Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0008
Thuy Le Thi, Na Nguyen Thi, Tuoi Le Thi, Viet Nguyen Xuan
The study aimed to isolate and purify the pathogenic fungal strains isolated from blight disease taro leaves in some provinces of Northern Vietnam, from which to select the pathogenic strains belonging to Phytophthora colocasiae species, and to determine their toxicity on taro plants. From leaf tissue showing leaf blight collected from taro fields in 6 places in Bac Giang, Bac Ninh, Hanoi, and Hoa Binh provinces, 6 strains of the fungus were isolated. Based on the morphological characteristics as well as ITS rDNA sequences, it was confirmed that two of the six strains were Phytophthora colocasiae and named BN1 and SB, respectively. The sporangium of strain BN1 was ovoid and strain SB was a semi-papillary spherical shape. Both fungal strains grew well on CGA and PGA media and had equivalent toxicity through in vitro infection testing on 3 taro gene sources.
{"title":"Isolation and pathogenicity evaluation of Phytophthora colocasiae causing leaf blight disease in taro (Colocasia esculenta L. Schott) in some Northern provinces, Vietnam","authors":"Thuy Le Thi, Na Nguyen Thi, Tuoi Le Thi, Viet Nguyen Xuan","doi":"10.18173/2354-1059.2023-0008","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0008","url":null,"abstract":"The study aimed to isolate and purify the pathogenic fungal strains isolated from blight disease taro leaves in some provinces of Northern Vietnam, from which to select the pathogenic strains belonging to Phytophthora colocasiae species, and to determine their toxicity on taro plants. From leaf tissue showing leaf blight collected from taro fields in 6 places in Bac Giang, Bac Ninh, Hanoi, and Hoa Binh provinces, 6 strains of the fungus were isolated. Based on the morphological characteristics as well as ITS rDNA sequences, it was confirmed that two of the six strains were Phytophthora colocasiae and named BN1 and SB, respectively. The sporangium of strain BN1 was ovoid and strain SB was a semi-papillary spherical shape. Both fungal strains grew well on CGA and PGA media and had equivalent toxicity through in vitro infection testing on 3 taro gene sources.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72938018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0006
Hong Nguyen Thi, Long Tran Hai, Kien Do Trung
This study aims to identify the factors that influence academic performance and use them to develop a predictive model for student academic achievement, in order to support the improvement of education quality. In previous studies, the selection and evaluation of factors were only conducted on online learning data. In this study, we propose using a selected set of attributes from experimental data collected both in face-to-face classes and on the online learning system at Hanoi National University of Education. To build the predictive model for academic performance, we employed two variable selection methods: one is to choose highly correlated variables, and the other is to use the Stepwise linear regression analysis. Furthermore, two machine learning algorithms, linear regression, and support vector regression were used to construct the predictive model. The experimental results show that the support vector regression model with a polynomial kernel function built from the Stepwise-selected variables is the most effective.
{"title":"Using machine learning to identify influential factors and predict student academic performance in blended learning","authors":"Hong Nguyen Thi, Long Tran Hai, Kien Do Trung","doi":"10.18173/2354-1059.2023-0006","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0006","url":null,"abstract":"This study aims to identify the factors that influence academic performance and use them to develop a predictive model for student academic achievement, in order to support the improvement of education quality. In previous studies, the selection and evaluation of factors were only conducted on online learning data. In this study, we propose using a selected set of attributes from experimental data collected both in face-to-face classes and on the online learning system at Hanoi National University of Education. To build the predictive model for academic performance, we employed two variable selection methods: one is to choose highly correlated variables, and the other is to use the Stepwise linear regression analysis. Furthermore, two machine learning algorithms, linear regression, and support vector regression were used to construct the predictive model. The experimental results show that the support vector regression model with a polynomial kernel function built from the Stepwise-selected variables is the most effective.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85481497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0013
Khanh Uong Dinh, Son Hoang Thanh, Lan Vu Thi Thu, Tuan Bui Anh, Hanh Le Duc, Dang Vu Hai, Quang Trinh Xuan, Tuan Tong Phuc
Riverbank erosion is increasingly causing negative impacts on the socio-economic development of Quang Nam province. The riverbank accretion-erosion is a natural phenomenon, reflecting the certain relationship between the flow and the channel’s characteristics through the sediment balance. Forecasting the evolution of erosion and accretion plays an important role in the sustainable development of the communities, agricultural sector as well as other sectors on both sides of the river in particular and the whole region in general. This paper presents the results of applying a set of MIKE models (MIKE11RR, HD, ST, and MIKE 21C) to simulate river bank evolution (erosion, accretion) under scenarios with 1%, 2%, 5%, and 10% flood frequencies. Comparison with the river’s bank changes in reality has shown that the simulation ability of the model is reliable enough, and suitable for the specific conditions of the Vu Gia - Thu Bon River basin. Calculation results have been mapped on the risk of riverbank erosion corresponding to flood frequency levels, and the model set also allows to extraction of accompanying information, which is the scientific basis for proposing adaptive solutions and damage reduction.
{"title":"Vu Gia - Thu Bon River bank erosion assessment (Quang Nam province) based on MIKE 21c model","authors":"Khanh Uong Dinh, Son Hoang Thanh, Lan Vu Thi Thu, Tuan Bui Anh, Hanh Le Duc, Dang Vu Hai, Quang Trinh Xuan, Tuan Tong Phuc","doi":"10.18173/2354-1059.2023-0013","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0013","url":null,"abstract":"Riverbank erosion is increasingly causing negative impacts on the socio-economic development of Quang Nam province. The riverbank accretion-erosion is a natural phenomenon, reflecting the certain relationship between the flow and the channel’s characteristics through the sediment balance. Forecasting the evolution of erosion and accretion plays an important role in the sustainable development of the communities, agricultural sector as well as other sectors on both sides of the river in particular and the whole region in general. This paper presents the results of applying a set of MIKE models (MIKE11RR, HD, ST, and MIKE 21C) to simulate river bank evolution (erosion, accretion) under scenarios with 1%, 2%, 5%, and 10% flood frequencies. Comparison with the river’s bank changes in reality has shown that the simulation ability of the model is reliable enough, and suitable for the specific conditions of the Vu Gia - Thu Bon River basin. Calculation results have been mapped on the risk of riverbank erosion corresponding to flood frequency levels, and the model set also allows to extraction of accompanying information, which is the scientific basis for proposing adaptive solutions and damage reduction.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87953571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0014
Duong Dinh Hoang, Thanh Do Van, Hoan Kieu Van, Loi Duong Thi, Nhung To Thi Hong
The objective of this paper is to analyze the characteristics of the factors that make up the landscape. These factors are the basis for the establishment of landscape maps and landscape assessment for planning as well as sustainable development of agriculture, forestry, and tourism in Ba Be district, Bac Kan province. This is a locality that has attracted great attention from domestic and foreign scientists because it holds the great value of natural resources. The task of establishing landscape maps and landscape classification systems based on factors such as geology, topography, climate, soil, vegetation, etc., is a scientific foundation for regulation. planning and sustainable development of agriculture, forestry, and tourism for this study area.
{"title":"Characteristics of the factors forming the landscape of Ba Be district, Bac Kan province","authors":"Duong Dinh Hoang, Thanh Do Van, Hoan Kieu Van, Loi Duong Thi, Nhung To Thi Hong","doi":"10.18173/2354-1059.2023-0014","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0014","url":null,"abstract":"The objective of this paper is to analyze the characteristics of the factors that make up the landscape. These factors are the basis for the establishment of landscape maps and landscape assessment for planning as well as sustainable development of agriculture, forestry, and tourism in Ba Be district, Bac Kan province. This is a locality that has attracted great attention from domestic and foreign scientists because it holds the great value of natural resources. The task of establishing landscape maps and landscape classification systems based on factors such as geology, topography, climate, soil, vegetation, etc., is a scientific foundation for regulation. planning and sustainable development of agriculture, forestry, and tourism for this study area.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78607047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0012
M. Tran Thi, Thuy Hoang Luu Thu, Vu Vuong Van, Huong Do Thi Van, Ha Dang Thi Ngan
The paper aims to assess the changing trend of monthly rainfall and minimum monthly rainfall in Binh Dinh province by the Mann-Kendall test method and the Theil-Sen trend in the period 1981 - 2919. The results show that: With a statistical significance of 5%, rainfall tends to increase in January at Hoai Nhon and Binh Tuong stations with an increase of 1.2 - 1.3 mmyear and tends to increase in August at An Nhon station with an increase of 1.7 mmyear but tends to decrease in June at Quy Nhon station with a decrease of 1.6 mmyear. The total rainfall in the minimum months (from January to April) tends to increase at Hoai Nhon and Quy Nhon stations with an increase of 2.3 - 2.5 mmyear. Monthly rainfall and total monthly rainfall at the remaining stations do not satisfy the condition P-value ≤ 0.05, therefore, hypothesis H0 is accepted as a trendless series.
{"title":"Research assessment variation trend of precipitation in Binh Dinh province by Mann-Kendall test and Theil-Sen trend","authors":"M. Tran Thi, Thuy Hoang Luu Thu, Vu Vuong Van, Huong Do Thi Van, Ha Dang Thi Ngan","doi":"10.18173/2354-1059.2023-0012","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0012","url":null,"abstract":"The paper aims to assess the changing trend of monthly rainfall and minimum monthly rainfall in Binh Dinh province by the Mann-Kendall test method and the Theil-Sen trend in the period 1981 - 2919. The results show that: With a statistical significance of 5%, rainfall tends to increase in January at Hoai Nhon and Binh Tuong stations with an increase of 1.2 - 1.3 mmyear and tends to increase in August at An Nhon station with an increase of 1.7 mmyear but tends to decrease in June at Quy Nhon station with a decrease of 1.6 mmyear. The total rainfall in the minimum months (from January to April) tends to increase at Hoai Nhon and Quy Nhon stations with an increase of 2.3 - 2.5 mmyear. Monthly rainfall and total monthly rainfall at the remaining stations do not satisfy the condition P-value ≤ 0.05, therefore, hypothesis H0 is accepted as a trendless series.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75120964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0003
Hoc Nguyen Quang, Uyen Pham Phuong, Thanh Pham Duy, V. Le Hong
The article presents the theory of elastic deformation and elastic wave propagation velocity of BCC binary interstitial alloy’s thin film based on the statistical moment method. Metal’s films and bulk interstitial alloys are specific cases of interstitial alloy’s films in this theory. The obtained theoretical results are applied to W and WSi films, where calculated results are compared with other calculations and experimental data.
{"title":"Study on the elastic deformation of BCC interstitial alloy’s thin film","authors":"Hoc Nguyen Quang, Uyen Pham Phuong, Thanh Pham Duy, V. Le Hong","doi":"10.18173/2354-1059.2023-0003","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0003","url":null,"abstract":"The article presents the theory of elastic deformation and elastic wave propagation velocity of BCC binary interstitial alloy’s thin film based on the statistical moment method. Metal’s films and bulk interstitial alloys are specific cases of interstitial alloy’s films in this theory. The obtained theoretical results are applied to W and WSi films, where calculated results are compared with other calculations and experimental data.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74556225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0002
Duc Nguyen Anh, Xuan Dieu Nguyen Thi
In this report, we present the synthesis of low dimensional shell-core (2D1D) nanostructures, in which the TiO2 nanorods (TNRs) as the core are covered by a continuous monolayer MoS2 (1L-MoS2) as the shell. The obtain 1L-MoS2TNRs was directly grown on the conduct graphite foil without any transfer process, thus minimizing the charge transfer resistance from the electrode to the outer most working surface. For the first steps, the TiO2 seed layer was designed by the AF sputtering method, then the TNRs were grown by hydrothermal approach. Thereafter, the TNRs were conformally coated by a continuous monolayer MoS2 via a metal-organic chemical vapor deposition technique, resulting in 1L-MoS2TNRs nanomaterial. The structural, vibrational, and morphological characteristics demonstrated that the samples are high crystallinity. Interestingly, the 1L-MoS2TNRs showed highly efficient in electrochemical HER activity with the smallest onset overpotential of -140 mV vs RHE and a corresponding Tafel slope of 80 mV per decade, which were much lower compared to the pristine 1L-MoS2 and TNRs.
{"title":"Controlled synthesis of low-dimensional MoS2TiO2 based core-shell structure for hydrogen evolution reaction","authors":"Duc Nguyen Anh, Xuan Dieu Nguyen Thi","doi":"10.18173/2354-1059.2023-0002","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0002","url":null,"abstract":"In this report, we present the synthesis of low dimensional shell-core (2D1D) nanostructures, in which the TiO2 nanorods (TNRs) as the core are covered by a continuous monolayer MoS2 (1L-MoS2) as the shell. The obtain 1L-MoS2TNRs was directly grown on the conduct graphite foil without any transfer process, thus minimizing the charge transfer resistance from the electrode to the outer most working surface. For the first steps, the TiO2 seed layer was designed by the AF sputtering method, then the TNRs were grown by hydrothermal approach. Thereafter, the TNRs were conformally coated by a continuous monolayer MoS2 via a metal-organic chemical vapor deposition technique, resulting in 1L-MoS2TNRs nanomaterial. The structural, vibrational, and morphological characteristics demonstrated that the samples are high crystallinity. Interestingly, the 1L-MoS2TNRs showed highly efficient in electrochemical HER activity with the smallest onset overpotential of -140 mV vs RHE and a corresponding Tafel slope of 80 mV per decade, which were much lower compared to the pristine 1L-MoS2 and TNRs.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"14 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83435154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0015
Khac Dang Vu
The mangrove palm grows at the Thu Bon river’s mouth. Mangrove palm has contributed to the conservation of natural ecosystems, and the biological diversity of Cu Lao Cham – Hoi An Biosphere Reserve, as well as the socio-economic development of Hoi An city. However, in recent year, its coverage has been gradually reduced due to human socio-economic activities. This study has used not only the raw bands of the Sentinel-2A image but also some spectral indices have been calculated via the band ratio for classifying land covers. The principal component analysis (PCA) was applied to these all bands to eliminate redundant and noise contributions in data. Mangrove palm was separated from other land cover categories with an object-based image classification approach using Support Vector Machines (SVMs) algorithm because of its high efficiency, performance, and flexibility. The obtained map indicates that mangrove palm principally distributes on the left bank of Thu Bon River with a total area of 147 ha by 2019. The validation, was realized by comparing the classification results with random samples through the visual interpretation of Google Earth high resolution image. The error assessment shows that the overall accuracy is about 88.67% and the Kappa coefficient reaches 0.84. Although there are some differences related to the spatial resolution of Sentinel-2 images, such obtained results may support authorities in decision-making by providing maps able to suggest necessary responses for the conservation of mangrove palms this coastal area.
{"title":"Detection of mangrove palm coverage at Cu Lao Cham-Hoi An Biospherer reserve using Sentinel-2A data","authors":"Khac Dang Vu","doi":"10.18173/2354-1059.2023-0015","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0015","url":null,"abstract":"The mangrove palm grows at the Thu Bon river’s mouth. Mangrove palm has contributed to the conservation of natural ecosystems, and the biological diversity of Cu Lao Cham – Hoi An Biosphere Reserve, as well as the socio-economic development of Hoi An city. However, in recent year, its coverage has been gradually reduced due to human socio-economic activities. This study has used not only the raw bands of the Sentinel-2A image but also some spectral indices have been calculated via the band ratio for classifying land covers. The principal component analysis (PCA) was applied to these all bands to eliminate redundant and noise contributions in data. Mangrove palm was separated from other land cover categories with an object-based image classification approach using Support Vector Machines (SVMs) algorithm because of its high efficiency, performance, and flexibility. The obtained map indicates that mangrove palm principally distributes on the left bank of Thu Bon River with a total area of 147 ha by 2019. The validation, was realized by comparing the classification results with random samples through the visual interpretation of Google Earth high resolution image. The error assessment shows that the overall accuracy is about 88.67% and the Kappa coefficient reaches 0.84. Although there are some differences related to the spatial resolution of Sentinel-2 images, such obtained results may support authorities in decision-making by providing maps able to suggest necessary responses for the conservation of mangrove palms this coastal area.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80165357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0011
Hung Dao Ngoc, Chi Le Hanh, Chien Nguyen Quyet, Phuong Cu Thi, Hiền Nguyễn Thị Thu, Hien Vu Thuc
This study was based on heat index (HI) to determine risk thresholds for warning heat stress to communities in Ninh Binh City. The study used correlation evaluation and regression equations, meteorological data for the period 1991 - 2021, and Vietnam climate change scenario data to calculate the maximum daily heat index (HImax) scenario for the country in the period 2024 - 2054. The results showed that, in the future, the trend of HImax will increase by 0.100 °C per year under the RCP 4.5 scenario (Medium Low greenhouse gases concentration scenario) and 0.105 °C per year under the RCP 8.5 scenario (High greenhouse gases concentration scenarios). The number of HImax days at dangerous levels will increase by about 1 day per year with both RCP 4.5 and RCP 8.5 scenarios. In particular, the number of HImax days at extreme danger levels, with the risk of causing stroke, in the period 2024 - 2054 appeared more than before, especially in the period 1941 - 2054, the trend increased sharply. In some last years of this period, the number of HImax days will be extremely dangerous up to 20 - 30 days.
{"title":"Assessment of the variation on maximum daily heat index in Ninh Binh city","authors":"Hung Dao Ngoc, Chi Le Hanh, Chien Nguyen Quyet, Phuong Cu Thi, Hiền Nguyễn Thị Thu, Hien Vu Thuc","doi":"10.18173/2354-1059.2023-0011","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0011","url":null,"abstract":"This study was based on heat index (HI) to determine risk thresholds for warning heat stress to communities in Ninh Binh City. The study used correlation evaluation and regression equations, meteorological data for the period 1991 - 2021, and Vietnam climate change scenario data to calculate the maximum daily heat index (HImax) scenario for the country in the period 2024 - 2054. The results showed that, in the future, the trend of HImax will increase by 0.100 °C per year under the RCP 4.5 scenario (Medium Low greenhouse gases concentration scenario) and 0.105 °C per year under the RCP 8.5 scenario (High greenhouse gases concentration scenarios). The number of HImax days at dangerous levels will increase by about 1 day per year with both RCP 4.5 and RCP 8.5 scenarios. In particular, the number of HImax days at extreme danger levels, with the risk of causing stroke, in the period 2024 - 2054 appeared more than before, especially in the period 1941 - 2054, the trend increased sharply. In some last years of this period, the number of HImax days will be extremely dangerous up to 20 - 30 days.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87226407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.18173/2354-1059.2023-0010
Khac Dang Vu
For a long time, many pixel-based image classification algorithms have been developed for identifying land cover, some of which are commonly used due to their efficiency and accuracy such as Maximum Likelihood (MLC), Support Vector Machines (SVMs), and Decision Trees (DTs). These methods are applied to classify land cover in Ha Long city using Landsat-8 satellite images with several categories including residence, bare soil, forest, agricultural land, water surface, and coal field. The validation results show that the overall accuracy (OA) and Kappa coefficient (K) of these classification methods are high, with OA > 91 % and K > 0.9. However, compared to the other two methods, the DTs method provides the results with the highest accuracy and the best ability to separate features. The obtained results allow selecting the image classification method for identical areas with complicated land cover such as Ha Long.
长期以来，人们开发了许多基于像素的图像分类算法来识别土地覆盖，其中一些算法由于其效率和准确性而被广泛使用，如最大似然(MLC)、支持向量机(svm)和决策树(dt)。利用这些方法，利用Landsat-8卫星影像对下龙市土地覆盖进行了住宅、裸地、森林、农地、水面、煤田等分类。验证结果表明，这些分类方法的总体准确率(OA)和Kappa系数(K)较高，OA > 91%， K > 0.9。然而，与其他两种方法相比，dt方法提供的结果具有最高的准确性和最好的特征分离能力。所得结果可为下龙等具有复杂地表覆盖的相同区域选择图像分类方法。
{"title":"Comparison of image classification methods to establishing land cover map at Ha Long city, Quang Ninh province using the Landsat-8 images","authors":"Khac Dang Vu","doi":"10.18173/2354-1059.2023-0010","DOIUrl":"https://doi.org/10.18173/2354-1059.2023-0010","url":null,"abstract":"For a long time, many pixel-based image classification algorithms have been developed for identifying land cover, some of which are commonly used due to their efficiency and accuracy such as Maximum Likelihood (MLC), Support Vector Machines (SVMs), and Decision Trees (DTs). These methods are applied to classify land cover in Ha Long city using Landsat-8 satellite images with several categories including residence, bare soil, forest, agricultural land, water surface, and coal field. The validation results show that the overall accuracy (OA) and Kappa coefficient (K) of these classification methods are high, with OA > 91 % and K > 0.9. However, compared to the other two methods, the DTs method provides the results with the highest accuracy and the best ability to separate features. The obtained results allow selecting the image classification method for identical areas with complicated land cover such as Ha Long.","PeriodicalId":17007,"journal":{"name":"Journal of Science Natural Science","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81391139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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