• Title, Summary, Keyword: Location of Tags

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A hand-off mechanism of mobile nodes in a location positioning system based on ZigBee tags

  • Eun, Seong Bae;Chae, Yi Geun
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.2
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    • pp.175-181
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    • 2014
  • Location awareness is one of the key functions to build an U-city. Recently, many of works for the location-aware systems are emerging to be applied to on-going large-scale apartment complex. For example, when dwellers or cars with active tags are move in the apartment complex, the active tags broadcast their own identifiers periodically and receivers such that routers use this information to calculate the location of the active tags. Since the active tags can actually move between routers and coordinators, it requires a hand-off mechanism. In this paper, we investigate the hand-off problem occurred in location awareness system based on ZigBee active tags. We propose and analyze a new approach for handling the hand-off problem. Through a mathematical analysis, we show that our approach diminishes the quantity of packet transfer than ZigBee's approach.

The Modeling Scheme of RFID Tags for Processing Regional Queries

  • Kim, Dong-Hyun;Hong, Bong-Hee
    • Journal of information and communication convergence engineering
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    • v.6 no.1
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    • pp.110-116
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    • 2008
  • A RFID is an automatic data collection system based on the radio frequency and is the key technology of ubiquitous computing environments. Since the locations of objects attached by RFID tags can be acquired by readers, it is possible to query the locations of tags. To query tags efficiently, the data of RFID tags should be modeled and indexed. However, since the location information of tags, the predicates of queries, are differ from coordinates of moving objects, it is difficult to model tags under the concept of moving objects, In this paper, we propose the location model of tags to represents the trajectories of tags. The location model is composed of the set and graph based approaches.

The Proximity Scheme of the Perceptual Space for Indexing The Trajectories of Tags (태그 궤적 색인을 위한 인식공간 근접성 기법)

  • Kim, Dong-Hyun;Ahn, Swng-Woo
    • 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.

Design and Implementation of A Location Positioning System based on ZigBee Tags in Apartment (ZigBee 태그기반 아파트 위치인식시스템 설계 및 구현)

  • So, Sun-Sup;Eun, Seong-Bae
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.10
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    • pp.13-19
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    • 2007
  • Location awareness is one of the key functions to build U-city. Recently, many of works for location-aware systems are emerging to commercially apply to on-going large-scale apartment complex. As dwellers or cars being attached with active tags are moving in the U-city complex, the active tags periodically broadcast their own identifiers mu routers fixed along the street or in a building use those information to calculate location of thorn. There are several issues to be considered for such an environment. In this paper we propose i) a new architecture for location-aware system considering such issues ii) technical issues to implement it using active tags, and iii) a mathematical analytic model to investigate overall performance and verify it by comparing with actual experimental results. Through mathematical analysis, we can show that it is more efficient for the routers to send location signals than the tags do. We also show that there are several additional services available in the apartment complex. We conduscted several experiments hi a real ease parking lot to show that our system can locate the location of dwellers or cars.

Performance Analysis of Location-Aware System based on Active Tags (능동태그 기반 위치인식 시스템의 성능 분석)

  • So, Sun-Sup;Eun, Seong-Bae;Kim, Jin-Chun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.2
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    • pp.422-429
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    • 2007
  • Location awareness is one of the key functionalities to build an U-city. Recently, many of works of the location-aware systems are emerging to commercially apply to on-going large-scale apartment complex based on U-city. As dwellers or cars being attached with active tags are moving in the U-city complex, the active tags periodically broadcast their own identifiers and receivers fixed along the street or in building use those information to calculate location of them. There are several issues to be considered for such an environment. The first is that the number of active tags operating in the same region are large as much as tens of thousands, and the second is that the active tags should be alive without change of batteries more than a year, hence low power consumption is very important. In this paper we propose i) a new architecture for location-aware system considering such issues, ii) technical issues to implement it using active tags, and iii) a mathematical analytic model to investigate overall performance and verify it by comparing with actual experimental results. Through the analysis we can show the theoretical boundary of the lowest packet loss rate and the maximum number of tags with acceptable performance for the systems based on active tags. The results can be applied to practical design of location-based systems of U-City projects.

Design and Implementation of Robustness Distributed RTLS in Dense Environment (밀집 환경에 적합한 신뢰성 있는 분산형 RTLS 시스템의 설계 및 구현)

  • Jang, Hyun-Sung;Choi, Hoon;Jung, Yeon-Su;Baek, Yun-Ju
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.2B
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    • pp.287-295
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    • 2010
  • RTLS used to track the location of object or person in real time. However, if there are a lot of tags and readers, the conventional single RTLS server may fail to estimate location of tags. And if the server cannot receive the tags signal due to pass-loss or NLOS from more than three readers, the server fail to estimate location of tags. In this paper, we propose a special reader which embeds RTLS location engine for distributed RTLS. And by using multi-directional antenna, alleviating multi-path effect and allowing estimate tag's location only using two readers. We also implement the system, we can reduce server packet 16times and get the all results of location estimate in single second. We achieved the location error within 1m.

Design of ULID-based Location-Sensing Service Model (ULID 기반 위치 인식 서비스 모델의 설계)

  • Nam, Kwang-Woo
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.4
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    • pp.143-154
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    • 2005
  • This paper proposes the location acquisition methods and LBS(location-based services) system using RFID(radio frequency identification) tags with location information in ubiquitous city. Location information is checked using RFID tags attached to various buildings. stores and road signs. And various LBSs are provided based on the location information. Traditionally, when the location information is obtained by a GPS, the precision of the location information may deteriorate due to geographical displacement of a satellite and GPS receivers, for example shadow zone by building, in-door environment, and heavy cloud. The objective of this paper is to provide a ULID(universal location identification) data structure, a ULID-based location acquisition method and an LBS system, in which precise location information is extracted using RFID tags attached to various buildings, stores and road signs and ULID and also danger of information leakage is minimized so that an LBS of ubiquitous environment can be provided to a user.

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Advanced Indoor Location Tracking Using RFID (RFID를 이용한 개선된 실내 위치 추적)

  • Joo, Won-lee;Kim, Hyo-Sun;Jung, Yeong-Ah;Hong, Yeon-Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.1
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    • pp.425-430
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    • 2017
  • RFID is a technology that uses radio frequency to read information in tags attached to objects or people. Because it reads the information without contact when tracking the location using tags in a RFID system, there can be errors between the actual position and measured position. In this paper, three methods (the method of radiation pattern, the method of the median value, and the method using both the radiation pattern and median value) are proposed to identify the location of objects or people using the RFID technique. The location identification system based on RFID was constructed and tags were arranged in a square pattern. The real location and experimentally predicted location of an object containing a reader were compared to confirm the error. Instead of the existing papers that obtained the approximately location of a reader by calculating the center of gravity of all tags read by that reader, in this study, the predicted location was obtained by the median value and the radiation pattern. This study validated which method was the most efficient among the three methods proposed in this paper through the data of the read tags. As a result, the method of the median value had the smallest error among those assessed.

TDOA-Based Localization Algorithms for RFID Systems Using Benchmark Tags (벤치마크 태그를 이용한 도착시간 차 기반의 RFID 측위 알고리즘)

  • Joo, Un Gi
    • Korean Management Science Review
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    • v.29 no.3
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    • pp.1-11
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    • 2012
  • This paper considers a localization problem in time difference of arrival (TDOA)-based radio frequency identification (RFID) systems. To estimate the position of a target tag, this paper suggests three localization algorithms that use benchmark tags. The benchmark tags are the same type as the target tag, but either the locations or distance of the benchmark tags are known. Two algorithms use the benchmarks for auxiliary information to improve the estimation accuracy of the other localization algorithms such as least squared estimator (LSE). The other one utilizes the benchmarks as essential tags to estimate the location. Numerical tests show that the localization accuracy can be improved by using benchmark tags especially when an algorithm using the LSE is applied to the localization problem. Furthermore, this paper shows that our benchmark algorithm is valuable when the measurement noise is large.