• Spatial Information Research
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• v.20 no.2
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• pp.137-153
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• 2012

Until now, many indexing methods that can reduce update cost have been proposed for managing massive moving objects. Because indexing methods for moving objects have to be updated periodically for managing moving objects that change their location data frequently. However these kinds indexing methods occur big load that exceed system capacity when the number of moving objects increase dramatically. In this paper, we propose the update frequency reducing method to combine MapReduce and existing indices. We use the update request grouping method for each moving object by using MapReduce. We decide to update by comparing the latest data and the oldest data in grouping data. We reduce update frequency by updating the latest data only. When update is delayed, for the data should not be lost and updated periodically, we store the data in a certain period of time in the hash table that keep previous update data. By the performance evaluation, we can prove that the proposed method reduces the update frequency by comparison with methods that are not applied the proposed method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.59-65
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• 2012

In this paper, we proposed a method for automatic detection of a updating object from spatial data sets of different scale and updating cycle by using areal feature matching based on shape similarity. For this, we defined a updating object by analysing matching relationships between two different spatial data sets. Next, we firstly eliminated systematic errors in different scale by using affine transformation. Secondly, if any object is overlaid with several areal features of other data sets, we changed several areal features into a single areal feature. Finally, we detected the updating objects by applying areal feature matching based on shape similarity into the changed spatial data sets. After applying the proposed method into digital topographic map and a base map of Korean Address Information System in South Korea, we confirmed that F-measure is highly 0.958 in a statistical evaluation and that significant updating objects are detected from a visual evaluation.

• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.99-107
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• 2020

An underground integrated map is being built for underground safety management and is being updated periodically. The map update proceeds with the procedure of deleting all previously stored objects and saving newly entered objects. However, even unchanged objects are repeatedly stored, deleted, and stored. That causes the delay of the update time. In this study, in order to shorten the update time of the integrated map, an updated object and an unupdated object are separated, and only updated objects are reflected in the underground integrated map, and a system implementing this technology is described. For the updated object, an object comparison method using the center point of the object is used, and a quad tree is used to improve the search speed. The types of updated objects are classified into addition and deletion using the shape of the object, and change using its attributes. The proposed system consists of update object detection, extraction, conversion, storage, and history management modules. This system has the advantage of being able to update the integrated map about four times faster than the existing method based on the data used in the experiment, and has the advantage that it can be applied to both ground and underground facilities.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.553-559
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• 2020

In order to prevent subsidence in urban areas, which is a major cause of damage to aging underground facilities, an integrated underground space map is being produced for systematic management of underground facilities. However, there is a problem of delaying the update time because an unupdated underground facility object is included in the process of updating the underground space integrated map. In this paper, we proposed a method to shorten the update time of the integrated map by selecting only the updated objects required for the update process of the underground space integrated map based on the central point of the underground facilities. Through the comparison of the centroid, the number of search targets is greatly reduced to shorten the search speed, and the distance of the actual location values between the two objects is calculated whether or not the objects are the same. The proposed method shows faster performance as the number of data increases, and the updated object can be reflected in the underground space integrated map about four times faster than the existing method.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.477-490
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• 2006

Existing index structures need very much update cost because they repeat delete and insert operations in order to update continuously moving objects. In this paper, we propose a new index structure which reduces the update cost of continuously moving objects. The proposed index structure consists of a space partitioning index structure that stores the location of the moving objects and an auxiliary index structure that directly accesses to their current positions. In order to increase the fanout of the node, it stores not the real partitioning area but kd-tree as the information about the child node of the node. In addition, we don't traverse a whole index structure, but access the leaf nodes directly and accomplish a bottom-up update strategy for efficiently updating the positions of moving objects. We show through the various experiments that our index structure outperforms the existing index structures in terms of insertion, update and retrieval.

• Journal of Cadastre & Land InformatiX
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• v.44 no.1
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• pp.127-138
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• 2014

It can be effective to extract and apply the updated information from the newly updated map data for updating road data of topographic map. In this study, update target data and update reference data are overlaid and the update objects are explored using network matching technique. And the network objects are classified into five matching and update cases and the update processes for each case are applied to the test data. For this study, road centerline data of digital topographic map is used as an update target data and road data of Korean Address Information System is used as an update reference data. The buffer-based network matching method is applied to the two data and the matching and update cases are classified after calculating the overlaid ratio of length. The newly updated road centerline data of digital topographic map is generated from the application of update process for each case. As a result, the update information can be extracted from the different map dataset and applied to the road network data updating.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.05a
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• pp.47-52
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• 2005

본 논문에서는 4S-Van에 의하여 수집된 동영상으로부터 공간정보, 특히 도로 표지판을 구축하고 갱신할 수 있는 변화탐지 기술에 대하여 소개한다. 4S-Van은 차량의 위치/자세정보와 영상을 동기화하여 취득하고 이로부터 공간객체의 위치정보를 구축하는 시스템이다. 4S-Van에서 취득한 영상으로부터 표지판을 구축하고 갱신하는 작업은 수동 입력에 의한 많은 시간을 필요로 하며, 본 논문에서는 이를 해결하기 위하여 영상으로부터 표지판 정보를 구축 및 갱신할 때 수동 입력을 최소화하기 위한 방법을 제안하고 시스템을 구축한 결과를 제시한다. 4S-Van 데이터로부터 객체의 위치를 결정하는 사진측량기술과 영상처리기술을 결합하여 공간객체를 인식할 수 있는 기술을 제안하였으며, 새로 취득된 동영상에서 객체의 변화를 탐지함으로써 해당객체의 정보만을 새로 구축할 수 있도록 하였다. 개발된 시스템은 표지판 정보의 효율적 구축과 갱신을 지원할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.332-335
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• 2011

GPS 칩을 내장한 다양한 이동 통신 기기의 사용으로 위치 정보를 이용한 응용이 점차 확산될 전망이다. 위치 정보를 기반으로 한 응용 시스템에서는 다수 이동 객체의 위치 정보를 실시간으로 기록하고, 미래 시점의 객체 위치를 추정할 수 있어야 한다. 이런 요구에 따라 효과적인 이동 객체 색인에 고안된 기법이 TPR*-트리이다. 하지만 TPR*-트리는 고정 위치 색인에 최적화된 R-트리에 기본을 두었기 때문에 갱신 비용이 매우 커질 수 있다는 문제가 있다. R-트리에서는 갱신 연산이 빈번하지 않을 수 있지만 TPR*-트리의 경우는 이동 객체가 속도를 변화시킬 때마다 갱신 연산이 요구되기 때문에 상대적으로 매우 큰 갱신 비용이 발생할 수 있다. 이런 문제점을 부분적으로 해결하기 위해 본 논문에서는 쿨링다운 노드를 사용한 TPR*-트리를 제안한다. 제안된 트리는 트리의 상위 계층에 일부 이동 객체를 버퍼링함으로써 갱신 연산을 최소화 할 수 있다. 또한 지나친 사장 영역(dead space)의 확대를 방지함으로써 검색 성능 저하를 효과적으로 줄일 수 있다.

• The KIPS Transactions:PartD
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• v.8D no.1
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• pp.32-43
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• 2001

Due to the limitation of data modeling power and the view update ambiguity, relational view is limitedly used for engineering applications. On the contrary, object-oriented database view would playa vital role in defining custom interface for engineering applications because the above two limitations of the relational view are overcome by the object-oriented view. Above all, engineering application data interface should fully support updates. More specifically, updates against the data interface needs to be unambiguously defined and its semantic behavior should be equal to base schema updates'. For this purpose, we define the notion of update semantic preserving which means that view updates displays the same semantics as base schema. Besides, in order to show the feasibility of this characteristics, specific and concrete algorithms for update preserving updates are presented for a CAD specialized object-oriented database view - MultiView. This paper finds that in order that virtual classes coudld form a schema with 'isa' relationships rather than just a group of classes, the update semantics on the virtual classes should be defined such that the implied meaning of 'isa' relationships between classes are not to be violated. Besides, as its sufficiency conditions, we derived the update semantics and schema constituable conditions of the virtual classes that make view schemas look like base schemas. To my best knowledge, this is the first research that presents the sufficiency conditions by which we could defined object-oriented views as integrated schemas rather than as separate classes.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.12a
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• pp.60-65
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• 2004

최근 무선/이동 통신 기술과 GPS 기술의 발달은 휴대폰을 소지하고 이동하는 사람이나 GPS 수신기를 탑재한 차량과 같은 이동객체의 위치 정보와 관련된 서비스의 제공을 가능하게 하였다. 이러한 환경에서 연속적으로 변경되는 이동객체의 위치 정보는 데이터베이스에 빈번한 갱신 연산을 요구하게 되고, 이는 전체 시스템의 성능을 저하시키는 원인이 된다. 이러한 문제를 해결하기 위하여 R-Tree와 같은 공간색인 구조를 확장하여 갱신 효율을 높이기 위한 연구가 진행되어 왔지만, 시스템의 전체 성능은 오히려 저하되는 문제를 가져왔다. 이 논문에서는 이동객체의 질의 처리 성능뿐만 아니라 객체의 빈번한 위치 갱신을 효율적으로 처리할 수 있는 방법으로 고정 그리드와 R-Tree를 혼합한 형태의 색인 기법을 제안한다. 제안된 색인 기법은 R-Tree에서 색인의 재조직화로 인해 갱신 성능이 저하되는 문제를 해결하기 위하여 셀 기반 색인 기법인 고정 그리드를 이용하여 이동객체의 위치 정보를 저장하고, 고정 그리드에서 객체의 편중 분포로 인한 오버플로 문제를 처리하기 위하여 오버플로가 발생한 각각의 셀들을 R-Tree로 관리한다. 또한, 객체의 밀도가 낮은 셀들을 하나의 버켓으로 공유하여 관리함으로써 저장 공간을 효율적으로 활용한다. 제안된 방법을 다양한 평가 요소를 통해 실험한 결과, 기존의 R-Tree보다 뛰어난 갱신 성능을 보였으며, 질의 처리에 대해서도 성능이 향상되었음을 보였다.