Zhuo Zhou¹, Jiaohua Qin^1,*, Xuyu Xiang¹, Yun Tan¹, Qiang Liu¹, Neal N. Xiong²

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 217-231, 2020, DOI:10.32604/cmc.2020.06431

Abstract Due to the slow processing speed of text topic clustering in stand-alone architecture under the background of big data, this paper takes news text as the research object and proposes LDA text topic clustering algorithm based on Spark big data platform. Since the TF-IDF (term frequency-inverse document frequency) algorithm under Spark is irreversible to word mapping, the mapped words indexes cannot be traced back to the original words. In this paper, an optimized method is proposed that TF-IDF under Spark to ensure the text words can be restored. Firstly, the text feature is extracted by the TF-IDF algorithm combined CountVectorizer… More >

Fangming Bi^{1, 2}, Xuanyi Fu^{1, 2}, Wei Chen^{1, 2, 3, *}, Weidong Fang⁴, Xuzhi Miao^{1, 2}, Biruk Assefa^{1, 5}

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 199-216, 2020, DOI:10.32604/cmc.2020.06258

Abstract Aiming at the defects of the traditional fire detection methods, which are caused by false positives and false negatives in large space buildings, a fire identification detection method based on video images is proposed. The algorithm first uses the hybrid Gaussian background modeling method and the RGB color model to perform fire prejudgment on the video image, which can eliminate most non-fire interferences. Secondly, the traditional regional growth algorithm is improved and the fire image segmentation effect is effectively improved. Then, based on the segmented image, the dynamic and static features of the fire flame are further analyzed and extracted… More >

Panpan Zhai^{1, 2}, Ping Xu^{1, 2, *}

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 179-197, 2020, DOI:10.32604/cmc.2020.06474

Abstract When a tunnel is excavated below the groundwater table, groundwater flows in through the excavated wall of the tunnel and seepage forces act on it. These forces significantly affect the ground reaction curve, which is defined as the relationship between the internal pressure and radial displacement of the tunnel wall. This study investigates analytical solutions for seepage forces acting on the lining of a circular tunnel under steady-state groundwater flow. Considering the tunnel’s construction or service period and boundary conditions, the direction of maximum principal stress changes, and the input stress of the Mohr-Coulomb criterion varies. The stress distribution and… More >

Shaowei Weng^{1, 2, *}, Yiyun Liu¹, Yunqing Shi³, Bo Ou⁴, Chunyu Zhang⁵, Cuiping Wang⁶

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 157-177, 2020, DOI:10.32604/cmc.2020.05681

Abstract This paper proposes a two-step general framework for reversible data hiding (RDH) schemes with controllable contrast enhancement. The first step aims at preserving visual perception as much as possible on the basis of achieving high embedding capacity (EC), while the second step is used for increasing image contrast. In the second step, some peak-pairs are utilized so that the histogram of pixel values is modified to perform histogram equalization (HE), which would lead to the image contrast enhancement. However, for HE, the utilization of some peak-pairs easily leads to over-enhanced image contrast when a large number of bits are embedded.… More >

Yabin Xu^{1, 2, *}, Xuyang Meng¹, Yangyang Li³, Xiaowei Xu^{4, *}

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 137-155, 2020, DOI:10.32604/cmc.2020.05825

Abstract In order to effectively detect the privacy that may be leaked through social networks and avoid unnecessary harm to users, this paper takes microblog as the research object to study the detection of privacy disclosure in social networks. First, we perform fast privacy leak detection on the currently published text based on the fastText model. In the case that the text to be published contains certain private information, we fully consider the aggregation effect of the private information leaked by different channels, and establish a convolution neural network model based on multi-dimensional features (MF-CNN) to detect privacy disclosure comprehensively and… More >

Weijin Jiang^{1, 2, 3}, Yang Wang^1,*, Yirong Jiang^4,*, Yuhui Xu¹, Jiahui Chen¹, Lina Tan¹, Guo Liang⁵

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 123-136, 2020, DOI:10.32604/cmc.2020.05933

Abstract In mobile cloud computing, trust is a very important parameter in mobile cloud computing security because data storage and data processing are performed remotely in the cloud. Aiming at the security and trust management of mobile agent system in mobile cloud computing environment, the Human Trust Mechanism (HTM) is used to study the subjective trust formation, trust propagation and trust evolution law, and the subjective trust dynamic management algorithm (MASTM) is proposed. Based on the interaction experience between the mobile agent and the execution host and the third-party recommendation information to collect the basic trust data, the public trust host… More >

Cong Xu^{1, 2}, Zhenqi Sun^{2, 3}, Qi Jia^{2, 3}, Dezheng Zhang^{2, 3}, Yonghong Xie^{2, 3,*}, Alan Yang⁴

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 113-122, 2020, DOI:10.32604/cmc.2020.05239

Abstract With the success of new speech-based human-computer interfaces, there is a great need for effective and friendly dialogue agents that can communicate with people naturally and continuously. However, the lack of personality and consistency is one of critical problems in neural dialogue systems. In this paper, we aim to generate consistent response with fixed profile and background information for building a realistic dialogue system. Based on the encoder-decoder model, we propose a retrieval mechanism to deliver natural and fluent response with proper information from a profile database. Moreover, in order to improve the efficiency of training the dataset related to… More >

Jinwei Wang^{1, *}, Yang Zhang¹

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 99-112, 2020, DOI:10.32604/cmc.2020.04373

Abstract In the paper, a convolutional neural network based on quaternion transformation is proposed to detect median filtering for color images. Compared with conventional convolutional neural network, color images can be processed in a holistic manner in the proposed scheme, which makes full use of the correlation between RGB channels. And due to the use of convolutional neural network, it can effectively avoid the one-sidedness of artificial features. Experimental results have shown the scheme’s improvement over the state-of-the-art scheme on the accuracy of color image median filtering detection. More >

Dimitra Papagianni^{1, 2}, Magd Abdel Wahab^{3, 4, *}

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 79-97, 2020, DOI:10.32604/cmc.2020.07988

Abstract This paper deals with modeling of the phenomenon of fretting fatigue in heterogeneous materials using the multi-scale computational homogenization technique and finite element analysis (FEA). The heterogeneous material for the specimens consists of a single hole model (25% void/cell, 16% void/cell and 10% void/cell) and a four-hole model (25% void/cell). Using a representative volume element (RVE), we try to produce the equivalent homogenized properties and work on a homogeneous specimen for the study of fretting fatigue. Next, the fretting fatigue contact problem is performed for 3 new cases of models that consist of a homogeneous and a heterogeneous part (single… More >

Muhammad Shoaib Arif^{1, *}, Ali Raza¹, Muhammad Rafiq², Mairaj Bibi³, Javeria Nawaz Abbasi³, Amna Nazeer³, Umer Javed⁴

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 61-77, 2020, DOI:10.32604/cmc.2020.08595

Abstract We are presenting the numerical simulations for the stochastic computer virus propagation model in this manuscript. We are comparing the solutions of stochastic and deterministic computer virus models. Outcomes of a threshold number R₀ hold in stochastic computer virus model. If R₀ < 1 then in such a condition virus controlled in the computer population while R₀ > 1 shows virus rapidly spread in the computer population. Unfortunately, stochastic numerical techniques fail to cope with large step sizes of time. The suggested structure of the stochastic non-standard finite difference technique can never violate the dynamical properties. On this basis, we… More >