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International Journal of Digital Earth 2019年第10期12卷 1118-1132页

作者： quang-thanh bui Manh Pham Van Nguyen Thi Thuy Hang Quoc-Huy Nguyen Nguyen Xuan Linh Pham Minh Hai Tran Anh Tuan Pham Van Cu Center for Applied Research in Remote sensing and GIS(CARGIS) VNU University of ScienceHa NoiViet Nam VNU University of Science Ha NoiViet Nam Vietnam Institute of Geodesy and Cartography Ha NoiViet Nam Ministry of Education and Training Ha NoiViet Nam

This study proposed a novel object-based hybrid classification model named GMNN that combines Grasshopper Optimization Algorithm(GOA)and the multiple-class Neural network(MNN)for urban pattern detection in Hanoi,*** bands of SPOT 7 image and derivable NDVI,NDWI were used to generate image segments with associated attributes by PCI Geomatics *** segments were classified into four urban surface types(namely water,impervious surface,vegetation and bare soil)by the proposed ***,three training and validation datasets of different sizes were used to verify the robustness of this *** all tests,the overall accuracies of the classification were approximately 87%,and the Area under Receiver Operating Characteristic curves for each land cover type was ***,the performance of this model was examined by comparing several statistical indicators with common benchmark *** results showed that GMNN out-performed established methods in all comparable *** results suggested that our hybrid model was successfully deployed in the study area and could be used as an alternative classification method for urban land cover *** a broader sense,classification methods will be enriched with the active and fast-growing contribution of metaheuristic algorithms.

关键词： Urban remote sensing object-based classification neural network grasshopper optimization algorithm

Marketing Strategies Evaluation and Selection for Supply Chain Management Under Uncertainty

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Computers, Materials & Continua 2022年第12期73卷 6535-6546页

作者： Ngo quang Trung Nguyen Van thanh Faculty of Commerce Van Lang UniversityHo Chi Minh City70000Vietnam

Sustainable marketing,often known as green marketing,has grown in popularity over the last two *** is currently putting pressure to encourage firms to become environmentally aware in multiple aspects like human and financial utilization,advertisement,and product *** types of companies are including many environmental campaigns into their own products to take advantage of the *** many scholars have addressed the relevance of green marketing as well as theory development,this study is unique in that it examines both techniques in a fuzzy *** integrated Fuzzy Multicriteria Decision Making Model(MCDM)of the analytical hierarchy process(AHP)and a Portuguese-acronymous MCDM method(TODIM)are used to select the best marketing strategy from five alternatives:(i)Green Design,(ii)Green Positioning,(iii)Green Pricing,(v)Green Packaging,and(iv)Green *** on criteria such as the scale of the green market,price parity,and the commitment of top *** for evaluating green marketing strategies was established in the study as contributions for decisionmakers in this field under unclarified *** research also a useful guideline for ranking alternatives in others industry.

关键词： Green marketing MCDM model sustainable marketing strategy

Atomistic simulation of free transverse vibration of graphene,hexagonal SiC, and BN nanosheets

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Acta Mechanica Sinica 2017年第1期33卷 132-147页

作者： Danh-Truong Nguyen Minh-Quy Le thanh-Lam bui Hai-Le bui School of Mechanical Engineering Hanoi University of Science and Technology Hanoi 10000 Vietnam International Institute for Computational Science and Engineering Hanoi University of Science and TechnologyHanoi 10000 Vietnam Faculty of Mechanical Engineering Hanoi University of Industry Hanoi 10000 Vietnam

Free transverse vibration of monolayer graphene, boron nitride (BN), and silicon carbide (SiC) sheets is investigated by using molecular dynamics finite element method. Eigenfrequencies and eigenmodes of these three sheets in rectangular shape are studied with different aspect ratios with respect to various boundary conditions. It is found that aspect ratios and boundary conditions affect in a similar way on natural frequencies of graphene, BN, and SiC sheets. Natural frequencies in all modes decrease with an increase of the sheet’s size. Graphene exhibits the highest natural frequencies, and SiC sheet possesses the lowest ones. Missing atoms have minor effects on natural frequencies in this study.

关键词： Atomistic simulation Hexagonal sheet Transverse vibration Molecular dynamics finite element method

A Simplified Approach of Open Boundary Conditions for the Smoothed Particle Hydrodynamics Method

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Computer Modeling in Engineering & Sciences 2021年第11期129卷 425-442页

作者： thanh Tien bui Yoshihisa Fujita Susumu Nakata Graduate School of Information Science and Engineering Ritsumeikan UniversityShiga525-8577Japan College of Information Science and Engineering Ritsumeikan UniversityShiga525-8577Japan

In this paper,we propose a simplified approach of open boundary conditions for particle-based fluid simulations using the weakly compressible smoothed-particle hydrodynamics(SPH)*** this scheme,the values of the inflow/outflow particles are calculated as fluid particles or imposed desired values to ensure the appropriate evolution of the flow field instead of using a renormalization process involving the fluid *** concentrate on handling the generation of new inflow particles using several simple approaches that contribute to the flow field *** advantages of theδ^(+).-SPH scheme,specifically the particle shifting technique,were successfully applied to correct the position,velocity,and pressure terms of the ***,unexpected errors were removed and tensile instabilities of the particles were *** proposed technique is validated for several benchmark test cases,and the tests show that the results match the reference solutions well.A viscous open-channel flow is used to demonstrate the stability of the flow field during the computational *** on this stability,we compress the computational domain to a lower resolution in a second test case while preserving the accuracy of the *** over a backward-facing step is used to highlight the challenges of inflow boundary conditions with prescribed or non-prescribed *** developed technique is well suited to the wall boundaries and the evolution of the flow *** results demonstrate the robustness and versatility of the proposed technique for a variety of simulations.

关键词： Fluid simulation smoothed particle hydrodynamics open boundaries

GLOBAL BOUND ON THE GRADIENT OF SOLUTIONS TO p-LAPLACE TYPE EQUATIONS WITH MIXED DATA

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Acta Mathematica Scientia 2024年第4期44卷 1394-1414页

作者： Minh-Phuong TRAN The-quang TRAN thanh-Nhan NGUYEN Applied Analysis Research Group Faculty of Mathematics and StatisticsTon Duc Thang UniversityHo Chi Minh CityVietnam Nguyen Huu Huan High School Thu Duc CityVietnam Group of Analysis and Applied Mathematics Department of MathematicsHo Chi Minh City University of EducationVietnam

In this paper,the study of gradient regularity for solutions of a class of elliptic problems of p-Laplace type is *** particular,we prove a global result concerning Lorentz-Morrey regularity of the non-homogeneous boundary data problem:-div((s^(2)+|▽u|^(2)p-2/2)▽u)=-div(|f|^(p-2)f)+g inΩ,u=h in■Ω,with the(sub-elliptic)degeneracy condition s∈[0,1]and with mixed data f∈L^(p)(Q;R^(n)),g∈Lp/(p-1)(Ω;R^(n))for p∈(1,n).This problem naturally arises in various applications such as dynamics of non-Newtonian fluid theory,electro-rheology,radiation of heat,plastic moulding and many *** on the idea of level-set inequality on fractional maximal distribution functions,it enables us to carry out a global regularity result of the solution via fractional maximal *** to the significance of M_(α)and its relation with Riesz potential,estimates via fractional maximal functions allow us to bound oscillations not only for solution but also its fractional derivatives of orderα.Our approach therefore has its own interest.

关键词： gradient estimates p-Laplace quasilinear elliptic equation fractional maximal operators Lorentz-Morrey spaces

Novel Soft ComputingModel for Predicting Blast-Induced Ground Vibration in Open-Pit Mines Based on the Bagging and Sibling of Extra Trees Models

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Computer Modeling in Engineering & Sciences 2023年第3期134卷 2227-2246页

作者： quang-Hieu Tran Hoang Nguyen Xuan-Nam bui Department of Surface Mining Mining FacultyHanoi University of Mining and GeologyHanoi100000Vietnam Innovations for Sustainable and Responsible Mining(ISRM)Research Group Hanoi University of Mining and GeologyHanoi100000Vietnam

This study considered and predicted blast-induced ground vibration(PPV)in open-pit mines using bagging and sibling techniques under the rigorous combination of machine learning ***,four machine learning algorithms,including support vector regression(SVR),extra trees(ExTree),K-nearest neighbors(KNN),and decision tree regression(DTR),were used as the base models for the purposes of combination and PPV initial *** bagging regressor(BA)was then applied to combine these base models with the efforts of variance reduction,overfitting elimination,and generating more robust predictive models,abbreviated as BA-ExTree,BAKNN,BA-SVR,and *** is emphasized that the ExTree model has not been considered for predicting blastinduced ground vibration before,and the bagging of ExTree is an innovation aiming to improve the accuracy of the inherently ExTree model,as *** addition,two empirical models(i.e.,USBM and Ambraseys)were also treated and compared with the bagging models to gain a comprehensive *** this aim,we collected 300 blasting events with different parameters at the Sin Quyen copper mine(Vietnam),and the produced PPV values were also *** were then compiled as the dataset to develop the PPV predictive *** results revealed that the bagging models provided better performance than the empirical models,except for the BA-DTR *** those,the BA-ExTree is the best model with the highest accuracy(i.e.,88.8%).Whereas,the empirical models only provided the accuracy from 73.6%–76%.The details of comparisons and assessments were also presented in this study.

关键词： Mine blasting blast-induced ground vibration environmentally friendly blasting peak particle velocity bagging extra trees

Mining fine-grained sequential travel patterns from social geo-tagged photos

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Frontiers of Computer Science 2018年第6期12卷 1255-1257页

作者： thanh-Hieu bui Seong-Bae PARK Institute of Research and Development Duy Tan UniversityDa Nang 550000Vietnam Department of Computer Science and Engineering Kyung Hee UniversityYongin 17104Korea

A huge amount of geo-tagged photos that contains broad knowledge about travel behaviors of human is generated and posted on social photo-sharing sites. In literature, many studies about mining travel patterns from geo-tagged social photos have been proposed. However, the existing studies lack of a comprehensive system to mine fine-grained travel patterns by utilizing extensions of sequential pattern mining. We consider the following questions for San Francisco City, CA, USA: 1) What are the popular travel routes for tourists if they have only four hours or eight hours for visiting? 2) Which POIs do international tourists prefer to visit after visiting Golden Gate Bridge? 3) Are there any differences in travel behavior between American tourists and international tourists, between male American tourists and female American tourists, between male international tourists and female international tourists? To address these questions, we define and implement a novel framework to mine fine-grained travel patterns from geo-tagged photos of a tourist destination.

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Occurrence of microcystins in water,sediment,and aquatic animals in Dau Tieng Reservoir,Vietnam

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Journal of Oceanology and Limnology 2024年第6期42卷 1751-1763页

作者： thanh Luu PHAM Manh Ha bui Tan Duc NGUYEN thanh Son DAO Faculty of Environment and Labour Safety Ton Duc Thang UniversityHo Chi Minh City 700000Vietnam Faculty of Environment Saigon UniversityHo Chi Minh City 700000Vietnam Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention and Guangdong Provincial Key Laboratory of Marine BiotechnologyShantou UniversityShantou 515063China Faculty of Environment and Natural Resources Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam Asian Center for Water Research(Centre Asiatique de Recherchesur l’Eau CARE)Ho Chi Minh City University of Technology(HCMUT)Vietnam National UniversityHo Chi Minh City 700000Vietnam

This study investigates the variations of microcystins(MCs)in water,cyanobacterial blooms,sediment,and aquatic organisms collected from the Dau Tieng Reservoir(DTR).*** liquid chromatography(HPLC)was employed to measure MC concentrations in various target *** indicate that Microcystis *** as the primary MC producer in the *** average concentrations of analyzed MCs in surface water ranged from 1.10 to 5.54μg/L,temporally and *** sediment,average concentrations varied from 0.15 to 1.13μg/g wet weight(WW)temporally and from 0.41 to 0.72μg/g WW *** were detected in different organs of fish species(Oreochromis *** Labiobarbus sp.)and in the entire soft tissues of bivalve(Corbicula sp.)and gastropod(Assiminea sp.).The highest observed MC concentration in July was 0.83±0.22μg/g WW in the intestines of fish Oreochromis *** presence of MCs in grass shrimp Palaemonetes *** observed solely in June,reaching a concentration of 0.28±0.19μg/g *** is the first report of MC accumulation in the grass shrimp Palaemonetes *** field *** the bivalve Corbicula sp.,the presence of analyzed MCs was consistent throughout the study period,except for March and September,with the highest concentrations in July at 0.77±0.1μg/g *** correlation analysis revealed significant positive correlations between MCs in water and sediment with MC concentrations in aquatic animals,indicating the potential transfer of MCs across different trophic *** estimated daily intake values for analyzed MCs indicate that fish collected from the DTR are considered safe for consumption,as long as only the edible organs,such as the muscle,are ***,bivalves or gastropods collected from the DTR are not safe for human *** study underscored the importance of monitoring MC accumulation in aquatic animals used as food to mitigate adverse effects on human health.

关键词： aquatic animal bioaccumulation cyanotoxin health risk toxic cyanobacteria

A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 146-156页

作者： Thong Duc Hong Minh quang Pham Son Cong Tran Lam quang Tran Truong thanh Nguyen Faculty of Transportation Engineering Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City(VNU-HCM) Ho Chi Minh City 700000Vietnam Industrial Maintenance Training Center Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been *** mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding *** simulation findings are compared to the analytical calculation results in the steady state,and both methods show good *** the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model ***,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting *** established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system *** is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

关键词： Dump truck Lifting mechanism Hydraulic MATLAB Simscape Kinetic dynamic analysis

Simulation of cohesive crack growth by a variable-node XFEM

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Frontiers of Structural and Civil Engineering 2020年第1期14卷 215-228页

作者： Weihua FANG Jiangfei WU Tiantang YU thanh-Tung NGUYEN Tinh Quoc bui Nanjing Automation Institute of Water Conservancy and Hydrology Nanjing 210012China Department of Engineering Mechanics Hohai UniversityNanjing 211100China Laboratory of Solid Structures University of LuxembourgLuxembourg L-1359Luxembourg Institute for Research and Development Duy Tan UniversityDa Nang City 550000Vietnam Department of Civil and Environmental Engineering Tokyo Institute of TechnologyTokyo 152-8552Japan

A new computational approach that combines the extended finite element method associated with variable-node elements and cohesive zone model is *** using a new enriched technique based on sign function,the proposed model using 4-node quadrilateral elements can eliminate the blending element *** also allows modeling the equal stresses at both sides of the crack in the crack-tip as assumed in the cohesive model,and is able to simulate the arbitrary crack-tip *** multiscale mesh technique associated with variable-node elements and the arc-length method further improve the efficiency of the developed *** performance and accuracy of the present approach are illustrated through numerical experiments considering both mode-I and mixed-mode fracture in concrete.

关键词： extended finite element method cohesive zone model sign function crack propagation