Pub Date : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10002958
N. S. Trufanova, S. Artishchev, A. Loschilov, E. R. Ragimov
The paper looks at the use of additive printer technology for the manufacture of elements and devices. Using printer technology, a low-pass filter was made, as well as a bandpass filter. The cutoff frequency of the low-pass filter was 100 MHz. Losses in the low-pass filter in the operating frequency range do not exceed 0.3 dB, attenuation in the suppression band at −15 dB. The cutoff frequency of the bandpass filter is 2 GHz. This results in a filter loss of minus 3.4 dB at 2 GHz.
{"title":"Manufacturing of Hybrid Integrated Circuits Using Additive Printer Technology","authors":"N. S. Trufanova, S. Artishchev, A. Loschilov, E. R. Ragimov","doi":"10.1109/SIBCON56144.2022.10002958","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10002958","url":null,"abstract":"The paper looks at the use of additive printer technology for the manufacture of elements and devices. Using printer technology, a low-pass filter was made, as well as a bandpass filter. The cutoff frequency of the low-pass filter was 100 MHz. Losses in the low-pass filter in the operating frequency range do not exceed 0.3 dB, attenuation in the suppression band at −15 dB. The cutoff frequency of the bandpass filter is 2 GHz. This results in a filter loss of minus 3.4 dB at 2 GHz.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114519494","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10002963
Kuzmin Nikita, Y. Zhechev
This paper considers the influence of the etching time for printed circuit boards on their characteristics on the example of a single microstrip line. A full-scale experiment on fabricating printed circuit boards was carried out using the subtractive method, and their characteristics were measured. Quasi-static and electrodynamic simulations of the structures were performed.
{"title":"Influence of Etching Time on Per-Unit-Length Parameters of Microstrip Lines","authors":"Kuzmin Nikita, Y. Zhechev","doi":"10.1109/SIBCON56144.2022.10002963","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10002963","url":null,"abstract":"This paper considers the influence of the etching time for printed circuit boards on their characteristics on the example of a single microstrip line. A full-scale experiment on fabricating printed circuit boards was carried out using the subtractive method, and their characteristics were measured. Quasi-static and electrodynamic simulations of the structures were performed.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"287 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124577440","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10002970
A. Parshin, Y. Parshin
The efficiency of MIMO communication systems depends on the presence or absence of information about the channel matrix on the receiving side and the transmitting side as well. To obtain this information, time-sequential measurement of the matrix of channel coefficients by multiplexing SIMO channels is widely used. The effect of the phase noise of the transmitter and receiver local oscillators on the measurement accuracy of the channel matrix is analyzed for different ratios of the line of sight power and the diffusion component. The fractal Brownian motion model is used to describe the long-term correlation of phase noise. The effect of channel matrix errors on the capacity of a MIMO system is considered. The analysis was carried out for the characteristics of the phase noise of the MG3690B generator and the bandwidth of the NB-IoT communication system. The results obtained make it possible to substantiate the requirements for the level of phase noise, as well as for the measurement time of the channel matrix to obtain the maximum capacity.
{"title":"Outage Probability of MIMO Communication System under the Influence of Correlated Phase Noise","authors":"A. Parshin, Y. Parshin","doi":"10.1109/SIBCON56144.2022.10002970","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10002970","url":null,"abstract":"The efficiency of MIMO communication systems depends on the presence or absence of information about the channel matrix on the receiving side and the transmitting side as well. To obtain this information, time-sequential measurement of the matrix of channel coefficients by multiplexing SIMO channels is widely used. The effect of the phase noise of the transmitter and receiver local oscillators on the measurement accuracy of the channel matrix is analyzed for different ratios of the line of sight power and the diffusion component. The fractal Brownian motion model is used to describe the long-term correlation of phase noise. The effect of channel matrix errors on the capacity of a MIMO system is considered. The analysis was carried out for the characteristics of the phase noise of the MG3690B generator and the bandwidth of the NB-IoT communication system. The results obtained make it possible to substantiate the requirements for the level of phase noise, as well as for the measurement time of the channel matrix to obtain the maximum capacity.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115786982","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10003025
D. Ponamarev
The article discusses methods for generating twisted radio waves, as well as the possibility of using the properties of twisted radio waves in a polarizing radar. The problematic situation associated with the lack of scientific groundwork on this topic was described. As a result, the author presented the scientific and applied relevance of this topic as a fundamentally new direction in radars.
{"title":"Application of Twisted Radio Waves in a Polarization Radiolocation","authors":"D. Ponamarev","doi":"10.1109/SIBCON56144.2022.10003025","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10003025","url":null,"abstract":"The article discusses methods for generating twisted radio waves, as well as the possibility of using the properties of twisted radio waves in a polarizing radar. The problematic situation associated with the lack of scientific groundwork on this topic was described. As a result, the author presented the scientific and applied relevance of this topic as a fundamentally new direction in radars.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127577509","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 : 2022-11-17DOI: 10.1109/sibcon56144.2022.10003027
{"title":"SIBCON 2022 Cover Page","authors":"","doi":"10.1109/sibcon56144.2022.10003027","DOIUrl":"https://doi.org/10.1109/sibcon56144.2022.10003027","url":null,"abstract":"","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"339 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116473550","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10003012
V. M. Artyushenko, V. I. Volovach
An approach for determining the correlation functions of the noise modulation function under the influence of modulating (or more often multiplicative) noise is described. Both stationary and slow noise is considered as influencing multiplicative noise. Correlation functions of noise modulation and fluctuations of the latter can be found by the four-dimensional characteristic function of phase and amplitude distortions. We have derived expressions for the abovementioned correlation functions affected by static multiplicative noise for the normal law of variation of amplitude and phase distortions in the case of their uncorrelation and cross-correlation. The correlation functions of noise modulation and noise modulation function fluctuations under the influence of slow modulating noise were determined for the case when the phase and distortion amplitude variations are independent. The expressions of the correlation functions of noise modulation and its fluctuations for correlated and normal distribution of phase and amplitude distortions under the influence of slow modulating noise are obtained.
{"title":"Correlation Functions of the Noise Modulation Function under the Influence of Stationary and Slow Multiplicative Noise","authors":"V. M. Artyushenko, V. I. Volovach","doi":"10.1109/SIBCON56144.2022.10003012","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10003012","url":null,"abstract":"An approach for determining the correlation functions of the noise modulation function under the influence of modulating (or more often multiplicative) noise is described. Both stationary and slow noise is considered as influencing multiplicative noise. Correlation functions of noise modulation and fluctuations of the latter can be found by the four-dimensional characteristic function of phase and amplitude distortions. We have derived expressions for the abovementioned correlation functions affected by static multiplicative noise for the normal law of variation of amplitude and phase distortions in the case of their uncorrelation and cross-correlation. The correlation functions of noise modulation and noise modulation function fluctuations under the influence of slow modulating noise were determined for the case when the phase and distortion amplitude variations are independent. The expressions of the correlation functions of noise modulation and its fluctuations for correlated and normal distribution of phase and amplitude distortions under the influence of slow modulating noise are obtained.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128911522","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10002968
Kudryavtsev Denis, Zorkaltsev Aleksandr, Soldatov Aleksei
Worldwide trends in the development of inter-vehicle communications have led to the emergence of projects such as See-Through [1], [2] and Samsung The Safety Truck [3]. These projects are aimed at increasing the safety of drivers when overtaking-the most dangerous maneuver on the road. Upon a detailed review of the projects, it became clear that there are other ways to safely overtake. For example, if a camera and equipment for wireless data transfer are installed on the overtaking car (truck, bus), and the smartphone of the driver of the overtaking car acts as a receiver. In this case, Wi-Fi may be suitable as wireless data technology. This technology, in theory, can provide the video stream to a distance necessary to assess the situation and start overtaking, and Wi-Fi is supported by the vast majority of modern smartphones. In this regard, it was necessary to assess the possibility of transmitting a video stream from one car to another during their movement and to choose the optimal Wi-Fi settings.
在全球范围内，车辆间通信的发展趋势导致了诸如See-Through[1]、[2]和Samsung the Safety Truck[3]等项目的出现。这些项目旨在提高司机超车时的安全性，超车是道路上最危险的动作。在对这些项目进行详细审查后，很明显还有其他安全超车的方法。例如，在超车(卡车、公交车)上安装摄像头和无线数据传输设备，超车司机的智能手机充当接收器。在这种情况下，Wi-Fi可能适合作为无线数据技术。从理论上讲，这项技术可以提供视频流到必要的距离，以评估情况并开始超车，而且绝大多数现代智能手机都支持Wi-Fi。在这方面，有必要评估在行驶过程中从一辆车向另一辆车传输视频流的可能性，并选择最佳的Wi-Fi设置。
{"title":"Effects of Critical Parameters Wireless Data Network on Video Stream Stability in v2v/v2p Communications","authors":"Kudryavtsev Denis, Zorkaltsev Aleksandr, Soldatov Aleksei","doi":"10.1109/SIBCON56144.2022.10002968","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10002968","url":null,"abstract":"Worldwide trends in the development of inter-vehicle communications have led to the emergence of projects such as See-Through [1], [2] and Samsung The Safety Truck [3]. These projects are aimed at increasing the safety of drivers when overtaking-the most dangerous maneuver on the road. Upon a detailed review of the projects, it became clear that there are other ways to safely overtake. For example, if a camera and equipment for wireless data transfer are installed on the overtaking car (truck, bus), and the smartphone of the driver of the overtaking car acts as a receiver. In this case, Wi-Fi may be suitable as wireless data technology. This technology, in theory, can provide the video stream to a distance necessary to assess the situation and start overtaking, and Wi-Fi is supported by the vast majority of modern smartphones. In this regard, it was necessary to assess the possibility of transmitting a video stream from one car to another during their movement and to choose the optimal Wi-Fi settings.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128870419","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10003004
V. Sergey, Y. Zhechev
This paper investigates a four-layer reflection symmetric structure in common and differential modes. By using electrodynamic approach, the authors simulated S parameters and represented them into time responses in the Advanced Design System 2022. The study shows that the ultra-wideband pulses are decomposed into the sequence of pulses with lower amplitudes. To evaluate these pulses, the authors used N-norms. It was found that the MF under investigation allows significant attenuation of the ultra-wideband interference in both modes. Thus, the N1 value for the differential mode decreased by 4.51 times, N2 by 5.82 times, N3 by 1.34 times, N4 by 1.34 times, and N5 by 2.64 times. For the common mode, N1 decreased by 2.97 times, N2 by 4.64 times, and N5 by 1.7 times. The signal integrity analysis in differential mode demonstrated that structure under study may be used for protecting signal circuits against ultra-wideband interference.
{"title":"Four-Layer Reflection-Symmetric Structure in Common and Differential Modes","authors":"V. Sergey, Y. Zhechev","doi":"10.1109/SIBCON56144.2022.10003004","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10003004","url":null,"abstract":"This paper investigates a four-layer reflection symmetric structure in common and differential modes. By using electrodynamic approach, the authors simulated S parameters and represented them into time responses in the Advanced Design System 2022. The study shows that the ultra-wideband pulses are decomposed into the sequence of pulses with lower amplitudes. To evaluate these pulses, the authors used N-norms. It was found that the MF under investigation allows significant attenuation of the ultra-wideband interference in both modes. Thus, the N1 value for the differential mode decreased by 4.51 times, N2 by 5.82 times, N3 by 1.34 times, N4 by 1.34 times, and N5 by 2.64 times. For the common mode, N1 decreased by 2.97 times, N2 by 4.64 times, and N5 by 1.7 times. The signal integrity analysis in differential mode demonstrated that structure under study may be used for protecting signal circuits against ultra-wideband interference.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131947296","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10002954
T. T. Thanh, G. Malyutin, A. Loschilov
The frequency characteristics of coupled strip lines (CSL) sections, with RLC band-stop filters (BSF) included in the diagonal arms, have been considered. The variable parameter of CSL was the phase velocities ratio of inphase and antiphase excitation modes of waves propagating in the lines. The scattering matrix coefficients and group delay time have been calculated for inphase and antiphase waves velocity ratios of 0.8, 1.54, 1. 02.It has been shown that the sections have the property of band-pass filters (BPF) with the following features. First, at an average frequency of 1 GHz of the passband at out-of-band frequencies up to 8 GHz there are no stray band-passes with relatively low return loss at the specified phase velocity ratios. Second, there is an optimal value of the phase velocity ratio close to 1.0, at which the insertion loss and return loss are minimal. Third, the considered links of CSL give a maximum group delay time with an increase up to 3 ns at the center frequency of the passband in contrast to the classical links of bandpass filters on coupled lines. It has been shown experimentally that the possibility of using sections loaded with band-stop RLC-filters as links of band-pass filters with minimal losses of less than 2 dB and with the properties of absorption-type filters at out-of-band frequencies in the absence of stray passbands.
{"title":"Features of Frequency Response Transformations of RLC Circuits into Opposite Response when Using them as a Load of Coupled Strip Lines with Unequal Waves Phase Velocities","authors":"T. T. Thanh, G. Malyutin, A. Loschilov","doi":"10.1109/SIBCON56144.2022.10002954","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10002954","url":null,"abstract":"The frequency characteristics of coupled strip lines (CSL) sections, with RLC band-stop filters (BSF) included in the diagonal arms, have been considered. The variable parameter of CSL was the phase velocities ratio of inphase and antiphase excitation modes of waves propagating in the lines. The scattering matrix coefficients and group delay time have been calculated for inphase and antiphase waves velocity ratios of 0.8, 1.54, 1. 02.It has been shown that the sections have the property of band-pass filters (BPF) with the following features. First, at an average frequency of 1 GHz of the passband at out-of-band frequencies up to 8 GHz there are no stray band-passes with relatively low return loss at the specified phase velocity ratios. Second, there is an optimal value of the phase velocity ratio close to 1.0, at which the insertion loss and return loss are minimal. Third, the considered links of CSL give a maximum group delay time with an increase up to 3 ns at the center frequency of the passband in contrast to the classical links of bandpass filters on coupled lines. It has been shown experimentally that the possibility of using sections loaded with band-stop RLC-filters as links of band-pass filters with minimal losses of less than 2 dB and with the properties of absorption-type filters at out-of-band frequencies in the absence of stray passbands.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132657867","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 : 2022-11-17DOI: 10.1109/SIBCON56144.2022.10002991
V. Chumakov, A. Bugakova, A. Titov
The original architecture of operational amplifiers (OpAmps) implemented on complementary JFETs or depletion-mode complementary MOS is considered. The feature of the proposed OpAmps is differential input stage and folded-cascode special designs, which have a high symmetry of the FETs static regime from terms of gate-to-drain voltages. Computer-based simulations of the OpAmp in the LTspice-XVII was conducted between -197 and 27 degrees Celsius. The proposed circuit solutions reduce the systematic constituent of the offset-voltage (up to 10 $mu mathrm{V}$) and increase voltage gain (up to 87 dB) of the open-loop OpAmp. The explored OpAmps are recommended by the authors of the article for analogue, including low-noise, and analogue-to-digital devices, for example, active filters, comparators, actuators, and others, which are used in systems of communication and management, such as at cryogenic temperatures, and/or under radiation conditions.
{"title":"Low-Temperature JFET OpAmp Based On a Folded-Cascode with High Static Regime Symmetry of Transistors That Determine the Systematic Constituent of the Offset-Voltage","authors":"V. Chumakov, A. Bugakova, A. Titov","doi":"10.1109/SIBCON56144.2022.10002991","DOIUrl":"https://doi.org/10.1109/SIBCON56144.2022.10002991","url":null,"abstract":"The original architecture of operational amplifiers (OpAmps) implemented on complementary JFETs or depletion-mode complementary MOS is considered. The feature of the proposed OpAmps is differential input stage and folded-cascode special designs, which have a high symmetry of the FETs static regime from terms of gate-to-drain voltages. Computer-based simulations of the OpAmp in the LTspice-XVII was conducted between -197 and 27 degrees Celsius. The proposed circuit solutions reduce the systematic constituent of the offset-voltage (up to 10 $mu mathrm{V}$) and increase voltage gain (up to 87 dB) of the open-loop OpAmp. The explored OpAmps are recommended by the authors of the article for analogue, including low-noise, and analogue-to-digital devices, for example, active filters, comparators, actuators, and others, which are used in systems of communication and management, such as at cryogenic temperatures, and/or under radiation conditions.","PeriodicalId":265523,"journal":{"name":"2022 International Siberian Conference on Control and Communications (SIBCON)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128139405","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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