• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.499-502
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• 2001

Fractal image coding suffers from the long search time of domain pool although it provides many properties including the high compression ratio. We find that the normalized variance of a block is independent of contrast, brightness. Using this observation, we introduce a self similar block searching method employing the d-dimensional nearest neighbor searching. This method takes Ο(log/N) time for searching the self similar domain blocks for each range block where N is the number of domain blocks. PSNR (Peak Signal Noise Ratio) of this method is similar to that of the full search method that requires Ο(N) time for each range block. Moreover, the image quality of this method is independent of the number of edges in the image.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.77-85
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• 2006

There is the spatial correlation of the video sequence between the motion vector of current blocks. In this paper, we propose the enhanced fast block matching algorithm using the spatial correlation of the video sequence and the center-biased properly of motion vectors. The proposed algorithm determines an exact motion vector using the predicted motion vector from the adjacent macro blocks of the current frame and the Cross-Hexagonal search pattern. From the of experimental results, we can see that our proposed algorithm outperforms both the prediction search algorithm (NNS) and the fast block matching algorithm (CHS) in terms of the search speed and the coded video's quality. Using our algorithm, we can improve the search speed by up to $0.1{\sim}38%$ and also diminish the PSNR (Peak Signal Noise Ratio) by at nst $0.05{\sim}2.5dB$, thereby improving the video qualify.

• Journal of the Korea Institute of Building Construction
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• v.19 no.4
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• pp.307-312
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• 2019

Sludge generated in the production of ready-mixed concrete is classified as waste and processed at a high cost. In particular, small and medium-sized ready-mix manufacturer are burdened with such costs, and some companies are illegally processing them. Therefore, the purpose of this study is to suggest a method for recycled remicon sludge as a concrete block composition. When the remicon sludge is simply dried, the residual chemical admixture and ettringitee contained in the sludge are present, so that the compressive strength of the concrete block and the compressive strength after freezing and thawing are largely deteriorated to meet the quality standards of the concrete shore and retaining wall block It was not possible to do. As a method for satisfying the physical performance, it was found that the remicon sludge was calcined at a high temperature of about $900^{\circ}C$. to decompose ettringite and residual chemical admixture and then used it.

• The Korean Journal of Pain
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• v.35 no.2
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• pp.202-208
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• 2022

Background: Neurolytic celiac plexus block (NCPB) is a typical treatment for severe epigastric cancer pain, but the therapeutic effect is often affected by the variation of local anatomical structures induced by the tumor. Greater and lesser splanchnic nerve neurolysis (SNN) had similar effects to the NCPB, and was recently performed with a paravertebral approach under the image guidance, or with the transdiscal approach under the guidance of computed tomography. This study observed the feasibility and safety of SNN via a transdiscal approach under fluoroscopic guidance. Methods: The follow-up records of 34 patients with epigastric cancer pain who underwent the splanchnic nerve block via the T11-12 transdiscal approach under fluoroscopic guidance were investigated retrospectively. The numerical rating scale (NRS), the patient satisfaction scale (PSS) and quality of life (QOL) of the patient, the dose of morphine consumed, and the occurrence and severity of adverse events were recorded preoperatively and 1 day, 1 week, 1 month, and 2 months after surgery. Results: Compared with the preoperative scores, the NRS scores and daily morphine consumption decreased and the QOL and PSS scores increased at each postoperative time point (P < 0.001). No patients experienced serious complications. Conclusions: SNN via the transdiscal approach under flouroscopic guidance was an effective, safe, and easy operation for epigastric cancer pain, with fewer complications.

• Journal of the Korean Geotechnical Society
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• v.23 no.12
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• pp.95-107
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• 2007

This study describes compressive characteristics of marine clay at southwestern coast in Korea by large block and piston samples. Through the analysis of disturbance effect and various consolidation test, consolidation result shows that volumetric strain from large block samples is lower than piston samples and compression index of large block samples is larger than piston samples value. We suggest new empirical equation of compression index by the effect of compression index following sampling method. If consolidation settlement is presumed using empirical equation of compression index, the resort will be more reasonable in predicting settlement than that obtained by the decision of compressibility characteristics from piston samples.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.12
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• pp.1825-1836
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• 2008

Many applications in computer graphics require complex and highly detailed models. However it is often desirable to use approximations in place of excessively detailed models in order to control the processing time. Thus, we aim to develop a notion of optimal matrix to simplify surface which can rapidly obtain the high quality 2D patterns flattening 3D surface as follows. Firstly, two 3D bodies are modeled based on existing Size Korea data. Secondly, each model is divided by shell and block for its pattern draft. Thirdly, each block is flattened by grid and bridge method. Finally, we selected the optimal matrix and demonstrated the efficiency and quality of the proposed method. This proposed approach accommodates surfaces with darts, which are commonly used in the clothing industry to reduce the deformation of surface forming and flattening. The resulting optimal matrix could be an initiation of standardization for pattern flattening. It is expected that this method could facilitate much better approximation in both efficiency and precision.

• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.703-712
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• 2019

Single image Super-Resolution (SISR) aims to generate a visually pleasing high-resolution image from its degraded low-resolution measurement. In recent years, deep learning - based super - resolution methods have been actively researched and have shown more reliable and high performance. A typical method is WaveletSRNet, which restores high-resolution images through wavelet coefficient learning based on feature maps of images. However, there are two disadvantages in WaveletSRNet. One is a big processing time due to the complexity of the algorithm. The other is not to utilize feature maps efficiently when extracting input image's features. To improve this problems, we propose an efficient single image super resolution method, named RDB-WaveletSRNet. The proposed method uses the residual dense block to effectively extract low-resolution feature maps to improve single image super-resolution performance. We also adjust appropriated growth rates to solve complex computational problems. In addition, wavelet packet decomposition is used to obtain the wavelet coefficients according to the possibility of large scale ratio. In the experimental result on various images, we have proven that the proposed method has faster processing time and better image quality than the conventional methods. Experimental results have shown that the proposed method has better image quality by increasing 0.1813dB of PSNR and 1.17 times faster than the conventional method.

• ETRI Journal
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• v.36 no.5
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• pp.752-760
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• 2014

This paper proposes a conditional replenishment algorithm (CRA) to improve the visual quality (where spatial resolutions of the left and right views are mismatched) of a hybrid stereoscopic 3DTV that is based on the ATSC-M/H standard. So as to generate an enhanced view, the CRA is to choose the better substitute among a disparity-compensated view with high quality and a simply interpolated view. The CRA generates a disparity map that includes modes and disparity vectors as additional information. It also employs a quad-tree structure with variable block size by considering the spatial correlation of disparity vectors. In addition, it takes advantage of the disparity map used in a previous frame to keep the amount of additional information as small as possible. The simulation results show that the proposed CRA can successfully improve the peak signal-to-noise ratio of a poor-quality view and consequently have a positive effect on the subjective quality of the resulting 3D view.

• Journal of Broadcast Engineering
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• v.24 no.3
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• pp.420-429
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• 2019

Recently, researches using Convolutional Neural Network (CNN)-based approaches have been actively conducted to improve the reduced quality of compressed video using block-based video coding standards such as H.265/HEVC. This paper aims to summarize and analyze the network models in these quality enhancement studies. At first the detailed components of CNN for quality enhancement are overviewed and then we summarize prior studies in the image domain. Next, related studies are summarized in three aspects of network structure, dataset, and training methods, and present representative models implementation and experimental results for performance comparison.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.2
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• pp.29-40
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• 2007

The purpose of this research is to propose a method for scoring the quality of a fingerprint image using the local information derived from the fingerprint image. In previous works for the quality measuring, most of the quality scores are related to the performance of a matching algorithm, and this makes the quality result more subjective. The quality score of a fingerprint image proposed in this work is sensor-independent, source-independent and matcher-independent one, and this concept of fingerprint sample quality results in effective improvement of the system performance. In this research, a new definition of fingerprint image quality and a new method for measuring the quality are proposed. For the experiments, several sub-databases from FVCs are used and the proposed method showed reasonable results for the test database. The proposed method can be used in various systems for the numerous purposes since the quality scores generated by the proposed method are based on the idea that the quality of fingerprint should be sensor-independent, source-independent and matcher-independent.