The search functionality is under construction.

Author Search Result

[Author] Ziji MA(5hit)

1-5hit
  • Subcarrier and Interleaver Assisted Burst Impulsive Noise Mitigation in Power Line Communication

    Zhouwen TAN  Ziji MA  Hongli LIU  Keli PENG  Xun SHAO  

     
    PAPER-Fundamentals of Information Systems

      Pubricized:
    2020/11/02
      Vol:
    E104-D No:2
      Page(s):
    246-253

    Impulsive noise (IN) is the most dominant factor degrading the performance of communication systems over powerlines. In order to improve performance of high-speed power line communication (PLC), this work focuses on mitigating burst IN effects based on compressive sensing (CS), and an adaptive burst IN mitigation method, namely combination of adaptive interleaver and permutation of null carriers is designed. First, the long burst IN is dispersed by an interleaver at the receiver and the characteristic of noise is estimated by the method of moment estimation, finally, the generated sparse noise is reconstructed by changing the number of null carriers(NNC) adaptively according to noise environment. In our simulations, the results show that the proposed IN mitigation technique is simple and effective for mitigating burst IN in PLC system, it shows the advantages to reduce the burst IN and to improve the overall system throughput. In addition, the performance of the proposed technique outpeformences other known nonlinear noise mitigation methods and CS methods.

  • A Visual Inspection System for Accurate Positioning of Railway Fastener

    Jianwei LIU  Hongli LIU  Xuefeng NI  Ziji MA  Chao WANG  Xun SHAO  

     
    PAPER-Image Recognition, Computer Vision

      Pubricized:
    2020/07/17
      Vol:
    E103-D No:10
      Page(s):
    2208-2215

    Automatic disassembly of railway fasteners is of great significance for improving the efficiency of replacing rails. The accurate positioning of fastener is the key factor to realize automatic disassembling. However, most of the existing literature mainly focuses on fastener region positioning and the literature on accurate positioning of fasteners is scarce. Therefore, this paper constructed a visual inspection system for accurate positioning of fastener (VISP). At first, VISP acquires railway image by image acquisition subsystem, and then the subimage of fastener can be obtained by coarse-to-fine method. Subsequently, the accurate positioning of fasteners can be completed by three steps, including contrast enhancement, binarization and spike region extraction. The validity and robustness of the VISP were verified by vast experiments. The results show that VISP has competitive performance for accurate positioning of fasteners. The single positioning time is about 260ms, and the average positioning accuracy is above 90%. Thus, it is with theoretical interest and potential industrial application.

  • Motion Track Extraction Based on Empirical Mode Decomposition of Endpoint Effect Suppression for Double-Rotor Drone

    Ziji MA  Kehuang XU  Binghang ZHOU  Jiawei ZHANG  Xun SHAO  

     
    PAPER

      Pubricized:
    2019/05/15
      Vol:
    E102-B No:10
      Page(s):
    1967-1974

    Double-rotor drone shows totally different flight performance. Extracting and analyzing its motion track is very helpful to improve its control approaches to achieve a robust and flight attitude. A novel EMD of endpoint effect suppression is proposed in this paper to accurately extract the DR drone's motion track. The proposed algorithm can effectively suppress the endpoint effect with a complex matching of both position and slope of the record of flight data from sensors. The computer simulation and experiment results both have demonstrated the proposed method's effectiveness and the feasibility of the designed DR drone.

  • Impulsive Noise Suppression for ISDB-T Receivers Based on Adaptive Window Function

    Ziji MA  Minoru OKADA  

     
    PAPER-Communication Theory and Signals

      Vol:
    E94-A No:11
      Page(s):
    2237-2245

    Impulsive noise interference is a significant problem for the Integrated Services Digital Broadcasting for Terrestrial (ISDB-T) receivers due to its effect on the orthogonal frequency division multiplexing (OFDM) signal. In this paper, an adaptive scheme to suppress the effect of impulsive noise is proposed. The impact of impulsive noise can be detected by using the guard band in the frequency domain; furthermore the position information of the impulsive noise, including burst duration, instantaneous power and arrived time, can be estimated as well. Then a time-domain window function with adaptive parameters, which are decided in terms of the estimated information of the impulsive noise and the carrier-to-noise ratio (CNR), is employed to suppress the impulsive interference. Simulation results confirm the validity of the proposed scheme, which improved the bit error rate (BER) performance for the ISDB-T receivers in both AWGN channel and Rayleigh fading channel.

  • Channel Pruning via Improved Grey Wolf Optimizer Pruner Open Access

    Xueying WANG  Yuan HUANG  Xin LONG  Ziji MA  

     
    LETTER-Fundamentals of Information Systems

      Pubricized:
    2024/03/07
      Vol:
    E107-D No:7
      Page(s):
    894-897

    In recent years, the increasing complexity of deep network structures has hindered their application in small resource constrained hardware. Therefore, we urgently need to compress and accelerate deep network models. Channel pruning is an effective method to compress deep neural networks. However, most existing channel pruning methods are prone to falling into local optima. In this paper, we propose a channel pruning method via Improved Grey Wolf Optimizer Pruner which called IGWO-Pruner to prune redundant channels of convolutional neural networks. It identifies pruning ratio of each layer by using Improved Grey Wolf algorithm, and then fine-tuning the new pruned network model. In experimental section, we evaluate the proposed method in CIFAR datasets and ILSVRC-2012 with several classical networks, including VGGNet, GoogLeNet and ResNet-18/34/56/152, and experimental results demonstrate the proposed method is able to prune a large number of redundant channels and parameters with rare performance loss.