Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850275
W. Lintz, J. McEachen, D. Jenn
A model is proposed to describe expected communications performance between two sensor network nodes where both are unsteady in physical orientation with respect to a specified reference. Model application enables determination of transmit power in terms of a preferred link performance probability. Increasing applications of wireless sensor networks has proportionally increased fielding ideas and platforms. The stability of a platform for a sensor network node cannot always be assumed stable due to physical variation from motion or surface conditions. This creates a time-varying random orientation between nodes in communication with an adjacent partner. A stochastic model is proposed connecting the physical random orientation of a pair of elements to their transmission components. The resulting performance of a link using the proposed model is then applied to achieve reliable communications performance. Analysis demonstrates improved use of network power compared to a method which assigns a blanket power margin across the network.
{"title":"Sensor network pair-wise wireless communications performance with unsteady node orientation","authors":"W. Lintz, J. McEachen, D. Jenn","doi":"10.1109/SARNOF.2009.4850275","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850275","url":null,"abstract":"A model is proposed to describe expected communications performance between two sensor network nodes where both are unsteady in physical orientation with respect to a specified reference. Model application enables determination of transmit power in terms of a preferred link performance probability. Increasing applications of wireless sensor networks has proportionally increased fielding ideas and platforms. The stability of a platform for a sensor network node cannot always be assumed stable due to physical variation from motion or surface conditions. This creates a time-varying random orientation between nodes in communication with an adjacent partner. A stochastic model is proposed connecting the physical random orientation of a pair of elements to their transmission components. The resulting performance of a link using the proposed model is then applied to achieve reliable communications performance. Analysis demonstrates improved use of network power compared to a method which assigns a blanket power margin across the network.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134052999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850299
Bai Zhang, Zhiwei Mao
Two novel packet scheduling algorithms, the basic and modified priority and fairness (BPF and MPF)-based packet scheduling algorithms, are proposed in this paper for adaptive modulation and coding (AMC)-based orthogonal frequency division multiple access (OFDMA) systems. In the proposed algorithms, various user traffics are transmitted in a sequence determined by their priorities on subchannels while jointly considering fairness among users and subchannels. Simulation results show that the proposed algorithms increase the number of supported users satisfying the same underlying quality of service (QoS) requirements than some existing packet scheduling algorithms in literature.
{"title":"BPF and MPF-based packet scheduling for AMC-based OFDMA wireless communication systems","authors":"Bai Zhang, Zhiwei Mao","doi":"10.1109/SARNOF.2009.4850299","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850299","url":null,"abstract":"Two novel packet scheduling algorithms, the basic and modified priority and fairness (BPF and MPF)-based packet scheduling algorithms, are proposed in this paper for adaptive modulation and coding (AMC)-based orthogonal frequency division multiple access (OFDMA) systems. In the proposed algorithms, various user traffics are transmitted in a sequence determined by their priorities on subchannels while jointly considering fairness among users and subchannels. Simulation results show that the proposed algorithms increase the number of supported users satisfying the same underlying quality of service (QoS) requirements than some existing packet scheduling algorithms in literature.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"358 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115866512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850360
Sattar Hussain, A. S. Zahmati, Xavier N Fernando
The wide range of wireless sensor network (WSN) applications makes it necessary to design MAC protocols that not only save energy and extend network life, but also improve network throughput, bandwidth utilization, and latency performance. In this paper we propose LASA (Low-energy Adaptive Slot Allocation) to replace the fix slot size in classical Time Division Multiple Access (TDMA) schemes by a variable slot size that dynamically adapts to the data size generated at sensor nodes. The proposed scheme eliminates slot idle time when nodes remain unnecessarily active with no data to transmit or receive. This approach outperforms the static slot size TDMA scheme, especially when there is a high traffic fluctuation and a big variance in the sensor data length. Our results show that this scheme significantly enhances network throughput, reduces bandwidth utilization, saves energy and extends network lifetime.
{"title":"LASA: Low-energy adaptive slot allocation scheduling algorithm for wireless sensor networks","authors":"Sattar Hussain, A. S. Zahmati, Xavier N Fernando","doi":"10.1109/SARNOF.2009.4850360","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850360","url":null,"abstract":"The wide range of wireless sensor network (WSN) applications makes it necessary to design MAC protocols that not only save energy and extend network life, but also improve network throughput, bandwidth utilization, and latency performance. In this paper we propose LASA (Low-energy Adaptive Slot Allocation) to replace the fix slot size in classical Time Division Multiple Access (TDMA) schemes by a variable slot size that dynamically adapts to the data size generated at sensor nodes. The proposed scheme eliminates slot idle time when nodes remain unnecessarily active with no data to transmit or receive. This approach outperforms the static slot size TDMA scheme, especially when there is a high traffic fluctuation and a big variance in the sensor data length. Our results show that this scheme significantly enhances network throughput, reduces bandwidth utilization, saves energy and extends network lifetime.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114173248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850339
A. Prescod, B. Dingel, N. Madamopoulos
In previous reports, we introduced a new lumped electrode-based optical modulator design with superior linearity (Spurious Free Dynamic Range, SFDR ∼ 133 dB at 1Hz bandwidth), and wider linearization bandwidth, when compared with previously reported Resonator-Assisted Mach Zehnder (RAMZ) modulators. Here, we extend the modulator design to a traveling wave (TW) electrode design that produces significant bandwidth improvement capability while maintaining the excellent SFDR (≪130 dB at 1Hz bandwidth). Furthermore, we utilize the combination of externally controlled parameters such as the RF split ratio and RF phase control, for maximum design flexibility and parameter optimization control.
{"title":"Traveling wave optical modulator with high dynamic range (≪130 dB) at large modulation frequencies","authors":"A. Prescod, B. Dingel, N. Madamopoulos","doi":"10.1109/SARNOF.2009.4850339","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850339","url":null,"abstract":"In previous reports, we introduced a new lumped electrode-based optical modulator design with superior linearity (Spurious Free Dynamic Range, SFDR ∼ 133 dB at 1Hz bandwidth), and wider linearization bandwidth, when compared with previously reported Resonator-Assisted Mach Zehnder (RAMZ) modulators. Here, we extend the modulator design to a traveling wave (TW) electrode design that produces significant bandwidth improvement capability while maintaining the excellent SFDR (≪130 dB at 1Hz bandwidth). Furthermore, we utilize the combination of externally controlled parameters such as the RF split ratio and RF phase control, for maximum design flexibility and parameter optimization control.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115333580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850313
An-Ni Shen, Song Guo, H. Chien
Many applications of wireless sensor network (WSN) require secure data communications, especially in a hostile environment. In order to protect the sensitive data and the sensor readings, secret keys should be used to encrypt the exchanged messages between communicating nodes. Traditional asymmetric key cryptosystems are infeasible in WSNs due to the low capacity of each senor node. In this paper, we propose a new key pre-distribution scheme for hierarchical WSNs. Compared to some of the existing schemes, our methods possess the following features that are particularly beneficial to the resource-constrained large-scale WSNs: (1) it can fully defend against the node captured attack, (2) it minimizes the storage and communication overhead, and (3) it provides full connectivity of the network.
{"title":"An efficient and scalable key distribution mechanism for hierarchical wireless sensor networks","authors":"An-Ni Shen, Song Guo, H. Chien","doi":"10.1109/SARNOF.2009.4850313","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850313","url":null,"abstract":"Many applications of wireless sensor network (WSN) require secure data communications, especially in a hostile environment. In order to protect the sensitive data and the sensor readings, secret keys should be used to encrypt the exchanged messages between communicating nodes. Traditional asymmetric key cryptosystems are infeasible in WSNs due to the low capacity of each senor node. In this paper, we propose a new key pre-distribution scheme for hierarchical WSNs. Compared to some of the existing schemes, our methods possess the following features that are particularly beneficial to the resource-constrained large-scale WSNs: (1) it can fully defend against the node captured attack, (2) it minimizes the storage and communication overhead, and (3) it provides full connectivity of the network.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116177091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850369
K. Ho, C. Vaz, D. G. Daut
In this study, a wavelet transform-based technique is used in an Automatic Modulation Recognition (AMR) process to classify different types of digitally modulated binary signals. The communications signals considered are Binary Amplitude Shift Keyed (BASK), Binary Frequency Shift Keyed (BFSK), and Binary Phase Shift Keyed (BPSK) signals, which are transmitted over an Additive White Gaussian Noise (AWGN) channel having a Signal-to-Noise Ratio (SNR) in the range from −5 dB to 10 dB. The distinguishing features of these three modulation schemes arise due to variations of amplitude, frequency and phase of a carrier signal. The different types of binary communications signals are analyzed using the Continuous Wavelet Transform (CWT). The unique features of each modulation type are extracted from the specific wavelet-domain representation of the respective signals. The features are stored as templates within the receiver and used for the purpose of classifying the signal according to modulation type. The wavelet used for template construction and the decomposition of received signals is the Reverse Biorthogonal Spline 1.3 (rbio1.3) wavelet. It has been determined via extensive computer simulations that the rate of correct classification for BASK signals is 100% and for BPSK signals is 99.7% over the range of SNR values considered. The rates of correct classification for BFSK signals are 99.6%, 98.7%, 94.0%, and 54.0% for SNR = 10 dB, 5 dB, 0 dB, and −5 dB, respectively. The AMR process presented in this study generally produces higher rates of correct classification than other AMR techniques available in the literature. This observation is especially significant when considering the cases of BASK and BPSK for systems operating at an SNR value of −5 dB.
{"title":"A wavelet-based method for classification of binary digitally modulated signals","authors":"K. Ho, C. Vaz, D. G. Daut","doi":"10.1109/SARNOF.2009.4850369","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850369","url":null,"abstract":"In this study, a wavelet transform-based technique is used in an Automatic Modulation Recognition (AMR) process to classify different types of digitally modulated binary signals. The communications signals considered are Binary Amplitude Shift Keyed (BASK), Binary Frequency Shift Keyed (BFSK), and Binary Phase Shift Keyed (BPSK) signals, which are transmitted over an Additive White Gaussian Noise (AWGN) channel having a Signal-to-Noise Ratio (SNR) in the range from −5 dB to 10 dB. The distinguishing features of these three modulation schemes arise due to variations of amplitude, frequency and phase of a carrier signal. The different types of binary communications signals are analyzed using the Continuous Wavelet Transform (CWT). The unique features of each modulation type are extracted from the specific wavelet-domain representation of the respective signals. The features are stored as templates within the receiver and used for the purpose of classifying the signal according to modulation type. The wavelet used for template construction and the decomposition of received signals is the Reverse Biorthogonal Spline 1.3 (rbio1.3) wavelet. It has been determined via extensive computer simulations that the rate of correct classification for BASK signals is 100% and for BPSK signals is 99.7% over the range of SNR values considered. The rates of correct classification for BFSK signals are 99.6%, 98.7%, 94.0%, and 54.0% for SNR = 10 dB, 5 dB, 0 dB, and −5 dB, respectively. The AMR process presented in this study generally produces higher rates of correct classification than other AMR techniques available in the literature. This observation is especially significant when considering the cases of BASK and BPSK for systems operating at an SNR value of −5 dB.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114701549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850314
Yuanqiu Luo, F. Effenberger, Bo Gao
In this paper, a mechanism of the transmission convergence (TC) layer framing in XG-PON1 is proposed. It enhances the existing G-PON TC (GTC) protocol system by employing the concept of word alignment. The major benefits include simplified design, extended support to more users, and easy implementation. Performance comparison with the existing GTC shows the efficiency improvement of the proposed word-aligned framing mechanism in various scenarios of the next generation optical access networks.
{"title":"Transmission convergence layer framing in XG-PON1","authors":"Yuanqiu Luo, F. Effenberger, Bo Gao","doi":"10.1109/SARNOF.2009.4850314","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850314","url":null,"abstract":"In this paper, a mechanism of the transmission convergence (TC) layer framing in XG-PON1 is proposed. It enhances the existing G-PON TC (GTC) protocol system by employing the concept of word alignment. The major benefits include simplified design, extended support to more users, and easy implementation. Performance comparison with the existing GTC shows the efficiency improvement of the proposed word-aligned framing mechanism in various scenarios of the next generation optical access networks.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125898911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850291
Di Zheng, Yu-dong Yao
Time division multiple access (TDMA) is suitable for the energy efficiency requirement of wireless sensor networks (WSN) since it avoids idle listening and collisions. We introduce a two-tier-TDMA structure to describe and analyze a TDMA-based convergecast WSN. In our model, each cluster head is responsible for forwarding data from ordinary nodes of its cluster to a super cluster head. This paper presents derivations and simulations of the two-tier TDMA performance in terms of throughput. We consider scenarios with different cluster sizes, signal fading and inter-cluster interference.
{"title":"Throughput performance evaluation of two-tier TDMA for sensor networks","authors":"Di Zheng, Yu-dong Yao","doi":"10.1109/SARNOF.2009.4850291","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850291","url":null,"abstract":"Time division multiple access (TDMA) is suitable for the energy efficiency requirement of wireless sensor networks (WSN) since it avoids idle listening and collisions. We introduce a two-tier-TDMA structure to describe and analyze a TDMA-based convergecast WSN. In our model, each cluster head is responsible for forwarding data from ordinary nodes of its cluster to a super cluster head. This paper presents derivations and simulations of the two-tier TDMA performance in terms of throughput. We consider scenarios with different cluster sizes, signal fading and inter-cluster interference.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125136415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850366
William A. Ling, P. Sotiriadis
This work presents a compact, almost-digital frequency mixer that produces a sinusoidal signal at frequency ω1±ω2 when driven by two digital periodic signals of frequencies ω1 and ω2. The mixer uses multiple phases of the input signals to suppress higher order intermodulation products and increase the spurious free dynamic range of the output. A circuit implementation has been realized using an FPGA and it was used to derive spectral measurements demonstrating the feasibility and performance of the architecture.
{"title":"Almost-digital multiphase frequency mixing","authors":"William A. Ling, P. Sotiriadis","doi":"10.1109/SARNOF.2009.4850366","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850366","url":null,"abstract":"This work presents a compact, almost-digital frequency mixer that produces a sinusoidal signal at frequency ω<inf>1</inf>±ω<inf>2</inf> when driven by two digital periodic signals of frequencies ω<inf>1</inf> and ω<inf>2</inf>. The mixer uses multiple phases of the input signals to suppress higher order intermodulation products and increase the spurious free dynamic range of the output. A circuit implementation has been realized using an FPGA and it was used to derive spectral measurements demonstrating the feasibility and performance of the architecture.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122097591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-03-30DOI: 10.1109/SARNOF.2009.4850316
A. A. Ajibesin, H. Chan, M. Kah
An enhanced adaptive scheme based on threshold method with a reduced complexity that combine adaptive modulation and coding with diversity combining is presented for throughput maximization in broadband code division multiple access (CDMA) satellite networks. The proposed algorithm is a modify, enhanced, and more robust version of the existing algorithms for adaptive transmission rate and modulation in CDMA networks. The rate compatible punctured turbo-coded (RCPT), which has been found to give improved throughput performance in a direct sequence (DS) CDMA is exploited. A semi-analytical process and simulations were carried out. It is found that there are significant improvement in the average throughput and the bit-error performance. The proposed algorithm using adaptive coding and modulation (instead of variable spreading gain) outperforms other systems such as Selective Power Control with Active Link Protection (SPC-ALP) algorithm proposed for adaptive transmission rate and power control in CDMA networks.
{"title":"Throughput enhancement of joint AMC and power control with diversity combining for next generation mobile satellite systems","authors":"A. A. Ajibesin, H. Chan, M. Kah","doi":"10.1109/SARNOF.2009.4850316","DOIUrl":"https://doi.org/10.1109/SARNOF.2009.4850316","url":null,"abstract":"An enhanced adaptive scheme based on threshold method with a reduced complexity that combine adaptive modulation and coding with diversity combining is presented for throughput maximization in broadband code division multiple access (CDMA) satellite networks. The proposed algorithm is a modify, enhanced, and more robust version of the existing algorithms for adaptive transmission rate and modulation in CDMA networks. The rate compatible punctured turbo-coded (RCPT), which has been found to give improved throughput performance in a direct sequence (DS) CDMA is exploited. A semi-analytical process and simulations were carried out. It is found that there are significant improvement in the average throughput and the bit-error performance. The proposed algorithm using adaptive coding and modulation (instead of variable spreading gain) outperforms other systems such as Selective Power Control with Active Link Protection (SPC-ALP) algorithm proposed for adaptive transmission rate and power control in CDMA networks.","PeriodicalId":230233,"journal":{"name":"2009 IEEE Sarnoff Symposium","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123297138","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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