• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.249-258
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• 2006

In this letter, we propose a novel printed helix antenna for RFID reader in UHF band. The printed strip line of the antenna is first wound up outside a polygonal shaped layer and then the winding continues on an inner layer to control the overall gain and the radiation pattern. In addition, the winding pitch angles on each layer have either negative or positive values resulting in the broad CP bandwidth. The detail structure of the antenna was optimized using Pareto genetic algorithm(GA), so as to obtain excellent performances for RFID reader antennas. The optimized two-layered polygonal helix was fabricated on the cardboard of a flexible substrate and the performances were measured and compared with the simulations. The fabricated antenna was made up of copper tape which can adhere to a flexible cardboard and had 21.4 % matching bandwidth, 31.9 % CP bandwidth, readable range of $5.5m^2$ with kr=3.2. Also based on the current distribution of the strip line of the antenna and sensitivity of the antenna bents points, we confirmed that the antenna has the quarter-wave transformer near the feed for the broad matching bandwidth and radiates the traveling wave for the broad CP bandwidth using the bent strip line.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.62-72
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• 2009

In this paper, we propose an application of RFID(Radio Frequency Identification) tag to food wastes disposal system of Cheongju city. The existing system of Cheongju city is monthly fixed amount levy system. The weak point of this system must pay a same commission in spite of each other different food wastes quantity. Also the accurate occurrence quantity of the food wastes and present condition grasp of control are impossible. It will not be able to reflect to a policy decision because does not manage the control of the food waste efficiently. On the other hand, when a food wastes measuring system using RFID is executed tag, it will manage and analyze automatically the obtained data. And collecting, transporting and handling of the food wastes come to be very easy. Also the reproduction and embezzlement of the tag are impossible. As a result of this system, it brings the decrement of the food waste. Therefore the economic effect could be come true and the food wastes is controlled environment-friendly. The food wastes disposal system using RFID tag will be able to contribute in u-city constructions with RFID/USN technology which pursues from the government.

• Food Science and Preservation
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• v.17 no.1
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• pp.79-83
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• 2010

The study was conducted to analyze the tag reading and box recognition performance of a gate-type RFID system using the UHF band to detect containers of red pepper. The reading rate of tags attached to container boxes was higher as tags were closer to antennas and the number of antennas was increased. Under optimal conditions, the reading rate was 100% and the range of distance from a carton to an antenna was 1-4 meters. When tags were attached to two sides of a box, the reading rate was lower when the tags were attached at the front and side. This was caused by data collision problems between tags. The reading rate of tags was 71.1-77.8% and the reading rate of red pepper boxes was 97.8-100.0% when the distance between the pallet under the boxes and four units of antennas was 5 meters or less, and when tags were attached at the front and side of boxes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.143-146
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• 2009

The restaurants have been forced to inform the origin of ingredients to consumers due to the origin obligation policy enacted in 2008 October. However, it is difficult to trust the policy because the origin is represented by a manager's conscience. Therefore, in order to provide consumers with reliable information, we have designed, and embodied the agricultural management system using RFID and USN technology. By installing system on agricultural plantations this system not only manages environmental data such as temperature, illumination and humidity collected in real time but also offers consumers the information of fertilizers or pesticides sprayed on the crops. Before purchasing, consumers will be able to check raw flesh process and the fertilizer and agricultural chemical scattering scene of the crops as an image by using RFID tags with a leader, which more increase the reliability.

• Korean Journal of Construction Engineering and Management
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• v.12 no.4
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• pp.106-116
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• 2011

It is very important to collect and manage labor information in the construction industry that is labor-intensive. Although research and cases that utilize RFID are increasing for more effective labor management, labor management is limited to the checking-in and -out information management at the entrance of a construction site due to high expense of an RFID reader. Labor and safety information is still managed based on the redundant process that is hand-written in a book and re-input of information by using a personnel-computer. Therefore, the objective of this paper is to develop more effective and efficient process for labor information record and management. This paper presents a prototype application that supports integrated labor information management by incorporating QR-code into RFID-based labor management system and verifies the application through a pilot test and comparison with the existing labor management syste.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.405-415
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• 2012

In many applications a reader needs to determine whether a particular tag exists within a group of tags without a server. This is referred to as serverless RFID tag searching. A few protocols for the serverless RFID searching are proposed but they are the single tag search protocol which can search a tag at one time. In this paper, we propose a multi-tag search protocol based on a hash function and a random number generator which can search some tags at one time. For this study, we introduce a protocol which can resolve the problem of synchronization of seeds when communication error occurs in the S3PR protocol[1], and propose a multi-tag search protocol which can reduce the communication overhead. The proposed protocol is secure against tracking attack, impersonation attack, replay attack and denial-of-service attack. This study will be the basis of research for multi-tag serach protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1318-1327
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• 2012

With the recent increased risk of livestock disease spread and human infection, livestock disease control has become very important. Consequently, there has been an increased attention on an implantable real-time monitoring and traceability system for individual cattle. Therefore, we have developed a robust monitoring and traceability system based on an implantable MFAN/RFID sensor tag. Our design combines the MFAN technology that is capable of robust wireless communication within cattle sheds and the 900MHz RFID technology that is capable of wireless communication without battery. In MFAN/RFID implantable sensor tag monitoring system, UHF sensor tag is implanted under the skin and accurately monitors the body temperature and biological changes without being affected by external environment. In order to acquire power needed by the tag, we install a MFAN/RFID tranceiver on the neck of cattle. The MFAN coordinator passes through the MFAN node and the RFID-reader-combined MFAN/RFID transceiver and transmits/receives the data and power for the sensor tag. The data stored in the MFAN coordinator is transmitted via the internet to the livestock history monitoring system, where it is stored and managed. By developing this system, we hope to alleviate the problems related to livestock disease control.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.359-359
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• 2006

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.247-252
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• 2013

In this paper, a microwave tag system of a frequency-scanning type is proposed with multi-resonators using defected ground structures. While a conventional chip-based RFID stores time-sequential codes, the proposed type achieves pure passive tags by using multi-resonant bits over a frequency range. Moreover, the resonators of the spiral defected ground structures implemented on the back side of transmission lines have advantages of the excellent bandstop characteristics as well as the bit-error avoidance by the re-radiation on normal resonators. The proposed microwave tag is designed with UWB antennas at 3~7 GHz. From the experimental results in an anechoic chamber, it has been verified of the excellent recognitions for various 5-bits identification codes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.81-91
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• 2009

Recently, Chein et al proposed the ultralightweight strong authentication and strong integrity (SASI)protocol, where the tag requrires only simple bitwise operations. Since the tag does not support random number generator to generate a challenge nonce, an attacker can replay old messages and impersonate reader. However, all of the previous ultralightweight authentication schemes are vlunerable to various attacks: de-synk, eavesdropping, impersonating, tracking, DoS, disclosure etc. we analyze the problems of previous proposed ultrlightweight protocols, to overcome these security problems by using PRNG on the tag. Therefore, in this paper we propose a new lightweight RFID mutual authentication protocol that provides random number generator and bitwise operations, a security and an efficiency of the proposed schme analyze.