• 전기학회논문지
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• 제66권12호
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• pp.1889-1894
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• 2017

Global automobile manufacturers are developing electric vehicles (EVs) to eliminate the pollutant emissions from internal combustion vehicles and to minimize fossil fuel consumptions for the future generations. However, EVs have a disadvantage of shorter traveling distance than that of conventional vehicles. To answer this shortfall, more batteries are installed in the EV to satisfy the consumer expectation for the driving range. However, as the energy capacity of the battery mounted in the EV increases, the amount of heat generated by each cell also increases. Naturally, a better battery thermal management system (BTMS) is required to control the temperature of the cells efficiently because the appropriate thermal environment of the cells greatly affects the power output from the battery pack. Typically, the BTMS is divided into an active and a passive system depending on the energy usage of the thermal management system. Heat exchange materials usually include gas and liquid, semiconductor devices and phase change material (PCM). In this study, an application of PCM for a BTMS was investigated to maintain an optimal battery operating temperature range by utilizing characteristics of a PCM, which can accumulate large amounts of latent heat. The system was modeled using Dymola from Dassault Systems, a multi-physics simulation tool. In order to compare the relative performance, the BTMS with the PCM and without the PCM were modeled and the same battery charge/discharge scenarios were simulated. Number of analysis were conducted to compare the battery cooling performance between the model with the aluminum case and PCM and the model with the aluminum case only.

• 품질경영학회지
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• 제49권3호
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• pp.245-254
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• 2021

Purpose: In order to accurately reach an underwater projectile to a target point, reliable INS and accurate arrangement of INS between master and slave INS is paramount. Unlike terrestrial and aerial environments, underwater projectile will operates in a restricted environment where location information cannot be received or sent through satellites. In this report, we review the factors affecting the transfer alignment of master and slave INS, as well as how to improve the positional error between INS through improved transfer alignment algorithms. Methods: In this work, we propose an improvement algorithm and verify it through simulation and driving test. The simulation confirmed the difference in the transfer alignment azimuth by fitting the MINS and SINS indoors, displacement in posture, and the process of transfer alignment between MINS and SINS through a driving test to confirm algorithm can improve the arrangement. Results: According to this study, reason for the error in the transfer alignment between MINS/SINS is the factors of the system where movements such as roll, pitch, yaw are not inter locked in real time due to the delay in transmit/receive system. And confirm that the improved algorithm has a desirable effect on accuracy. Conclusion: Through this work, it is possible to identify ways to improve the accuracy of underwater projectiles to reach their target points under various underwater environments and launch condition.

• 디지털산업정보학회논문지
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• 제17권1호
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• pp.57-73
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• 2021

The purpose of this study is to analyze the diffusion period and productivity of smartwork in an organization. Firms are increasingly interested in smartwork for non contact work and working from home because of the corona 19. The smartwork is a new technology that changes face-to-face work in an organization. It helps the work of individuals and organizations regardless of time and place. The theoretical background describes the complexity, system thinking, diffusion theory, smart work, organizational resistance, and productivity. This study analyzes the diffusion period and productivity of smart work through business simulation techniques. A simulation study progresses four stages. There are problem definition, hypothesis establishment and causal loop diagram, model construction and verification, and policy evaluation. The simulation models contain an individual's resistance variables organizational investment and leadership variables related to the operation of smartwork. The organizational investment variables include organizational culture, legal system, implement systems and technology investment. The individual resistance variables include cognitive, attitude, structure and technological resistance. The leadership includes leadership interest variables and performance linkage variables. The simulation executed the changes of a people number adopting smart work and the organizational productivity monthly. As a result of the simulation, many organization members have accepted the smart work innovation after 20 months. The organizational productivity through smart work showed very high value after 16 months. In scenario analysis, the individuals' awareness and attitude resistance showed very important variables to productivity and a personal change of smart work adoption. Meanwhile, The organizational investment showed that the high driving-force increased not productivity and the low driving-force showed decreased low productivity. Also, leadership variables showed a powerful driver for changing smart work productivity. The implication of the study has suggested extending complexity, diffusion theory and organization resistance theory based on simulation methods.

• 품질경영학회지
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• 제50권3호
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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.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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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.

• 한국컴퓨터정보학회논문지
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• 제23권7호
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• pp.39-47
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• 2018

This paper confirms the risk of using smartphone through the analysis of collected usage pattern and proposes the smartphone intervention system in risk situations. In order to check the risk of smartphone usage, we made information collecting application and collected smartphone usage pattern from 11 experiment participants for two months. By analyzing smartphone usage pattern, we confirmed that about 12% of smartphone usage is being used in driving, walking, and on the street. In addition, we analyzed the response rate of smartphone notification in risk situations and confirmed that user responds the smartphone notifications in real-time even in risk situations. Therefore, it is required to present a system that intervenes the use of smartphone in order to protect smartphone users in risk situations. In this paper, we classify risk situations of using smartphone. Also, the proposed smartphone intervention system is designed to periodically detect risk situations. In risk situations, smartphone function can be restricted according to user setting of smartphone. And smartphone can be used normally when safe situation is restored.

• 가정과삶의질연구
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• 제23권1호
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• pp.125-137
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• 2005

Information technology is an important driving force that has changed consumer information environments. In order to adjust in the new environments, consumers need an innovative information system. The purpose of this study was to develop a Consumer Information System (CIS). CIS is a device that supports consumer's decision-making process and elevates consumer information competence. The CIS was constructed by the following steps: (1) organization of developers, (2) systematization of consumer information, (3) data loading, (4) integration of consumer database: data warehouse, (5) data distribution, (6) composition of data mart, (7) use of data access tools: data-mining, OLAP, statistical analysis, Q+R, (8) data visualization: web server.

• 품질경영학회지
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• 제42권4호
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• pp.701-716
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• 2014

Purpose: In the paper, I studied success factors and measures for win-win quality management for boosting corporate competitiveness through the achievement of high quality. Methods: As such, to that end, data of companies' win-win quality management activities and Cooperation performance were gathered. Also, I had a literature review and working staffs'opinions were gathered to develop items related to trade dependence, quality cooperation, and mutual trust and cooperation. To develop the questionnaire, sufficient literature survey was conducted, and advice was sought from experts of manufacturing companies which practice Win-Win Cooperation. Results: Based on these previous researches and analysis by structural equation modeling, among trade dependence factors, overall, other factors except financial dependence and some detailed factors were found to have a relatively significant influence relation. Conclusion: The findings of this study suggest that if individual organizations can construct an effective quality improvement system and positively pursue win-win activities, it will contribute greatly to achieving high quality and improving financial performance. However, given the time and regional limits of this study, more in-depth studies need to be conducted on measures for boosting quality competitiveness through Win-Win Cooperation.

• The Journal of Asian Finance, Economics and Business
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• 제9권9호
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• pp.283-289
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• 2022

Public investment is the process of investing capital in projects that serve national interests and thereby create a driving force for economic development in each country. Especially in developing countries, investment capital is limited, so improving the efficiency of public investment becomes a decisive factor for economic development and enhancing the country's status and ultimately making the country a should be rich. Vietnam has a low starting point, has gone through the doi moi process, and has gradually become a middle-income country, and public investment is attracting attention to improve the quality of the country's infrastructure. The objective of this study is to evaluate the factors affecting the effectiveness of public debt management in Vietnam, through a survey of 150 experts with knowledge of public investment and public debt management, using the results of the estimation through the Using SPSS software, the research results show that the monitoring system and human resource quality have an impact on the effectiveness of public debt management. The study could not, however, discover any proof of the influence of institutional quality, geographic location, or accountability on the effectiveness of public debt management. The research also addresses several policy recommendations for Vietnam that would help the country manage its public debt better in the future.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.486-493
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• 2015

In this paper, a battery model for electric vehicle virtual platform was developed. A battery model consisted of a battery cell model and battery thermal management system. A battery cell model was developed based on Randles equivalent circuit model. Circuit parameters in the form of 3D map data was obtained by charge-discharge experiment of Li-Polymer battery in various temperature condition. The developed battery cell model was experimentally verified by comparing voltages. Thermal management system model was also developed using heat generator, heat transfer and convection model, and cooling fan. For verification of the developed battery model in vehicle level, the integrated battery model was applied in to EV(electric vehicle) virtual platform, and virtual driving simulation using UDDS velocity profile was conducted. The accuracy of the developed battery model has been verified by comparing the simulation results from EV platform with the experimental data.