• Journal of Drive and Control
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• v.17 no.4
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• pp.113-124
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• 2020

Most of the work of construction equipment and agricultural machinery is done in off-road conditions. Autonomous driving required in these conditions uses GPS sensors, and PID controllers to control their speed and position. The hydrostatic steering, which is composed of a PSU, hydraulic hoses, and cylinders, rather than a mechanical coupling is used in these equipments. The PSU plays a key role in hydrostatic steering. Precise control of the position under various conditions requires detailed behavioral analysis of the basic components and operation. Two Gerotor PSU is now a commonly used safer option. The components of the PSU can be divided into mechanical and hydraulic actuating elements by its behavior. Since the system is combined by mechanical and hydraulic elements, the modelings are performed using Amesim, which is one of the most effective for the multi-domain dynamic system analysis. To confirm the validity of the model, input torque and pressures are checked with varying steering speed. The opening and the steering speed of normal and newly designed control valve set is investigated with the effect of centering spring force and friction. Finally, simulation results with fully detailed model with two gerotors are analyzed and compared with simple model.

• Structural Engineering and Mechanics
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• v.77 no.6
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• pp.705-720
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• 2021

Reinforced concrete (RC) columns are the primary type of vertical support used in building structures that sustain vertical loads. However, their strength may be insufficient due to fire, earthquake or volatile environments. The load demand may be increased due to new functional usages of the structure. The deformability of concrete columns can be greatly reduced under high axial load conditions. In response, a novel steel encasement that distinguishes from the traditional steel jacketing that is assembled by welding or bolt is developed. This novel strengthening method features easy installation and quick strengthening because direct fastening is used to connect the four steel plates surrounding the column. This new connection method is usually used to quickly and stably connect two steel components by driving high strength fastener into the steel components. The connections together with the steel plates behave like transverse reinforcement, which can provide passive confinement to the concrete. The confined column along with the steel plates resist the axial load. By this way, the axial load capacity and deformability of the column can be enhanced. Eight columns are tested to examine the reliability and effectiveness of the proposed method. The effects of the vertical spacing between adjacent connections, thickness of the steel plate and number of fasteners in each connection are studied to identify the critical parameters which affect the load bearing performance and deformation behavior. Lastly, a theoretical model is proposed for predicting the axial load capacity of the strengthened RC columns.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2960-2973
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• 2022

Since Fukushima nuclear power plant (NPP) accident in 2011, the importance of research on various severe accident phenomena has been emphasized. Particularly, detailed analysis of combustion risk is necessary following the containment damage caused by combustion in the Fukushima accident. Many studies have been conducted to evaluate the risk of local hydrogen concentration increases and flame propagation using computational code. In particular, the potential for combustion by local hydrogen concentration in specific areas within the containment has been emphasized. In this study, the process of flame propagation generated inside a reactor core to containment during a loss of coolant accident (LOCA) was analyzed using MELCOR 2.1 code. Later in the LOCA scenario, it was expected that hydrogen combustion occurred inside the reactor core owing to oxygen inflow through the cold leg break area. The main driving force of the oxygen intrusion is the elevated containment pressure due to the molten corium-concrete interaction. The thermal and mechanical loads caused by the flame threaten the integrity of the containment. Additionally, the containment spray system effectiveness in this situation was evaluated because changes in pressure gradient and concentrations of flammable gases greatly affect the overall behavior of ignition and subsequent containment integrity.

• The Journal of Asian Finance, Economics and Business
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• v.10 no.2
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• pp.281-300
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• 2023

Recently, the call for better accountability and social responsibility from corporations has been regularly voiced, both in the academic literature and in public discussions. This poses a challenge to the existing literature in understanding consumption behaviors to direct them toward sustainable development. This study investigates the purchase intention of Gen Z consumers in Vietnam with green packaging products. Data were collected from 914 respondents by online questionnaire and then analyzed using OLS. The results suggest the significant influence of customers' income and packaging in driving customers' intention to use environmentally-friendly products. Specifically, consumers in a higher income class participate more actively in green purchases. However, problems associated with inadequate packaging are also illustrated, resulting in the poor perception of green messages and poor practice of ecological actions. Besides, subjective norms and green trust are found to be adversely related to green consumer intention. In addition, gender disparity in green behavior is reported, where female consumers show a higher tendency to ecological consumption than their male counterparts. Other demographic factors are also included in the model as control variables, which are age, education, price, environmental literacy, environmental concern, and psychological awareness, but they do not have a significant impact on green purchase intention.

• Journal of Korean Society for Quality Management
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• v.50 no.3
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• pp.533-543
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• 2022

Purpose: The purpose of this study is to identify and resolve the causes of defects in the unmanned aerial vehicle launch system(propulsion wire fracture, rear rail deformation) and to prevent recurrence. Methods: The causes of the two defects were derived through fault tree analysis for each of the two defects and fault reproduction tests. In the case of propulsion wire, the installation of a high speed camera to check the behavior of wire was the driving force behind the defect resolution. Results: The results of this study are as follows; It was determined that the thickness of the washer was less than the maximum tolerance of the pulley was the cause of the propulsion wire fracture defect. Failure to comply with the launch procedure and insufficient safety margin were judged as the cause of the rear rail deformation defect. Accordingly, the configuration was changed to remove each defect. Conclusion: The case of this study was conducted to eliminate defects in the launch system for UAV. The causes of defects were estimated through fault tree analysis. After the configuration change, Structural analysis and launch tests were performed to demonstrate the safety and effectiveness of the modified configuration. As a result, the effect of the modified configuration was verified.

• Journal of Distribution Science
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• v.20 no.1
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• pp.77-85
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• 2022

Purpose: The Covid-19 pandemic has triggered several herd purchase behaviors, and online shopping has been considered a health-related preventative behavior. Thisstudy aimsto the relative impact of health threat beliefs concerning Covid-19 (perceived susceptibility and perceived severity) and herd mentality on consumers' online shopping post-adoption disconfirmation and continuance intention of online shopping. Research design, data and methodology: An internet survey was conducted with Vietnamese consumers, and upon screening, usable data of 292 responses were analyzed using PLS-SEM. Results showed that while herd mentality positively affects disconfirmation, health threat beliefs including perceived susceptibility and perceived severity of Covid-19 do not. Results: Results also provided further support for the notion that disconfirmation is a crucial determinant of post-adoption continuance intention. Moreover, herd mentality also has a significantly negative influence on online shopping post-adoption continuance intention. Conclusions: The research provides evidence supporting the role of herd mentality and post-adoption disconfirmation in driving consumers' intention to continue online shopping. However, the research shows that neither the perceived susceptibility of Covid-19 nor the perceived severity of Covid-19 has significant impact on post-adoption disconfirmation, adding mixed evidence to the application of health belief theory in technology (such as online shopping) adoption.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.122-128
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• 2020

This research investigates how a Virtual Reality (VR)-based simulation could be used to train safe operation skills for forklift operators. Forklift operation is categorized as high-risk work by many occupational health and safety regulators and authorities due to high injury and fatality rates involved with forklifts. Therefore, many safety guidelines have been developed for forklift operators. Typically, forklift operation safety training is delivered based on instructional texts or videos, which have limitations in influencing people's safety behavior. Against this background, we propose a VR-based forklift simulator that can enable safe operation skills training through a feedback system. The training program consists of several modules to teach how to perform the basic tasks of forklift operation, such as driving, loading and unloading, following the safety guidelines. The system provides instantaneous instructions and feedback regarding safe operation. This training system is based on the model of "learning-by-doing". The user can repeat the training modules as many times as necessary before being able to perform the given task without violating any safety guidelines. The last training module tests the user's acquisition of all safety skills required. The user feedback from several demonstration sessions showed the potential usefulness of the proposed training system.

• Journal of Distribution Science
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• v.22 no.5
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• pp.93-104
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• 2024

Purpose: This study used the SORmodel (or cue utilization theory) to examine the impact of expanded quality factorsincluding product quality on customer satisfaction, attitude, and behavioral loyalty. This study examined the moderating effect of gender on the customer satisfaction-attitudinal and behavioral loyalty relationship. Research design, data, and methodology: 364 respondents were collected through an online survey and analyzed using the SmartPLS 4.0 program. Results: The findings show that product quality, along with system quality and service quality, are key determinants of customer satisfaction. In addition, this study shows that the relationship between customer satisfaction and attitudinal loyalty (repurchase and word-of-mouth intention) does not differ depending on gender, but the relationship between customer satisfaction and behavioral loyalty (share-of-visit and share-of-wallet) is stronger for women than for men. Conclusions: This research integrates concepts from environmental psychology and marketing focusing on website quality (information, system, service, and product), as well as satisfaction, attitudinal and behavioral loyalty. Online shopping mall practitioners must systematically analyze and assess the quality of online shopping, a pivotal factor driving customer satisfaction, attitude, and behavioral loyalty. Acknowledging the influence of gender on consumers' online purchasing behavior can aid online retailers in devising tailored e-commerce marketing strategies aimed at attracting and retaining customers.

• Journal of Distribution Science
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• v.22 no.7
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• pp.83-94
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• 2024

Purpose: This article aims to investigate the influence of pricing and distribution on the level of satisfaction and purchase decisions among consumers of pharmaceutical products in Kazakhstan. Research design, data, and methodology: A mixed-methods research design was utilized, incorporating primary and secondary data. Primary data were collected through a survey administered to customers across various pharmacy types, with 100 valid responses analyzed. Secondary data involved an extensive review of existing literature and analysis of national statistics concerning the pharmaceutical market trends from 2008 to 2022. Results: The results reveal a complex relationship between price perceptions and customer satisfaction. A significant segment of the population views current drug prices as high, which affects their satisfaction levels and purchase decisions. The study also highlights the importance of service quality in enhancing customer satisfaction, suggesting that service improvements could mitigate some of the negative perceptions of pricing. Conclusions: This research contributes to the limited but growing body of knowledge on the impact of pricing strategies on consumer satisfaction in the pharmaceutical sectors of developing countries like Kazakhstan. Focusing on economic and behavioral aspects, this study provides a more holistic understanding of the factors driving consumer satisfaction and purchase behaviors in this critical sector.

• Journal of Auto-vehicle Safety Association
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• v.16 no.1
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• pp.6-11
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• 2024

This paper presents a motion planning algorithm of autonomous racing vehicles for mimicking the characteristics of a human driver. Time optimal maneuver of a race car has been actively studied as a major research area over the past decades. Although the time optimization problem yields a single time series solution of minimum time maneuver inputs for the vehicle, human drivers achieve similar lap times while taking various racing lines and velocity profiles. In order to model the characteristics of a specific driver and reproduce the motion, a stochastic motion planning framework based on kernelized motion primitive is introduced. The proposed framework imitates the behavior of the generated reference motion, which is based on a small number of human demonstration laps along the racetrack using Gaussian mixture model and Gaussian mixture regression. The mean and covariance of the racing line and velocity profile mimicking the driver are obtained by accumulating the outputs tested at equidistantly sampled input points. The results confirmed that the obtained lateral and longitudinal motion simulates the driver's driving characteristics, which are feasible for actual vehicle test environments.