Pub Date : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797539
A. Tajer, Xiaodong Wang
Multiple-antenna downlink transmission offers significant capacity improvement when the transmit-side channel state information (CSI) is available. The sum-rate capacity with infinite-rate feedback (full or partial CSI) scales linearly with the number of transmit antennas (multiplexing gain) and double logarithmically with the number of users (multiuser diversity gain). In this paper we present a new scheduling scheme which requires only finite-rate feedback and yet retains the optimal multiplexing and multiuser diversity gains achievable by dirty-paper coding and show that its sum-rate throughput scales like Nt log log KNr where Nt and Nr are the number of transmit and receive antennas and K is the number of users. While our scheduling schemes is asymptotically optimal, it also exhibits a good performance for practical network sizes. We also show that by appropriate design of the feedback mechanism, we can refrain the aggregate amount of feedback from increasing with the number of users and for asymptotically large networks the total number of feedback bits is bounded by Nt log Nt. We also demonstrate that despite having an opportunistic user selection, fairness among the users is maintained and all are equality likely to be scheduled.
{"title":"Opportunistic multi-antenna downlink transmission with finite-rate feedback","authors":"A. Tajer, Xiaodong Wang","doi":"10.1109/ALLERTON.2008.4797539","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797539","url":null,"abstract":"Multiple-antenna downlink transmission offers significant capacity improvement when the transmit-side channel state information (CSI) is available. The sum-rate capacity with infinite-rate feedback (full or partial CSI) scales linearly with the number of transmit antennas (multiplexing gain) and double logarithmically with the number of users (multiuser diversity gain). In this paper we present a new scheduling scheme which requires only finite-rate feedback and yet retains the optimal multiplexing and multiuser diversity gains achievable by dirty-paper coding and show that its sum-rate throughput scales like Nt log log KNr where Nt and Nr are the number of transmit and receive antennas and K is the number of users. While our scheduling schemes is asymptotically optimal, it also exhibits a good performance for practical network sizes. We also show that by appropriate design of the feedback mechanism, we can refrain the aggregate amount of feedback from increasing with the number of users and for asymptotically large networks the total number of feedback bits is bounded by Nt log Nt. We also demonstrate that despite having an opportunistic user selection, fairness among the users is maintained and all are equality likely to be scheduled.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130770326","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797740
A. Pantelidou, A. Ephremides
We consider a system of multiple multicast transmitters with possibly overlapping receivers. We introduce a stationary policy that allocates the transmission rates and powers of every transmitter with the objective to maximize the overall user utility, which is measured in terms of the total average rate of each receiver. We show optimality of this policy by employing the theory of stochastic approximation for any utility function that is strictly concave and increasing in the average rate. The introduced policy is opportunistic in nature as it capitalizes on the variations of the wireless channel that are induced by fading. Specifically, we show through a set of simulations that the average throughput under unicast traffic observes a benefit under fading. Our results further indicate that this benefit is mitigated when multicast traffic is considered.
{"title":"A cross-layer view of wireless multicast optimization","authors":"A. Pantelidou, A. Ephremides","doi":"10.1109/ALLERTON.2008.4797740","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797740","url":null,"abstract":"We consider a system of multiple multicast transmitters with possibly overlapping receivers. We introduce a stationary policy that allocates the transmission rates and powers of every transmitter with the objective to maximize the overall user utility, which is measured in terms of the total average rate of each receiver. We show optimality of this policy by employing the theory of stochastic approximation for any utility function that is strictly concave and increasing in the average rate. The introduced policy is opportunistic in nature as it capitalizes on the variations of the wireless channel that are induced by fading. Specifically, we show through a set of simulations that the average throughput under unicast traffic observes a benefit under fading. Our results further indicate that this benefit is mitigated when multicast traffic is considered.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"20 17","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120823555","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797686
H. Tembine, E. Altman, R. Elazouzi, Y. Hayel
We study a class of population game frameworks called stable games, introduced by Hofbauer and Sandholm (2007). We give several examples of applications of stable population games in the context of wireless networks including resource allocation, impact of malicious users in cognitive radio networks and power control. We model and analyze a base station assignment problem and interference control scenarios in heterogeneous wireless networks as a non-zero sum stable game. We show that the resource selection game has a unique evolutionary stable strategy (ESS) and a unique correlated ESS. We give a class of evolutionary game dynamics to lead to the ESS.
{"title":"Stable networking games","authors":"H. Tembine, E. Altman, R. Elazouzi, Y. Hayel","doi":"10.1109/ALLERTON.2008.4797686","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797686","url":null,"abstract":"We study a class of population game frameworks called stable games, introduced by Hofbauer and Sandholm (2007). We give several examples of applications of stable population games in the context of wireless networks including resource allocation, impact of malicious users in cognitive radio networks and power control. We model and analyze a base station assignment problem and interference control scenarios in heterogeneous wireless networks as a non-zero sum stable game. We show that the resource selection game has a unique evolutionary stable strategy (ESS) and a unique correlated ESS. We give a class of evolutionary game dynamics to lead to the ESS.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131370052","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797726
J. Kliewer, K. Zigangirov, D. J. Costello
We consider the ensemble of codes formed by a serial concatenation of a repetition code with two accumulators through uniform random interleavers. For this ensemble, asymptotic expressions for the normalized minimum trapping distance are derived. We employ a variant of the Gallager-Zyablov-Pinsker bit flipping decoding algorithm on a binary symmetric channel, where the analysis is based on the factor graph of the code. In particular, we show that the minimum trapping distance can be determined by solving a non-linear optimization problem. As a result we find that the minimum trapping distance grows linearly with block length for code rates of 1/3 and smaller, albeit with very small growth rate coefficients.
{"title":"On the minimum trapping distance of repeat accumulate accumulate codes","authors":"J. Kliewer, K. Zigangirov, D. J. Costello","doi":"10.1109/ALLERTON.2008.4797726","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797726","url":null,"abstract":"We consider the ensemble of codes formed by a serial concatenation of a repetition code with two accumulators through uniform random interleavers. For this ensemble, asymptotic expressions for the normalized minimum trapping distance are derived. We employ a variant of the Gallager-Zyablov-Pinsker bit flipping decoding algorithm on a binary symmetric channel, where the analysis is based on the factor graph of the code. In particular, we show that the minimum trapping distance can be determined by solving a non-linear optimization problem. As a result we find that the minimum trapping distance grows linearly with block length for code rates of 1/3 and smaller, albeit with very small growth rate coefficients.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"283 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124522592","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797716
S. Puducheri, T. Fuja
We study the tradeoffs in employing two different approaches - coding and feedback - for reliable communication over packet erasure channels. Results are shown for a scheme that combines both approaches. Inspired by this scheme, we use rate distortion results to characterize the best achievable tradeoffs for a class of joint coding-and-feedback schemes.
{"title":"Trading off coding complexity and feedback requirements for the packet erasure channel","authors":"S. Puducheri, T. Fuja","doi":"10.1109/ALLERTON.2008.4797716","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797716","url":null,"abstract":"We study the tradeoffs in employing two different approaches - coding and feedback - for reliable communication over packet erasure channels. Results are shown for a scheme that combines both approaches. Inspired by this scheme, we use rate distortion results to characterize the best achievable tradeoffs for a class of joint coding-and-feedback schemes.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115767118","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797671
Sungho Yun, C. Caramanis
We consider a system-level approach to interference management in a cellular broadband system operating in an interference-limited and highly dynamic regime, as put forth. Here, base stations in neighboring cells (partially) coordinate their transmission schedules in an attempt to avoid simultaneous transmission to their mutual cell edge. Limits on communication overhead and use of the backhaul require base station coordination to occur at a slower time scale than the arriving customers. Depending on the overhead restrictions, the slower time scale could be on the scale of minutes or even hours. Thus base stations coordinate using only the statistics of customer arrival, while they serve users based on the actual realizations. The central challenge is to properly structure coordination decisions at the slow time scale, as these subsequently restrict the actions of each base station until the next coordination period. A further challenge comes from the fact that over longer coordination intervals, the statistics of the arriving customers, e.g., the load, may themselves vary or be only approximately known. Indeed, we show through simulation that while the approach is effective for a broad range of arriving load, performance rapidly degrades as the variation of the arriving load from the nominal (or assured) arriving load grows. We show this is true even when the variations are neutral, namely when the aggregate load is fixed, but there are local variations. In this paper we show that a two-stage robust optimization framework is a natural way to model two time-scale decision problems. We provide tractable formulations for the base- station coordination problem, and show that our formulation is robust to fluctuations (uncertainties) in the arriving load. This tolerance to load fluctuation also serves to reduce the need for frequent re-optimization across base stations, thus helping minimize the communication overhead required for system level interference reduction. Building in robustness to load variation comes at the potential cost of somewhat degraded performance when variations happen to be very small. Our robust optimization formulations are flexible, allowing us to control the conservatism of the solution. Our simulations show that we can build in robustness without significant degradation of nominal performance.
{"title":"System level optimization in wireless networks with uncertain customer arrival rates","authors":"Sungho Yun, C. Caramanis","doi":"10.1109/ALLERTON.2008.4797671","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797671","url":null,"abstract":"We consider a system-level approach to interference management in a cellular broadband system operating in an interference-limited and highly dynamic regime, as put forth. Here, base stations in neighboring cells (partially) coordinate their transmission schedules in an attempt to avoid simultaneous transmission to their mutual cell edge. Limits on communication overhead and use of the backhaul require base station coordination to occur at a slower time scale than the arriving customers. Depending on the overhead restrictions, the slower time scale could be on the scale of minutes or even hours. Thus base stations coordinate using only the statistics of customer arrival, while they serve users based on the actual realizations. The central challenge is to properly structure coordination decisions at the slow time scale, as these subsequently restrict the actions of each base station until the next coordination period. A further challenge comes from the fact that over longer coordination intervals, the statistics of the arriving customers, e.g., the load, may themselves vary or be only approximately known. Indeed, we show through simulation that while the approach is effective for a broad range of arriving load, performance rapidly degrades as the variation of the arriving load from the nominal (or assured) arriving load grows. We show this is true even when the variations are neutral, namely when the aggregate load is fixed, but there are local variations. In this paper we show that a two-stage robust optimization framework is a natural way to model two time-scale decision problems. We provide tractable formulations for the base- station coordination problem, and show that our formulation is robust to fluctuations (uncertainties) in the arriving load. This tolerance to load fluctuation also serves to reduce the need for frequent re-optimization across base stations, thus helping minimize the communication overhead required for system level interference reduction. Building in robustness to load variation comes at the potential cost of somewhat degraded performance when variations happen to be very small. Our robust optimization formulations are flexible, allowing us to control the conservatism of the solution. Our simulations show that we can build in robustness without significant degradation of nominal performance.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114854383","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797627
E. Larsson, D. Danev, Eduard Axel Jorswieck
We consider the interference channel with multiple antennas at the transmitter. We prove that at high signal-to-noise ratio (SNR), the zero-forcing transmit scheme is optimal in the sum-rate sense. Furthermore we prove that at low SNR, maximum-ratio transmission is optimal in the sum-rate sense. We also provide a discussion of the connection to classical results on spectral efficiency in the wideband regime. Finally, we propose a non-convex optimization approach based on monotonic optimization to solve the sum rate maximization problem.
{"title":"Asymptotically optimal transmit strategies for the multiple antenna interference channel","authors":"E. Larsson, D. Danev, Eduard Axel Jorswieck","doi":"10.1109/ALLERTON.2008.4797627","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797627","url":null,"abstract":"We consider the interference channel with multiple antennas at the transmitter. We prove that at high signal-to-noise ratio (SNR), the zero-forcing transmit scheme is optimal in the sum-rate sense. Furthermore we prove that at low SNR, maximum-ratio transmission is optimal in the sum-rate sense. We also provide a discussion of the connection to classical results on spectral efficiency in the wideband regime. Finally, we propose a non-convex optimization approach based on monotonic optimization to solve the sum rate maximization problem.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"282 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126916090","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797699
P. Tague, R. Poovendran
We formalize a model for node capture attacks in which an adversary collects information about the network via eavesdropping on the wireless medium and captures nodes based on the learned information. We show that attacks in this adversary model correspond to NP-hard optimization problems and discuss the behavior of a reasonable heuristic algorithm. We show that the goals of node capture attacks can be decomposed into a collection of primitive events, the impact of which can be evaluated and recombined to yield an overall evaluation of the attack. We demonstrate the use of the attack decomposition model for derivation of attack metrics and discuss the potential use of this decomposition technique for the purposes of defense against node capture attacks.
{"title":"Modeling node capture attacks in wireless sensor networks","authors":"P. Tague, R. Poovendran","doi":"10.1109/ALLERTON.2008.4797699","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797699","url":null,"abstract":"We formalize a model for node capture attacks in which an adversary collects information about the network via eavesdropping on the wireless medium and captures nodes based on the learned information. We show that attacks in this adversary model correspond to NP-hard optimization problems and discuss the behavior of a reasonable heuristic algorithm. We show that the goals of node capture attacks can be decomposed into a collection of primitive events, the impact of which can be evaluated and recombined to yield an overall evaluation of the attack. We demonstrate the use of the attack decomposition model for derivation of attack metrics and discuss the potential use of this decomposition technique for the purposes of defense against node capture attacks.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127055960","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797704
C. Kelley
Over the past few years several constructions of protograph codes have been proposed that are based on random lifts of suitably chosen base graphs. More recently, an algebraic analog of this approach was introduced using the theory of voltage graphs. The strength of the voltage graph framework is the ability to analyze the resulting derived graph algebraically, even when the voltages themselves are assigned randomly. Moreover, the theory of voltage graphs provides insight to designing lifts of graphs with particular properties. In this paper we illustrate how the properties of the derived graphs and the corresponding codes relate to the voltage assignments. In particular, we present a construction of LDPC codes by giving an algebraic method of choosing the permutation voltages and illustrate the usefulness of the proposed technique via simulation results.
{"title":"On codes designed via algebraic lifts of graphs","authors":"C. Kelley","doi":"10.1109/ALLERTON.2008.4797704","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797704","url":null,"abstract":"Over the past few years several constructions of protograph codes have been proposed that are based on random lifts of suitably chosen base graphs. More recently, an algebraic analog of this approach was introduced using the theory of voltage graphs. The strength of the voltage graph framework is the ability to analyze the resulting derived graph algebraically, even when the voltages themselves are assigned randomly. Moreover, the theory of voltage graphs provides insight to designing lifts of graphs with particular properties. In this paper we illustrate how the properties of the derived graphs and the corresponding codes relate to the voltage assignments. In particular, we present a construction of LDPC codes by giving an algebraic method of choosing the permutation voltages and illustrate the usefulness of the proposed technique via simulation results.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127307889","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 : 2008-09-01DOI: 10.1109/ALLERTON.2008.4797609
R. Nowak
This paper studies a generalization of the classic binary search problem of locating a desired value within a sorted list. The classic problem can be viewed as determining the correct one-dimensional, binary-valued threshold function from a finite class of such functions based on queries taking the form of point samples of the function. The classic problem is also equivalent to a simple binary encoding of the threshold location. This paper extends binary search to learning more general binary-valued functions. Specifically, if the set of target functions and queries satisfy certain geometrical relationships, then an algorithm, based on selecting a query that is maximally discriminating at each step, will determine the correct function in a number of steps that is logarithmic in the number of functions under consideration. Examples of classes satisfying the geometrical relationships include linear separators in multiple dimensions. Extensions to handle noise are also discussed. Possible applications include machine learning, channel coding, and sequential experimental design.
{"title":"Generalized binary search","authors":"R. Nowak","doi":"10.1109/ALLERTON.2008.4797609","DOIUrl":"https://doi.org/10.1109/ALLERTON.2008.4797609","url":null,"abstract":"This paper studies a generalization of the classic binary search problem of locating a desired value within a sorted list. The classic problem can be viewed as determining the correct one-dimensional, binary-valued threshold function from a finite class of such functions based on queries taking the form of point samples of the function. The classic problem is also equivalent to a simple binary encoding of the threshold location. This paper extends binary search to learning more general binary-valued functions. Specifically, if the set of target functions and queries satisfy certain geometrical relationships, then an algorithm, based on selecting a query that is maximally discriminating at each step, will determine the correct function in a number of steps that is logarithmic in the number of functions under consideration. Examples of classes satisfying the geometrical relationships include linear separators in multiple dimensions. Extensions to handle noise are also discussed. Possible applications include machine learning, channel coding, and sequential experimental design.","PeriodicalId":120561,"journal":{"name":"2008 46th Annual Allerton Conference on Communication, Control, and Computing","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122955738","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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