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2020 International Conference engineering and Telecommunication, En and T 2020

作者： Nguyen, Duy Phuong Kozyrev, Dmitry Vladimirovich School of Radio Engineering and Computer Technology Moscow Institute of Physics and Technology National Research University Dolgoprudny Moscow Region Russia Peoples Friendship University of Russia Rudn University 6 Miklukho-Maklaya St Moscow117198 Russia V. A. Trapeznikov Institute of Control Sciences of Russian Academy of Sciences Moscow Russia

ISBN: (纸本)9781728188294

One of the promising directions in the framework of the concept of creating the next-generation 5G/IMT-2020 networks is the development of broadband wireless networks based on autonomous unmanned aerial vehicles (UAVs). In addition to the interest in autonomous UAV-based high-altitude platforms (HAPs), leading researchers are currently engaged in the design and implementation of tethered unmanned HAPs, which are intended to be long-term operating and are widely used in civilian and military areas. Their possibility of long-term operation, which is one of the main advantages over autonomous UAVs, puts forward new reliability requirements. In this paper we study an analytical reliability model of the multi rotor flight module of the tethered HAP as a homogeneous hot-standby system consisting of $n$ elements operating in a random environment. A general Markov reliability model of the considered system operating in a random environment is proposed, which accounts for the increase in the functional load and the location of the failed components. © 2020 IEEE.

关键词： Reliability analysis

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Feed array with overlapping clusters and flat-topped radiation pattern for multi-beam satellite communication antennas

Feed array with overlapping clusters and flat-topped radiati...

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engineering and Telecommunication (En&T), International Conference

作者： I. L. Vilenko A.V. Shishlov Y.V. Krivosheev M.S. Uhm S.H. Yun JSC Radiofizika Moscow Russia School of Radio Engineering and Computer Technology Moscow Institute of Physics and Technology Dolgoprudny Russia School of Engineering Moscow Aviation Institute Moscow Russia Radio & Satellite Research Division Electronics and Telecommunications Research Institute Daejeon Republic of Korea

ISBN: (纸本)9781728188300

A new feed array with overlapping clusters for multi-beam satellite communication antennas is presented. The array consists of circular waveguides with diameter of 1.1 wavelength. Neighbor elements are excited via the slots and thus overlapping clusters are formed. Excitation of the clusters is optimized to obtain flat-topped radiation pattern and high aperture efficiency. The proposed array can be used as a feed for multi-beam antennas.

关键词： Circular waveguides Satellite antennas Apertures Antenna feeds Satellite communication Antenna arrays Antenna radiation patterns

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Bright bursts with sub-millisecond structures of FRB 20230607A in a highly magnetized environment

arXiv

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arXiv 2025年

作者： Zhou, DeJiang Han, J.L. Zhang, Bing Zhu, WeiWei Wang, Wei-Yang Yang, Yuan-Pei Qu, Yuanhong Zhang, Yong-Kun Yan, Yi Jing, Wei-Cong Cao, Shuo Xie, Jintao Yang, Xuan Tian, Shiyan Li, Ye Li, Dongzi Niu, Jia-Rui Wu, Zi-Wei Wu, Qin Feng, Yi Wang, Fayin Wang, Pei National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences Beijing100101 China Nevada Center for Astrophysics University of Nevada Las VegasNV89154-4002 United States Department of Physics and Astronomy University of Nevada Las VegasNV89154-4002 United States Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Department of Astronomy School of Physics Peking University Beijing100871 China South-Western Institute for Astronomy Research Yunnan University Yunnan Kunming650504 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Research Center for Astronomical Computing Zhejiang Laboratory Hangzhou311100 China School of Computer Science and Engineering Sichuan University of Science and Engineering Yibin644000 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210008 China School of Astronomy and Space Sciences University of Science and Technology of China Hefei230026 China Department of Astronomy School of Physics Huazhong University of Science and Technology Wuhan430074 China Cahill Center for Astronomy and Astrophysics California Institute of Technology PasadenaCA United States School of Astronomy and Space Science Nanjing University Nanjing210093 China Institute for Astronomy School of Physics Zhejiang University Hangzhou310027 China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Nanjing210093 China

We report the observations of a repeating FRB 20230607A for 15.6 hours spanning 16 months using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with the detection of 565 bursts. We present three bright bursts with detailed temporal/spectral structures. We also report that one burst carries a narrow component with a width of only 0.3 ms, which is surrounded by broader components. This suggests that repeaters can make both narrow and broad components in one burst. With the narrow spike, we precisely measure the dispersion measure (DM) of 362.85±0.15 pc cm−3 and the Faraday rotation measures (RMs) of and −12249.0 ± 1.5 rad m−2. We also analyze the statistical distribution of the burst parameters, including waiting times, temporal widths, central frequencies and frequency widths, fluences and energies, all showing typical distributions of known active repeaters. In particular, most bursts show narrow spectra with ∆ν/ν0 = 0.125 ± 0.001. This fact, together with the narrow 0.3 ms spike, strongly suggests a magnetospheric origin of the FRB emission. Based on a predicted correlation between RM and the luminosity of a persistent radio source (PRS) by Yang et al., we predict that PRS should have a specific luminosity of the order of 1029 erg s−1 Hz−1 and encourage a search for such a PRS. © 2025, CC BY-NC-ND.

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Robust Deep Learning-Based Automated Liver Contouring Using a Small Sample of radiotherapy Planning Computed Tomography Images

SSRN

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SSRN 2023年

作者： Arjmandi, Najmeh Momennezhad, Mehdi Arastouei, Soudeh Mosleh Shirazi, Mohammad Amin Hosseini, Sare Albawi, Ali Pishevar, Zohreh Naseri, Shahrokh Department of Medical Physics School of Medicine Mashhad University of Medical Sciences Mashhad Iran Medical Physics Research Center School of Medicine Mashhad University of Medical Sciences Mashhad Iran Department of Radiation Oncology Mashhad University of Medical Sciences Mashhad Iran Ionizing and Non-Ionizing Radiation Protection Research Center School of Paramedical Sciences Shiraz University of Medical Sciences Shiraz Iran Physics Unit Department of Radio-Oncology Shiraz University of Medical Sciences Shiraz Iran Cancer Research Center Mashhad University of Medical Sciences Mashhad Iran Radiology Techniques Department College of Medical Technology The Islamic University Najaf Iraq Department of Computer Engineering Ferdowsi University of Mashhad Mashhad Iran

Background: Manual delineation of liver boundaries on CT images can be prone to errors due to the low intensity contrast between the liver and the surrounding tissues. Therefore, employing an automated technique to perform accurate contouring can be beneficial. To date, state-of-the-art deep learning methods have shown promising results when applied to large sample ***: No study has yet investigated the minimum amount of data required for deep learning-based liver contouring. Therefore, this study aimed to investigate the feasibility of automated liver contouring using limited ***: radiotherapy planning CT images were subjected to various preprocessing methods, such as denoising and windowing. Segmentation was conducted using the modified Attention U-Net and Residual U-Net networks. Two unseen external datasets with different distributions from the training set were also used to examine the generalizability of the proposed ***: The average DSCs for the modified Residual U-Net and Attention U-Net networks were 97.62% and 96.48%, respectively on the test set. The average AHDs for the modified Residual U-Net and Attention U-Net networks were 0.57 mm and 0.71 mm, respectively. Also, the modified Residual U-Net and Attention U-Net networks were tested on two unseen external datasets, achieving DSCs of 95.35% and 95.82% for data from another center and 95.16% and 94.93% for the AbdomenCT-1K dataset, ***: Multiple image preprocessing and modified networks succeeded in contouring the liver on two unseen external datasets, indicating that the proposed method is generalizable and a promising tool for automatic liver contouring in radiotherapy treatment planning. © 2023, The Authors. All rights reserved.

关键词： Deep learning

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An ANTLR-based flattening framework for AltaRica 3.0 model

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International Journal of Performability engineering 2019年第9期15卷 2462-2475页

作者： Hu, Jun Chen, Shuo Chen, Defeng Kang, Jiexiang Wang, Hui College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing211106 China Department of Software China National Aeronautic Radio Electronics Research Institute Shanghai200233 China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing210007 China School of Mechanical Engineering Hefei University of Technology Hefei230601 China

AltaRica is a modeling language that is capable of hierarchical modelling and fault behavior description for industrial safety-critical system design. AltaRica 3.0 is the latest version, and its semantics are based on a formal GTS (Guarded Transition Systems) model. One of the key steps in the process of safety analysis toward AltaRica 3.0 models is that how to flatten a hierarchical AltaRica 3.0 model into a semantically equivalent GTS semantic model. This paper proposes an AltaRica 3.0 model flattening algorithm framework based on ANTLR (Another Tool for Language Recognition). Firstly, considering the different structural features of Block and Class, the AltaRica 3.0 model is sliced carefully in order to obtain the corresponding AST (Abstract Syntax Tree). Secondly, a set of recursive transformation algorithms are designed to extract and transform the AltaRica model elements, which are stored in the AST nodes based on the traversal technique of the AST. Then, a semantically equivalent flattened GTS model can be obtained. Lastly, several case studies show that the algorithms designed in this paper can effectively implement the flattening process of AltaRica 3.0 models. © 2019 Totem Publisher, Inc. All rights reserved.

关键词： Modeling languages

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Analysis of Correlation between Cellular, TV and radio technology to Human Development in Indonesia

Analysis of Correlation between Cellular, TV and Radio techn...

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International Conference on ICT For Smart Society (ICISS)

作者： Zulhaidir Hamid DoHoon Lee Loka Monitor Spektrum Frekuensi Radio Gorontalo Ministry of Communication and Information Technology Indonesia Gorontalo Indonesia School of Computer Science and Engineering Pusan National University Busan South Korea

ISBN: (数字)9781665404228

ISBN: (纸本)9781665404235

The human development was represented with the human development index and the availability of telecommunication service extracted from spectrum frequency monitoring all around Indonesia. In this paper, we find out the correlation between the availability of radio spectrum-related ICTs telecommunication service in the form of mobile cellular, TV broadcast, and radio broadcast with human development by using city-regency level data. We knew that telecommunication service is statistically significant and positively correlated to human development. In particular, mobile cellular service has a higher positive correlation with human development comparing to TV broadcast service, while radio broadcast service does not correlate with human development. We also suggest that policies should give more priorities to the mobile cellular technology for using spectrum frequency as this technology has the highest correlation with human development in Indonesia.

关键词： TV Correlation Broadcasting Urban areas Sociology Monitoring Mathematical model

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New Approach to Improving the Quality for Images Processed with Fractal Compression

New Approach to Improving the Quality for Images Processed w...

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Digital Signal Processing and its Applications (DSPA), International Conference on

作者： Alexander V. Dvorkovich Nikolay B. Novinsky Do Ngoc Diep Multimedia Systems and Technology Lab Moscow Institute of Physics and Technology National Research University Moscow Russian Federation Phystech-School of Radio Engineering and Computer Science Moscow Institute of Physics and Technology National Research University Moscow Russian Federation

ISBN: (数字)9781728175287

ISBN: (纸本)9781728175294

A new method for improvement of images compressed using fractal compression method is under investigation. The experiments had show that the method is principally functional. The improvement of restored images (in terms of PSNR) is relatively small but the method is computationally simple. The effect of its usage is waiting to be greater for large images and complex images.

关键词： Bridges Image coding Fractals Image restoration Standards Physics Distortion

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Reliability Analysis of a Multirotor Flight Module of a High-altitude Telecommunications Platform Operating in a Random Environment

Reliability Analysis of a Multirotor Flight Module of a High...

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engineering and Telecommunication (En&T), International Conference

作者： Duy Phuong Nguyen Dmitry Vladimirovich Kozyrev School of Radio Engineering and Computer Technology Moscow Institute of Physics and Technology (National Research University) Dolgoprudny Moscow Region Russian Federation V. A. Trapeznikov Institute of Control Sciences of Russian Academy of Sciences Moscow Russian Federation

ISBN: (纸本)9781728188300

One of the promising directions in the framework of the concept of creating the next-generation 5G/IMT-2020 networks is the development of broadband wireless networks based on autonomous unmanned aerial vehicles (UAVs). In addition to the interest in autonomous UAV-based high-altitude platforms (HAPs), leading researchers are currently engaged in the design and implementation of tethered unmanned HAPs, which are intended to be long-term operating and are widely used in civilian and military areas. Their possibility of long-term operation, which is one of the main advantages over autonomous UAVs, puts forward new reliability requirements. In this paper we study an analytical reliability model of the multi rotor flight module of the tethered HAP as a homogeneous hot-standby system consisting of n elements operating in a random environment. A general Markov reliability model of the considered system operating in a random environment is proposed, which accounts for the increase in the functional load and the location of the failed components.

关键词： Analytical models Wireless networks Rotors Markov processes Unmanned aerial vehicles Numerical models Telecommunications

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A monitoring campaign (2013-2020) of ESA’s Mars Express to study interplanetary plasma scintillation

arXiv

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arXiv 2023年

作者： Kummamuru, P. Calvés, G. Molera Cimò, G. Pogrebenko, S.V. Bocanegra-Bahamón, T.M. Duev, D.A. Said, M.D. Edwards, J. Ma, M. Quick, J. Neidhardt, A. de Vicente, P. Haas, R. Kallunki, J. Maccaferri, G. Colucci, G. Yang, W.J. Hao, L.F. Weston, S. Kharinov, M.A. Mikhailov, A.G. Jung, T. School of Natural Sciences University of Tasmania Private Bag 37 HobartTAS7005 Australia Joint Institute for VLBI-European Research Infrastructure Consortium Oude Hogeveendijk 4 PD Dwingeloo7991 Netherlands Jet Propulsion Laboratory PasadenaCA United States California Institute of Technology PasadenaCA United States Shanghai Astronomical Observatory 80 Nandan Road Shanghai China Hartebeesthoek Radio Astronomy Observatory Krugersdorp South Africa Technical University of Munich Research Facility Satellite Geodesy Geodetic Observatory Wettzell Sackenrieder Str. 25 Bad Kötzting D-93444 Germany Guadalajara Yebes Spain Chalmers University of Technology Onsala Space Observatory Göteborg Sweden Aalto University Metsöhovi Radio Observatory Kylmälä Finland National Institute for Astrophysics RadioAstronomy Institute Radio Observatory Medicina Italy E-geos S.p.A Space Geodesy Center Italian Space Agency Matera Italy Xinjiang Astronomical Observatory Chinese Academy of Sciences Urumqi China Yunnan Astronomical Observatory Chinese Academy of Sciences Kunming China School of Engineering Computer and Mathematical Sciences Faculty of Design and Creative Technologies Auckland University of Technology New Zealand Institute of Applied Astronomy of Russian Academy of Sciences St Petersburg Russia Korea Astronomy & Space Science Institute 776 Daedeok-daero Yuseong-gu Daejeon Korea Republic of

The radio signal transmitted by the Mars Express (MEX) spacecraft was observed regularly between the years 2013-2020 at X-band (8.42 GHz) using the European Very Long Baseline Interferometry (EVN) network and University of Tasmania’s telescopes. We present a method to describe the solar wind parameters by quantifying the effects of plasma on our radio signal. In doing so, we identify all the uncompensated effects on the radio signal and see which coronal processes drive them. From a technical standpoint, quantifying the effect of the plasma on the radio signal helps phase referencing for precision spacecraft tracking. The phase fluctuation of the signal was determined for Mars’ orbit for solar elongation angles from 0 - 180 deg. The calculated phase residuals allow determination of the phase power spectrum. The total electron content (TEC) of the solar plasma along the line of sight is calculated by removing effects from mechanical and ionospheric noises. The spectral index was determined as –2.43 ± 0.11 which is in agreement with Kolomogorov’s turbulence. The theoretical models are consistent with observations at lower solar elongations however at higher solar elongation (>160 deg) we see the observed values to be higher. This can be caused when the uplink and downlink signals are positively correlated as a result of passing through identical plasma sheets. © 2023, CC BY.

关键词： Solar wind

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Iterative detection for orthogonal time frequency space modulation with unitary approximate message passing

arXiv

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arXiv 2020年

作者： Yuan, Zhengdao Liu, Fei Yuan, Weijie Guo, Qinghua Wang, Zhongyong Yuan, Jinhong The Artificial Intelligence Technology Engineering Research Center Henan Radio & TV University School of Information Engineering Zhengzhou University Zhengzhou450002 China The School of Information Engineering Zhengzhou University Zhengzhou450002 China The School of Electrical Engineering and Telecommunications University of New South Wales NSW2052 Australia The School of Electrical Computer and Telecommunications Engineering University of Wollongong WollongongNSW2522 Australia

The orthogonal-time-frequency-space (OTFS) modulation has emerged as a promising modulation scheme for high mobility wireless communications. To harvest the time and frequency diversity promised by OTFS, some promising detectors, especially message passing based ones, have been developed by taking advantage of the sparsity of the channel in the delay-Doppler domain. However, when the number of channel paths is relatively large or fractional Doppler shifts have to be considered, the complexity of existing detectors is a concern, and the message passing based detectors may suffer from performance loss due to the short loops involved in message passing. In this work, we investigate the design of OTFS detectors based on the approximate message passing (AMP). In particular, leveraging the unitary AMP (UAMP), we design new detectors that enjoy the structure of the channel matrix and allow efficient implementation. In addition, the estimation of noise variance is incorporated into the UAMP-based detectors. Thanks to the robustness of UAMP relative to AMP, the UAMP-based detectors deliver superior performance, and outperform state-of-the-art detectors significantly. We also investigate iterative joint detection and decoding in a coded OTFS system, where the OTFS detectors are integrated into a powerful turbo receiver, leading to considerable performance gains. Copyright © 2020, The Authors. All rights reserved.

关键词： Message passing

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