A Study on the Multipath RPL overMAC 802.15.4e systems

Dinh-Sy Do,Ngoc-Thanh Dinh,Yongju Lee,Younghan Kim,Munho Song 한국통신학회 2012 한국통신학회 학술대회논문집 Vol.2012 No.6

Exploiting Optimal Throughput of Adaptive Relaying Based Wireless Powered Systems under Impacts of Co-channel Interference

( Thanh-luan Nguyen ),( Dinh-thuan Do ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.5

Considering a dual-hop energy-harvesting (EH) relaying system, this paper advocates novel relaying protocols based on adaptive time power switching-based relaying (AR) architecture for amplify-and-forward (AF) mode. We introduce novel system model relaying network with impacts of co-channel interference (CCI) and derive analytical expressions for the average harvested energy, outage probability, and the optimal throughput of the information transmission link, taking into account the effect of CCI from neighbor cellular users. In particular, we consider such neighbor users procedure CCI both on the relay and destination nodes. Theoretical results show that, in comparison with the conventional solutions, the proposed model can achieve optimal throughput efficiency for sufficiently small threshold SNR with condition of reasonable controlling time switching fractions and power splitting fractions in concerned AR protocol. We also explore impacts of transmission distances in each hop, transmission rate, the other key parameters of AR to throughput performance for different channel models. Simulation results are presented to corroborate the proposed methodology.

Modeling and Energy Management Strategy in Energetic Macroscopic Representation for a Fuel Cell Hybrid Electric Vehicle

Dinh, To Xuan,Thuy, Le Khac,Tien, Nguyen Thanh,Dang, Tri Dung,Ho, Cong Minh,Truong, Hoai Vu Anh,Dao, Hoang Vu,Do, Tri Cuong,Ahn, Kyoung Kwan The Korean Society for Fluid Power and Constructio 2019 드라이브·컨트롤 Vol.16 No.2

Fuel cell hybrid electric vehicle is an attractive solution to reduce pollutants, such as noise and carbon dioxide emission. This study presents an approach for energy management and control algorithm based on energetic macroscopic representation for a fuel cell hybrid electric vehicle that is powered by proton exchange membrane fuel cell, battery and supercapacitor. First, the detailed model of the fuel cell hybrid electric vehicle, including fuel cell, battery, supercapacitor, DC-DC converters and powertrain system, are built on the energetic macroscopic representation. Next, the power management strategy was applied to manage the energy among the three power sources. Moreover, the control scheme that was based on back-stepping sliding mode control and inversed-model control techniques were deduced. Simulation tests that used a worldwide harmonized light vehicle test procedure standard driving cycle showed the effectiveness of the proposed control method.

Space Vector Modulation Scheme for Three-Level T-Type Quasi-Switched Boost Inverter to Reduce Common Mode Voltage

Vinh-Thanh Tran,Duc-Tri Do,Minh-Khai Nguyen,Dinh-Tuyen Nguyen 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In this paper, a space vector pulse-width modulation (SVPWM) control scheme for the three-level quasi-switched boost T-type inverter (TL-qSBT2I) to reduce common mode is presented. The magnitude and slew rate of common-mode voltage (CMV) are reduced by using the proposed method. By properly selecting the shoot-through (ST) phase, the ST states are inserted within a small vector so that the active states and output voltage are unchanged. In this method, the ST duty cycle is kept constant to obtain the modulation index as high as possible while the duty cycles of the two additional switches are the control variables. The proposed method can mitigate the peak value of CMV up to 50% and the RMS value up to 35.3% as compared to the conventional SVPWM control method. To verify the operating principle of the TL-qSBT<SUP>2</SUP>I, the simulation and experimental results are shown.

Modeling and Energy Management Strategy in Energetic Macroscopic Representation for a Fuel Cell Hybrid Electric Vehicle

TOXUAN DINH,Le Khac Thuy,Nguyen Thanh Tien,Tri Dung Dang,Cong Minh Ho,Hoai Vu Anh Truong,Hoang Vu Dao,Tri Cuong Do,안경관 사단법인 유공압건설기계학회 2019 드라이브·컨트롤 Vol.16 No.2

Fuel cell hybrid electric vehicle is an attractive solution to reduce pollutants, such as noise and carbon dioxide emission. This study presents an approach for energy management and control algorithm based on energetic macroscopic representation for a fuel cell hybrid electric vehicle that is powered by proton exchange membrane fuel cell, battery and supercapacitor. First, the detailed model of the fuel cell hybrid electric vehicle, including fuel cell, battery, supercapacitor, DC-DC converters and powertrain system, are built on the energetic macroscopic representation. Next, the power management strategy was applied to manage the energy among the three power sources. Moreover, the control scheme that was based on back-stepping sliding mode control and inversed-model control techniques were deduced. Simulation tests that used a worldwide harmonized light vehicle test procedure standard driving cycle showed the effectiveness of the proposed control method.

베트남 물관리의 현황과 미래 전략

( Nguyen Chi Nghia ),( Do Truong Sinh ),( Nguyen Van Kenh ),( Tong Thanh Tung ),( Dinh Thi Thuong ) 한국수자원공사 2017 저널 물 정책·경제 Vol.28 No.-

베트남에서 수자원은 새로운 분야다. 2003년까지는 농업ㆍ농촌지역개발부(Ministry of Agriculture and Rural Development)가 지표수를 수문학적 관점에서 산정하여 관리하였으며, 지질ㆍ광물자원부터(the General Department of Geology and Minerals)에서 지하수를 조사하고 산정하였다. 이때까지 베트남에서는 `수자원`이라는 개념은 존재하지 않았으며, 물을 자원으로 생각하지 않아서 수자원 정책이나 수자원관리 체계가 마련되지 않은 상황이었다. 2003년 자연자원환경부(Ministry of Natural Resources and Environment) 수립 이후로, 수자원관리 체계가 점차 정립되었다. 2010년부터 베트남의 수자원관리는 크게 발전하였다. 2013년에는 수자원법이 발효되었고, 수자원 관련기관들이 설립되었다. 이후 수자원부문에 대한 투자 가치가 인정되어, 수자원부문에 대한 국가 예산 투자가 상당히 증가하였다. 구체적으로 수자원법수행 및 제도 구축을 위한 투자가 있었는데, 이와 관련하여 5개의 시행령, 22개의 시행규칙 및 20개의 국무총리 고시가 발표되었다. 또한 수자원관리를 위하여 조직 체질개선, 수자원 기초조사 등의 수자원 조사ㆍ감독 역량 강화, 수질오염 제한 및 수자원 보호, 수자원 개발ㆍ이용에 대한 효율적 관리, 국제 협력, 수자원부문의 과학 및 기술 발전, 수자원 법에 대한 선전, 국민의 수자원에 대한 인식 제고 등 다양한 노력이 있었다. 향후 2016-2020년 동안, 베트남 자연자원환경부는 수자원의 계량화, 수자원 인프라 투자 및 거버넌스 구축을 위한 국제협력 강화 등 수자원관리 역량을 향상시키기 위하여 필요한 사항을 점검하고 이에 집중할 것이다. 본 연구는 베트남의 지난 국가수자원계획의 성과를 평가해보고 그 한계점을 파악한 후, 2016-2020 국가수자원계획에 반영할 개선점을 진단하였다. 따라서 본 연구는 베트남 수자원 분야의 협력개발 및 프로젝트에 있어 훌륭한 기반이 될 것이다.

Energy Harvesting Protocol for Optimal Throughput in WLAN

Tan-Phuoc Huynh,Dinh-Thuan Do,Hoang-Sy Nguyen,Thanh-Dai Nguyen 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6

In this paper, the time power switching based relaying (TPSR) protocol is proposed for energy harvesting (EH) enabled mobile node in WLAN. Specifically, we investigate how the time and power factors in EH protocol at relay mobile node affects on outage probability and throughput performance. Specifically, we develop outage and throughput performance characterizations in term of time and power factors in the proposed scheme. The tightness of our proposed protocol is determined through simulation results. We confirm that the optimal throughput is critically dependent on time switching and power splitting factor of the TPSR protocol.

The Impact of Leadership Styles on the Engagement of Cadres, Lecturers and Staff at Public Universities - Evidence from Vietnam

Huynh Thi Thu Suong,Do Dinh Thanh,Truong Thi Xuan Dao 한국유통과학회 2019 The Journal of Asian Finance, Economics and Busine Vol.6 No.1

Many studies have shown that job performance and leadership are important in our society. In addition, to improve the quality of work or to improve the work efficiency is still a lot of challenges for each leader. In Vietnam, there are few specific studies on the impact of leadership styles on employee engagement such as: transformational leadership styles, business leadership styles and leadership styles. In the field of higher education, the fewer studies on these issues. A study is conducted to test the impact of leadership styles on the engagement of cadres, lecturers and staff at public universities in Vietnam. Using adjustment techniques, inspecting the scales and theoretical models representing the relationship among the influential factors. The research is based on a sample of 309 cadres, lecturers and staff currently working in universities in Vietnam and used Structural Equation Modeling (SEM) to test the relationships among the variables. The study results show that the scales of the variables: transformational leadership, transactional leadership, laissez faire leadership, job satisfaction and organizational engagement attain the validity and reliability in the research. The study results also show transformational leadership, transactional leadership and laissez faire leadership are directly and indirectly affected by job satisfaction and organizational commitment.

Investigation of Extruded Endwall on Heat Transfer Characteristics of Channel with Staggering Pin-fins

Van-Hoang Tran,Thanh-Huan Nguyen,Frédéric Plourde,Khanh-Duy Cong Do,Duy-Hung Chung,Cong-Truong Dinh,Gia-Diem Pham 한국유체기계학회 2023 International journal of fluid machinery and syste Vol.16 No.2

In order to increase turbine efficiency while retaining structural integrity, modern jet engines need an effective cooling system. Pin-fin arrays play a significant role in the internal cooling system of the turbine blade. In examining the efficacy of cooling techniques using pin-fins, the other papers focus on pin-fin configurations. In contrast, the current study is a step toward optimizing cooling cascade endwalls for better maneuvering and reservation of vortices, which leads to more considerable heat transfer near the endwalls. This study examines the flow field and heat transfer of roughed endwall in the pin-fin channel, including varieties with flat endwall and extruded endwall. The heat transfer of the channel and pressure drop properties of the extruded endwall case are quantitatively assessed to contrast with those of the flat endwalls scenario for an intake Reynolds number range of 7400 to 36000. The leading and trailing surfaces of the channel are divided into five streamwise regions to understand better how well the pin-fins and endwalls transmit heat. The results show that the new endwall construction significantly increases the high heat transfer zones around the pin-fins compared to the flat endwall scenario. In the meantime, the heat transfer of the channel to the pin-fins is enhanced by the modified endwall configuration. The redesigned endwall outperformed the basic case regarding the HTEI, rising by 15.9%. It is found that the friction factor of the new design is increased due to the narrowing channel. However, due to their much higher heat transfer capacity, the HTEI of extruded endwall is up to 41.5% higher than the HTEI of the channel with flat endwalls. These results demonstrate that the heat transfer properties of pin-fins can be significantly improved by optimizing endwall design.

Factors Affecting Employees' Organizational Commitment in Foreign Direct Investment Enterprises

NGUYEN, Thi Viet Nga,DO, Thanh Quang,DINH, Cong Hoang Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.10

This study aims to develop a research framework to investigate the factors affecting organizational commitment among employees who are working in Foreign Direct Investment (FDI) enterprises in Vietnam. The authors designed an online survey distributed to employees in FDI enterprises, collecting the data from 312 employees. All scales in this study are adopted from previous studies; tools employed include Cronbach's Alpha, Exploratory Factor Analysis, and Confirmatory Factor Analysis (CFA) to examine the internal consistency, reliability, dimensionality, and validity of each variable. Then, the structural equation modelling (SEM) was utilized in order to estimate path correlations between variables. Results indicate that the leadership style has the strongest effect on organizational commitment, followed by job satisfaction and working performance. Moreover, working performance and job satisfaction are also influenced by leadership style. However, there is no statistical evidence to show that job satisfaction has an impact on working performance. In addition, bootstrapping method is used to show the indirect effect of variables; results reveal that leadership style, though, does not have indirect effect on working performance via job satisfaction, but it indirectly affects organizational commitment throughout working performance. In other words, the study finds that working performance mediates the link between leadership style and organizational commitment.