Factors Affecting Infrastructure Connectivity: An Indian and Vietnamese Perspective

Thuy T.Dang,Nguyen Le Thy Thuong,Pham Thuy Nguyen 한국외국어대학교 인도연구소 2021 남아시아연구 Vol.27 No.3

Infrastructure connectivity plays an important role in Vietnam and India’s trade promotion, and international economic development and cooperation. Vietnam and India have become comprehensive strategic partners since 2016. In its “Act East” Policy, India considered Vietnam as a crucial destination for infrastructure development, trading and investment projects as well as a bridge to connect India with the Southeast Asia region. The article presents direct factors affecting infrastructure connectivity between India and Vietnam, in different aspects including geography and nature; politics and diplomacy; finance and economics; institutional policies and regulations; society and people; and infrastructure. From analyzing these factors, it can be seen that the harmonious diplomatic relations, stable internal politics and the increase in cooperation between Vietnam and India in various fields contribute to ensuring Vietnam - India infrastructure connectivity cooperation. A young, highly skilled workforce and a strong culture of integration also create favorable conditions for infrastructure connectivity between the two countries. However, the remote geographical distance, the limited economic resources, the relative disparity in the level of development of hard and soft infrastructure as well as the limited institutional capacity of each country create certain barriers. Due to the delay in decision-making and planning between the two countries, no direct projects between the two countries have been implemented so far. Currently, it is only possible to place the Vietnam - India infrastructure connectivity projects in the ASEAN - India infrastructure connectivity network, but most of these projects also stop at drafting and planning phase. Therefore, the infrastructure connectivity between Vietnam and India needs to overcome many barriers to achieve certain results.

Comparative study on Corrosion Inhibition of Vietnam Orange Peel Essential Oil with Urotropine and Insight of Corrosion Inhibition Mechanism for Mild Steel in Hydrochloric Solution

Bui, Huyen T.T.,Dang, Trung-Dung,Le, Hang T.T.,Hoang, Thuy T.B. The Korean Electrochemical Society 2019 Journal of electrochemical science and technology Vol.10 No.1

The corrosion inhibiting mechanism of Vietnam orange peel essential oil (OPEO) for mild steel in 1 N HCl solution was investigated elaborately. Corrosion inhibition ability of OPEO was characterized by electrochemical polarization, electrochemical impedance spectroscopy (EIS), and weight loss method. In the corrosive solution, OPEO worked as a mixed inhibitor and the inhibition efficiency of OPEO increased with the increase of its concentration. High inhibition efficiencies over 90% were achieved for the concentration of 3 - 4 g/L OPEO, comparable to that of 3.5 g/L urotropine (URO), a commercial corrosion inhibitor for acid media used in industry. By using adsorption isotherm models (Langmuir, Temkin and Frumkin), thermodynamic parameters of adsorption were calculated. The obtained results indicated physical adsorption mechanism of OPEO on the steel surface. The components responsible for the corrosion inhibition activity of OPEO were not only D-limonene, but also other compounds, which contain C=O, C=C, O-H, C-O-C, -C=CH and C-H bonding groups in the molecules.

Copper Recovery from Printed Circuit Boards Waste Sludge: Multi-step Current Electrolysis and Modeling

Nguyen, Huyen T.T.,Pham, Huy K.,Nguyen, Vu A.,Mai, Tung T.,Le, Hang T.T.,Hoang, Thuy T.B. The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.2

Heavy metals recovery from Printed Circuit Boards industrial wastewater is crucial because of its cost effectiveness and environmental friendliness. In this study, a copper recovery route combining the sequential processes of acid leaching and LIX 984N extracting with an electrowinning technique from Printed Circuit Boards production's sludge was performed. The used residual sludge was originated from Hanoi Urban Environment One Member Limited Company (URENCO). The extracted solution from the printed circuit boards waste sludge containing a high copper concentration of 19.2 g/L and a small amount of iron (0.575 ppm) was used as electrolyte for the subsequent electrolysis process. By using a simulation model for multi-step current electrolysis, the reasonable current densities for an electrolysis time interval of 30 minutes were determined, to optimize the specific consumption energy for the copper recovery. The mathematical simulation model was built to calculate the important parameters of this process.

Load Balancing Routing Under Constraints of Quality of Transmission in Mesh Wireless Network based on Software Defined Networking

Le Huu Binh,Thuy-Van T. Duong 한국통신학회 2021 Journal of communications and networks Vol.23 No.1

Load balancing routing and quality of transmission(QoT) aware routing have been increasingly studied in mesh wirelessnetworks (WMN) to improve their performance. For the loadbalancing routing, the traffic bottleneck in the network can be resolved. However, it can decrease QoT because the routes may passthrough multiple hops. On the other hand, the QoT aware routingoften improves the QoT of the routes, but it can increase thetraffic bottleneck due to the unbalanced traffic load in the network. Therefore, the investigation of load balancing routing takinginto account QoT is very essential, especially in the case of a wideand ultra-high speed WMN. In this paper, we propose a load balancingrouting algorithm under the constraints of QoT for WMN. Our method uses the principle of the software defined networking(SDN) to choose the load balancing routes satisfying the constraintsof QoT. Our performance evaluations using OMNeT++ have shownthe effectiveness of the proposed algorithm in improving QoT of thedata transmission routes, increasing the packet delivery ratio andthe network throughput, decreasing the end-to-end delay.

Reinforcement learning for QoS-guaranteed intelligent routing in Wireless Mesh Networks with heavy traffic load

Thuy-Van T. Duong,Le Huu Binh,Vuong M. Ngo 한국통신학회 2022 ICT Express Vol.8 No.1

Wireless Mesh Networks is increasingly being applied widely with explosive traffic demand. This leads to a great challenge for traditional routing protocols in ensuring Quality of Service. We propose a QoS-guaranteed intelligent routing algorithm in this paper for WMN with heavy traffic load using reinforcement learning to improve its performance. We build a reward function for the Q-Learning algorithm to choose a route so that the packet delivery ratio is the highest. Concurrently, the learning rate coefficient is flexibly changed to determine constraints of the end-to-end delay. Our performance evaluations show that the proposed algorithm has significantly improved performance compared with other well-known routing algorithms.

IRSML: An intelligent routing algorithm based on machine learning in software defined wireless networking

Thuy-Van T. Duong,Le Huu Binh 한국전자통신연구원 2022 ETRI Journal Vol.44 No.5

In software-defined wireless networking (SDWN), the optimal routing technique is one of the effective solutions to improve its performance. This routing technique is done by many different methods, with the most common using integer linear programming problem (ILP), building optimal routing metrics. These methods often only focus on one routing objective, such as minimizing the packet blocking probability, minimizing end-to-end delay (EED), and maximizing network throughput. It is difficult to consider multiple objectives concurrently in a routing algorithm. In this paper, we investigate the application of machine learning to control routing in the SDWN. An intelligent routing algorithm is then proposed based on the machine learning to improve the network performance. The proposed algorithm can optimize multiple routing objectives. Our idea is to combine supervised learning (SL) and reinforcement learning (RL) methods to discover new routes. The SL is used to predict the performance metrics of the links, including EED quality of transmission (QoT), and packet blocking probability (PBP). The routing is done by the RL method. We use the Q-value in the fundamental equation of the RL to store the PBP, which is used for the aim of route selection. Concurrently, the learning rate coefficient is flexibly changed to determine the constraints of routing during learning. These constraints include QoT and EED. Our performance evaluations based on OMNeT++ have shown that the proposed algorithm has significantly improved the network performance in terms of the QoT, EED, packet delivery ratio, and network throughput compared with other wellknown routing algorithms.

An improved method of AODV routing protocol using reinforcement learning for ensuring QoS in 5G-based mobile ad-hoc networks

Binh Le Huu,Duong Thuy-Van T. 한국통신학회 2024 ICT Express Vol.10 No.1

5G-based MANET has received a lot of attention recently. Its fundamental feature is that nodes are constantly subjected to high traffic loads, while QoS requirements are extremely stringent. When applied to 5G-based MANETs, existing routing protocols have shown drawbacks. In this paper, we propose an enhanced AODV protocol solution for 5G-based MANETs. Using reinforcement learning, each node updates a state information database of intermediate nodes along routes to destinations. This database is used by the routing algorithm to find guaranteed QoS routes. Our solution is highly efficient in terms of throughput, end-to-end delay, and SNR, according to the simulation results.

유적 합체기가 포함된 공기-물-기름 분리 공정에 대한 3상 Eulerian 전산유체역학

임영일 ( Young-il Lim ),( Thuy T. Le ),박치균 ( Chi-kyun Park ),이병돈 ( Byung-don Lee ),김병국 ( Byung-gook Kim ),임동하 ( Dong-ha Lim ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.2

물이 포함된 원유는 oil separator 를 거쳐 물이 제거된다. 본 연구의 목적은 공기-물-기름 3상 혼합물에 대한 3차원 oil separator 의 분리성능을 예측하기 위하여 Eulerian 전산유체역학(CFD: computational fluid dynamics) 모델을 개발하는 것이다. 비압축성, 등온, 비정상상태 CFD 모델식은 공기상을 연속상으로, 물과 기름상을 분산상으로 정의하며, 운동량 보존식은 항력(drag force), 양력(lift force), 다공성매체 저항력을 포함한다. 또한, 난류현상으로 standard k-ε 모델이 이용된다. 물과 기름 출구압은 oil separator 의 액위를 결정하는 중요한 인자이며, 정상운전상태 액위 25 cm를 맞추기 위하여 측정압은 각각 6.3 kPa, 5.1 kPa으로 결정되었다. 시간에 따른 공기, 물, 기름의 부피분율의 변화를 조사하였고, 정상상태에 도달하였을 때, 물과 기름상의 침강속도를 oil separator의 종축 길이에 따라 분석하였다. 본 연구에서 제시된 CFD 모델로부터 얻은 oil separator의 기름분리성능은 99.85%이며, 실험값과 거의 일치하였다. 비교적 단순한 이 CFD 모델은 향후 oil separator의 구조를 변경하거나, 최적운전조건을 찾기 위하여 유용하게 사용될 수 있을 것이다. Water is removed from crude oil containing water by using oil separator. This study aims to develop a three-dimensional (3D) Eulerian computational fluid dynamics (CFD) model to predict the separation efficiency of airwater- oil separator. In the incompressible, isothermal and unsteady-state CFD model, air is defined as continuous phase, and water and oil are given as dispersed phase. The momentum equation includes the drag force, lift force and resistance force of porous media. The standard k-ε model is used for turbulence flow. The exit pressures of water and oil play an important role in determining the liquid level of the oil separator. The exit pressures were identified to be 6.3 kPa and 5.1 kPa for water and oil, respectively, to keep a liquid level of 25 cm at a normal operating condition. The time evolution of volume fractions of air, water and oil was investigated. The settling velocities of water and oil along the longitudinal separator distance were analyzed, when the oil separator reached a steady-state. The oil separation efficiency obtained from the CFD model was 99.85%, which agreed well with experimental data. The relatively simple CFD model can be used for the modification of oil separator structure and finding optimal operating conditions.

Examining FDI Spillover Effects on Productivity Growth: Firm-Level Evidence from Vietnam

Phuong Van Nguyen,Khoa T. Tran,Nga Thuy Thanh Le,Hoa Doan Xuan Trieu 중앙대학교 경제연구소 2020 Journal of Economic Development Vol.45 No.1

The relationship between foreign direct investment (FDI) and firm productivity still greatly concerns many researchers. Even though this topic has provided rich insight into the impacts of FDI spillovers, limited empirical research has been conducted to figure out the heterogeneous impact of such spillovers in the case of Vietnam. In this study, which employs the generalized methods of moments to investigate a sample of 537,772 enterprises operating in Vietnam in the period from 2007 to 2015, we examine how spillovers occur and how they can affect domestic firms’ productivity. Intra-industrial and regional spillovers impact negatively on the productivity of domestic firms. Regarding intra-industrial spillovers, only backward ones positively affect local productivity.

Phenothiazine Derivative as Organic Photocatalyst for Metal Free Atom Transfer Radical Polymerization

Hoan Minh Tran,Lan Ngoc Tan Phan,Thang Van Le,Thuy Thuy Truong,Tam Huu Nguyen,Khuong Tung Truong,Le-Thu T. Nguyen,Mai Thanh Phong,Ha Tran Nguyen 한국고분자학회 2019 폴리머 Vol.43 No.4

A novel organic photocatalyst, 4-(10H-phenothiazin-10-yl)-N,N-diphenylaniline (PDPA) has been successfully synthesized from triphenylamine and phenothiazine moiety via Buchwald-Hartwig C-N coupling. The chemical structure of catalyst was characterized via proton nuclear magnetic resonance (1H NMR) and the optical properties were investigated via UV-vis spectroscopy. The PDPA has been applied as an organic photocatalyst for metal free atom transfer radical polymerization (O-ATRP). The well-controlled molecular weights of polymethacrylates have been obtained with high yield of 95% and narrow polydispersity index (Đ).