Pub Date : 2010-01-10DOI: 10.1109/RWS.2010.5434112
C-P. Kao, Z. Cao, Sukhoon Oh, Y. Ryu, C. Collins
Two competing factors make for RF engineering challenges in MRI: 1) MRI at higher RF field frequencies provides higher signal-to-noise ratio and 2) MRI typically works best with a homogeneous (e.g., long wavelength) circularly-polarized RF magnetic field to excite nuclei in the region of interest. Conventional RF coils can be thought of as a series of antennas placed about the circumference of a cylinder and generating RF fields that travel into the body in the radial direction. Recently an alternative approach, with a circularly-polarized antenna sending fields along the axis of the cylinder has gained much interest. Here we use numerical methods to compare and combine the two approaches for homogeneous excitation of the human head at 300 MHz.
{"title":"Conventional volume coil and travelling-wave antenna for homogeneous excitation of the human head in MRI at 300 MHz","authors":"C-P. Kao, Z. Cao, Sukhoon Oh, Y. Ryu, C. Collins","doi":"10.1109/RWS.2010.5434112","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434112","url":null,"abstract":"Two competing factors make for RF engineering challenges in MRI: 1) MRI at higher RF field frequencies provides higher signal-to-noise ratio and 2) MRI typically works best with a homogeneous (e.g., long wavelength) circularly-polarized RF magnetic field to excite nuclei in the region of interest. Conventional RF coils can be thought of as a series of antennas placed about the circumference of a cylinder and generating RF fields that travel into the body in the radial direction. Recently an alternative approach, with a circularly-polarized antenna sending fields along the axis of the cylinder has gained much interest. Here we use numerical methods to compare and combine the two approaches for homogeneous excitation of the human head at 300 MHz.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132027684","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434246
M. Scardelletti, G. Ponchak, J. Jordan, N. Jastram, V. Mahaffey
A tunable folded slot antenna that utilizes varactor diodes is presented. The antenna is fabricated on Rogers 6006 Duriod with a dielectric constant and thickness of 6.15 and 635 µm, respectively. A copper cladding layer of 17 µm defines the antenna on the top side (no ground on backside). The antenna is fed with a CPW 50 Ω feed line, has a center frequency of 3 GHz, and incorporates Micrometrics microwave hyper-abrupt 500MHV varactors to tune the resonant frequency. The varactors have a capacitance range of 2.52 pF at 0 V to 0.4 pF at 20 V; they are placed across the radiating slot of the antenna. The tunable 10 dB bandwidth of the 3 GHz antenna is 150 MHz. The varactors also reduce the size of the antenna by 30% by capacitively loading the resonating slot line. At the center frequency, 3 GHz, the antenna has a measured return loss of 44 dB and a gain of 1.6 dBi. Full-wave electromagnetic simulations using HFSS are presented that validate the measured data.
{"title":"Tunable reduced size planar folded slot antenna utilizing varactor diodes","authors":"M. Scardelletti, G. Ponchak, J. Jordan, N. Jastram, V. Mahaffey","doi":"10.1109/RWS.2010.5434246","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434246","url":null,"abstract":"A tunable folded slot antenna that utilizes varactor diodes is presented. The antenna is fabricated on Rogers 6006 Duriod with a dielectric constant and thickness of 6.15 and 635 µm, respectively. A copper cladding layer of 17 µm defines the antenna on the top side (no ground on backside). The antenna is fed with a CPW 50 Ω feed line, has a center frequency of 3 GHz, and incorporates Micrometrics microwave hyper-abrupt 500MHV varactors to tune the resonant frequency. The varactors have a capacitance range of 2.52 pF at 0 V to 0.4 pF at 20 V; they are placed across the radiating slot of the antenna. The tunable 10 dB bandwidth of the 3 GHz antenna is 150 MHz. The varactors also reduce the size of the antenna by 30% by capacitively loading the resonating slot line. At the center frequency, 3 GHz, the antenna has a measured return loss of 44 dB and a gain of 1.6 dBi. Full-wave electromagnetic simulations using HFSS are presented that validate the measured data.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"459 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127525911","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434202
Hailong Zhu, Y. C. A. Ko, Terry Tao Ye
Dipole antennas in UHF RFID tags are driven by differential signals; it is difficult to measure the antenna input impedance accurately using single-ended probes. Furthermore, the testing fixture used in the antenna measurement process also induces additional parasitic effects; accurate measurement cannot be achieved without taking the fixture impact into consideration. In this paper, we propose to characterize the dipole antenna's input impedance using mixed mode S-parameters, the testing fixture impact can also be quantified with port extension and de-embedding techniques. Experiments demonstrate that the proposed measurement method achieves very consistent results over UHF frequency band with very high accuracy.
{"title":"Impedance measurement for balanced UHF RFID tag antennas","authors":"Hailong Zhu, Y. C. A. Ko, Terry Tao Ye","doi":"10.1109/RWS.2010.5434202","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434202","url":null,"abstract":"Dipole antennas in UHF RFID tags are driven by differential signals; it is difficult to measure the antenna input impedance accurately using single-ended probes. Furthermore, the testing fixture used in the antenna measurement process also induces additional parasitic effects; accurate measurement cannot be achieved without taking the fixture impact into consideration. In this paper, we propose to characterize the dipole antenna's input impedance using mixed mode S-parameters, the testing fixture impact can also be quantified with port extension and de-embedding techniques. Experiments demonstrate that the proposed measurement method achieves very consistent results over UHF frequency band with very high accuracy.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114980771","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434236
R. Framjee, V. Prabhu
In high bit rate DS-SS BPSK mobile radio reverse links with RAKE demodulators the frequency selective channel causes intersymbol interference. For many years the standard Gaussian approximation error rate has been used and for high bit rates its accuracy is not known. We compare the Gaussian approximation to error rate derived using total probability theorem, Chernoff and Prabhu bounds with true statistics of intersymbol interference. For signal-to-noise ratio's (SNR's) greater than 6dB (cases of interest), we show that the Gaussian approximation is a much looser upper bound than our bounds. The Prabhu bound which can be tailored to different intersymbol interference conditions is the tightest bound. We show that the RAKE combats incoherent intersymbol interference while the immunity it offers decreases for SNR's greater than 10dB. Finally, a dual space diversity RAKE provides an 8dB space diversity gain.
{"title":"Error rate considerations for a high bit rate DS-SS BPSK dual space diversity RAKE","authors":"R. Framjee, V. Prabhu","doi":"10.1109/RWS.2010.5434236","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434236","url":null,"abstract":"In high bit rate DS-SS BPSK mobile radio reverse links with RAKE demodulators the frequency selective channel causes intersymbol interference. For many years the standard Gaussian approximation error rate has been used and for high bit rates its accuracy is not known. We compare the Gaussian approximation to error rate derived using total probability theorem, Chernoff and Prabhu bounds with true statistics of intersymbol interference. For signal-to-noise ratio's (SNR's) greater than 6dB (cases of interest), we show that the Gaussian approximation is a much looser upper bound than our bounds. The Prabhu bound which can be tailored to different intersymbol interference conditions is the tightest bound. We show that the RAKE combats incoherent intersymbol interference while the immunity it offers decreases for SNR's greater than 10dB. Finally, a dual space diversity RAKE provides an 8dB space diversity gain.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115220644","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434251
Lin Cheng, Rahul Shakya
Vehicle Ad Hoc Networks (VANET) rely on frequent data exchange among vehicles to facilitate road safety, congestion control, route planning, etc. The objective of this paper is to introduce an adaptive power control method based on propagation and traffic modeling. Dual-slope pathloss and shadowing model is used to describe the power propagation. Statistical tests performed on 50289 traces extracted from real highway data establish the traffic distributions for different times of the day. We also used the Kolmogorov-Smirnov test (K-S test) for synthetically generating traces having statistical properties similar to those obtained from real data. Based on the adaptive transmission power method, the expected transmission power values for different times of the day are calculated and are compared with scenarios without power control, demonstrating the effectiveness of the proposed method.
{"title":"VANET adaptive power control from realistic propagation and traffic modeling","authors":"Lin Cheng, Rahul Shakya","doi":"10.1109/RWS.2010.5434251","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434251","url":null,"abstract":"Vehicle Ad Hoc Networks (VANET) rely on frequent data exchange among vehicles to facilitate road safety, congestion control, route planning, etc. The objective of this paper is to introduce an adaptive power control method based on propagation and traffic modeling. Dual-slope pathloss and shadowing model is used to describe the power propagation. Statistical tests performed on 50289 traces extracted from real highway data establish the traffic distributions for different times of the day. We also used the Kolmogorov-Smirnov test (K-S test) for synthetically generating traces having statistical properties similar to those obtained from real data. Based on the adaptive transmission power method, the expected transmission power values for different times of the day are calculated and are compared with scenarios without power control, demonstrating the effectiveness of the proposed method.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123013876","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434123
Gyuje Sung
A novel, simple and broadband 90° bit C-band phase shifter was proposed and fabricated by LTCC process. It is composed of an 180° transmission line and two 90° shorted transmission lines. Design equations for the proposed 90° bit phase shifter are derived by admittance parameter analyses. Based on the design equations, a broadband a 90° bit phase shifter with ±2° of phase deviation was designed and fabricated.
{"title":"Broadband 90° phase shifter using two short stubs","authors":"Gyuje Sung","doi":"10.1109/RWS.2010.5434123","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434123","url":null,"abstract":"A novel, simple and broadband 90° bit C-band phase shifter was proposed and fabricated by LTCC process. It is composed of an 180° transmission line and two 90° shorted transmission lines. Design equations for the proposed 90° bit phase shifter are derived by admittance parameter analyses. Based on the design equations, a broadband a 90° bit phase shifter with ±2° of phase deviation was designed and fabricated.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115254227","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434096
Arash Parsa, A. Ercan, P. Malagón, F. Burghardt, J. Rabaey, A. Wolisz
The explosive growth in the density of wirelessly connected devices and their traffic load is creating interference and gradually leading to a severe spectrum shortage. Approaches to address this challenge include dynamic spectrum allocation (cognitive radio) and pro-active interference mitigation strategies requiring coordination between heterogeneous networking technologies. This paper describes a modular and scalable methodology and architecture, called Connectivity Brokerage, that enables proactive co-existence and collaboration between diverse technologies, making joint optimization of the scarce spectrum resources possible.
{"title":"Connectivity Brokerage: From coexistence to collaboration","authors":"Arash Parsa, A. Ercan, P. Malagón, F. Burghardt, J. Rabaey, A. Wolisz","doi":"10.1109/RWS.2010.5434096","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434096","url":null,"abstract":"The explosive growth in the density of wirelessly connected devices and their traffic load is creating interference and gradually leading to a severe spectrum shortage. Approaches to address this challenge include dynamic spectrum allocation (cognitive radio) and pro-active interference mitigation strategies requiring coordination between heterogeneous networking technologies. This paper describes a modular and scalable methodology and architecture, called Connectivity Brokerage, that enables proactive co-existence and collaboration between diverse technologies, making joint optimization of the scarce spectrum resources possible.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129404874","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434183
William B. Sorsby, Timothy L. Kean, Scott L. Heibel, G. Hegazi
Spectrally-efficient high peak-to-average power ratio (PAPR) waveforms exhibit disadvantages compared to constant-envelope waveforms for frequency-agile systems when power-efficiency is paramount. EER and Envelope Tracking offer high efficiency but require precise adjustment and wide bandwidth power supplies/modulators. Frequency agility introduces implementation complexities when systems must tune wide frequency ranges or cover multiple channels. Combining advantages of Envelope Tracking and EER, a partial-envelope tracking power amplifier system demonstrates robust operation across multiple channels, requires no frequency dependent adjustments, and exhibits excellent spectral purity combined with high power-efficiency. Experimental UHF data shows 135 watts of output power with 55% efficiency using LDMOS devices, for uplink WCDMA (approximately 4dB PAPR).
{"title":"Practical high-efficiency partial-Envelope Tracking power amplifier system with broadband applications","authors":"William B. Sorsby, Timothy L. Kean, Scott L. Heibel, G. Hegazi","doi":"10.1109/RWS.2010.5434183","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434183","url":null,"abstract":"Spectrally-efficient high peak-to-average power ratio (PAPR) waveforms exhibit disadvantages compared to constant-envelope waveforms for frequency-agile systems when power-efficiency is paramount. EER and Envelope Tracking offer high efficiency but require precise adjustment and wide bandwidth power supplies/modulators. Frequency agility introduces implementation complexities when systems must tune wide frequency ranges or cover multiple channels. Combining advantages of Envelope Tracking and EER, a partial-envelope tracking power amplifier system demonstrates robust operation across multiple channels, requires no frequency dependent adjustments, and exhibits excellent spectral purity combined with high power-efficiency. Experimental UHF data shows 135 watts of output power with 55% efficiency using LDMOS devices, for uplink WCDMA (approximately 4dB PAPR).","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128939980","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434255
A. Ashtekar, A. Kovacs, F. Sadeghi, D. Peroulis
We demonstrate for the first time a low-cost battery-free wireless telemeter integrated on a dynamically balanced ball bearing operating in a test setup that mimics the operating conditions of a two-compressor turbocharger. In this method we continuously monitor the bearing cage temperature and demonstrate the ability to detect rotor imbalance during operation even at low speeds below 5,550 RPM. The telemeter is based on a simple commercially-available temperature-sensitive capacitor coupled with an inductor that is mounted on the bearing cage and is able to operate at temperatures up to 150°C. Cage temperature is sensed wirelessly through a matched interrogator tuned to the natural frequency of the cage sensor at 13.1 MHz. A 5°C temperature differential is detected at 4,700 RPM between a balanced rotor and one with an applied 2.32×10{−3} kg-m imbalance.
{"title":"Bearing cage telemeter for the detection of shaft imbalance in rotating systems","authors":"A. Ashtekar, A. Kovacs, F. Sadeghi, D. Peroulis","doi":"10.1109/RWS.2010.5434255","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434255","url":null,"abstract":"We demonstrate for the first time a low-cost battery-free wireless telemeter integrated on a dynamically balanced ball bearing operating in a test setup that mimics the operating conditions of a two-compressor turbocharger. In this method we continuously monitor the bearing cage temperature and demonstrate the ability to detect rotor imbalance during operation even at low speeds below 5,550 RPM. The telemeter is based on a simple commercially-available temperature-sensitive capacitor coupled with an inductor that is mounted on the bearing cage and is able to operate at temperatures up to 150°C. Cage temperature is sensed wirelessly through a matched interrogator tuned to the natural frequency of the cage sensor at 13.1 MHz. A 5°C temperature differential is detected at 4,700 RPM between a balanced rotor and one with an applied 2.32×10{−3} kg-m imbalance.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124661860","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 : 2010-01-10DOI: 10.1109/RWS.2010.5434193
Siamak Yousefi, T. Eriksson, D. Kuylenstierna
A novel model of the RF oscillator's phase noise process has been provided in this work, resulting in a more accurate model than the conventional Wiener process. The phase noise is considered as the integration of frequency noise which consists of white and flicker noise, whereas the Wiener process is the integration result of white noise only. Analytical expressions of the oscillator RMS jitter and the Single-Side Band (SSB) phase noise (L) are presented and compared to the simulation and measurement results for verification. The relationship between 1/f3-1/f2 corner frequency in the PSD and the slope transition corner in RMS jitter plot is consistent with the analytical and measurement results. The simulation result shows that the PSD of the oscillator becomes Gaussian close to the carrier, followed by power-law regions, in consistense with the analytical expression.
{"title":"A novel model for simulation of RF oscillator phase noise","authors":"Siamak Yousefi, T. Eriksson, D. Kuylenstierna","doi":"10.1109/RWS.2010.5434193","DOIUrl":"https://doi.org/10.1109/RWS.2010.5434193","url":null,"abstract":"A novel model of the RF oscillator's phase noise process has been provided in this work, resulting in a more accurate model than the conventional Wiener process. The phase noise is considered as the integration of frequency noise which consists of white and flicker noise, whereas the Wiener process is the integration result of white noise only. Analytical expressions of the oscillator RMS jitter and the Single-Side Band (SSB) phase noise (L) are presented and compared to the simulation and measurement results for verification. The relationship between 1/f3-1/f2 corner frequency in the PSD and the slope transition corner in RMS jitter plot is consistent with the analytical and measurement results. The simulation result shows that the PSD of the oscillator becomes Gaussian close to the carrier, followed by power-law regions, in consistense with the analytical expression.","PeriodicalId":334671,"journal":{"name":"2010 IEEE Radio and Wireless Symposium (RWS)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126434211","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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