• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.1929-1945
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• 2011

RFID technologies have attracted a lot of attention in recent years because of their cost/time-effectiveness in large-scale logistics, supply chain management (SCM) and other various potential applications. One of the most important issues of the RFID-based systems is how quickly tags can be identified. Tag collision arbitration plays a more critical role in determining the system performance especially for passive tag-based ones where tag collisions are dealt with rather than prevented. We present a novel tag collision arbitration protocol called Optimum Frame-Slotted Aloha (OFSA). The protocol has been designed to achieve time-optimal efficiency in tag identification through an analytic study of tag identification delay and tag number estimation. Results from our analysis and extensive simulations demonstrate that OFSA outperforms other collision arbitration protocols. Also, unlike most prior anti-collision protocols, it does not require any modification to the current standards and architectures facilitating the rollout of RFID systems.

• ETRI Journal
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• 제30권5호
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• pp.653-662
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• 2008

Arbitration of tag collision is a significant issue for fast tag identification in RFID systems. A good tag anti-collision algorithm can reduce collisions and increase the efficiency of tag identification. EPCglobal Generation-2 (Gen2) for passive RFID systems uses probabilistic slotted ALOHA with a Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. In this paper, we analyze the performance of the Q algorithm used in Gen2, and analyze the methods for estimating the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose new tag anti-collision algorithms, namely, Chebyshev's inequality, fixed adjustable framed Q, adaptive adjustable framed Q, and hybrid Q. The simulation results show that all the proposed algorithms outperform the conventional Q algorithm used in Gen2. Of all the proposed algorithms, AAFQ provides the best performance in terms of identification time and collision ratio and maximizes throughput and system efficiency. However, there is a tradeoff of complexity and performance between the CHI and AAFQ algorithms.

• 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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1460-1478
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• 2020

This paper proposes a novel anti-collision protocol for large-scale RFID tags identification, named Bi-response Collision Tree Protocol (BCT). In BCT, two group of tags answer the reader's same query in two response-cycles respectively and independently according to the bi-response pattern. BCT improves the RFID tag identification performance significantly by decreasing the query cycles and the bits transmitted by the reader and tags during the identification. Computation and simulation results indicate that BCT improves the RFID tag identification performance effectively, e.g. the tag identification speed is improved more than 13.0%, 16.9%, and 22.9% compared to that of Collision Tree Protocol (CT), M-ary Collision Tree Protocol (MCT), and Dual Prefix Probe Scheme (DPPS) respectively when tags IDs are distributed uniformly.

• Journal of Biomedical Engineering Research
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• 제28권3호
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• pp.325-331
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• 2007

Personal identification is essential for the automatic measurement of biosignal information in home healthcare systems. Personal identification is usually achieved with passive radio frequency identification (RFID), which does little more than store a unique identification number. However, passive RFID is not ideal for automatic identification. We present a user identification system based on radio signal strength indication (RSSI) using ZigBee for active RFID tags. Personal identification is achieved by finding the largest RSSI value from aggregated beacon messages that are periodically transmitted by active RFID tags carried by users. Obtaining reliable person!'.! identification without restricting the orientation requires a certain distance between the closest active RFID tag from the ZED and the second closest tag. The results show that the closest active RFID tag from the ZED and the second closest tag must be at least 70 cm apart to achieve reliable personal identification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.565-568
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• 2005

RFID system allows contactless identification of objects, where small tags are attached to objects and information of objects are transferred using radio frequency. In recent years, industries have incorporated several identification systems to its production processes, which allow collecting automatically information about goods. In order to communicate with a single tag out of a group of tags, the target tag has to be identified. Therefore the read has to attempt to obtain the unique identification code of each tag within its read range. This paper presents performance results of QT and QT-sl protocols, which are tag identification protocols incorporating memoryless property. The memoryless property is that the current response of each tag only depends on the current query of the reader but not on the past history of the reader's queries.

• The KIPS Transactions:PartC
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• 제11C권4호
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• pp.447-454
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• 2004

This paper proposes unforgeable RFID variable n scheme with efficient identification. The existing schemes on privacy protection are in efficient because a server should execute identification process with all Tag ID's Information in order to identify a certain Tag. Moreover these schemes have the serious problem that an attacker can forge special tags if he can know tag's secret information stored in the server's database. Our scheme Is required only 2 times exponent computation to identify a tag. The proposed scheme is also secure against leakage of tags information stored in a database, because an attacker cannot forge special tag even if he knows secret information of the server(database).

• Journal of the Korea Institute of Information and Communication Engineering
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• 제15권1호
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• pp.195-202
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• 2011

RFID(Radio Frequency IDentification) is a system to identify objects and its usage is being extended to distribution, healthcare, and air&port etc. RFID is a contactless system environment, and reducing tag authentication time is important because multiple tags are identified at the same time. Studies about RFID system so far is, however, mostly to improve security vulnerability in the tag authentication process. Therefore, this paper suggests an efficient scheme to decrease the time of tag authentication which is also safe for the security of tag authentication process. The proposed scheme cuts down on the tag ID search time because it searches only the classified relevant ID in the database, which is one of many components of RFID system, by using identification bits for tag ID search. Consequently, the suggested scheme decreases process time for tag ID authentication by reducing the processing time and the load of the database. It also brings performance improvement of RFID system as it improves the energy applicability of passive tag.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제33권8A호
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• pp.805-814
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• 2008

Both EPCglobal Generation-2 (Gen2) for passive RFID systems and Intelleflex for semi-passive RFID systems use probabilistic slotted ALOHA with Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. A better tag anti-collision algorithm can reduce collisions so as to increase the efficiency of tag identification. In this paper, we introduce and analyze the estimation methods of the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose two new tag anti-collision algorithms, which are Chebyshev's inequality (CHI) algorithm and hybrid Q algorithm, and compare them with the conventional Q algorithm and adaptive adjustable framed Q (AAFQ) algorithm, which is mentioned in Part I. The simulation results show that AAFQ performs the best in Gen2 scenario. However, in Intelleflex scenario the proposed hybrid Q algorithm is the best. That is, hybrid Q provides the minimum identification time, shows the more consistent collision ratio, and maximizes throughput and system efficiency in Intelleflex scenario.

• Journal of Korea Society of Industrial Information Systems
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• 제15권3호
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• pp.1-9
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• 2010

In recent year, the cores of ubiquitous environment are sensor networks and RFID systems. RFID system transmits the electronic information of the tag to the reader by using RF signal. Collision happens in RFID system when there are many matched tags, and it degrades the tag identification performance. Such a system needs algorithm which is able to arbitrate tag collision. This paper suggests a hybrid method which reduces collision between the tags, and can quickly identify the tag. The proposed method operates based on certainty, which takes an advantage of tree based algorithm, and to reduce collision it selects transmission time slot by using tag ID. The simulation results show the suggested method has higher performance in the number of queries and collision compared to other tree based and hybrid algorithms.