• 한국환경복원기술학회지
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• 제18권3호
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• pp.65-77
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• 2015

The urban park has important functions as a habitat for wildlife as well as open space of rest and community for people. This study was carried out to find what factors of structure and vegetation of urban parks could affect forest bird species diversity in Cheonan city. The study surveyed bird and vegetation species in 26 urban parks, Cheonan city. A correlation analysis and multiple linear regressions were performed to test whether habitat structure and vegetation were the major correlate with species diversity. The results showed the Dujeong park was the most high bird species diversity (H' = 2.13), and the Dujeong-8 park (H' = 2.02) and the Cheongsa park (H' = 1.73) were considerably higher than the other urban parks. The variables that were strongly correlated with bird species diversity were park area, number of subtree species, canopy of shrub, number of shrub species, shape index, canopy of subtree, canopy of tree, and impervious surface ratio. The regression of bird species diversity against the environmental variables showed that 3 variables of park area, canopy of subtree, and canopy of tree were included in the best model. Model variable selection was broadly similar for the 5 optimal models. It means park area and multi-layer vegetation were the most consistent and significant predictor of bird species diversity, because urban parks were isolated by built-up areas. Especially the subtree coverage that provides shelter and food for forest birds was an important variable. Therefore, to make parks circular-shaped and abundant multi-layer vegetation, which could be a buffer to external disturbances and improve the quality of habitats, may be used to enhance species diversity in creation and management of urban parks.

• 대한의용생체공학회:의공학회지
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• 제31권5호
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• pp.375-384
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• 2010

The purpose of this study is to determine whether there is a correlation between the segmental bio-impedance measurement with the frequency modulations and the life-style disease of obesity. An obesity is not simply the factor for estimating the life-style disease of obesity, but also the risk factor occurring. There are many methods (BMI, WHR, Waist, CT, DEXA, BIA, etc.) for measuring a degree of obesity; the bio-impedance measurement is more economic and more effective than others. The physical examination, the blood test, the medical imaging diagnosis and the bio-impedancemeasurementswithmultiple frequencies for each body parts have been conducted for 77 people. The estimated value has been calculated through a segmental bio-impedance model based on multi-frequency that was created to reflect the highest correlation by analyzing correlation with linear regression analysis method for the measured bio-impedance and the risk factors. Then we compared with the clinical diagnosis. In case of high level cholesterol, low HDL-C and high LDL-C for life-style disease, the sensitivity is 80~100%and the specificity is 83~100%. This study has shown conclusively that bio-impedance can be a possible predictor to analyze the disease risk rate of population and individual health maintenance. And also the multi-frequency segmental bio-impedance can be used as early predictor to estimate the life-style disease of obesity.

• 한국지구과학회지
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• 제38권4호
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• pp.283-292
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• 2017

본 연구에서는 서울지역의 지상 미세먼지($PM_{2.5}$) 농도를 산출하기 위하여 경험적인 모델들을 개발하였다. 연구에 이용한 자료는 2012년 1월 1일부터 2013년 12월 31일까지이며 Terra와 Aqua위성의 MODIS센서에서 산출되는 에어로졸 광학두께, 옹스트롬 지수, 기상변수들과 행성경계층두께와 관련된 6개의 다중 선형 회귀모델들의 차이를 분석하였다. 그 결과 에어로졸 광학두께와 옹스트롬 지수, 상대습도, 풍속, 풍향, 행성경계층두께, 기온 자료를 입력 자료로 사용한 $M_6$모델이 가장 좋은 결과를 보였다. 통계적인 분석에 따르면 $M_6$ 모델을 사용하여 계산된 $PM_{2.5}$와 관측된 $PM_{2.5}$농도 사이의 결과는 상관계수(R=0.62)와 평균제곱근오차($RMSE=10.70{\mu}gm^{-3}$)이다. 또한 산출된 계절별 지표면 $PM_{2.5}$농도는 여름철(R=0.38)과 겨울철(R=0.56)보다 봄(R=0.66)과 가을철(R=0.75)에 상대적으로 더 좋은 상관 관계를 보였다. 이러한 결과는 에어로졸 광학두께의 계절별 관측 특성으로 인한 것으로써 다른 계절에 비하여 여름과 겨울철 에어로졸 광학두께 관측이 구름과 눈/얼음 표면에 의한 관측 제한과 오차를 가져온 것으로 분석되었다. 따라서 본 연구에서 사용한 경험적 다중선형회귀 모델은 위성에서 산출된 에어로졸 광학두께 자료가 지배적인 변수로 작용하며 $PM_{2.5}$산출 결과들을 향상시키기 위해서는 추가적인 기상 변수를 이용해야 할 것이다. 또한 경험적 다중선형회귀 모델을 이용하여 $PM_{2.5}$를 산출한 결과는 인공위성 자료로부터 대기환경 감시를 가능하게 하는 방법이 될 수 있어 유용할 것이다.

• Journal of Korean Neurosurgical Society
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• 제57권6호
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• pp.455-459
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• 2015

Objective : A cost comparison of the surgical clipping and endovascular coiling of unruptured intracranial aneurysms (UIAs), and the identification of the principal cost determinants of these treatments. Methods : This study conducted a retrospective review of data from a series of patients who underwent surgical clipping or endovascular coiling of UIAs between January 2011 and May 2014. The medical records, radiological data, and hospital cost data were all examined. Results : When comparing the total hospital costs for surgical clipping of a single UIA (n=188) and endovascular coiling of a single UIA (n=188), surgical treatment [$mean{\pm}$standard deviation (SD) : \$8,280,000{\pm}1,490,000$] resulted in significantly lower total hospital costs than endovascular treatment ($mean{\pm}SD$ : \$11,700,000{\pm}3,050,000$, p<0.001). In a multi regression analysis, the factors significantly associated with the total hospital costs for endovascular treatment were the aneurysm diameter (p<0.001) and patient age (p=0.014). For the endovascular group, a Pearson correlation analysis revealed a strong positive correlation (r=0.77) between the aneurysm diameter and the total hospital costs, while a simple linear regression provided the equation, y (\)=6,658,630+855,250x (mm), where y represents the total hospital costs and x is the aneurysm diameter. Conclusion : In South Korea, the total hospital costs for the surgical clipping of UIAs were found to be lower than those for endovascular coiling when the surgical results were favorable without significant complications. Plus, a strong positive correlation was noted between an increase in the aneurysm diameter and a dramatic increase in the costs of endovascular coiling.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.81-89
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• 2021

This study aimed to investigate the factors affecting Logistics capabilities for Logistics Service Providers in Vietnam. Researchers inherited and developed based on previous research to focus on analyzing and evaluating dynamics, measuring Logistics capabilities, and the factors affecting Logistics capabilities for Logistics Service Providers. The logistics capabilities Model is used based on three factors: customer demand management capability, innovation capability, and information management capability. The empirical analysis used data from the survey data of l90 managers of Logistics Service Providers in Hai Phong, Ho Chi Minh City, Da Nang, Hue, Hanoi with reliable tools (SPSS 26.0 software). The data were analyzed by frequencies, percentages, means, Pearson's Linear Correlation Coefficient, exploratory factor analysis, and multi-linear regression model based on the survey data. The research results identified the following factors affecting Logistics capabilities for Logistics Service Providers: innovation capability has the strongest impact on Logistics capabilities; customer demand management capability has the following strong effects on Logistics capabilities; and finally, information management capability that affects Logistics capabilities. There is also a positive relationship between all factors and Logistics capabilities. Several recommendations are further suggested to enhance to improve Logistics capabilities for Logistics Service Providers in Vietnam.

• 한국통신학회논문지
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• 제38A권2호
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• pp.164-173
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• 2013

본 논문에서는 움직임 벡터의 정규화 및 윤곽선(edge)의 패턴 분석을 이용한 새로운 복수영상 기반의 초해상도(super resolution) 영상 생성 기법을 제안한다. 기존의 복수영상 기반의 초해상도 기법의 경우 입력 동영상을 구성하는 각 영상 간 부화소(sub-pixel) 단위의 움직임과 병진이동(global translation)만이 발생한다고 가정하여 기법의 적용이 제한적이다. 또한 이러한 제한에 강한 단일영상 기반의 초해상도 영상 생성 기법의 경우 보간 시 사용할 수 있는 정보량이 제한적이라는 단점이 있다. 본 논문에서는 기존 기법의 단점인 부화소 단위의 움직임에 대한 제한을 움직임 벡터의 정규화 기법을 통해 해결하고, 윤곽선 패턴 분석을 기반으로 한 2*2 블록 단위의 움직임 추정을 통해 병진이동에 대한 제한을 해결하였다. 또한 실험을 통하여 제안하는 기법이 기존의 이중선형(bi-linear)보간법, 단일영상과 복수영상 기반 초해상도 기법보다 우수하다는 것을 확인하였다.

• 한국농공학회논문집
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• 제54권2호
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• pp.55-65
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• 2012

In the winter season, when the ventilation system is operating, the fresh cold air from the slot-type openings of broiler house which directly reached the animal zone can cause various problems such as thermal stress, decreasing of feed and water consumption, occurrence of respiratory disease, and etc. Therefore it is very important to control the trajectory of aero-flow from the slot openings to induce an efficient thermal heat change. Jet-drop distance model was proposed to predict and control the jet-trajectory. However their study was restricted due to the small scaled model and difficulties of measuring the Jet-drop distance. In this study, CFD was applied to analyze qualitatively and quantitatively the jet-drop distance in a real broiler house. The various variables were considered such as installed slot-angle, designed ventilation rate, and the outdoor ambient temperature. From the present study, two linear-regression models using the Jet-drop factor and corrected Archimedes number, and their R-squared values 0.744 and 0.736, respectively, were used. From this study, the applicability of CFD on the analysis of Jet-drop distance model was confirmed.

• 한국농촌간호학회지
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• 제18권1호
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• pp.11-18
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• 2023

Purpose: This study is to compare adolescents' health behaviors by city size and to propose regionally tailored health promotion. Methods: We analyzed the data from the 17th Youth Health Risk Behavior Online Survey, national widly performed in 2021. Multi-sample descriptive and linear regression analysis was performed by city size. Results: The frequency of fruit consumption in the last week was 2.88 in the rural area, which is lower than 2.98 and 3.05 in other cities (F=10.98, p<.001). The number of high-intensity physical activity days in the last week (7 days) was 2.90 days in the rural area, higher than 2.74 and 2.73 days in other cities (F=3.36, p=.038). The number of days smoking cigarettes in the last 30 days was 3.23 days in the rural area, higher than 3.08 and 3.02 days in other cities (F=3.41, p=.035). BMI was 22.01 in the rural area, which was higher than 21.57 and 21.61 in other cities (F=4.19, p=.015). Conclusion: School health offices in the rural area districts need to operate to manage lack of fruit intake, smoking, and weight management programs in association with local healthcare institutions.

• 한국해안해양공학회지
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• 제19권2호
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• pp.128-135
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• 2007

해양수산부에서 연안에 설치한 기상 관측 장비로 측정된 우리나라 세 지역(낙동강 하구, 시화호, 마산만)의 기온과 수온 자료를 바탕으로 기온-수온의 비선형 상관관계를 분석하였다. 기온-수온 대표관계인 비선형 S-모형의 관계식에 포함된 4개의 매개변수를 결정하기 위해서 SCE 최적화 기법을 이용하였으며, 마산만 지역에서는 계절적 이력현상을 고려하여 서로 다른 관계식을 적용하였다. 기온-수온 상관 관계는 시간규모에 따른 최대 온도값과 최소 온도값에 차이가 있으나 수질 또는 생태 반응의 적당한 시간규모에 해당하는 주 평균 온도값을 이용하여 분석하였다. 전반적으로 연구지역인 하천과 해안이 접하는 우리나라 해안 및 하구 지역에서는 S-모형의 관계식이 선형 관계식보다 적합한 것으로 파악되었다. 이 연구는 기후변화 가설에 따른 미래의 수온변화에 반응하는 수질, 수문, 및 생태반응을 모의하여 공학기술자 또는 정책입안자에게 적절한 기후변화 대책 방향을 설정하는데 기여할 것으로 사료된다.

• Journal of Ecology and Environment
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• 제38권4호
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• pp.505-515
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• 2015

The objectives of this study were to determine the effects of stream nutrient regime, N:P ratios and suspended solids on fish tolerance/trophic compositions and stream ecosystem health, based on multi-metric model, during 2008-2013. Also, stream ecosystem health was evaluated in relation to chlorophyll-a (CHL) as a measure of algal productivity or indicators of trophic state to water chemical parameters. Total number of sampled fish species were 50 and showed a decreasing trend from 2008 to 2013. The minnow of Zacco platypus, based on the catch per unit effort (CPUE), was the most dominant species (25.9%) among the all species. Spatial heterogeneity was evident in the fish tolerance guilds that showed the dominance of sensitive species (89%) in the headwaters (S1) and the dominance of tolerant species (57%) in the urban. These conditions were directly influenced by concentrations of nutrients and organic matter (COD). The N:P ratios, as a barometer of water pollution, had a negative linear function (R² = 0.40, P < 0.01) with CHL, and the ratios had an important role in changes of COD concentration (R² = 0.40, P < 0.01). Under the circumstances, the N:P ratio directly influenced the relative proportions of fish trophic/tolerance compositions. According to the regression analysis of omnivore (O_m) and insectivore sp. (I_n) on total nitrogen and total phosphorus, nitrogen had no significant influences (P > 0.05) to the two compositions, but phosphorus influenced directly the two guilds [slope (a) = -32.3, R² = 0.25, P < 0.01 in the I_n; a = 40.7, R² = 0.19, P < 0.01 in the O_m]. Such water chemistry and fish trophic guilds determined the stream ecosystem health, based on the multi-metric fish model.