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Single image super-resolution method based on non-local channel attention mechanism
YE Yang, CAI Qiong, DU Xiaobiao
Journal of Computer Applications    2020, 40 (12): 3618-3623.   DOI: 10.11772/j.issn.1001-9081.2020050681
Abstract438)      PDF (1173KB)(497)       Save
Single image super-resolution is an ill-posed problem, which aims to reconstruct the texture pattern with the given blurry and low-resolution image. Recently, Convolution Neural Network (CNN) was introduced into the field of super-resolution. Although excellent performance was obtained by current studies through designing the structure and the connection way of CNN, the use of edge data for training more powerful model was ignored. Therefore, a method based on edge data enhancement, that is, Non-local Channel Attention (NCA) method for single image super-resolution was proposed. The proposed method can make full use of the training data and improve performance by non-local channel attention. Not only the guideline to design the network was provided by the proposed method, but also the interpretation of super-resolution task was able to be performed by using the proposed method. The NCA Network (NCAN) model was composed of main branch and edge enhancement branch. The main branch self-attention was made for reconstructing the super-resolution images by taking the low-resolution images as input of the model and predicting the edge data. Experimental results show that, compared with the Second-order Attention Network (SAN) model, NCAN has the Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity (SSIM) improved by 0.21 dB and 0.009 respectively on the benchmark dataset BSD100 at the magnification factor of 3; compared with the deep Residual Channel Attention Network (RCAN) model, NCAN has the PSNR and SSIM significantly improved on benchmark datasets of Set5 and Set14 at the magnification factor of 3 and 4. NCAN outperforms the state-of-the-art models on comparable parameters.
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Design of live video streaming, recording and storage system based on Flex, Red5 and MongoDB
ZHEN Jingjing YE Yan LIU Taijun DAI Cheng WANG Honglai
Journal of Computer Applications    2014, 34 (2): 589-592.  
Abstract619)      PDF (632KB)(731)       Save
In order to improve the conventional situation that network video does not play smoothly during live or on-demand and find storage strategy of mass video data, this paper presented an overall design scheme of a real-time live video recording and storage system. The open source streaming media server Red5 and the rich Internet application technology Flex were utilized to achieve live video streaming and recording. The recorded video data would be stored in the open source NoSQL database MongoDB. The experimental results illustrate that the platform can meet requirements of multi-user access and data storage.〖JP〗
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Nonlinear modeling of power amplifier based on improved radial basis function networks
LI Ling LIU Taijun YE Yan LIN Wentao
Journal of Computer Applications    2014, 34 (10): 2904-2907.   DOI: 10.11772/j.issn.1001-9081.2014.10.2904
Abstract257)      PDF (535KB)(358)       Save

Aiming at the nonlinear modeling of Power Amplifier (PA), an improved Radial Basis Function Neural Networks (RBFNN) model was proposed. Firstly, time-delay of cross terms and output feedback were added in the input. Parameters (weigths and centers) of the proposed model were extracted using the Orthogonal Least Square (OLS) algorithm. Then Doherty PA was trained and validated successfully by 15MHz three-carrier Wideband Code Division Multiple Access (WCDMA) signal, and the Normalized Mean Square Error (NMSE) can reach -45dB. Finally, the inverse class F power amplifier was used to test the universality of the model. The simulation results show that the model can more truly fit characteristics of power amplifier.

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Taxi gathering area recognition algorithm based on sample weight
JI Bo YE Yangdong LU Hongxing
Journal of Computer Applications    2013, 33 (05): 1338-1342.   DOI: 10.3724/SP.J.1087.2013.01338
Abstract1096)      PDF (732KB)(761)       Save
Dynamic, random and asynchronous taxi objects can be grouped by clustering methods. However, the traditional clustering methods treat all taxi samples equally and set weights of all samples without distinction when evaluating similarity. However, not all of the features are important to the clustering judgment. Therefore, the paper proposed a taxi gathering area recognition SFTA-IB algorithm based on sample weight. The SFTA-IB algorithm introduced sample weight to reveal the contribution level of different samples. Then, the SFTA-IB algorithm considered the taxis as the original variable X, the GPS data as the relevant variable Y. The goal was to find a compressed representation T, which was as informative as possible about Y. The experimental results show that the proposed SFTA_IB algorithm can identify the taxi gathering areas for one specified taxi, supervise the cruise strategy and improve the passenger searching efficiency.
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