Numerical Methods for Parameter Estimation and Optimal Control of the Red River Network

In this thesis efficient numerical methods for the simulation, the parameter estimation, and the optimal control of the Red River system are presented. The model of the Red River system is based on the Saint-Venant equation system, which consists of two nonlinear first-order hyperbolic Partial Differential Equations (PDE) in space and in time. In general a system of equations of this type can not be solved analytically. Therefore I choose a numerical approach, namely the Method Of Lines (MOL) combined with the Backward Differentiation Formulae (BDF) method implemented in the solver DAESOL, which is developed at IWR (University of Heidelberg), for the solution of the Saint-Venant equation for the simulation of the Red River system. In a river, there are geometrical and hydraulic parameters, e.g. friction coefficients, river bed slope, etc., which are very expensive or -- even worse -- impossible to measure. The Red River system is a large system, therefore the number of the unknown parameters is also large, thus manual parameter estimation, as often done by hydrologists, does not work effectively. To overcome this problem and to come up with accurate parameter values, we estimate these parameters by solving a corresponding least-squares problem. This high dimensional nonlinear constrained optimization problem is solved by applying a special reduced Gauss-Newton method implemented in the software packages for parameter estimation PARFIT and FIXFIT. Based on the code FIXFIT we have developed a numerical tool for solution of simulation and parameter estimation problems for river flows that are modeled by hyperbolic PDE. Using the validated model, we formulate an optimal control problem for preventing floods in the Red River lowland. This problem is solved by the direct multiple shooting method within the software package MUSCOD-II. We propose an online optimization approach with a Nonlinear Model Predictive Control (NMPC) technique to reduce the maximum flood level at Ha Noi by controlling the water discharge at the output of the reservoir Hoa Binh. The potential of our approach is demonstrated in real-life test cases corresponding to the flood season in the year 2000

Assessment and Simulation of Impacts of Climate Change on Erosion and Water Flow by Using the Soil and Water Assessment Tool and GIS: Case Study in Upper Cau River basin in Vietnam

The Upper Cau river basin which plays an important role in socio-economic developments the North of Vietnam is sensitive to changes of climate influencing flows, erosion, and water resources. The main objective of this study is to assess and simulate impacts of climate change on erosion and water flow in the basin. Using a GIS database and Soil and Water Assessment Tool (SWAT) model, the water flow and soil loss were assessed with data in period 1980-1999 called the based period, then simulated until 2100 considering the medium emission scenario (B2). The simulation result showed that the total annual runoff and soil loss tends to increase compared to the base period. For flow, the change rate of the simulation period is higher than the base period; the water flow rate will increase by 0.22% (2020-2039) and up to 1.37% (2080-2100). The total annual soil loss of the simulation period at Gia Bay station tends to increase steadily compared to the baseline, namely by 6.2% (2020-2039) and 25.5% (2080-2100). Overall, the result in this study shows that effects of climate changes on the basin are severe enough under the scenario B2 which is useful for authorities for basin management.ReferencesAli R., McFarlane D., Varma S., Dawes W., Emelyanova I., Hodgson G., Charles S., 2012. Potential climate change impacts on groundwater resources of south-western Australia. Journal of Hydrology, 475, 456-472. doi: http://dx.doi.org/10.1016/j.jhydrol.2012.04.043 Arnell N. W., 2004. Climate change and global water resources: SRES emissions and socio-economic scenarios. Global Environmental Change, 14(1), 31- 52. doi:10.1016/j.gloenvcha.2003.10.006 Arnold J. G., Fohrer N., 2005. SWAT2000: Current capabilities and research opportunities in applied watershed modeling. Hydrol. Proc., 19(3), 563-572. Arnold J.G., Kiniry J.R., Srinivasan R., Williams J.R., Haney E.B., Neitsch S.L., 2012. Soil and water assessment tool. Input/output Documentation: Texas Water Resources Institute. Beare S., Heaney A., 2002. Climate Change and water resources in the Murray Darling Basin, Australia, impacts and possible adaptation. Paper presented at the World Congress of Environmental and Resource Economists, Monterey, California, USA. Binh N.D., Tuan N.A., Huong H.L., 2010. SWAT application coupled with web technologies for soil erosion assessment in north western region of Vietnam. Paper presented at the International SWAT Conference Mayfield Hotel. Seoul, South Korea: Hanoi University of Algriculture. Chau T.L.M., Tuan N.Q., 2011. Application of SWAT for soil erosion management at river subbasins in Duong Hoa commune, Huong Thuy town, Thua Thien Hue province. Paper presented at the 3rd National GIS conference Danang University of Education, Danang, Vietnam. CLIMsystems. http://www.climsystems.com/simclim/. Department of Geography, L. U. SDSM Statistical Downscaling Model: http://copublic.lboro.ac.uk/cocwd/SDSM/software.html. FAO. http://www.fao.org/land-water/databases-and-software/cropwat/en/. Hanratty M.P., Stefan H.G., 1998. Simulating climate change effects in a Minnesota agricultural watershed. J. Environ. Qual., 27, 1524-1532. IPCC, 2000. Special Report on Emissions Scenarios. United States of America. IPCC, 2007. Fourth Assessment Report: Climate Change 2007 (AR4). Li Y., Chen B.M., Wang Z.G., Peng S.L., 2011. Effects of temperature change on water discharge, and sediment and nutrient loading in the lower Pearl River basin based on SWAT modeling. Hydrolog. Sci. J., 56, 68-83. Liem N.D., Hong N.T., Minh T.P., Loi N.K., 2011. Assessing water discharge in Be river basin, Vietnam using GIS and SWAT model. Paper presented at the National GIS application Vietnam. http://gisnetwork.vn/wpcontent/uploads/2012/04/GIS2011_BAI1.swf. McBean E., Motiee H., 2008. Assessment of impact of climate change on water resources: a long term analysis of the Great Lakes of North America. Hydrology and Earth System Sciences, 12, 239-255. MONRE, 2009. Climate Change, Sea level rise scenarios for Vietnam.  Vietnam. MONRE, 2012. Climate Change, Sea level rise scenarios for Vietnam.  Vietnam. MONRE, 2016. Climate Change, Sea level rise scenarios for Vietnam.  Vietnam. Nhu N.Y., 2011. Researching on the impacts of Climate Change on the extreme of the flow on Nhue-Day rivers basin, Hanoi. (Master), Hanoi University of Science, Hanoi National University, Vietnam. Ouyang W., Gao X., Hao Z., Liu H., Shi Y., Hao F., 2017. Farmland shift due to climate warming and impacts on temporal-spatial distributions of water resources in a middle-high latitude agricultural watershed. Journal of Hydrology, 547, 156-167.  http://dx.doi.org/10.1016/j.jhydrol.2017.01.050 Phan D.B., Wu C.C., Hsieh S.C., 2011. Impact of Climate Change and Deforestation on Stream Discharge and Sediment Yield in Phu Luong Watershed, Viet Nam Environmental Science and Engineering, 5, 1063-1072. Phan D.B., Wu C.C., Hsieh S.C., 2011. Impact of Climate Change on Stream Discharge and Sediment Yield in Northern Vietnam. Water Resources, 38(6), 827-836. doi: 10.1134/S0097807811060133. Rossi C.G., Srinivasan R., Jirayoot K., Duc T.L., Souvannabouth P., Binh N.D., Gassman P.W., 2009. Hydrologic evaluation of the lower Mekong river basin with the soil and water assessment tool model. International Agricultural Engineering, 18, 1-13. Son N.T., Tuan N.C., Hang V.T., Nhu N.Y., 2011. Impact of climate change on water resources to transform Nhue-Day rivers basin. Natural and Technological Science, 27, 218-226. Thang T.Q., 2010. Application of remote sensing images and GIS technique to assess soil erosion in Tam Nong Commune, Phu Tho province. Master. Hanoi University of Agriculture, Hanoi. Trong T.D., Viet N.Q., Huong D.T.V., 2012. Assessing the soil erosion possibility in Dakrong Commune, Quang Tri province using RMMF (Rrevised Morgan-Morgan-Finney) model. Scientific journal, Hue University,Vietnam, 74A(5), 173-184. Tu L.H., Liem N.D., Minh T.P., Loi N.K., 2011. Assessing soil erosion in Da Tam watershed, Lam Dong province using GIS technique Paper presented at the National GIS application  Danang, Vietnam. Penginapan Ciawi. (2020). Retrieved 21 May 2020, from http://www.penginapanciawi.my.id/ Vargas-Amelin E., Pindado P., 2014. The challenge of climate change in Spain: Water resources, agriculture and land. Journal of Hydrology, 518, Part B, 243-249. http://dx.doi.org/10.1016/j.jhydrol.2013.11.035 Winchell M., Srinivasan R., Di Luzio M., Arnold J., 2013. ArcSWAT Interface for SWAT 2012. User's Guide. Texas: Blackland Research and Extension Center; Grassland Soil and Water research laboratory

SURVEY ON VOCABULARY LEARNING STRATEGIES OF HIGH–QUALITY ENGLISH STUDIES PROGRAM STUDENTS, SCHOOL OF FOREIGN LANGUAGES, CAN THO UNIVERSITY, VIETNAM

This research study aimed to investigate the usage of vocabulary learning strategies among English Studies students at Can Tho University (CTU), specifically those under the high-quality program at the School of Foreign Languages (SFL). The primary objective of the study was to identify the most commonly used strategies for learning English vocabulary and to compare the similarities and differences in how these strategies were applied among students by academic year. A total of 200 survey responses from SFL, CTU got involved in the study, and 12 of whom joined a semi-structured interview. The data gathered were analyzed using both descriptive and inferential statistical techniques. The results of this study provided insights into effective vocabulary learning strategies and would facilitate the improvement of English language teaching and learning practices at the university level.  Article visualizations

Perceived Audit Quality, Earnings Management and Cost of Debt Capital: Evidence from the Energy Listed Firms on Vietnam's Stock Market

This study examines the impact of perceived audit quality and accrual-based earnings management on cost of debt capital of the energy listed firms on Vietnam's stock market. Our data set includes 29 energy companies on Vietnam stock markets (HNX and HOSE) in the period from 2010 to 2016. We used FEM and REM estimator to test our hypotheses. The results confirm that there is no significant statistical association between accrual-based earnings management and cost of debt. There is a negative association between audit quality, firm size, return on assets and cost of debt while firm leverage and the tangible asset has a positive association. Moreover, global financial crisis has no statistically significant influence on the cost of debt capital. The research results have implications for regulators and investors about the stability of the economy in emerging markets. Keywords: cost of debt, earnings management, audit quality, energy enterprises, Vietnam. JEL Classifications: M42; G32 DOI: https://doi.org/10.32479/ijeep.699

The Relationship between Public Debt, Budget Deficit, and Sustainable Economic Development in Developing Countries: The Role of Corruption Control

This study investigates the effects of public debt and budget deficits on the sustainable economic development of developing countries, taking into account the role of control of corruption. The two-step GMM method was applied for unbalanced panel data of 59 developing countries from 2004 to 2015. The study found that public debt and the budget deficit had negative effects on sustainable development, while the effect of control of corruption was positive. Moreover, using interaction terms between control of corruption and public debt and budget deficit, respectively, empirical results showed that controlling corruption limited these adverse effects. Thus, if the objective is to achieve sustainable economic development, developing countries should not see raising public debt or maintaining budget deficits as a strategy for economic development. The study contributes empirical evidence to the theory of debt overhang, crowded effects, and institutional theory in the context of developing countries. The implications are also discussed in this paper

THE IMPACT OF INNOVATION ON ECONOMIC GROWTH: THE SPILLOVER EFFECT OF FOREIGN DIRECT INVESTMENT

Purpose of the study: Innovation is seen as the key to improving quality and productivity, thereby promoting competition and economic growth. This study analyzes the impact of innovation on economic growth through various measures, such as research and development spending, the number of researchers, number of patents as well as trademark registrations. Research results are evidence to recommend policies for intellectual-based economic growth. Methodology: Literature review and empirical analysis conducted in the study. The empirical method is a two-step System Generalize Methods of Moments (GMM), aiming at reliable results. Accessing the World Bank Database, research data from 64 developed and developing countries are collected from 2006 to 2014. Main Findings: The empirical findings show that innovation plays a crucial contribution in promoting economic growth, similar to national openness and government spending on education. This study also finds a positive impact on foreign investment flows and their spillover role in enhancing the correlation between innovation and economic growth. Applications of this study: The findings of this study focus on the contributions of innovation, foreign direct investment inflows, and other macro factors that can be enforced to improve economic growth by policymakers. Novelty/Originality of this study: The study uses different measures of innovation, including inputs such as the number of researchers, research and development expenditure, and outputs as the number of patents and number of trademark registrations. Empirical findings are found consistently, thus confirming that innovation is very important for economic growth. The study also shows convincing evidence confirming the positive contribution of foreign direct investment as well as its spillover effect on innovation and economic growth

Evaluation Of Allelopathic Potential Of Cissus sicyoides Against the Growth Of Echinochloa Crus-Galli And Some Tested Plants

Many plant species in nature exert significant allelopathic potential as part of the defense mechanism system, many among their secondary metabolites (allelochemicals), including mineral constituents, which are responsible for the suppression of weeds and enhancing crop yield when directly incorporated into paddy fields. Cissus sicyoides is considered a high-potential allelopathic plant because of its invasion in nature and detected allelochemicals from the plant parts in some studies. The objective of this research was to exploit the allelopathic properties of C.sicyoides against paddy weeds and some indicator plants under laboratory bioassays and greenhouse conditions. The results demonstrated that C. sicyoides had significant inhibition on E. crus-galli, tested plants, and other paddy weeds. In the laboratory conditions, the extracts from C.sicyoides leaves inhibited the growth of Echinochloa crus-galli by 54.3%. The powders from C.sicyoides leaves inhibited the emergence of paddy weeds by approximately 100.0%. In the greenhouse conditions, the powders from C.sicyoides leaves by adding after 3 and 13 days inhibited the growth of E. crus-galli and the emergence of paddy weeds by 64.4%. Remarkably, negligible harmful effects on rice growth were observed. The findings of the study may provide useful information for the exploitation of this plant species to effectively control weeds in the rice fields for sustainable agriculture production

Data Structure Model on the Quality of Public Passenger Transport Services by Bus in Vietnam

The system of managing public passenger transport services (PPTS) by bus is a complex system, involving infrastructure, facilities, management and service communication activities between passengers and transport systems. In particular, quality information is the most important factor, providing necessary data for analysis, setting out measures to improve quality to meet the needs of passengers and meet the requirements of related parties. According to the peculiarity of the service, this study selects a database structure model to guide the process of computerizing the management of quality of PPTS by bus in urban areas in Vietnam. The results show that four database systems reflecting the quality information of the infrastructure, means of transport, transport operation and passenger service and each database system is structured by components that ensure proper implementation of QM process according to the continuous quality improvement cycle. The components of each database system are dispersed according to the scope of management to ensure the consistency for the quality management process and facilitate the collection, processing and distribution of information of related parties. Keywords: Quality, transport services, public passengers, Vietnam. DOI: 10.7176/JESD/10-10-13 Publication date:May 31st 201

Pisachini planthoppers of Vietnam: new records of Pisacha and a new Goniopsarites species from Central Vietnam (Hemiptera, Fulgoromorpha, Nogodinidae)

Two planthopper species of the family Nogodinidae are added to the fauna of Vietnam, both from two localities in Thua Thien-Hue Province: Bach Ma National Park and Phong Dien District. The first species belongs to Goniopsarites Meng, Wang & Wang, 2014, G. mientrunganus Constant & Pham, sp. nov., and the second belongs to Pisacha Distant, 1906, P. yinggensis Meng, Wang & Wang, 2014. Pisacha yinggensis was previously recorded from Hainan Island, China. These new records greatly extend the distribution of both genera, which were known from southern China, Hainan and North Vietnam, to the south, reaching the mid area of Central Vietnam. Sexual dimorphism is reported in P. yinggensis for the first time. Illustrations of habitus and male terminalia of the new species are given as well as distribution maps and photographs of live specimens and their habitat. The family Nogodinidae now comprises nine species in Vietnam, with three of them present in Bach Ma National Park