• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.89-95
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• 2009

This paper proposes a tag indexing scheme for RFID tag using spatial index. The tag being used for the inventory management and the tag's location is determined by the position of readers. Therefore, the reader recognizes the tag, which is attached products and thereby their positions can be traced down. In this paper, we propose hTag-tree( Hybrid Tag index) which manages RFID tag attached products. hTag-tree is a new index, which is based on tag's attributes with fast searching, and this tag index manages RFID tags using reader's location. This tag index accesses rapidly to tags for insertion, deletion and updating in dynamic environment. This can minimize the number of node accesses in tag searching comparing to previous techniques. Also, by the extension of MER in present tag index, it is helpful to stop the lowering of capacity which can be caused by parent node approach. The proposed index experiment deals with the comparison of tag index. Fixed Interval R-tree, and present spatial index, R-tree comparison. As a result, the amount of searching time is significantly shortened through hTag-tree node access in data search. This shows that the use of proposed index improves the capacity of effective management of a large amount of RFID tag.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.233-246
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• 2005

To enhance the user response time of content-based retrieval service for multimedia information, several multi-dimensional index schemes have been proposed. M-tree, a well-known multidimensional index scheme is of metric space access method, and is based on the distance between objects in the metric space. However, since the overlap between index spaces of nodes might enlarge the number of nodes of M-tree accessed for query processing, the user response time for content-based multimedia information retrieval grows longer. In this paper, we propose a node split algorithm which is able to reduce the sire of overlap between index spaces of nodes in M-tree. In the proposed scheme, we choose a virtual center point as the routing object and entry redistribution as the postprocessing after node split in order to reduce the radius of index space of a node, and finally in order to reduce the overlap between the index spaces of routing nodes. From the experimental results, we can see the proposed split algorithm reduce the overlap between index space of nodes and finally enhance the user response time for similarity-based query processing.

• Journal of Korea Spatial Information System Society
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• v.8 no.1 s.16
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• pp.59-75
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• 2006

One of the most challenging and encouraging applications of state-of-the-art technology is the field of traffic control systems. It combines techniques from the areas of telecommunications and computer science to establish traffic information and various assistance services. The support of the system requires a moving objects database system (MODB) that stores moving objects efficiently and performs spatial or temporal queries with time conditions. In this paper, we propose schemes to distribute an index nodes of trajectory based on spatio-temporal proximity and the characteristics of moving objects. The scheme predicts the extendible MBB of nodes of index through the prediction of moving object, and creates a parallel trajectory index. The experimental evaluation shows that the proposed schemes give us the performance improvement by 15%. This result makes an improvement of performance by 50% per one disk.

• 한국공간정보시스템학회:학술대회논문집
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• 2003.11a
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• pp.163-168
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• 2003

현실 세계에서 자동차, 비행기, 태풍의 이동 등과 같이 시간에 따라 연속적으로 위치 및 모양이 변화하는 객체를 이동 객체라 한다. 이와 같은 이동 객체 정보를 다루기 위해서는 연속적으로 변화하는 정보를 저장해야 하며, 이로 인해 대용량 정보를 효과적으로 다루기 위한 색인이 필요하다. 특히, LBS를 제공을 위한 GPS 환경에서의 차량 관리 시스템 등에서는 이동 객체 관리를 위해 빠른 검색을 필요로 한다. 그리고, 기존의 이동 객체 색인은 대부분 R-트리의 구조를 가지기 때문에, 데드 스페이스 및 오버랩 등 R-트리의 문제점을 갖게 되고, 고려하는 초점에 따라 이 문제가 더 커진다. 따라서, 이 논문에서는 PDA를 활용한 차량 추적 시스템을 개발하고, R-트리의 문제점을 해결하기 위한 MP-트리 노드 연산 기법을 제안한다. 제안된 노드 연산 기법은 하위 노드의 경계 정보를 순서대로 저장함으로써, 데드 스페이스 및 오버랩으로 인한 불필요한 검색 비용과 분할 비용을 줄이고, 특정 시점 질의 및 시공간 범위 질의를 효과적으로 처리한다. 기존 이동 객체 색인과 비교한 실험으로부터 이동 객체 질의 처리 및 공간 활용에 대해 노드 연산이 유용하게 쓰임을 확인하였다.

• Journal of Korea Spatial Information System Society
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• v.9 no.1
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• pp.31-43
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• 2007

Sensor data have the characteristics such as numerous and continuous data. Therefore, it is required to develop an index which could retrieve a specific sensor data efficiently from numerous sensed data. The index should have an efficient delete operation for the past data to support the data archiving. In this paper, we have proposed and implemented an index splitting technique to support the sensor data archiving. These splitted indexes compose of a virtual index (that is, index management component), which is shown as single tree from outside. Experimental results show that in the case of 100,000 insert operations the splitted index performs 8% better than the traditional TB-tree maximumly. And the splitted index outperforms TB-tree with retrieving queries when the region of query is small and the size of time domain is large.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.127-129
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• 2003

최근 GPS기능을 탑재한 휴대폰ㆍPDA등의 모바일 장치를 사용하여 위치 기반 서비스 (LBS : Location Based Service)를 이용하는 사용자가 급증하고 있다. 이에 대용량의 공간 데이터베이스에 대해 효율적 검색을 가능하게 하기 위한 색인이 필요하다. 공간 데이터베이스를 위한 다차원 공간 색인 기법으로는 R-Tree가 널리 사용되고 있다. 기존의 R-Tree를 이용한 검색은 질의 영역과 관계없는 공간 데이터까지 검색하는 고비용의 연산이 요구되며, 사용자의 질의 위치 단위(Granularity)를 고려하지 않아 사용자의 빠른 검색 응답시간 및 질의 영역에 대한 정확한 공간 객체 검색에 대해 충족하지 못한다. 이에 본 논문에서는 임의의 셀 안에 존재하는 공간 데이터가 자신이 속한 노드의 전체 MBR(Union MBR)영역과 셀 영역에 따라 셀 레벨 값을 구성하는 CLR-Tree(Cell Leveling R-Tree)를 제안한다. CLR-Tree를 사용할 경우 사용자의 질의 영역 셀 레벨 값과 데이터베이스에 저장된 공간 데이터의 셀 레벨 값을 비교한 뒤 겹침 연산 대상이 되는 공간 객체 수를 줄임으로써 검색 시간을 향상시킬 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2140-2146
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• 2009

Since tags do not have location informations, the identifiers of tags which are symbolic data are used as the location informations. Therefore, it is difficult to define the proxmity between two trajectories of tags and inefficient to process the user queries for tags. In this paper, we define the perceptual space to model the location of a tag and propose the proximity of the perceptual spaces. The proximity of the perceptual spaces is composed of the static proximity and dynamic proximity. Using the proximity of the perceptual spaces, it is possible to measure the proximity between two trajectories of tags and build the efficient indexes for tag trajectories. We evaluated the performance of the proposed proximity function for tag trajectories on the IR-tree and the $R^*$-tree.

• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.543-552
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• 2005

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. The disk-based spatial indexing techniques, however, cannot direct apply to main memory databases, because the main purpose of disk-based techniques is to reduce the number of disk accesses. In main memory-based indexing techniques, the node access time is much faster than that in disk-based indexing techniques, because all index nodes reside in a main memory. Unlike disk-based index techniques, main memory-based spatial indexing techniques must reduce key comparing time as well as node access time. In this paper, we propose an efficient spatial index structure for main memory-based databases, called Tmr-tree. Tmr-tree integrates the characteristics of R-tree and T-tree. Therefore, Nodes of Tmr-tree consist of several entries for data objects, main memory pointers to left and right child, and three additional fields. First is a MBR of a self node, which tightly encloses all data MBRs (Minimum Bounding Rectangles) in a current node, and second and third are MBRs of left and right sub-tree, respectively. Because Tmr-tree needs not to visit all leaf nodes, in terms of search time, proposed Tmr-tree outperforms R-tree in our experiments. As node size is increased, search time is drastically decreased followed by a gradual increase. However, in terms of insertion time, the performance of Tmr-tree was slightly lower than R-tree.

• Spatial Information Research
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• v.19 no.5
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• pp.63-74
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• 2011

Recently, there has been much interest in the spatial query which energy-efficiently acquires sensor readings from sensor nodes inside specified geographical area of interests. The centralized approach which performs the spatial query at a server after acquiring all sensor readings, though simple, it incurs high wireless transmission cost in accessing all sensor nodes. In order to remove the high wireless transmission cost, various in-network spatial indexing schemes have been proposed. They have focused on reducing the transmission cost by performing distributed spatial filtering on sensor nodes. However, these in-network spatial indexing schemes have a problem which cannot optimize both the spatial filtering and the wireless routing among sensor nodes, because these schemes have been developed by simply applying the existing spatial indexing schemes into the in-network environment. Therefore, we propose a new distributed spatial indexing scheme of the GR-tree. The GR-tree which form s a MBR-based tree structure, can reduce the wireless transmission cost by optimizing both the efficient spatial filtering and the wireless routing. Finally, we compare the existing spatial indexing scheme through extensive experiments and clarify our approach's distinguished features.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.59-62
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• 2004

이동객체 색인에 관한 기존 연구는 실외 환경의 빠른 속도로 이동하는 많은 이동객체들을 대상으로 과거 궤적과 현재 위치 및 미래 위치를 검색하는 색인 기법들이었다. 그러나 쇼핑몰이나 대형 박물관과 같은 건물의 실내나 놀이동산과 같은 한정된 영역의 이동객체들은 실외 환경에서처럼 빠른 이동속도를 가지고 있지 않다. 또한 이동객체들의 이동하는 영역이 한정되어 있을 뿐만 아니라 최대 수용인원 등이 정해져 있다. 본 논문에서는 이러한 특성을 갖는 실내 환경에 적합한 색인 기법으로 현재 그리고 미래 위치 질의 처리를 위한 공간색인과 시간 색인을 분리한 두 개의 색인 구조를 갖는 새로운 색인 기법과 가까운 미래 시간의 특정 영역에 있는 이동객체들의 수에 대한 질의응답을 위한 시공간 히스토그램을 구성하고, 적용하는 방법을 제안한다.