• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.41-42
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• 2008

무선방식으로 원격에서의 인식으로 정보교환을 가능하게 하는 RFID(Radio Frequency IDentification) 시스템은 태그 내의 배터리 유무에 따라 수동형과 능동형으로 구분된다. 수동형 태그는 판독기로부터 받은 RF 신호를 에너지로 이용하기 때문에 인식거리가 짧으며, 가격이 싸고 반영구적으로 사용할 수 있는 장점이 있다. 반면에, 능동형 태그는 금속재질에 취약한 수동형의 단점을 극복하는 동시에 인식거리가 길고, 인식률이 좋은 장점이 있다. 따라서 항만물류나 국방 분야에서 능동형 RFID 시스템에 대한 개발이 점차 확대되고 있다. 하지만 동일한 표준으로 개발된 제품의 서로 간에 인식이 불가능한 사례가 보고되고 있으며, 국제적으로 정확한 평가방법 및 장치가 정립되지 않아 개발된 제품들 간의 상호 운용성 및 표준 적합성 평가에 대한 어려움이 존재한다. 본 논문에서는 능동형 RFID 시스템의 적합성 평가를 위한 에뮬레이터의 하드웨어 및 소프트웨어를 설계하고 제작하였다. 설계된 장치는 Matlab의 Simulink를 통한 시뮬레이션으로 성능을 분석하였고, 실제 능동형 RFID 태그의 표준적합성 평가를 통해 에뮬레이터의 적용 가능성을 검증하였다.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.453-456
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• 2006

본 논문은 유비쿼터스 컴퓨팅 시대를 열어가는 유비쿼터스의 핵심 기술인 RFID 시스템의 구성요소 중 하나인 Type B RFID 태그를 설계하였다. RFID 태그는 전원공급 여부에 따라 능동형과 수동형으로 구분한다. 본 논문에서는 현재의 IT분야에서의 RFID 시장과 연구동향에 맞춰 수동형 Type B RFID 태그의 Digital 파트를 설계하고, 성능을 검증하였으며, 향후 RFID 시스템의 연구방향에 대해서도 제시하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.5
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• pp.46-51
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• 2013

In this paper, a dual-band antenna is proposed for the RF power harvester system as well as RFID tag. The proposed antenna operates as the passive and active RFID tag antenna in the UHF and microwave band, respectively. In addition, to charge the battery of an active RFID tag in the microwave band, it harvest the RF signal for tagging from the passive RFID tag antenna in the UHF band. The proposed antenna operates in the UHF band (917~923.5 MHz) and microwave band (2.4~2.45 GHz). In order to obtain the dual-band operation, the dipole structure and meander parasitic elements are proposed as the ${\lambda}/2$ and $1{\lambda}$ dipole antenna, respectively. The radiating dipole structure in the microwave band acts as the coupled feed for the meander parasitic elements in the UHF band. The impedance bandwidth (VSWR < 2) of the proposed antenna covers 917~923.5 MHz (UHF band) and 2.4~2.45 GHz (Microwave band). Measured total efficiencies are over 45 % in the UHF band and over 70 % in the microwave band. Peak gains are over 0.18 dBi and 2.8 dBi in the UHF and microwave band with an omni-directional radiation pattern, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.822-829
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• 2009

A reader protocol is an interface between a host and RFID readers. There are several standards for reader protocol such as EPCglobal Low Level Reader Protocol (LLRP) 1.0.1, EPCglobal Reader Protocol (RP) 1.1, and ISO/IEC 15961/15962. Unfortunately, these standards focus on the passive RFID system, and so they are not appropriate for the active RFID system. In this paper, we implemented an efficient reader protocol for the active RFID system, which is based on EPCglobal LLRP 1.0.1, but smoothing/filtering functions of EPCglobal RP 1.1 are added. This protocol is designed to configure air interface parameters for active RFID readers and tags. It can reduce the amount of data transfer between the reader and host by filtering function, and can improve the performance of tag collection by smoothing function. In addition, it can remove inefficiency caused by tag memory data change according to the standards of ISO/IEC 15961/15962. In the real-world environment, we evaluated the performance of our implemented reader protocol using one RFID reader and 45 tags.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.747-754
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• 2013

This paper proposed a new transponder detection method to reduce tag recognition time and simplify anti-collision process in RFID systems. In conventional systems, a transponder in detectable area is passively recognized by responding to a reader command. In addition, if there are multiple tags in the area, a collision between tags occurs by responding at the same time to a command and anti-collision process begins. In the proposed method, tags are actively recognized without any command from a reader which results to reducing a tag recognition time and simplifying anti-collision process. To compare transponder recognition time, the process of transponder recognition in conventional systems is analysed. A circuit to detect transponder directly is developed and antenna voltage variation of a reader in the appearance of multiple transponders is analysed for the implementation of the proposed method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.872-879
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• 2010

This paper describes the design for radiation pattern directivity of vehicle license plate RFID tag antenna to improve the readable range. Directivity pattern of the proposed passive antenna is decided by the meander line position and the bumper size attached to the tag antenna. In order to prove the verification of the calculated directivity pattern and readable range of the proposed antenna, the tag antenna has been fabricated and measured at the anechoic chamber. It is shown that the maximum directivity gain of the measured radiation pattern of active and passive tag antenna were observed 2.32 dBi and 3.1 dBi, respectively. The maximum readable range of passive tag antenna was measured about 8.5 m at ${\pm}45^{\circ}$ beam direction on the basis of the driving car direction($0^{\circ}$ of azimuth angle).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.95-98
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• 2009

RFID(Radio Frequency IDentification) technology is an automatic identification method using radio frequencies between RFID reader which collects the informatin and tag which transmits the information. RFID technology develops passive RFID which transmit the only ID to active RFID which transmit the additional information such as sensing information. there is ISO/IEC 18000-7 as typical standard of active RFID. it is single channel system of 433.92MHz and has limitation of collection of a number of tags. to overcome limitation of collection of many tags, we propose the new 2.4GHz active RFID technology which can use the multi-channel. if reader has multi-interface and uses another channel in each, reader could fast collect the tags. but, if a reader which has many interfaces collects tags through the specific interface, the performance may not improve any more comparing with a reader using single interface. in this paper, we show the fast collection through design and implementation of protocol for load balancing between interfaces in multi-interface RFID reader.

• 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.

• Electronics and Telecommunications Trends
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• v.22 no.3 s.105
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• pp.29-37
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• 2007

RFID 기술은 반도체 기술의 발전과 인터넷의 등장으로 인하여 지난 10여 년 동안 꾸준한 발전을 해왔으며 유통, 물류, 의료, 교육 등 다양한 분야에 적용되고 있다. 이는 향후 수 년 내에 거의 모든 물품에 태그를 부착하게 됨에 따라 유비쿼터스 환경 구축에 큰 기여를 할 것으로 기대된다. 이러한 RFID 기술은 저주파(LF), 고주파(HF), 초고주파(UHF) 및 마이크로파(M/W) 대역의 무선전파를 사용하며 각 대역의 전파 특성에 따라 동물추적, 교통카드, 물품관리, 전자화폐 등 다양한 분야에 선택적으로 적용되고 있으며, 단말기의 형태에 따라 고정형, 휴대형, 모바일 RFID 기술로 분류되고 최근에는 택시안심귀가서비스 등 휴대폰에 RFID 리더 기능이 결합된 모바일 RFID 서비스도 시범서비스를 선보이면서 우리 생활에 파고들고 있다. 또한 항만물류 관리 등과 같이 긴 인식거리가 필요한 능동형 RFID 기술을 포함하여 많은 연구와 실증실험, 시범서비스나 본사업이 이루어지고 있으며 최근에는 파렛, 케이스 단위가 아닌 물품 단위에 태그 부착을 위한 ILT 기술도 속속 선보이고 있다. 본 고에서는 시장전망이 가장 밝은 것으로 알려진 UHF 대역을 중점으로 RFID 기술을 살펴보고 이중에서도 모바일 RFID 기술을 포함한 수동형 RFID 기술, 능동형 RFID 기술 및 이와 관련한 표준화 동향을 알아본다.이를 활용한 응용 시스템에 대하여 간략히 살펴볼 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.618-630
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• 2011

Mobile RFID system, that consists of the existing RFID reader mounted on the mobile devices such as smartphones, is able to provide the users a variety of services and convenience. Although the users can get the information about a certain product anytime anywhere, there is high probability that their privacy may be violated because their belongings with RFID tags can be scanned by other mobile readers at any time. Several RFID authentication schemes have been proposed to deal with these privacy issues. However, since the existing solutions require heavy computation on the tag side, most of them is not applicable to the general low-cost passive tags which do not have any processing unit. In this paper, we propose the efficient authentication scheme for mobile RFID system applicable to the passive tags as well as the active ones by the best use of computing capability of mobile devices. The proposed scheme satisfies the import security issues such as tag protection, untraceability, anti-traffic analysis. We also implement the proposed scheme on top of real smartphone for feasibility and show the experimental results from it.