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2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)最新文献

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Role of the external drivers in the occurrence of low-latitude ionospheric scintillation revealed by multi-scale analysis 多尺度分析揭示了低纬电离层闪烁发生的外部驱动因素
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738254
L. Spogli, M. Piersanti, C. Cesaroni, M. Materassi, A. Cicone, L. Alfonsi, V. Romano, R. Ezquer
{"title":"Role of the external drivers in the occurrence of low-latitude ionospheric scintillation revealed by multi-scale analysis","authors":"L. Spogli, M. Piersanti, C. Cesaroni, M. Materassi, A. Cicone, L. Alfonsi, V. Romano, R. Ezquer","doi":"10.23919/URSIAP-RASC.2019.8738254","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738254","url":null,"abstract":"In the low latitude ionosphere, the formation of Equatorial Plasma Bubbles presents a regular behavior under quiet conditions of the geospace. The ionospheric irregularities embedded in the plasma bubbles may lead to amplitude scintillation of Global Navigation Satellite Systems signals. Solar events disturb the regular behavior of the magnetosphere-ionosphere system, leading to an intensification or a suppression of such ionospheric irregularities producing scintillations. During the same storm, inhibition and intensification of the ionospheric scintillations can both occur, depending on the local time of the storm arrival and on the storm features. Electric fields penetrating from the auroral latitudes and disturbing the ionospheric electrodynamics are commonly highlighted as the principal responsible for the inhibited/enhanced scintillations. Beside this mechanism, the disturbance dynamo is the concurrent key-physical phenomenon, being due to variations of the thermospheric winds induced by heating convecting from high towards equatorial latitudes and disturbing the electrodynamics of the Equatorial Electrojet [1]. In the present work, we analyze the scintillation over San Miguel de Tucumán (Argentina), located under the southern crest of the Equatorial Ionospheric Anomaly, focusing on the multi-scale variability and on the causal relationship between forcing factors from the geospace and the ionospheric response.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128853684","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}
引用次数: 16
Calculation of the Lightning Induced Response on Overhead Transmission Lines based on the Electric Field Representation Methods 基于电场表示法的架空输电线路雷击感应响应计算
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738640
Jun Guo, Yan-zhao Xie
{"title":"Calculation of the Lightning Induced Response on Overhead Transmission Lines based on the Electric Field Representation Methods","authors":"Jun Guo, Yan-zhao Xie","doi":"10.23919/URSIAP-RASC.2019.8738640","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738640","url":null,"abstract":"The transient electromagnetic field produced by an indirect lightning can induce to overhead power lines, which may cause serious effects to the power system. When calculating the lightning induced voltages on the overhead lines with the conventional numerical method, to pursue a sufficiently accurate results, the lightning electric field at a large number of observation points along the lines should be calculated. However, since the numerical integration are commonly involved when calculating the lightning electric field, the significant CPU cost is normally required for the whole computational procedure. In order to enhance the computational efficiency, two approaches which based on the electric field representation technique were proposed. In these two methods, the lightning electric fields at several observation points along the line are calculated by using the conventional numerical method first, then the electric field along the entire line can be represented with the continuous functions by using two different fitting methods, which are matrix pencil method (MPM) and the least squares-nonlinear least squares (LS-NLS) method. As a result, the necessary number of observation points where the lightning electric field should be calculated by using the conventional numerical methods is significantly decreased. The proposed methods were validated and compared by some numerical examples.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127247505","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}
引用次数: 0
Spectrum monitor system at QTT site QTT站点的频谱监测系统
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738395
Qi Liu, Yue Wang, Ye Liu, Na Wang, Feng Liu, Hao Yan, Yang Wang
{"title":"Spectrum monitor system at QTT site","authors":"Qi Liu, Yue Wang, Ye Liu, Na Wang, Feng Liu, Hao Yan, Yang Wang","doi":"10.23919/URSIAP-RASC.2019.8738395","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738395","url":null,"abstract":"QTT is a steerable 110 m radio aperture telescope that will be built in Xinjiang province of china, with a frequency range from 150 MHz to 115 GHz. Site RFI levels is clearly an important issue for such a sensitive instrument. Therefore, we have developed an automated highly sensitive and reliable spectrum monitor system for RFI detected and signal characteristic analyzed, a quasi-real-time measured method was employed for long-term spectrum monitoring, and we used the HDF5 data format for RFI data storage and management. This system is working well at QTT site for a long time, we proposed some considerations for how to process and analyze so much RFI data during spectrum monitoring, and the data processing procedures should be updated in the future work to improve RFI analyzed efficiency.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115618699","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}
引用次数: 2
The preliminary evaluation of the new fountain clock NIM6 新型喷泉钟NIM6的初步评价
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738417
F. Fang, Weiliang Chen, Kun Liu, Nianfeng Liu, Lei Han, Tian-chu Li
{"title":"The preliminary evaluation of the new fountain clock NIM6","authors":"F. Fang, Weiliang Chen, Kun Liu, Nianfeng Liu, Lei Han, Tian-chu Li","doi":"10.23919/URSIAP-RASC.2019.8738417","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738417","url":null,"abstract":"In this paper, we introduce the design of our new fountain clock NIM6. Besides some improvements on the vacuum system, Ramsey cavity to reduce the Type B uncertainty, NIM6 collects atoms from a MOT loading optical molasses to get a better signal to noise ratio. The atom density will be more uniform compared to a 2D MOT loading optical molasses, and the diameter of the cloud can be adjusted by the intensity and detuning of lights during the post cooling after MOT to keep the collisional shift low. Cs atoms are collected in the lower MOT chamber for 0.5 second, and then the MOT magnetic field is turned down. Atoms are accelerated for 1 ms in a moving molasses, and further cooled for another 1.5 ms by adiabatically reducing the cooling beam intensities and red offsetting the frequencies.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115748827","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}
引用次数: 3
Excitation Amplitude/Phase Sensitivity in Circularly Polarized Hexagonal S-Band Antenna 圆极化六方s波段天线的激励幅相灵敏度
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738710
A. Joshi, R. Singhal
{"title":"Excitation Amplitude/Phase Sensitivity in Circularly Polarized Hexagonal S-Band Antenna","authors":"A. Joshi, R. Singhal","doi":"10.23919/URSIAP-RASC.2019.8738710","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738710","url":null,"abstract":"A probe-fed circularly polarized hexagonal patch antenna with dual feed configuration is designed and presented for analyzing amplitude and phase sensitivity. The hexagonal patch antenna is excited with a fundamental frequency of 2.45 GHz through two feeds separated by an angle of 90° and 90° phase shift. The probe feed positions are optimized along the X- and the Y-direction of the patch antenna plane with and without simultaneous excitation. The sensitivity of circular polarization purity towards change in amplitude and phase of excitation signal is studied for a dual port hexagonal S-Band antenna.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"216 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124267787","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}
引用次数: 0
Improvement of the Execution Performance for 3-D Impedance Method by Clarification of its Matrix Form Representation 澄清三维阻抗法的矩阵形式表示以提高其执行性能
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738764
Yukihisa Suzuki, M. Taki
{"title":"Improvement of the Execution Performance for 3-D Impedance Method by Clarification of its Matrix Form Representation","authors":"Yukihisa Suzuki, M. Taki","doi":"10.23919/URSIAP-RASC.2019.8738764","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738764","url":null,"abstract":"Recently, numerous research institution and companies conduct the investigation and the development of wireless power transfer (WPT) systems. Especially, WPT systems using intermediate frequency band, e.g. around 85kHz, magnetic field have gained attention for the charging method of electric vehicle. Therefore, there is growing concern about health effects induced by magnetic fields (MFs) of the intermediate frequency band. The 3-D impedance method (IM) is one of the techniques to evaluate the induced electric field and current density within the biological body caused by MFs exposure in the intermediate frequency band for which quasi-static approximation is applied.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124384185","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}
引用次数: 0
Generation of Pulsed Fiber Laser: ns to fs domain 脉冲光纤激光器的产生:ns到fs域
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738439
M. Pal, S. D. Chowdhury, Nishant Kumar Shehar, R. Sen
{"title":"Generation of Pulsed Fiber Laser: ns to fs domain","authors":"M. Pal, S. D. Chowdhury, Nishant Kumar Shehar, R. Sen","doi":"10.23919/URSIAP-RASC.2019.8738439","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738439","url":null,"abstract":"Recently fiber lasers have become an indispensable tool in scientific endeavors as well as in multifarious industrial applications. While high power continues wave fiber lasers delivering hundreds of watts to killo-watts of average power are being used in manufacturing and strategic sectors for cutting, welding, additive manufacturing and directed energy applications, pulsed fiber lasers operating in the kHz repetition rate and nano-second pulse duration with pulse energies from micro-joule to mille-joule are being used for marking and engraving applications. These pulses are usually obtained from a Q-switched master oscillator power amplifier (MOPA) fiber laser or by amplifying a gain-switched laser diode to suitable pulse energy and power. Apart from this class of pulsed fiber lasers, mode-locked fiber lasers which now a days can deliver a very large variety of pulse duration ranging from femto-seconds to micro-seconds, are used for more precise and novel applications such as marking/ engraving on reflecting/ transmitting materials, nonlinear wavelength conversion, label free nonlinear microscopy, novel pump sources and also for study of various pulse dynamics [1, 2].","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124564004","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}
引用次数: 0
Proposed VLBI Study on Pulsars Discovered by FAST FAST发现脉冲星的VLBI研究
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738166
Ru-Rong Chen, Haiyan Zhang, Z. Pan, Y. Yue, Jiguang Lu, Bo Zhang
{"title":"Proposed VLBI Study on Pulsars Discovered by FAST","authors":"Ru-Rong Chen, Haiyan Zhang, Z. Pan, Y. Yue, Jiguang Lu, Bo Zhang","doi":"10.23919/URSIAP-RASC.2019.8738166","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738166","url":null,"abstract":"The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the largest single dish radio telescope in the word, which has discovered more than 40 new pulsars. EVN observations have been proposed to measure the astrometric parameters of three FAST pulsars, which are model independent and useful for pulsar timing and luminosity estimation. The FAST VLBI system has also been developed, which is being tested now and would significantly improve the sensitivity of the existing VLBI networks in the future.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114304412","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}
引用次数: 0
An Improved Random Forest Algorithm for classification in an imbalanced dataset. 一种用于不平衡数据集分类的改进随机森林算法。
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738232
C. Jose, G. Gopakumar
{"title":"An Improved Random Forest Algorithm for classification in an imbalanced dataset.","authors":"C. Jose, G. Gopakumar","doi":"10.23919/URSIAP-RASC.2019.8738232","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738232","url":null,"abstract":"Nowadays machine learning algorithms are being used extensively in industrial applications. Many a times these algorithms are modified and fine tuned so as to improve the current products and get better results. In this paper, we analyse an industrial problem that was put forward in the ‘IDA 2016 challenge’ and propose an improved solution over the best solution identified as part of the challenge.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115016552","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}
引用次数: 7
Isolation Enhancement in Two Port Mimo System Using Parallel Coupled Lines 利用并行耦合线增强双端口Mimo系统的隔离
2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) Pub Date : 2019-03-01 DOI: 10.23919/URSIAP-RASC.2019.8738680
R. Mark, N. Rajak, Soma Das
{"title":"Isolation Enhancement in Two Port Mimo System Using Parallel Coupled Lines","authors":"R. Mark, N. Rajak, Soma Das","doi":"10.23919/URSIAP-RASC.2019.8738680","DOIUrl":"https://doi.org/10.23919/URSIAP-RASC.2019.8738680","url":null,"abstract":"In this paper, we implemented a parallel line coupled resonator for isolation enhancement in multiple-input-multiple-output (MIMO) antenna system for WLAN application. The edge-to-edge spacing between antenna elements is 3. $8mm (0.072lambda_{o}, lambda_{o}$ is the free space wavelength at 5.7GHz).The decoupling structure consists of parallel coupled resonator structure acting as band reject filter that helps to nulliry the near coupled field between antenna system. The parametric study is done to optimize the length of coupled resonator so as to obtain high isolation between antenna elements at resonating frequency. The simulated efficiency remains above 88% along with envelope correlation coefficient (ECC) value lower than 0.03, making the design practicable for MIMO WLAN application.","PeriodicalId":344386,"journal":{"name":"2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116890275","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}
引用次数: 1
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