• Journal of Korea Water Resources Association
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• v.42 no.2
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• pp.131-139
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• 2009

The weather accidents by global warming effect are increasing rapidly whole world. Flood forcasting system and hydrological database are operated by almost all the countries in the world. An objective of this study is to research revised methods of missing rainfall data and find more effective revised method for this operating system. 194 rainfall data of the Han river basin is used. Arithmetic average method, coefficient of correlation weighting method and inverse distance weighting method are compared to estimate revised methods. The result from the analysis shows that coefficient of correlation weighting method is best quantitatively among the 3 methods.

• Spatial Information Research
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• v.20 no.5
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• pp.77-89
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• 2012

Walking is the most basic personal mobility and its importance and concern is ever increasing with the highlighting of a new paradigm, such as transit oriented development, sustainable development and revitalization of green transport. The existing analytical research on pedestrian network is using a pedestrian's moving distance to a destination and integration in space syntax theory as its representative accessibility factors. However, the uniplanar network moving distance fails to reflect topographic characteristics, so the moving distance could show a similar result value in case of the regions for analysis that have a similar network structure to each other. Accordingly, the aim of this study is to suggest a new analytical methodology on pedestrian network accessibility in consideration of the grade in pedestrian sections and a pedestrian's size. this study, in its analysis of a uniplanar pedestrian network moving distance, analyzed the pedestrian network moving distance in consideration of the grade in pedestrian sections, and even the pedestrian network moving distance in consideration of a pedestrian's size, and suggested the methodology on pedestrian network accessibility analysis in consideration of a more substantive pedestrian's characteristics. It is hoped that the methodology used by this study will be used as the methodology on pedestrian network analysis which can reflect topographic characteristics in the pedestrian network analysis, and take a more substantive pedestrian's movement into account.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.104-104
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• 2019

기후 관측자료의 경우 관측, 가공, 전송 중에 오류가 발생할 수 있으며, 특히 글로벌 기후자료는 다양한 조건을 가지고 있는 자료를 수집하였기 때문에 일반적으로 해당 국가 관측자료보다 품질이 낮다. 본 연구에서는 글로벌 기후 관측자료의 품질을 개선할 수 있는 품질관리 기법을 개발하고 국내 지역에 적용해보고자 한다. 연구대상지역으로 국내 대표도시 7 곳을 선정하였으며, 글로벌 기후자료는 NCDC (National Climatic Data Center)의 일 단위 GSOD (Global Surface Summary of the Day) 자료를 수집하였다. 품질관리는 강수와 기온에 대해서 실시하였으며 과정은 크게 이상치 검사, 이상치 및 결측치 보정, 연, 월 단위 기후 자료 산정으로 구분된다. 이상치 검사는 중복성 검사, 내적일치성 검사, 기후범위 검사, 공간동질성 검사를 기반으로 구성되어 있다. 이상치 및 결측치 보정은 인접 관측소의 자료를 보간하여 수행하였으며, 보간기법은 4 방향 역거리 가중법을 활용하였다. 연, 월 단위 자료 산정은 자료의 결측률을 고려하여 일 단위 자료를 연, 월 단위 자료로 변환하는 과정이다. 이상치 검사 결과 대부분의 이상치는 기후범위와 공간동질성 검사에서 발견되는 것으로 나타났으며, 중복성 및 내적일치성 검사는 이상치 검출 효과가 적은 것으로 나타났다. 결측치 및 이상치 보간 결과 추정된 자료와 관측값 간의 상관관계가 있는 것으로 나타나 활용성이 있었다. 본 연구는 글로벌 자료의 품질관리 기법을 제시하였다는 점에서 활용성이 있으며, 향후 품질관리 기법의 검증에 관한 연구를 수행할 필요가 있다.

• The Journal of the Acoustical Society of Korea
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• v.21 no.6
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• pp.552-558
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• 2002

Recently, based on the human speech recognition (HSR) model of Fletcher, the multi-band speech recognition has been intensively studied by many researchers. As a new automatic speech recognition (ASR) technique, the multi-band speech recognition splits the frequency domain into several sub-bands and recognizes each sub-band independently. The likelihood scores of sub-bands are weighted according to reliabilities of sub-bands and re-combined to make a final decision. This approach is known to be robust under noisy environments. When the noise is stationary a sub-band SNR can be estimated using the noise information in non-speech interval. However, if the noise is non-stationary it is not feasible to obtain the sub-band SNR. This paper proposes the inverse sub-band distance (ISD) weighting, where a distance of each sub-band is calculated by a stochastic matching of input feature vectors and hidden Markov models. The inverse distance is used as a sub-band weight. Experiments on 1500∼1800㎐ band-limited white noise and classical guitar sound revealed that the proposed method could represent the sub-band reliability effectively and improve the performance under both stationary and non-stationary band-limited noise environments.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.3-12
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• 2011

Understanding of water sediment trends is an important part of water quality monitoring. Water quality variables change over time and space, and cannot be modeled or explained clearly by either temporal or spatial analysis alone. This research analysed the trends of temperature, pH levels and dissolved oxygen levels based on the sediment records and spatial data obtained in Lower Mekong Basin (LMB) during 1985-2005. Our aim is to evaluate spatio-temporal trends and graphical analyses using an Inverse Distance Weighting (IDW) interpolation method. The main results from this research can be summarized as follows. The maximum temperature and pH have been stable during the study period and the maximum dissolved oxygen has been increasing gradually until 2002. The minimum pH and dissolved oxygen have been changing in an unsteady trend during the period. A spatial analysis shows that the water temperature in this region has been increasing over time. The pH trend shows that it is decreasing during 1993-2005. Dissolved oxygen concentration has been increasing from 1989 onwards and stays in that track.

• Journal of the Korean earth science society
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• v.40 no.3
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• pp.259-271
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• 2019

A statistical downscaling method was adopted in order to establish the high-resolution wave prediction system in the East Sea coastal area. This system used forecast data from the Global Wave Watch (GWW) model, and the East Sea and Busan Coastal Wave Watch (CWW) model operated by the Korea Meteorological Administration (KMA). We used the CWW forecast data until three days and the GWW forecast data from three to seven days to implement the statistical downscaling method (inverse distance weight interpolation and conditional merge). The two-dimensional and station wave heights as well as sea surface wind speed from the high-resolution coastal prediction system were verified with statistical analysis, using an initial analysis field and oceanic observation with buoys carried out by the KMA and the Korea Hydrographic and Oceanographic Agency (KHOA). Similar to the predictive performance of the GWW and the CWW data, the system has a high predictive performance at the initial stages that decreased gradually with forecast time. As a result, during the entire prediction period, the correlation coefficient and root mean square error of the predicted wave heights improved from 0.46 and 0.34 m to 0.6 and 0.28 m before and after applying the statistical downscaling method.

• Journal of the Korean Solar Energy Society
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• v.37 no.6
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• pp.79-91
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• 2017

The meteorological data of 1 hour interval are required to write a typical weather data for building energy simulation. However, many meterological data are missing and the interpolation method to recover the missing data is required. Especially, lots of meterological data are replicated by linear interpolation method because the changes are not significant. While, the wind velocity fluctuates with the time or locations, so linear interpolation method is not appropriate in interpolation of the wind velocity data. In this study, three interpolation methods, using surrounding wind velocity data, Inverse Distance Weighting (IDW), Revised Inverse Distance Weighting (IDW-r), were analyzed considering the characteristics of wind velocity. The Revised Inverse Distance Weighting method, proposed in this study, showed the highest reliability in restoration of the wind velocity data among the analyzed methods.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.22.2-22.2
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• 2011

이 연구에서는 한반도 상공의 전리층 총전자수를 격자 형태로 나타냈다. 이를 위해 국토해양부 GPS 상시관측소에서 제공 중인 코드와 위상 측정값을 선형조합하였으며 그 결과물을 이용하여 시선방향 총전자수를 산출하였다. 이때 전리층 총전자수 산출결과의 정확도를 향상시키기 위해 가중최소자승법을 이용하여 위성과 수신기의 하드웨어 오차인 DCB(Differencial Code Bias)를 추정하였으며 추정된 DCB값은 IGS에서 제공 중인 DCB값과 비교하여 정확도를 확인하였다. 산출된 시선방향 총전자수를 연직방향 총전자수로 변환하기 위해 사상함수를 적용하였으며, 이를 다시 각 격자점에서의 연직방향 총전자수로 변환하기 위해 기존 연직방향 총전자수에 역거리 가중 보간법을 적용하였다. 각 격자점에서의 총전자수는 IGS(International GNSS Service)에서 제공 중인 GIM(Global Ionosphere Map) 모델의 총전자수와 비교하여 정확도를 확인하였다. 산출된 총전자수는 2시간 간격으로 나타내어 한반도 상공 전리층 총전자수의 변화 경향을 확인하였다.

• Proceedings of the Korean Statistical Society Conference
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• 2003.05a
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• pp.149-150
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• 2003

소표본 분할표 자료에서 적합도 검정통계량들의 카이제곱 근사 적용 가능에 대하여 많은 연구가 진행되었다. 소표본에서 세 가지 검정 통계량(피어슨 카이제곱 $X^{2}$, 일반화 가능도비 $G^{2}$, 그리고 역발산 I(2/3) 검정통계량)에 관하여 비교한 Rudas(1986)의 연구를 확장하여, 최근에 제안된 차이측도(BWHD(1/9), BWCS(1/3), NED(4/3) 검정통계량)를 포함시켜 비교 분석하였다. 독립모형의 이차원 분할표, 조건부 독립모형과 한 변수 독립 모형을 따르는 삼차원 분할표에 대한 모의실험을 통하여 생성된 90과 95 백분위수와 이에 대응하는 95% 신뢰구간을 살펴보고 실제 백분위수와 비교하였다. 그 결과 $X^{2}$, I(2/3), 그리고 BWHD(1/9) 검정통계량이 유사한 결과를 나타내었고 이 통계량들이 기존에 제안된 검정통계량들보다 적은 표본크기에서도 카이제곱 근사방법에 적용 가능함을 발견하였다.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.7-13
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• 2020

Meteorology and climate are closely related to human life. By using high-resolution weather data, services that are useful for real-life are available, and the need to produce high-resolution weather data is increasing. We propose a method for super-resolution temperature data using SRCNN. To evaluate the super-resolution temperature data, the temperature for a non-observation point is obtained by using the inverse distance weighting method, and the super-resolution temperature data using interpolation is compared with the super-resolution temperature data using SRCNN. We construct an SRCNN model suitable for super-resolution of temperature data and perform super-resolution of temperature data. As a result, the prediction performance of the super-resolution temperature data using SRCNN was about 10.8% higher than that using interpolation.