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    Task scheduling algorithm based on improved genetic algorithm in cloud computing environment
    Journal of Computer Applications    2011, 31 (01): 184-186.  
    Abstract2725)      PDF (435KB)(85870)       Save
    The number of user is huge in Cloud Computing, and the number of tasks and the amount of data are also huge. How to schedule tasks efficiently is an important issue to be resolved in Cloud Computing environment. An Double-Fitness Genetic Algorithm (DFGA) is brought up for the programming framework of Cloud Computing. Through this algorithm the better task scheduling result which has not only shorter total-task-completion time and also has shorter average-completion time can be found out. There is a contrast between DFGA and Adaptive Genetic Algorithm (AGA) through simulation experiment, and the result is: the DFGA is better, it is an efficiently task scheduling algorithm in Cloud Computing environment.
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    Use of RFID technology for indoor location
    Journal of Computer Applications   
    Abstract1844)      PDF (638KB)(53583)       Save
    Radio Frequency IDentification (RFID) Technology and its different applications in various sectors, particularly, in the indoor location, were briefly introduced. The theory of LANDMARC indoor location system was improved to make it more realistic in use. The experimental results show that the improved algorithm yields an accuracy of 10%~50% higher than the original one does.
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    Stateless communication mechanism between an IPv4 network and the IPv6 Internet
    HAN Guoliang, SHENG Maojia, BAO Congxiao, LI Xing
    Journal of Computer Applications    2015, 35 (8): 2113-2117.   DOI: 10.11772/j.issn.1001-9081.2015.08.2113
    Abstract925)      PDF (938KB)(49100)       Save

    In the IPv4/IPv6 transition process, since some legacy IPv4 networks still need to communicate with the IPv6 Internet, the stateless communication mechanism between an IPv4 network and the IPv6 Internet, which complements the current IPv4/IPv6 translation framework, was proposed. First, the communication procedures in two related scenarios were demonstrated. The two scenarios include IPv6 Internet clients accessing IPv4 servers and IPv4 clients accessing IPv6 Internet servers. The one-way IPv6-IPv4 address mapping function is the key component of the mechanism. Therefore, the requirements and three quantitative criteria of the one-way mapping function were discussed. Afterwards, multiple Hash functions as the candidates of the one-way mapping function were compared and analyzed with the real user data of large IPv6 websites and real IPv6 server addresses. The simulation results show that the FarmCity Hash function is suitable to be deployed in the above two scenarios because it has short average processing time, low collision rate and low reverse query complexity. It also verifies the validity of the stateless communication mechanism. Compared with current stateful communication mechanisms, the stateless mechanism has better scalability and traceability. Moreover, the capacity for bidirectional communication facilitates a smooth migration path towards the IPv6 Internet.

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    Cloud computing and its key techniques
    Journal of Computer Applications    2009, 29 (09): 2562-2567.  
    Abstract4289)      PDF (931KB)(48527)       Save
    Cloud computing is a new computing model; it is developed based on grid computing. The authors introduced the development history of cloud computing and its application situation; compared existing definitions of cloud computing and gave a new definition; took google's cloud computing techniques as an example, summed up key techniques, such as data storage technology (Google File System), data management technology (BigTable), as well as programming model and task scheduling model(Map-Reduce), used in cloud computing; and analyzed the differences among cloud computing, grid computing and traditional super-computing, and fingered out the broad development prospects of cloud computing.
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    Parallelization design of face recognition algorithm based on Matlab multi-core clusters
    ZHENG Xiao-wei YU Meng-ling
    Journal of Computer Applications    2011, 31 (10): 2597-2599.   DOI: 10.3724/SP.J.1087.2011.02597
    Abstract1461)      PDF (485KB)(45886)       Save
    In order to take full advantage of multi-core processor resources, the parallel programming model by building blocks with multithreading was studied, hence improving the performance of the program. According to the integral structure of Principal Component Analysis (PCA)-based face recognition algorithm, a functional module named train() was designed for the training of recognizing generated samples in the environment of Matlab cluster. The parallelization of this algorithm was realized by task partition. The experimental results indicate that the stable recognition rate of 94.167% and the approximately linear speed-up ratio verify the correctness and high efficiency of the parallel algorithm.
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    Joint switch scheduling and resource allocation algorithm based on energy efficiency in heterogeneous wireless networks
    QIU Changxiao, LENG Supeng, YE Yu
    Journal of Computer Applications    2015, 35 (6): 1505-1508.   DOI: 10.11772/j.issn.1001-9081.2015.06.1505
    Abstract630)      PDF (787KB)(39071)       Save

    In order to improve the energy efficiency of the heterogeneous wireless networks with macro-cells and micro-cells, a Joint Switch scheduling and Resource Allocation (JSRA) algorithm was proposed. Firstly, based on sleeping of micro base stations, Centralized User Switch scheduling Algorithm (CUSA) was adopted to determine the associated base station for each user. The sleeping/waking status of a micro base station was judged according to whether to decrease of network power consumption when users of the micro base station entirely switched to macro base station.Then, the Best Channel quality Subcarrier Adjustment (BCSA) algorithm was used to assign subcarriers and transmission power for users. The network energy efficiency was guaranteed to approximate the optimal solution by adjusting the subcarrier allocation between the user with the maximum energy efficiency and the user with the minimum energy efficiency. The theoretical analysis and simulation experiments show that,compared with three existing algorithms which considered user handoff or resource allocation separately, JSRA has high computational complexity; however, when the number of users is 120, JSRA can reduce network power consumption 44.4% at most, increase the total effective data rate of users by 80% with the slight reduction only than one contrast as well as the energy efficiency of the network by 200% at most. Experimental results show JSRA can improve the energy efficiency of heterogeneous wireless networks effectively.

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    Cooperative spectrum sharing method based on spectrum contract
    ZHAO Nan, WU Minghu, ZHOU Xianjun, XIONG Wei, ZENG Chunyan
    Journal of Computer Applications    2015, 35 (7): 1805-1808.   DOI: 10.11772/j.issn.1001-9081.2015.07.1805
    Abstract569)      PDF (749KB)(38226)       Save

    To alleviate the shortage of licensed spectrum resource, a method to design and implement the multi-user Cooperative Spectrum Sharing (CSS) mechanism was proposed based on the characteristics of asymmetric network information and selfishness of communication users. First, by modeling the CSS as a labor market, a modeling method for the multi-user contract-based CSS framework was investigated under the symmetric network information scenario. Then, to avoid the moral hazard problem due to the hidden-action of Secondary Users (SUs) after contract assignment, a contract-based CSS model was proposed to incentivize the contribution of SUs for ensuring spectrum sharing. The experimental results show that, when the direct transmission rate of Primary User (PU) is less than 0.2 b/s, in comparison with the case of non-cooperative spectrum sharing, the capacity of network is more than 3 times larger. The proposed multi-user contract-based CSS framework will put forward new ideas for efficient sharing and utilization of spectrum resource.

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    Unsupervised deep learning method for color image recognition
    KANG Xiaodong, WANG Hao, GUO Jun, YU Wenyong
    Journal of Computer Applications    2015, 35 (9): 2636-2639.   DOI: 10.11772/j.issn.1001-9081.2015.09.2636
    Abstract1156)      PDF (578KB)(38113)       Save
    In view of significance of color image recognition, the method of color image recognition based on data of image features and Deep Belief Network (DBN) was presented. Firstly, data field of color image was constructed in accord with human visual characteristics; secondly, wavelet transforms was applied to describe multi-scale feature of image; finally, image recognition could be made by training unsupervised DBN.The experimental results show that compared with the methods of Adaboost and Support Vector Machine(SVM),classification accuracy is improved by 3.7% and 2.8% respectively and better image recognition is achieved by the proposed method.
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    Hybrid detection technique for Android kernel hook
    HUA Baojian ZHOU Aiting ZHU Hongjun
    Journal of Computer Applications    2014, 34 (11): 3336-3339.   DOI: 10.11772/j.issn.1001-9081.2014.11.3336
    Abstract620)      PDF (820KB)(29768)       Save

    To address the challenge of Android kernel hook detection, a new approach was proposed to detect Android kernel hooks by combining static technique based on characteristic pattern and dynamic technique based on behavioural analysis. The attacks including modifying system call tables and inline hook could be detected by the proposed approach. Software prototypes and test experiments were given. The experimental results show that the proposed method is effective and efficient in detecting Android kernel hooks, for most of the test cases, the runtime overhead is below 7%; and it is suitable to detect Android kernel hooks.

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    Message generation and store model based on HL7V2.x protocol
    FAN Xiao HUANG Qing-song
    Journal of Computer Applications    2011, 31 (12): 3418-3421.  
    Abstract1391)      PDF (561KB)(29351)       Save
    Data can not be communicated so well according to the unified data standards among the health information systems in our country that information sharing is impeded. On the basis of the HL7 V2.x (health level seven Version2.x) protocol of health information communication standard and the theory of HL7V2.x message parsing, the method in which data in the database fields is extracted to generate HL7V2.x messages and parsed message information is stored in the specific database is introduced in detail. Then an optimized model of the message store and the message generation is brought forward. In this model, mapping files are designed to save much time in redundant manual configurations and the hash table is used as a data structure during the process of message generation to make it more efficient. Simulation experiment results show the feasibility of the model.
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    Enhanced frequency-domain channel contention mechanism in wireless local area network
    WANG Jing, GAO Zehua, GAO Feng, PAN Xiang
    Journal of Computer Applications    2015, 35 (2): 317-321.   DOI: 10.11772/j.issn.1001-9081.2015.02.0317
    Abstract828)      PDF (718KB)(28852)       Save

    Concerning the high overheads of current channel access mechanisms and frequent collisions in high-density deployed Wireless Local Area Network (WLAN), an enhanced mechanism named as Hybrid Frequency-domain Channel Contention (HFCC) based on frequency-domain channel contention was proposed. Firstly, the subcarriers within Orthogonal Frequency Division Multiplexing (OFDM) symbols which were used for frequency-domain channel contention were classified as contention subcarriers and information subcarriers. Secondly, two rounds of channel contention were performed when station (STA) needs to access channel and the confirmation of successful channel contention was performed if necessary. Finally, a single OFDM symbol was used to acknowledge correct reception of a packet. The theoretical analysis showed that, compared with Distributed Coordination Function (DCF), when many STAs (35 or so) were contending a channel in the network, the collision probability of HFCC declined 99.1%, and the system throughput of it increased 73.2%. In addition, the throughput of HFCC respectively increased by 35.7% and 75.2% compared with Back2F and REPICK. The analysis results show that HFCC can reduce the overhead while improving the robustness, which is suitable for high-density deployed network.

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    Research and simulation of radar side-lobe suppression based on Kalman-minimum mean-square error
    ZHANG Zhaoxia, WANG Huihui, FU Zheng, YANG Lingzhen, WANG Juanfen, LIU Xianglian
    Journal of Computer Applications    2015, 35 (5): 1488-1491.   DOI: 10.11772/j.issn.1001-9081.2015.05.1488
    Abstract559)      PDF (608KB)(28467)       Save

    Concerning the problem that the weak target might be covered by the range side-lobes of the strong one and the range side-lobes could only be suppressed to a certain value, an improved Kalman-Minimum Mean-Square Error (K-MMSE) algorithm was proposed in this paper. This algorithm combined the Kalman filter with the Minimum Mean-Square Error (MMSE), and it was an effective method for suppressing range side-lobes of adaptive pulse compression. In the simulation, the proposed algorithm was compared with the traditional matched filter and other improved matched filters such as MMSE in a single target or multiple targets environments, and then found that the side-lobe levels, the Peak-SideLobe Ratio (PSLR) and Integrated SideLobe Ratio (ISLR) of the Point Spread Function (PSF) were all decreased obviously in comparison with the previous two methods. The simulation results show that the method can suppress range side-lobes well and detect the weak targets well either under both the condition of a single target and the condition of multiple targets.

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    Optimization between multiple input multiple output radar signal and target interference based on Stackelberg game
    LAN Xing, WANG Xingliang, LI Wei, WU Haotian, JIANG Mengran
    Journal of Computer Applications    2015, 35 (4): 1185-1189.   DOI: 10.11772/j.issn.1001-9081.2015.04.1185
    Abstract516)      PDF (677KB)(27392)       Save

    To solve the problem of the game of detection and stealth in the presence of clutter between Multiple Input Multiple Output (MIMO) radar and target, a new two-step water-filling was proposed. Firstly, space-time coding model was built. Then based on mutual information, water-filling was applied to distribute target interference power, and generalized water-filling was applied to distribute radar signal power. Lastly, optimization schemes in Stackelberg game of target dominant and radar dominant were achieved under strong and weak clutter. The simulation results indicate that both radar signal power allocation and trend of generalized water-filling level are affected by clutter, therefore two optimization schemes' mutual information in strong clutter environment is about half and interference factor decreases 0.2 and 0.25 separately, mutual information is less sensitive to interference. The availability of the proposed algorithm is proved.

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    Improved beer bottles recognition technology
    Feng FU Duan WANG
    Journal of Computer Applications   
    Abstract1498)      PDF (492KB)(25452)       Save
    Beer bottles recognition is an important step in whole beers intelligent system. This paper presented a recognition system based on wavelet moment and Support Vector Machine (SVM). The experimental results show that the method has a good recognition rate and less loss-time, which satisfies the industrial need.
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    Delay-aware algorithm of cross-layer design for device-to-device communication based on max-weighted queue
    YU Shengsheng, GE Wancheng, GUO Aihuang
    Journal of Computer Applications    2015, 35 (5): 1205-1208.   DOI: 10.11772/j.issn.1001-9081.2015.05.1205
    Abstract631)      PDF (564KB)(24683)       Save

    Max Weighted Queue (MWQ) control policy based on the theory of Lyapunov optimization is a cross-layer control policy that achieves queue stability and optimal delay performance. For the real-time and delay-sensitive demand in Device-to-Device (D2D) communication services, the MWQ algorithm, in which the Channel State Information (CSI) of PHY layer and the Queue State Information (QSI) of MAC layer are collectively considered, makes the maximum system throughput as the objective function and controls the power of D2D nodes dynamic. In this paper, a novel MWQ algorithm in the D2D communication was proposed. Compared to the algorithm with fixed power, the CSI-based algorithm and the QSI-based algorithm, the MWQ algorithm can decrease the average delay about 0.5 s when the average packets arrival rate exceeds 10 Mb/s and require less 26 dB power while having the same average delay. So the MWQ algorithm can achieve a good performance and have a reference to obtain low latency in D2D communication.

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    Flower pollination algorithm based on simulated annealing
    XIAO Huihui, WAN Changxuan, DUAN Yanming, ZHONG Qing
    Journal of Computer Applications    2015, 35 (4): 1062-1066.   DOI: 10.11772/j.issn.1001-9081.2015.04.1062
    Abstract864)      PDF (799KB)(24540)       Save

    A hybrid algorithm of Simulated Annealing (SA) and flower pollination algorithm was presented to overcome the problems of low-accuracy computation, slow-speed convergence and being easily relapsed into local extremum. The sudden jump strategy in SA was utilized to avoid falling into local optimum, and the global searching performance of SA was exploited to enhance the global searching ability of the hybrid algorithm. The hybrid algorithm was tested through six standard functions and compared to basic Flower Pollination Algorithm (FPA), Bat Algorithm (BA), Particle Swarm Optimization (PSO) algorithm and improved PSO algorithm. The simulation results show that the optimal value of 4 functions were found by the hybrid algorithm with better convergence precision, convergence rate and robustness. At the same time, the experimental results of solving nonlinear equation group verify the validity of the hybrid algorithm.

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    Ear recognition based on improved 2D principal component analysis and neural network
    Journal of Computer Applications    2009, 29 (12): 3357-3359.  
    Abstract1754)      PDF (447KB)(24465)       Save
    Since the human ear feature extraction method of 2 Dimensional Principal Component Analysis (2DPCA) gets relatively bigger features dimension, which leads to poor real-time capability and lack of data storage space, the authors proposed a new approach. First of all, pretreatment of human ear pictures was completed. Then an improved 2DPCA algorithm was used to compress feature dimension. Finally, BP neural network was used in ear classification. Experimental results show that this method is of real-time and can save feature data storage space, and also maintains the recognition rate.
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    Research and application of vertical search engine in networked manufacturing resource〖JP〗
    Journal of Computer Applications   
    Abstract2375)      PDF (539KB)(23389)       Save
    This paper put emphasis on the technologies of the system, including the topic crawler and the Chinese word segmentation. To improve the efficiency of the crawler, a model of page evaluation was added into the crawler module; therefore the urls in a page with a high similarity of the topic will be first crawled. Besides, an improved word matching algorithm was proposed to enhance the speed and precision of word segmentation.
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    Spectrum allocation based on immune multi-objective optimization in cognitive mesh networks
    LI Yalun YANG Yanan CAI Zhengyi
    Journal of Computer Applications    2014, 34 (8): 2239-2242.   DOI: 10.11772/j.issn.1001-9081.2014.08.2239
    Abstract256)      PDF (588KB)(23269)       Save

    To study spectrum allocation problem in Cognitive Wireless Mesh Network (CWMN), an immune-based multi-objective optimization algorithm was proposed. The problem was modeled as a multi-objective optimization problem to maximize total bandwidth and minimize the total number of occupied spectra. Antibody encoding, whole cloning operator and non-dominated anti-body selection operator that are suitable for solving the problem were designed. The simulations results show that the proposed algorithm can obtain the Pareto optimal solutions of CWMN spectrum allocation, which improves the total bandwidth and minimizes the occupied spectra, so it optimizes the spectrum allocation performance.

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    Secret sharing scheme only needing XOR operations
    YUAN Qizhao, CAI Hongliang, ZHANG Jingzhong, XIA Hangyu
    Journal of Computer Applications    2015, 35 (7): 1877-1881.   DOI: 10.11772/j.issn.1001-9081.2015.07.1877
    Abstract536)      PDF (925KB)(22895)       Save

    The traditional secret sharing schemes based on interpolation polynomial require a heavy computational cost. When the data is large, the efficiency of operation is particularly low. Therefore, a new secret sharing scheme for protecting the security of large scale data was proposed. The proposed scheme used the data block's method and need the exclusive-OR (XOR) operation over GF(2) only. The theoretical analysis and experimental results show that, compared to the traditional secret sharing scheme based on interpolation polynomial, the new scheme is increased by 19.3% in the operational efficiency.

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    Rapid convergence algorithms for weight values updating based on BP network
    Journal of Computer Applications   
    Abstract2000)      PDF (567KB)(22717)       Save
    To solve the slow convergence of standard learning algorithm in BP network,two rapid convergence algorithms were suggested for weight values updating. One is rapid transmission algorithm based on gradient change rate. The other is flexible transmission algorithm based on gradient orientation. The two algorithms were simulated and compared in Game Style Training System for Mine Accident Rescuing. Here the algorithms would help game roles learn to estimate the danger degree according to ingredients of mine air, and then help trainees or biorobots take corresponding actions. The simulating results show that shorter convergence time is taken for the two algorithms than the standard algorithm.
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