• 임산에너지
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• 제18권2호
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• pp.84-91
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• 1999

The objective of this study was to present creep and the effects of mechano-sorptive deflection of drift pin moment resisting joint between LVL members under changing relative humidity (RH) conditions. The LVL members with steel gusset were jointed by a square pattern of eight injected drift pin. Three diameter drift pins were used to test specimens (6mm, 10mm, and 16mm). The creep test was conducted under two constant loading conditions : one at 30 kgf(840 kgf-cm) and the other at 60 kgf(1680 kgf-cm). The experiment was conducted in an open shed outside. (1)The total rotation creep model of moment resisting joing can be expressed as the sum of the creep of controlled environment (3-parameter model), dimensional change and mechano-sorptive deflection resulting from the variable environment. (2)Mechanosorptive rotation creep is recoverable as moisture content increases during adsorption. Least squares method for linear regression analysis was performed using mechano-sorptive rotation creep as the dependent variable and moisture content as the independent variable. The slope of low moment specimens are compared with those of high moment. This means that low moment condition is more easily affected by changes in humidity than high moment conditions. (3)Although creep deflection is higher for small diameter drift pin than for large diameter drift pin, the shape of creep deflection curves for all specimens is similar.

• 대한기계학회논문집B
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• 제24권5호
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• pp.623-631
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• 2000

Hot-wire measurements were carried out on the developing turbulent flows subject to plane rate of strain in a rotating curved duct. The cross-section of the curved duct varies from 100mm${\times}$50mm rectangular shape at the bend inlet gradually to the 50mm${\times}$100mm rectangular shape at the bend outlet. Experimental setup consists of the test section of $90^{\circ}$ curved duct, rotating disc of 1.95m diameter, Ag-Ni precision slip ring, automatic traversing mechanism, variable speed motor, centrifugal blower, orifice flowmeter and hot-wire anemometer. Data signals from the rotating curved duct are transmitted through the slip ring to the computer which is located at the outside of the rotating disc. 3-dimensional velocity and 6 Reynold stresses components were obtained from the fluctuating and mean voltage measured by the slant type hot-wire probe rotating into 6 orientations. We investigate the effects of Coriolis and centrifugal forces on the turbulence structure.

• 분석과 대안
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• 제7권3호
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• pp.1-26
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• 2023

This article will analyze and forecast important variables and dynamics in global power politics after the war in Ukraine. It tries to use several perspectives to analyze international relations, particularly liberal internationalism and structural realism. In short, core variables are as follows; First, how is the US-led liberal international order and globalization being adjusted? Second, how will the U.S.-China strategic competition, which is the biggest and structural variable, cause changes in the international order in the future? The third variable, how stable are Sino-Russia relations in the context of a structuring U.S.-China-Russia strategic new triangle? Fourth, to what extent will third middle hedging states outside the U.S. and China be able to exercise strategic autonomy in the face of multipolarization? To summarize, the first of these four variables is the largest basic variable at the global political and economic level in terms of its impact on the international community, and it has been led by the United States. The second variable, in terms of actors, seems to be the most influential structural variable in global competition, and the US-China strategic competition is likely to be a long game. Thus the world will not be able to escape the influence of the competition between the two global powers. For South Korea, this second variable is probably the biggest external variable and dilemma. The third variable, the stability of Sino-Russia relations, determines balance of global power in the 21st century. The U.S.-China-Russia strategic new triangle, as seen in the current war in Ukraine, will operate as the greatest power variable in not only global power competition but also changes in the international order. Just as the U.S. is eager for a Sino-Russia fragmentation strategy, such as a Tito-style wedge policy to manage balance of power in the early years of the Cold War, it needs a reverse Kissinger strategy to reset the U.S.-Russia relationship, in order to push for a Sino-Russia splitting in the 21st century. But with the war in Ukraine, it seems that this fragmentation strategy has already been broken. In the context of Northeast Asia, whether or not the stability of Sino-Russia relations depends not only on the United States, but also on the Korean Peninsula. Finally, the fourth variable is a dependent variable that emerged as a result of the interaction of the above three variables, but simultaneously it remains to be seen that this variable is likely to act as the most dynamic and independent variable that can promote multilateralism, multipolarization, and pan-regionalism of the global international community in the future. Taking into account these four variables together, we can make an outlook on the change in the international order.

• 한국산림과학회지
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• 제107권2호
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• pp.184-192
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• 2018

본 연구는 중부지역 일본잎갈나무의 수간중량 추정식을 개발하기 위하여 지역별 개체목의 지위와 직경을 고려하여 표준지를 선정한 뒤, 총 55본의 표본목을 선정하였다. 표본목의 실측자료를 이용하여 수피외생중량, 수피외건중량, 수피내 건중량 및 이용중량 등 네종류의 중량을 추정하기 위해 11개의 모형을 비교 분석하였다. 중량을 추정하기 위해 흉고직경을 변수로 이용하는 경우, 흉고직경과 수고를 이용하는 경우, 재적을 이용하는 경우의 3개 변수에 따라 모형을 구분하였다. 최적의 모형은 적합지수와 추정의 표준오차 및 잔차의 분포를 이용하여 모형의 이행능력을 비교하여 선정하였다. 그 결과, 1변수인 흉고직경을 이용하는 식은 $W=a+bD+c^D^2$이며 설명력은 90~92%를 나타냈고, 흉고직경과 수고를 이용한 2변수식은 $W=aD^bH^C$으로 97~98%의 설명력으로 2변수 모형이 1변수 모형 보다 높은 적합도를 보였다. 또한 전체수간에 대한 재적과 이용재적에 대한 식인 W = aV로 중량추정설명력이 98~99%으로 높게 나타났고 SEE도 7.7~17.5, CV(%)도 8.0~10.0으로 우세한 적합도를 보였다. 본 연구는 개체목의 중량정보 제공 및 임분단위의 중량 바이오매스추정식의 기초연구로 활용될 것으로 판단된다.

• 품질경영학회지
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• 제33권3호
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• pp.126-134
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• 2005

This paper proposes a selectively cumulative sum(S-CUSUM) control chart for detecting shifts in the process mean. The basic idea of the S-CUSUM chart is to accumulate previous samples selectively in order to increase the sensitivity. The S-CUSUM chart employs a threshold limit to determine whether to accumulate previous samples or not. Consecutive samples with control statistics out of the threshold limit are to be accumulated to calculate a standardized control statistic. If the control statistic falls within the threshold limit, only the next sample is to be used. During the whole sampling process, the S-CUSUM chart produces an 'out-of-control' signal either when any control statistic falls outside the control limit or when L -consecutive control statistics fall outside the threshold limit. The number L is a decision variable and is called a 'control length'. A Markov chain approach is employed to describe the S-CUSUM sampling process. Formulae for the steady state probabilities and the Average Run Length(ARL) during an in-control state are derived in closed forms. Some properties useful for designing statistical parameters are also derived and a statistical design procedure for the S-CUSUM chart is proposed. Comparative studies show that the proposed S-CUSUM chart is uniformly superior to the CUSUM chart or the Exponentially Weighted Moving Average(EWMA) chart with respect to the ARL performance.

• 한국항공운항학회지
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• 제23권2호
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• pp.32-39
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• 2015

Airport is not only a public facility but a place where multiple cultural and ethnic groups are visiting. It has been reported though several researches that the level of emotional labor is more heavier than any other job. The more complex our society become, the more frequently emotional labor has been focused. Emotional labor became recently the issue of integrated studies above. Considering the level of emotional labor of airport employees, this paper believes their emotional labor has not been focused compared to such as tourism and service industry. This paper tried to research empirically the impact of internal marketing on airport employees' customer-oriented attitude based on their emotional labor using SEM (Structural Equation Modeling). According to the SEM results, it was proven that 'Autonomy of Airport Employee', a latent variable of internal marketing has a significant negative effect on employees' outside emotion. The outside emotion has also a significant effect on their customer-oriented attitude. It could be concluded the effort to increase decision making authority of employees should be implemented to provide them with deeper customer oriented insight.

• 대한가정학회지
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• 제27권1호
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• pp.85-96
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• 1989

The purpose of study was to survey the indoor noise of apartment houses, residents, attitudes and their adaptation behavior in order to offer the information helpful to apartment designers and residents, in their housing policy. Documentary research and questionnaire survey methods were used in this research. The sample was taken from 187 housewives living in apartments in Seoul. Data were analyzed with the SPSS program. The results were as follow : 1. It was found that apartment residents pointed out washing machine noise inside the home, piano and other musical instruments noise outside the home. 2. Piano and other musical instrument noise were heard at 3 to 6 pp.m. when residents heard the noise, and water supply and drainage noise in bathrooms were found most noisy. 3. Apartment residents were discontent with noise outside the home, and they displayed positive adaptation behavior at a reduced noise level. 4. Attitudes arising from indoor noise in apartment houses and human noise, water supply and drainage noise, doorway opening and closing noise were found to be significant in sampled apartment groups. 5. The youngest child's age was a significant variable on the residents' attitudes and adaptation behavior of indoor noise in apartment houses. 6. Between the resident' attitudes and adaptation behavior involving indoor noise in apartment houses. 6. Between the resident' attitueds and adaptation behavior involving indoor noise apartment houses, the more they became discontented, the more quickly they adapted in a postive manner.

• 한국추진공학회지
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• 제11권5호
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• pp.14-22
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• 2007

측면 표면 기울기가 변화하는 역 사다리꼴 핀이 2차원 해석적 방법을 사용하여 최적화된다. 핀 바닥 경계조건을 위해서, 내부유체로부터 내벽까지의 대류와 내벽부터 핀 바닥까지의 전도가 고려된다. 핀 끝 면으로부터의 열손실은 무시되지 않는다. 실제적인 핀 길이에서의 최대 열손실, 그 최대 열손실이 발생할 때의 최적의 효율, 핀 길이 그리고 핀 바닥 높이가 핀 내 외부의 대류특성계수의 함수로 나타내어진다. 결과 중 하나는 핀 바닥 높이에 대한 핀 끝 높이의 비가 커질수록 최적의 핀 형상은 두껍고 짧아지는 형상이 됨을 보여준다.

• 한국융합학회논문지
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• 제8권11호
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• pp.423-430
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• 2017

이 연구는 보육교사의 행복에 영향을 미치는 생태체계 변인을 분석하고자 하였다. 따라서 이러한 연구목적을 달성하기 위하여 제주도 보육교사를 모집단으로 선정하고, 편의표본추출법을 통해 제주지역 사립 보육교육기관의 보육교사를 대상으로 설문지를 배포하여 분석하였다. 조사에 참여한 보육교사는 총 200명으로 불성실한 응답을 보인 20명의 자료를 제외한 총 180명의 자료를 SPSS 20.0 프로그램으로 분석하여 다음과 같은 결과를 얻을 수 있었다. 연구결과 첫째, 유기체 변인 중 보육교사의 연령과 학력은 보육교사의 행복에 차이를 보였다. 즉 35세 이상의 보육교사는 다른 연령에 비해 행복이 높으며, 대졸 이상의 보육교사도 다른 학력에 비해 행복이 높다는 점이다. 둘째, 미시체계 변인 중 결혼여부만 행복에 영향을 미치는 것으로 나타났다. 즉, 기혼자인 보육교사는 미혼자 보육교사에 비해 행복이 더 높은 것으로 조사되었다. 셋째, 중간체계 변인 중 유아-교사 상호작용이 높을수록, 부모-교사 상호작용이 높을수록 보육교사의 행복수준이 높았다. 넷째, 외체계 변인 중 근무환경과 직무자체 특성이 좋을수록 보육교사의 행복수준이 높은 것으로 나타났다. 따라서 행복한 보육교사에 대한 지속적인 관심과 근무환경 개선, 처우개선 등과 같은 국가적, 행정적 지원으로 현실적인 개선들이 필요할 것으로 판단된다.

• 생물환경조절학회지
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• 제26권4호
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• pp.353-360
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• 2017

본 연구에서는 장미 재배온실을 대상으로 온실 내부의 태양잉여열과 외부의 공기열을 선택적 열원으로 이용하여 온실난방용 온수를 생산할 수 있는 공기 대 물 히트펌프의 설계와 성능시험을 수행하였다. 태양잉여열 이용 축열운전과 외기열 이용 축열운전은 작물의 생육적온을 고려한 온실내부의 설정온도에 따라 자동전환 되도록 설계하였다. 제어반에 12개의 기준온도를 설정함으로써 축열운전 전환, 난방, 환기를 자동제어하며, 태양잉여열-외기열 선택적 축열운전에서 축열조의 온도는 축열능력과 난방부하에 대응하여 $35{\sim}52^{\circ}C$로 3단계 변온제어 하였다. 태양잉여열-외기열 선택적 축열에서 태양잉여열 이용 축열은 전체 시간의 23.1%, 외기열 이용 축열은 30.7%, 히트펌프 휴지시간은 46.2%를 차지하였으며, 난방성능계수는 태양잉여열 이용 축열 시 3.83, 외기열 이용 축열시 2.77, 전체 3.24로 평가되었다. 비교시험을 위해 축열조 온도를 $50{\sim}52^{\circ}C$로 항온제어 하는 조건에서 외기열 단독 이용 축열 시험을 수행하였으며 이때의 난방성능계수는 2.33으로 분석되었다. 결과적으로 공기 대 물 히트 펌프의 열원으로 온실내부 태양잉여열과 외부 공기열을 병용하고, 축열조 온도를 변온제어 한 결과 일반적인 외기열 이용 축열운전과 축열조 항온제어에 비해 난방성능 계수가 39% 향상됨을 확인하였다.