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NGOC, Bui Hoang Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.5
Tax is the main revenue of Government, so fighting tax evasion and sustainable growth have been the primary macroeconomic goals being pursued by every developing country, Vietnam included. The existence and development of the shadow economic sector are synonymous with the national budget losing out. In Vietnam, foreign direct investment projects do not promote economic growth and is also a sector that gives way to tax evasion.The purpose of this study is to investigate the impact of foreign direct investment, the quality of the informal institution on the size of the shadow economy in Vietnam, during the period 1991-2015. By applying the Autoregressive Distributed Lag approach and Toda and Yamamoto test, we found evidence to conclude that the quality of the informal institution harms the size of the shadow economy. The results of the causality test show that there is a unidirectional causality running from the shadow economy and the quality of the informal institution to foreign direct investment attraction in Vietnam. Political solutions need to be implemented carefully to counter the harmful effects of the shadow economy. Policymakers should adopt several economic policies to improve the 'human capital' and drive the shadow economy into the formal economy.
NGOC, Bui Hoang Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.2
Low inflation and sustainable growth have been the major macroeconomic goals being pursued by every developing country, Vietnam inclusive. The effect of inflation on economic growth has been intensively analyzed by a variety of studies, but the empirical evidence more often than not remains controversial and ambiguous. One common hypothesis of previous studies is that they have assumed that the effect of inflation on growth is symmetric. The main purpose of this study is to investigate the asymmetric effect of inflation and money supply on economic growth using the Nonlinear Autoregressive Distributed Lag approach introduced by Shin, Byungchul, and Greenwood-nimmo (2013) for Vietnam over the period 1990-2017. Empirical results provide evidence that the effects of inflation on economic growth are negative and asymmetric in the long run. The impact of money supply on growth is positive in both the short-run and long-run. Accordingly, the impact of the increase in the inflation rate is bigger than the decreasing in the long-run. This different impact is significant and high inflation will destruct economic activities. As a result, the study provides empirical evidence for the authorities to plan monetary policies and control the rate of inflation to achieve sustainable economic development in the long-run.
Human Detection On The Beach Using Drone Images For Safety Warning System
Nam Anh Bui,Ngoc Dung Bui,Nguyen Hanh Bui,Nguyen Hoang Bui,Kien Truc Le,Quang Tuyen Vu 한국차세대컴퓨팅학회 2023 한국차세대컴퓨팅학회 학술대회 Vol.2023 No.12
Integrating unmanned aerial vehicles (UAVs) and computer vision techniques has contributed to enhancing the accuracy and speed of monitoring for surveillance and warning systems. This paper presents an application of human detection in a beach-warning-system using drone-captured images and YOLO. Our research focuses on detecting critical objects and anomalies on the beach, such as people or buoys. By leveraging the real-time capabilities of YOLO, our system processes highresolution drone images to swiftly identify and classify objects, enabling rapid responses in emergencies. We conducted evaluations using several methods to validate the model's effectiveness. The results showcase its potential to enhance beach warning systems and quick warning of dangerous situations.
Nguyen Phuong Thuy(Nguyen Phuong Thuy ),Nguyen Ngoc Trai(Nguyen Ngoc Trai ),Bui Dang Khoa(Bui Dang Khoa ),Nguyen Hoang Xuan Thao(Nguyen Hoang Xuan Thao ),Vuong Tuan Phong(Vuong Tuan Phong ),Quach Van 한국육종학회 2023 Plant Breeding and Biotechnology Vol.11 No.2
Genetic variability and correlation analysis are fundamental references for the innovative development of breeding programs to improve varieties and desirable traits. In the present study, the correlation and path analysis was conducted to understand the association among yield, micronutrients (iron and zinc), and protein content under aerobic conditions in local rice landraces from various agro ecological regions of Karnataka, India. The grain yield per plant showed a significant positive correlation with plant height, the tiller number, spikelet fertility, flag leaf length, and test weight. The zinc content was negatively correlated with grain yield per plant. The phenotypic path-coefficient analysis revealed that the total number of tillers, grain length, test weight, and harvest index exhibited a positive direct effect on grain yield per plant, while Grain protein content showed a low direct effect on this trait. This study also indicated that harvest index, flag leaf length, spikelet fertility, and test weight could be considered to make for a higher yield.
Ngoc T. B. Hoang,Binh V. Bui 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.6
The calculation of aerodynamic characteristics of a wing is the basic problem for aerodynamic design of aircraft. Wing aerodynamics can be determined experimentally and numerically. The method of fixing the wing in the test chamber of wind tunnel is related to disturbance of flow through the wing. When the wing is entirely fixed in the test chamber, the disturbance is usually caused by the sting connecting the wing to the test chamber. The experiments in this paper fixed the wing by clamping to the wind tunnel wall at the wing symmetry surface (root section). With this wing fixation, it was possible to take advantage of the wingspan twice, but to obtain the 3D wing experiment results, it was necessary to evaluate the impact of the wind tunnel wall effect. As for aircrafts, the aerodynamic force of the aircraft’s wing will have certain difference than that of the wing alone. The intersection region between the wind tunnel wall and wing root (for the experiment), as well as between the fuselage and wing root have complex interactions of boundary layers, in particular separation phenomena in the boundary layers. By solving the differential equation for viscous flows, it was possible to visualize the picture of streamlines and flow separations in this interference region and the aerodynamic characteristics of the wing. The singularity method was also used to compare results within its application range. The aerodynamic coefficients in the two cases with and without interference were analyzed. Complex interactions in the interference region could alter the predicted aerodynamic force calculated for the wing alone, which should be estimated. Very strong separations in the wing-fuselage interference region at large angles of attack turned into vortices at the rear impacting on the horizontal tail aerodynamics that is related to the balance problem of the aircraft.
Experimental and numerical studies of wingtip and downwash effects on horizontal tail
Ngoc T. B. Hoang,Binh V. Bui 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2
Studying wing downwash, which is caused by the wingtip effect, and its influence on horizontal tail is important for aircraft design. In this work, wing downwash was investigated using experimental and numerical methods. Sets of main wings and horizontal tails were fixed in a tunnel test chamber. For determining the wingtip effect and the wing downwash affecting the horizontal tail, experiments were performed, in which the pressure distributions near the main wingtip and on the upper and lower surfaces of the tail were measured. These experimental models were used in numerical calculations by the solving of differential equations for viscous flows and use of a singularity method for potential flows. The singularity method can be applied to determine the wing lift, as indicated by comparisons between the experimental and numerical results of the pressure distribution on the wing. Moreover, the wingtip and wing downwash effects influencing the horizontal tail should be determined with use of experimental and numerical methods that solve differential equations of viscous flow. In addition to the results regarding the pressure distributions near the main wing and on the horizontal tail, the longitudinal velocity, downwash velocity, and downwash angle distributions in the main wing wake were analyzed. We also investigated the kinetic parameters of the flow in mixed zones between the main wing downwash and the tail upwash.
Le Hoang Sinh,신승한,임동국,Nguyen Ngoc Trung,Bui Thanh Son,배진영 한국고분자학회 2013 Macromolecular Research Vol.21 No.10
A novel all aromatic 2,7-naphthalene-based liquid crystalline epoxy (LCE) was synthesized successfully in this study. The thermal transition of the synthesized LCE was characterized by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and polarized optical microscopy (POM). The characterization showed that the LCE had a low melting temperature of 65 oC and was in a nematic state in temperature range of 65-75 oC. The curing reaction between LCE and 4,4'-diaminodiphenylsulfone (DDS) was investigated, using 2-methylimidazole (2MI) as the reaction catalyst. Upon the addition of 1 phr of 2MI, the curing temperature was dramatically decreased from 227 to 128 oC, which is 99 oC lower than that of a reaction without the use of a catalyst system.
Effects of Foreign Direct Investment and Human Capital on Labour Productivity: Evidence from Vietnam
Nguyen Hoang LE,Luong Vinh Quoc DUY,Bui Hoang NGOC 한국유통과학회 2019 The Journal of Asian Finance, Economics and Busine Vol.6 No.3
The paper aims to investigate whether foreign direct investment (FDI) has positive effect on the labour productivity in Vietnam. Labour productivity is the elemental determinant of a country’s development level in long-term. In recent years, although increasing consistently, labour productivity of Vietnam remains low in comparison to other South East Asian countries. To identify the direction of effect and the level of effect of FDI and human capital on the labour productivity of Vietnam, Autoregressive Distributed Lag (ARDL) model was used to examine the effect of FDI and human capital on labour productivity in Vietnam from 1986 to 2014. The results of bounds test confirm the existence of cointegration among the variables. Further, the Toda and Yamamoto Granger causality test affirms that there is unidirectional causality running from foreign direct investment and human capital index to labour productivity. The empirical results provide strong statistical evidence that foreign direct investment and human capital has a positive impact on labour productivity in Vietnam in long-term. These findings imply that workers are expected to further improve their knowledge, skills and that policy-maker should establish concrete plans to increase human capital. Results from this study provide suggestion necessary for Vietnam to achieve sustainable development.