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China Communications 2019年第3期16卷 92-102页

作者： Tan N.Nguyen Minh Tran thanh-Long Nguyen Miroslav Voznak Wireless Communications Research Group Faculty of Electrical and Electronics Engineering Ton Duc Thang University Optoelectronics Research Group Faculty of Electrical and Electronics Engineering Ton Duc Thang University Center for Information Technology Ho Chi Minh City University of Food Industry Faculty of Electrical Engineering and Computer Science VSB-Technical University of Ostrava

In this paper, the system performance of a decode-and-forward(DF) full-duplex(FD) adaptive relaying network over the Rician fading environment is proposed, analyzed and demonstrated. In the first stage, the system is presented with the energy harvesting and information transmission processes. After that, the analytical expressions of the achievable throughput, the outage probability, and symbol error ratio(SER) were proposed, analyzed and demonstrated. Finally, the analytical results are also demonstrated by Monte-Carlo simulation in comparison with the closed-form expressions in the influence of the key system parameters. The results show that the analytical and simulated results match for all possible parameter values.

关键词： relaying network throughput outage probability SER wireless energy harvesting(EH)

Chimera state in a network of nonlocally coupled impact oscillators

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2021年第3期22卷 235-244页

作者： Jerzy WOJEWODA Karthikeyan RAJAGOPAL Viet-thanh PHAM Fatemeh PARASTESH Tomasz KAPITANIAK Sajad JAFARI Division of Dynamics Lodz University of TechnologyLodz90-924Poland Nonlinear Systems and Applications Faculty of Electrical and Electronics EngineeringTon Duc Thang UniversityHo Chi Minh CityVietnam Biomedical Engineering Department Amirkabir University of TechnologyTehran15875-4413Iran Health Technology Research Institute Amirkabir University of TechnologyTehran15875-4413Iran

Chimera state is a peculiar spatiotemporal pattern,wherein the coherence and incoherence coexist in the network of coupled identical *** this paper,we study the chimera states in a network of impact oscillators with nonlocal *** investigate the effects of the coupling strength and the coupling range on the network *** results reveal the emergence of the chimera state for significantly small values of coupling strength,and higher coupling strength values lead to unbounded motions in the *** also study the network in the case of excitation *** observe that the coupling helps in the maintenance of an oscillatory motion with a lower amplitude in the failed oscillator.

关键词： Mechanical oscillators Impact oscillator Coupled network Nonlocal coupling Chimera state

An efficient improved Gradient Boosting for strain prediction in Near-Surface Mounted fiber-reinforced polymer strengthened reinforced concrete beam

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1148-1168页

作者： Abdelwahhab KHATIR Roberto CAPOZUCCA Samir KHATIR Erica MAGAGNINI Brahim BENAISSA thanh CUONG-LE Structural Section DICEA Polytechnic University of MarcheAncona 60131Italy Centre for Engineering Application&Technology Solutions Ho Chi Minh City Open UniversityHo Chi Minh City 70000Vietnam Design Engineering Laboratory Toyota Technological InstituteNagoya 468-8511Japan

The Near-Surface Mounted(NSM)strengthening technique has emerged as a promising alternative to traditional strengthening methods in recent *** the past two decades,researchers have extensively studied its potential,advantages,and applications,as well as related parameters,aiming at optimization of construction ***,there is still a need to explore further,both from a static perspective,which involves accounting for the nonconservation of the contact section resulting from the bond-slip effect between fiber-reinforced polymer(FRP)rods and resin and is typically neglected by existing analytical models,as well as from a dynamic standpoint,which involves studying the trends of vibration frequencies to understand the effects of various forms of damage and the efficiency of *** address this gap in knowledge,this research involves static and dynamic tests on simply supported reinforced concrete(RC)beams using rods of NSM carbon fiber reinforced polymer(CFRP)and glass fiber reinforced polymer(GFRP).The main objective is to examine the effects of various strengthening *** research conducts bending tests with loading cycles until failure,and it helps to define the behavior of beam specimens under various damage degrees,including concrete *** analysis by free vibration testing enables tracking of the effectiveness of the reinforcement at various damage levels at each stage of the loading *** addition,application of Particle Swarm Optimization(PSO)and Genetic Algorithm(GA)is proposed to optimize Gradient Boosting(GB)training performance for concrete strain prediction in NSM-FRP *** GB using Particle Swarm Optimization(GBPSO)and GB using Genetic Algorithm(GBGA)systems were trained using an experimental data set,where the input data was a static applied load and the output data was the consequent *** models of GBPSO and GBGA have been shown to provide highly accurate results for predicting *** model

关键词： NSM technique fiber-reinforced polymer rods static and dynamic analysis GB PSO GA finite element analysis

A Hybrid Deep Learning Approach for PM2.5 Concentration Prediction in Smart Environmental Monitoring

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Intelligent Automation & Soft Computing 2023年第6期36卷 3029-3041页

作者： Minh thanh Vo Anh HVo Huong Bui Tuong Le Faculty of Information Technology HUTECH UniversityHo Chi Minh CityVietnam Natural Language Processing and Knowledge Discovery Laboratory Faculty of Information TechnologyTon Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Computing Fundamentals FPT UniversityHo Chi Minh CityVietnam Laboratory for Artificial Intelligence Institute for Computational Science and Artificial IntelligenceVan Lang UniversityHo Chi Minh CityVietnam Faculty of Information Technology Van Lang UniversityHo Chi Minh CityVietnam

Nowadays,air pollution is a big environmental problem in develop-ing *** this problem,particulate matter 2.5(PM2.5)in the air is an air *** its concentration in the air is high in developing countries like Vietnam,it will harm everyone’s *** prediction of PM2.5 concentrations can help to make the correct decision in protecting the health of the *** study develops a hybrid deep learning approach named PM25-CBL model for PM2.5 concentration prediction in ho Chi Minh City,***,this study analyzes the effects of variables on PM2.5 concentrations in Air Quality HCMC *** variables that affect the results will be selected for PM2.5 concentration ***,an efficient PM25-CBL model that integrates a convolutional neural network(CNN)andBidirectionalLongShort-TermMemory(Bi-LSTM)*** model consists of three following modules:CNN,Bi-LSTM,and Fully connected ***,this study conducts the experiment to compare the performance of our approach and several state-of-the-art deep learning models for time series prediction such as LSTM,Bi-LSTM,the combination of CNN and LSTM(CNN-LSTM),and *** empirical results confirm that PM25-CBL model outperforms other methods for Air Quality HCMC dataset in terms of several metrics including Mean Squared Error(MSE),Root Mean Squared Error(RMSE),Mean Absolute Error(MAE),and Mean Absolute Percentage Error(MAPE).

关键词： Time series prediction PM2.5 concentration prediction CNN Bi-LSTM network

Free radical scavenging and anti-proliferative activities of avocado(Persea americana Mill.) seed extract

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Asian Pacific Journal of Tropical Biomedicine 2019年第3期9卷 91-97页

作者： thanh Sang Vo Phuong Uyen Le Dai Hung Ngo NTT Institute of Hi-Technology Nguyen Tat Thanh University Faculty of Natural Sciences Thu Dau Mot University

Objective: To investigate the chemical components and biological activities of avocado seed extract and fractions in order to determine the nutritional and pharmaceutical values of avocado seed. Methods: Various organic solvents were applied for extraction and fractionation of avocado seed. 1,1-diphenyl-2-picryl-hydrazyl, 2,2-azinobis-3-ethyl benzothiazoline-6-sulfonic acid, and DNA oxidation assays were applied for investigation of free radical scavenging activity. Nitric oxide production was measured by Griess reaction assay. Moreover, MTT assay was used to measure cancer cell growth inhibition. Results: The result indicated that the avocado seed contains(7.14 ± 0.40) g lipid/100 g,(1.67 ± 0.03) g protein/100 g,(54.0 ± 1.2) g carbohydrate/100 g, and(62.0 ± 2.3) mg gallic acid equivalent/g dried weight extract. Moreover, dichloromethane and ethyl acetate were revealed to be the highest free radical scavenging fractions with IC_(50) values of(48.0 ± 3.4) μg/mL(1,1-diphenyl-2-picryl-hydrazyl assay) and(22.0 ± 1.8) μg/mL(2,2-azinobis-3-ethyl benzothiazoline-6-sulfonic acid assay), respectively. Additionally, the avocado seed extract and fractions were able to protect against H_2O_2-induced DNA damage at the concentration of 100 μg/mL. On the other hand, the ethanol extract was effective in reducing nitric oxide production from lipopolysaccharide-stimulated RAW 264.7 macrophage cells without cytotoxic effect. Notably, the avocado seed significantly inhibited the proliferation of human lung A549 and human gastric BGC823 cancer cells at the concentration of 200 μg/mL, especially hexane(81 ± 3)% and dichloromethane(75 ± 2)% fractions. Conclusions: The results of the present study supported the avocado seed as potential by-product source for further development of health beneficial products.

关键词： Avocado seed By-product DPPH Nitric oxide Cancer cells

Novel Criteria for Exponential Stability of Linear Non-Autonomous Functional Differential Equations

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Journal of Systems Science & Complexity 2019年第2期32卷 479-495页

作者： PHAM HUU ANH Ngoc THAI BAO Tran CAO thanh Tinh NGUYEN DINH Huy Department of Mathematics Vietnam National University-HCMC International University Faculty of Information Systems Vietnam National University-HCMC University of Information Technology Department of Mathematics Vietnam National University-HCMC University of Information Technology Division of Applied Mathematics Faculty of Applied Sciences Vietnam National University-HCMC Ho Chi Minh city University of Technology

General linear non-autonomous functional differential equations are considered. Explicit criteria for exponential stability are given. Furthermore, the authors present an explicit robust stability bound for systems su... 详细信息

关键词： Exponential stability linear functional differential equations perturbation

Electrical Properties of CuO-Doped PZT-PZN-PMnN Piezoelectric Ceramics Sintered at Low Temperature

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Journal of Materials Science and Chemical Engineering 2014年第11期2卷 20-27页

作者： Phan Dinh Gio Le Dai Vuong ho Thi thanh hoa Department of Physics College of Sciences Hu&ecirc University Hu&ecirc Vietnam Faculty of Chemical and Environmental Engineering Hu&ecirc Industry College Hu&ecirc Vietnam

The 0.8Pb(Zr0.48Ti0.52)O3-0.125Pb(Zn1/3Nb2/3)O3-0.075Pb(Mn1/3Nb2/3)O3 (PZT-PZN-PMnN) + x wt% CuO piezoelectric ceramics, where x = 0.0, 0.05, 0.075, 0.10, 0.125, 0.150, and 0.175, have been fabricated by the conventional solid-state reaction method and the B-site Oxide mixing technique (BO). The effect of CuO on the sinterability, structure, and electrical properties of PZT-PZN-PMnN ceramics was systematically studied. The CuO addition significantly reduced the sintering temperature of the ceramics from 1150°C to 850°C. Experimental results showed that with the doping of CuO, all the ceramics could be well sintered and exhibit a dense, pure perovskite structure. The specimen containing 0.125 wt% CuO sintered at 850°C showed the good electrical properties: the density of 7.91 g/cm3;the electromechanical coupling factor, kp = 0.55 and kt = 0.46;the dielectric constant, ε = 1179;the dielectric loss (tand) of 0.006;the mechanical quality factor (Qm) of 1174;the piezoelectric constant (d31) of 112 pC/N.

关键词： Crystal Structure Dielectric Piezoelectric Constant Mechanical Quality Factor

New Results on H_(∞) Control for Nonlinear Conformable Fractional Order Systems

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Journal of Systems Science & Complexity 2021年第1期34卷 140-156页

作者： MAI Viet Thuan NGUYEN Thi Huyen Thu NGUYEN Huu Sau NGUYEN Thi thanh Huyen Department for Management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh CityVietnam Faculty of General Science Hanoi University of Natural Resources and EnvironmentHanoiVietnam Faculty of Fundamental Science Hanoi University of IndustryHa NoiVietnam Department of Mathematics and Informatics Thainguyen University of SciencesThainguyenVietnam

This paper deals with H_(∞) control problem for nonlinear conformable fractional order systems. The authors first derive new sufficient condition for exponential stability of nonlinear conformable fractional order systems based on Lyapunov-like function method for conformable fractional order systems and linear matrix inequalities(LMIs) approach. Then, by introducing a new concepts of H_(∞) control problem for nonlinear conformable fractional order systems, the authors study H_(∞) performance analysis and H_(∞) state feedback controller design problems for the considered systems. In terms of LMIs, a sufficient condition is proposed to ensure the nonlinear conformable fractional order systems are not only exponentially stable, but also satisfy H_(∞) performance γ. An explicit expression for state feedback controllers is also designed to make the closed-loop system is exponentially stable with H_∞performance γ. Finally, numerical examples are given to illustrate the validity and effectiveness of the proposed results.

关键词： Conformable fractional-order H_(∞)control problems H_(∞)performance analysis linear matrix inequalities nonlinear systems

Graphical method based on modified maximum force criterion to indicate forming limit curves of 22MnB5 boron steel sheets at elevated temperatures

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Journal of Iron and Steel Research International 2021年第8期28卷 1009-1018页

作者： thanh Luyen Quoc-Tuan Pham Thi-Bich Mac Tien-Long Banh Duc-Toan Nguyen Faculty of Mechanical Engineering Hungyen University of Technology and EducationHungyen 160000Vietnam Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 70000Vietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh City 70000Vietnam School of Mechanical Engineering Hanoi University of Science and TechnologyHanoi City 100000Vietnam

A new approach for predicting forming limit curves(FLCs)at elevated temperatures was proposed *** are often used to predict failure and determine the optimal forming parameters of automotive ***,a graphical method based on a modified maximum force criterion was applied to estimate the FLCs of 22MnB5 boron steel sheets at room temperature using various hardening ***,the predicted FLC data at room temperature were compared with corresponding data obtained from Nakazima's tests to obtain the best *** estimate the FLC at elevated temperatures,tensile tests were conducted at various temperatures to determine the ratios of equivalent fracture strains between the corresponding elevated temperatures and room *** at elevated temperatures could be established based on obtained ***,the predicted FLCs at elevated temperatures did not agree well with the corresponding FLC experimental data of Zhou et al.A new method was proposed herein to improve the prediction of FLCs at elevated *** FLC calculated at room tem-perature was utilized to predict the failure of Nakazima's samples via finite element *** on the simulation results at room temperature,the mathematical relationships between the equivalent ductile fracture strain versus stress triaxiality and strain ratio were established and then combined with ratios between elevated and room temperatures to calculate the FLCs at different *** predicted FLCs at elevated temperatures agree well with the corresponding experimental FLC data.

关键词： Forming limit curve Modified maximum force criterion Graphical method Hardening law Finite element method Boron steel sheet Elevated temperature

A fully automated framework for helicopter rotor blades design and analysis including aerodynamics,structure, and manufacturing

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Chinese Journal of Aeronautics 2016年第6期29卷 1602-1617页

作者： Ngoc Anh Vu Jae Woo Lee Tuan Phuong Nam Le Song thanh Thao Nguyen Division of Computational Mechatronics Institute for Computational Science Ton Duc Thang University Faculty of Electrical & Electronics Engineering Ton Duc Thang University Department of Aerospace Information Engineering Konkuk University Faculty of Mechanical Engineering Industrial University of Ho Chi Minh City Department of Aerospace Engineering Ho Chi Minh City University of Technology Vietnam National University-Ho Chi Minh City

This study describes an integrated framework in which basic aerospace engineering aspects(performance, aerodynamics, and structure) and practical aspects(configuration visualization and manufacturing) are coupled and considered in one fully automated design optimization of rotor blades. A number of codes are developed to robustly perform estimation of helicopter configuration from sizing, performance analysis, trim analysis, to rotor blades configuration representation. These codes are then integrated with a two-dimensional airfoil analysis tool to fully design rotor blades configuration including rotor planform and airfoil shape for optimal aerodynamics in both hover and forward flights. A modular structure design methodology is developed for realistic composite rotor blades with a sophisticated cross-sectional geometry. A D-spar cross-sectional structure is chosen as a baseline. The framework is able to analyze all realistic inner configurations including thicknesses of D-spar, skin, web, number and ply angles of layers of each composite part,and materials. A number of codes and commercial software(ANSYS, Gridgen, VABS, Pre VABS,etc.) are implemented to automate the structural analysis from aerodynamic data processing to sectional properties and stress analysis. An integrated model for manufacturing cost estimation ofcomposite rotor blades developed at the Aerodynamic Analysis and Design Laboratory(AADL),Aerospace Information Engineering Department, Konkuk University is integrated into the framework to provide a rapid and dynamic feedback to configuration design. The integration of three modules has constructed a framework where the size of a helicopter, aerodynamic performance analysis, structure analysis, and manufacturing cost estimation could be quickly investigated. All aspects of a rotor blade including planform, airfoil shape, and inner structure are considered in a multidisciplinary design optimization without an exception of critical configuration.

关键词： Design optimization Helicopter rotor blades Integrated framework Modular structure design methodology Perform estimation