• Computational Structural Engineering
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• v.4 no.1
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• pp.42-43
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• 1991

균열성암반의 모형화 기술은 계속적으로 보완발전되어 UDEC이 개발되었으며, 현재 UDEC의 최신판은 블록 내부를 다시 유한차분요소로 분할하여 블록의 소성거동(Mohr-Coulomb Model) 및 쪼개짐을 고려할 수 있고, 절리면에서의 유체흐름 및 유압의 발생, 그리고 열응력 해석 등 평면변형 문제의 정적해석과 지진 및 폭발하중을 고려한 동적해석이 가능하다. UDEC은 전처리 기능이 뛰어나 최소한의 입력데이타로써 전체 모형의 데이타를 자동생성시키며 절리면의 통계학적 자동생성 및 터널형상의 자동생성도 가능하다. UDEC은 실용적인 보강요소를 구비하여 Rock Bolt 뿐만 아니라 그라우트를 고려한 Cable Bolt를 모형화할 수 있으며 국부적인(Key Block)보강으로써 불연속체 전체의 안정을 검토할 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.860-868
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• 2011

Feistel and SPN are the two main structures in a block cipher. Feistel is a symmetric structure which has the same structure in encryption and decryption, but SPN is not a symmetric structure. In this paper, we propose a SPN block cipher so called SSB which has a symmetric structure in encryption and decryption. The proposed SSB is composed of the even numbers of N rounds. Each round consists of a round key addition layer, a subsitution layer, a byte exchange layer and a diffusion layer. The subsitution layer of the odd round is inverse function of one of the even round. And the diffusion layer is a MDS involution matrix. The differential and linear attack probability of SSB is $2^{-306}$ which is same with AES. The proposed symmetric SPN block cipher SSB is believed to construct a safe and efficient cipher in Smart Card and RFID environments which is in limited hardware and software resources.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.117-122
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• 2000

The fractal image compression is based on the self-similarity that some area in an image is very similar to others. This compression method offers high compression ratio and fast decompression, but it has very long encoding time. To cut-off the encoding time, most researches give a restriction on domain blocks to be compared with a range block or make an effective search sequence of the domain blocks for a range block. However, most of them take much encoding time yet. In this research, we propose an algorithm that greatly reduces the encoding time by considering the coherence between range blocks. This algorithm first classifies all range blocks into some groups using the coherence between range blocks, and then searches corresponding domain blocks only for the key block of each group. If this scheme is joined in a prior work of the other fractal compression algorithm, it will give a great effectiveness to encoding time.

• Journal of the Korea Society for Simulation
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• v.25 no.2
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• pp.41-49
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• 2016

Counter Fire Operations can be characterized as having a system of systems that key features include situational awareness, command and control systems and highly responsive strike achieved by precision weapons. Current modeling methodology cannot provide an appropriate methodology for a system of systems and utilizes modeling and simulation tools to implement analytic options which can be time consuming and expensive. We explain developing methodology and tools for the effectiveness analysis of the counter fire operations under Network Centric Warfare Environment and suggest how to support a efficient decision making with the methodology and tools. Theater Counter Fire Operations tools consist of Enemy block, ISR block, C2 block and Shooter block. For the convenience of using by domain expert or non simulation expert, it is composed of the environments that each parameter and algorithm easily can be altered by user.

• Journal of Broadcast Engineering
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• v.4 no.1
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• pp.76-85
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• 1999

The degradation of image quality by block loss is more serious in fractal coded images with the error propagation due to mapping from the lost blocks than in DCT coded images. Therefore. a new algorithm is presented for recovering the blocks lost in the transmission through the lossy network as A TM network of the images coded by Jacquins fractal coding. Jacquins fractal code is divided into two layers of header code and main code according to its importance. The key technique of the proposed BLRA (block loss recovery algorithm) is a fractal extrapolation that estimates the lost pixels by using the contractive mapping parameters of the neighboring range blocks whose characteristics are similar to a lost block. The proposed BLRA is applied to the lost blocks in the iteration of decoding. Some experimental results show the proposed BLRA yields excellent performance in PSNR as well as subjective quality.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.203-211
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• 2016

The genetic code is a key to bio-informatics and to a science of biological self-organizing on the whole. Modern science faces the necessity of understanding and systematically explaining mysterious features of ensembles of molecular structures of the genetic code. This paper is devoted to symmetrical analysis for genetic systems. Mathematical theories of noise-immunity coding and discrete signal processing are based on Jacket matrix methods of representation and analysis of information. Both of the RNA and Jacket Matrix property also have the Element(Block) - wise Inverse Matrices. These matrix methods, which are connected closely with relations of symmetry, are borrowed for a matrix analysis of ensembles of molecular elements of the genetic code. This method is presented for its simplicity and the clarity with which it decomposes a Jacket Matrix in terms of the genetic RNA Codon.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1118-1122
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• 2003

In this paper, we propose a new invisible digital watermarking scheme based on wavelet transform using singular value decomposition. Embedding process is started by decomposing the lowest frequency band image with 3${\times}$3 block among which we define the watermark block chosen by a key set; entropy and condition number of the block. A watermark is embedded in the singular values of each watermark blocks. This provides a robust watermarking in lowest possible time-frequency domain. To detect the watermark, we are locally modeling an attack as 3${\times}$3 matrices on the watermark blocks. Combining with the SVD and the attack matrices, we estimate watermark set corresponding to the watermark blocks. In each watermark block, we determine an optimal watermark which is justified by the T-testing. A numerical experiment shows that the proposed watermarking scheme efficiently detects the watermarks from several JPEG attacks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.4
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• pp.67-75
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• 2001

3GPP proposed f8 and f9 algorithms based on the block cipher KASUMI to provide the data confidentiality and integrity over a radio access link for IMT-2000(W-CDMA). Also 3GPP proposed Milenage algorithm based on the block cipher Rijndael to provide an example set for 3GPP authentication and key generation functions. In order to analyze the security of 3GPP algorithms, we must go ahead an analysis of security of KASUMI and Rijndael. Since S-box is an important point of security of block cipher, in this paper we analyze the S-boxes of KASUMI and Rijndael and compare the S-boxes of KASUMI with the S-box of Rijndael. Although KASUMI S9-box is bad for AC and SAC, we find that AC of KASUMI FI function containing S7-box and S9-box is equal to AC of Rijndael S-box and SAC of KASUMI FI function is better than SAC of Rijndael S-box.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.17-24
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• 2010

A differential fault attack(DFA) is one of the most efficient side channel attacks on block ciphers. Almost all block ciphers, such as DES, AES, ARIA, SEED and so on., have been analysed by this attack. In the case of the known DFAs on SEED, the attacker induces permanent faults on a whole left register of round 16. In this paper, we analyse SEED against DFA with differential characteristics and addition-XOR characteristics of the round function of SEED. The fault assumption of our attack is that the attacker induces 1-bit faults on a particular register. By using our attack, we can recover last round keys and the master key with about $2^{32}$ simple arithmetic operations. It can be simulated on general PC within about a couple of second.

• Journal of the Korea Society of Computer and Information
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• v.6 no.2
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• pp.90-96
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• 2001

The development of network and the other communication-network can generate serious social problems. So. it is highly required to control security of network. These problems related security will be developed and keep up to confront with anti-security part such as hacking. cracking. In this paper. the proposed multiple nonlinear S-box function which is capable to cipher regardless of key distribution or key-length for these definite problem is proposed and designed in hardware. The proposed multiple nonlinear S-box function increase secret level from using a nonlinear function in multiply for key data utilized in cryptography that generates MDP and MLP in maximum is proposed to prevent cryptography analysis. The designed the multiple nonlinear S-box function in this paper performed synthesization and simulation using Synopsys Ver. 1999.10 and VHDL