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  • Open Access

    PROCEEDINGS

    Effects of Unequal Individual Spacing on the Aerodynamic Performance of Three Flapping Wings in Tandem

    Xueguang Meng1, Zengshuang Chen1, Yuxin Xie1, Gang Chen1,*

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.4, pp. 1-5, 2023, DOI:10.32604/icces.2023.09892

    Abstract Many species generally choose highly organized movements to gain more performance advantages rather than alone in the animal world, such as V-formation and line formation in birds. Understanding the aerodynamic characteristics and flow variation of multi-flapping wings in formation flight could be applied to the formation design of new bionic flapping-wing aircraft. In this paper, the effects of unequal individual spacing on the aerodynamic performance and flow mechanism of three-dimensional three-flapping wings flying in tandem formation are investigated numerically at a low Reynolds number. The simulations include small and large spacings, as well as cases with equal and unequal spacings… More >

  • Open Access

    ARTICLE

    Electroencephalography (EEG) Based Neonatal Sleep Staging and Detection Using Various Classification Algorithms

    Hafza Ayesha Siddiqa1, Muhammad Irfan1, Saadullah Farooq Abbasi2,*, Wei Chen1

    CMC-Computers, Materials & Continua, Vol.77, No.2, pp. 1759-1778, 2023, DOI:10.32604/cmc.2023.041970

    Abstract Automatic sleep staging of neonates is essential for monitoring their brain development and maturity of the nervous system. EEG based neonatal sleep staging provides valuable information about an infant’s growth and health, but is challenging due to the unique characteristics of EEG and lack of standardized protocols. This study aims to develop and compare 18 machine learning models using Automated Machine Learning (autoML) technique for accurate and reliable multi-channel EEG-based neonatal sleep-wake classification. The study investigates autoML feasibility without extensive manual selection of features or hyperparameter tuning. The data is obtained from neonates at post-menstrual age 37 ± 05 weeks.… More >

  • Open Access

    ARTICLE

    Self-Awakened Particle Swarm Optimization BN Structure Learning Algorithm Based on Search Space Constraint

    Kun Liu1,2, Peiran Li3, Yu Zhang1,*, Jia Ren1, Xianyu Wang2, Uzair Aslam Bhatti1

    CMC-Computers, Materials & Continua, Vol.76, No.3, pp. 3257-3274, 2023, DOI:10.32604/cmc.2023.039430

    Abstract To obtain the optimal Bayesian network (BN) structure, researchers often use the hybrid learning algorithm that combines the constraint-based (CB) method and the score-and-search (SS) method. This hybrid method has the problem that the search efficiency could be improved due to the ample search space. The search process quickly falls into the local optimal solution, unable to obtain the global optimal. Based on this, the Particle Swarm Optimization (PSO) algorithm based on the search space constraint process is proposed. In the first stage, the method uses dynamic adjustment factors to constrain the structure search space and enrich the diversity of… More >

  • Open Access

    ARTICLE

    Wake-Up Security: Effective Security Improvement Mechanism for Low Power Internet of Things

    Sun-Woo Yun1, Na-Eun Park1, Il-Gu Lee1,2,*

    Intelligent Automation & Soft Computing, Vol.37, No.3, pp. 2897-2917, 2023, DOI:10.32604/iasc.2023.039940

    Abstract As time and space constraints decrease due to the development of wireless communication network technology, the scale and scope of cyberattacks targeting the Internet of Things (IoT) are increasing. However, it is difficult to apply high-performance security modules to the IoT owing to the limited battery, memory capacity, and data transmission performance depending on the size of the device. Conventional research has mainly reduced power consumption by lightening encryption algorithms. However, it is difficult to defend large-scale information systems and networks against advanced and intelligent attacks because of the problem of deteriorating security performance. In this study, we propose wake-up… More >

  • Open Access

    ARTICLE

    The Effects of Turbulence Intensity and Tip Speed Ratio on the Coherent Structure of Horizontal-Axis Wind Turbine Wake: A Wind Tunnel Experiment

    Yuxia Han1,2, Jianwen Wang1,2,*, Xin Li3, Xueqing Dong1,2, Caifeng Wen1,2

    Energy Engineering, Vol.119, No.6, pp. 2297-2317, 2022, DOI:10.32604/ee.2022.020858

    Abstract The evolution laws of the large-eddy coherent structure of the wind turbine wake have been evaluated via wind tunnel experiments under uniform and turbulent inflow conditions. The spatial correlation coefficients, the turbulence integral scales and power spectrum are obtained at different tip speed ratios (TSRs) based on the time-resolved particle image velocity (TR-PIV) technique. The results indicate that the large-eddy coherent structures are more likely to dissipate with an increase in turbulence intensity and TSR. Furthermore, the spatial correlation of the longitudinal pulsation velocity is greater than its axial counterpart, resulting into a wake turbulence dominated by the longitudinal pulsation.… More >

  • Open Access

    ARTICLE

    Magnetic Wakame-Based Biochar/Ni Composites with Enhanced Adsorption Performance for Diesel

    Hua Jing1, Shiyao Lu1, Lili Ji1,*, Shijie Li1, Baikang Zhu2, Jian Guo3, Jiaxing Sun1, Lu Cai4, Yaning Wang1

    Journal of Renewable Materials, Vol.10, No.12, pp. 3147-3165, 2022, DOI:10.32604/jrm.2022.020215

    Abstract In this study, the magnetic wakame biochar/Ni composites were prepared with three activating reagents of H3PO4, ZnCl2 and KOH by one-step pyrolysis activation, characterized by BET, SEM, TEM, FI-IR, XRD, Raman, and elemental analyzer, and their adsorption performance for diesel were also analyzed. The results showed that wakame biochar/Ni composites had larger specific surface area, abundant porous structure, and various reactive groups, rendering its enhancement of adsorption efficiency. The adsorption experiments indicated that the maximum adsorption capacities for diesel using WBPA 0.5, WBHZ 0.5 and WBPH 0.5 were 4.11, 8.83, and 13.47 g/g, respectively. The Langmuir model was more suitable… More >

  • Open Access

    ARTICLE

    A Hybrid Approach to Neighbour Discovery in Wireless Sensor Networks

    Sagar Mekala1,*, K. Shahu Chatrapati2

    Intelligent Automation & Soft Computing, Vol.35, No.1, pp. 581-593, 2023, DOI:10.32604/iasc.2023.023539

    Abstract In the contemporary era of unprecedented innovations such as Internet of Things (IoT), modern applications cannot be imagined without the presence of Wireless Sensor Network (WSN). Nodes in WSN use neighbour discovery (ND) protocols to have necessary communication among the nodes. Neighbour discovery process is crucial as it is to be done with energy efficiency and minimize discovery latency and maximize percentage of neighbours discovered. The current ND approaches that are indirect in nature are categorized into methods of removal of active slots from wake-up schedules and intelligent addition of new slots. The two methods are found to have certain… More >

  • Open Access

    ARTICLE

    Study on the Influence of a Wake Vortex on an ARJ21 Aircraft Using the Strip Method

    Weijun Pan*, Jingkai Wang, Hao Wang, Yuming Luo

    FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1495-1509, 2022, DOI:10.32604/fdmp.2022.019018

    Abstract A model for the vortex distribution in the wake of an aircraft is elaborated to investigate the wake influence on the behaviour of other aircrafts potentially interacting with it. As a realistic case, the interaction of an ARJ21 aircraft with a (leading) A330-200 aircraft is considered. Different distances are considered, namely, 6 km, 7 km, 8 km, 9.3 km, and 10 km. Simulations based on the used wake dissipation mechanism are used to investigate different conditions, namely, the ARJ21 in take-off and level flight and the changes induced in the related lift by the front aircraft A330-200 during landing. The… More > Graphic Abstract

    Study on the Influence of a Wake Vortex on an ARJ21 Aircraft Using the Strip Method

  • Open Access

    REVIEW

    Review on Research about Wake Effects of Offshore Wind Turbines

    Yehong Dong1,2, Guangyin Tang3, Yan Jia4, Zekun Wang4,5, Xiaomin Rong5, Chang Cai5, Qingan Li5, Yingjian Yang4,5,*

    Energy Engineering, Vol.119, No.4, pp. 1341-1360, 2022, DOI:10.32604/ee.2022.019150

    Abstract In recent years, the construction of offshore wind farms is developing rapidly. As the wake effect of the upstream wind turbines seriously affect the performance of the downstream wind turbines, the wake effect of offshore wind turbines has become one of the research hotspots. First, this article reviews the research methods of wake effects, including CFD numerical simulation method, wind turbine wake model based on roughness and engineering wake models. However, there is no general model that can be used directly. Then it puts forward some factors that affect the wake of offshore wind turbines. The turbulence intensity in offshore… More > Graphic Abstract

    Review on Research about Wake Effects of Offshore Wind Turbines

  • Open Access

    ARTICLE

    Discussion of the Fluid Acceleration Quality of a Ducted Propulsion System on the Propulsive Performance

    Jui-Hsiang Kao*, Yi-Fan Liao

    CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.3, pp. 1325-1348, 2022, DOI:10.32604/cmes.2022.016212

    Abstract This paper focuses on the ducted propulsion with the accelerating nozzle, and discusses the influence of its fluid acceleration quality on its propulsive performances, including the hull efficiency, the relative rotative efficiency, the effective wake, and the thrust deduction factor. An actual ducted propulsion system is used as an example for computational analysis. The computational conditions are divided into four combinations, which are provided with different propeller pitches, cambers, and duct lengths. The method applied in this study is the Computational Fluid Dynamics (CFD) technology, and the contents of the calculation include the hull's viscous resistance, the wave-making resistance, the… More >

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