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Nguyen Van Hieu

Publications and source records attributed to Nguyen Van Hieu.

5 recordsLinked to original sources

Automatic Plant Image Identification of Vietnamese species using Deep Learning Models

It is complicated to distinguish among thousands of plant species in the natural ecosystem, and many efforts have been investigated to address the issue. In Vietnam, the task of identifying one from 12,000 species requires specialized experts in flora management, with thorough training skills and in-depth knowledge. Therefore, with the advance of machine learning, automatic plant identification systems have been proposed to benefit various stakeholders, including botanists, pharmaceutical laboratories, taxonomists, forestry services, and organizations. The concept has fueled an interest in research and application from global researchers and engineers in both fields of machine learning and computer vision. In this paper, the Vietnamese plant image dataset was collected from an online encyclopedia of Vietnamese organisms, together with the Encyclopedia of Life, to generate a total of 28,046 environmental images of 109 plant species in Vietnam. A comparative evaluation of four deep convolutional feature extraction models, which are MobileNetV2, VGG16, ResnetV2, and Inception Resnet V2, is presented. Those models have been tested on the Support Vector Machine (SVM) classifier to experiment with the purpose of plant image identification. The proposed models achieve promising recognition rates, and MobilenetV2 attained the highest with 83.9%. This result demonstrates that machine learning models are potential for plant species identification in the natural environment, and future works need to examine proposing higher accuracy systems on a larger dataset to meet the current application demand.

cs.CV

Quantum Theory of Electron Transport Through Single-Level Quantum Dot

A new approach in the quantum theory of few-electron nanoelectronic devices -- the S-matrix approach -- is presented in a simple example: a single-electron transistor consisting of a single-level quantum dot connected with two metallic leads through the corresponding potential barriers. The electron transport through the quantum dot due to the electron tunneling between the dot and the leads is studied. The strong Coulomb repulsion between the electrons in the dot is taken into account exactly, while the tunneling between the dot and the leads, considered as a small perturbation, is studied by means of the perturbation theory. For summing up the infinite perturbation theory series we apply the Green function technique and the Heisenberg equation of motion of the electron annihilation and creation operators. The matrix elements of the transition processes include both the direct and crossing terms, so that there is no need to use the non-crossing approximation (NCA). The explicit expression of the electron transport current is derived.

hep-ph

Functional Integral Approach in the Theory of Color Superconductivity

In this series of lectures we present the functional integral method for studying the superconducting pairing of quarks with the formation of the diquarks as well as the quark-antiquark pairing in dense QCD. The dynamical equations for the superconducting order parameters are the nonlinear integral equations for the composite quantum fields describing the quark-quark or quark-antiquark systems. These composite fields are the bi-local fields if the pairing is generated by the gluon exchange while for the instanton induced pairing interactions they are the local ones. The expressions of the free energy densities are derived. The binding of three quarks is also discussed.

hep-ph

Functional Integral Method in Quantum Theory of Composite Particles and Quasiparticles

In this series of lectures we present the universal method based on the use of the functional integrals to derive the bound state equations for different two-body systems in elementary particle physics as well as in condensed matter theory: the relativistic Nambu-Jona-Lasinio equation and the relativistic Bethe-Salpeter equation in elementary particle physics, the Bethe-Salpeter equation for the bipolaritons. The bound state equation for the three-body systems is also established.

hep-ph

Functional Integral Method in the Theory of Color Superconductivity

We propose to study the superconducting pairing of quarks with the formation of the diquarks as well as the quark-antiquark pairing in QCD by means of the functional integral technique. The dynamical equations for the superconducting order parameters are the nonlinear integral equations for the composite quantum fields describing the quark-quark or quark-antiquark systems. These composite fields are the bi-local fields if the pairing is generated by the gluon exchange while for the instanton induced pairing interactions they are the local ones. The expressions of the free energy densities are derived. The binding of three quarks is also discussed.

hep-ph