• 한국지반공학회논문집
• /
• 제23권5호
• /
• pp.153-162
• /
• 2007

치환공법을 적용하여 연약지반 상에 시공되는 보강토 옹벽에 대해 연약지반의 두께 및 강성, 치환깊이와 옹벽높이의 변화에 따른 옹벽의 거동을 연약지반 압밀현상과 시공단계를 함께 고려하는 유한요소해석으로 검토하였다. 옹벽의 거동은 벽체에 발생하는 변위와 침하량, 옹벽 기초지반에 발생하는 전단변형율로 표현하였다. 거동에 따른 옹벽의 안정성은 변위와 전단변형율의 한계값을 문헌연구로부터 정하고 이를 기준으로 평가하였다. 해석결과로부터, 옹벽의 거동은 연약지반 두께(t)와 강성, 치환깊이(d), 옹벽높이(h)의 변화에 따라 모두 영향을 받지만, 특히 d와 h의 변화에 민감한 것을 규명하였다. 또한, 옹벽의 안정성 유지를 위해 요구되는 d/h 값은 t와 h의 변화에 대하여 크게 영향을 받지 않음을 보였다. 이러한 결과로부터 연약지반 상 보강토 시공 구간 내에서 옹벽 높이가 변화하지만 그 변화정도가 극심하지 않은 경우에, 적정 치환깊이를 d/h로 나타낸 일률적인 값으로 제안할 수 있다는 결론을 얻었다.

• 대한토목학회논문집
• /
• 제34권5호
• /
• pp.1455-1461
• /
• 2014

본 연구에서는 2011년 5월, 6월, 7월에 덕유산 덕곡제에서 관측된 플럭스자료를 이용하여 에디공분산방법으로부터 증발산량을 측정하는 경우 발생할 수 있는 연직방향 풍속의 이상치 판별 및 대체에 대한 통계적 분석을 실시하였다. 연직방향 풍속의 이상치를 파악하기 위해 적용된 통계분석방법은 사분위수를 바탕으로 상자그림(boxplot)의 분석결과 중에 이상치를 판별하기 위한 interquartile range (IQR)을 적용하여 이상치를 탐색하였다. 또한 삭제하거나 평균값으로 대체하는 방법을 통하여 보완된 연직방향 풍속자료를 이용하여 증발산량을 측정하였으며, 이를 보완전의 증발산량과 비교분석하였다. 비교분석한 결과에 의하면 이상치를 대체하기 전의 증발산량과 이상치를 대체한 후의 증발산량 사이에 차이를 보였으며, 특히 강우 시에 보다 큰 차이를 보였다. 따라서 증발산량 측정과정에서 발생하는 이상치를 보완하기 위해 이상치를 삭제하거나 대체하여 증발산량을 측정하는 것이 필요하다.

• 응용통계연구
• /
• 제29권7호
• /
• pp.1271-1281
• /
• 2016

야구에서 타자의 능력을 측정하는 많은 세이버메트릭스 통계량들 중에서 대체선수대비승수(wins above replacement; WAR)은 가장 많이 쓰이는 통계량이다. WAR은 선수의 공격능력과 주루능력, 수비능력 등을 하나의 수치로 표현하는 방법이란 점에서 큰 장점을 가지고 있다. 본 논문에서는 지난 3년간(2013-2015년) 한국프로야구 기록 자료를 바탕으로 세이버메트릭스 변수들의 값을 구한 뒤, 이를 이용하여 WAR을 대체할 수 있는 타자능력지수를 제안하였다. 타자능력지수는 산술평균방법, 가중평균방법, 주성분회귀분석 등을 통해 산출하고 WAR과 비교하여 가장 관계가 높은 방법을 선택하였다.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2007년도 추계학술대회 및 제23회 정기총회
• /
• pp.241-242
• /
• 2007

본 연구는 컨테이너 선박의 경제적 교체주기를 퍼지 연등가 비용법을 이용하여 결정하였다. 특히, 선박의 경제수명의 산출을 위한 비용에는 수많은 애매성이 존재하는데 이러한 애매성을 퍼지수로 표현하였다. 또한 퍼지수를 이용한 퍼지 비용모델을 개발하여 기존의 비용모델 보다 현실적으로 분석하는 방법을 제안하였다. 그리고 제안된 퍼지모델을 이용하여 다양한 크기의 컨테이너선을 대상으로 경제적 수명을 결정하였다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
• /
• pp.269-272
• /
• 2003

This study is intended to investigate the properties of concrete using AE Water Reducing Agent of Early-Strength Type. According to the results, as for the replacing method of mineral admixture, setting time is shortened faster in order of replacement for fine aggregate, combination and replacement for cement, and when AE Water Reducing Agent of Early-Strength Type is used, it is shortened by about 4 hours, compared with normal AE Water Reducing Agent Compressive strength is lower in the case of replacement for fine aggregate, but higher in the other case than that of plain concrete. And When AE Water Reducing Agent of Early-Strength Type is used, early compressive strength is very high in comparison to normal AE Water Reducing Agent. Early strength development is very favorable by the use of AE Water Reducing Agent of Early-Strength Type regardless of the replacing method of mineral admixture at $20^{\circ}C$, but at $l0^{\circ}C$, it is effective for Early strength development that W/B is lowered to below 45%, BS of 20% is replaced for fine aggregate, and AE Water Reducing Agent of Early-Strength Type is used.

• 한국국방경영분석학회지
• /
• 제3권1호
• /
• pp.109-114
• /
• 1977

There are some factors which cause the profits from the production to be decreased or increased. They are, for example, the rise in efficiency of production facilities resulting from the development of the scientific technique, the changes of purchase price of those, and the drop in efficiency of those owing to there long-term operation. In this connection, an manager can get the highest profit by deciding the proper time of new facilities replacement for those in operation or in being planned, which leads to good management planning of his manufactaring business for a given period or a long time. Main purpose of this is the study of how we decide the optimal time or facilities replacement in order to maximize the total profits for a given period by considering them as continous function as to the time in the case where a machineng is set. The results are following: 1. The definition of profit function is in duced in consideration of the breakdowns caused from continous operation of the machinery. 2. The necessary conditions are obtained for the optimal time of replacement and find out the methods of its solution. 3. Comparing between the 'Short cut' method and method in this paper, we obtained that our method is more realistic.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.691-699
• /
• 2008

In the design of a foundation, settlement of the foundation may exceed allowable design criteria even with a competent bearing stratum. In such a case, a piled-raft foundation system may be adopted using piles as settlement reducing component. In this paper, Disconnected Piled Raft Foundation (DPRF) system, which installs disconnected piles underneath the raft and uses the piles as ground reinforcements, is studied as a cost effective design method against the classical piled-raft foundation system. To this end, large size loading tests were carried out on weathered ground changing area replacement ratio and length of piles. The results indicated that the settlement of the reinforced ground was reduced by 34~87% and the allowable bearing pressure increased by 70% on average from those of the unreinforced original ground, respectively. The correlating formula between the area replacement ratio and the load bearing ratio of piles were derived from the test results and numerical analysis. From the correlation, a design method determining the size and the quantity of the disconnected piles to enhance the bearing capacity of original ground to the desired value was proposed based on one inch settlement criteria.

• Steel and Composite Structures
• /
• 제9권2호
• /
• pp.103-118
• /
• 2009

It has been reported that more than thirty five percent of steel bridges in the USA are structurally deficient because of structural degradations. The degraded structures need either full replacement or rehabilitation such that they are able to provide the required services for a longer period of time. The cost for repair in most cases is far less than the cost of replacement. Moreover, repair method generally takes less time than replacement and also reduces service interruption time. Modern advanced composites have been used in aerospace and automotive fields since World War II. In the recent past, because of the high strength-to-weight ratio and high stiffness-to-weight ratio, these composite materials have been introduced to civil engineering infrastructures primarily for repair and rehabilitation of concrete structures. However, only a few preliminary studies on repair of corroded steel structures using theses composite materials are reported in the literature available in the public domain. Thus, in this study, a series of laboratory tests was undertaken to evaluate the effectiveness of this repair method using carbon fiber reinforced polymer composite. The paper discusses the test method and test results obtained from these tests.

• Journal of Microbiology and Biotechnology
• /
• 제15권6호
• /
• pp.1346-1352
• /
• 2005

We have developed a modified gene replacement method using PCR products containing short homologous sequences of 40- to 50-nt. The method required $\lambda$-Red recombination functions provided under the control of a temperature-sensitive CI857 repressor expressed from the $P_{lac}$ promoter in the presence of IPTG on an easily curable helper plasmid. The method promoted the targeted gene replacements in the Escherichia coli chromosome after shifting cultures of the recombinogenic host, which carries the helper plasmid, to $42^{\circ}C$ for 15 min. Since this method employs $\lambda$-Red recombination functions expressed from the easily curable helper plasmid, multiple rounds of gene replacements in the E. coli chromosome would be possible. The procedures described herein are expected to be widely used for metabolic engineering of E. coli and other bacteria.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
• /
• pp.112-119
• /
• 2000

the shaking table tests for 5 different model sections are performed to investigate the behaviors of quay walls during earthquakes and to evaluate the seismic performance of quay walls with countermeasures. 5 different model sections describe the cases of dense soil and loose soil in the foundation repectively the case to which gravel backfill was applied and the cases to which light material replacement method and sand compction pile method was applied repectively for sesmic countermeasure methods. Pore water pressures accelerations and deformations in quay walls and grounds are analyzed. As a result the softening of foundation and backfill soils have much influence on the behaviors of quay walls. Also light material replacement method and sand compaction pile method are effective in improving the seismic performance of quay walls.