• 비파괴검사학회지
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• 제9권1호
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• pp.98-105
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• 1989

Detection of creep damages in centrifugally cast HK-40 reformer furnace catalyst tube is a common problem for the safety and scheduled operation of chemical plants. This study was focused on the development of an automatic ultrasonic scanning device with which the creep damage of welded zone of HK-40 reformer tubes is detected and evaluated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.189-192
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• 2008

콘크리트 교량에서 수행되는 기존 점검방법은 점검자가 현장에서 교량의 외관상태를 기록한 다음 내업을 통해서 수작업으로 외관조사망도를 작성하는 과정으로 진행된다. 하지만, 열악한 현장작업 여건으로 인해 획득되는 데이터는 객관성과 신뢰도가 떨어진다는 문제점이 있다. 본 연구에서는 이러한 문제점을 개선하기 위하여 외관조사결과를 자동으로 추출하는 이미지 처리 프로그램을 개발하였다. 이 프로그램은 교량으로부터 획득한 디지털 이미지를 처리하고 분석하며, 결과의 입출력 및 관리하는 데까지의 모든 관련 프로그램을 통칭한다. 프로그램 개발을 위하여 디지털 이미지의 크기와 카메라 배율간의 관계 분석, 균열 분석 알고리즘 개발, 이미지의 해상도 및 정밀도 분석 등의 연구가 수행되었다. 최초 계획에서는 이미지 처리를 통하여 균열망도를 자동으로 구현하도록 설계하였지만, 데이터의 용량과 이미지 처리의 기술적인 한계 그리고 콘크리트 표면의 여러 가지 조건에 등에 따라 결과의 신뢰도가 많이 차이가 난다는 것을 확인하였다. 따라서 결과를 정확하게 추출하기 위하여 자동판독 프로그램을 근간으로 하면서 사용자에 의해 수정작업이 가능하도록 프로그램을 보완하였다.

• 한국압력기기공학회 논문집
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• 제6권1호
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• pp.37-42
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• 2010

The stay cylinder weld at the steam generator of Korean Standard Nuclear Power Plants is safety class I component and is subjected to be inspected by the volumetric examination such as ultrasonic method. As accessibility of this area is limited due to the narrow space and high radiation, the existing manual inspection method involves various difficulties. Moreover operators may be exposed to internal contamination by contaminated dust during the surface buffing process to improve the inspection reliability of this area. Recently the new automatic inspection system for stay cylinder welds has been developed. The inspection system basically consists of a driving assembly, data acquisition device and signal processing units. The driving assembly is classified by 1) the scanner for inspecting and buffing the weld, 2) pillars for guiding the scanner and 3) the base frame for loading and supporting pillars. The scanner has 4 sensor modules to inspect in 4 refracted angles and 4 incident directions. These components can be inserted into the skirt of the stay cylinder through the manway hole and assembled easily by one-touch in the skirt. Data acquisition device and signal processing units developed in previous works are also newly upgraded for better processing of data analysis and evaluation. The system has been successfully demonstrated not only in the mock-up but also in the field. In this paper, newly developed inspection system for the stay cylinder weld of the steam generator is introduced and their field applications are discussed.

• Journal of Platform Technology
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• 제11권6호
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• pp.13-20
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• 2023

Regularly inspecting vehicle tires' condition is imperative for driving safety and comfort. Poorly maintained tires can pose fatal risks, leading to accidents. Unfortunately, manual tire visual inspections are often considered no less laborious than employing an automatic tire inspection system. Nevertheless, an automated tire inspection method can significantly enhance driver compliance and awareness, encouraging routine checks. Therefore, there is an urgency for automated tire inspection solutions. Here, we focus on developing a deep learning (DL) model to predict cracked tires. The main idea of this study is to demonstrate the comparative analysis of DenseNet121, VGG-19 and EfficientNet Convolution Neural Network-based (CNN) Transfer Learning (TL) and suggest which model is more recommended for cracked tire classification tasks. To measure the model's effectiveness, we experimented using a publicly accessible dataset of 1028 images categorized into two classes. Our experimental results obtain good performance in terms of accuracy, with 0.9515. This shows that the model is reliable even though it works on a dataset of tire images which are characterized by homogeneous color intensity.

• Computers and Concrete
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• 제32권6호
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• pp.615-623
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• 2023

Crack detection is an essential method to ensure the safety of dam concrete structures. Low-quality crack images of dam concrete structures limit the application of neural network methods in crack detection. This research proposes a modified attentional mechanism model to reduce the disturbance caused by uneven light, shadow, and water spots in crack images. Also, the focal loss function solves the small ratio of crack information. The dataset collects from the network, laboratory and actual inspection dataset of dam concrete structures. This research proposes a novel method for crack detection of dam concrete structures based on the U-Net neural network, namely AF-UNet. A mutual comparison of OTSU, Canny, region growing, DeepLab V3+, SegFormer, U-Net, and AF-UNet (proposed) verified the detection accuracy. A binocular camera detects cracks in the experimental scene. The smallest measurement width of the system is 0.27 mm. The potential goal is to achieve real-time detection and localization of cracks in dam concrete structures.

• 한국측량학회지
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• 제40권5호
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• pp.413-419
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• 2022

지하공간의 개발이 활발해짐에 따라 최근에는 지하와 관련된 안전사고가 자주발생하고 있다. 이와 관련하여 국토교통부에서는 『지하안전관리에 관한 특별법』(2018.01.01. 시행, 이하 지하안전법)을 시행하고 있다. 지하안전법의 핵심이 되는 내용 중에는 현재 우리나라에서 지하공간에 존재하는 지하시설물, 지하구조물, 지반의 지하정보를 3차원으로 가시화 할 수 있도록 지하공간통합지도를 구축하고 이를 활용하는 것을 포함하고 있다. 본 연구는 지하공간통합지도 중 3차원의 지하구조물 데이터를 대상으로 3차원 모델 생성 후 이를 빠르게 검수할 수 있는 프로그램을 개발하는 것을 목적으로 한다. 이를 위하여 우선 3차원 지하구조물 데이터를 생성하고 자동 검수하는 기술에 대하여 국내·외 현황을 조사하였다. 핵심이 되는 연구내용으로는 지하공간통합지도를 구축할 때 3차원 지하구조물의 검수기준에 따라 자동으로 3차원 모델 품질을 검수하는 프로그램을 개발하였다. 본 연구를 통하여 현재 수작업 방식으로 진행하고 있는 3차원 모델 검수과정을 98% 이상 자동화함으로써 지하공간통합지도 지하구조물의 3차원 모델의 품질향상을 도모할 수 있을 것으로 기대된다.

• 비파괴검사학회지
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• 제5권1호
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• pp.34-47
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• 1985

The developing country, KOREA where does not possess the natural resources for traditional energy such as oil and gas, so. The nuclear energy is the most single reliable source available for closing the energy gap. For these reason, It is inavoidable to construct the nuclear power plant and to develop technology related nuclear energy. The rate of operation in large nuclear power facilities depends upon the performance of work system through design and construction, and also the applied technology. Especially, it is the most important element that safety and reliability in operation of nuclear power plant. In view of this aspects, Nuclear power plant is performed severe examinations during preservice and inservice inspection. This study provide an automation of analysis for volumetric examination which is required to nuclear power plant components. It is composed as follows: I. Introduction II. Inservice Inspection of Nuclear Power Plant ${\ast}$ General Requirement. ${\ast}$ Principle and Methods of Ultrasonic Test. ${\ast}$ Study of Flaw Evaluation and Design of Classifying Formula for Flaws. III. Design of Automation for Flaw Evaluation. IV. An Example V. Conclusion In this theory, It is classifying the flaws, the formula of classifying flaws and the design of automation that is the main important point. As motioned the above, Owing to such as automatic design, more time could be allocated to practical test than that of evaluation of defects, Protecting against subjective bias tester by himself and miscalculation by dint of various process of computation. For the more, adopting this method would be used to more retaining for many test data and comparative evaluating during successive inspection intervals. Inspite of limitation for testing method and required application to test components, it provide useful application to flow evaluation for volumetric examination. Owing to the characteristics of nuclear power plant that is highly skill intensive industry and has huze system, the more notice should be concentrated as follows. Establishing rational operation plan, developing various technology, and making the newly designed system for undeveloped sector.

• Nuclear Engineering and Technology
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• 제44권4호
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• pp.421-428
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• 2012

Analog instrument and control systems in nuclear power plants have recently been replaced with digital systems for safer and more efficient operation. Digital instrument and control systems have adopted various fault-tolerant techniques that help the system correctly and safely perform the specific required functions regardless of the presence of faults. Each fault-tolerant technique has a different inspection period, from real-time monitoring to monthly testing. The range covered by each faulttolerant technique is also different. The digital instrument and control system, therefore, adopts multiple barriers consisting of various fault-tolerant techniques to increase the total fault detection coverage. Even though these fault-tolerant techniques are adopted to ensure and improve the safety of a system, their effects on the system safety have not yet been properly considered in most probabilistic safety analysis models. Therefore, it is necessary to develop an evaluation method that can describe these features of digital instrument and control systems. Several issues must be considered in the fault coverage estimation of a digital instrument and control system, and two of these are addressed in this work. The first is to quantify the fault coverage of each fault-tolerant technique implemented in the system, and the second is to exclude the duplicated effect of fault-tolerant techniques implemented simultaneously at each level of the system's hierarchy, as a fault occurring in a system might be detected by one or more fault-tolerant techniques. For this work, a fault injection experiment was used to obtain the exact relations between faults and multiple barriers of faulttolerant techniques. This experiment was applied to a bistable processor of a reactor protection system.

• International Journal of Advanced Culture Technology
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• 제8권2호
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• pp.58-67
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• 2020

In this paper, the maintenance training manual of EV vehicle was produced by utilizing digital twin technology and various sensors such as IR-based light house tracking and head tracker. In addition, through digital twin technology and VR to provide high immersiveness to users, sensory content creation technology was secured through animation and effect realization suitable for EV vehicle maintenance situation. EV vehicle maintenance training manual is 3D engine programming and real-time creation of 3D objects and minimization of screen obstacles and selection of specific menus in virtual space in the form of training simulation. In addition, automatic output from the Head Mount Display (HUD), EV vehicle maintenance and inspection, etc., user can easily operate content was produced. This technology development can enhance immersion to users through implementation of detailed scenarios for maintenance / inspection of EV vehicles" and 3D parts display by procedure, realization of animations and effects for maintenance situations. Through this study, familiarity with improving the quality of education and safety accidents and correct maintenance process and the experienced person was very helpful in learning how to use equipment naturally and how to maintain EV vehicles.

• Computers and Concrete
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• 제23권6호
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• pp.445-457
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• 2019

Cracks are an important distress of concrete bridges, and may reduce the life and safety of bridges. However, the traditional manual crack detection means highly depend on the experience of inspectors. Furthermore, it is time-consuming, expensive, and often unsafe when inaccessible position of bridge is to be assessed, such as viaduct pier. To solve this question, the real-time automatic crack detecting system with unmanned aerial vehicle (UAV) become a choice. This paper designs a new automatic detection system based on real-time comprehensive image processing for bridge crack. It has small size, light weight, low power consumption and can be carried on a small UAV for real-time data acquisition and processing. The real-time comprehensive image processing algorithm used in this detection system combines the advantage of connected domain area, shape extremum, morphology and support vector data description (SVDD). The performance and validity of the proposed algorithm and system are verified. Compared with other detection method, the proposed system can effectively detect cracks with high detection accuracy and high speed. The designed system in this paper is suitable for practical engineering applications.