Jing Liu^1,5, Jingbing Li^1,*, Jieren Cheng¹, Jixin Ma², Naveed Sadiq³, Baoru Han⁴, Qiang Geng⁵, Yang Ai⁵

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 889-910, 2019, DOI:10.32604/cmc.2019.06034

Abstract In order to solve the problem of patient information security protection in medical images, whilst also taking into consideration the unchangeable particularity of medical images to the lesion area and the need for medical images themselves to be protected, a novel robust watermarking algorithm for encrypted medical images based on dual-tree complex wavelet transform and discrete cosine transform (DTCWT-DCT) and chaotic map is proposed in this paper. First, DTCWT-DCT transformation was performed on medical images, and dot product was per-formed in relation to the transformation matrix and logistic map. Inverse transformation was undertaken to obtain encrypted medical images. Then, in… More >

Lili Yan^1,*, Yan Chang¹, Shibin Zhang¹, Qirun Wang², Zhiwei Sheng¹, Yuhua Sun¹

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 877-887, 2019, DOI:10.32604/cmc.2019.06222

Abstract Quantum private comparison is an important topic in quantum cryptography. Recently, the idea of semi-quantumness has been often used in designing private comparison protocol, which allows some of the participants to remain classical. In this paper, we propose a semi quantum private comparison scheme based on Greenberge-Horne-Zeilinger (GHZ) class states, which allows two classical participants to compare the equality of their private secret with the help of a quantum third party (server). In the proposed protocol, server is semi-honest who will follow the protocol honestly, but he may try to learn additional information from the protocol execution. The classical participants’… More >

Xiaoying Chen^{1, 2, *}, Shijun Zhao², Xiaolei Wang², Xuejin Sun², Jing Feng², Nan Ye³

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 861-875, 2019, DOI:10.32604/cmc.2019.06230

Abstract It is important to extract texture feature from the ground-base cloud image for cloud type automatic detection. In this paper, a new method is presented to capture the contour edge, texture and geometric structure of cloud images by using Contourlet and the power spectrum analysis algorithm. More abundant texture information is extracted. Cloud images can be obtained a multiscale and multidirection decomposition. The coefficient matrix from Contourlet transform of ground nephogram is calculated. The energy, mean and variance characteristics calculated from coefficient matrix are composed of the feature information. The frequency information of the data series from the feature vector… More >

Haiqi Zhu¹, Fanzhi Meng^2,*, Seungmin Rho³, Mohan Li^4,*, Jianyu Wang¹, Shaohui Liu¹, Feng Jiang¹

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 829-847, 2019, DOI:10.32604/cmc.2019.06115

Abstract In real-world many internet-based service companies need to closely monitor large amounts of data in order to ensure stable operation of their business. However, anomaly detection for these data with various patterns and data quality has been a great challenge, especially without labels. In this paper, we adopt an anomaly detection algorithm based on Long Short-Term Memory (LSTM) Network in terms of reconstructing KPIs and predicting KPIs. They use the reconstruction error and prediction error respectively as the criteria for judging anomalies, and we test our method with real data from a company in the insurance industry and achieved good… More >

Longqing Zhang¹, Liping Bai^1,*, Xinwei Zhang², Yanghong Zhang², Lei Yang¹, Xiangdu Yan²

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 817-828, 2019, DOI:10.32604/cmc.2019.06062

Abstract The drawbacks of the traditional multi-hop structure of wireless sensor networks (WSNS) are susceptible to reflection, scattering and diffraction, serious attenuation of signal intensity and phase deviation due to various obstacles in cultivated land environment and mountains. In this paper, the wireless signal intensity is measured and curve fitting is done respectively in both open environment and obstacle-environment with both sending and receiving height of 0 m, 1 m, and 2 m. It is found out that packet loss probability is too high when an obstacle exists. In such a case, unmanned aerial vehicle (UAV) is introduced to activate terrestrial… More >

Man Yang^1,2,3, Hongyuan Fang^1,2,3,*, Juan Zhang⁴, Fuming Wang^1,2,3, Jianwei Lei^1,2,3, Heyang Jia^1,2,3

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 the Symplectic Euler algorithm by… More >

Yeting Guo¹, Fang Liu^2,*, Nong Xiao¹, Zhengguo Chen^1,3

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 for RPs. Here, we propose… More >

Suzhen Wang¹, Shanshan Geng¹, Zhanfeng Zhang¹, Anshan Ye², Keming Chen², Zhaosheng Xu², Huimin Luo², Gangshan Wu^3,*, 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 parts: cache replacement optimization and… More >

Chaoyang Li^1,2,3, Gang Xu², Yuling Chen^1,*, 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 the lattice cryptography has been… More >

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 >