• 산경연구논집
• /
• 제13권1호
• /
• pp.23-32
• /
• 2022

Purpose: This study used ESG grade, but defined AESG, adjusted to the size of a company and examines whether it can be used as an investment strategy. Research design, data and methodology: The analysis sample in this study is a company that has given an ESG rating among companies listed on the Korea Stock Exchange. We examine the results through portfolio analysis and Fama-macbeth regression analysis. Results: As result of examining the long-only performance and the long-short performance by constructing quintile portfolios, it was observed that a significant positive return was shown. It was observed that there was an alpha that could not be explained in asset pricing models. Also, AESG had a return prediction effect in the result of a Fama-Macbeth regression that controlled corporate characteristic variables in individual stocks. Next, we confirmed AESG's usage through various portfolio composition. In the portfolio optimization, the Risk Efficient method was the most superior in terms of sharpe ratio and the construct multi-factor model with Value, Momentum and Low Vol showed statistically significant performance improvement. Conclusions: The results of this study suggest that it can be helpful in ESG investment to reflect the ESG rating of relatively small companies more through the scale adjustment of the ESG rating (i.e.AESG).

• 한국경제지리학회지
• /
• 제14권2호
• /
• pp.157-175
• /
• 2011

본 연구는 미국의 헬스케어 REITs의 성과 및 운영 특성을 살펴보고, 이를 통해 국내 실버산업에의 활용 방안을 모색하는 것을 목적으로 한다. 본 연구의 결과를 요약하면 다음과 같다. 첫째로, 미국의 헬스케어 REITs의 현황 및 성과를 보면, 2007년 이후 평균적인 REITs보다 양호한 성과를 보이고 있으며, 이러한 성과를 바탕으로 시장 규모 면에서 전체 REITs에서 차지하는 비중을 높이고 있다. 이러한 헬스케어 REITs가 초과 성과를 보이는 데는 실버산업의 고속 성장도 영향을 미쳤지만, 판매 후 재임대와 3차 순임대차 구조를 활용한 REITs의 전략도 한 몫을 한 것으로 판단된다. 둘째로, 미국 헬스케어 REITs는 자산유형의 관점에서는 선택과 집중전략을, 투자지역의 관점에서는 투자지역 다변화 전략을 사용하는 것으로 나타났다. 셋째로, 이러한 분석결과를 볼 때, 헬스케어 REITs는 국내의 실버산업에 충분히 활용 가능성이 있음을 확인하였으며, 이에 헬스케어 REITs, 즉 부동산투자회사를 효과적으로 활용하기 위한 방안을 제시하였다.

• 보건행정학회지
• /
• 제27권2호
• /
• pp.114-120
• /
• 2017

The hospital standardized mortality ratio (HSMR) is a widely used generic measure for assessing quality of hospital care in many countries. However, the validity of HSMR as a quality indicator is still controversial. We critically reviewed characteristics of HSMR and suggested how to use HSMR as a quality indicator in the Korean setting. The association between HSMR and other quality measures of hospital care is inconclusive. In addition current HSMR model has shortcomings in risk adjustment because of the lack of clinical data, accuracy of disease coding, coding variation among hospitals, end-of-life care issues, and so on. Therefore, HSMR should be used as an indicator for improvement, not for judgement such as public reporting and pay-for-performance. More efforts will be needed to tackle practical and methodological weaknesses of HSMR in the Korean setting.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• 제24권3호
• /
• pp.124-131
• /
• 2013

South Korea is changing into a multi-cultural society, due to an increase in international marriage, foreign workers and transcultural immigration. In addition, the number of North Korean defectors entering South Korea has increased and now, there are approximately 25000. Therefore, this review have focused on a research that pertains to adaptation and mental health concerns of their children. Children who have immigrated themselves or whose parents have immigrated, might experience language barriers, difficulties in school adjustment, identity confusion and mental health problems. However, their academic performance and developmental status are known to be variable and be affected by socioeconomic status and their parents' educational level. Studies that evaluated the psychological problems of North Korean adolescent refugees' indicated the need for interests in both emotional and behavioral problems. The risk factors of North Korean adolescent refugees' mental health are suggested to be past traumatic experiences, long duration of defection and short period of adaptation. When mental health professionals provide assessment and treatment, they should consider the pre- and post-migration experiences & cultural background that affect the illness behaviors and attitudes toward mental illnesses. Lastly, the majority of children with multi-cultural background are still under an adolescent period and we should follow up with long-term perspectives.

• 한국학교보건학회지
• /
• 제29권2호
• /
• pp.90-97
• /
• 2016

Purpose: The purpose of this study was to investigate the relationship between sleep timing and depressive mood in Korean adolescents. Methods: The study analyzed the data from the 2007~2015 Korea Youth Risk Behavior Web-based Survey. A total of 541,693 students in grades 7~12 were included in the final analysis. Multivariable logistic regression was used to examine their sleep timing and depressive mood, adjusted for sex, grade, region, socioeconomic status, academic performance, alcohol, smoking and physical activity. Sleep duration and sleep quality were also included in our model to identify whether or not the effect of sleep timing on depression is mediated by sleep duration or sleep quality. Results: The prevalence of depressive mood was 32.7% and the mean sleep timing was 12:13 AM. After adjustment for eligible covariates, the association between sleep timing and depressive mood showed a J-shaped curve. Adolescents who slept at 8 pm~10 pm were 39% more likely to be depressive (OR = 1.39, 95% CI 1.30~1.40) and at 3 am~ 4 am were 67% more likely to be depressive (OR=1.67, 95% CI 1.64~1.70) than adolescents who slept at 11 pm~12 am. These associations persisted after being adjusted for sleep duration and sleep quality. Conclusion: Sleep timing was related to depression in adolescents, independent of sleep duration and sleep quality. It appears that there is a certain sleep timing beneficial to mental health of adolescents.

• 산업경영시스템학회지
• /
• 제47권2호
• /
• pp.30-39
• /
• 2024

This study introduces a novel approach for identifying potential failure risks in missile manufacturing by leveraging Quality Inspection Management (QIM) data to address the challenges presented by a dataset comprising 666 variables and data imbalances. The utilization of the SMOTE for data augmentation and Lasso Regression for dimensionality reduction, followed by the application of a Random Forest model, results in a 99.40% accuracy rate in classifying missiles with a high likelihood of failure. Such measures enable the preemptive identification of missiles at a heightened risk of failure, thereby mitigating the risk of field failures and enhancing missile life. The integration of Lasso Regression and Random Forest is employed to pinpoint critical variables and test items that significantly impact failure, with a particular emphasis on variables related to performance and connection resistance. Moreover, the research highlights the potential for broadening the scope of data-driven decision-making within quality control systems, including the refinement of maintenance strategies and the adjustment of control limits for essential test items.

• 대한안전경영과학회지
• /
• 제22권1호
• /
• pp.23-32
• /
• 2020

There has been a significant decline in the number of rail accidents in Korea since system safety management activities were introduced. Nonetheless, analyzing and preventing human error-related accidents is still an important issue in railway industry. As a railway system is increasingly automated and intelligent, the mechanism and process of an accident occurrence are more and more complicated. It is now essential to consider a variety of factors and their intricate interactions in the analysis of rail accidents. However, it has proved that traditional accident models and methods based on a linear cause-effect relationship are inadequate to analyze and to assess accidents in complex systems such as railway systems. In order to supplement the limitations of traditional safety methods, recently some systemic safety models and methods have been developed. Of those, FRAM(Functional Resonance Analysis Method) has been recognized as one of the most useful methods for analyzing accidents in complex systems. It reflects the concepts of performance adjustment and performance variability in a system, which are fundamental to understanding the processes of an accident in complex systems. This study aims to apply FRAM to the analysis of a rail accident involving human errors, which occurred recently in South Korea. Through the application of FRAM, we found that it can be a useful alternative to traditional methods in the analysis and assessment of accidents in complex systems. In addition, it was also found that FRAM can help analysts understand the interactions between functional elements of a system in a systematic manner.

• 한국안전학회지
• /
• 제36권1호
• /
• pp.36-43
• /
• 2021

Effective leadership in safety performance, such as safety leadership, has received attention as a factor that greatly affects safety performance in various high-risk industrial environments. Based on prior research, this study aims to analyze the impact relationship between safety leadership, safety observance, safety education, and safety culture to reveal the effectiveness of safety leadership. In addition, this study will examine the effects of safety leadership on safety observance and safety education to identify the effects of safety understanding. For this purpose, a survey was conducted with employees of an aviation manufacturing company in Gyeongnam. For verification, a positive factor analysis, correlation analysis, and structural equation analysis were conducted using the AMOS 21.0 program. This study's findings show that, first, safety leadership has a positive and significant impact on safety observance and safety education. Second, safety leadership was found to have a direct impact on organizations' safety culture. Third, although safety observance has significant positive effects on safety culture, safety education has often been rejected. Finally, after verifying the control effect of safety understanding, this study uncovered the presence of an adjustment effect in the effect of safety leadership on safety observance. Therefore, based on the results of this study, theoretical and practical implications suggest that through the exercise of safety leadership, managers can improve their organizations' safety culture by increasing organizations' compliance with safety observance and/or acceptance of safety education.

• Korean Circulation Journal
• /
• 제52권8호
• /
• pp.623-631
• /
• 2022

Background and Objectives: Pulmonary valve replacement (PVR) is the most common operation in adults with congenital heart disease (CHD). There is controversy regarding the best bioprosthesis. We compare the performance of stented bioprosthetic valves (the Mosaic [Medtronic^TM] porcine pericardial against Carpentier Perimount Magna Ease [Edwards^TM] bovine) in pulmonary position in patients with CHD. Methods: Between January 1999 and December 2019, all the PVRs were identified from hospital databases in 2 congenital heart centres in Spain. Valve performance was evaluated using clinical and echocardiographic criteria. Propensity score matching was used to balance the 2 treatment groups. Results: Three hundred nineteen patients were retrospectively identified. After statistical adjustment, 79 propensity-matched pairs were available for comparison Freedom from reintervention for the porcine cohort was 98.3%, 96.1%, and 91.9% at 3, 5, and 10 years and 100%, 98%, and 90.8% for the bovine cohort (p=0.88). Freedom from structural valve degeneration (SVD) for the porcine cohort was 96.9%, 92.8% and 88.7% at 3, 5, and 10 years and 100%, 98%, and 79.1% for the bovine cohort (p=0.38). Bovine prosthesis was associated with a reintervention hazard ratio (HR), 1.12; 95% confidence intervals (CIs), 0.24-5.26; p=0.89 and SVD HR, 1.69 (0.52-5.58); p=0.38. In the first 5 years, there was no difference in outcomes. After 5 years, the recipients of the bovine bioprosthesis were at higher risk for SVD (reintervention HR, 2.08 [0.27-16.0]; p=0.49; SVD HR, 6.99 [1.23-39.8]; p=0.03). Conclusions: Both bioprosthesis have similar outcomes up to 5 years, afterwards, porcine bioprosthesis seem to have less SVD.

• Advances in aircraft and spacecraft science
• /
• 제5권2호
• /
• pp.225-237
• /
• 2018

The difficulties of satellite vibration testing are due to the commonly expressed qualification requirements being incompatible with the limited performance of the entire controlled system (satellite + interface + shaker + controller). Two features cause the problem: firstly, the main satellite modes (i.e., the first structural mode and the high and low tank modes) are very weakly damped; secondly, the controller is just too basic to achieve the expected performance in such cases. The combination of these two issues results in oscillations around the notching levels and high amplitude beating immediately after the mode. The beating overshoots are a major risk source because they can result in the test being aborted if the qualification upper limit is exceeded. Although the abort is, in itself, a safety measure protecting the tested satellite, it increases the risk of structural fatigue, firstly because the abort threshold has been already reached, and secondly, because the test must restart at the same close-resonance frequency and remain there until the qualification level is reached and the sweep frequency can continue. The beat minimum relates only to small successive frequency ranges in which the qualification level is not reached. Although they are less problematic because they do not cause an inadvertent test shutdown, such situations inevitably result in waiver requests from the client. A controlled-system analysis indicates an operating principle that cannot provide sufficient stability: the drive calculation (which controls the process) simply multiplies the frequency reference (usually called cola) and a function of the following setpoint, the ratio between the amplitude already reached and the previous setpoint, and the compression factor. This function value changes at each cola interval, but it never takes into account the sensor signal phase. Because of these limitations, we firstly examined whether it was possible to empirically determine, using a series of tests with a very simple dummy, a controller setting process that significantly improves the results. As the attempt failed, we have performed simulations seeking an optimum adjustment by finding the Least Mean Square of the difference between the reference and response signal. The simulations showed a significant improvement during the notch beat and a small reduction in the beat amplitude. However, the small improvement in this process was not useful because it highlighted the need to change the reference at each cola interval, sometimes with instructions almost twice the qualification level. Another uncertainty regarding the consequences of such an approach involves the impact of differences between the estimated model (used in the simulation) and the actual system. As limitations in the current controller were identified in different approaches, we considered the feasibility of a new controller that takes into account an estimated single-input multi-output (SIMO) model. Its parameters were estimated from a very low-level throughput. Against this backdrop, we analyzed the feasibility of an LQG control in cancelling beating, and this article highlights the relevance of such an approach.