• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.4
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• pp.309-312
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• 2005

The RFID tag IC has been presently abstracting great attention in the world because it can be one of the important sensor elements in the ubiquitous sense network in the future. The 125 kHz and 13.56 MHz RFID tag IC's have already been developed and now widely used in the world and the UHF band tag IC is under development. Domestically, the development of the 125 kHz tag IC was reported before, but there has been no report about the development of the 13.56 MHz tag IC up to now. In this paper, the results of the design, fabrication and measurement of a 13.56 MHz tag IC are discussed. The digital and the analog circuits for the chip were designed and the chip was fabricated using 0.35 ㎛ standard CMOS technology and measured with a separately prepared reader. It was found from the measurement results that it operated properly within 8 cm range of the reader.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.3
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.626-633
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• 2009

ISO/IEC/WD 24753 defines new modem specifications for a long-range RFID communications and application protocol for a sensor tag system. According to the standard, the frequency offset of the tag is 4%. In general wireless communications systems, it is known that a coherent receiver is superior to a non-coherent receiver. However, if the frequency offset is large, it is difficult to restore the original data accurately with a coherent receiver, and the performance of a coherent receiver is easily degraded. In this paper, a non-coherent receiver structure is adopted to solve the frequency offset problem of long-range RFID communications. We designed a frequency estimation block to find an optimal frequency from the received signal with 4% frequency offset and proposed a start frame delimiter (SFD) detection algorithm to determine the start position of the payload. The frequency estimation block finds the optimal frequency from the received signal using 9-correlators. And the SFD detection block searches the received signal to find the start position of the payload with dual correlator. We implemented a long-range RFID reader with the proposed methods and evaluated its performance in a wired/wireless test network. The implemented long-range RFID reader showed more superior performance than the commercial RFID reader in terms of recognition range.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.8
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• pp.842-852
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• 2010

RFID applications use tags to identify objects, but recent applications tend to include diverse sensor devices such as light, temperature, and humidity sensors as well. RFID tag information is usually processed via the event driven model. However sensor devices are usually accessed via the functional call model. Therefore application developers have to deal with mixed data access models and device dependent interface functions. In this paper, we propose a sensor reader emulator that provides a consistent access interface to sensor devices regardless of the types of devices. SRE provides a more efficient way of developing RFID applications by providing a single application programmer's view to RFID tags and sensor devices. In applications where tags are fixed to a place, SRE can replace expensive sensor tags and sensor readers with inexpensive sensor devices reducing the total cost while providing the same functionality.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.55
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• pp.16-24
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• 2005

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1686-1697
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• 2011

This paper aims to build up a RFID-automated cargo movement system in an air-cargo warehouse. In our research, we do the spectrum measurements compliant with the RFID frequency bands to observe the interferences from legacy systems in the air-cargo warehouse. To overcome the dense-reader mode (DRM) problem, we apply three novel approaches, which are the periodic transmit of a reader, the Visible RFID reader & tag, and the sensor-based RFID system. Moreover, for the tag collision issue, we implement the Adaptive Adjustable Framed Q(AAFQ) algorithm, and the demonstration on RFID tag anti-collision algorithms show that the AAFQ algorithm has highly desirable tag anti-collision performance compared to any other commercially available solutions.

• Journal of the Korea Society of Computer and Information
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• v.23 no.5
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• pp.25-29
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• 2018

As society advances and consumers' perception of food safety changes, the demand for the safety of refrigerated and distributed foods is spreading. In this paper, we build an ICT system that can collect the TTH data from the NFC tag, store it, analyze the food safety level using it. This service platform consists of the temperature monitoring NFC tag attached to individual packaged food, the smartphone with NFC sensor, and the monitoring server with a big data system. Consumers and administrators in this system can easily identify and predict the safety level of individual packaged foods in real time using the provided app on smartphones. In the field of food safety, the use of new technologies such as ICT can create new value by combining with existing food industry in addition to creating new market by new service.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.537-542
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• 2014

Track circuit is a simple electrical device which lies in the connection of the two rails by the wheels and axle of locomotives and rolling stock to short out an electrical circuit, used to detect the absence of a train on rail tracks. In railway signaling system, there are similar systems such as RFID and wheel sensor, GPS etc, are research and developing. Hybrid track circuit is using RFID antenna and reader on the cab and RFID tag on the sleeper. because of the safety in railway operation, tag detection of train position detection function in the hybrid track circuit needs high reliability. This paper studied tag recognition enhancement used tag angles.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.237-240
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• 2007

최근 '정보기반 물류망'에서 'u-기반 물류망'으로 발전해 가고 있는 시점에서 'u-기반 물류망'을 위해 다양한 기반 기술들이 요구되고 있다. 본 논문에서는 물류 관리 시스템 구축을 위해 GPS 기반의 물류위치 추적 기법과 센서 Tag를 이용한 물류 배송 효율화 시스템을 설계하고 구현한다. 또한, 물류 배송 효율화를 위해 센서 Tag 네트워크 시스템을 제안하며, 이 센서 Tag 네트워크를 기반으로 수집된 센싱 정보를 이용하여 물류의 위치와 상태, 이동경로 등을 파악함으로서 물류의 배송이 효율적으로 이루어 질 수 있도록 지원한다. 제안된 시스템은 관리자에 의해 유지 보수 될 수 있는 제어 가능한 센서 Tag 네트워크(Controlled Network Layer)와 무제어 이동 센서 Tag 네트워크(Uncontrolled Moving Objects Layer)로 구분하여, 일반적인 센서 네트워크 시스템의 배터리 문제를 보완하고자 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.183-188
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• 2017

This paper is for the a study on home healthcare system for a patient using SAW Tag. This system is useful when there's a patient in home. Many patients are wounded in restroom. But restroom is very private place and nobody want to be disturbed here. The place where the patient is most injured in the house is the toilet, and it is the point where the privacy of the individual should be kept and the patient's condition should be checked and cope with in case of emergency. And using saw tag, we can calculate position and ID through reflected rf signal. Therefore we propose a general home healthcare system. The management system utilized a seat bed system to monitor at-home patients. The system mounts a bio-signal measuring unit on a toilet seat, measures a bio-signal from the bio-signal measuring unit, and the measured bio-signal is transmitted to the main server through the user's smart phone. With proposed system, we can expand operation area to silver town where many patients are cared. In this paper we developed sensor system and saw tag positioning system and showed the result.