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  • Open Access

    ARTICLE

    A Survey on Digital Image Copy-Move Forgery Localization Using Passive Techniques

    Weijin Tan1,*, Yunqing Wu1, Peng Wu1, Beijing Chen1,2

    Journal of New Media, Vol.1, No.1, pp. 11-25, 2019, DOI:10.32604/jnm.2019.06219

    Abstract Digital images can be tampered easily with simple image editing software tools. Therefore, image forensic investigation on the authenticity of digital images’ content is increasingly important. Copy-move is one of the most common types of image forgeries. Thus, an overview of the traditional and the recent copy-move forgery localization methods using passive techniques is presented in this paper. These methods are classified into three types: block-based methods, keypoint-based methods, and deep learning-based methods. In addition, the strengths and weaknesses of these methods are compared and analyzed in robustness and computational cost. Finally, further research directions More >

  • Open Access

    ARTICLE

    T Application of MES System in the Safety Management of Offshore Oil and Gas Fields

    Yong Chen1,*, Lei Cui1, Chong Wang2

    Journal of Quantum Computing, Vol.1, No.1, pp. 41-48, 2019, DOI:10.32604/jqc.2019.06283

    Abstract In order to solve the problem of data island in the safety management of offshore oil and gas fields, take full advantage of data for subsequent analysis and development, and support production safety management of oil and gas fields, the MES, which is maturely applied in manufacturing and downstream production of CNOOC (China National Offshore Oil Corporation), is introduced by the petroleum administration at the eastern South China sea. The system adopts the real-time database and relational database to collect the scattered structured data, such as evidence information of offshore oil and gas production facilities… More >

  • Open Access

    ARTICLE

    Impact Damage Identification for Composite Material Based on Transmissibility Function and OS-ELM Algorithm

    Yajie Sun1,2,*, Yanqing Yuan2, Qi Wang2, Sai Ji1,2, Lihua Wang3, Shaoen Wu4, Jie Chen2, Qin Zhang2

    Journal of Quantum Computing, Vol.1, No.1, pp. 1-8, 2019, DOI:10.32604/jqc.2019.05788

    Abstract A method is proposed based on the transmissibility function and the Online Sequence Extreme Learning Machine (OS-ELM) algorithm, which is applied to the impact damage of composite materials. First of all, the transmissibility functions of the undamaged signals and the damage signals at different points are calculated. Secondly, the difference between them is taken as the damage index. Finally, principal component analysis (PCA) is used to reduce the noise feature. And then, input to the online sequence limit learning neural network classification to identify damage and confirm the damage location. Taking the amplitude of the More >

  • Open Access

    ARTICLE

    A Fatigue Damage Model for FRP Composite Laminate Systems Based on Stiffness Reduction

    Ying Zhao1, Mohammad Noori1,2, Wael A. Altabey1,3,*, Ramin Ghiasi4, Zhishen Wu1

    Structural Durability & Health Monitoring, Vol.13, No.1, pp. 85-103, 2019, DOI:10.32604/sdhm.2019.04695

    Abstract This paper introduces a stiffness reduction based model developed by the authors to characterize accumulative fatigue damage in unidirectional plies and (0/θ/0) composite laminates in fiber reinforced polymer (FRP) composite laminates. The proposed damage detection model is developed based on a damage evolution mechanism, including crack initiation and crack damage progress in matrix, matrix-fiber interface and fibers. Research result demonstrates that the corresponding stiffness of unidirectional composite laminates is reduced as the number of loading cycles progresses. First, three common models in literatures are presented and compared. Tensile viscosity, Young’s modulus and ultimate tensile stress… More >

  • Open Access

    ARTICLE

    Multi-Mode Guided Waves Based Reference-Free Damage Diagnostic Imaging in Plates

    Jiaqi Zhang1, Kehai Liu2,*, Chang Gao1, Zhanjun Wu1, Yuebin Zheng1, Dongyue Gao3

    Structural Durability & Health Monitoring, Vol.13, No.1, pp. 41-59, 2019, DOI:10.32604/sdhm.2019.05142

    Abstract Probability-based diagnostic imaging (PDI) is one of the most well-known damage identification methods using guided waves. It is usually applied to diagnose damage in plates. The previous studies were dependent on the certain damage index (DI) which is always calculated from the guided wave signals. In conventional methods, DI is simply defined by comparing the real-time data with the baseline data as reference. However, the baseline signal is easily affected by varying environmental conditions of structures. In this paper, a reference-free diagnostic imaging method is developed to avoid the influence of environmental factors, such as… More >

  • Open Access

    REVIEW

    System Identification of Heritage Structures Through AVT and OMA: A Review

    Vinay Shimpi1, Madappa V. R. Sivasubramanian1,*, S. B. Singh2

    Structural Durability & Health Monitoring, Vol.13, No.1, pp. 1-40, 2019, DOI:10.32604/sdhm.2019.05951

    Abstract In this review article, the past investigations carried out on heritage structures using Ambient Vibration Test (AVT) and Operational Modal Analysis (OMA) for system identification (determination of dynamic properties like frequency, mode shape and damping ratios) and associated applications are summarized. A total of 68 major research studies on heritage structures around the world that are available in literature are surveyed for this purpose. At first, field investigations carried out on heritage structures prior to conducting AVT are explained in detail. Next, specifications of accelerometers, location of accelerometers and optimization of accelerometer networks have been More >

  • Open Access

    ARTICLE

    Experimental Study of Aqueous Humor Flow in a Transparent Anterior Segment Phantom by Using PIV Technique

    Wenjia Wang1, 2, Xiuqing Qian1, 2, Qi Li1, 2, Gong Zhang1, 2, Huangxuan Zhao1, 2, Tan Li1, 2, Yang Yu1, 2, Hongfang Song1, 2, *, Zhicheng Liu1, 2, *

    Molecular & Cellular Biomechanics, Vol.16, No.1, pp. 59-74, 2019, DOI:10.32604/mcb.2019.06393

    Abstract Pupillary block is considered as an important cause of primary angle-closure glaucoma (PACG). In order to investigate the effect of pupillary block on the hydrodynamics of aqueous humor (AH) in anterior chamber (AC) and potential risks, a 3D printed eye model was developed to mimic the AH flow driven by fluid generation, the differential pressure between AC and posterior chambers (PC) and pupillary block. Particle image velocimetry technology was applied to visualize flow distribution. The results demonstrated obvious differences in AH flow with and without pupillary block. Under the normal condition (without pupillary block), the… More >

  • Open Access

    ARTICLE

    A Review on Deep Learning Approaches to Image Classification and Object Segmentation

    Hao Wu1, Qi Liu2, 3, *, Xiaodong Liu4

    CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 575-597, 2019, DOI:10.32604/cmc.2019.03595

    Abstract Deep learning technology has brought great impetus to artificial intelligence, especially in the fields of image processing, pattern and object recognition in recent years. Present proposed artificial neural networks and optimization skills have effectively achieved large-scale deep learnt neural networks showing better performance with deeper depth and wider width of networks. With the efforts in the present deep learning approaches, factors, e.g., network structures, training methods and training data sets are playing critical roles in improving the performance of networks. In this paper, deep learning models in recent years are summarized and compared with detailed More >

  • Open Access

    ARTICLE

    An Application-Oriented Buffer Management Strategy in Opportunistic Networks

    Meihua Liu1, Xinchen Zhang2,*, Shuangkui Ge3, Xiaoli Chen1, Jianbin Wu2, Mao Tian1

    CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 559-574, 2019, DOI:10.32604/cmc.2019.04843

    Abstract In Opportunistic networks (ONs), buffer management is critical to improve the message exchanging efficiency due to the limited storage space and transmission bandwidth at the wireless edge. Current solutions make message scheduling and drop policy based on assumptions that messages can always been forwarded in a single contact, and all node pairs have the same contact rates. However, such ideal assumptions are invalid for realistic mobility traces of hand-held. Recent studies show that the single contact duration is limited and the mobility of nodes is heterogeneous in reality. In this paper, a buffer management strategy… More >

  • Open Access

    ARTICLE

    Directional Antenna Intelligent Coverage Method Based on Traversal Optimization Algorithm

    Jialuan He1,2, Zirui Xing2, Rong Hu2, Jing Qiu3,*, Shen Su3,*, Yuhan Chai3, Yue Wu4

    CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 527-544, 2019, DOI:10.32604/cmc.2019.05586

    Abstract Wireless broadband communication is widely used in maneuver command communications systems in many fields, such as military operations, counter-terrorism and disaster relief. How to reasonably formulate the directional antenna coverage strategy according to the mobile terminal dynamic distribution and guide the directional antenna dynamic coverage becomes a practical research topic. In many applications, a temporary wireless boardband base station is required to support wireless signal communications between many terminals from nearby vehicles and staffs. It is therefore important to efficiently set directional antenna while ensuring large enough coverage over dynamically distributed terminals. The wireless broadband More >

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