• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.429-436
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• 2005

In this study, we have compared with the differences between the extent of sampling disturbance and consolidation characteristics by experiments, which are consolidation test and have been performed with Kwang-Yang clay samples. The effects on sampling disturbance to consolidation characteristics of soft clay have been inverstigated by using soil samples obtained from large block sampling and piston sampling methods. Through a few experiments, we've got important results which are that the consoilidation parameter of large block sample(Pc, Cc, Cv) is much larger than the value of parameter of piston sample. We've also found the fact that the large block sample using the large size sampler is much better than piston sample in the quality of goods to lessen the effects on disturbance of sampling. When compared to the parameter of consolidation along with the methods of experiment, we found that the result performed by large size consolidation test is the greatest one and CRS is much better than standard consolidation test to seek for proper parameter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1361-1369
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• 1996

Motion estimation is one of the key components for high quality video coding. In this paper, a new motion estimation scheme for MPEG-like video coder is suggested. The proposed temporally adaptive motion estimation scheme consists of five functional blocks: Temporal subband analysis (TSBA), extraction of temporal information, scene change detection (SCD), picture type replacement (PTR), and temporally adapted block matching algorithm (TABMA). Here all the functional components are based on the temporal subband analysis. In this papre, we applied the analysis part of subband decompostion to the temporal axis of moving picture sequence, newly defined the temporal activity distribution (TAD) and average TAD, and proposed the temporally adapted block matching algorithm, the scene change detection algorithm and picture type replacement algorithm which employed the results of the temporal subband analysis. A new block matching algorithm TABMA is capable of controlling the block matching area. According to the temporal activity distribution of objects, it allocates the search areas nonuniformly. The proposed SCD and PTR can prevent unavailable motion prediction for abrupt scene changes. Computer simulation results show that the proposed motion estimation scheme improve the quality of reconstructed sequence and reduces the number of block matching trials to 40% of the numbers of trials in conventional methods. The TSBA based scene change detection algorithm can detect the abruptly changed scenes in the intentionally combined sequence of this experiment without additional computations.

• Journal of Korea Multimedia Society
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• v.5 no.1
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• pp.28-37
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• 2002

In this paper, we propose new methods used in MPEG codec that can improve the picture quality degradations of the reconstructed images, such as blocking artifacts, without additional computations. At first, a new 2-step MAD motion search is presented in the motion search and compensation course to reduce the computations and the errors of block boundary pixels. And we also present an overlapped 2-step MAD motion search that use the pixels beyond the block boundary using the reduced computations. In DCT/quantization course for intra-blocks, 1-D DCT predictive quantization and pixel difference predictive quantization, those use the adjacent pixel sets of the Previously reconstructed blocks and improve the inter-block continuity, are presented. As simulation results, proposed methods shows better picture qualities by reducing blocking artifacts than that of the conventional MPEG.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.1
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• pp.1-12
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• 2019

This paper proposes a new motion vector smoothing and motion compensation method to increase the frame rate of videos. The proposed method reduces false motion vector smoothing by improving the weight with reflecting accuracy to overcome the limitation of the conventional motion vector smoothing using the adaptively weighted vector median. Also, to improve the interpolated image quality of the conventional OBMC(Overlapped Block Motion Compensation), a scheme that divides an original block into 4 sub-blocks and then generates the interpolated frame using the reestimated motion vector for each sub-block is proposed. The simulation results prove that the proposed method can provide much better objective and subjective image quality than the conventional method.

• Journal of the Korean Geosynthetics Society
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• v.4 no.4
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• pp.47-56
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• 2005

With the need of efficient site use retaining walls have frequently used. Of them dry cast modular block wall(MBW), in which geogrid and concrete block are used is getting popular because of its simplicity and economical efficiency of construction. However, since this method is based on the theory of earth pressure, sands with good quality should be used. In contrast, reinforced soil slope(RSS) that the slope is less than $70^{\circ}$ can use wider range of soil than MBW. A hybrid reinforced geo-structure might be a good alternative in view of overcoming difficulty obtaining soils with good quality as well as maximizing the efficiency of site use. This method is composed of reinforced block wall and reinforced soil slope. In this method, reinforced block wall is constructed up to a certain height vertically at ground boundary first. Reinforced soil slope is then constructed on the block wall subsequently. This paper introduces several technical points that should be taken into account in design and construction.

• Journal of KIISE:Software and Applications
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• v.32 no.10
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• pp.949-955
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• 2005

In this Paper, we propose fast block matching algorithm by dividing complex areas based on complexity order of reference block and square sub-block to reduce an amount of computation of full starch(FS) algorithm for fast motion estimation, while keeping the same prediction quality compared with the full search algorithm. By using the fact that matching error is proportional to the gradient of reference block, we reduced unnecessary computations with square sub-block adaptive matching scan based image complexity instead of conventional sequential matching scan and row/column based matching scan. Our algorithm reduces about $30\%$ of computations for block matching error compared with the conventional partial distortion elimination(PDE) algorithm without any prediction quality, and our algorithm will be useful in real-time video coding applications using MPEG-4 AVC or MPEG-2.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7C
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• pp.628-633
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• 2010

This paper proposes a block matching algorithm to improve the sub-block matching algorithm that uses partial sub-blocks being a great contribution to the block matching. Unlike the conventional algorithm using the one sub-block group the proposed algorithm uses two sub-block groups. The matching using the small group selects a candidate block to be a good possibility of a similar block with a small computation cost and the additional matching using the large group in the selected block decreases a wrong matching. Simulation results show that the proposed algorithm always has good image quality at the same computation cost as compared to the conventional algorithm and it has an outstanding performance at the matching using a few sub-blocks.

• Journal of Korean Society for Quality Management
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• v.19 no.1
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• pp.16-27
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• 1991

Propose three rank tests based on different kinds of ranking methods for comparing several treatments with a control in a randomized block experiment. Monte Carlo power simulation study is examined in some small sample sizes and configurations to recommend a better test for applications.

• Smart Media Journal
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• v.6 no.2
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• pp.9-14
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• 2017

A packet loss in wireless environments causes a severe degradation of video quality in video communications. In this paper, a novel video error concealment algorithm is presented by combining boundary errors and a block reliability measure. The block reliability measure decides the reliability of a block by checking residual errors of a block. In the proposed approach, a motion vector of a missing unreliable block in an inter coded frame is obtained initially based on the motion vector of the same block in the reference frame. Furthermore, if the block in the reference frame is unreliable according to the reliability measure, a new motion vector is decided based on block boundary errors around the initial motion vector. According to our simulations, the proposed approach shows promising results for error concealment in error-prone wireless environments.

• Resources Recycling
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• v.31 no.5
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• pp.42-51
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• 2022

Aggregate resources in Korea are expected to run out owing to an increase in development demand and construction investment. Recycled concrete aggregates (RCA), extracted from waste concrete, have a lower quality than natural aggregates. However, RCA can produce concrete similar in quality to the normal concrete by aggregate pretreatment, use of admixtures, and quality control. RCA are most suitable for use in precast concrete products such as sidewalk blocks and revetment blocks. Herein, the feasibility of producing revetment blocks using recycled aggregate concrete (RAC), similar in quality to normal concrete, was analyzed. The amount of RCA was varied, and moderate high early strength cement and steam curing were used to produce the concrete test blocks. In the block test, the load resistance characteristics of the blocks were evaluated to determine optimal RAC and glass fiber reinforced polymer (GFRP) rebar compositions. Thus, the variable that reduced the cement content was determined at the same level as that of natural aggregate concrete by the control of steam curing. In the concrete block test, although this depends on the reinforcement ratio, the RAC block exhibited the same or better performance than a normal concrete block. Therefore, the low quality of RCA in RAC is no longer a problem when concrete mixing and curing are controlled and appropriate reinforcement is used.