Pub Date : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396742
D. Burger, S. Tenbohlen, W. Kohler, W. Ebbinghaus
Switching operations in the primary circuits of medium voltage switchgears are mostly attended by discharge processes in terms of pre- and restrikes between the switch contacts. Due to their high amplitudes as well as their steep wave fronts, such discharges are known to be very broadband and severe sources of electromagnetic disturbance. This contribution deals with the origin and the consequences of repetitively occurring electromagnetic disturbance pulses due to multiple restrikes at vacuum circuit breakers. On the basis of measurements at a special switchgear test setup, the impact of multiple restrikes at vacuum circuit breakers on the EMC of the switchgear installation is analyzed in time and frequency domain. Based on the results, the severity of multiple restrikes is estimated by comparing the disturbance values with conventional (well known) switching disturbances like during disconnector operations. Finally, some approaches for the handling of multiple restrikes at vacuum circuit breakers with respect to the EMC aspects are given in the summary.
{"title":"Impact of multiple restrikes at vacuum circuit breakers on the EMC of medium voltage switchgear","authors":"D. Burger, S. Tenbohlen, W. Kohler, W. Ebbinghaus","doi":"10.1109/EMCEUROPE.2012.6396742","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396742","url":null,"abstract":"Switching operations in the primary circuits of medium voltage switchgears are mostly attended by discharge processes in terms of pre- and restrikes between the switch contacts. Due to their high amplitudes as well as their steep wave fronts, such discharges are known to be very broadband and severe sources of electromagnetic disturbance. This contribution deals with the origin and the consequences of repetitively occurring electromagnetic disturbance pulses due to multiple restrikes at vacuum circuit breakers. On the basis of measurements at a special switchgear test setup, the impact of multiple restrikes at vacuum circuit breakers on the EMC of the switchgear installation is analyzed in time and frequency domain. Based on the results, the severity of multiple restrikes is estimated by comparing the disturbance values with conventional (well known) switching disturbances like during disconnector operations. Finally, some approaches for the handling of multiple restrikes at vacuum circuit breakers with respect to the EMC aspects are given in the summary.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133498545","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396923
M. Kowal, S. Kubal, P. Piotrowski, R. Zielinski
The main goal of this paper is an analysis of the vulnerability of radiocommunication systems operating in the 24-29GHz band against the interference from other systems operating in this band. Analysis was focused on Short Range Radars and Fixed Service. Short characteristic of both systems, calculation method, scenarios of interference and simulation results were shown.
{"title":"Compatibility study between short range radars and fixed service operating in 24GHz band — selected aspects","authors":"M. Kowal, S. Kubal, P. Piotrowski, R. Zielinski","doi":"10.1109/EMCEUROPE.2012.6396923","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396923","url":null,"abstract":"The main goal of this paper is an analysis of the vulnerability of radiocommunication systems operating in the 24-29GHz band against the interference from other systems operating in this band. Analysis was focused on Short Range Radars and Fixed Service. Short characteristic of both systems, calculation method, scenarios of interference and simulation results were shown.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"73 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133652201","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396791
P. Arcuti, G. Monti, L. Tarricone, L. Sileo, L. Martiradonna, M. De Vittorio
This paper presents a novel biotelemetry system based on a fully-passive architecture; High Electron Mobility Transistors are used as sensing elements. The main advantages and drawbacks related to the approach here proposed are deeply analyzed and some possible solutions identified. Furthermore, some preliminary experimental results are given and discussed.
{"title":"A novel biotelemetry system to monitor human vital signs","authors":"P. Arcuti, G. Monti, L. Tarricone, L. Sileo, L. Martiradonna, M. De Vittorio","doi":"10.1109/EMCEUROPE.2012.6396791","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396791","url":null,"abstract":"This paper presents a novel biotelemetry system based on a fully-passive architecture; High Electron Mobility Transistors are used as sensing elements. The main advantages and drawbacks related to the approach here proposed are deeply analyzed and some possible solutions identified. Furthermore, some preliminary experimental results are given and discussed.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133955276","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396817
S. Wielandt, D. Mercy, N. Stevens, L. De Strycker, Jean-Pierre Goemaere
When RFID reader antennas are placed in a parallel line configuration, proper shielding is indispensable to prevent the readout of tags in a different line. However, placing electrically conductive or magnetically permeable shielding materials in the vicinity of a loop antenna influences the magnetic field strength and self inductance of the antenna, thus affecting the readout range. This paper evaluates the effects of different shieldings on the magnetic field strength, the readout range of an RFID tag and the self inductance of the antenna. The considered shieldings consist of copper or a combination of copper with a layer of highly or lowly permeable ferrite on top. First, the influences of these materials are compared to a free space setup in FEM simulations. These results are subsequently verified in an experimental setup. The configuration with a copper plate covered with a highly permeable ferrite layer increases the magnetic field strength, readout range and self inductance of the antenna, in contrast to the other configurations. Due to the efficient shielding, erroneous readout events of tags in a parallel line are suppressed.
{"title":"Evaluation of shielding materials for low frequency RFID systems","authors":"S. Wielandt, D. Mercy, N. Stevens, L. De Strycker, Jean-Pierre Goemaere","doi":"10.1109/EMCEUROPE.2012.6396817","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396817","url":null,"abstract":"When RFID reader antennas are placed in a parallel line configuration, proper shielding is indispensable to prevent the readout of tags in a different line. However, placing electrically conductive or magnetically permeable shielding materials in the vicinity of a loop antenna influences the magnetic field strength and self inductance of the antenna, thus affecting the readout range. This paper evaluates the effects of different shieldings on the magnetic field strength, the readout range of an RFID tag and the self inductance of the antenna. The considered shieldings consist of copper or a combination of copper with a layer of highly or lowly permeable ferrite on top. First, the influences of these materials are compared to a free space setup in FEM simulations. These results are subsequently verified in an experimental setup. The configuration with a copper plate covered with a highly permeable ferrite layer increases the magnetic field strength, readout range and self inductance of the antenna, in contrast to the other configurations. Due to the efficient shielding, erroneous readout events of tags in a parallel line are suppressed.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131816429","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396727
T. Nakayama, D. Kitagawa, M. Ishii, Y. Saito
In the consumer electronics field, the clock frequency of the system LSI (large-scale integration) is increasing significantly. To maintain operational stability, the impedance of the power distribution network, especially in the high frequency range, has to be reduced. This results in increased number of power supply or ground pins for an LSI package. The increased pin count will require a larger LSI package leading to a cost increase. In order to reduce costs, the number and placement of the power supply pins and ground pins have to be optimized and hence, the current on each power supply pins and ground pin should be monitored. We are therefore developing a new probe using a printed circuit board with embedded parts to monitor the high frequency current of each pin in a ball grid array (BGA) package. In this paper, we report on the structure of the new probe and its high-frequency current measurement results.
{"title":"Proposal of a current measurement technique for each pin of a BGA package","authors":"T. Nakayama, D. Kitagawa, M. Ishii, Y. Saito","doi":"10.1109/EMCEUROPE.2012.6396727","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396727","url":null,"abstract":"In the consumer electronics field, the clock frequency of the system LSI (large-scale integration) is increasing significantly. To maintain operational stability, the impedance of the power distribution network, especially in the high frequency range, has to be reduced. This results in increased number of power supply or ground pins for an LSI package. The increased pin count will require a larger LSI package leading to a cost increase. In order to reduce costs, the number and placement of the power supply pins and ground pins have to be optimized and hence, the current on each power supply pins and ground pin should be monitored. We are therefore developing a new probe using a printed circuit board with embedded parts to monitor the high frequency current of each pin in a ball grid array (BGA) package. In this paper, we report on the structure of the new probe and its high-frequency current measurement results.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134184135","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396929
M. Nakayama, T. Kobayashi
A simple equation for calculating electric field strength has been widely used for electromagnetic applications. This equation has also been applied to the calibration of electric field probes, which has been specified in various standards, such as ISO/TR 10305-1, ISO/TR 10305-2, and IEEE Std. 1309. It is, however, valid only in the far field region. It is well known that the far field distance is given by λ/2π, where λ is the wavelength. This formula, however, gives a distance where the magnitudes of three terms - electrostatic, induction, and radiation fields - are equal. The lowest test frequency specified in ISO 11452-2 is 80 MHz (λ = 3.75 m) and the test distance is 1 m, which slightly exceeds λ/2π. The accuracy attained by the conventional equation deteriorates at this marginal distance. In this report, a new equation for calculating the electric field strength is proposed, embracing the effects of variations in space impedance. Numerical results yielded by the conventional and proposed equations were compared with the experimental data measured in a radio anechoic chamber. Substantial improvement in accuracy was achieved with the proposed equation.
{"title":"Electric field strength estimation in boundary region between near and far fields","authors":"M. Nakayama, T. Kobayashi","doi":"10.1109/EMCEUROPE.2012.6396929","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396929","url":null,"abstract":"A simple equation for calculating electric field strength has been widely used for electromagnetic applications. This equation has also been applied to the calibration of electric field probes, which has been specified in various standards, such as ISO/TR 10305-1, ISO/TR 10305-2, and IEEE Std. 1309. It is, however, valid only in the far field region. It is well known that the far field distance is given by λ/2π, where λ is the wavelength. This formula, however, gives a distance where the magnitudes of three terms - electrostatic, induction, and radiation fields - are equal. The lowest test frequency specified in ISO 11452-2 is 80 MHz (λ = 3.75 m) and the test distance is 1 m, which slightly exceeds λ/2π. The accuracy attained by the conventional equation deteriorates at this marginal distance. In this report, a new equation for calculating the electric field strength is proposed, embracing the effects of variations in space impedance. Numerical results yielded by the conventional and proposed equations were compared with the experimental data measured in a radio anechoic chamber. Substantial improvement in accuracy was achieved with the proposed equation.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134473606","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396754
F. Nieden, Stanislav Scheier, Stephan Frei
Accurate and flexible modeling of field coupling from ESD sources to cables or PCB traces (indirect ESD) is important for immunity estimations. Accurate circuit models can be obtained by applying approximations techniques to measurement data in frequency domain. In this paper an accurate ESD generator model is extended to model ESD coupling behavior for the ESD generator to a cable setup. The new model can be used for simulation of arbitrary load conditions, for both direct and indirect discharge. The model represents the individual characteristics of an ESD generator without applying complex 3D field simulation. It allows computation of the coupled voltages over linear or nonlinear termination using a circuit simulator.
{"title":"Circuit models for ESD-generator-cable field coupling configurations based on measurement data","authors":"F. Nieden, Stanislav Scheier, Stephan Frei","doi":"10.1109/EMCEUROPE.2012.6396754","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396754","url":null,"abstract":"Accurate and flexible modeling of field coupling from ESD sources to cables or PCB traces (indirect ESD) is important for immunity estimations. Accurate circuit models can be obtained by applying approximations techniques to measurement data in frequency domain. In this paper an accurate ESD generator model is extended to model ESD coupling behavior for the ESD generator to a cable setup. The new model can be used for simulation of arbitrary load conditions, for both direct and indirect discharge. The model represents the individual characteristics of an ESD generator without applying complex 3D field simulation. It allows computation of the coupled voltages over linear or nonlinear termination using a circuit simulator.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115897656","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396730
C. Gazda, H. Rogier, D. Vande Ginste, I. Couckuyt, T. Dhaene
An optimal common-mode suppression filter for a bend discontinuity in a pair of differential lines is characterized simultaneously by a large reduction of conversion noise, a small differential mode reflection coefficient and low overall loss, taking into account technology constraints. To find the geometrical parameters of such optimal design, a novel constrained multi-objective optimization method, relying on intermediate surrogate models of several costs, is proposed. A 3D Pareto-front is generated and further, constrained to impose hardware limitations. The front shows trade-offs between the different cost functions, as such allowing to choose an optimal solution from a large set of available layouts. As is often the case, the filter design occurs in the frequency domain. Additionally, in this contribution the method is also validated by means of a time domain analysis, confirming its accuracy and efficiency.
{"title":"Time domain analysis of a common-mode suppression filter subjected to a multi-objective optimization","authors":"C. Gazda, H. Rogier, D. Vande Ginste, I. Couckuyt, T. Dhaene","doi":"10.1109/EMCEUROPE.2012.6396730","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396730","url":null,"abstract":"An optimal common-mode suppression filter for a bend discontinuity in a pair of differential lines is characterized simultaneously by a large reduction of conversion noise, a small differential mode reflection coefficient and low overall loss, taking into account technology constraints. To find the geometrical parameters of such optimal design, a novel constrained multi-objective optimization method, relying on intermediate surrogate models of several costs, is proposed. A 3D Pareto-front is generated and further, constrained to impose hardware limitations. The front shows trade-offs between the different cost functions, as such allowing to choose an optimal solution from a large set of available layouts. As is often the case, the filter design occurs in the frequency domain. Additionally, in this contribution the method is also validated by means of a time domain analysis, confirming its accuracy and efficiency.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129695551","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396736
Xian-Ke Gao, H. Yik, Boon-Hui Lim, Huapeng Zhao, Binfang Wang, E. Li
This paper presents a system-level modeling method by integrating analytical and numerical methods to analyze conducted and radiated electromagnetic immunity of electronic systems. Through extracting the intrinsic behavioural characteristics from cables, PCBA (board, traces, vias, connectors and components) and enclosure by using the semi-analytical method, one equivalent circuit model is built which is capable of simulating the transient/AC responses and crosstalk under conducted and/or radiated electromagnetic interference. A computer aided modelling system is developed to help industry engineers utilize the proposed methodology for their EMC design.
{"title":"Integrated analytical and numerical modeling for system level conducted/radiated immunity analysis","authors":"Xian-Ke Gao, H. Yik, Boon-Hui Lim, Huapeng Zhao, Binfang Wang, E. Li","doi":"10.1109/EMCEUROPE.2012.6396736","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396736","url":null,"abstract":"This paper presents a system-level modeling method by integrating analytical and numerical methods to analyze conducted and radiated electromagnetic immunity of electronic systems. Through extracting the intrinsic behavioural characteristics from cables, PCBA (board, traces, vias, connectors and components) and enclosure by using the semi-analytical method, one equivalent circuit model is built which is capable of simulating the transient/AC responses and crosstalk under conducted and/or radiated electromagnetic interference. A computer aided modelling system is developed to help industry engineers utilize the proposed methodology for their EMC design.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134462038","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 : 2012-12-31DOI: 10.1109/EMCEUROPE.2012.6396765
D. Cottet, I. Stevanovic, B. Wunsch, D. Daroui, J. Ekman, G. Antonini
This paper presents recent progress in the acceleration of PEEC based electromagnetic simulations and its impact on the design of complex bus bar structures as used in multilevel power converters. The approach presented consists of different dedicated acceleration methods for the different design tasks. The first acceleration technique applied is the so called reluctance matrix method for full 3D field results, reducing memory consumption by orders of magnitude and computing time by a factor 3 to 5. The second acceleration method applied is based on model order reduction techniques for port-to-port impedance extraction, reducing the computation time by about one order of magnitude and allowing wideband macro modeling for system level simulations. The paper focuses on the application of these methods showing the impact on practical bus bar design tasks.
{"title":"EM simulation of planar bus bars in multi-level power converters","authors":"D. Cottet, I. Stevanovic, B. Wunsch, D. Daroui, J. Ekman, G. Antonini","doi":"10.1109/EMCEUROPE.2012.6396765","DOIUrl":"https://doi.org/10.1109/EMCEUROPE.2012.6396765","url":null,"abstract":"This paper presents recent progress in the acceleration of PEEC based electromagnetic simulations and its impact on the design of complex bus bar structures as used in multilevel power converters. The approach presented consists of different dedicated acceleration methods for the different design tasks. The first acceleration technique applied is the so called reluctance matrix method for full 3D field results, reducing memory consumption by orders of magnitude and computing time by a factor 3 to 5. The second acceleration method applied is based on model order reduction techniques for port-to-port impedance extraction, reducing the computation time by about one order of magnitude and allowing wideband macro modeling for system level simulations. The paper focuses on the application of these methods showing the impact on practical bus bar design tasks.","PeriodicalId":377100,"journal":{"name":"International Symposium on Electromagnetic Compatibility - EMC EUROPE","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133460000","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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