• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7C
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• pp.697-705
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• 2009

This paper presents the theoretical tag-reading speed in the ASK and the PJM mode of a 13.56MHz RFID system which have been adopted in the international standard ISO 18000-3, along with simulation results to support the mathematical analysis. Through the analysis using the number of tag-dependent Q-algorithm, which was known to give relatively fast reading speed, we not only derive the number of slots to read out given tags, but compare the reading speeds of the ASK with that of the PJM mode. Moreover, we present the numerical comparison of two modes which bring the equivalent results as in the theoretical one.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.27-34
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• 2006

This paper has implemented a very small($1.4{\times}2.8[Cm^2]$) 13.56[MHz] RFID reader ensuring machine ID recognition correctly in a noise space of Tag-to-Reader within 3Cm. For operation of the RFID system, at first, this paper has designed the loop antenna of a reader and the fading model of back-scattering on microwave propagation following to 13.56[MHz] RFID Air Interface ISO/IEC specification. Secondly, this paper has proposed the automatically path selected RF switching circuit and the firmware operation relationship by measuring and analyzing the very small RFID RF issues. Finally, as a very small reader main body, this paper has shown the DSP board and software functions made for extraction of $1{\sim}2$ machine ID information and error prevention simultaneously with carrying of 13.56[MHz] RFID signals that the international standard specification ISO/IEC 18000-3 defined.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1500-1510
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• 2007

In recent, rapid and accurate processing for logistics have been required, according as logistics has grown dramatically. Especially, identifying, locating, or tracking objects in ports are important, because ports are gateways to extended markets. In this paper, we describe the design and implementation of a smart tag system for ubiquitous port logistics. Our solution consists of three parts: an active RFID to identify objects, an electronic container seal to charge with security of containers, and a RTLS system to locate objects. Because identification technology for logistics can be read by heterogenous systems, compliance with the international standard is one of the most critical issues. This paper introduces the method to maintain compliance with ISO, and conducts some verifications. In addition, we analyze the system performance such as lifetime, identification rate, and time for multiple tag identification.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.77-83
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• 2011

In this paper, we present the design procedure of the synchronizer and the demodulator of a 13.56MHz RFID PJM tag, which was standardized in ISO 18000-3 mode 3. We optimize the algorithms in order to minimize the number of registers and implement them based on international standard. The designed module is simulated by Modelsim and FPGA. The synchronizer is composed of 3 correlators that is implemented by 1,024(16bit ${\times}$ 64cycle) registers. The demodulator is composed of 2 correlators that is implemented by 128(2bit ${\times}$ 64cycle) registers. The simulation performed with the demodulator integrated with the synchronizer shows that it works at about 87% success rate with the test data of SNR -2dB and 100% with those of SNR 4dB.

• ETRI Journal
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• v.33 no.4
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• pp.528-536
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• 2011

In this paper, we analyze the location accuracy of real-time locating systems (RTLSs) in multipath environments in which the RTLSs comply with the ISO/IEC 24730-2 international standard. To analyze the location error of RTLS in multipath environments, we consider a direct path and indirect path, in which time and phase are delayed, and also white Gaussian noise is added. The location error depends strongly on both the noise level and phase difference under a low signal-to-noise ratio (SNR) regime, but only on the noise level under a high SNR regime. The phase difference effect can be minimized by matching it to the time delay difference at a ratio of 180 degrees per 1 chip time delay (Tc). At a relatively high SNR of 10 dB, a location error of less than 3 m is expected at any phase and time delay value of an indirect signal. At a low SNR regime, the location error range increases to 8.1 m at a 0.5 Tc, and to 7.3 m at a 1.5 Tc. However, if the correlation energy is accumulated for an 8-bit period, the location error can be reduced to 3.9 m and 2.5 m, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.35-46
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• 2006

When an RFID reader attempts to read the tags, interference might occur if the neighboring readers also attempt to communicate with the same tag at the same time or the neighboring readers use the same frequency simultaneously. These interferences cause the RFID reader collision. When the RFID reader collision occurs, either the command from the reader cannot be transmitted to the tags or the response of the tags cannot receive to the reader correctly, Therefore, the international standard for RFID and some papers proposed the methods to reduce the reader collision. Among those, Colorwave and Enhanced Colorwave is the reader anti-collision algorithm using the frame slotted ALOHA based a TDM(Time Division Multiplex) and are able to reduce the reader collision because theses change the frame size according to a collision probability. However, these can generate the reader collisions or interrupt the tag reading of other readers because the reader that collides with another reader randomly chooses a new slot in the frame. In this paper, we propose a new RFID reader anti-collision algorithm that each reader monitors the slots in the frame and chooses the slot having the minimum occupation probability when the reader collision occurs. Then we analyze the performance of the proposed algorithm using simulation tool.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.46-52
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• 2014

In this paper, we present a design of meander type microstrip patch antenna which has the best quality in RFID approved international standard of 910MHz broadband, usable in metal environment. In order to be fit into the commercial tag chip on the antenna, a square shaped feeder is installed on the main body as well as in the main body. In addition, a multi meander type patching element was designed in order to reduce the main body effectively. Three antennae, Cases 1, 2 and 3, were designed and compared in the areas of broad band width, effectiveness or recognition distance according to their sizes and number of folds. The measurement result of Case 3 was determined to be the best. It was confirmed that mostly the efficiency and characteristic gain change due to antenna size and number of folds in meander type influenced the antenna recognition distance.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.85-94
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• 2008

When an RFID reader uses the same frequency or adjacent frequency with neighbor readers, the interference might occur. These interferences cause the RFID reader collision and errors during tag recognition. Therefore, the international standard for RFID and some papers proposed the methods to reduce the reader collision. The reader interference is closely related to the distance between the readers haying interference and used frequency band. In the previous RFID reader anti-collision algorithms, the location of readers inducing interference which is closely related to interference of readers is not considered. Only the reader collision is tried to reduce through frequency transfer after collisions occur or modification of frame size in relation to collision probability based a TDM(Time Division Multiplex). In this paper, the genetic algorithm using two-dimensional chromosome which reflect readers' location is proposed to prevent reader collision effectively. By executing evolutionary operation with two-dimensional chromosome, the location information having influence on reader interference can be used. The repair operation in the proposed algorithm makes all reader stably recognize their tags.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.231-239
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• 2008

USN and RFID, as new technologies for realization of ubiquitous computing, are closely related with each other technically. Nevertheless, these technologies are recognized as a separate research topic, and there are few researches on technical convergence of the two research areas. In this paper, we propose an efficient processing method of various kinds of sensor data which are used in USN environment to provide efficiency from the view point of not only convergence of USN and RFID technologies but also cost and extensibility. Especially, we propose a method of conversion of various sensor data into EPC data format which can be handled in a RFID middleware. Using the proposed method, RFID middleware systems based on international standard specification can handle not only RFID tag data but also general sensor data efficiently, and various types of ubiquitous application services can be implemented at low cost and in a short time.

• The Korean Journal of Archival Studies
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• no.67
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• pp.99-138
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• 2021

In the era of big data, analyzing not only structured data but also unstructured data is emerging as an important task. Official documents produced by government agencies are also subject to big data analysis as large text-based unstructured data. From the perspective of internal work efficiency, knowledge management, records management, etc, it is necessary to analyze big data of public documents to derive useful implications. However, since many of the public documents currently held by public institutions are not in open format, a pre-processing process of extracting text from a bitstream is required for big data analysis. In addition, since contextual metadata is not sufficiently stored in the document file, separate efforts to secure metadata are required for high-quality analysis. In conclusion, the current official documents have a low level of machine readability, so big data analysis becomes expensive.