• Journal of Digital Contents Society
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• v.14 no.4
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• pp.463-469
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• 2013

The set-based POI search algorithm showed better performance than the existing hard matching search when inaccurate queries are entered. In the set-based POI search algorithm, however, there is a problem that can't classify duplicate characters within a record. This is due to it's 'set-based' search property. To solve this problem, we improve the existing set-based POI search algorithm. In this paper, we propose and implement an improved set-based POI search algorithm that is able to deal duplicate characters properly. From the experimental results, we can find that our technique for duplicate characters improves the performance of the existing set based POI search algorithm.

• Journal of Korea Spatial Information System Society
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• v.9 no.3
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• pp.67-80
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• 2007

Recently, many studies on query processing algorithms has been done for spatial networks, such as roads and railways, instead of Euclidean spaces, in order to efficiently support LBS(location-based service) and Telematics applications. However, both a closest pairs query and an e-distance join query require a very high cost in query processing because they can be answered by processing a set of POIs, instead of a single POI. Nevertheless, the query processing cost for closest pairs and e-distance join queries is rapidly increased as the number of k (or the length of radius) is increased. Therefore, we propose both a closest pairs query processing algorithm and an e-distance join query processing algorithm using a POI-based materialization technique so that we can process closest pairs and e-distance join queries in an efficient way. In addition, we show the retrieval efficiency of the proposed algorithms by making a performance comparison of the conventional algorithms.

• Spatial Information Research
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• v.22 no.4
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• pp.21-38
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• 2014

Since users who search maps conduct their searching using the name they already know or is commonly called rather than formal name of a specific place, they tend to fail to find their destination. In addition, in typical web map service in terms of spatial searching of map. Location information of unintended place can be provided because when spatial searching is conducted with the vocabulary 'nearby' and 'in the vicinity', location exceeding 2 km from the current location is searched altogether as well. In this research, spatial range that human can perceive is calculated by extracting POI date with the usage of twitter data of SNS, constructing spatial relations with existing POI, which is already constructed. As a result, various place names acquired could be utilized as different names of existing POI data and it is expected that new POI data would contribute to select places for constructing POI data by utilizing to recognize places having lots of POI variation. Besides, we also expect efficient spatial searching be conducted using diverse spatial vocabulary which can be used in spatial searching and spatial range that human can perceive.

• KIISE Transactions on Computing Practices
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• v.21 no.3
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• pp.269-274
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• 2015

As smart device companies such as Google or Apple develop competitive mobile-based automotive operating systems and navigation systems, the range of choice for users in such markets is expanding. Navigation systems equipped with mobile operating systems have increased convenience for users. However, since an API for the POI databases used in navigation systems doesn't exist, the number of applications using POI data is insufficient. In this paper, we designed and implemented system calls for navigation operating systems with a focus on POI search, in order to resolve such limitations. The system calls support set-based POI search functions, and therefore provides solutions to search performance degradation problems caused by false inputs. As a result of performance evaluation, not only did the search performance improve, but there was also no problem in applying APIs in applications.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.121-123
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• 2005

최근 LBS(Location Based Service) 밑 텔레매틱스 응용의 효과적인 지원을 위해, 도로, 철도와 같은 공간 네트워크 데이터베이스에 관한 연구가 활발히 수행 중에 있다. 한편 공간 네트워크 데이터베이스에 대한 효율적인 접근을 위해, 공간 네트워크 자체의 데이터, POI 데이터, 이동 객체 데이터를 효율적으로 저장 및 색인하는 구조가 설계되었다[1]. 따라서 본 논문에서는 설계된 공간 네트워크 데이터베이스를 위한 저장/색인 구조를 구현하고 이를 공간 네트워크 자체의 데이터 검색, POI 데이터 검색, 이동 객체 궤적 검색 관점에서 성능평가를 수행한다. 아울러 기존에 연구되었던 접근 기법과 검색 성능을 비교한다.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.325-336
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• 2006

For supporting LBS service, recent studies on spatial network databases (SNDB) have been done actively. In order to gain good performance on query processing in SNDB, we, in this paper. design efficient storage and index structures for spatial network data, point of interests (POIs), and moving objects on spatial networks. First, we design a spatial network file organization for maintaining the spatial network data itself consisting of both node and edges. Secondly, we design a POI storage and index structure which is used for gaining fast accesses to POIs, like restaurant, hotel, and gas station. Thirdly, we design a signature-based storage and index structure for efficiently maintaining past, current, and expected future trajectory information of moving objects. Finally, we show that the storage and index structures designed in this paper outperform the existing storage structures for spatial networks as well as the conventional trajectory index structures for moving objects.

• Spatial Information Research
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• v.20 no.3
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• pp.67-81
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• 2012

Due to the recent advancement of cloud computing, the research on database outsourcing has been actively done. Moreover, the number of users who utilize Location-based Services(LBS) has been increasing with the development in w ireless communication technology and mobile devices. Therefore, LBS providers attempt to outsource their spatial database to service provider, in order to reduce costs for data storage and management. However, because unauthorized access to sensitive data is possible in spatial database outsourcing, it is necessary to study on the preservation of a user's privacy. Thus, we, in this paper, propose a spatial data encryption scheme to produce outsourced database from an original database. We also propose a k-Nearest Neighbor(k-NN) query processing algorithm that efficiently performs k-NN by using the outsourced database. Finally, we show from performance analysis that our algorithm outperforms the existing one.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.301-303
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• 2005

최근 자동차에서 위치$\cdot$지리정보를 제공하는 CNS(Car Navigation System)분야로 많은 개발이 되고 있으며, 이를 휴대용 단말기에 적용해 개인화하여 서비스를 제공하고 있는 추세이다. 휴대 단말기에 적용해 개인화 서비스를 제공하는 것을 PNS(Personal Navigation System)라 하며, 이 시스템은 이동 중인 사용자가 휴대용 기기에 공간 데이터를 저장하고 사용자의 위치를 기반으로 목적지까지의 경로를 안내하는 서비스 유형으로 사용자가 휴대하는 기기에 의해 정보가 제공되기 때문에 개인화 정보 제공이라는 특징을 가지고 있다. 또한 위치기반 PNS 서비스는 단순 위치 정보의 활용만이 아니라 위치 정보를 근간으로 POI(Poin of Interest)가 제공되어야 한다. 이를 위해서는 위치에 부가되는 다양한 POI의 정보와 함께 개인의 성향 정보가 적용되어야 한다. 그러나 아직까지 개인의 성향이나 특성에 따른 정보를 포함하지 않고 있다. 본 논문에서는 사용자가 선 입력한 성향정보와 History 정보로부터 추출되는 사용자 선호 특성 정보를 데이터베이스로 구축하고, 개인 선호 특성 정보를 반영하여 웹 또는 모바일 기기를 통해 POI 서비스를 제공 받을 수 있는 PNS시스템을 제안하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1113-1116
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• 2005

PNS 시스템은 개인 휴대 단말기나 이동전화기로 제공되는 위치 지리 정보 서비스로 개인화된 서비스라 할 수 있다. 그러나 위치기반 PNS 서비스는 단순 위치 정보의 활용만이 아니라 위치 정보를 근간으로 POI(Poin of Interest)가 제공되어야 한다. 이를 위해서는 위치 및 위치에 부가되는 상황 정보를 바탕으로 개인의 개별화된 정보가 포함되어야 한다. 그러나 이러한 서비스에서 제공되는 위치 지리 정보는 개인의 성향이나 특성에 따른 정보를 포함하지 않기 때문에 개인 선호 특성 정보가 반영되지 않아 무분별한 POI 정보가 제공되고 있다. 본 논문에서는 사용자가 선 입력한 성향정보와 History 정보로부터 추출되는 사용자 선호 특성 정보를 데이터베이스로 구축하고, 개인 선호 특성 정보를 반영하여 웹 또는 모바일 기기를 통해 POI 서비스를 제공 받을 수 있는 PNS시스템을 제안하였다.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.57-64
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• 2017

Short message service (SMS) is one of the most important communication methods for people who use mobile phones. However, illegal advertising spam messages exploit people because they can be used without the need for friend registration. Recently, spam message filtering systems that use machine learning have been developed, but they have some disadvantages such as requiring many calculations. In this paper, we implemented a spam message filtering system using the set-based POI search algorithm and sentence similarity without servers. This algorithm can judge whether the input query is a spam message or not using only letter composition without any server computing. Therefore, we can filter the spam message although the input text message has been intentionally modified. We added a specific preprocessing option which aims to enable spam filtering. Based on the experimental results, we observe that our spam message filtering system shows better performance than the original set-based POI search algorithm. We evaluate the proposed system through extensive simulation. According to the simulation results, the proposed system can filter the text message and show high accuracy performance against the text message which cannot be filtered by the 3 major telecom companies.