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Novel Time Series Bagging Based Hybrid Models for Predicting Historical Water Levels in the Mekong Delta Region, Vietnam

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Computer Modeling in Engineering & Sciences 2022年第6期131卷 1431-1449页

作者： nguyen Thanh Hoan nguyen van Dung Ho Le Thu Hoa Thuy Quynh Nadhir Al-Ansari Tran van Phong Phan Trong Trinh Dam Duc nguyen Hiep van Le Hanh Bich Thi nguyen Mahdis Amiri Indra Prakash Binh Thai Pham Institute of Geography Vietnam Academy of Science and TechnologyHanoi10000Viet Nam Department of Civil Environmental and Natural Resources EngineeringLulea University of TechnologyLulea97187Sweden Institute of Geological Sciences Vietnam Academy of Science and Technology(VAST)Dong DaHanoi10000Viet Nam University of Transport Technology Thanh XuanHa Noi10000Viet Nam Department of Watershed&Arid Zone Management Gorgan University of Agricultural Sciences&Natural ResourcesGorgan***Iran DDG(R)Geological Survey of India Gandhinagar382010India

Water level predictions in the river,lake and delta play an important role in flood *** year Mekong River delta of Vietnam is experiencing flood due to heavy monsoon rains and high *** subsidence may also aggravate flooding problems in this ***,accurate predictions of water levels in this region are very important to forewarn the people and authorities for taking timely adequate remedial measures to prevent losses of life and *** are so many methods available to predict the water levels based on historical data but nowadays Machine Learning(ML)methods are considered the best tool for accurate *** this study,we have used surface water level data of 18 water level measurement stations of the Mekong River delta from 2000 to 2018 to build novel time-series Bagging based hybrid ML models namely:Bagging(RF),Bagging(SOM)and Bagging(M5P)to predict historical water levels in the study *** of the Bagging-based hybrid models were compared with Reduced Error Pruning Trees(REPT),which is a benchmark ML *** data of 19 years period was divided into 70:30 ratio for the *** data of the period 1/2000 to 5/2013(which is about 70%of total data)was used for the training and for the period 5/2013 to 12/2018(which is about 30%of total data)was used for testing(validating)the *** of the models was evaluated using standard statistical measures:Coefficient of Determination(R2),Root Mean Square Error(RMSE)and Mean Absolute Error(MAE).Results show that the performance of all the developed models is good(R2>0.9)for the prediction of water levels in the study ***,the Bagging-based hybrid models are slightly better than another model such as ***,these Bagging-based hybrid time series models can be used for predicting water levels at Mekong data.

关键词： Computational techniques bagging water level time series algorithms

Phototropin-and photosynthesis-dependent mitochondrial positioning in Arabidopsis thaliana mesophyll cells^FA

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Journal of Integrative Plant Biology 2020年第9期62卷 1352-1371页

作者： Md Sayeedul Islam Toan van nguyen Wataru Sakamoto Shingo Takagi Department of Biological Sciences Graduate School of ScienceOsaka UniversityMachikaneyama-cho 1-1ToyonakaOsaka 560-0043Japan Agricultural Genetics Institute National Key Laboratory for Plant Cell BiotechnologyPham Van Dong roadBac Tu Liem districtHa NoiVietnam Institute of Plant Science and Resources Okayama UniversityKurashikiOkayama 710-0046Japan

Mitochondria are frequently observed in the vicinity of chloroplasts in photosynthesizing cells, and this association is considered necessary for their metabolic in-teractions. We previously reported that, in leaf palisade cel s of Arabidopsis thaliana, mitochondria exhibit blue-light-dependent redistribution together with chloroplasts, which conduct accumulation and avoidance responses under the control of blue-light receptor phototropins. In this study, precise motility analyses by fluorescent micro-scopy revealed that the individual mitochondria in palisade cel s, labeled with green fluorescent protein, exhibit typical stop-and-go movement. When exposed to blue light, the velocity of moving mitochondria increased in 30 min, whereas after 4 h, the frequency of stoppage of mi-tochondrial movement markedly increased. Using different mutant plants, we concluded that the presence of both phototropin1 and phototropin2 is necessary for the early acceleration of mitochondrial movement. On the contrary, the late enhancement of stoppage of mitochondrial movement occurs only in the presence of phototropin2 and only when intact photosynthesis takes place. A plasma-membrane ghost assay suggested that the stopped mi-tochondria are firmly adhered to chloroplasts. These re-sults indicate that the physical interaction between mi-tochondria and chloroplasts is cooperatively mediated by phototropin2- and photosynthesis-dependent signals. The present study might add novel regulatory mechanism for light-dependent plant organel e interactions.

关键词： tropin Arabidopsis movement

Optimization, equilibrium, adsorption behavior and role of surface functional groups on graphene oxide-based nanocomposite towards diclofenac drug

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Journal of Environmental Sciences 2020年第7期32卷 137-150页

作者： Thuan van Tran Duyen Thi Cam nguyen Hanh TNLe Dai-Viet NVo Sonil Nanda Trinh Duy nguyen nguyen Tat Thanh Hi-Tech Institute Nguyen Tat Thanh UniversityHo Chi Minh City 755414Viet Nam Center of Excellence for Green Energy and Environmental Nanomaterials(CE@GrEEN) Nguyen Tat Thanh UniversityHo Chi Minh City 755414Viet Nam Institute of Hygiene and Public Health Ho Chi Minh City 700000Viet Nam Department of Chemical and Biochemical Engineering University of Western OntarioLondonOntarioCanada

Aquatic contamination of diclofenac(DCF),an emergent non-steroidal anti-inflammatory drug(NSAIDs),can result in adverse effects to many ecosystems through ***,introducing effective remediation techniques to sequester the pharmaceutical wastes is highly fundamental to prevent their accumulation in the ***,adsorption has been presented as a green and efficient ***,we report the characterization and application of the novel magnetic nanocomposite(GO@CoFe2O4)derived from cobalt-based ferrite(CoFe2O4)and graphene oxide(GO)for DCF *** the optimization procedure,the response surface methodology(RSM)was adopted to investigate the impacts of DCF concentration(1.6-18.4 mg/L),DCF dosage(0.08-0.92 g/L),and solution pH(2.6-9.4)to find the optimum conditions for DCF removal,at 10.5 mg/L,0.74 g/L,and pH 4,*** the adsorption experiments,the kinetic,isotherm,thermodynamic,and intraparticle diffusion models were systematically ***,we have elucidated the role of functional groups on the surface of GO@CoFe2O4 in enhancing the adsorption of DCF *** good removal efficiency(up to 86.1%),high maximum adsorption capacity(32.4 mg/g),GO@CoFe2O4 can be a potential candidate to eliminate DCF drug from water.

关键词： Diclofenac sodium Graphene oxide Magnetic nanocomposite Response surface methodology Pharmaceuticals adsorption

Morphological Change in the Northern Red River Delta,Vietnam

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Journal of Ocean University of China 2018年第6期17卷 1272-1280页

作者： BUI Vuong van FAN Daidu nguyen Dac Ve TRAN Dinh Lan TRAN Duc Thanh HOANG van Long nguyen Thi Hong Hanh Institute of Marine Environment and Resources Vietnam Academy of Science and TechnologyHaiphong 18000Vietnam State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China Hanoi University of Mining and Geology Hanoi 10000Vietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

Coastal erosion has become a worldwide concern, typically in the densely populated Asian mega-river deltas. Severe coastal erosion in the southern Red River Delta(RRD) has been intensively studied. Coastal morphological change in the northern RRD was examined in detail through DEM(Digital Elevation Model) analysis based on time series of bathymetrical maps(1965–2004) and Landsat images(1975–2015) in this study. The results show that the northern RRD is featured by rapid coastal accretion in the past few decades, although suspended sediment flux has dropped by roughly 60% after the completeness of Hoa Binh Dam(HBD) in 1988 and relative sea level rose at 1.9 mm yr^(-1). However, accretion at the outer part of subtidal shoals and platforms was observed to slow down quickly or even turned into erosion in the last two decades. The resuspended sediments from the erosion zone can be transported landward to replenish the inner coastal zone, keeping the latter accretion in the near future to compensate for the sediment discharge decrease from the river. However, this lag effect should be terminated soon if other adverse effects go worse, e.g., damming rivers, sea-level rising, strengthening storms, land reclamation and other poor-designed coastal engineering. Coastal planners and managers should pay full attention to these changes.

关键词： Morphological change DEM coastal erosion coastal engineering coastal management tide-dominated Red River Delta

Structural and luminescent properties of (Eu,Tb) PO_4·H_2O nanorods/nanowires prepared by microwave technique

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Journal of Rare Earths 2011年第12期29卷 1170-1173页

作者： nguyen Thanh Huong nguyen Duc van Dinh Manh Tien Do Khanh Tung nguyen Thanh Binh Tran Kim Anh Le Quoc Minh Institute of Materials Science Vietnam Academy of Science and Technology University of Engineering and Technology National University HanoiVietnam

Nanowires/nanorods of europium/terbium orthophosphate monohydrate with Eu^3＋ concentration of 6, 11, and 20 at.% were prepared by microwave synthesis method. The effects of Eu^3＋ doping concentration on structure, morphology and optical properties of nanomaterials were also investigated. The results showed that, for all studied Eu^3＋ doping concentrations, a single-crystalline phase of rhabdophane-type （Eu,Tb）PO4·H2O nanowires/nanorods was obtained by using microwave heating of an aqueous solution of terbium（Ⅲ） nitrate, europium（Ⅲ） nitrate and NH4H2PO4 with pH=2. The length and width of these nanowires/nanorods ranged from 150 to 300 nm and from 10 to 50 nm, respectively. The evidence of energy transfer from Tb^3＋ to Eu^3＋ due to the energy overlap between the donor Tb^3＋ and the acceptor Eu^3＋was observed obviously via a significant enhancement in the luminescent intensity of Eu^3＋. Keywords：

关键词： microwave technique nanowires/nanorods energy transfer fluorescence spectroscopy rare earths

Prediction of BRIC Stock Price Using ARIMA,SutteARIMA,and Holt-Winters

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Computers, Materials & Continua 2022年第1期70卷 523-534页

作者： Ansari Saleh Ahmar Pawan Kumar Singh nguyen van Thanh nguyen Viet Tinh Vo Minh Hieu Department of Statistics Faculty of Mathematics and Natural ScienccesUniversitas Negeri MakassarMakassar90223Indonesia School of Humanities and Social Sciences Thapar Institute of Engineering and TechnologyPatiala147004India Faculty of Commerce Van Lang UniversityHo Chi Minh City70000Vietnam

The novel coronavirus has played a disastrous role in many countries *** outbreak became a major epidemic,engulfing the entire world in lockdown and it is now speculated that its economic impact might be worse than economic deceleration and *** paper identifies two different models to capture the trend of closing stock prices in Brazil(BVSP),Russia(***),India(BSESN),and China(SSE),i.e.,(BRIC)*** predict the stock prices for three daily time periods,so appropriate preparations can be undertaken to solve these ***,we compared the ARIMA,SutteARIMA and Holt-Winters(H-W)methods to determine the most effective model for predicting *** stock closing price of BRIC country data was obtained from Yahoo *** data dates from 01 November 2019 to 11 December 2020,then divided into two categories-training data and test *** data covers 01 November 2019 to 02 December *** days(03December 2020 to 11December 2020)of datawas tested to determine the accuracy of the models using training data as a *** measure the accuracy of the models,we obtained the means absolute percentage error(MAPE)and mean square error(MSE).Prediction model Holt-Winters was found to be the most suitable for forecasting the Brazil stock price(BVSP)while MAPE(0.50)and MSE(579272.65)with Holt-Winters(smaller than ARIMA and SutteARIMA),model SutteARIMA was found most appropriate to predict the stock prices of Russia(***),India(BSESN),and China(SSE)when compared to ARIMA and *** andMSE with SutteARIMA:Russia(MAPE:0.7;MSE:940.20),India(MAPE:0.90;MSE:207271.16),and China(MAPE:0.72;MSE:786.28).Finally,Holt-Winters predicted the daily forecast values for the Brazil stock price(BVSP)(12 December to 14 December 2020 i.e.,115757.6,116150.9 and 116544.1),while SutteARIMA predicted the daily forecast values of Russia stock prices(***)(12 December to 14 December 2020 i.e.,3238.06,3241.54 and 3245.01),India stock price(BSESN)(

关键词： SutteARIMA Holt-Winters ARIMA stock price COVID-19

DENSITY ESTIMATES FOR SOLUTIONS OF STOCHASTIC FUNCTIONAL DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2019年第4期39卷 955-970页

作者： nguyen Tien DUNG Ta Cong SON Tran Manh CUONG nguyen van TAN Trinh Nhu QUYNH Department of Mathematics FPT University Hoa Lac High Tech Park Hanoi Vietnam Department of Mathematics VNU Hanoi University of Science 334 Nguyen Trai Thanh Xuan Hanoi Vietnam Department of Foundation Academy of Cryptography Techniques Hl Chien Thang Thanh Tri Hanoi Vietnam Military Information Technology Institute 17 Hoang Sam Cau Giay Hanoi Vietnam

In this article, we investigate the density of the solution to a class of stochastic functional differential equations by means of Malliavin calculus. Our aim is to provide upper and lower Gaussian estimates for the d... 详细信息

关键词： Stochastic functional differential equations density estimates Malliavin calculus

Optimization Model for Selecting Temporary Hospital Locations During COVID-19 Pandemic

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Computers, Materials & Continua 2022年第1期70卷 397-412页

作者： Chia-Nan Wang Chien-Chang Chou Hsien-Pin Hsu van Thanh nguyen Viet Tinh nguyen Department of Industrial Engineering and Management National Kaohsiung University of Science and TechnologyKaohsiung80778Taiwan Department of Shipping Technology National Kaohsiung University of Science and TechnologyKaohsiung80778Taiwan Department of Supply Chain Management National Kaohsiung University of Science and TechnologyKaohsiung80778Taiwan Faculty of Commerce Van Lang UniversityHo Chi Minh City70000Vietnam

The two main approaches that countries are using to ease the strain on healthcare infrastructure is building temporary hospitals that are specialized in treating COVID-19 patients and promoting preventive *** such,the selection of the optimal location for a temporary hospital and the calculation of the prioritization of preventive measures are two of the most critical decisions during the pandemic,especially in densely populated areas where the risk of transmission of the virus is *** the location selection process or the prioritization of measures is poor,healthcare workers and patients can be harmed,and unnecessary costs may come into *** this study,a decision support framework using a fuzzy analytic hierarchy process(FAHP)and a weighted aggregated sum product assessment model are proposed for selecting the location of a temporary hospital,and a FAHP model is proposed for calculating the prioritization of preventive measures against COVID-19.A case study is performed for Ho Chi Minh City using the proposed decision-making *** contribution of this work is to propose a multiple criteria decision-making model in a fuzzy environment for ranking potential locations for building temporary hospitals during the COVID-19 *** results of the study can be used to assist decisionmakers,such as government authorities and infectious disease experts,in dealing with the current pandemic as well as other diseases in the *** the entire world facing the global pandemic of COVID-19,many scientists have applied research achievements in practice to help decision-makers make accurate decisions to prevent the *** the number of cases increases exponentially,it is crucial that government authorities and infectious disease experts make optimal decisions while considering multiple quantitative and qualitative *** such,the proposed approach can also be applied to support complex decision-making processes in a fuzzy environment in di

关键词： COVID-19 WHO MCDM preventive measures fuzzy theory FAHP WASPAS

LiMn_2O_4/CNTs and LiNi_(0.5)Mn_(1.5)O_4/CNTs Nanocomposites as High-Performance Cathode Materials for Lithium-Ion Batteries

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Acta Metallurgica Sinica(English Letters) 2015年第1期28卷 122-128页

作者： Thang van Le Ha Tran nguyen Anh Tuan Luu Man van Tran Phung Loan My Le Faculty of Materials Technology Ho Chi Minh University of Technology 268 Ly Thuong Kiet Ward 14 District 10 Ho Chi Minh City Vietnam Department of Physical Chemistry University of Science VNUHCM 227 Nguyen Van Cu Street District 5 Ho Chi Minh CityVietnam

The demand of higher energy density and higher power capacity of lithium（Li）-ion secondary batteries has led to the search for electrode materials whose capacities and performance are better than those available today. Carbon nanotubes（CNTs）, with their unique properties such as 1D tubular structure, high electrical and thermal conductivities, and extremely large surface area, have been used as materials to prepare cathodes for Li-ion batteries. The structure and morphology of CNTs were analyzed by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and transmission electron microscopy（TEM）. The functional groups on the purified CNT surface such as –COOH, –OH were characterized by Fourier Transform infrared spectroscopy. The electrode materials were fabricated from LiMn2O4（LMO）, doped spinel LiNi0.5Mn1.5O4, and purified CNTs via solid-state reaction. The structure and morphology of the electrode were characterized using XRD, SEM, and TEM. Finally, the efficiency of the electrode materials using CNTs was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy.

关键词： Nanocomposites Carbon nanotubes(CNTs) Spinel materials Lithium-ion batteries(LIBs)