Pub Date : 2008-03-05DOI: 10.1109/RWS.2008.4463518
S. Bensmida, O. Hammi, F. Ghannouchi
In this paper, a high efficiency GaN based power amplifier is designed using multi-harmonics load pull measurements. A load matching network that independently controls the load impedance at the fundamental, second and third harmonic frequencies is used for straightforward implementation. The continuously driven single-ended deep class AB biased power amplifier achieves a peak power added efficiency of 68% at saturation. It is found that the designed power amplifier exhibit highly non linear characteristics with 7 dB gain compression at saturation. Digital predistortion based linearizer is used to improve the linearity performance of the power amplifier under a WCDMA excitation (PAPR=9.8 dB). At a 10 dB output power back-off, 21% power added efficiency was measured along with 53 dBc adjacent channel leakage ratio.
{"title":"High efficiency digitally linearized GaN based power amplifier for 3G applications","authors":"S. Bensmida, O. Hammi, F. Ghannouchi","doi":"10.1109/RWS.2008.4463518","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463518","url":null,"abstract":"In this paper, a high efficiency GaN based power amplifier is designed using multi-harmonics load pull measurements. A load matching network that independently controls the load impedance at the fundamental, second and third harmonic frequencies is used for straightforward implementation. The continuously driven single-ended deep class AB biased power amplifier achieves a peak power added efficiency of 68% at saturation. It is found that the designed power amplifier exhibit highly non linear characteristics with 7 dB gain compression at saturation. Digital predistortion based linearizer is used to improve the linearity performance of the power amplifier under a WCDMA excitation (PAPR=9.8 dB). At a 10 dB output power back-off, 21% power added efficiency was measured along with 53 dBc adjacent channel leakage ratio.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"163 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122504914","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463624
C. Cook
This article illustrates the performance benefits to a cellular network of the introduction and integration of an underlain relay network. These relay elements are designed to operate in the service providers' licensed spectrum and provide a significant load balancing function between cells while increasing coverage restricted by shadowing and building penetration. The analysis is based on a mobile traffic simulation program developed by the author, which characterizes call blocking, call drops, handoffs and overhead messaging loads. The underlying relay elements are wirelessly integrated into the network. Both the underlying relay network and the Macro network are modeled with a number of dedicated voice channels. The number of voice channels allocated for each cell and relay is kept constant across the simulated, 19 cell, cluster and these allocations are varied between simulation runs for the design analysis curves.
{"title":"Performance simulation of a wireless relay network","authors":"C. Cook","doi":"10.1109/RWS.2008.4463624","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463624","url":null,"abstract":"This article illustrates the performance benefits to a cellular network of the introduction and integration of an underlain relay network. These relay elements are designed to operate in the service providers' licensed spectrum and provide a significant load balancing function between cells while increasing coverage restricted by shadowing and building penetration. The analysis is based on a mobile traffic simulation program developed by the author, which characterizes call blocking, call drops, handoffs and overhead messaging loads. The underlying relay elements are wirelessly integrated into the network. Both the underlying relay network and the Macro network are modeled with a number of dedicated voice channels. The number of voice channels allocated for each cell and relay is kept constant across the simulated, 19 cell, cluster and these allocations are varied between simulation runs for the design analysis curves.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128097348","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463479
T. Dey, S.K. Mondal, M. Hashem
To effectively support the communication in such a dynamic networking environment as the ad hoc networks, the routing protocol has to be adaptable to the spatial and temporal changes in the characteristics of the network, such as traffic and mobility patterns. In this paper, we propose and analyze a routing protocol called Adaptive Monitor Based Routing (AMBR) that discovers and maintains routes in hierarchical and distributed fashion and locally repairs the broken link. The main motivation behind the proposed AMBR is to drastically cut down flooding, to substantially tame the routing overhead, to repair broken link locally in order to minimize the routing overhead and to increase efficiencies in packet movement in the ad hoc networks. An analytical model for the AMBR technique is presented. Simulation results illustrate its performance and demonstrate its good behavior comparing with other prevalent protocols. The proposed protocol achieved substantial improvement in terms of flooding, routing overhead and network overhead and hence, provides enhanced reliability.
{"title":"Performance enhancement of ad hoc networks with adaptive monitor based routing","authors":"T. Dey, S.K. Mondal, M. Hashem","doi":"10.1109/RWS.2008.4463479","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463479","url":null,"abstract":"To effectively support the communication in such a dynamic networking environment as the ad hoc networks, the routing protocol has to be adaptable to the spatial and temporal changes in the characteristics of the network, such as traffic and mobility patterns. In this paper, we propose and analyze a routing protocol called Adaptive Monitor Based Routing (AMBR) that discovers and maintains routes in hierarchical and distributed fashion and locally repairs the broken link. The main motivation behind the proposed AMBR is to drastically cut down flooding, to substantially tame the routing overhead, to repair broken link locally in order to minimize the routing overhead and to increase efficiencies in packet movement in the ad hoc networks. An analytical model for the AMBR technique is presented. Simulation results illustrate its performance and demonstrate its good behavior comparing with other prevalent protocols. The proposed protocol achieved substantial improvement in terms of flooding, routing overhead and network overhead and hence, provides enhanced reliability.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132809326","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463605
M. Angermann, W. Truszkowski
This paper discusses the role of communication and localization as enabling technologies of swarm-intelligent systems. In this work swarm-intelligence is understood as an evolving capability of decentralized, self-organized systems whose elements are collectively able to coordinate and synchronize their actions towards fulfilling a common goal. In order to share their observations of the environment, processing results or internal states, a swarm's elements form a dynamic communication network. Additionally, the swarm elements form a second network, consisting of measurements for determining their relative positions. The paper discusses the fundamental differences between these two networks and illustrates the applicability of the swarm-intelligence perspective in several application fields.
{"title":"Communication and localization networks in swarm-intelligent systems","authors":"M. Angermann, W. Truszkowski","doi":"10.1109/RWS.2008.4463605","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463605","url":null,"abstract":"This paper discusses the role of communication and localization as enabling technologies of swarm-intelligent systems. In this work swarm-intelligence is understood as an evolving capability of decentralized, self-organized systems whose elements are collectively able to coordinate and synchronize their actions towards fulfilling a common goal. In order to share their observations of the environment, processing results or internal states, a swarm's elements form a dynamic communication network. Additionally, the swarm elements form a second network, consisting of measurements for determining their relative positions. The paper discusses the fundamental differences between these two networks and illustrates the applicability of the swarm-intelligence perspective in several application fields.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131996477","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463535
J. Schwartz, J. Azaña, D. Plant
We describe a fully-electronic system for compressing and/or reversing arbitrarily-shaped waveforms in the time-domain using the principles of temporal imaging. The system accepts a arbitrary time-windowed broadband input and outputs a chirped waveform with the same envelope but compressed and/or reversed in time. We present a demonstration of a 3X time-compression and a basic time-reversal on a simple waveform and discuss the challenges and limitations of the proposed technique.
{"title":"An electronic temporal imaging system for compression and reversal of arbitrary UWB waveforms","authors":"J. Schwartz, J. Azaña, D. Plant","doi":"10.1109/RWS.2008.4463535","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463535","url":null,"abstract":"We describe a fully-electronic system for compressing and/or reversing arbitrarily-shaped waveforms in the time-domain using the principles of temporal imaging. The system accepts a arbitrary time-windowed broadband input and outputs a chirped waveform with the same envelope but compressed and/or reversed in time. We present a demonstration of a 3X time-compression and a basic time-reversal on a simple waveform and discuss the challenges and limitations of the proposed technique.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134354105","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463560
Yu Zhou, Y. Rong, Hyeong-Ah Choi, Jae-Hoon Kim, JungKyo Sohn, Hyeong-In Choi
The complementary characteristics of 3 G cellular networks (such as UMTS) and IEEE's 802.11 wireless LANs (WLANs) have stimulated intensive research efforts to integrate UMTS and WLAN networks. In such integrated networks, a mobile station is able to switch between UMTS and WLAN networks based on various network parameters such as network throughput, packet delay and other network or user quality criteria. In this paper, we develop a utility-based access selection algorithm targeted to achieve load balancing between UMTS and WLAN networks. The performance of our algorithm is evaluated using OPNET with dual-mode mobile stations.
{"title":"Utility-based load balancing in WLAN/UMTS internetworking systems","authors":"Yu Zhou, Y. Rong, Hyeong-Ah Choi, Jae-Hoon Kim, JungKyo Sohn, Hyeong-In Choi","doi":"10.1109/RWS.2008.4463560","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463560","url":null,"abstract":"The complementary characteristics of 3 G cellular networks (such as UMTS) and IEEE's 802.11 wireless LANs (WLANs) have stimulated intensive research efforts to integrate UMTS and WLAN networks. In such integrated networks, a mobile station is able to switch between UMTS and WLAN networks based on various network parameters such as network throughput, packet delay and other network or user quality criteria. In this paper, we develop a utility-based access selection algorithm targeted to achieve load balancing between UMTS and WLAN networks. The performance of our algorithm is evaluated using OPNET with dual-mode mobile stations.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114317328","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463413
Kai Li, Xiaodong Wang
We investigate the optimal design of a multihop wireless mesh network equipped with multiple orthogonal wireless channels and multiple radios. Specifically, we focus on solutions that can efficiently utilize the limited resource to support multiple unicast applications by routing and network coding. We propose a cross-layer optimization framework where the broadcasting feature of the wireless environment, which plays an important role in realizing the achievable gain of network coding, is taken into account. Moreover, we propose a network code construction scheme based on linear programming, with which the possible achievable Coding+MAC gain could be significantly increased. The proposed network design based on cross-layer optimization results in significant increase in network throughput.
{"title":"Cross-layer design of mesh networks with network coding","authors":"Kai Li, Xiaodong Wang","doi":"10.1109/RWS.2008.4463413","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463413","url":null,"abstract":"We investigate the optimal design of a multihop wireless mesh network equipped with multiple orthogonal wireless channels and multiple radios. Specifically, we focus on solutions that can efficiently utilize the limited resource to support multiple unicast applications by routing and network coding. We propose a cross-layer optimization framework where the broadcasting feature of the wireless environment, which plays an important role in realizing the achievable gain of network coding, is taken into account. Moreover, we propose a network code construction scheme based on linear programming, with which the possible achievable Coding+MAC gain could be significantly increased. The proposed network design based on cross-layer optimization results in significant increase in network throughput.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122878819","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 : 2008-03-05DOI: 10.1049/iet-cds.2008.0362
V. Rajagopal, S. Islam, M. Haider, L. Zuo
We describe a divide-by-4 injection-locked frequency divider (ILFD) based on a novel process and temperature compensation technique. The ILFD possesses a wide locking range over process corners and a wide temperature range due to the proposed compensation technique. The core of the ILFD consists of ring oscillator based on a modified version of symmetric load (Maneatis) delay elements. A calibration circuitry can be used to further enhance the locking range. Measurement results show that the proposed ILFD functions as a divide-by-4 circuit for an input frequency range from 1.8 GHz to 3.2 GHz for a power level as low as -3 dBm. The worst-case power consumption was approx. 2 mW from a 1.8 V power supply. The proposed ILFD can be used as a low-power prescaler for multi-band applications.
{"title":"A wideband Injection Locked Frequency Divider based on a process and temperature compensated ring oscillator","authors":"V. Rajagopal, S. Islam, M. Haider, L. Zuo","doi":"10.1049/iet-cds.2008.0362","DOIUrl":"https://doi.org/10.1049/iet-cds.2008.0362","url":null,"abstract":"We describe a divide-by-4 injection-locked frequency divider (ILFD) based on a novel process and temperature compensation technique. The ILFD possesses a wide locking range over process corners and a wide temperature range due to the proposed compensation technique. The core of the ILFD consists of ring oscillator based on a modified version of symmetric load (Maneatis) delay elements. A calibration circuitry can be used to further enhance the locking range. Measurement results show that the proposed ILFD functions as a divide-by-4 circuit for an input frequency range from 1.8 GHz to 3.2 GHz for a power level as low as -3 dBm. The worst-case power consumption was approx. 2 mW from a 1.8 V power supply. The proposed ILFD can be used as a low-power prescaler for multi-band applications.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123979894","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463613
N. Sasho, K. Minami, H. Fujita, T. Takahashi, K. Iimura, M. Abe, A. Yasuda
We have developed a fully integrated 0.25 mum SiGe-BiCMOS transceiver with a power amplifier (PA), transmit / receive switch (T/R SW), orthogonal modulator / demodulator, received signal strength indicator (RSSI), and phase locked loop (PLL) for Dedicated Short Range Communications (DSRC) mobile terminals with Amplifier Shift Keying (ASK) and Pi/4- shifted Quadrature Phase Shift Keying (Pi/4-QPSK) dual-mode modulation. Transmitter architecture is based on the sliding-IF topology using 4.6 GHz VCO and a 1/4 divider. Receiver architecture is based on the fixed-IF super-heterodyne. For image spurious rejection in the transmitter, a passive band elimination filter (BEF) comprised of a differential inductor is implemented. The 3.1mm x 2.97 mm die is packaged in 5.8 mm x 5.8 mm 48 pin- VQFN.
我们开发了一种完全集成的0.25 μ m SiGe-BiCMOS收发器，带有功率放大器(PA)，发射/接收开关(T/R SW)，正交调制器/解调器，接收信号强度指示器(RSSI)和锁相环(PLL)，用于专用短距离通信(DSRC)移动终端，具有放大器移位键控(ASK)和Pi/4移位正交相移键控(Pi/4- qpsk)双模调制。发射机架构基于滑动中频拓扑，使用4.6 GHz压控振荡器和1/4分频器。接收机结构基于固定中频超外差。为了抑制发射机中的图像杂散，实现了由差动电感组成的无源带消除滤波器。3.1mm x 2.97 mm芯片封装在5.8 mm x 5.8 mm 48引脚- VQFN中。
{"title":"Single-chip 5.8GHz DSRC transceiver with dual-mode of ASK and Pi/4-QPSK","authors":"N. Sasho, K. Minami, H. Fujita, T. Takahashi, K. Iimura, M. Abe, A. Yasuda","doi":"10.1109/RWS.2008.4463613","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463613","url":null,"abstract":"We have developed a fully integrated 0.25 mum SiGe-BiCMOS transceiver with a power amplifier (PA), transmit / receive switch (T/R SW), orthogonal modulator / demodulator, received signal strength indicator (RSSI), and phase locked loop (PLL) for Dedicated Short Range Communications (DSRC) mobile terminals with Amplifier Shift Keying (ASK) and Pi/4- shifted Quadrature Phase Shift Keying (Pi/4-QPSK) dual-mode modulation. Transmitter architecture is based on the sliding-IF topology using 4.6 GHz VCO and a 1/4 divider. Receiver architecture is based on the fixed-IF super-heterodyne. For image spurious rejection in the transmitter, a passive band elimination filter (BEF) comprised of a differential inductor is implemented. The 3.1mm x 2.97 mm die is packaged in 5.8 mm x 5.8 mm 48 pin- VQFN.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129516644","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 : 2008-03-05DOI: 10.1109/RWS.2008.4463575
S. Bieder, L. Haring, A. Czylwik
The capacity of a WCDMA-based cellular system like a UMTS-FDD network can be highly improved by utilizing the smart antenna concept. The received signal power of each link in the entire network can be increased by employing antenna arrays at the base station side and performing beamforming. Since the characteristics of a single antenna element have a strong influence on the amount of achievable capacity improvement, close-to-reality investigations on the network capacity must incorporate realistic antenna element characteristics. In this contribution, a UMTS-FDD network equipped with smart antennas at the base stations is analyzed on system level. Thereby, the focus lies on the impact of uncertainties in antenna position and alignment on the network capacity. Furthermore, the effect of different uplink and downlink carrier frequencies on the beamforming performance is analyzed. A simplified beamforming approach to overcome this effect is presented.
{"title":"Capacity of UMTS-FDD-based cellular systems with smart antennas in presence of position and alignment errors","authors":"S. Bieder, L. Haring, A. Czylwik","doi":"10.1109/RWS.2008.4463575","DOIUrl":"https://doi.org/10.1109/RWS.2008.4463575","url":null,"abstract":"The capacity of a WCDMA-based cellular system like a UMTS-FDD network can be highly improved by utilizing the smart antenna concept. The received signal power of each link in the entire network can be increased by employing antenna arrays at the base station side and performing beamforming. Since the characteristics of a single antenna element have a strong influence on the amount of achievable capacity improvement, close-to-reality investigations on the network capacity must incorporate realistic antenna element characteristics. In this contribution, a UMTS-FDD network equipped with smart antennas at the base stations is analyzed on system level. Thereby, the focus lies on the impact of uncertainties in antenna position and alignment on the network capacity. Furthermore, the effect of different uplink and downlink carrier frequencies on the beamforming performance is analyzed. A simplified beamforming approach to overcome this effect is presented.","PeriodicalId":431471,"journal":{"name":"2008 IEEE Radio and Wireless Symposium","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130914524","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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