• 비파괴검사학회지
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• 제36권2호
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• pp.155-159
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• 2016

Eddy current testing (ECT) is an important nondestructive testing technology for the inspection of flaws in conductive materials. However, this widely used technology is not suitable for inspecting lamination when a conventional pancake coil is used because the eddy current (EC) generated by the pancake coil is parallel to the lamination and will not be perturbed. A new method using a rectangular coil placed vertical to the work piece is proposed for lamination detection. The vertical sections of the rectangular coil induce ECs that are vertical to the lamination and can be perturbed by the lamination. A parametric study of a rectangular coil by finite element analysis was performed in order to examine the capability of generating vertical EC.

• 비파괴검사학회지
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• 제22권6호
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• pp.627-636
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• 2002

Identification and sizing of surface breaking vertical cracks using angle beam ultrasonic testing in practical situation quite often become very difficult tasks due to the presence of non-relevant signals caused by geometric reflectors. The present work introduces effective and systematic approaches to take care of such a difficulty by use oi angle beam ultrasonic testing models that can predict the expected signals from various targets very accurately. Specifically, the model-based TIFD (Technique for Identification of Flaw signals using Deconvolution) is Proposed for the identification of the crack tip signals from the non-relevant geometric reflection signals. In addition, the model-based Size-Amplitude Curve is introduced for the reliable sizing of surface breaking vertical cracks.

• Journal of Information Processing Systems
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• 제4권1호
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• pp.33-40
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• 2008

Traceability has been held as an important factor in testing activities as well as model-driven development. Vertical traceability affords us opportunities to improve manageability from models and test cases to a code in testing and debugging phase. This paper represents a vertical test method which connects a system test level and an integration test level in testing stage by using UML. An experiment how traceability works to effectively focus on error spots has been included by using concrete examples of tracing from models to the code.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.622-627
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• 2001

The paper presents the possibilities of a wide practical application of the modal analysis methods in dynamic testing of vertical pump. A pneumatic impact of testing vertical pumps submerged under deep water was developed and successfully applied. The problem with the enviroment is the it causes significants changes in modal parameters, compared with those in the airenviroment.

• 한국컴퓨터정보학회논문지
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• 제13권2호
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• pp.19-29
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• 2008

단위 시험은 모듈의 소스 코드를 면밀히 검토하면서 논리적 오류나 문장 오류 등이 있는지 분석하는 화이트박스 시험이 가능하다. 반면 시스템 수준의 기능 시험은 규모가 크기 때문에 시험 데이터를 입력한 후 출력된 결과가 예상 결과와 같은지 비교하는 블랙박스 시험이 주를 이룬다. 이러한 시스템 시험 단계에서 사용하는 블랙박스시험은 오류를 발견하더라고 수정을 위해 소스 코드를 추적하기 어려운 문제점이 있다. 뿐만 아니라 시스템 시험 단계에 화이트박스 시험을 사용하는 것은 시험 대상의 추상 수준 달라 쉽지 않다. 이에 본 논문에서는 시스템의 기능처럼 높은 추상 수준을 시험 대상으로 하되 소스 코드 수준까지 화이트박스 스타일로 시험할 수 있는 현실적이고 통합된 시스템 수준의 수직적 시험에 대해 제안한다. 그리고 어떻게 수직적 시험을 적용하는지 UML명세 모델에서 소스코드까지 오류를 추적하는 방법을 사례를 통해 설명하고 더불어 오류 추적의 효과성을 보였다.

• 정보처리학회논문지D
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• 제14D권7호
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• pp.753-762
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• 2007

추적이란 개념은 모델 중심의 개발에서만이 아니라 테스트를 위하여 매우 중요한 요소이다. 수직적인 추적은 모델로부터 테스트와 디버깅 단계에 이르기까지 시스템을 잘 관리할 수 있게 한다. 또한 테스트 단계에서 발견한 결함에 대한 오류를 추적할 때 발생하는 추상 수준의 오르내림을 추적가능성으로 극복하게 한다. 이 논문에서는 시스템 테스트 수준과 통합 테스트 수준에서 UML을 이용하여 수직적으로 연결하여 더욱 엄격한 테스트가 되는 방법을 제안한다. 실험을 통하여 추적이란 개념이 어떻게 작동하며 오류 부분을 찾아내는지 얼마나 효과적인지 보이며 모델에서 코드까지의 구체적인 사례를 이용하여 방법을 소개한다.

• 한국정밀공학회지
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• 제18권11호
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• pp.34-41
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• 2001

This study is to investigate the energy absorption characteristics of CFRP(Carbon-Fiber Reinforced Plastics) tubes on static and dynamic tests. Axial static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine) and dynamic compression tests have been utilized using an vertical crushing testing machine. When such tubes are subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that could control the crushing process. The collapse characteristics and energy absorption have been examined for various tubes. Energy absorption of the tubes are increased as changes in the lay-up which may increase the modulus of tubes. The results have been varied significantly as a function of ply orientation and interlaminar number.

• 한국컴퓨터정보학회논문지
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• 제20권10호
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• pp.23-29
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• 2015

In this paper, we suggest a method of detecting defects by applying Hough transform and least squares on ceramic images obtained from non-destructive testing. In the ceramic images obtained from non-destructive testing, the background area, where the defect does not exist, commonly show gradual change of luminosity in vertical direction. In order to extract the background area which is going to be used in the detection of defects, Hough transform is performed to rotate the ceramic image in a way that the direction of overall luminosity change lies in the vertical direction as much as possible. Least squares are then applied on the rotated image to approximate the contrast value of the background area. The extracted background area is used for extracting defects from the ceramic images. In this paper we applied this method on ceramic images acquired from non-destructive testing. It was confirmed that extracted background area could be effectively applied for searching the section where the defect exists and detecting the defect.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.315-319
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• 2004

This paper presents the integrity evaluation method of the windings in cast resin transformers using vertical thermal distribution analysis. The method is to compare the temperature distribution in a sound condition specimen with that in the failure condition specimen layer-shorted by accelerated testing. The temperature distribution was acquisited by a infrared thermography system, and the Arrhenius equation was adopted to the accelerated testing. The proposed method may be available to detect the failures in cast resin transformers.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.640-648
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• 2004

This paper describes a new magnetization method for non-destructive testing with magneto-optical sensor (denoted as MO sensor) which have the following characteristic : high observation sensitivity, independence of the crack orientation, and precise imaging of a complex crack geometry such as multiple cracks. When a magnetic field is applied normally to the surface of a specimen which is significantly larger than its defects, approximately the same magnetic charge per unit area occurs on the surface of the specimen. If there is a crack in the specimen, magnetic charge per unit area has the same value at the bottom of the crack. The distribution of the vertical component of the magnetic flux density, B$\_$Z/, is almost uniform over the no-crack area (denoted as B$\_$Z,BASE/), while the magnetic flux density is smaller in the surroundings of the crack(denoted as B$\_$Z,CRACK/) If B$\_$Z, BASE/ is a bit larger than the saturated magnetic flux density of the MO sensor (B$\_$s/) , then small magnetic domains occur over the crack area and a large domain over the non-crack area because B$\_$Z,CRACK/ is smaller than B$\_$s/.