• Title/Summary/Keyword: 외관성능

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Variation of Material Properties of Fire-killed Timber - Impact of Time on Degradation of Mechanical Properties - (산불 피해목의 재질변화에 관한 연구(II) - 산불 피해 소나무의 경시적 재질변화 -)

  • Park, Jung-Hwan;Park, Byung-Soo;Kim, Kwang-Mo;Lee, Do-Sik
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.1
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    • pp.30-35
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    • 2008
  • Degradation of mechanical properties of fire-killed Korean red pine has been investigated after death in 5 years period. Impact bending absorbed energy was the most sensitive property by elapsed time after forest fire. It is an indication of incipient decay of the wood and can be useful indicator to monitor any change of mechanical property of fire-killed tree after death. Degradation of mechanical properties was more pronounced in sapwood than heartwood. Impact bending absorbed energy was more reduced than any other properties in both sapwood and heartwood, while compressive strength was least impacted by elapsed time after forest fire. It is recommended that the fire-killed Korean red pine can be harvested in one year after the fire for industrial uses by considering decay and consequent changes of mechanical properties.

Weathering Performance Evaluation of Duplex Coating Systems of Thermal Spraying and Painting using Corrosion Test (부식실험에 의한 금속용사와 도장의 복합피복방식법의 내후성능평가)

  • Kim, In Tae;Kim, Ho Seob;Kien, Dao Duy;Jun, Je Hyeong;Ahn, Jin Hee
    • Journal of Korean Society of Steel Construction
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    • v.28 no.2
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    • pp.97-108
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    • 2016
  • Thermally sprayed metals or organic coatings is often used in corrosion protection of steel structures. Duplex coating systems of thermally sprayed metal in combination with organic coating are selected as a new generic type of coatings on steel structures under the highly corrosive environments. In this study, three types of corrosion tests were carried out on four types of thermal sprayed specimens with sealing: zinc, zinc-15%aluminum alloy, aluminum and aluminum-5%magnesium alloy, four types of duplex coated specimens; thermally sprayed metals in combination with paint of acrylic urethane, and painted specimens. NORSOK M-501, Wet/dry cyclic seawater tests and outdoor exposure tests of nine types of specimens were conducted. From the corrosion test results, weathering performance of them were presented.

Deep Learning-based Pixel-level Concrete Wall Crack Detection Method (딥러닝 기반 픽셀 단위 콘크리트 벽체 균열 검출 방법)

  • Kang, Kyung-Su;Ryu, Han-Guk
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.2
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    • pp.197-207
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    • 2023
  • Concrete is a widely used material due to its excellent compressive strength and durability. However, depending on the surrounding environment and the characteristics of the materials used in the construction, various defects may occur, such as cracks on the surface and subsidence of the structure. The detects on the surface of the concrete structure occur after completion or over time. Neglecting these cracks may lead to severe structural damage, necessitating regular safety inspections. Traditional visual inspections of concrete walls are labor-intensive and expensive. This research presents a deep learning-based semantic segmentation model designed to detect cracks in concrete walls. The model addresses surface defects that arise from aging, and an image augmentation technique is employed to enhance feature extraction and generalization performance. A dataset for semantic segmentation was created by combining publicly available and self-generated datasets, and notable semantic segmentation models were evaluated and tested. The model, specifically trained for concrete wall fracture detection, achieved an extraction performance of 81.4%. Moreover, a 3% performance improvement was observed when applying the developed augmentation technique.

Deep Learning-based Rail Surface Damage Evaluation (딥러닝 기반의 레일표면손상 평가)

  • Jung-Youl Choi;Jae-Min Han;Jung-Ho Kim
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.2
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    • pp.505-510
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    • 2024
  • Since rolling contact fatigue cracks can always occur on the rail surface, which is the contact surface between wheels and rails, railway rails require thorough inspection and diagnosis to thoroughly inspect the condition of the cracks and prevent breakage. Recent detailed guidelines on the performance evaluation of track facilities present the requirements for methods and procedures for track performance evaluation. However, diagnosing and grading rail surface damage mainly relies on external inspection (visual inspection), which inevitably relies on qualitative evaluation based on the subjective judgment of the inspector. Therefore, in this study, we conducted a deep learning model study for rail surface defect detection using Fast R-CNN. After building a dataset of rail surface defect images, the model was tested. The performance evaluation results of the deep learning model showed that mAP was 94.9%. Because Fast R-CNN has a high crack detection effect, it is believed that using this model can efficiently identify rail surface defects.

Development of Diagnosis Application for Rail Surface Damage using Image Analysis Techniques (이미지 분석기법을 이용한 레일표면손상 진단애플리케이션 개발)

  • Jung-Youl Choi;Dae-Hui Ahn;Tae-Jun Kim
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.2
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    • pp.511-516
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    • 2024
  • The recently enacted detailed guidelines on the performance evaluation of track facilities presented the necessary requirements regarding the evaluation procedures and implementation methods of track performance evaluation. However, the grade of rail surface damage is determined by external inspection (visual inspection), and there is no choice but to rely only on qualitative evaluation based on the subjective judgment of the inspector. Therefore, in this study, we attempted to develop a diagnostic application that can diagnose rail internal defects using rail surface damage. In the field investigation, rail surface damage was investigated and patterns were analyzed. Additionally, in the indoor test, SEM testing was used to construct image data of rail internal damage, and crack length, depth, and angle were quantified. In this study, a deep learning model (Fast R-CNN) using image data constructed from field surveys and indoor tests was applied to the application. A rail surface damage diagnosis application (App) using a deep learning model that can be used on smart devices was developed. We developed a smart diagnosis system for rail surface damage that can be used in future track diagnosis and performance evaluation work.

A Study for Evaluation of Performance and Influence Factors for Steel Pipe Supports ( I ) (강제파이프서포트의 성능평가 및 영향요인에 대한 연구( I ))

  • Hwang Jung-Hyun;Shin Sang-Tae;Yun Sang-Moon;Kim Kyung-Hwa
    • Journal of the Korea Concrete Institute
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    • v.16 no.2 s.80
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    • pp.139-146
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    • 2004
  • Recently, interest on the performance of the construction temporary equipment have been greatly increased. Since the application of the 'Performance Test Code' for the equipment in 1992 according to the Industrial Safety and Health Act, a basic study of Steel Pipe Supports have been carried out for the last 2 years based on the Performance Test Results. The present code specification for the Steel Pipe Supports and research status are introduced. So far, total 849 specimen have been examined on their outer and inner pipe's length, thickness, their overlapping length, and their load carrying capacities. The test was conducted separately into two groups - used and new equipment, and it was found that the used ones revealed a decrease on their load carrying capacity, almost $10\%$ compared to the new ones. Considering this fact, it is strongly recommended to ensure the quality of the equipment before use at the jobsite. First of all, based on this basic investigation, the statistical values on the Steel Pipe Supports are suggested and further analysis on the effect of each component is in progress. It is, however, expected that this report can be used as a basic information on the Steel Pipe Supports.

The Development of High Pressure Long Distance Fire-fighting Hose with Phosphorescent Performance (축광 성능을 갖는 고압용 장거리 호스 개발에 관한 연구)

  • Han, Yong-Taek;Na, Byung-Gyun;Choi, Jin-Seong;Min, Se-Hong
    • Fire Science and Engineering
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    • v.31 no.5
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    • pp.63-69
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    • 2017
  • This study describes the development of a long-distance hose for ultra-high pressure operation, which can be used in conjunction with an ultra-high pressure pump and can be effectively applied to the fire suppression of high-rise buildings and a long, large tunnels. Also, it has phosphorescent properties, which can help to secure the withdrawal route of the fire-fighters when they are threatened by the fire. We developed an ultra-high pressure hose aiming at a pressure of 3 MPa and a flow rate of 2000 lpm and developed an ultra-high pressure fire hose that can withstand this very high pressure by using a double jacket, triple polyurethane coating and warf (Wp) of 52. In order to ensure the performance of the developed ultra-high pressure hose, its structure, appearance, leakage at high pressure, length and elongation were inspected by a certified certification agency, who also subjected it to a peeling test, friction test, breaking pressure test and free fall test. Also, it was studied in addition to the luminescent high-pressure hose for fire-fighting. In the phosphorescence test, the luminance measurement value was more than the reference value of the luminance test after 40 minutes, which confirmed that its performance was satisfactory for fire-fighting products. In the future, if such an ultra-high pressure fire hose were commercialized and applied in the field, it could contribute to securing improved fire suppression and safer exit from fires, as compared to the fire hoses currently used in the suppression of fires in skyscraper buildings and long tunnels.

A study on the methods of identifying and verifying the causes of defects on rock bolt stressmeter and rod extensometer (터널계측용 록볼트축력계와 지중변위계의 불량원인 파악과 검증방법에 대한 연구)

  • Kim, Yeong-Bae;Noh, Won-Seok;Lee, Seong-Won;Jeon, Hunmin;Lee, Kang-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.5
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    • pp.411-429
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    • 2022
  • Instrumentations are essential in NATM tunnels, however measuring instruments are installed and applied without performance verification procedures due to insufficient research on methods, procedures, regulations, etc. to verify the reliability of the measuring instruments. In this study, domestic and foreign regulations relating to the verification and calibration of instruments were investigated and necessities for accreditation standards were proposed. In order to identify the causes of the defects, an external inspection was performed on rock bolt stressmeter and rod extensometer, which are measuring instruments with relatively complex structures. For verifying the performance of these instruments, verification devices were developed that can load step-by-step and the causes of defects were identified in measuring instruments of nine domestic manufacturers. Through the performance test, a number of measuring instruments were found to be defective. It was important to test the performance of the instruments in the state of a finished product and accordingly performance inspection methods and procedures were proposed. The results of this study are expected to help preparing related regulations for verifying instrument performance and selecting instruments in the field.

Implementation of a Virtual Environment Data Representation Interface (가상환경 데이터 표현 인터페이스 구현)

  • Lee, Myeong-Won;Lee, Min-Geun;Lee, Sol-Me;Leem, Tai-Jin;Kim, Sung-Gon
    • Journal of the Korea Computer Graphics Society
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    • v.10 no.3
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    • pp.9-16
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    • 2004
  • 가상환경의 표현 정보가 의미있는 데이터로서 사용되게 하기 위해서는 지구상 모든 물체를 유일하게 정의하고 표현할 수 있는 데이터 구성 체계가 요구된다. 이를 위해서는 화면에 표현할 물체의 속성 정보가 표준화된 기술 방법에 따라서 표현되어야 한다. 이것은 가상환경 정보가 실세계 정보처리 분야에서 의미있는 데이터로서 유효하게 사용되도록 하기 위해서 모든 물체에 대한 고유한 물리적 정보 기술 방법이 고려되어야 함을 의미한다. 여기에는 물체 표현에 필요한 외관에 관한 정보 뿐 아니라 물체의 내부 표현을 포함하여 물체의 기능 및 성능 표현, 길이 및 무게, 지리적 위치 등의 속성 정보까지 모두 표현되고 관리될 수 있어야 한다. 본 논문에서는 이와 같은 속성 기술 방법을 위해서 lSO/IEC JTC1 SC24 WG8에서 표준화작업을 진행하고 있는 SEDRIS를 이용하여 물체의 모습과 속성을 표현하는 데이터구조를 가시화하고 이 데이터구조에 따라 물체의 모습을 렌더링하고 조작하는 가상환경 표현 인터페이스 구현에 대해 설명한다.

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A study on forming analysis for the soft pipe bending process of thickness guarantee (연질파이프의 두께보증형 벤딩공정에 대한 성형해석에 대한 연구)

  • Jung, Dong-Won;Jeong, Ji-Hyun;Cho, Jong-Rae
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.1
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    • pp.66-71
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    • 2013
  • Soft bending pipe is widely used for freezing equipment and shipbuilding. These pipe have some problems that they cause occasionally outside wrinkle, crack, wall thinning phenomena. However, vending machines which have been made to solve the problems completely, are not yet. In this study, to settle these problems, we proved the effectiveness of the self-made mandrel by results of simulation as the basic for the development of precision high-quality vending machine ; presents the solution method of the wall thinning phenomena by analyzing circular deformation and damage of bending pipe.