• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.789-792
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• 2007

본 논문에서는 단일리더기가 아닌 멀티리더기를 이용하여 리더기들간의 상호 협동작업을 통하여 일정한 속도로 이동하는 태그를 최대한 많이 읽을 수 있는 멀티리더기들간의 협업을 이용한 향상된 태그인식 알고리즘을 제안하였다. 즉, 두 개의 리더기를 사용하여 많은 양의 태그가 서로 다른 이동 속도로 리더기를 지나 갈 때, 첫 번째 리더기가 저장해 놓은 태그정보를 두 번째 리더기가 이어받아 계속하여 나머지 태그를 인식하는 알고리즘을 개발한다. 시뮬레이션 결과 멀티리더기를 이용하면 단일리더기의 단점을 극복하여 보다 향상된 태그 인식 결과를 얻어내어 좀 더 안정적이고 효율적인 알고리즘을 제안하였다.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.37-44
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• 2009

In this paper, we present a switched beamforming RFID reader and propose a convenient shopping system using it. The smart gate with the switched beamforming RFID reader(s) improves tag detection probability, tag false alarm probability, automatic detection functionality of shopping system compared to existing RFID based systems. The proposed system consists of a smart gate to read and verify the tags within cart, a check-out counter to approve customer purchase, and a central server to manage inventory & delivery and to analyze customer purchase trend. The proposed shopping system is more practical, convenient, and cost-effective to A/S than existing RFID shopping systems.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.40-50
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• 2009

Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.715-719
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• 2009

Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.9
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• pp.598-605
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• 2014

In this paper, we suggest a modified slotted ALOHA algorithm for fast tag collection in active RFID system and implement the reader and tag operation using CC2530 chip of Texas Instruments Co. to prove the performance of the proposed algorithm. In the present international standard related with active RFID including ISO/IEC 18000-7 the reader sends sleep command to each tag after successful obtaining tag's information. Meanwhile, in this paper, the tags decide to sleep after checking the second command from the reader resulting in enormously decreased tag collection time. We tested the proposed algorithm with 30 tags over the range of 0-3m and the results showed that the tag collection process was completed in 400msec at average. And 30 tags are collected in one second with 99.7% and the collection rate is 100% in 2m distance between reader and tag. The collection rates are 99.94% and 99.7% for distance 2.5m and 3m, respectively. The average collection rate is 99.91% over all range and it is concluded that the proposed algorithm is enough to apply to real fields.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.616-619
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• 2012

When multiple Tags transmit their IDs to the Reader, tag identification time is delayed due to collisions. Therefore, to reduce the reader's identification time, an efficient anti-collision technology is needed. In this paper, a new anti-collision method is proposed. The method estimates the number of tags and allocates proper number of slots based on the DFSA. The performance of proposed method is compared with existing methods through extensive simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1619-1624
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• 2012

If multiple Tags in the RFID System transmit their IDs to the Reader at the same time, tag identification time is delayed due to collisions. Therefore, to reduce the reader's identification time, an efficient anti-collision technology is needed. In this paper, we propose a hybrid anti-collision method based on the QT and DFSA. Then, the performances of proposed method are compared with the existing method through extensive simulations.

• Journal of the Society of Disaster Information
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• v.15 no.3
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• pp.391-401
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• 2019

Purpose: In this study, the location and history information of the cavity identified in the cavity exploration, such as repacking of the pavement, is not known. Therefore, it is to review the field applicability of RFID(Radio Frequency Identification) systems that enable anyone to accurately identify information. Method: Basic experiments were conducted for field applicability for cavity recognition distance, recognition and recognition rate, tag performance and tag type, reader interference, communication, underground burial impact, and duplicate recognition by RFID system. Results: As a result of the depth of tag and reader recognition, the electronic tag chips and readers applied in the basic experiment are judged to be effectively applicable in the field environment where the road cavity is located. Conclusion: The RFID tags for field application of the pavement management system store various information such as location and size of cavity, identification date, cause of occurrence, and surrounding underground facilities to maximize cavity management effect with a system that can be computerized and mobile utilization.

• 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.

• 프린팅코리아
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• v.7 no.8
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• pp.38-43
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• 2008

RFID(Radio Frequency Identification)는 IC칩과 무선을 통해 식품, 동물, 사물 등 다양한 개체의 정보를 관리할 수 있는 첨단 인식 기술이다. 기존에 널리 사용되고 있는 바코드가 일정한 방향으로 인쇄된 내용을 리더기를 이용해야만 인식하는데 비하면 RFID는 초소형칩(IC)을 내장해 무선 주파수로 추적하기 때문에 인식범위가 넓고 인식 속도 역시 매우 빠르다. 뿐만 아니라 담을 수 있는 정보량에서도 모델에 따른 차이는 있지만 바코드와는 비교가 되지 않을 정도로 많다.