• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.183-188
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• 2017

This paper is for the a study on home healthcare system for a patient using SAW Tag. This system is useful when there's a patient in home. Many patients are wounded in restroom. But restroom is very private place and nobody want to be disturbed here. The place where the patient is most injured in the house is the toilet, and it is the point where the privacy of the individual should be kept and the patient's condition should be checked and cope with in case of emergency. And using saw tag, we can calculate position and ID through reflected rf signal. Therefore we propose a general home healthcare system. The management system utilized a seat bed system to monitor at-home patients. The system mounts a bio-signal measuring unit on a toilet seat, measures a bio-signal from the bio-signal measuring unit, and the measured bio-signal is transmitted to the main server through the user's smart phone. With proposed system, we can expand operation area to silver town where many patients are cared. In this paper we developed sensor system and saw tag positioning system and showed the result.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.43-49
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• 2008

The Real Time Location System (RTLS) is very important in the ubiquitous society for real time tracking of men, high price assets, and logistics products. In this work, we developed an active RF system for RTLS and tested its performance. The RTLS system developed in this work was constructed of three active readers and one active tag. The small size tag developed in this work operated with a coin type battery. To make the tag smaller, we used an internal PCB antenna and a chip antenna. We tested the performance of the tag. To reduce the manufacturing cost of our RF system, we used low price RF transceiver CC2510 chip-set. The CC2510 chip-set provided RSSI(Received Signal Strength Indicator) signal which could be used to determine the distances between an active tag and three active readers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3694-3701
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• 2009

This paper suggests that location tracking system by RFID. It uses the location tracking and the authentication to entrance after inserts passive RFID tag into user Identification card. The readers periodically broadcast their signal, and then the readers understand where users are by analyzing them. In one of tracking systems, it is possible to detect the area where user had stayed for the longest time during moving according to signal power, to know user moved path and user next moving path. Also, it can be used in entrance authentication system in security area by using tag ID value which stored to backend server.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1882-1883
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• 2007

본 논문은 근거리무선통신을 포함한 위치서비스를 위한 무선통신응용분야에 적용될 수 있는 고신뢰 고정밀 무선위치인식기술 방법을 제안한다. 제안된 위치인식방법은 양방향통신을 통해 추정된 무선태그의 신호세기 및 시간차를 측정된 거리정보를 바탕으로 상대적 위치에 대한 확률적 계산을 수행하게 되며, 측정데이터의 부정확성으로 인한 위치측정의 오차를 줄일 수 있다. 또한 제안된 고신뢰 무선측위 코아 스택을 근거리무선네트워크 형성이 가능한 2.4 GHz ISM 협대역 밴드의 ZigBee 무선비콘 및 무선태그 디바이스들에 탑재하고 실증시험을 위하여 스마트 홈 실내 환경 아래에서 $1m\;{\times}\;1m$ 의 위치인지를 가능케 하는 위치인식시스템을 구현한다.

• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.149-157
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• 2011

Passive tags are inferior to active tags in processing efficiency, so they have difficulty in largevolume processing. The proposed protocol reduces the volume of computation in passive tags and, at the same time, improves authentication for enhanced safety and security. That is, different from existing RFID protocols that return the same value even if an error happens when the reader reads a tag, the improved RFID security protocol returns a new value using a re-counter and processes the computation part of a tag in the reader or in a back.end system. Even if the information of a tag is acquired by an malicious way, it is not actual information but encrypted information that is not usable. In addition, even if tag information is read in sequence, it is changed in each read, so the protocol is safe from Location Tracking.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.143-146
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• 2008

For tracing tag locations, a trajectories should be modeled and indexed in radio frequency identification (RFID) systems. The trajectory of a tag can be represented as a line that connects two spatiotemporal locations captured when the tag enters and leaves the vicinity of a reader. If a tag enters but does not leave a reader, its trajectory is represented only as a point captured at entry and we should extend the region of a query to find the tag that remains in a reader. In this paper, we propose an interval data model of tag's trajectory in order to solve the problem. For the interval data model. we propose a new index scheme called the IR-tree(Interval R-tree) and algorithms of insert and split for processing query efficiently. We also evaluate the performance of the proposed index scheme and compare it with the previous indexes.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.805-811
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• 2008

This paper presents a design of RFID(Radio Frequency Identification) tag antenna which is available for a vehicle's side mirror and directivity characteristics by mr body. The proposed Tag antenna is designed symmetrical structure to improve the broad bandwidth characteristic and the readable range. A proposed tag antenna($30\;mm{\times}24\;mm{\times}1\;mm$) has resonant frequency at 910 MHz and bandwidth is 780 MHz ($540\;MHz{\sim}1320\;MHz$). The chip impedance is the 16 - $j131\;{\Omega}$ and the complex conjugate impedance of commercial chip has been used for tag antenna design. In order to evaluate effects of tag antenna for side view mirror's permittivity as well as car body(conductor), radiation pattern characteristics and readable range have been calculated and measured. The optimized position for a vehicle's RFID system has been observed in the inside of a side mirror and the calculated results show good agreement with the measured results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.287-292
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• 2007

In this paper, a QT_ecfi algorithm is proposed for identifying all the tags within the identification range. The proposed QT_ecfi algorithm revises the QT algorithm, which has a memoryless property. In the QT_ecfi algorithm, the tag will send the remaining bits of their identification codes when the query string matches the first bits of their identification codes. When the reader receives all the responses of the tags, it knows which bit is collided. If the collision occurs in the last bit, the reader can identify two tags simultaneously without further query. While the tags are sending their identification codes, if the reader detects a collision bit, it will send a signal to the tags to stop sending. According to the simulation results, the QT_ecfi algorithm outperforms the QT algorithm in terms of the number of queries and the number of response bits.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1421-1424
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• 2009

RFID(Radio-Frequency IDentification) 시스템은 무선주파수를 이용한 자동 인식 기술로 개인의 위치 추적이나 사용자 프라이버시와 같은 정보 유출의 위험성을 내포하고 있다. 이러한 문제점을 해결하기 위해 대칭키 기반의 AES 암호화 알고리즘은 해시함수나 공개키 암호화 기법에 비해 메모리를 적게 소모하고 구현이 쉬운 장점 때문에 수동형 RFID태그에 더 적합하다. 그러나 기존의 AES를 이용한 RFID 인증 프로토콜에서는 항상 고정된 키를 이용하여 암호화하였고 태그와 리더사이의 안전하지 않은 무선 채널에서 공격자에 의해 키 값이 노출될 수 있는 또 다른 문제점을 가지고 있다. 본 논문에서는 태그와 서버의 고정된 키와, 리더 태그 서버에서 생성된 난수를 차례로 이용하여 대칭키를 변환한다. 그리고 매 세션마다 변환된 키로 난수를 암호화 하면서 태그와 리더를 상호 인증한다. 이와 같이 변환된 키를 이용할 경우 키 값의 노출 문제가 해결되며, 이 키를 통해 암호화하여 인증할 경우 재전송, 도청, 위치추적 및 스푸핑과 같은 공격에도 안전하다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.301-303
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• 2012

In this Paper, we are implemented position awareness system based on one-pass tag. This system are combined ZigBee and RFID technology. We developed the solution to detect of user's position using position awareness receiver and repeater. This location recognition includes parked car location tracking, coming in and out car, automation of immigration control, enhanced security through emergency call, and automatic invocation elevator control and etc.