• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.41-49
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• 2009

Poor compaction of subgrade soil causes low stiffness and bearing capacity of sublayers so that faulting and differential settlements can be generated between new and old pavement surfaces in case of widening works. However, investigation of verifying the reason of producing the defects in the pavements are not performed in detail. In this study, several in-field tests including PMT and PBT were performed for obtaining stiffness of the sublayers in new and old pavements respectively of an widening project. Then, based on the obtained stiffness values and the measured deformations obtained by specially designed tilt meters, the main reasons of generating different deformations between the old and new pavement sections and the relationship between the deformation and stiffness are verified.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11b
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• pp.561-564
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• 2003

일반적으로 피부 미용분야에서 건강모발과 손상모발을 구분하기 위해 전자현미경으로 촬영된 영상에서 모발의 벌어짐, 갈라짐, 젖혀짐, 탈락, 용해 등의 특징을 관찰하여 사용하고 있다. 그러나 주관적이고 정성적인 판단에 의존하기 때문에 수치적인 기준을 적용하는 객관성이 있는 판단이 요구된다. 본 논문에서는 영상처리 분야에서 에지 특성이 영상 분류나 검색에 사용되는 점을 활용, 에지처리된 영상의 구간별 밝기 누적정보를 비교하여 건강모발과 손상모발의 구분이 가능함을 보인다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1992.06a
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• pp.60-65
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• 1992

액정은 합성에 의해서 만들어지는 고분자 화합물로서 액체와 고체결정의 중간적인 특성을 갖는 물질이다. 따라서 액체와 같이 점도를 갖고 유동하며 고체와 같이 외부하중에 대하여는 탄성변형을 하므로 일반 윤활유보다 월등한 윤활특성이 기대된다. 액정은 분자배열에 따라 smectics, cholesterics, Nematics의 세종류로 나뉘어지며 Smectics는 다시 Smectic A, Smectic C등으로 분류되며 관심대상은 Smectic A이다. 본 연구에서는 평판 슬라이더 베어링의 간극에 액정층이 형성되어있을때 액정의 탄성계수, 침투계수 및 벌어짐계수가 베어링부하, 액정층의 유동현상등에 미치는 영향을 비선형 유한 요소법을 사용하여 해석하고 레이놀즈 이론해와 비교하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.361-370
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• 2003

In this study, the performance of water tightness of water expansional sealing material and gasket was evaluated. The water tightness test was performed varying the type of inner pressure condition, for which the water expansional sealing material was inundated for 5 days to evaluate the ability of water tightness. In order to carry out this test, we made use of two types of water expansional sealing material; general type and combined type with non-expansional rubber. In the case of gasket, EPDM gasket and complex gasket sticked to the water expansional sealing material were applied. The performance of water tightness depended on the construction defect and the deformation of segment. The construction defect and segment deformation were generally expressed by gap and offset of the construction joint. The results, of tests showed that the performance of water tightness was largely influenced by the gap between segments. Management criteria of gap and offset were proposed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.303-306
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• 2002

변위가 발생한 해안도로 옹벽에 대한 원인을 규명하기 위하여 기반암과 매립부 지반에 대한 조사를 실시하였다. 연구지역에서 지질구조선의 발달은 관찰되지 않고 지표에서 기반암의 거동은 낙석의 형태로 나타난다. 기반암은 생교란작용의 유무에 따라 상, 하부지층이 구분되며 하부 지층은 신선한 상태로 이완된 불연속면은 나타나지 않는다. 변위는 옹벽의 이음부에 집중되며 옹벽의 운동방향은 우향이동과 좌향이동이 반복되며 최초 변위 발생지점 (시 점부)에서 멀어짐에 따라 장력에 의한 확장 (벌어짐)이 우세하며 종점부에서 회전운동이 수반된다. 이음부의 확장과 회전은 최초 발생 지점에서 응력이 전달되는 과정에서 나타난 것으로 해석된다. 매립부 지반의 전기비저항탐사에서 상부의 매립층은 높은 전기비저항을 가지는 것에 반해 하부는 매우 낮은 전기비저항 값을 보여준다. 이는 매립부의 하부지반이 해수면 이하에 위치하여 해수와 같은 유체의 영향을 받으나, 상부는 유체의 영향을 거의 받지 않는 것으로 추정된다. 반면 최초 변위가 발생한 지점의 매립부 지반은 하부와 같이 낮은 전기비저항 값을 보여준다. GPR 탐사에서 최초 변위 발생 지점에서 매질의 이완 내지 공동으로 추정되는 구조가 관찰된다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.537-544
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• 2021

In order to describe the fill-up stages of a near-surface disposal facility vault, a mock-up test is performed, and its behavior during the fil l -up stages is investigated. On an in-site concrete foundation with a l ength of 6600mm, a width of 6600mm and a thickness of 400mm, a reinforced concrete disposal vaul t is manufactured with 4 precast (PC) corner wal l s and 8 PC side wal l s. 36 wasted drums are pl aced on the 1st fl oor in 6 by 6, and then the empty space is fil l ed with grout fil l er. These processes are repeated up to the 5th floor, and the verticality and the joint gaps are measured for each fill-up stage. The verticality is measured using a level at 6 positions on each side wall (3 positions on the left and right sides, respectivel y), i.e. a total of 24 positions on the 4 side wal l s. The joint gaps are measured at 9 positions on each side wal l (3 positions on the left, center and right sides, respectively), I.e. a total 36 positions on the 4 side walls. To measure the joint gaps, crack tips are installed on the left and right sides of every joint gap, and vernier calipers are used. The measured verticality obtained through the mock-up test was found to be ±0.1° based on the initial stage (ST0), and the result of the joint gap was up to 0.38mm. This appears to have a negligible effect on the structure.

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.111-121
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• 2010

As the customer's interest for sidewalk block in the street or apartment complex is increasing, the materials of block which had been a concrete block exclusively are varied to clay paver, native rock and wood etc. Especially, the sales volume of clay paver which is environment-friendly and ergonomic is dramatically increasing every year with two digits growth rate, however, many problems like "Edge Cracking" "Freezing Breakage" "Bending Breakage" "Joint Gap" are happening frequently within a couple of hours after installation due to the durabilities. Because of the characteristics of Ceramic products, clay pavers are very easy to be broken when they are bumped against each other. In addition, they are relatively fragile by a freezing expansion breakage when exposed to water due to hydrophilic property as well as the intensity and absorptance of the products are varied with small difference from the production process such as production equipment and process control. Therefore, it costs a lot of money to repair the breakdown unless production and installation is carried out according to the strict criteria of the quality control. In this study, the symptoms of breakdown frequently happened in clay paver are classified by each type and finally the solution for this problem in the production of brick, installation and criteria of quality control through compressive strength and absorptance test is suggested.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.251-253
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• 2010

In the leakage test of a Main Oxidizer shut-off valve, gas leakage was found on the middle flange with a metal conical seal. The structural analysis was performed for three models with different numbers of bolts and flange shapes and then one model was selected in consideration of the minimum axial gap deformation as well as the weight increment due to the change of flange shapes. Experimental leakage tests for the simulated flanges of the selected model has resulted in no gas leakage, and consequently the structural analysis method for the design of the middle flanges has proved feasible.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.4
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• pp.71-76
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• 2024

In this paper, we propose a platform for learning deboning technology of Korean beef through vr-based experiential learning. The Korean beef deboning process is not only a food ingredient that has represented Korea for a long time, but also an object with high traditional cultural value. However, due to the hard and dangerous work envrionment of the deboning field, the number of skilled dobiners is gradually decreasing. This study proposes a platform that can train these deboning technicians in virtual reality and covers applied technologies used. In particular, we discussed how processes such as bending, opening, and cutting are implemented during meat cutting, which is a very important part of deboning work. In the experiment, cutting work was performed based on actual meat modeling, and complete cutting was tested.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.893-899
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• 2015

In the design of injection molds, the temperature distribution and deformation of the mold is one of the most important parameters that affect the flow characteristics, flash generation, and surface appearance, etc. Plastic injection analyses have been carried out to predict the temperature distribution of the mold and the pressure distribution on the cavity surface. As the input loads, we transfer the temperature and pressure results to the structural analysis. We compare the structural analysis results with the thermal expansion effect using the actual flash and step size of a smartphone cover part. To reduce the flash problem, we proposed a new mold design, and verified the results by performing simulations.