Weiru Wang¹, Yulong Cao^1,*, Yanxu Wang¹, Jiale You¹, Guangnan Zhang¹, Yu Xiao²

Energy Engineering, Vol.121, No.12, pp. 3801-3823, 2024, DOI:10.32604/ee.2024.055398 - 22 November 2024

Abstract To ensure frequency stability in power systems with high wind penetration, the doubly-fed induction generator (DFIG) is often used with the frequency fast response control (FFRC) to participate in frequency response. However, a certain output power suppression amount (OPSA) is generated during frequency support, resulting in the frequency modulation (FM) capability of DFIG not being fully utilised, and the system’s unbalanced power will be increased during speed recovery, resulting in a second frequency drop (SFD) in the system. Firstly, the frequency response characteristics of the power system with DFIG containing FFRC are analysed. Then, based… More >

Aijia Ding, Tingzhang Liu^*

Energy Engineering, Vol.121, No.12, pp. 3735-3759, 2024, DOI:10.32604/ee.2024.054687 - 22 November 2024

Abstract The primary factor contributing to frequency instability in microgrids is the inherent intermittency of renewable energy sources. This paper introduces novel dual-backup controllers utilizing advanced fractional order proportional integral derivative (FOPID) controllers to enhance frequency and tie-line power stability in microgrids amid increasing renewable energy integration. To improve load frequency control, the proposed controllers are applied to a two-area interconnected microgrid system incorporating diverse energy sources, such as wind turbines, photovoltaic cells, diesel generators, and various storage technologies. A novel meta-heuristic algorithm is adopted to select the optimal parameters of the proposed controllers. The efficacy… More >

Jian Su¹, Haijian Shao^1,2,*, Xing Deng¹, Yingtao Jiang²

CMC-Computers, Materials & Continua, Vol.81, No.2, pp. 2219-2242, 2024, DOI:10.32604/cmc.2024.057604 - 18 November 2024

Abstract The rapidly advancing Convolutional Neural Networks (CNNs) have brought about a paradigm shift in various computer vision tasks, while also garnering increasing interest and application in sensor-based Human Activity Recognition (HAR) efforts. However, the significant computational demands and memory requirements hinder the practical deployment of deep networks in resource-constrained systems. This paper introduces a novel network pruning method based on the energy spectral density of data in the frequency domain, which reduces the model’s depth and accelerates activity inference. Unlike traditional pruning methods that focus on the spatial domain and the importance of filters, this… More >

Lingsheng Li¹, Weiqing Bai², Chong Han^2,*

CMC-Computers, Materials & Continua, Vol.81, No.1, pp. 1613-1640, 2024, DOI:10.32604/cmc.2024.056073 - 15 October 2024

Abstract Gestures are one of the most natural and intuitive approach for human-computer interaction. Compared with traditional camera-based or wearable sensors-based solutions, gesture recognition using the millimeter wave radar has attracted growing attention for its characteristics of contact-free, privacy-preserving and less environment-dependence. Although there have been many recent studies on hand gesture recognition, the existing hand gesture recognition methods still have recognition accuracy and generalization ability shortcomings in short-range applications. In this paper, we present a hand gesture recognition method named multiscale feature fusion (MSFF) to accurately identify micro hand gestures. In MSFF, not only the More >

Zhi Wang¹, Jinming Cao¹, Zhonglei Liu¹, Yuhong Zhao^1,2,3,*

CMC-Computers, Materials & Continua, Vol.81, No.1, pp. 213-228, 2024, DOI:10.32604/cmc.2024.055169 - 15 October 2024

Abstract Recent years, the polarization response of ferroelectrics has been entirely studied. However, it is found that the polarization may disappear gradually with the continually applied of electric field. In this paper, taking K_0.48Na_0.52NbO₃(KNN) as an example, it was demonstrated that the residual polarization began to decrease when the electric field frequency increased to a certain extent using a phase-field methods. The results showed that the content of out-of-plane domains increased first and then decreased with the increase of applied electric field frequency, the maximum polarization disappeared at high frequencies, and the hysteresis loop became elliptical. In More >

Yi Shi^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.012366

Abstract The Nickel-based superalloy is wieldy applied in hot components of aero turbine engine due to its superior mechanical property at elevated temperature. However, the working condition of engine hot components are severe and thus the effect of high temperature, oxidation and time-dependent loading on fatigue crack growth behavior should be considered in structure analysis. In this study, first the effect of environment was experimentally investigated. Stand compact tension (CT) specimens under different temperatures and loading frequencies were tests to evaluate the role of temperature and time-dependent effect on fatigue crack growth. Results show that if… More >

Binjie Mu¹, Jun Liu^2,*, Yuanfang Chen¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.4, pp. 1-2, 2024, DOI:10.32604/icces.2024.011110

Abstract With the improvement of aircraft design requirements, the development of airborne equipment towards lightweight, miniaturization and weight reduction has brought great challenges to the structural design of airborne equipment. Usually, airborne equipment needs to be connected to the fuselage through supporting brackets. In the process of airplane flight, due to the influence of vibration and other complex load conditions, the mounting bracket of airborne equipment is prone to damage caused by the unreasonable structural design of airborne equipment. Some sensitive airborne electronic equipment has special requirements for the dynamic characteristics of the bracket. Therefore, the… More >

Santhanakrishnan Mamallan¹, Venkateshwaran Narayanan^1,*, Canungo Bhimarao Ragothaman²

Journal of Polymer Materials, Vol.41, No.3, pp. 105-116, 2024, DOI:10.32604/jpm.2024.056744 - 30 September 2024

Abstract Glass fabric/polymer composites are widely used in various industrial applications due to their lightweight, exceptional strength, and fatigue resistance. Graphene nanoplatelets, a recently developed type of carbon material, stand out as unique nanofillers due to their 2D quantum confinement and expansive surface area within a polymer matrix. These features make them more effective than traditional carbon nanofillers at enhancing a range of properties. In this study, 3-weight % of graphene nanoplatelets with epoxy resin were used for investigation by varying sonication durations (0, 20, 40, and 60 min) using an ultrasonic bath sonicator. The laminates More >

Ayesha Khaliq¹, Salman Afsar Awan¹, Fahad Ahmad^2,*, Muhammad Azam Zia¹, Muhammad Zafar Iqbal³

CMC-Computers, Materials & Continua, Vol.80, No.2, pp. 3221-3242, 2024, DOI:10.32604/cmc.2024.053488 - 15 August 2024

Abstract The rapid expansion of online content and big data has precipitated an urgent need for efficient summarization techniques to swiftly comprehend vast textual documents without compromising their original integrity. Current approaches in Extractive Text Summarization (ETS) leverage the modeling of inter-sentence relationships, a task of paramount importance in producing coherent summaries. This study introduces an innovative model that integrates Graph Attention Networks (GATs) with Transformer-based Bidirectional Encoder Representations from Transformers (BERT) and Latent Dirichlet Allocation (LDA), further enhanced by Term Frequency-Inverse Document Frequency (TF-IDF) values, to improve sentence selection by capturing comprehensive topical information. Our… More >

Xu Zhang¹, Yi He¹, Haiwen Yi¹, Yulu Zhang², Yuan Li², Shuai Ma², Gui Li³, Zhiyuan Zhao⁴, Yue Liu¹, Junyang Liu¹, Guangjun Wen¹, Jian Li^1,*

CMC-Computers, Materials & Continua, Vol.80, No.1, pp. 897-912, 2024, DOI:10.32604/cmc.2024.050000 - 18 July 2024

Abstract When the radio frequency identification (RFID) system inventories multiple tags, the recognition rate will be seriously affected due to collisions. Based on the existing dynamic frame slotted Aloha (DFSA) algorithm, a sub-frame observation and cyclic redundancy check (CRC) grouping combined dynamic framed slotted Aloha (SUBF-CGDFSA) algorithm is proposed. The algorithm combines the precise estimation method of the quantity of large-scale tags, the large-scale tags grouping mechanism based on CRC pseudo-random characteristics, and the Aloha anti-collision optimization mechanism based on sub-frame observation. By grouping tags and sequentially identifying them within subframes, it accurately estimates the number More >