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Frontiers of Structural and Civil Engineering 2024年第11期18卷 1752-1774页

作者： truong-thang nguyen Viet-Hung DANG Thanh-Tung PHAM Faculty of Building and Industrial Construction Hanoi University of Civil EngineeringHanoi 11600Vietnam Research Group of Development and application of advanced materials and modern technologies in construction Hanoi University of Civil EngineeringHanoi 11600Vietnam

Collecting and analyzing vibration signals from structures under time-varying excitations is a non-destructive structural health monitoring approach that can provide meaningful information about the structures’safety without interrupting their normal *** paper develops a novel framework using prompt engineering for seamlessly integrating users’domain knowledge about vibration signals with the advanced inference ability of well-trained large language models(LLMs)to accurately identify the actual states of *** proposed framework involves formulating collected data into a standardized form,utilizing various prompts to gain useful insights into the dynamic characteristics of vibration signals,and implementing an in-house program with the help of LLMs to perform damage *** advantages,as well as limitations,of the proposed method are qualitatively and quantitatively assessed through two realistic case studies from literature,demonstrating that the present method is a new way to quickly construct practical and reliable structural health monitoring applications without requiring advanced programming/mathematical skills or obscure specialized programs.

关键词： structural health monitoring vibration large language model signal processing prompt engineering

Non-Negative Adaptive Mechanism-Based Sliding Mode Control for Parallel Manipulators with Uncertainties

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Computers, Materials & Continua 2023年第2期74卷 2771-2787页

作者： Van-truong nguyen Department of Mechatronics Engineering Hanoi University of IndustryHanoi159999Vietnam

In this paper,a non-negative adaptive mechanism based on an adaptive nonsingular fast terminal sliding mode control strategy is proposed to have finite time and high-speed trajectory tracking for parallel manipulators with the existence of unknown bounded complex uncertainties and external *** proposed approach is a hybrid scheme of the online non-negative adaptive mechanism,tracking differentiator,and nonsingular fast terminal sliding mode control(NFTSMC).Based on the online non-negative adaptive mechanism,the proposed control can remove the assumption that the uncertainties and disturbances must be bounded for the NFTSMC *** proposed controller has several advantages such as simple structure,easy implementation,rapid response,chattering-free,high precision,robustness,singularity avoidance,and finite-time *** all control parameters are online updated via tracking differentiator and non-negative adaptive law,the tracking control performance at high-speed motions can be better in real-time requirement and disturbance rejection ***,simulation results validate the effectiveness of the proposed method.

关键词： Parallel manipulator uncertainties and disturbances nonsingular fast terminal sliding mode control non-negative adaptive mechanism tracking differentiator

Static analysis of corrugated panels using homogenization models and a cell-based smoothed mindlin plate element (CS-MIN3)

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 251-272页

作者： Nhan nguyen-MINH Nha TRAN-VAN thang BUI-XUAN Trung nguyen-THOI Faculty of Applied Science Bach Khoa University (BKU)Ho Chi Minh CityVietnam Faculty of Mathematics and Computer Science Ho Chi Minh City University of Science (HCMUS)Ho Chi Minh CityVietnam Department of Mathematics L ouisiana State UniversityBaton RougeLA 70803USA Division of Computational Mathematics and Engineering Institute of Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Due Thang UniversityHo Chi Minh CityVietnam

Homogenization is a promising approach to capture the behavior of complex structures like corrugated panels. It enables us to replace high-cost shell models with stiffness-equivalent orthotropic plate alternatives. Many homogenization models for corrugated panels of different shapes have been proposed. However, there is a lack of investigations for verifying their accuracy and reliability. In addition, in the recent trend of development of smoothed finite element methods, the cell-based smoothed three-node Mindlin plate element (CS-MIN3) based on the first-order shear deformation theory (FSDT) has been proposed and successfully applied to many analyses of plate and shell structures. Thus, this paper further extends the CS-MIN3 by integrating itself with homogenization models to give homogenization methods. In these methods, the equivalent extensional, bending, and transverse shear stiftriess components which constitute the equivalent orthotropic plate models are represented in explicit analytical expressions. Using the results of ANSYS and ABAQUS shell simulations as references, some numerical examples are conducted to verify the accuracy and reliability of the homogenization methods for static analyses of trapezoidally and sinusoidally corrugated panels.

关键词： homogenization corrugated panel asymptotic analysis smoothed finite element method (S-FEM) cell-based smoothed three-node Mindlin plate element (CS-MIN3)

ON BOUNDEDNESS PROPERTY OF SINGULAR INTEGRAL OPERATORS ASSOCIATED TO A SCHRODINGER OPERATOR IN A GENERALIZED MORREY SPACE AND APPLICATIONS

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Acta Mathematica Scientia 2020年第5期40卷 1171-1184页

作者： Xuan truong LE Thanh Nhan nguyen Ngoc Trong nguyen Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Mathematics and Statistics Ton Due Thang UniversityHo Chi Minh CityVietnam Department of Mathematics Ho Chi Minh City University of EducationHo Chi Minh CityVietnam Department of Primary Education Ho Chi Minh City University of EducationHo Chi Minh CityVietnam

In this paper,we provide the boundedness property of the Riesz transforms associated to the Schrodinger operator■=-Δ+V in a new weighted Morrey space which is the generalized version of many previous Morrey type *** additional potential V considered in this paper is a non-negative function satisfying the suitable reverse Holder's *** results are new and general in many cases of *** an application of the boundedness property of these singular integral operators,we obtain some regularity results of solutions to Schrodinger equations in the new Morrey space.

关键词： weighted Morrey spaces Schodinger operator riesz transforms Regularity estima tes

Effect of three tree species on UV weathering of wood flour-HDPE composites

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Journal of Forestry Research 2020年第3期31卷 1071-1079页

作者： Van Dinh nguyen Tat thang nguyen Aihong Zhang Jianxiu Hao Weihong Wang Key Laboratory of Biobased Material Science&Technology(Ministry of Education) Northeast Forestry UniversityHarbin 150040China

Eucalyptus urophylla, Acacia mangium, and Pinus caribaea are the primary species for the wood industry in Vietnam. Wood residues of these species were used to reinforce high-density polyethylene(HDPE) composites. The flexural or bending property, impact strength and surface color were evaluated after exposure to accelerated ultraviolet weathering up to 2000 h. The weathered surface was characterized by scanning electron microscopy(SEM) and Fourier transform infrared(FTIR) spectroscopy. The results indicate that A. mangium/HDPE composites had the lowest color change and least fading,and remained stable after 1500 h exposure. FTIR spectroscopy showed that the oxidation of the composites increased in parallel with duration of exposure by assessing the concentration of carbonyl groups on the surfaces. SEM showed that all three species reinforced composites exhibited similar severe cracks after 1000 h;however, at the end of the weathering test, E. urophylla and P. caribaea composites were more severely cracked than A. mangium composites. A. mangium also had the highest flexural strength, impact strength and crystallinity duringweathering. A. mangium is the most preferable among the three species to reinforce HDPE.

关键词： Eucalyptus urophylla Acacia mangium Pinus caribaea Polyethylene Weathering Color Mechanical property

Electromechanical admittance-based automatic damage assessment in plate structures via one-dimensional CNN-based deep learning models

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Frontiers of Structural and Civil Engineering 2024年第11期18卷 1730-1751页

作者： Thanh-Canh HUYNH Nhat-Duc HOANG Quang-Quang PHAM Gia Toai truong Thanh-truong nguyen Institute of Research and Development Duy Tan UniversityDa Nang 550000Vietnam Faculty of Civil Engineering Duy Tan UniversityDa Nang 550000Vietnam Bridge and Road Department Danang Architecture UniversityDa Nang 550000Vietnam Faculty of Civil Engineering and Technology Dong A UniversityDa Nang 550000Vietnam Industrial Maintenance Training Center Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam

The conventional admittance approach utilizing statistical evaluation metrics offers limited information about the damage location,especially when damage introduces nonlinearities in admittance *** study proposes a novel automated damage localization method for plate-like structures based on deep learning of raw admittance signals.A one-dimensional(1D)convolutional neural network(CNN)-based model is designed to automate processing of raw admittance response and prediction of damage probabilities across multiple locations in a monitored *** admittance data set is augmented with white noise to simulate realistic measurement *** K-fold cross-validation technique is employed for training and testing the *** experimental validation of the proposed method shows that the proposed method can accurately identify the state and damage location in the plate with an average accuracy of 98%.Comparing with established 1D CNN models reveals superior performance of the proposed method,with significantly lower testing *** proposed method exhibits the ability to directly handle raw electromechanical admittance responses and extract optimal features,overcoming limitations associated with traditional piezoelectric admittance *** eliminating the need for signal preprocessing,this method holds promise for real-time damage monitoring of plate structures.

关键词： convolutional neural network electromechanical admittance electromechanical impedance piezoelectric transducer damage localization plate structure deep learning structural health monitoring

Enhancing Fire Detection Performance Based on Fine-Tuned YOLOv10

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Computers, Materials & Continua 2024年第11期81卷 2281-2298页

作者： Trong Thua Huynh Hoang Thanh nguyen Du thang Phu Faculty of Information Technology 2 Posts and Telecommunications Institute of Technology(PTIT)Ho Chi Minh City700000Vietnam

In recent years,early detection and warning of fires have posed a significant challenge to environmental protection and human *** learning models such as Faster R-CNN(Faster Region based Convolutional Neural Network),YOLO(You Only Look Once),and their variants have demonstrated superiority in quickly detecting objects from images and videos,creating new opportunities to enhance automatic and efficient fire *** YOLO model,especially newer versions like YOLOv10,stands out for its fast processing capability,making it suitable for low-latency ***,when applied to real-world datasets,the accuracy of fire prediction is still not *** study improves the accuracy of YOLOv10 for real-time applications through model fine-tuning techniques and data *** core work of the research involves creating a diverse fire image dataset specifically suited for fire detection applications in buildings and factories,freezing the initial layers of the model to retain general features learned from the dataset by applying the Squeeze and Excitation attention mechanism and employing the Stochastic Gradient Descent(SGD)with a momentum optimization algorithm to enhance accuracy while ensuring real-time fire *** results demonstrate the effectiveness of the proposed fire prediction approach,where the YOLOv10 small model exhibits the best balance compared to other YOLO family models such as nano,medium,and ***,the study provides an experimental evaluation to highlight the effectiveness of model fine-tuning compared to the YOLOv10 baseline,YOLOv8 and Faster R-CNN based on two criteria:accuracy and prediction time.

关键词： Fire detection accuracy prediction time fine-tuning real-time YOLOv10 Faster R-CNN

Dry eye rate and its relationship with disease stage in patients with primary hypertension:a cross-sectional study in Vietnam

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International Journal of Ophthalmology(English edition) 2024年第4期17卷 653-658页

作者： Tran Tat thang Pham Hong Phuong nguyen Sa Huynh nguyen Trung Kien nguyenDuy Toan nguyen Thi Thu Ha Le Ha Khoa nguyen Huu Dung Thai Doan thang Le Viet thang Nghe An Eye Hospital Nghe An 43000Vietnam Nghe An Friendship General Hospital Nghe An 43000Vietnam Military Hospital 103 Ha Noi 100000Vietnam Vietnam Military Medical University Ha Noi 100000Vietnam Hanoi Medical University Ha Noi 100000Vietnam Bạch Mai Hospital Ha Noi 100000Vietnam TTH Vinh General Hospital Nghe An 100000Vietnam

AIM:To determine the dry eye(DE)rate and its relationship with disease stage in patients with primary ***:A cross-sectional study included 432 patients with primary hypertension(with an equal number of patients in each group:144 in stage Ⅰ,Ⅱ,and Ⅲ hypertension)and 144 healthy subjects as a control *** Ocular Surface Disease Index(OSDI)and Schirmer Ⅰ test without anesthetics were conducted on all 576 *** with OSDI scores<13 and Schirmer Ⅰ values equal to or under 10 mm were diagnosed with ***:The ratio of DE in hypertension patients was higher than in the control group(41.7%versus 18.8%;P<0.001).The proportion of patients with DE increased gradually according to the hypertension stage:27.1% in stage Ⅰ,40.3% in stage Ⅱ,and 57.6% in stage Ⅲ,P<***,duration of hypertension,plasma urea,creatinine,and high-sensitivity C-reactive protein(CRP-hs)levels in hypertension patients with DE were higher than those without DE,P<*** age,a long duration of hypertension,diabetes mellitus,elevated plasma creatinine,and CRP-hs levels were independent factors associated with DE in primary hypertension patients,P<***:DE is a common disorder associated with advanced age,a long duration of hypertension,diabetes mellitus,elevated plasma CRP-hs,and creatinine levels in patients with primary hypertension.

关键词： primary hypertension dry eye stage of hypertension plasma creatinine

Optimal Operation of Energy Hub Based Micro-energy Network with Integration of Renewables and Energy Storages

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Journal of Modern Power Systems and Clean Energy 2022年第1期10卷 100-108页

作者： Thanhtung Ha Ying Xue Kaidong Lin Yongjun Zhang Vu Van thang Thanhha nguyen Department of Electric Power Systems Thai Nguyen University of Technology(TNUT)Thai NguyenVietnam University of Birmingham BirminghamU.K School of Electric Power South China University of TechnologyGuangzhouChina Thai nguyen University Thai NguyenVietnam

This study proposes an optimized model of a micro-energy network(MEN)that includes electricity and natural gas with integrated solar,wind,and energy storage systems(ESSs).The proposed model is based on energy hubs(EHs)and it aims to minimize operation costs and greenhouse *** research is motivated by the increasing use of renewable energies and ESSs for secure energy supply while reducing operation costs and environment effects.A general algebraic modeling system(GAMS)is used to solve the optimal operation problem in the *** results demonstrate that an optimal MEN formed by multiple EHs can provide appropriate and flexible responses to fluctuations in electricity prices and adjustments between time periods and *** also yields significant reductions in operation costs and *** proposed model can contribute to future research by providing a more efficient network model(as compared with the traditional electricity supply system)to scale down the environmental and economic impacts of electricity storage and supply systems on MEN operation.

关键词： Micro-energy network(MEN) natural gas price electricity price energy hub(EH) renewables energy storage optimal operation

SVC bitstream adaptation in MPEG-21 multimedia framework

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第5期7卷 764-772页

作者： thang truong Cong KIM Young Suk RO Yong Man KANG Jungwon KIM Jae-Gon Department of Engineering Information and Communications UniversityDaejeon 305-732 Korea Department of Engineering Information and Communications University Daejeon 305-732 Korea Electronics and Telecommunications Research Institute Daejeon 305-732 Korea

Scalable video coding (SVC) is the most promising video format for applications of collaborative communication. MPEG-21 standard has newly emerged to enable the interoperability of multimedia delivery in heterogeneous environments. In this paper we study adaptation of SVC bitstream in the context of MPEG-21 multimedia framework. For interfacing SVC bit- stream with MPEG-21 based adaptation system, we propose three SVC specific adaptation operators. Based on our previous work with multidimensional video adaptation, we present an effective approach, using MPEG-21 DIA AdaptationQoS description tool, to model QoS control for SVC adaptation. Then we show how the operator values could be computed from that representation. For the actual adaptation at bitstream level, we propose a procedure to remove the unnecessary NAL units from an SVC bitstream. The result of this study enables QoS management of SVC streaming in an efficient and standardized manner.

关键词： Multidimensional video adaptation, Scalable video coding (SVC), MPEG-21 DIA (Digital Item Adaptation), QoS