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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.
Synchronization Controller for a 3-RRR Parallel Manipulator
Khoa Dang Nguyen,하철근,Truong Quang Dinh,James Marco 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.3
A 3-RRR parallel manipulator has been well-known as a closed-loop kinematic chain mechanism in which the end-effector generally a moving platform is connected to the base by several independent actuators. Performance of the robot is decided by performances of the component actuators which are independently driven by tracking controllers without acknowledging information from each other. The platform performance is degraded if any actuator could not be driven well. Therefore, this paper aims to develop an advanced synchronization (SYNC) controller for position tracking of a 3-RRR parallel robot using three DC motor-driven actuators. The proposed control scheme consists of three sliding mode controllers (SMC) to drive the actuators and a supervisory controller named PID-neural network controller (PIDNNC) to compensate the synchronization errors due to system nonlinearities, uncertainties and external disturbances. A Lyapunov stability condition is added to the PIDNNC training mechanism to ensure the robust tracking performance of the manipulator. Numerical simulations have been performed under different working conditions to demonstrate the effectiveness of the suggested control approach.
Khoa Dang Nguyen,하철근 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.1
Quad-rotors are a common type of small unmanned aerial vehicles (UAVs) that consist of a body frame connected to four independent motors. The motors in quad-rotor UAVs are independently controlled by tracking controllers, which receive no information for each other. The overall performance of quad-rotor UAVs is affected by the performance of its motor control. Therefore, poor performance in the control of its motors causes the overall performance of quad-rotor UAVs to deteriorate. In this paper, we address this issue by developing a synchronization controller (SYNC) for a quad-rotor UAV for achieving the station-keeping hovering. The proposed control scheme consists of two controllers, which include a sliding mode controller (SMC) that is used to control the motor velocity, and a motor synchronization controller (M_SYNC) based on a PID and neural network controller that is used to compensate for the synchronization errors that occur between the motors due to system nonlinearities, uncertainties and external disturbances. To guarantee the stability of the quad-rotor UAV, a Lyapunov stability condition was introduced to design both the SMC and the M_SYNC. The proposed SYNC controller was evaluated through numerical simulations. The simulation results demonstrate that the SYNC controller was effective at improving the tracking performance of the UAV.
Khoa Dang Nguyen,하철근 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.1
Hardware-in-the-loop simulation (HILS) is well known as an effective approach in the design of unmanned aerial vehicles (UAV) systems, enabling engineers to test the control algorithm on a hardware board with a UAV model on the software. Performance of HILS is determined by performances of the control algorithm, the developed model, and the signal transfer between the hardware and software. The result of HILS is degraded if any signal could not be transferred to the correct destination. Therefore, this paper aims to develop a middleware software to secure communications in HILS system for testing the operation of a quad-rotor UAV. In our HILS, the Gazebo software is used to generate a nonlinear six-degrees-offreedom (6DOF) model, sensor model, and 3D visualization for the quad-rotor UAV. Meanwhile, the flight control algorithm is designed and implemented on the Pixhawk hardware. New middleware software, referred to as the control application software (CAS), is proposed to ensure the connection and data transfer between Gazebo and Pixhawk using the multithread structure in Qt Creator. The CAS provides a graphical user interface (GUI), allowing the user to monitor the status of packet transfer, and perform the flight control commands and the real-time tuning parameters for the quad-rotor UAV. Numerical implementations have been performed to prove the effectiveness of the middleware software CAS suggested in this paper.
Nguyen, Khoa Dang,Ha, Cheolkeun The Korean Society for Aeronautical Space Sciences 2018 International Journal of Aeronautical and Space Sc Vol.19 No.1
Hardware-in-the-loop simulation (HILS) is well known as an effective approach in the design of unmanned aerial vehicles (UAV) systems, enabling engineers to test the control algorithm on a hardware board with a UAV model on the software. Performance of HILS is determined by performances of the control algorithm, the developed model, and the signal transfer between the hardware and software. The result of HILS is degraded if any signal could not be transferred to the correct destination. Therefore, this paper aims to develop a middleware software to secure communications in HILS system for testing the operation of a quad-rotor UAV. In our HILS, the Gazebo software is used to generate a nonlinear six-degrees-of-freedom (6DOF) model, sensor model, and 3D visualization for the quad-rotor UAV. Meanwhile, the flight control algorithm is designed and implemented on the Pixhawk hardware. New middleware software, referred to as the control application software (CAS), is proposed to ensure the connection and data transfer between Gazebo and Pixhawk using the multithread structure in Qt Creator. The CAS provides a graphical user interface (GUI), allowing the user to monitor the status of packet transfer, and perform the flight control commands and the real-time tuning parameters for the quad-rotor UAV. Numerical implementations have been performed to prove the effectiveness of the middleware software CAS suggested in this paper.
Application of Electrocoagulation for Printing Wastewater Treatment: From Laboratory to Pilot Scale
Thuy, Nguyen Thi,Hoan, Nguyen Xuan,Thanh, Dang Van,Khoa, Pham Minh,Tai, Nguyen Thanh,Hoang, Quang Huy,Huy, Nguyen Nhat The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.1
This study reports for the first time the application of electrocoagulation (EC) from laboratory to pilot scales for the treatment of printing wastewater, a hazardous waste whose treatment and disposal are strictly regulated. The wastewater was taken from three real printing companies with strongly varying characteristics. The treatment process was performed in the laboratory for operational optimization and then applied in the pilot scale. The weight loss of the electrode and the generation of sludge at both scales were compared. The results show that the raw wastewater should be diluted before EC treatment if its COD is higher than about 10,000 mg/L. Pilot scale removal efficiencies of COD and color were slightly lower compared to those obtained from the laboratory scale. At pilot scale, the effluent CODs removal efficiency was 81.9 - 88.9% (final concentration of 448 - 992 mg/L) and color removal efficiency was 95.8 - 98.6% (final level of 89 - 202 Pt-Co) which proved the feasibility of EC treatment as an effective pre-treatment method for printing wastewater as well as other high colored and hard-biodegradable wastewaters.
Disputes in Managing Projects: A Case Study of Construction Industry in Vietnam
VO, Khoa Dang,NGUYEN, Phong Thanh,NGUYEN, Quyen Le Hoang Thuy To Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8
The construction industry in developing countries like Vietnam, which incorporates small and medium construction enterprises, is typically more prone to disputes and contract dispute-related lawsuits. A dispute may occur at any time in the life cycle of the project. It is sometimes solved with the intermediation of a lawyer or directly by stakeholders. Understanding the causes of disputes in a construction project not only improves the efficiency of a company but also increases the success of projects. This study was carried out using a questionnaire survey at construction projects in Ho Chi Minh City. Sample data with 117 observations were analyzed to find the disputing factors in construction projects: diversity of working style among the parties; reluctance to work; and poor teamwork. Correlation coefficient on a rank of factors between design consultant and contractor; Design consultant and project owners are positively correlated. The Exploratory Factor Analysis (EFA) analysis identified six groups of factors in construction disputes: cooperation, technology, economics, productivity, information, and behavior. The findings are useful for enterprise practice and provide participants with an overview of sources of dispute. Thus, a more complete risk management plan can be formulated, which will accelerate project progress and improve the likelihood of success.