• 한국지반환경공학회 논문집
• /
• 제15권1호
• /
• pp.69-77
• /
• 2014

본 연구의 목적은 소하천 유역에 대한 홍수범람해석 모형을 비교하는 것이다. 검청천을 대상으로 1차원 수리모형인 HEC-RAS와 범람해석을 위한 HEC-GeoRAS, RAS Mapper, RiverCAD 모형을 적용하여 홍수범람해석을 수행하였다. 실측 강우량과 빈도별 홍수량을 적용하여 3가지 모형에 따른 홍수범람해석을 모의하였으며, 해석결과와 당시 조사된 침수흔적도를 비교하고 각 모형들의 빈도별, 침수심별에 따라 홍수범람면적을 비교하였다. 실측 강우량을 적용하여 해석된 홍수범람면적은 HEC-GeoRAS 모형의 결과가 침수흔적도와 비교적 유사하게 나타났다. 또한, 빈도별 설계홍수량을 적용하여 해석된 범람면적은 RAS Mapper 모형이 가장 크게 나타났으며, 3가지 모형의 전체 범람면적 차이가 10% 이내로 비교적 유사한 결과를 나타내었다. 침수심별 범람면적을 비교한 결과 침수심 2.0 m 이하 구간에서는 3가지 모형의 결과가 비교적 유사하게 나타났으며, 침수심 2.0 m 이상의 구간에서 RiverCAD 모형의 범람면적이 비교적 큰 차이를 나타내었다.

• 농업과학연구
• /
• 제45권3호
• /
• pp.521-532
• /
• 2018

In recent decades, the dry stream phenomena of small and medium sized rivers have been attracting much attention as an important social problem. To prevent dry stream phenomena, it is necessary to build an infrastructure that manages rivers. To accurately determine the progress of dry stream phenomena, it is necessary to continuously measure the discharge and other hydrological factors for small and medium sized rivers. However, until now, the flow data for small and medium rivers in Korea has been insufficient. To overcome the lack of supporting data for supporting rational decision-making in policy and project implementation, a short- and long-term hydrological model was developed that takes into consideration hydrological changes such as the increase of the impervious area due to urban development and groundwater pumping, the construction of a large-scale sewage treatment plant, the maintenance of stream-oriented rivers, etc. In the developed model, the distributed grid is represented by three layers: Surface flow, interflow, and groundwater flow. The surface flow and intermediate flow flowed along the flow direction, and the groundwater flow was calculated by a two-dimensional groundwater analysis model such that the outflow occurred in all directions without a specific flow direction. The effects of land use and cover on evapotranspiration and infiltration and the effects of multiple landscapes can be simulated in the developed model.

• 한국항해항만학회지
• /
• 제31권10호
• /
• pp.813-818
• /
• 2007

선박의 선형시험설비로는 회류수조, 예인수조 등이 있으나, 소형 고속선박은 실선 대응 모형선의 축적비가 대형선에 비해 매우 작고 수조의 유속과 예인전차의 속도제한으로 고속선의 설계선속까지의 성능검증에는 한계로 작용하였다. 이에, 고속 활주형선의 선형시험 검증을 위해 실 해상모형시험기법을 정립하였다. 한편, 고속 Stepped Hull선형은 일체형 활주형 선저선형에 비하여 고속 주행시 공기공급에 따른 접수면 감소로 인하여 저항감소에 따른 속도향상과 연비절감 효과가 있으나, 선미 좌우측의 접수면 감소에 따른 횡동요 안정성이 감소되는 경향이 있다. 이에, 본 논문에서는 고속 선형시험이 가능한 해상모형시험을 이용하여 선미 보조동체 장착 유무에 따른 고속 Stepped Hull 선형의 횡동요 및 저항특성을 비교, 분석한 것이다.

• 한국산업융합학회 논문집
• /
• 제10권2호
• /
• pp.89-96
• /
• 2007

For the environment protection, carbon dioxide as a natural refrigerant has been studied to use in an automotive air conditioning system. Hence, a numerical model has been developed to describe the evaporation phenomena of carbon dioxide flowing through very small diameter tubes. The two dimensional low-Reynolds $k-{\varepsilon}$ model was used to predict the flow phenomena of carbon dioxide in the two phase during its evaporation. Furthermore, the results obtained from the model were compared with the experiments for the validation. The heat transfer coefficient is lower, as the tube inner diameter becomes smaller. However, the amount of heat absorbed by a unit mass of carbon dioxide is greater due to more surface area. Therefore, the small diameter tube has advantage in terms of compact design of evaporator. When the inlet condition of pressure and temperature is low, the heat transfer coefficient is slightly high at the same size of tube because of the thermal properties of carbon dioxide.

• 한국학교보건학회지
• /
• 제28권2호
• /
• pp.67-78
• /
• 2015

The purpose of the study was to present a model of WHO Health Promoting School easily applicable to small-sized schools in rural areas. Methods: The study analyzed data of 11 small-sized schools in rural areas selected from 85 health promoting schools, an initiative led by the Ministry of Education from 2012 to 2014. Results: Through the analysis, the study found out the operation process of health promoting schools consists of five stages: system development, needs survey & survey on current status, school health policy development, program development & execution, and evaluation. In addition, the study was able to discover three key factors in operating health promoting schools: connection with curriculum, connection with community, and consensus among members. While it turned out the schools were following operation manuals faithfully, the biggest problem with operation was that the stages of needs survey, priority setting, and core task development were not closely coordinated. Conclusion: Although the model suggested in the study fails to reflect the characteristics of small-sized schools in rural areas, it is close to a universal model which could serve as a guideline when regular schools adopt the system of health promoting schools.

• 로봇학회논문지
• /
• 제15권2호
• /
• pp.184-189
• /
• 2020

This paper is a study on data augmentation for small dataset by using deep learning. In case of training a deep learning model for recognition and classification of non-mainstream objects, there is a limit to obtaining a large amount of training data. Therefore, this paper proposes a data augmentation method using perspective transform and image synthesis. In addition, it is necessary to save the object area for all training data to detect the object area. Thus, we devised a way to augment the data and save object regions at the same time. To verify the performance of the augmented data using the proposed method, an experiment was conducted to compare classification accuracy with the augmented data by the traditional method, and transfer learning was used in model learning. As experimental results, the model trained using the proposed method showed higher accuracy than the model trained using the traditional method.

• 한국환경과학회지
• /
• 제16권1호
• /
• pp.95-102
• /
• 2007

The paper aims to highlight residents' preference of park close to industrial area in Seo-gu, Daegu City. Questionnaire survey was the main research method for the study from June to August last year. There were 2 survey questionnaires, one is for satisfaction degree regarding residents' general park use and the other is especially for vest-pocket use. For the research, 150 questionnaires were surveyed for each park users(total 300 questionnaires) and 270 questionnaires are used for the statistical analysis. The analysis showed that small vest pocket sized park was the proper model for close to industrial area. The majority residents preferred small park close to a residential area, also 77% of residents who use vest-pocket park replied that they live within 10 minute walking distance from there. In the case of Seo-gu, there were several small vest pocket sized parks which can satisfy the residents' preference. Therefore the plan which utilize them positively is necessary.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
• /
• pp.166-169
• /
• 2004

NDVI has been used to estimate several ecological variables including leaf area index (LAI). Global MODIS LAI data are partially produced by empirical model that is based on the assumption of high correlation between NDVI and LAI. This study attempts to evaluate the MODIS empirical model by comparing with the result obtained from field LAI measurement and Landsat ETM+ reflectance. MODIS LAI product and ancillary data were analyzed over a small forest watershed near the Seoul metropolitan area. The relationship between NDVI of ETM+ and field measured LAI did not correspond to MODIS LAI estimation. Since the study area is mostly covered by very dense and fully closed forest, the correlation between NDVI and LAI might not be high. Although MODIS LAI product has great potential for global environment studies, it needs to be cautious to use them in regional and local area in particular for the forest of dense canopy situation.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집B
• /
• pp.673-679
• /
• 2000

LNG Carriers are currently known as sole commercial means of shipping natural gas on the sea. They are designed to proven dangerous explosion for shipping a lot of gas over long distance. In this study. In this study, a scaled model chamber was made to investigate ventilation characteristics of the hood room in LNG carrier. Experimental study was performed in model using visualization equipments with laser apparatus and image intensifier CCD camera gated by an AOM controller Twelve different kinds of measuring area were selected as experimental condition. Instant simultaneous velocity vectors at whole field were measured by using 2-D PIV system which software adopts two-frame grey-level cross correlation algorithm. To look into stagnation area of hood room for LNG carrier, a three-dimensional numerical simulation with standard ${\kappa}-{\varepsilon}$ model was carried out by using PHOENICS for three kinds of Reynolds number, $6.5{\times}10^3$, $9.7{\times}10^3\;and\;1.29{\times}10^4$, based on the cavity inlet velocity and cavity height. The flow pattern showed the large scale counter-clockwise forced-vortex rotated at center area, small eddies at each corner and stagnation area located at left-back upper side of model.

• 응용통계연구
• /
• 제21권4호
• /
• pp.665-674
• /
• 2008

기존의 소지역추정 연구에서는 대부분 특정 시점에서의 관심 모수를 추정하는 문제를 다루어 왔다. 그러나 대부분의 공식통계들은 월, 분기, 또는 년 단위로 반복적으로 얻어지는 패널자료이기 때문에 이를 고려한 추정방법이 필요하다. 이 논문에서는 반복측정 또는 다시점자료 분석에 유용하게 사용되고 있는 일반화추정방정식을 이용한 실증분석을 통해 소지역추정에서 시간종속성을 포함시키는 방안을 알아본다. 실증분석에서는 2005년 1월에서 12월까지의 경상남도 및 울산광역시 월별 경제활동인구조사 자료를 바탕으로 시군구별 실업률과 실업률에 영향을 줄 것으로 생각되는 설명변수의 관계를 일반화선형모형과 일반화추정방정식을 적용하여 분석해 보고 시간종속성을 고려한 것과 하지 않은 것을 비교해 본다.