• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.3
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• pp.1-21
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• 1999

화장품, 의료용, 가정용품 및 공업용제품에까지 광범위한 용도로 사용량이 많은 중요한 비이온 계면활성제의 종류 중에서 polyoxyethylene(POE) 부가형 계면활성제의 경우 그 부가몰수에 따라 특성이 달라지고 용도가 다르게 사용된다. 이때 부가된 분자들의 분자량이 크고 분포를 이루는 혼합물이기 때문에 분석이 매우 어렵다. 따라서 MALDI-TOF/MS 방법을 이용하여 이들의 분자량과 그 분포를 측정함으로써 쉽고 빠르게 측정할 수 있는 새로운 방법을 개발하고자 하였다. 이 논문에서는 화장품에 주로 사용되는 비이온 계면활성제를 선택하여 MALDI-TOF/AfS를 측정하여 스펙트럼으로부터 분자량 분포와 POE부가정도를 측정할 수 있었다. 그리고 이 조건을 적용하여 시중에 판매되는 제품에서 추출된 비이온 계면활성제의 MALDI-TOF/MS 스펙트럼으로부터 분자량 분포와 POE 부가 정도를 확인 할 수 있었다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.3
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• pp.23-46
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• 1999

LC/MS는 HPLC의 분리능과 질량분석기의 화합물의 확인 능력을 결합시킨 기기이다. 여기서 사용되는 이온화 방법은 GCJMS에서 사용되어지는 전자이온화법(electron ionization, EI)이나, 화학이온화법(chemical ionization, CI)은 부적당하기 때문에 최근 개발되어진 연성 이온화법의 대표적인 고속원자폭격식(Fast atom bombardment, FAB)이나 전기분무이온화식 (electrospray ionization, ESI) 등이 사용되고 있다. 이중 전기분무이온화법은 고속원자폭격법에서 사용되는 매트릭스를 사용하지 않기 때문에 매트릭스 이온의 부재로 인한 낮은 바탕 신호, 오래 지속되면서 안정된 초기 이온 전류, 샘플링의 용이성, HPLC와의 더 좋은 호환성 등의 장점을 제공한다. 이러한 전기분무이온화 방법은 극성이 매우 크거나 휘발성이 낮은 물질로 보통의 EI나 CI 이온화 방법으로 분석이 어려운 물질들을 분석할 수 있다. 또한 열에 불안정하거나 분자의 분자량이 다른 단백질 등의 분석도 가능하다. 이러한 LC/ESI/MS 방법을 이용하여 열에 불안정하고 극성이면서 분자량이 커서 GC/MS 펄의 분석이 어려운 기능성 화장품 원료로 주목받고 있고 생체에 존재하는 지질 성분으로 알려진 레시틴과 세라마이드의 분석이 가능함을 소개하고 분리와 동시에 그 분자량과 구조에 대한 정보를 빠르게 얻을 수 있음을 소개하였다.

• Communications of Mathematical Education
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• v.20 no.4 s.28
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• pp.561-574
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• 2006

Mathematical creativity has been confused with general creativity or mathematical problem solving ability in many studies. Also, it is considered as a special talent that only a few mathematicians and gifted students could possess. However, this paper revisited the mathematical creativity from a mathematics educator's point of view and attempted to redefine its definition. This paper proposes a model of creativity in school mathematics. It also proposes that the basis for mathematical creativity is in the understanding of basic mathematical concept and structure.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.247-249
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• 2001

최근 VOD(Video On Demand)나 AOD(Audio On demand) 서비스가 급증하면서 멀티미디어 스트리밍 기술에 대한 관심이 커지고 있다. 기존의 스트리밍 서비스는 정적으로 멀티미디어를 전송하므로 네트워크 환경의 대역폭(bandwidth) 변화에 대처하는데 한계가 있다. 이러한 문제점을 해결하기 위하여 본 논문에서는 실시간 스트리밍 서비스(RTSS; Real Time Streaming Service) 시스템을 제안한다. RTSS 시스템은 동화상의 끊김없는 전송보장을 위해 미디어 스케일링 방식을 사용하고, 대역폭 변화에 능동적으로 대처할 수 있도록 동적인 멀티미디어 전송을 이용한다. 기존의 스트리밍 서비스의 버퍼링 방식의 단점을 해결하기 위하여 본 논문에서는 프레임 조정방식과 화질 조정방식을 동시에 채택하여 적용함으로써 고화질이 보장되는 전송환경과 느린 회선에서도 끊김없이 안정적인 스트리밍 서비스를 제공받을수 있도록 한다.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.91-94
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• 2003

A DC railway system has low feeder voltage, The fault current can be smaller than the current of load starting. So it is important to discriminate between the small fault current and the load starting current. The load starting current increases step by step but the fault current increases all at once. So the type of ${\Delta}I$ relay(50F) was developed using the different characteristics between the load starting current and the fault current. As for the load starting current, the time constant of load current at each step is much smaller than that of the fault current. First, to detect faults in DC railway systems, an algorithm using the time constant calculated by the method of least squares is presented in this paper. Secondly, to compose a protection scheme for DC railway systems is presented in this paper.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.2
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• pp.245-256
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• 2000

The purpose of this study was to examine the influence of stress, body satisfaction, academic record, and demographic variables on the normative conformity toward clothing and clothing satisfaction of high school students. The subjects were 389 high school students(boys: 169, girls: 220) in Seoul, Korea. The normative conformity toward clothing measured by the degree of wearing of unsuitable clothes for school clothing and private clothing norm of students. The school clothing was influenced by allowance, gender, stress of home life, academic record(-), mother's education(R2=.270). The private clothes was influenced by allowance, gender, stress of home life, body satisfaction, and geographical region(R2=.200). The clothing satisfaction was influenced by body satisfaction, gender, allowance, geographical region, and stress of home life(-)(R2=.325). The present findings provide that stress of home life, gender, and allowance had effect on the normative conformity toward clothing, and the higher the stress of home life, the lower the degree of clothing satisfaction.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.176-181
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• 2008

This study aims at providing developmental process for art and cultural space putting into an alternative in pursue of territorial arts and applicable tourist resources by bridging connectivity between arts and tourism. It overviews art promotional policies by a variety of associations since the end of 1990s, focusing on studios for art creation, while attempting to develop effective and practical operational process by analytically identifying in detail various touch points possibly occurrently in the field of arts and culture.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.3
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• pp.5-22
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• 1998

This study compared whether there are significant differences of searching characteristics between the subject specialists and professional searchers in education in terms of internet search engines. The major findings and conclusions from the study are as follows. Subject specialists used more search terms and Boolean operators and spent more times on the computers than professional searchers. However, professional searchers retrieved more relevant documents and had higher precision ratios than subject specialists.

• Journal of the Korean Society for Library and Information Science
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• v.31 no.2
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• pp.177-197
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• 1997

The study measured whether two search engines retrieve different Web documents for 6 queries. Two different search engines, Alta Vista in terms of keyword search engines and Yahoo in terms of subject directory engines were measured using as criteria, total number of documents retrieved, total number of relevant documents retrieved, recall and precision ratios. In addition, Alta Vista was suitable for specific and technical terms, while Yahoo was effective for general and plain terms. However, more elaborate research needs to be tested in terms of query characteristics.

• Journal of Korean Biological Nursing Science
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• v.25 no.1
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• pp.55-62
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• 2023

Purpose: Tinnitus, which is often described as the conscious awareness of a sound without an external auditory stimulus, is one of the most common symptoms in the general population. This study aimed to explore the experiences of individuals living with tinnitus. Methods: In this qualitative exploratory study, data were collected from November 2017 to January 2018 through in-depth individual interviews with 11 tinnitus patients. Verbatim transcripts and field notes were analyzed using content analysis. Results: The extracted content was classified into three core categories of tinnitus experiences: "suffering from constant sound," "being imprisoned surrounded by persistent noise," and "efforts to overcome." Conclusion: This study shows that tinnitus had a severe negative impact on patients' lives. The finding will help healthcare providers understand their patients more deeply.