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Multiply distortion type judgement method based on multi-scale and multi-classifier convolutional neural network
Junhua YAN, Ping HOU, Yin ZHANG, Xiangyang LYU, Yue MA, Gaofei WANG
Journal of Computer Applications    2021, 41 (11): 3178-3184.   DOI: 10.11772/j.issn.1001-9081.2020121894
Abstract329)   HTML9)    PDF (1034KB)(112)       Save

It is difficult to judge the image multiply distortion type. In order to solve the problem, based on the idea of deep learning multi-label classification, a new multiply distortion type judgement method based on multi-scale and multi-classifier Convolutional Neural Network (CNN) was proposed. Firstly, the image block containing high-frequency information was obtained from the image, and the image block was input into the convolution layers of different receptive fields to extract the shallow feature maps of the image. Then, the shallow feature maps were input into the structure of each sub-classifier for deep feature extraction and fusion, and the fused features were judged by the Sigmoid classifier. Finally, the judgment results of different sub-classifiers were fused to obtain the multiply distortion type of image. Experimental results show that, on the Natural Scene Mixed Disordered Images Database (NSMDID), the average judgment accuracy of the proposed method can reach 91.4% for different types of multiply distortion types in the images, and most of them are above 96.8%, illustrating that the proposed method can effectively judge the types of distortion in multiply distortion images.

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E-learning resource library model based on domain ontology
ZHANG Hu-yin ZHANG Ming-yang LI Xin
Journal of Computer Applications    2012, 32 (01): 191-195.   DOI: 10.3724/SP.J.1087.2012.00191
Abstract1154)      PDF (801KB)(639)       Save
With the rapid development of E-learning system, E-learning resources grow explosively. How to effectively organize E-learning resources is a key factor of constructing efficient E-learning system. Concerning the existing resources organization deficiency of E-learning resource library, this paper proposed an E-learning resource retrieval model based on domain ontology. This model built a domain knowledge library by making use of the domain knowledge and constructed E-learning resources metadata database by extracting resources metadata, realized semantic organization of E-learning resources through mapping relations, and constructed a semantic retrieval model on this basis, in order to effectively solve the problem of the loss of semantic background in the E-learning resource retrieving. The model has also enhanced the recall rate and the precision rate on the retrieval results, and it is more in line with the needs of the users.
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Improved M-virtual scanning algorithm for road surveillance
SU Pan-lan CHEN Liang-yin ZHANG Jing-yu YUAN Ping
Journal of Computer Applications    2011, 31 (12): 3187-3190.  
Abstract888)      PDF (601KB)(717)       Save
VIrtual Scanning Algorithm(VISA) is unable to fully take advantage of the number of nodes, in order to prolong the network lifetime, it must be built on the basis of dense nodes deployment which makes the time for finding average target increase. Therefore, based on low dutycycle Wireless Sensor Network (WSN) by combining the ideology of virtual scan wave, the Multiple VIrtual Scan Algorithm (M-VISA) was proposed for road surveillance. This algorithm adopted the way of fixing points, deploying the same location with multinodes to let the nodes to be worked in order and in batches, hence, the network lifetime could be greatly extended. Simulation result demonstrates that M-VISA can prolong network lifetime by 180% when compared with VISA, improving the network performance effectively.
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Method of weather recognition based on decision-tree-based SVM
Li Qian FAN Yin ZHANG Jing LI BAOqiang
Journal of Computer Applications    2011, 31 (06): 1624-1627.   DOI: 10.3724/SP.J.1087.2011.01624
Abstract2717)      PDF (620KB)(830)       Save
To improve the quality of video surveillance outdoors and to automatically acquire the weather situations, a method to recognize weather situations in outdoor images is presented. It extracted such parameters as power spectrum slope, contrast, noise, saturation as features to realize the multi-classification of weather situations with Support Vector Machine (SVM). Then a decision tree was constructed in accordance with the distance between these features. The experimental results on WILD image base and our image set of eight hundred samples show that the proposed method can recognize sunny, overcast, foggy weather more than 85%, and recognize rainy weather more than 75%.
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Hybrid model applied in authentication of grid security
Chun-ling CHENG Deng-yin ZHANG
Journal of Computer Applications   
Abstract1519)      PDF (862KB)(811)       Save
This paper made a systematic analysis on a few of current trust models, provided a new mixed authenticated trust model, and gave a particular frame and function design. Then the study carried out a simulation and property analysis of the new model. The simulation results indicate that the new mixed authentication model can resolve the defaults of the static key mechanism and improve the security of the grid authentication.
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Using uncertainty DHT to solve non-transitive connectivity problems in overlay network
WANG Xiang-Hui 王向辉 Guo-Yin ZHANG
Journal of Computer Applications   
Abstract2070)      PDF (768KB)(929)       Save
In order to resolve the widely existing problem of Non-Transitive Connectivity (NTC) in networks, a uncertainty Distributed Hash Tables (DHT) method to resolve the NTC problem in overlay network was proposed. The relationship of bottom node ID and logical space location was lifted to avoid infection of network structure by NTC nodes, and redirection route mechanism was used to implement the message routing of network. Simulation shows that uncertainty DHT could effectively resolve the NTC problem in overlay network.
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