• Journal of the Korea Institute of Information and Communication Engineering
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• 제19권4호
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• pp.807-812
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• 2015

In RFID system, when multiple tags respond simultaneously, a collision can occur. A method that solves this collision is referred as anti-collision algorithm. In 13.56MHz RFID system of Auto-ID center, STAC protocol is defined as an anti-collision algorithm for multiple tag reading. The PS algorithm divides the tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. In this paper, we propose a STAC/PS algorithm that the PS algorithm is applied in the STAC protocol. Through simulations, it is demonstrated that the collision rate for the proposed algorithm is about 50% lower than STAC protocol. Therefore, the STAC/PS algorithm can achieve faster tag identification speed compared with STAC protocol due to the low collision rate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권5호
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• pp.776-796
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• 2010

Integrated RFID-WSNs (wireless sensor networks) have recently been researched to provide object identities, sensing information, mobile service, and network functionalities. In integrated RFID-WSNs, the reader collision is one of the critical problems. Above all, due to the absence of universally applicable anti-collision protocols and the channel capture phenomenon, the medium access control protocols in integrated RFID-WSNs suffer from reader collision and starvation problems. In this paper, we propose an efficient MAC protocol, called EMP, to avoid the above problems in integrated RFID-WSNs. EMP is a CSMA-based MAC protocol which is compatible with sensor networks operating on integrated nodes which consist of an RFID reader and a senor node. EMP resolves not only the reader collision problem, but also the starvation problem using a power control mechanism. To verify the performance of EMP, we compared it with other anti-reader collision MAC protocols using simulations. As a result, the performance of EMP showed improvements in throughput, system efficiency, and energy consumption compared to the single data channel protocols (CSMA/CA, Pulse, and DiCa) in dense deployment environments.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제31권5C호
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• pp.540-547
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• 2006

This paper proposes a novel anti-collision method for the ISO/IEC 18000-6 type B protocol which is the standard protocol of the 900 MHz RFID system. We improve the anti-collision performance by reducing the transmission number of commands and the length of bits required for multi-tag identification in the ISO/IEC 18000-6 type B protocol. Simulation results show that the proposed method improves the multi-tag identification time by 21.7% over the conventional method, irrespective of number of tags.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권3호
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• pp.413-420
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• 2006

In this thesis, a RFID baseband system is implemented based on the international standard ISO/IEC 18000-6 Type-B using FPCA, and also anti-collision algorithm is implemented to improve the system performance. We compares the performance of the proposed anti-collision algorithm with that binary tree algorithm and bit-by-bit algorithm, and also validated analytic results using OPNET simulation. The proposed algorithm for Type-B transmission protocol and collision prohibition was designed using ISE7.1i which is a FPGA design-tool of Xilinx and implemented with Spartan2 chip which is a FPGA device.

• Journal of the Korea Society of Computer and Information
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• 제17권2호
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• pp.207-214
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• 2012

This paper is to improve an identification ratio of tags by analyzing Slotted ALOHA, Dynamic Slotted ALOHA, Binary-tree and Query-tree and shortening the tag identification time in mobile RFID. Also, it enables the stable information transmission of tags by saving backscattering power of tags through shortening of identification time. As a result, this increases the available time of the battery and accessibility to a RFID service. For this, we proposed the energy-efficient tag anti-collision protocol for mobile RFID. The proposed scheme shows advanced result in identification time and collision counts. This scheme may be the first attempt for the mobile anti-collision.

• Korean Journal of Materials Research
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• 제29권9호
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• pp.525-531
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• 2019

The widespread use of automobiles has greatly increased energy demand and exhaust gas pollution. In order to save energy, reduce emissions and protect the environment, making lightweights automobiles is an effective measure. In this paper, carbon fiber composites and automobile B-pillars are briefly introduced, and then the mechanical properties and impact resistance of the DC590 steel B-pillars and carbon fiber composites B-pillars are simulated by the ABAQUS finite element software. The results show that the quality of compound B-pillars is reduced by 50.76 % under the same dimensions, and the mechanical property of unit mass is significantly better than that of metal B-pillars. In the course of a collision, the kinetic energy of the two B-pillars is converted into internal energy, but the total energy remains the same; the converted internal energy of the composite B-pillars is greater, the deformation is smaller and the maximum intrusion and intrusion speed is also smaller, indicating that the anti-collision performance of the composite B-pillars is excellent. In summary, the carbon fiber composites can not only reduce the quality of the B-pillars, but also improve their anti-collision performance.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제28권6B호
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• pp.544-552
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• 2003

This paper suggests an instruction code sufficiency algorithm preventing data collision when multiple transponders attempt to connect in the radio frequency identification system. Conventional time domain procedure generates unconditional collision. On the other hand, this algorithm prevents data collision by transmitting data when it meets instruction code. When multiple transponders are transmitting data coincidently, they exploit desired data with using difference of arrival time generated by recognition distance, respectively. As a result of simulation, utilizing the wireless recognition system, adopting the suggested algorithm, operating in 13.56MHz frequency band, it verify that there is Anti-collision and data loss by ensuring transmission time difference of one bit by adopting this algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제33권10A호
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• pp.987-996
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• 2008

In this paper, the conventional anti-collision algorithms, such as Channel Monitoring algorithm and Pulse Protocol algorithm are analyzed. To decrease tag identification time, and increase system throughput and efficiency, we propose a new reader anti-collision algorithm, Pulse Protocol-based Hybrid Reader Anti-collision Algorithm, using Slot-occupied Probability under dense reader environment. The proposed algorithm uses Slot-occupied Probability to improve the performance of Pulse Protocol Algorithm. That is, A reader checks Slot-occupied Probability after generating random backoff time. If Slot-occupied Probability is greater than 0, it uses another new random backoff time to avoid reader collision. We also compare the performance of the proposed algorithm with those of Channel Monitoring and Pulse Protocol algorithms in respect of identification time system throughput, and system efficiency. Simulation results show that the proposed algorithm has an increment of 5% of identification time and system throughput as increasing the number of readers.