Shuyu Li¹, Guozheng Zhang^{1, *}

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 223-241, 2020, DOI:10.32604/cmc.2020.07499

Abstract With the popularity of sensor-rich mobile devices, mobile crowdsensing (MCS) has emerged as an effective method for data collection and processing. However, MCS platform usually need workers’ precise locations for optimal task execution and collect sensing data from workers, which raises severe concerns of privacy leakage. Trying to preserve workers’ location and sensing data from the untrusted MCS platform, a differentially private data aggregation method based on worker partition and location obfuscation (DP-DAWL method) is proposed in the paper. DP-DAWL method firstly use an improved K-means algorithm to divide workers into groups and assign different privacy budget to the group… More >

Shuzhuang Zhang¹, Hao Luo¹, Zhigang Wu¹, Yanbin Sun^{2, *}, Yuhang Wang², Tingting Yuan³

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 213-222, 2020, DOI:10.32604/cmc.2020.07496

Abstract With the rapid increase of link speed and network throughput in recent years, much more attention has been paid to the work of obtaining statistics over speed traffic streams. It is a challenging problem to identify heavy hitters in high-speed and dynamically changing data streams with less memory and computational overhead with high measurement accuracy. In this paper, we combine Bloom Filter with exponential histogram to query streams in the sliding window so as to identify heavy hitters. This method is called EBF sketches. Our sketch structure allows for effective summarization of streams over time-based sliding windows with guaranteed probabilistic… More >

Yinghua Zhang^{1, 2}, Jian Liu^{1, *}, Yunfeng Peng¹, Yanfang Dong², Guozhong Sun², Hao Huang³, Changming Zhao^{4, 5}

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 197-212, 2020, DOI:10.32604/cmc.2020.07059

Abstract This paper proposes a hybrid spectrum accessing mechanism by using NOMA-based cooperative transmission and beam-forming technology. In this mechanism, the secondary user employs spectrum-sensing technology to detect the existence of the primary user. If the primary user does not exist, the secondary source user directly transmits data to the destination user. If the primary user exists, the secondary source user finds the optimal relay according to certain selection principle before transmitting data to the destination user through the chosen relay node. For the signal receiving stage, the secondary user takes use of beam-forming technology to receive the signal from both… More >

Ruohan Meng^{1, 2}, Qi Cui^{1, 2}, Zhili Zhou^{1, 2}, Chengsheng Yuan^{1, 2, 3}, Xingming Sun^{1, 2, *}

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 183-196, 2020, DOI:10.32604/cmc.2020.05317

Abstract Information hiding tends to hide secret information in image area where is rich texture or high frequency, so as to transmit secret information to the recipient without affecting the visual quality of the image and arousing suspicion. We take advantage of the complexity of the object texture and consider that under certain circumstances, the object texture is more complex than the background of the image, so the foreground object is more suitable for steganography than the background. On the basis of instance segmentation, such as Mask R-CNN, the proposed method hides secret information into each object's region by using the… More >

Xuefeng Xi¹, Victor S. Sheng^{1, 2, *}, Shuhui Yang³, Baochuan Fu¹, Zhiming Cui¹

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 163-181, 2020, DOI:10.32604/cmc.2020.06992

Abstract The pattern of thematic progression, reflecting the semantic relationships between contextual two sentences, is an important subject in discourse analysis. We introduce a new corpus of Chinese news discourses annotated with thematic progression information and explore some computational methods to automatically extracting the discourse structural features of simplified thematic progression pattern (STPP) between contextual sentences in a text. Furthermore, these features are used in a hybrid approach to a major discourse analysis task, Chinese coreference resolution. This novel approach is built up via heuristic sieves and a machine learning method that comprehensively utilizes both the top-down STPP features and the… More >

Jing Li¹, Yong Yang^{2, *}, Hongmei Ge¹, Li Zhao³, Ruxue Guo^{3, 4}

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 151-162, 2020, DOI:10.32604/cmc.2020.05649

Abstract Coal rock mass instability fracture may result in serious hazards to underground coal mining. Acoustic emissions (AE) stimulated by internal structure fracture should carry lots of favorable information about health condition of rock mass. AE as a sensitive non-destructive test method is gradually utilized to detect anomaly conditions of coal rock. This paper proposes an improved multi-resolution feature to extract AE waveform at different frequency resolutions using Coilflet Wavelet Transform method (CWT). It is further adopt an efficient Light Gradient Boosting Machine (LightGBM) by several cascaded sub weak classifier models to merge AE features at different views of frequency for… More >

Jieren Cheng^{1, 2}, Canting Cai^{1, *}, Xiangyan Tang¹, Victor S. Sheng³, Wei Guo¹, Mengyang Li¹

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 131-150, 2020, DOI:10.32604/cmc.2020.06175

Abstract Traditional distributed denial of service (DDoS) detection methods need a lot of computing resource, and many of them which are based on single element have high missing rate and false alarm rate. In order to solve the problems, this paper proposes a DDoS attack information fusion method based on CNN for multi-element data. Firstly, according to the distribution, concentration and high traffic abruptness of DDoS attacks, this paper defines six features which are respectively obtained from the elements of source IP address, destination IP address, source port, destination port, packet size and the number of IP packets. Then, we propose… More >

Jian Liu¹, Lei Wang¹, Changming Zhao^{2, 3, *}, Alan Yang⁴

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 119-130, 2020, DOI:10.32604/cmc.2020.06074

Abstract In this paper, we consider a three-hop relay system based on interference cancellation technique in Underlay cognitive radio (CR) network. Although underlay CR has been shown as a promising technique to better utilize the source of primary users (PUs), its secondary performance will be severely degraded. On one hand, by adapting the Underlay spectrum sharing pattern, secondary users (SUs) would observe the strict power constraints and be interfered by primary users. On the other hand, limited transmit power results in limited transmission range, which greatly degrade the secondary transmission capacity. To solve the problems above, we propose an interference cancellation… More >

Khelifi Naim^{1, *}, Benahmed Khelifa², Bounaama Fateh³

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 97-117, 2020, DOI:10.32604/cmc.2020.09391

Abstract In order to strengthen their security issues, electrical companies devote particular efforts to developing and enhancing their fraud detection techniques that cope with the information and communication technologies integration in smart grid fields. Having been treated earlier by several researchers, various detection schemes adapted from attack models that benefit from the smart grid topologies weaknesses, aiming primarily to the identification of suspicious incoming hazards. Wireless meshes have been extensively used in smart grid communication architectures due to their facility, lightness of conception and low cost installation; however, the communicated packets are still exposed to be intercepted maliciously in order either… More >

Praveena R^{1, *}

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 85-95, 2020, DOI:10.32604/cmc.2020.08629

Abstract Digital design of a digital signal processor involves accurate and high-speed mathematical computation units. DSP units are one of the most power consuming and memory occupying devices. Multipliers are the common building blocks in most of the DSP units which demands low power and area constraints in the field of portable biomedical devices. This research works attempts multiple power reduction technique to limit the power dissipation of the proposed LUT multiplier unit. A lookup table-based multiplier has the advantage of almost constant area requirement’s irrespective to the increase in bit size of multiplier. Clock gating is usually used to reduce… More >