• Electronics and Telecommunications Trends
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• v.22 no.3 s.105
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• pp.38-45
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• 2007

최근 각광을 받고 있는 RFID 기술은 기존의 바코드를 대체하여 상품 관리를 네트워크화 및 지능화 함으로써 유통 및 물품 관리뿐만 아니라 보안, 안전, 환경 관리 등에 혁신을 선도할 것으로 전망되며, 이전에 존재하지 않았던 거대한 새로운 시장을 형성할 것으로 기대된다. 이러한 RFID 기술은 사물의 고유한 ID를 단순히 인식하는 읽는 기능중심에서 사물의 이력 정보를 관리할 수 있는 읽고 쓰기 기능, 그리고 전자 태그들이 자신의 고유 정보뿐만 아니라 온도, 습도, 압력 등 주변의 정보까지 감지하는 센싱 기능을 가지도록 발전할 것이다. 이와 같이 기존의 ID 획득만 가능한 태그에 외부 환경 정보를 습득할 수 있는 센서와 자체 전원 공급을 위한 박형 전지(film battery)가 추가된RFID 태그를 ‘센서 태그(smart active label 혹은 RFID sensor tag)’라고 부르며, 그방식은 크게 반능동형 방식(semi-passive 혹은 semi-active)과 능동형 방식(active)으로 구분된다. 본 고에서는 현재 국내외에서 활발히 연구 개발되고 있는 반능동형 센서 태그 기술 동향과 센서 태그 관련 국제 표준화 동향에 대해서 알아본다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1034-1039
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• 2005

SALM(Simultaneous localization and mapping) and AI(Artificial intelligence) have been active research areas in robotics for two decades. In particular, localization is one of the most important tasks in mobile robot research. Until now expensive sensors such as a laser sensor have been used for mobile robot localization. Currently, the proliferation of RFID technology is advancing rapidly, while RFID reader devices, antennas and tags are becoming increasingly smaller and cheaper. So, in this paper, the smart floor using passive RFID tags is proposed and, passive RFID tags are mainly used for identifying location of the mobile robot in the smart floor. We discuss a number of challenges related to this approach, such as tag distribution (density and structure), typing and clustering. In the smart floor using RFID tags, the localization error results from the sensing area of the RFID reader, because the reader just knows whether the tag is in the sensing range of the sensor and, until now, there is no study to estimate the heading of mobile robot using RFID tags. So, in this paper, two algorithms are suggested to. The Markov localization method is used to reduce the location(X,Y) error and the Kalman Filter method is used to estimate the heading($\theta$) of mobile robot. The algorithms which are based on Markov localization require high computing power, so we suggest fast Markov localization algorithm. Finally we applied these algorithms our personal robot CMR-P3. And we show the possibility of our probability approach using the cheap sensors such as odometers and RFID tags for mobile robot localization in the smart floor

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.1
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• pp.68-75
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• 2007

A single chip NFC transceiver supporting not only NFC active and passive mode but also 13.56MHz RFID reader and tag mode was designed and fabricated. The proposed NFC transceiver can operate as a RFID tag even without external power supply which has dual antenna structure for initiator and target. The area increment due to additional target antenna is negligible because the target antenna is constructed by using a shielding layer of initiator antenna. The analog front end circuit of the proposed NFC transceiver consists of a transmitter and receiver of reader/writer block supporting NFC initiator or RFID reader mode, and a tag circuit for target of passive NFC mode or RFID tag mode. The maximum baud rate of the proposed NFC device is 212kbps by using UART serial interface. The chip has been designed and fabricated using a Magnachip's $0.35{\mu}m$ double poly 4-metal CMOS process, and the effective area of the chip is 2200um by 3600um.

• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.63-72
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• 2002

In Korea, a need of automatic dairy farm management system has been increased to lower production cost and to strengthen international competition. However, the present management system was mostly relied on foreign technologies and caused some problems in post management and after-sales services. Therefore, though there is a problem of price and quality at present, domestic technologies of the management system should be developed for the long run. This study was conducted to develop an electronic identification unit for an automatic dairy farm management system. The developed system was consisted of a tag, a reader, a switching circuit, and a personal computer. The tag attachable to each individual cow was developed to transmit individual radio frequency(RF) code into the air with modulation of ASK(amplitude shift keying). And the switching circuit was added to avoid confusion on reception and transmittance. The reader attached to a feeding device was developed to transmit activating signal periodically and to identify code of the individual tag when the tag was approached to the device. The reader was consisted of an active filter, a detecter, a comparator and a microcontroller. The test result was feasible enough to apply it for the automatic farm management system and the identified maximum distance was about 37cm.

• 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 Information Science Society Conference
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• 2010.06a
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• pp.236-237
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• 2010

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.407-409
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• 2012

기존 IP-USN 및 RFID 기술의 장점을 접목시킨 Active IP-RFID 기술은, IP 인프라와 IP-USN과 RFID 인프라 간 시너지 효과를 극대화하기 위해 RFID 태그에 IP를 탑재하여 확장성과 이동성을 보장하고 태그의 직접적인 관리 및 제어도 가능하게 하는 기술이다. 본 논문에서는 Active IP-RFID 시스템이 Semi-Mobility 기반에서 IP-TAG가 적은량의 에너지를 사용하여 보다 장시간 통신을 하기위한 Advanced Low Power Listening 기법을 제안하고, Always On 방식과 제안한 Advanced Low Power Listening 기법의 전류 소모 차이를 비교하였다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.32-43
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• 2004

RFID 시스템에서 태그는 리더와 전자기 에너지 교환에 의해 동작을 하며 배터리를 사용하는 active 형 태그와 배터리를 사용하지 않는 passive형 태그로 크게 구분된다. 또한 태그는 자체 회로구조에 의해 harmonic 태그, anharmonic 태그, sequenced amplifier 태그로 나뉜다. Passive 태그에서는 리더의 반송파 backscatter 방식을 이용하여 동작을 하며 active 태그는 자체 발진회로에 의해 태그정보를 송신한다. 태그의 변조방식으로 PSK, FSK, ASK 등을 사용하며 변조방법에 따라 회로 구성과 프로토콜 설계가 달라진다. 또한 리더의 전파 신호를 정류하기 위하여 렉테나(rectenna)가 필요하다. 본 논문에서는 태그의 분류, 동작, 구조 등에 관한 일반적인 내용을 기술하였다. 특히 UHF 대역 이상의 태그 기술 최근 추세가 안테나 부분을 제외하고 CMOS one chip화 하는 수준으로서 900 MHz UHF 대역, 2.45 GHz RFID 칩이 상용화 되어 있다. 칩의 내부구조와 태그의 변조방식에 의거한 동작에 관한 개괄적인 내용을 서술하였다.

• Journal of Dairy Science and Biotechnology
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• v.29 no.1
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• pp.49-54
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• 2011

Bile salt hydrolase (BSH, EC 3.5.1.24) activity, which cleaves amide bond between carboxyl group (bile acid) and amino group (glycine or taurine), is commonly detected in gut-associated species of human and animal. During the screening of BSH active strains from the fecal samples of elderly human volunteers, strain CU30-2 was isolated on the basis of the highly active BSH producing activity. A bsh gene of the isolate was cloned into the pET22b expression vector and overexpressed in Escherichia coli BL21 (DE3) Gold by induction with 1mM IPTG. The overexpressed BSH enzyme with 6x His-tag was purified with apparent homogeneity using a $Ni^+$-NTA agarose column and characterized. The BSH enzyme of E. faecalis CU30-2 exhibited approximately 50 times higher activity against glycol-conjugated bile salts than tauro-conjugated bile salts having the highest activity against glycocholic acid. Considering the prevalence of E. faecalis strains in the human GI tract and glycol-conjugates dominated bile acid composition of human bile, further study is needed to investigate the impact of the BSH activity exerted by E. faecalis strains to the host as well as to the BSH producing strains.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.330-336
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• 2005

Lactococcus lactis A164 is a nisin Z-producing strain isolated from kimchi. Its antimicrobial spectrum has been found to be active against most Gram-positive bacteria tested, yet inactive against Gram-negative bacteria [3]. Accordingly, to overcome this drawback, the current study attempted to express human $\beta$-defensin-l (hBD-l), which kills both Gram-positive and Gram-negative bacteria in L. lactis AI64. When the hBD-l cDNA was introduced using a nisin Z-controlled expression cassette, the L. lactis A164 transformants grew very poorly, due to the bactericidal effect of the expressed hBD-l against the transformants. Therefore, a gene fusion system was designed to reduce the toxicity of the expressed heterologous protein against the host cells. As such, the hBD-l gene was fused to the DsbC- Tag of pET -40b(+), then introduced to L. lactis A 164. The transformants expressed an intracellular 35.6-kDa DsbC-hBD-l fusion protein that exhibited slight activity against the host cells, yet not enough to strongly inhibit the cell growth. To obtain the recombinant hBD-l, the DsbC-hBD-l fusion protein was purified by nickel-affinity column chromatography, and the DsbC-Tag removed by cleaving with enterokinase. The cleaved mature hBD-l exhibited strong bactericidal activity against E. coli JM109, indicating that the recombinant L. lactis A 164 produced a biologically active hBD-I. In addition, the recombinant L. lactis A 164 was also found to produce the same level of nisin Z as the wild-type.