Pub Date : 2006-04-10DOI: 10.1109/ISWPC.2006.1613603
Haitao Liu, Hanbing Zhou, Daoben Li
In this paper, we study the error performance of Vertical Bell Labs Layered Space-Time (V-BLAST) using maximum likelihood (ML) receiver in the presence of receive correlated fading channel. The squared Euclidean distance is observed to be weighted Chi-square distributed random variable. Based on the observation, we present a new exact expression of the pairwise error probability (PEP) and the union bound of the BER. The asymptotic result is used to quantify the loss of the diversity order and the penalty of SNR. It is shown the loss of diversity order equals to the difference of the number of receiver antennas and the rank of receive correlation matrix, and, in the case of full rank of correlation matrix, the penalty of SNR is determined by the determinant of the receive correlation matrix. Simulation results are given to corroborate the theoretical analysis.
{"title":"Impact of receive correlation on the performance of V-BLAST system","authors":"Haitao Liu, Hanbing Zhou, Daoben Li","doi":"10.1109/ISWPC.2006.1613603","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613603","url":null,"abstract":"In this paper, we study the error performance of Vertical Bell Labs Layered Space-Time (V-BLAST) using maximum likelihood (ML) receiver in the presence of receive correlated fading channel. The squared Euclidean distance is observed to be weighted Chi-square distributed random variable. Based on the observation, we present a new exact expression of the pairwise error probability (PEP) and the union bound of the BER. The asymptotic result is used to quantify the loss of the diversity order and the penalty of SNR. It is shown the loss of diversity order equals to the difference of the number of receiver antennas and the rank of receive correlation matrix, and, in the case of full rank of correlation matrix, the penalty of SNR is determined by the determinant of the receive correlation matrix. Simulation results are given to corroborate the theoretical analysis.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125298249","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613567
W. H. Wan Hassan, S. Khatun
Despite of the many advantages of OFDM, it has two main drawbacks which are high peak to average power ratio (PAPR) and synchronization problem. High PAPR causes saturation in power amplifiers, leading to intermodulation products among the sub carriers and disturbing out of band energy. Therefore, it is desirable to reduce the PAPR by means of PAPR reduction schemes. However, it caused the degradation of BER and enhanced the growth of out of band radiation which has led to the degradation of OFDM overall performance. In this paper, OFDM system with an enhanced clipping technique has been proposed, the effects of clipping have been analyzed and the system is evaluated by integrating with its significant features including convolutional forward error control coding, oversampled inverse fast Fourier transform (IFFT) and digital filtering technique in order to minimize the effects of clipping. It is shown that the bit error rate (BER) of the clipped OFDM signal is improved, the PAPR is further reduced and the effect of out of band radiation is minimized. Besides, other effects of the filtering technique are also analyzed in order to optimize the overall performance of our proposed system.
{"title":"Effects of digital filtering technique in reducing the effects of clipping of an enhanced orthogonal frequency division multiplexing system","authors":"W. H. Wan Hassan, S. Khatun","doi":"10.1109/ISWPC.2006.1613567","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613567","url":null,"abstract":"Despite of the many advantages of OFDM, it has two main drawbacks which are high peak to average power ratio (PAPR) and synchronization problem. High PAPR causes saturation in power amplifiers, leading to intermodulation products among the sub carriers and disturbing out of band energy. Therefore, it is desirable to reduce the PAPR by means of PAPR reduction schemes. However, it caused the degradation of BER and enhanced the growth of out of band radiation which has led to the degradation of OFDM overall performance. In this paper, OFDM system with an enhanced clipping technique has been proposed, the effects of clipping have been analyzed and the system is evaluated by integrating with its significant features including convolutional forward error control coding, oversampled inverse fast Fourier transform (IFFT) and digital filtering technique in order to minimize the effects of clipping. It is shown that the bit error rate (BER) of the clipped OFDM signal is improved, the PAPR is further reduced and the effect of out of band radiation is minimized. Besides, other effects of the filtering technique are also analyzed in order to optimize the overall performance of our proposed system.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113986234","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613636
P. Keeratiwintakorn, P. Krishnamurthy
Due to broadcast nature of wireless radio transmission, security services are of paramount importance to protect information exchanged in a wireless network. However, providing security services increases the computation and hence energy consumption due to cryptographic algorithms. Energy tends to be a very limited resource for wireless devices operating on battery. Thus, energy efficient security services are necessary to operate limited wireless devices securely. In this paper, we propose Tunable Security Model (TSM) to minimize energy consumption while providing security services such that the user's security level requirement is satisfied. From our experiments in IEEE 802.11 wireless networks, it is shown that using TSM can save up to 8% energy for low-level security, and up to 43% energy for high-level security.
{"title":"Energy Efficient Security Services for Limited Wireless Devices","authors":"P. Keeratiwintakorn, P. Krishnamurthy","doi":"10.1109/ISWPC.2006.1613636","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613636","url":null,"abstract":"Due to broadcast nature of wireless radio transmission, security services are of paramount importance to protect information exchanged in a wireless network. However, providing security services increases the computation and hence energy consumption due to cryptographic algorithms. Energy tends to be a very limited resource for wireless devices operating on battery. Thus, energy efficient security services are necessary to operate limited wireless devices securely. In this paper, we propose Tunable Security Model (TSM) to minimize energy consumption while providing security services such that the user's security level requirement is satisfied. From our experiments in IEEE 802.11 wireless networks, it is shown that using TSM can save up to 8% energy for low-level security, and up to 43% energy for high-level security.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128534264","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613598
F. Izquierdo, M. Ciurana, F. Barceló, J. Paradells, E. Zola
Nowadays, several systems are available for outdoor localization, such as GPS, assisted GPS and other systems working on cellular networks. However, there is no proper location system for indoor scenarios. Research into designing location systems for 802.11 networks is being carried out, so locating mobile devices on global networks (GSM/cellular + GPS + WLAN) finally seems feasible. The technique presented in this paper uses existing wireless LAN infrastructure with minor changes to provide an accurate estimation of the location of mobile devices in indoor environments. This technique is based on round-trip time (RTT) measurements, which are used to estimate distances between the device to be located and WLAN access points. Each RTT measurement estimates the time elapsed between the RTS (Request-to-Send) and the CTS (Clear-to-Send) frame of the 802.11 standard. By applying trilateration algorithms, an accurate estimation of the mobile position is calculated.
{"title":"Performance evaluation of a TOA-based trilateration method to locate terminals in WLAN","authors":"F. Izquierdo, M. Ciurana, F. Barceló, J. Paradells, E. Zola","doi":"10.1109/ISWPC.2006.1613598","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613598","url":null,"abstract":"Nowadays, several systems are available for outdoor localization, such as GPS, assisted GPS and other systems working on cellular networks. However, there is no proper location system for indoor scenarios. Research into designing location systems for 802.11 networks is being carried out, so locating mobile devices on global networks (GSM/cellular + GPS + WLAN) finally seems feasible. The technique presented in this paper uses existing wireless LAN infrastructure with minor changes to provide an accurate estimation of the location of mobile devices in indoor environments. This technique is based on round-trip time (RTT) measurements, which are used to estimate distances between the device to be located and WLAN access points. Each RTT measurement estimates the time elapsed between the RTS (Request-to-Send) and the CTS (Clear-to-Send) frame of the 802.11 standard. By applying trilateration algorithms, an accurate estimation of the mobile position is calculated.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115584604","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613614
Nin-Jain Shin, T. Wu, Wei-Ming Chen, H. Chao
In the development of wireless cellular network, there are some different focuses. As far as these focuses are concerned, the wireless and cellular network works with different bandwidth and radio frequency. Also, the next generation cellular network must have important services, for example, the media service. To use the media service, we need stable bandwidth and bundle delay time because in 3G cellular network, the IP handoff problem may come from the faster speed than that in wireless network. Therefore, we propose QoS architecture to provide bandwidth, to lower handoff problem and to increase the bandwidth utilization.
{"title":"Using MPLS-based dynamic tunnel for location control and QoS management in wireless network","authors":"Nin-Jain Shin, T. Wu, Wei-Ming Chen, H. Chao","doi":"10.1109/ISWPC.2006.1613614","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613614","url":null,"abstract":"In the development of wireless cellular network, there are some different focuses. As far as these focuses are concerned, the wireless and cellular network works with different bandwidth and radio frequency. Also, the next generation cellular network must have important services, for example, the media service. To use the media service, we need stable bandwidth and bundle delay time because in 3G cellular network, the IP handoff problem may come from the faster speed than that in wireless network. Therefore, we propose QoS architecture to provide bandwidth, to lower handoff problem and to increase the bandwidth utilization.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125728664","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613653
M. Watfa, S. Commuri
Sensor networks are becoming increasingly important as tools for monitoring remote environments. Networking together hundreds or thousands of inexpensive sensor nodes allows users to accurately monitor a remote environment by intelligently combining the data from the individual nodes. In this paper, contrary to existing techniques, the deployment and coverage problems in a three dimensional space are studied. A solution to the problem of optimal node 3D placement and algorithms for minimizing the number of active nodes while covering a region are presented. The minimum number of nodes will serve as optimality measures for coverage in three dimensional space.
{"title":"Optimality measures for coverage in 3D wireless sensor networks","authors":"M. Watfa, S. Commuri","doi":"10.1109/ISWPC.2006.1613653","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613653","url":null,"abstract":"Sensor networks are becoming increasingly important as tools for monitoring remote environments. Networking together hundreds or thousands of inexpensive sensor nodes allows users to accurately monitor a remote environment by intelligently combining the data from the individual nodes. In this paper, contrary to existing techniques, the deployment and coverage problems in a three dimensional space are studied. A solution to the problem of optimal node 3D placement and algorithms for minimizing the number of active nodes while covering a region are presented. The minimum number of nodes will serve as optimality measures for coverage in three dimensional space.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128152246","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613597
Y. H. Ho, A. H. Ho, K. Hua, T. Do
Most of today's communication techniques for mobile ad hoc networks take a connection-oriented approach. Mobile nodes need to discover routes and establish a connection before they can communicate. This strategy is not robust as it cannot adapt to frequent unpredictable topology changes due to high mobility. Constant reconnections incur significant overhead making these schemes unsuitable for applications such as voice and video. To address these issues, we explore a connectionless paradigm in this paper. We leverage technology such as GPS (Global Positioning System) to allow a source node to discover its general direction with respect to a destination node. Data packets are relayed along this directional path toward the destination using different intermediate nodes at different times without having to first establish a connection. Although an earlier work called connectionless approach (CLA) to mobile ad hoc network can work well in high mobility environment, it cannot be applied directly to obstacle environments because obstacle (i.e., mountains, lakes, or buildings) often block direct path between any two nodes. The contribution of this paper is to adapt CLA to obstacle environments. The proposed approach can relay data around obstacles, can quickly adapt to topology change, and can provide multiple communicating paths to the destination.
{"title":"Adapting connectionless approach to mobile ad hoc networks in obstacle environment","authors":"Y. H. Ho, A. H. Ho, K. Hua, T. Do","doi":"10.1109/ISWPC.2006.1613597","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613597","url":null,"abstract":"Most of today's communication techniques for mobile ad hoc networks take a connection-oriented approach. Mobile nodes need to discover routes and establish a connection before they can communicate. This strategy is not robust as it cannot adapt to frequent unpredictable topology changes due to high mobility. Constant reconnections incur significant overhead making these schemes unsuitable for applications such as voice and video. To address these issues, we explore a connectionless paradigm in this paper. We leverage technology such as GPS (Global Positioning System) to allow a source node to discover its general direction with respect to a destination node. Data packets are relayed along this directional path toward the destination using different intermediate nodes at different times without having to first establish a connection. Although an earlier work called connectionless approach (CLA) to mobile ad hoc network can work well in high mobility environment, it cannot be applied directly to obstacle environments because obstacle (i.e., mountains, lakes, or buildings) often block direct path between any two nodes. The contribution of this paper is to adapt CLA to obstacle environments. The proposed approach can relay data around obstacles, can quickly adapt to topology change, and can provide multiple communicating paths to the destination.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124245218","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613619
Namhi Kang, L. Lo Iacono, C. Rulan, Younghan Kim
Modern wireless networks allow a mobile node including smart devices or sensing devices to communicate with each other regardless of the time it wishes to access and the place where it is. Moreover the current wireless network technologies are trying to offer high data rates with low error rates. This is especially important for so called field workers, who work outside a company's building or even a fixed location but have to access the corporate LAN. VPNs enable corporations to extend services to mobile employees and partners without the risk of compromising their existing security standards. A mobile VPN (MVPN) extends the VPN to mobile workers who establish an VPN tunnel over the Internet using wireless connections such as GSM, GPRS, WLAN or UMTS. The security mechanisms integrated into the VPN technology cause a considerable data size expansion which is especially in wireless networks undesirable. In this paper we present a mechanism that enables the application of header compression techniques in IPsec secured VPNs which as a result reduces data size expansion and consequently the packet-loss rate and transmission costs.
{"title":"Efficient application of IPsec VPNs in wireless networks","authors":"Namhi Kang, L. Lo Iacono, C. Rulan, Younghan Kim","doi":"10.1109/ISWPC.2006.1613619","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613619","url":null,"abstract":"Modern wireless networks allow a mobile node including smart devices or sensing devices to communicate with each other regardless of the time it wishes to access and the place where it is. Moreover the current wireless network technologies are trying to offer high data rates with low error rates. This is especially important for so called field workers, who work outside a company's building or even a fixed location but have to access the corporate LAN. VPNs enable corporations to extend services to mobile employees and partners without the risk of compromising their existing security standards. A mobile VPN (MVPN) extends the VPN to mobile workers who establish an VPN tunnel over the Internet using wireless connections such as GSM, GPRS, WLAN or UMTS. The security mechanisms integrated into the VPN technology cause a considerable data size expansion which is especially in wireless networks undesirable. In this paper we present a mechanism that enables the application of header compression techniques in IPsec secured VPNs which as a result reduces data size expansion and consequently the packet-loss rate and transmission costs.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131634478","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613580
S. Phaiboon, S. Somkuarnpanit
This paper presents studies of propagation in a suburban forest based on a measurement campaign at a frequency of 1.8 GHz. We investigated how tree density affected path loss-distance and the fast fading characteristic depending on the base tree size and base station antenna height in a range of 3, 4, and 5 m above ground while the receiving antenna height was fixed at 1.8 m above ground. The path loss exponent is found that to average 3.8, 3.7 and 2.2 for the measurement areas of high, medium, and low densities respectively. The high density area with low tree heights provides maximum path loss exponents. Path loss in the same density area depends on the number of trees in the direct path between the transmitter and the receiver. The measurement of signal variation shows that a multi-path contribution becomes more significant as the base station antenna is raised.
{"title":"Mobile path loss characteristics for low base station antenna height in different forest densities","authors":"S. Phaiboon, S. Somkuarnpanit","doi":"10.1109/ISWPC.2006.1613580","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613580","url":null,"abstract":"This paper presents studies of propagation in a suburban forest based on a measurement campaign at a frequency of 1.8 GHz. We investigated how tree density affected path loss-distance and the fast fading characteristic depending on the base tree size and base station antenna height in a range of 3, 4, and 5 m above ground while the receiving antenna height was fixed at 1.8 m above ground. The path loss exponent is found that to average 3.8, 3.7 and 2.2 for the measurement areas of high, medium, and low densities respectively. The high density area with low tree heights provides maximum path loss exponents. Path loss in the same density area depends on the number of trees in the direct path between the transmitter and the receiver. The measurement of signal variation shows that a multi-path contribution becomes more significant as the base station antenna is raised.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130451577","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 : 2006-04-10DOI: 10.1109/ISWPC.2006.1613622
M. Raina, Subhas Ghosh, R. Patro, G. Viswanath, Chadrashekhar T Honeywell
A scheme is proposed for secure data aggregation in wireless sensor networks. Commitment schemes and a class of functions called quasi commutative functions are used to achieve provably secure data aggregation. Efficient schemes to verify the data aggregation are provided.
{"title":"Secure data aggregation using commitment schemes and quasi commutative functions","authors":"M. Raina, Subhas Ghosh, R. Patro, G. Viswanath, Chadrashekhar T Honeywell","doi":"10.1109/ISWPC.2006.1613622","DOIUrl":"https://doi.org/10.1109/ISWPC.2006.1613622","url":null,"abstract":"A scheme is proposed for secure data aggregation in wireless sensor networks. Commitment schemes and a class of functions called quasi commutative functions are used to achieve provably secure data aggregation. Efficient schemes to verify the data aggregation are provided.","PeriodicalId":145728,"journal":{"name":"2006 1st International Symposium on Wireless Pervasive Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114416847","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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