检索结果-南通市图书馆

Random vibration analysis of FGM plates subjected to moving load using a refined stochastic finite element method

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第4期34卷 42-56页

作者： ngoc-Tu Do Trung Thanh tran Faculty of Mechanical Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam

The article introduces a finite element procedure using the bilinear quadrilateral element or four-node rectangular element(namely Q4 element) based on a refined first-order shear deformation theory(rFSDT) and Monte Carlo simulation(MCS), so-called refined stochastic finite element method to investigate the random vibration of functionally graded material(FGM) plates subjected to the moving *** advantage of the proposed method is to use r-FSDT to improve the accuracy of classical FSDT, satisfy the stress-free condition at the plate boundaries, and combine with MCS to analyze the vibration of the FGM plate when the parameter inputs are random quantities following a normal distribution. The obtained results show that the distribution characteristics of the vibration response of the FGM plate depend on the standard deviation of the input parameters and the velocity of the moving ***, the numerical results in this study are expected to contribute to improving the understanding of FGM plates subjected to moving loads with uncertain input parameters.

关键词： FGM Moving load R-FSDT Q4 element Monte Carlo simulation Random vibration

EP Aquarii:A New Picture of the Circumstellar Envelope

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第3期24卷 83-105页

作者： Pham T.Nhung Do T.Hoai Pierre Darriulat Pham tuan-Anh Pham N.Diep Nguyen B.ngoc tran T.Thai Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa Noivietnam

New analyses of earlier ALMA observations of oxygen-rich AGB star EP Aquarii are presented,which complete a previously published analysis and offer a different interpretation of the morpho-kinematics of the circumstellar *** birth of the equatorial density enhancement(EDE)is shown to occur very close to the star where evidence for rotation has been *** to the star and where outflows have been observed:their interaction with the gas of the nascent EDE is seen to play an important role in the development of the wind and the evolution of its radial velocity from 8 to 10 km s^(-1) on the polar symmetry axis to~2 km s^(-1) at the *** implies complex morpho-kinematics:making reliable interpretations with reasonable confidence is *** particular,it questions an earlier interpretation implying the presence of a white dwarf companion orbiting the star at an angular distance of -0″4 from its *** proposes instead an interpretation in terms of a standard mass ejection associated with a shock wave leaving a void of emission in its *** Doppler velocity wings are seen to consist of two components,the upper velocity end of the global wind,reaching above±12 km s^(-1),and an effective line broadening,confined within 200 mas from the center of the star,reaching above±20 km s^(-1) and interpreted as caused by the pattern of shock waves resulting from the interaction between stellar pulsation and convective cell partition.

关键词： stars AGB and post-AGB-(stars) circumstellar matter-radio lines stars

Association between the Phenotypes and Genotypes of Antimicrobial Resistance in Haemophilus parasuis Isolates from Swine in Quang Binh and Thua Thien Hue Provinces, Vietnam

在线全文

学校读者我要写书评

暂无评论

Engineering 2020年第1期6卷 40-48页

作者： Chao Nguyen Van Lijun Zhang Tam Vu Thi Thanh Hung Pham Hoang Son tuan tran ngoc Qi Huang Rui Zhou State Key Laboratory of Agricultural Microbiology College of Veterinary MedicineHuazhong Agricultural UniversityWuhan 430070China Faculty of Animal Science and Veterinary Medicine University of Agricultural and ForestryHue UniversityHue 53000Vietnam Mientrung Institute for Scientific Research Vietnam Academy of Science and TechnologyHue 53000Vietnam Guangdong Provincial Key Laboratory of Marine Biology Shantou UniversityShantou 515063China Cooperative Innovation Center of Sustainable Pig Production Wuhan 430070China International Research Center for Animal Diseases The Ministry of Science and TechnologyWuhan 430070China

Haemophilus parasuis (H. parasuis) is one of the bacterial pathogens of great concern as it causes huge economic losses to the swine industry worldwide. One of the reasons why the control of H. parasuis has failed is the increase in antimicrobial resistance (AMR). The country of Vietnam has the second-largest pig production in Asia. However, there is still a lack of data about the AMR prevalence of H. parasuis in *** purpose of this study is to investigate the prevalence of AMR and analyze the association between AMR and AMR genes (ARGs). The H. parasuis strains used in this research were isolated from swine in the Quang Binh and Thua Thien Hue Provinces, Central Vietnam, as reported in our previous study. All of the strains were tested for AMR against 25 antibacterial agents using the broth microdilution method and for the presence of ARGs using the polymerase chain reaction (PCR) method. The tested strains were shown to have a high frequency of resistance to trimethoprim/sulfamethoxazole (94.6%), followed by resistance to colistin, chloramphenicol, gentamicin, penicillin, lincomycin, and amoxicillin. The most prevalent ARGs in these strains were blaTEM-1 (94.6%), int (76.8%), gyrA (58.9%), and rmtD (50.0%). Cefuroxime, chloramphenicol, and tobramycin resistances were strongly correlated with the presence of the ARGs blaROB-1 (odds ratio (OR) = 26.3, 95% confidence interval (CI) 2.7–255.7, p = 0.002), catl (OR = 25.1, 95% CI 2.4–258.9, p = 0.004), and strB (OR = 23.5, 95% CI 2.6–212.6, p = 0.001), *** study reveals for the first time the current situation of H. parasuis AMR in Central Vietnam, which is helpful for the clinical control of this disease, as well as for the development of policies and clinical practice guidelines to reduce AMR in swine production in Central Vietnam.

关键词： Haemophilus parasuis Antimicrobial resistance Antimicrobial resistance gene Vietnam

Exploring the Interplay between Job Stress,Work Performance,and Attitudes toward Professional Psychological Help among Employees

在线全文

学校读者我要写书评

暂无评论

International Journal of Mental Health Promotion 2024年第7期26卷 531-545页

作者： Cong Minh Le Son Van Huynh Ky Luu Quynh-Nhi ngoc Ho Van Thi Le Nguyen Vinh-Long tran-Chi Center for Mental Health Research and Support University of Social Sciences and HumanitiesVietnam National University Ho Chi Minh CityHo Chi Minh City700000Vietnam Faculty of Psychology Ho Chi Minh City University of EducationHo Chi Minh City700000Vietnam Faculty of Tourism College of BusinessUniversity of Economics Ho Chi Minh CityHo Chi Minh City700000Vietnam Scientific Management Department Dong A UniversityDa Nang500000Vietnam

Objective:This study explores the interplay between job stress,job-related factors,work performance,and attitudes toward seeking professional psychological help among Vietnamese ***:A total of 374 employees in Vietnam were surveyed using random sampling and an online questionnaire from November 07 to November 28,*** data and self-reported from three scales:The New Job Stress Scale(NJSS),Work Performance(WP),and Attitudes Toward Seeking Professional Psychological Help(ATSPPH_SF)were ***:Significant variations were found across several variables,including forms of work,operating hours,education levels,monthly income,numbers of daily working hours,and the presence of a psychological counseling department within the *** analysis has highlighted direct relationships between key latent *** who were more open to seeking professional help tended to report higher levels of job *** negative relationship was found between job stress and attitudes toward seeking professional ***,work effort was positively associated with work *** analyses revealed the influence of co-worker support on role expectation conflict and work effort,role expectation conflict and work-life balance,as well as interactions between role expectation conflict and attitudes needed toward seeking professional *** analyses showed that work effort mediated relationships between openness to seeking professional help,co-worker support,work-life balance,role expectation conflict,and work *** toward seeking professional help also mediated relationships between work-life balance,job stress,and work ***:The study highlights the complex dynamics surrounding job stress,job-related factors,work performance,and attitudes toward seeking professional psychological help among Vietnamese *** highlights the importance of addressing help-seeking barriers,promoting work engagement

关键词： Stress co-worker support work-life balance role expectation conﬂict professional psychological help-seeking

Building the ARIMA Model for Forecasting the Production of Vietnam’s Coffee Export

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Applied Mathematics and Physics 2024年第4期12卷 1237-1246页

作者： Duy Quang Phung Quoc Thang Trinh Quang Truong Do Ngan Giang Nguyen Van Ha Nguyen Gia Khiem Ngo Thi Minh ngoc tran Faculty of Technology and Data Science Foreign Trade University Hanoi Vietnam School of Economics and International Business Foreign Trade University Hanoi Vietnam

Coffee is a significant industry, accounting for 3% of Vietnam’s GDP, with annual export turnover consistently exceeding USD 3 billion. Despite global economic challenges affecting purchasing power at various times, Vietnam’s coffee exports in December 2023 continued to surge, reaching the highest level in the past 9 months at 190,000 tons, a 59.3% increase compared to November 2023, but still a slight 3.5% decrease from the same period last year. The export turnover reached USD 538 million, a 51% increase from November 2023 and a 26.4% increase from the same period last year. Therefore, forecasting the coffee export volume holds significant importance for coffee producers nationwide. This research employs the Box-Jenkins method to construct an ARIMA model for forecasting Vietnam’s coffee export volume based on annual data published by the General Statistics Office. Results indicate that among the models considered, the ARIMA(1, 1, 2) model is the most suitable. The study also provides short-term forecasts for Vietnam’s coffee export volume. However, the current model is limited to forecasting and is not yet optimized, as the assumed linearity in the model is a simplification.

关键词： ARIMA Forecasting Coffee Export Volume Data Science

The future of COVID-19 vaccination rates for children

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2022年第9期15卷 381-382页

作者： Giao Huynh Kimberly H.Nguyen Han Thi ngoc Nguyen tuan Diep tran Pham Le An Faculty of Public Health University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam Department of Public Health and Community Medicine Tufts University School of MedicineBostonMAUSA Infection Control Department University Medical Center Ho Chi Minh CityHo Chi Minh CityVietnam Faculty of Medicine University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam Family Medicine Training Center University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam

The COVID-19 pandemic has been ongoing for over two years since the first case was reported in the end of January *** has successfully controlled the pandemic through its vaccination campaign,targeted messages and applications of various public health interventions including social distancing,quarantining,masking,and hand washing,which have made some significant achievements in reducing hospitalizations and deaths[1].

关键词： vaccination targeted COV

An Efficient Differential Evolution for Truss Sizing Optimization Using AdaBoost Classifier

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2023年第1期134卷 429-458页

作者： tran-Hieu Nguyen Anh-tuan Vu Hanoi University of Civil Engineering Hanoi100000Vietnam

Design constraints verification is the most computationally expensive task in evolutionary structural optimization due to a large number of structural analyses thatmust be *** a surrogatemodel to approximate the behavior of structures instead of the exact structural analyses is a possible solution to tackle this ***,most existing surrogate models have been designed based on regression *** paper proposes a novel method,called CaDE,which adopts a machine learning classification technique for enhancing the performance of the Differential Evolution(DE)*** proposed method is separated into two *** the first optimization stage,the original DE is implemented as usual,but all individuals produced in this phase are stored as inputs of the training *** on design constraints verification,these individuals are labeled as“safe”or“unsafe”and their labels are saved as outputs of the training *** collecting enough data,an AdaBoost model is trained to evaluate the safety state of *** model is then used in the second stage to preliminarily assess new individuals,and unpromising ones are rejected without checking design *** method reduces unnecessary structural analyses,thereby shortens the optimization *** benchmark truss sizing optimization problems are solved using the proposed method to demonstrate its *** obtained results show that the CaDE finds good optimal designs with less structural analyses in comparison with the original DE and four other DE *** reduction rate of five examples ranges from 18 to over 50%.Moreover,the proposed method is applied to a real-size transmission tower design problem to exhibit its applicability in practice.

关键词： Structural optimization machine learning surrogate model differential evolution AdaBoost classifier

Object Detection in Remote Sensing Images Using Picture Fuzzy Clustering and MapReduce

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2022年第12期43卷 1241-1253页

作者： tran Manh tuan tran Thi Ngan Nguyen Tu Trung Faculty of Computer Science and Engineering Thuyloi University175 Tay SonDong DaHanoi010000Vietnam

In image processing, one of the most important steps is image segmentation. The objects in remote sensing images often have to be detected in order toperform next steps in image processing. Remote sensing images usually havelarge size and various spatial resolutions. Thus, detecting objects in remote sensing images is very complicated. In this paper, we develop a model to detectobjects in remote sensing images based on the combination of picture fuzzy clustering and MapReduce method (denoted as MPFC). Firstly, picture fuzzy clustering is applied to segment the input images. Then, MapReduce is used to reducethe runtime with the guarantee of quality. To convert data for MapReduce processing, two new procedures are introduced, including Map_PFC and Reduce_*** formal representation and details of two these procedures are presented in thispaper. The experiments on satellite image and remote sensing image datasets aregiven to evaluate proposed model. Validity indices and time consuming are usedto compare proposed model to picture fuzzy clustering model. The values ofvalidity indices show that picture fuzzy clustering integrated to MapReduce getsbetter quality of segmentation than using picture fuzzy clustering only. Moreover,on two selected image datasets, the run time of MPFC model is much less thanthat of picture fuzzy clustering.

关键词： Remote sensing images picture fuzzy clustering image segmentation object detection MapReduce

New Collective Signatures Based on the Elliptic Curve Discrete Logarithm Problem

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第10期73卷 595-610页

作者： tuan Nguyen Kim Duy Ho ngoc Nikolay A.Moldovyan School of Computer Science Duy Tan UniversityDa NangVietnam Department of Information Technology Ha NoiVietnam ITMO University St.PetersburgRussia

There have been many digital signature schemes were developed based on the discrete logarithm problem on a finite *** this study,we use the elliptic curve discrete logarithm problem to build new collective signature *** cryptosystem on elliptic curve allows to generate digital signatures with the same level of security as other cryptosystems but with smaller *** extend practical applicability and enhance the security level of the group signature protocols,we propose two new types of collective digital signature schemes based on the discrete logarithm problem on the elliptic curve:i)the collective digital signature scheme shared by several signing groups and ii)the collective digital signature scheme shared by several signing groups and several individual *** two new types of collective signatures have combined the advantages of group digital signatures and collective digital *** signatures have a fixed size and do not depend on the number of members participating in the creation of the final collective *** of the advantages of the proposed collective signature protocols is that they can be deployed on top of the available public key infrastructures.

关键词： Elliptic curve signing group individual signer collective signature group signature