• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.3
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• pp.256-263
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• 2021

In this study, blending oils of diesel oil and butanol were used as fuel oil for diesel engine to measure combustion pressure, fuel consumption, air ratio and exhaust gas emission due to various operating conditions such as engine revolution and torque. Using these data, the results of analyzing the engine performance, combustion characteristics and exhaust emission characteristics such as NOx (nitrogen oxides), CO₂ (carbon dioxide), CO (carbon monoxide) and soot were as follows. The fuel conversion efficiency at each load was highest when driven in the engine revolution determined by a fixed pitch propeller law. Except 30% butanol blending oil, fuel conversion efficiency of the other fuel oils increased as the load increased. Compared to diesel oil, using 10% and 20% butanol blending oil as fuel oil was advantageous in terms of thermal efficiency, but it did not have a significant impact on the reduction of exhaust gas emissions. On the other hand, future research is needed on the results of the 20% butanol blending oil showing lower or similar levels of smoke concentration and carbon monoxide emission rate other than those types of diesel oil.

• Journal of Distribution Science
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• v.20 no.12
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• pp.81-87
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• 2022

Purpose: This study aims to explore the relationship between stock liquidity and skewness risk-tail risk (stock price crash risk) in an emerging market, in which problems on liquidity are more severe than in developed markets. Research design, data, and methodology: Based on the Thai market stock exchange over the period of 2000 to 2019, our sample include 13,462 firm-period observations. We employ a panel regression models regarding to five liquidity measures. These five liquidity measures cover three dimensions of liquidity namely the volume-based, price-based, and transaction cost-based measures for the liquidity-tail risk relationship. Results: We find a positively significant relationship between stock liquidity and tail risk in all cases. The finding here shows that the higher the stock liquidity, the larger the tail risk is. Conclusion: As the prior studies show inconclusive effect of stock liquidity on stock price crash risk, we demonstrate that mixed results found in prior studies are probably driven from the type of liquidity measure. The stock liquidity-tail risk association is present in the Stock Exchange of Thailand. The results remain the same regardless of the definition of tail risk and liquidity factors. An endogeneity issue is addressed by employing the two-stage least squares regression.

• Journal of Korea Trade
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• v.23 no.7
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• pp.113-127
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• 2019

Purpose - This paper investigates whether financial crises could be the indicators of capital outflow waves or vice versa in Korea. Korea has experienced two severe financial crises, which are the Asian Crisis and the global financial crisis. Although there were many variables associated with these two remarkable events, one notable variable was gross capital outflows, which had significantly increased around them. Motivated by existing literature which built theoretical frameworks explaining the relationship between capital flight and financial crises, we examine the empirical evidence for this relationship. Design/methodology - We use panel data from 61 countries including Korea from 1980 to 2009 to study the associations between capital flight and diverse financial crises such as banking, currency, debt, and inflation crises. To be specific, we use the complementary log-log model to see whether capital outflow waves are reliable indicators for domestic financial crises. Findings - The results show, first, that banking, currency, and inflation crises are associated with capital flight. Second, debt crises are also associated with capital flight, but the result is not robust to different specifications. And, third, the positive associations between capital flight and crises are mainly driven by banking flows rather than FDI and portfolio flows. Originality/value - This paper is one of a few studies that investigates domestic (not foreign) investors' behavior during financial turmoil. Furthermore, theoretical studies which provide contradictory explanations on the movements of gross capital outflows during financial crises emphasizes the importance of empirical evidence in this paper.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.131-138
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• 2022

The demand for chiller equipment that keeps each machine at a constant temperature to maintain the best possible condition is growing rapidly. PID (Proportional Integral Derivation) control is a popular temperature control method. The error, which is the difference between the desired target value and the current system output value, is calculated and used as an input to the system using a proportional, integrator, and differentiator. Through such a closed-loop configuration, a desired final output value of the system can be reached using only the target value and the feedback signal. Furthermore, various temperature control methods have been devised as the control performance of various high-performance equipment becomes important. Therefore, it is necessary to design for accurate data-driven temperature control for chiller equipment. In this research, support vector regression is applied to the classic PID control for accurate temperature control. Simulated annealing is applied to find optimal PID parameters. The results of the proposed control method show fast and effective control performance for chiller equipment.

• Wind and Structures
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• v.37 no.2
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• pp.95-104
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• 2023

The latest revision of AS/NZS 1170.2 incorporates some new research and knowledge on strong winds, climate change, and shape factors for new structures of interest such as solar panels. Unlike most other jurisdictions, Australia and New Zealand covers a vast area of land, a latitude range from 11° to 47°S climatic zones from tropical to cold temperate, and virtually every type of extreme wind event. The latter includes gales from synoptic-scale depressions, severe convectively-driven downdrafts from thunderstorms, tropical cyclones, downslope winds, and tornadoes. All except tornadoes are now covered within AS/NZS 1170.2. The paper describes the main features of the 2021 edition with emphasis on the new content, including the changes in the regional boundaries, regional wind speeds, terrain-height, topographic and direction multipliers. A new 'climate change multiplier' has been included, and the gust and turbulence profiles for over-water winds have been revised. Amongst the changes to the provisions for shape factors, values are provided for ground-mounted solar panels, and new data are provided for curved roofs. New methods have been given for dynamic response factors for poles and masts, and advice given for acceleration calculations for high-rise buildings and other dynamically wind-sensitive structures.

• Journal of Korean Public Health Nursing
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• v.37 no.1
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• pp.111-124
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• 2023

Purpose: This study aimed to investigate the effects of restorative family circles (RFCs) on empowerment and family support for people with mental illness, and the belief system and caring experience of their families. Methods: This study used a quasi-experiment with a non-equivalent control group pretest-posttest non-synchronized design. Ninety-two dyads of patient-family caregivers were recruited using convenience sampling and assigned to the experimental and control groups. The subjects of the experimental group participated in RFCs consisting of eight 90-minute sessions. Data were collected at three different times (pretest, posttest, follow-up test) and analyzed for the effects of RFC using the 𝑥² test, Fisher's exact test, Mann-Whitney U test for homogeneity between groups, and generalized estimating equation models. Results: The findings of this study showed that there were significant differences in the family support for people with mental illness between the pretest and follow-up test, and also in the belief system and caring experience of the family between the pretest and posttest. Conclusion: This study revealed that family interventions based on restorative justice emphasizing community-driven conflict management could be used in psychiatric mental health nursing care for fostering a cohesive family relationship.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.3
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• pp.217-227
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• 2022

Predicting return and volatility in the global Capital Market during a pandemic is challenging, and it is more difficult for a specific sector, particularly if that sector has a positive outlook. The goal of this research is to look at the impact of COVID-19 on the mean and volatility of the Information Technology Indexes of the best nine technology-driven countries based on return performance using an econometric GARCH model that is widely used. The daily returns of information technology indexes are evaluated for the same from November 2018 to February 2021. Data is taken from Yahoo Finance for CAC Tech (France), DAX Tech (Germany), FTSE All Tech (UK), KOPSI 200 IT (Korea), NIFTY IT (India), S&P 500 IT (US), S&P TSX (Canada), SSE_IT (China) and TOPIX17 (Japan). The results show daily positive mean returns for 8 countries' IT Indices and further, an uptrend in mean daily returns is observed in the crisis period for 6 countries' IT Indices. The exogenous variable COVID-19 which was taken as a regressor for the GARCH model was found to be positively significant for IT indices of all the countries. The overall results confirm the presence of the mean-reverting phenomenon for IT indices of all the countries.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.19-22
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• 2022

In this work, we studied consumers' attractiveness/usefulness perceptions (CAUP) of online commerce product photos when exposed to alternative dark/light user interface (UI) modes. We analyzed time-series EEG data from 31 individuals and performed neuroscience mining (NSM) to ascertain (a) how the CAUP of products differs among UI modes; and (b) which deep learning model provides the most accurate assessment of such neuroscience mining (NSM) business difficulties. The dark UI style increased the CAUP of the products displayed and was predicted with the greatest accuracy using a unique EEG power spectra separated wave brainwave 2D-ConvLSTM model. Then, using relative importance analysis, we used this model to determine the most relevant power spectra. Our findings are considered to contribute to the discovery of objective truths about online customers' reactions to various user interface modes used by various online marketplaces that cannot be uncovered through more traditional research approaches like as surveys.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.1-3
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• 2022

코로나 19 팬데믹으로 인한 4차 산업혁명이 앞당겨지고 초현실, 초실감, 초연결 사회 등의 키워드가 대두되고 언택트(Untact) 시대가 일상생활에 불가항력적으로 접목되면서 몰입감과 흥미성, 유희성을 목적으로 한 콘텐츠들이 다양하게 활성화되었다. 특히, 메타버스(Metaverse) 플랫폼이 빠르게 진화하면서 물리적 현실과 디지털 가상성을 융합한 다중 사용자에게 다양한 경험이 가능한 서비스가 주목받고 있다. 메타버스는 다중 사용자 플랫폼에서 원활한 커뮤니케이션과 대규모 멀티플레이가 가능한 온라인 비디오 게임, 오픈 게임 월드, AR 협업 공간과 호환되는 사회적, 몰입감이 있는 VR(Virtual Reality) 플랫폼 서비스 중 하나이다. 우리는 메타버스 플랫폼 개발 시 필요로 하는 요소기술 및 3D 데이터 획득을 통한 VR 콘텐츠를 설계하고 구현하고자 한다. 1) 콘텐츠 시나리오 및 사용자 인터랙션 설계; 2) 볼류메트릭 캡처를 활용한 실사 기반의 동적(Dynamic) 데이터 생성; 3) 컴퓨터 그래픽 기반 가상공간 설계 및 정적(Static)데이터 요소기술 개발; 4) 가상 현실 공간 데이터와 볼류메트릭 캡처의 실사 데이터 정합; 5) 공간 데이터 시각화 생성 및 모듈형 공간 이동 제어 기능 개발; 최종적으로 6) VR 환경에서의 콘텐츠 구현을 목표로 한다.

• Korea Trade Review
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• v.45 no.6
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• pp.23-43
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• 2020

This study aims at analyzing the interactions between two of the most significant trade stakeholders in Korea, the Trade Ministry and the Legislature, using text network analysis. Tackling seven Action and Plan Reports for Requests from Parliamentary Inspection released by the National Assembly, this paper conducts a topic modelling analysis, particularly focusing on the reports for the three trade-related institutes: the MOTIE headquarter, Korea Trade Insurance Corporation, Korea Trade and Investment Promotion Agency. According to the analysis, such traditional topics of the MOTIE as enterprise, industry, business, management, development were frequently appeared in the reports. Trade-related topics including export, trade, commerce, investment, overseas, domestic, dispute, cooperation, efficiency, negotiation, service, promotion were repeatedly shown. Lastly, a case study on 2019 Parliamentary Inspection Report showed specific trade-related topics and relevant contents that raised issues in that year. This analysis implies that the text data driven from the Parliamentary Inspection Reports between the MOTIE and the National Assembly, can be established as so called 'trade policy information system' which are valuable not only for the two but also the rest of the trade stakeholders in Korea.