152 research outputs found

    EVALUATION OF SOLAR RADIATION ESTIMATED FROM HIMAWARI-8 SATELLITE OVER VIETNAM REGION

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    The development of Solar energy system is growing rapidly in Vietnam in recent years by encouragement of the Government in renewable energy. Requirement for accurate knowledge of the solar radiation reaching the surface is increasingly important in the successful deployment of Solar photovoltaic plants. However, measurements of different components of solar resources including direct normal irradiance (DNI) and global horizontal irradiance (GHI) are limited to few stations over whole country. Satellite imagery provides an ability to monitor the surface radiation over large areas at high spatial and temporal resolution as alternatives at low cost. Observations from the new Japanese geostationary satellite Himawari-8 produce imagery covering Asia-Pacific region, permitting estimation of GHI and DNI over Vietnam at 10-minute temporal resolution. However, accurate comparisons with ground observations are essential to assess their uncertainty. In this study, we evaluated the Himawari-8 radiation product AMATERASS provided by JST/CREST TEEDDA using observations recorded at 5 stations in different regions of Vietnam. The result shows good agreement between satellite estimation and observed data with high correlation of range 0.92-0.94, but better in clear-sky episodes.Because of AMATERASS outperform, we used it for validating ERA-Interim reanalysis in the spatial scale. The comparison was made dividedly for 7 climate zones and 4 seasons. The conclusion is that ERA-Interim is also well associated with satellite-based estimates in seasonal trend for all season, but in average the reanalysis has negative bias towards satellite estimates. This underestimation is more pronounced in the months of JJA and SON periods and in the north part of Vietnam because of unpredicted cloud in the ERA reanalysis

    Entrepreneurial Finance: Insights from English Language Training Market in Vietnam

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    Entrepreneurship plays an indispensable role in the economic development and poverty reduction of emerging economies like Vietnam. The rapid development of technologies during the Fourth Industrial Revolution (Industry 4.0) has a significant impact on business in every field, especially in the innovation-focused area of entrepreneurship. However, the topic of entrepreneurial activities with technology applications in Vietnam is under-researched. In addition, the body of literature regarding entrepreneurial finance tends to focus on advanced economies, while mostly neglecting the contextual differences in developing nations. Therefore, this research contributes to these topics by investigating the main characteristics of a high potential market for entrepreneurs in Vietnam, which is the English language training market (ELTM). It also aims at indicating the impacts of technology on the entrepreneurial firms within this market, with an emphasis on financing sources. To answer the research questions, this study employs a qualitative analysis and conducts 12 in-depth, semi-structured interviews with entrepreneurs and researchers in the field. The key findings in our study highlight the main contributing factors to the growth of the market, both universally and context-specific for a developing nation like Vietnam. It also lists the leaders in each market segment and the industry’s potential profit margin. The results also show that most entrepreneurs in the ELTM utilized private sources of finance rather than external ones, such as bank loans. It again confirms the idea from previous works that even with the rapid development of the economic and technological landscape, entrepreneurial activities in general barely benefit from additional sources of funding. However, it also points out the distinct characteristics of the ELTM that may influence these financing issues; for example, English training services usually collect revenues from customers before delivering their classes. This is of advantage for entrepreneurs in this area and helps significantly reduce the financial barriers. These findings, which are among the first attempts to contribute to a better understanding of entrepreneurial opportunities in the Industry 4.0 in Vietnam, provide valuable insights for policymakers and entrepreneurs, as well as investors

    Antibacterial activity of Piper betle extracts on Helicobacter pylori and identification of potential compounds

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    Helicobacter pylori is one of the most common infectious bacteria in the world that causes gastric diseases leading to cancer. The increase of multiple antibiotic resistance rates of H. pylori have been reported worldwide. Thus, development of novel drugs is urgently required. Piper betle has many therapeutic values in traditional medicine. In this study, therefore, we investigated antibacterial activity of P. betle extracts and their fractions against a H. pylori strain isolated in Vietnam. The agar disk diffusion assay showed inhibition zone of ethyl acetate extract and methanol extract from P. betle leaf that of were 46 mm and 32 mm in diameter, respectively. After fractionation of the ethyl acetate extract through silica gel column chromatography, two peaks, PD2 and PD3, out of 12 fractions showed the strongest antibacterial activity. PD2 was sub-fractionated further by re-chromatography on the silica gel column, and subfraction TK12 gave best resolution on LC-MS analysis. Finally, 4 potential compounds, quercetrin, calodenin B, vitexin and plicatipyrone, were identified in TK12 fraction.

    EVALUATION OF THE VULNERABILITY OF THE COASTAL SOCIO-NATURAL SYSTEMS (EXAMPLE FROM KHANH HOA COASTAL ZONE)

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    Joint Research on Environmental Science and Technology for the Eart

    Factors Affecting Young Consumers’ Intention to Purchase Upcycled Fashion Products – A Case Study in Vietnam

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    In this study, the author has given different basis to build hypothesis and research models to find out the factors affecting the Vietnamese young consumer's intention to purchase upcycled fashion products. Firstly, this paper focuses on studying the relationship between attitudes and purchase intentions. Secondly, the author studies the effects of factors on attitudes and purchase intentions. The main research subjects are factors affecting Vietnamese young consumer' intention to to purchase upcycled fashion products. Hence, this research was conducted based on survey results among 400 young people aged 18 to 34 in Hanoi and Ho Chi Minh city which are two big city in Vietnam. The authors used two statistical software, SPSS 26.0 and AMOS 20.0, to analyze the survey results. These tools help the authors analyze Cronbach's Alpha reliability coefficients, exploratory factor analysis (EFA), confirmatory factor analysis (CFA), structural equation model (SEM). The results show that there was a positive relationship between young consumers' attitudes and purchase intention in the Vietnamese context. Attitude mediates the relationship between the influencing factors and purchase intention. Moreover, the study test the impact of five main factors including environmental concern, social value, uniqueness value, perception financial risk, and perceive quality risk. The environmental concern (β = 0.337) is considered as the strongest effect on consumers' attitudes towards products. The factors such as uniqueness value (β = 0.302) as well as social value (β = 0.216) also positively affect consumers' attitudes. On the other hand, perception financial risk (β = -0.168), and perceive quality risk (β = -0.280) negatively affect consumers' attitude

    Potential mitigation contribution from coffee agroforestry in three regions of Viet Nam

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    Coffee agroforestry is one of the main agroforestry systems in Viet Nam in terms of total land area in the country, potential economic contribution, and ecosystem services provided by the shading tree species in the system. This report presents the results of a study that aimed to estimate potential mitigation contribution from carbon storage from coffee agroforestry systems in the three regions of the country. The estimated C storage of arabica coffee systems in the Northwest region of Viet Nam ranges from 2.6 to 17.0 ton ha-1. Potential storage at province level reaches 246,224 ton in Son La province, as it has a higher total area of coffee plantations than Dien Bien province. In the Southeast and Central Highlands region, the estimated C storage of robusta and arabica coffee agroforestry systems ranges from 5.8 to 10.4 ton ha-1, in general due to variation in shading tree species and density. The potential C storage at province level can reach up to 2.1 million ton as in the case of Dak Lak province. From local interviews with provincial authorities and smallholder farmers in the three regions, stakeholders could see the economic and environmental benefits that can be derived from the coffee agroforestry systems. However, the lack of knowledge in planting design and plot management options constrain farmers from transforming their coffee monoculture into agroforestry systems, or expanding the system into available areas for coffee cultivation. We recommend that the provincial authorities keep supporting and encouraging research on coffee agroforestry and provide reliable technical guidance for farmers to develop coffee agroforestry systems with appropriate design

    Data-Driven Construction Safety Information Sharing System Based on Linked Data, Ontologies, and Knowledge Graph Technologies

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    Accident, injury, and fatality rates remain disproportionately high in the construction industry. Information from past mishaps provides an opportunity to acquire insights, gather lessons learned, and systematically improve safety outcomes. Advances in data science and industry 4.0 present new unprecedented opportunities for the industry to leverage, share, and reuse safety information more efficiently. However, potential benefits of information sharing are missed due to accident data being inconsistently formatted, non-machine-readable, and inaccessible. Hence, learning opportunities and insights cannot be captured and disseminated to proactively prevent accidents. To address these issues, a novel information sharing system is proposed utilizing linked data, ontologies, and knowledge graph technologies. An ontological approach is developed to semantically model safety information and formalize knowledge pertaining to accident cases. A multi-algorithmic approach is developed for automatically processing and converting accident case data to a resource description framework (RDF), and the SPARQL protocol is deployed to enable query functionalities. Trials and test scenarios utilizing a dataset of 200 real accident cases confirm the effectiveness and efficiency of the system in improving information access, retrieval, and reusability. The proposed development facilitates a new “open” information sharing paradigm with major implications for industry 4.0 and data-driven applications in construction safety management

    How Digital Natives Learn and Thrive in the Digital Age: Evidence from an Emerging Economy

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    As a generation of ‘digital natives,’ secondary students who were born from 2002 to 2010 have various approaches to acquiring digital knowledge. Digital literacy and resilience are crucial for them to navigate the digital world as much as the real world; however, these remain under-researched subjects, especially in developing countries. In Vietnam, the education system has put considerable effort into teaching students these skills to promote quality education as part of the United Nations-defined Sustainable Development Goal 4 (SDG4). This issue has proven especially salient amid the COVID−19 pandemic lockdowns, which had obliged most schools to switch to online forms of teaching. This study, which utilizes a dataset of 1061 Vietnamese students taken from the United Nations Educational, Scientific, and Cultural Organization (UNESCO)’s “Digital Kids Asia Pacific (DKAP)” project, employs Bayesian statistics to explore the relationship between the students’ background and their digital abilities. Results show that economic status and parents’ level of education are positively correlated with digital literacy. Students from urban schools have only a slightly higher level of digital literacy than their rural counterparts, suggesting that school location may not be a defining explanatory element in the variation of digital literacy and resilience among Vietnamese students. Students’ digital literacy and, especially resilience, also have associations with their gender. Moreover, as students are digitally literate, they are more likely to be digitally resilient. Following SDG4, i.e., Quality Education, it is advisable for schools, and especially parents, to seriously invest in creating a safe, educational environment to enhance digital literacy among students

    Potential mitigation contribution from agroforestry to Viet Nam’s NDC

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    Viet Nam is among the 196 Parties in the Paris Agreement that has committed to low-emission development pathways. The country has formulated national climate change mitigation strategies that relate to forestry and agricultural sector, with a potential revision in 2019 that can include agroforestry (AF), provided that the potential mitigation contribution from this sector can be monitored and reported. This paper presents two approaches to measurement and reporting of AF, based on potential expansion domain (PED) of main AF systems in different regions across the country and the spatial distribution of trees outside forests (TOF), to estimate the potential mitigation contribution from AF, represented by total aboveground carbon (C) sequestration at national scale. Based on the PED approach, the total PED area of different AFs such as coffee, rubber or acacia-based, not including natural forest lands, is ≈10.1 million ha, or about 1/3 of the total land area in the country. Assuming the baseline land uses in the PED can be classified as “cultivated and managed lands,” which according to the Intergovernmental Panel on Climate Change (IPCC) has an average C stock 5 ton ha-1, expansion of the main AF systems across the country results in 262 ± 77 million tons of sequestered C per year, for ten years after plantation. The related total establishment cost for the expansion is USD 24.3 ± 11.3 billion. Using the TOF approach to estimate total tree coverage outside natural forest lands in 2010, total C storage of AF in Viet Nam is ≈355 million ton C, with an average of ≈21.8 ton C ha-1 from ≈20 million ha or about 2/3 of the total land area in the country. Comparing the PED and TOF approach under similar land coverage area of ≈10.1 million ha, the latter estimates a total C storage of ≈ 220 million ton C. By assuming it as total baseline C storage for the PED approach, the potential C gain from AF expansion is ≈92 million ton C, compared to ≈262 million ton C under the assumption of 5 ton ha-1 as average C stock for baseline land uses. This potential mitigation contribution from AF can be reported to relevant authorities, such as the Ministry of Agriculture and Rural Development (MARD) and its sub-institutions, that have a mandate to revise the potential mitigation contribution from the Agriculture and Land Use, Land Use Change, and Forestry sector to the country’s Nationally Determined Contribution (NDC). The challenges in integrating the potential contribution from AF to the agriculture sector or land use sector that focuses on forestry, or as a segregated land use category, should be further discussed with the relevant authorities

    STEM education and outcomes in Vietnam: Views from the social gap and gender issues

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    United Nations’ Sustainable Development Goals 4 Quality Education has highlighted major challenges for all nations to ensure inclusive and equitable quality access to education, facilities for children, and young adults. The SDG4 is even more important for developing nations as receiving proper education or vocational training, especially in science and technology, means a foundational step in improving other aspects of their citizens’ lives. However, the extant scientific literature about STEM education still lacks focus on developing countries, even more so in the rural area. Using a dataset of 4967 observations of junior high school students from a rural area in a transition economy, the article employs the Bayesian approach to identify the interaction between gender, socioeconomic status, and students’ STEM academic achievements. The results report gender has little association with STEM academic achievements; however, female students (αa_Sex[2] = 2.83) appear to have achieved better results than their male counterparts (αa_Sex[1] = 2.68). Families with better economic status, parents with a high level of education (βb(EduMot) = 0.07), or non-manual jobs (αa_SexPJ[4] = 3.25) are found to be correlated with better study results. On the contrary, students with zero (βb(OnlyChi) = -0.14) or more than two siblings (βb(NumberofChi) = -0.01) are correlated with lower study results compared to those with only one sibling. These results imply the importance of providing women with opportunities for better education. Policymakers should also consider maintaining family size so the parents can provide their resources to each child equally
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