• 한국연소학회지
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• 제5권2호
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• pp.63-68
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• 2000

Combustion phenomenon in scale-downed combustor is investigated. As the combustor scale decreases surface to volume ratio increases and chamber size approaches quenching distance. As the combustor scales down surface to volume ratio increases resulting increased heat loss. And this heat loss can affect quenching and instability of the flame. To investigate this effect plastic mini combustor is made. Stoichiometricaly premixed Hydrogen / air gas is used as fuel. Initial chamber pressure and chamber size are varied and the effects are evaluated. Peak pressure decreased with the decrease in chamber height. As initial chamber pressure decreases peak pressure decreases and this change is more important than scale down effect till the chamber height of 1mm. With this result and further information following the experiments design parameter for micro engine can be established.

• Journal of Korea Trade
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• 제23권7호
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• pp.13-33
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• 2019

Purpose - This study empirically investigated whether national distances (Cultural, Administrative, Geographic and Economic distance) have different effects on industries in different ways. Design/methodology - The empirical model utilized industry level export trade data to examine the differentiated effects of each national distance. By using direct measurement and covering 75 countries, this paper analyzes the effect of distances in different industries. More specifically, this study classified the industries into a more-sensitive/less-sensitive scale. Findings - The empirical results showed the complicated impacts of national distances on trade. Trade in industries that are more sensitive to cultural and administrative distances was not decreased as greatly as trade in industries that are less sensitive to cultural and administrative distances. Also, industries that are more sensitive to geographic distance showed a stronger negative impact on trade than less sensitive industries. Lastly, economic distance decreased trade for industries that are more sensitive to economic distance, while economic distance did not significantly increase trade for industries that are less sensitive to economic distance. Originality/value - As the first study to empirically find out whether national distance has different effects on industries, this study updated the measurements of national distance.

• 지역사회간호학회지
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• 제30권4호
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• pp.539-549
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• 2019

Purpose: The aim of this study was to identify the factors related to the social distance toward older adults in nursing college students. Methods: The participants comprised 137 students in a nursing college. Data were collected using self-report questionnaires in March 2019. The measurement instruments included social distance scales, the Fact on Aging Quiz (FAQ I), a 20-item semantic differential scale (to assess attitudes), and the perceived elderly stigma scale. The data were analyzed using descriptive statistics, independent t-tests, one-way analysis of variance (ANOVA), Pearson's correlation coefficient, and a multiple regression analysis. Results: The total score for social distance toward older adults was 3.98±0.54 out of a maximum of 5. Social distance had a statistically significant relationship with knowledge (r=.20, p=.022), attitudes toward older adults (r=-.31, p<.001), and elderly stigma (r=-.27 p=.008). The factors affecting social distance were education in geriatrics (β=.33, p=.004), grade (β=-.29, p=.014), attitudes (β=-.21, p=.018), academic major satisfaction (β=.19, p=.028), and knowledge (β=.15, p=.048); the explanatory power of the model was 34%. Conclusion: There is a need for departmental efforts that nursing students acquire correct knowledge about the life and health of the elderly with the aging process and develop positive attitudes toward older adults through various experiences in gerontological nursing practicum and community senior-college student link programs.

• 대한전자공학회논문지SP
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• 제38권1호
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• pp.1-10
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• 2001

디지털 프린터와 같은 이진 출력 장치에서 영상을 표현하기 위해서는 연속 계조 영상을 이진 영상으로 변환하는 해프토닝 기법이 요구된다. 본 논문에서는 이진화 된 영상에서 균일한 도트들의 분포를 얻기 위하여 새로운 오차확산 방법을 제안한다. 제안하는 방법에서는 먼저, 현재 이진화 하려는 화소와 이미 이진화 된 소수화소(minor pixel)들간의 최소거리를 '최소화소거리(minimum pixel distance)'라 정의한다. 또한, 오차확산방법에의 적용을 위하여 계조값을 새로운 주거리 기반의 변수로 변환한다. 기존의 오차확산 방법에서는 이진화에 따르는 계조값의 차이를 주위 화소들에 전파하는데 반하여 제안하는 방법에서는 주거리상의 차이가 전파된다. 이진화 과정에서는 최소화소거리가 문턱치로 사용된다. 본 논문에서는 최소화소거리를 계산하는 방법으로 'MPOA'(Minor Pixel Offset Array)를 제안한다. MPOA는 이미 이진화 된 영역의 이진 화소의 종류와 2차원상의 위치를 1차원으로 표현하는 기법으로서 최소화소거리의 계산에 필요한 메모리와 계산량을 크게 감소시킨다.

• 한국환경복원기술학회지
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• 제10권4호
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• pp.31-40
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• 2007

Recently, the scale in the field of reinforced soil retaining wall has been grown up like tiered reinforced soil retaining wall. However, there have been increasing number of collapse accidents and large scale of collapse. The design manual adopted in the construction fields have been inconsistent in tiered reinforced soil retaining wall. Therefore, this study performed finite element analysis on 90 cases and analyzed characteristic behavior of lower wall which was one of the effect factors on the stability of tiered reinforced soil retaining wall. The facing displacement of each walls and the behavior of the whole ground were interpreted by the numerical analysis depending on the lower offset distance by the upper wall as well as the upper offset distance by the surcharge load. The results showed that the behavior of tiered reinforced soil retaining wall was differed by condition of surcharge load and each offset distance was found to be important factor.

• 한국농촌건축학회논문집
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• 제8권1호
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• pp.62-69
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• 2006

This study is based on the ecological design method related with the Building Landscape in Coastal Area, basically Building Landscape design theories are affected the visual distance and visual area. The results derived of this study are as follows. First, We established design method of Building Landscape in Coastal Area in consideration of Ecological Environment that is purposed by means of the Normative theory study analysis and contents analysis related with Landscape and Architecture planning theory. Second, We can define 'Micro Landscape', 'Urban Landscape', and 'Wide Landscape'. 'Micro Landscape' are 'Near view'. 'Urban Landscape' are related 'Middle-distance view' and 'Long-distance view'. 'Wide Landscape' are related 'High & Long-distance view'. Third, We can also define 'Ecological Mode', 'Formal Aesthetic Mode', 'Psychological Mode', and 'Semiotical Mode' by the dimensions of macro scale. finally, we define 48 detailed factors types of 3 visual Area of Building Landscape in Coastal Area by the dimensions of micro scale.

• 한국터널지하공간학회 논문집
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• 제7권4호
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• pp.295-304
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• 2005

지하철의 터널구간에서 화재가 발생하였을 때의 연기전파거리를 측정하였다. 대상은 길이 800m, 단면 $8{\times}5.5m$의 전형적인 지하철 터널로 3개의 급배기 겸용 샤프트가 설치되어 있으며 실험은 1/50의 축소모형을 이용하였다. 연기전파거리 측정을 위하여 열전대와 가시화 기법을 동시에 사용하여 정확도를 확보하였다. 급배기량과 화재크기가 연기전파거리에 미치는 영향을 파악하기 위하여 9개의 조건을 대상으로 실험하였다. 실험결과 분석을 통하여 지하철터널의 배연 설계에 있어서 연기전파거리가 주요 설계요소가 될 수 있음을 밝혔다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.150-151
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• 2022

Blasting is a method that uses explosives to crush the ground. This method is a highly efficient ground cleaning method that can secure high efficiency in a short time. However, explosions can damage local properties and produce high noise and vibration. Therefore, it is important to be careful because there are disadvantages such as the occurrence of many complaints from the surrounding area. In this paper measured and analyzed the noise and vibration generated during blasting at the blasting site in Korea. The noise and vibration generated during blasting were measured by ES03303.2b and ES03402.2a at a distance of 6 m, 12 m from the blasting point. As a result of the measurement, there was little difference between small and medium scale except for precision vibration blasting at a distance of 6m, but noise difference according to blasting scale was evident at a distance of 12m. As a result of the measurement, the maximum noise level was reduced to 5.5 dB(A) and the vibration level was reduced to 7.7 dB(V). In the future, the reliability of the test results can be further improved through additional tests, and it is judged that noise and vibration prediction models based on blasting methods, amount of charge, measuring distance, etc. can be developed.

• KIEAE Journal
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• 제14권4호
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• pp.119-125
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• 2014

This study investigated the effects of pipe network materials and distance on system performance utilizing unused energy sources in large-scale horticulture facility. For this, the modeling was performed with a 100 m long and 100 m wide rectangular shaped glass house having an area of 1ha ($10,000m^2$) using EnergyPlus software. The heat sources considered were air source, geothermal heat, power plant waste heat, sea water heat, and river water. The temperature variation of the fluid with regard to pipe material and distance from the heat source and the resultant heat pump electricity consumptions were calculated. It turned out that the fluid temperature reaching the heat pump increased as the distance from the heat source increased in case of sea water and river water, which have higher temperatures than the surrounding soil, improving the heat pump efficiency. It was vice versa in case of the power plant waste heat. In addition, pipe material of PVC showed the smallest effect on the system performance variation due to the lowest thermal conductivity, compared to PB and HDPE.

• 대한기계학회논문집B
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• 제39권8호
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• pp.703-711
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• 2015

작업의 효율을 높이기 위해서 대형 공장에서 개구부는 주로 개방 되어 있다. 그러나 동절기에 공장에서 난방을 하는 경우 개방되어 있는 개구부는 난방부하를 상승시키는 큰 요인이다. 때문에 공장에서는 개구부 상단에 에어커튼을 설치하여 외부의 침기를 막아 난방부하를 낮춘다. 일반적인 에어커튼의 설계 변수로는 토출 각도와, 속도, 온도 등이 존재하며 이에 대한 연구는 이미 많이 진행되었다. 하지만, 공장이라는 공간적 특수성을 고려하였을 때, 기존에 연구되지 않은 개구부로부터의 이격 거리와 토출구 폭에 대한 부분도 차단 성능에 영향을 미친다. 그 결과 에어커튼은 이격 거리가 가깝고, 토출구 폭은 넓을수록 차단 성능이 좋았다. 이격 거리가 존재하더라도 토출구 폭을 증가시키면 차단 성능이 향상되었으며, 토출구 폭을 증가시킴으로써 약 13.7%의 차단 성능의 향상을 기대할 수 있다.