• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.3
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• pp.313-321
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• 2002

Supplying high-resolution satellite image, we take much interest in the update and the revision of digital map and thematic map based on the satellite image. This study presented the possibility of the update and the revision to the existing digital map on a scale of l/5,000 and 1/25,000 to take advantage of the IKONOS satellite image. We performed geometric correction to make use of the ground control points of the existing digital map in IKONOS mono-image and created ortho-image by extracting digital elevation model from three dimensional contour data and altitude on the existing digital map. We revised changed features in the method of screen digitizing by overlapping orthorectified satellite image and existing digital map and flawed features of the unchanged area on the satellite images for positional accuracy analysis. As a result, rectification error is calculated at $\pm$3.35m by RMSE. There is a good possibility of update of digital map under the scale of 1/10,000. It is possible to the update of the large scale digital map over the scale of l/5,000, as if we used the method of stereo image and ground control point surveying.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.29-37
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• 2003

The High-resolution satellite images are able to get the latest information of wide range area and to shorten updating cycle of digital map better than the aerial images. Especially, as high-resolution satellite images are opened to public recently and able to be used commercially, the studies that make ortho-images using them and apply to the digital mapping and the database of geo-spatial information system are having been progressed actively. Therefore, the purposes of this study are to establish the auto-extraction methods and to develop algorithms for automatically extracting buildings which are distributed very much in urban areas and which updating cycle needs to shorten, out of man-made structures in the IKONOS ortho-image with 1m spatial resolution. The result of this study, we can extract automatically extract 72% out of the whole buildings. And we could know that the methods and algorithms proposed in this study are good relatively analyzing the error trend by means of the comparison with ortho-image, digital map and hawing result.

• The KIPS Transactions:PartD
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• v.9D no.6
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• pp.1017-1024
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• 2002

According as mobile computing environment is generalized by development of wireless networking technology and communication device, mobile host uses local cache for extensibility and early response time. and reduction of limited bandwidth. This time, between mobile host and mobile support station cache need consistency interested person of done data accordingly much techniqueses propose. Existent consistency techniques because detection based techniqueses are used mainly and broadcast periodic invalid message considering frequent disconnection. However, these techniqueses increase abort step through increase or delay of transmission message number by accuracy examination of data. Therefore, because mobile host deletes cached data, and extensity are decreased. Techniques that is proposed in this paper did to perform refering update frequency about object that page request or when complete update operation happens to solve these problem. Therefore, have advantage that response is fast because could run write intention declaration or update by update frequency electively asynchronously when update operation consists and abort step decreases. Also, improved extensity running delete or propagation electively according to update frequency about periodic invalid message gone since disconnection.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.3
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• pp.19-26
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• 2007

The renewal update of the digital map constructed through NGIS has been conducted for the enhancement of usage, maintenance so that the latest data is guaranteed. The total update has been done every five years for five regions of the country using aerial photographs and satellite images. By launching the third phase of NGIS, the updating plan was changed from total to total or partial update including the real time update scheme. Furthermore, the update period was improved from five to two years and four years for a large and a small city, respectively. Therefore, it is necessary to develope a matching technique which combines various geographic information (such as drawing map, surveying drawing and map) with exact position on the digital map. In this study, we developed a matching algorithm based on central point and suggested a method which uses general surveying drawing for revision/update of the digital map. The general survey is conducted when a civilian development on lands are approved. Thus, the outcome from the survey, which is the general survey drawing, contains the latest various contents such as road, building, water pipe and manhole. A consistent and efficient method using the general survey drawing for near real time update of the digital map by applying the developed matching algorithm is presented.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.153-162
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• 2010

Abies holophylla Maxim. is a shade tolerant species that has potential to be used for continuous cover forestry system. Stand structure and natural regeneration of A. holophylla stands in Yong-In area located in the central part of Korea was investigated to estimate the self sustainability of A. holophylla plantation. Species composition, diameter at breast height (DBH) and height distribution of trees larger than 2 cm DBH were measured in ten stands in three study sites of Jeongsu-ri, Daedae-ri, and Hodong. Species and coverage of shrub layer, and A. holophylla seedlings were also investigated. While A. holophylla in non-managed stands (Jengsuri and Daedae-ri study sites) had the importance value of 40% and showed continuous diameter and age distribution, A. holophylla in Hodong site had narrow bell-shaped DBH distribution mostly concentrating between 25-35 cm DBH classes, and single canopy structure. Abies holophylla stands in Hodong have experienced occasional thinning and selective cutting. The correlation coefficient between age-DBH was significant but low ($R^2$=0.2, P=0.03), and similar aged A. holophylla had diverse DBH values. Continuos DBH distribution and multi-canopy structure of A. holophylla stands in Jeongsu-ri site show that natural regeneration of A. holophylla has been continuously occurred in this area. Seedling density of A. holophylla was between 2000 and 33000/ha, however, the number of trees in 2-5 cm DBH class was only 40-150 trees/ha, implying that the survival rate of seedlings is not high. Continuous natural regeneration and 0.6 cm/year of diameter growth rate of A. holophylla indicate that this area could be an appropriate habitat for this species, and A. holophylla plantation in this region seem to persist suggesting the possibility of managing the stands for continuous cover forestry system as well as selective harvesting practices.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.697-699
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• 2004

오늘날 무선 통신 기술의 급속한 발전과 이동 단말의 소형화, 고성능화가 실현됨에 따라 이동 중 데이터 통신이 가능하도록 하기 위해서는 이동 단말의 이동성을 효율적으로 관리하는 것이 매우 중요하다. 본 논문에서는 IETF에서 개발한 Mobile IPv6를 기반으로 지역적 이동성 기능을 제공하기 위하여 이동 노드의 기능을 강화한 방안을 구현하고 실측을 통하여 성능을 분석하였다. 본 논문에서 구현한 방안은 이동 단말이 외부 도메인 내에서 핸드오프 시 바인딩 메시지를 지역 내에서 처리하여 자신의 위치를 갱신하는 시간을 감소시킴으로써 Mobile IPv6보다 패킷 손실을 줄이고 TCP 처리율을 높임을 알 수 있었다.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.3
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• pp.129-141
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• 2005

It is difficult to edit large-scale digital maps because of problems of cost and process and it is carried out by aerial photogrammetry in renewal periods. Five years of update period cannot provide exact data required in the fast-moving age. This study is to analyze applicability and impact for editing digital map of road system using the GPS-Van. Results are compared with accuracy of the data acquisition with GPS-Van positioning. INS data are affected by the barrier to receive GPS data. But high accuracy were achieved by thorough plans according to work order. By using GPS Van and fieldwork at the same time for editing and renewal of digital map, it is expected that this method can be used to reduce costs in the economic and temporal aspects, and provide rapid and accurate digital map of road system.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.2 s.36
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• pp.43-53
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• 2006

As NGIS project has been implemented in 1995 and effectiveness of geospatial information increased, Digital maps serve several purpose in administrative, living, and the variety of industrial fields. But, Digital maps have difficulties in application of managing urban facilities due to many differences with real world information caused by high update cost and long generation period. This paper suggests an update method of building layers of digital map in urban area; first, we verify the filtered building information using digital areal imagery and LiDAR data which is high-accurate and also can be faster and more economical in 3D information acquisition, and finally update building layers by comparing with the existed digital map. Future research will concentrate on automatic removal of the small and the tree regions, discrimination of buildings and vegetation for generating and updating building layers using LiDAR data.

• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1097-1109
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• 2023

Urban is an area where small-scale changes to individual buildings occur frequently. An existing urban building database requires periodic updating to increase its usability. However, there are limitations in data collection for building changes over a wide urban. In this study, we check the possibility of detecting building changes and updating a building database by using satellite images that can capture a wide urban region by a single image. For this purpose, building areas in a satellite image are first extracted by projecting 3D coordinates of building corners available in a building database onto the image. Building areas are then divided into roof and facade areas. By comparing textures of the roof areas projected, building changes such as height change or building removal can be detected. New height values are estimated by adjusting building heights until projected roofs align to actual roofs observed in the image. If the projected image appeared in the image while no building is observed, it corresponds to a demolished building. By checking buildings in the original image whose roofs and facades areas are not projected, new buildings are identified. Based on these results, the building database is updated by the three categories of height update, building deletion, or new building creation. This method was tested with a KOMPSAT-3A image over Incheon Metropolitan City and Incheon building database available in public. Building change detection and building database update was carried out. Updated building corners were then projected to another KOMPSAT-3 image. It was confirmed that building areas projected by updated building information agreed with actual buildings in the image very well. Through this study, the possibility of semi-automatic building change detection and building database update based on single satellite image was confirmed. In the future, follow-up research is needed on technology to enhance computational automation of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.46-53
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• 2011

Nonlocal means denoising algorithm is one of the most widely used denoising algorithm. Because it performs well, and the theoretic idea is intuitive and simple. However the conventional nonlocal means algorithm has still some problems such as noise remaining in the denoised flat region and blurring artifacts in the denoised edge and pattern region. Thus many improved algorithms based on nonlocal means have been proposed. In this paper, we proposed new improved nonlocal means denoising algorithm by weight update through weights sorting and newly defined threshold. Updated weights can make weights more refined and definite, and denoising is possible without that artifacts. Experimental results including comparisons with conventional algorithms for various noise levels and test images show the proposed algorithm has a good performance in both visual and quantitative criteria.