Pub Date : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363453
Xizhi An, K. Kwak
In this paper, a practical location-aided routing method for sensor networks based on ultra-wideband (UWB) technique is proposed and evaluated. This method makes use of the positioning function of UWB and takes info account the energy consumption in the network. By modeling the property of energy consumption, we find that energy and quality-of-service (QOS) issues are greatly influenced by the route selected. Accordingly, a new routing algorithm is derived to search for energy-efficient routes that can support adequate QOS requirements. The simulation results have proved the advantages of this routing scheme
{"title":"A Practical Location-aided Energy-aware Routing Method for UWB-based Sensor Networks","authors":"Xizhi An, K. Kwak","doi":"10.1109/CROWNCOM.2006.363453","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363453","url":null,"abstract":"In this paper, a practical location-aided routing method for sensor networks based on ultra-wideband (UWB) technique is proposed and evaluated. This method makes use of the positioning function of UWB and takes info account the energy consumption in the network. By modeling the property of energy consumption, we find that energy and quality-of-service (QOS) issues are greatly influenced by the route selected. Accordingly, a new routing algorithm is derived to search for energy-efficient routes that can support adequate QOS requirements. The simulation results have proved the advantages of this routing scheme","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115265336","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363452
R. Rajbanshi, A. Wyglinski, G. Minden
In this paper, we present an efficient implementation of a non-contiguous orthogonal frequency division multiplexing (NC-OFDM) transceiver for cognitive radio systems. NC-OFDM is designed to transmit information in the presence of incumbent users, deactivating subcarriers located in the vicinity of these users to avoid interference. Given that the. core, component of an NC-OFDM transceiver is the fast Fourier transform (FFT), and that several of the subcarriers are deactivated, it is possible to reduce the execution time by "pruning" the FFT. We propose an algorithm that efficiently and quickly primes the FFT for NC-OFDM transceivers. Results show that the proposed algorithm substantially outperforms other FFT pruning algorithms when a medium to large number of subcarriers have been deactivated
{"title":"An Efficient Implementation of NC-OFDM Transceivers for Cognitive Radios","authors":"R. Rajbanshi, A. Wyglinski, G. Minden","doi":"10.1109/CROWNCOM.2006.363452","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363452","url":null,"abstract":"In this paper, we present an efficient implementation of a non-contiguous orthogonal frequency division multiplexing (NC-OFDM) transceiver for cognitive radio systems. NC-OFDM is designed to transmit information in the presence of incumbent users, deactivating subcarriers located in the vicinity of these users to avoid interference. Given that the. core, component of an NC-OFDM transceiver is the fast Fourier transform (FFT), and that several of the subcarriers are deactivated, it is possible to reduce the execution time by \"pruning\" the FFT. We propose an algorithm that efficiently and quickly primes the FFT for NC-OFDM transceivers. Results show that the proposed algorithm substantially outperforms other FFT pruning algorithms when a medium to large number of subcarriers have been deactivated","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128567143","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363473
M. El-Hadidy, T. Kaiser
Aim of this contribution is to study the impact of typical ultra-wideband (UWB) antennas for communications over a spatial wireless channel. In order to adequately consider the directivity properties of real antennas, out analysis is suitably based on a ray tracing UWB channel model since this reflects the dependence on the angle of arrival (AoA) and angle of departure (AoD) of any multipath. A mathematical framework is given which also allows an optimization of such an UWB multiple input multiple output (MIMO) system using different types of transmitting and receiving antennas on behalf of idealistic omnidirectional ones. Beside the angle dependence, the antenna transfer functions are without doubt frequency dependent on such a large UWB bandwidth, so that they will be evaluated with suitable analog design specialized tools for the fast and accurate three-dimensional electromagnetic simulation of high frequency circuits. Simulation results allowing concrete guidelines on the antenna influence are provided in the last section of this paper
{"title":"Impact of Ultra Wide-Band Antennas on Communications in a Spatial Cannel","authors":"M. El-Hadidy, T. Kaiser","doi":"10.1109/CROWNCOM.2006.363473","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363473","url":null,"abstract":"Aim of this contribution is to study the impact of typical ultra-wideband (UWB) antennas for communications over a spatial wireless channel. In order to adequately consider the directivity properties of real antennas, out analysis is suitably based on a ray tracing UWB channel model since this reflects the dependence on the angle of arrival (AoA) and angle of departure (AoD) of any multipath. A mathematical framework is given which also allows an optimization of such an UWB multiple input multiple output (MIMO) system using different types of transmitting and receiving antennas on behalf of idealistic omnidirectional ones. Beside the angle dependence, the antenna transfer functions are without doubt frequency dependent on such a large UWB bandwidth, so that they will be evaluated with suitable analog design specialized tools for the fast and accurate three-dimensional electromagnetic simulation of high frequency circuits. Simulation results allowing concrete guidelines on the antenna influence are provided in the last section of this paper","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"30 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133037333","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363468
P. Demestichas, G. Dimitrakopoulos, K. Tsagkaris, K. Demestichas, Evgenia F. Adamopoulou
B3G (beyond the 3rd generation) wireless infrastructures can be efficiently realized by exploiting cognitive networking concepts. Cognitive, wireless access, infrastructures can dynamically configure their transceivers with the appropriate radio access technologies (RATs) and spectrum, in order to, reactively or proactively, adapt to the environment requirements and conditions. Reconfiguration decisions call for advanced management functionality. This paper provides such management functionality by addressing a pertinent problem, called "RAT and spectrum selection, QoS assignment and traffic distribution" (RSQT). Our work contributes in four main areas. First, we formally define and solve a fully distributed problem version, which is very important for the management of a particular reconfigurable element. Second, we propose robust learning and adaptation, strategies for estimating (discovering) the performance potentials of alternate reconfigurations. Third, we give a computationally efficient solution to the problem of exploiting the performance potentials of reconfigurations and thus selecting the best ones. Finally, we present results that expose the behaviour and efficiency of our schemes
{"title":"Reconfigurations Selection in Cognitive, Beyond 3G, Radio Infrastructures","authors":"P. Demestichas, G. Dimitrakopoulos, K. Tsagkaris, K. Demestichas, Evgenia F. Adamopoulou","doi":"10.1109/CROWNCOM.2006.363468","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363468","url":null,"abstract":"B3G (beyond the 3rd generation) wireless infrastructures can be efficiently realized by exploiting cognitive networking concepts. Cognitive, wireless access, infrastructures can dynamically configure their transceivers with the appropriate radio access technologies (RATs) and spectrum, in order to, reactively or proactively, adapt to the environment requirements and conditions. Reconfiguration decisions call for advanced management functionality. This paper provides such management functionality by addressing a pertinent problem, called \"RAT and spectrum selection, QoS assignment and traffic distribution\" (RSQT). Our work contributes in four main areas. First, we formally define and solve a fully distributed problem version, which is very important for the management of a particular reconfigurable element. Second, we propose robust learning and adaptation, strategies for estimating (discovering) the performance potentials of alternate reconfigurations. Third, we give a computationally efficient solution to the problem of exploiting the performance potentials of reconfigurations and thus selecting the best ones. Finally, we present results that expose the behaviour and efficiency of our schemes","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127524000","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363476
T. Rondeau, B. Le, D. Maldonado, D. Scaperoth, C. Bostian
This paper approaches cognition on the physical and MAC layers by defining a common language of "knobs" and "meters" to discuss adaptation and learning. Cognitive radio merges artificial intelligence and software defined radios (SDR). It requires a simple language for communicating between these two levels. We define a method for doing this. We also discuss a genetic algorithm approach to perform intelligent radio adaptation, using the GNU radio platform as an example. We provide both conceptual and practical implementation details of a cognitive radio acting at the physical and MAC layers. Results presented show the promise for the genetic algorithm adaptation within the multi-objective optimization environment of the cognitive radio
{"title":"Cognitive Radio Formulation and Implementation","authors":"T. Rondeau, B. Le, D. Maldonado, D. Scaperoth, C. Bostian","doi":"10.1109/CROWNCOM.2006.363476","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363476","url":null,"abstract":"This paper approaches cognition on the physical and MAC layers by defining a common language of \"knobs\" and \"meters\" to discuss adaptation and learning. Cognitive radio merges artificial intelligence and software defined radios (SDR). It requires a simple language for communicating between these two levels. We define a method for doing this. We also discuss a genetic algorithm approach to perform intelligent radio adaptation, using the GNU radio platform as an example. We provide both conceptual and practical implementation details of a cognitive radio acting at the physical and MAC layers. Results presented show the promise for the genetic algorithm adaptation within the multi-objective optimization environment of the cognitive radio","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115751494","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363464
M. Nekovee
New trends and developments in radio technology together with current developments towards liberalization of spectrum management regulations are opening the opportunity to exploit the new paradigm of dynamic spectrum access (DSA). The key characteristic of DSA systems is their ability exploit knowledge of their electromagnetic environment to adapt their operation and access to spectrum. Their key promise is that they open the possibility of highly efficient (re)use of spectrum. The cognitive radio, built on software defined radio, is the intelligent, adaptive and frequency agile wireless device that will underlie most forms of DSA. In this paper we review proposed architectures for future DSA systems and describe some of the key research challenges associated with this new paradigm. Particular emphasize is given to autonomous cognitive radio DSA
{"title":"Dynamic Spectrum Access with Cognitive Radios: Future Architectures and Research Challenges","authors":"M. Nekovee","doi":"10.1109/CROWNCOM.2006.363464","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363464","url":null,"abstract":"New trends and developments in radio technology together with current developments towards liberalization of spectrum management regulations are opening the opportunity to exploit the new paradigm of dynamic spectrum access (DSA). The key characteristic of DSA systems is their ability exploit knowledge of their electromagnetic environment to adapt their operation and access to spectrum. Their key promise is that they open the possibility of highly efficient (re)use of spectrum. The cognitive radio, built on software defined radio, is the intelligent, adaptive and frequency agile wireless device that will underlie most forms of DSA. In this paper we review proposed architectures for future DSA systems and describe some of the key research challenges associated with this new paradigm. Particular emphasize is given to autonomous cognitive radio DSA","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125310651","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363454
Mohamed Ghozzi, F. Marx, M. Dohler, J. Palicot
The problem addressed in this paper is the test for presence of any telecommunication signal within a given frequency band, which is of great importance for cognitive radios. Since a telecommunication signal is well modeled as cyclostationary, we transform this problem to the one of testing for presence of the cylostationary property over a range of cyclic frequencies and we propose a constant false alarm rate (CFAR) multicycle detector based on a chi-squared (x2) statistical test of the time varying covariance estimate
{"title":"Cyclostatilonarilty-Based Test for Detection of Vacant Frequency Bands","authors":"Mohamed Ghozzi, F. Marx, M. Dohler, J. Palicot","doi":"10.1109/CROWNCOM.2006.363454","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363454","url":null,"abstract":"The problem addressed in this paper is the test for presence of any telecommunication signal within a given frequency band, which is of great importance for cognitive radios. Since a telecommunication signal is well modeled as cyclostationary, we transform this problem to the one of testing for presence of the cylostationary property over a range of cyclic frequencies and we propose a constant false alarm rate (CFAR) multicycle detector based on a chi-squared (x2) statistical test of the time varying covariance estimate","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130643456","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363447
L. Godard, C. Moy, J. Palicot
This paper proposes a functional management architecture for cognitive radio systems. It relies on a previously defined configuration management architecture for multi-standard SDR systems, and complement it to support cognitive radio features. This paper explains the requirements of cognitive radio systems in terms of reconfiguration, smartness and sensing capabilities. A configuration management architecture capable of dealing with the hardware heterogeneity and a wide range of reconfiguration scenarios expected with SDR systems is presented. The management is distributed over the system and a hierarchical dependency is set on 3 layers, each having a different level of knowledge of the system and the associated hardware constraints of the elements it supervises. Then a cognitive management functional architecture is derived from the previous one, copying the 3 layers of hierarchy. The roles of the elements of each layer are discussed, as well as their respective interactions and their relationships with the elements of the configuration management architecture
{"title":"From a Configuration Management to a Cognitive Radio Management of SDR Systems","authors":"L. Godard, C. Moy, J. Palicot","doi":"10.1109/CROWNCOM.2006.363447","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363447","url":null,"abstract":"This paper proposes a functional management architecture for cognitive radio systems. It relies on a previously defined configuration management architecture for multi-standard SDR systems, and complement it to support cognitive radio features. This paper explains the requirements of cognitive radio systems in terms of reconfiguration, smartness and sensing capabilities. A configuration management architecture capable of dealing with the hardware heterogeneity and a wide range of reconfiguration scenarios expected with SDR systems is presented. The management is distributed over the system and a hierarchical dependency is set on 3 layers, each having a different level of knowledge of the system and the associated hardware constraints of the elements it supervises. Then a cognitive management functional architecture is derived from the previous one, copying the 3 layers of hierarchy. The roles of the elements of each layer are discussed, as well as their respective interactions and their relationships with the elements of the configuration management architecture","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131459653","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363466
T. Banerjee, Chittabrata Ghosh, D. Agrawal
In a cellular communication scenario, wireless sensors can be deployed to sense the interference power of the frequency band. In an ideal channel, interference temperature (IT) which is directly proportional to the interference power can be assumed to vary spatially with the frequency of the sub channel. We propose a scheme for approximating ITs over an extended C-band (licensed and unused television band) by fitting sub channel frequencies and corresponding ITs to a regression model. Using this model, IT of a random sub channel can be calculated by the base station (BS) for further analysis of the channel interference. Our proposed model based on readings reported by sensors helps in dynamic channel selection (S-DCS) in extended C-band for assignment to unlicensed secondary users. S-DCS maximizes channel utilization and proves to be economic from energy consumption point of view. It also exhibits substantial amount of accuracy with error bound within 6.8%. Again, users are assigned empty sub channels without actually probing them, incurring minimum delay in the process. Overall channel allocation efficiency is also maximized along with fairness to individual users
{"title":"Wireless Sensor based Dynamic Channel Selection in Cellular Communication by Cognitive Radio Approach","authors":"T. Banerjee, Chittabrata Ghosh, D. Agrawal","doi":"10.1109/CROWNCOM.2006.363466","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363466","url":null,"abstract":"In a cellular communication scenario, wireless sensors can be deployed to sense the interference power of the frequency band. In an ideal channel, interference temperature (IT) which is directly proportional to the interference power can be assumed to vary spatially with the frequency of the sub channel. We propose a scheme for approximating ITs over an extended C-band (licensed and unused television band) by fitting sub channel frequencies and corresponding ITs to a regression model. Using this model, IT of a random sub channel can be calculated by the base station (BS) for further analysis of the channel interference. Our proposed model based on readings reported by sensors helps in dynamic channel selection (S-DCS) in extended C-band for assignment to unlicensed secondary users. S-DCS maximizes channel utilization and proves to be economic from energy consumption point of view. It also exhibits substantial amount of accuracy with error bound within 6.8%. Again, users are assigned empty sub channels without actually probing them, incurring minimum delay in the process. Overall channel allocation efficiency is also maximized along with fairness to individual users","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122445765","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 : 2006-06-08DOI: 10.1109/CROWNCOM.2006.363467
P. Sutton, L. Doyle, K. Nolan
By introducing self-awareness and computational intelligence to reconfigurable radio networks, cognitive networks are viewed as the key to a new generation of self-configuring, self-optimizing and self-healing communications systems. However, in order to make such systems realizable, a paradigm shift in the design of network node architectures is required. This paper presents a reconfigurable platform based on an architecture specifically designed for nodes within a cognitive network
{"title":"A Reconfigurable Platform for Cognitive Networks","authors":"P. Sutton, L. Doyle, K. Nolan","doi":"10.1109/CROWNCOM.2006.363467","DOIUrl":"https://doi.org/10.1109/CROWNCOM.2006.363467","url":null,"abstract":"By introducing self-awareness and computational intelligence to reconfigurable radio networks, cognitive networks are viewed as the key to a new generation of self-configuring, self-optimizing and self-healing communications systems. However, in order to make such systems realizable, a paradigm shift in the design of network node architectures is required. This paper presents a reconfigurable platform based on an architecture specifically designed for nodes within a cognitive network","PeriodicalId":422961,"journal":{"name":"2006 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125838218","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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