• 한국환경복원기술학회지
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• 제23권5호
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• pp.1-14
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• 2020

In order to improve the urban thermal environment, efforts are being made to increase green areas in cities that include park construction, planting, and green roofing. Among these efforts, urban parks play an important role not only in improving the urban thermal environment, but also in terms of ecosystem services (serving as resting places for citizens, providing cleaner air quality, reducing noise, etc.). Therefore, the purpose of this study is to suggest planning and management guidelines for urban parks that are effective in improving the thermal environment, by analyzing the urban surface temperature reduction performance of urban parks. To do this, first, land surface temperature was calculated by using Landsat 8 images. Second, the PCI (Park Cool Island) index was calculated to identify the temperature reduction performance of urban parks. Third, the characteristics of parks (area, shape, vegetation) and the surrounding spatial characteristics (land cover, building-related variables, etc.) were identified. Finally, the relationship between the PCI indices (PCI scale, PCI effect, PCI intensity) and the characteristics of the parks and their surroundings were analyzed. The results revealed that the parks consisting of a larger area, simple shape, and higher tree coverage ratio had increased PCI performance, and were advantageous for improving the urban thermal environment. Meanwhile, PCI performance was found to have decreased in areas with a higher impermeable area ratio and building coverage ratio. The outcomes of this study can be used to identify priority areas for planning and management of urban parks and can also be utilized as planning and management guidelines for improving urban thermal environment.

• 대한기계학회논문집B
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• 제41권6호
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• pp.397-407
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• 2017

본 논문에서는 연비손실 없이 높은 $NO_X$ 저감성능을 보이는 승용 디젤 엔진의 SCR 시스템을 위한 요소수의 분사전략을 제시하였다. 배출되는 $NO_X$량 대비 요소수가 화학량론적 1:1인 피드포워드 분사 전략과 함께 모델기반의 촉매 내 $NH_3$ 흡장률 추정 기법을 통하여 피드백 분사 제어전략을 함께 사용함으로써 과도상태에서 $NO_X$ 저감성능과 $NH_3$ 슬립 성능을 모두 만족시키고자 하였다. 제안된 분사전략을 적용하여 디젤산화촉매기와, 미립자필터가 장착된 2.2L 디젤 엔진을 갖춘 실제 차량에서의 실험을 통하여 제어기의 높은 $NO_X$ 저감률과 낮은 $NH_3$ 슬립 성능을 검증하였다.

• 한국환경복원기술학회지
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• 제18권2호
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• pp.45-52
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• 2015

Cool-season turfgrass is a rapidly increasing of usage for the revegetation of waterside slopes in dams, lakes and rivers. The purpose of this research is to identify the flooding tolerance of cool-season turfgrass with respect to the flooding periods of 0(control), 2, 4 and 6 days, respectively. The surface coverage ratio, turfgrass injury and soil moisture content were measured to assess the flooding tolerance of cool-season turfgrass. The increase in the flooding periods with 4 and 6 days resulted in the lower surface coverage ratio for cool-season turfgrass while no significant difference was found in the 2 days flooding when compared to 0 day (the control plot) flooding plot. In case of the turfgrass injury and the soil moisture content, however, the higher values were found with the increase of flooding periods in 2, 4 to 6 days. We observed that the higher the turfgrass injury and soil moisture content increased, the lower the surface covrage ratio decreased. In these regards, we also observed that the tolerance of cool season turfgrass were high in the 2 days flooding condition, medium in the 4 days flooding condition and low in the 6 days flooding condition. The flooding tolerance of cool-season turfgrass was gradually weakened in over 2 days flooding periods due to $O_2$ deficiency in the anaerobic soil condition. Therefore, we could suggest cool-season turfgrass within 2 days flooding periods for the revegetation of waterside slopes in dams, lakes and rivers.

• 한국환경복원기술학회지
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• 제5권6호
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• pp.72-85
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• 2002

This study was conducted to investigate the germination rates and ground coverage rates of the 16 native wild flower, herbaceous, shrub and woody plants according to temperature and seeding timing for the revegetation and rehabilitation of the roadside slopes. Also, this study was conducted to suggest design criteria to select revegetation plants and to decide proper seed mixture for ecological restoration of the disturbed manmade slopes as a environmentally friendly construction. The results are summarized as follows. 1. Most of the plants germinated after 10~14 days. Woody plants germinated more slowly than wild flowers and herbaceous plants because of the hard seed. 2. Most of the plants showed the highest percentage of the germination rates under $15/25^{\circ}C$ temperature. The next was in order of under the $20/30^{\circ}C$ temperature, normal temperature(October) and $25/35^{\circ}C$ temperature. 3. At the chamber experiment, the Sorbaria sorbifolia var. stellipila showed the highest germination rates. Most of the native wild flowers germinated well and showed high germination rates under the various temperature. 4. As the field germination experiments, the seeding at August shows higher germination rates than that of the seeding at September, but showed lower surviving percentage of the germinated seedlings and lower ground coverage percentage than those of the seeding at September. After one year, Chionanthus retusus, Acer palmatum, Albizzia julibrissin are germinated and showed 10% coverage rates. So, they can be used as revegetation plants for the restoration works. 5. As seed mixture experiment, it was not effective only to increase the proportion of the ratio of the tree seeds, relatively high price, for making woody vegetation. It would be more successful to make vegetation structure by natural competition among wild flowers, shrubs and trees. 6. The excessive dominance of trees in revegetation works may destroy the lower layer of vegetation and it will be undesirable on the species diversity. It is more important to recover the species diversity of the plant community by seed mixture with the considering the germination, the growth characteristics and the correlation effect among revegetation plants. 7. To recover the manmade slopes quickly, increasing the ratio of the wild flower was recommended.

• 한국토양비료학회지
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• 제40권3호
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• pp.208-213
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• 2007

1985년부터 1991년까지 일 강우량 80 mm 이상일 때의 유거량 자료를 이용하여 집중강우시 물유출 양상을 구명하였다. 지표유거가 발생하는 유거 발생 최소 강우량은 지표피복과 경사장에 따라 결정되는 것으로 나타났으며 토성과 경사각에 따라서는 별 차이를 나타내지 않았다. 유거 발생 최소 강우량을 기준으로 그 이후의 유거량은 강우량에 따라 직선적으로 증가하였다. 그러나 이 때의 기울기 즉, 유거율은 토성, 지표 피복형태, 경사각, 경사장에 따라 달라졌다. 유거율은 토성이 세립질로 침투속도가느릴 수록 커졌으며 콩 재배에 비해 물흐름에 대한 저항이 작은 나지에서 컸다. 또한 유거율은 경사각의 제곱근에 비례하여 증가하였으며 경사장이 길어짐에 따라 특정값에 수렴하면서 감소하였다. 이러한 결과를 바탕으로 집중강우 시 유거량을 모사할 수 있는 식을 다음과 같이 개발하였다. $$Runoff=a(s^{0.5}+l^b)(Rainfall-80(1-e^{-bl}))------(9)$$ 이 식에서 a는 토양의 침투특성과 관련된 토양계수, b는 지표 피복의 영향을 나타내는 지표피복계수, s는 경사각(radian), l은 경사장(m)이다. a는 토성에 따라 0.5~0.6으로 나타났으며 세립질일 수록 값이 컸다. b는 피복조건에 따라 나지에서 0.06, 콩 재배시 0.5 정도로 평가되었다.

• Journal of Preventive Medicine and Public Health
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• 제27권1호
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• pp.117-134
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• 1994

대구직할시 남구 1 개동 주민을 대상으로 도시 지역의료보험 실시 전후(이하 실시 전후)의 의료 이용양상을 파악하기 위하여 실시 6개월 전인 1989년 1월에 1차조사를 하였고, 실시 1년 6개월 후인 1991년 1월에 2차조사를 하였다. 1차조사의 대상자는 1,230가구 4,939명이 었으나, 2차추적조사가 가능했던 인구는 519가구 2,277명 (추적률:46.1%)이었다. 2차조사까지 추적이 가능했던 2,277명 중 1차 조사시 보험에 가입되지 않았던 240가구 1,033명을 코호트 I군(이하 I군)으로 하였고, 1차조사시 보험에 가입되었던 279가구 1,244명을 코흐트 II군(이하 II군)으로 구분하여 조사자료를 분석하였다. 인구 1,000명당 급성이환으로 인한 의사방문율의 변화는 실시 후에 I군에서 16.5 증가한 반면, II에서는 2.4만 증가하였으며, 만성이환에서도 I군이 13.5 증가하였으나 II군은 7.2만 증가하였다. 이환 및 활동제한 의료필요 충족률도 I군에서 실시 후 뚜렷히 증가하였다. 월가구소득별 급성이환에 의한 의료필요충족률은 I군에서 40만원미만군이 1.6으로 $40{\sim}99$만원군의 4.0과 100만원이상군의 49.3에 비해 월등히 낮았다. 이러한 소견은 나머지 조사대상군과 만성이환에서도 동일하였다. 급성과 만성이환자의 병원이용 이유는 유용성, 의원의 경우는 지리적 접근성이 실시전후모두에서 가장 많았고 약국이용 이유 중 실시 전에는 접근성과 의료비지불성이 중요하였으나, 실시 후에는 의료비지불성의 중요성은 상대적으로 감소하였다. 최근 15일간 의사방문여부를 종속변수로한 multiple logistic regression analysis에서 급성이환(+), 만성이환(+) 그리고 월가구소득(+)이 실시전후 모두에서 유의한 변수였다. 실시 후 부과된 보험료에 대한 불만족률이 두군 모두 지역의료보험 가입자에서 각각 81.0%와 74.1%로 타 의료보험가입자에 비해 월등히 높았다. 실시 후 병원과 의원의 의료비와 서어비스에 불만족스럽다고 응답한 사람이 I군에 비해 II군에서 더 많았다. 이상의 소견으로 의료보험이 실시됨으로 미충족의료수요를 감소시키는 효과를 가져왔으나 실시 후에도 저소득층의 의료이용률이 고소득층에 비해 여전히 낮아 의료보험실시로 경제적 장애가 감소하였음에도 불구하고 본인부담금 등으로 인한 경제적 장애와 의료기관을 방문하는데 소요되는 시간, 대기시간 등 의료이용을 저해하는 요인이 남아있어 의료이용의 형평이 사회계층들간에 완전히 이루어지지는 않았다. 특히 만성이환의 경우, 불균형이 심하였다. 또한, 부과된보험료에 대한 불만족도가 높아 현행 보험료선정기준의 재평가 및 공정성을 향상시킬 필요성이 제기되었다.

• Journal of the Korean Data and Information Science Society
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• 제13권2호
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• pp.201-207
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• 2002

In this paper, Jeffrey's and reference priors are derived when the parameter of interest is the ratio of means of two in dependent Poisson distribution. To achieve the parameter orthogonality in the sense of Cox and Reid (1987), non-trivial orthogonal transformation is provided. The orthogonal transformation makes to find noninformative priors easy. Our simulation study indicates that the reference prior meet very well the target coverage probabilities in a frequentist sense. Using the real data, we compute Bayes estimator and MLE for the ratio of means based on the reference prior.

• Communications for Statistical Applications and Methods
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• 제14권3호
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• pp.633-640
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• 2007

We develop noninformative priors for the ratio of the lognormal means in equal variances case. The Jeffreys' prior and reference priors are derived. We find a first order matching prior and a second order matching prior. It turns out that Jeffreys' prior and all of the reference priors are first order matching priors and in particular, one-at-a-time reference prior is a second order matching prior. One-at-a-time reference prior meets very well the target coverage probabilities. We consider the bioequivalence problem. We calculate the posterior probabilities of the hypotheses and Bayes factors under Jeffreys' prior, reference prior and matching prior using a real-life example.

• 산업경영시스템학회지
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• 제30권2호
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• pp.37-43
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• 2007

ANOVA is widely used for measurement system analysis. It assumes that the measurement error is normally distributed, which may not be seen in certain industrial cases. In this study, the exact and bootstrap confidence intervals for precision-to-tolerance ratio (PTR) are obtained for the cases where the measurement errors are normally and non-normally distributed and the reproducibility variation can be ignored. Lognormal and gamma distributions are considered for non-normal measurement errors. It is assumed that the quality characteristics have the same distributions of the measurement errors. Three different bootstrap methods of SB (Standard Bootstrap), PB (Percentile Bootstrap), and BCPB (Biased-Corrected Percentile Bootstrap) are used to obtain bootstrap confidence intervals for PTR. Based on a coverage proportion of PTR, a comparative study of exact and bootstrap methods is performed. Simulation results show that, for non-normal measurement error cases, the bootstrap methods of SB and BCPB are superior to the exact one.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.975-976
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• 2006

The present paper is a parameter study of zinc flake production using a Simoloyer CM01 horizontal high energy rotary ball mill. The manufactured flakes have a dimension in thickness (t) < $1{\mu}m$ and diameters (d) 5-100 ${\mu}m$, consequently a ratio d/t up to 200. The flake geometry is mainly controlled by the variation of process parameters such as rotary speed of the rotor, ratio of powder/ball charge, load ratio of the system, process temperature, operating model and the quantity of process control agent (PCA). The Zn flakes were characterized by SEM, tap densitometry, laser diffraction and water coverage measurement.