시간지리학 응용을 위한 시공간데이터베이스 기반의 GIS 컴퓨팅 연구

박기호,이양원,안재성,Park Key-Ho,Lee Yang-Won,Ahn Jae-Seong 한국공간정보학회 2005 한국공간정보학회지 Vol.13 No.3

This study attempts at building a GIS computing environment that incorporates object-relational spatio-temporal database for the time geography model with space-time path, space-time prism and space-time accessibility. The proposed computing environment is composed of ( i ) mobile GIS application for collecting spatio-temporal trajectory data of an individual, ( ii ) spatio-temporal database server that includes time geography model, and (iii) geovisualization client that performs time geographic queries to the spatio-temporal database. The spatio-temporal trajectory data collected by GPS-PDA client is automatically processed and sent to server through data management middleware. The spatio-temporal database implemented by extending a generic DBMS provides spatio-temporal objects, functions, and SQL. The geovisualization client illustrates 3D visual results of the queries about space-time path, space-time prism, and space-time accessibility. This study confirms the possibility of integrating mobile GIS and DBMS for time geography model, and it presents the appropriate database model with spatio-temporal objects and functions that may handle very large data for time geography application.

근린가중치행렬이 공간적 자기상관 추정에 미치는 영향

박기호(Key-Ho Park) 서울연구원 2004 서울도시연구 Vol.5 No.3

시공간 개인통행자료의 지리적 시각화

박기호(Key-Ho Park),안재성(Jae-Seong Ahn),이양원(Yang-Won Lee) 대한지리학회 2005 대한지리학회지 Vol.40 No.3

이 연구는 GPS 수신기를 통해 수집된 개인통행자료를 이용하여 통행패턴의 시공간적 특성을 다양한 그래픽으로 요약하고 탐색적 분석을 가능케하는 지리적 시각화 환경을 제안하고 이를 구현 및 평가하는 것을 목적으로 한다. 이 연구에서는 시공간입방체(space-time cube)를 바탕으로 시간지리학 개념을 시각적으로 표현하였으며, 시간산포기둥(temporal dispersion cylinder), 평행평면그림(parallel plane plot)과 같은 부가적인 시각화 도구의 구현을 통해 개인통행패턴의 시공간적 속성 및 이동경로 주위지역의 사회경제적·자연적 속성을 함께 탐색할 수 있도록 하였다. 또한 사용자와의 상호작용을 통해 개인통행자료에 포함되어 있는“언제”, “어디에서”, “무엇을”이라는 세 가지 정보요소들을 동적으로 탐색 및 질의할 수 있는 환경을 제공한다. This study attempts at prototyping and evaluating a geovisualization tool that summarizes and explores human activity patterns using spatio-temporal trajectory data collected from GPS receiver. A set of core conceptualization developed in “time geography” is successfully represented by our prototype based on the notion of “space-time cube.” The notions of “temporal dispersion cylinder” and “parallel plane plot” are also implemented to allow further analyses of human activity pattern on the space-time trajectory. The capabilities of the geovisualization environment we proposed include the interactive and dynamic functions that support a variety of explorations on the three components of spatio-temporal data : space(where), time(when), and object(what).

거리척도와 앙상블 기법을 활용한 지가 추정

이창로,박기호,Lee, Chang-Ro,Park, Key-Ho 한국국토정보공사 공간정보연구원 2016 지적과 국토정보 Vol.46 No.2

This study estimated land prices using instance-based learning. A k-nearest neighbor method was utilized among various instance-based learning methods, and the 10 distance metrics including Euclidean distance were calculated in k-nearest neighbor estimation. One distance metric prediction which shows the best predictive performance would be normally chosen as final estimate out of 10 distance metric predictions. In contrast to this practice, an ensemble technique which combines multiple predictions to obtain better performance was applied in this study. We applied the gradient boosting algorithm, a sort of residual-fitting model to our data in ensemble combining. Sales price data of farm lands in Haenam-gun, Jeolla Province were used to demonstrate advantages of instance-based learning as well as an ensemble technique. The result showed that the ensemble prediction was more accurate than previous 10 distance metric predictions.

지역분석을 위한 시계열 공간연관성 탐색도구

안재성,박기호,이양원,Ahn Jae-Seong,Park Key-Ho,Lee Yang-Won 한국공간정보학회 2006 한국공간정보학회지 Vol.14 No.1

The concept of 'spatial association' explains spatial distribution pattern of geographical phenomenon based on similarity with neighborhoods, as in the Tobler's Law of Geography: 'Everything is related to everything else, but near things are more related than distant things.' In this study, we develop a time-series exploratory analysis tool for discovering temporal patterns of spatial association by combining spatial statistics and geo-visualization, and thus present a possibility to support spatial decision-making process. As for the spatial proximity weight matrix indispensable to measuring global and local spatial association, we employ a variety of flexible weighting schemes using geometric characteristics of areal unit. In addition, we renovate the existing visualization methods for more effective understanding of the procedures and results of time-series analysis on spatial association: for instance, temporal parallel coordinate plot with box plot, animated map for spatial association, and 3D Moran scatterplot. The feasibility of our system is verified by time-series analysis experiments on the spatial association of land price fluctuation rate for all administrative units in Korea, $1995{\sim}2004$.

지도사용의 인지적 효과 측정에 관한 연구

조현정,신휴석,박기호,Cho, Hyun-Jeong,Shin, Hyu-Seok,Park, Key-Ho 대한공간정보학회 2012 한국공간정보학회지 Vol.20 No.5

The purpose of this study was to establish an analytical framework and quantitative methodologies to analyze 'the cognitive effects of web map use' and to empirically test it. This experimental design was established based on the literature about spatial cognition. Accuracy, reaction time, and confidence within each participant were compared to measure the cognitive effects of web map use for wayfinding. Geometric accuracy of the cognitive maps was estimated and calculated based on the bidimensional regression. The experimental results showed that characteristics of map users and repetition of map use rather than types of map representation did significantly affect accuracy and reaction time of spatial cognition by using web maps. And confidence appeared to be low when the participants referred to both 2D and 3D maps for wayfinding tasks on the web maps. Understanding spatial cognition of web map users, which was suggested in the study, will help cartographers make more effectively-communicated maps.

크리깅을 이용한 소나무림 지위지수 공간분포 추정

김경민 ( Kyoung Min Kim ),박기호 ( Key Ho Park ) 한국산림과학회 2013 한국산림과학회지 Vol.102 No.4

Site index information given from forest site map only exist in the sampled locations. In this study, site index for unsampled locations were estimated using kriging interpolation method which can interpolate values between point samples to generate a continuous surface. Site index of Pinus densiplora in Danyang area were calculated using Chapman-Richards model by plot unit. Then site index for unsampled locations were interpolated by theoretical variogram models and ordinary kriging. Also in order to assess parameter selection, cross-validation was performed by calculating mean error (ME), average standard error (ASE) and root mean square error (RMSE). In result, gaussian model was excluded because of the biggest relative nugget (37.40%). Then spherical model (16.80%) and exponential model (8.77%) were selected. Site index estimates of Pinus densiplora throughout the entire area in Danyang showed 4.39~19.53 based on exponential model, and 4.54~19.23 based on spherical model. By cross-validation, RMSE had almost no difference. But ME and ASE from spherical model were slightly lower than exponential model. Therefore site index prediction map from spherical model were finally selected. Average site index from site prediction map was 10.78. It can be expected that regional variance can be considered by site index prediction map in order to estimate forest biomass which has big spatial variance and eventually it is helpful to improve an accuracy of forest carbon estimation.

국토 공중모니터링 현황과 발전방향

신휴석,박충기,김연미,황선영,박기호,Shin, Hyu-Seok,Park, Chung-Ki,Kim, Yeon-Mi,Hwang, Sun-Young,Park, Key-Ho 한국공간정보학회 2008 한국공간정보학회지 Vol.16 No.2

Recent climate fluctuation and environmental change at global scale are causing more incidences of disasters and calamities over the world. In a response to this environmental crisis, international collaboration for Earth Observation(EO) is obtaining more significance in order to understand, watch, and forecast changes in the earth system. As such, aerial monitoring based on remotely sensed data, indispensable for EO, is also drawing more attentions. In this context, we discuss diverse aspects of future developments in the Korean domestic system for aerial monitoring. This paper first thoroughly examines current status of national and international collaboration system arid research of aerial monitoring. It then suggests specific development plans for four critical dimensions such as research, organization, institutional systems, and strategies. Our study would facilitate systematically establishing policies for aerial monitoring in Korea and creating a domestic GEOSS(Global Earth Observation System of Systems) in the near future.

크리깅 기법을 이용한 단양군의 산림 탄소저장량 추정 -지상부 바이오매스를 대상으로-

박현주 ( Hyun Ju Park ),신휴석 ( Hyu Seok Shin ),노영희 ( Young Hee Roh ),김경민 ( Kyoung-min Kim ),박기호 ( Key Ho Park ) 한국지리정보학회 2012 한국지리정보학회지 Vol.15 No.1

The aim of this study is to estimate aboveground biomass carbon stocks using ordinary kriging(OK) which is the most commonly used type of kriging and regression kriging(RK) that combines a regression of the auxiliary variables with simple kriging. The analysis results shows that the forest carbon stock in Danyang is estimated at 3,459,902 tonC with OK and 3,384,581 tonC with RK in which the R-square value of the regression model is 0.1033. The result of RK conducted with sample plots stratified by forest type(deciduous, conifer and mixed) shows the lowest estimated value of 3,336,206 tonC and R-square value(0.35 and 0.18 respectively) is higher than that of when all sample plots used. The result of leave-one-out cross validation of each method indicates that RK with all sample plots reached the smallest root mean square error(RMSE) value(22.32 ton/ha) but the difference between the methods(0.23 ton/ha) is not significant.

HTML5 Canvas를 활용한 시각적 공간분석 환경의 설계와 구현

박미라 ( Mi Ra Park ),박기호 ( Key Ho Park ),안재성 ( Jae Seong Ahn ) 한국지리정보학회 2011 한국지리정보학회지 Vol.14 No.4

This study designed and implemented a web-based computing environment for geovisual analytics using HTML5 canvas. The computing environment supports visualization tools and user`s interaction. The visualization tools are cluster map, animated map, temporal parallel coordinate plot, and temporal heat map chart. Users can explore the temporal changes of cluster using multiple view and brushing technique. The computing environment that works well across browsers is used in the computing environment with multiple devices.