• Review of KIISC
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• v.19 no.2
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• pp.53-62
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• 2009

최근 금융권을 포함한 여러 분야에서 스마트카드의 활용이 급증함에 따라 IC 칩을 내장한 카드의 부채널 공격에 대한 안전성이 이슈가 되고 있다. 부채널 공격이란 IC 카드와 같은 저 전력의 정보보호 장치에 암호 알고리듬을 구현하였을 때 누출되는 연산 시간, 소비 전력, 전자파 등의 부채널 정보를 이용하여 구현된 암호 알고리듬의 비밀 정보를 알아내는 공격 방법이다. Kocher에 의해 부채널 공격이 소개된 이후, 많은 연구 그룹들에 의해 이론적인 연구와 실험적인 연구가 이루어져 왔다. 본 고에서는 시파 분석 공격, 전력 분석 공격, 전자파 분석 공격, 오류 분석 공격 등의 다양한 부채널 공격 방법들과 최근까지의 부채널 공격 실험 동향에 대해서 소개하고 국내외 연구 그룹들에 의해 진행된 실험 결과들을 고찰한다. 또한, 보유하고 있는 부채널 공격에 필요한 실험 장비와 지금까지의 부채널 공격 실험 결과들을 소개한다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2968-2970
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• 2000

시계열(time series)이란 한 사상 또는 여러 사상에 대하여 시간의 흐름에 따라 일정한 간격으로 이들을 관측하여 기록한 자료를 말한다. 이러한 시계열은 어떠한 경제현상이나 자연현상에 관한 시간적 변화를 나타내는 역사적 계열(historical series)이므로 어느 한 시점에서 관측된 시계열자료는 그 이전까지의 자료들에 주로 의존하게 된다. 따라서 시계열분석을 통한 예측에서는 과거의 자료들을 분석하여 법칙성을 발견해서 이를 모형화하여 추정하고. 이 추정된 모형을 사용하여 미래에 관측될 값들을 예측하게 된다. 본 연구에서는 ARMA (p, q)모형 (autoregressive moving-average model)을 이용하여 시계열 데이터를 분석하며 계수의 추정에는 Levinson-Durbin 알고리듬과 Newton-Raphson Method를 이용한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.8
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• pp.849-856
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• 2014

This paper proposes a new efficient CFAR algorithm. The structure of the proposed CFAR is relatively simple as compared with the OS-CFAR or ML-CFAR which are considered to deal with the nonhomogeneous environment such as clutter and multiple targets. The proposed algorithm is effectively applied to the radar signal processor with reduced computation burden. The relationship between the threshold and PFA of the proposed CFAR is derived analytically. The CFAR loss of the proposed CFAR algorithm is compared with CA-CFAR and OS-CFAR based on both SNR and ADT(Average Detection Threshold).

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.11
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• pp.116-122
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• 1998

We propose a spatially adaptive image interpolation algorithm, which can restore high frequency details in the original high resolution image. In order to apply the regularization approach to the interpolation procedure, we first present a two-dimensional separable image degradation model for a low resolution imaging system. According to the model, we propose a regularized spatially adaptive interpolation algorithm by using five different constraints. We also analyze convergence of the proposed algorithm, and provide some experimental results to compare the proposed algorithm with its nonadaptive version.

• Journal of the Korea Society of Computer and Information
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• v.9 no.1
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• pp.87-93
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• 2004

In the design of mobile wireless communication network, BSC(Base Station Location), BSC(Base Station Controller) and MSC(Mobile Switching Center) are the most important parameters. Designing base station location, the cost must be minimized by combining various, complex parameters. We can solve this Problem by combining optimization algorithm, such as Simulated Annealing, Tabu Search, Genetic Algorithm, Random Walk Algorithm that have been used extensively for global optimization. This paper shows the 4 kinds of algorithm to be applied to the optimization of base station location for communication system and then compares, analyzes the results and shows optimization process of algorithm.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.1
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• pp.33-41
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• 2002

In this paper, we present a frequency weighted model reduction using LMIs for minimizing the H$\infty$ weighted model error compared with the methods of frequency weighted balanced truncation and frequency weighted Hankel norm approximation. The proposed algorithm, its form is equal to the sufficient condition of performance preserving controller approximation, is based on an iterative two-step LMI scheme induced from bound real lemma. So, it can be applied to the problem of the performance preserving controller approximation. The controller reduction is useful in a practical control design and ensures its easy implementation and high reliability The validity of the proposed algorithm is shown through numerical examples. Additionaly, we extend the proposed algorithm to performance preserving controller approximation by applying to the HIMAT(highly maneuverable aircraft technology) system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8A
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• pp.784-789
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• 2006

In this paper, we propose a bitwise information decomposition algorithm for an M-PSK signal based on the Max-Log-MAP algorithm. In order to obtain the algorithm, we use a coordinate transformation from M-PSK to M-PAM signal space. Using the proposed algorithm, we analyze the performance of a Turbo iterative decoding method. The proposed algorithm can be applicable not only for a communication with PSK and iterative decoding method but for adaptive modulation and coding system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.196-198
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• 2003

In this paper, Rijndal cipher algorithm is implemented by a hardware. It is selected as the AES(Advanced Encryption Standard) by NIST. The processor has structure that round operation divided into 2 subrounds and subrounds are pipelined to calculate efficiently. It takes 5 clocks for one-round. The AES-128 cipher algorithm is implemented for hardware by ALTERA FPGA, and then, analyzed the performance. The AES-128 cipher algorithm has approximately 424 Mbps encryption rate for 166Mhz max clerk frequency. In case of decryption, it has 363 Mbps decryption rate for 142Mhz max clock frequency.

• Korean Journal of Remote Sensing
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• v.18 no.2
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• pp.107-116
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• 2002

A hybrid image segmentation algorithm is proposed which integrates edge-based and region-based techniques through the watershed algorithm. First, by using mean curvature diffusion coupled to min/max flow, noise is eliminated and thin edges are preserved. After images are segmented by watershed algorithm, the segmented regions are combined with neighbor regions. Region adjacency graph (RAG) is employed to analyze the relationship among the segmented regions. The graph nodes and edge costs in RAG correspond to segmented regions and dissimilarities between two adjacent regions respectively. After the most similar pair of regions is determined by searching minimum cost RAG edge, regions are merged and the RAG is updated. The proposed method efficiently reduces noise and provides one-pixel wide, closed contours.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.75-84
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• 2008

Recently, the straightforward CRT-RSA was shown to be broken by fault attacks through many experimental results. In this paper, we analyze the fault attacks against CRT-RSA and their countermeasures, and then propose a new fault infective method resistant to the various fault attacks on CRT-RSA. In our CRT-RSA algorithm, if an error is injected in exponentiation with modulo p or q, then the error is spreaded by fault infective computation in CRT recombination operation. Our countermeasure doesn't have extra error detection procedure based on decision tests and doesn't use public parameter such as e. Also, the computational cost is effective compared to the previous secure countermeasures.