• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.34-38
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• 2003

The large eddy simulation based Fire Dynamics Simulator was utilized to investigate the effects of the size of an opening on smoke removal performance for the three smoke control systems-ventilation purge, and extraction. Three different opening sizes, $r_A$=1, 2, and 3 were investigated while the flow rate remained 0.75 $m^3/s$ at the inlet or outlet depending on the systems. Increase of the opening size did not give a significant difference in the smoke removal rate for the three smoke control systems, though the increasing opening size slightly improved smoke removal. The extraction system was shown the best smoke control system, and the purge system yielded low performance compared to the other two systems for all the different opening sizes.

• Computers and Concrete
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• v.34 no.1
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• pp.49-61
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• 2024

The present study concerns a removal of chloride ions and structural behaviour of concrete beam at electrochemical chloride extraction (ECE). The electrochemical properties included 1000 mA/m2 current density for 2, 4 and 8 weeks. It was found that an increase in the duration of ECE resulted in an increase in the extraction rate of chlorides, in the range of 35-85%, irrespective of chloride contamination. In structural behaviour, the strength and maximum bending moment of specimen was always lowered by ECE. Moreover, the flexural rigidity and bending stiffness were reduced by the loss of effective cross-section area in the linear elastic range. Simultaneously, the inertia moment was substantially subjected to 70% loss of the cross-section by the tensile strain at the condition of the failure. However, a lower rate of the inertia moment reduction was achieved by ECE, implying the higher resistance to the cracking, but the higher risk of deformation.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1991.10a
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• pp.77-80
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• 1991

This paper proposes a new feature extraction method which is effectively used in character recognition, and validate the effectiveness through various computational methods for similiarity degree. To get feature vectors used in this method, Hough transform is applied to character image, which is used for edge extraction in image processing. By that transformation technique, strokes could be extracted and feature vectors constructed suitably. The characteristic of this method is solving the difficulties in stroke extraction through transform space analysis, which is induced by noise and blurring, and representing high recognition rate 99.3% within 10 candidates in relative low dimension.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.297-297
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• 2000

This paper proposed character recognition method by using DB Matching and Artificial Neural Network at the Gerber files. Gerber files are file for make PCB. But we also use the file to a program of extraction PCB position data. If the Gerber file recognized a character, the extraction PCB position data will be faster and also when the recognition rate is high, it can be possible to automatic extraction. We apply to the construction PCB Gerber file program and Simulation results are presented to verify the usefulness of the method.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.53-59
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• 1995

In a hot water extraction process, the flow pattern of upper region in a storage tank is a major reason of mixing between hot water and cold water. In this study, the temperature distribution in a storage tank was measured to predict the flow pattern of upper region, and the degree of stratification was analysed to the variables dominating a extraction process. And also, it was found that the degree of stratification improved expecially in a low flow rate in case of using modified distributor I(DMI) as a outlet port type.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2073-2078
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• 2007

This study was performed to develop a dryer for home clothes using thermoelectric module. The thermoelectric module was used as a heat source and a dehumidification device because it has heating part and cooling part at once. To design for maximizing the energy efficiency and the rate of dehumidification, the parameters of the dryer using thermoelectric module are heat capacity and air flow rate. This study showed that the thermoelectric module can be used in the clothes dryer and energy efficiency of clothes dryer be better than that of electric heating dryer.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.11a
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• pp.66-71
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• 2002

In Generally, a imbedding and extracting is good as watermark using a random dot image. In this paper, when the autostreogram which has some randomness is used watermark image, distortion rate is low and extraction rate is high. Using this quality, when any logo image is transformed to same image domain randomly, distortion rate is low and extraction rate is high, more over the robustness is good in spite of hard clipping.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.66-71
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• 2002

In Generally, a imbedding and extracting is good as watermark using a random dot image. In this paper, when the autostreogram which has some randomness is used watermark image, distortion rate is low and extraction rate is high. Using this quality, when any logo image is transformed to same image domain randomly, distortion rate is low and extraction rate is high, more over the robustness is good in spite of hard clipping.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.243-248
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• 2004

Automatic fingerprint identification is a process of direction extraction, binarization, thinning, minutiae extraction of fingerprint identification. In this process, binarization after direction extraction affects a process of thinning and minutiae extraction. The fasle binarization is increased the false minutiae extraction rate. In this paper, we proposed more exact minutiae extraction algorithm with more enhanced binarization method, compared with traditional binarization process. We could have more enhanced results by using the direction and the half distance between ridges as the threshold of binarization process. In an experiment, Fingerprint images from NIST DBI are tested and the result shows that the proposed binarization algorithm increases minutiae extraction.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.4
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• pp.370-375
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• 1999

To evaluate the efficacy of antibiotic administration in the impacted mandibular third molar extraction the author investigated 107 patients requiring extraction of the lower third molar who visited at the Department of oral and maxillofacial Surgery, Chosun Dental Hospital and were healthy without medical problems and had no signs and symptoms of infection around the lower third molar. The patients were divided into 4 groups according to the method of antibiotics administration: 13 patients without antibiotics administration(group 1), 30 patients with only intravenous injection of $Cefazoline^{(R)}$ 2.0g 30 minutes before the procedure(group 2), 39 patients with intravenous injection of $Cefazoline^{(R)}$ 2.0g 30 minutes before the procedure and oral administration of follow-up dosages of $Augmentin^{(R)}$ for 1 day(group 3), and 25 patients with intravenous injection of $Cefazoline^{(R)}$ 2.0g 30 minutes before the procedure and oral administration of follow-up dosages of $Augmentin^{(R)}$ for 3 day(group 4). Infection rates after extraction were calculated and compared according to gender, the age of the patients, the level of impaction, and also compared between four groups. The results were as follows. 1. The overall infection rate was 8.4%. 2. The infection rate was higher in male(11.9%) than in female(4.2%), but there were statistically no significant differences between them. 3. Infection rate was lower in patients under age 30(7.2%) than in patients over age 30(12.5%), but there were statistically no significant between them. 4. Infection rate was higher in patients with complete bony impacted tooth(11.1%) than in patients with partial bony impacted tooth(6.5%), but there were statistically no significant differences between them. 5. Infection rate was 7.7% in group 1, 10.0% in group 2, 10.3% in group 3, 4.0% in group 4 and there were statistically no significant differences between groups. In summary, it is more important to extract the impacted lower third molar under aseptic condition and to minimize the injury of tissue if possible than to administer the preventive antibiotics in reducing the infection rate in healthy patients without medical problems who had no signs and symptoms of infection around the lower third molar.