• 중국학논총
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• no.63
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• pp.1-28
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• 2019

This study set out to examine the variant forms in the Korean block-printed edition of YouYangZaZu(酉陽雜俎)n terms of modifications of writing forms, increase and decrease of strokes, shortening and lengthening of strokes, connection and interruption of strokes, replacement of Pyeonbang(偏旁), and changing structures and positions. The study also aims to investigate the frequent uses and characteristics of variant forms. The findings show that the variant forms of YouYangZaZu(酉陽雜俎) include characters in some parts. There are 1,500 variant forms in the Korean block-printed edition of YouYangZaZu(酉陽雜俎)ith numerous characters of both various modifications and increasing or decreasing strokes based on the same characters. There are mixed uses of block letters and variant forms throughout the book from a single form to ten different forms of a character.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.85-96
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• 2008

One of the typical methods to prevent tampering and reverse engineering on executable codes is to encrypt them. This paper proposes a code block cipher method based on key chaining to encrypt the code. The block cipher by key chaining has been known to be inadequate for encrypting the code with control transfer, even though the key chaining has advantage of hiding the keys in blocks and making the individual keys different from block to block. This paper proposes a block transformation and duplication method to apply the block cipher by key chaining to the executable codes with control transfer instructions, and shows the idea works with the MIPS instruction set.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.72-76
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• 1996

We propose a novel algorithm for fractal video sequence coding, based on the circular prediction mapping (CPM), in which each range block is approximated by a domain block in the circularly previous frame. In our approach, the size of the domain block is set to be same as that of the range block for exploiting the high temporal correlation between the adjacent frames, while most other fractal coders use the domain block larger than the range block. Therefore the domain-range mapping in the CPM is similar to the block matching algorithm in the motion compensation techniques, and the advantages of this similarity are discussed. Also we show that the CPM can be combined with non-contractive inter-frame mapping (NCIM), improving the performance of the fractal sequence coder further. The computer simulation results on real image sequences demonstrate that the proposed algorithm provides very promising performance at low bit-rate, ranging from 40 Kbps to 250 Kbps.

• Journal of Environmental Impact Assessment
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• v.22 no.1
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• pp.99-107
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• 2013

This study is an impact assessment of building blocks on urban inundation depth and area. LiDAR data is used to generate two original data set in terms of DEM with $5{\times}5$ meter and building block elevation layer of the study drainage area in Cheongju and then the building block elevation layer is modified again to the mesh data with same size to DEM. Two-dimensional inundation analysis is carried out by applying 2D SWMM model. The inundation depth calculated by using the building block elevation layer shows higher reliability than the DEM. This is resulted from the building block interference to surface flow. In addition, the maximum flooded area by DEM is two times wider than the area by building block layer. In the case of the surface velocity, the difference of velocity is negligible in either DEM or building block case in the low building impact zone. However, If the impact of building on the surface velocity was increase, the gap of velocity was significant.

• Asia pacific journal of information systems
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• v.30 no.1
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• pp.21-30
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• 2020

Bitcoin (BTC) is a type of cryptocurrency that supports transaction/payment of virtual money between BTC users without the presence of a central authority or any third party like bank. It uses some cryptographic techniques namely public- and private-keys, digital signature and cryptographic-hash functions, and they are used for making secure transactions and maintaining distributed public ledger called blockchain. In BTC system, each transaction signed by sender is broadcasted over the P2P (Peer-to-Peer) Bitcoin network and a set of such transactions collected over a period is hashed together with the previous block/other values to form a block known as candidate block, where the first block known as genesis-block was created independently. Before a candidate block to be the part of existing blockchain (chaining of blocks), a computation-intensive hard problem needs to be solved. A number of miners try to solve it and a winner earns some BTCs as inspiration. The miners have high computing and hardware resources, and they play key roles in BTC for blockchain formation. This paper mainly analyses the underlying cryptographic techniques, identifies some weaknesses and proposes their enhancements. For these, two modifications of BTC are suggested ― (i) All BTC users must use digital certificates for their authentication and (ii) Winning miner must give signature on the compressed data of a block for authentication of public blocks/blockchain.

• Journal of People, Plants, and Environment
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• v.22 no.6
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• pp.575-582
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• 2019

Moss is used as an important material in indoor landscaping as well as outdoor landscaping. Moss is vivid green during growth and excellent in ornamental value. But when temperature drops, moss stops growth, turns brown or loses its ornamental value. In the present experiment, for the purpose of classifying native mosses according to the growth response to low temperature, the temperature of the plant growth chamber was set to 15℃/5℃ (16h/8h, day/night) and 5℃ (24h) for 8 weeks using nine native moss species. Thereafter, the temperature of the plant growth chamber was set to 20℃, and then the changes of moss block area and moss color were measured. The changes of moss block area and moss color were measured using a Photoshop program, after each moss block was photographed. As a result, Atrichum undulatum (Hedw.). Beauv., Etodon luridus (Griff.) A. Jaeger, Bachythecium plumosum (Hedw.) Schimp, Plagiomnium cuspidatum (Hedw.) T.J. Kop, and Hypnum plumaeforme Wilson showed a small decrease in moss block area at low temperature, and their recovery were the fastest at 20℃. These three species had higher green values at low temperature compared to other species, and the greenness increased rapidly at 20℃. On the other hand, Atrichum undulatum (Hedw.). Beauv., Marchantia polymorpha L., and Thuidium cymbifolium (Mitt.) A. Jaeger showed the smallest block area at low temperature and the lowest recovery even at 20℃. Their green values also decreased significantly at low temperature, and maintained low green value even at 20℃. These results showed that these three moss species are sensitive to low temperature. The remaining Myuroclada maximowiczii, Plagiomnium cuspidatum, and H. erectiusculum showed moderate responses to low temperature compared to other six species of mosses.

• ETRI Journal
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• v.44 no.1
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• pp.38-50
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• 2022

This paper presents a study on the use of encoder-derived features in decoder-side depth estimation. The scheme of multiview video encoding does not require the transmission of depth maps (which carry the geometry of a three-dimensional scene) as only a set of input views and their parameters are compressed and packed into the bitstream, with a set of features that could make it easier to estimate geometry in the decoder. The paper proposes novel recursive block splitting for the feature extraction process and evaluates different scenarios of feature-driven decoder-side depth estimation, performed by assessing their influence on the bitrate of metadata, quality of the reconstructed video, and time of depth estimation. As efficient encoding of multiview sequences became one of the main scopes of the video encoding community, the experimental results are based on the "geometry absent" profile from the incoming MPEG Immersive video standard. The results show that the quality of synthesized views using the proposed recursive block splitting outperforms that of the state-of-the-art approach.

• Journal of The Geomorphological Association of Korea
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• v.26 no.2
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• pp.1-14
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• 2019

This study analyzed the relativity between block stream and talus distributions by employing a likelihood ratio approach. Possible distribution sites for each debris slope landform were extracted by applying a spatial integration model, in which we combined fuzzy set model, Bayesian predictive model, and logistic regression model. Moreover, to verify model performance, a success rate curve was prepared by cross-validation. The results showed that elevation, slope, curvature, topographic wetness index, geology, soil drainage, and soil depth were closely related to the debris slope landform sites. In addition, all spatial integration models displayed an accuracy of over 90%. The accuracy of the distribution potential area map of the block stream was highest in the logistic regression model (93.79%). Eventually, the accuracy of the distribution potential area map of the talus was also highest in the logistic regression model (97.02%). We expect that the present results will provide essential data and propose methodologies to improve the performance of efficient and systematic micro-landform studies. Moreover, our research will potentially help to enhance field research and topographic resource management.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.12
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• pp.1792-1799
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• 1990

Two cases of block coded phase/frequncy modulations are investigated. minimum Euclidean distances are calculated as the function of modulation index h and rotation angle \ulcorner in the cases of 2-FSK/4-PSK and 2-FSK/8-PSK. Method of signal set partitioning is described, especially for the case of 2-FSK/8-PSK. The results are compared with S.I. Sayegh's work and shown better performance. For example, with simple parity check and repetition codes, we can get coding gain of 3 dB in the case of 2-FSK/4-PSK with block length n=4. We get 5.33 dB in the case of 2-FSK/8-PSK with n=4. And it is believed that we can get higher coding gain with proper combinations of block code and n-FSK/m-PSK type channel signal constellations.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.329-330
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• 2006

This paper presents a recovery technique for images with block-based corruption by transmission losses. Conventional methods that do not consider edge directions can cause blocked blurring artifacts. In this paper, we present a block recovery scheme using Haar wavelet features. The adaptive selection of neighboring blocks is performed based on the energy ratio f wavelet subbands. The lost blocks are recovered by linear interpolation in the spatial domain using selected block pairs. The proposed directional recovery method is effective for the strong edge because it exploits the varying neighboring blocks adaptively according to the edges and the directional information in the image. The proposed method outperforms the previous methods that used only a predefined set of neighboring blocks.