Pub Date : 2007-06-04DOI: 10.1109/WDDC.2007.4339402
M. Lipardi, D. Mattera, F. Sterle
The wide spread of low-cost fabrication technologies gives rise to unpredictable imperfections associated with the analog stages which perform the frequency conversion. More specifically, it is well known that such stages suffer from the in-phase (I) and quadrature (Q) imbalance. In this paper, with reference to a single-carrier time-dispersive noisy channel, we address the receiver design when both the transmitter and the receiver are affected by the IQ imbalance, and we propose to resort to the widely linear filtering in order to improve the performances of the conventional minimum mean square error (MMSE) linear equalizer. The results show that the adoption of WL filters allows one to achieve considerable gains both in terms of MMSE and symbol error rate, with a limited increase in the computational complexity of the equalization stage.
{"title":"MMSE equalization in presence of transmitter and receiver IQ imbalance","authors":"M. Lipardi, D. Mattera, F. Sterle","doi":"10.1109/WDDC.2007.4339402","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339402","url":null,"abstract":"The wide spread of low-cost fabrication technologies gives rise to unpredictable imperfections associated with the analog stages which perform the frequency conversion. More specifically, it is well known that such stages suffer from the in-phase (I) and quadrature (Q) imbalance. In this paper, with reference to a single-carrier time-dispersive noisy channel, we address the receiver design when both the transmitter and the receiver are affected by the IQ imbalance, and we propose to resort to the widely linear filtering in order to improve the performances of the conventional minimum mean square error (MMSE) linear equalizer. The results show that the adoption of WL filters allows one to achieve considerable gains both in terms of MMSE and symbol error rate, with a limited increase in the computational complexity of the equalization stage.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115482615","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.2007.4339390
B. Jung, J. Chun, R. Adve, Jonghoon Chun
This paper presents the hybrid algorithm of SigmaDelta-STAP and direct data domain(D3) which is robust to the discrete interferer. SigmaDelta-STAP provides high performance result with the relatively low complexity of calculation. It also requires small number of training sample to estimate covariance matrix. However this algorithm is vulnerable to the discrete interferer which is target-like interferer with high SNR. This paper shows that SigmaDelta-STAP can suppress discrete interferer signal in conjunction with direct data domain (D3) method which is an effective method to eliminate non-correlated interference such as discrete interferer in the non-homogeneous environment.
提出了一种对离散干扰具有鲁棒性的SigmaDelta-STAP和直接数据域(D3)混合算法。SigmaDelta-STAP以相对较低的计算复杂度提供了高性能的结果。估计协方差矩阵也需要少量的训练样本。但该算法容易受到高信噪比类目标干扰的干扰。研究表明，SigmaDelta-STAP与直接数据域(direct data domain, D3)方法结合可以抑制离散干扰信号，是一种在非均匀环境下消除离散干扰等非相关干扰的有效方法。
{"title":"Discrete Suppression with ΣΔ-STAP","authors":"B. Jung, J. Chun, R. Adve, Jonghoon Chun","doi":"10.1109/WDDC.2007.4339390","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339390","url":null,"abstract":"This paper presents the hybrid algorithm of SigmaDelta-STAP and direct data domain(D3) which is robust to the discrete interferer. SigmaDelta-STAP provides high performance result with the relatively low complexity of calculation. It also requires small number of training sample to estimate covariance matrix. However this algorithm is vulnerable to the discrete interferer which is target-like interferer with high SNR. This paper shows that SigmaDelta-STAP can suppress discrete interferer signal in conjunction with direct data domain (D3) method which is an effective method to eliminate non-correlated interference such as discrete interferer in the non-homogeneous environment.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114378515","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.2007.4339418
I. Demirkiran, D. Weiner, A. Drozd
A design technique for reducing in-band intermodulation products caused by adjacent channel signals is presented. The technique makes use of the fact that certain in-band nonlinear responses depend upon the out-of-band linear behavior of the network. The concept is illustrated by means of a simple example.
{"title":"An approach for reduction of in-band intermodulation products caused by adjacent channel signals","authors":"I. Demirkiran, D. Weiner, A. Drozd","doi":"10.1109/WDDC.2007.4339418","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339418","url":null,"abstract":"A design technique for reducing in-band intermodulation products caused by adjacent channel signals is presented. The technique makes use of the fact that certain in-band nonlinear responses depend upon the out-of-band linear behavior of the network. The concept is illustrated by means of a simple example.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130245806","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.2007.4339385
K. Magde, M. Wicks
Distributed sensing systems incorporating RF tomography allow a trade-off between spatial and spectral diversity, however a large number of widely spaced sensors is conventionally thought to be required. A practical method of reducing the number of sensor nodes is introduced via the concept of the virtual tomographic array. Furthermore, the geometry of this virtual array is electronically reconfigurable. Optimal resource allocation is accomplished instantaneously, with dynamic control based upon matching sensing modalities to site specific target and clutter observables.
{"title":"Waveforms in virtual tomographic arrays","authors":"K. Magde, M. Wicks","doi":"10.1109/WDDC.2007.4339385","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339385","url":null,"abstract":"Distributed sensing systems incorporating RF tomography allow a trade-off between spatial and spectral diversity, however a large number of widely spaced sensors is conventionally thought to be required. A practical method of reducing the number of sensor nodes is introduced via the concept of the virtual tomographic array. Furthermore, the geometry of this virtual array is electronically reconfigurable. Optimal resource allocation is accomplished instantaneously, with dynamic control based upon matching sensing modalities to site specific target and clutter observables.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115254983","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.2007.4339404
D. Bellido, J. T. Entrambasaguas
In this work the evaluation of LS channel estimation algorithm for MIMO-OFDM system is carried out. The evaluation has been made using specific pilot design rules that guarantee a bounded error level for the estimation. The method is used to estimate the channel matrix. The quality of the method is evaluated, not for a specific channel but in diverse surroundings of mobile representative channels with different characteristics (SUI channels). The evaluation has been made by software simulations and system parameters complying 802.16 standard. Estimation error dependence on the number of pilots used, its design parameters and SNR are obtained.
{"title":"MSE evaluation at reception end in MIMO-OFDM systems using LS channel estimation","authors":"D. Bellido, J. T. Entrambasaguas","doi":"10.1109/WDDC.2007.4339404","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339404","url":null,"abstract":"In this work the evaluation of LS channel estimation algorithm for MIMO-OFDM system is carried out. The evaluation has been made using specific pilot design rules that guarantee a bounded error level for the estimation. The method is used to estimate the channel matrix. The quality of the method is evaluated, not for a specific channel but in diverse surroundings of mobile representative channels with different characteristics (SUI channels). The evaluation has been made by software simulations and system parameters complying 802.16 standard. Estimation error dependence on the number of pilots used, its design parameters and SNR are obtained.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121966893","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.2007.4339417
M. Wicks, W. Moore
One can easily envision future military operations and emerging civilian requirements (e.g. intelligent unmanned vehicles for urban warfare, intelligent manufacturing plants) that will be both complex and stressing and will demand innovative sensors and sensor configurations. The goal of our research into distributed and layered sensing is to develop a cost effective and extendable approach for providing surveillance for a variety of applications in dynamically changing military and civilian environments. Within distributed and layered sensing, we foresee a new sensor archetype. In this paradigm, sensors and algorithms will be autonomously altered depending on the environment. Radars will use the same returns to perform detection and discrimination, to adjust the platform flight path and change mission priorities. The sensors will dynamically and automatically change waveform parameters to accomplish these goals. Disparate sensors will communicate and share data and instructions in real-time. Intelligent sensor systems will operate within and between sensor platforms such that the integration of multiple sensor data provides information needed to achieve dynamic goals and avoid electromagnetic fratricide. Intelligent sensor platforms working in partnership will increase information flow, minimize ambiguities, and dynamically change multiple sensors' operations based upon a changing environment. Concomitant with the current emphasis on more flexible defense structures, distributed and layered sensing will allow the appropriate incremental application of remote sensing assets by matching resources to the situation at hand. In this paper, we discuss the electromagnetic compatibility (EMC) issues that must be addressed and understood as part of the development of a futuristic intelligence, surveillance and reconnaissance concept utilizing distributed and layered sensing waveform diverse systems. These systems involve the innovative integration of cutting edge technologies such as: knowledge-based signal processing, robotics, wireless networking waveform diversity, the semantic web, advanced computer architectures and supporting software languages. This concept is projected as an autonomous constellation of air, space, and ground vehicles that would offer a robust paradigm to build toward future deployments. The goal is to develop waveform-time-space adaptive processing for distributed apertures that could reduce EMC issues.
{"title":"Distributed and Layered Sensing","authors":"M. Wicks, W. Moore","doi":"10.1109/WDDC.2007.4339417","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339417","url":null,"abstract":"One can easily envision future military operations and emerging civilian requirements (e.g. intelligent unmanned vehicles for urban warfare, intelligent manufacturing plants) that will be both complex and stressing and will demand innovative sensors and sensor configurations. The goal of our research into distributed and layered sensing is to develop a cost effective and extendable approach for providing surveillance for a variety of applications in dynamically changing military and civilian environments. Within distributed and layered sensing, we foresee a new sensor archetype. In this paradigm, sensors and algorithms will be autonomously altered depending on the environment. Radars will use the same returns to perform detection and discrimination, to adjust the platform flight path and change mission priorities. The sensors will dynamically and automatically change waveform parameters to accomplish these goals. Disparate sensors will communicate and share data and instructions in real-time. Intelligent sensor systems will operate within and between sensor platforms such that the integration of multiple sensor data provides information needed to achieve dynamic goals and avoid electromagnetic fratricide. Intelligent sensor platforms working in partnership will increase information flow, minimize ambiguities, and dynamically change multiple sensors' operations based upon a changing environment. Concomitant with the current emphasis on more flexible defense structures, distributed and layered sensing will allow the appropriate incremental application of remote sensing assets by matching resources to the situation at hand. In this paper, we discuss the electromagnetic compatibility (EMC) issues that must be addressed and understood as part of the development of a futuristic intelligence, surveillance and reconnaissance concept utilizing distributed and layered sensing waveform diverse systems. These systems involve the innovative integration of cutting edge technologies such as: knowledge-based signal processing, robotics, wireless networking waveform diversity, the semantic web, advanced computer architectures and supporting software languages. This concept is projected as an autonomous constellation of air, space, and ground vehicles that would offer a robust paradigm to build toward future deployments. The goal is to develop waveform-time-space adaptive processing for distributed apertures that could reduce EMC issues.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122423755","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.2007.4339372
F. Soldani, C. Alabaster
This paper compares the radar detection performance of a narrow band rectangular pulse, linear chirp and nonlinear stepped frequency waveform approximating to a matched target illumination against two target types (a farm tractor and a main battle tank) in the presence of clutter (soil/sand, rocks and woodland).
{"title":"The benefits of matched illumination for radar detection of ground based targets","authors":"F. Soldani, C. Alabaster","doi":"10.1109/WDDC.2007.4339372","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339372","url":null,"abstract":"This paper compares the radar detection performance of a narrow band rectangular pulse, linear chirp and nonlinear stepped frequency waveform approximating to a matched target illumination against two target types (a farm tractor and a main battle tank) in the presence of clutter (soil/sand, rocks and woodland).","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"52 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123459656","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.2007.4339429
Junghyo Kim, A. Ossowska, W. Wiesbeck
Digital beamforming (DBF) technique is a promising technique for future Synthetic Aperture Radar (SAR). In this paper, we present the preliminary experiments and investigate the crucial parameters for the optimization of the DBF SAR. The measurements were accomplished by a ground-based DBF SAR system for a single target. The demonstrator provides the raw data including the system response. SAR images were reconstructed with numerous spatial sampling distances, not only by DBF SAR processing, but also conventional mono-static SAR processing. The reconstructed images show that the minimum variation of the phase between the receive channel is crucial to obtain the theoretical improvement factor and achieve the wide area observation with fine resolution.
{"title":"Laboratory experiments for the evaluation of Digital Beamforming SAR features","authors":"Junghyo Kim, A. Ossowska, W. Wiesbeck","doi":"10.1109/WDDC.2007.4339429","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339429","url":null,"abstract":"Digital beamforming (DBF) technique is a promising technique for future Synthetic Aperture Radar (SAR). In this paper, we present the preliminary experiments and investigate the crucial parameters for the optimization of the DBF SAR. The measurements were accomplished by a ground-based DBF SAR system for a single target. The demonstrator provides the raw data including the system response. SAR images were reconstructed with numerous spatial sampling distances, not only by DBF SAR processing, but also conventional mono-static SAR processing. The reconstructed images show that the minimum variation of the phase between the receive channel is crucial to obtain the theoretical improvement factor and achieve the wide area observation with fine resolution.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127711302","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.2007.4339381
M. Forouzanfar, H. Moghaddam
A complex wavelet-based Bayesian method is proposed for denoising of medical ultrasound images. The symmetric alpha-stable distribution (SaS) is used to model the real and imaginary parts of the complex wavelet coefficients of logarithmically transformed noise-free images. The coefficients that correspond to the noise are assumed to approximate a Gaussian distribution. These models are then exploited to develop a Bayesian maximum a posteriori (MAP) estimator, which is well defined for all SaS random variables. To estimate the wavelet coefficients statistics precisely and adaptively, we classify the wavelet coefficients into different clusters using context modeling, which exploits the intrascale dependency of wavelet coefficients. The simulations demonstrate an improved denoising performance over some related earlier techniques.
{"title":"Ultrasound speckle suppression using heavy-tailed distributions in the dual-tree complex wavelet domain","authors":"M. Forouzanfar, H. Moghaddam","doi":"10.1109/WDDC.2007.4339381","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339381","url":null,"abstract":"A complex wavelet-based Bayesian method is proposed for denoising of medical ultrasound images. The symmetric alpha-stable distribution (SaS) is used to model the real and imaginary parts of the complex wavelet coefficients of logarithmically transformed noise-free images. The coefficients that correspond to the noise are assumed to approximate a Gaussian distribution. These models are then exploited to develop a Bayesian maximum a posteriori (MAP) estimator, which is well defined for all SaS random variables. To estimate the wavelet coefficients statistics precisely and adaptively, we classify the wavelet coefficients into different clusters using context modeling, which exploits the intrascale dependency of wavelet coefficients. The simulations demonstrate an improved denoising performance over some related earlier techniques.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115532506","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.2007.4339456
M. Gabele, I. Sikaneta
Two-channel SAR-GMTI systems are suboptimal for moving target motion parameter estimation. Indeed, the ATI phase estimate of the across-track velocity component for a moving target is biased to lower values depending on the target signal to clutter ratio and the target across-track velocity. Additional antenna diversity can introduce additional degrees of freedom that can eliminate the bias problem. Aperture switching is an accepted method to virtually increase the number of channels without adding new hardware. One such mode is the RADARSAT-2 toggle mode (S. Chiu and C. Gierull, 2006). This paper proposes a new processing method to create a similar effective phase center configuration as the RADARSAT-2 Toggle mode from already recorded two-channel SAR data. This is achieved by delaying and combining the recorded two-channel measurements. The combination operation manifests not only a third phase center halfway between the phase centers of the two-channel system, but also a different antenna length of the virtual third antenna which requires a modification of the DPCA-ATI processing algorithm. The DPCA-ATI performance of the new mode is assessed and compared to ATI from the original two-channel mode.
{"title":"A new method to create a virtual third antenna from a two-channel SAR-GMTI system","authors":"M. Gabele, I. Sikaneta","doi":"10.1109/WDDC.2007.4339456","DOIUrl":"https://doi.org/10.1109/WDDC.2007.4339456","url":null,"abstract":"Two-channel SAR-GMTI systems are suboptimal for moving target motion parameter estimation. Indeed, the ATI phase estimate of the across-track velocity component for a moving target is biased to lower values depending on the target signal to clutter ratio and the target across-track velocity. Additional antenna diversity can introduce additional degrees of freedom that can eliminate the bias problem. Aperture switching is an accepted method to virtually increase the number of channels without adding new hardware. One such mode is the RADARSAT-2 toggle mode (S. Chiu and C. Gierull, 2006). This paper proposes a new processing method to create a similar effective phase center configuration as the RADARSAT-2 Toggle mode from already recorded two-channel SAR data. This is achieved by delaying and combining the recorded two-channel measurements. The combination operation manifests not only a third phase center halfway between the phase centers of the two-channel system, but also a different antenna length of the virtual third antenna which requires a modification of the DPCA-ATI processing algorithm. The DPCA-ATI performance of the new mode is assessed and compared to ATI from the original two-channel mode.","PeriodicalId":142822,"journal":{"name":"2007 International Waveform Diversity and Design Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124358184","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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