Author Search Result

[Author] Meng ZHANG(31hit)

21-31hit(31hit)

  • Standard-Compliant Multiple Description Image Coding Based on Convolutional Neural Networks

    Ting ZHANG  Huihui BAI  Mengmeng ZHANG  Yao ZHAO  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2018/07/19
      Vol:
    E101-D No:10
      Page(s):
    2543-2546

    Multiple description (MD) coding is an attractive framework for robust information transmission over non-prioritized and unpredictable networks. In this paper, a novel MD image coding scheme is proposed based on convolutional neural networks (CNNs), which aims to improve the reconstructed quality of side and central decoders. For this purpose initially, a given image is encoded into two independent descriptions by sub-sampling. Such a design can make the proposed method compatible with the existing image coding standards. At the decoder, in order to achieve high-quality of side and central image reconstruction, three CNNs, including two side decoder sub-networks and one central decoder sub-network, are adopted into an end-to-end reconstruction framework. Experimental results show the improvement achieved by the proposed scheme in terms of both peak signal-to-noise ratio values and subjective quality. The proposed method demonstrates better rate central and side distortion performance.

  • An Energy Efficiency 4-bit Multiplier with Two-Phase Non-overlap Clock Driven Charge Recovery Logic

    Yimeng ZHANG  Leona OKAMURA  Tsutomu YOSHIHARA  

     
    PAPER

      Vol:
    E94-C No:4
      Page(s):
    605-612

    A novel charge-recovery logic structure called Pulse Boost Logic (PBL) is proposed in this paper. PBL is a high-speed low-energy-dissipation charge-recovery logic with dual-rail evaluation tree structure. It is driven by 2-phase non-overlap clock, and requires no DC power supply. PBL belongs to boost logic family, which includes boost logic, enhanced boost logic and subthreshold boost logic. In this paper, PBL has been compared with other charge-recovery logic technologies. To demonstrate the performance of PBL structure, a 4-bit pipeline multiplier is designed and fabricated with 0.18 µm CMOS process technology. The simulation results indicate that the 4-bit multiplier can work at a frequency of 1.8 GHz, while the measurement of test chip is at operation frequency of 161 MHz, and the power dissipation at 161 MHz is 772 µW.

  • Mining Approximate Primary Functional Dependency on Web Tables

    Siyu CHEN  Ning WANG  Mengmeng ZHANG  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2018/11/29
      Vol:
    E102-D No:3
      Page(s):
    650-654

    We propose to discover approximate primary functional dependency (aPFD) for web tables, which focus on the determination relationship between primary attributes and non-primary attributes and are more helpful for entity column detection and topic discovery on web tables. Based on association rules and information theory, we propose metrics Conf and InfoGain to evaluate PFDs. By quantifying PFDs' strength and designing pruning strategies to eliminate false positives, our method could select minimal non-trivial approximate PFD effectively and are scalable to large tables. The comprehensive experimental results on real web datasets show that our method significantly outperforms previous work in both effectiveness and efficiency.

  • A Low-Power LDPC Decoder for Multimedia Wireless Sensor Networks

    Meng XU  Xincun JI  Jianhui WU  Meng ZHANG  

     
    PAPER-Fundamental Theories for Communications

      Vol:
    E96-B No:4
      Page(s):
    939-947

    This paper presents a low-power LDPC decoder that can be used in Multimedia Wireless Sensor Networks. Three low power design techniques are proposed in the decoder design: a layered decoding algorithm, a modified Benes network and a modified memory bypassing scheme. The proposed decoder is implemented in TSMC 0.13 µm, 1.2 V CMOS process. Experiments show that when the clock frequency is 32 MHz, the power consumption of the proposed decoder is 38.4 mW, the energy efficiency is 53.3 pJ/bit/ite and the core area is 1.8 mm2.

  • A Fast Chroma Intra-Prediction Mode Decision Algorithm Based on Texture Characteristics for VVC

    Zhi LIU  Yifan SU  Shuzhong YANG  Mengmeng ZHANG  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2021/02/05
      Vol:
    E104-D No:5
      Page(s):
    781-784

    Cross-component linear model (CCLM) chromaticity prediction is a new technique introduced in Versatile Video Coding (VVC), which utilizes the reconstructed luminance component to predict the chromaticity parts, and can improve the coding performance. However, it increases the coding complexity. In this paper, how to accelerate the chroma intra-prediction process is studied based on texture characteristics. Firstly, two observations have been found through experimental statistics for the process. One is that the choice of the chroma intra-prediction candidate modes is closely related to the texture complexity of the coding unit (CU), and the other is that whether the direct mode (DM) is selected is closely related to the texture similarity between current chromaticity CU and the corresponding luminance CU. Secondly, a fast chroma intra-prediction mode decision algorithm is proposed based on these observations. A modified metric named sum modulus difference (SMD) is introduced to measure the texture complexity of CU and guide the filtering of the irrelevant candidate modes. Meanwhile, the structural similarity index measurement (SSIM) is adopted to help judging the selection of the DM mode. The experimental results show that compared with the reference model VTM8.0, the proposed algorithm can reduce the coding time by 12.92% on average, and increases the BD-rate of Y, U, and V components by only 0.05%, 0.32%, and 0.29% respectively.

  • Duty Cycle Corrector for Pipelined ADC with Low Added Jitter

    Zhengchang DU  Jianhui WU  Shanli LONG  Meng ZHANG  Xincun JI  

     
    LETTER

      Vol:
    E92-C No:6
      Page(s):
    864-866

    A wide range, low jitter Duty Cycle Corrector (DCC) based on continuous-time integrator is proposed. It introduces little added jitter in the sampling edge, which make it good candidate for pipelined ADC application. The circuit is implemented in CMOS 0.35 µm 2P4M Mixed Signal process. The experimental results show the circuit can work for a wide frequency range from 500 kHz to 280 MHz, with a correction error within 50%1% under 200 MHz, and the acceptable duty cycle can be as wide as 1-99% for low frequency inputs.

  • HeteroRWR: A Novel Algorithm for Top-k Co-Author Recommendation with Fusion of Citation Networks

    Sufen ZHAO  Rong PENG  Meng ZHANG  Liansheng TAN  

     
    PAPER-Fundamentals of Information Systems

      Pubricized:
    2019/09/26
      Vol:
    E103-D No:1
      Page(s):
    71-84

    It is of great importance to recommend collaborators for scholars in academic social networks, which can benefit more scientific research results. Facing the problem of data sparsity of co-author recommendation in academic social networks, a novel recommendation algorithm named HeteroRWR (Heterogeneous Random Walk with Restart) is proposed. Different from the basic Random Walk with Restart (RWR) model which only walks in homogeneous networks, HeteroRWR implements multiple random walks in a heterogeneous network which integrates a citation network and a co-authorship network to mine the k mostly valuable co-authors for target users. By introducing the citation network, HeteroRWR algorithm can find more suitable candidate authors when the co-authorship network is extremely sparse. Candidate recommenders will not only have high topic similarities with target users, but also have good community centralities. Analyses on the convergence and time efficiency of the proposed approach are presented. Extensive experiments have been conducted on DBLP and CiteSeerX datasets. Experimental results demonstrate that HeteroRWR outperforms state-of-the-art baseline methods in terms of precision and recall rate even in the case of incorporating an incomplete citation dataset.

  • Fast Intra Prediction and CU Partition Algorithm for Virtual Reality 360 Degree Video Coding

    Zhi LIU  Cai XU  Mengmeng ZHANG  Wen YUE  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2018/12/18
      Vol:
    E102-D No:3
      Page(s):
    666-669

    Virtual Reality (VR) 360 degree video has ultra-high definition. Reducing the coding complexity becomes a key consideration in coding algorithm design. In this paper, a novel candidate mode pruning process is introduced between Rough Mode Decision and Most Probable Mode based on the statistical analysis of the intra-coding parameters used in VR 360 degree video coding under Cubemap projection (CMP) format. In addition, updated coding bits thresholds for VR 360 degree video are designed in the proposed algorithm. The experimental results show that the proposed algorithm brings 38.73% and 23.70% saving in average coding time at the cost of only 1.4% and 2.1% Bjontegaard delta rate increase in All-Intra mode and Randomaccess mode, respectively.

  • Fast Coding-Mode Selection and CU-Depth Prediction Algorithm Based on Text-Block Recognition for Screen Content Coding

    Mengmeng ZHANG  Ang ZHU  Zhi LIU  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2016/07/12
      Vol:
    E99-D No:10
      Page(s):
    2651-2655

    As an important extension of high-efficiency video coding (HEVC), screen content coding (SCC) includes various new coding modes, such as Intra Block Copy (IBC), Palette-based coding (Palette), and Adaptive Color Transform (ACT). These new tools have improved screen content encoding performance. This paper proposed a novel and fast algorithm by classifying Code Units (CUs) as text CUs or non-text CUs. For text CUs, the Intra mode was skipped in the compression process, whereas for non-text CUs, the IBC mode was skipped. The current CU depth range was then predicted according to its adjacent left CU depth level. Compared with the reference software HM16.7+SCM5.4, the proposed algorithm reduced encoding time by 23% on average and achieved an approximate 0.44% increase in Bjøntegaard delta bit rate and a negligible peak signal-to-noise ratio loss.

  • An Efficient Multimodal Aggregation Network for Video-Text Retrieval

    Zhi LIU  Fangyuan ZHAO  Mengmeng ZHANG  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2022/06/27
      Vol:
    E105-D No:10
      Page(s):
    1825-1828

    In video-text retrieval task, mainstream framework consists of three parts: video encoder, text encoder and similarity calculation. MMT (Multi-modal Transformer) achieves remarkable performance for this task, however, it faces the problem of insufficient training dataset. In this paper, an efficient multimodal aggregation network for video-text retrieval is proposed. Different from the prior work using MMT to fuse video features, the NetVLAD is introduced in the proposed network. It has fewer parameters and is feasible for training with small datasets. In addition, since the function of CLIP (Contrastive Language-Image Pre-training) can be considered as learning language models from visual supervision, it is introduced as text encoder in the proposed network to avoid overfitting. Meanwhile, in order to make full use of the pre-training model, a two-step training scheme is designed. Experiments show that the proposed model achieves competitive results compared with the latest work.

  • New VVC Chroma Prediction Modes Based on Coloring with Inter-Channel Correlation

    Zhi LIU  Jia CAO  Xiaohan GUAN  Mengmeng ZHANG  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2022/06/27
      Vol:
    E105-D No:10
      Page(s):
    1821-1824

    Inter-channel correlation is one of the redundancy which need to be eliminated in video coding. In the latest video coding standard H.266/VVC, the DM (Direct Mode) and CCLM (Cross-component Linear Model) modes have been introduced to reduce the similarity between luminance and chroma. However, inter-channel correlation is still observed. In this paper, a new inter-channel prediction algorithm is proposed, which utilizes coloring principle to predict chroma pixels. From the coloring perspective, for most natural content video frames, the three components Y, U and V always demonstrate similar coloring pattern. Therefore, the U and V components can be predicted using the coloring pattern of the Y component. In the proposed algorithm, correlation coefficients are obtained in a lightweight way to describe the coloring relationship between current pixel and reference pixel in Y component, and used to predict chroma pixels. The optimal position for the reference samples is also designed. Base on the selected position of the reference samples, two new chroma prediction modes are defined. Experiment results show that, compared with VTM 12.1, the proposed algorithm has an average of -0.92% and -0.96% BD-rate improvement for U and V components, for All Intra (AI) configurations. At the same time, the increased encoding time and decoding time can be ignored.

21-31hit(31hit)

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