• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2003년도 학술발표논문집
• /
• pp.435-438
• /
• 2003

Model for estimating daily paddy water requirements was developed to simulate daily streamflow in upstream and downstream. Evapotranspiration in paddy fields was estimated using modified Penman equation. Daily water requirements in paddy fields were calculated from multiplication of paddy area to ponding depth decreased for one day. And model was constructed with a system form user-friendly and almost completely using controls of image, grid, and etc. in Visual Basic 6.0. The developed model was applied to estimate daily agricultural water requirements at 12 small watersheds during 20 years from 1983 to 2002 with paddy field areas of $3,332{\sim}26,422ha$ in small watersheds, and with agricultural water requirements of $37.22{\sim}294.53mcm$ on yearly average.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회 논문집
• /
• pp.138-142
• /
• 2005

The change of precipitation and temperature due to the global. warming eventually caused the variation of water availability in terms of potential evapotranspiration, soil moisture, and runoff. In this reason national long-term water resource planning should be considered the effect of climate change. Study of AOGCM-based scenario to proposed the plausible future states of the climate system has become increasingly important for hydrological impact assessment. Future climate changes over East Asia are projected from the coupled atmosphere-ocean general circulation model (AOGCM) simulations based on Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2 and B2 scenarios using multi-model ensembles (MMEs) method (Min et al. 2004). MME method is used to reduce the uncertainty of individual models. However, the uncertainty increases are larger over the small area than the large area. It is demonstrated that the temperature increases is larger over continental area than oceanic area in the 21st century.

• 한국생활과학회지
• /
• 제17권4호
• /
• pp.661-677
• /
• 2008

The purpose of this study is to develop the playground environment model for child care center by analyzing user needs of playground environment. To systemize the playground environment design factors and guidelines, we reviewed the previous research, actual measurement and observation were used as the research methodology. And to recognize the needs of users, the survey and picture survey was conducted to the staffs and children. The scope of survey included child care centers in Seoul and Daejeon, ultimately selecting 12 places in Seoul and 13 places in Daejeon. In terms of the survey period, actual measurement was conducted from June of 2006 to February of 2007, survey and picture survey was conducted from August to September of 2006. For analysis, we used SPSS 10.0 to check the frequency and percentage, as well as to perform cluster analysis. The findings of research can be summarized as below: 1. In playground environment, we observed the area of play ground and ground cover, the independence of play area, play equipment, and the composition of play area. The result of observation showed that while playground area varied widely, ground cover, play equipment, and the composition of play area turned out to be identical, regardless of the playground's area. Therefore, in order to classify various playground environments, we categorized them into 5 types, using the number of children and the area of play ground as a category. Type A had large facilities and small playground area. Type B had small sized facilities and large playground area. Type C had medium sized facilities and small playground area. Type D had medium sized facilities but large playground area. Type E had large sized facilities and large playground area. 2. On the other hand, staffs wanted a tunnel, playhouse, comprehensive play equipment, and a maze to be installed as play facilities, and there were requests for adventure play area and carpenter play area. The picture survey to children showed that they wanted equipments that can provide more thrill, adventure and challenge to them than the ones they see now. Therefore, existing child care center play environments must change from the monotonous and identical environments to the ones that can provide diversities, challenges, and adventures. In the contexts of 5 playground types suggested by this research, type B and D, E where the area of playground were larger than the legally required, should include various play areas and install appropriate play equipments and facilities. Type A and C where the area were small, should provide multipurpose play area to attract the various play behaviors of children.

• 한국물환경학회지
• /
• 제26권4호
• /
• pp.654-663
• /
• 2010

Attention has increasingly focused on the pollutant load discharged from rural area since the enforcement of total maximum daily loads (TMDLs) in korea. As one of the methods to control the inflow of pollutant load during wet weather events, local governments are attempting to apply non-point source control facility. To design those facilities appropriately, it is essential to understand the runoff characteristics of pollutants such as TSS, $BOD_5$, $COD_{Cr}$, TP and TN. In the paper, the quantitative analyses for pollutant runoff characteristics were examined in a small rural watershed with the area of about 53 hectares. For a dry weather day and wet weather events, variation patterns of dry weather flow and runoff characteristics of wet weather flows were monitored and investigated. The runoff model using XP-SWMM reflecting the landuse types of the watershed in detail was simulated to perform the sensitivity analyses for several factors influencing on their hydrograph and pollutographs. As a result, for the case of medium and small rainfall events (i. e. total rainfall of 35.8 and 17.5 mm), the impervious area including green house, roof and road which covers relatively low portion of total area (i. e. 16%) caused substantial first flush and the majority of total runoff load. Therefore, it has been concluded that the runoff characteristics of each pollutant and distribution of impervious area should be considered for the establishment of the control strategy of non-point pollutant runoff at a rural area.

• 대한의용생체공학회:의공학회지
• /
• 제26권1호
• /
• pp.17-22
• /
• 2005

Small animal PET using a dual layer phoswich detector has been developed to obtain high and uniform spatial resolution. In this study, a simple analytic model to optimize the lengths of a dual layer phoswich detector was derived and validated by Monte Carlo simulation. For a small animal PET scanner with a 10㎝ ring diameter, the optimal length of the phoswich detector consisting of various crystal materials, such as LSO and LuYAP, were calculated analytically and validated using GATE. The detector module consisted of 8×8 arrays of crystals, with each phoswich detector element having a 2㎜×2㎜ sensitive area. The total crystal length was fixed to 20㎜. The optimal lengths of the phoswich detector layers, as functions of the crystal materials and order, conveniently derived by the analytic equation, showed good agreement with those estimated by the time consuming simulation. The simple analytical model can be used for the fast and accurate design of an optimal phoswich detector for small animal PET to achieve high spatial resolution and uniformity.

• 한국멀티미디어학회논문지
• /
• 제24권3호
• /
• pp.373-381
• /
• 2021

In this paper, we propose a classification model based on convolutional neural network(CNN) for predicting 2-year recurrence in non-small cell lung cancer(NSCLC) patients using preoperative chest CT images. Based on the region of interest(ROI) defined as the tumor internal and external area, the input images consist of an intratumoral patch, a peritumoral patch and a peritumoral texture patch focusing on the texture information of the peritumoral patch. Each patch is trained through AlexNet pretrained on ImageNet to explore the usefulness and performance of various patches. Additionally, ensemble learning of network trained with each patch analyzes the performance of different patch combination. Compared with all results, the ensemble model with intratumoral and peritumoral patches achieved the best performance (ACC=98.28%, Sensitivity=100%, NPV=100%).

• Journal of the Korean Data and Information Science Society
• /
• 제28권3호
• /
• pp.505-513
• /
• 2017

최근, 더욱 상세하고 정확한 추정 결과를 위해 소지역추정(small area estimation; SAE)의 연구가 많이 진행되고 있다. 그 중 공간회귀모형 (spatial regression model)을 이용한 방법이 주를 이루고 있는데 이를 사용하기 위해서는 공간이웃 (spatial neighbor)의 정의가 필요하다. 본 연구에서는 공간이웃을 정의하는 방법으로 도로네 삼각망 (Delaunay triangulation; DT)을 소개하고 k-최근접 (k-nearest neighbor; KNN)과 비교하여 분석한다. 두 가지 공간이웃을 정의하는 방법중에서 어떤 방법으로 이웃을 정의하는 것이 효율적인지 알아보기 위해 시뮬레이션을 실시하였고, 지가 (land price)데이터를 이용하여 실 데이터를 분석하였다.

• 한국수자원학회논문집
• /
• 제41권6호
• /
• pp.643-651
• /
• 2008

본 연구는 소규모 수리시설물이 장기유출에 끼치는 영향에 대해 시 공간적으로 상세히 분석하고, 분석된 결과를 토대로 장기유출 모의모형에 소규모 수리시설물의 영향을 반영할 수 있도록 구성함으로서 유역의 장기유출 모의결과의 신뢰도를 증진시키는 것이 목적이다. 따라서 본 연구에서는 대상유역의 소규모 수리시설물 현황을 파악하고 각 수리시설물별로 하천유량에 끼치는 영향을 분석한 후, 수리시설물의 영향을 고려할 수 있도록 강우-유출 모형을 구축하였다. 수리시설물에 의한 영향평가를 실시한 결과, 공간적으로는 저수지가 많이 분포한 소유역에서, 시기적으로는 강우가 풍부했던 2003년을 제외한 2/4분기에서 모형상 에러인 음의 유량 발생빈도가 크게 나타났다. 따라서 본 연구에서는 수리시설물의 영향평가를 토대로 유출량과 수리시설물의 상관식을 유도하였으며 이를 이용하여 강우-유출 모의를 재구성하였다. 그 결과 모의유량은 상대적으로 수리시설물을 고려하지 않은 경우보다 오차가 크게 감소하였다.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2001년도 추계 학술대회논문집
• /
• pp.44-50
• /
• 2001

A numerical study was made to choose the better turbulence model for the flow in the discharge flow path from a diffuser to a wall. In this study standard $\kappa-\epsilon$ model(SKE), RNG $\kappa-\epsilon$ model(RNG), and Reynolds stress model(RSM) were applied. In case of the flow with relatively high Reynolds number at a diffuser inlet, the pressure loss coefficients by RNG have a tendency to be near to those by SKE at small ratio(below about 0.35) of $h/D_o$, but to those by RSM at large ratio(above about 0.35). At large ratio RNG begins to enlarge the effects of rapid strain and streamline curvature. RNG & RSM are recommended as the appropriate turbulence models for this case. But it is noticeable that the velocity gradient pattern in RNG is same as in SKE, and also that the total pressure distribution in RNG is same as in RSM only at swirling flow area, same as in SKE only at main flow area.

• Communications for Statistical Applications and Methods
• /
• 제30권5호
• /
• pp.501-516
• /
• 2023

Knowledge distillation (KD) refers to extracting knowledge from a large and complex model (teacher) and transferring it to a relatively small model (student). This can be done by training the teacher model to obtain the activation function values of the hidden or the output layers and then retraining the student model using the same training data with the obtained values. Recently, relational KD (RKD) has been proposed to extract knowledge about relative differences in training data. This method improved the performance of the student model compared to conventional KDs. In this paper, we propose a new method for RKD by introducing a new loss function for RKD. The proposed loss function is defined using the area difference between the teacher model and the student model in a specific hidden layer, and it is shown that the model can be successfully compressed, and the generalization performance of the model can be improved. We demonstrate that the accuracy of the model applying the method proposed in the study of model compression of audio data is up to 1.8% higher than that of the existing method. For the study of model generalization, we demonstrate that the model has up to 0.5% better performance in accuracy when introducing the RKD method to self-KD using image data.