• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.413-420
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• 2006

There are many Korean traditional wooden structures that have resisted successfully over more than several hundred years. However, their structural behavior is not known in engineering context yet. It is then difficult to predict how they behave against various loadings if they face. This paper is to attempt to investigate structural performance of the wooden structures using fuzzy concepts rather than definitely defined engineering formula. The fuzzy synthetic theory to a scoring method enables us to draw a representative and comprehensive value from individual quantity.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1317-1322
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• 2001

What changes in the eigen values and eigen functions are produced if the boundary surface S is no longer rigid but has a specific acoustic admittance which may vary from point to point on S. In this paper, changes in eigen values and eigen functions are derived by using Kirchhoff-Helmholtz integral equation. And acoustic potential energy, which is representative measure describing the physical quantity in cavity, is defined. Acoustic potential energy can be divided into primary one and secondary one. Primary one is the acoustic potential energy through unchanged eigen functions, and secondary one is through changed eigen functions. Using these two term, we can find the eigenvalue problem, which gives the control performance when the boundary condition is changed.

• 한국수소및신에너지학회논문집
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• 제31권6호
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• pp.630-636
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• 2020

This paper presents a experimental study on the performance of the heat pump. Uncertainty of measurement means the degree of uncertainty in the measurement. Therefore, it estimates a section where expected value of the measurement might be within a certain confidence level and suggests a range where measured representative value might be incorrect. Uncertainty of measurement is a parameter that shows characteristics of dispersion of measured value that was reasonably estimated from measured quantity. Measurement result of performance experiment is not a true value but estimated value that was estimated reasonably. Therefore, uncertainty of measurement needs to be calculated and presented with the result of measurement.

• International Journal of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.150-156
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• 2023

In a recent study, the phenomena of attention being drawn to the media business, particularly over-the-top (OTT) services, was the focus. Particularly, after the Squid Game was broadcast in September 2021, the total number of Netflix users had topped 213.6 million since the company first entered the domestic market. Domestic companies have also introduced OTT services like 'Wave', 'Tving', and 'Watcha Play' to capitalize on this market trend. However, questions persist about how Korea's native OTT providers, both large and small, are being harmed by Netflix's strong financial position and massive content quantity. In order to offer realistic performance metrics, we analyze Coupang Play among domestic OTT service providers after reviewing the business model and management strategy of representative OTT service firms.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.1112-1117
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• 2005

Construction cost index is generally used to estimate the new project cost based on past construction data and to adjust contract cost when the price change of various articles and items of expenditure composing the contract occurs. In Korea, it is mostly used for adjustment of construction contract cost due to fluctuation of prices. However index adjustment rate which is used for adjustment of construction contract cost had some problems in calculating cost index of each expenditure item that could not reflect properly the change of construction cost. For supplementing these problems, the research of developing construction cost index has been executed. Through the precedent research, these problems were partially resolved but still remain. Therefore this research proposes method of making cost index that utilizes representative items of labor, material, and equipment by analyzing bill of quantity of road construction, through analysis and comparison of precedent study. By using this method, it is expected to solve problems which were not reflected in precedent studies.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.114-115
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• 2021

본 논문에서는 지금까지의 양자 키 분배 기술에 대한 기본적인 개념과 기술적으로 발전해야 할 문제들을 소개하려 한다. 양자 키 분배 기술은 더이상 쪼갤 수 없는 물리량의 최소 단위인 양자(Quantum)의 특성을 이용해 도청 불가능한 암호키를 생성, 송신자와 수신자 양쪽에 나눠주는 기술이다. 이 기술의 대표적인 프로토콜인 BB84 프로토콜을 소개하고 현실적인 어려움과 앞으로의 과제를 살펴보고자 한다.

• 대한지역사회영양학회지
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• 제28권3호
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• pp.235-244
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• 2023

Objectives: Based on the results from the Korean Total Diet Study (KTDS), the sodium (Na) and potassium (K) intake of Koreans were estimated and compared with intake estimates from the Food & Nutrient Database (FNDB), as in the Korea National Health and Nutrition Examination Survey (KNHANES) to verify the validity of these estimates. Methods: One hundred and thirty-four representative foods (RFs) covering 92.5% of the total food intake of Koreans were selected, and 228 pairs of corresponding 'RF x representative cooking method' were derived by reflecting the methods used mainly in terms of frequency and quantity in their cooking. RF samples were collected from three cities with a larger population size in three regions (nine cities) nationwide, and six composite samples were made for each RF, considering its regional and/or seasonal characteristics. One thousand three hundred and sixty-eight 'RF x representative cooking method' pair samples were prepared, and the Na and K contents were assessed using inductively coupled plasma atomic emission spectrometry (ICP-MS). The Na and K intake of the Korean population was estimated by linking the content with the food intake data from the 7th KNHANES. Results: The mean Na and K intake of Koreans were 2,807.4 mg and 2,335.0 mg per person per day, respectively. A comparison with the Na and K intake from KNHANES, including only RFs of KTDS, showed comparable results with less than 5% variation. While the contribution and ranking of food items to Na intake were similar between KNHANES and KTDS, there were differences in K intake. This was attributed to the large discrepancies in the K content of rice and coffee between KTDS results and the values in the 9th Revision of the National Food Composition Table used in KNHANES. Conclusions: The Na and K intake of Koreans estimated based on the KTDS, which performed nutrient analysis on samples prepared to a 'table-ready' state using foods of the representative collection, was similar and comparable with that of KNHANES. This supports the validity and usefulness of FNDB-based nutrient intake estimation at the population level. The list of nutrients studied in KTDS is expected to be expanded, allowing for intake estimation of nutrients with currently insufficient or absent information in the FNDBs in use.

• 생약학회지
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• 제41권2호
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• pp.147-152
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• 2010

The capability of the solvents for extracting the bioactive saponins from the roots of Platycodon grandiflorum (Campanulaceae) was investigated to obtain an ideal extract which contained bioactive saponins with high quality and high quantity. The content of eight representative saponins in extracts, such as deapioplatycoside E, platycoside E, platyconic acid A and platycodin D, platycodin $D_3$, platycodin $D_2$, polygalacin $D_2$, polygalacin D were analyzed simultaneousely by the modified HPLC analytical method. The validation test of the modified qualitative and quantitative analytical method employing the ELSD equipped HPLC for eight representative saponins in the roots extract of P. grandiflorum showed a good linearity, precision and accuracy. the correlation coefficient ($r^2$) values of the calbration curves for each saponins were observed to be over 0.9990. LOD and LOQ of each saponin was calculated as $0.10{\mu}g{\sim}0.40{\mu}g$ (LOD) and $0.40{\mu}g{\sim}0.80{\mu}g$ (LOQ), respectively. Recovery rates of each saponin were also calculated as over 98%, respectively. With exception of two saponins, platyconic acid A and platycodin D, The content of eight saponins in extracts was decreased proportionally to the increment of the water ratio of solvent for extraction. Consequently, as aquous alcohol was used as a solvent for extracting the saponin components from powdered roots of P. grandiflorum, the water content in the aquous alcohol was seemed to be a critical factor for extracting efficacy. The 60-80% ratio of alcohol in the aquous alcohol were deduced to be suitable and recommendable for the preparation of roots extract of P. grandiflorum which contained saponins with high quality and high quantity.

• 산업경영시스템학회지
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• 제43권3호
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• pp.95-100
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• 2020

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. The representative type of the degeneration is wear of tool or machine. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore a periodic preventive resetting the process is necessary. The total cost consists of three items: adjustment cost (or replacement cost), non-conforming cost due to product out of upper or lower limit specification, and quality loss cost due to difference from the process target value and the product characteristic value among the conforming products. In this case, the problem of determining the adjustment period or wear limit that minimizes the total cost is called the 'process mean shift' problem. It is assumed that both specifications are set and the wear level can be observed directly. In this study, we propose a new model integrating the quality loss cost, process variance, and production volume, which has been conducted in different fields in previous studies. In particular, for the change in production volume according to the increasing in wear level, we propose a generalized production quantity function g(w). This function can be applied to most processes and we fitted the g(w) to the model. The objective equation of this model is the total cost per unit wear, and the determining variables are the wear limit and initial process setting position that minimize the objective equation.

• 대한토목학회논문집
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• 제43권2호
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• pp.267-275
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• 2023

최근 30년 이상 노후화된 국내 인프라의 증가로 한정된 예산 내에서 인프라 유지관리를 위한 정확한 유지관리 비용산출과 그에 따른 적절한 예산분배의 중요성이 증대되고 있다. 이에 본 연구에서는 콘크리트 교량의 대표적인 결함과 이에 대한 보수보강 공법들을 매칭하고 유지보수에 필요한 비용을 산정하였다. 표준품셈과 BMS (Bridge Management System) 데이터 분석을 통해 교량의 보수보강 공법을 분류하였으며, 결함의 위치와 종류, 크기에 따라 결함-공법을 매칭하였다. 그리고 표준품셈을 기준으로 단위당 작업량과 물량을 계산하여 노무비, 경비, 재료비를 구분하여 산출하였다. 서울시 교량 유지보수 내역서와 비교를 통해 평균 예측 정확도가 85.1 %가 나왔으며, 결함의 간단한 조건을 통해 유지보수 비용을 파악할 수 있다. 향후 현장 조건을 고려한 장비 및 야간작업 여부를 추가하여 더 높은 유지보수 비용을 파악할 수 있을 것으로 기대된다.