• 천문학회보
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• 제39권2호
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• pp.68.2-68.2
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• 2014

High Frequency Peakers (HFPs) are radio-loud Active Galactic Nuclei (AGN), which are regarded as being in the earliest evolutionary phase (102-103 years) of radio galaxies. They are expected to be small in size (< ~1 kpc) compared to their host galaxies (~a few 10s kpc), and have convex spectra, which are peaking at high radio frequency (> 5 GHz). Their size and spectral shape are the most obvious supporting evidence of extremely young ages. HFPs are therefore ideal targets to probe the earliest stage of radio sources. To date however, the young radio source classification has been relying mainly on the spectral shape which usually does not cover high enough frequencies where the true peak flux is located. Hence HFPs are often confused with blazars which may show a similar spectral shape and apparent compactness but are a somewhat evolved form of AGNs. Therefore, we have been challenging to identify HFPs among the sample of 19 candidates using the Korean VLBI Network (KVN) which enables us to extend the radio spectrum baseline up to 22 and 43 GHz. These are higher than the frequencies used in most previous studies of HFPs, allowing us to select genuine HFPs. By long-term monitoring of 18 epochs, we have also inspected the variability of the sample to select out blazars which are highly variable yet with a similar radio spectrum. In this work, we present the light curves and spectral properties of the HFP candidates. We discuss the results of our re-identification of HFPs.

• 한국군사과학기술학회지
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• 제16권4호
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• pp.414-421
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• 2013

In this paper, a novel IFF(Identification of Friend and Foe) landmine system has been designed and fabricated using RFID(Radio Frequency Identification) wireless communication system. The IFF landmine system is composed of RECOMS(Remote Controlled Munition System), RFID reader and RFID tag. When the friendly forces have been identified by RFID wireless communication, the IFF landmine is unloaded automatically and indicates the warning message to the operator. Through the discussion, the detailed designs and the test results of identification distance have been described and antenna revision plans for improving the performance have been mentioned.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.637-640
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• 2003

무선인식기술은 제품에 부착된 칩의 정보를 주파수를 이용해 읽고 쓸 수 있는 무선주파수인식으로 사람, 상품, 차량 등을 비 접촉으로 인식하는 기술이다. 이러한 무선인식관련 기술의 급격한 발달로 RFID(Radio Frequency IDentification) 시스템이 기존 바코드 중심의 상품식별시스템을 대체할 것으로 판단되므로 이에 대한 무선인식 구성과 기능, 적용분야, 표준화 등을 검토하기로 한다.

• 대한안전경영과학회지
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• 제8권3호
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• pp.159-170
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• 2006

This paper deals with the S/W development of web-based warehouse management system using ubiquitous RFID(Radio Frequency Identification). This S/W System supports the realtime inventory management and collaborative operations of relational companies in SCM. We expect to decrease the logistic cost and to upgrade the status of WMS and competitive power of company.

• 한국통신학회논문지
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• 제32권4A호
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• pp.358-364
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• 2007

RFID(Radio Frequency IDentification) 기술은 라디오 주파수를 사용하는 비접촉 자동인식 기술이다. 이런 RFID 기술의 확산을 위해서는 리더(reader)가 다수의 태그(tag)를 짧은 시간 안에 인식하는 다중 태그 식별 문제를 해결 해야만 한다. 지금까지 이 문제를 해결하기 위한 충돌 방지(anti-collision) 알고리즘이 많이 개발되었고 이것들은 크게 알로하(ALOHA) 기반 알고리즘과 트리(tree) 기반 알고리즘으로 나뉜다. 본 논문에서는 이 두 가지 방법의 특징을 혼합한 새로운 충돌 방지 알고리즘 2가지를 제안한다. 그리고 대표적인 충돌 방지 알고리즘인 18000-6 Type A, Type B, Type C, query tree 알고리즘과 성능 비교 및 평가를 한다.

• 대한원격탐사학회지
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• 제40권2호
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• pp.219-228
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• 2024

Vessels can operate with their Automatic Identification System (AIS) turned off, prompting the development of strategies to identify them. Among these, utilizing satellites to collect radio frequency (RF) data in the absence of AIS has emerged as the most effective and practical approach. The purpose of this study is to develop a matching algorithm for RF with AIS data and find the RF's applicability to classify a suspected ship. Thus, a matching procedure utilizing three RF datasets and AIS data was employed to identify ships in the Yellow Sea and the Korea Strait. The matching procedure was conducted based on the proximity to AIS points, ensuring accuracy through various distance-based sections, including 2 km, 3 km, and 6 km from the AIS-based estimated points. Within the RF coverage, the matching results from the first RF dataset and AIS data identified a total of 798 ships, with an overall matching rate of 78%. In the cases of the second and third RF datasets, 803 and 825 ships were matched, resulting in an overall matching rate of 84.3% and 74.5%, respectively. The observed results were partially influenced by differences in RF and AIS coverage. Within the overlapped region of RF and AIS data, the matching rate ranged from 80.2% to 98.7%, with an average of 89.3%, with no duplicate matches to the same ship.

• 한국전자통신학회논문지
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• 제8권6호
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• pp.923-931
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• 2013

RFID(Radio Frequency Identification)는 버스카드, 출입문 카드, 물류유통, 건축자재 관리 등 일상생활에서 다양하게 사용되는 태그의 일종으로 ID정보를 무선 주파수(RF, Radio Frequency)를 사용하여 인식하는 무선인식장치이다. RFID는 투과성과 인식률, 메모리 크기, 다중태그 인식률, 외부 오염 먼지, 외부 충격 등에 따라 크기와 성능이 달라지고, 이와 같은 요소들을 고려한 RFID 보호를 위한 패키징이 필요하다. 현재 RFID는 건축자재의 효과적인 관리를 위해서도 다양하게 사용되고 있는데, 건축자재에 RFID를 부착하기 위해서는 외부로 부터의 충격에 강건한 건축자재용 RFID 패키징 제작이 요구되고 있다. 본 논문에서는 외부 충격에 강하고, 고장 시 RFID의 교체가 가능하도록 패키징 틀과 본체를 분리하여 설계된 건축자재용 RFID 패키징을 제안한다. 제안된 RFID 패키징을 위한 상세한 설계도를 제시하였으며, 3D 프린터를 사용하여 설계된 패키징을 직접 제작하여 성능 평가를 실시하였다.

• Journal of information and communication convergence engineering
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• 제10권1호
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• pp.33-39
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• 2012

In this paper, we compare the accuracy of most representative radio frequency identification (RFID) tag estimation functions in the context of minimizing RFID tag identification delay. Before the comparisons, we first evaluate the accuracy of Schoute's estimation function, which has been widely adopted in many RFID tag identification processes, and show that its accuracy actually depends on the number of tags to be identified and frame size L used for dynamic frame slotted Aloha cycles. Through computer simulations, we show how the accuracy of estimation functions is related to the actual tag read performance in terms of identification delay.

• Journal of Communications and Networks
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• 제14권1호
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• pp.10-14
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• 2012

When tag privacy is required in radio frequency identification (ID) system, a reader needs to identify, and optionally authenticate, a multitude of tags without revealing their IDs. One approach for identification with lightweight tags is that each tag performs pseudo-random function with his unique embedded key. In this case, a reader (or a back-end server) needs to perform a brute-force search for each tag-reader interaction, whose cost gets larger when the number of tags increases. In this paper, we suggest a simple and efficient identification technique that reduces readers computation to $O$(${\sqrt{N}}$ log$N$) without increasing communication cost. Our technique is based on the well-known "meet-in-the-middle" strategy used in the past to attack symmetric ciphers.

• Transactions on Electrical and Electronic Materials
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• 제11권1호
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• pp.20-23
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• 2010

The analog front end (AFE) of a radio frequency identification transponder using the ISO 14443 type A standard with a 100% amplitude shift keying (ASK) modulation is proposed in this paper and verified by circuit simulations and measurements. This AFE circuit, using a 13.56 MHz carrier frequency, consists of a rectifier, a modulator, a demodulator, a regulator, a power on reset, and a dynamically enabled digital phase locked loop (DPLL). The DPLL, with a charge pump enable circuit, was used to recover the clock of a 100% modulated ASK signal during the pause period. A high voltage lateral double diffused metal-oxide semiconductor transistor was used to protect the rectifier and the clock recovery circuit from high voltages. The proposed AFE was fabricated using the $0.18\;{\mu}m$ standard CMOS process, with an AFE core size of $350\;{\mu}m\;{\times}\;230\;{\mu}m$. The measurement results show that the DPLL, using a demodulator output signal, generates a constant 1.695 MHz clock during the pause period of the 100% ASK signal.