• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.187-189
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• 2006

최근 지하철이나 버스 등의 교통수단을 이용하기 위해 지불방식의 편리, 지연시간의 단축 등 효율성이 높은 비접촉식 카드를 많이 사용하고 있다. 이러한 비접촉식 스마트 카드를 인증하기 위해서는 스마트카드ID가 스마트카드 단말기 내부에 저장하고 있어야 하며, 스마트카드ID가 변경될 때마다 서버으로부터 전송받아 최신의 정보로 갱신되어야 한다. 교통시스템에서 사용되는 통신매체는 RS-485를 사용하여 38.5Kbps로 통신하고 있고, 그로인해 스마트카드ID를 전송할 때 시간이 많이 소모되고, 스마트카드ID를 전승하는 동안에는 스마트카드 단말기의 사용이 제한되고 있어 단말기가 사용되지 않는 시간에 전송하고 있다. 이러한 교통시스템의 환경에서 점점 더 많아지고 있는 대량의 데이터를 스마트카드 단말기에 빠르게 전송하기 위해 스마트카드ID의 특성을 이용한 인코딩 기법을 적용하여 스마트카드ID의 크기를 줄여 전송함으로써 전송시간을 줄이는 방법을 제안하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.385-387
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• 2004

최근 지하철이나 버스 등의 교통수단을 이용하기 위해 비접촉식 카드를 이용한 IC카드 Reader가 많이 사용되고 있다. 이러한 IC카드 Header는 ID를 인증하기 위한 UserID를 Reader내부에 저장하고 있으며 UserID가 바뀔 때 마다 상위 시스템(서버)으로부터 전송받아 최신의 UserID를 가지고 있어야 한다. 교통시스템에서 사용되는 통신매체는 환경의 특수함으로 인해 낮은 전송속도를 이용하여 통신하고 있고, 그로인해 UserID를 전송할 때 시간이 많이 소모된다. UserID를 전송하는 동안에는 IC카드 Reader의 사용이 제한되기 때문에 UserID는 IC카드 Reader가 사용되지 않는 시간에 전송하고 있다. 많은 양의 UserID를 IC카드 Reader에 빠르게 전송하기 위해 UserID의 특성을 이용한 엔코딩(encoding) 기법을 적용 하여 UserID의 크기를 줄여 전송함으로써 전송시간을 줄이는 방법을 제안하였다.

• Journal of The Korean Association of Information Education
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• v.22 no.4
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• pp.447-455
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• 2018

The purpose of this study is to investigate the effects of SW education using robot based on card coding on learning motivation and attitude of elementary school students. To do this, we conducted 8-hour SW education based on the CT concept of sequence, repetition, event, and control using the Truetrue, which is coded by command card for the 3rd grade of elementary school students. For the experiment, we examined the learning motivation for SW education and the attitude toward SW education based on the robot in advance. As a result, the students' motivation to learn SW education showed a statistically significant improvement. In addition, the attitude toward robot-based SW education improved statistically significantly as "good, convenient, interesting, easy, friendly, active, special, understandable, easy, simple". These results are expected to contribute to the expansion of education through various approaches of SW education.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.1
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• pp.127-132
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• 2007

This paper proposed receding methods for a radix-${\gamma}$ representation of the secret scalar which are resistant to SPA. Unlike existing receding method, these receding methods are left-to-right so they can be interleaved with a left-to-right scalar multiplication, removing the need to store both the scalar and its receding. Hence, these left-to-right methods are suitable for implementing on memory limited devices such as smart cards and sensor nodes

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.605-610
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• 2003

선거를 전자적으로 구성하기 위해서는 비밀성(privacy), 선거권(eligibility) 등과 함께 전체검증(universal verifiability)과 매표방지(receipt-freeness) 속성을 반드시 제공해야 한다. 지금까지 제안된 전자선거 기법은 매표방지와 전체검증을 제공하기 위해 도청 불가능한 채널이라는 물리적인 가정 하에 이루어지거나 하드웨어 장치를 이용하더라도 장치에 대한 신뢰가 가정되었다. 본 논문에서는 믹스 서버나 랜덤마이저의 역할을 스마트카드와 같은 안전한 하드웨어 장치가 하므로 물리적 가정 없이 효율적으로 구현한다. 제안한 시스템은 표를 섞는 과정에서 permutation matrix를 사용하여 증명하므로 증명의 회수가 적고 간단하여 효율적이다. 또한, 지금까지 제안된 대부분의 선거 기법은 ElGamal 암호시스템의 준동형 특성을 이용하여 모든 표를 결합한 다음 해독하여 집계를 계산하는데 이는 이산대수 문제를 효율적으로 해결할 수 있어야 가능했다. 이 논문에서는 ElGamal 암호시스템과 다차잉여 기반 암호알고리즘인 Naccacne 암호알고리즘을 결합하여 표를 인코딩 함으로써 유권자의 수가 많은 선거에 대해서도 다항 시간 내에 집계가 가능하다.

• Journal of The Korean Association of Information Education
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• v.20 no.3
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• pp.283-292
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• 2016

Based on revised 2015 curriculum, diversified SW education methods for elementary school students are researched, developed and applied. However, as most of SW education is based on English text, its coding process may be difficult for low graders of elementary school who are not familiar with English and Math. Under this situation, Kodu game lab based 'icon card board' by which coding could be learnt with ease through game and icon was developed and story activity, coding activity and collaboration activity (SCC) strategy based 17th session SW curriculum was applied and verified. As a result of research, in terms of satisfaction of students for SW class, students more than 86% recognized such class positively and a significant effect was obtained from students' interest level and learning model for coding.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1571-1578
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• 1999

In this paper, we present the Modulator Channel Card and VLSI chip for the Radio Transceiver Unit (RTU) of direct sequence code division multiple access (DS-CDMA) Wireless Local Loop (WLL) System. The Modulator Channel Card is designed and implemented using ASIC's, FPGA's and DSP's. The ASIC, compliance with Common Air Interface specification proposed by ETRI, has 40K gates which is designed to operate at 32MHz, and is fabricated using $0.6\mu\textrm{m}$ CMOS process. The ASIC carries out for I- or Q- phase data channel signal processing at a time, where each data channel processing consists of channel coding, block interleaving, scrambling, Walsh modulation, Pseudo-Noise (PN) spreading, and baseband filtering. The Modulator Channel Card has been integrated as a part of RTU of WLL system and is confirmed that it meets all functional and performance requirements.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.1
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• pp.21-32
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• 2007

Vuillaume-Okeya presented unsigned receding methods for protecting modular exponentiations against side channel attacks, which are suitable for tamper-resistant implementations of RSA or DSA which does not benefit from cheap inversions. The proposed method was using a signed representation with digits set ${1,2,{\cdots},2^{\omega}-1}$, where 0 is absent. This receding method was designed to be computed only from the right-to-left, i.e., it is necessary to finish the receding and to store the receded string before starting the left-to-right evaluation stage. This paper describes new receding methods for producing SPA-resistant unsigned representations which are scanned from left to right contrary to the previous ones. Our contributions are as follows; (1) SPA-resistant unsigned left-to-right receding with general width-${\omega}$, (2) special case when ${\omega}=1$, i.e., unsigned binary representation using the digit set {1,2}, (3) SPA-resistant unsigned left-to-right Comb receding, (4) extension to unsigned radix-${\gamma}$ left-to-right receding secure against SPA. Hence, these left-to-right methods are suitable for implementing on memory limited devices such as smartcards and sensor nodes

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.211-222
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• 2006

The cluster system with shared-nothing storage cannot escape from the problem of skewed request toward specific contents. This paper, therefore, suggests streaming method using MDC (Multiple Description Coding) instead of using single original content; this method is able to cope with skewed request in shared-nothing storage server as well as to continue to provide services in case of the system failure. Also, the system can support adaptive streaming service according to user player type, network status, the load of server, and client.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.901-906
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• 2006

In this paper, we describe the implementation of the digital photo frame system that displays the images coming through the memory card of a digital camera. Each image can be recorded with voice in this system, and a function of the mp3 player is implemented as well. We use Intel PXA255 to control the system and modify the bootloader and linux kernel. Also we adapt device driver for this system. For the realization of image display, voice recording and mp3 playing in the basis of the linux system, we program some of the Microwindows system configuration files and program applications here. This study will be a good example to access the development of the digital photo frame based on the linux system using less-power and high performed embedded processor.