• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1073-1078
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• 2000

This study is to investigate the effect of construction element such as the number of CFS ply, curing temperature, splice length and curing periods on the mechanical properties of Carbon Fiber Sheet (CFS). Through the tensile tests of CFS specimens, it can be said that the reduction factor stemmed from the number of CFS ply must be considered in the calculation of the design tensile strength of CFS. Also, the minimum splice length of CFS and curing period in $20^{\circ}C$ to satisfy the standard tension strength of CFS are over 5cm and after 3days, respectively. The measuring error of epoxy resin have no effect to tension strength of CFS until $\pm$20% error.

• 한국태양에너지학회 논문집
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• 제27권1호
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• pp.1-9
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• 2007

This paper reveals both the operational situation and the cause of the error occurred in wind turbine generator system of Hangwon wind farm in Jeju island. The four wind turbines were selected for this work, and the monitored period was for six months. Wind resource in the wind farm was analyzed, and the estimated energy production was compared with the actual energy production. As a result, with a decrease of system error, the estimated energy production was in good agreement with the actual energy production. The errors occurring in components such as gearbox and hydraulic motor affected the Availability of the wind turbine. Also, poor external conditions such as a strong wind, lightning and gust caused a standstill of wind turbines.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.108-109
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• 2019

Top-down construction is a useful method of utilizing the working space, economic benefits and shorten the construction period. Precision construction of the elevator core is very important for safety of the top-down structure. In this study, the layout system for the field-BIM(Building Information Modeling) was used to precisely construct the elevator core in the basement and the ground. Through the layout system, it was possible to process the construction status, review the design results and construction errors, and confirm whether there is or not within the construction error range for elevator installation.

• 한국항만경제학회지
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• 제32권4호
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• pp.165-182
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• 2016

본 논문은 동아시아의 주요 컨테이너항만 간의 경쟁 및 보완 관계를 분석하는 데 그 의의가 있다. 분석의 대상이 되는 항만들은 컨테이너 기종점 물동량 규모로 세계 최대인 중국의 6개 주요 항만과 환적 물동량 규모로 세계 최대인 싱가포르, 홍콩, 부산의 항만이며, 지리적으로는 동아시아에 밀집된 항만들이다. 본 연구에서는 2008년부터 2015년까지의 월간 컨테이너 물동량에 대한 시계열 자료를 이용하여 항만 간의 동태적 관계를 분석하였으며, 벡터오차수정모형(Vector Error Correction Model)에 기초하여 다음과 같이 분석하였다. 먼저 그랜저 인과관계 검정을 통해 항만 간의 상호관계를 규명하고자 하였다. 그리고 이어서 공적뿐 검정을 통해 관련 있는 두 항만 간의 장기적인 균형관계를 살펴보고자 했으며, 아울러 충격반응함수 및 표준변차의 분산분해 과정을 통해 단기적인 영향에 대해서 밝히고자 하였다. 결과를 살펴보면, 먼저 그랜저 인과관계 검정과 공적뿐 검정의 결과, 부산과 홍콩 및 싱가포르의 환적 물동량은 중국 내륙의 주요 기종점 물동량에 대해 상호적으로 또는 일방적으로 경쟁적인 관계가 있음을 보여주었다. 그러나 환적 물동량 간의 인과관계는 상호적으로는 유의미하게 나타나지 않았으며, 공적분도 존재하지 않았다. 다만 분산분해의 결과를 통해 단기적이고 부분적으로 충격에 차지하는 비중을 확인해 본 결과 홍콩항의 환적 물동량이 부산항과 싱가포르항의 환적 물동량에 차지하는 비중이 높아지고 있음을 알 수 있었다. 충격반응함수의 결과를 종합해 보면, 분석의 대부분에서 2기가 지나는 시점에 충격의 여파가 최대가 되며, 6기가 지나면서 그 충격은 소멸되었다. 본 연구에서 분석한 결과로 확인할 수 있는 것은 환적 항만 간의 관계가 경쟁적이라고 할 수 없다는 사실과 오히려 기종점 항만과 환적 항만의 경쟁 관계가 발생한다는 것이다. 이것은 기종점 물동량에 의해 파생된 환적 물동량이 기종점 물동량의 증가에 따라 항상 증가하지 않으며 오히려 감소될 수 있음을 설명하고 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3097-3100
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• 2015

Projections of cancer cases are particularly useful in developing countries to plan and prioritize both diagnostic and treatment facilities. In the prediction of cancer cases for the future period say after 5 years or after 10 years, it is imperative to use the knowledge of past time trends in incidence rates as well as in population at risk. In most of the recently published studies the duration for which the time trend was assessed was more than 10 years while in few studies the duration was between 5-7 years. This raises the question as to what is the optimum time period which should be used for assessment of time trends and projections. Thus, the present paper explores the suitability of different time periods to predict the future rates so that the valid projections of cancer burden can be done for India. The cancer incidence data of selected cancer sites of Bangalore, Bhopal, Chennai, Delhi and Mumbai PBCR for the period of 1991-2009 was utilized. The three time periods were selected namely 1991-2005; 1996-2005, 1999-2005 to assess the time trends and projections. For the five selected sites, each for males and females and for each registry, the time trend was assessed and the linear regression equation was obtained to give prediction for the years 2006, 2007, 2008 and 2009. These predictions were compared with actual incidence data. The time period giving the least error in prediction was adjudged as the best. The result of the current analysis suggested that for projections of cancer cases, the 10 years duration data are most appropriate as compared to 7 year or 15 year incidence data.

• 한국정밀공학회지
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• 제22권3호
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• pp.101-106
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• 2005

It needs to accumulate a store of know-how on the design, precision processing and appraisement for metering pump which is a kind of gear pump fer synthetic fibers. But the period and cost fur development is not effective, because designers experience many trial and error for the pump design and manufacturing process. Therefore, in order to curtail the period and cut down expenses, the analysis and simulation system is required for a designed metering pump. In this study, the pump simulation software was developed with the visual C++ language and the image processing algorithm, and was investigated through a discharge test for the planetary gear type metering pump.

• 한국경영과학회지
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• 제35권4호
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• pp.33-53
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• 2010

When purchase prices of a raw material fluctuate over time, the total purchasing cost is mainly affected by reordering time. Existing researches focus on deciding the right time when the demand for each period is replenished at the lowest cost. However, the decision is based on expected future prices which usually turn out to include some error. This discrepancy between expected prices and actual prices deteriorates the performance of inventory models dealing with fluctuating purchase prices. In this paper, we propose a new inventory model which incorporates not only cost but also risk into making up a replenishment schedule to meet each period's demand. For each replenishment schedule, the risk is defined to be the variance of its total cost. By introducing the risk into the objective function, the variability of the total cost can be mitigated, and eventually more stable replenishment schedule will be obtained. According to experimental results from crude oil inventory management, the proposed model showed better performance over other models in respect of variability and cost.

• 산업공학
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• 제4권1호
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• pp.63-69
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• 1991

In this paper, the Go-Back-N ARQ protocol with decoding in communication network is considered. The time delay and throughput are respectively analyzed as a function of window size and decoding time out. Packets arrive continuously at the decoder, and are stored in a buffer if the decoder is busy upon its arrival. The decoder devotes no more than a time-out period of predetermined length to the decoding of any single packet. If packet decoding is completed within that period, the packet leaves the system. Otherwise, it is retransimitted and its decoding starts anew. The time delay and throughput are obtained using recursive formula and difference equation. An appropriate time out and window size that satisfies the grade of service can be determined.

• 한국경영과학회지
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• 제28권1호
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• pp.11-23
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• 2003

This study Investigates the short and long-run dynamic relationships between the domestic and U.S. stock markets for the period of declining stock prices. It Is well known that the domestic stock market variations are largely caused by the U.S. stock market movements. Multivariate causal tty test Is utilized to examine the lead-lag relationships among four stock prices of KOSPI and KOSDAQ In the domestic part and DOWJONES and NASDAQ In the U.S. part. When the stock prices tend to decrease In the long run, It Is found that both KOSPI and KOSDAQ have closer relations with NASDAQ than DOWJONES. When both of domestic stock markets are severely fluctuate, bidirectional causal relationships appear to exist between NASDAQ and each of KOSPI and KOSDAQ. On the other hand. when the domestic stock markets are relatively stable, unidirectional causality Is found to exist between NASDAQ and each of KOSPI and KOSDAQ. which is explicitly validated by the analysis of variance decomposition.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.38.2-38.2
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• 2008

In Korean historical documents, there are a great number of the records for various astronomical events. In particular, historical documents of the Joseon dynasty also have the records containing observational data by an astronomical instrument. However, a quantitative analysis for the accuracy of observational values have never been studied, although there are some studies on the truth of the records themselves. Hence, we investigated observation errors during the period of the Joseon dynasty from the records of Joseon-Wang-Jo-Sil-Lok (the Annals of the Joseon Dynasty) and Seung-Jeong-Won-Il-Gi (Daily Records of the Royal Secretariat). We used the records of the Mars, supernova 1604, and Halley's Comet, and found that observational values before the Hideyoshi invasions in 1592 are relatively more accurate than those after then. However, because the number of cases used in this study is small, we think that more studies are needed to confirm our results. Nonetheless, we reckon our work will be of service to understand astronomical records of the Joseon dynasty.