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On the derivation of the entropy of ideal quantum gases confined in a three-dimensional harmonic potential

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Communications in Theoretical Physics 2020年第4期72卷 106-111页

作者： Le Tri Dat Vinh N T pham Laboratory of Applied Physics Advanced Institute of Materials ScienceTon Duc Thang UniversityHo Chi Minh City 756636Vietnam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh City 756636Vietnam Ho Chi Minh City University of Education Ho Chi Minh City 748342Vietnam

In this work,the entropy functions of ideal quantum gases in a three-dimensional harmonic trap are analytically calculated using temperature as an explicit ***,the applicability of the analytical formulas is validated by comparison with the numerical *** results illustrate that the obtained functions could be applied for the whole temperature regime with a maximum relative deviation of less than 7.5%in the vicinity of the critical temperature Tcin the case of Bose ***,for Fermi gases,although the analytical formula fits well at very low-and high-temperature regimes,it cannot be applied at temperature in the range[0.3-0.5]T_F,where T_F is the Fermi *** addition,the consistency between our formulas and classical ones at significantly high temperatures is also discussed.

关键词： thermodynamic properties entropy 3D harmonic trap ideal quantum gases

Thermal Performance Prediction in the Air Gap of a Rotor-Stator Configuration: Effects of Numerical Models

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Journal of Thermal Science 2020年第1期29卷 206-218页

作者： DANG Dinh-Dong pham Xuan-Tan NGUYEN Chi-Cong Department of Mechanical Engineering École de technologie supérieureMontrealQCCanada Hydro-Québec’s research institute VarennesQCCanada

This study is dedicated to a numerical investigation of convective heat transfer on the rotor surfaces of a rotor-stator configuration that is typically found in large *** computational fluid dynamics calculations with two turbulence modelling approaches are used to predict the flow structure and heat transfer in the air gap of the rotor-stator *** steady state mixing plane approach is employed at the interface to couple the rotor and stator *** show that the location of mixing plane interface in the air gap plays an important role in the prediction of heat transfer on the pole ***,it is indicated that the prediction of temperature distribution on the pole face is greatly affected by the turbulence models ***,through a comparison between the pure convective and conjugate heat transfer methodologies,it is shown that the inclusion of solid domain into the numerical model significantly improves the thermal prediction of the solid components of the machine.

关键词： hydro-generators electrical cooling mixing plane windage loss conjugate heat transfer

An improved CRNN for Vietnamese Identity Card Information Recognition

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Computer Systems Science & Engineering 2022年第2期40卷 539-555页

作者： Trinh Tan Dat Le Tran Anh Dang Nguyen Nhat Truong pham Cung Le Thien Vu Vu Ngoc Thanh Sang pham Thi Vuong pham The Bao Information Science Faculty Sai Gon UniversityHCM City700000Vietnam Faculty of Electrical&Electronics Engineering University of TechnologyHCM City700000Vietnam

This paper proposes an enhancement of an automatic text recognition system for extracting information from the front side of the Vietnamese citizen identity(CID)***,we apply Mask-RCNN to segment and align the CID card from the ***,we present two approaches to detect the CID card’s text lines using traditional image processing techniques compared to the EAST ***,we introduce a new end-to-end Convolutional Recurrent Neural Network(CRNN)model based on a combination of Connectionist Temporal Classification(CTC)and attention mechanism for Vietnamese text recognition by jointly train the CTC and attention objective functions *** length of the CTC’s output label sequence is applied to the attention-based decoder prediction to make the final label *** process helps to decrease irregular alignments and speed up the label sequence estimation during training and inference,instead of only relying on a data-driven attention-based encoder-decoder to estimate the label sequence in long *** may directly learn the proposed model from a sequence of words without detailed *** evaluate the proposed system using a real collected Vietnamese CID card dataset and find that our method provides a 4.28%in WER and outperforms the common techniques.

关键词： Vietnamese text recognition OCR CRNN BLSTM attention mechanism joint CTC-Attention

Vietnamese State Budget Accounting With the Relationships Between the State Budget Law and International Public Sector Accounting Standards （IPSAS）＊ pham Quang Huy University of Economics, Ho Chi Minh City, Vietnam

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Journal of Modern Accounting and Auditing 2013年第9期9卷 1194-1203页

作者： pham Quang Huy University of Economics Ho Chi Minh City Vietnam

For a long time, Vietnam has modifications in all aspects in the society. For many years, Vietnam has improved features in administrative works as well as in different areas, such as public administration, finance, and accounting In the accounting content, budget accounting is an important thing which is worth noting. However, along with the achievements, Vietnam is also facing a number of limitations to be overcome for ensuring transparency in the state budget. Since then, the main purpose of the article is to provide a general picture of budget accounting in Vietnam and what has not been done through finding the relationships with budget regulations and international public sector accounting. The results showed that Vietnam will transform and issue the new law on budget and build up a new model for controlling information published by data accounting system in the future.

关键词： state budget public sector budget law international standards international public sector accountingstandards (IPSAS)

Linear quadratic optimal control of conditional McKean-Vlasov equation with random coefficients and applications

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Probability, Uncertainty and Quantitative Risk 2016年第1期1卷 252-277页

作者： Huyen pham Laboratoire de Probabilites et Mod´eles Al`eatoires CNRSUMR 7599Universite Paris DiderotParisFrance CREST-ENSAE ParisFrance

We consider the optimal control problem for a linear conditional McKeanVlasov equation with quadratic cost *** coefficients of the system and the weighting matrices in the cost functional are allowed to be adapted processes with respect to the common noise *** closed-loop strategies are introduced,and following the dynamic programming approach in(pham and Wei,Dynamic programming for optimal control of stochastic McKean-Vlasov dynamics,2016),we solve the problem and characterize time-consistent optimal control by means of a system of decoupled backward stochastic Riccati differential *** present several financial applications with explicit solutions,and revisit,in particular,optimal tracking problems with price impact,and the conditional mean-variance portfolio selection in an incomplete market model.

关键词： Stochastic McKean-Vlasov SDEs Random coefficients Linear quadratic optimal control Dynamic programming Riccati equation Backward stochastic differential equation

Damage detection of a thin plate using modal curvature via macrostrain measurement

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 409-424页

作者： Ting Yu Hsu Yi Cheng Shih Quang-Vinh pham Department of Civil and Construction Engineering Taiwan University of Science and Technology Chung-Shan Institute of Science and Technology

Plate structures are employed as important structural components in many engineering applications. Hence, assessing the structural conditions of in-service plate structures is critical to monitoring global structural health. Modal curvature-based damage detection techniques have recently garnered considerable attention from the research community, and have become a promising vibration-based structural health monitoring solution. However, computing errors arise when calculating modal curvatures from lateral mode shapes, which result from unavoidable measurement errors in the mode shapes as identified from lateral vibration signals; this makes curvature-based algorithms that use a lateral measurement only theoretically feasible, but practically infeasible. Therefore, in this study, long-gauge fiber Bragg grating strain sensors are employed to obtain a modal curvature without a numerical differentiation procedure in order to circumvent the computing errors. Several damage indices based on modal curvatures that were developed to locate beam damage are employed. Both numerical and experimental studies are performed to validate the proposed approach. However, although previous studies have reported relative success with the application of these damage indices on a simple beam, only one damage index demonstrated the capability to locate damage when the stiffness of the local region changed near the sensor.

关键词： macro strain long gauge modal curvature plate damage detection

Spectral properties of the surface reflectance of the northern polar region of Mercury

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Research in Astronomy and Astrophysics 2020年第3期20卷 92-107页

作者： Nguyen Bich Ngoc Nicolas Bott pham Ngoc Diep Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18 Hoang Quoc VietCau GiayHanoiVietnam Laboratoire d'Etudes Spatiales et d' Instrumentation en Astrophysique l'Observatoire de Paris5 place Jules Janssen 92195 MeudonFrance

We analyze MESSENGER reflectance measurements covering the northern polar region of Mercury,the least studied region of the northern mercurian *** use observations from the Mercury Dual Imaging System Wide-Angle Camera(MDIS/WAC)and the Mercury Atmospheric and Surface Composition Spectrometer(MASCS/VIRS)to study the spectral dependence of the surface *** results obtained from the observations made by both instruments are remarkably *** find that a second degree polynomial description of the measured reflectance spectra gives very good fits to the data and that the information that they carry can best be characterized by two parameters,the mean reflectance and the mean relative spectral slope,averaged over the explored range of *** properties of the four main types of terrains known to form Mercury’s regolith in the northern region,smooth plains(SPs),heavily cratered terrain(HCT),fresh ejecta/materials and red pitted ground(RPG),are examined in terms of these two *** results are compared,and found consistent with those obtained by earlier studies in spite of difficulties met in obtaining accurate reflectance measurements under the large incidence angle condition characteristic of polar *** results will help with the preparation of the BepiColombo mission and with supporting its observational strategy.

关键词： planets and satellites terrestrial planets-planets and satellites surfaces-techniques spectroscopic

Design and Manufacture an Elastic Neutron Scattering Spectrometer at the Dalat Nuclear Reactor

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Journal of Analytical Sciences, Methods and Instrumentation 2021年第3期11卷 23-28页

作者： Dang Hong Ngoc Quy pham Ngoc Son Phan Bao quoc Hieu Trinh Van Cuong Nuclear Research Institute Dalat Lam Dong Vietnam

The objective of this study is to design an elastic neutron scattering system according to the angle with a sample using thermal neutron beam at the Dalat Nuclear Reactor (DNR). The system is used for research and training in the field of material structure analysis by neutron scattering and diffraction techniques. It is designed on the basis of inheriting the neutron measurement spectrometer systems at the DNR and the scattered neutron measurement systems in the world. The measuring system, which was installed at the horizontal channel 4 of the DNR, consists of 5-helium-3 detectors and a fully electronic system to record the scatter counts and a mechanical system with the possibility of rotating at 15˚-75˚ angles. The constructed system is tested for evaluation of the accuracy, stability and reliability of the mechanical and electronic systems of moving detectors by angles.

关键词： Neutron Scattering Small-Angle Neutron Scattering (SANS) Elastic Neu-tron Cross Section

On Types of Isolated KKT Points in Polynomial Optimization

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Journal of Systems Science & Complexity 2023年第5期36卷 2186-2213页

作者： GUO Feng JIAO Liguo KIM Do Sang pham Tien-Son School of Mathematical Sciences Dalian University of TechnologyDalian 116024China Academy for Advanced Interdisciplinary Studies Northeast Normal UniversityChangchun 130024China Department of Applied Mathematics Pukyong National UniversityBusan 48513South Korea Department of Mathematics Dalat UniversityDalat 96300Vietnam.

Let f be a real polynomial function with n variables and S be a basic closed semialgebraic set in R^(n).In this paper,the authors are interested in the problem of identifying the type(local minimizer,maximizer or not extremum point)of a given isolated KKT point x^(*)of f over *** this end,the authors investigate some properties of the tangency variety of f on S at x^(*),by which the authors introduce the definition of faithful radius of f over S at x^(*).Then,the authors show that the type of x^(*)can be determined by the global extrema of f over the intersection of S and the Euclidean ball centered at x^(*)with a faithful ***,the authors propose an algorithm involving algebraic computations to compute a faithful radius of x*and determine its type.

关键词： Faithful radii KKT points polynomial functions tangency varieties types