This paper presents a solution of applying IoT technology in fire prevention from household gas leakages. The system consists of a smartphone application and an IoT circuit which can control equipment’s power supply, detect gas leakages, and monitor environment temperature. The smartphone application is built based on the Blynk tool, which is highly convenient and easy to install on popular smartphones. The hardware consists of an ESP8266 microcontroller that collects data from two sensors, including DS18B20 temperature sensor and MQ-02 gas detector. The microcontroller can alarm with a buzzer and cut off the power supply in the kitchen through an intermediate relay. The system software of the IoT circuit is integrated with the error compensation function, which is determined by the Levenberg-Marquardt least squares algorithm. In addition, the sensor data is also preprocessed to remove abnormal amplitude samples which is considered as noises. Experimental results show that the IoT circuit can detect gas leakages and release warning in a timely manner, without the appearance of "false alarms" like common gas sensors on the market.

The main purpose of this study was to monitor household electrical loads through Blynk application. Firstly, the article presents the structure and operation principle of the proposed monitoring model and components of model. Secondly, the control program is performed with the Arduino IDE software and loaded into the Esp8266 chip via a wifi network connection. The measurement data of the proposed model are compared with the obtained data of the EVNSPC customer service application of Vietnam Electricity Corporation. The results showed that the difference between two applications was from 0.98% to 5.21% of the measured data for a day and from 0.4% to 0.98% of the measured data for a month.

The Matlab App Designer was used to design the fault location simulation program for power transmission lines. The impedance-based methods are applied to determine the fault location on the transmission line via the voltage and current measurements at the single and double ends of the line. This program can be applied to several voltage level transmission lines, and it can be used to simulate four fault types with different fault locations and resistances along the line. Moreover, the program is packed to the *.exe file, so it can be installed into any computer without the Matlab software. The simulation results of the 220 kV and 110 kV transmission lines are studied to investigate the performance of the designed program. The simulation results showed that the program works effectively and correctly.

This paper is aimed to introduce a method evaluation the velocity of the water surface by using commercial camera. The camera was fixed at the top of a bridge, where it was possible to observe the river surface and vehicles passing by. The observation video was recorded in different oblique angles. Ortho-images were created from video frames by using collinearity equation and perspective transform. To estimate accuracy of the equations, experiment was taken on land before applying to river surface. The optical flow method was proposed to calculate the river surface’ velocity. The result shows that wave velocity vectors were fixed with waves generated by ships and small waves generated by nature effect. The initial results of the experiment show that although moving vehicles generated many waves, these waves have small amplitude and fast terminated.

Along with the development of agriculture, biopesticides are increasingly being researched because of their environmental friendliness, safety for users, and limit of pest resistance to drugs. This study was conducted to develop a process for the extraction of yam bean seed (Pachyrhizus erosus) containing the active ingredient rotenone, a potential active compound that is effective against omnivorous caterpillars (Spodoptera litura). The results showed that the optimal conditions for yam bean seed extraction were successfully extracted by chloroform at 2 extraction times with the sample powder: solvent ratio at 1:5 (g/mL) for 48 hours. The presence of rotenone was assessed by qualitative methods with reagents and thin-layer chromatography. Furthermore, a rotenone content of 0.14% in the extract was recorded by LC/MS/MS. The best killing effect on omnivorous caterpillars was recorded at a concentration of 15 g/L after 4 hours with a spray volume of 25 mL through the toxic taste path. In addition, the probiotics prepared from the extraction of yam bean seed were as effective as commercial biological products.

With its nonlinearity, instability, and data transmission delay, the beam and ball system is quite difficult to control. This study proposes to combine proportional-integral-derivative (PID) control and supervisory control using a radial basis function (RBF) neural network, called RBF-PID control, on a real beam and ball model. This model has been developed that integrated a compensator for sensor error and time delay. The PID controller plays the role of bringing the response close to the reference signal. The task of fine-tuning the response will be handled by the RBF controller. Experimental results on the beam and ball system with an ultrasonic positioning mechanism gave better results than the previous studies. Specifically, the response time was 1.5 ± 0.3 seconds; the settling time archived 6.5 ± 1.0 seconds; although the overshoot was still quite large, about 11 ± 2 %, the steady-state error was eliminated. The results showed that the RBF-PID controller is suitable for controlling the system.

In the few recent decades, the rapidly increasing digitalization of image documents, accurate information extraction has been an important research area of the document analysis community. Many research works have been conducted on element-based approach for document classification. In this paper, the objective addresses the POD (Page Object Detection) problem – detecting objects that appear in document pages, by evaluating 2 datasets: IIIT-AR-13K and UIT-DODV as the benchmark for the YOLOX method. YOLOX achieved 69,0% mAP on the UIT-DODV dataset and 66,9% mAP on the IIIT-AR-13K dataset. Compared to the highest result of the previous state-of-the-art of one-stage detector - YOLOv4x-mish, on the UIT-DODV dataset, YOLOX surpassed by 2,90% mAP. YOLOX is significantly lower in IIIT-AR-13K than in previously announced two-stage approaches. Furthermore, this research provided an analysis on the effectiveness of the state-of-the-art method YOLOX on the POD problem, which will become a premise for future researches.

In recent years, the situation change of saline water intrusion has unpredictably occurred in the coastal areas of the Mekong Delt ina, Viet Nam. This study aimed to map and evaluate the impacts of saline water intrusion and to propose adaptation measures for agro-forestry farming systems. The water salinity was measured at 136 locations combined with the interviews and participation rapid assessment discussion with 120 farmers were conducted to investigate the farming systems, cropping calendar, saline intrusion and disaster risks in the period 2018-2020, including on double rice cultivation, rice-shrimp farming, and Melaleuca-Acacia forest. The results indicated that the saline intrusion and disaster risks in 2020 were more severe than those in 2018 and 2019. The short-term, tolerance to salinity and acid sulphate soil rice variety and applied late cropping calendars were possible measures to the saline intrusion in double rice farming model. Moreover, black tiger shrimp (Penaeus monodon) was rasied for adaptation to high salinity while white-leg shrimp (Liptopenaeus vannamei) was chosen for low salinity or or ignored the rice season in rice-shrimp model when high salinity happened. Meanwhile, Melaleuca cajuputi and Acacia hybrids were planted at the end of the rainy season to increases the survival rates.

Land subsidence has been taking place in many locations in the Mekong Delta, due to a combination of natural and human activities. The application of radar remote sensing images in monitoring land subsidence has helped managers to capture fast and synchronous information on a large scale. The objectives of this study were to assess the possibility of using radar remote sensing for monitoring of land subsidence in Can Tho city. Persistent scatterer SAR interferometry (PSInSAR) method on Sentinel-1 time series data to analyze land subsidence was applied in this study. The results showed that theaverage land subsidence rate in Can Tho city was -13.2 mm/year and with the correlation coefficient of Pearson R ≈ 0.88 when compared to field measurement data,  and R ≈ 0.93 when compared to land subsidence data collected from GIZ, BGR and BKK. Therefore, the result showed that this is high possibility of using radar remote sensing to monitor land subsidence in Can Tho city.

This research aimed to estimate the greenhouse gas (GHG) emissions including CO2, CH4, and N2O from direct sources (petroleum consumption and fuel) and indirect sources (household electricity consumption and garbage) in Ninh Kieu district, Can Tho city. The fuel consumption data from different emission sources were collected using the interview approach on both sides including households and relevant management agencies. The total amount of GHG emissions was calculated based on the consumed fuel mass and the corresponding emission factors, and an average of the emissions per capita was also estimated. The results showed that in 2019, the total GHG emissions of Ninh Kieu district were about 1,069,422 tons of CO2eq, and the emissions per capita were about 4.17 tons of CO2eq/year. In which, the highest proportion in indirect emissions from electricity consumption at 35.1% and directly from fuels (gas, firewood, and coal) at 26.5%. The results identified the activities contributing to the high GHG emissions as a basis for proposing suitable activities to mitigate emissions for the Can Tho city toward the orientation of a carbon-neutral city.

This study was conducted with the aim of assessing the diversity of medicinal plants in Cu Lao Dung, Soc Trang province, that is as a scientific basis for more effectively using, managing and preserving this medicinal plant resource in this province. In this study, the PRA (Participatory Rural Appraisal), field investigation, morphological comparison and classification, with the aid of specialized medicinal plant books were used. The results showed that a total of 603 species of medicinal plants belonging to 418 genera of 134 families in 3 divisions. Among them, Magnoliophyta was the most diverse division with 97.18% species, 96.41% genera and 89.55% families. Three species were listed in “Red List of Vietnamese medicinal plants” (2006), “Vietnam Red Book” (2007) and the Decree 06/2019/ND-CP. The medicinal plant species were divided into eight life forms and distributed in seven biotopes. the most species diversity was recorded in garden biotope (including home gardens, orchards and herbal gardens). Ten parts of plants were used to medicate for 36 disease types. Twenty-five species were commonly used by local people.

This study proposed a genetic algorithm in building cluster for discrete elements, in which the similarity coefficient of cluster was used to evaluate the similarity of the elements, and the improved Davis-Boudin index was used as the objective. Combined with the steps of a traditional cluster analysis algorithm and the operators such as crossover, mutation, and selection of the genetic algorithm, a new cluster analysis algorithm was proposed. The proposed algorithm is detailed with the implementation steps, and illustrated by numerical examples. It is also applied in image recognition, a problem that is still challenging today. The application also shows the potential of this research to many real-world problems related to image recognition.

Shrimp farming is an industry that brings high economic value but also generates waste and wastewater into the environment. Traditional treatment methods requires extensive area and energy cost. Therefore the technologies of water treatment saves energy costs andbrings economic values are needed. This study used Chlorella vulgaris algae in combination with photo membrane bioreactor (PMBR) to test the adaptation in saline  water of 13‰ and evaluate the application to treat shrimp wastewater. The parameters such as nitrate, nitrite, ammonium, phosphorus, number of algae cells (cells/mL) and algal biomass (mg/mL) were analysed during 40 days of the study. The initial results showed that purebred algae are well adapted to shrimp farming wastewater's salinity reaching the highest level of more than 11×106 cells/mL, equivalent to a biomass of nearly 600 mg/mL. With the running mode that does not consume energy for air supply, the efficiency of N-NO2-, N-NO3-, N-NH4+, phosphorus removal of the model with shrimp farming wastewater 56, 76.15, 65 and 78.07%, respectively.

Microencapsulation is an effective method to preserve bioactive compounds. Through the encapsulation mechanism of polymers derived from proteins, polysaccharides; natural compounds (polyphenols, carotenoids,...), as well as beneficial microorganisms (yeast, probiotics), are protected against adverse environmental conditions. The application of microencapsulated beads in foodstuff prolongs the shelf life of products, improve the antioxidant capacity and enhance the survival of probiotics.

The factors such as microorganisms, ripening, and respiration can deteriorate the quality and quantity of fresh fruit after harvest if it is not stored in a suitable condition. The edible coating technique is one of the effective solutions for post-harvest fruit preservation, its mechanism seems like a semi-permeable membrane covering the surface of the peel and control the exchange of water and gas between the environment and fruit, as well as prevent the attack of harmful microorganisms. Coating treatment can be applied to preserve many tropical fruits to prolong their shelf life, maintain good organoleptic quality as well as biological compounds. Within the scope of this article, the characteristics of biofilm as well as its effectiveness in postharvest fruit preservation had been described.

Kien Giang has the potential to develop agriculture, forestry, fisheries, and the maritime economy. The province has adopted several regulations throughout the years that have opened new doors to successfully use land, water, forest, and marine resources for socio-economic development, yielding spectacular achievements. However, the overexploitation of resources along with intensive farming has damaged the ecosystem and polluted the environment. Besides, in the context of the general change of the Vietnamese Mekong Delta and Viet Nam, different opportunities and challenges have emerged, having a substantial influence on the long-term progress of the province. This article is to analyze the current situation and potential of exploiting natural resources for the expansion of Kien Giang's economy in terms of agriculture, forestry, fisheries, and marine economy, and recommends several future resource usage choices that sustain and enhance local ecosystem services.

The phenomenon of fruitless season during a period of the year is called "hanging coconut".  For the group of tall coconuts, it usually occurs from September to October, while for the group of dwarf coconuts, it usually occurs from March to April. Boron is required for pollen germination, pollen tube growth, and is essential for cell and seed formation. Research results on 2 coconut varieties: tall coconut (green sap, green ta), dwarf coconut (blue xiem, dark xiem, green xiem) grown in Long Duc commune, Tra Vinh city showed that the total germination rate of pollen grains were over 50% when adding boric acid 10 ppm in all 5 experimental coconut varieties at 36 hours after inoculation, increasing the concentration of boric acid supplement led to a decrease in pollen germination rate; however, there was only statistical difference between the supplementation concentrations in total pollen germination percentage in green sap and siam green coconuts. The concentration of boric acid didn’t spray affect the fruit setting rate of xiem coconuts when covered or not bloomed after 30 days of spraying. No inflorescence boss has a higher fruit set rate after 30 days than inflorescence boss.

This study aimed to investigate the efficacy of NPISi microbial product on growth and yield of green onion; and selected soil properties under greenhouse conditions. The NPISi microbial product was applied with three different levels including 80, 60, and 40 kg/ha in a combination with 100N-85P2O5-40K2O as recommended chemical fertilizer and 75% recommended chemical NP fertilizer (75N-63,75P2O5-40K2O). The results showed that the treatment applied with NPISi microbial product at 40 kg/ha in a combination with 75N-63,75P2O5-40K2O improved plant height, number of leaves, number of shoots/bush, stem diameter, length of stem and fresh biomass of green onion. Moreover, the addition of NPISi microbial product improved soil pH and EC, numbers of bacteria, nitrogen fixing bacteria, phosphate solubilizing bacteria and silicate solubilizing bacteria as compared to the recommended chemical fertilizer treatment without inoculation. Therefore, it is possible to exploit NPISi microbial product as a microbial fertilizer to increase green onion yield, reduce chemical fertilizers for safe and sustainable agricultural production.

This study was conducted to elucidate the coexistence mechanism of woody species in the broadleaved evergreen forest at Kon Ka Kinh National Park, Gia Lai province. All trees of three 1 ha-standard squares (100×100 m) with DBH (diameter at breast height) ≥ 2.5 cm were mapped and their characteristics (DBH and species name) were recorded. The study used the spatial point pattern analysis method to analyze the spatial distribution and association patterns of the main 20 species in three standard squares. Data were analyzed by using Programita Noviembre version 2018 and R version 4.1.1 software. The results showed that the spatial patterns of 12 species out of 20 analyzed species were aggregation patterns at small scales of < 15 m,  random and regular patterns tended to increase at large scales of > 15 m. Independent associations accounted for a high proportion (75-90%), while attractions and repulsions accounted for a low proportion (10-25%), the spatial association structure of species pairs was mainly independence or segregation patterns at scales of > 15 m. Dispersal limitation, environmental heterogeneity, and density dependence are three underlying mechanisms that control the spatial distribution, association patterns, and spatial association structure of woody species in the study area.

The study aimed to recycle the biogas digester to produce solid organic fertilizer and its effect on growth and yield of lettuce (Lactuca sativa) under greenhouse condition. Biogas effluents were absorbed into coal slag and mixed with a sugarcane filter at different ratios including 30:70, 20:80, 10:90 (%:%), then, fishmeal and beneficial bacteria were added. The results showed that the treatment of 30:70  together with 16.7% fishmeal and beneficial microorganisms met Vietnam's Organic Fertilizer Standards. Under greenhouse condition, the treatments received 1 to 5 tons/ha biogas fertilizer in a combination with reducing of 25% NP recommended helped to increase lettuce yield by 47 – 127%. In conclusion, the reuse of biogas effluent, coal slag, and sugarcane bagasse to produce solid organic fertilizer not only helped to increase crop yields but also save chemical fertilizers for environmental protection and sustainable agricultural development.

An investigation was conducted to access the prevalence of Marek’s disease virus (MDV) in backyard chicken flocks in Can Tho city. A total of 353 feather follicle samples were collected from 50 unvaccinated chicken flocks for Marek’s disease in Phong Dien, Co Do, Thoi Lai and Vinh Thanh districts. The confirmation of MDV infection was conducted by polymerase chain reaction to detect in specific Meq gene of the MDV serotype 1. The results showed that 26 out of 353 samples were positive for MDV accounting 7.37%. The prevalence of MDV in chickens in Phong Dien district was highest with 16.07%, followed by Co Do (8.60%), Thoi Lai (5.43%), and Vinh Thanh (3.57%) districts, and the different prevalence of MDV in chickens among Phong Dien, Thoi Lai and Vinh Thanh districts was significant (P

The survey was conducted in two phases, the first in 2015 and the second in 2020, with direct interviews conducted at mudcrab (Scylla paramamosain) hatcheries in three Mekong Delta provinces, including Bac Lieu, Ca Mau, and Kien Giang, to collect information on mudcrab hatchery production techniques and food use in mudcrab larvae rearing. The zoea1 larval density ranges between 101.6 and 192.7 larvae/m2. Survival rates for megalopa and crab 1 were 8.17 percent for megalopae and 6.74 percent for crab 1. The findings revealed that in the rearing of mub crab larvae, 100% of hatcheries used a combination of Artemia and artificial feed (for shrimp larvae). Protein content in feed ranges from 42 to 52%, with lipids ranging from 7 to 14.2 %. Artemia covered a large portion of the cost (75%) while artificial feed accounted for only 3 %. The production of mud crab larvae in the Mekong Delta is still heavily reliant on Artemia sources, and there is no formulated feed for mud crab rearing, so research on mud crab larvae rearing feed is required for mud crab hatcheries.

This study aimed to determine the diversity of species composition and densities of algae under the effects of different rice cultivation activities in Luong An Tra commune, Tri Ton district, An Giang province. Algal samples were collected at 6 sites in wetlands with 2 rice crops per year (group 1) and 3 rice crops per year (group 2). The results showed that a total of 95 species of algae belonging to 6 phyla were identified. Green algae had the highest species composition with 39 species, followed by Euglenoids and Diatoms (22 species for each), and others with 2-6 species. The species composition and mean density of algae during the study period varied from 57-86 species and 271,046±269,014 ind. L-1 to 655,219±305,233 ind. L-1, respectively. The total number of algal species in group 1 tended to be higher than that in group 2. However, the average density of group 2 was higher than that of group 1. The Shannon (H') and Simpson (D) diversity indexes ranged from 1.7 to 2.5 and from 0.7 to 0.9, respectively. The Pielou's evenness index (J') ranged from 0.4 to 0.7. The various rice cultivation modes affected the species composition and abundance of algae in the study area.

The Soc Trang - Bac Lieu coastal region is about 128 km long with four main estuaries including Tran De, My Thanh, Nha Mat, and Ganh Hao. The coastal fishes were investigated from 03/2018 to 01/2022 by trawl-net, stow-net, and gill-net boats. The results showed that there were 122 fishes identified belonging to 45 families of 17 orders. There were 64 species of the Perciformes (sharing 53.3% of the total) and the others were Clupeiformes with 15 fishes (12.3%), Pleuronectiformes with 11 fishes (9.02%); and other orders with only from 1 to 6 fishes (0.82 – 4.92%). Fish composition in different sampling sites of Soc Trang - Bac Lieu coastline was similar, but there was different number of species among the estuary areas in months of theyear, and in different years; the highest number of species was found in November (at Tran De and My Thanh estuaries) and in July (at Nha Mat estuary). There were some fishes rarely found such as Otolithoides biauritus, Scomberoides lysan, Netuma thalassina, and Leptomelanosoma indicum. The fish composition of Soc Trang and Bac Lieu coastal regions was diverse and rich.

The study was conducted to find out the appropriate ratio of artificial seawater for the culture of white leg shrimp (Litopenaeus vannamei). The study was conducted in 5 treatments with different ratios of artificial seawater and natural seawater including 100, 75, 50, 25, and  0% artificial seawater. Each treatment was repeated 4 times. The average initial size of shrimp was 3.18 ± 0.37 g in weight and 7.42 ± 0.17 cm in length; and the stocking density was 100 shrimp/m3. Shrimp were fed 5 times/day with 40% protein pellets. The results showed that the growth and survival rates of shrimp in 0 and 25% artificial seawater were significantly higher if  compared to those in 50, 75, and 100% artificial seawater; in which the growth and survival rates of shrimp in 100% artificial seawater were the lowest. Thus, artificial seawater can be used to replace natural seawater at the ratio of 25% in culture of white leg shrimp.

This study was conducted to evaluate the effects of different nutrient supplementations on the growth and agar quality of red seaweed (Gracillaria tenuistipitata) in laboratory conditions. Six different nutrient supplementation treatments were randomly assigned in triplicate. The control treatment was not supplemented with nutrients. The remaining five treatments were supplemented with 5, 10, 15, 20, and 25 g/m3 weekly, using inorganic fertilizers (urea and DAP, ratio N:P = 10:1). The initial biomass of seaweed was 2 g/L at a salinity of 15 ‰. After 30 days, the biomass and growth of seaweed in treatments of 15 and 20 g/m3 reached the highest values and decreased at the supplement level of 25 g/m3. The yields and gel strength of agar were highest in the control treatment and lowest in the 25 g/m3 treatment, while the viscosity in the control treatment was the lowest. Gelling temperature and melting temperature of agar were not statistically significant (p > 0.05) among the levels of nutrient supplementation. In addition, the protein content of seaweed positively correlated with the increase of nutrient supplementations, whereas the gel strength of agar negatively correlated with the protein content of red seaweed.

The study's purpose was to see if it was possible to substitute formulated feed (FF) for Artemia when rearing mub crab Scylla paramamosain larvae from Zoe 3 to crab 1. There were two experiments (i) rearing from the Zoe 3 to the megalop stage and megalop stage. 1. In each experiment, ware included 6 treatments, with 5 replications. Mubcrab lavae was fed  5-times/day for all treatments; the control treatment was completely fed Artemia, whereas the formulated feed (FF) treatment completely replaced Artemia. Artemia was replaced 1 to 4 times with processed food in the remaining four treatments. The results showed that survival rates of zoae 5 and megalopa tended to increase gradually with the rate of Artemia feeding, averaging 30.8-91.1%and 8.6-17.0%, respectively, in which treatment 3, 4, and 5 times Artemia/day did not differ statistically. The survival rate from megalopa to crab 1 ranged from 57.6 to 76.8%, with formulated feed being the most effective treatment. Artemia can be reduced by 40% from Zoea3 to Megalopa stage, and up to 100% from Megalopa to stage crab 1.

The study is aimed to identify which factors affect public servants and officers’ satisfaction, motivation, and work engagement. The quantitative approach was applied with data collection from 320 public servants and officers representing 25,583 public jobholders in Ben Tre province and PLS-SEM was used to test the hypotheses. The findings indicated that six factors including job content, job satisfaction, work motivation, rights and responsibilities, working environment and relationship with colleagues have direct impacts on work engagement; six factors including relationship with leader, rights and responsibilities, job content, income, working environment and welfare have indirect impacts on work engagement. Among competences, three factors including job content, rights and responsibilities, working environment have direct and indirect on work engagement.

This study was based on theories related to satisfaction, motivation, job performance and empirically examined the relationships between these factors. A quantitative method was applied by directly delivering a questionnaire to 510 officials, civil servants and public employees in Ben Tre province. SmartPLS software and PLS - SEM statistical techniques were used to test hypotheses, measure scales, and structural models. Research results showed that training need assessment, training content, training methods, training commitment, job satisfaction, and work motivation directly and/or indirectly affect job performance. Thus, it is recommended that governmental organizations, before and after the cooperation of human resource training with universities and training centers, need proper assessments of their training needs and the trainees’ additional assessments of the training contents and methods to accumulate experiences for future training programs.

This paper is aimed to investigate the current situation of working part-time and its impacts on the academic and non-academic activities of the students from Cohort 43 to Cohort 45 of the School of Foreign Languages, Can Tho University. A survey of 275 students with part-time work experience reveals that this was a fairly popular activity among students and had an impact on their lives. The results showed that (1) working part-time had more positive effects on non-academic activities than academic ones; (2) it also caused a moderate negative effect on daily life and study activities, with the most negative effect on personal life; (3) the more time students spent on working part-time (2 hours/day or more), the more negative effects students had on academic and non-academic activities, particularly on their health. The solutions that the participants had applied to limit the negative effects of part-time work on their life are also reported.