• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.95-102
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• 2011

This paper presents a Driving Risk Model (DRM) based on driving speed choices using an Ordered Response Probit (ORP) model. The DRM is conceptualized based on the relation between speed deviation and the occurrence of crashes found by Solomon. The impacts of various driving risk factors are revealed by applying the DRM to evaluate the effectiveness of In-Vehicle Traffic Warning Information (IVTWI) in expressway driving. Regarding driving risk, the results show that: (1) the risk is lower among male drivers, those with more driving experience and those with less accident history, (2) the risk is higher when driving takes place on wet road surface, in the afternoon, and under conditions of low traffic volume, and (3) the risk is also higher on both downgraded and long curve sections. Additionally, the results provide evidence that provision of IVTWI can decrease the driving risk. The proposed DRM provides a solution for assessing the traffic safety impacts of countermeasures on roadways when there is a shortage of traffic accidents data.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.551-553
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• 2000

VLSI 기술의 발전에 따라 프로세서의 속도는 빠르게 증가하고 있는 반면 메모리의 속도는 이를 뒷받침하지 못하여 속도의 차이를 줄이기 위해 캐쉬(cache) 메모리를 사용하고 있다. 캐쉬가 알고리즘의 실행시간에 미치는 영향이 점점 더 커지고 있으나 이제까지 개발된 대부분의 알고리즘들은 이러한 캐쉬의 중요성을 고려하지 않고 개발되었다. 본 논문에서는 캐쉬 효과를 고려한 확장된 이진 탐색 트리 알고리즘에 관해 연구하였고, 실험을 통하여 기존의 이진 탐색 트리와 제안된 알고리즘의 성능을 비교하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.580-582
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• 2001

VLSI 기술의 발전에 따라 프로세서의 속도는 빠르게 증가하고 있는 반면 메모리의 속도는 이를 뒷받침하지 못하여 속도의 차이를 줄이기 위해 캐쉬(cache) 메모리를 사용하고 있다. 캐쉬가 알고리즘의 실행시간에 미치는 영향이 점점 더 커지고 있으나 이제가지 개발된 대부분의 알고리즘들은 이러한 캐쉬의 중요성을 고려하지 않고 개발되었다. 본 논문에서는 캐쉬 효과를 고려한 확장된 Pairing Heap 알고리즘에 관해 연구하였고, 실험을 통하여 기존의 Pairing Heap 알고리즘과 제안된 알고리즘의 성능을 비교하였다.

• Journal of the Korean Chemical Society
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• v.52 no.3
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• pp.217-222
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• 2008

We investigate the kinetics of diffusion-influenced catalytic reactions occurring in small reaction volume. From a simple exact model study, we find that the reaction rate coefficient decreases with the size of reaction volume. The explicit expression for the average reaction rate constant is presented, which can be regarded as a generalization of well-known Collins-Kimball rate constant into the reactions occurring in a small reaction volume. It turns out that the traditional diffusion influenced reaction dynamics is followed by a single exponential relaxation phase with a rate constant dependent on the reaction volume for the catalytic reactions occurring in small reaction volumes.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.743-747
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• 1994

The catalytic effects of carboxylic acid and dibutyltin dilaurate(DBTL) on the curing rate of acrylic polyol with isocyanate prepolymer were investigated. In this work reaction of a biuret type aliphatic isocyanate with acrylic polyol follows the second order reaction in the thin film state. Carboxylic acid of acrylic polyol has a strong catalytic effect on the isocyanate groups and influences greatly on curing rate, also DBTL is more effective catalysis on acrylic polyol without carboxylic acid than with carboxylic acid.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.276-281
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• 1995

마모씨일과 발란스디스크에서의 로마킨효과가 3600rpm에서 운전되는 14단 터빈펌프의 동특성에 미치는 영향을 고찰한 결과 다음과 같은 결론을 얻을 수 있었다. 1. 14단 터빈펌프 시제품 해석을 위한 유한요소 모델링 및 해석결과는 실험적 모드해석을 통하여 5% 이내의 오차로 검증되었다. 2. 마모링 및 밸런스 디스크의 로마킨효과를 고려하였을 때 시제품 펌프의 위험속도는 그렇지 않았을 때에 비하여 1차의 경우 약 50% 상승하나 고차의 경우는 그 영향이 미미하였다. 그런데 1차 위험속도가 운전속도와 밀접한 관련이 있으므로 설계시 로마킨효과는 반드시 고려되어야 한다. 3. 마모링 및 밸런스디스크의 설계변경에 의하여 시제품 펌프의 강성을 변화시킬 경우 위험속도가 크게 변화하는 것으로 나타났다. 이를 이용하면 펌프의 심각한 구조변경 없이도 씨일의 적절한 설계에 의하여 임펠러 깃등의 고조화성분을 포함한 유해한 진동을 회피하는 동특성 설계가 가능하다. 향후 계속 연구사업으로서 씨일의 동특성 해석코드 개발 및 Wet Test를 통하여 본 연구결과를 검증하고 그 결과를 다단 터빈 펌프의 동특성 설게에 적용하여 고압 다단 터빈 펌프의 독자적 개발에 활용코자 한다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.1
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• pp.18-30
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• 1993

A numerical analysis has been carried out on the Czochralski flow fields when uniform and nonuniform magnetic fields are applied. Czochralski flow fields are governed by buoyancy forces, thermocapillarity, centrifugal forces, and applied magneic fields. In this analysis, pressure and three components of velocity vectors are obtained, and circumferential electrical currents are calculated. When a uniform magnetic field is applied, all the velocity components are decreased and the circumferential electric currents near the crystal surface are increased as the magnetic field intensity is increased. In the case of a nonuniform field, the flows in a meridional plane are suppressed and the circumferential velocity is increased as the non uniformity is increased. The understanding on the Czochralski flow fields under the influence of magnetic fields can lead to the study on the behavior of the concentration of the solute and impurities.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.223-226
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• 1982

The aim of the present study was to assess the oxygen transfer rate and oxygen uptake rate in antibiotic fermentation. As a model study, cultures of Streptomyces kanamyceticus in a complex medium were analyzed to evaluate the oxygen transfer and uptake rates using oxygen balance technique. Quantitative evidence for the effect of oxygen transfer rate on the volumetric antibiotic production was clearly demonstrated. The oxygen uptake rates and the specific oxygen requirements were significantly changed with culture time. Those phenomena were indicative of biological turnover in the antibiotic fermentation.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.417-421
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• 2014

We conducted this study to verify effect of applying musical rhythm during the cardiopulmonary resuscitation(CPR) education. From June to October, 2013, we recruited participants of CPR education among mem's high school students. We divided total 57 participants to 2 groups. For experimental group we use musical rhythm during cardiac compression practice to assist adequate cardiac compression rate and for control group do not apply musical rhythm. The group with musical rhythm show more adequate compression rate(16.4sec) than non-rhythmic group(14.4sec). 90% of rhythmic group keep adequate compression rate, but only 44% of non-rhythmic group keep adequate rate. In conclusion, applying musical rhythm to CPR education is more effective to keep correct cardiac compression rate.

• The Journal of the Korea Contents Association
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• v.20 no.9
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• pp.430-438
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• 2020

Many local governments are reducing speed limits according to the "Safe Speed 5030" policy implemented by the government to reduce traffic accident deaths. In the urban road sections in many metropolitan cities where speed limit reduction is applied as a pilot project, the decrease effect of the traffic accident number and death count is shown; however, no study of the effect analysis on the road sections of medium and small cities (basic local government unit) is found. Therefore, this study investigated the travel speed, number of traffic accidents, and death count before and after the implementation of speed limit reduction, targeting some urban road sections in Pyeongtaek city and some provincial road sections in Icheon city among basic local governments, namely among medium and small cities in Seoul Metropolitan Area.