• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10c
• /
• pp.235-237
• /
• 2004

최근 급속히 발전하고 있는 유비쿼터스 컴퓨팅의 대두는 센서네트워크 산업 발전에 않은 영향을 끼치고 있다. 센서네트워크는 군사, 과학, smart home, 환경, 농업등 많은 분야에 응용할 수 있으며, 기존의 유무선 네트워크와 항께 미래를 같이할 차세대 네트워크로 평가 받고 있다. 본 논문에서는 저전력 무선 센서네트워크인 MICA2[1]를 이용하여, room size의 건물내의 공간에서 3자원위치를 인식 및 추적 할 수 있는 저가형 시스템에 대하여 설계 및 구현한다.

• Proceedings of the KAIS Fall Conference
• /
• 2008.05a
• /
• pp.108-110
• /
• 2008

최근 무선 통신 기술의 발달은 장비를 간편화 하고 편리화 시키게 되었다. 또한 다양한 서비스를 창출 할 수 있는 기반이 마련하였다. 하지만 무선 랜의 다양한 서비스와 접속성의 확대는 보안의 취약점을 야기 시켰다. 본 논문에서는 IEEE802.11 무선 랜 서비스를 통하여 PDA 상에서 AP의 정보를 받아 무선 랜 보안 서비스의 특성과 취약성을 살펴보고 PDA 기반 위치 추적 시스템을 구현을 하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04b
• /
• pp.502-504
• /
• 2004

지능형 교통 정보 시스템을 구축할 때 반드시 요구되는 것이 바로 위치 정보이다. 대부분 GPS (Global Positioning System)와 같은 장치를 이용하여 위치 정보를 얻게 된다. 그러나 GPS수신기와 같은 장치는 상대적으로 비용이 크기 때문에 차량마다 장착하여 지능형 교통 정보 시스템에 활용하기에는 부담이 된다. 따라서 본 논문에서는 기존의 무선랜으로 위치를 추적하는 방법을 버스 지능형 교통 정보 시스템에 적용한 시스템 구조를 제안한다. 버스는 노선의 자유도가 택시 같은 다른 교통편에 비해서 작으므로 무선랜으로 위치 추적하는 방법은 다른 위치 추적 방법에 비해 경제적으로 보다 적합하다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.12
• /
• pp.1883-1890
• /
• 2013

Location detection technology (LDT) is one of the core techniques for location based service (LBS) in wireless communication for improving resource management and quality of services. The location of a mobile station (MS) is estimated using the time of arrival (TOA) technique based on three circles with centers corresponding to coordinates of three base stations (BSs) and radius corresponding to distances between MS and BSs. For accurately estimating the location of MS, three circles should meet at a point for the trilateration method, but they generally do not meet a point because the radius is increased depending on the number of time delay for estimating the distance between MS and BS and the carrier frequency. The increased three circles intersect at six points and the three intersection points among them should be generally placed close to coordinate of the location for the specific MS. In this paper, we propose the shortest distance algorithm for TOA trilateration method, to select three interior intersection points from entire six points. The proposed approach selects three intersection points with the shortest distances between coordinates of MS and intersection points and determines the averaged coordinate of the selected three points, as the location of the specific MS. We demonstrate the performance of the proposed algorithm using a typical computer simulation example.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.5
• /
• pp.77-87
• /
• 2018

Many researches have been focused on localization in WSNs. However, the solutions for localization in static WSN are hard to apply to the mobile WSN. The solutions for mobile WSN localization have the assumption that there are a significant number of anchor nodes in the networks. In the resource limited situation, these solutions are difficult in applying to the static and mobile mixed WSN. Without using the anchor nodes, a localization service cannot be provided in efficient, accurate and reliable way for mixed wireless sensor networks which have a combination of static nodes and mobile nodes. Also, accuracy is an important consideration for localization in the mixed wireless sensor networks. In this paper, we presented a method to satisfy the requests for the accuracy of the localization without anchor nodes in the wireless sensor networks. Hop coordinates measurements are used as an accurate method for anchor free localization. Compared to the other methods with the same data in the same category, this technique has better accuracy than other methods. Also, we applied a minimum spanning tree algorithm to satisfy the requests for the efficiency such as low communication and computational cost of the localization without anchor nodes in WSNs. The Java simulation results show the correction of the suggested approach in a qualitative way and help to understand the performance in different placements.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.11a
• /
• pp.725-728
• /
• 2006

Recently, It is gradually increasing about need of various information service based of Location that in compliance with rapidly development wireless internet terminal using the real-time location information at mobile environment. But existing information depends service provision method to information provider. so It is many insufficient tailorable information provision about user individuals each other propensity. For this, It need Service skill to provide easily information about tailorable POI(Point Of Interest) of user preference using information based of Location in mobile computing environment. Therefore In this paper, It is use information service based of location in mobile environment. So It analyzes POI information in compliance with propensity of user and It proposes to provide information about service model. It provides to follow individuals propensity analysis POI information service based of location in proposed model. so It provides actively more value information to user.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.9 no.2
• /
• pp.30-41
• /
• 2006

This paper proposes an e-logistics system supporting efficient vehicle moving trajectory management. Recent advances in wireless communications have given rise to a number of location-based services including logistics vehicle tracking, cellular phone user's location finding, and location-based commerce. Logistics systems typically entail tracking vehicles for purposes of the logistics center knowing the whereabouts of the vehicles and/or consignments. Moreover, storing and managing location trajectory of continuously moving vehicles and consignments is necessary for supporting efficient logistics plan and consignment. The proposed system is able to manage spatial objects in GIS as well as logistic information in the mobile environment. And for the efficiently managing and retrieving of transporting trajectory of logistics, we extend previous moving object indexing method, TB-Tree, to use multi-version framework and evaluate data updating performance. It is able to apply the proposed method to develop mobile contents services based on continuously changing location of moving object in the mobile environment.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.8
• /
• pp.1789-1798
• /
• 2012

IEEE 802.15.4a standard can provide a variety of location-based services for ZigBee or wireless network applications by adapting the time-of-arrival (TOA) ranging technique. The non-line-of-sight (NLOS) condition is the critical problem in the IEEE 802.15.4a networks, and it can significantly degrade the performance of the TOA-based localization. To enhance the location accuracy due to the NLOS problem, this paper proposes an energy-efficient low complexity localization algorithm. The proposed approach performs the ranging with the multicast method, which can reduce the message overhead due to packet exchanges. By limiting the search region for the location of the node, the proposed approach can enhance the location accuracy. Experimental results show that the proposed algorithm outperforms previous algorithms in terms of the energy consumption and the localization accuracy.

• The KIPS Transactions:PartD
• /
• v.10D no.1
• /
• pp.45-56
• /
• 2003

In the wireless environment, according to the development of technology, which is able to obtain location information of spatiotemporal moving object, the various application systems are developed such as vehicle tracking system, forest fire management system and digital battle field system. These application systems need the data model, which is able to represent and process the continuous change of moving object. However, if moving objects are expressed by a relational model, there is a problem which is not able to store all location information that changed per every time. Also, existing data models of moving object have a week point, which constrain the query time to the time that is managed in the database such as past or current and near future. Therefore, in this paper, we propose a data model, which is able to not only express the continuous movement of moving point and moving region but also process the operation at all query time by using shape-change process and location determination functions for past and future. In addition, we apply the proposed model to forest fire management system and evaluate the validity through the implementation result.

• Journal of Internet Computing and Services
• /
• v.12 no.2
• /
• pp.55-62
• /
• 2011

To make service location protocol of IETF which is to be used in the wide area network to discover the location of desired service when computing resources are connected to the network, and to support simless connectivity between wired and wireless network in service viewpoint, to support the diversity trend of service agents in WIF, it needs to improve SLP, so as to add Liaison Agent and Forwarding Agent with FAAdvert message that is to communicate in between those entities. LA entity confirms the location of service located in wide area network, and FA transfers service information. The usage of existing messages such as SrvRqst, SrvRply, AttrRqst, AttrRply, DAAdvert, SrvReg, SrvAck, SrvDeReg is same as ever in wide area service network. The behaviors of improved protocol is modeled into petri-net and prove that it is free of deadlock and live-lock by execution of the model.