폐주불사를 혼입한 콘크리트의 내구성에 관한 연구

김태경,박정호,이정호,이주형,박제선,김연경,윤경구 강원대학교 석재복합신소재제품연구센터 1998 석재연 논문집 Vol.3 No.-

콘크리트 구조물은 자연적인 혹은 인위적인 온도의 상승, 강하로 인하여 동결-융해 작용을 받게 되어 구조물의 성능저하를 야기시킨다. 현대에 들어서면서 콘크리트의 내구특성을 파악하기 위한 연구적 요구가 증가되고 있다. 따라서 폐주물사 콘크리트를 실제 구조물에 적용하기 위해서는 내구특성에 대한 연구가 반드시 이루어져야 한다. 폐주물사를 혼입한 콘크리트의 내구특성을 파악하기 위한 동결-융해 실험은 폐주물사의 잔골재 치환율, 물-시멘트비, AE제 사용 여부를 주요 변수로 하여 실시하였다. 원형공시체를 제작하여, 동결-융해 시험기에 넣어 -18∼4℃로 급속 동결-융해를 진행시키면서 매 23싸이클마다 동탄성계수를 측정하였다. 실험결과 AE제를 첨가했을 때 물-시멘트비가 적을수록, 폐주물사의 치환율이 클수록 전반적으로 강도가 증가하는 것으로 나타났으며, 물-시멘트비가 증가함에 따라, AE제를 사용한 콘크리트가 동결-융해 저항성이 증가하는 것으로 나타났다. 특히 폐주물사 치환율이 50%일 때가 동결-융해 저항성이 가장 좋은 것으로 나타났으며 그 다음으로 25, 0% 순으로 저항성이 좋은 것으로 나타났다. 따라서 폐주물사 콘크리트가 내구성이 우수한 것으로 나타나 폐주물사를 콘크리트에 재활용 할 수 있는 것으로 나타났다. Concrete structures has been deteriorated by the freezing and thawing due to temperature gap. This study was conducted to evaluate durability of concrete which are increasingly demanded recently. Therefore the research of durability must be executed for application of waste foundry sand concrete real structures. Concrete durability properties incorporating waste foundry sand was performed with the variable of W/C ratio, Sand/Waste foundry sand ratio and Air entrainment-Non air entrainment. Cylinder specimens were made and subjected to freezing and thawing cycle at -18℃ and 4℃. Dynamic modulus of elasticity were evaluated as F/T cycle increase. The results show that strength of concrete is increased the W/C ratio decrease, the Sand/Waste foundry sand ratio increase when the concrete contains AE agent and decreasing W/C ratio and AE concrete makes improved resistance of freezing and thawing improved. Especially, resistance of freezing and thawing is improved by Fine aggregate/Waste foundry sand ratio which is 50%, 25%, 0% in a row. Therefore it is turn out the waste foundry sand could be applied to concrete from the experiment.

링 예약 알고리즘을 이용한 ATM 스위치

주우석,박경희,유승열,최병석 明知大學校 産業技術硏究所 1995 産業技術硏究所論文集 Vol.14 No.-

We propose a new architecture of multicast ATM switch which has input and output buffers and uses Multicast Ring Reservation Algorithm to resolve output port contention. This new algorithm eliminates internal cell loss due to contention, and reduces the hardware complexity. We can dynamically control the number of cells routed to a specific output port during one cell time with this contention resolution algorithm. The computer simulation is performed under bursty traffic condition to show the performance of this proposed multicast ATM switch.

초등학생 치아우식경험과 자녀 어머니의 구강위생에 관한 연구

주경삼 한국위생과학회 2002 한국위생과학회지 Vol.8 No.2

The purpose of this study is to assess how mothers' oral health hygienic, practices and on their children's dental health status. In addition, to evaluate the relative effect on the children's oral status, mothers' hygienic and children's tooth morphology will be compared. Children of grade 1 and 2 were selected at west elementary school in gyeongsan city. The total number was 270. The mothers who responded the questionnaire of them were 220 through the self-administered method. Datas were collected by oral examination on children and questionnaire survey on their mothers from July to November in 2002. Independent variables were mothers' oral hygienic and children's tooth morphology.

해양관광개발을 위한 어항 활용방안에 관한 연구

김도경,손석범,정주석 경희대학교 디자인연구원 2005 예술· 디자인학연구 Vol.8 No.1

Ocean tourism is rising as a new leisure activity pattern thanks to increased income level and leisure time. Korea is surrounded by the sea on all sides but one, however, we are in beginning stage for the development of ocean tourism resource. In order to meet the demand for ocean tourism that increases yearly, a facility is needed that can satisfy various activities and desires at ocean. Especially, it would be effective to develop fishing port into ocean tourism site, as it's equipped with natural view, cultural resource and industrial facility regardless the role of fisheries base. This study, therefore, will investigate on the function and value of fishing port, and review on the advanced foreign country's cases in order to grope for utilizing fishing ports scattered in Korea into ocean tourism resource.

SCM을 위한 ATP 모델링에 관한 연구

진동주,양광모,박주식,강경식 明知大學校 産業技術硏究所 2002 産業技術硏究所論文集 Vol.21 No.-

최근 기업활동의 자재구매, 제조, 보관 및 운송, 유통/판매까지 포함한 공급체인 전체에 대해 통합관리가 중요한 과제로 부각되고 있다. 현대의 고객들은 제품이나 납기, 품질과 같은 부문에서 높은 서비스를 받고 싶어한다. 이에 따라 오늘 날의 대부분의 기업들은 고도의 기술을 요하는 정보시스템의 도입과, POS, Data Mining 등과 같은 기술들을 이용하고 고객의 요구사항들을 적시, 적소에서 파악하여 고객이 요구하는 상품과 서비스를 공급하기 위하여 최선의 노력을 다하고 있다. 최초의 공급자로부터 소비자까지 상품이 전달되는 과정 중에서 재고와 물류기용은 모든 비용의 대부분을 차지하고 있다. 이에 대한 비용을 줄이려고 하는 것이 공급체인관리(SCM)의 기본적인 목적이라 하겠다. 이에 본 논문에서는 공급체인관리(SCM)에 대한 개념과 배경, 필요성 등을 정리하고 주요 SCM solution에서 제공하는 기능 및 사용된 방법론을 분석하여 이를 바탕으로 주문 접수 시 주문물량의 가능납기를 산정하기 위한 입력데이터, 고려요소, 연산절차 등을 포함한 ATP(Available to Promise) 모델을 제시한다.

도시 외부공간 중 건물들의 시각적 물리량, 복잡도, 선호도 분석에 관한 연구

김도경,서주환,최재혁,류홍선 경희대학교 부설 디자인연구원 1999 예술· 디자인학연구 Vol.2 No.1

Purpose of this study is to prove the relationship among the amount of surface area, the visual complex and the visual preference of Buildings in the urban space using computer simulation. It has the same results as the previous studies. In the urban Environment, especially about buildings, basic data which make possible to apply computer simulation at environment analysis will be supplied. In order to investigate the relationship between the amount of surface area and the visual complex, the visual complex and the visual preference, graphic simulation has been proceeded. Graphic factors of simulation photos are determined on the point of shape and colors(about buildings, land, and sky) The result of the relationship of the visual complex and the visual preference, and the amount of surface area and the visual preference are found to be inverse U-shape, and the result of the relationship of the amount of surface area and the visual complex is proved by the result of regression. So the same result has been obtained in computer simulation.

라덱스 혼입률에 따른 철근콘크리트의 휨파괴 거동특성

정원경,김동호,이주형,임홍범,윤경구 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

Reinforced concrete(R/C) is commonly used to structures because they have many merits that compressive strength, economy and so on. However, reinforced concrete has a crack at the tensile section which is due to the relatively lower tensile strength than its compressive strength. Latex modified concrete(LMC) has higher tensile and flexural strength than the ordinary portland cement, due to the interconnections of hydrated cement and aggregates by a film of latex particles. The purpose of this study was to investigate the flexural behavior of reinforced concrete beam with latex modified concrete, having the main experimental variables such as concrete types(ordinary portland cement concrete, latex modified concrete), latex contents(0%, 15%), flexural steel ratios(0.012, 0.0235), and with/without shear reinforcement. The beam of LMC showed considerably higher initial cracking loads and ductility than that of OPC, but, similar to ultimate strength and deflection. This might be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic, and colloidal properties of the latexes resulting in reduced water evaporation. The beam with latex modified concrete could be adopted at field for controlling and reducing the tensile crack due to its higher tensile strength.

라텍스개질 콘크리트의 물-시멘트비에 따른 건조수축 특성

정원경,김성환,김동호,이주형,이봉학 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

Drying shrinkage cracking which may be caused by the relatively large specific suface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. LMC and RSLMC were studied for field applications very actively in terms of strength and durability in Korea. However, there were no considerations in drying shrinkage. Therefore, the purpose of this dissertation was to study the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), water-cement ratios and curing days at a same controlled environment of 60% of relative humidity and 20℃ of temperature. The drying shrinkage for specimens was measured with a digital dial gauge of Demec. The test results showed that the drying shrinkage of LMC and RSLMC were considerably lower with low water-cement ratio, respectively. This might be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic, and colloidal properties of the latexes resulting in reduced water evaporation.

한국 보험산업의 발전과 규제완화 방향

李炅周 홍익대학교 경제연구소 1997 經濟硏究 Vol.12 No.-

라텍스 개질 콘크리트의 건조수축특성

윤경구,홍창우,이주형 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

Drying shrinkage cracking which may be caused by the relatively large specific surface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. Therefore, the purpose of this dissertation was to study the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), latex contents(0, 5, 10, 15, 20%), W-C ratios, and curing days at a same controlled environment of 60% of relative humidity and 20℃ of temperature. Test results revealed that the drying shrinkage of latex modified concrete(LMC), rapid-setting cement latex modified concrete(RSLMC) was considerably lower than that of ordinary portland cement concrete(OPC), rapid-setting cement concrete(RSC), respectively. This may be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic and colloidal properties of the latexes, resulting in reduced water evaporation.