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  • Open Access


    Dynamic Active Noise Control of Broadband Noise in Fighter Aircraft Pilot Helmet

    Y. K. Bharath1,*, S. Veena2

    Sound & Vibration, Vol.56, No.4, pp. 319-331, 2022, DOI:10.32604/sv.2022.015634

    Abstract This paper presents the development of a dynamic Active Noise Control (ANC) algorithm aimed towards reducing the broadband noise inside the helmet earcups of a fighter aircraft pilot helmet. The dynamic ANC involves a Variable Step-Size Griffiths (VSSG) FxLMS algorithm to attenuate noise entering directly through helmet, a LMS based adaptive noise canceller to attenuate noise entering through the pilot microphone, and energy detectors for failure protection and optimized battery power usage. The algorithms are implemented on Texas Instruments’ TMS320C6748 processor and are tested in a helmet ANC experimental setup. More >

  • Open Access


    Graphene-Based Active Tunable Metasurfaces for Dynamic Terahertz Absorption and Polarization Conversion

    Haoran Wei, Tian Ji, Jianqing Huang*

    Journal of Renewable Materials, Vol.11, No.2, pp. 731-743, 2023, DOI:10.32604/jrm.2022.022283

    Abstract Simultaneous broadband absorption and polarization conversion are crucial in many practical applications, especially in terahertz communications. Thus, actively tunable metamaterial systems can exploit the graphene-based nanomaterials derived from renewable resources because of the flexible surface conductivity and selective permeability of the nanomaterials at terahertz frequencies. In this paper, we propose a graphene-based active tunable bifunctional metasurface for dynamic terahertz absorption and polarization conversion. The graphene ring presents a certain opening angle (A) along the diagonal of the xoy plane. When A = 0°, the proposed metasurface behaves as a broadband absorber. Numerical results show the feasibility of achieving this polarization-insensitive… More >

  • Open Access


    Coupled CUBIC Congestion Control for MPTCP in Broadband Networks

    Jae Yong Lee1, Byung Chul Kim1, Youngmi Kwon1,*, Kimoon Han2

    Computer Systems Science and Engineering, Vol.45, No.1, pp. 99-115, 2023, DOI:10.32604/csse.2023.030801

    Abstract Recently, multipath transmission control protocol (MPTCP) was standardized so that data can be transmitted through multiple paths to utilize all available path bandwidths. However, when high-speed long-distance networks are included in MPTCP paths, the traffic transmission performance of MPTCP is severely deteriorated, especially in case the multiple paths’ characteristics are heavily asymmetric. In order to alleviate this problem, we propose a “Coupled CUBIC congestion control” that adopts TCP CUBIC on a large bandwidth-delay product (BDP) path in a linked increase manner for maintaining fairness with an ordinary TCP traversing the same bottleneck path. To verify the performance excellence of the… More >

  • Open Access


    CNTFET Based Grounded Active Inductor for Broadband Applications

    Muhammad I. Masud1,2,*, Nasir Shaikh-Husin2, Iqbal A. Khan1, Abu K. Bin A’Ain2

    CMC-Computers, Materials & Continua, Vol.73, No.1, pp. 2135-2149, 2022, DOI:10.32604/cmc.2022.026831

    Abstract A new carbon nanotube field effect transistor (CNTFET) based grounded active inductor (GAI) circuit is presented in this work. The suggested GAI offers a tunable inductance with a very wide inductive bandwidth, high quality factor (QF) and low power dissipation. The tunability of the realized circuit is achieved through CNTFET based varactor. The proposed topology shows inductive behavior in the frequency range of 0.1–101 GHz and achieves to a maximum QF of 9125. The GAI operates at 0.7 V with 0.337 mW of power consumption. To demonstrate the performance of GAI, a broadband low noise amplifier (LNA) circuit is designed by utilizing… More >

  • Open Access


    Mean Opinion Score Estimation for Mobile Broadband Networks Using Bayesian Networks

    Ayman A. El-Saleh1, Abdulraqeb Alhammadi2,*, Ibraheem Shayea3, Azizul Azizan4, Wan Haslina Hassan2

    CMC-Computers, Materials & Continua, Vol.72, No.3, pp. 4571-4587, 2022, DOI:10.32604/cmc.2022.024642

    Abstract Mobile broadband (MBB) networks are expanding rapidly to deliver higher data speeds. The fifth-generation cellular network promises enhanced-MBB with high-speed data rates, low power connectivity, and ultra-low latency video streaming. However, existing cellular networks are unable to perform well due to high latency and low bandwidth, which degrades the performance of various applications. As a result, monitoring and evaluation of the performance of these network-supported services is critical. Mobile network providers optimize and monitor their network performance to ensure the highest quality of service to their end-users. This paper proposes a Bayesian model to estimate the minimum opinion score (MOS)… More >

  • Open Access


    Polarization Insensitive Broadband Zero Indexed Nano-Meta Absorber for Optical Region Applications

    Ismail Hossain1, Md Samsuzzaman2, Ahasanul Hoque3, Mohd Hafiz Baharuddin3, Norsuzlin Binti Mohd Sahar1, Mohammad Tariqul Islam3,*

    CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 993-1009, 2022, DOI:10.32604/cmc.2022.021435

    Abstract Broadband response metamaterial absorber (MMA) remains a challenge among researchers. A nanostructured new zero-indexed metamaterial (ZIM) absorber is presented in this study, constructed with a hexagonal shape resonator for optical region applications. The design consists of a resonator and dielectric layers made with tungsten and quartz (Fused). The proposed absorbent exhibits average absorption of more than 0.8972 (89.72%) within the visible wavelength of 450–600 nm and nearly perfect absorption of 0.99 (99%) at 461.61 nm. Based on computational analysis, the proposed absorber can be characterized as ZIM. The developments of ZIM absorbers have demonstrated plasmonic resonance characteristics and a perfect… More >

  • Open Access


    Helix Inspired 28 GHz Broadband Antenna with End-Fire Radiation Pattern

    Hijab Zahra1, Wahaj Abbas Awan2, Niamat Hussain3,*, Syed Muzahir Abbas1,4, Subhas Mukhopadhyay1

    CMC-Computers, Materials & Continua, Vol.70, No.1, pp. 1935-1944, 2022, DOI:10.32604/cmc.2022.019495

    Abstract This paper presents the design and characterization of a via free planar single turn helix for 28 GHz broadband applications. The proposed antenna is designed using ROGERS RO4003 material, having a simple structure and end-fire radiation pattern. The antenna comprises of a compact dimension of 1.36 λ0 × 0.9 λ0 with a thickness of 0.0189 λ0 (where λ0 is the free-space wavelength at the central frequency of 28 GHz). Parametric study has been carried out to investigate the impact of key design parameters and to achieve an optimum design. Results show a good agreement between the simulated and measured results.… More >

  • Open Access


    Improving Functionality of 2DOF Piezoelectric Cantilever for Broadband Vibration Energy Harvesting Using Magnets

    Junxiang Jiang1,2, Shaogang Liu1,*, Lifeng Feng3

    Energy Engineering, Vol.118, No.5, pp. 1287-1303, 2021, DOI:10.32604/EE.2021.015354

    Abstract This paper presents a 2DOF nonlinear piezoelectric energy harvester for improving the efficiency of energy harvesting in low frequency range. The device consisted of an L-shaped piezoelectric cantilever with a magnet at the tip of the first beam and two external magnets on the pedestal. The distance between the magnets which generated nonlinear magnetic attraction was adjusted such that the system can exhibit monostable or bistable characteristics. First, the model of this piezoelectric energy harvester was established and the dynamic equation was derived based on the magnetic attractive force. Then, the nonlinear dynamic responses of the system subject to harmonic… More >

  • Open Access


    A Novel Broadband Antenna Design for 5G Applications

    Omar A. Saraereh*

    CMC-Computers, Materials & Continua, Vol.67, No.1, pp. 1121-1136, 2021, DOI:10.32604/cmc.2021.015066

    Abstract Wireless communication is one of the rapidly-growing fields of the communication industry. This continuous growth motivates the antenna community to design new radiating structures to meet the needs of the market. The 5G wireless communication has received a lot of attention from both academia and industry and significant efforts have been made to improve different aspects, such as data rate, latency, mobility, reliability and QoS. Antenna design has received renewed attention in the last decade due to its potential applications in 5G, IoT, mmWave, and massive MIMO. This paper proposes a novel design of broadband antenna for 5G mmWave and… More >

  • Open Access


    Unsupervised Time-series Fatigue Damage State Estimation of Complex Structure Using Ultrasound Based Narrowband and Broadband Active Sensing

    S.Mohanty1, A. Chattopadhyay2, J. Wei3, P. Peralta4

    Structural Durability & Health Monitoring, Vol.5, No.3, pp. 227-250, 2009, DOI:10.3970/sdhm.2009.005.227

    Abstract This paper proposes unsupervised system identification based methods to estimate time-series fatigue damage states in real-time. Ultrasound broadband input is used for active damage interrogation. Novel damage index estimation techniques based on dual sensor signals are proposed. The dual sensor configuration is used to remove electrical noise, as well as to improve spatial resolution in damage state estimation. The scalar damage index at any particular damage condition is evaluated using nonparametric system identification techniques, which includes an empirical transfer function estimation approach and a correlation analysis approach. In addition, the effectiveness of two sensor configurations (configuration 1: sensors placed near… More >

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