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  • Open Access

    ARTICLE

    Modeling Rogowski Coils for Monitoring Surge Arrester Discharge Currents

    Nehmdoh A. Sabiha1,*, Hend I. Alkhammash2

    Computer Systems Science and Engineering, Vol.42, No.2, pp. 439-449, 2022, DOI:10.32604/csse.2022.022506 - 04 January 2022

    Abstract Rogowski coils (RCs) are widely used to measure power or high frequency currents based on their design. In this paper, two types of RCs that are circular (traditional) and cylindrical shapes wound using wire covered by varnish are constructed. This construction is carried out to be suitable for monitoring the discharge current of the surge arrester installed in the distribution system. Concerning high frequency RC modeling for both types considering transfer function is introduced. Self-integrating for both types is attained. Therefore, the experimental tests using function generator for both coils are carried out to identify… More >

  • Open Access

    ARTICLE

    A Fast Approach for Predicting Aerodynamic Noise Sources of High-Speed Train Running in Tunnel

    Deng Qin1, Tian Li1,*, Honglin Wang2, Jizhong Yang3, Yao Jiang3, Jiye Zhang1, Haiquan Bi2

    CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.3, pp. 1371-1386, 2022, DOI:10.32604/cmes.2022.018480 - 30 December 2021

    Abstract The aerodynamic noise of high-speed trains passing through a tunnel has gradually become an important issue. Numerical approaches for predicting the aerodynamic noise sources of high-speed trains running in tunnels are the key to alleviating aerodynamic noise issues. In this paper, two typical numerical methods are used to calculate the aerodynamic noise of high-speed trains. These are the static method combined with non-reflective boundary conditions and the dynamic mesh method combined with adaptive mesh. The fluctuating pressure, flow field and aerodynamic noise source are numerically simulated using the above methods. The results show that the More >

  • Open Access

    ARTICLE

    Numerical Investigation on the Aerodynamic Noise Generated by a Simplified Double-Strip Pantograph

    Jiawei Shi1, Shuai Ge1, Xiaozhen Sheng2,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 463-480, 2022, DOI:10.32604/fdmp.2022.017508 - 16 December 2021

    Abstract In order to understand the mechanism by which a pantograph can generate aerodynamic noise and grasp its far-field characteristics, a simplified double-strip pantograph is analyzed numerically. Firstly, the unsteady flow field around the pantograph is simulated in the frame of a large eddy simulation (LES) technique. Then the location of the main noise source is determined using surface fluctuating pressure data and the vortex structures in the pantograph flow field are analyzed by means of the Q-criterion. Based on this, the relationship between the wake vortex and the intensity of the aerodynamic sound source on… More >

  • Open Access

    ARTICLE

    A Chopper Negative-R Delta-Sigma ADC for Audio MEMS Sensors

    Jamel Nebhen1,*, Pietro M. Ferreira2,3

    CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.2, pp. 607-631, 2022, DOI:10.32604/cmes.2022.016086 - 13 December 2021

    Abstract This paper presents a proposed low-noise and high-sensitivity Internet of Thing (IoT) system based on an M&NEMS microphone. The IoT device consists of an M&NEMS resistive accelerometer associated with an electronic readout circuit, which is a silicon nanowire and a Continuous-Time (CT) Δ Σ ADC. The first integrator of the Δ Σ ADC is based on a positive feedback DC-gain enhancement two-stage amplifier due to its high linearity and low-noise operations. To mitigate both the offset and 1/f noise, a suggested delay-time chopper negative-R stabilization technique is applied around the first integrator. A 65-nm CMOS process implements the More >

  • Open Access

    ARTICLE

    Denoising Letter Images from Scanned Invoices Using Stacked Autoencoders

    Samah Ibrahim Alshathri1,*, Desiree Juby Vincent2, V. S. Hari2

    CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 1371-1386, 2022, DOI:10.32604/cmc.2022.022458 - 03 November 2021

    Abstract Invoice document digitization is crucial for efficient management in industries. The scanned invoice image is often noisy due to various reasons. This affects the OCR (optical character recognition) detection accuracy. In this paper, letter data obtained from images of invoices are denoised using a modified autoencoder based deep learning method. A stacked denoising autoencoder (SDAE) is implemented with two hidden layers each in encoder network and decoder network. In order to capture the most salient features of training samples, a undercomplete autoencoder is designed with non-linear encoder and decoder function. This autoencoder is regularized for… More >

  • Open Access

    ARTICLE

    Two-Mode Biomedical Sensor Build-up: Characterization of Optical Amplifier

    Usman Masud1,2,*, Fathe Jeribi3, Mohammed Alhameed3, Faraz Akram4, Ali Tahir3, Mohammad Yousaf Naudhani5

    CMC-Computers, Materials & Continua, Vol.70, No.3, pp. 5487-5489, 2022, DOI:10.32604/cmc.2022.020417 - 11 October 2021

    Abstract Intracavity absorption spectroscopy is a strikingly sensitive technique that has been integrated with a two-wavelength setup to develop a sensor for human breath. Various factors are considered in such a scenario, out of which Relative Intensity Noise (RIN) has been exploited as an important parameter to characterize and calibrate the said setup. During the performance of an electrical based assessment arrangement which has been developed in the laboratory as an alternative to the expensive Agilent setup, the optical amplifier plays a pivotal role in its development and operation, along with other components and their significance.… More >

  • Open Access

    ARTICLE

    An Efficient Reference Free Adaptive Learning Process for Speech Enhancement Applications

    Girika Jyoshna1,*, Md. Zia Ur Rahman1, L. Koteswararao2

    CMC-Computers, Materials & Continua, Vol.70, No.2, pp. 3067-3080, 2022, DOI:10.32604/cmc.2022.020160 - 27 September 2021

    Abstract In issues like hearing impairment, speech therapy and hearing aids play a major role in reducing the impairment. Removal of noise signals from speech signals is a key task in hearing aids as well as in speech therapy. During the transmission of speech signals, several noise components contaminate the actual speech components. This paper addresses a new adaptive speech enhancement (ASE) method based on a modified version of singular spectrum analysis (MSSA). The MSSA generates a reference signal for ASE and makes the ASE is free from feeding reference component. The MSSA adopts three key… More >

  • Open Access

    ARTICLE

    Prioritizing and Providing Sound Pollution Control Strategies at the CPF of North Azadegan Oilfield Project

    Ali Askari1, Ali Salehi Sahl Abadi2,*, Alimardan Alinia3, Milad Pourjaafar4, Aref Honairi Haghighi5, Elham Akhlaghi Pirposhteh6

    Sound & Vibration, Vol.55, No.4, pp. 329-341, 2021, DOI:10.32604/sv.2021.016662 - 18 October 2021

    Abstract Among the harmful occupational factors, noise is the most common exposure in the oil industrial workplaces. The present study aimed to prioritize sound pollution areas in central processing facilities (CPF) of an oil field in order to provide corrective action in the studied industry and similar industries. After reviewing the issued permit to work, job description and noise dosimetry test, the evaluated areas were selected then sound pressure levels in the referenced areas investigated according to ISO 9612–2009 (E) next the noise map prepared for all selected areas. For identifying the prioritized areas to implement… More >

  • Open Access

    ARTICLE

    A Material Identification Approach Based on Wi-Fi Signal

    Chao Li1, Fan Li1,2, Wei Du3, Lihua Yin1,*, Bin Wang4, Chonghua Wang5, Tianjie Luo1

    CMC-Computers, Materials & Continua, Vol.69, No.3, pp. 3383-3397, 2021, DOI:10.32604/cmc.2021.020765 - 24 August 2021

    Abstract Material identification is a technology that can help to identify the type of target material. Existing approaches depend on expensive instruments, complicated pre-treatments and professional users. It is difficult to find a substantial yet effective material identification method to meet the daily use demands. In this paper, we introduce a Wi-Fi-signal based material identification approach by measuring the amplitude ratio and phase difference as the key features in the material classifier, which can significantly reduce the cost and guarantee a high level accuracy. In practical measurement of Wi-Fi based material identification, these two features are… More >

  • Open Access

    ARTICLE

    Image Denoising Using a Nonlinear Pixel-Likeness Weighted-Frame Technique

    P. Vinayagam1,*, P. Anandan2, N. Kumaratharan3

    Intelligent Automation & Soft Computing, Vol.30, No.3, pp. 869-879, 2021, DOI:10.32604/iasc.2021.016761 - 20 August 2021

    Abstract Recent advances in the development of image denoising applications for eliminating the various sources of noise in digital images have employed hardware platforms based on field programmable gate arrays for attaining speed and efficiency, which are essential factors in real-time applications. However, image denoising providing for maximum denoising performance, speed, and efficiency on these platforms is subject to constant innovation. To this end, the present work proposes a high-throughput fixed-point adaptive edge noise filter architecture to denoise digital images with additive white Gaussian noise in realtime using a nonlinear modified pixel-likeness weighted-frame technique. The proposed More >

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