• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.220-226
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• 2014

This paper proposes an enhanced fast scanning method for multi-agent robot system. Passive RFID tag can read and store the information within the range of recognizable RF tag reader. Based on this information of Passive RFID tag, the position of mobile robot can be estimated and at the same time, the efficiency of scanning process can be improved because it provides a scanning trace for other mobile robots. This paper proposes an dfficient motion planning algorithm for mobile robots in a smart floor environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12A
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• pp.1311-1319
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• 2007

This paper presents the VHDL implementation procedure of the passive RFID tag operating in Ultra High Frequency. The operation of the tag compatible with the EPCglobal Class1 Generation2(GEN2) protocol is verified by timing simulation after synthesis and implementation. Due to the reading range with relatively large distance, a passive tag needs digital processor which facilitates faster decoding, encoding and state transition for enhancement of an interrogation rate. In order to satisfy linking time, the pipe-line structure is used, which can minimize latency to serial input data stream. We also propose the sampling strategy to decode the Preamble, the Frame-sync and PIE symbols in reader commands. The simulation results with the fastest data rate and multi tags environment scenario show that the VHDL implemented tag performs faster operation than GEN2 proposed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.79-85
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• 2004

In this paper, the RF-ID system for ubiquitous tagging applications has been designed, fabricated and analysed. The RF-ID System consists of passive RF-ID Tag and Reader. The passive RF-ID tag consists of rectifier using zero-bias schottky diode which converts RF power into DC power, ID chip, ASK modulator using bipolar transistor and slot loop antenna. We suggest an ASK undulation method using a bipolar transistor to compensate the disadvantage of the conventional PIN diode, which needs large current Also, the slot loop antenna with wider bandwidth than that of the conventional patch antenna is suggested The RF-ID reader consist of patch array antenna, Tx/Rx part and ASK demodulator. We have designed the RF-ID System using EM and circuit simulation tools. According to the measured results, The power level of modulation signal at 1 m from passive RF-ID Tag is -46.76 dBm and frequency of it is 57.2 KHz. The transmitting power of RF-ID reader was 500 mW

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.117-134
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• 2010

A passive RFID tag which received attention as a future technology for automatic and quick identification faces some difficulties about security problems such as tag authentication, reader authentication, data protection, and untraceability in addition to cost and reliable identification. A representative passive RFID technology is the ISO/IEC 18000-6 Type C which is an international standard for 900 MHz UHF-band. This standard has some difficulties in applying to the security services such as originality verification, tag's internal information protection, and untraceability, because it does not provide high-level security solution. In this paper, we summarize security requirements of ISO/IEC ITC 1/SC 31 international standardization group, propose security protocols suitable for the UHF-band passive RFID system using a crypto engine, and analyze its security strength. In addition, we verify that it is possible to implement a tag conforming with the proposed security protocols by presenting concrete command/response pairs and cryptographic method.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.146-154
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• 2009

To suggest effective ways of the management of reptiles in Korea national parks, we applied PIT (passive integrated transponder) tag and radio telemetry research methods in the monitoring of reptiles in Odaesan and Woraksan national parks. We implanted PIT tags into 137 snakes (six species) captured in both the national parks between March 2006 and October 2008 and also radio-tracked two Korean rat snakes (Elaphe schrenckii anomala) from September 2007 to November 2008 in the Woraksan national park. Of total 137 snakes which we had inserted the PIT tag, 17 snakes (12.40%) were recaptured. Based on the PIT tag data of the recapture, we successfully obtained the annual growth rate of Korean cat snakes (Elaphe dione) and Red-tongue pit-viper (Gloydius ussuriensis). Home range of the Korean rat snakes based on the data of radiotracking was estimated as 389,600$m^2$ (MCP: Minimum convex polygon) and 471,800$m^2$ (Kernel 95%) for males and 162,500$m^2$ and 208,700$m^2$ for females. These results suggest that if we apply PIT tag and radio telemetry research methods to manage reptiles in Korea national parks, it could greatly increase our understanding about their basic ecology and as the result, it could allow us to develop better management and conservation ways of reptiles in Korea national parks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.794-804
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• 2008

In this paper, we analyze the performance of probabilistic slotted anti-collision algorithm used in EPCglobal Class-1 Generation-2 (Gen2). To increase throughput and system efficiency, and to decrease tag identification time and collision ratio, we propose new tag anti-collision algorithms, which are FAFQ (fired adjustable flamed Q) algorithm and AAFQ (adaptive adjustable framed Q) algorithm, by using QueryAdjust command. We also propose grouping method based on Gen2 to improve the efficiency of tag identification. The simulation results show that all the proposed algorithms outperform Q algorithm, and AAFQ algorithm performs the best. That is, AAFQ has an increment of 5% of system efficiency and a decrement of 4.5% of collision ratio. For FAFQ and AAFQ algorithm, the performance of grouping method is similar to that of ungrouping method. However, for Q algorithm in Gen2, grouping method can increase throughput and system efficiency, and decrease tag identification time and collision ratio compared with ungrouping method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.1081-1090
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• 2010

$0.18{\mu}m$ CMOS UHF RFID tag frontend is presented in this paper. Several key components are highlighted: the voltage multiplier based on the threshold voltage terminated circuit, the demodulator using current mode, and the clock generator. For standard compliance, all designed components are under the EPC Global Class-1 Generation-2 UHF RFID protocol. Backscatter modulation uses the pulse width modulation scheme. Overall performance of the proposed tag chip was verified with the evaluation board. Prototype Tag Chip dimension is neary 0.77mm2 ; According to the simulation results, the reader can successfully interrogate the tag within 1.5m. where the tag consumes the power about $71{\mu}W$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.872-882
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• 2005

In this paper, we examined the operating principle of a passive tag antenna for RFID system in UHF band. Based on the study, we proposed a novel RFID tag antenna which adopts the inductively coupled feeding structure to match antenna impedance to a capacitively loaded commercial tag chip. The proposed tag antenna consists of microstrip lines on a thin PET substrate for low-cost fabrication. The detail structure of the tag antenna were optimized using a full electromagnetic wave simulator of IE3D in conjunction with a Pareto genetic algorithm and the size of the tag antenna can be reduced up to kr=0.27($2 cm^2$). We built some sample antennas and measured the antenna characteristics such as a return loss, an efficiency, and radiation patterns. The readable range of the tag antenna with a commercial RFID system showed about 1 to 3 m.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.1
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• pp.47-53
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• 2006

Localization is a essential technology for mobile robot to work well. Until now expensive sensors such as laser sensors have been used for mobile robot localization. We suggest RFID tag based localization system. RFID tag devices, antennas and tags are cheap and will be cheaper in the future. The RFID tag system is one of the most important elements in the ubiquitous system and RFID tag will be attached to all sorts of goods. Then, we can use this tags for mobile robot localization without additional costs. So, in this paper, the smart floor using passive RFID tags is proposed and, passive RFID tags are mainly used for identifying mobile robot's location and pose in the smart floor. We discuss a number of challenges related to this approach, such as tag distribution (density and structure), typing and clustering. When a mobile robot localizes in this smart floor, the localization error mainly results from the sensing range of the RFID reader, because the reader just ran know whether a tag is in the sensing range of the sensor. So, in this paper, we suggest two algorithms to reduce this error. We apply the particle filter based Monte Carlo localization algorithm to reduce the localization error. And with simulations and experiments, we show the possibility of our particle filter based Monte Carlo localization in the RFID tag based localization system.