• 소성∙가공
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• 제4권2호
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• pp.151-158
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• 1995

In this study, the width spreads of spring steel including Mn-Cr steel(SUP 9A), Mn-Cr-V steel(SUP 11A), and Si-Cr steel(SAE 9254) and were investigated under different reduction ratios and thickness-width ratios friction coefficients. The experimental results were compared with the theoretical prediction by the Ekelund equation, Geuze equations, etc. The width spreads of the three spring steels were found to be 10-15% larger than mild steel, and the optimal reduction ratio for the spring steel was found in a range from 20 to30%. Among the spring steels, the width spread of Mn-Cr-V steel was measured to be the largest followed by those of Si-Cr steel and Mn-Cr steel. It was found that the width spread increased with friction coefficient, width-thickness ratio and reduction ratio as predicted. However, the theoretical predictions revealed smaller width spread than the experimental results. This finding indicates that the coefficients of the width spread of the theoretical models need to be modified in order to predict the actual behavior of the width spreading of the spring steels. In this study, the coefficients of width spread of the Geuze equation were determined from the experimental results.

• 지능정보연구
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• 제15권4호
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• pp.201-212
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• 2009

확산 스펙트럼 방식 워터마킹 기술은 일반적인 공격에 매우 강인한 알고리즘으로 알려져있으나 시간 축 변형 공격에 대해서 만큼은 취약성을 드러내고 있다. 본 연구에서는 확산 스펙트럼 방식 워터마킹 기술의 장점을 살리면서 시간 축 공격에도 강인한 알고리즘을 제안한다. 시간 축 공격은 오디오 신호의 주파수 성분을 변화시키거나 피치성분은 유지하면서 오디오 신호의 길이를 변화시키는 등의 공격을 포함하고 있다. 확산 스펙트럼 방식에 의해서 삽입된 워터마크를 검출하기 위해서는 시간 축 공격의 비율을 정확히 알아야만 한다는 어려움이 있으며, 그 비율을 알기 위해서는 많은 알고리즘의 처리가 필요하고 현실적으로 구현이 불가능한 등의 어려움이 있다. 본 연구에서는 이러한 문제점을 해결하기 위해서 오디오 신호를 시 불변 영역(time-invariant domain)으로 변환하고, 이 영역에서 확산 스펙트럼 방식의 워터마크를 삽입함으로써 확산 스펙트럼 방식의 장점을 유지하고 시간 축 공격에 대해서도 강인한 알고리즘을 제안하였다. 이를 위해서 오디오 신호에 대해 log scale time axis를 사용하고, log scale time axis 신호를 Fourier 변환함으로써 시 불변 영역을 얻을 수 있었다.

• 한국화재소방학회논문지
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• 제32권1호
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• pp.66-75
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• 2018

랙크 내 설치되는 차단막은 초기 화재확산을 지연시키는데 큰 역할을 담당하고 있으나 소화를 목적으로 설치되는 천장형 스프링클러의 입장에서는 소화수의 원활한 공급에 장애물로서 비춰질 수도 있다. 이에 In-Rack 스프링클러와 차단막을 동시에 적용하는 방법 등이 제시되고 있으나 차단막의 설치조건에 따른 화재확산 지연성능 및 In-Rack 스프링클러에 미치는 영향 등에 관한 연구는 부족한 실정이다. 이에 본 연구에서는 축소모델 화재실험을 통해 차단막의 설치조건에 따른 화재확산 지연성능과 In-Rack 스프링클러에 미치는 영향 등을 분석하였다. 그 결과, 랙크 내에 수평과 수직 차단막을 동시에 설치한 경우, 4배 이상의 화재확산 지연성능이 발휘되는 것을 확인하였으며, 구획화로 인한 구획 내 온도 상승 또한 약 2~3배 가량 높은 것으로 나타나 In-Rack 스프링클러가 조기에 작동될 수 있도록 유도하는 긍정적인 효과 또한 존재하는 것으로 나타났다.

• International Journal of Advanced Culture Technology
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• 제12권1호
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• pp.43-50
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• 2024

Patients with acute respiratory diseases, such as Middle East Respiratory Syndrome (MERS) due to COVID-19, must wear masks, protective clothing, face shields, and gloves to prevent infection during treatment and performance. Even if it is applied to disabled people, families who protect them are severely mentally tired from severe physical fatigue and stress from exposure to high-risk infectious diseases. As such, the spread of infectious diseases such as respiratory diseases has not only caused difficulties in using existing welfare and medical services but also caused various problems throughout the daily life of disabled people due to the prolonged infectious disease, and its scope is gradually expanding. Therefore, it should not be overlooked that disabled people may experience various difficulties, from the spread of infectious diseases such as respiratory diseases to isolation, diagnosis, and treatment, and it is time to actively assess the life changes felt by families caring for disabled people and consider and research to provide adequate services. According to the survey of disabled people is being conducted in the context of the spread of infectious diseases such as respiratory diseases, while research on the spread of infectious diseases such as respiratory diseases is rare for parents with disabilities. There is a need for additional investigation into the characteristics in other areas of everyday life, including the health field, which is deteriorating through prior research. Therefore, through this survey, the purpose of this study is to investigate the life changes of parents with disabilities in the context of the spread of infectious diseases such as respiratory diseases and to compare and analyze them to find out how parents were affected by each type of disability. It will be used as evidence to identify more necessary needs and problems for parents with disabilities in the spread of infectious diseases such as respiratory diseases and to provide more appropriate health care and welfare services in the future.

• 소성∙가공
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• 제20권8호
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• pp.534-539
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• 2011

The production technology is the basic of manufacturing for various materials and components. This technology can influence the quality and productivity of leading export products such as automobile, ship, and electronic device. Besides, the production technology is very useful to apply to other manufacturing fields and has a great ripple effect. However, it is very difficult to make the production technology into standardization and knowledge-based database because the production technology is dependent in hands-on experience. In this study, the knowledge-sharing platform for the molding & forming technology which is a branch of the production technology is introduced. This platform is web-based system and has the knowledge authoring tool technologies storage, semantic database, and web portal service. Therefore, the molding & forming technology can be shared and spread easily by the knowledge-sharing platform.

• Preventive Nutrition and Food Science
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• 제19권3호
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• pp.242-245
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• 2014

The flow behaviors of three thickened fruit juices (orange, apple, and grape juice) prepared with a commercial instant xanthan gum (XG)-based thickener that is marketed in Korea were investigated at different thickener concentrations (1.0%, 1.5%, 2.0%, 2.5%, 3.0%, and 3.5%) and setting times (5 and 30 min) using a rheometer and a line-spread measurement method. The flow distance values measured by the line-spread test (LST) were compared with the apparent viscosity (${\eta}_{a,50}$) values measured with a sophisticated computer-controlled rheometer. The ${\eta}_{a,50}$ values of the juices increased as thickener concentration increased, whereas their flow distances decreased. The ${\eta}_{a,50}$ values at the 30-min setting time were much higher than those at the 5-min setting time, indicating that the setting time before serving or consuming thickened juices can affect viscosity values. Plots comparing ${\eta}_{a,50}$ values to LST flow distances revealed strong exponential relationships between the two measures ($R^2$=0.989 and $R^2$=0.987 for the 5- and 30-min setting times, respectively). These results indicate that the LST can be a suitable instrument for evaluating the viscosity of thickened fruit juices prepared with different XG-based thickener concentrations and setting times for the dysphagia diet.

• Journal of the Korean Wood Science and Technology
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• 제16권1호
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• pp.3-8
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• 1988

This study was carried out to examine the effect of pretreatment of veneer with aluminum sulfate solution for the manufacture of the kapur plywood on the reduction of urea resin spread. The results were as follows: 1. Specific gravities of plywoods made of the kapur veneers ranged from 0.83 to 0.84 and their moisture contents based on air dry weight showed from 10.6% to 11.4%. These met the Korean Industrial Standards. 2. In the case of dry shear strength for the 3rd class plywood, 40% reduction- spread met K S as well as normal urea resin spread. pH of the aluminum sulfate solution gave better result at pH 4.5 and pH 6 than at pH 3. For the manufacture of the 2nd class plywood, hot and cold water-wet shear strength show the best results at the following conditions; such as 20% reduction spread, pH 4.5 of aluminum sulfate solution and all veneer treatment.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.164-167
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• 2003

Profile ring rolling process is simulated by using the general purpose commercial finite element analysis software MSC.Superform Because the deforming region is restricted to the vicinity of the roll gap, only a ring segment spanning the roll gap is analysed in order to save computation time and cost. A profile ring with an external round groove is chosen as an example to be analysed. The rolls with and without groove were analysed to compare the amount of side spread. It is found that the grooves in the rolls reduce the amount of side spread.

• Journal of Information Technology Applications and Management
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• 제22권2호
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• pp.95-112
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• 2015

Spread of internet service had a huge effect on usage and spread of SNS world widely. Variety of the service has increased from human network managing to commerce, education, payment method and so on. Also, it is expanding its service territory to not only PC area but also that of mobile equipment with development of information technology. Spread of use on SNS provides existing corporations the expansion of service area. Late SNS starter companies are advancing in diverse way for attracting users by serving shopping, games and other services with association with SNS. Therefore, analysis on consumers' thought and pattern which analyze users' demand, service's function and contents and other factors in order to reflect on plans and operations of SNS is needed. On this perspective, this research is suggesting properties that are crucially related to sustained usage of SNS and study factors of SNS's characteristics that influence trust and satisfaction on SNS and continuous usage intent of SNS.

• 한국방재학회 논문집
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• 제8권4호
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• pp.75-79
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• 2008

현재는 기술적인 발전을 토대로 정보의 요구수준이 상당부분 증대되었으며 GIS (Geographic Information System)분야 또한 더 많은 정보를 보다 신속하고 정확하게 처리 되어지고 있다. 특히 산불에 있어서는 산불발생시 공간적으로 넓은 지역을 신속히 분석하여 진화의 기초자료로 활용함으로써 환경적, 경제적, 인명적 피해를 최소화하고 대피경로, 확산경로 및 진화자원의 효율적 배치를 결정하는데 필수적이다. 이러한 산불확산에 영향을 미치는 인자 중에서 경사에 따른 산불확산속도를 규명하기 위하여 경사 및 경사방향에 따른 실험을 실시하였다. 실험결과 상향경사의 경우 경사가 증가할수록 시간이 감소하고, 하향경사에서는 증가하는 경향을 나타내었다. 실험결과 값을 토대로 상향경사는 (+), 하향경사는 (-)로 구분하여 경사에 따른 산불확산속도를 계산하였으며, 이러한 결과는 정확한 산불확산예측을 하는데 기여함으로써 효과적인 산불진화에 도움을 줄 수 있을 것으로 판단된다.