Yugai Huang^1,2,3, Yu Shang^1,4, Wenqing Li¹, Jiajing He¹, Hairong Zhou¹, Bin Gu^1,*

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 are discovered within the same… More >

Bin Lu¹, Fenlin Liu¹, Xin Ge^1,*, 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 plaintext attack on the cryptosystem… More >

Yang Zhao¹, Shibin Zhang^1,*, 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. This paper proposes a new… More >

Chen Zhang¹, Jieren Cheng^1,2,3,*, 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 different protocols and train the… More >

Weijin Jiang^1,2,3, Jiahui Chen^1,*, Yirong Jiang^4,*, 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 time effect of the evaluation,… More >

Hao Xiao^1,*, 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 current technology. In addition, our… More >

Yong Ding¹, Lei Tian¹, Bo Han², Huiyong Wang^2,*, Yujue Wang¹, James Xi Zheng³

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 727-738, 2019, DOI:10.32604/cmc.2019.06220

Abstract Currently, many biometric systems maintain the user’s biometrics and templates in plaintext format, which brings great privacy risk to uses’ biometric information. Biometrics are unique and almost unchangeable, which means it is a great concern for users on whether their biometric information would be leaked. To address this issue, this paper proposes a confidential comparison algorithm for iris feature vectors with masks, and develops a privacy-preserving iris verification scheme based on the El Gamal encryption scheme. In our scheme, the multiplicative homomorphism of encrypted features is used to compare of iris features and their mask information. Also, this paper improves… More >

Feng Li^1,2, Chaofeng Ou², Yan Gui^1,2,3,*, Lingyun Xiang^1,2

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 643-656, 2019, DOI:10.32604/cmc.2019.06094

Abstract The ability to quickly and intuitively edit digital content has become increasingly important in our everyday life. However, existing edit propagation methods for editing digital images are typically based on optimization with high computational cost for large inputs. Moreover, existing edit propagation methods are generally inefficient and highly time-consuming. Accordingly, to improve edit efficiency, this paper proposes a novel edit propagation method using a bilateral grid, which can achieve instant propagation of sparse image edits. Firstly, given an input image with user interactions, we resample each of its pixels into a regularly sampled bilateral grid, which facilitates efficient mapping from… More >

Tiantian Tan^1,*, Baosheng Wang¹, Yong Tang¹, Xu Zhou¹, Jingwen Han²

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 629-641, 2019, DOI:10.32604/cmc.2019.06049

Abstract Vulnerability technology is the basic of network security technology, vulnerability quantitative grading methods, such as CVSS, WIVSS, ICVSS, provide a reference to vulnerability management, but the problems of ignoring the risk elevation caused by a group of vulnerabilities and low accuracy of exploitable level evaluation exist in current vulnerability quantitative grading methods. To solve problems above in current network security quantitative evaluation methods, this paper verified the high relevance degree between type and exploitable score of vulnerability, proposed a new vulnerability quantitative grading method ICVSS, ICVSS can explore attack path using continuity level defined by privilege, add vulnerability type to… More >

Tianci Xia^1,2, Yuan Sun^1,2,*, Xiaobing Zhao^1,2, Wei Song¹, Yumiao Guo³

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 617-628, 2019, DOI:10.32604/cmc.2019.05860

Abstract With the emergence of large-scale knowledge base, how to use triple information to generate natural questions is a key technology in question answering systems. The traditional way of generating questions require a lot of manual intervention and produce lots of noise. To solve these problems, we propose a joint model based on semi-automated model and End-to-End neural network to automatically generate questions. The semi-automated model can generate question templates and real questions combining the knowledge base and center graph. The End-to-End neural network directly sends the knowledge base and real questions to BiLSTM network. Meanwhile, the attention mechanism is utilized… More >