Engineering Science and Technology-An International Journal-Jestech最新文献_第7页

A road map of 3D entropy generated rotating hybrid nanoliquid flow with nonlinear thermal radiation 具有非线性热辐射的旋转混合纳米流体三维熵路径图

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-25 DOI: 10.1016/j.jestch.2025.102209

Aqsa Razzaq , T. Hayat , Sajjad Shaukat Jamal , Sohail A. Khan , Aneeta Razaq

Nanotechnology has significant applications in various fields like nuclear reactor, paper production, metal spinning, heat transport and storage devices, power generation, renewable energy and many others. Hybrid nanomaterial in comparison to classical nanoliquid is impressive to enhance thermal transport rate. Hybrid nanoliquid has significant role in various applications using their innovative characteristics to develop performance, efficiency, functionality and stability in various industrial, engineering and scientific processes. Present communication addresses three-dimensional magnetohydrodynamic (MHD) flow of hybrid nanofluid in rotating frame. Flow is constructed to scrutinize thermal transport characteristics of hybrid nanoliquid and nanoliquid. Here manganese nickel zinc ferrite and zinc ferrite are employed as the nanoparticles. Engine oil is used as conventional liquid. Non-linear thermal radiation and non-uniform heat source/sink features are discussed. Thermal expression consists of non-uniform heat source/sink, magnetohydrodynamics and non-linear radiation. Entropy generation rate in presence of non-uniform heat source/sink is discussed. Related non-linear expressions of proposed model are converted into dimensionless systems through adequate transformations. Resultant non-linear ordinary systems are computed for numerical solutions through utilizing ND-solve technique. Graphical features for velocity, rate of entropy and temperature for influential variables regarding both nanoliquid and hybrid nanoliquid are analyzed. Outcomes of quantities against pertinent variables for both fluids are graphically analyzed. Larger magnetic field leads to rise the entropy rate and thermal field, whereas decreasing impact for velocity is witnessed. Larger approximation of radiation intensify Nusselt number and entropy rate. Revers impact for Nusselt number and temperature through non-uniform heat source variable is witnessed. Here one can conclude that thermal transport rate and temperature distribution for hybrid nanoliquid is higher when compared with nanoliquid. Drag force coefficient of hybrid nanoliquid is more dominant than nanoliquid.

纳米技术在核反应堆、造纸、金属纺丝、热传输和存储设备、发电、可再生能源等许多领域都有重要的应用。与传统纳米液体相比，杂化纳米液体在提高热输运率方面表现突出。混合纳米液体利用其创新特性在各种工业、工程和科学过程中开发性能、效率、功能和稳定性，在各种应用中发挥着重要作用。本文讨论了混合纳米流体在旋转框架中的三维磁流体动力学（MHD）流动。建立了流动模型，考察了混合纳米液体和纳米液体的热输运特性。本文采用锰镍锌铁氧体和锌铁氧体作为纳米颗粒。发动机油作为常规液体使用。讨论了非线性热辐射和非均匀热源/汇特征。热表达式包括非均匀热源/热源、磁流体力学和非线性辐射。讨论了非均匀热源/热源存在时的熵产率。通过适当的变换，将模型的相关非线性表达式转化为无量纲系统。利用nd -解技术，计算了所得非线性普通系统的数值解。分析了纳米液体和杂化纳米液体的速度、熵率和温度等影响变量的图形特征。对两种流体的相关变量的数量结果进行了图形化分析。磁场增大导致熵率和热场增大，而对速度的影响减小。更大的近似辐射增强努塞尔数和熵率。研究了非均匀热源变量对努塞尔数和温度的影响。由此可见，混合纳米液体的热输运率和温度分布高于纳米液体。混合纳米液体的阻力系数比纳米液体更占优势。

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引用次数: 0

Advanced deep reinforcement learning for optimizing 3D printing toolpaths: A framework with enhanced agent architectures, Count-Prioritized Replay, and curriculum learning 用于优化3D打印工具路径的高级深度强化学习：具有增强代理架构、计数优先重放和课程学习的框架

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-24 DOI: 10.1016/j.jestch.2025.102205

Ahmed Merze , Fatih Vehbi Çelebi

Optimizing toolpaths in 3D printing presents a significant challenge for achieving efficient and high-quality prints. In this study, a novel deep reinforcement learning (DRL) framework is proposed to overcome this problem. A core component of this framework is the proposed agent: Count-Prioritized Replay Deep Q-Network (CPR-DQN). The first key contribution is a developed simulation environment called PrintBoardEnv, which has curriculum learning built in. Secondly, a new method is developed for experience replay called Count-Prioritized Replay (CPR). The third key development is the CPR-DQN agent itself that uses a special architecture which includes features like Implicit Quantile Networks (IQN), Munchausen RL, Dueling, and Noisy Networks. Our agent is trained in two stages respectively, which is an offline pre-training, and then an online training. Our CPR-DQN agent is compared with other agents like DQN, Rainbow DQN, and Beyond The Rainbow (BTR). Furthermore, it is demonstrated that the CPR-DQN agent achieves great performance, highlighting the benefits of the proposed framework for toolpath optimization.

优化3D打印中的工具路径是实现高效和高质量打印的重大挑战。在本研究中，提出了一种新的深度强化学习（DRL）框架来克服这个问题。该框架的核心组件是提出的代理：计数优先重放深度q网络（CPR-DQN）。第一个关键贡献是开发了一个名为PrintBoardEnv的模拟环境，其中内置了课程学习。其次，提出了一种新的经验重播方法——计数优先重播（CPR）。第三个关键的发展是pr - dqn代理本身，它使用了一种特殊的架构，其中包括隐式分位数网络（IQN）、Munchausen强化学习、决斗和噪声网络等功能。我们的agent的训练分为两个阶段，一个是离线预训练，一个是在线训练。我们的CPR-DQN代理与DQN、Rainbow DQN和Beyond The Rainbow （BTR）等其他代理进行了比较。此外，还证明了CPR-DQN代理取得了良好的性能，突出了所提出的框架在刀具路径优化方面的优势。

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引用次数: 0

Evolution mechanisms of residual stress in roll bending process for large-scale aerospace integral structures 大型航空航天整体结构轧辊弯曲过程中残余应力的演化机制

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-24 DOI: 10.1016/j.jestch.2025.102214

Yuhang Duan , Jianfeng Wang , Shulin Lu , Lihong Cheng , Shuwen Huang , Kun Zhou , Yaobang Zhao , Junchen Li , Xiaohong Zhan

Controlling residual stress distribution during roll bending is essential for manufacturing high-precision components, such as rocket propellant tanks. However, the mechanisms governing stress evolution in this process remain insufficiently understood, which limits the development of effective control strategies. This study introduces a novel full-scale finite element model of a 4.7 m rocket tank panel, rigorously validated against experimental stress measurements, to reveal the governing mechanisms of residual stress development. Unlike prior studies limited to small-scale or simplified geometries, this work systematically clarifies the coupled influence of roller down displacement and roller spacing on stress evolution. Two novel optimization pathways are identified: (i) intermediate roller displacement (15–20 mm) reduces peak residual stress by 15–20 % through suppressing localized deformation; and (ii) optimal roller spacing (500–550 mm) enhances stress uniformity, reducing equivalent plastic strain by 30–40 %. Moreover, combined parameter optimization (17.5–20 mm displacement with 500–550 mm spacing) lowers critical zone stresses below 30 MPa, significantly improving dimensional stability. These findings not only establish the first validated full-scale stress evolution model for roll bending but also deliver practical, quantitative guidelines for stress control in large aerospace structures.

控制辊弯过程中的残余应力分布对于制造高精度部件（如火箭推进剂储罐）至关重要。然而，在这一过程中控制应力演变的机制仍然不够清楚，这限制了有效控制策略的发展。本文介绍了一种新颖的4.7 m火箭燃料箱面板的全尺寸有限元模型，并通过实验应力测量进行了严格验证，以揭示残余应力发展的控制机制。与以往的研究局限于小规模或简化的几何形状不同，这项工作系统地阐明了滚子下位移和滚子间距对应力演化的耦合影响。确定了两种新的优化路径：(i)中间辊位移（15-20 mm）通过抑制局部变形，使峰值残余应力降低15 - 20%；（ii）最佳辊距（500-550 mm）提高应力均匀性，减少等效塑性应变30 - 40%。此外，组合参数优化（17.5 ~ 20mm位移，500 ~ 550 mm间距）使临界区应力低于30 MPa，显著提高了尺寸稳定性。这些发现不仅建立了第一个经过验证的轧辊弯曲全尺寸应力演化模型，而且为大型航空航天结构的应力控制提供了实用的定量指导。

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引用次数: 0

HybridNet: Advancing MRI image quality using dense attention and deep learning HybridNet：利用密集注意力和深度学习提高MRI图像质量

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-15 DOI: 10.1016/j.jestch.2025.102186

Seshagiri Rao Sugguna, Sumesh E.P

Magnetic Resonance Imaging (MRI) is widely used for brain disease diagnosis due to its superior tissue contrast, but low-field MRI scanners often generate low-resolution images that hinder accurate interpretation. Extending scan time or upgrading to high-field systems increases cost and patient discomfort, making them impractical solutions. Deep learning-based super-resolution has emerged as a promising alternative; however, conventional CNN and GAN-based models frequently oversmooth details, introduce artifacts, or rely on synthetic downsampling, thereby limiting their clinical reliability. To address these challenges, we propose HybridNet, a novel CNN-based framework that integrates even–odd pixel decomposition with Dense Attention Blocks (DABs) to capture both global structural consistency and fine anatomical details. The novelty of HybridNet lies in its dual-focus strategy pixel decomposition to preserve structural integrity and reduce aliasing, and dense attention integration to highlight diagnostically significant regions, resulting in sharper and more reliable MRI reconstructions. The objectives of this study includes — design a clinically reliable MRI super-resolution framework that minimizes artifacts and oversmoothing, to ensure generalization across different scanners and acquisition settings, and to provide perceptually faithful reconstructions that aid radiological interpretation without increasing scan time or hardware cost. Proposed HybridNet model is trained on real paired MRI datasets from different scanners, The result demonstrates strong robustness and diagnostic relevance in both Quantitative and qualitative aspects. Quantitative evaluations reveal an improvement of 6–15 dB in PSNR and 2%–4% in SSIM compared to state-of-the-art methods such as SRCNN, FSRCNN, VDSR, and EDSR. Ablation studies further confirm the role of pixel decomposition, attention integration, and feature fusion in enhancing performance. Radiologists’ subjective assessments also validate superior perceptual quality, achieving a Mean Opinion Score of 87.3 and a Perceptual Evaluation score of 73.35. Overall, HybridNet offers a cost-effective and clinically practical solution for enhancing MRI image quality.

磁共振成像（MRI）由于其优越的组织对比度被广泛用于脑部疾病的诊断，但低场MRI扫描仪通常产生低分辨率的图像，阻碍了准确的解释。延长扫描时间或升级到高视场系统会增加成本和患者不适，使其成为不切实际的解决方案。基于深度学习的超分辨率已经成为一种很有前途的替代方案；然而，传统的基于CNN和gan的模型经常过于平滑细节，引入伪影，或依赖于合成下采样，从而限制了它们的临床可靠性。为了应对这些挑战，我们提出了HybridNet，这是一种基于cnn的新型框架，它将奇偶像素分解与密集注意块（DABs）集成在一起，以捕获全局结构一致性和精细解剖细节。HybridNet的新颖之处在于其双焦点策略：像素分解以保持结构完整性并减少混叠；密集注意力整合以突出诊断重要区域，从而获得更清晰、更可靠的MRI重建。本研究的目标包括设计一个临床可靠的MRI超分辨率框架，最大限度地减少伪影和过度平滑，确保不同扫描仪和采集设置的通用性，并提供感知上忠实的重建，帮助放射学解释，而不增加扫描时间或硬件成本。所提出的HybridNet模型在来自不同扫描仪的真实配对MRI数据集上进行了训练，结果显示在定量和定性方面具有很强的鲁棒性和诊断相关性。定量评估显示，与SRCNN、FSRCNN、VDSR和EDSR等最先进的方法相比，PSNR提高了6-15 dB， SSIM提高了2%-4%。消融研究进一步证实了像素分解、注意力整合和特征融合在提高性能方面的作用。放射科医生的主观评价也证实了更高的感知质量，平均意见得分为87.3分，感知评价得分为73.35分。总的来说，HybridNet为增强MRI图像质量提供了一种具有成本效益和临床实用性的解决方案。

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引用次数: 0

Design of SynRM and PMaSynRM using a common industrial stator platform: a new design methodology for transition from industrial applications to electric vehicles 使用通用工业定子平台设计SynRM和PMaSynRM：一种从工业应用过渡到电动汽车的新设计方法

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-14 DOI: 10.1016/j.jestch.2025.102204

Sinan Suli , Yasemin Öner , İbrahim Şenol

This study presents a design methodology for synchronous reluctance (SynRM) and permanent magnet-assisted synchronous reluctance motors (PMaSynRM), developed through rotor lamination optimizations without altering the existing stator platform. This approach enables the realization of different motor types using a common stator, eliminating the need for additional tooling costs in the production line. It is based on the principle of “Efficiency Class Upgrade with Minimum Die Cost”, whereby the existing tooling infrastructure is preserved, and higher-efficiency motors are prototyped at low cost through topological modifications in the rotor design.

Using a multi-objective genetic algorithm (MOGA), rotor designs were optimized to achieve Pareto-optimal solutions among conflicting targets such as torque production, efficiency, magnet volume, and torque ripple. The electromagnetic performance of rotor geometries was assessed via 2D finite element analysis (FEA), providing flux distribution, torque profiles, and efficiency curves.

A reference IE2-class induction motor (IM) was used as the baseline, upon which SynRM and PMaSynRM models were designed using the same stator. These three motor types were comparatively analyzed, along with a dimensional-level comparison against the IE4 version of the same motor. Throughout the process, the stator geometry, slot structure, and winding features remained unchanged, ensuring design novelty through rotor-side innovations.

The results demonstrate the electromagnetic potential and structural compatibility of SynRM and PMaSynRM configurations with the existing stator. The proposed method offers a scalable and cost-effective solution for manufacturers aiming to adopt high-efficiency motor technologies, paving a transition path from industrial motors to electric vehicle (EV) applications via a unified stator platform.

This study is limited to an IE2-class, frame-90, four-pole squirrel-cage IM stator reference; applying the methodology to other frame sizes and pole counts requires re-parameterization. From a practical standpoint, redesigning only the rotor eliminates stator/winding tooling costs, enabling efficiency-class upgrades and making the approach suitable for rapid industrial adoption. From a social perspective, higher efficiency and reduced dependence on rare-earth materials contribute to energy savings and supply-chain sustainability.

本研究提出了一种同步磁阻电机（SynRM）和永磁辅助同步磁阻电机（PMaSynRM）的设计方法，该方法是在不改变现有定子平台的情况下，通过转子层压优化开发的。这种方法可以使用一个共同的定子实现不同类型的电机，从而消除了生产线上额外的模具成本。它是基于“效率级升级与最低的模具成本”的原则，即现有的工具基础设施得到保留，并通过在转子设计的拓扑修改，以低成本更高效率的电机原型。采用多目标遗传算法（MOGA）对转子设计进行优化，在转矩产生、效率、磁体体积和转矩脉动等相互冲突的目标之间实现帕累托最优解。通过二维有限元分析（FEA）评估转子几何形状的电磁性能，提供磁链分布、转矩分布和效率曲线。以参考ie2级感应电机（IM）为基准，在此基础上设计了采用同一定子的SynRM和PMaSynRM型号。对这三种电机类型进行了比较分析，并与IE4版本的相同电机进行了尺寸级比较。在整个过程中，定子的几何形状、槽结构和绕组特征保持不变，通过转子侧的创新确保了设计的新颖性。结果证明了SynRM和PMaSynRM两种构型与现有定子的电磁势和结构兼容性。该方法为旨在采用高效电机技术的制造商提供了一种可扩展且经济高效的解决方案，通过统一的定子平台，为从工业电机到电动汽车（EV）应用的过渡铺平了道路。本研究仅限于ie2级，框架90，四极鼠笼型IM定子参考；将该方法应用于其他帧尺寸和杆数需要重新参数化。从实用的角度来看，仅重新设计转子可以消除定子/绕组的模具成本，实现效率级升级，使该方法适合快速工业采用。从社会角度来看，提高效率和减少对稀土材料的依赖有助于节约能源和供应链的可持续性。

{"title":"Design of SynRM and PMaSynRM using a common industrial stator platform: a new design methodology for transition from industrial applications to electric vehicles","authors":"Sinan Suli , Yasemin Öner , İbrahim Şenol","doi":"10.1016/j.jestch.2025.102204","DOIUrl":"10.1016/j.jestch.2025.102204","url":null,"abstract":"<div><div>This study presents a design methodology for synchronous reluctance (SynRM) and permanent magnet-assisted synchronous reluctance motors (PMaSynRM), developed through rotor lamination optimizations without altering the existing stator platform. This approach enables the realization of different motor types using a common stator, eliminating the need for additional tooling costs in the production line. It is based on the principle of “Efficiency Class Upgrade with Minimum Die Cost”, whereby the existing tooling infrastructure is preserved, and higher-efficiency motors are prototyped at low cost through topological modifications in the rotor design.</div><div>Using a multi-objective genetic algorithm (MOGA), rotor designs were optimized to achieve Pareto-optimal solutions among conflicting targets such as torque production, efficiency, magnet volume, and torque ripple. The electromagnetic performance of rotor geometries was assessed via 2D finite element analysis (FEA), providing flux distribution, torque profiles, and efficiency curves.</div><div>A reference IE2-class induction motor (IM) was used as the baseline, upon which SynRM and PMaSynRM models were designed using the same stator. These three motor types were comparatively analyzed, along with a dimensional-level comparison against the IE4 version of the same motor. Throughout the process, the stator geometry, slot structure, and winding features remained unchanged, ensuring design novelty through rotor-side innovations.</div><div>The results demonstrate the electromagnetic potential and structural compatibility of SynRM and PMaSynRM configurations with the existing stator. The proposed method offers a scalable and cost-effective solution for manufacturers aiming to adopt high-efficiency motor technologies, paving a transition path from industrial motors to electric vehicle (EV) applications via a unified stator platform.</div><div>This study is limited to an IE2-class, frame-90, four-pole squirrel-cage IM stator reference; applying the methodology to other frame sizes and pole counts requires re-parameterization. From a practical standpoint, redesigning only the rotor eliminates stator/winding tooling costs, enabling efficiency-class upgrades and making the approach suitable for rapid industrial adoption. From a social perspective, higher efficiency and reduced dependence on rare-earth materials contribute to energy savings and supply-chain sustainability.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"71 ","pages":"Article 102204"},"PeriodicalIF":5.4,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

In-band spurious suppression in first-order antisymmetric-mode resonators using air holes and half electrode 利用空穴和半电极抑制一阶反对称模谐振器带内杂散

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-14 DOI: 10.1016/j.jestch.2025.102207

Shitao Lv , Dongchen Sui , Qiner Xu , Yi Cao , Qiang Xu , Haiyan Sun , Tengfei Xu , Jicong Zhao

Laterally excited bulk acoustic resonator (XBAR) exhibits a high electromechanical coupling coefficient (k_t²) due to their intrinsically superior piezoelectric properties, which is highly advantageous for the subsequent design and implementation of acoustic filters. However,it is not yet suitable for commercial application due to its numerous spurious modes and low quality factor (Q value). This paper presents an exhaustive analysis of the origins of in-band spurious modes and the method to suppress based on the first-order antisymmetric (A1) mode XBAR. Simulation results indicate that these spurious modes primarily originate from acoustic wave scattering along unintended propagation paths and standing waves caused by crosstalk between electrodes. These spurious modes lead to energy dissipation, thereby reducing the resonator’s Q value. To effectively suppress them without increasing fabrication complexity while significantly enhancing the Q value, an etching-hole strategy is proposed, introducing the transverse holes that create acoustic impedance mismatch based on velocity differences. Additionally, the adoption of a half electrode configuration optimizes the electric field and stress redistribution within the resonator, thereby effectively reducing interfacial losses at the electrode-piezoelectric layer interface and enhancing the Q value by approximately 3.5 times. The fabricated XBAR, integrating holes and half electrode configuration, exhibits an in-band spurious-free response, a Bode-Q value of 1954, a k_t² of 27.5 % and an exceptionally high figure of merit (FOM = k_t² × Bode-Q) of 537.

横向激发体声谐振器（XBAR）由于其固有的优异压电特性而具有较高的机电耦合系数（kt2），这对后续声滤波器的设计和实现非常有利。但由于其杂散模式多，质量因子（Q值）低，尚不适合商业应用。本文详细分析了带内杂散模的来源，并提出了一阶反对称（A1）模XBAR的抑制方法。仿真结果表明，这些杂散模式主要来源于非预期传播路径上的声波散射和电极间串扰引起的驻波。这些伪模导致能量耗散，从而降低了谐振器的Q值。为了在不增加制造复杂性的同时有效地抑制它们，同时显著提高Q值，提出了一种蚀刻孔策略，该策略引入了基于速度差产生声阻抗失配的横向孔。此外，采用半电极结构优化了谐振腔内的电场和应力分布，从而有效降低了电极-压电层界面处的界面损耗，使Q值提高了约3.5倍。所制备的XBAR集成了孔和半电极结构，具有带内无杂散响应，波德q值为1954，kt2为27.5%，优异值（FOM = kt2 ×波德q）为537。

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引用次数: 0

Rotational symmetric metamaterial structure of emblemed number connected with continuous transmission line for EM wave shielding applications 连接连续传输线的带符号数旋转对称超材料结构，用于屏蔽电磁波

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-09 DOI: 10.1016/j.jestch.2025.102200

Md. Ismail Hossen , Saif Hannan , Mohammad Tariqul Islam , Abdulmajeed M. Alenezi , Mohamed S. Soliman

Electromagnetic (EM) wave shielding in modern wireless systems encounters critical challenges, including polarization insensitivity, broadband operation, and compact design requirements. This work introduces a rotationally symmetric metamaterial absorber featuring emblem-shaped continuous transmission line resonators, specifically engineered to achieve high-efficiency absorption across the C, X, and Ku bands. The proposed design demonstrates remarkable absorption rates of 96.77 %, 99.68 %, 99.68 %, 99.70 %, 98.03 %, 99.68 %, and 99.98 % at resonance frequencies of 5.834 GHz, 7.192 GHz, 7.766 GHz, 10.65 GHz, 14.038 GHz, 15.34 GHz, and 15.62 GHz, respectively. Benefiting from rotational symmetry, the absorber maintains complete insensitivity to both co- and cross-polarized incident waves, with stable performance under oblique angles up to 90°. A maximum shielding effectiveness of 78 dB is achieved at the targeted frequencies, ensuring robust protection against EM interference. The compact unit cell (0.233λ × 0.233λ) exhibits near-zero permittivity, permeability, and refractive index with single-negative properties, further supporting efficient absorption within a minimal footprint. To validate the physical behavior, an equivalent RLC circuit model was developed in ADS, showing excellent agreement with CST simulations. Experimental verification using fabricated prototypes and Vector Network Analyzer measurements confirms the strong consistency between simulated and measured results. The novelty of this work lies in the integration of an emblem-shaped resonator with a continuous transmission line in a rotationally symmetric layout, enabling broadband absorption, polarization, and angle insensitivity, as well as high shielding effectiveness within a compact geometry. These features make the proposed absorber highly suitable for Wi-Fi, 5G, aerospace, defense radar, and stealth EM shielding applications.

现代无线系统中的电磁（EM）波屏蔽面临着严峻的挑战，包括极化不敏感、宽带操作和紧凑的设计要求。这项工作介绍了一种旋转对称的超材料吸收器，具有徽章形状的连续传输线谐振器，专门设计用于实现C， X和Ku波段的高效吸收。在5.834 GHz、7.192 GHz、7.766 GHz、10.65 GHz、14.038 GHz、15.34 GHz和15.62 GHz的谐振频率下，系统的吸收率分别为96.77%、99.68%、99.68%、99.70%、98.03%、99.68%和99.98%。得益于旋转对称，吸收器对共极化和交叉极化入射波保持完全不敏感，在倾斜角度达90°时性能稳定。在目标频率下达到78 dB的最大屏蔽效率，确保对EM干扰的强大保护。紧凑的单晶电池（0.233λ × 0.233λ）具有接近零的介电常数、磁导率和单负折射率，进一步支持在最小的占地面积内有效吸收。为了验证物理行为，在ADS中开发了等效RLC电路模型，与CST仿真结果非常吻合。利用制造的样机和矢量网络分析仪的测量结果进行实验验证，证实了模拟结果和测量结果之间的强一致性。这项工作的新颖之处在于在旋转对称布局中集成了带有连续传输线的符号形谐振器，实现了宽带吸收、极化和角度不敏感，以及紧凑几何结构内的高屏蔽效率。这些特性使得该吸收器非常适合于Wi-Fi、5G、航空航天、国防雷达和隐身电磁屏蔽应用。

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引用次数: 0

Secure electric vehicle charging station demand forecasting under adversarial and false data injection attacks 对抗性和虚假数据注入攻击下的电动汽车充电站需求预测安全

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-04 DOI: 10.1016/j.jestch.2025.102203

Najmul Alam, M.A. Rahman, Md. Arafat Hossain, Md. Rashidul Islam

Forecasting the charging demand of electric vehicle charging stations (EVCSs) is critical for urban planning, resource allocation, policy development, and efficient grid management. However, reliance on sensor-collected data transmitted through various communication channels poses significant cybersecurity risks to forecasting models. This study evaluates the vulnerability of several commonly used forecasting models named random forest (RF), convolutional neural network (CNN), convolutional long short-term memory (ConvLSTM), and bidirectional convolutional long short-term memory (BiConvLSTM), under simulated cyber-attacks. Different attack scenarios, including fast gradient sign method (FGSM) and basic iterative method (BIM)-based adversarial attacks and scaling-based false data injection (FDI) attacks, are considered with varying attack volumes and perturbations. Metrics, such as root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE), are employed to assess and compare the accuracies of different models. Results indicate that forecasting models exhibit significant performance degradation under these cyber-attacks. As a countermeasure, adversarial training has been employed to mitigate the impact of such attacks and has proven to be highly effective. The experimental observations in this research elucidate the impact of cyber-attacks along with a defense mechanism to mitigate economic and technical risks to the EVCS, fostering the future development of accurate and cyber-resilient forecasting methodologies essential for advancing both academic and industrial domains of EVCS demand forecasting.

预测电动汽车充电站的充电需求对城市规划、资源配置、政策制定和有效的电网管理至关重要。然而，对通过各种通信渠道传输的传感器收集数据的依赖给预测模型带来了重大的网络安全风险。本研究评估了几种常用的预测模型随机森林（RF）、卷积神经网络（CNN）、卷积长短期记忆（ConvLSTM）和双向卷积长短期记忆（BiConvLSTM）在模拟网络攻击下的脆弱性。不同的攻击场景，包括基于快速梯度符号法（FGSM）和基于基本迭代法（BIM）的对抗性攻击和基于缩放的虚假数据注入（FDI）攻击，考虑了不同的攻击量和摄动。使用均方根误差（RMSE）、平均绝对误差（MAE）和平均绝对百分比误差（MAPE）等指标来评估和比较不同模型的准确性。结果表明，在这些网络攻击下，预测模型表现出明显的性能下降。作为一种对策，对抗性训练已被用于减轻此类攻击的影响，并已被证明是非常有效的。本研究的实验观察结果阐明了网络攻击的影响以及防御机制，以减轻EVCS的经济和技术风险，促进准确和网络弹性预测方法的未来发展，这对于推进EVCS需求预测的学术和工业领域至关重要。

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引用次数: 0

Design and analysis of a continuously linear polarization agile antenna using microwave liquid crystal technology 基于微波液晶技术的连续线极化捷变天线设计与分析

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-10-01 DOI: 10.1016/j.jestch.2025.102201

Onur Hamza Karabey

This paper presents the design and analysis of a continuously linear polarization-agile antenna based on Microwave Liquid Crystal (LC) technology. The proposed concept is specifically developed for Ku-band (e.g. 12 GHz) satellite communication applications, where systems typically operate with linear polarization and maintaining polarization alignment, referred to as skew angle adjustment, is critical for reliable on-the-move operation and for avoiding link loss. The antenna system incorporates a tunable feed network comprising two directional couplers and LC-based continuously tunable phase shifters. These feed a dual-fed microstrip patch antenna, enabling full-range linear polarization control over

\pm 18 0^{\circ}

by electronically adjusting the differential phase. The proposed tunable feed network is implemented using microwave LC technology to enable a fully passive architecture without requiring low-noise amplifiers. LC materials offer electrically tunable dielectric properties with inherently low dielectric loss, typically below 0.06 at frequencies beyond 10 GHz, and their loss tangent decreases with increasing frequency, making them particularly well-suited for Ku-band applications and beyond. In addition, LC materials benefit from a mature fabrication infrastructure originating from LC display manufacturing, allowing low-cost, large-area, and scalable production. Full-wave simulations at 12 GHz show that the system achieves a cross-polarization discrimination (XPD) better than 25 dB across the entire skew angle range. The LC-based phase shifters operate with only two bias voltages and provide 180° differential phase shift with an insertion loss below 2.3 dB, yielding a figure-of-merit of 80°/dB at 12 GHz. These results demonstrate the feasibility of the proposed design for low-loss, scalable, and reconfigurable antenna arrays in Ku-band and beyond satellite systems.

介绍了一种基于微波液晶技术的连续线性极化捷变天线的设计与分析。所提出的概念是专门为ku波段（例如12 GHz）卫星通信应用开发的，其中系统通常以线性极化运行，并且保持极化对准（称为倾斜角度调整）对于可靠的移动操作和避免链路丢失至关重要。天线系统包含一个可调谐馈电网络，包括两个定向耦合器和基于lc的连续可调谐移相器。这些天线馈送一个双馈微带贴片天线，通过电子调节差动相位，在±180°范围内实现线性极化控制。所提出的可调谐馈源网络采用微波LC技术实现，无需低噪声放大器即可实现全无源架构。LC材料具有电可调谐的介电特性，具有固有的低介电损耗，在10 GHz以上的频率下通常低于0.06，并且其损耗正切随频率的增加而降低，使其特别适合ku波段及更高波段的应用。此外，LC材料受益于源于LC显示器制造的成熟制造基础设施，允许低成本，大面积和可扩展的生产。12 GHz全波仿真结果表明，该系统在整个斜角范围内的交叉极化判别（XPD）优于25 dB。基于lc的移相器仅在两个偏置电压下工作，并提供180°差分移相，插入损耗低于2.3 dB，在12 GHz时产生80°/dB的性能因数。这些结果证明了所提出的低损耗、可扩展和可重构天线阵列在ku波段及以上卫星系统中的可行性。

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引用次数: 0

Handover management for UAV communication in 5G networks: A systematic literature review 5G网络下无人机通信的交接管理：系统文献综述

IF 5.4 2区工程技术 Q1 ENGINEERING, MULTIDISCIPLINARY

Engineering Science and Technology-An International Journal-Jestech

Pub Date : 2025-09-26 DOI: 10.1016/j.jestch.2025.102198

Azita Laily Yusof, Ahmad Zaki Aiman Abdul Rashid, Darmawaty Mohd Ali

Within the last ten years, UAVs has captured both the academia’s and industry players attention due to their capabilities to be utilized in multiple applications. One of the most prominent functionalities that UAVs provided for multiple applications is communication. Due to these functionalities, UAVs are seen as a major player in the 5G/6G cellular networks. Extending the connectivity and communication through multiple devices is the main goal of the 5G/6G networks. In this context, UAVs can either be deployed as relays that receive signals from BS and transmit them to the UE, or the UAVs can be utilized as a BS that flies (UAV-BS) and supplies 5G/6G communication to the UEs on the ground. However, there are many issues that arise with UAV communication networks when trying to provide signal coverage to users. One of the issues is when utilizing UAV as a BS, the signal coverage’s quality might not be up to par due to the UAV’s high mobility characteristics, which also leads to the frequent handover experienced by the users on the ground. Frequent handovers, or “ping-pong” handovers, are not acceptable and can instigate other problems that reduce the quality of the signal, such as packet delays, or losses of packets. Efficient handover management in drone communication is the solution to this problem, and, thus, it requires to be applied to the UAV networks to sustain connectivity that is reliable and stable. This paper studies the handover management for UAV communication in 5G networks using the systematic literature review (SLR) technique for its methodology. Multiple topics related to the handover scenario in the UAV networks are being highlighted in this paper, alongside studies related to machine learning (ML) usage in making handover decisions. A total of 90 research papers that relate to the handover in UAV networks and that were published from 2019 to 2024 were chosen. The results from our studies show that machine learning is able to provide handover decision that are more efficient and robust than traditional/conventional methods of making handover decisions. Finally, several discussions based on several themes and the limitations of the studies were held.

在过去的十年中，无人机由于其在多种应用中使用的能力而引起了学术界和工业界的关注。无人机为多种应用提供的最突出的功能之一是通信。由于这些功能，无人机被视为5G/6G蜂窝网络的主要参与者。通过多个设备扩展连接和通信是5G/6G网络的主要目标。在这种情况下，无人机可以作为接收来自BS的信号并将其传输到UE的中继器部署，或者无人机可以用作飞行（UAV-BS）并向地面UE提供5G/6G通信的BS。然而，当试图向用户提供信号覆盖时，UAV通信网络出现了许多问题。其中一个问题是，当使用无人机作为BS时，由于无人机的高机动性特性，信号覆盖质量可能达不到标准，这也导致地面用户频繁切换。频繁的切换或“乒乓”切换是不可接受的，并且会引发其他问题，降低信号质量，如数据包延迟或数据包丢失。有效的无人机通信切换管理是解决这一问题的方法，因此需要将其应用到无人机网络中，以保持可靠和稳定的连通性。本文采用系统文献回顾（SLR）技术对5G网络中无人机通信的切换管理进行了研究。本文强调了与无人机网络中切换场景相关的多个主题，以及与机器学习（ML）在切换决策中的使用相关的研究。选择2019年至2024年发表的90篇与无人机网络交接相关的研究论文。我们的研究结果表明，机器学习能够提供比传统/传统的切换决策方法更有效和健壮的切换决策。最后，根据几个主题和研究的局限性进行了几次讨论。

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引用次数: 0