Current Issue : July - September Volume : 2019 Issue Number : 3 Articles : 5 Articles
Broadcasting is a fundamental function for disseminating messages in multihop wireless networks. Minimum-Transmission\nBroadcasting (MTB) problem aims to find a broadcast schedule with minimum number of transmissions. Previous works on\nMTB in duty-cycled networks exploit a rigid assumption that nodes have only active time slot per working cycle. In this paper,\nwe investigated the MTB problem in duty-cycled networks where nodes are allowed arbitrary active time slots per working cycle\n(MTBDCA problem). Firstly, it is proved to be NP-hard.........
The resolvent is a fundamental concept in studying various operator splitting algorithms.\nIn this paper, we investigate the problem of computing the resolvent of compositions of operators\nwith bounded linear operators. First, we discuss several explicit solutions of this resolvent operator\nby taking into account additional constraints on the linear operator. Second, we propose a fixed point\napproach for computing this resolvent operator in a general case. Based on the Krasnoselskiiâ??Mann\nalgorithm for finding fixed points of non-expansive operators, we prove the strong convergence of\nthe sequence generated by the proposed algorithm. As a consequence, we obtain an effective iterative\nalgorithm for solving the scaled proximity operator of a convex function composed by a linear\noperator, which has wide applications in image restoration and image reconstruction problems.\nFurthermore, we propose and study iterative algorithms for studying the resolvent operator of a finite\nsum of maximally monotone operators as well as the proximal operator of a finite sum of proper,\nlower semi-continuous convex functions....
Malicious domain name attacks have become a serious issue for Internet security. In this study, a malicious domain names\ndetection algorithm based on N-Gram is proposed. The top 100,000 domain names in Alexa 2013 are used in the N-Gram method.\nEach domain name excluding the top-level domain is segmented into substrings according to its domain level with the lengths of\n3, 4, 5, 6, and 7. The substring set of the 100,000 domain names is established, and the weight value of a substring is calculated\naccording to its occurrence number in the substring set. To detect a malicious attack, the domain name is also segmented by the NGram\nmethod and its reputation value is calculated based on the weight values of its substrings. Finally, the judgment of whether\nthe domain name is malicious is made by thresholding. In the experiments on Alexa 2017 and Malware domain list, the proposed\ndetection algorithm yielded an accuracy rate of 94.04%, a false negative rate of 7.42%, and a false positive rate of 6.14%. The time\ncomplexity is lower than other popular malicious domain names detection algorithms....
Biases of initial direction estimation and focusing frequency selection affect the final\nfocusing effect and may even cause algorithm failure in determining the focusing matrix in the\ncoherent signalâ??subspace method. An optimized sonar broadband focused beamforming algorithm\nis proposed to address these defects. Initially, the robust Capon beamforming algorithm was used\nto correct the focusing matrix, and the broadband signals were then focused on the optimal focusing\nfrequency by the corrected focusing matrix such that the wideband beamforming was transformed\ninto a narrowband problem. Finally, the focused narrowband signals were beamformed by the\nsecond-order cone programming algorithm. Computer simulation results and water pool\nexperiments verified that the proposed algorithm provides a good performance....
Due to the dynamic change of the opportunistic network topology and the lack of stable\ninformation transmission paths between nodes, the traditional topology-based routing algorithm\ncannot achieve the desired routing performance. To address of this problem, this paper proposes a\nrouting algorithm based on trajectory prediction (RATP). The routing protocol based on trajectory\nprediction can efficiently and quickly adapt to the network link quality instability and the dynamic\nchanges of network topology. RATP algorithm constructs a node mobility model by analyzing the\nhistorical mobility characteristics of the nodes. According to the node prediction information, the\nmetric value of the candidate node is calculated, and the node with the smaller metric value is\nselected as the data forwarding node, which can effectively reduce the packet loss rate and avoids\nexcessive consumption. Simulation results show that compared with other algorithms, the proposed\nalgorithm has higher data delivery ratio, and end-to-end data delay and routing overhead are\nsignificantly reduced....
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