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Stock-Price Forecasting Based on XGBoost and LSTM

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Computer Systems Science & Engineering 2022年第1期40卷 237-246页

作者： Pham hoang Vuong Trinh Tan Dat Tieu khoi Mai Pham hoang Uyen Pham The Bao Information Science Faculty Sai Gon UniversityHo Chi Minh City700000Vietnam University of Economics and Law Ho Chi Minh City700000Vietnam

Using time-series data analysis for stock-price forecasting(SPF)is complex and challenging because many factors can influence stock prices(e.g.,inflation,seasonality,economic policy,societal behaviors).Such factors can be analyzed over time for *** learning and deep learning have been shown to obtain better forecasts of stock prices than traditional *** study,therefore,proposed a method to enhance the performance of an SPF system based on advanced machine learning and deep learning ***,we applied extreme gradient boosting as a feature-selection technique to extract important features from high-dimensional time-series data and remove redundant ***,we fed selected features into a deep long short-term memory(LSTM)network to forecast stock *** deep LSTM network was used to reflect the temporal nature of the input time series and fully exploit future con-textual *** complex structure enables this network to capture more stochasticity within the stock *** method does not change when applied to stock data or Forex *** results based on a Forex dataset covering 2008–2018 showed that our approach outperformed the baseline autoregressive integrated moving average approach with regard to mean absolute error,mean squared error,and root-mean-square error.

关键词： stock-price forecasting ARIMA XGBoost LSTM deep learning

Thornthwaite moisture index and depth of suction change under current and future climate‒An Australian study

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1761-1775页

作者： Md Rajibul Karim Bikash Devkota Md Mizanur Rahman hoang Bao khoi Nguyen UniSA STEM University of South AustraliaMawson Lakes CampusMawson LakesSouth Australia5095Australia

Climate change is one of the major global challenges and it can have a significant influence on the behaviour and resilience of geotechnical *** changes in moisture content in soil lead to effective stress changes and can be accompanied by significant volume changes in reactive/expansive *** volume change leads to ground movement and can exert additional stresses on structures founded on or within a shallow depth of such *** change is likely to amplify the ground movement potential and the associated problems are likely to *** effect of atmospheric boundary interaction on soil behaviour has often been correlated to Thornthwaite moisture index(TMI).In this study,the long-term weather data and anticipated future projections for various emission scenarios were used to generate a series of TMI maps for *** changes in TMI were then correlated to the depth of suction change(H s),an important input in ground movement *** all climate scenarios considered,reductions in TMI and increases in H s values were observed.A hypothetical design scenario of a footing on expansive soil under current and future climate is *** is observed that a design that might be considered adequate under the current climate scenario,may fail under future scenarios and accommodations should be made in the design for such events.

关键词： Climate change Future prediction Thornthwaite moisture index(TMI) Characteristic surface movement Infrastructure resilience

Evaluation of five gridded rainfall datasets in simulating streamflow in the upper Dong Nai river basin,Vietnam

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International Journal of Digital Earth 2019年第3期12卷 311-327页

作者： Pham Thi Thao Nhi Dao Nguyen khoi Nguyen Xuan Hoan Institute of Research and Development Duy Tan UniversityDa NangVietnam Institute for Computational Science and Technology Tan Hiep Chanh WardDistrict 12Ho Chi Minh CityVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh City227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh CityVietnam Ho Chi Minh City University of Food Industry 140 Le Trong Tan StreetTan Phu DistrictHo Chi Minh CityVietnam

Rainfall data with an appropriate spatial resolution is a key input to hydrological ***,networks of rain gauges are often sparsely and unevenly distributed in large catchments,especially in developing ***-resolution rainfall datasets,such as the Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources(APHRODITE),the Climate Forecast System Reanalysis(CFSR),the Climatic Research Unit Time Series(CRUTS),the Global Precipitation Climatology Centre(GPCC)and the Tropical Rainfall Measuring Mission(TRMM),have become available to overcome such *** objective of this study was to evaluate the impacts of four land-based rainfall products(APHRODITE,CFSR,CRU-TS,and GPCC)and a satellite-based rainfall product(TRMM)on streamflow of the upper catchment of Tri An reservoir in Vietnam using the Hydrological Modeling System(HEC-HMS).In addition,the available rain gauges data were used for comparison *** indicates that the TRMM and GPCC data show their best match to rain gauges data in simulating the streamflow in the period 1999–***,the results indicate that the TRMM and GPCC data could be alternative solutions.

关键词： APHRODITE CFSR CRU-TS GPCC TRMM rainfall streamflow HEC-HMS model

Assessment of Livelihood Vulnerability to Drought: A Case Study in Dak Nong Province, Vietnam

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International Journal of Disaster Risk Science 2019年第4期10卷 604-615页

作者： Nguyen Thi Thanh Thao Dao Nguyen khoi Tran Thanh Xuan Bernard Tychon Universite de Liege 6700 ArlonBelgium Institute for Environmental Science Engineeringand ManagementIndustrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Institute of Research and Development Duy Tan UniversityDa NangVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh CityHo Chi Minh CityVietnam NTT Institute of Hi-Technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

In recent years,droughts have strongly affected the Central Highlands of Vietnam and have resulted in crop damage,yield decline,and serious water *** study investigated the livelihood vulnerability of five communities of farmers who are exposed to droughts in one of the more vulnerable regions of Vietnam—Dak Nong Province.A survey of 250 households was conducted in the five communities to collect data on the region’s sociodemographic profile,livelihood systems,social networks,health status,food and water security,drought conditions,and climate *** were aggregated using a livelihood vulnerability index and the IPCC vulnerability *** survey results indicate that Quang Phu community is the most vulnerable of the study’s communities,followed by Nam N’dir,Dak Nang,Duc Xuyen,and Dak D’ro in descending order of *** availability and livelihood strategies are the most important variables in determining the vulnerability of the five surveyed *** order to reduce vulnerability to droughts,water management practices and livelihood diversification in farming and nonfarming activities are recommended for the study area.

关键词： Agricultural drought Livelihood vulnerability Vietnam Vulnerability indicators

Spatiotemporal Trend Analysis of Precipitation Extremes in Ho Chi Minh City, Vietnam During 1980–2017

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International Journal of Disaster Risk Science 2021年第1期12卷 131-146页

作者： Nguyen Trong Quan Dao Nguyen khoi Nguyen Xuan Hoan Nguyen Ky Phung Thanh Duc Dang Faculty of Environmental and Food Engineering Nguyen Tat Thanh UniversityHo Chi Minh City 700000Vietnam Faculty of Environment University of ScienceHo Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City 700000Vietnam Ho Chi Minh City University of Food Industry Ho Chi Minh City 700000Vietnam Institute for Computational Science and Technology Ho Chi Minh City 700000Vietnam Engineering Systems and Design Pillar Singapore University of Technology and DesignTampines 487372Singapore

In this study,the spatiotemporal variability of trends in extreme precipitation events in Ho Chi Minh City during the period 1980–2017 was analyzed based on several core extreme precipitation indices(Rx1 day,Rx5 day,CDD,CWD,R20 mm,R25 mm,R95 p,and SDII).The nonparametric Mann–Kendall and Sen’s slope methods were used to compute the statistical strength,stability,and magnitude of trends in annual rainfall,as well as the extreme precipitation *** found that 64%of the stations had statistically significant upward trends in yearly rainfall,with high magnitudes frequently observed in the northern and southern regions of the *** the extreme precipitation indices,only SDII and R25 mm showed dominantly significant ***,there were increasing trends in the frequency and duration at the southern and central regions of the city during the study ***,El Ni?o-Southern Oscillation and Pacific Decadal Oscillation positively correlated with the duration and negatively correlated with the intensity and frequency of extreme ***,water management plans should be adjusted appropriately to reduce the severe impacts of precipitation extremes on communities and ecosystems.

关键词： Spatiotemporal trend Extreme precipitation Extreme precipitation indices Ho Chi Minh City

Electrical Tracking,Erosion and Fire Retardancy Performance of Silicone Rubber Insulation Containing Aluminum Trihydrate,Graphene and Glass Fiber Additives

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CSEE Journal of Power and Energy Systems 2023年第5期9卷 1918-1925页

作者： M.Tariq Nazir Arslan Khalid B.Toan Phung Arup K.Das Peter Cheetham Ashish Paramane Shakeel Akram khoi Loon Wong School of Engineering RMIT UniversityMelbourneVIC 3000Australia. the Center for Advanced Power Systems(CAPS) Florida State UniversityFL 32310USA the Flame Security International Pty Limited Australia the School of Electrical Engineering and Telecommunications University of New South Wales SydneyNSW 2052Australia Department of Electrical Engineering National Institute of TechnologySilcharAssam 788010India the College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjingJiangsu 211816China

Silicone rubber composite is a priority electrical insulating material used in high-voltage outdoor insulation *** electrical tracking/erosion and poor flame resistance performance of silicone rubber once ignited,substantially reduce its working *** paper attempts to investigate tracking/erosion performance of room temperature vulcanized(RTV)silicone rubber along with flame retardant parameters using aluminum trihydrate(ATH),graphene nanosheets(GN)and milled glass fiber(GF)*** inclined plane test(IPT)was performed in line with criteria defined in IEC 60587 using step-up tracking voltage method while flame retardancy is evaluated according to ASTM E 1354.0 using a cone *** suggest 30% of ATH assists in improving physical tracking/erosion resistance of pristine silicone elastomer rubber by impeding development of leakage current and a great reduction in maximum average temperatures on the surface of *** improvement in performance of RTV2 is achieved through introduction of 1%of GN and 5% of GF as seen in ***,30% of ATH reduces heat release rate and smoke production rate,and this trend is improved with the introduction of GN/***4 has pop up as the most promising silicone rubber composite with excellent electrical tracking,erosion,and flame resistance performance relative to its counterparts in this study.

关键词： Dry band arcing electrical tracking heat release rate leakage current silicone rubber smoke production rate

EchoNavigator virtual marker and Agilis NxT steerable introducer facilitate transseptal transcatheter closure of mitral paravalvular leak

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World Journal of Clinical Cases 2022年第13期10卷 4236-4241页

作者： Jung-Cheng Hsu Chong-Sun khoi Shan-Hui Huang Yi-Yao Chang Shu-Lu Chen Yen-Wen Wu Division of Cardiology Department of MedicineFar Eastern Memorial HospitalNew Taipei City 220216Taiwan General Education Center Lunghwa University of Science and TechnologyTaoyuan City 333026Taiwan Department of Anesthesiology Far Eastern Memorial HospitalNew Taipei City 220216Taiwan

BACKGROUND Paravalvular leak(PVL),also known as paravalvular prosthetic regurgitation,is not a rare complication after surgical valve replacement,and it may cause varying degrees of heart *** transcatheter closure of PVL is technically demanding and *** SUMMARY A 68-year-old man presented with degenerative mitral regurgitation with heart failure,New York Heart Association functional class *** received bioprosthetic mitral valve replacement in December *** was noted at the location of the aorto-mitral curtain in transesophageal echocardiography without signs of endocarditis or dehiscence of the bioprosthetic *** transcatheter closure of the mitral PVL was performed efficiently using the EchoNavigator virtual marker and Agilis NxT steerable *** This case highlights that the EchoNavigator virtual marker and Agilis NxT steerable introducer can facilitate transseptal transcatheter closure of mitral PVL by reducing the procedure time and contrast media.

关键词： Paravalvular leak Paravalvular prosthetic regurgitation EchoNavigator Steerable introducer Case report

Leveraging Quantum Computing for the Ising Model to Simulate Two Real Systems: Magnetic Materials and Biological Neural Networks (BNNs)

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Journal of Quantum Information Science 2023年第3期13卷 138-155页

作者： David L. Cao khoi Dinh Thomas Jefferson High School for Science and Technology Alexandria VA USA

Quantum computing is a field with increasing relevance as quantum hardware improves and more applications of quantum computing are discovered. In this paper, we demonstrate the feasibility of modeling Ising Model Hamiltonians on the IBM quantum computer. We developed quantum circuits to simulate these systems more efficiently for both closed and open boundary Ising models, with and without perturbations. We tested these various geometries of systems in both 1-D and 2-D space to mimic two real systems: magnetic materials and biological neural networks (BNNs). Our quantum model is more efficient than classical computers, which can struggle to simulate large, complex systems of particles.

关键词： Ising Model Magnetic Material Biological Neural Network Quantum Computting International Business Machines (IBM)

Natural and Anthropic Sources of Arsenic in the Groundwater and Soils of the Mekong Delta

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Open Journal of Soil Science 2022年第11期12卷 541-570页

作者： Kenneth R. Olson khoi Minh Chau College of Agricultural Consumer and Environmental Sciences University of Illinois Urbana USA College of Agriculture Can Tho University Can Tho Vietnam

Human exposure to arsenic (As) is primarily through drinking water and food ingestion. Arsenic is naturally present in the environment and has been known as “the king of poisons” since the Middle Ages. It is mutagenic, teratogenic, and carcinogenic and approximately 70% comes from ingested food and 29% from water. Once ingested, arsenic can bio-accumulate in the human body or be excreted. Arsenic in groundwater is a main source of As in humans and the two arsenicals most abundant in water are arsenite (+3 oxidation state) and arsenate (+5 oxidation state). In order of toxicity from the most toxic to least toxic are arsines, arsenites, arsenoxides, arsenates, pentavalent arsenicals, Arsenic compounds, and metallic arsenic. Arsenic accumulates in the body when ingested in small doses. It often takes decades before physical symptoms of As poisoning show. While As is element normally found in the human body, it is highly toxic in excess amounts. The lethal dose for rates is 48 μg/L which translates to 125 mg for a middle-aged male. The maximum safe limit for As ingestion for an average Vietnamese middle-aged male is 220 μg per day. This lethal dosage puts As in a highly toxic category in food and toxicology. Most of the As in the Mekong Delta groundwater is from natural alluvial sediment sources. Other anthropic sources include the burial of millions of Vietnamese with elevated As levels since 1962, industrial sources, smelting by-products, water treatment plants, sewage and wastewater treatment discharges into waterways have added to the Mekong Delta As levels in the soil and groundwater. However, Agent Blue, the As-based herbicide, used during the Vietnam War, did contribute a significant amount (over 1,132,400 kg of manufactured (anthropic) As) to Southern Vietnam landscape. The As spikes and levels in the Mekong Delta soils and groundwater need restoration. The uptake of trace amounts of As in rice is indeed a critical food security and human health issue and requir

关键词： Arsenic Mekong Delta Anthropic Arsenic Agent Blue Khai hoang Cacodylic Acid Water Treatment Plants