Adaptive backstepping control for ship nonlinear active fin system based on disturbance observer and neural network

Adaptive backstepping control based on disturbance observer and neural network for ship nonlinear active fin system is proposed. One disturbance observer is given to observe the disturbances of the system, by this way, the response time is shorten and the negative impact of disturbance and uncertain elements of the system is reduced. In addition, radial basic function neural network (RBFNN) is proposed to approach the unknown elements in the ship nonlinear active fin system, therefor the system can obtain good roll reduction effectiveness and overcome the uncertainties of the model, the designed controller can maintain the ship roll angle at desired value. Finally, the simulation results are given for a supply vessel to verify the successfulness of the proposed controller

Designingan Adaptive PID Controller for Dissolved Oxygen Control of the Activated Sludge Wastewater Treatment using Hedge Algebras

In this paper, we present the design methodology of the coefficients of adjustment of classical PI controller based on hedge algebras approach (HA - Hedge Algebras) to improve the quality of operation of the system. The adjustment works online with a wide range of adjustment enough around the value calculated by empirical methods Ziegler - Nichols. Subjects selected for trial is the controller method for dissolved oxygen in the wastewater treatment system by activated sludge method. Through system simulation in Matlab or Simulink environment at some different reference values, the results have been evaluated for quality control shows that the response time and overshoot reduce significantly, static deviation level is small. Through these results, it can be tested on the control system for more complex subjects to evaluate the effectiveness of methods and practical applications on the industrial control systems

EFFECTS OF EFL STUDENTS’ USE OF METACOGNITIVE STRATEGIES IN EXTENSIVE READING TASKS ON THEIR READING PERFORMANCE AND ATTITUDES

Reading plays important role in teaching and learning a second language as in reading, information is acquired and processed before learners can reach the final goal of English learning – communication. Extensive reading is a helpful way to develop students’ reading habits. A quasi-experimental study with one group pretest-posttest design was conducted in the Vietnamese educational context to investigate the effects of students’ use of metacognitive strategies on intermediate learners’ reading performance and attitudes. The results indicated positive changes in learners’ performance and attitudes, especially in higher-order thinking ability. Thirty-two participants from the convenient sampling method attended a 10-week reading course with metacognitive strategies embedded in extensive reading tasks. The scores from tests showed an improvement in reading comprehension ability and higher-order thinking application. The data from the questionnaire and semi-structured interview contributes to the positive attitudes toward students towards reading activities. This study has discovered the significant effects on the awareness of learners and afterwards cognition thinking. Learners have achieved a higher level of cognitive reading, critical reading and positive attitudes towards reading activity.  Article visualizations

Differentiable Bayesian Structure Learning with Acyclicity Assurance

Score-based approaches in the structure learning task are thriving because of their scalability. Continuous relaxation has been the key reason for this advancement. Despite achieving promising outcomes, most of these methods are still struggling to ensure that the graphs generated from the latent space are acyclic by minimizing a defined score. There has also been another trend of permutation-based approaches, which concern the search for the topological ordering of the variables in the directed acyclic graph in order to limit the search space of the graph. In this study, we propose an alternative approach for strictly constraining the acyclicty of the graphs with an integration of the knowledge from the topological orderings. Our approach can reduce inference complexity while ensuring the structures of the generated graphs to be acyclic. Our empirical experiments with simulated and real-world data show that our approach can outperform related Bayesian score-based approaches.Comment: Accepted as a regular paper (9.37%) at the 23rd IEEE International Conference on Data Mining (ICDM 2023

Performance of export-oriented small and medium-sized manufacturing enterprises in Viet Nam

The study recommends the formulation of policies that support the development of business linkages and networking, and which promote subcontracting arrangements between small and large enterprises or between domestic firms and foreign investment enterprises. It is also necessary to support and facilitate the direct involvement of SMMEs in exporting or indirectly through large manufacturing enterprises.Export-oriented, SME,SMME, Viet Nam

PSO based Hybrid PID-FLC Sugeno Control for Excitation System of Large Synchronous Motor

This paper proposes a hybrid control system integrating a PID controller and a fuzzy logic controller, using the particle swarm optimization (PSO) algorithm to optimize control parameters. The control object is an excitation system for a large synchronous motor, which is widely used in large power transmission systems. In practice, the change in load and excitation source can affect the operating mode of the motor. Therefore, a hybrid controller is designed to stabilize the power factor, resulting in better working performance. In the control algorithm, a PID controller is initially designed using PSO to optimize the control coefficients. The FLC-Sugeno control is then integrated with the PID, in which PSO is utilized to optimize membership functions. Numerical simulation results demonstrate the advantages of the proposed approach. Doi: 10.28991/ESJ-2022-06-02-01 Full Text: PD

Improving indigenous Vietnamese Black Rabbit frozen sperm quality: the role of glycine and sperm selection methods

[EN] Rabbit sperm are known to undergo damage during both cryopreservation and thawing, leading to decreased viability, motility and membrane integrity. Glycine can protect sperm and reduce damage during freezing. Swim-up is a simple semen processing method for selecting good motile sperm. The study evaluated the effect of the swim-up method and glycine with different concentrations supplemented to the frozen medium. Three indigenous black rabbits were selected for semen collection by artificial vagina. Next, semen was selected by swim-up method and diluted with glycine-added frozen medium. The samples were then transferred to 0.5 mL straws, cooled to 15°C and 5°C, placed in liquid nitrogen vapour, and finally placed directly into liquid nitrogen (-196°C). The samples were thawed and evaluated for sperm quality. The results showed that the medium supplemented with 10mM glycine in combination with swim-up method for 30 min gave the best results and was significantly different from the remaining concentrations (P<0.01), with viability rate, overall mobility and membrane integrity of 68.0%, 58.7% and 49.7%, respectively. In conclusion, 10 mM glycine concentration combined with swim-up for 30 min is the optimal choice for freezing local black rabbit semen. The study highlights the importance of optimising freezing protocols to improve the quality of frozen rabbit sperm, which can have important implications for animal breeding and conservation efforts.This study is funded in part by the Can Tho University, Code: T2022-133Tran, TTT.; Duy, NLK.; Hang, NT.; Ngoc, PK.; Tuyen, DND. (2023). Improving indigenous Vietnamese Black Rabbit frozen sperm quality: the role of glycine and sperm selection methods. World Rabbit Science. 31(4):229-236. https://doi.org/10.4995/wrs.2023.1969022923631

Application of PCR-DGGE method for identification of nematode communities in pepper growing soil: Ứng dụng phương pháp PCR-DGGE để định danh cộng đồng tuyến trùng trong đất trồng hồ tiêu

Soil nematodes play an important role in indication for assessing soil environments and ecosystems. Previous studies of nematode community analyses based on molecular identification have shown to be useful for assessing soil environments. Here we applied PCR-DGGE method for molecular analysis of five soil nematode communities (designed as S1 to S5) collected from four provinces in Southeastern Vietnam (Binh Duong, Ba Ria Vung Tau, Binh Phuoc and Dong Nai) based on SSU gene. By sequencing DNA bands derived from S5 community sample, our data show 15 species containing soil nematode, other nematode and non-nematode (fungi) species. Genus Meloidogyne was found as abundant one. The genetic relationship of soil nematode species in S5 community were determined by Maximum Likelihood tree re-construction based on SSU gene. This molecular approach is applied for the first time in Vietnam for identification of soil nematode communities.Tuyến trùng đất đóng vai trò chỉ thị quan trọng trong công tác đánh giá môi trường và hệ sinh thái đất. Các nghiên cứu trước đây đã cho thấy lợi ích của việc phân tích cộng đồng tuyến trùng đất bằng định danh sinh học phân tử đối với việc đánh giá môi trường đất. Ở đây, chúng tôi ứng dụng phương pháp PCR-DGGE dựa trên gene SSU để phân tích năm (ký hiệu từ S1 đến S5) cộng đồng tuyến trùng đất thuộc các vùng trồng chuyên canh cây hồ tiêu ở miền nam Việt Nam (Bình Dương, Bà Rịa Vũng Tàu, Bình Phước và Đồng Nai). Bằng cách giải trình tự các vạch của mẫu tuyến trùng S5, kết quả cho thấy cộng đồng tuyến trùng này có 15 loài gồm nhóm tuyến trùng đất, nhóm các loại tuyến trùng khác và nhóm không phải tuyến trùng (nấm) và trong đó Meloidogyne là giống ưu thế. Mối quan hệ di truyền của các các loài tuyến trùng đất thuộc cộng đồng S5 được xác định bằng việc thiết lập cây phát sinh loài Maximum Likelihood dựa trên gene SSU. Đây là nghiên cứu đầu tiên ở Việt Nam sử dụng kỹ thuật PCR-DGGE để phân tích các cộng đồng tuyến trùng đất trồng hồ tiêu

Experimental results of gaslift process

In the paper, the investigation results of periodical gas-lift flows in vertical pipes using experiment method are presented. The experiment facilities consist of flow measurement equipment, gas and fluid supplier facilities, tubing system. To study the influence of medium physical and dynamical characteristics on the process efficiency, two liquid-gas systems are used, namely, water-air and spindle oil-air. The objects of investigation are to obtain data from tests conducted in some conduits and to analyse the influence of system physical, geometrical and etc. parameters such as: initial liquid height in the conduits, gas injected volume, conduit diameter, conduit configuration and etc. on the considered process