• Journal of Information Technology Applications and Management
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• 제12권1호
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• pp.35-48
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• 2005

An architectural framework is developed for integrating geospatial and temporal data with relational information from which a spatio-temporal data warehouse (STDW) system is built. In order to implement the STDW, a generic conceptual model was designed that accommodated six dimensions: spatial (map object), temporal (time), agent (contractor), management (e.g. planting) and tree species (specific species) that addressed the 'where', 'when', 'who', 'what', 'why' and 'how' (5W1H) of the STDW information, respectively. A formal algebraic notation was developed based on a triplet schema that corresponded with spatial, temporal, and relational data type objects. Spatial object structures and spatial operators (spatial selection, spatial projection, and spatial join) were defined and incorporated along with other database operators having interfaces via the generic model.

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

• Spatial Information Research
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• 제10권4호
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• pp.515-532
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• 2002

Planning Support System (PSS), an alternative framework of computer-aided planning system combining geographic information system (GIS), urban models, and visualization tools, has been actively researched and applied in many developed countries. This paper introduces a PSS-based land use change model, What if\ulcorner PSS, by applying it to Chongju City, Korea. This model application study used the spatial database, Restricted Development Zone (RDZ), and other hypothetical land supply- and demand-related policies of Chongju City. The collaborative PSS model supported land use planning process by helping users to speedily and easily create and test policy-oriented scenarios. The study found that the fully operational PSS model was readily applicable and useful to Korean local land use planning. The paper discusses the conceptual model framework, data requirement, application process, model output, and practical usage. This study would be considered as a prototypical approach of PSS-based land use plan making for Korean cities.

• 교육녹색환경연구
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• 제5권2호
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• pp.1-13
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• 2006

The purpose of this study is to clarify the actual conditions of spatial composition of educational facilities by design process model. This article discuses about the characteristics of the floor plan composition and the site plan patterns of 49 middle and high schools in gyeongnam province. The results of this study are summarized as follows; 1) Comparing to traditional middle and high school facilities, it occurs various types of plane and the area is somewhat expanded in the school with same class size, however, it needs to improve facility standards in its reality to deal with the change of future educational environment actively. 2) Spatial composition of educational facilities should functionally designed considering that the characteristics of design process model. In facilities arrangement of middle and high schools, it shows diverse forms of arrangement from existing uniform straight type, however, most of schools do not being against the simple in their external space. Therefore, it requires an expansion of space siæ and facilities for the change of school life outside class.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.391-393
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• 2006

In this study, the performance of artificial neural network (ANN) models for estimating spatial distribution of water quality was evaluated using electric conductivity (EC) values in landfill site. For the ANN model development, feedforward neural networks and backpropagation algorithm with gradient descent method were used. In Test 1, the interpolation ability of the ANN model was evaluated. Results of the ANN model were more precise than those of the Kriging model. In Test 2, spatial distributions of EC values were predicted using precipitation data. Results seemed to be reasonable, however, they showed a limitation of ANN models in extrapolations.

• Spatial Information Research
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• 제14권3호
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• pp.321-334
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• 2006

3차원 공간정보는 2차원에 비해 공간적 현실감이 뛰어나기 때문에 최근 경관분석, 도시계획 및 웹(Web)을 통한 지도 서비스 분야 등에서 이에 대한 관심이 증가하고 있다. 3차원 공간 정보는 기하학적 특성상 2차원 공간정보에 비해 데이터 양이 크다. 그러므로 데이터 전송과 시각화를 위한 보다 효율적인 방법이 필요하다. 시각화 분야에서 이미 많은 연구가 진척된 세밀도 개념은 이를 해결하기 위한 효과적인 방법이다. 본 연구에서는 국제 표준 공간 데이터 모델을 기반으로 데이터 전송에 있어서 효율적인 두 가지 세밀도 모델을 제시한다 첫 번째는 객체 단위에 세밀도 단계를 부여하는 객체단위세밀도 모델이고, 두 번째는 객체를 이루는 구성요소에 세밀도 단계를 부여하는 요소선택세밀도 모델이다. 본 논문에서는 제시된 위 두 가지 세밀도 모델을 이용하여 데이터 전송의 효율성을 비교해 보았다.

• 한국환경과학회지
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• 제27권7호
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• pp.499-507
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• 2018

Agricultural meteorological information is an important resource that affects farmers' income, food security, and agricultural conditions. Thus, such data are used in various fields that are responsible for planning, enforcing, and evaluating agricultural policies. The meteorological information obtained from automatic weather observation systems operated by rural development agencies contains missing values owing to temporary mechanical or communication deficiencies. It is known that missing values lead to reduction in the reliability and validity of the model. In this study, the hierarchical Bayesian spatio-temporal model suggests replacements for missing values because the meteorological information includes spatio-temporal correlation. The prior distribution is very important in the Bayesian approach. However, we found a problem where the spatial decay parameter was not converged through the trace plot. A suitable spatial decay parameter, estimated on the bias of root-mean-square error (RMSE), which was determined to be the difference between the predicted and observed values. The latitude, longitude, and altitude were considered as covariates. The estimated spatial decay parameters were 0.041 and 0.039, for the spatio-temporal model with latitude and longitude and for latitude, longitude, and altitude, respectively. The posterior distributions were stable after the spatial decay parameter was fixed. root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and bias were calculated for model validation. Finally, the missing values were generated using the independent Gaussian process model.

• 한국정보과학회논문지:소프트웨어및응용
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• 제37권3호
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• pp.194-204
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• 2010

실세계의 공간이나 이에 대응되는 가상세계의 공간은 공간의 일부인 지역(region)들과 그것들을 차지하고 있는 물리적 객체(physical object)들로 구성되어 있다. 이러한 공간 구성요소들간의 공간관계의 표현의 실제와의 부합성과 다양성은 이러한 공간에서 활동하는 에이전트의 공간관계 추론이나 이벤트(event)의 전개의 사설성과 정교함의 바탕이 된다. GIS나 AI 분야에서 연구되고 있는 기존의 공간관계 모델들은 객체의 규모에 따라 이원화된 영역에 적절한 모델들이거나 제한된 위상관계만 표현할 수 있기 때문에 다양한 지역과 객체를 가진 일반적 공간의 통합적 표현에는 부적합하다. 본 연구에서 개발될 공간표현 모델은, 첫째 대규모 공간과 소규모 공간 관계에 통합적으로 적용가능한 계층구조를 바탕으로 구성한다. 둘째, 소규모 객체들간에도 disjoint나 touch와 같이 제한된 위상 공간관계(topological relations)만이 아닌 접촉관계와 구성요소객체들의 조합을 바탕으로 하여 충분히 다양한 공간관계를 표현할 수 있도록 세분화한다. 셋째, solid object에 대비되는 container성질을 추가하고 중력 방향을 고려하여 공간관계를 추가로 다양화한다. 본 연구의 결과인 중력의 영향을 고려한 통합적 공간관계 모델은 컴퓨터상에서 실세계와 유사한 복잡한 가상공간을 공간적 사건들과 연관지어 정밀하게 시뮬레이션할 수 있게 하고 가상공간에서 에이전트들이 행동을 할 때 공간적 측면의 상황판단을 할 수 있도록 가상공간에 대한 에이전트들의 공간적 지식을 표현하는 수단을 제공한다.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.385-400
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• 2009

The adverse effect of harmful plankton on the marine ecosystem is a topic of deep concern. To investigate the role of such phytoplankton, a mathematical model containing distinct dynamical equations for toxic and non-toxic phytoplankton is analyzed. Stability analysis of the resulting three equation model is carried out. A continuous time variation in toxin liberation process is incorporated into the model and a stability analysis of the resulting delay model is performed. The distributed delay model is then extended to include the spatial distribution of plankton and the delay-diffusion model is analyzed with spatial and spatiotemporal kernels. Conditions for diffusion-driven instability in both the cases are derived and compared to explore the significance of these kernels. Numerical studies are performed to justify analytical findings.

• Spatial Information Research
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• 제13권3호
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• pp.239-252
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• 2005

본 연구는 대용량의 공간자료에서 의미 있는 지식을 탐색 및 발견하고, 인터넷 환경에서 공간적 의사결정과정을 지원하기 위한 방안을 설계하였다. 그리고 설계를 기반으로 실험적 원형 시스템(Pilot Tested System)을 구현하여 의사결정자와 분석가 사이에서 특정주제에 적합한 다차원적 분석을 위해 양방향 통신이 가능하도록 공간 데이터 웨어하우스의 눈송이 스키마모델(snowflake schema model)을 활용하였다. 눈송이 스키마는 공간자료와 연계할 경우 기존 스타 스키마모델(star schema model)보다 확장성과 유연성이 뛰어난 분석중심의 설계방안이다. 또한 눈송이 스키마모델의 평가를 위해 백화점 거래사례를 통해 실험적 시스템을 구현하여 평가하였다. 이 시스템의 목적은 목표마케팅 지역설정이며, 의사결정자와 분석가의 양방향통신이 가능한 인터넷상담시스템이다.