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  • IOP Publishing  (8)
  • Wang, Jie  (8)
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  • IOP Publishing  (8)
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  • 1
    Online Resource
    Online Resource
    Research on Channelization Techniques of Radio Astronomical Wideband Signal with Oversampled Polyphase Filter Banks
    IOP Publishing ; 2023
    In:  Research in Astronomy and Astrophysics Vol. 23, No. 8 ( 2023-08-01), p. 085012-
    Details
    In: Research in Astronomy and Astrophysics, IOP Publishing, Vol. 23, No. 8 ( 2023-08-01), p. 085012-
    Abstract: Digital channelization decomposes a wideband signal into multiple adjacent sub-bands using Parallel Technology. Channelization can effectively reduce the pressure on the radio astronomy digital backends system and make wideband signal processing possible. Aiming at the problems of signal attenuation at sub-band edge, spectral leakage and aliasing encountered in wideband signal channelization, algorithms to reduce the problems are studied. We design a Critically Sampled Polyphase Filter Bank (CS-PFB) based on the Finite Impulse Response digital filter with a Hamming Window and systematically analyze the frequency response characteristics of the CS-PFB. Based on the channelized structure of the CS-PFB, an OverSampled Polyphase Filter Bank (OS-PFB) is designed by data reuse, and the filtering frequency response characteristics of CS-PFB and OS-PFB are compared and analyzed. Using the wideband baseband data generated by the CASPSR (Collaboration for Astronomy Signal processing and electronics research Parkes Swinburne Recorder), we implement sub-band division and 16-band output of these data based on the 2× oversampling OS-PFB, and the problem of spectrum inversion in the sub-bands is corrected. After removing 25% of redundant data in the head and tail of each sub-band, we recombine the sub-bands into a wideband. The wideband signal is almost identical to the original observed signal. Therefore, the experimental results show that the OS-PFB can improve the channel response. For the 400 MHz baseband data of J0437-4715, we compare the pulse profile obtained from the original baseband data with the pulse profile obtained after the channelization and recombination. The phase and amplitude information of the pulse profiles are consistent, which verifies the correctness of our channelization algorithm.
    Type of Medium: Online Resource
    ISSN: 1674-4527
    URL: Article
    DOI: 10.1088/1674-4527/acd73b
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 2511247-8
    SSG: 6,25
    SSG: 16,12
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    Online Resource
  • 2
    Online Resource
    Online Resource
    Research on Voltage Stabilization Technology for Long-distance Energy Transmission in Orbit
    IOP Publishing ; 2022
    In:  Journal of Physics: Conference Series Vol. 2401, No. 1 ( 2022-12-01), p. 012009-
    Details
    In: Journal of Physics: Conference Series, IOP Publishing, Vol. 2401, No. 1 ( 2022-12-01), p. 012009-
    Abstract: For large spacecraft such as space stations and spacecraft, due to their huge systems, when the power supply equipment and electrical equipment are remote away, it is necessary to lay a long power supply cable. Therefore, when high-power energy transmission is carried out, the voltage drop of the cable will cause the terminal voltage of the electrical equipment to fluctuate with the transmission power. This will have an impact on some load equipment with high demand for electricity, and even shorten the service life of the equipment. In order to ensure the stability of terminal voltage and controllable amplitude of fluctuation, this paper proposes a voltage stabilization technology for long-distance energy transmission in orbit, and the principle analysis, simulation, and experimental verification are carried out to confirm the effectiveness of the technology.
    Type of Medium: Online Resource
    ISSN: 1742-6588 , 1742-6596
    URL: Article
    DOI: 10.1088/1742-6596/2401/1/012009
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 2166409-2
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    Online Resource
  • 3
    Online Resource
    Online Resource
    Investigation of Traffic Classification Applied to an Astronomical Data Transmission Network of the XAO Using Deep Learning
    IOP Publishing ; 2023
    In:  Research in Astronomy and Astrophysics Vol. 23, No. 3 ( 2023-03-01), p. 035003-
    Details
    In: Research in Astronomy and Astrophysics, IOP Publishing, Vol. 23, No. 3 ( 2023-03-01), p. 035003-
    Abstract: A telecommunication network used for the transmission of astronomical observation data, telescope remote control and other astronomical research purposes is a critical infrastructure. The monitoring and analysis of network traffic, which help improve the network performance and the utilization of network resources, are a challenging task. The accurate identification of the astronomical data traffic will effectively improve transmission efficiency. In this paper, a classification method applied to types of traffic containing astronomical data using deep learning is proposed. The advantages of a convolutional neural network model in image classification are exploited to classify types of traffic containing astronomical data. The objective is to identify the mixed traffic in the network and accurately identify types of traffic containing astronomical data. The effectiveness of the model in improving classification accuracy is also discussed. Actual traffic data captured by Tcpdump and Wireshark are tested, and the experimental results indicate that the proposed method can accurately classify types of traffic containing astronomical data.
    Type of Medium: Online Resource
    ISSN: 1674-4527
    URL: Article
    DOI: 10.1088/1674-4527/acafc5
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 2511247-8
    SSG: 6,25
    SSG: 16,12
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    Online Resource
  • 4
    Online Resource
    Online Resource
    Simulation analysis of a method to improve data-transmission performance of Nanshan 26m Radio Telescope based on Software-Defined Networks
    IOP Publishing ; 2021
    In:  Research in Astronomy and Astrophysics Vol. 21, No. 11 ( 2021-12-01), p. 279-
    Details
    In: Research in Astronomy and Astrophysics, IOP Publishing, Vol. 21, No. 11 ( 2021-12-01), p. 279-
    Abstract: Data Center of Xinjiang Astronomical Observatory (XAO-DC) commenced operating in 2015, and provides services including archiving, releasing and retrieving precious astronomical data collected by the Nanshan 26m Radio Telescope (NSRT) over the years, and realises the open sharing of astronomical observation data. The observation data from NSRT are transmitted to XAO-DC 100 km away through dedicated fiber for long-term storage. With the continuous increase of data, the static architecture of the current network cannot meet NSRT data-transmission requirements due to limited network bandwidth. To get high-speed data-transmission using the existing static network architecture, a method for reconstruction data-transmission network using Software-Defined Networks (SDN) is proposed. Benefit from the SDNʼs data and control plane separation, and open programmable, combined with the Mininet simulation platform for experiments, the TCP throughput (of single thread) was improved by ∼24.7%, the TCP throughput (of multi threads) was improved by ∼9.8%, ∼40.9%, ∼35.5% and ∼11.7%. Compared with the current network architecture, the Latency was reduced by ∼63.2%.
    Type of Medium: Online Resource
    ISSN: 1674-4527
    URL: Article
    DOI: 10.1088/1674-4527/21/11/279
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2511247-8
    SSG: 6,25
    SSG: 16,12
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    Online Resource
  • 5
    Online Resource
    Online Resource
    PHoTo N s–A parallel heterogeneous and threads oriented code for cosmological N -body simulation
    IOP Publishing ; 2018
    In:  Research in Astronomy and Astrophysics Vol. 18, No. 6 ( 2018-06), p. 062-
    Details
    In: Research in Astronomy and Astrophysics, IOP Publishing, Vol. 18, No. 6 ( 2018-06), p. 062-
    Type of Medium: Online Resource
    ISSN: 1674-4527
    URL: Article
    DOI: 10.1088/1674-4527/18/6/62
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2018
    detail.hit.zdb_id: 2511247-8
    SSG: 6,25
    SSG: 16,12
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    Online Resource
  • 6
    Online Resource
    Online Resource
    Research on a Coherent Dedispersion Algorithm for Pulsar Baseband Data
    IOP Publishing ; 2023
    In:  Research in Astronomy and Astrophysics Vol. 23, No. 1 ( 2023-01-01), p. 015023-
    Details
    In: Research in Astronomy and Astrophysics, IOP Publishing, Vol. 23, No. 1 ( 2023-01-01), p. 015023-
    Abstract: When the pulsar signal propagates in the interstellar medium (ISM), the high frequency and low frequency components of the signal reach the radio telescope with a certain delay. Therefore, the pulsar signal will appear energy dispersion, which will broaden the pulse profile, decrease the signal to noise ratio, and even lead to the disappearance of the pulse signal. In this paper, we analyze the sampling, polarization and arrangement of baseband data based on the coherent dedispersion algorithm for the problem of pulsar baseband data dedispersion. We systematically study the coherent dedispersion data processing procedure, and test the pulse profile changes under different FFT block sizes. An optimal selection strategy of FFT block sizes is proposed for reducing the operation time and obtaining a better pulse profile. We propose two methods, one is the generation of ISM transfer function, the other is the pulsar period and phase prediction method at a certain time, and discuss integral and folding strategies. We test the algorithm based on the baseband data of CASPSR and Medusa terminals observed by the Parkes 64 m radio telescope, and analyze the reading and processing methods of baseband data of different terminals. The experimental results show that the phase and amplitude information of the pulse profile processed by our algorithm is basically consistent with the results obtained by DSPSR.
    Type of Medium: Online Resource
    ISSN: 1674-4527
    URL: Article
    DOI: 10.1088/1674-4527/aca8ee
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 2511247-8
    SSG: 6,25
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 7
    Online Resource
    Online Resource
    Numerical study of the stopping distance for runaway vehicle on truck escape ramp by using the improved equation of car driving
    IOP Publishing ; 2019
    In:  IOP Conference Series: Materials Science and Engineering Vol. 542, No. 1 ( 2019-06-01), p. 012021-
    Details
    In: IOP Conference Series: Materials Science and Engineering, IOP Publishing, Vol. 542, No. 1 ( 2019-06-01), p. 012021-
    Abstract: The stopping distance of the runaway vehicle on the mountain road directly affects the length design of the arrester bed. Since the subsidence depth of runaway vehicle wheel on the arrester bed is neglected in the past researches, the stopping distance estimated by the vehicle driving equation is not accurate. The purpose of this paper is to supplement the influence of subsidence depth on rolling resistance and the influence of mountain highway altitude on air resistance, and improve the estimation accuracy through improved vehicle driving equation. Firstly, the formula for fitting the subsidence depth is established, and the formula for calculating the pushing resistance and compaction resistance is added. Considering the influence of the altitude of the mountain road on the air resistance, the formula for calculating the corrected air resistance and the air lift is added too and the improved vehicle driving equation is generated. Secondly, a simulink model is established based on the improved vehicle driving equation and determine the attester bed entering position and the initial entering speed of the runaway vehicle. Finally, the simulation model is run and analysed. The results show that the error rate of the simulation results is less than 8.0% compared with the full-scale test data. Compared with original equation, the shortening rate of the stopping distance is up to 85.59%.
    Type of Medium: Online Resource
    ISSN: 1757-8981 , 1757-899X
    URL: Article
    DOI: 10.1088/1757-899X/542/1/012021
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2019
    detail.hit.zdb_id: 2506501-4
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    Online Resource
  • 8
    Online Resource
    Online Resource
    Simulation Study of Network Reconfiguration and Load-balancing Method for the Xinjiang Astronomical Observatory Data Center
    IOP Publishing ; 2022
    In:  Research in Astronomy and Astrophysics Vol. 22, No. 9 ( 2022-09-01), p. 095022-
    Details
    In: Research in Astronomy and Astrophysics, IOP Publishing, Vol. 22, No. 9 ( 2022-09-01), p. 095022-
    Abstract: The Xinjiang Astronomical Observatory Data Center faces issues related to delay-affected services. As a result, these services cannot be implemented in a timely manner due to the overloading of transmission links. In this paper, the software-defined network technology is applied to the Xinjiang Astronomical Observatory Data Center Network (XAO-DCN). Specifically, a novel reconfiguration method is proposed to realise the software-defined Xinjiang Astronomical Observatory Data Center Network (SDXAO-DCN), and a network model is constructed. To overcome the congestion problem, a traffic load-balancing algorithm is designed for fast transmission of the service traffic by combining three factors: network structure, congestion level and transmission service. The proposed algorithm is compared with current commonly load-balancing algorithms which are used in data center to verify its efficiency. Simulation experiments show that the algorithm improved transmission performance and transmission quality for the SDXAO-DCN.
    Type of Medium: Online Resource
    ISSN: 1674-4527
    URL: Article
    DOI: 10.1088/1674-4527/ac846a
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 2511247-8
    SSG: 6,25
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
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