginot, M. Machmoun","doi":"10.1109/ISPLC.2009.4913439","DOIUrl":"https://doi.org/10.1109/ISPLC.2009.4913439","url":null,"abstract":"In an Industrial application, the motor is powered and controlled by an inverter. Control and diagnostic information are transmitted back from the motor to the inverter through an extra cable dedicated for data transmission. This signal information can be sent through the feeder cable that powers the motor using the Power Line communication technology ‘PLC’. The existing PLC modems developed for domestic applications may not be suitable for data transmission over feeder cables. We will propose a PLC modem with convenient characteristics that fit for the industry. It will help us to send control information such as rotor position and temperature back to the inverter through the feeder cable already polluted by the PWM signal. Therefore, some of the modem aspects will be revealed in this paper. Studies carried out on modulation's techniques and throughput in question will help us to define the frequencies to use. We will highlight the difficulties and limitations that obstruct transmission between the motor and the inverter. We will underline the real cause of non-functioning and the possible way to overcome it. Finally, we will define the coupling interface and the modem characteristics and the frequency's band that might be convenient. Simulations and experimental results will confirm the proposed analyses and will put in evidence the achievable performance of the proposed PLC modem.","PeriodicalId":321296,"journal":{"name":"2009 IEEE International Symposium on Power Line Communications and Its Applications","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134629446","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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