• Steel and Composite Structures
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• 제31권3호
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• pp.233-242
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• 2019

Early detection of damage bonding state such as insufficient bonding strength and interface partial contact defect for the explosive clad pipe is crucial in order to avoid sudden failure and even catastrophic accidents. A generalized and efficient model of the explosive clad pipe can reveal the relationship between bonding state and vibration characteristics, and provide foundations and priory knowledge for bonding state detection by signal processing technique. In this paper, the slender explosive clad pipe is regarded as two parallel elastic beams continuously joined by an elastic layer, and the elastic layer is capable to describe the non-uniform bonding state. By taking the characteristic beam modal functions as the admissible functions, the Rayleigh-Ritz method is employed to derive the dynamic model which enables one to consider inhomogeneous system and any boundary conditions. Then, the proposed model is validated by both numerical results and experiment. Parametric studies are carried out to investigate the effects of bonding strength and the length of partial contact defect on the natural frequency and forced response of the explosive clad pipe. A potential method for identifying the bonding quality of the explosive clad pipe is also discussed in this paper.

• 한국진공학회지
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• 제2권4호
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• pp.404-409
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• 1993

Adorption of nitric oxide on the Pt(III) surface sputtered by Ar-ion has been studied using thermal desorption spectroscopy and Auger electron spectroscopy. Ar-ion sputtering creates a precursor state of ($NO\beta$ stage) adsorbe dat defect sites. The precursor state is characterized by the terminal bent species . At low coverge mos 샐 adsorbed NO dissociates . And as increasing the coverage, the fraction of dissociation remains about 80%.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1096-1100
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• 2003

A fast Q-tensor method, which can model the defect dynamics in a liquid crystal director field is presented. The method is used to model the defect dynamics occurring during the "warm-up" of a ${\pi}-cell$ device.

• 한국건축시공학회지
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• 제10권2호
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• pp.81-88
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• 2010

우리나라는 공동주택 관리에 관한 규칙에 의거하여 하자보수 보증금을 예치하고 이를 기반으로 공동주택 입주자들의 하자보수 요구에 대응하고 있다. 현재 민간주택사업자들의 경우 막대한 시간과 비용을 들여 구축한 자사의 브랜드 이미지 고수를 위하여 자신들이 건설한 주택의 품질확보 및 A/S에 큰 노력을 기울이고 있다. 그러나 현재 하자보수에 투입되는 비용중에는 순수한 하자보수에 투입되는 비용이외에 단지내 미화 등 입주민들의 비합리적인 요구사항에 투입되는 비용 또한 있는 것이 사실이다. 따라서 본 연구에서는 39개단 단지를 대상으로 하자보수에 투입되었던 실적자료를 근거로 실제로 하자보수에 투입된 하자성비용과 단지내 미화 등 하자보수와 연관성이 적은 기타비용인 민원성 비용의 사용실태를 분석하였다. 분석결과 하자성비용과 민원성 비용이 거의 비슷한 비율을 차지하고 있으며, 민원성비용이 오히려 높은 결과를 보였다. 이러한 분석결과는 입주자들의 비합리적인 요구 및 주택사업자들의 근시안적인 대처에 기안하는 것으로 사료된다.

• 한국컴퓨터정보학회논문지
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• 제25권3호
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• pp.19-26
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• 2020

일반적으로 품질 관리는 많은 제조 공정, 특히 주조 또는 용접과 관련된 공정의 기본 구성 요소가 된다. 그러나 사람이 일일이 수동으로 품질 관리 절차를 하는 것은 종종 시간이 걸리고 오류가 발생하기 쉽다. 최근 고품질 제품에 대한 요구를 만족시키기 위해 지능형 육안 검사 시스템의 사용이 생산 라인에서 필수적이 되고 있다. 본 논문에서는 이를 위해 딥 러닝 기반의 ShuffleDefectNet 결함 감지 시스템을 제안하고자 한다. 제안된 결함 검출 시스템은 NEU 데이터 세트의 결함 검출에 대한 여러 최신 성능들보다 높은 평균 정확도 99.75% 정도를 얻는다. 이 논문에서 여러 다른 트레이닝 데이터로부터 최상의 성능을 탐지하고 탐지 성능을 관찰하였다. 그 결과 ShuffleDefectNet의 전체 아키텍처를 사용할 때 정확성과 속도가 크게 향상됨을 알 수 있었다.

• Journal of Information Processing Systems
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• 제14권6호
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• pp.1331-1346
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• 2018

Aiming at the problem that the gradient-based edge detection operators are sensitive to the noise, causing the pseudo edges, a triqubit-state measurement-based edge detection algorithm is presented in this paper. Combing the image local and global structure information, the triqubit superposition states are used to represent the pixel features, so as to locate the image edge. Our algorithm consists of three steps. Firstly, the improved partial differential method is used to smooth the defect image. Secondly, the triqubit-state is characterized by three elements of the pixel saliency, edge statistical characteristics and gray scale contrast to achieve the defect image from the gray space to the quantum space mapping. Thirdly, the edge image is outputted according to the quantum measurement, local gradient maximization and neighborhood chain code searching. Compared with other methods, the simulation experiments indicate that our algorithm has less pseudo edges and higher edge detection accuracy.

• Journal of Welding and Joining
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• 제16권6호
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• pp.77-85
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• 1998

Effects of non-cleaning and cleaning fluxes on the wetting properties and defects at flow soldered joints were investigated. Non-cleaning flux (R-type of 3.3% solid content) and cleaning flux (RMA-type of 15% solid content) were used. Wetting test was accomplished by wetting balance method with changing surface state of wetting specimen, CU. Sn-37%Pb solder was used for wetting test and flow soldering. As experimental results, the wetting time for vertical force from the surface tension being zero was mainly affected by surface state of the wetting specimen. Non-cleaning flux had a good wettability compared with cleaning flux. In case of non-cleaning flux, conveyor speed had a great affection to defects of bridge, icicle, and poor solder.

• 한국공작기계학회논문집
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• 제13권6호
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• pp.23-28
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• 2004

Impact behavior of polycarbonate in various defect state was investigated using an instrumented impact tester. A method of analyzing raw impact data was developed and successfully demonshsted the impact behavior in terms of load-displacement and energy-displacement curves. This technique was shown to be capable of separating defect no-defect initiated fractures as well as their propagation behaviors.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.262-267
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• 2002

Impact behavior of polycarbonate in various defect state was investigated using an instrumented impact fester. A mettled of analyzing raw impact data was developed and successfully demonstrated the impact behavior in terms of load-displacement and energy-displacement curves. This technique was shown to be capable of separating defect, no-defect initiated fractures as well as their propagation behaviors.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.344-354
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• 2015

In order to study the development of partial discharge (PD) under typical protrusion defects in gas-insulated switchgear, we applied step voltages on the defect and obtained the ${\varphi}-u$ and ${\varphi}-n$ spectrograms of ultra-high frequency (UHF) PD signals in various PD stages. Furthermore, we extracted seven kinds of features to characterize the degree of deterioration of insulation and analyzed their values, variation trends, and change rates. These characteristics were inconsistent with the development of PD. Hence, the differences of these features could describe the severity of PD. In addition, these characteristics could provide integrated characteristics regarding PD development and improve the reliability of PD severity assessment because these characteristics were extracted from different angles. To explain the variation laws of these seven kinds of parameters, we analyzed the relevant physical mechanism by considering the microphysical process of PD formation and development as well as the distortion effect generated by the space charges on the initial field. The relevant physical mechanism effectively allocated PD severity among these features for assessment, and the effectiveness and reliability of using these features to assess PD severity were proved by testing a large number of PD samples.