Pub Date : 2014-10-01DOI: 10.1109/RADAR.2014.7060371
M. Amin, F. Ahmad, A. Hoorfar
We consider the problem of detection of wall back plates, which intentionally or unintentionally block electromagnetic wave penetrations and prevent the waves from reaching the indoor scene. This renders the result of through-the-wall radar imaging incorrect and misleading. The proposed approach employs squint beamforming to avoid the strong direct returns from the front side of the exterior wall and allow the diffraction for the plate placed against or near to the back side of the wall to be detected. We aid squint beamforming with a wall removal technique based on eigenstructure of the data matrix. This technique is applied prior to imaging and mitigates sidelobe wall scattering residuals, which may still obscure the relative weak plate radar return.
{"title":"Squinted array beamforming for wall back plate detection","authors":"M. Amin, F. Ahmad, A. Hoorfar","doi":"10.1109/RADAR.2014.7060371","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060371","url":null,"abstract":"We consider the problem of detection of wall back plates, which intentionally or unintentionally block electromagnetic wave penetrations and prevent the waves from reaching the indoor scene. This renders the result of through-the-wall radar imaging incorrect and misleading. The proposed approach employs squint beamforming to avoid the strong direct returns from the front side of the exterior wall and allow the diffraction for the plate placed against or near to the back side of the wall to be detected. We aid squint beamforming with a wall removal technique based on eigenstructure of the data matrix. This technique is applied prior to imaging and mitigates sidelobe wall scattering residuals, which may still obscure the relative weak plate radar return.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127739699","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060264
J. J. Strydom, J. D. de Witt, J. Cilliers
This paper describes measurements of urban ground clutter made from the CSIR campus in Pretoria, South-Africa. The measurements were made using a wideband X-band radar. The radar clutter is analysed and a Doppler spectrum based clutter model is derived. The clutter model is optimised for implementation on a digital radio frequency memory (DRFM) based hardware in the loop (HIL) radar environment simulation system. The clutter model was compared to a different measurement in the dataset and it was found to provide an accurate fit to urban ground clutter for the low grazing angles under consideration. The coherent component matched that of the data, while the slow diffuse component matched well for low clutter bandwidths of less than 1 Hz. For clutter bandwidths larger than 1 Hz there was approximately a 2 dB mismatch in the spectral tails.
{"title":"High range resolution X-band urban radar clutter model for a DRFM-based hardware in the loop radar environment simulator","authors":"J. J. Strydom, J. D. de Witt, J. Cilliers","doi":"10.1109/RADAR.2014.7060264","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060264","url":null,"abstract":"This paper describes measurements of urban ground clutter made from the CSIR campus in Pretoria, South-Africa. The measurements were made using a wideband X-band radar. The radar clutter is analysed and a Doppler spectrum based clutter model is derived. The clutter model is optimised for implementation on a digital radio frequency memory (DRFM) based hardware in the loop (HIL) radar environment simulation system. The clutter model was compared to a different measurement in the dataset and it was found to provide an accurate fit to urban ground clutter for the low grazing angles under consideration. The coherent component matched that of the data, while the slow diffuse component matched well for low clutter bandwidths of less than 1 Hz. For clutter bandwidths larger than 1 Hz there was approximately a 2 dB mismatch in the spectral tails.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121931998","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060466
B. Souissi, M. Ouarzeddine, Houda Latreche
In this paper a practical method is demonstrated for estimating terrain slopes in azimuth and ground range directions for digital elevation model (DEM) generation without any prior knowledge on the terrain by using only one single pass of polarimetric synthetic aperture radar (PolSAR) instead of two-pass or interferometric SAR (INSAR). The basic approach is by combing the orientation angle estimation and a shape-from-shading technique (SFS) which is mostly used by the computer vision community. In particular, when limited PolSAR data are available, this technique provides an alternative way for DEM generation. The polarization orientation angle (POA) is related to both the range and azimulh angles of the tilted surface and radar viewing angle and it can be estimated from the PolSAR data by using the circular polarization method which shows the best performance in computation efficiency and accuracy with respect to the other methods. After terrain slopes in both the range and azimuth directions have been estimated initially by the combination of the POA estimation and the SFS algorithm, a least squares method similar to that used in interferometric phase unwrapping is used to generate the topography. The least squares approach to phase unwrapping obtains an unwrapped solution by minimizing the differences between the discrete partial derivatives of the (wrapped) phase data and the discrete partial derivatives of the unwrapped solution. We illustrate our results by using the polarimetric SAR images acquired in Algeria by the RadarSAT2 (FQ19) in C-band.
{"title":"Estimation of surface topography from single polarimetric SAR imagery using RADARSAT2","authors":"B. Souissi, M. Ouarzeddine, Houda Latreche","doi":"10.1109/RADAR.2014.7060466","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060466","url":null,"abstract":"In this paper a practical method is demonstrated for estimating terrain slopes in azimuth and ground range directions for digital elevation model (DEM) generation without any prior knowledge on the terrain by using only one single pass of polarimetric synthetic aperture radar (PolSAR) instead of two-pass or interferometric SAR (INSAR). The basic approach is by combing the orientation angle estimation and a shape-from-shading technique (SFS) which is mostly used by the computer vision community. In particular, when limited PolSAR data are available, this technique provides an alternative way for DEM generation. The polarization orientation angle (POA) is related to both the range and azimulh angles of the tilted surface and radar viewing angle and it can be estimated from the PolSAR data by using the circular polarization method which shows the best performance in computation efficiency and accuracy with respect to the other methods. After terrain slopes in both the range and azimuth directions have been estimated initially by the combination of the POA estimation and the SFS algorithm, a least squares method similar to that used in interferometric phase unwrapping is used to generate the topography. The least squares approach to phase unwrapping obtains an unwrapped solution by minimizing the differences between the discrete partial derivatives of the (wrapped) phase data and the discrete partial derivatives of the unwrapped solution. We illustrate our results by using the polarimetric SAR images acquired in Algeria by the RadarSAT2 (FQ19) in C-band.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125799125","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060265
H. Wheelwright, W. Wallace, W. Dawber, D. Manson
This article examines the assessment of propagation conditions using data from a state-of-the-art, multi-function radar, namely the advanced radar technology integrated system testbed (ARTIST). The radar was situated at Wallops Island, USA and an extensive series of clutter recordings was conducted in 2010. The recordings are compared to site specific modelling using the naval electromagnetic environmental simulation suite (NEMESiS) software. Using this modelling software, it is shown that refractivity profiles predicted using local environmental measurements, in conjunction with analytical descriptions of evaporation ducts, do not result in a high fidelity reproduction of the clutter observed. Refractivity profiles recorded with radiosondes result in a better match to the data, but can produce an over-prediction of clutter. It is concluded that the most robust way to accurately assess propagation conditions is through a direct analysis of the radar clutter data, in conjunction with detailed modelling. This approach, duct inversion, is explored and is shown to have the potential of providing a quasi-real time assessment of propagation conditions, as required for environmentally aware radar.
{"title":"Investigation of radar propagation prediction methods using ARTIST data","authors":"H. Wheelwright, W. Wallace, W. Dawber, D. Manson","doi":"10.1109/RADAR.2014.7060265","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060265","url":null,"abstract":"This article examines the assessment of propagation conditions using data from a state-of-the-art, multi-function radar, namely the advanced radar technology integrated system testbed (ARTIST). The radar was situated at Wallops Island, USA and an extensive series of clutter recordings was conducted in 2010. The recordings are compared to site specific modelling using the naval electromagnetic environmental simulation suite (NEMESiS) software. Using this modelling software, it is shown that refractivity profiles predicted using local environmental measurements, in conjunction with analytical descriptions of evaporation ducts, do not result in a high fidelity reproduction of the clutter observed. Refractivity profiles recorded with radiosondes result in a better match to the data, but can produce an over-prediction of clutter. It is concluded that the most robust way to accurately assess propagation conditions is through a direct analysis of the radar clutter data, in conjunction with detailed modelling. This approach, duct inversion, is explored and is shown to have the potential of providing a quasi-real time assessment of propagation conditions, as required for environmentally aware radar.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"165 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127306494","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060416
J. Euziére, R. Guinvarc’h, M. Lesturgie, B. Uguen, R. Gillard
This paper introduces the use of Time-modulated array methods to realize a dual function array. It is able to do a radar function in the mainlobe, while realizing a communication in the side lobe.
本文介绍了利用时调制阵列的方法来实现双功能阵列。它可以在主瓣中实现雷达功能，在副瓣中实现通信功能。
{"title":"Dual function radar communication Time-modulated array","authors":"J. Euziére, R. Guinvarc’h, M. Lesturgie, B. Uguen, R. Gillard","doi":"10.1109/RADAR.2014.7060416","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060416","url":null,"abstract":"This paper introduces the use of Time-modulated array methods to realize a dual function array. It is able to do a radar function in the mainlobe, while realizing a communication in the side lobe.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"64 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132791148","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060243
Stefan Brisken
This paper is concerned with recent and future developments in the field of multistatic radar imaging of moving targets. It briefly reviews traditional monostatic ISAR imaging and identifies its drawbacks. We then present ideas, some of them have meanwhile been verified in experiments, how a multistatic setup can overcome some of these problems. Clearly, a multistatic setup leads to increased complexity and new problems. We display these new problems and present approaches to solve some of them. We use mind maps to illustrate the context. Multichannel techniques like interferometric or polarimetric ISAR are out of the scope of this paper.
{"title":"Multistatic ISAR - chances and challenges","authors":"Stefan Brisken","doi":"10.1109/RADAR.2014.7060243","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060243","url":null,"abstract":"This paper is concerned with recent and future developments in the field of multistatic radar imaging of moving targets. It briefly reviews traditional monostatic ISAR imaging and identifies its drawbacks. We then present ideas, some of them have meanwhile been verified in experiments, how a multistatic setup can overcome some of these problems. Clearly, a multistatic setup leads to increased complexity and new problems. We display these new problems and present approaches to solve some of them. We use mind maps to illustrate the context. Multichannel techniques like interferometric or polarimetric ISAR are out of the scope of this paper.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128596676","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060354
L. Ulander, A. Gustavsson, T. Jonsson, R. Ragnarsson, G. Stenstrom
The paper presents results from developing and testing a bistatic SAR system for ground surveillance in the VHF band (25-83 MHz). It is based on two radars developed by FOI: The monostatic LORA system installed in an aircraft and the bistatic and passive CARINA system installed on a helicopter. CARINA is based on direct RF sampling of two receiver channels (2 × 14 bits @ 250 MSPS) together with continuous non-interrupted data storage capability. The system has recently been developed by FOI and is described in detail. System architecture, installation in the helicopter platform and results from early trials in bistatic SAR mode are described. Results show forest clutter can be significantly reduced in bistatic SAR geometries compared to the signature of a small truck (van).
{"title":"Development of CARINA bistatic VHF-band SAR","authors":"L. Ulander, A. Gustavsson, T. Jonsson, R. Ragnarsson, G. Stenstrom","doi":"10.1109/RADAR.2014.7060354","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060354","url":null,"abstract":"The paper presents results from developing and testing a bistatic SAR system for ground surveillance in the VHF band (25-83 MHz). It is based on two radars developed by FOI: The monostatic LORA system installed in an aircraft and the bistatic and passive CARINA system installed on a helicopter. CARINA is based on direct RF sampling of two receiver channels (2 × 14 bits @ 250 MSPS) together with continuous non-interrupted data storage capability. The system has recently been developed by FOI and is described in detail. System architecture, installation in the helicopter platform and results from early trials in bistatic SAR mode are described. Results show forest clutter can be significantly reduced in bistatic SAR geometries compared to the signature of a small truck (van).","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116832112","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060423
Peter R. Drake, J. Bourgeois, A. Hopf, Francis Lok, D. McLaughlin
A Raytheon-developed dual polarization X-band active phased array radar has been designed and is being tested for use as a multi-mission, weather and surveillance, radar. The radar is optimized for integration into existing networks with the capability of being deployed on existing telecom, turbine or building infrastructures. The partnership between Raytheon and CASA brings together years of expertise to meet future requirements of en route and terminal air surveillance and weather remote sensing. This paper provides an update to this Raytheon dual polarization active phased array radar technology.
{"title":"Dual-polarization X-band phased array weather radar: Technology update","authors":"Peter R. Drake, J. Bourgeois, A. Hopf, Francis Lok, D. McLaughlin","doi":"10.1109/RADAR.2014.7060423","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060423","url":null,"abstract":"A Raytheon-developed dual polarization X-band active phased array radar has been designed and is being tested for use as a multi-mission, weather and surveillance, radar. The radar is optimized for integration into existing networks with the capability of being deployed on existing telecom, turbine or building infrastructures. The partnership between Raytheon and CASA brings together years of expertise to meet future requirements of en route and terminal air surveillance and weather remote sensing. This paper provides an update to this Raytheon dual polarization active phased array radar technology.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117126247","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060267
Yufang Tang, Xueming Li, Yan Xu, Shuchang Liu, Shuxin Ouyang
Many of the most successful classifiers are based on convex surrogate loss functions. However, it is widely accepted that the 0 - 1 loss would be more natural for classification performance evaluation and many surrogate loss functions can be understood as convex approximations to the 0 - 1 loss. Therefore, in this paper, we attempt to minimize the 0 - 1 loss directly via Mixed Integer Programming and a maximum margin 0 - 1 loss is presented. To test the performance of the proposed loss measurement, two maximum margin 0 - 1 loss classifiers are implemented for binary classification and semi-supervised classification respectively. According to the experiment results of the publicly available UCI datasets, the maximum margin 0 - 1 loss approach has achieved superior performance. Meanwhile, in term of computational efficiency, with the rapid development of Mixed Integer Programming in recent years, the state-of-art solvers can output the global optimum solution of the proposed approach in seconds when the number of training instances N and the dimension of feature space D are relatively small (Empirically N ≤ 100, D ≤ 20). Therefore, it can already be adopted to solve small-scale classification problems in the real world.
{"title":"A Mixed Integer Programming approach to maximum margin 0 – 1 loss classification","authors":"Yufang Tang, Xueming Li, Yan Xu, Shuchang Liu, Shuxin Ouyang","doi":"10.1109/RADAR.2014.7060267","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060267","url":null,"abstract":"Many of the most successful classifiers are based on convex surrogate loss functions. However, it is widely accepted that the 0 - 1 loss would be more natural for classification performance evaluation and many surrogate loss functions can be understood as convex approximations to the 0 - 1 loss. Therefore, in this paper, we attempt to minimize the 0 - 1 loss directly via Mixed Integer Programming and a maximum margin 0 - 1 loss is presented. To test the performance of the proposed loss measurement, two maximum margin 0 - 1 loss classifiers are implemented for binary classification and semi-supervised classification respectively. According to the experiment results of the publicly available UCI datasets, the maximum margin 0 - 1 loss approach has achieved superior performance. Meanwhile, in term of computational efficiency, with the rapid development of Mixed Integer Programming in recent years, the state-of-art solvers can output the global optimum solution of the proposed approach in seconds when the number of training instances N and the dimension of feature space D are relatively small (Empirically N ≤ 100, D ≤ 20). Therefore, it can already be adopted to solve small-scale classification problems in the real world.","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114319415","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 : 2014-10-01DOI: 10.1109/RADAR.2014.7060310
H. Ghanmi, A. Khenchaf, F. Comblet
The aim of this paper is to study the influence of the pollutants (oil spills) on the electromagnetic signature of sea surface observed in bistatic configuration. Therefore, we will start the numerical analyses of the pollutants influence on the sea surface roughness. Then, we will evaluate the electromagnetic scattering coefficients of the contaminated sea surface (sea surface covered by oil layer) in bistatic case by using the numerical Forward-Backward Method (FBM). The model used for the numerical simulation of bistatic scattering coefficients of clean and contaminated sea surface has been analyzed as a function of various parameters (sea state, type of pollutant, incidence and observation angles, radar frequency and polarizations).
{"title":"Numerical simulation of bistatic electromagnetic scattering by contaminated sea surface","authors":"H. Ghanmi, A. Khenchaf, F. Comblet","doi":"10.1109/RADAR.2014.7060310","DOIUrl":"https://doi.org/10.1109/RADAR.2014.7060310","url":null,"abstract":"The aim of this paper is to study the influence of the pollutants (oil spills) on the electromagnetic signature of sea surface observed in bistatic configuration. Therefore, we will start the numerical analyses of the pollutants influence on the sea surface roughness. Then, we will evaluate the electromagnetic scattering coefficients of the contaminated sea surface (sea surface covered by oil layer) in bistatic case by using the numerical Forward-Backward Method (FBM). The model used for the numerical simulation of bistatic scattering coefficients of clean and contaminated sea surface has been analyzed as a function of various parameters (sea state, type of pollutant, incidence and observation angles, radar frequency and polarizations).","PeriodicalId":317910,"journal":{"name":"2014 International Radar Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115340928","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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