• International Journal of Highway Engineering
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• v.7 no.2 s.24
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• pp.87-95
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• 2005

To prevent the lowering of structural capability due to freezing and thawing in cold winter, numerous researches on frost heaving have been performed. As the result, the freezing index contour map of the Korea peninsula has been made for the design of the anti-freezing layer of pavements. However, the validity of the anti-freezing layer needs to be evaluated because systematic investigations on the variation of freezing depth with the thickness and material types of pavement layers and the configuration of the ground have been rarely performed. The freezing index of the Korea Highway Corporation test road site was calculated and the freezing depths of the concrete and asphalt pavements of the test road were investigated using the ambient and pavement temperature and water content. In addition, the investigated freezing depths were compared to the values estimated by existing freezing depth models. This is the preliminary study on the freezing-related data measured at the test road. The results with higher reliability will be produced by the long-term accumulation of the data and the analysis on it.

• Corrosion Science and Technology
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• v.15 no.2
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• pp.84-91
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• 2016

The transport and deposition of corrosion products in pressurized water nuclear reactor (PWR) steam generators have led to corrosion (SCC, denting etc.) problems. Lancing, mechanical cleaning and chemical cleaning have been used to reduce these problems. The methods of lancing and mechanical cleaning have limitations in removing corrosion products due to the structure of steam generator tubes. But high temperature chemical cleaning (HTCC) with EDTA is the most effective method to remove corrosion products regardless of the structure. However, EDTA in chemical cleaning aqueous solution and chemical cleaning environments affects the integrity of materials used in steam generators. The nuclear power plants have to perform the pre-test (also called as qualification test (QT)) that confirms the effect on the integrity of materials after HTCC. This is one of the series studies that assess the effect, and this study determines the effects of 20 % EDTA aqueous solution on defective tubes in high temperature chemical cleaning environments. The depth and magnitude of defects in steam generator (SG) tubes were measured by eddy current test (ECT) signals. Surface analysis and magnitude of defects were performed by using SEM/EDS. Corrosion rate was assessed by weight loss of specimens. The ECT signals (potential and depth %) of defective tubes increased marginally. But the lengths of defects, oxides on the surface and weights of specimens did not change. The average corrosion rate of standard corrosion specimens was negligible. But the surfaces on specimens showed traces of etching. The depth of etching showed a range on the nanometer. After comprehensive evaluation of all the results, it is concluded that 20 % EDTA aqueous solution in high temperature chemical cleaning environments does not have a negative effect on defective tubes.

• Solar Energy
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• v.7 no.2
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• pp.22-29
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• 1987

This paper dealed with thickness variation of bottom heat sotrage zone due to salinity and flow rate of extration hot brine in small test solar pond (0.5m wide, 0.5m high, 1.0m long). Testing apparatus and situation were follows: 7.1 cm of height of suction diffuser and 1.8cm of height of discharge diffuser above the test pond respectively, 0.3cm of slot size of suction diffuser, 1.0cm of slot size of discharge diffuser, 47cm of length of the slot; heating of hot water ($75^{\circ}C$) through separated hot water tank, discharge of the brine into storage zone through discharge diffuser, the extration of the brine through suction diffuser, circulation of the extracted brine through a heat exchanger (cooler). Following results were obtained through the experiments. 1. In small test solar pond, the typical three zone which showed up in real solar pond were established. 2. Richardson Number was used more effectively to confirm hydrodynamic stability of the stratified flow. 3. The thickness of non convective layer had a great effect on the heat storage of the bottom convective layer, then the temperature of bottom convective layer had a relation to that of upper convective layer. 4. Optimum operating condition in the test pond was on 10%-15% of salt concentration and $0.05m^3/hr$ of flow rate of extraction hot brine. 5. Following thickness of 3 zones were available to obtain under optimum operation condition: o bottom storage zone: $30%{\pm}10%$ of total pond depth o non-convective zone: $40%{\pm}10%$ of total pond depth o Upper surface zone: $20%{\pm}10%$ of total pond depth.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.5-15
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• 2004

It is worthwhile to verify the vertical stress distribution in soil mass for rigorous design of foundation. A series of laboratory model tests were performed to investigate the Boussinesq's theory on vertical stress increment in sandy soil mass caused by surface loading. The test results were also compared with Boussinesq's theoretical values. The Boussinesq's theoretical values were always smaller than test results under the footing regardless of depth. Outside of the footing the values were larger than the measured stress at the depth of just footing width. The theory and the test showed similar results when the depth reached two and three times the footing width. The vertical stress decreased as the applied load increased. These trends were confirmed to be valid for the considered range of the relative density of sand and/or the width of footing. More accurate values can be acquired by correcting the theoretical values using these results when Boussinesq's theory is used.

• Journal of the Korean Geotechnical Society
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• v.35 no.2
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• pp.5-17
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• 2019

Dynamic centrifuge model test was conducted to evaluate the dynamic stability of the pile-supported slab track method during dynamic railway loading and earthquake loading. The centrifuge tests were carried out for various condition of embankment height and soft ground depth. Based on test results, we found that the bending moment was increased with embankment height and decreased with soft ground depth. In addition, it was confirmed that the pile-supported slab track system could have dynamic stability for short-period seismic loading. However, in case of long-period seismic loading, such as Hachinohe earthquake, the observed maximum bending moment reached to pile cracking moment at the return period of 2,400 year earthquake. The criterion of ratio between embankment height and soft ground depth was suggested for dynamic stability of pile-supported slab track system.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.761-772
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• 2023

The fire resistance design of timber structures involves calculating the residual section based on charring depth, which is then utilized in structural design. Charring depth is determined from fire-resistance test results in Korea, which currently do not account for the charring properties of the adhesive used in Glued Laminated Timber(GLT) production. This study fabricated GLT using various adhesives employed in domestic GLT production, comparing the charring properties by adhesive type and the fire resistance performance relative to the directionality of the laminated surface. Melamine demonstrated the most advantageous fire resistance performance, followed by resorcinol and polyurethane. Furthermore, it was established that the laminated section exhibited a higher charring rate, influenced by the adhesive, compared to the laminated surface, which significantly impacts the fire resistance performance.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.403-406
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• 2005

This paper deals with the propriety of the shear test data with stirrup reported in ACI and ASCE structural journal and the shear resistance characteristics affected by compressive strength of concrere($f_{ck}$), shear span-to-depth ratio (a/d), tensile reinforcement ratio($\rho$), and shear reinforcement ratio($rho_{v}$). The analysis was accomplished by the 242 shear test data. The test data include the flexural failure data around 40$\%$.

• Journal of Broadcast Engineering
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• v.22 no.4
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• pp.429-437
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• 2017

2D-to-3D conversion technology has been studied over past decades and integrated to commercial 3D displays and 3DTVs. Generally, depth cues extracted from a static image is used for generating a depth map followed by DIBR (Depth Image Based Rendering) for producing a stereoscopic image. Further, motion is also an important cue for depth estimation and is estimated by block-based motion estimation, optical flow and so forth. This papers proposes a new method for motion depth generation using Motion History Image (MHI) and evaluates the feasiblity of the MHI utilization. In the experiments, the proposed method was performed on eight video clips with a variety of motion classes. From a qualitative test on motion depth maps as well as the comparison of the processing time, we validated the feasibility of the proposed method.

• Journal of Broadcast Engineering
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• v.16 no.6
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• pp.916-926
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• 2011

It is well known that high-resolution 3D movie contents frequently do not deliver the identical 3D perception to low-resolution 3D images. For solving this problem, we propose a novel method that produces a new stereoscopic image based on depth map transformation using the spatial complexity of an image. After analyzing the depth map histogram, the depth map is decomposed into multiple depth planes that are transformed based upon the spatial complexity. The transformed depth planes are composited into a new depth map. Experimental results demonstrate that the lower the spatial complexity is, the higher the perceived video quality and depth perception are. As well, visual fatigue test showed that the stereoscopic images deliver less visual fatigue.

• Science of Emotion and Sensibility
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• v.15 no.4
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• pp.477-488
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• 2012

The effort of implementing realistic 3-D depth on 2-D images has been continued persistently with a theoretical understanding of depth perception and its related technical development. The present article briefly reviews a number of popular stereoscopes for studying stereoscopic depth perception according to their implementation principles, and introduces a behavioral experiment as a technical example in which the active-shutter glasses were used. In the present study, participants were tested for their visual memory against perceived depth among a set of items. The depth of the memory and test items was manipulated to be 1) monocular, 2) binocular, or 3) both-monocular-and-binocular respectively. The memory performance was worst in the binocular-depth condition, and best however in the both-monocular-and-binocular condition. These results indicate that visual memory may benefit more from monocular depth than stereoscopic depth, and further suggest that the storage of depth information into visual memory would require both binocular and monocular information for its optimal memory performance.