• 한국안전학회지
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• 제18권3호
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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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• 제34권1호
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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.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1991년도 추계종합학술발표회논문집
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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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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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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.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1995년도 춘계학술발표회 초록집
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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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.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2002년도 추계공동학술대회 정보환경 변화에 따른 신정보기술 패러다임
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• pp.66-71
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• 2002

삽입하려는 암호영상이 원본 전체 이미지 내에 랜덤하게 분포할수록 삽입과 추출성능이 좋아지는데 본 논문에서는 랜덤성이 우수한 오토스테레오그램을 삽입암호 영상으로 사용하여 워터마크 하였을 때 복원과 추출성능이 양호함을 알아보았고 이를 이용하여 로고영상을 워터마크하려는 영상의 전 영역에 랜덤하게 고루 분포하게하여 워터마크한 후 역으로 변환하여 로고를 찾았다. 영상이 많이 손상되었을 때도 추출된 로고가 육안으로 식별할 수 있을 정도로 견고성이 우수함을 알아보았다.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2002년도 추계공동학술대회
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• pp.66-71
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• 2002

삽입하려는 암호영상이 원본 전체 이미지 내에 랜덤하게 분포할수록 삽입과 추출성능이 좋아지는데 본 논문에서는 랜덤성이 우수한 오토스테레오그램을 삽입암호 영상으로 사용하여 워터마크 하였을 때 복원과 추출성능이 양호함을 알아보았고 이를 이용하여 로고영상을 워터마크 하려는 영상의 전 영역에 랜덤하게 고루 분포하게 하여 워터마크 한 후 역으로 변환하여 로고를 찾았다. 영상이 많이 손상되었을 때도 추출된 로고가 육안으로 식별할 수 있을 정도로 견고성이 우수함을 알아보았다.

• 융합신호처리학회논문지
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• 제5권4호
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• pp.243-248
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• 2004

자동 지문 인식 과정은 지문의 방향성 추출, 이진화, 세선화, 특징점(끝점, 분기점)추출의 과정을 거치게 되며, 여기서 방향성 추출 이후 이진화는 세선화와 특징점(끝점, 분기점)추출 과정에 많은 영향을 미친다. 잘못된 이진화는 특징점의 오추출율을 증가시킨다. 본 논문에서는 기존의 이진화 과정과 비교하여 개선된 이진화 방법으로 더욱 높은 정확도의 특징점 추출 알고리즘을 제안한다. 이진화 과정을 수행할 때 문제가 되는 임계값을 지문의 방향성과 융선간의 반주기를 이용하여 비교 대상 영역의 밝기를 임계값으로 적용함으로써 더욱 뛰어난 이진화를 수행하여 지문인식의 향상된 처리 과정을 수행할 수 있다. NIST DBI의 지문화상에 적용한 결과 제안하는 이진화 알고리즘이 특징점 추출을 향상 시켰음을 나타내고 있다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권4호
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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.