• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1260-1264
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• 2009

Precipitation time series is a mixture of complicate fluctuation and changes. The monthly precipitation data of 61 stations during 36 years (1973-2008) in Korea are comprehensively analyzed using the EOFs technique and CSEOFs technique respectively. The main motivation for employing this technique in the present study is to investigate the physical processes associated with the evolution of the precipitation from observation data. The twenty-five leading EOF modes account for 98.05% of the total monthly variance, and the first two modes account for 83.68% of total variation. The first mode exhibits traditional spatial pattern with annual cycle of corresponding PC time series and second mode shows strong North South gradient. In CSEOF analysis, the twenty-five leading CSEOF modes account for 98.58% of the total monthly variance, and the first two modes account for 78.69% of total variation, these first two patterns' spatial distribution show monthly spatial variation. The corresponding mode's PC time series reveals the annual cycle on a monthly time scale and long-term fluctuation and first mode's PC time series shows increasing linear trend which represents that spatial and temporal variability of first mode pattern has strengthened. Compared with the EOFs analysis, the CSEOFs analysis preferably exhibits the spatial distribution and temporal evolution characteristics and variability of Korean historical precipitation.

• Current Optics and Photonics
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• 제8권3호
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• pp.307-312
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• 2024

Measuring the three-dimensional (3D) spatial light intensity distribution of an autostereoscopic multiview 3D display at the user position is time-consuming, as luminance has to be measured at different positions around the user position. This study investigates a method to quickly estimate the 3D distribution at the user position. For this purpose, a measurement setup using a white semitransparent diffusing screen or a two-dimensional (2D) spatial sensor was devised to measure the 2D light intensity distribution at the user position. Furthermore, the 3D spatial light intensity distribution at the user position was estimated from these 2D distributions at different viewing distances. From the estimated 3D distribution, the characteristics of autostereoscopic 3D display performance can be derived and the candidate positions for further accurate measurement can be quickly determined.

• 환경영향평가
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• 제22권5호
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• pp.513-523
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• 2013

This purpose of this work is to explore the characteristics of urban thermal environment distribution with the case of Daejeon. To do that, this work applied GIS Spatial Statistics to the LandSAT images gathered from 2000 to 2011. The urban thermal environment distribution at the time point of 2 showed high spatial autocorrelation. Therefore, it is judged that spatial autocorrelation is needed to increase the reliability and explanatory power of the characteristics of thermal environment distribution. In the case of the thermal in Daejeon, its positive clustering appeared high at the time point of 2, and its clustering in 2011 more gradually decreased than that in 2000 to 2011. In particular, given the decrease in the core H-H region, it was found that the thermal environment of Daejeon was greatly improved. However, since the rise in the region L-L means another changed like construction of a new city, it is judged that it is necessary to come up with a proper plan. It is considered that this analysis of the characteristics of urban thermal environment distribution in consideration of spatial autocorrelation L-L be useful for providing a fundamental material necessary for the policy and project of thermal environment improvement.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.578-597
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• 2014

Understanding of 'spatial' pressure distribution is required to determine design loads on local structures, such as plating and framing. However, obtaining a practical 'spatial' pressure distribution is a hard task due to the sensitivity of the data acquisition frequency and resolution. High-resolution Pessure-Idicating Flm (PIF) was applied to obtain pressure distribution and pressure magnitude using stepped crushing method. Different types of PIF were stacked at each test to creating a pressure distribution plot at specific time steps. Two different concepts of plotting 'spatial' pressure-area curve was introduced and evaluated. Diverse unit pixel size was chosen to investigate the effect of the resolution in data analysis. Activated area was not significantly affected by unit pixel size; however, total force was highly sensitive.

• 한국측량학회지
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• 제32권6호
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• pp.571-580
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• 2014

To address unsolved issues of change detection in animated choropleth maps, we proposed the concept of 'gross change detection' and performed an experiment that empirically verifies the incidence of change blindness stems from the 'magnitude of change (MOC)', spatial distribution in animated choropleth maps. We generated experimental materials using the change-characterization arrays and the global Moran's I. Participants had 108 cases of changing maps with time duration (1 to 3 sec) and had questions. The results showed that MOC and duration affect gross change detection, but the most interesting result from our experiment was that different spatial distributions between two adjacent choropleth maps may lead the map reader to under- or over-estimate the level of gross change in the map. It implies that we should consider spatial distribution of change when we design animated choropleth maps.

• 한국컴퓨터정보학회논문지
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• 제24권8호
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• pp.137-142
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• 2019

This paper proposed bitmap based spatial data transmission scheme in need of rapid transmission through network in mobile environment that use and creation of data are frequently happen. Former researches that used clustering algorithms, focused on providing service using spatial data can cause delay since it doesn't consider the transmission speed. This paper guaranteed rapid service for user by convert spatial data to bit, leads to more transmission of bit of MTU, the maximum transmission unit. In the experiment, we compared arithmetically default data composed of 16 byte and spatial data converted to bitmap and for simulation, we created virtual data and compared its network transmission speed and conversion time. Virtual data created as standard normal distribution and skewed distribution to compare difference of reading time. The experiment showed that converted bitmap and network transmission are 2.5 and 8 times faster for each.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.33-36
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• 2007

Acoustic holography exhibits the spatial distribution of sound pressure in time or frequency domain. The obtained picture often contains far more than what we need in practice. For example, when we need to know only the locations and overall propagation pattern of sound sources, a method to show only what we need has to be introduced. One way of obtaining the necessary information is to use envelope in space. The spatial envelope is a spatially slowly-varying amplitude of acoustic waves which contains the information of sources' location. A spatial modulation method has been theoretically developed to get a spatial envelope. By applying the spatial envelope, not only the necessary information is obtained but also computation time is reduced during the process of holography. The spatial envelope is verified as an effective visualization scheme in time domain by being applied to complicated sound fields.

• 지적과 국토정보
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• 제46권2호
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• pp.269-281
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• 2016

최근 공간 정보 분야에서 소셜 미디어와 같은 공간 빅 데이터의 분석과 처리에 많은 관심이 집중되고 있다. 본 연구에서는 공간 빅 데이터 분석의 한 사례로서 트윗 데이터가 가지고 있는 위치 정보와 시간 정보를 바탕으로 시간대별로 공간분포를 분석하고 그 특성을 파악하였다. 부산시 지역의 트윗 데이터를 수집하고, 시간대별 공간분석을 통하여 그 특성을 파악하여, 그 지역의 토지이용 특성과 비교하였다. 부산시 지역의 트윗 데이터를 시간대에 따라 평일 주간, 평일 야간, 휴일 주간, 휴일 야간으로 구분하고, 각 시간대별로 공간적 분포 특성을 파악하여, 공간적으로 집중된 지역의 토지이용 특성과 비교하였다. 본 연구의 결과 트윗 데이터는 시간대에 따라 공간분포가 다르게 나타나고 있으며, 이는 그 지역의 일상생활 패턴과 토지이용 특성을 어느 정도 반영하고 있었다. 본 연구에서는 공간정보 분야에서 트윗 데이터와 같은 소셜 미디어 자료의 분석을 통한 활용 가능성을 제시하였다. 향후 토지 계획이나 도시 계획 등의 분야에서 다양한 소셜 미디어 자료를 활용할 수 있을 것으로 전망된다.

• Spatial Information Research
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• 제13권3호
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• pp.253-260
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• 2005

본 연구의 목적은 GIS기술을 이용하여 적조의 시공간적인 분포를 분석하는 것이다. 적조에 의해 발생하는 피해는 적조 생물종에 따라 다양하게 나타난다 때문에 적조의 피해를 저감하기 위해서는 시-공간적인 적조 생물종의 분포특성을 파악하는 것이 중요하다. 이러한 관점에서 우리는 최초의 적조발생지역, 공간적 발생빈도, 적조의 이동 등을 분석하였다. 본 연구에서 사용된 공간자료는 적조 속보 보고에 의해 공간분포를 디지타이징하였고, 적조데이터베이스를 구축하기 위해 적조 생물종, 생물 밀도, 수온 등의 다양한 속성자료를 구성하였다. 적조의 시-공간적 분포 특성을 분석하기 위해 다양한 공간분석기법을 적용하였다. 이러한 공간분석 결과로부터 남해에서의 시-공간 적이 적조 공간 정보를 얻을 수 있었다.

• Geomechanics and Engineering
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• 제25권2호
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• pp.135-142
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• 2021

This study provided a new research perspective for processing and analyzing AE data to evaluate rock failure. Cluster method and information entropy theory were introduced to investigate temporal and spatial correlation of acoustic emission (AE) events during the rock failure process. Laboratory experiments of granite subjected to compression were carried out, accompanied by real-time acoustic emission monitoring. The cumulative length and dip angle curves of single links were fitted by different distribution models and distribution functions of link length and directionality were determined. Spatial scale and directionality of AE event distribution, which are characterized by two parameters, i.e., spatial correlation length and spatial correlation directionality, were studied with the normalized applied stress. The entropies of link length and link directionality were also discussed. The results show that the distribution of accumulative link length and directionality obeys Weibull distribution. Spatial correlation length shows an upward trend preceding rock failure, while there are no remarkable upward or downward trends in spatial correlation directionality. There are obvious downward trends in entropies of link length and directionality. This research could enrich mathematical methods for processing AE data and facilitate the early-warning of rock failure-related geological disasters.