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On the Multiplicity and the Cohen-Macaulayness of Fiber Cones of Graded Modules

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Algebra Colloquium 2021年第1期28卷 13-32页

作者： nguyen tien Manh Department of Mathematics Hung Vuong University Nguyen Tat Thanh StreetViet Tri CityPhu ThoVietnam

Let(A,m)be a Noetherian local ring with maximal ideal m,I an ideal of A,J an m-primary ideal of A,N a finitely generated A-module,S=■n≥0 Sn a finitely generated standard graded algebra over A and M=■n≥0 Mn a finitely generated graded *** characterize the multiplicity and the Cohen-Macaulayness of the fiber cone F(M)=■n≥0 Mn/JM_(n).As an application,we obtain some results on the multiplicity and the Cohen--Macaulayness of the fiber cone■n≥0 I^(n)N/JI^(n)N.

关键词： (FC)-sequence filter-regular sequence multiplicity Cohen-Macaulay fiber cone

ITÔDIFFERENTIAL REPRESENTATION OF SINGULAR STOCHASTIC VOLTERRA INTEGRAL EQUATIONS

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Acta Mathematica Scientia 2020年第6期40卷 1989-2000页

作者： nguyen tien DUNG Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh CityVietnam

In this paper we obtain an Itôdifferential representation for a class of singular stochastic Volterra integral *** an application,we investigate the rate of convergence in the small time central limit theorem for the ... 详细信息

关键词： stochastic integral equation Itôformula central limit theorem

ASYMPTOTIC BEHAVIOR OF LINEAR ADVANCED DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2015年第3期35卷 610-618页

作者： nguyen tien DUNG Department of Mathematics FPT University 8 Ton That ThuyetMy DinhTu LiemHanoiVietNam

In this article, we consider a general class of linear advanced differential equa- tions, and obtain explicitly sufficient conditions of convergence and exponential convergence to zero. A necessary condition is provid... 详细信息

关键词： Advanced differential equations asymptotic behaviors fixed points

Asymptotic Expansions of Backward Equations for Two-time-scale Markov Chains in Continuous Time

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Acta Mathematicae Applicatae Sinica 2009年第3期25卷 457-476页

作者： Dung tien nguyen Department of Mathematics Wayne State University

This work develops asymptotic expansions for solutions of systems of backward equations of time- inhomogeneous Maxkov chains in continuous time. Owing to the rapid progress in technology and the increasing complexity in modeling, the underlying Maxkov chains often have large state spaces, which make the computa- tional tasks ihfeasible. To reduce the complexity, two-time-scale formulations are used. By introducing a small parameter ε〉 0 and using suitable decomposition and aggregation procedures, it is formulated as a singular perturbation problem. Both Markov chains having recurrent states only and Maxkov chains including also tran- sient states are treated. Under certain weak irreducibility and smoothness conditions of the generators, the desired asymptotic expansions axe constructed. Then error bounds are obtained.

关键词： Markov chain backward equation two-time scale asymptotic expansion

Development of an automatic and knowledge-infused framework for structural health monitoring based on prompt engineering

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FRONTIERS OF STRUCTURAL AND CIVIL ENGINEERING 2024年第11期18卷 1752-1774页

作者： nguyen, Truong-thang Dang, Viet-Hung Pham, Thanh-Tung Hanoi Univ Civil Engn Fac Bldg & Ind Construct Hanoi 11600 Vietnam Hanoi Univ Civil Engn Res Grp Dev & applicat Adv Mat & Modern Technol Co Hanoi 11600 Vietnam

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 operations. This 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 structures. The 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 detection. The 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

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)

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

Tungsten-based nanocatalysts with different structures for visible light responsive photocatalytic degradation of bisphenol A

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Journal of Environmental Sciences 2024年第5期139卷 569-588页

作者： Hai Bang Truong Thi Thu Loan Doan nguyen tien Hoang nguyen Van Tam Minh Kim nguyen Le Gia Trung Jin Seog Gwag nguyen tien Tran Optical Materials Research Group Science and Technology Advanced InstituteVan Lang UniversityHo Chi Minh CityViet Nam Faculty of Applied Technology School of TechnologyVan Lang UniversityHo Chi Minh CityViet Nam The University of Da Nang University of Science and Technology54 Nguyen Luong BangDa NangViet Nam The University of Da Nang University of Science and Education459 Ton Duc Thang St.Lien ChieuDa Nang 550000Viet Nam Institute of Veterinary Science and Technology 31ha zoneTrau QuyGia LamHa Noi 12400Viet Nam Department of Physics Yeungnam UniversityGyeongsanGyeongbuk 38541Republic of Korea Center for Advanced Chemistry Institute of Research and DevelopmentDuy Tan University03 Quang TrungDa Nang 550000Viet Nam Faculty of Natural Sciences Duy Tan University03 Quang TrungDa Nang 550000Viet Nam

Environmental pollution,such as water contamination,is a critical issue that must be absolutely ***,three different morphologies of tungsten-based photocatalysts(WO_(3)nanorods,WO_(3)/WS_(2)nanobricks,WO_(3)/WS_(2)nanorods)are made using a simple hydrothermal method by changing the solvents(H_(2)O,DMF,aqueous HCl solution).The as-prepared nanocatalysts have excellent thermal stability,large porosity,and high *** results show all materials have good photocatalytic activity in aqueous media,with WO_(3)/WS_(2)nanorods(NRs)having the best activity in the photodegradation of bisphenol A(BPA)under visible-light *** may originate from increased migration of charge carriers and effective prevention of electron–hole recombination in WO_(3)/WS_(2)NRs,whereby this photocatalyst is able to generate more reactive·OH and·O_(2)^(–)species,leading to greater photocatalytic *** 99.6% of BPA is photodegraded within 60 min when using 1.5 g/L WO_(3)/WS_(2)NRs and 5.0 mg/L BPA at pH ***,the optimal conditions(pH,catalyst dosage,initial BPA concentration)for WO_(3)/WS_(2)NRs are also elaborately *** rod-like heterostructures are expressed as potential catalysts with excellent photostability,efficient reusability,and highly active effectivity in different types of *** particular,the removal efficiency of BPA by WO_(3)/WS_(2)NRs reduces by only 1.5% after five recycling runs and even reaches 89.1%in contaminated lake *** study provides promising insights for the nearly complete removal of BPA from wastewater or different water resources,which is advantageous to various applications in environmental remediation.

关键词： Photodegradation Bisphenol A Tungsten-based nanocatalyst Structure Nanorod

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