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딥러닝 기반 선박 부식 자동 검출을 위한 이미지 전처리 방안 연구
윤광호,오상진,신성철 한국산업융합학회 2022 한국산업융합학회 논문집 Vol.25 No.4
Corrosion can cause dangerous and expensive damage and failures of ship hulls and equipment. Therefore, it is necessary to maintain the vessel by periodic corrosion inspections. During visual inspection, many corrosion locations are inaccessible for many reasons, especially safety’s point of view. Including subjective decisions of inspectors is one of the issues of visual inspection. Automation of visual inspection is tried by many pieces of research. In this study, we propose image preprocessing methods by image patch segmentation and thresholding. YOLOv5 was used as an object detection model after the image preprocessing. Finally, it was evaluated that corrosion detection performance using the proposed method was improved in terms of mean average precision.
윤광호,김완종,한상균,한국일,남궁우,한만덕 한국통합생물학회 2015 Animal cells and systems Vol.19 No.1
Polydeoxyribonucleotide (PDRN) is an agonist of the A2A adenosine receptors. We evaluated the effects of PDRN on liverregeneration induced by partial hepatectomy (PH) in rats, focusing on cell proliferation. Proliferating cell nuclear antigen(PCNA) as an indicator of cell proliferation was targeted to determine whether PDRN treatment could promote proliferationof hepatic cells in regenerating liver. Male Sprague-Dawley rats were divided into three groups: normal group (n = 3)without PH (sham operated), control groups (n = 12) with saline injection after PH, and experimental groups (n = 12) withi.p. injection of 8 mg/kg of PDRN immediately after PH. Light microscopically, liver regeneration induced by PH involvedproliferation of various hepatic cells including parenchymal cells and Kupffer cells. The disintegration (1 or 2 days afterPH) and remodeling (4 days after PH) of hepatic plate and increase of sinusoids (6 days after PH) were sequentiallyobserved. These regenerative processes occurred relatively earlier in the experimental groups. By western blotting, theexpression of PCNA increased in the early stage, reached its peak at 1 and 2 days after PH, and decreased thereafter. Byimmunohistochemistry, the intensities of PCNA staining in the experimental groups were more obvious at various daysafter PH. By electron microscopy using immunogold labeling for PCNA, the gold particles were largely observed inheterochromatin and nucleolus in hepatic cells. The results of immunochemistry and western blotting for PCNA showed thesimilar pattern in most groups. These findings suggest that PDRN treatment to hepatectomized rat could accelerate liverregeneration through rapid cell proliferation.
윤광호 선문대학교 신학대학 2001 선문대학교 신학대학논문집 Vol.2000 No.-
Inorganic polymers such as polycarbosilanes and polysilanes have been employed for many special applications. Polycarbosilanes have been used as SiC ceramic precursor. Polysilanes possess peculiar optoelectronic properties due to σ-conjugation along the silicon backbone and have received great attention as silicon-containing ceramic precursors, luminesecnt materials, deep-UV positive photoresists, electroconductors, and photoinitiators. The conventional synthetic method to prepare high-molecular-weight polysilanes is the Wurtz coupling reaction of dichlorosilanes using an alkali metal dispersion in either toluene-refluxing temperature or supersonic activation. However, the heterogeneous reductive dehalocoupling method has some limitations such as intolerance of some functional groups, lack of reproducibility, and difficulties in controlling stereochemistry and molecular weight. Recently, the group 4 metallocene-catalyzed dehydrocoupling of hydrosilanes to polysilancs was discovered. Considerable efforts have been made to increase the molecular weight of the polysilanes in the homogeneous catalytic dehydrocoupling of hydrosilanes. We reported the dehydropolymerization of various hydrosilanes catalyzed by group 4 metallocene complexes generated in situ from Cp_(2)MCI_(2)/Red-Al combination. Hydrosilation has been used to increase the molecular weight of polysilanes containing both Si-H and olefin moieties. Corriu et al. recently accounted the tunable dchydropolymerization of an ethylene disilane, 1,4-disilapentane to highly cross-linked insoluble polysilane as a silicon carbide precursor. We preliminarily noted the hydrogenation/dehydrocoupling of ethylene disilanes catalyzed by the Cp_(2)TiCl_(2)/Red-Al combination. Here we report the hydrogenation/hydrosilatiom/dehydrocoupling of 2,5-disilaoct-7l-ene (1) and the dehydrocoupling of 2,5-disilahexane (2), catalyzed by group 4 metallocene complexes generated in situ from Cp'_(2)MCl_(2)/ Hydride [Cp' = η^(5)-C_(5)H_(5)(Cp), η^(5)-C_(5)Me_(5)(Cp*); M=Ti, Zr, Hf; Hydride = Red-Al, N-Selectride] combination.
교류서보 전동기의 전류관측기를 이용한 속도 센서리스제어
윤광호,남문현 대한전기학회 2004 전기학회논문지 D Vol.53 No.6(D)
This paper proposed a new speed sensorless control method for AC servo motor, which is based on the current observer. Recently, the study in the estimation using a observer is being widely progressed. In order to prove the superiority of the current observer, we made a comparison between the simulation using current observer and that using Luenberger observer. And also, a comparative experiment of the speed control of the AC servo motor using a sensor and using current observer has been executed. The experiment result shows that the estimation using current observer is superior to the estimation using Luenberger observer or to the speed response using a sensor.
윤광호,남문현 대한전기학회 2005 전기학회논문지 D Vol.54 No.5(D)
The state observer is being used widely because it has the advantage of the guarantee of reliability on financial problem, over heating, and physical shock. However, an Luenberger observer and a Sliding observer have such problems that an experimenter needs to know dynamics and parameters of the system. And also, the high gain observer has such a problem that it has transient state at the beginning of the observation. In this paper, the Neuro observer is proposed to improve these problems. The proposed Neuro observer complement a problem that occur from increase of gain of High-gain observer in proportion to the square number of observable state variables. And also, the proposed Neuro observer can tune the gain obtained by differentiating observational error at transient state automatically by using the backpropagation training method to stabilize the observational speed. To prove a performance of the proposed observer, it is simulated that the comparison between the state estimate performance of the proposed observer and that of Sliding, High gain observer is made by using a sinusoidal input to the observer which consists of four layers in stable 2nd order system.
사용자 웹 사용 정보에 기반한 멀티 컨셉 네트워크의 생성
윤광호,윤태복,이지형 한국지능시스템학회 2008 한국지능시스템학회 학술발표 논문집 Vol.18 No.1
웹의 방대한 데이터에서 사용자에게 정보를 제공하기 위하여 다양한 연구가 시도되고 있다. 웹 사용 마이닝은 웹 사용자의 로그 정보를 기반으로 웹 페이지를 평가할 수 있는 유용한 방법이다. 하지만 기존의 웹 사용 마이닝을 이용한 웹 페이지 평가에는 사용자들의 다양한 성향 패턴을 무시한 일괄적인 모델을 생성하는데 주를 이루고 있다. 본 논문은 사용자 관심 키워드에 대한 웹 페이지 사용 정보를 수집하고 분석하여 멀티 컨셉 네트워크(Multi Concept Network MC-Net)를 생성한다. MC-Net은 사용자 관심 키워드에 기반한 다양한 성향 정보에 따른 웹 페이지 연결망을 제공한다. 생성된 MC-Net은 웹 페이지 추천을 위하여 유용하게 사용할 수 있으며, 실험을 통하여 제안하는 방법의 유효함을 확인하였다.