• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.82-84
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• 2004

최근 유비쿼터스 환경에서 객체에 태그를 장착하여 위치를 추적하는 응용분야가 늘어가고 있는 추세이며, 이러한 응용에서 빈번히 사용되는 질의는 객체의 위치를 찾는 find와 특정 위치의 객체를 찾는 look질의가 있다. 두 질의에서 처리되는 데이터는 시간과 공간을 포함한 다차원 대용량 데이터이며 과거 및 현재 상태의 검색을 지원해야 하므로 효율적인 질의 처리를 위해서는 태그 객체를 위한 새로운 데이터 모델과 색인이 필요하다. 본 논문에서는 태그 객체를 간격 데이터로 정의하고 과거 및 현재 데이터에서 find와 look질의를 처리할 수 있는 색인 구조를 제안한다. 제안하는 색인에서 노드에 오버플로우가 발생할 경우 새로운 단말 노드 분할 정책을 사용하여 분할하며 성능 평가를 통해서 기존 정책보다 우수함을 증명한다.

• Journal of Korea Multimedia Society
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• v.9 no.3
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• pp.307-314
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• 2006

This paper proposes a QT_rev algorithm for identifying multiple tags. The proposed QT_rev algorithm is based on the query tree algorithm. In the algorithm, the tag will send all the bits of their identification codes when the query string matches the first bits of their identification codes. On the other hand, in the QT_rev algorithm, the tag will send the remaining bits of their identification codes. After the leader receives all the responses of the tags, it knows which bit is collided. Therefore, if the collision occurs in the last bit, the reader can identify two tags simultaneously without further query. According to the simulation results, the QT_rev algorithm outperforms the QT algorithm in terms of the number of queries and the number of response bits.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4A
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• pp.431-439
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• 2006

RFID Anti-Collision technique is needed to avoid collision problem caused by Radio interference between tags in the same RFID Reader area. It affects the performance and reliability of the RFID System. This paper propose the QT-CBP(Query Tree with Collision-Bit Positioning) Algorithm based on the QT(Query Tree) algorithm. QT-CBP Algorithm use precise collision bit position to improve the performance. We demonstrated the proposed algorithm by simulation. Our algorithm outperformed when each tag bit streams are the more duplicate and the number of tags is increased, compared with QT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.909-914
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• 2012

The paper introduces the RFID location based Tree Management System (TMS) using UHF RFID tag and GPS. The bolt shape tag has been developed since the wood material has high dielectric constant. Since the characteristics and impedance of tag antenna can be changed by the material next to the tag, the plastic bolt shape tag antenna has to be carefully designed with consideration of the high dielectric constant of the wood material. The RFID TMS system has been utilized with the bolt shape tag antenna and GPS. The TMS system uses and links Google map to locate the location of the trees. Therefore, this system allow us to manage the trees economically and efficiently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12A
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• pp.966-974
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• 2011

In this paper, we propose an asset tracking system for applying a container port environment. If we attempt to apply this common locating system to a port environment for logistics automation, the system performance is degraded because there are many steel obstacles that cause interference in the RF communication and measurement. We divided readers into two types - fixed and mobile readers; hence, the location method operates in two steps for efficient wireless communication and precise measurement. In addition, the system estimates the location with trajectory information of assets when the small number of measurement is gathered. We implemented all the system components and installed these at a real port for evaluation. The success rate of communication and estimation is much better than that of the existing general locating system, and the location precision is substantially increased.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1201-1204
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• 2005

차세대 유비쿼터스 환경에서 중요한 기술적 위치를 차지할 것으로 예상되는 무선주파수 인식기술(RFID)은 다양한 분야에서 적용될 것으로 기대가된다. 하지만 핵심이 되는 태그 자체의 특성으로 인하여 사용자의 프라이버시 침해라는 역기능도 내포하고 있다. 따라서 본 논문에서는 이러한 RFID 태그 사용자의 정보 누출에 의한 프라이버시 보호를 위하여 기존의 암호학적 보호기법을 적용하기 어려운 저가의 태그를 이용한 RFID시스템 환경에서 효율적으로 태그의 정보를 보호하는 기법인 블록커 태그를 이용하였다. 블로커 태그는 보호하고자하는 태그의 정보를 알아내고자 하는 공격자의 요청에 대하여 실제 태그와 같은 정보로 응답하되 특정 태그정보가 아닌 전체 태그 정보를 전달하는 형태로 공격자가 특정 태그 정보를 찾지 못하게 하여 사용자의 프라이버시 보호가 가능함을 보였다.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.2
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• pp.164-172
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• 2008

This paper presents the efficient localization of a mobile robot traveling on the floor with tags installed, using the spatial and temporal information acquired from passive RFID environment. Compared to previous research, the proposed localization method can reduce the position estimation error and also cut down the initial cost tag installation cost. Basically, it is assumed that a mobile robot is traveling over a series of straight line segments, each at a certain constant velocity, and that the number of tags sensed by a mobile robot at each sampling instant is at most one. First, the velocity and position estimation of a mobile robot starting from a known position, which is valid for all segments except the first one. Second, for the first segment in which the starting position is unknown, the velocity and position estimation is made possible by enforcing a mobile robot to traverse at least two tags at a constant velocity with the steering angle unchanged. Third, through experiments using our passive RFID localization system, the validity and performance of the mobile robot localization proposed in this paper is demonstrated.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.211-217
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• 2019

Location positioning systems are available in applications such as mobile, robotic tracking systems and Wireless location-based service (LBS) applications. The GPS system is the most well-known location tracking system, but it is not easy to use indoors. The method of radio frequency identification (RFID) location tracking was studied in terms of cost-effectiveness for indoor location tracking systems. Most RFID systems use active RFID tags using expendable batteries, but in this paper, an inexpensive indoor location tracking system using passive RFID tags has been developed. A pattern matching method and a system for tracing location by generating regression curves were studied to use precision tracking algorithms. The system was tested by verifying the level of error caused by noise. The three-dimensional curves are produced by the regression equation estimated the statistically meaningful coordinates by the differential equation. The proposed system could also be applied to mobile robot systems, AGVs and mobile phone LBSs.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.595-600
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• 2006

Nowadays, low-cost radio frequency identification (RFID) technique, is recognizable without the physical contact between the reader and the tag, has been attracting more and more interests from both industry and academic institutes. however, it causes the serious privacy infringement such as excessive information exposure and user's location information tracking due to the wireless characteristics. The security problem of read only tag can be only solved by physical method. In this paper, we propose a low-cost authentication protocol which can be adopted for read-only RFID tag using XOR and Partial ID. The proposed protocol is secure against reply attacking, eavesdropping and spoofing attacking so that avoiding the location privacy exposure

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.377-383
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• 2004

In this paper, we propose an application model of RFID that needs not be worried about battery degradation problems and offers convenience of hand-carry. We design the RFID application model which can track medium distance target RFID Tag and detect the signal difference between multi-detectors in a room area using 900MHz frequency band. In the case of multi-ID Tag in one detector, we approach TDMA scheme.