• Journal of Korea Spatial Information System Society
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• v.11 no.1
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• pp.115-126
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• 2009

Recent development in wireless communication and mobile positioning technologies makes Location-Based Services (LBSs) popular. However, because, in the LBSs, users request a query to database servers by using their exact locations, the location information of the users can be misused by adversaries. Therefore, a mechanism for users' privacy protection is required for the safe use of LBSs by mobile users. For this, we, in this paper, propose a efficient cloaking region creation scheme using Hilbert curves in distributed grid environment, so as to protect users' privacy in LBSs. The proposed scheme generates a minimum cloaking region by analyzing the characteristic of a Hilbert curve and computing the Hilbert curve values of neighboring cells based on it, so that we may create a cloaking region to satisfy K-anonymity. In addition, to reduce network communication cost, we make use of a distributed hash table structure, called Chord. Finally, we show from our performance analysis that the proposed scheme outperforms the existing grid-based cloaking method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.229-234
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• 2013

As the popularization and proliferation of smart phone and location based services, the necessity and importance of the location based service based on the smart phone becomes significant. But existing technologies could not be applied in real situation due to the lack of accuracy, economy, and convenience, the method using the signal strength of WLAN is not accurate. In this paper, the technical back ground, implementation issue, and measurement result are described for the proposed relative positioning technology using acoustic signal and Bluetooth with smart phone. It is possible to measure the position of the smart phone with accuracy and simple device, and it is very proper especially for the indoor location based intelligent services.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.303-309
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• 2011

Situation awareness services which increasingly expand their influence in everyday life can be classified into location-based service and social network service. Their quality of service (QoS) can be differed based on the location accuracy of smart phones and accuracy of directional recognition technology. This study was conducted to analyze GPS, digital compass, radio communication, and geospatial web information which can provide a clue in using the situation aware services based on lab experiments and surveys. According to the result of lab experiment on accuracy of determining location / direction with smart phones, owing to inherent lack of indoor accuracy in determining position and direction, as well as errors in spatial data used as platform, it was found that devices were not provided with sufficiently accurate data when using the situation aware services indoors compared to outdoors. To enhance accuracy of determining indoor positions, there are several methods including location metering based on Wi-Fi, which had several problems compared with GPS used in outdoor environment. Thus, it was determined that more study would be necessary to solve these issues.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.2056-2063
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• 2012

In a port terminal, containers are stored and transshipped by yard tractors and crane vehicles. For operation efficiency of the terminal, location information of these vehicles is an essential factor. However, most of port terminals try to estimate location of these assets using indirect methods such as event tracking of shipping or unshipping containers. Because these kinds of events are rarely occurred, location of the event includes seriously locating error compared to a real location of vehicle. In this paper, we propose a real-time asset tracking system to obtain accurate and reliable location of terminal assets. The proposed system overcomes a location estimation error caused by container stacks which interrupt wireless communication. In order to mitigate uncertainty and increase accuracy of location estimation, we designed hardwares and multi-step locating system to resolve additional preblems. We implemented system components, and installed these at a port environment for evaluation. The result shows superiority of the system that the accuracy is approximately 5.87 meters (CEP).

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.552-557
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• 2015

Recent performed by recognizing a user's location, various services have been tailored focus on short-range wireless communication technology. A beacon in which is attracting attention as next-generation technology. Beacon is a terminal by utilizing the frequency of the non-audible area can not be bluetooth and human sending and receiving terminals and information, Apple recently iBeacon like a low-power Bluetooth (BLE; bluetooth low energy) based beacon showing a tendency to rise into the mainstream there. Services using a beacon is basically installs the terminal in a certain place indoor. It is characterized by providing the user the services to catch the user's position, even automatically take a separate action. Various types of location-based service provided by the target interior space began to attract attention. A variety of location-based services are provided in the interior space in order to be successfully deployed and provide guidance to the interior space, the movement route and the like are essentially required to build various types of information. In this paper, for efficient indoor positioning by varying the signal strength of the beacon in such areas were measured and analyzed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.475-478
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• 2014

This paper proposed the position tracking and recognition method of workers and cars in construction field. The reason why the position of workers and cars has to be tracked is to prevent the safety accident, emergency rescue, and theft of building materials by unauthorized people and car, etc. To realize the tracking, it needs to adopt the Information Telecommunication technology to the construction field as an integrated support system. In this paper, we proposed the continuous positioning tracking algorithm for workers and moving cars using the selected wireless communication network. And we proposed the virtual gateway method to detect the entrance status of moving workers and cars. All of these proposed methods are evaluated in real construction field using the prototype of support system made by ourselves.

• Journal of Korea Spatial Information System Society
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• v.7 no.2 s.14
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• pp.47-56
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• 2005

Recently, with the rapid development of mobile computing, wireless positioning technologies, and the generalization of wireless internet, LBS (Location Based Service) which utilizes location information of moving objects is serving in many fields. In order to serve LBS efficiently, the location data server that periodically stores location data of moving objects is required. Formerly, GIS servers have been used to store location data of moving objects. However, GIS servers are not suitable to store location data of moving objects because it was designed to store static data. Therefore, in this paper, we designed and implemented an extended SLDS(Short-term Location Data Subsystem) for real-time Location Based Services. The extended SLDS is extended from the SLDS which is a subsystem of the GALIS(Gracefully Aging Location Information System) architecture that was proposed as a cluster-based distributed computing system architecture for managing location data of moving objects. The extended SLDS guarantees real-time service capabilities using the TMO(Time-triggered Message-triggered Object) programming scheme and efficiently manages large volume of location data through distributing moving object data over multiple nodes. The extended SLDS also has a little search and update overhead because of managing location data in main memory. In addition, we proved that the extended SLDS stores location data and performs load distribution more efficiently than the original SLDS through the performance evaluation.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.12a
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• pp.33-38
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• 2004

최근 들어 무선인터넷 및 모바일 컴퓨팅 기술의 급속한 발전과 함께 향후 그 수요가 증대될 것으로 예상되는 분야가 위치기반 서비스(LBS: Location Based Service) 기술이다. 위치기반 서비스는 이동 중인 사용자의 위치정보를 여러 가지 부가 서비스와 결합시켜 다양한 서비스를 제공하는 것으로 휴대 단말기와 무선 네트워크, 위치 측위 기술, 각종 응용 어플리케이션 등이 총체적으로 합쳐져 제공되는 서비스로 이동성, 개인성, 적시성 등을 사용자에게 제공해 주는 GIS의 차세대 핵심기술로 발전이 예상되는 분야이다[2][3]. 현재 미국, 유럽 등을 중심으로 3GPP/3GPP2, OMA, OGC, ISO, MAGIC 등의 국제 표준화 기구 및 단체에서 위치기반 서비스에 대한 표준화가 활발히 진행되고 있으며, 국내에서도 그 중요성을 인지하고 LBS 표준화에 정보, 업체, 학계 및 연구기관의 LBS 관련 전문가들로 구성된 LBS 표준화 포럼을 중심으로 국내 LBS 기술 표준을 위한 연구가 활발하게 진행되고 있다. 본 연구에서는 국내 LBS 표준들을 기반으로 위치기반 서비스에서 가장 기본적이고 핵심이 되는 서비스를 제공하는 표준 참조 시스템을 개발하고자 한다. 개발하고자 하는 표준 참조 시스템은 사용자의 위치를 추적하고 확인할 수 있는 위치추적 서비스와 주변 시설물 검색을 위한 디렉토리 서비스, 목적지까지의 경로를 안내하는 항법 서비스를 위한 기능 인터페이스 표준을 제공한다. 위치기반 서비스를 위한 표준 창조 시스템은 위치기반 응용 서비스의 기능 규격과 표준 인터페이스를 제공함으로써 위치기반 서비스 및 시스템 개발의 중복을 방지하고 상호 호환성을 확보 할 수 있다.문제에 적용이 가능한 창조 모델로 이용될 수 있을 것으로 생각된다.}94,\;29.4{\pm}30.3,\;45.1{\pm}44$로 Mel 10군과 Mel 30군이 유의적인 감소를 보였으나(p<0.05) 이들 두 군 간의 차이는 나타나지 않았다. 이상의 결과로, 랫트에서 복강수술 후 melatonin 10mg/kg투여가 복강 내 유착 방지에 효과적이라고 생각된다.-1}{\cdot}yr^{-1}$로서 두 생태계에 축적되었다.여한 3,5,7군에서 PUFA 함량이 증가한 반면, SFA 함량은 감소하여 P/S 비율, n-3P/n-6P 비율은 증가하는 경향이었으며 이는 간장의 인지질, 콜레스테롤 에스테르, 총 지질의 지방산조성에서도 같은 경향을 볼 수 있었다.X>$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 대부분을 차지하였다. 야생 돌복숭아 과육 중의 지방산 조성은 포화지방산이 16.74%, 단불포화지방산 17.51% 및 다불포화지방산이 65.73%의 함유 비율을 보였는데, 이 중 다불포화지방산인 n-6계 linoleic acid$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 지질 구성 총 지방산의 대부분을 차지하는 함유 비율을 나타내었다.했다. 하강하는 약 4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.1003-1006
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• 2009

Recently, Ubiquitous computing technology is increasing necessity for object recognition and a location tracking technology to meet various applications. The location tracking technology is the fundamental to the Context-Aware of users in Ubiquitous environment and its efficiency has to be improved using IEEE 802.15.4 ZigBee used in current infra such as ubiquitous sensor network. But because the IEEE 802.15.4 ZigBee protocol has limitation to apply location tracking technology such as ToA and TDoA, Zone-based Location Tracking technology using RSSI is needed. In this paper suggests RSSI-based 802.15.4 ZigBee local positioning protocol to support a positioning tracking service in Ubiqutous environment. And Zone-based location tracking system is designed for actual the indoor location tracking service.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.2
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• pp.133-148
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• 2011

Construction sites are becoming larger and complex with the growth of national economy. Accordingly, it is important to identify real-time information about materials, equipments, and manpower during construction at sites. Even though research utilizing position tracking sensors has been conducted in architectural engineering fields, this area of research is almost nil in civil engineering fields. Therefore, a feasibility study to find a way to apply position tracking sensors to an in-situ tunnel construction site adopting conventional tunnelling method is performed in this study. A methodology is proposed that the progress management of the tunnelling work can be monitored by checking construction materials needed at job site and the safety management system can be assessed by checking distance between in-situ workers and construction equipments. The most representative materials were identified so that IT technology can be applied by attaching and monitoring sensors to the selected materials. Also, time of arrival (TOA) for a position determination technology along with a wireless network technology was chosen and build wireless network system. The adopted methodology was applied to an in-situ tunnelling site, and verified the usefulness of the proposed system.