Pub Date : 2011-10-24DOI: 10.1109/ICUWB.2011.6058922
Muhammad Gufran Khan, B. Sallberg, J. Nordberg, I. Claesson
This paper presents a combined binary pulse position modulation (BPPM)/code-multiplexed transmitted-reference (CM-TR) ultra wideband (UWB) system. The low complexity CM-TR UWB is not energy efficient as one half of the energy is used to transmit reference pulses and, even at low-to-medium data rates, it suffers from strong multi-user interference (MUI) and inter-frame interference (IFI). Keeping the information rate constant, the combined BPPM/CM-TR UWB system utilizes 3 dB less energy per bit as compared to the CM-TR system and achieves relatively longer silent periods between the pulses, which not only mitigate the IFI but also decrease the MUI due to less collisions with other asynchronous users. In the high SNR region, where the effect of IFI and MUI severely degrades the bit-error-rate (BER) performance of the multiuser CM-TR system, simulation results verify that the multiuser BPPM/CM-TR outperforms the multiuser CM-TR system.
{"title":"Energy efficient binary PPM/code-multiplexed transmitted-reference multi-user UWB system","authors":"Muhammad Gufran Khan, B. Sallberg, J. Nordberg, I. Claesson","doi":"10.1109/ICUWB.2011.6058922","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058922","url":null,"abstract":"This paper presents a combined binary pulse position modulation (BPPM)/code-multiplexed transmitted-reference (CM-TR) ultra wideband (UWB) system. The low complexity CM-TR UWB is not energy efficient as one half of the energy is used to transmit reference pulses and, even at low-to-medium data rates, it suffers from strong multi-user interference (MUI) and inter-frame interference (IFI). Keeping the information rate constant, the combined BPPM/CM-TR UWB system utilizes 3 dB less energy per bit as compared to the CM-TR system and achieves relatively longer silent periods between the pulses, which not only mitigate the IFI but also decrease the MUI due to less collisions with other asynchronous users. In the high SNR region, where the effect of IFI and MUI severely degrades the bit-error-rate (BER) performance of the multiuser CM-TR system, simulation results verify that the multiuser BPPM/CM-TR outperforms the multiuser CM-TR system.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131456963","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058910
P. Meissner, D. Arnitz, T. Gigl, K. Witrisal
We present a detailed analysis of an indoor UWB channel measurement campaign. The focus is on the modeling of the deterministic part of the multipath channel using a-priori known relevant reflections and scatterers, found from an available floor plan. Our approach uses virtual signal sources, whose locations and visibilities can be calculated using simple ray-launching techniques. The channel analysis steps exploit these results, using an effective multipath cancellation method that introduces virtually no artifacts. We show that the corresponding multipath-components can explain up to 90% of the UWB channel impulse responses in terms of energy capture. This is important for multipath-aided indoor localization, which provides robust position fixes using a single base station only.
{"title":"Analysis of an indoor UWB channel for multipath-aided localization","authors":"P. Meissner, D. Arnitz, T. Gigl, K. Witrisal","doi":"10.1109/ICUWB.2011.6058910","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058910","url":null,"abstract":"We present a detailed analysis of an indoor UWB channel measurement campaign. The focus is on the modeling of the deterministic part of the multipath channel using a-priori known relevant reflections and scatterers, found from an available floor plan. Our approach uses virtual signal sources, whose locations and visibilities can be calculated using simple ray-launching techniques. The channel analysis steps exploit these results, using an effective multipath cancellation method that introduces virtually no artifacts. We show that the corresponding multipath-components can explain up to 90% of the UWB channel impulse responses in terms of energy capture. This is important for multipath-aided indoor localization, which provides robust position fixes using a single base station only.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133956059","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058918
P. Gao, Zhiqiang Li, Yi Zheng
A small-size, low-profile, and planar integrated antenna is presented. This antenna is fed by a microstrip line and built on a PTFE substrate with only 20mm*46mm and the overall size of the radiating element is 15mm*16mm. A semicircular slot resonator and a split ring slot resonator are embedded in the radiating patch. The bandwidth of this antenna is 2.25–11.25GHz which covers UWB (IEEE 802.15.3a, 3.1–10.6GHz) and Bluetooth (IEEE 802.15.1, 2.4–2.484GHz), but with dual WLAN band-notched of 4.96–5.29 GHz and 5.54–6.01 GHz.
{"title":"An integrated UWB and bluetooth antenna with dual WLAN band-notched","authors":"P. Gao, Zhiqiang Li, Yi Zheng","doi":"10.1109/ICUWB.2011.6058918","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058918","url":null,"abstract":"A small-size, low-profile, and planar integrated antenna is presented. This antenna is fed by a microstrip line and built on a PTFE substrate with only 20mm*46mm and the overall size of the radiating element is 15mm*16mm. A semicircular slot resonator and a split ring slot resonator are embedded in the radiating patch. The bandwidth of this antenna is 2.25–11.25GHz which covers UWB (IEEE 802.15.3a, 3.1–10.6GHz) and Bluetooth (IEEE 802.15.1, 2.4–2.484GHz), but with dual WLAN band-notched of 4.96–5.29 GHz and 5.54–6.01 GHz.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134092114","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058862
Xuyang Li, M. Jalilvand, L. Zwirello, T. Zwick
This paper presents a synthetic aperture-based UWB radar imaging system. The goal is to detect the urine accumulation in the human bladder. To verify this radar concept a bladder model with various human tissues including realistic dielectric properties is simulated. Two scan configurations with different antenna positions are used to investigate the influence of the synthetic aperture length and position number in the microwave images. To generate the imaging results, Delay and Sum algorithm together with coherent weighting is applied. The achieved imaging results demonstrate the possibility of detecting the position and volume of urine in the human bladder and therefore the potential application of this radar imaging system in the clinics for diagnosis purposes.
{"title":"Synthetic aperture-based UWB imaging system for detection of urine accumulation in human bladder","authors":"Xuyang Li, M. Jalilvand, L. Zwirello, T. Zwick","doi":"10.1109/ICUWB.2011.6058862","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058862","url":null,"abstract":"This paper presents a synthetic aperture-based UWB radar imaging system. The goal is to detect the urine accumulation in the human bladder. To verify this radar concept a bladder model with various human tissues including realistic dielectric properties is simulated. Two scan configurations with different antenna positions are used to investigate the influence of the synthetic aperture length and position number in the microwave images. To generate the imaging results, Delay and Sum algorithm together with coherent weighting is applied. The achieved imaging results demonstrate the possibility of detecting the position and volume of urine in the human bladder and therefore the potential application of this radar imaging system in the clinics for diagnosis purposes.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130755057","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058858
Xubo Wang, A. Dinh, D. Teng
In this paper, an UWB transmitter for next generation bio-radar sensing system characterized by a high data rate, low area, low power consumption, and low complexity, and specifically designed to fit Canada UWB spectrum mask, is proposed for real-time bio-medical sensing. The transmitter is based on an all digitally controlled circuit pulse generator in 90nm CMOS to generate the tenth-order derivative of Gaussian pulse with bi-phase modulation scheme operating in the 6–10GHz band specified by Canada draft spectrum specification. The switch diplexer presents a 0.5dB insertion loss. The transmitter core occupies an chip area of 200um×140um. Simulating on a 1V voltage supply, the transmitter draws average 9.037mW when generating the tenth-order Gaussian derivative pulses at a pulse repetition frequency of 50MHz. The transmitter has an output power of 7.08dBm and each pulse carries an energy of 3.1pJ.The pulse is digitally synthesized and bi-phase modulated. This transmitter prototype can generate any other pulse combinations with minor design modifications. The predicted performance of the bio-radar is also evaluated and discussed.
{"title":"Ultra wide-band high-order pulse digital transmitter IC in 90nm CMOS for biomedical radar sensing","authors":"Xubo Wang, A. Dinh, D. Teng","doi":"10.1109/ICUWB.2011.6058858","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058858","url":null,"abstract":"In this paper, an UWB transmitter for next generation bio-radar sensing system characterized by a high data rate, low area, low power consumption, and low complexity, and specifically designed to fit Canada UWB spectrum mask, is proposed for real-time bio-medical sensing. The transmitter is based on an all digitally controlled circuit pulse generator in 90nm CMOS to generate the tenth-order derivative of Gaussian pulse with bi-phase modulation scheme operating in the 6–10GHz band specified by Canada draft spectrum specification. The switch diplexer presents a 0.5dB insertion loss. The transmitter core occupies an chip area of 200um×140um. Simulating on a 1V voltage supply, the transmitter draws average 9.037mW when generating the tenth-order Gaussian derivative pulses at a pulse repetition frequency of 50MHz. The transmitter has an output power of 7.08dBm and each pulse carries an energy of 3.1pJ.The pulse is digitally synthesized and bi-phase modulated. This transmitter prototype can generate any other pulse combinations with minor design modifications. The predicted performance of the bio-radar is also evaluated and discussed.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133719729","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058825
Yanpeng Ma, F. Sun, Weidong Wang
The timing acquisition of IR-UWB system with very short pulse is difficult to implement due to high sampling rate and high resolution ADC. In this paper, a new two-step timing acquisition method combining energy detection (ED) scheme with the monobit digital receiver is proposed. The usage of the monobit digital receiver, with the comparator instead of high resolution ADC, can reduce the complexity greatly; using the ED scheme to cut down the received data region, the computational load of digital signal processing (DSP) part can be decreased significantly. The acquisition probability of each step is analyzed in this paper. The performance of this approach is also demonstrated comparing with separate monobit and ED methods via simulation.
{"title":"A two-step IR-UWB acquisition method based on monobit receiver","authors":"Yanpeng Ma, F. Sun, Weidong Wang","doi":"10.1109/ICUWB.2011.6058825","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058825","url":null,"abstract":"The timing acquisition of IR-UWB system with very short pulse is difficult to implement due to high sampling rate and high resolution ADC. In this paper, a new two-step timing acquisition method combining energy detection (ED) scheme with the monobit digital receiver is proposed. The usage of the monobit digital receiver, with the comparator instead of high resolution ADC, can reduce the complexity greatly; using the ED scheme to cut down the received data region, the computational load of digital signal processing (DSP) part can be decreased significantly. The acquisition probability of each step is analyzed in this paper. The performance of this approach is also demonstrated comparing with separate monobit and ED methods via simulation.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132370127","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058807
D. Lin, A. Trasser, H. Schumacher
This paper presents a 3.1—10.6 GHz ultra-wideband transmitter/receiver chipset for non-coherent communication and localization applications. Its fully differential topology fits promising balanced UWB antennas, and eases packaging. The transmitter uses a cross-coupled oscillator core transiently turned on by a current spike. It consumes 6 mW at 100 MHz impulse repetion rate, including the on-chip pulse shaping circuitry. The energy-detecting receiver front-end combines a fully differential low noise amplifier (LNA), a differential squaring circuit, low pass filters and buffers. The complete receiver IC dissipates 108 mW, almost independent of the applied impulse rate. Transmit and receive ICs are mounted chip-on-board at the feedpoints of dipole fed circular slot antennas. The measurement results suggest communication speeds up to 700 MBaud using on-off keying.
{"title":"A fully differential IR-UWB front-end for noncoherent communication and localization","authors":"D. Lin, A. Trasser, H. Schumacher","doi":"10.1109/ICUWB.2011.6058807","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058807","url":null,"abstract":"This paper presents a 3.1—10.6 GHz ultra-wideband transmitter/receiver chipset for non-coherent communication and localization applications. Its fully differential topology fits promising balanced UWB antennas, and eases packaging. The transmitter uses a cross-coupled oscillator core transiently turned on by a current spike. It consumes 6 mW at 100 MHz impulse repetion rate, including the on-chip pulse shaping circuitry. The energy-detecting receiver front-end combines a fully differential low noise amplifier (LNA), a differential squaring circuit, low pass filters and buffers. The complete receiver IC dissipates 108 mW, almost independent of the applied impulse rate. Transmit and receive ICs are mounted chip-on-board at the feedpoints of dipole fed circular slot antennas. The measurement results suggest communication speeds up to 700 MBaud using on-off keying.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132214190","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058929
G. Ruvio, M. Ammann, M. John, R. Solimene, A. D'Alterio, R. Pierri
A detection algorithm is introduced for breast cancer diagnostics. A coaxial skin+breast tissue phantom has been used for numerical evaluations. The algorithm has been validated with both ideal and realistic sources. In particular, an antipodal Vivaldi antenna operating in the frequency range 1 – 2.5 GHz has been properly optimized for this application. A 5 mm thick tumor has been correctly detected in three different scenarios inside the breast tissue spanning from a subcutaneous to a deeper location.
{"title":"UWB breast cancer detection with numerical phantom and Vivaldi antenna","authors":"G. Ruvio, M. Ammann, M. John, R. Solimene, A. D'Alterio, R. Pierri","doi":"10.1109/ICUWB.2011.6058929","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058929","url":null,"abstract":"A detection algorithm is introduced for breast cancer diagnostics. A coaxial skin+breast tissue phantom has been used for numerical evaluations. The algorithm has been validated with both ideal and realistic sources. In particular, an antipodal Vivaldi antenna operating in the frequency range 1 – 2.5 GHz has been properly optimized for this application. A 5 mm thick tumor has been correctly detected in three different scenarios inside the breast tissue spanning from a subcutaneous to a deeper location.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129408591","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058816
Ruiqing Ye, Huaping Liu
In this paper, a three-dimensional (3-D) ultra-wideband time-of-arrival localization scheme that employs a single cluster of receivers is studied. The receivers are placed on a two-dimensional plane within a few decimeters, and no wireless synchronization is required among the receivers. The optimum 3-D receiver placement is analyzed in the sense of minimum estimation variance defined by the Cramér-Rao lower bound. The position error bound as a function of the number of receivers and the distance between the source and the receiver unit is derived. An average position estimation error of 26.6 cm is achieved in experiments when the transmitter is within 10 meters of the receiver unit, where four receivers are placed in the same place within a circle of radius 50 cm.
{"title":"Ultra-wideband localization with collocated receivers","authors":"Ruiqing Ye, Huaping Liu","doi":"10.1109/ICUWB.2011.6058816","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058816","url":null,"abstract":"In this paper, a three-dimensional (3-D) ultra-wideband time-of-arrival localization scheme that employs a single cluster of receivers is studied. The receivers are placed on a two-dimensional plane within a few decimeters, and no wireless synchronization is required among the receivers. The optimum 3-D receiver placement is analyzed in the sense of minimum estimation variance defined by the Cramér-Rao lower bound. The position error bound as a function of the number of receivers and the distance between the source and the receiver unit is derived. An average position estimation error of 26.6 cm is achieved in experiments when the transmitter is within 10 meters of the receiver unit, where four receivers are placed in the same place within a circle of radius 50 cm.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133698861","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 : 2011-10-24DOI: 10.1109/ICUWB.2011.6058865
E. Lagunas, M. Nájar
Channel estimation for purposes of equalization is a long standing problem in signal processing. Wireless propagation is characterized by sparse channels, that is channels whose time domain impulse response consists of few dominant multipath fingers. This paper examines the use of Compressed Sensing (CS) in the estimation of highly sparse channels. In particular, a new channel sparse model for ultra-wideband (UWB) communication systems based on the frequency domain signal model is presented. A new greedy algorithm named extended OMP (eOMP) is proposed to reduce the false path detection achieved with classical Orthogonal Matching Pursuit (OMP) allowing better time of arrival (TOA) estimation.
{"title":"Sparse channel estimation based on compressed sensing for ultra wideband systems","authors":"E. Lagunas, M. Nájar","doi":"10.1109/ICUWB.2011.6058865","DOIUrl":"https://doi.org/10.1109/ICUWB.2011.6058865","url":null,"abstract":"Channel estimation for purposes of equalization is a long standing problem in signal processing. Wireless propagation is characterized by sparse channels, that is channels whose time domain impulse response consists of few dominant multipath fingers. This paper examines the use of Compressed Sensing (CS) in the estimation of highly sparse channels. In particular, a new channel sparse model for ultra-wideband (UWB) communication systems based on the frequency domain signal model is presented. A new greedy algorithm named extended OMP (eOMP) is proposed to reduce the false path detection achieved with classical Orthogonal Matching Pursuit (OMP) allowing better time of arrival (TOA) estimation.","PeriodicalId":143107,"journal":{"name":"2011 IEEE International Conference on Ultra-Wideband (ICUWB)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133545824","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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