Parameter Estimation and Predictive Speed Control of Chopper-Fed Brushed DC Motors

This paper presents an effective speed control method for brushed DC motors fed by a DC chopper using the concept of Finite Control Set-Model Predictive Control (FCS-MPC). As this control algorithm requires the parameters of the controlled object, the estimation of motor parameters is first performed by using two types of data. The first data includes the output speed response corresponding to the step input voltage to obtain the transfer function in the no-load regime. The second data consists of the motor speed and armature current when a load torque is applied to the motor shaft. The discrete-time equation of the motor armature circuit is used to obtain the future values of the armature circuit current and the motor speed. A cost function is defined based on the difference between the reference and predicted motor speed. The optimal switching states of the DC chopper are selected corresponding to the maximum value of the cost function. The performance of the proposed speed control algorithm is validated on an experimental system. The simulation and experimental results obtained show that the MPC controller can outperform the conventional proportional-integral (PI) controller

A Machine Learning-based Approach to Vietnamese Handwritten Medical Record Recognition

Handwritten text recognition has been an active research topic within computer vision division. Existing deep-learning solutions are practical; however, recognizing Vietnamese handwriting has shown to be a challenge with the presence of extra six distinctive tonal symbols and extra vowels. Vietnam is a developing country with a population of approximately 100 million, but has only focused on digitalization transforms in recent years, and so Vietnam has a significant number of physical documents, that need to be digitized. This digitalization transform is urgent when considering the public health sector, in which medical records are mostly still in hand-written form and still are growing rapidly in number. Digitization would not only help current public health management but also allow preparation and management in future public health emergencies. Enabling the digitalization of old physical records will allow efficient and precise care, especially in emergency units. We proposed a solution to Vietnamese text recognition that is combined into an end-to-end document-digitalization system. We do so by performing segmentation to word-level and then leveraging an artificial neural network consisting of both convolutional neural network (CNN) and a long short-term memory recurrent neural network (LSTM) to propagate the sequence information. From the experiment with the records written by 12 doctors, we have obtained encouraging results of 6.47% and 19.14% of CER and WER respectively

Impact of trained human resources, adoption of technology and international standards on the improvement of accounting and auditing activities in the agricultural sector in Viet Nam

Recently, the adoption of accounting and auditing standards in the agricultural sector has been a global phenomenon that has gained increasing trend due to the significant role of the agricultural industry in the country's economy. Thus, the present study examines the impact of trained human resources, technology adoption, and international standards on improving accounting and auditing activities in the agricultural sector in Vietnam. The present research investigates the moderating impact of agricultural, institutional support among the linkage of trained human resources, technology adoption, international standards, and improvement of accounting and auditing activities in the agricultural sector. The present article has adopted the questionnaires to gather the primary data from selected respondents. The current research has applied the smart-PLS to test the study's hypotheses. The results revealed that trained human resources, technology adoption, and international standards positively impact the improvement of accounting and auditing activities in the agricultural sector. The findings also indicated that the agricultural institutional support significantly moderates the linkage of trained human resources, technology adoption, international standards, and improved accounting and auditing activities in the agricultural sector.Nguyen Van Hoa (University of Kinh Bac (UKB)), Nguyen Thi Hanh Duyen (Vinh University), Vu Ngoc Huyen (Viet Nam National University of Agriculture (VNUA)), Hoang Vu Quang (Researcher at Institute of Policy and Strategy for Agriculture and Rural Development (IPSARD)), Nguyen Van Huong (Hung Yen University of Technology and Education (UTEHY)), Nguyen Thi Cam Tu (National Economics University (NEU)), Bui Thi Minh Nguyet (Vietnam National University of Forestry (VNUF))Includes bibliographical references

Slip Resistance Test Apparatus of Synthetic Rubber Trackpad on Photovoltaic Surface

The increasing development of the solar energy industry in many countries has led to a rising frequency of human and robot presence in this area. To ensure occupational safety, various protective equipment, including rubber material, is commonly used for slip resistance while moving on the surface of solar PV panels. Therefore, the slip resistance test apparatus is built for testing the slip resistance between the synthetic rubber trackpad and the photovoltaic panel (PV) surface. Synthetic rubber is a man-made material, so it is difficult to control the parameters of its mechanical and chemical properties absolutely. Variations in wet/dry working conditions or Shore hardness are factors that make slip computation more challenging. Therefore, an apparatus with the principle of converting the reciprocating motion of the screw and the casters into the rotation of the hinge is introduced to adjust the tilt angle of the upper surface, detect and evaluate the slippage of the rubber trackpad by sensors. Some parameters related to accuracy such as vibration and theoretical-empirical assessment, are also mentioned. In addition to designing a reliable apparatus, the article also succeeded in providing a safety standard for synthetic rubber with Shore A30-A40 when moving on PV surfaces.Comment: 4 pages, 10 figures, The 20th International Conference on Ubiquitous Robots (UR 2023

Risk Factors for Human Infection with Avian Influenza A H5N1, Vietnam, 2004

TOC Summary: Risk factors include direct or household contact with sick or dead poultry and absence of an indoor water source

Flexible interactive retrieval SysTem 3.0 for visual lifelog exploration at LSC 2022

Building a retrieval system with lifelogging data is more complicated than with ordinary data due to the redundancies, blurriness, massive amount of data, various sources of information accompanying lifelogging data, and especially the ad-hoc nature of queries. The Lifelog Search Challenge (LSC) is a benchmarking challenge that encourages researchers and developers to push the boundaries in lifelog retrieval. For LSC'22, we develop FIRST 3.0, a novel and flexible system that leverages expressive cross-domain embeddings to enhance the searching process. Our system aims to adaptively capture the semantics of an image at different levels of detail. We also propose to augment our system with an external search engine to help our system with initial visual examples for unfamiliar concepts. Finally, we organize image data in hierarchical clusters based on their visual similarity and location to assist users in data exploration. Experiments show that our system is both fast and effective in handling various retrieval scenarios

High prevalence of plasmid-mediated quinolone resistance determinants in commensal members of the Enterobacteriaceae in Ho Chi Minh City, Vietnam

Antimicrobial-resistant pathogenic members of the Enterobacteriaceae are a well-defined global problem. We hypothesized that one of the main reservoirs of dissemination of antimicrobial resistance genes in Vietnam is non-pathogenic intestinal flora, and sought to isolate antimicrobial-resistant organisms from hospitalized patients and non-hospitalized healthy individuals in Ho Chi Minh City. The results identified substantial faecal carriage of gentamicin-, ceftazidime- and nalidixic acid-resistant members of the Enterobacteriaceae in both hospitalized patients and non-hospitalized healthy individuals. A high prevalence of quinolone resistance determinants was identified, particularly the qnrS gene, in both community- and hospital-associated strains. Furthermore, the results demonstrated that a combination of quinolone resistance determinants can confer resistance to nalidixic acid and ciprofloxacin, even in the apparent absence of additional chromosomal resistance mutations in wild-type strains and laboratory strains with transferred plasmids. These data suggest that intestinal commensal organisms are a significant reservoir for the dissemination of plasmid-mediated quinolone resistance in Ho Chi Minh City

The impact of environmental and climatic variation on the spatiotemporal trends of hospitalized pediatric diarrhea in Ho Chi Minh City, Vietnam.

It is predicted that the integration of climate-based early warning systems into existing action plans will facilitate the timely provision of interventions to diarrheal disease epidemics in resource-poor settings. Diarrhea remains a considerable public health problem in Ho Chi Minh City (HCMC), Vietnam and we aimed to quantify variation in the impact of environmental conditions on diarrheal disease risk across the city. Using all inpatient diarrheal admissions data from three large hospitals within HCMC, we developed a mixed effects regression model to differentiate district-level variation in risk due to environmental conditions from the overarching seasonality of diarrheal disease hospitalization in HCMC. We identified considerable spatial heterogeneity in the risk of all-cause diarrhea across districts of HCMC with low elevation and differential responses to flooding, air temperature, and humidity driving further spatial heterogeneity in diarrheal disease risk. The incorporation of these results into predictive forecasting algorithms will provide a powerful resource to aid diarrheal disease prevention and control practices in HCMC and other similar settings

Usporedba enzimske i ultrazvučne ekstrakcije albumina iz praha kondicioniranih sjemenki bundeve (Cucurbita pepo)

In this study, ultrasound- and enzyme-assisted extractions of albumin (water-soluble protein group) from defatted pumpkin (Cucurbita pepo) seed powder were compared. Both advanced extraction techniques strongly increased the albumin yield in comparison with conventional extraction. The extraction rate was two times faster in the ultrasonic extraction than in the enzymatic extraction. However, the maximum albumin yield was 16 % higher when using enzymatic extraction. Functional properties of the pumpkin seed albumin concentrates obtained using the enzymatic, ultrasonic and conventional methods were then evaluated. Use of hydrolase for degradation of cell wall of the plant material did not change the functional properties of the albumin concentrate in comparison with the conventional extraction. The ultrasonic extraction enhanced water-holding, oil-holding and emulsifying capacities of the pumpkin seed albumin concentrate, but slightly reduced the foaming capacity, and emulsion and foam stability.U ovom su radu uspoređena dva postupka izolacije albumina, proteina topljivog u vodi, iz praha kondicioniranih sjemenki bundeve (Cucurbita pepo), i to ekstrakcijom pomoću ultrazvuka te pomoću enzima. U usporedbi s konvencionalnom ekstrakcijom, oba su postupka znatno povećala prinos albumina. Ultrazvučna je ekstrakcija bila dva puta brža od enzimske, međutim, najveći je prinos albumina od 16 % dobiven enzimskom ekstrakcijom. Ispitana su funkcionalna svojstva koncentrata albumina dobivenog iz sjemenki bundeve enzimskom, ultrazvučnom i konvencionalnom ekstrakcijom. Enzimska hidroliza nije utjecala na funkcionalna svojstva koncentrata albumina, za razliku od konvencionalne ekstrakcije. Ultrazvučnom su ekstrakcijom poboljšana svojstva zadržavanja vode i ulja te emulgiranja, a neznatno smanjena svojstva pjenjenja te stabilnost pjene i emulzije koncentrata albumina