Influence function approximation to estimation in linear models with generalized t- distribution noise

Ph.DDOCTOR OF PHILOSOPH

Creating Fatigue Curve for Steel Machine Elements Using Fatigue Test Method with Gradually Increasing Stress Amplitude

In order to create a fatigue curve, the traditional fatigue test method is applied to specimens using a cyclic stress with constant amplitude. However, this method has disadvantages such as the experimental results could not be used because of specimens broken before reaching the expected stress amplitude, or the tests may be stopped before specimen broken because of limitation of time. To overcome this hurdle of the traditional method, a new experimental method using cyclic stress with gradually increasing amplitude was proposed to build the fatigue curve for steel machine elements

Distance-Based Formation Tracking with Unknown Bounded Reference Velocities

This paper studies a leader-follower formation tracking problem where the leaders are moving at the same unknown bounded velocity. A distance-based control law is proposed for follower agents to maintain the desired distances in the formation and move at the leaders' velocity. The control law consists of a component to handle the uncertainty of the leaders' velocity and a component to achieve the desired distances in finite time. Numerical simulations are also provided to support the theoretical results.Comment: accepted to ICCAS 202

REGIONAL LINKAGE IN TOURISM: THE CASE OF VIETNAM

Abstract. This research is conducted for investigating the current situations of regional linkage in tourism development in the areas of Midlands and Northern Mountains in Vietnam. Data were collected from a survey of 755 people, including officials from State management bodies in charge of tourism, officials and staffs at tourism resorts, tourism firms, tourism scientists and tourists. In addition, we conducted focus group and interviewed tourism agency officials and tourism firms in the Midland and Mountainous provinces of Vietnam. The results show that tourism development in Vietnam in general and the Northwest region in particular is extremely fragmented, not yet forming a regional linkage; regional and national tourism development projects are just formalistic. Some causes are the limited regional integration policy, lack of appropriate regional governance mechanisms and inactive participation of the private sector in regional integration. Based on the findings, we propose a tourism sector linkage model; besides, policyimplications are given for fulfilling the linkage policies in Vietnam in particular, and more broadly for emerging countries in general.Keywords: Midlands and Northern Mountains, tourism linkage, Vietnam

Datasets of land use change and flood dynamics in the vietnamese mekong delta

This paper compiles the data associated with a research article published in STOTEN [1]. The data set represents figures, tables, and images illustrating the temporal and spatial distribution of land use and flood dynamics from 2000 to 2020 in the Vietnamese Mekong Delta (VMD). The MODIS imageries were freely accessed online via the NASA website [2] and processed to land use and flood maps based on the algorithms by Sakamoto et al. [3,4]. The MODIS products show a high validation with statistical data and radar satellites [1]. The datasets of flood map and land use, therefore, are available to scientists, engineers, and policy-makers in agricultural management associated with flood management in the VMD. They could be used for policy settings, household livelihood assessment as well as other economic analyses for the VMD region due to the change of land use and flooding dynamics

Academic Anxiety of Vietnamese Secondary School Students as a Reason for Applying Online Learning

Academic anxiety is one of the major problems in student psychology across the world. It applies equally to students of all ages, from elementary school to college and university students. Research shows that learning online is an effective way to defuse feelings of academic anxiety. Elimination of anxiety is clearly visible regardless of age, gender, or prior online learning experience. The study aims to identify academic anxiety as one of the most important reasons for moving to online learning or blended learning in secondary school. The study investigated academic anxiety among secondary school students in Vietnam. After surveying 677 students in classroom learning, the results showed that 13.7% of secondary students suffered from frequent anxiety, and 3.0% of them suffered from very frequent anxiety. Lower anxiety was observed among students actively participated in-class activities, and students with excellent academic performance. These factors can be optimally enhanced through blended and online learning. There were no differences in academic anxiety among male and female students, urban and rural students. There was a moderate correlation between a student's anxiety level and pressure of the school, parental expectations, students' motivation for high performance, and especially, among students who have the melancholic temperament. And the influence of these negative factors can also be optimally reduced with the help of online learning. Regression model could provide useful suggestions for parents, teachers and students in reducing academic anxiety for students, including the use of full or blended online learning

A Research on the Quality of Public Transportation Services by Bus in Vietnam

This study was conducted to assess the status of the quality of public passenger transport services by bus in Hanoi. Data were collected from regular passengers using buses as a means of transportation in the city, including passengers standing at stations, waiting shelters and on vehicles to make trips and students of some universities who use buses as a means of transportation. We employ descriptive statistics and hierarchical analysis to learn about the topic of research. The results indicate that the quality of public transport services by buses in Hanoi, which was judged by passengers quite well. In particular, the safety level, convenience, security and hygiene is up to 70%, which was higher than the highest quality level. Quality of fast level and reliability are low. Keywords: quality of services, public passenger transport, buses, Vietnam. DOI: 10.7176/RJFA/10-13-04 Publication date:July 31st 201

FACTORS INFLUENCING THE INTENTION TO USE MOBILE MONEY: A STUDY IN BUSINESSES IN HANOI, VIETNAM

Abstract The government's and people's expectations for the successful implementation of this activity are significant, but the scientific basis for its implementation remains limited. This study, the first of its kind in Vietnam since the aforementioned decision, aims to clarify the factors influencing consumer usage of Mobile Money, focusing on businesses in Hanoi, Vietnam. Mobile Money, a form of mobile wallet not linked to bank accounts, represents a new transaction method in Vietnam, catering to consumers' reduced use of cash. This research examines the factors affecting the intention to use Mobile Money among employees of businesses in Hanoi. To achieve this goal, the author relies on the Theory of Reasoned Action (TRA), the Theory of Planned Behavior (TPB), the Technology Acceptance Model (TAM), and risk perception variables to design the research model. With a sample of 479 employees who intend to use Mobile Money, hypotheses are tested using a multivariate regression model through quantitative analysis with IBM SPSS Statistics 20.0. The research results identify five factors that positively influence the intention to use Mobile Money: Perceived Ease of Use, Trust, Security and Privacy, Social Influence, and COVID-19 Risk Perception. The factor of Perceived Usefulness does not have a significant impact in this case. Particularly, heightened risk perception regarding COVID-19 or social instability leads to an increased intention to use Mobile Money. This study provides guidance to Mobile Money service providers on how to enhance users' intention to use their services. Additionally, it underscores how factors related to diseases or societal instability can alter or even disrupt initial intention or behavior models

Evaluating the impacts of rice-based protection dykes on floodwater dynamics in the vietnamese mekong delta using geographical impact factor (Gif)

This study aims at evaluating the geographical influences of rice-based protection dykes on floodwater regimes along the main rivers, namely the Mekong and the Bassac, in the Vietnamese Mekong Delta (VMD). Specifically, numerous low dykes and high dykes have been constructed particularly in the upper delta’s floodplains to protect the double and triple rice cropping against the annual flooding. For the whole deltaic domain, a 1D-quasi-2D hydrodynamic model setup was used to simulate seventy-two (72) scenarios of dyke construction development in the context of low, medium, and high floods that occurred in the VMD to examine the effects of different flood magnitudes on a certain dyke construction area. Based on the model simulation results, we established an evaluation indicator, the so-called Geographical Impact Factor (GIF), to evaluate the impacts of zone-based dyke compartments on the floodwater regimes along the main rivers for different kinds of floods. Our findings revealed different rates of influences on the floodwater levels along the Mekong and Bassac Rivers under different scenarios of zone-based high-dyke developments. GIF is a useful index for scientists and decision-makers in land use planning, especially in rice intensification, in conjunction with flood management for the VMD and for similar deltas worldwide

Data Driven Chiller Plant Energy Optimization with Domain Knowledge

Refrigeration and chiller optimization is an important and well studied topic in mechanical engineering, mostly taking advantage of physical models, designed on top of over-simplified assumptions, over the equipments. Conventional optimization techniques using physical models make decisions of online parameter tuning, based on very limited information of hardware specifications and external conditions, e.g., outdoor weather. In recent years, new generation of sensors is becoming essential part of new chiller plants, for the first time allowing the system administrators to continuously monitor the running status of all equipments in a timely and accurate way. The explosive growth of data flowing to databases, driven by the increasing analytical power by machine learning and data mining, unveils new possibilities of data-driven approaches for real-time chiller plant optimization. This paper presents our research and industrial experience on the adoption of data models and optimizations on chiller plant and discusses the lessons learnt from our practice on real world plants. Instead of employing complex machine learning models, we emphasize the incorporation of appropriate domain knowledge into data analysis tools, which turns out to be the key performance improver over state-of-the-art deep learning techniques by a significant margin. Our empirical evaluation on a real world chiller plant achieves savings by more than 7% on daily power consumption.Comment: CIKM2017. Proceedings of the 26th ACM International Conference on Information and Knowledge Management. 201