• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.561-566
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• 2011

In EPCglobal Class-1 Gen-2 RFID system, a slot-count selection algorithm has been proposed to determine the slot-count size depending on the status of reply slot. In the slot-count selection algorithm of Gen-2, the slot-count value is increased or decreased by the weight C, which is identical and independent of the slot status. It has an advantage that the algorithm is simple, but it is difficult to maintain an optimal slot-count size. Therefore, in this paper, we propose an adaptive slot-count selection algorithm, which applies the parameter C differently based on the result of tag replies. Through simulations, it is demonstrated that the collision rate for the proposed scheme is about 42% and 65% lower than the schemes proposed by Wang and Gen-2. Therefore, the adaptive slot-count selection algorithm achieves faster tag identification time compared with the existing algorithms due to the low collision rate.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.9
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• pp.29-37
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• 2004

In RFID system one of the problems that we must solve is to devise a good anti-collision algorithm to improve the efficiency of tag identification which is usually low because of tag collision. Among the existing RFID anti-collision algorithms, Framed Slotted ALOHA algorithm though simple, has a disadvantage that the number of slots used to identify the tags increases exponentially as the number of tags does. In the paper, we propose a new anti-collision algorithm called Partial-Response Framed Slotted ALOHA(PRFSA) which restricts the number of responding tags by dividing the tags into a number of groups when there are large number of tags and changes the frame size when there are small tags. Since the proposed algorithm keeps the frame size and the number of responding tags in such a way that can increase slot utilization, the algorithm shows superior performance to the existing ones. The simulation results showed that the proposed algorithm improves the slot efficiency by 85～100% compared to the existing algorithm.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.223-228
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• 2023

Sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. In this study, the amount of voltage and current generated was measured by applying the PSD profile random vibration test of the electronic vibration tester and ISTA 3A according to the time of Anodized Aluminum Oxide (AAO) pore widening of the manufactured TENG device Teflon and AAO. The discharge and charging tests of the integrated module during the random simulated transport environment and the recognition distance of RFID were measured while agricultural products (onion) were loaded into the returnable folding plastic box. As a result, it was found that AAO alumina etching processing time to maximize TENG performance was optimal at 31 min in terms of voltage and current generation, and the integrated module applied with the TENG module showed a charging effect even during the continuous use of RFID, so the voltage was kept constant without discharge. In addition, the RFID recognition distance of the integrated module was measured as a maximum of 1.4 m. Therefore, it was found that the surface condition of AAO, a TENG element, has a great influence on the power generation of the integrated module, and due to the characteristics of TENG, the power generation increases as the surface dries, so it is judged that the power generation can be increased if the surface drying treatment (ozone treatment, etc.) of AAO is applied in the future.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.127-130
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• 2005

In this paper, we investigated the change of recognition distance according to the resonance frequency of the transponder for the ISO 14443 Type A 13.56MHz RFID(Radio Frequency IDentification) system. We made thirteen transponders of the same size. The dimension of the transponder is $84.65mm{\times}53.00mm{\times}0.45mm$. We measured the resonance frequency by means of an inductive coupling. The measured resonance frequencies were between 12.9MHz and 17.3MHz. We measured the maximum distances where the transponder's USN(Unique Serial Number) was recognized and the subcarrier was observed. The measurement results show that we can obtain good performance when the Type A transponder has the resonance frequency around 14.2MHz for the given case.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.273-278
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• 2005

The characteristics of the tag antenna are influenced much with the change of the electrical properties of its substrate material, conducting metal-line and the surrounding environments. In this paper, we study the characteristics of tag antenna according to the electrical variations of those substrate materials, metal-line and the surrounding environmental conditions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.3
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• pp.258-272
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• 2010

The low-rate (LR) UWB is a promising technology for the ubiquitous sensor network (USN) due to its extremely low power consumption and simple transceiver implementation. However the limited communication range is a bottleneck for its widespread use. This paper deals with a new frame structure of class 4 active RFID multi-hop relay system based on ISO/IEC 18000-7 standard integrating with IEEE 802.15.4a LR-UWB PHY layer specification, which sets up a connection to USN. As a result of the vital importance of the coverage and throughput in the application of USN, further we analyze the performance of the proposed system considered both impulse radio UWB (IR-UWB) and chirp spread spectrum (CSS). Our simulation results show that the coverage and throughput are remarkably increased.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.364-369
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• 2008

The FSA algorithm for identifying multiple tags in RFID systems is based on the slotted ALOHA scheme with a fixed frame size. The performance of FSA algorithm is dependent on the frame size and the number of tags in the reader's identification range. Therefore, this paper proposes a new ODFSA. The proposed ODFSA algorithm dynamically allocates the optimal frame size at every frame based on the number of tags in the reader's identification range. According to the simulation results, the system efficiency of the proposed algorithm should be maintained optimally. Also, the proposed algorithm always obtained the minimum tag identification delay.

• Proceedings of the KIEE Conference
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• 2008.05a
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• pp.157-158
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• 2008

In this paper, a dual band microstrip patch Antenna is designed for RFID Application. The antenna shows a good performance at the frequencys, 433MHz and 2.45GHz for the radiation characteristics and input impedance matching as well. The reflection factor is lower than 15dB and a good directivity higher than 3dB is achieved for both frequency.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.185-188
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• 2007

현재 Ubiquitous기술의 핵심인 RFID 기술은 다양한 분야에서 이를 활용하기 위한 연구들이 활발히 진행 되고 있다. 그러나 RFID 시스템은 구조상 무선으로 동작 되는 불안정한 구간이 있으며 이 구간 사이의 EPC 데이터를 수집, Filtering, 분석 등으로 수많은 EPC데이터가 저장되며 이를 필요로 하는 곳에 제공하게 된다. 본 논문은 EPCglobal의 표준을 따른 EPCIS를 위한 RFID 성능 향상 방안을 제안 한다. 제안을 바탕으로 구현 할 때 Tag의 EPC 데이터 신뢰성은 향상되며 데이터베이스의 저장 공간의 불필요 사용을 줄일 수 있으며 개선된 EPCIS를 구현할 수 있는 시스템 이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.875-876
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• 2007

본 논문에서는 지능적으로 폴링과 랜덤접속모드를 사용하는 RFID 충돌방지 기법을 제안하고자 한다. 본 논문에서 제안하고자 하는 충돌방지 알고리즘은 태그의 교체율이 크지 않을 경우, 먼저 이전 인식과정에서 성공적으로 식별한 태그들에 대한 고유정보를 기억한 뒤 다음 인식 세션에서 그 고유 정보를 활용하여 출석을 부르는 것처럼 경쟁 없이 태그들을 호출하여 빠르게 식별한다. 이전 세션(session)에 비하여 많은 수의 태그가 교체되었으면 인식률이 저하될 수 있다. 이 경우에는 랜덤 접속모드로 전환하여 나머지 태그들을 읽어 낸다. 본 논문에서 제안하는 것처럼 인식이력을 활용한 모드와 랜덤 접속 모드를 적절히 조합하여 운용하면 태그 인식 시간을 단축할 수 있으며, 특히, 주기적으로 개체의 존재 유무를 확인하는 응용의 경우에 우수한 성능 향상을 얻을 수 있다.