Pub Date : 2007-06-04DOI: 10.1109/WDDC.2007.4339405
K. J. Sohn, Hongbin Li, B. Himed, J. S. Markow
We consider the problem of detecting a multichannel signal in the presence of spatially and temporally colored disturbances. The parametric Rao and GLRT detectors, recently developed by exploiting a multichannel autoregressive (AR) model for the disturbance, have been shown to perform well with limited or even no range training data. The performance of the parametric detectors, however, has been evaluated through the limited computer simulations. The disturbances were generated to follow the exact multichannel AR processes and independently from each other with the same distribution whereas the disturbances in an airborne radar environment do not follow the exact multichannel AR model. In this paper, we evaluate the detection performance of the parametric Rao and GLRT detectors using airborne data obtained from the multi-channel airborne radar measurement (MCARM) database. This data contain typical clutter found in airborne radar systems, and cover a variety of scenarios including dense-target or heterogeneous environment Numerical results show that the parametric Rao and GLRT detectors work well with limited or even no range training data in an airborne radar environment.
{"title":"Multichannel parametric detectors for airborne radar applications","authors":"K. J. Sohn, Hongbin Li, B. Himed, J. S. Markow","doi":"10.1109/WDDC.2007.4339405","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339405","url":null,"abstract":"We consider the problem of detecting a multichannel signal in the presence of spatially and temporally colored disturbances. The parametric Rao and GLRT detectors, recently developed by exploiting a multichannel autoregressive (AR) model for the disturbance, have been shown to perform well with limited or even no range training data. The performance of the parametric detectors, however, has been evaluated through the limited computer simulations. The disturbances were generated to follow the exact multichannel AR processes and independently from each other with the same distribution whereas the disturbances in an airborne radar environment do not follow the exact multichannel AR model. In this paper, we evaluate the detection performance of the parametric Rao and GLRT detectors using airborne data obtained from the multi-channel airborne radar measurement (MCARM) database. This data contain typical clutter found in airborne radar systems, and cover a variety of scenarios including dense-target or heterogeneous environment Numerical results show that the parametric Rao and GLRT detectors work well with limited or even no range training data in an airborne radar environment.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131377014","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339435
K. Morrison
The use of SAR and ISAR imaging is an important tool in the laboratory RCS characterization of scattering patterns across signature critical platforms. Despite measures to the contrary, air turbulence and mechanical vibration can produce unwanted complex perturbations of the target during the imaging process. The slow sweep time of many laboratory stepped-frequency CW radars means that a target can undergo significant motion even during a sweep, leading to substantial and time-varying defocusing of range profiles, unsuited to conventional motion-correction schemes. Model code was written to provide simulations of representative complex motions for a string-suspended target. Comparison of images produced using monotonic and randomized waveforms could detail the presence and pattern of very small motion-related changes in RCS. The ability to do this was found to have a complex dependence on the relative lengths of the radar sweep time and the characteristic oscillation period of the motion. When the sweep time and oscillation period are comparable, it may be possible to accurately retrieve the target's entire motion history, from the phase perturbation recoverable from the difference of the monotonic and randomized waveforms in the raw frequency domain. This can then be applied back to the data as a motion correction.
{"title":"Use of frequency-randomized SAR waveforms for the detection and mitigation of small-motion effects in precision RCS measurement","authors":"K. Morrison","doi":"10.1109/WDDC.2007.4339435","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339435","url":null,"abstract":"The use of SAR and ISAR imaging is an important tool in the laboratory RCS characterization of scattering patterns across signature critical platforms. Despite measures to the contrary, air turbulence and mechanical vibration can produce unwanted complex perturbations of the target during the imaging process. The slow sweep time of many laboratory stepped-frequency CW radars means that a target can undergo significant motion even during a sweep, leading to substantial and time-varying defocusing of range profiles, unsuited to conventional motion-correction schemes. Model code was written to provide simulations of representative complex motions for a string-suspended target. Comparison of images produced using monotonic and randomized waveforms could detail the presence and pattern of very small motion-related changes in RCS. The ability to do this was found to have a complex dependence on the relative lengths of the radar sweep time and the characteristic oscillation period of the motion. When the sweep time and oscillation period are comparable, it may be possible to accurately retrieve the target's entire motion history, from the phase perturbation recoverable from the difference of the monotonic and randomized waveforms in the raw frequency domain. This can then be applied back to the data as a motion correction.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134297276","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339459
L. Facheris, F. Cuccoli
The NDSA (normalized differential spectral absorption) method is a novel differential measurement way for estimating the total content of water vapor (IWV, integrated water vapor) along a tropospheric propagation path between two low Earth orbit (LEO) satellites. NDSA is based on the simultaneous measurement of the total attenuation at two relatively close frequencies in the Ku/K bands, and on the estimate of a "spectral sensitivity parameter" that can be directly converted into IWV. NDSA is potentially able to emphasize the water vapor contribution, to cancel out all spectrally flat unwanted contributions and to limit the impairments due to tropospheric scintillation. NDSA performance may change with the altitude at which the radio path is located with respect to the Earth. Therefore, after having examined through some simulations accounting for thermal noise at the receiver and tropospheric scintillation effects its measurement performance, we propose here an adaptive approach to the NDSA method in the case of two counter-rotating LEO satellites, based on the estimation of the signal to noise ratio and the change of the central frequency.
{"title":"Measuring tropospheric water vapor by normalized differential power measurements: an adaptive approach","authors":"L. Facheris, F. Cuccoli","doi":"10.1109/WDDC.2007.4339459","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339459","url":null,"abstract":"The NDSA (normalized differential spectral absorption) method is a novel differential measurement way for estimating the total content of water vapor (IWV, integrated water vapor) along a tropospheric propagation path between two low Earth orbit (LEO) satellites. NDSA is based on the simultaneous measurement of the total attenuation at two relatively close frequencies in the Ku/K bands, and on the estimate of a \"spectral sensitivity parameter\" that can be directly converted into IWV. NDSA is potentially able to emphasize the water vapor contribution, to cancel out all spectrally flat unwanted contributions and to limit the impairments due to tropospheric scintillation. NDSA performance may change with the altitude at which the radio path is located with respect to the Earth. Therefore, after having examined through some simulations accounting for thermal noise at the receiver and tropospheric scintillation effects its measurement performance, we propose here an adaptive approach to the NDSA method in the case of two counter-rotating LEO satellites, based on the estimation of the signal to noise ratio and the change of the central frequency.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132249354","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339425
L. Valbonesi, R. Ansari
High peak-to-average power ratio (PAPR) is one of the major drawbacks of orthogonal frequency division multiplexing (OFDM). In [8] a low-complexity probabilistic scheme to reduce PAPR in OFDM, called erasure pattern selection (EPS), was proposed. The EPS scheme described in [8] requires the transmission of side information with proper coding. In this paper we address waveform design for OFDM transmission and investigate a method that avoids transmission of side information. Simulation results show that the probability of incorrect detection of the selected erasure pattern is smaller than 10-3 for SNR larger than 6 dB. This means that only 1 in 1000 symbols have to be retransmitted. Also, EPS provide a reduction in PAPR of about 1.5 dB.
{"title":"Low-complexity EPS scheme for PAPR reduction in OFDM with no transmission of side information","authors":"L. Valbonesi, R. Ansari","doi":"10.1109/WDDC.2007.4339425","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339425","url":null,"abstract":"High peak-to-average power ratio (PAPR) is one of the major drawbacks of orthogonal frequency division multiplexing (OFDM). In [8] a low-complexity probabilistic scheme to reduce PAPR in OFDM, called erasure pattern selection (EPS), was proposed. The EPS scheme described in [8] requires the transmission of side information with proper coding. In this paper we address waveform design for OFDM transmission and investigate a method that avoids transmission of side information. Simulation results show that the probability of incorrect detection of the selected erasure pattern is smaller than 10-3 for SNR larger than 6 dB. This means that only 1 in 1000 symbols have to be retransmitted. Also, EPS provide a reduction in PAPR of about 1.5 dB.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124250582","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339433
D. Fuhrmann, G. San Antonio
Motivated by problems in waveform-agile sensing systems, we consider the application of an optimal measurement selection technique to discrete-time Kalman and extended Kalman filters. The optimal linear measurement is selected prior to taking the observation at each step of the filter. The measurement is described through a measurement matrix B that depends on the prior state covariance, the available energy, and the observation noise variance. The tracking performance of this method is compared to that obtained using other measurement techniques. Our simulations suggest that the performance improvement is most pronounced when the dimension of the state space is large, there is a large eigenvalue spread in the prior covariance, and the signal-to-noise ratio is low.
{"title":"Kalman filter and extended Kalman filter using one-step optimal measurement selection","authors":"D. Fuhrmann, G. San Antonio","doi":"10.1109/WDDC.2007.4339433","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339433","url":null,"abstract":"Motivated by problems in waveform-agile sensing systems, we consider the application of an optimal measurement selection technique to discrete-time Kalman and extended Kalman filters. The optimal linear measurement is selected prior to taking the observation at each step of the filter. The measurement is described through a measurement matrix B that depends on the prior state covariance, the available energy, and the observation noise variance. The tracking performance of this method is compared to that obtained using other measurement techniques. Our simulations suggest that the performance improvement is most pronounced when the dimension of the state space is large, there is a large eigenvalue spread in the prior covariance, and the signal-to-noise ratio is low.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122449996","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339454
G. Frazer, B.A. Johnson, Y. Abramovich
HF skywave radar performance and flexibility can benefit from transmission of multiple orthogonal waveforms in a multiple-input, multiple-output (MIMO) radar architecture. Several practical limitations need to be considered in such a design. One issue is that many HF radar transmit arrays are over-sampled spatially to allow for operation over a significant portion of the HF band. Transmission of orthogonal waveforms in this case can result in large reactive power and consequent equipment damage. Another issue is the ability to generate orthogonal waveform sets with sufficient cardinality at the low time-bandwidth products typical of aircraft surveillance operation. There are likely to be fewer waveforms than transmit elements and so some form of spatial rank expansion, from waveform to radiated signal, is required. Both of these issues are examined using Maric-Titlebaum frequency-hop codes as one example of an orthogonal waveform set.
{"title":"Orthogonal waveform support in MIMO HF OTH radars","authors":"G. Frazer, B.A. Johnson, Y. Abramovich","doi":"10.1109/WDDC.2007.4339454","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339454","url":null,"abstract":"HF skywave radar performance and flexibility can benefit from transmission of multiple orthogonal waveforms in a multiple-input, multiple-output (MIMO) radar architecture. Several practical limitations need to be considered in such a design. One issue is that many HF radar transmit arrays are over-sampled spatially to allow for operation over a significant portion of the HF band. Transmission of orthogonal waveforms in this case can result in large reactive power and consequent equipment damage. Another issue is the ability to generate orthogonal waveform sets with sufficient cardinality at the low time-bandwidth products typical of aircraft surveillance operation. There are likely to be fewer waveforms than transmit elements and so some form of spatial rank expansion, from waveform to radiated signal, is required. Both of these issues are examined using Maric-Titlebaum frequency-hop codes as one example of an orthogonal waveform set.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125804711","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339374
D. Zito, D. Pepe, B. Neri, D. De Rossi
In February 2002 the FCC authorized the marketing of a new class of radiofrequency devices: the ultra-wide-band (UWB) systems. One of the most interesting applications for which the UWB systems are addressed is related to the medical imaging. This paper addresses the feasibility study of a novel fully integrated 3.1-10.6 GHz UWB radar on a standard silicon technology for the heart wall monitoring. A theoretical frequency-dependent model of the losses of the electromagnetic radiation in the channel (the human chest) in which the radar operates has been derived. The preliminary specifications of each building blocks have been derived by basic theory in the conditions of the addressed scenario. System simulations have been carried out by means of the Ptolemy simulator within Agilent ADS2005ATM in order to claim the preliminary theoretical study. The CAD analyses have shown that the correlator-based radar topology allows us to approach the realization of such a system-on-a-chip pulse radar in a modern silicon technology (as such as the standard CMOS 90 nm).
{"title":"Feasibility study of a low-cost system-on-a-chip UWB pulse radar on silicon for the heart monitoring","authors":"D. Zito, D. Pepe, B. Neri, D. De Rossi","doi":"10.1109/WDDC.2007.4339374","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339374","url":null,"abstract":"In February 2002 the FCC authorized the marketing of a new class of radiofrequency devices: the ultra-wide-band (UWB) systems. One of the most interesting applications for which the UWB systems are addressed is related to the medical imaging. This paper addresses the feasibility study of a novel fully integrated 3.1-10.6 GHz UWB radar on a standard silicon technology for the heart wall monitoring. A theoretical frequency-dependent model of the losses of the electromagnetic radiation in the channel (the human chest) in which the radar operates has been derived. The preliminary specifications of each building blocks have been derived by basic theory in the conditions of the addressed scenario. System simulations have been carried out by means of the Ptolemy simulator within Agilent ADS2005ATM in order to claim the preliminary theoretical study. The CAD analyses have shown that the correlator-based radar topology allows us to approach the realization of such a system-on-a-chip pulse radar in a modern silicon technology (as such as the standard CMOS 90 nm).","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128397711","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339430
F. Lombardini, M. Pardini, F. Gini
SAR tomography is an emerging technique which can be used to derive full 3D SAR images of the observed areas. It is based on the Fourier elevation focusing of the signal acquired by means of baseline diversity. Unfortunately, the spatial baseline distribution is typically non-uniform, resulting in an unsatisfactory image quality. In this work, we improve the basic elevation focusing technique by reconstructing a set of uniform baselines data exploiting a light a priori information, i.e. the height sector which contains the scatterers. The validity of the method has been evaluated by carrying out simulated analyses for different scenarios.
{"title":"Sector interpolation for 3D SAR imaging with baseline diversity data","authors":"F. Lombardini, M. Pardini, F. Gini","doi":"10.1109/WDDC.2007.4339430","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339430","url":null,"abstract":"SAR tomography is an emerging technique which can be used to derive full 3D SAR images of the observed areas. It is based on the Fourier elevation focusing of the signal acquired by means of baseline diversity. Unfortunately, the spatial baseline distribution is typically non-uniform, resulting in an unsatisfactory image quality. In this work, we improve the basic elevation focusing technique by reconstructing a set of uniform baselines data exploiting a light a priori information, i.e. the height sector which contains the scatterers. The validity of the method has been evaluated by carrying out simulated analyses for different scenarios.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130797052","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339424
D. Humphreys, R. T. Dickerson
This is the first report of a methodology to provide national standards traceability for EVM measurement of WCDMA RF sources using waveform metrology techniques. The method uses sampling oscilloscopes or real-time digital oscilloscopes. Preliminary results indicate that the rms uncertainty of the modulation waveform, at 95% confidence, is less than 0.3 %.
{"title":"Traceable measurement of Error Vector Magnitude (EVM) in WCDMA signals","authors":"D. Humphreys, R. T. Dickerson","doi":"10.1109/WDDC.2007.4339424","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339424","url":null,"abstract":"This is the first report of a methodology to provide national standards traceability for EVM measurement of WCDMA RF sources using waveform metrology techniques. The method uses sampling oscilloscopes or real-time digital oscilloscopes. Preliminary results indicate that the rms uncertainty of the modulation waveform, at 95% confidence, is less than 0.3 %.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117270226","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 : 2007-06-04DOI: 10.1109/WDDC.2007.4339398
D. Humphreys, M. Harper, P. Roberts
We describe a new sampling-oscilloscope based technique to measure the AM and PM components of a modulated RF signal. The method uses in-phase and quadrature referencing to simultaneously demodulate the RF signal and correct the instrument timebase nonlinearities. Preliminary results show a dynamic range of > 80 dB and agreement of better than 1% with existing methods was achieved for a 100 MHz carrier signal amplitude modulated at 20 kHz with a 50% modulation depth.
{"title":"Preliminary results for a traceable amplitude modulation measurement technique using in-phase and quadrature referencing","authors":"D. Humphreys, M. Harper, P. Roberts","doi":"10.1109/WDDC.2007.4339398","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339398","url":null,"abstract":"We describe a new sampling-oscilloscope based technique to measure the AM and PM components of a modulated RF signal. The method uses in-phase and quadrature referencing to simultaneously demodulate the RF signal and correct the instrument timebase nonlinearities. Preliminary results show a dynamic range of > 80 dB and agreement of better than 1% with existing methods was achieved for a 100 MHz carrier signal amplitude modulated at 20 kHz with a 50% modulation depth.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127815449","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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