• 한국농림기상학회지
• /
• 제6권3호
• /
• pp.164-169
• /
• 2004

A spatial interpolation scheme incorporating local geographic potential for cold air accumulation (TOPSIM) was used to test the feasibility of operational frost warning in Chatancheon basin in Yeoncheon County, where the introduction of new crops including temperate zone fruits is planned. Air temperature from April to June 2003 was measured at one-minute intervals at four locations within the basin. Cold-air accumulation potentials (CAP) at 4 sites were calculated for 3 different catchment scales: a rectangular area of 65 x 55 km which covers the whole county, the KOWACO (Korea Water Corporation) hydrologic unit which includes all 4 sites, and the sub-basins delineated by a stream network analysis of the digital elevation model. Daily minimum temperatures at 4 sites were calculated by interpolating the perfect prognosis (i.e., synoptic observations at KMA Dongducheon station) based on TOPSIM with 3 different CAPs. Mean error, mean absolute error, and root mean square error were calculated for 45 days with no precipitation to test the model performance. For the 3 flat locations, little difference was detected in model performance among 3 catchment areas, but the best performance was found with the CAPs calculated for sub-basins at one site (Oksan) on complex terrain. When TOPSIM loaded with sub-basin CAPs was applied to Oksan to predict frost events during the fruit flowering period in 2004, the goodness of fit was sufficient for making an operational frost warning system for mountainous areas.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.948-951
• /
• 2014

Road traffic noise is closely related with urban forms and urban components, such as population, building, traffic and land-use, etc. Hence, it is possible to minimize the noise exposure problem depending on how to plan new town or urban planning alteration. This paper provides ways to apply for urban planning in consideration of noise through exposed noise estimation for urban planning alteration. Spatial autoregressive model which explains about 81.4% of road traffic noise from the former paper is used. The simulation results by the spatial statistical model are compared with those by the engineering program-based modeling for 5 small-scaled scenarios of urban planning alteration. The error from the limitation of containing informations inside the grid cell and the difficulties of reflecting acoustic phenomena is existed. Nevertheless, in the stage of preliminary design, the use of the statistical models that have been estimated well is useful in time and economically.

• 인간식물환경학회지
• /
• 제24권5호
• /
• pp.529-544
• /
• 2021

Background and objective: A great deal of previous research has highlighted the value of educational and cultural facilities embedded in housing prices, by taking a large spatial area as the focus, such as the city or district level. However, few studies have investigated the extent to which educational and cultural facilities influence the formation of housing prices from an accessibility perspective. This study aims to identify the value of educational and cultural facilities embedded in the housing prices in Seoul Metropolitan City with a focus on the concept of the residents' neighbourhood and accessibility. Methods: To this end, this research used a spatial regression model with educational and cultural facilities as the independent variables and housing prices as the dependent variable. The model assessed the accessibility of cultural and educational facilities by considering geographic effects. Results: The findings are as follows. First, the spatial error model was found to be the best fit for multi-unit housing, while the spatial lag model was more appropriate for single-unit housing and apartments. Second, private educational facilities and art museums had positive effects on single- and multi-unit housing prices, while historical sites had a negative effect. Finally, private educational facilities positively influenced apartment prices, whereas public libraries and urban park areas had a negative effect. Conclusion: These findings indicate that the accessibility of educational and cultural facilities reflects residents' preferences and needs, which will ultimately influence housing prices.

• ETRI Journal
• /
• 제40권1호
• /
• pp.122-132
• /
• 2018

This paper proposes a hierarchical dual filtering (HDF) algorithm to estimate the spatial region between a Cloud of Things (CoT) gateway and an Internet of Things (IoT) device. The accuracy of the spatial region estimation is important for autonomous CoT clustering. We conduct spatial region estimation using a hidden Markov model (HMM) with a raw Bluetooth received signal strength indicator (RSSI). However, the accuracy of the region estimation using the validation data is only 53.8%. To increase the accuracy of the spatial region estimation, the HDF algorithm removes the high-frequency signals hierarchically, and alters the parameters according to whether the IoT device moves. The accuracy of spatial region estimation using a raw RSSI, Kalman filter, and HDF are compared to evaluate the effectiveness of the HDF algorithm. The success rate and root mean square error (RMSE) of all regions are 0.538, 0.622, and 0.75, and 0.997, 0.812, and 0.5 when raw RSSI, a Kalman filter, and HDF are used, respectively. The HDF algorithm attains the best results in terms of the success rate and RMSE of spatial region estimation using HMM.

• 대한원격탐사학회지
• /
• 제39권6_1호
• /
• pp.1517-1522
• /
• 2023

본 연구에서는 Second Simulation of the Satellite Signal in the Solar Spectrum Vector를 활용하여 Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD)의 기대 오차(expected error, EE)가 KOMPSAT-3A 지표반사도(surface reflectance, SR)의 정확도에 미치는 영향을 평가한다. 연구에서 다양한 지상 AOD와 그에 따른 MODIS AOD EE를 고려함으로써, 파장이 짧고 태양천정각(solar zenith angle, SZA)이 높을수록 SR 오류가 증가한다는 결과를 확인했으며, 이는 파장과 SZA 고려 사항을 통합하여 대기보정 알고리즘을 개선하기 위한 추가 연구가 필요하다는 점을 강조한다. 또한, 이 연구는 대기보정 과정에서 다른 위성의 AOD 자료 활용에 대해 더 잘 이해하기 위한 기초 자료를 제공하고 대기보정 기술 발전에 기여할 것으로 예상한다.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제14권3호
• /
• pp.189-200
• /
• 2010

A numerical method is proposed and analyzed to approximate a mathematical model of age-dependent population dynamics with spatial diffusion. The model takes a form of nonlinear and nonlocal system of integro-differential equations. A finite difference method along the characteristic age-time direction is considered and primal mixed finite elements are used in the spatial variable. A priori error estimates are derived for the relevant variables.

• 한국농림기상학회지
• /
• 제2권4호
• /
• pp.175-182
• /
• 2000

표준관측소의 점 단위 기온 관측 및 예보값을 농업분야에서 활용하기 위해서는 공간내삽이 필요한 경우가 많지만 기후학적 평년값 같은 장기간의 평균값 내삽과는 달리 지형효과를 반영하기 어려워 거리역산가중법이 수정 없이 사용되고 있다. 우리 나라처럼 지형이 복잡한 산악지역에서는 수평 거리에만 의존한 내삽 결과에 심각한 오류가 포함될 수 있으므로, 영농지원 정보로서 중요한 일 최저기온을 대상으로 추정오차의 최대근원인 해발고도의 영향을 보정 할 수 있는 간단한 공간내삽모형을 작성하였다. 먼저 남한 육지 상에 위치한 63개 표준관측소에서 수집된 일 최저기온자료와 관측소의 위치, 해안으로부터 거리, 경사향, 표고 등 국지기온 결정인자를 회귀분석 하여 표고에 따른 기온감율 추정식을 날짜의 함수로 표현하였다. 63개 관측점의 표고값을 공간내삽 하여 재구성한 전국의 가상 지형으로부터 1 km$\times$ 1 km 공간단위의 전국 수치고도값 편차를 계산하고, 여기에 해당 날짜의 기온감율을 적용하여 보정값을 계산한다. 기존의 거리역산가중법에 의한 기온추정값을 이 보정값에 의해 수정함으로써 최종 기온값을 얻는다. 임의로 선발된 1999년의 월별 하루씩 총 12일에 대하여 이 모형과 기존 거리역산가중법을 각기 적용하여 267개 자동기상관측지점의 일 최저기온을 추정한후 실측값과 비교하였다 오차평균, 절대오차평균, 그리고 평방근오차평균 등 세가지 추정오차를 분석한 결과 이 방법이 거리역산가중법에 비해 산악지역에서의 일 최저기온 추정에 있어 뚜렷한 개선효과를 보였다.

• 말소리와 음성과학
• /
• 제2권3호
• /
• pp.141-148
• /
• 2010

In this paper, voice activity detection (VAD) for dual-channel noisy speech recognition is proposed in which spatial cues are employed. In the proposed method, a probability model for speech presence/absence is constructed using spatial cues obtained from dual-channel input signal, and a speech activity interval is detected through this probability model. In particular, spatial cues are composed of interaural time differences and interaural level differences of dual-channel speech signals, and the probability model for speech presence/absence is based on a Gaussian kernel density. In order to evaluate the performance of the proposed VAD method, speech recognition is performed for speech segments that only include speech intervals detected by the proposed VAD method. The performance of the proposed method is compared with those of several methods such as an SNR-based method, a direction of arrival (DOA) based method, and a phase vector based method. It is shown from the speech recognition experiments that the proposed method outperforms conventional methods by providing relative word error rates reductions of 11.68%, 41.92%, and 10.15% compared with SNR-based, DOA-based, and phase vector based method, respectively.

• 방송공학회논문지
• /
• 제17권6호
• /
• pp.1048-1060
• /
• 2012

본 논문에서는 영상에 포함되어 있는 잡음을 효율적으로 제거하기 위해 원본 영상과 잡음이 포함된 영상 사이의 mean square error (MSE) 추정에 기반한 적응적인 시공간 디노이징 필터(Adaptive Temporal and Spatial De-noising Filter : ATSF)를 제안하였다. 제안하는 디노이징 필터는 잡음이 포함되어 있는 영상에 블록 단위로 적용되며, 시간적 필터인 Multi-Hypothesis Motion Compensated Filter (MHMCF)를 사용하고, 공간적 필터로는 bilateral filter를 사용하였다. 각각의 블록에 대해 시간적 필터와 공간적 필터 중에서 최적의 필터를 선택하기 위해서 잡음이 포함되지 않은 원본 영상과 잡음이 포함된 입력 영상 사이의 MSE를 추정하는 기법을 제안하였다. 디노이징 단계에서 원본 영상이 주어지지 않기 때문에 MSE를 추정하기 위해서, 본 논문에서는 MHMCF가 적용된 블록의 MSE를 수학적으로 예측하고, bilateral filter가 적용된 블록의 MSE를 통계적 선형 모델을 통해 예측하였다. 이렇게 예측된 MSE를 비교하여 더 작은 MSE를 갖는 필터를 선택적으로 매 단위 블록마다 적용하게 된다. 제안된 방법은 시간적 필터와 공간적 필터를 적응적으로 적용함으로써 기존의 디노이징 방법에 비해 객관적 화질 뿐만 아니라 주관적인 화질에서 우수한 성능을 보여준다.

• 한국소음진동공학회논문집
• /
• 제25권4호
• /
• pp.284-290
• /
• 2015

Road traffic noise is closely related with urban forms and urban components, such as population, building, traffic and land-use, etc. Hence, it is possible to minimize the noise exposure problem depending on how to plan new town or urban planning alteration. This paper provides ways to apply for urban planning in consideration of noise exposure through road traffic noise estimation for alteration of small-scale urban form. Spatial autoregressive model from the former study is used as statistical model for noise simulation. The simulation results by the spatial statistical model are compared with those by the engineering program-based modeling for 5 scenarios of small-scale urban form alteration. The error from the limitation of containing informations inside the grid cell and the difficulties of reflecting acoustic phenomena exists. Nevertheless, in the stage of preliminary design, the use of the statistical models that have been estimated well could be useful in time and economically.