Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-05-10 Cooperative journals: 《计算机应用研究》
Abstract： Multi-pattern matching plays an important role in network intrusion detection and content filtering. To solve the deficiency of Wu-Manber multi-pattern matching algorithm in terms of the achieved matching efficiency and jump distance, propose an improved Wu-Manber algorithm for Chinese PDF document content revciew on the basis of the coding formats of PDF document content. By employing the Bloom filter to extract the curcial information of the pattern string, and exploiting the double hash and PDF document encoding rules, it is shown that the proposed improved algorithm is able to reduce the number of unnecessary matches and increase the jump distance, thus improving the matching efficiency for the content retrieval of PDF document. The practical experimental results confirms the improved matching efficiency for PDF document. When the shortest mode string is long and the mode string size is large, the matching efficiency can be even doubled.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-01-03 Cooperative journals: 《计算机应用研究》
Abstract： In order to enhance the access control ability of HBase, this paper proposed a fine-grained access control method for HBase. This method achieves the purpose of fine-grained access control by modifying and optimizing the HBase source code, extending the access control permissions, and rewriting the AccessController. Moreover, this paper generalizes the RBAC model that applied in HBase, and use built-in database roles to solve the problem that fine-grained permissions management becomes more difficult after extending permissions. By designing experimental test cases, it is verified that the proposed fine-grained access control method can protect HBase data more comprehensively. This paper solves the problem that excessive permissions caused by the original method, and reduces the huge security risk caused by data may be maliciously performing operations such as modification and deletion, etc.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-09-12 Cooperative journals: 《计算机应用研究》
Abstract： Reliable scene analysis, which commonly involves vehicle identification, pedestrian detection, and collision avoidance, u, is an essential technique in realizing automatic driving of intelligent vehicle. This paper proposes a stereo vision multi-object tracking method based on joint probabilistic data association (JPDA) filter for intelligent vehicle: the method collects the images and videos of vehicles and pedestrians with the help of stereo camera mounted on top of a vehicle, model the uncertainty of sensor in Lie group, and adopt the Euclidean algorithm to implement state-filtering for the preprocessed images. Utilize the improved JPDA to rectified the tracking of vehicles and pedestrians. Experiment results show that the proposed method can settle the tracking of multi-objects effectively, and improve the level of automation and intelligence for driving system dramatically. Compared with other new target tracking methods, the proposed method has obvious advantages in tracking precision and speed. It does not produce obvious offset in tracking the vehicle and will not miss the tracking of pedestrians.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-08-13 Cooperative journals: 《计算机应用研究》
Abstract： With the increasing number of the vehicles, the intelligent transportation system requires accurately and quickly detect vehicles in videos under complex conditions. Hence, this paper proposed an efficient vehicles detection scheme basing on the existing works. Firstly, it selected a pixel based adaptive segmentation algorithm to linearly optimize its background model, which could reduce the compute complexity and extract the foreground spot as Defined Range Approach. Then, it used threshold determination to determine the region of interest; In the region of interest, it selected the Haar-like features and histogram of oriented gradient (HOG) features and used them as input of the optimized AdaBoost + support vector machine (SVM) cascade classifier for vehicles detection. The proposed algorithm used the OpenCV library. These methods guarantee the real-time performance of the algorithm. The substancial experiments demonstrated the superiority of the linearized Pixel Based Adaptive Segmentation, the rapidity of the Adaboost+Support Vector Machine cascaded classifier, and the real-time processing abality and the illumination robustness of the overall vehicle detection algorithm in detecting vehicles.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-20 Cooperative journals: 《计算机应用研究》
Abstract： In order to take into account the fidelity and computational efficiency of cloth simulation, this paper presented a construction method of multi-resolution cloth based on low-resolution cloth sampling. Firstly, through sampling a simulation example of low-resolution cloth movement several times, this paper obtained the average deformation degree, which represented by the average deformation degree of the vertex and the edge collision mark. Then, according to the results of sampling, it divided the region of low-resolution into high deformation area, middle deformation area and low deformation area. Next, it used the improved adaptive subdivision algorithm to refine the three deformation areas in different extent, so as to construct the multi-resolution geometric model. Finally, through the definition of the mass and the spring coefficient of the cloth, it obtained the multi-resolution physical model. This paper reduces multi-resolution grid number and improves computational efficiency relative to the high-resolution grid. It also improves the fidelity of cloth simulation compare to the low-resolution grid.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-20 Cooperative journals: 《计算机应用研究》
Abstract： To realize the rapid collision detection between cloth and human body in cloth simulation, a collision detection method based on ellipsoid fitting is proposed. Firstly, the geometric distance isoline was used as the basic data. And the model feature points was extracted by combining the linear relationship between body size and height with the structural features of the human body, which realized the semantic segmentation of the model. Secondly, the average of the radial distance was used to represent the fitting error between an ellipsoid and the model. And the number of cluster centers was gradually increased by bisecting K-means clustering algorithm based on pruning optimization. It could realize the rapid clustering of human model and generate a series of minimum ellipsoids. Finally, cloth grid points was detected with the ellipsoids instead of the model. Simulation experiments show that this method not only realizes the fast fitting of the human model, but also effectively improves the computational efficiency of collision detection.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-12 Cooperative journals: 《计算机应用研究》
Abstract： In order to solve the problem of cold start and data sparsity for traditional collaborative filtering recommendation algorithm, and the accuracy of similarity measurement, this paper proposed a matrix decomposition recommendation algorithm based on the LDA theme model. Firstly, it uses the improved LDA algorithm to output the project-topic distribution, using the perplexity as the modified function of the subject number; Secondly, it calculate the similarity matrix of the project based on the cosine similarity and the KL divergence, combineing the obtained similarity matrix with the original scoring training set to output the pre score, and then fills the preliminary score to the training set. Finally, it input the training set to ALS matrix decomposition algorithm to get the recommended results. The experimental results of the MovieLens data set show that the proposed algorithm can get a smaller MAE values than the traditional ALS algorithm under different implicit parameter settings and it greater than traditional recommdation algorithm . The experiment shows that the results of the ALS algorithm are better than other algorithms by integrating the LDA theme model.
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