• Journal of electromagnetic engineering and science
• /
• v.7 no.3
• /
• pp.134-137
• /
• 2007

This paper presents the design of the compact UHF Bandpass filter of CT-type with a novel mixed coupling topology. In further detail, this new coupling structure mathematically equals the transmission zero that enables particularly the better rejection performance in the stopband without increasing the filter's order. To envision this design concept, we fabricated a microstrip filter whose measurement proves to agree with the predicted performance and the suggested coupling structure reduces the overall size, and will be possibly used in the miniaturized UHF apparatus such as the RFID system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.10a
• /
• pp.635-637
• /
• 2012

In Gen-2 Q-algorithm, the value of initial $Q_{fp}$ and weight C is not defined in the standard. If we let the initial $Q_{fp}$ be large or small, the number of empty slot will be large during the initial query round or almost all the slots will be collided, respectively. Also, if the reader selects an inappropriate weight, there are a lot of empty or collided slots. As a result, it is anticipated that the performance will be declined because the frame size does not converge to the optimal point quickly during the query round. In this paper, we analyze how the performances of Gen-2 Q-algorithm will be affected by the weight and initial slot-count size.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.615-617
• /
• 2014

The PS algorithm divides the tags within the identification range of reader into smaller groups by increasing the transmission power incrementally and identifies them. This algorithm uses the fixed frame size at every scan. Therefore, it has problems that the performance of PS algorithm can be variously shown according to the number of tags, frame size, and power level increase. In this paper, we propose an EPS algorithm that allocates the optimal frame size by estimating the number of tags at each scan.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.8
• /
• pp.1450-1456
• /
• 2016

In this paper, we have checked a method of performance evaluation for electronic pedal, which is a core technology of HBD for detecting the axle temperature of high-speed train. As it is practically impossible to conduct train speed test of 500 km/h, we utilize a high speed rotor for evaluating high speed performance of the electronic pedal instead. According to this method, we found that the measurement results by the velocity measuring instrument is similar with the ones from this research through the high speed rotor. In conclusion, it will be possible to conduct reliability evaluation for high speed performance for Beacon, Balise and RFID, which are utilized for transmitting vital information of train control systems through using the rotor.

• Journal of Advanced Navigation Technology
• /
• v.16 no.2
• /
• pp.247-254
• /
• 2012

In this paper, we propose a concatenated diversity system to assure the data transmission reliability between flight type air nodes which move according to their atypical orbit, then its performance is analyzed using computer simulation and it is designed with hdl. The proposed system cannot only improve a bandwidth efficient and coding gain from diversity TCM code but also the reliability of data transmission is high. From the computer simulation result about bit error rate(BER) of the proposed system, we confirm that its BER performance is about 11dB greater than TCM code at $10^{-2}$ and about 11dB greater than space time block code at $10^{-3}$ which has a full diversity gain. In addition, when we compare its BER performance with space time trellis code which has both a diversity gain and a coding gain, the performance of the proposed system is greater than about 1.5dB at $10^{-5}$. Lastly, after designing the proposed system with HDL, we can confirm that the operation result is correct.

• Journal of the Korean Society for information Management
• /
• v.32 no.4
• /
• pp.137-165
• /
• 2015

This study aimed to investigate the period-specific changes (Library 1.0, Library 2.0, Library 3.0 Period) of job factors and performance features in academic libraries. For this, the study categorized an academic library's job into five dimensions: 1) library administration 2) collection development and management 3) information organization 4) information services and 5) information system development and management, After the categorized library's job was defined in detail, the Delphi survey was conducted twice on librarians and professors of library and information science. The result showed that there were many changes in job factors and performance features in academic libraries towards the period of library 2.0 characterized by user participation, sharing and openness and into library 3.0 characterized by social network and semantic web. Library 3.0 is likely to bring about a significant change in user services with ever changing technological advances stemming from library 2.0, such as mobile services, RFID and NFC etc. The finding of the study suggest that library systems need to be continually upgraded in the period of library 3.0.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.2A
• /
• pp.177-183
• /
• 2009

In this paper, we propose an improved anti-collision algorithm. We have designed an anti-collision unit using this algorithm for the 18000-6 Type C Class 1 Generation 2 standard (Gen2). The Gen2 standard uses a Q-algorithm for incremental method on the Dynamic Slot-Aloha algorithm. It has basically enhanced performance over the Slot-Aloha algorithm. Unfortunately, there are several non-clarified parts: initial $Q_{fp}$ value, weighted C, and the ending point of the algorithm. If an incorrect value is selected, it causes degradation in performance. Thus we propose an improved anti-collision algorithm by clearly defining the vague parts of the existing algorithm. Simulation results showed an improved performance of up to 34.8% using an optimized value of C and the initial $Q_{fp}$ value. With the ending condition, performance is 34.7%. The anti-collision unit is designed using the Verilog HDL. The module was synthesized using Synopsys' Design Compiler and the TSMC $0.2{\mu}m$ standard cell library. The synthesized result yielded 3,847 gates, and was guaranteed under the proposed working frequency of 19.2MHz.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.1
• /
• pp.87-92
• /
• 2020

Various devices, which are powerful computer and low-performance sensors, is connected to IoT network. Accordingly, applying mutual authentication for devices and data encryption method are essential since illegal attacks are existing on the network. But cryptographic methods such as symmetric key and public key algorithms, hash function are not appropriate to low-performance devices. Therefore, this paper proposes blockchain-based lightweight IoT mutual authentication protocol for the low-performance devices.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.8 no.5
• /
• pp.285-293
• /
• 2013

The procedure of the arbitration which is the tag collision is essential because the multiple tags response simultaneously in the same frequency to the request of the Reader. This procedure is known as Anti-collision and it is a key technology in the RFID system. In this paper, we propose the Bit Pattern Prediction Algorithm(BPPA) for the efficient identification of the multiple tags. The BPPA is based on the tree algorithm using the time slot and identify the tag quickly and efficiently using accurate bit pattern prediction method. Through mathematical performance analysis, We proved that the BPPA is an O(n) algorithm by analyzing the worst-case time complexity and the BPPA's performance is improved compared to existing algorithms. Through MATLAB simulation experiments, we verified that the BPPA require the average 1.2 times query per one tag identification and the BPPA ensure stable performance regardless of the number of the tags.

• 한국ITS학회:학술대회논문집
• /
• 2008.11a
• /
• pp.519-524
• /
• 2008

In this paper, we mainly describe the development of exclusive u-device essentially required to implement new ITS services (taxi call service, service for transportation vulnerable, transport information service, walker's navigator, electronic payment service, call information service etc.). To design this device, Samsung main CPU S3C2440A was selected and large memories (ROM and RAM) which are required for new ITS services are applied. In addition, all of GPS, RFID module, Wi-Fi and Bluetooth functions are included to develop an exclusive device indispensable in the ubiquitous society. For this, in this paper, we first examined detailed design of an exclusive u-device development, and based on the designed contents, the performance of a realized u-device was evaluated. If services are created by linking new ITS services with relevant public institutions or companies, based on application of the exclusive u-device developed as above, they would be expanded to a new blue ocean, expectedly resulting in a big spillover effect in local societies.