VLU REPOSITORY DATABASE
Aiming to become one of the most admired young universities in Asia, Van Lang University focuses on promoting scientific research activities. The Van Lang lecturer’s and student’s research results have given diverse sources of information to the internal and to the academic community.
VLU Repository Database provides many collections of resources: Bachelor’s Theses, Master’s Theses, Academic Papers, Conference Proceeding, VLU Projects.
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Publication"On the problem of the densest packing of spherical segments into a sphere Sobre o problema do empacotamento mais denso de segmentos esféricos em uma esfera"( 2023)"The paper considers a particular variant of the classical optimal packing problem when the container is a sphere, the packed elements are equal spherical caps, and the optimality criterion is to maximize their geodesic radius. At the same time, we deal with a special integral metric to determine the distance between points, which becomes Euclidean in the simplest case. We propose a heuristic numerical algorithm based on the construction of spherical Voronoi diagrams, which makes it possible to obtain a locally optimal solution to the problem under consideration. Numerical calculations show the operability and effectiveness of the proposed method and allow us to draw some conclusions about the properties of packings."
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PublicationFormation of pyramidal structures through mixing gold and platinum atoms: the AuxPty2+ clusters with x + y = 10†( 2023)The geometric and electronic structures of a small series of mixed gold and platinum AuxPty2+ clusters, with x + y = 10, were investigated using quantum chemical methods. A consistent tetrahedral pyramid structure emerges, displaying two patterns of structural growth by a notable critical point at y = 5. This affects the clusters' electron population, chemical bonding, and stability. For the Pt-doped Au clusters with y values from 2 to 5, the bonds enable Pt atoms to assemble into symmetric line, triangle, quadrangle, and tetragonal pyramidal Pty blocks, respectively. For the Au-doped Pt clusters, with larger values of y > 5, the structures are more relaxed and the d electrons of Pt atoms become delocalized over more centers, leading to lower symmetry structures. A certain aromaticity arising from delocalization of d electrons over the multi-center framework in the doped Pt clusters contributes to their stability, with Pt102+ at y = 10 exhibiting the highest stability. While the ground electronic state of the neutral platinum atom [Xe]. 4f145d96s1 leads to a triplet state (3D3), the total magnetic moments of AuxPty2+ are large increasing steadily from 0 to 10 μB and primarily located on Pt atoms, corresponding to the increase of the number of Pt atoms from 0 to 10 and significantly enhancing the magnetic moments. An admixture of both Au and Pt atoms thus emerges as an elegant way of keeping a small pyramidal structure but bringing in a high and controllable magnetic moment.
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PublicationA NURBS-based IGA using zig-zag plate theory for nonlinear passive/semi-active damping analysis of laminated FG-CNTRC plates( 2023)"In this article, a novel numerical approach based on electromechanical coupling isogeometric analysis employing a piecewise linear zig-zag function is proposed for modeling and analysis of smart constrained layer damping (SCLD) treatment in multilayer porous functionally graded graphene platelets-reinforced composite (PFG-GPRC) plates. The approach efficiently approximates the geometric, mechanical, and electric displacement fields by utilizing non-uniform rational B-splines (NURBS) basis functions. These basis functions are subsequently integrated with the zig-zag formulation to characterize the system dynamic and help handle both continuous/discontinuous material properties at all interfaces, as well as improve the effectiveness of global–local numerical solutions for the analysis of current structures. The multilayer PFG-GPRC plate model is designed to incorporate porous, uniformly, or non-uniformly distributed layers based on three different graphene platelet patterns. The analysis of the SCLD treatment encompasses an examination of the frequency response function of the damped structure under passive/hybrid mechanisms, taking into account"
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PublicationAn electromechanical coupling isogeometric approach using zig-zag function for modeling and smart damping control of multilayer PFG-GPRC plates( 2023)"In this article, a novel numerical approach based on electromechanical coupling isogeometric anal ysis employing a piecewise linear zig-zag function is proposed for modeling and analysis of smart constrained layer damping (SCLD) treatment in multilayer porous functionally graded graphene platelets-reinforced com posite (PFG-GPRC) plates. The approach efficiently approximates the geometric, mechanical, and electric displacement fields by utilizing non-uniform rational B-splines (NURBS) basis functions. These basis func tions are subsequently integrated with the zig-zag formulation to characterize the system dynamic and help handle both continuous/discontinuous material properties at all interfaces, as well as improve the effective ness of global–local numerical solutions for the analysis of current structures. The multilayer PFG-GPRC plate model is designed to incorporate porous, uniformly, or non-uniformly distributed layers based on three different graphene platelet patterns. The analysis of the SCLD treatment encompasses an examination of the frequency response function of the damped structure under passive/hybrid mechanisms, taking into account"
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PublicationMULTI-TASKING LEARNING FOR THE PROBLEM OF DETERMINING THE POSITION AND DIRECTION OF PERSON AT THE TIME( 2023)With many practical applications print human life today such as manufacturing surveillance cameras, analyzing and processing customer behavior, ..., the problem of face detection and head pose estimation on digital images is being noticed by many researchers. A large number of proposed deep learning models have state-of-the-art accuracies such as YOLO, SSD, and MTCNN, solving the problem of face detection or HopeNet, FSA-Net, and RankPmodelsodel used for head pose estimation problems.According to bigmany state-of-the-artmethods, the process of this task consists of 2 parts face detection to head pose estimation. These two steps are completely independent and do not share information with each other. This makes the model clear print setup but does not leverage most of the featured resources extracted in each model. In this thesis, we proposed the PoseMultitask model with the motivation to leverage the features extracted from the face detection model, sharing them with the head pose estimation branch to improve accuracy. Also, with the variety of data, the Euler angle domain representing the face is large, our model can predict results in the 360° Euler angle domain. Applying the multi-tasking learning method, the PoseMultitask model can simultaneously predict the position and direction of the human head. To increase the ability to predict the head direction of the model, we change the representation of the human face from the rom Euler angle to vectors from the Rotation matrix.
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PublicationThe Interconnected Arctic — UArctic Congress 2016( 2017)This open access book presents the most current research results and knowledge from five multidisciplinary themes: Vulnerability of Arctic Environments, Vulnerability of Arctic Societies, Local and Traditional Knowledge, Building Long-term Human Capacity, New Markets for the Arctic, including tourism and safety. The themes are those discussed at the first ever UArctic Congress Science Section, St. Petersburg, Russia, September 2016. The book looks at the Arctic from a holistic perspective; how the environment (both marine and terrestrial) and communities can adapt and manage the changes due to climate change. The chapters provide examples of the state-of-the-art research, bringing together both scientific and local knowledge to form a comprehensive and cohesive volume.
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PublicationHealth risk assessment of volatile organic compounds at daycare facilities( 2021)Children are particularly vulnerable to many classes of the volatile organic compounds (VOCs) detected in indoor environments. The negative health impacts associated with chronic and acute exposures of the VOCs might lead to health issues such as genetic damage, cancer, and disorder of nervous systems. In this study, 40 VOCs including aldehydes and ketones, aliphatic hydrocarbons, esters, aromatic hydrocarbons, cyclic terpenes, alcohols, and glycol ethers were identified and qualified in different locations at the University of Missouri (MU) Child Development Laboratory (CDL) in Columbia, Missouri. Our results suggested that the concentrations of the VOCs varied significantly among classrooms, hallways, and playground. The VOCs emitted from personal care and cleaning products had the highest indoor levels (2-ethylhexanol-1, 3-carene, homomenthyl salicylate with mean concentration of 5.15 µg/m3, 1.57 µg/m3, and 1.47 µg/m3, respectively). A cancer risk assessment was conducted, and none of the 95th percentile dose estimates exceeded the age-specific no significant risk levels (NSRL) in all classrooms. Dimensionless toxicity index scores were calculated for all VOCs using a novel web-based framework called Toxicological Prioritization Index (ToxPi), which integrates multiple sources of toxicity data. According to the method, homomenthyl salicylate, benzothiazole, 2-ethylhexyl salicylate, hexadecane, and tridecane exhibited diverse toxicity profiles and ranked as the five most toxic indoor VOCs. The findings of this study provide critical information for policy makers and early education professionals to mitigate the potentially negative health impacts of indoor VOCs in the childcare facilities.