• Korean Medical Education Review
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• v.24 no.2
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• pp.156-171
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• 2022

The purpose of this study was to establish a model for constructing longitudinal data for medical school, and to structure cohort and longitudinal data using data from Yonsei University College of Medicine (YUCM) according to the established input-environment-output (I-E-O) model. The study was conducted according to the following procedure. First, the data that YUCM has collected was reviewed through data analysis and interviews with the person in charge of each questionnaire. Second, the opinions of experts on the validity of the I-E-O model were collected through the first expert consultation, and as a result, a model was established for each stage of medical education based on the I-E-O model. Finally, in order to further materialize and refine the previously established model for each stage of medical education, secondary expert consultation was conducted. As a result, the survey areas and time period for collecting longitudinal data were organized according to the model for each stage of medical education, and an example of the YUCM cohort constructed according to the established model for each stage of medical education was presented. The results derived from this study constitute a basic step toward building data from universities in longitudinal form, and if longitudinal data are actually constructed through this method, they could be used as an important basis for determining major policies or reorganizing the curricula of universities. These research results have implications in terms of the management and utilization of existing survey data, the composition of cohorts, and longitudinal studies for many medical schools that are conducting surveys in various areas targeting students, such as lecture evaluation and satisfaction surveys.

• Journal of Korean Physical Therapy Science
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• v.29 no.4
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• pp.1-16
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• 2022

Background: This study was conducted to examine the correlation of VDT, posture and shoulder function among each group divided by according to the neck pain disorder index (NDI) scores for female patients with neck pain. Design: Cross-sectional study. Methods: Fifty adult women with neck pain voluntarily participated in this study and the neck pain disorder index questionnaire, VDT syndrome assessment tool questionnaire, craniovertebral angle, thoracic kyphosis angle, round shoulder posture, pectoralis minor length, shoulder joint hypermobility, and serratus anterior strength tests were conducted respectively. Subjects were divided into two groups where 21 subjects were allocated to the mild pain group whom have rated below 14 points on the NDI scores, and 29 subjects were in the severe pain group, whom have rated above 15 on the NDI score. Results: The study found that in the mean difference between variables in each group, VDT syndrome showed a higher mean score in the severe pain group than the mild pain group (p<0.05). In the group correlation and regression analysis, the mild pain group showed a significant negative correlation between the craniovertebral angle and round shoulder posture (r=-0.467, p<0.05), and the round shoulder posture for craniovertebral angle was shown to have significant positive influence (B=10.162, p<0.05). The severe pain group showed that the NDI and the VDT syndrome had a significant amount of correlation (r=0.520, p<0.01), the VDT syndrome showed significant positive influence (B=0.330, p<0.05), and the craniovertebral angle showed significant negative influence (B=-0.809, p<0.05). It was also shown that shoulder joint hypermobility had a significant negative correlation with the serratus anterior strength (r=-0.437, p<0.01), and that serratus anterior strength had a significant negative influence on shoulder joint hypermobility (B=-4.175, p<0.05). Conclusion: This study is of clinical significance in that it presented variables that should be considered depending on the degree of neck pain in treating patients with neck pain and that it presented patients with not only posture but also the function of the shoulder joint as factors to consider.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.123-123
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• 2023

하천이 바다와 만나는 하구(河口, estuary)지역은 조위의 영향을 강하게 받아 하천 수위의 낙폭이 크고, 하상(河床)의 변동 또한 심하다. 때문에 이러한 감조구간은 홍수위 산정에 있어서도 일반하천에 비해 보다 세심한 주의가 요구된다. 우리나라 4대강 중 한강을 제외한 낙동강, 금강 및 영산강은 하구언 설치로 인해 이미 하구로서의 기능을 상실한 상황이다. 반면 한강 하류 구간은 북한과의 접경지역이라는 지리적, 상황적 특수성으로 인해 하구언 설치가 불가능하였기에 지금까지 감조상태를 유지하고 있다(Park and Baek, 2017). 지금까지 계획홍수위 산정시 일반하천이든 감조하천이든 간에 그 고유의 특성을 고려치 않고 정상-부등류(steady-nonuniform flow) 모의를 하는 것이 일반적인 관례이었다. 하지만 2018년 개정된 하천설계기준에 따르면 감조하천 구간에서는 반드시 부정류(unsteady flow) 모의를 수행하도록 규정하고 있다. 이에 따라 2020년 고시된 한강(팔당댐~하구) 하천기본계획(변경) 보고서에는 부정류해석을 통한 홍수위 산정분이 수록되어 있다. 문제는 "한강하구는 서해조석의 영향을 받는 감조하천이기는 하나 계획홍수량 유하시 한강에 미치는 조위의 영향은 미미하므로..."라는 결론을 도출하면서 부정류해석 결과 대신 부등류해석 결과를 계획홍수위로 결정했다는 것이다. 본 연구에서는 한강의 종점 유도지점을 기점으로 조석을 하류단 경계조건으로 부여하는 부정류 해석을 수행하여 한강하천기본계획(2020)의 홍수위와 비교하였다. 그 결과 본 연구에서 산정한 홍수위가 하구에서부터 신곡수중보 하류구간까지는 하천기본계획의 그것과 상당한 차이를 보였다. 한강하류 구간은 계획홍수량 발생시에도 조석의 영향을 받는 감조구간이므로 고시된 계획홍수위의 재검토가 필요해 보인다.

• Journal of The Korea Institute of Healthcare Architecture
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• v.29 no.3
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• pp.37-44
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• 2023

Purpose: To decrease cross-infection, it's essential to analyze the spatial composition of the 'PPE doffing area'. Instead of solely relying on manpower standards, we should focus on responding to infectious diseases within the context of space planning. By doing so, we can lower the risk for healthcare workers' infection and ensure a level of safety in various environmental changes or new manpower input situations. Methods: This analysis is conducted specifically for facilities with negative pressure isolation wards. Additionally, interview surveys to obtain feedback from healthcare workers and incorporate their expertise into the design of the 'PPE doffing area' have been carried. Results: In a PPE doffing area, the standard spaces include a PPE doffing room, a shower room, and a clothing room. Depending on the facility environment or the level of infectious diseases, a Decontamination room or Anteroom can be optionally added. Healthcare workers who remove their PPE in the PPE doffing room should avoid re-entering the Negative pressure room. The shower room is often underutilized. When planning for a future PPE doffing area, an aisle space or passageway must be included even if a shower room is planned. Implications: This study examined the space used by healthcare workers rather than patients, with a focus on infection prevention through architectural planning rather than individual efforts. However, the investigation was limited to facilities that have been converted from general wards to negative pressure isolation wards, so it cannot be generalized to all infectious disease facilities.

• Korean Journal of Materials Research
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• v.32 no.12
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• pp.553-559
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• 2022

In this work, the ablation behavior of monolith ZrB₂-30 vol%SiC (Z30S) composites were studied under various oxy-acetylene flame angles. Typical oxidized microstructures (SiO₂/SiC-depleted/ZrB₂-SiC) were observed when the flame to Z30S was arranged vertically. However, formation of the outmost glassy SiO₂ layer was hindered when the Z30S was tilted. The SiC-depleted region was fully exposed to air with reduced thickness when highly tilted. Traces of the ablated and island type SiO₂ were observed at intermediate flame angles, which clearly verified the effect of flame angle on the ablation of the SiO₂ layer. Furthermore, the observed maximum surface temperature of the Z30S gradually increased up to 2,200 ℃ proving that surface amorphous silica was continuously removed while monoclinic ZrO₂ phase began to be exposed. A proposed ablation mechanism with respect to flame angles is discussed. This observation is expected to contribute to the design of complex-shaped UHTC applications for hypersonic vehicles and re-entry projectiles.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.761-768
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• 2022

In the hope of realizing carbon neutrality, Korea has established the goal of expanding the supply of hydrogen electric vehicles through a roadmap to revitalize the hydrogen economy. A prerequisite for successful supply expansion is securing the safety of hydrogen electric vehicles. Certain parts, such as the hydrogen transport pipe and tank, in hydrogen electric vehicles are exposed to high-pressure hydrogen gas over long periods of time, so the hydrogen enters the grain boundary of material, resulting in a degradation of the parts referred to as hydrogen embrittlement. In addition, since the safety of parts utilizing hydrogen varies depending on the type of material used and its environmental characteristics, the necessity for the enactment of a hydrogen embrittlement regulation has emerged and is still being discussed as a Global Technical Regulation (GTR). In this paper, we analyze a hydrogen compatibility material evaluation method discussed in GTR and present a direction for the development of Korean-type hydrogen compatibility material evaluation methods.

• Nuclear Engineering and Technology
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• v.27 no.2
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• pp.216-225
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• 1995

Simulation for a dynamic analysis of the electrolytic preparation of U(IV) in two-phases system, which consisted of mass transfer of U(VI) from TBP phase into HNO$_3$ solution and electrolytic re-duction of U(VI) to U(IV) at a cathode in aqueous phase, was carried out in order to establish the most suitable operating condition and best electrode area as basic design data for the system. It was found that maintaining an appropriate mass transfer rate was more significant rather than enlarging the surface area of the cathode for more effective production yield of U(IV). The electrode area and the operation time affected deeply the production composition of U(IV) in the resulting aqueous phase. And optimal electrode areas ore evaluated to meet production criteria of U(IV) of resulting solution in several system conditions. Though about 0.37M HNO$_3$ was preferable to prepare the solution of U(IV), nitric acid concentration should be higher than 0.5M to prevent a hydrolysis of U(IV) in the aqueous phase.

• Journal of the Korean Geotechnical Society
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• v.24 no.9
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• pp.33-40
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• 2008

This paper describes the performance of ground improvement project using prefabricated vertical drains of condition, in which approximately 10m dredged fill overlies original soft foundation layer in the coastal area composed of soft marine clay with high water content and high compressibility. From field monitoring results, excessive ground settlement compared with predicted settlement in design stage developed during the following one year. In order to predict the final consolidation behavior, recalculation of consolidation settlements and back analysis using observed settlements were conducted. Field monitoring results of surface settlements were evaluated, and then corrected because large shear deformation occurred by construction events in the early stages of consolidation. To predict the consolidation behavior, material functions and in-situ conditions from laboratory consolidation test were re-analyzed. Using these results, height of additional embankment is estimated to satisfy residual settlement limit and maintain an adequate ground elevation. The recalculated time-settlement curve has been compared with field monitoring results after additional surcharge was applied. It might be used for verification of recalculated results.

• Journal of The Korea Institute of Healthcare Architecture
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• v.29 no.2
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• pp.39-48
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• 2023

Purpose: In Korea, the increase rate of the number of mentally ill patients increases, and the hospitalization period for severely mentally ill patients to stay in acute wards is long and the re-hospitalization rate is high. In order to improve the dignity of patients with acute mental illness and to plan a therapeutic environment for this, this study attempted to present a basic framework of spacial planning for establishing guidelines for psychiatric acute ward in general hospitals. Methods: By analyzing the acute psychiatric ward guidelines of the UK, Australia, and the US., this study analyzed the areas and required rooms of psychiatric acute ward in general hospitals, as well as the net floor area of each room, and the connection between the rooms. Results: As a result of the study, the basic framework for the ward areas and the required rooms, the net floor areas of the rooms, and the connection between the rooms were presented for the establishment of guidelines for the psychiatric acute ward in general hospitals. Implication: The results of the study will be used as a basic framework of space planning for establishing of guidelines for the psychiatric acute ward in general hospitals and will contribute to the establishment of detailed guidelines based on the space configuration through surveys and analysis of space use status, operation status, and expert interviews in Korea.

• Asia-Pacific Journal of Business
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• v.14 no.1
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• pp.73-91
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• 2023

Purpose - The purpose of this study is to re-examine the disclosure effect of stock splits and long-term performance after stock splits using stock split data over the past 10 years, and infer the motivation (signal or opportunism) of stock splits. In addition, we focus on exploring the determinants of the short- and long-term market response to stock splits. Design/methodology/approach - We measure the short-term market response to a stock split and the long-term stock performance after the stock split announcement using the event study method. We analyze whether there is a difference in the long-term and short-term market response to a stock split according to various company characteristics through univariate analysis and regression analysis. Findings - In the case of the entire sample, a statistically significant positive excess return is observed on the stock split announcement date, and the excess return during the 24-month holding period after the stock split do not show a difference from zero. In particular, the difference between short-term and long-term returns on stock splits is larger in companies with a large stock split ratio, small companies, large growth potential, and companies with a combination of financial events after a stock split. Research implications or Originality - The results of this study suggest that at least the signal hypothesis for a stock split does not hold in the Korean stock market. On the other hand, it suggests that there is a possibility that a stock split can be abused by the manager's opportunistic motive, and that this opportunism can be discriminated depending on the size of the stock split, corporate characteristics, and financing plan.