• Geomechanics and Engineering
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• v.15 no.1
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• pp.677-686
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• 2018

Aimed at serious casing damage problem during the process of oilfield development by injecting water, based on seepage mechanics, fluid mechanics and the theory of rock mechanics, the multi-physics coupling theory was also taken into account, the mathematical model for production of petroleum with water flooding was established, and the method to solve the coupling model was presented by combination of Abaqus and Eclipse software. The Q9G3 block in Jibei oilfield was taken for instance, the well log data and geological survey data were employed to build the numerical model of Q9G3 block, the method established above was applied to simulate the evolution of seepage and stress. The production data was imported into the model to conduct the history match work of the model, and the fitting accuracy of the model was quite good. The main mechanism of casing damage of the block was analyzed, and some wells with probable casing damage problem were pointed out, the displacement of the well wall matched very well with testing data of the filed. Finally, according to the simulation results, some useful measures for preventing casing damage in Jibei oilfield was proposed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.285-287
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• 2014

This paper describes a design of area-efficient/low-power cryptographic processor for lightweight block cipher algorithm HIGHT which was approved as a cryptographic standard by KATS and ISO/IEC. The HIGHT algorithm which is suitable for the security of IoT(Internet of Things), encrypts a 64-bit plain text with a 128-bit cipher key to make a 64-bit cipher text, and vice versa. For area-efficient and low-power implementation, we adopt 32-bit data path and optimize round transform block and key scheduler to share hardware resources for encryption and decryption.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.777-779
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• 2014

The LEA(Lightweight Encryption Algorithm) is a 128-bit high-speed/lightweight block cipher algorithm developed by National Security Research Institute(NSRI) in 2012. The LEA encrypts plain text of 128-bit using cipher key of 128/192/256-bit, and produces cipher text of 128-bit, and vice versa. To reduce hardware complexity, we propose an efficient architecture which shares hardware resources for encryption and decryption in round transformation block. Hardware sharing technique for key scheduler was also devised to achieve area-efficient and low-power implementation. The designed LEA cryptographic processor was verified by using FPGA implementation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.15-25
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• 2011

A differential fault analysis(DFA) is one of the most important side channel attacks on block ciphers. Most block ciphers, such as DES, AES, ARIA, SEED and so on., have been analysed by this attack. In 2008, Wei et al. proposed the first DFA on ARIA-128. Their attack can recover the 128-bit secrey key by about 45 faulty ciphertexts. In this paper, we propose an improved DFA on ARIA-128. We can recover the 12S-bit secret key by only 4 faulty ciphertexts with the computational complexity of O($2^{32}$).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.4
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• pp.1246-1262
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• 2021

Recent studies have demonstrated the strong ability of deep convolutional neural networks (CNNs) to significantly boost the performance in single image super-resolution (SISR). The key concern is how to efficiently recover and utilize diverse information frequencies across multiple network layers, which is crucial to satisfying super-resolution image reconstructions. Hence, previous work made great efforts to potently incorporate hierarchical frequencies through various sophisticated architectures. Nevertheless, economical SISR also requires a capable structure design to balance between restoration accuracy and computational complexity, which is still a challenge for existing techniques. In this paper, we tackle this problem by proposing a competent architecture called Enhanced U-Net Network (EUN), which can yield ready-to-use features in miscellaneous frequencies and combine them comprehensively. In particular, the proposed building block for EUN is enhanced from U-Net, which can extract abundant information via multiple skip concatenations. The network configuration allows the pipeline to propagate information from lower layers to higher ones. Meanwhile, the block itself is committed to growing quite deep in layers, which empowers different types of information to spring from a single block. Furthermore, due to its strong advantage in distilling effective information, promising results are guaranteed with comparatively fewer filters. Comprehensive experiments manifest our model can achieve favorable performance over that of state-of-the-art methods, especially in terms of computational efficiency.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2003.10a
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• pp.229-235
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• 2003

Research of basis technology to construct the human haplotype map is one of active areas in SNP post-genomics research. Identification of haplotype block structure from haplotype data is key step in the haplotype map project. Several algorithms have been proposed for the block identification, including the greedy algorithm, and the dynamic programming based algorithm. This paper analyzed block partitioning method of several algorithm which has been proposed in recent years. HapBlock and HaploBlockFinder are programs used in our experiment.

• Journal of the Korea Computer Industry Society
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• v.10 no.3
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• pp.105-114
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• 2009

In this paper a modified Feistel network 128 bit block cipher algorithm is proposed. The proposed algorithm has a 128, 196 or 256 bit key and it updates a selected 32 bit word from input value whole by deformed Feistel Network structure. Existing of such structural special quality is getting into block cipher algorithms and big distinction. The proposed block cipher algorithm shows much improved software speed compared with international standard block cipher algorithm AES and domestic standard block cipher algorithm SEED and ARIA. It may be utilized much in same field coming smart card that must perform in limited environment if use these special quality.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.75
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• pp.137-158
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• 2017

Traditional banking systems of transactions are being replaced by FfinTech. Block Chain System can be a key point in Fourth Industrial Revolution such as AI, Big Data, IOT and also can be used as a tools of smart contract or smart payment systems in International Trade. If banking regulation is to be liberalized FinTech would be more activated in Korea and various attempts would be available especially smart payment in business. There are so many levels to be achieved from the time of contract to the time of clearance. We cannot expect speed and range of IT advancement and international trade, Block Chain system will challenge the traditional banking process. First, Block Chain Payment system can be used in P2P, B2B transaction and also T/T in small business. Second, Bit Coin transaction can be available within the parties without the Trusted Third Party. Third, By using of Block Chain system Traditional International Trade process can be altered.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.1-10
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• 2006

Rock masses in nature include various rock discontinuities such as faults, joints, bedding planes, fractures, cracks, schistosities, and cleavages. The behavior of rock structures, therefore, is mainly controlled by various rock discontinuities. In many tunnels, enormous cost and time are consumed to cope with the failing or sliding of rock blocks, which cannot be predicted because of the complexity of rock discontinuities. It is difficult to estimate the properties of rock masses before the rock excavation. The observational design and construction method of tunnels in rock masses is becoming important recently. In this paper, a new observational design and construction method for rock block evaluation of tunnels in discontinuous rock masses is proposed, and then applied to the tunnel based on actual rock discontinuity information observed in the field. It is possible to detect key blocks all along the tunnel exactly by using the numerical analysis program developed far the new observational design and construction method. This computer simulation method with user-friendly interfaces can calculate not only the stability of rock blocks but also the design of supplementary supports. The effectiveness of the proposed observational design and construction method has been verified by the confirmation of key block during the enlargement excavation.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.39-48
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• 2003

Previous analytical models for key blocks have been based on the assumption of infinite persistent discontinuities. In this paper, a key block analysis method considering the finite persistence of discontinuities is proposed as a stability evaluation method in tunnel constructions, and then applied to an actual example site. Three-dimensional rock block identification with consideration of the persistence of discontinuities is performed by using discontinuity disk model. The removability and stability analyses of rock blocks formed by the identification method are performed. The identification method can handle convex and concave shape blocks. In order to demonstrate the applicability of this developed numerical method to the stability evaluation in tunnel constructions, the analytical results are examined and compared one another.