• Journal of Biomedical Engineering Research
• /
• v.28 no.3
• /
• pp.325-331
• /
• 2007

Personal identification is essential for the automatic measurement of biosignal information in home healthcare systems. Personal identification is usually achieved with passive radio frequency identification (RFID), which does little more than store a unique identification number. However, passive RFID is not ideal for automatic identification. We present a user identification system based on radio signal strength indication (RSSI) using ZigBee for active RFID tags. Personal identification is achieved by finding the largest RSSI value from aggregated beacon messages that are periodically transmitted by active RFID tags carried by users. Obtaining reliable person!'.! identification without restricting the orientation requires a certain distance between the closest active RFID tag from the ZED and the second closest tag. The results show that the closest active RFID tag from the ZED and the second closest tag must be at least 70 cm apart to achieve reliable personal identification.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1606-1611
• /
• 2005

The goal of this paper is to develop a self localization of mobile robot using UHF RFID landmark. We present landmark, a location sensing archetype system that uses UHF Radio Frequency Identification (UHF RFID) technology for locating objects inside buildings. The major advantage of landmark is that it improves the overall accuracy of locating objects by utilizing the concept of reference tags. Based on experimental analysis, we demonstrate that passive UHF RFID is a viable and cost-effective candidate for indoor location sensing. We conduct a series of experiments to evaluate performance of the positioning of the landmark System. In the standard setup, we place RF Reader which has two antennas and 25 tags in our lab. This research uses the assumption-based coordinates (ABC) algorithm[3] for determining the localization of robot. Also, we show how Radio Frequency Identification (UHF RFID) can be used in robot-assisted indoor navigation for the visually impaired. The experiments illustrate that passive UHF RFID tags can act as reliable landmark that trigger local navigation behaviors to achieve global navigation objectives.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.44 no.4 s.316
• /
• pp.45-49
• /
• 2007

The isolation between transmitter and receiver has been a critical problem in a pulse-modulated RFID (Radio Frequency Identification) system where transmitter and receiver use the identical frequency. A method using a switch, a mixer, a BPF (band-pass filter), and an additional oscillator in the transmitter is proposed to improve the isolation between transmitter and receiver in an RFID system. The Proposed system up-converts the outgoing wave from a frequency different from the received signal and improves the isolation. The proposed method provided additional 20 dB improvement on the isolation.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.4
• /
• pp.61-68
• /
• 2011

Recently arithmetic circuit of lightweight AES symmetric key algorithm that can apply to passive tag have been developed, then security protocol of RFID system using AES symmetric encryption techniques have been proposed. This paper proposed security enhancement protocol of RFID system using lightweight AES arithmetic circuit and random number generator of passive tag. The proposed protocol have AES algorithm and random number generator at server, reader, tag, and transmit encrypted message by separate secret key using random number at each session. The mutual authentication of tag and reader used reader random number and tag random number. As a result, proposal protocol reduce authentication steps of the existing mutual authentication protocol, and reduce amount of computation of tag, and demonstrate as secure protocol to every attack type of attacker by decrease communication step of Air Zone.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.721-724
• /
• 2007

Radio Frequency IDentification (RFID) is increasingly popular technology with many application. The majority of applications of RFID deployed in supply-chain management. In this paper, we present a wireless RFID glove in interactive learning method. Objects tagged with a small passive RFID tag, can be sensed at short ranges by using wireless RFID glove. We describe the wireless RFID glove prototype, and present some interactive learning programs and games.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1797-1801
• /
• 2005

SLAM(Simultaneous localization and mapping) and AI(Artificial intelligence) have been active research areas in robotics for two decades. In particular, localization is one of the most important issues in mobile robot research. Until now expensive sensors like a laser sensor have been used for the mobile robot's localization. Currently, as the RFID reader devices like antennas and RFID tags become increasingly smaller and cheaper, the proliferation of RFID technology is advancing rapidly. So, in this paper, the smart floor using passive RFID tags is proposed and, passive RFID tags are mainly used to identify the mobile robot's location on the smart floor. We discuss a number of challenges related to this approach, such as RFID tag distribution (density and structure), typing and clustering. In the smart floor using RFID tags, because the reader just can senses whether a RFID tag is in its sensing area, the localization error occurs as much as the sensing area of the RFID reader. And, until now, there is no study to estimate the pose of mobile robot using RFID tags. So, in this paper, two algorithms are suggested to. We use the Markov localization algorithm to reduce the location(X,Y) error and the Kalman Filter algorithm to estimate the pose(q) of a mobile robot. We applied these algorithms in our experiment with our personal robot CMR-P3. And we show the possibility of our probability approach using the cheap sensors like odometers and RFID tags for the mobile robot's localization on the smart floor.

• Journal of information and communication convergence engineering
• /
• v.5 no.2
• /
• pp.150-154
• /
• 2007

Transponders of RFID system are classified as active or passive depending on the type of power supply they use. In passive transponders the data carrier has to obtain its power from the induced voltage. The induced voltage is converted into direct current using a low loss bridge rectifier and then smoothed. In practice, the induced voltage in the transponder coil is variable according to the coupling coefficient k and the load resistance ($R_L$). Therefore, the rectified voltage is unstable and the transponder of RFID is unstable sometimes. In this paper, a voltage-dependent shunt resistor ($R_s$) circuits are designed and inserted in parallel with the load resistance of RFID transponder in order to improve the stability of power.

• ETRI Journal
• /
• v.36 no.1
• /
• pp.141-150
• /
• 2014

A fully integrated CMOS security-enhanced passive (SEP) tag that compensates the security weakness of ISO/IEC 18000-6C is presented in this paper. For this purpose, we propose a security-enhanced protocol that provides mutual authentication between tag and reader. We show that the proposed protocol meets the security demands of the ongoing international standard for RFID secure systems, ISO/IEC 29167-6. This paper fabricates the SEP tag with a 0.18-${\mu}m$ CMOS technology and suggests the optimal operating frequency of the CMOS SEP tag to comply with ISO/IEC 18000-6C. Furthermore, we measure the SEP tag under a wireless environment. The measured results show that communications between the SEP tag and reader are successfully executed in both conventional passive and SEP modes, which follow ISO/IEC 18000-6C and the proposed security enhanced protocol, respectively. In particular, this paper shows that the SEP tag satisfies the timing link requirement specified in ISO/IEC 18000-6C.

• Journal of information and communication convergence engineering
• /
• v.9 no.4
• /
• pp.441-446
• /
• 2011

Radio frequency identification (RFID) tags are cheap and simple devices that can store unique identification information and perform simple computation to keep better inventory of packages. Security protocol for RFID tags is needed to ensure privacy and authentication between each tag and their reader. In order to accomplish this, in this paper, we analyzed a lightweight privacy and authentication protocol for passive RFID tags.

• 한국정보통신설비학회:학술대회논문집
• /
• 2008.08a
• /
• pp.469-472
• /
• 2008

In this paper, we discuss the recent trends on the passive UHF RFID tag chip design techniques and several important system parameters. We also summarize link budget studies on both conventional and modem UHF RFID communications. The paper highlights the reverse link limited case, which has known to be the minor concern if reader continuous wave (CW) can reach the tag in sufficient level. This makes sense when the tag sensitivity is rather high (over 10-12${\mu}W$); however, since the tag chip fabrication technologies have been developed by time, the tag chip threshold levels are now less-dominant in determining link margin. If the tag limitation can be alleviated, the forward link limited case can be resolved; thus, we rather focus on the path-loss problem. Since the path-losses are still exist in both forward and reverse links, and it can be doubled while CW travels the reader-tag-reader path because forward link and reverse link are on the same distance. Consider if reader receiver sensitivity is very high in the worst case. In this case, weaken tag response (i.e., backscatters) cannot reach the level that reader receiver can process tag data; bit-error rate can be higher. Overall, backscatter levels should be high enough so that reader receiver can correctly function. After discussing link budget, we carried out practical measurements on fading effects between two circularly polarized UHF RFID antennas in a small scale area.