Pub Date : 2017-09-01DOI: 10.1109/VTCFall.2017.8287999
A. Heidarpour, M. Ardakani, C. Tellambura
In this paper, we investigate the performance of network coded cooperation (NCC) systems based on relay selection in the presence of imperfect channel state information (CSI). Specifically, we consider an uplink cellular scenario with $mathcal{N}$ sources, $mathcal{M}$ relays and a single destination. The relays adopt decode and forward (DF) relaying and use maximum distance separable (MDS) codes as their encoding vectors. We investigate the impact of imperfect CSI on outage probability and asymptotic and finite-SNR diversity-multiplexing tradeoff (DMT) of the system under consideration. Simulation results are further presented to corroborate the analytical findings and provide insight into the system design where imperfect CSI and finite SNR regime are taken into account.
{"title":"Network Coded Cooperation Based on Relay Selection with Imperfect CSI","authors":"A. Heidarpour, M. Ardakani, C. Tellambura","doi":"10.1109/VTCFall.2017.8287999","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8287999","url":null,"abstract":"In this paper, we investigate the performance of network coded cooperation (NCC) systems based on relay selection in the presence of imperfect channel state information (CSI). Specifically, we consider an uplink cellular scenario with $mathcal{N}$ sources, $mathcal{M}$ relays and a single destination. The relays adopt decode and forward (DF) relaying and use maximum distance separable (MDS) codes as their encoding vectors. We investigate the impact of imperfect CSI on outage probability and asymptotic and finite-SNR diversity-multiplexing tradeoff (DMT) of the system under consideration. Simulation results are further presented to corroborate the analytical findings and provide insight into the system design where imperfect CSI and finite SNR regime are taken into account.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"302 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115372128","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8288030
F. Penna, Hongbin Cheng, Jungwon Lee
In this paper, we propose a novel method for selecting the precoding matrix indicator (PMI) from a DFT-based codebook, such as the one specified for LTE full dimension (FD) MIMO. While conventional approaches are based on explicit codebook search, our method directly estimates the best PMI from the singular vectors of the channel matrix. The key idea is to exploit the DFT structure to formulate the PMI selection problem as the estimation of the linear phase ramping of a sequence. The main advantage of the proposed method is that its complexity does not scale with the number of PMI candidates, while achieving performance comparable or superior to that of state-of-the-art search-based approaches.
{"title":"A Search-Free Algorithm for Precoder Selection in FD-MIMO Systems with DFT-Based Codebooks","authors":"F. Penna, Hongbin Cheng, Jungwon Lee","doi":"10.1109/VTCFall.2017.8288030","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8288030","url":null,"abstract":"In this paper, we propose a novel method for selecting the precoding matrix indicator (PMI) from a DFT-based codebook, such as the one specified for LTE full dimension (FD) MIMO. While conventional approaches are based on explicit codebook search, our method directly estimates the best PMI from the singular vectors of the channel matrix. The key idea is to exploit the DFT structure to formulate the PMI selection problem as the estimation of the linear phase ramping of a sequence. The main advantage of the proposed method is that its complexity does not scale with the number of PMI candidates, while achieving performance comparable or superior to that of state-of-the-art search-based approaches.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115474708","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}
The limited computing ability of mobile device constrains its performance on complex mobile applications. Mobile cloud computing (MCC) has therefore emerged to migrate computation-intensive tasks to remote clouds or mobile cloudlets. Most strategies allocate tasks with minimal response time yet few consider the load of the nodes. In this paper, we focus on the load balancing problem for nodes when they conduct offloading. We first establish a five-tuple characterized task model to capture the response time of offloaded tasks. Then, we formulate the task allocation problem as an integer linear problem (ILP) under certain conditions. Furthermore, we propose a two-step appointment- driven strategy to solve this problem with minimal task response time. Specifically, a modified genetic algorithm (GA) is adopted to coordinate the load of the nodes. Simulations are conducted to prove the feasibility of our strategy and evaluate the performance of load coordination.
{"title":"Load Balancing Oriented Computation Offloading in Mobile Cloudlet","authors":"Danhui Yao, Lin Gui, Fen Hou, Fei Sun, Daihui Mo, Hangguan Shan","doi":"10.1109/VTCFall.2017.8288336","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8288336","url":null,"abstract":"The limited computing ability of mobile device constrains its performance on complex mobile applications. Mobile cloud computing (MCC) has therefore emerged to migrate computation-intensive tasks to remote clouds or mobile cloudlets. Most strategies allocate tasks with minimal response time yet few consider the load of the nodes. In this paper, we focus on the load balancing problem for nodes when they conduct offloading. We first establish a five-tuple characterized task model to capture the response time of offloaded tasks. Then, we formulate the task allocation problem as an integer linear problem (ILP) under certain conditions. Furthermore, we propose a two-step appointment- driven strategy to solve this problem with minimal task response time. Specifically, a modified genetic algorithm (GA) is adopted to coordinate the load of the nodes. Simulations are conducted to prove the feasibility of our strategy and evaluate the performance of load coordination.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124254572","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8288091
Ngoc-Dung Dào, H. Farmanbar, Han Zhang
In this paper, we present low-complexity algorithms for cache placement problem in software-defined radio access networks. Our key design target is that the packet delay from any cache to its associated users is below a threshold. This feature is a significant improvement compared to conventional approaches relying on the average hop count. We introduce a traffic engineering solution for joint multiserver selection and rate allocation. This algorithm is used to minimize the cache placement cost function, such as delivery cost per bit. Our cache placement method allows prediction of user throughput and thus the network throughput. Extensive simulation results verify that our method can give optimal or near optimal network throughput while guaranteeing packet delay performance.
{"title":"Cache Placement Solutions in Software-Defined Radio Access Networks","authors":"Ngoc-Dung Dào, H. Farmanbar, Han Zhang","doi":"10.1109/VTCFall.2017.8288091","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8288091","url":null,"abstract":"In this paper, we present low-complexity algorithms for cache placement problem in software-defined radio access networks. Our key design target is that the packet delay from any cache to its associated users is below a threshold. This feature is a significant improvement compared to conventional approaches relying on the average hop count. We introduce a traffic engineering solution for joint multiserver selection and rate allocation. This algorithm is used to minimize the cache placement cost function, such as delivery cost per bit. Our cache placement method allows prediction of user throughput and thus the network throughput. Extensive simulation results verify that our method can give optimal or near optimal network throughput while guaranteeing packet delay performance.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124264594","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8288121
Jing Zhang, Guoheng Liu, Yan Liao, Qingjie Zhou, Qiang Li
This paper studies the fairness for energy efficient in multi-tier downlink heterogeneous cellular networks (HCNs), where user equipments (UEs) can receive information and harvest energy from wireless power transfer. To balance the UEs received information and harvested energy in HCNs, we proposed an energy-efficiency-based proportionally fairness utility function. Based on the analysis for transmission rate and harvested energy of UEs, we show the energy-efficiency-based proportionally fairness is concave function for received threshold when association probability is fixed. Exploiting alternative programming for joint association probability and received threshold, we propose an efficient iterative algorithm for obtaining the suboptimal solution. Simulation results demonstrate the energy efficiency of multi-tier downlink HCNs improvement brought by the proposed suboptimal association probability and received threshold compared to the scheme that received threshold is low.
{"title":"Energy Efficiency Fairness in Heterogeneous Cellular Networks with Wireless Power Transfer","authors":"Jing Zhang, Guoheng Liu, Yan Liao, Qingjie Zhou, Qiang Li","doi":"10.1109/VTCFall.2017.8288121","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8288121","url":null,"abstract":"This paper studies the fairness for energy efficient in multi-tier downlink heterogeneous cellular networks (HCNs), where user equipments (UEs) can receive information and harvest energy from wireless power transfer. To balance the UEs received information and harvested energy in HCNs, we proposed an energy-efficiency-based proportionally fairness utility function. Based on the analysis for transmission rate and harvested energy of UEs, we show the energy-efficiency-based proportionally fairness is concave function for received threshold when association probability is fixed. Exploiting alternative programming for joint association probability and received threshold, we propose an efficient iterative algorithm for obtaining the suboptimal solution. Simulation results demonstrate the energy efficiency of multi-tier downlink HCNs improvement brought by the proposed suboptimal association probability and received threshold compared to the scheme that received threshold is low.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"35 38","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120821429","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8288018
O. Saatlou, M. Ahmad, M. Swamy
This paper studies the problem of maximizing the spectral efficiency in a massive multi-user MIMO downlink (DL) system where the base station employs a large number of antennas and serves single-antenna users in one cell, assuming time- division duplex transmission. In order to maximize the spectral efficiency in a DL transmission, a new method for power allocation among users is proposed based on the water-filling approach. To this end, a lower bound on the achievable rate is derived for each user in the presence of maximum- ratio transmission precoding and employed in defining the spectral efficiency. Since maximizing the spectral efficiency is an NP-hard problem, an effective algorithm is also proposed to find Karush-Kuhn-Tucker (local maximum) points. The performance of the proposed power allocation method is verified by conducting simulations and shown to be superior to other existing methods in terms of higher spectral efficiency.
{"title":"Spectral Efficiency Maximization for Massive Multiuser MIMO Downlink TDD Systems via Data Power Allocation with MRT Precoding","authors":"O. Saatlou, M. Ahmad, M. Swamy","doi":"10.1109/VTCFall.2017.8288018","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8288018","url":null,"abstract":"This paper studies the problem of maximizing the spectral efficiency in a massive multi-user MIMO downlink (DL) system where the base station employs a large number of antennas and serves single-antenna users in one cell, assuming time- division duplex transmission. In order to maximize the spectral efficiency in a DL transmission, a new method for power allocation among users is proposed based on the water-filling approach. To this end, a lower bound on the achievable rate is derived for each user in the presence of maximum- ratio transmission precoding and employed in defining the spectral efficiency. Since maximizing the spectral efficiency is an NP-hard problem, an effective algorithm is also proposed to find Karush-Kuhn-Tucker (local maximum) points. The performance of the proposed power allocation method is verified by conducting simulations and shown to be superior to other existing methods in terms of higher spectral efficiency.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124986241","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8287934
Binh T. Vo, Ha H. Nguyen, H. Tuan
This paper considers constellation design for quadrature spatial modulation (QSM) to minimize the average probability of error. Different than the constellation design previously obtained for spatial modulation (SM), it is shown that, the error performance of QSM not only depends on the Euclidean distances between the amplitude-phase modulation (APM) symbols and the energies of APM symbols, but also on the in-phase and quadrature components of the QSM symbols. The analysis of the union bound of the average error probability reveals that at a very large number of transmit antennas, the optimal constellations for QSM converge to a quadrature phase-shift keying (QPSK) constellation. Simulation results demonstrate the performance superiority of the obtained constellations over the standard PSK and QAM constellations, as well as the constellations specifically designed for SM.
{"title":"Constellation Design for Quadrature Spatial Modulation","authors":"Binh T. Vo, Ha H. Nguyen, H. Tuan","doi":"10.1109/VTCFall.2017.8287934","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8287934","url":null,"abstract":"This paper considers constellation design for quadrature spatial modulation (QSM) to minimize the average probability of error. Different than the constellation design previously obtained for spatial modulation (SM), it is shown that, the error performance of QSM not only depends on the Euclidean distances between the amplitude-phase modulation (APM) symbols and the energies of APM symbols, but also on the in-phase and quadrature components of the QSM symbols. The analysis of the union bound of the average error probability reveals that at a very large number of transmit antennas, the optimal constellations for QSM converge to a quadrature phase-shift keying (QPSK) constellation. Simulation results demonstrate the performance superiority of the obtained constellations over the standard PSK and QAM constellations, as well as the constellations specifically designed for SM.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126135006","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8288116
Yutong Yan, L. Qian, Yuan Wu, Weidang Lu
Offloading data traffic from the conventional macro- cell base stations to densely deployed small-cell base stations (SBSs) has been emerging as a promising technique to support the explosion of data traffic with reduced energy consumption and improved quality of service provision. In this paper, we study the joint spectrum allocation and power allocation problem for the data offloading in energy-harvesting downlink small-cell networks. First, we formulate the resource allocation problem under the revenue maximization criterion, which is expressed as the difference between the total utility across users and the total power payment. By proving the convexity of the problem, we can compute the solution efficiently. Numerical results show that the energy-efficiency can be improved while alleviating the burden of macro-cell base station through using the resource allocation scheme proposed for data offloading.
{"title":"Optimal Resource Allocation for Data Offloading in Energy-Harvesting Small-Cell Networks","authors":"Yutong Yan, L. Qian, Yuan Wu, Weidang Lu","doi":"10.1109/VTCFall.2017.8288116","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8288116","url":null,"abstract":"Offloading data traffic from the conventional macro- cell base stations to densely deployed small-cell base stations (SBSs) has been emerging as a promising technique to support the explosion of data traffic with reduced energy consumption and improved quality of service provision. In this paper, we study the joint spectrum allocation and power allocation problem for the data offloading in energy-harvesting downlink small-cell networks. First, we formulate the resource allocation problem under the revenue maximization criterion, which is expressed as the difference between the total utility across users and the total power payment. By proving the convexity of the problem, we can compute the solution efficiently. Numerical results show that the energy-efficiency can be improved while alleviating the burden of macro-cell base station through using the resource allocation scheme proposed for data offloading.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125552080","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8287944
João Guerreiro, M. Beko, R. Dinis, P. Montezuma
Orthogonal frequency division multiplexing (OFDM) schemes have high envelope fluctuations and peak- to-average power ratio (PAPR), making them very prone to nonlinear distortion effects, which can affect significantly the performance when conventional receivers are employed. However, it was recently shown that strong nonlinear distortion effects on OFDM signals do not necessarily lead to performance degradation. In fact, nonlinear OFDM schemes can outperform linear ones when optimum maximum likelihood (ML) receivers are employed. In this paper, we considered OFDM schemes with strong nonlinear distortion effects and we proposed a low- complexity detection scheme able to approach the optimum ML performance. Our technique is based on the fireworks algorithm (FWA) and allows excellent trade-offs between performance and complexity.
{"title":"Using the Fireworks Algorithm for ML Detection of Nonlinear OFDM","authors":"João Guerreiro, M. Beko, R. Dinis, P. Montezuma","doi":"10.1109/VTCFall.2017.8287944","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8287944","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) schemes have high envelope fluctuations and peak- to-average power ratio (PAPR), making them very prone to nonlinear distortion effects, which can affect significantly the performance when conventional receivers are employed. However, it was recently shown that strong nonlinear distortion effects on OFDM signals do not necessarily lead to performance degradation. In fact, nonlinear OFDM schemes can outperform linear ones when optimum maximum likelihood (ML) receivers are employed. In this paper, we considered OFDM schemes with strong nonlinear distortion effects and we proposed a low- complexity detection scheme able to approach the optimum ML performance. Our technique is based on the fireworks algorithm (FWA) and allows excellent trade-offs between performance and complexity.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126606117","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 : 2017-09-01DOI: 10.1109/VTCFall.2017.8288303
Karsten Roscher, Thomas Nitsche, R. Knorr
Current advances in vehicular ad-hoc networks (VANETs) point out the importance of multi-hop message dissemination. For this type of communication, the selection of neighboring nodes with stable links is vital. In this work, we address the neighbor selection problem with a data-driven approach. To this aim, we apply machine learning techniques to a massive data-set of ETSI ITS message exchange samples, obtained from simulated traffic in the highly detailed Luxembourg SUMO Traffic (LuST) Scenario. As a result, we present classification methods that increase neighbor selection accuracy by up to 43% compared to the state of the art.
{"title":"Know Thy Neighbor - A Data-Driven Approach to Neighborhood Estimation in VANETs","authors":"Karsten Roscher, Thomas Nitsche, R. Knorr","doi":"10.1109/VTCFall.2017.8288303","DOIUrl":"https://doi.org/10.1109/VTCFall.2017.8288303","url":null,"abstract":"Current advances in vehicular ad-hoc networks (VANETs) point out the importance of multi-hop message dissemination. For this type of communication, the selection of neighboring nodes with stable links is vital. In this work, we address the neighbor selection problem with a data-driven approach. To this aim, we apply machine learning techniques to a massive data-set of ETSI ITS message exchange samples, obtained from simulated traffic in the highly detailed Luxembourg SUMO Traffic (LuST) Scenario. As a result, we present classification methods that increase neighbor selection accuracy by up to 43% compared to the state of the art.","PeriodicalId":375803,"journal":{"name":"2017 IEEE 86th Vehicular Technology Conference (VTC-Fall)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126618388","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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