• Earthquakes and Structures
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• 제25권1호
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• pp.69-78
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• 2023

Life-cycle performance analysis of a reinforced concrete box section bridge was generated. Moreover, Monte Carlo simulation with important sampling (IS) was used to simulate the bridge material and load uncertainties. The bridge deterioration model was generated with the basic probabilistic principles and updated according to the measurement data. A genetic algorithm (GA) with the response surface model (RSM) was used to determine the deterioration rate. The importance of health monitoring systems to sustain the bridge to give services economically and reliably and the advantages of fiber-optic sensors for SHM applications were discussed in detail. This study showed that the most effective loss of strength in reinforced concrete box section bridges is corrosion of the reinforcements. Due to reinforcement corrosion, the use of the bridge, which was examined, could not meet the desired strength performance in 25 years, and the need for reinforcement. In addition, it has been determined that long-term health monitoring systems are an essential approach for bridges to provide safe and economical service. Moreover the use of fiber optic sensors has many advantages because of the ability of the sensors to be resistant to environmental conditions and to make sensitive measurements.

• 기본간호학회지
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• 제26권3호
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• pp.197-209
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• 2019

Purpose: This study was done to examine good death awareness, attitudes toward advance directives (ADs), and preference for care near the end-of-life (PCEOL) of hospitalized elders in long-term care hospitals. Relevant characteristics were investigated as well as correlation of the variables. Methods: This descriptive research study involved 161 hospitalized elderly patients in long-term care hospitals. A self-report questionnaire was used to measure Good Death Scale, ADs Survey, PCEOL Scale, and general characteristics. Collected data were analyzed using descriptive statistics, t-test, ANOVA, and Pearson correlation with SPSS/WIN 23.0. Results: In terms of good death awareness, a significant difference was observed; in according to age (F=3.35, p=.037), payer of treatment costs (F=3.98, p=.021), mobility (F=3.97, p=.021), heard discussion about ADs (t=-3.89, p<.001), and willing to complete ADs (t=2.12, p=.036). As far as attitudes toward ADs, the participants presented significant difference depending on religion (t=2.38, p=.018), average monthly income (F=3.91, p=.022), duration of hospital admission (F=5.33, p=.006), person to discuss ADs (t=-2.76, p=.006). On PCEOL, there was a significant difference, depending on religion (t=-3.59, p<.001) and perceived health status (F=3.93, p=.022). Finally, as for how the variables were related to each other, good death awareness and attitudes toward ADs had a weak positive correlation with PCEOL. Conclusion: To help seniors staying in nursing homes face a good death and enjoy autonomy, there should be educational and support systems that reflect each individual's sociodemographic characteristics so that the seniors can choose what kind of care they want to receive near the end-of-life.

• 한국항공우주학회지
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• 제48권8호
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• pp.581-588
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• 2020

고전압 기폭관의 노화 특성에 관하여 연구하였다. 노화 특성 관측을 위해 먼저 고전압 기폭관의 주요 구성품을 분류하고, 고장 메커니즘을 정의하였다. 위력과 감도 측면에서 노화 특성을 정의하였으며, HFC (Heat Flow Calorimetry)를 통해 계산된 활성화 에너지와 아레니우스 이론을 기반으로 가속노화시험 계획을 수립하였다. 노화된 시료를 이용하여 민감도 시험인 Neyer Test와 위력시험인 Dent Test를 통하여 성능 변화를 관측하였다. 민감도 시험을 통해 구한 반폭점에서 노화 경향을 관찰하였으나 관련 규격을 고려하면 충분히 긴 수명을 가지고 있는 것으로 분석되었다.

• 한국군사과학기술학회지
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• 제18권3호
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• pp.267-274
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• 2015

It is necessary to both analyze root-cause of non-conformance of effective illumination time to the specification, and estimate the storage lifetime for 81 mm illuminating projectile stockpiled over 10 years. In this paper, aging mechanism of magnesium flare material due to long-term storage was supposed, and two-stage tests, pre-test and main test based on accelerated degradation tests were performed. Field storage environment of moistureproof was set up, and illumination times in the accelerated degradation tests for temperatures 60 and $70^{\circ}C$ were measured. Then, storage reliability of the projectile was estimated through analyzing the measured data and applying distribution-based degradation models to the data. The $B_{10}$ life by which 10 % of a population of the projectiles will have failed at storage temperature of $25^{\circ}C$ was estimated about 7 years.

• 한국추진공학회지
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• 제23권1호
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• pp.9-14
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• 2019

고체 추진기관의 HTPB 추진제는 저장소에서 저장소 환경에 따라 물리적, 화학적 노화가 진행된다. 추진기관 수명은 HTPB 추진제의 노화도에 의해 결정되며, 생산 초기에 점탄성 특성 및 노화 시험을 통해 예측된다. 본 논문에서는 생산 초기 물성 및 가속노화 시험을 통해 획득한 노화 물성과 장기 저장되어 자연 노화된 물성을 비교 분석하였다. 획득된 초기 및 노화물성 결과를 적용하여 중공형 그레인의 온도 하중에 의한 변형율을 분석하였다.

• 한국가스학회지
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• 제27권2호
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• pp.71-78
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• 2023

일반적으로 평균 수명이 1.0~1.5년인 전기식 액중형 펌프(electrical submersible pump, ESP)는 유·가스 및 저류층 특성, 운영 조건에 따라 성능 저하 및 수명 감소가 발생하며, 이에 따른 ESP의 고장은 회수 및 설치에 따른 높은 유정 개·보수(workover) 비용과 생산 중단에 따른 추가 비용이 발생한다. 이에 본 연구에서는 유·가스정에서 ESP 장기 운영에 따른 수명을 예측하고자 환형 유동 시스템(flow loop system)을 설계 및 구축하고, ESP 설치 초기 시점부터 고장 시점까지의 ESP 수명에 대한 전 주기 데이터를 취득 및 분석하였다. 구축한 시스템에서 산출되는 데이터 중 ESP의 유체유량, 흡입구 및 토출구의 온도, 압력 그리고 외측부에 설치된 진동 측정기의 데이터 분석을 통하여 ESP 장기 운영에 따른 성능 상태를 정상(normal), 권고 I (advise I), 권고 II (advise II), 유지관리(maintenance), 고장(failed)의 총 5단계로 분류하였다. 실험 결과를 통해 ESP 장기 운영시 단계별 데이터의 경향 차이를 확인하였으며, 이를 통해 운영 기간에 따른 ESP의 상태를 진단하고 펌프의 고장을 예측하였다. 본 연구를 통해 도출된 결과는 유·가스정에서 운영되는 ESP의 상태 모니터링(monitoring) 을 위한 고장 예측 프로그램 및 데이터 분석 알고리즘 개발에 활용될 수 있을 것으로 판단된다.

• 대한간호학회지
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• 제13권2호
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• pp.58-69
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• 1983

This study on stressful life events and coping methods of hypertensive and nonhypertensive patients was applied to people who was divided into two groups from April 5 to March 10, 19 83. One is hospitalized patients in medical wards of three university hospital in Seoul. The other is inhibitants in two Dongs of Seoul. This study compared the number and seversity of stressful life events reported by hypertensive and nonhypertensive patients, indentified coping methods used by the two groups and explored the relationship between stressful life events and coping methods. Two instruments are used in this study. The first one to measure stressful life events, is Holmes ＆ Rahe (1967)'s S.R.R.S. (Social Readjustment Rating Scale). Which is translated & am-ended. So that it consists of 46 items. The second one is for evaluating coping method. It consists of f items amended through preliminary test after consideration of related literature review and survey on the basis of Bell (1977)'s‘18-item-Questionnaire.’The materials were analyzed by S.P.S.S. (Statistical Package for the Social Science) program-The results of analysis were as follows: 1. There were no significant difference in the number and severity of stressful life events reported by hypertensive and nonhypertensive patients (p>.05). 2. There were significant difference in use of short-term coping methods (p<.01) and long-term coping methods (p<.05).

• 치위생과학회지
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• 제14권3호
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• pp.379-389
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• 2014

요양병원에서 6개월 이상 입원 가료중인 노인환자들을 대상으로 구강건강상태를 객관적으로 평가하였고, 전신질환 및 우울감 상태를 파악하여 구강건강관련 삶의 질과의 관련요인을 확인한 결과는 다음과 같다. 대상자의 잔존치아 수는 11.22개였고, 우식치아 수는 1.17개, 동요치아 수는 0.93개였으며, 81.9%에서 구취가 확인되었다. 전신질환이 없거나 한 가지 미만인 경우는 29.70%에 불과하였고, 70.31%가 두 개 이상의 복합적인 전신질환을 가지고 있었다. 대상자의 87.8%에서 우울감이 있었으며, 이 중 55.40% 는 심한 우울감을 나타냈다. 구강건강관련 삶의 질은 평균 2.62점이었고, 관련요인으로는 요양등급, 입원기간, 연령과 함께 잔존치아 수와 우식치아 수로 확인되었다. 이상의 결과를 통해 요양병원에 장기입원 중인 노인환자는 일반노인에 비해 전반적으로 구강건강상태가 좋지 않았으며, 전신질환 수와 우울감이 높고, 구강건강관련 삶의 질이 낮아 고령화사회에서 노인인구를 위한 대책이 시급하며, 특히 요양시설 노인환자를 위한 구강건강관리 프로그램 개발이 필요할 것으로 생각된다.

• 가정과삶의질연구
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• 제11권1호
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• pp.107-118
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• 1993

A dimension of well-being economic security was analyzed and compared with economic adequacy. Again it was tested whether two indicators of economic security(short-term vs. long-term) yield same distribution across all household groups. Economic Security was defined as the household ability to sustain a given level of consumption in the case of economic emergency; specifically loss of income. Measure of 8 different kinds of economic security were constructed from household net worth including and excluding home equity. Data were taken from the 1988 U.S. Consumer Expenditure Survey and 2148 households were selected to test hypotheses concerning the economic security of American households Empirical results showed a very low level of economic security in general. The first hypothesis that distribution of economic adequacy and economic security are same across all population groups was rejected. On the average security measure rather than adequacy measure was favor to white female-headed households and households who have old and highly educated house-holder. The second hypothesis that the indicators of long-term and short-term economic security yield the same results across all household was not rejected. In general the level of economic security was relatively higher when long-term indicator was used than short-term indicator was however the direction and relative size of effect of income and each control variable was almost same.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.157-159
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• 2002

In order to obtain reliability and extend life of GAS Voltage Transformer in GIS, it has to prevent aging by overvoltage considered to insulation characteristics of insulating material. This paper describes some characteristics of V-T characteristics and partial discharges.