• Communications of the Korean Mathematical Society
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• v.37 no.4
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• pp.1181-1197
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• 2022

We give a complete classification of simply connected and solvable real Lie groups whose nontrivial coadjoint orbits are of codimension 1. This classification of the Lie groups is one to one corresponding to the classification of their Lie algebras. Such a Lie group belongs to a class, called the class of MD-groups. The Lie algebra of an MD-group is called an MD-algebra. Some interest properties of MD-algebras will be investigated as well.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.19-27
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• 2020

This research investigates the determinants of investment capital size in Vietnam's small and medium-sized firms. The study employs a sample of 458 small and medium-sized enterprises in the country. The study is based on data collects in the areas of Hanoi, Bac Can, Buon Ma Thuot and Pleiku Provinces at time series data of October 2019. This study also identifies the factors that affect the size of investment capital in medium and small-sized enterprises in Vietnam. Data are processed via STATA 14.0 and SPSS 20.0 software. The research results indicate that (1) business lines, (2) import and export business, (3) type of business registration, (4) business location, (5) operating time, and (6) the percentage of the organization's capital contribution are factors that impact on the size of the investment capital of the business. Business line and business location have negative impacts on investment capital size. The operating time, the percentage of the organization's capital contribution, import and export business, and the type of business registration have positive impacts on investment capital size. In addition, the findings of this study also suggest that the operation time has the highest impact on investment capital size of the small and medium-sized firms in Vietnam.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.641-649
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• 2020

The study examines the effect of environmental factors on the international harmonization process of accounting on small and medium enterprises in Vietnam. These factors include legal environment, business environment, and cultural environment. The data is collected by a survey of 100 accountants and 100 auditors on the factors that affects the international harmonization process of accounting. The T-Tests indicate differences between the answers of the accountants and auditors. First, for the accountants, legal environment has the biggest effect on the harmonization process of accounting; while on the auditors, business environment has the biggest influence. Second, while the accountants consider costs higher than benefits in the harmonization process of accounting, the auditors assume that benefits are superior to costs that businesses spend. Third, both the accountants and the auditors indicate that the harmonization process of accounting should not be applied for all small and medium enterprises. From the study results, the author has given a different evaluation method that Vietnam should implement for international harmonization with the required adjustments as per the suitability with the status of businesses in Vietnam. The process of harmonization in accounting practices should not be indiscriminately applied to all the small and medium enterprises either.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.193-200
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• 2021

This study investigates the impact of managerial ability and managerial incentives on firm performance. In particular, it studies how managerial ability factor can exert significant influence on the profitability and the risk of firms. By doing this, the study can provide several policy implications about how managerial ability can influence firm decisions and its corresponding business policies. Data of the study was collected from the Annual Enterprises Survey (AES), which is conducted by the General Statistics Office of Vietnam (GSO) during the 2009-2013 period. After removing firms with insufficient financial information, our final dataset includes over 50,000 firms in Vietnam. The main result of the study shows that there is a significant and positive relationship between managerial ability and firm leverage. This finding indicates that managerial ability significantly plays an important role in making financial decisions. In addition, our study provides empirical evidence about the causal relationship between managerial compensation and firm risk-taking behavior. Specifically, we find that firm risks are significantly associated with compensation schemes including lower delta and higher vega. In other words, our study implies that the sensitivity of CEO wealth to stock volatility can positively affect both delta and vega or managerial incentives schemes.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.649-657
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• 2021

This paper aims to study the impact of natural disasters on per capita income in Vietnam both the short and long-term, specifically impact loss of income caused by the extreme drought 2013 for agriculture, forestry and fishery in Phu Yen Province, Central Vietnam. The study valued economic damage by applying the synthetic control method (SCM), which is a statistical method to evaluate the effect of an intervention (e.g. natural disasters) in different case studies. It estimates what would have happened to the treatment group if it had not received the treatment by constructing a weighted combination of control units (e.g. control provinces). The results showed that the 2013 drought caused a decrease in income per capita, mainly in the agriculture, forestry, and fishery sector in Phu Yen. The reduced income was estimated to be VND 160,000 (1 USD = 23,500 VND (2021)) for one person per month, accounting for 11% of total income per capita and continued to affect the income 6 years later. Therefore, authorities need to invest in preventive solutions such as early and accurate warnings to help people to be more proactive in disaster prevention.

• Journal of Distribution Science
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• v.20 no.4
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• pp.77-83
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• 2022

Purpose: This study aims to find the impact of international trade cooperation and distribution on foreign direct investment (FDI). The study also tests the impact of lag variables of trade cooperation and distribution on FDI in the future. Research design, data, and methodology: Autoregressive Distributed Lag model is applied to analyze the impact of chosen variables such as total trade (TRADE), trade openness (OPEN), the exchange rate (EXR), inflation (INF), and gross domestic growth (GDP) on FDI. Quarterly data is collected from Vietnam General Statistic Office, Vietnam General Department of Customs, International Monetary Fund, and The World Bank from 2006 to 2020. Stata 14 software is used to analyze the regression and test variables. Results: The findings indicate that TRADE, OPEN, INF, GDP, and their lags affect both positively and negatively on FDI in different periods. While OPEN still expresses an unclear impact on FDI. Moreover, this study proves that the FDI of a nation is influenced by international cooperation. Conclusions: This study indicates the importance of international trade cooperation and distribution in not only attracting foreign investment sources but also developing the economy. Findings are necessary bases for governments or authorities in signing international trade agreements in the future.

• SUVANNABHUMI
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• v.2 no.2
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• pp.53-68
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• 2010

In this paper, we examine the traditional culture features of Vietnam, Cambodia, and Thailand and above this we try to find out the evidences that traditional culture features are shown up through the Constitutions of three countries. First, for Vietnam, unlike the other two countries, we could find out the traditional culture feature of strong resistance and struggle against the foreign powers like China throughout the history. Also, the loyalty for the community and country could be added as the traditional culture features as well. In contrast, for Cambodia and Thailand, we could see other aspects of traditional culture features, such as the promotion and protection of Buddhism, historically sustained Kingship and respect for the King, the opportunistic foreign policy for the foreign powers to national survive. Furthermore, we could find out the evidences that these traditional culture features are shown implicitly or explicitly in the Constitutions of the three countries in all. Although three countries have different historical backgrounds, experiences, cultures, and value systems, we could see that the Constitution of the three countries show that the traditional culture features are vigorously alive in it. Thus, we can say that this proves that the flow of traditional culture features are not easily changed or stopped by an era or ideology and still alive in the heart of the people.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.79-89
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• 2007

This paper provides a comprehensive overview of the present status of several environmental problems caused by emerging toxic substances such as persistent organic pollutants (POPs), endocrine disrupting chemicals (EDCs), and arsenic in various environmental media in Vietnam. Monitoring data reported during the 1990s demonstrated elevated contamination of DDTs in most of these compartments in Vietnam. Studies in frame of the Asia-Pacific Mussel Watch Program revealed that fish, mussels and resident birds from Vietnam contained higher concentrations of DDTs as compared to other countries in region, suggesting the role of Vietnamese environment as a significant emission source of DDT in the Southeast Asian region. The estimated dietary intakes of PCBs and DDTs for Vietnamese were relatively high among Asian developing countries, suggesting potential risk for humans posed by thesechemicals. Widespread contamination of some endocrine active compounds such as alkylphenols and phthalates was observed at various sites along the coasts of northern and middle Vietnam. The presence of significant source of bisphenol-A along Red River estuary was revealed with the concentrations comparable to those reported for developed nations. A case study on seasonal variation of alkylphenols and phthalates in surface water of river delta and estuary of north and middle Vietnam indicated the differences in distribution of these compounds between dry and rainy seasons. Higher concentrations of alkylphenols and phthalates were found in dry season in estuary; while the contrasting pattern was observed in the river delta, showing elevated residues in rainy season. This result suggests the different behavior of alkylphenols and phthalates in river delta and coastal environment. From ecotoxicological perspectives, concentrations of bis-phenol A and di(2-ethylhexyl)phthalates [DEHP] in surface water from some locations in Vietnam exceeded the guideline values for Ecotoxicological Effects and the Environmental Risk Limit, respectively, suggesting potential for toxic implications on aquatic wildlife. Widespread and elevated arsenic contamination was discovered inour recent surveys in groundwater in a large area of suburban areas of Hanoi city, the capital of Vietnam. The most recent investigation in 4 villages showed about more than 50 % of groundwater samples contained As concentrations exceeding 50 g/L (the WHO and Vietnamese standard). In particular, in Son Dong villages, 58 % of samples analyzed contained As concentrations higher than 200 g/L. Good correlations were found in As concentrations in water and hair and urine of peoples in corresponding families, suggesting the chronic exposure to As by people living in As-contaminated ground water areas. In Son Dong village, As levels in hair (mean: 1.7 mg/kg dry wt) and urine (g/g creatinine) exceeding the reference values recommended by WHO, suggesting potential for human risk posed by long term accumulation of As in human body. Future studies should be focused on the time trends of POPs and EDCs in biota in Vietnam in order to predict future trend of contamination and to reveal new clues for understanding possible toxic impacts on aquatic organisms. The issues of arsenic contamination in groundwater and their chronic toxic implications on human health should be systematically investigated in the future.

• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.85-90
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• 2023

The Ant Colony System (ACS) is a variant of Ant colony optimization algorithm which is well-known in Traveling Salesman Problem. This paper proposed a hybrid method based on genetic algorithm (GA) and ant colony system (ACS), called GACS, to solve traffic routing problem. In the GACS, we use genetic algorithm to optimize the ACS parameters that aims to attain the shortest trips and time through new functions to help the ants to update global and local pheromones. Our experiments are performed by the GACS framework which is developed from VANETsim with the ability of real map loading from open street map project, and updating traffic light in real-time. The obtained results show that our framework acquired higher performance than A-Star and classical ACS algorithms in terms of length of the best global tour and the time for trip.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.3
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• pp.444-454
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• 2016

This study was designed to examine the characteristics of sawdust and cocopeat bedding materials, including physicochemical properties (Exp. I) and on-farm trial (Exp. II). In Exp. I, the proportion of particle size was in the order of sawdust>cocopeat India>cocopeat Vietnam (p<0.05), and cocopeat contained higher proportion of small particles ($250{\mu}m$+below $250{\mu}m$) than sawdust, causing a dust production problem. Bulk density was cocopeat India>cocopeat Vietnam>sawdust (p<0.05), thus cocopeat treatments showed 4.4 times higher bedding cost than sawdust. The water absorption rates were 702.0% in cocopeat India, 678.3% in cocopeat Vietnam, and 444.0% in sawdust, showing cocopeat had approximately 1.5 times higher water absorption rate than sawdust. Moisture evaporation rates after 12 h of air blowing (2.00 m/s) were higher (p<0.05) in cocopeat Vietnam (80.4%) than sawdust (71.2%) and cocopeat India (72.8%). In vitro ammonia emissions were higher (p<0.05) in sawdust ($2.71mg/m^2/h$) than cocopeat India ($1.59mg/m^2/h$) and Vietnam ($1.22mg/m^2/h$), and total ammonia emissions were higher (p<0.05) in sawdust ($37.02mg/m^2$) than cocopeat India ($22.51mg/m^2$) and Vietnam ($13.60mg/m^2$). In Exp. II, an on-farm trial was conducted with 48 Hanwoo cattle in 16 pens using the same bedding materials as in Exp. I, with fan (blowing 2.00 m/s) and no fan treatments, and feed bunk side (FB) and water supply side (WS) within a pen (4.5 m, $width{\times}9.0m$, length). Beddings were replaced with fresh bedding materials when moisture concentrations were over 65%. No interactions among treatments were detected for moisture concentration and increment rates, and ammonia concentrations, but a significant effect was observed (p<0.01) for each of the treatments. Both concentrations and increment rate of moisture were higher (p<0.01) in the beddings without fan than with fan. Moisture concentrations and increment rate within a pen were also higher (p<0.01) in FB than WS. Thus, the whole no-fan-FB and sawdust-fan-FB were replaced with fresh bedding material between 4 to 5 experimental weeks. The ammonia concentrations and pH of beddings were not significantly different among treatments. Therefore, using cocopeat bedding with a blowing fan can extend twice the bedding utilization period, and WS within a pen showed twice the bedding-life compared to FB. Despite the outstanding characteristics of cocopeat compared with sawdust, using cocopeat as an alternative for sawdust bedding is not recommended for cattle management, considering it has 4.4 times higher bedding cost and a dust production problem.