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Fast link failure recovery method for software-defined internet of vehicles
Yuan GU, Zhen ZHANG, Tong DUAN
Journal of Computer Applications    2023, 43 (3): 853-859.   DOI: 10.11772/j.issn.1001-9081.2022010058
Abstract273)   HTML5)    PDF (2543KB)(70)       Save

Aiming at the single link failure problem in the vehicle-road real-time query communication scenario of Software-Defined Internet of Vehicles (SDIV), a fast link failure recovery method for SDIV was proposed, which considered link recovery delay and path transmission delay after link recovery. Firstly, the failure recovery delay was modeled, and the optimization goal of minimizing the delay was transformed into a 0-1 integer linear programming problem. Then, this problem was analyzed, two algorithms were proposed according to different situations, which tried to maximize the reuse of the existing calculation results. In specific, Path Recovery Algorithm based on Topology Partition (PRA-TP) was proposed when the flow table update delay was not able to be ignored compared with the path transmission delay, and Path Recovery Algorithm based on Single Link Search (PRA-SLS) was proposed when the flow table update delay was negligible because being farless than the path transmission delay. Experimental results show that compared with Dijkstra algorithm, PRA-TP can reduce the algorithm calculation delay by 25% and the path recovery delay by 40%, and PRA-SLS can reduce the algorithm calculation delay by 60%, realizing fast single link failure recovery at vehicle end.

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Fireworks algorithm for location-routing problem of simultaneous pickup and delivery with time window
Yaping LIU, Huizhen ZHANG, Li ZHANG, Youyou LIU
Journal of Computer Applications    2022, 42 (7): 2292-2300.   DOI: 10.11772/j.issn.1001-9081.2021040697
Abstract219)   HTML6)    PDF (2162KB)(54)       Save

With the rapid development of e-commerce and the popularity of the Internet, it is more convenient to exchange and return goods. Therefore, the customers’ demands for goods show the characteristics of timeliness, variety, small batch, exchanging and returning. Aiming at Location-Routing Problem with Simultaneous Pickup and Delivery (LRPSPD) with capacity and considering the characteristics of customers’ diversified demands, a mathematical model of LRPSPD & Time Window (LRPSPDTW) was established. Improved FireWorks Algorithm (IFWA) was used to solve the model, and the corresponding neighborhood operations were carried out for the fireworks explosion and mutation. The performance of the fireworks algorithm was evaluated with some benchmark LRPSPD examples. The correctness and effectiveness of the proposed model and algorithm were verified by a large number of numerical experiments. Experimental results show that compared with Branch and Cut algorithm (B&C), the average error between the result of IFWA and the standard solution is reduced by 0.33 percentage points. The proposed algorithm shortens the time to find the optimal solution, and provides a new way of thinking for solving location-routing problems.

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Multi-document sentiment summarization based on latent Dirichlet Allocation model
XUN Jing LIU Peiyu YANG Yuzhen ZHANG Yanhui
Journal of Computer Applications    2014, 34 (6): 1636-1640.   DOI: 10.11772/j.issn.1001-9081.2014.06.1636
Abstract273)      PDF (706KB)(603)       Save

It is difficult for the existing methods to get overall sentiment orientation of the comment text. To solve this problem, the method of multi-document sentiment summarization based on Latent Dirichlet Allocation (LDA) model was proposed. In this method, all the subjective sentences were extracted by sentiment analysis and described by LDA model, then a summary was generated based on the weight of sentences which combined the importance of words and the characteristics of sentences. The experimental results show that this method can effectively identify key sentiment sentences, and achieve good results in precision, recall and F-measure.

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Transmission and scheduling scheme based on W-learning algorithm in wireless networks
ZHU Jiang PENG Zhenzhen ZHANG Yuping
Journal of Computer Applications    2013, 33 (11): 3005-3009.  
Abstract494)      PDF (973KB)(355)       Save
To solve the problem of transmission in wireless networks, a transmission and scheduling scheme based on W-learning algorithm in wireless networks was proposed in this paper. Building the system model based on Markov Decision Progress (MDP), with the help of W-learning algorithm, the goal of using this scheme was to transmit intelligently, namely, the package loss under the premise of energy saving by choosing which one to transmit and the transmit mode legitimately was reduced. The curse of dimensionality was overcome by state aggregate method, and the number of actions was reduced by action set reduction scheme. The storage space compression ratio of successive approximation was 41%; the storage space compression ratio of W-learning algorithm was 43%. Finally, the simulation results were given to evaluate the performances of the scheme, which showed that the proposed scheme can transport data as much as possible on the basis of energy saving, the state aggregation method and the action set reduction scheme can simplify the calculation with little influence on the performance of algorithms.
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Solution to complex container loading problem based on ant colony algorithm
Li-ning DU De-zhen ZHANG Shi-feng CHEN
Journal of Computer Applications    2011, 31 (08): 2275-2278.   DOI: 10.3724/SP.J.1087.2011.02275
Abstract1927)      PDF (687KB)(941)       Save
In view of the complex Container Loading Problem (CLP), the optimal loading plan with heuristic information and the ant colony algorithm was proposed. Firstly, a mathematical model was generated. Considering the strong search ability, potential parallelism and scalability of ant colony algorithm, the proposed algorithm was combined with the triple-tree structure to split the layout of space in turn. Then, the three-dimensional rectangular objects of different sizes were placed to the layout space under the constraints. An ant colony algorithm based on spatial partition was designed to solve the optimal procedure. Finally, a design example that 700 pieces of goods were loaded into a 40-foot (12.025m) high cubic was calculated. The experimental results show that the proposed method can enhance the utilization of the container and it has a strong practicality.
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Task allocation and scheduling algorithm based on dynamic dual-directional priority
Yue GONG Zhen-zhen ZHANG Xiao-ke HUANG Jian-jun LIU
Journal of Computer Applications   
Abstract1227)      PDF (724KB)(816)       Save
A task allocation and scheduling algorithm called Dynamic Dual-Directional Priority (DDDP) was presented. This algorithm considered the priority of real-time task and the sub synthetically, and constructed a dynamic dual-directional priority task allocation model, realized the task allocation and scheduling of the master/sub model in data transmission. In the simulation experiments with some typical data of various parameters under normal workload and overload situation, the DDDP algorithm has improved the performance of scheduling obviously compared with a classical Earliest Deadline First (EDF) algorithm which only considers the deadlines of real-time tasks.
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Blind detection of image splicing based on image quality metrics and moment features
Zhen ZHANG Jiquan Kang Xijian Ping Yuan Ren
Journal of Computer Applications   
Abstract1761)      PDF (759KB)(1856)       Save
Image splicing is a technique commonly used in image tampering. To implement image splicing blind detection,a new splicing detection scheme was proposed. Image splicing detection could be regarded as a two-class pattern recognition problem and the model was established based on moment features and some Image Quality Metrics (IQMs) extracted from the given test image. This model could measure statistical differences between original image and spliced image. Kernel-based Support Vector Machine (SVM) was chosen as a classifier to train and test the given images. Experimental results demonstrate that this new splicing detection scheme has some advantages of high-accuracy and wide-application.
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