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  • Open Access


    GPR Wave Propagation Model in a Complex Geoelectric Structure Using Conformal First-Order Symplectic Euler Algorithm

    Man Yang1,2,3, Hongyuan Fang1,2,3,*, Juan Zhang4, Fuming Wang1,2,3, Jianwei Lei1,2,3, Heyang Jia1,2,3

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 793-816, 2019, DOI:10.32604/cmc.2019.06042

    Abstract Possessing advantages such as high computing efficiency and ease of programming, the Symplectic Euler algorithm can be applied to construct a ground-penetrating radar (GPR) wave propagation numerical model for complex geoelectric structures. However, the Symplectic Euler algorithm is still a difference algorithm, and for a complicated boundary, ladder grids are needed to perform an approximation process, which results in a certain amount of error. Further, grids that are too dense will seriously decrease computing efficiency. This paper proposes a conformal Symplectic Euler algorithm based on the conformal grid technique, amends the electric/magnetic field-updating equations of… More >

  • Open Access


    Task-Based Resource Allocation Bid in Edge Computing Micro Datacenter

    Yeting Guo1, Fang Liu2,*, Nong Xiao1, Zhengguo Chen1,3

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 777-792, 2019, DOI:10.32604/cmc.2019.06366

    Abstract Edge computing attracts online service providers (SP) to offload services to edge computing micro datacenters that are close to end users. Such offloads reduce packet-loss rates, delays and delay jitter when responding to service requests. Simultaneously, edge computing resource providers (RP) are concerned with maximizing incomes by allocating limited resources to SPs. Most works on this topic make a simplified assumption that each SP has a fixed demand; however, in reality, SPs themselves may have multiple task-offloading alternatives. Thus, their demands could be flexibly changed, which could support finer-grained allocations and further improve the incomes… More >

  • Open Access


    A Dynamic Memory Allocation Optimization Mechanism Based on Spark

    Suzhen Wang1, Shanshan Geng1, Zhanfeng Zhang1, Anshan Ye2, Keming Chen2, Zhaosheng Xu2, Huimin Luo2, Gangshan Wu3,*, Lina Xu4, Ning Cao5

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 739-757, 2019, DOI:10.32604/cmc.2019.06097

    Abstract Spark is a distributed data processing framework based on memory. Memory allocation is a focus question of Spark research. A good memory allocation scheme can effectively improve the efficiency of task execution and memory resource utilization of the Spark. Aiming at the memory allocation problem in the Spark2.x version, this paper optimizes the memory allocation strategy by analyzing the Spark memory model, the existing cache replacement algorithms and the memory allocation methods, which is on the basis of minimizing the storage area and allocating the execution area according to the demand. It mainly including two… More >

  • Open Access


    A New Anti-Quantum Proxy Blind Signature for Blockchain-Enabled Internet of Things

    Chaoyang Li1,2,3, Gang Xu2, Yuling Chen1,*, Haseeb Ahmad4, Jian Li3

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 711-726, 2019, DOI:10.32604/cmc.2019.06279

    Abstract Blockchain technology has become a research hotspot in recent years with the prominent characteristics as public, distributed and decentration. And blockchain-enabled internet of things (BIoT) has a tendency to make a revolutionary change for the internet of things (IoT) which requires distributed trustless consensus. However, the scalability and security issues become particularly important with the dramatically increasing number of IoT devices. Especially, with the development of quantum computing, many extant cryptographic algorithms applied in blockchain or BIoT systems are vulnerable to the quantum attacks. In this paper, an anti-quantum proxy blind signature scheme based on More >

  • Open Access


    The Topology Sampling of H2SO4·NH3 with Meta-Dynamics Method

    Yugai Huang1,2,3, Yu Shang1,4, Wenqing Li1, Jiajing He1, Hairong Zhou1, Bin Gu1,*

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 701-710, 2019, DOI:10.32604/cmc.2019.03109

    Abstract The configurations of molecular clusters have significant impacts on their growth into fine particles in atmosphere. In this paper, we explore the topology space of the structure of H2SO4·NH3 dimer with a novel sampling technique of meta-dynamics (MTD) method and ab initio molecular dynamics simulations. The simulations are carried out at the temperatures of both 50 K and 242 K, which represent the typical high and low latitudes of troposphere. The results show that, compared with only traditional MD simulations, the structure samplings are significantly accelerated with MTD method. Therefore, more isomers of the dimer More >

  • Open Access


    Cryptanalysis and Improvement of a Chaotic Map-Control-Based and the Plain Image-Related Cryptosystem

    Bin Lu1, Fenlin Liu1, Xin Ge1,*, Zhenyu Li2

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 687-699, 2019, DOI:10.32604/cmc.2019.05633

    Abstract Due to the characteristics of chaotic systems, different cryptosystems based on chaos have been proposed to satisfy the security of multimedia data. A plain image-related chaotic algorithm is proposed by Luo et al. with high speed and efficiency. Security weaknesses of the cryptosystem are studied in this paper. It is found that the important secret key information is leaked because an important parameter can be obtained after an inverse operation in the last step of the cryptosystems without secret key. Meanwhile, the value zero is processed improperly in quantification algorithm. Based on the weaknesses, chosen More >

  • Open Access


    Research on Architecture of Risk Assessment System Based on Block Chain

    Yang Zhao1, Shibin Zhang1,*, Min Yang1, Peilin He1, Qirun Wang2

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 677-686, 2019, DOI:10.32604/cmc.2019.05936

    Abstract The risk assessment system has been applied to the information security, energy, medical and other industries. Through the risk assessment system, it is possible to quantify the possibility of the impact or loss caused by an event before or after an event, thereby avoiding the risk or reducing the loss. However, the existing risk assessment system architecture is mostly a centralized architecture, which could lead to problems such as data leakage, tampering, and central cheating. Combined with the technology of block chain, which has the characteristics of decentralization, security and credibility, collective maintenance, and untamperability. More >

  • Open Access


    Novel DDoS Feature Representation Model Combining Deep Belief Network and Canonical Correlation Analysis

    Chen Zhang1, Jieren Cheng1,2,3,*, Xiangyan Tang1, Victor S. Sheng4, Zhe Dong1, Junqi Li1

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 657-675, 2019, DOI:10.32604/cmc.2019.06207

    Abstract Distributed denial of service (DDoS) attacks launch more and more frequently and are more destructive. Feature representation as an important part of DDoS defense technology directly affects the efficiency of defense. Most DDoS feature extraction methods cannot fully utilize the information of the original data, resulting in the extracted features losing useful features. In this paper, a DDoS feature representation method based on deep belief network (DBN) is proposed. We quantify the original data by the size of the network flows, the distribution of IP addresses and ports, and the diversity of packet sizes of More >

  • Open Access


    A New Time-Aware Collaborative Filtering Intelligent Recommendation System

    Weijin Jiang1,2,3, Jiahui Chen1,*, Yirong Jiang4,*, Yuhui Xu1, Yang Wang1, Lina Tan1, Guo Liang5

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 849-859, 2019, DOI:10.32604/cmc.2019.05932

    Abstract Aiming at the problem that the traditional collaborative filtering recommendation algorithm does not fully consider the influence of correlation between projects on recommendation accuracy, this paper introduces project attribute fuzzy matrix, measures the project relevance through fuzzy clustering method, and classifies all project attributes. Then, the weight of the project relevance is introduced in the user similarity calculation, so that the nearest neighbor search is more accurate. In the prediction scoring section, considering the change of user interest with time, it is proposed to use the time weighting function to improve the influence of the More >

  • Open Access


    An Efficient Quantum Key Distribution Protocol with Dense Coding on Single Photons

    Hao Xiao1,*, Jun Zhang2, Wenhua Huang3, Mi Zhou4, Wencheng Hu5

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 759-775, 2019, DOI:10.32604/cmc.2019.06085

    Abstract Combined with the dense coding mechanism and the bias-BB84 protocol, an efficient quantum key distribution protocol with dense coding on single photons (QDKD-SP) is proposed. Compared with the BB84 or bias-BB84 protocols based on single photons, our QDKD-SP protocol has a higher capacity without increasing the difficulty of its experiment implementation as each correlated photon can carry two bits of useful information. Compared with the quantum dense key distribution (QDKD) protocol based on entangled states, our protocol is more feasible as the preparation and the measurement of a single-photon quantum state is not difficult with More >

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