• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.949-950
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• 2008

The intra prediction technique is the one of the key factors to the success of H.264. There are nine optional prediction modes for each $4{\times}4$ luma block and 4 modes for each $16{\times}16$ luma block. To reduce the intra mode bits efficiently, the most probable mode (MPM) is estimated by using the intra modes of the adjacent blocks, since intra modes for neighboring $4{\times}4$ luma blocks are correlated. In this paper, a new method for estimating the MPM is proposed by using the statistical distribution of intra modes of adjacent intra blocks. Experimental results show that the proposed method can achieve a coding gain of about 0.1dB.

• ETRI Journal
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• v.18 no.4
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• pp.229-244
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• 1997

Realization of the economical, reliable, and efficient ATM interface block becomes an important key to development of the ATM switching system when we consider new issues raised recently. In this paper, we summarize requirements for the ATM interface block and present the UNI (User Network Interface)/NNI (Network Node Interface) architecture to meet these requirements. We also evaluate the performance of the multiplexer adopting the various multiplexing schemes and service disciplines. For ATM UNI/NNI interface technologies, we have developed a new policing device using the priority encoding scheme. It can reduce the decision time for policing significantly. We have also designed a new spacer that can space out the clumped cell stream almost perfectly. This algorithm guarantees more than 99 % conformance to the negotiated peak cell rate. Finally, we propose the interface architecture for accommodation of the ABR (Available Bit Rate) transfer capability. The proposed structure that performs virtual source and virtual destination functions as well as a switch algorithm can efficiently accommodate the ABR service.

• Proceedings of the KSEG Conference
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• 2002.04a
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• pp.109-114
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• 2002

Development of a three-dimensional mine visualization model for a section of the mine is addressed first. Discontinuity orientation and location information was taken from this visualization model for use in slope stability analyses. Estimated shear strength properties of discontinuities and mechanical properties of intact rock from the rock mass samples obtained from the mine are discussed next. The third part of the paper is focused on the results obtained for maximum safe slope angles for the section considered of the mine based on block theory analysis conducted under only the gravitational forces using the mapped discontinuities at the mine. Finally, the effects of water that exist in the rock mass, a tension crack, slope face inclination, overall wedge height and double benching on factor of safety of wedge stability are illustrated through limit equilibrium slope stability analyses conducted on a single tetrahedral wedge belonging to potential key block category that exist in the investigated area of the mine.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.3
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• pp.32-45
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• 1998

A partitioned signature file is an enhancement of the signature file that divides all the signatures into blocks in such a way that each block contains the signatures with the same key. Its directory storesall the keys as meta information for avoiding unnecessary block accesses by examming them first before the acture searching of the blocks.. Efficient directory management is very important in large databasse environments since ist size gets larger proportionally to that of the database. In this paper, we first point out the problems in the directory management methods of the previous partitioned signature files, and then present a new one solving them. OUr method offers good features in the followint three aspects: (1) suitability for large database environments, (2) adaptability to dynamic situations, and (3) storage overhead for the directory. Moreover, we can seamlessly integrate it as a subcomponent into previously-developed general-purpose storage engines. These features show that our method is applicableto signature-based access structures for the content-based retrieval in various multimedia applications such as hypermedia systems, digital library systems, multimedia document systems, multimedia mailing systems, and so on.

• Journal of Embryo Transfer
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• v.12 no.3
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• pp.247-251
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• 1997

This research was conducted to observe developmental capacity of the early embryos aggrigated to phytohemagglutinin-M(PHA-M) in the culture of mouse embryos in vitro. The results showed that the development of blastocyst increased to 2-celT >< 2-cell : 68. 9%, 4-cell $\times$4-cell : 92.5% and 8-cell $\times$8-cell : 97.3% in the aggrigated embryos of ICR mouse, and 2-cell $\times$ 2-cell : 90.0%, 4-cell $\times$4-cell : 93.9% and 8-cell $\times$ 8-cell : 100% in the aggrigated embryos of two different strains (ICR $\times$ CBA/J mouse). (Key words : aggrigated embryos, in vitro 2-cell block, phytohemagglutinin-M, blastocyst)

• Journal of Information Processing Systems
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• v.14 no.1
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• pp.101-128
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• 2018

Thanks to its potential in many applications, Blockchain has recently been nominated as one of the technologies exciting intense attention. Blockchain has solved the problem of changing the original low-trust centralized ledger held by a single third-party, to a high-trust decentralized form held by different entities, or in other words, verifying nodes. The key contribution of the work of Blockchain is the consensus algorithm, which decides how agreement is made to append a new block between all nodes in the verifying network. Blockchain algorithms can be categorized into two main groups. The first group is proof-based consensus, which requires the nodes joining the verifying network to show that they are more qualified than the others to do the appending work. The second group is voting-based consensus, which requires nodes in the network to exchange their results of verifying a new block or transaction, before making the final decision. In this paper, we present a review of the Blockchain consensus algorithms that have been researched and that are being applied in some well-known applications at this time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.593-602
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• 2004

We have developed a digital control rod control system not only to improve its performance but also to improve its reliability and speed of response so that it can replace the old fashioned analog system. However, a new developed digital control system should be tested to prove the validity by using any prototype or mock-up before application. The reliability prediction and the reliability block diagram analysis methods were adopted to verify the reliability of the developed hardware. For the case of software, especially fur a new developed control algorithm it has been tested to prove performances and validation by using a dynamic simulator and mock-up of control rod drive mechanism altogether. Here we want to present some key factors regarding to the new developed digital system with some verification procedures.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.5 no.1
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• pp.25-36
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• 1995

Differential Cryptanalysis(DC) and Linear Cryptanalysis(LC) are considered to be efficient attack methods which could be applied to DES and other DES-like private key Cryptosystems. This paper analyzes the DC and LC attack to DES and design a 80-bit block Cipher (80-DES) which could be strong against DC and LC Attack.

• ETRI Journal
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• v.46 no.2
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• pp.175-183
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• 2024

Recently, polar code has attracted the attention of many scholars and has been developed as a code technology in coded-cooperative communication. We propose a polar code scheme based on Plotkin structure and quasi-uniform punching (PC-QUP). Then we apply the PC-QUP to coded-cooperative scenario and built to a new coded-cooperative scheme, which is called PCC-QUP scheme. The coded-cooperative scheme based on polar code is studied on the aspects of codeword construction and performance optimization. Further, we apply the proposed schemes to space-time block coding (STBC) to explore the performance of the scheme. Monte Carlo simulation results show that the proposed cooperative PCC-QUP-STBC scheme can obtain a lower bit error ratio (BER) than its corresponding noncooperative scheme.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.5
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• pp.15-25
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• 2002

In this paper a design of high performance cryptographic processor which implements AES Rijndael algorithm is described. To eliminate performance degradation due to round-key computation delay of conventional processor, the on-the-fly precomputation of round key based on modified round structure is adopted. And on-the-fly round key generator which supports 128, 192, and 256-bit key has modular structure. The designed processor has iterative structure which uses 1 clock cycle per round and supports three operation modes, such as ECB, CBC, and CTR mode which is a candidate for new AES modes of operation. The cryptographic processor designed in Verilog-HDL and synthesized using 0.251$\mu\textrm{m}$ CMOS cell library consists of about 51,000 gates. Simulation results show that the critical path delay is about 7.5ns and it can operate up to 125Mhz clock frequency at 2.5V supply. Its peak performance is about 1.45Gbps encryption or decryption rate under 128-bit key ECB mode.