• Journal of Korea Multimedia Society
• /
• v.19 no.3
• /
• pp.633-641
• /
• 2016

Automatic defect inspection system is composed of the step in the pre-processing, defect candidate detection, and classification. Polarizing films containing various defects should be minimized over-detection for classifying defect blobs. In this paper, we propose a defect detection algorithm using a skewness of histogram for minimizing over-detection. In order to detect up defects with similar to background pixel, we are used the characteristics of the local region. And the real defect pixels are distinguished from the noise using the probability density function. Experimental results demonstrated the minimized over-detection by utilizing the artificial images and real polarizing film images.

• Journal of Ocean Engineering and Technology
• /
• v.3 no.2
• /
• pp.601-601
• /
• 1989

The behavior of fatigue was studied by using low carbon steel bar with microhole(artificial small defect) under the condition of rotary bending stress which is made artificially at smooth surface and round notch root. The results obtained can be summerized; The behavior of non-propagating cracks which are produced at both tips of small defect occurred to dissymmetry, and it is found to be double size of small defect. For the range of l>lc, threshold stress intensity is constant. However, for the range of l

• Journal of Ocean Engineering and Technology
• /
• v.3 no.2
• /
• pp.101-107
• /
• 1989

The behavior of fatigue was studied by using low carbon steel bar with microhole(artificial small defect) under the condition of rotary bending stress which is made artificially at smooth surface and round notch root. The results obtained can be summerized; The behavior of non-propagating cracks which are produced at both tips of small defect occurred to dissymmetry, and it is found to be double size of small defect. For the range of l>lc, threshold stress intensity is constant. However, for the range of l

• Carbon letters
• /
• v.16 no.3
• /
• pp.198-202
• /
• 2015

Carbon-supported Pt catalyst systems containing defect adsorption sites on the anode of direct methanol fuel cells were investigated, to elucidate the mechanisms of H₂ dissociation and carbon monoxide (CO) poisoning. Density functional theory calculations were carried out to determine the effect of defect sites located neighboring to or distant from the Pt catalyst on H₂ and CO adsorption properties, based on electronic properties such as adsorption energy and electronic band gap. Interestingly, the presence of neighboring defect sites led to a reduction of H₂ dissociation and CO poisoning due to atomic Pt filling the defect sites. At distant sites, H₂ dissociation was active on Pt, but CO filled the defect sites to form carbon π-π bonds, thus enhancing the oxidation of the carbon surface. It should be noted that defect sites can cause CO poisoning, thereby deactivating the anode gradually.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.195-198
• /
• 2001

Backside defect of plate structure may grow due to fatigue or overload to cause critical failure during operation, so it is important to detect this kind of defect in line. For this purpose, nondestructive, non-contact and highly sensitive method is required. ESPI and Shearography are considered as useful method to satisfy these requirements. In this paper, the possibility of application of ESPI and Shearography to detect the backside defect of steel plate and to quantify the defect size was tested. For the experiment, some steel plates with defect on the backside were prepared. Experimental results for these plates showed that location and size of defect could be detected correctly by both of ESPI and Shearography.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.27 no.2
• /
• pp.10-16
• /
• 2004

Data mining technique is the exploration and analysis, by automatic or semiautomatic means, of large quantities of data in order to discover meaningful patterns and rules. This paper uses a data mining technique for the prediction of defect types in manufacturing Process. The Purpose of this Paper is to model the recognition of defect type Patterns and Prediction of each defect type before it occurs in manufacturing process. The proposed model consists of data handling, defect type analysis, and defect type prediction stages. The performance measurement shows that it is higher in prediction accuracy than logistic regression model.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.08a
• /
• pp.180-187
• /
• 1999

This document illustrates the relationship between the wire rod wrinkle defect and the roll caliber design. The wrinkle defect is caused by the incongruent rolling conditions of the roll caliber design, the roll adjustment, and the extracting temperature. In this document, we restrict the study scope to the roll caliber design's effect on wrinkle defect at the base of real condition of the No.2 Wire Rod mill, POSCO. There has been wrinkle defect problem in the No.2 Wire Rod Mill, POSCO for many years. The engineers of the wire rod mill have been making efforts to solve the problem. As one of the efforts, we take the samples of the wire rod in the each stands of the 2'nd wire rod mill and then analyze the samples. Through the analysis, we find out the problem of the roll caliber design. So, we suggest the roll caliber design method to be more effective to weaken the wrinkle defect.

• IE interfaces
• /
• v.21 no.2
• /
• pp.151-160
• /
• 2008

Defect size distribution is a probability density function for the defects that occur on wafers or glasses during semiconductor/LCD fabrication. It is one of the most important information to estimate manufacturing yield using well-known statistical estimation methods. The defects are detected by automatic optical inspection (AOI) facilities. However, the data that is provided from AOI is not accurate due to resolution of AOI and its defect detection mechanism. It causes distortion of defect size distribution and results in wrong estimation of the manufacturing yield. In this paper, I suggest a size conversion method and a maximum likelihood estimator to overcome the vague defect size information of AOI. The methods are verified by the Monte Carlo simulation that is constructed as similar as real situation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.04a
• /
• pp.115-120
• /
• 2000

This study is on the application the image processing algorithm for inspection of the aluminium mill strip surface defect. The image of surface defect data was obtained using the CCD camera with the digital signal board. The edge was found from the difference of pixel intensity between the normal image and defect image. Two step were taken to find the edge in the image processing algorithm. First, noise was removed by using the median filter in the image. Second, the edge was sharpened in detail by using the sharpening convolution filter in the image. Canny algorithm was used to defect the exact edge. The defect section was separated from the original image is to find the coordination point p1 and p2 which include the defect image

• Journal of Chest Surgery
• /
• v.26 no.12
• /
• pp.904-908
• /
• 1993

Twelve patients had undergone repair of atrioventricular septal defects. Age at operation ranged from 2.4 years to 17 years[mean, 8.25 years]. Five patients were male and seven were female. Three patients had complete atrioventricular septal defect[Rastelli type A] associated with Down`s syndrome. One of the three patient with complete atrioventricular septal defect had tetralogy of Fallot. Three patients had the intermediate form and seven patients had the partial form. The primum atrial septal defect was closed with pericardial patch. The atrioventricular valve septal commissure[mitral cleft] was closed with pledgeted sutures. Three complete atrioventricular septal defect were undergone by two-patch technique. A crescent-shaped Dacron patch was used to occlude the ventricular septal defect. One patient of partial form was sudden death 5 days postoperatively. There were no another complications after surgery. One patient underwent reoperation for opened mitral cleft 2.5 years postoperatively. New York Heart Association functional class of patients was improved postoperatively.