• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.3 s.309
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• pp.50-58
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• 2006

This paper describes the implementation of an efficient Rate-Distortion Optimization algerian to speed up rate control in JPEG2000. While the conventional algorithm determines the rate constant by averaging maximum R-D slope and minimum R-D slope for entire image, the proposed algorithm determines it by using R-D slopes of coding passes located near truncation point. Moreover, the rate allocation in proposed algorithm is conducted about only coding passes excluded from the previous rate allocation. As a result, it can reduce the number of operations required for rate-distortion optimization. The proposed algorithm was implemented in C programing language and was executed on the Altera Excalibur(EPXA4) development board.

• Journal of The Korean Association of Information Education
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• v.20 no.5
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• pp.519-526
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• 2016

MIT App Inventor 2, much like the other block-based programming languages such as Scratch and Alice, is a useful tool that can be utilized to improve the computational thinking skills for students. The coding and the execution of program are done mainly on the computer in Scratch programming, but in App Inventor 2 programming, the students can execute the program and get immediate feedback on the smart-phone in the middle of the programming. Therefore, we can expect better enhanced learning effect. In this study, it has been claimed that the learning of App Inventor2 can strengthen the computational thinking skills of our students by extracting four core concepts of the computational thinking and then showing how these concepts are applied through the learning of App Inventor 2.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2331-2342
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• 2015

In this paper, we design non-linear transmitter and receiver using a uniform channel decomposition (UCD) to take account of inter-cell interference in multi-cell downlink systems. The designed UCD scheme brings forth the same SINR for all sub-channels in each cell. It provides great convenience to modulation/coding process and achieves the maximum diversity gain. The simulation results confirm that it exhibits a lower BER than the conventional method.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.667-670
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• 2007

볼륨 데이터에 대한 압축 기법의 필요성은 데이터 용량의 증가와 네트워크 사용량의 증가와 함께 더불어 증가해 왔다. 현재에는 다양한 압축 기법이 개발돼 있으며, 사용자는 데이터 유형이나 응용 분야에 맞춰 압축 기법을 선택, 적용할 수 있다. 그러나 최근에는 응용 과학자들로부터 생성되는 데이터의 용량이 기하급수적으로 증가했는데, 이렇게 응용과학 분야에서 생성되는 데이터는 대부분 3차원 볼륨 데이터다. 2차원 이미지나 3차원 동영상 데이터의 경우에는 다양한 표준 압축 방식을 사용할 수 있지만 3차원 볼륨 데이터에 적용할 수 있는 방법은 한정돼 있으며, 특히 시간가변(time-varying) 볼륨 데이터에 대한 압축 표준은 거의 존재하지 않는다고 볼 수 있다. 본 논문에서는 시간가변 볼륨 데이터에 대한 압축 방식을 제안한다. 이 방식은 가시화를 목적으로 하는 시간가변 볼륨 데이터의 인코딩을 목적으로 하며, MPEG의 I-프레임과 P-프레임 개념을 사용해서 압축률을 높인다. 본 방식은 시간가변 부동 소수점 데이터(single precision floating-point data)로 구성된 시간가변 볼륨 데이터를 대상으로 하는데, 한 블록 단위의 무작위 복원을 지원하며 Daubechies 웨이블릿 필터와 프레임간의 상관 관계를 사용, 대형 시간가변 볼륨 데이터를 이미지 화질을 보존한다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.283-290
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• 2004

In this paper, a low-power structure for 512 tap FIR filter in MPEG audio algorithm is proposed. By using CSD(Canonic Signed Digit) form filter coefficients and maximum sharing of input signal sample, it is shown that the number of adders of proposed structure can be minimized. To minimize the number of adders, the proposed structure utilizes the 4 steps of sharing, i.e., common input sharing, linear phase symmetric filter coefficient sharing, block sharing for common input, and common sub-expression sharing. Through Verilog-HDL coding, it is shown that reduction rates in the implementation area and relative power consumption of the proposed structure are 60.3% and 93.9% respectively, comparison to those of the conventional multiplier structure.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.2
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• pp.45-55
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• 1994

In this paper, a block based image approximation technique using the Self Affine System(SAS) from the fractal theory is suggested. Each block of an image is divided into 4 tiles and 4 affine mapping coefficients are found for each tile. To find the affine mapping cefficients that minimize the error between the affine transformed image block and the reconstructed image block, the matrix euation is solved by setting each partial differential coefficients to aero. And to ensure the convergence of coding block. 4 uniformly partitioned affine transformation is applied. Variable block size technique is employed in order to applynatural image reconstruction property of fractal image coding. Large blocks are used for encoding smooth backgrounds to yield high compression efficiency and texture and edge blocks are divided into smaller blocks to preserve the block detail. Affine mapping coefficinets are found for each block having 16$\times$16, 8$\times$8 or 4$\times$4 size. Each block is classified as shade, texture or edge. Average gray level is transmitted for shade bolcks, and coefficients are found for texture and edge blocks. Coefficients are quantized and only 16 bytes per block are transmitted. Using the proposed algorithm, the computational load increases linearly in proportion to image size. PSNR of 31.58dB is obtained as the result using 512$\times$512, 8 bits per pixel Lena image.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1667-1670
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• 2005

본 논문에서는 차세대 통신 플랫폼을 위한 PCI Express의 전송계층과 데이터 연결계층의 모든 기능을 지원하는 PCI Express 컨트롤러를 설계하였다. 설계되어진 컨트롤러는 재전송 매커니즘을 효과적으로 지원하기 위해 제안되어진 송신버퍼 구조를 가지고 있다. 이 버퍼 구조는 전송 버퍼와 재전송 버퍼를 한 개의 버퍼로 통합하여 재전송 버퍼의 공간을 유동적으로 할당할 수 있는 방법이다. 또한 설계되어진 컨트롤러의 송신단 전송계층은 제안되어진 버퍼 구조 효과적으로 지원하도록 설계되어 졌다. 설계 되어진 컨트롤러의 각 블록을 효과적으로 관리하기 위해 80C51 마이크로프로세서를 내장하여 PCI Express 프로토콜을 제공하는 프로그램을 코딩하여 포팅하였다. 또한 설계되어진 컨트롤러의 검증을 위해, Host Bridge, 로컬 마스터 디바이스, 로컬 슬레이브 디바이스를 버스 동작 모델로 구성된 테스트 벤치도 제안하였다. 또한 실제 PCI Express 프로토콜 상에서 발생할 수 있는 모든 경우를 발생 하도록 하기 위해, 각 버스 동작 모델을 위한 어셈블러 명령어들을 정의 하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10A
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• pp.968-975
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• 2006

Research about the mode of MIMO that can get a coding benefit at the same time with a diversity benefit using a multiple antenna at the fading channel for a high-speed data transmission have been processed actively But the analysis about the interference of UWB system comes not to consist yet. So this paper analyzed the performance of the interference of UWB system to SFBC-OFDM and SFTC-OFDM system that applied a space block code which has a space diversity characteristic to OFDM system at MIMO channel. We shelved the performance that SFTC-OFDM system is robuster than SFBC-OFDM system under MB-OFDM UWB Interference.

• The KIPS Transactions:PartA
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• v.13A no.7 s.104
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• pp.639-646
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• 2006

Data compression technologies enable us to store and transfer large amount of data efficiently, and become more and more important due to increasing data size and the network traffic. Moreover, as a result of the increase of computing power, volumetric data produced from various applied science and engineering fields has been getting much larger. In this Paper, we present a volume compression scheme which exploits Daubeches wavelet transform. The proposed scheme basically supports lossy compression for 3D volume data, and provides unit-wise random accessibility. Since our scheme shows far lower error rates than the previous compression methods based on Haar filter, it could be used well for interactive visualization applications as well as large volume data compression requiring image fidelity.

• Journal of The Korean Association of Information Education
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• v.19 no.4
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• pp.489-498
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• 2015

In this study, we suggested the contents, teaching and learning method, and assessment types of algorithm education in elementary schools. First, we suggested the algorithm education contents; the expression, understanding, flowcharts, structure, results, correction, and improvement of algorithm. Second, we showed the algorithm teaching and learning methods; algorithm in our daily life, the unplugged activity, block programming and tangible programming. Finally, we analyzed all missions of 'Hour of Code' in Code.org, and suggested the algorithm assessment 4 types, which includes selecting, filling, correcting, predicting of appropriate algorithm.