• Smart Structures and Systems
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• 제21권5호
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• pp.571-582
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• 2018

Track irregularities of high-speed Maglev lines have significant influence on ride comfort. Their adjustment is of key importance in the daily maintenance of these lines. In this study, an adjustment method is proposed and track irregularities analysis is performed. This study considers two modules: an inspection module and a vehicle-guideway coupling vibration analysis module. In the inspection module, an inertial reference method is employed for field-measurements of the Shanghai high-speed Maglev demonstration line. Then, a partial filtering, integration method, resampling method, and designed elliptic filter are employed to analyze the detection data, which reveals the required track irregularities. In the analysis module, a vehicle-guideway interaction model and an electromagnetic interaction model were developed. The influence of the measured line irregularities is considered for the calculations of the electromagnetic force. Numerical integration method was employed for the calculations. Based on the actual field detection results and analysis using the numerical model, a threshold analysis method is developed. Several irregularities modalities with different girder end's deviations were considered in the simulations. The inspection results indicated that long-wavelength irregularities with larger girder end's deviations were the dominant irregularities. In addition, the threshold analysis of the girder end's deviation shows that irregularities that have a deviation amplitude larger than 6 mm and certain modalities (e.g., M- and N-shape) are unfavorable. These types of irregularities should be adjusted during the daily maintenance.

• 자원ㆍ환경경제연구
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• 제17권2호
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• pp.213-233
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• 2008

현재 한국전력이 시행하고 있는 하절기 부하관리 프로그램의 성과를 평가함에 있어, 해당 프로그램이 시행되지 않은 상태의 수요가 확인되지 않은 상태에서 단순 합산한 것임에도 불구하고 이 크기의 전체를 수요관리 효과로 집계하고 있다. 본 연구는 이러한 문제에 대해, 이들 프로그램 중에서 가장 비중이 큰 두 가지 프로그램-휴가보수기간 조정제도와 자율절전제도-이 하절기 피크 시간대인 오후 2시~4시 사이의 전력수요에 얼마나 큰 영향을 미치는지를 계량적으로 분석한다. 연구 결과에 의하면 이들 두 제도의 효과를 따로 분석할 경우에는 휴가보수기간 조정제도는 보된 실적치 1kW당 실제로 피크 시간대 전력수요가 시간당 0.53kW만큼 감소하였으며, 자율절전의 경우 실적치 1kW당 피크 시간대 전력수요는 시간당 0.57kwh만큼 감소하였다. 이들 결과는 이들 수요관리 프로그램들이 실제로 피크부하를 감소시키는 데에 상당한 효과가 있음을 보여 준다. 그러나 이 두 제도의 효과를 한꺼번에 분석하는 경우에는 각각의 효과가 크게 약해짐을 볼 수 있었다.

• Clinical and Experimental Reproductive Medicine
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• 제48권3호
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• pp.262-267
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• 2021

Objective: Progesterone application for luteal phase support is a well-established concept in in vitro fertilization (IVF) treatment. Water-soluble subcutaneous progesterone injections have shown pregnancy rates equivalent to those observed in patients receiving vaginal administration in randomized controlled trials. Our study aimed to investigate whether the results from those pivotal trials could be reproduced in daily clinical practice in an unselected patient population. Methods: In this retrospective cohort study in non-standardized daily clinical practice, we compared 273 IVF cycles from 195 women undergoing IVF at our center for luteal phase support with vaginal administration of 200 mg of micronized progesterone three times daily or subcutaneous injection of 25 mg of progesterone per day. Results: Various patient characteristics including age, weight, height, number of oocytes, and body mass index were similar between both groups. We observed no significant differences in the clinical pregnancy rate (CPR) per treatment cycle between the subcutaneous (39.9%) and vaginal group (36.5%) (p=0.630). Covariate analysis showed significant correlations of the number of transferred embryos and the total dosage of stimulation medication with the CPR. However, after adjustment of the CPR for these covariates using a regression model, no significant difference was observed between the two groups (odds ratio, 0.956; 95% confidence interval, 0.512-1.786; p=0.888). Conclusion: In agreement with randomized controlled trials in study populations with strict selection criteria, our study determined that subcutaneous progesterone was equally effective as vaginally applied progesterone in daily clinical practice in an unselected patient population.

• 한국콘텐츠학회논문지
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• 제22권1호
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• pp.545-556
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• 2022

본 연구는 일상생활 수행능력의 제한이 노인의 우울에 영향을 미치는 과정에서 가족 및 요양보호사의 도움이 조절효과를 갖는지 확인하는데 있다. 이를 위해 한국복지패널 15차 자료(2020년)를 기반으로, 65세 이상 노인 4,214명을 대상으로 기술통계, 평균차이분석, 상관관계분석, 회귀분석, 조절효과분석을 실시하였다. 연구결과는 다음과 같다. 첫째, 일상생활 수행능력의 제한은 노인의 우울에 유의한 영향을 미치는 것으로 나타났다. 둘째, 일상생활 수행능력의 제한과 노인의 우울 간에 가족의 도움은 노인의 우울을 완화하는 조절변수로서 기능하는 것으로 나타났다. 셋째, 일상생활 수행능력의 제한과 노인의 우울 간에 요양보호사의 도움은 노인의 우울을 완화하는 조절변수로 기능하지 않는 것으로 나타났다. 이러한 결과를 근거로 함의를 도출하고 정책적 제언을 제시하였다.

• 대한간호학회지
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• 제40권1호
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• pp.110-118
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• 2010

Purpose: To develop outcome indicators of urinary incontinence to measure quality of care in long term care hospitals in Korea. Methods: The draft indicators of urinary incontinence were developed from a literature review and clinical expert panel. A survey of medical records of 280 patients in 20 hospitals was conducted to test inter-rater reliability. Statistical analysis was done to test risk adjustment criteria, variation between hospitals, and stability of indicators, using assessment data from 77,918 patients in 623 hospitals. Results: The inter-rater reliability of items was high (Kappa range: 0.66- 0.92). Severe cognitive impairment (odds ratio [OR]: 3.15, confidence interval [CI]: 3.03-3.26) and total mobility activities of daily living (ADLs) dependency (OR: 4.85, CI: 4.72-4.98) increased the prevalence of urinary incontinence, thus they proved to be significant criteria to stratify high and low risk groups. The prevalence for low risk showed more substantial variation than the high risk group. The indicators were stable over one month. Conclusion: This study demonstrated the feasibility of outcome indicators of urinary incontinence. Improving the reliability of the patient assessment tool and refining the indicators through validation study is a must for future study.

• 한국학교보건학회지
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• 제33권3호
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• pp.213-221
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• 2020

Purpose: The purpose of this study was to investigate adjustment experiences of nursing students in the face of COVID-19. Methods: The subjects were 4 focus groups consisting of a total of 20 participants, including 18 nursing students and 2 professors. From July to August 2020, focus group interviews were conducted. Results: We identified 15 sub-themes and 4 hemes. The 4 themes were sudden and new situation, changes in daily life due to non-face-to-face contact, becoming in an unfamiliar life, rising to the challenge of the new normal. Conclusion: Participants were experiencing difficult situations, accepting and recognizing them as challenges. It is necessary to conduct further research on how college students experiencing a crisis accept the situation and how they think about it, according to their major. In addition, since this research was conducted through focus group interviews, it is necessary to conduct further research using another research method.

• 아태비즈니스연구
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• 제14권1호
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• pp.351-364
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• 2023

Purpose - This study examines the effects of Dubai oil price and the volatility on the asymmetry of domestic gasoline price adjustment. Additionally, the study investigates the effects of "Altteul" gas-station and tax-cut policies on asymmetry. Design/methodology/approach - Firstly, the study calculates proxies for asymmetry and volatility of each window(every 3-month) by error-correction model and GARCH(1, 1) using daily domestic gas price and Dubai oil price from 2008/04/15 to 2022/12/31. Secondly, the study investigates the effects of the increasing rate of Dubai oil price, volatility, "Altteul" gas-station and tax-cut policies on asymmetry. The autoregressive distributed lag regression model is employed for estimations. Findings - The study finds that changes in the increasing rate of Dubai oil price and both types of volatility of Dubai oil price increase asymmetry. While "Altteul" gas-station and tax-cut policies decrease asymmetry. Additionally, the study fails to find that asymmetry in the Korean gasoline market in the estimation with total observations. Research implications or Originality - An increase in Dubai oil price volatility means an increase in cost uncertainty for gas-station owners. Since cost uncertainty is a kind of financial risk, the increase in volatility reinforces the asymmetry. The study provides supporting evidence for the idea.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1689-1694
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• 2004

This study was conducted to develop a novel adjustment factors for 305 days using 138,103 lactation records and 1,770,764 daily records, which were based on environmental circumstances such as herd year, season, age at calving, dry period and lactating stages. The present study showed that the change of persistency of cows at the first parity from total lactacting characteristics was slowly processed, while it was rapidly changed in cows at the second parity stage. Particularly, there was an outstanding difference between the first and second parity cows. Milk yield and composition increased as the age at calving was increased. In addition, milk yield and composition were higher at the first parity on fall compared with others, and those were higher at the more than second parity on fall and winter compared with other parity stages and seasons. The cow of dry group was included into lactating records of more than second parity stage. The data indicated that optimal results arose from 45-70 days of dry period. Milk yield was decreased when dry period was longer or shorter than 45-70 days. The lactating days were divided into 17, 28 and 38 stages to compare the multiplicative correction factors. The factor was effective at 28 stages on the first parity. The total correlation coefficients were 0.93832, 0.95058 and 0.95076 at the present correction factor, 17 stage and 28 stage, respectively. At second parity, the factor was higher in dry group 1 and 3 at 17 stage, and it was higher in dry group 2 at 28 stage compared with others. Therefore, the present study showed that the percent squared bias (PSB), which was calculated from the novel correction factor, was better than previously used correction factors. Also, the present study indicated that the bias of the novel correction factor was improved, and this factor could be more accurate compared with others.

• 가정과삶의질연구
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• 제28권6호
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• pp.81-94
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• 2010

This qualitative research was designed to explore the use of housing among Korean Chinese people in Harbin, China. Focusing on the use which based on the epistemology of housing adjustment, this was particularly designed to examine its cultural assimilation and acculturation on the way of life course, it employed the in-depth interview on the oral history of 5 interviewees in their 60s and 70s, individualized interviews were conducted from May 28 to 31 in 2010. Key findings were summarized as follows; 1. The free market reform in China resulted in privatization that allowed respondents to become homeowners, and the ownership was viewed as part of family asset centered upon a sense of solidarity. 2. Although homeowners in multi-story houses were responsible to decorate interior spaces, the common features in using interior spaces were found: entrance had no thresholds; kitchen was small, lack of storage cabinets, tile-flooring; washers were installed inside bathroom; and newly built apartment didn't have proper space to store Korean fermented foods. It was observed that housing adaptation outweighed housing adjustment. Those who used to live in Chinese houses with indoor-wearing-shoes or Russian houses with indoor-wearing-slippers were receptive to the use of dining table and bed, and the community heating system discouraged the use of individual electric water heater because of high electricity cost. 3. In daily life, eating habit wasn't much changed to the Chinese style, meals were shared, dish sterilizer was popular, and Kimchi fridge wasn't used. Because of the influence of the Chinese culture, such Korean traditions as ancestral rites and bedroom allocation tradition faded away, but traditional family values remained unchanged. In conclusion, Korean Chinese people experience normative housing deficits and adaptation selectively incurred. It's implied that residential design meets the needs resulting from the dual culture in terms of cultural assimilation and acculturation.

• 한국항만경제학회지
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• 제39권2호
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• pp.129-141
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• 2023

본 연구는 오차교정모형을 활용해 건화물선과 유조선 일간 해상운임의 동태적 특성과 예측 정확도를 분석한다. 공적분된 시계열 자료의 오차를 계산하기 위해 본 연구는 공통 확률적 추세 모형(Common Stochastic Trend Model, CSTM 모형)과 벡터오차교정모형(Vector Error Correction Model, VECM 모형)을 활용한다. 먼저, CSTM 모형의 오차를 사용한 오차교정모형이 VECM 모형의 경우보다 교정계수(adjustment speed coefficient)가 경제학적 이론에 더 부합하는 결과를 보인다. 나아가 조정결정계수(adjR²) 측면에서도 CSTM 모형의 경우가 VECM 모형에 비해 모형 적합도가 큰 것으로 나타난다. 둘째, 예측 정확도를 판단하는 지표인 평균 절대 오차와 평균 절대 척도 오차를 살펴보면, CSTM 모형의 오차를 이용한 모형이 VECM 모형의 오차를 이용한 모형보다 총 15가지 경우 중에 12가지 경우에서 예측 정확도가 높은 것을 확인할 수 있다. 미래 연구주제로서 1) 두 가지 오차를 모두 활용하는 분석 및 예측 과제, 2) 원자재 및 에너지 자원 시장의 데이터를 추가하는 과제, 3) 오차항의 부호에 따라 교정계수를 다르게 추정하는 과제 등을 제시한다.