• Journal of the Korean association of regional geographers
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• v.22 no.2
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• pp.424-438
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• 2016

In an effort to prevent urban decline and hollowing-out phenomenon and to vitalize stagnant local economy, a new urban regeneration paradigm is on the rise. This study aims to analyze urban decline characteristics using the spatial statistical method and GIS on the basis of decline standards in the Urban Regeneration Special Act, and spatial autocorrelation technique. The Gwangju Metropolitan City was set as a research target, and the decline standards in the Urban Regeneration Special Act - population reduction, business declines, and outworn buildings - were applied as the indicator to secure the objectivity. In particular, this study has a distinctive feature from the other existing ones, as applying GIS and the spatial statistical technique, in a sense to make urban decline characteristics analysis by the spatial autocorrelation technique. The overall analysis procedure was carried out by applying the standards of designating urban regeneration regions, and following the spatial exploratory procedure step by step. Therefore, the spatial statistical method procedure and the urban decline characteristics analysis data being presented in this study, as the results, are expected to contribute to the urban decline diagnosis at the level of metropolitan city, as well as to provide useful information for spatial decision making in accordance with urban regeneration.

• Journal of KIISE:Software and Applications
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• v.33 no.6
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• pp.574-579
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• 2006

The feature selection algorithms should broadly and efficiently explore the huge problem spaces to find a good solution. This paper attempts to gain insights on the fitness landscape of the spaces and to improve search capability of the algorithms. We investigate the solution spaces in terms of statistics on local maxima and minima. We also analyze behaviors of the existing algorithms and improve their solutions.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.206-212
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• 2007

웹을 기반으로 하는 e-러닝에 대한 교육적 수요는 증가하고 있다. 이와 동시에, 학습 공간으로서의 사이버 공간의 활용에 대한 고민도 증가하였다. 전통적인 학습활동을 사이버 공간에 복제하려 했던 고전적 방식이 e-러닝 또는 사이버 학습이 아니라는 사실을 확인하기 시작했기 때문이다. e-러닝의 가치가 강조됨에도 불구하고, 실제 사이버 공간에서 일어나는 학습자의 특성과 학습활동이 구체적으로 어떻게 일어나는 지에 대한 탐색은 미흡하다. 산재한 정보를 스스로 가공한 지식, '학습하는 방법을 학습'하는 것이라는 개념들이 제시됨에도 불구하고, 사이버 공간에 산재한 정보, 학습하는 방법의 학습, 그리고 사이버 공간의 학습특성에 대한 논란은 여전하다. 본 연구에서는 실제 사이버 학습 사이트를 이용하고 있는 학습자들의 행동을 중심으로, 학습자의 특성을 탐색하였다. 사이버 공간에서 보이는 스스로 학습하는 방법이 무엇인지 확인하고 이것이 다양한 학습자 유형으로 구분되는 지를 확인하고자 하였다. 연구대상이 된 사이버 학습 사이트는 서울, 부산, 대구, 광주 교육청에서 운영하는 사이버 가정 학습관이었다. 총 1535명의 사이버 가정 학습관 이용자들의 특성이 분석되었다. 사이버 가정학습관 이용자들의 행동특성은 9개의 요인-놀이 활동, 공동 경험, 현실 정체, 공동 성취, 개인주의, 경쟁 지향, 성취감, 편리성(조작 용이), 생생함-으로 구분되었다. 9개의 활동 요인을 기준으로 하여 확인된 학습자 유형은 4가지로 나타났다. 4가지 학습자 유형은 각각 독야청청형, 동고동락형, 의무방어형, 희희낙낙형으로 명명되었다. 이들 유형은 학습 활동 정도 및 사이트 이용 행동, 학습 스타일(사이버 학습 활동 양식)에서 서로 차이가 있었다. 본 연구는 기존의 이론적인 모델에 기초하여 임의적으로 구분된 사이버 학습자 유형 구분이 아닌, 실제 학습 활동을 탐색하였다는 측면에서 의미가 있다. 특히, 기존의 오프라인 학습 이론 및 학습자 특성 연구를 사이버 학습에 그대로 적용할 것이 아니라 사이버 공간의 특성이 실제 학습 활동에서 어떻게 나타났는지를 밝히려고 했다는데 그 의의가 있다. 향후, 사이버 학습자 유형에 따른, 사이버 학습활동의 촉진방안이나 학습 효과의 차이를 높일 수 있는 구체적인 학습 시스템의 설계 및 운영 모델에 대한 탐색이 필요할 것이다.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.459-466
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• 2002

Modern embedded system employs a hybrid architecture which contains a general micro processor and reconfigurable devices such as FPGAS to retain flexibility and to meet timing constraints. It is a hard and important problem for embedded system designers to explore and find a right system configuration, which is known as design space exploration (DSE). With DES, it is possible to predict a final system configuration during the design phase before physical implementation. In this paper, we implement a timing analysis simulator for a DSE on a hybrid embedded system. The simulator, integrating exiting timing analysis tools for hardware and software, is designed by extending Y-chart approach, which allows quantitative performance analysis by varying design parameters. This timing analysis simulator is expected to reduce design time and costs and be used as a core module of a DSE for a hybrid embedded system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2256-2262
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• 2015

Recently, device-to-device (D2D) communication has been considered as key technology for future cellular system, because it can solve the problem of excessive data traffic increment and can also provide new communication services. Herein, we propose new neighbor discovery for D2D communication and examine its performance. Our proposed scheme is proximity beacon based discovery in which wireless resource for pilot transmission is assigned based on the spatial correlation of wireless channel and sensing period is adjusted according to target accuracy such that power consumption can be reduced. The performance of our propose scheme is analyzed mathematically and verified through computer simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5015-5022
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• 2010

Most of the existing pattern mining techniques are capable of searching patterns according to the continuous change of the spatial information of an object but there is no constraint on the spatial information that must be included in the extracted pattern. Thus, the existing techniques are not applicable to the optimal path search between specific nodes or path prediction considering the nodes that a moving object is required to round during a unit time. In this paper, the precision of the path search according to the spatial hierarchy is analyzed using the Spatial-Temporal Optimal Moving Pattern(with Frequency & Weight) (STOPM(FW)) algorithm which searches for the optimal moving path by considering the most frequent pattern and other weighted factors such as time and cost. The result of analysis shows that the database retrieval time is minimized through the reduction of retrieval range applying with the spatial constraints. Also, the optimal moving pattern is efficiently obtained by considering whether the moving pattern is included in each hierarchical spatial scope of the spatial hierarchy or not.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.632-647
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• 2007

Lots of geographic phenomena have dynamic spatial patterns with time changes, and there have been lots of researches on exploring these dynamic spatial patterns. However, most of these researches focused on the static pattern analysis in a given period, rather than dealing with dynamic changes in the spatial pattern over time with the continual or cumulative perspective. For this reason, investigation of the inertia of spatial process in terms of temporal changes is needed. From this background, the purpose of this paper is to propose the methodology to explore the changes in spatial pattern cumulatively by considering the inertia of the spatial statistics over time, and to apply it to the case study That is, we introduce the new spatial statistic, and produce the z-values of the statistic using Monte Carlo Simulation, and then to explore the changes in spatial patterns over time cumulatively. To do this, the method to combine the J statistic with CUSUM statistic for exploring spatial patterns, and to apply it to the changes in the commercial landuse in Erie County, New York State. Through the proposed method for spatio-temporal Patterns, we could explore continual changes effectively in the spatial patterns reflecting the statistics by temporal spot cumulatively.

• Journal of the Korean Geographical Society
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• v.47 no.2
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• pp.268-281
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• 2012

In spite of the usefulness of migration statistics in spatially understanding social processes and identifying social effects of spatial processes, services and analyses of the statistics have been restricted due to the complexity of their data structure. In addition, flow mapping functionality which is a useful method to explore and visualize the migration statistics has yet to be fully represented in modern GIS applications. Given this, the purpose of this research is to demonstrate the possibility of flow mapping and the exploratory spatial analysis of the migration statistics in a Web GIS environment. For this, the characteristics of the statistics were examined from database, GIS, and cartographic perspectives. Then, O-D structure of the migration statistics was converted to spatial data appropriate to f low mapping based on the characteristics. The interface of Web GIS is specialized the migration statistics and provides exploratory visualization by allowing dynamic interactions such as spatial focusing and attribute filtering.

• Journal of Intelligence and Information Systems
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• v.11 no.1
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• pp.153-167
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• 2005

In this paper, we consider the problem of exploring unknown environments with a mobile robot or an autonomous character agent. Traditionally, research efforts to address the space exploration problem havefocused on the graph-based space representations and the graph search algorithms. Recently EXPLORE, one of the most efficient search algorithms, has been discovered. It traverses at most min$min(mn, d^2+m)$ edges where d is the deficiency of a edges and n is the number of edges and n is the number of vertices. In this paper, we propose DFS-RTA* and DFS-PHA*, two real-time graph search algorithms for directing an autonomous agent to explore in an unknown space. These algorithms are all built upon the simple depth-first search (DFS) like EXPLORE. However, they adopt different real-time shortest path-finding methods for fast backtracking to the latest node, RTA* and PHA*, respectively. Through some experiments using Unreal Tournament, a 3D online game environment, and KGBot, an intelligent character agent, we analyze completeness and efficiency of two algorithms.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.18-29
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• 2022

The purpose of this study is to examine the spatial characteristics and factors in the occurrence of COVID-19 from January 20 to August 30 of 2020. The exploratory spatial data analysis and spatial econometrics model are used. The spatial unit of analysis is 255 si-gun-gu in Korea. As a result of the analysis, COVID-19 infection did not appear to be a significant factors(host and environment) influencing the emergence of existing new infectious diseases, but there was a relationship between spatially adjacent areas and their occurrence. It also showed a close relationship with the outbreak pattern of group 4 infectious diseases, another type of new infectious disease in Korea. The result of this study shows that COVID-19 is not a new pattern of emerging infectious diseases. It means that the properties of the space where new infectious diseases appear must be continuously managed in order to effectively control new infectious diseases.