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Multi-view spectral clustering algorithm based on shared nearest neighbor
SONG Yan, YIN Jun
Journal of Computer Applications    2020, 40 (11): 3211-3216.   DOI: 10.11772/j.issn.1001-9081.2020020228
Abstract432)      PDF (883KB)(518)       Save
In order to solve the problem that the construction of the similarity matrix in the spectral clustering algorithm cannot meet the higher similarity of the data points within the cluster, a Multi-View spectral clustering algorithm based on Shared Nearest Neighbor (MV-SNN) was given. Firstly, the similarity between two data points with a large number of shared neighbors was increased, making the similarity between the data points in the same cluster higher. Then, the improved similarity matrices of multiple views were integrated to obtain a global similarity matrix. Finally, considering that the general spectral clustering methods still need k-means clustering algorithm to divide the data points at the later stage, a rank constraint method of Laplacian matrix was proposed to directly obtain the final cluster structure through the global similarity matrix. Experimental results show that compared with other multi-view spectral algorithms, MV-SNN algorithm has the three measurement standards of clustering:accuracy, purity and normalized mutual information improved by 1%-20%, and the clustering time reduced by about 50%. It can be seen that MV-SNN algorithm can improve the clustering performance and reduce the clustering time.
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Generative adversarial network-based system log-level anomaly detection algorithm
XIA Bin, BAI Yuxuan, YIN Junjie
Journal of Computer Applications    2020, 40 (10): 2960-2966.   DOI: 10.11772/j.issn.1001-9081.2020020270
Abstract740)      PDF (1412KB)(729)       Save
To solve the problems of small number of anomaly samples and inefficient feedback of anomalies in the anomaly detection tasks of large-scale software system, a log-level anomaly detection algorithm based on Generative Adversarial Network (GAN) and attention mechanism. First, the unstructured logs were converted into structured events through the log templates, and each event included timestamps, signature and parameters. Second, through sliding window method, the sequence of the parsed events were divided into patterns, and the real training dataset was comprised combination of the divided event patterns and the corresponding following events. Third, the real event patterns were used as the training samples to train the attention mechanism-based GAN, and the Recurrent Neural Network (RNN) based generator was trained through the adversarial learning mechanism until it converged. Finally, through the input flow event pattern, the generator generated the possibility distribution of normal and abnormal events based on the previous pattern. When the threshold was set, whether the specific log of next moment is a normal event or an abnormal event was determined automatically. Experimental results show that the proposed anomaly detection algorithm, which uses a gated recurrent unit network as the attention weight and a Long Short-Term Memory (LSTM) network to fit event patterns, has a 21.7% increase in precision compared to the algorithm only using the gated recurrent unit network. In addition, compared to the log-level anomaly detection algorithm LogGAN, the proposed algorithm improves the precision of anomaly detection by 7.8% over the performance of LogGAN.
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Parallel multi-layer graph partitioning method for solving maximum clique problems
GU Junhua, HUO Shijie, WU Junyan, YIN Jun, ZHANG Suqi
Journal of Computer Applications    2018, 38 (12): 3425-3432.   DOI: 10.11772/j.issn.1001-9081.2018040934
Abstract572)      PDF (1254KB)(346)       Save
In big data environment, the mass of nodes in graph and the complexity of analysis bring forward higher requirement for the speed and accuracy of maximum clique problems. In order to solve the problems, a Parallel Multi-layer Graph Partitioning method for Solving Maximum Clique (PMGP_SMC) was proposed. Firstly, a new Multi-layer Graph Partitioning method (MGP) was proposed, the large-scale graph partitioning was executed to generate subgraphs while the clique structure of the original graph was maintained and not destroyed. Large-scale subgraphs were divided into multi-level graphs to further reduce the size of subgraphs. The graph computing framework of GraphX was used to achieve MGP to form a Parallel Multi-layer Graph Partitioning (PMGP) method. Then, according to the size of partitioned subgraph, the iteration number of Local Search algorithm Based on Penalty value (PBLS) was reduced, and the PBLS based on Speed optimization (SPBLS) was proposed to solve the maximum clique of each subgraph. Finally, PMGP method and SPBLS were combined to form PMGP_SMC. The large-scale dataset of Stanford was used for running test. The experimental results show that, the proposed PMGP reduces the maximum subgraph size by more than 100 times and the average subgraph size by 2 times compared with Parallel Single Graph Partitioning method (PSGP). Compared with PSGP for Solving Maximum Clique (PSGP_SMC), the proposed PMGP_SMC reduces the overall time by about 100 times, and its accuracy is consistent with that of Parallel Multi-layer Graph Partitioning for solving maximum clique based on Maximal Clique Enumeration (PMGP_MCE) in solving the maximum clique. The proposed PMGP_SMC can solve the maximum clique of large-scale graph quickly and accurately.
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Mobile robot motion estimation based on classified feature points
YIN Jun, DONG Lida, CHI Tianyang
Journal of Computer Applications    2015, 35 (2): 590-594.   DOI: 10.11772/j.issn.1001-9081.2015.02.0590
Abstract591)      PDF (779KB)(348)       Save

In order to solve the real-time problem of visual navigation system with traditional motion estimation algorithm, a new approach based on classified feature points for mobile robot motion estimation was proposed. For dividing feature points into far points and near points, the distances between feature points and mobile robot were calculated according to the 3-dimensional coordinates of feature points. The far points were sensitive to the rotational movement of robot, thus they were used to calculate rotational matrix; the near points were sensitive to translational motion, thus they were used to calculate the translational matrix. When the far points and the near points are 30% of original feature points, the proposed approach had equivalent accuracy but reduced 60% computing time compared with RANdom SAmple Consensus (RANSAC). The results demonstrate that, by using classified feature points, the proposed algorithm can effectively reduce computing time, meanwhile ensure accuracy of motion estimation, and it can meet the the real-time requirement with large feature points.

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Similarity matching selection of genetic algorithm
XIE Zhi-wen,YIN Jun-xun,JIN Jing
Journal of Computer Applications    2005, 25 (11): 2665-2667.  
Abstract1778)      PDF (618KB)(1163)       Save
A new matching selection called similarity-matching selection of genetic algorithm was presented and the probabilities of the selection were calculated.An experimental calculation based on the proposed matching selection for a maximum problem was performed.The results show that such a matching selection guarantees the centralization and continuity of the excellent genes and can help to maintain the good gene constructions from the point of real world’s view.Furthermore,from the point of calculation convergence view,the calculation using the new matching selection is not easy to diverge in the small area around the global maximum.Therefore,the speed of convergence can be accelerated.
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Research of Ad hoc network structure
LI Yong,HUANG Jun-cai,WANG Feng-bi, YIN Jun-xun
Journal of Computer Applications    2005, 25 (01): 163-164.   DOI: 10.3724/SP.J.1087.2005.0163
Abstract1183)      PDF (164KB)(2353)       Save

The network structure design for Ad hoc is different from those of the traditional ones. The node structure was expounded and some typical network structures were compared firstly. Then a kind of protocol stack for Ad hoc was given. Different from other models, there was a middleware layer between transmission layer and net layer in this model, which shielded the OS and network’s low layers details and enhanced the reliability and security of communications at the same time.

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