• Archives of design research
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• v.20
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• pp.61-72
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• 1997

This study aims to promote understanding level for mathematical model, to improve methods and necessity of application in the process of product design and also to promote approaching and applying methods as a guideline for beginners. For the procedure and method of study first, it was emphasized by linking method and necessity of scientific analysis and a quality of product design and design process. Next, the corresponding relations between mathematical model and design probelem was desciebed, the mathematical model was examinated appeying process of product design. Lastly, approaching and applying methods for beginners was presented based on the discribed studied contents. As the result of the study, some points are by a result or problem : frist, the point that mathematical model is useful to grasp the design problems which various elements are complicately involved quantitatively and structurally, and its necessity can be especially utilized as a tool to justify and convince the convince the conclusion of the designer himself to the persons concerned. Second, the point that in order to apply mathematical model to the design process skillfully, first of all, the substance of all mathematical models which can be applid, and it is not easy to command in perfect method without using computer. Third, the point that since there are many kindsof mathematical models used is mathematical modeland the models which can be applidied to solve design problems differ in accordance with the design types and design process, its applying method can be presented as one kind of standardization or concretely. Fourth the point that in case of approaching mathematical model for the first time, it can start to select model corresponding with design type by stage of design process bassed on understanding for some mathematical knowledge and computer program.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.233-240
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• 2014

An in vitro study on cariogenic potential of four over-the-counter nutritional supplements for children was performed. The experimental groups were four over-the-counter nutritional supplements. The positive control group was 10% sucrose solution (S), and the negative control group was artificial saliva (T). The pH of each group, the buffering capacities, acid production, the microhardness changes of the bovine teeth specimens were measured. The pH of all experimental groups were lower than critical pH 5.5 where enamel demineralization starts. The buffering capacity of the Hama Vitamin Pharm (Hamsoa Pharm Co., Korea) was highest, and the Smart Chewable Vitamin A (JW Pharm Co., Korea) had the lowest buffering capacity. The reduction rates of the pH of the experimental groups were significantly higher than that of the negative control group (p < 0.05). The microhardness of enamel of all experimental groups and the positive control group significantly decreased. In contrast, the microhardness of enamel of the negative control group significantly increased after experiment (p < 0.05). The reduction rate of the microhardness of enamel of the Hama Vitamin Pharm (Hamsoa Pharm Co., Korea) was significantly higher and Hikid Plus (Sanga Pharm Co., Korea) was significantly lower than the other experimental groups.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.183-184
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• 2010

In this study, it suggested evaluation method of carbonation about crack to occur in an early age. And it compared penetration depth of carbonation with crack size.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.281-282
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• 2010

In this study, it aimed to analyze relation of stress and strain strain for concrete with various under-loading level at elevated temperature.

• Journal of the KSME
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• v.22 no.3
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• pp.203-213
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• 1982

이재결합재의 피로시험에서 나타나는 피로균열성정거동은, 역시 균열선단이 결합경계의 근방에 있거나 경계상에 있을 때의 것이 균질재료에서의, 거동과 비교.검토되어야겠다. 이재결합재를 여기에서는 탄성계수 E 값이 동일(또는 근접)한 이재간의 결합재와, E 값이 현저히 다른 이재 간의 결합재로 나누어 그 피로시험예를 검토해 나가기로 하겠다. 또한 전술한 바와 같이 이재 결합재에 의한 피로시험 그 자체의 난전으로 말미암아 파괴역학적으로 해석된 이재결합재피로 균열거동연구보고가 극히 부진함에 비추어 여기에서는 주로 필자가 발효한 연구보고들을 바탕 으로 해서 검토해 나가기로 하겠다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.243-245
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• 1998

미래의 셀룰라 이동통신망은 멀티미디어 데이터 서빗를 제공하기 위해서 높은 대역폭이 필요하기 때문에 셀의 크기가 수십 미터 내오인 피코 실(pico cell)로 구성되는 피코 셀 망이 될 것이다. 이와 같은 피코 셀룰라 망에서는 이동통신자의 우치 변화에 따른 handoff 처리 회수가 상대적으로 증가하므로, handoff 처리로 인한 망부하가 늘어났고, handoff처리 지연으로 인하여 사용자는 중단없는 연결서비스 (seamless connection service)를 받지 못할 수도 있다. 본 논문은 VT-CSMA방식을 응용한 기법을 새로운 handoff방식으로 제안한다. 이 기법은 handoff에서 사용하고 delay time virtual clock 과 real clock 의 2개의 clock을 갖도록 함으로써, 빠른 속도로 이동하는 호는 느린 속도로 이동하는 호보다 상대적으로 짧은 시간 내에 handoff가 처리 되도록 한다. 모의 실험 결과는 VT-CSMA기법을 응용한 새로운 방식이 기존 CDMA 방식에서 drop되는 호를 많이 줄이는 효과가 있음을 보인다.

• 한국약용작물학회:학술대회논문집
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• 2011.04a
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• pp.352-353
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• 2011

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.33-33
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• 1998

2차 유동 분사에 의한 추력 방향 제어 방법은 기존의 기계적인 장치를 이용한 방향제어 방법에 비해 부가적인 복잡한 기계적 작동장치와 이에 따른 무게의 증가를 배제할 수 있다. 본 연구에서는 전산 유동해석을 이용하여 2차원 초음속 수축-행창 노즐 유동에 2차 유동을 분사하여, 2차 유동의 분사우치 및 분사 유량 및 분사 각도 등이 추력의 방향 및 크기에 미치는 영향을 밝혀 이들 상호간의 상관관계를 구하여 추력 방향 제어를 위한 최적의 2차 분사 조건을 제시하였다. 유동 해석 견과 2차 유동의 분사 위치는 생성된 경사 충격파가 노즐 출구까지 분포되는 지점이 최대 전향각과 횡추력을 가지는 분사 위치임을 알 수 있었다

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.209-210
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• 2010

In this study, present $CO_2$ penetration coefficient evaluation method toward finishing materials for reducing carbonation and urethane and acrylic is to compare the $CO_2$ penetration coefficient.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.427-428
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• 2010

Recently, building structure damage and number of lives lost by bomb terror is increasing. Therefore, in this study, it is aimed to present basic data for blast resistance performance of concrete member with intermediate space by fiber reinforced mortar panel by explosion test.