• 한국진공학회지
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• 제14권2호
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• pp.59-68
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• 2005

부피가 다른 세 개의 진공용기를 조합하여 정적법 (static expansion method)을 이용한 중진공영역의 국가표준기를 개발하였다. 이 장치를 이용하여 133pa 범위의 용량형 진공게이지 (capacitance diaphragm gauge)를 교정하여 국제표준화기구의 측정불확도 표현지침에 따라 분석하였다. 그 결과 표준압력 0.553Pa에서의 확장불확도 (expanded uncertainty)가 95% 신뢰수준 (confidence level), 포함인자 (coverage factor) k=2에서 $2.628\times10^{-3}Pa$로 우수한 성능을 보였다.

• 한국문헌정보학회지
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• 제38권3호
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• pp.103-118
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• 2004

인터넷 서비스가 안정화 위주로 옮겨가면서 웹서비스의 품질 향상을 위해 보다 많은 투자가 이루어지고 있다. 대규모의 다양한 정보를 제공하고있는 전자도서관 웹 사이트가 객관적인 평가 시스템을 개발하여 적용하므로써 이용자들에게 서비스의 만족도를 높일 수 있는 기준을 마련할 필요가 있다. 본 연구에서는 검색성, 개인화로 기준을 도출하였다. 구축된 사용성 평가 모델을 계층적 분석방법(Analytic Hierarchy Process AHP)을 이용하여 평가하고 검증하였다. 평가지침으로 설정된 항목을 설문조사를 하여 계층적 분석방법에 기초한 디지털 도서관 웹 사이트 평가 모델을 개발하였다.

• 한국대기환경학회지
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• 제17권4호
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• pp.313-319
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• 2001

The development of ozone SRP (Standard Reference Photometer) designated as a G-7 project by the Korean Ministry of Environment began 1997 and is now nearly completed. With the completion of the ozone SRP we will not only acquire a qualification to participate in the international ozone calibration system but also enhance calibration credibility of ozone similarly to that of other ambient air pollution monitors. As the ozone SRP uses highly cleaned blank air that can be distinguished from general ozone analyzer, it is possible to reduce errors associated with the determination of ozone via elongation of the absorption length as long as 1 meter In addition, gas chopping method hat been adopted to cut down interference of other substances and time drift. Furthermore, the system has also been modified to minimize the strayed ultra-violet noise along the light path. In this paper, a new method for uncertainty evaluation has been introduced, which is guided by the ISO (International Standard Organization) GUM (Guide to the Expression of Uncertainty in Measurement) through assessments of the uncertainty type B (that was impossible to estimate before) as well as the uncertainty type A (based on statistics).

• 한국대기환경학회지
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• 제18권5호
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• pp.355-362
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• 2002

There has been relatively a few studies that focused on evaluation of uncertainty for standard methods by which criteria pollutants are analyzed in ambient air. Especially, uncertainty evaluation has not been made yet for sampling and analysis of airborne NO$_2$. Ambient NO$_2$ has been thought to be a major criteria pollutant worldwide because of the potential of ozone formation as well as of its own toxicity. In this study, we tried to assess uncertainties associated with the every step of sampling and of analytical procedure of Griess-Saltzman method. Quality assurance (QA) and quality control (QC) were also emphasized with the uncertainty characterization. The use of Griess-Saltzman method for ambient NO$_2$ analysis showed very uniform daily concentration distribution with the mean of 10.8 ppb and the standard deviation of 1.08ppb during the sampling period. However, seven daily samples collected at the same sampling time and place exhibited highly different concentration distribution. Therefore, we evaluated uncertainties associated with sampling and analysis through the precise application of ISO Guide. Estimates of expanded uncertainties for a total of 62 samples fell in a relatively broad range of 5.17% to 11.85%. On the other hand. the expanded uncertainties were smaller for the high concentration range of greater than 15ppb.

• 교육녹색환경연구
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• 제12권2호
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• pp.11-18
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• 2013

Since the Standard Design Guide in 1962 and "School Facility Facility Standard Regulation" established in 1969, the elementary school facility in Korea has been amended and complemented. The modern pilot school was started in 1991 and every elementary school facility has been designed based on the modern elementary school from 1994. At present, 8 out of 28 closed schools occurred in the downtown area in Daegu. One of them is located in rent and 7 are used by themselves. The rest 20 schools are located in Dalsung-gun and most of them have old buildings of straight plane shapes built in 1940s. The purpose of this basic study is to pursue the changing process of closed schools based on policy changes of curriculum and to seek the qualitative change when using closed schools. In addition, it is to prepare the using measures when the school close is occurred in the downtown area in the future by classifying and analyzing plane types according to their types.

• 한국유체기계학회 논문집
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• 제12권5호
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• pp.47-53
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• 2009

A rotordynamic and detailed stability analysis in accordance with API 617 standard were performed with a turbo-compressor, which is one of key rotating machinery in refinery, petroleum, and power plants. The system is composed of rotor shaft, impeller, sleeve hub, balance drum, and coupling hub. The rotor system is supported by tilting pad bearings, which has 5 pads and pad on loading condition. The rotordynamic analysis specified by API 617 includes the critical speed map, mode shape analysis, Campbell diagram, unbalance response analysis, and stability analysis. In particular, the specifications of stability analysis consist of a Level 1 analysis that approximates the destabilizing effects of the labyrinth seals and aerodynamic excitations, and Level 2 analysis that includes a detailed labyrinth seal aerodynamic analysis. The results of a rotordynamic analysis and stability analysis can evaluate the operating compressor health and can be utilized as a guide of its maintenance, repair and trouble solution.

• 한국정밀공학회지
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• 제14권11호
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• pp.42-49
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• 1997

The extent of absorption and transmitance of the light that passes through some material is changed as the wavelength of the light varies, and which makdes it possible to estimate characteristics of the material. Spectrometer is a measurement system that can analyze the characteristics of material by using this principle. Its application field is so wide that it can be applied to all the arease that are concerned with analyzing materials : biological, environmental, medical and chemical area etc. This study is focused on developing precision sine drive mechanism for grating monochromator which is the most important part of the spectrometers. It is designed to be simple in struicture. It is achieved to derive basic principles to manipu- late precision sine drive mechanism : it should be aligned with a condition that .beta. , the angle between grat- ing normal and grating rod should be the same as .gamma. , the one between moving nut's normal and sliding guide. And also, it's found that the mis-alignments of the grating and mirrors are not the main factor in guaranteeing the linearity of sine drive mechanism. Performance evaluation is achieved by a standard sample by comparing experimental results with standard values. It results in wavelength accuracy of .+-. 0.5nm and resolution of 1nm. Conclusively, it can be verified that the sine drive mechanism developed in this study is not only simple in structure, but also stable and excellent in performanes.

• KSBB Journal
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• 제32권1호
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• pp.54-62
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• 2017

This study aimed to estimate the measurement uncertainty related to determination of hyaluronic acid used as a dietary supplement by high-performance liquid chromatography. According to the guidelines of the Association of Official Analytical Chemists, the analytical processes for determination of hyaluronic acid were performed. And the measurement uncertainty obtained during the analytical processes were expressed in accordance with mathematical/ statistical guidances of GUM (Guide to the Expression of Uncertainty in Measurement) & EURACHEM (Focus for Analytical Chemistry in Europe) for the analytical operations. For the uncertainty in measurement produced based on this analytical method, the expanded uncertainty was calculated by using the relative standard uncertainty between analytical results and sources of uncertainty in measurement (sample weight, final volume, extraction volume, standard solution, matrix and instrument etc). In the results of 95% confidence interval, it was calculated that the uncertainty in measurement was $57.75{\pm}8.76{\mu}g/kg$ (k=2.0). Therefore, it showed that the measurement uncertainty obtained by this analytical method influences on 15.2% of the contents of hyaluronic acid as the analytical results.

• Safety and Health at Work
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• 제5권3호
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• pp.125-130
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• 2014

Background: Construction industry is among the most hazardous industries, and needs a comprehensive and simple-to-administer tool to continuously assess and promote its health and safety performance. Methods: Through the study of various standard systems (mainly Health, Safety, and Environment Management System; Occupational Health and Safety Assessment Series 180001; and British Standard, occupational health and safety management systems-Guide 8800), seven main elements were determined for the desired framework, and then, by reviewing literature, factors affecting these main elements were determined. The relative importance of each element and its related factors was calculated at organizational and project levels. The provided framework was then implemented in three construction companies, and results were compared together. Results: The results of the study show that the relative importance of the main elements and their related factors differ between organizational and project levels: leadership and commitment are the most important elements at the organization level, whereas risk assessment and management are most important at the project level. Conclusion: The present study demonstrated that the framework is easy to administer, and by interpreting the results, the main factors leading to the present condition of companies can be determined.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.331-340
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• 2009

This study is objected by suggesting rationalization method of management and maintenance cost for railway investment assessment. The estimate of rational benefit and cost are a work of vital importance to decide railway investment as preliminary feasibility investigation is institutionally reinforced since January 2007. In particular, railway management and maintenance cost have to be applied to realistic and detail cost as railway investment assessment guide. For example, types of railway, construction of new line, improvement of conventional line, double tracking, railway electrification. However, railway investment assessment is inconsistency because of estimating the railway management and maintenance cost using existing unrealistic management and maintenance cost. Therefore, this study is performed parametric analysis effecting on the railway management and maintenance cost considered new technique, enhanced facilities and improved standard. Also, it suggests the itemized standard management and maintenance cost. Finally, it will be helped to establish the base of railway investment through the rationalization method of management and maintenance cost.