• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.317-318
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• 2008

효율적인 유통 물류매장 서비스를 지원하기 위해서는 RFID 미들웨어의 상태나 성능이 유동적인 환경에 대비하여 리소스의 안정적인 분배를 지원하는 환경이 필요 하다. 본 논문에서는 실제 산업 현장의 현실을 감안하여 소프트웨어 최소 요구사양으로 미들웨어 구성을 제시하는데, 필요한 정보를 제공하는데 그 목적을 두었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.287-288
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• 2008

본 논문에서는 900MHz 대역의 RFID 시스템을 생산하는 대표적인 두 제조사의 제품을 선정하여 다양한 관점에서 성능을 측정하였다. 인식률 시험과 인식범위 시험으로 구분하여 8개 항목에 걸쳐 실험을 수행한 결과 A, B사 모두 태그부착 재질이 철재 및 알루미늄일 때, 태그가 겹쳐졌을 때, 태그 CHIP이 손상되었을 때 태그 인식이 되지 않았다. 그리고 시험환경 및 조건에 따라 다양한 인식률 변화에 대한 데이터를 도출 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.337-339
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• 2007

This paper proposes a new paradigm for cooperation of multi-robot system for home service. For localization of each robot. the master robot collects information of location of each robot based on communication of RFID tag on the floor and RFID reader attached on the bottom of the robot. The Master robot communicates with slave robots via wireless LAN to check the motion of robots and command to them based on the information from slave robots. The operator may send command to slave robots based on the HRI(Human-Robot Interaction) screened on masted robot using information from slave robots. The cooperation of multiple robots will enhance the performance comparing with single robot.

• 한국항해항만학회지
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• 제30권4호
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• pp.285-290
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• 2006

Shipping companies consider most of the ship turnaround time as a critical factor when selecting a rolling port for reducing costs. So, many researchers have been studying for the optimization of preplanning and high~performance of the Gantry Cranes (GCs) in container terminals for faster loading and unloading. Therefore, in this paper, we propose an RFID (Radio Frequency Identification) based RTLS (Real-Time Location System) for reducing the ship turnaround time in ubiquitous port environment. In addition, pre-planning based on ubiquitous computing environment will support the GC and Yard Tractors (YTs), and reduce ship turnaround time more effectively. Especially, the proposed method enormously enhances the productivity of loading for the twin-lift system It will reduce the whole lead-time in the process of port logistics.

• 한국ITS학회 논문지
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• 제7권6호
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• pp.70-80
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• 2008

본 논문에서는 18000-3 RFID 표준인 ASK 모드와 PJM 모드 RFID 시스템을 인식속도의 관점에서 비교하였다. ASK 모드와 PJM 모드 리더/태그간 통신 과정을 표현 할 수 있는 대표 블록들의 조합을 구성하여 블록이 발생한 횟수를 이용하여 인식속도를 비교하였다. FS-Aloha 기반 프로토콜을 적용시키기 위한 Q알고리즘으로 표준 기고서에서 예시로 제안한 알고리즘, Q값 고정 알고리즘, 최소 Q 알고리즘 그리고 남은 태그 수에 연동한 Q값 설정 알고리즘을 이용하였다. 시뮬레이션 과정을 통해서 Q알고리즘에 따른 ASK 모드와 PJM 모드 속도 비교뿐만 아니라 Q알고리즘을 고정시킨 후 ASK 모드와 PJM 모드의 인식속도를 비교하였고 속도에 영향을 미치는 파라메타들을 도출하였다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.3-6
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• 2007

In this paper, a hybrid dual band LNA(Low Noise Amplifier) with a tunable matching circuit using varactor is designed for 433MHz and 912MHz RFID reader. The operating frequency is controlled by the bias voltage applied to the varactor. The measured results demonstrate that S21 parameter is 16.01dB and 10.72dB at 433MHz and 912MHz, respectively with a power consumption of 19.36mW. The S11 are -11.88dB and -3.31dB, the S22 are -11.18dB and -15.02dB at the same frequencies. The measured NF (Noise Figure) is 15.96dB and 7.21dB at 433MHz and 912MHz, respectively. The NF had poorer performance than the simulation results. The reason for this discrepancy was thought that the input matching is not performed exactly and a varactor in the input matching circuit degrades the NF characteristics.

• 대한산업공학회지
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• 제41권2호
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• pp.173-184
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• 2015

The application of radio frequency identification (RFID) sensor-tags in cold chain systems has recently received a great deal of attention. To design cold chain systems with RFID sensor-tags that minimize the initial investment and operational cost while fulfilling the functional and operational requirements, simulation study is one of the preferable and effective approaches. To simulate the possible design configurations, the individual components in a cold chain system can be extracted and implemented as a DEVS (Discrete Event System Specification) model. Based on the proposed DEVS model, a new cold chain simulation model can be efficiently created by simply connecting each DEVS model around the RFID sensor-tag of interest in sequence according to the structure of the cold chain system, and then executed (or simulated) on Java programming environments by the DEVSJAVA simulator. As a result of simulation, some key performance indexes such as reliability, accuracy or timeliness can be calculated and used to choose better components or to compare different system configurations of cold chain systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권7호
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• pp.1624-1637
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• 2013

In RFID systems, one important issue is how to effectively address tag collision, which occurs when multiple tags reply simultaneously to a reader, so that all the tags are correctly identified. However, most existing anti-collision protocols assume isotropic collisions where a reader cannot detect any of the tags from the collided signals. In practice, this assumption turns out to be too pessimistic since the capture effect may take place, in which the reader considers the strongest signal as a successful transmission and the others as interference. In this case, the reader disregards the other collided tags, and in turn, fails to read the tag(s) with weaker signal(s). In this paper, we propose a capture effect-aware anti-collision protocol, called Multi-Round Collision Tree (MRCT) protocol, which efficiently identifies the tags in real RFID environments. MRCT deals with the capture effect as well as channel error by employing a multi-round based identification algorithm. We also analyze the performance of MRCT in terms of the number of slots required for identifying all tags. The simulation results show that MRCT significantly outperforms the existing protocol especially in a practical environment where the capture effect occurs.

• 제어로봇시스템학회논문지
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• 제14권1호
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• pp.81-87
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• 2008

C-Hook is a kind of conveyer system for transporting steel coil in POSCO. To detect the current position and the trajectory of steel coils in a plant, C-Hooks are tracked by an inspection system based on PLC. The inspection system detects transit of C-Hooks by monitoring a physical contact between steel bars on a C-Hook and the inspection sensors. However, this system is not reliable because of the abrasion, damage and aging. Moreover, the number of distinguishable C-Hooks is limited by the number of combination of steel bars on a C-Hook. It means that more steel bars should be installed for distinguishing the more C-Hooks. Therefore, the conventional system is difficult and expensive to maintain. To overcome these problems, we propose a C-Hook identification system that uses RFID which is a non-contact type identification system, and evaluate its performance and applicability from a new monitoring program that operates along with the conventional system in the real environment of POSCO.

• 한국산업정보학회논문지
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• 제8권1호
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• pp.55-61
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• 2003

표준 암호화 알고리즘(DES : Data Encryption Standard)은 20년 이상 국제 암호화 표준으로 사용되고 있다. DES는 64비트의 데이터 블록을 56비트의 키를 이용하여 암호화시키는 블록 암호화 기법중의 하나이다. 이 알고리즘은 64비트의 입력을 연속된 과정에 의해 64 비트의 출력으로 전환하는 방법이며, 이렇게 암호화시킨 문장은 키 없이는 해독이 불가능하다. 본 논문에서는 DES 알고리즘을 이용하여 RFID(Radio Frequency Identification) 판독 시스템을 구현하였다. 구현된 시스템은 CBC(Cipher Block Chining) 모드를 사용하여 암호화 알고리즘의 신뢰성을 높였으며, 기존 상용 제품과의 성능 비교 결과 카드 접근 시간과 동작 시간이 상용 제품보다 우수함을 알 수 있었다.