• International Journal of Highway Engineering
• /
• v.8 no.4 s.30
• /
• pp.87-99
• /
• 2006

This study was conducted to investigate whether the moisture variation aspects in pavement materials can be analyzed based on the convenient and reliable relative humidity(RH) measurement techniques. First, the ambient RH was measured using various sensors and the accuracies and calibration methods of the sensors were examined. Then, the RH of a cement mortar specimen was measured using the reliable sensors and the data was analyzed. In addition, the feasibility of using the RH measurement sensors to analyze the permeability of pavement materials was investigated. From this study, it was found that the Hygrochron was the most appropriate sensor to measure the RH of pavement materials, and the proper installation and calibration methods were developed. The RH of the cement mortar specimen tended to approach the ambient RH and was not much affected by the variation of the ambient RH. The specimen's RH variations at the surface and at the center showed a clear time lag. The RH measurement sensor was also found to be an appropriate tool for water permeability tests, and the methodologies to evaluate the permeability of pavement materials were proposed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.6
• /
• pp.598-603
• /
• 2019

Three-dimensional shape measurement technology is used in various industries. Among them, optical three-dimensional shape measurement techniques based on the optical trigonometry are mainly used in the field of semiconductor product inspection, where large quantities of three-dimensional shape measurements are made daily in factories and fine measurements are also required. The light source and the drive circuit, which are components of three-dimensional measurement equipment based on this optical trigonometry, produce heat generated by prolonged operation, and may be exposed to conditions where the ambient temperature is not constant, resulting in temperature-induced measurement errors. In this study, the compensation method of the Thermal Errors for Phase Measuring Profilometry is proposed. Three-Dimensional Shape Measurement Equipment based on Phase Measuring Profilometry is implemented to measure the height of an object and ambient temperature for 10 Hours, and a regression line was obtained line by making simple linear regression using measured temperature and height values. This regression line was used to correct the error of the height measurement according to the temperature, and thermal error was from 139.88 um(Micrometer) to 13.12 um.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2008.04a
• /
• pp.352-353
• /
• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2008.04a
• /
• pp.396-397
• /
• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2007.10a
• /
• pp.374-375
• /
• 2007

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.1355-1357
• /
• 2008

Reflection measurements are critical to the evaluation of display performance under ambient illumination conditions. Various hemispherical reflection methods are evaluated for their suitability and robustness across display technologies. The standard integrating sphere method is compared to a sampling sphere apparatus.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2001.11a
• /
• pp.333-334
• /
• 2001

대기 중 포름 알데하이드 연구의 중요한 이유는 인체에 대한 악영향을 끼치는 화합물이라는 점과 대기 중 거의 모든 유기화합물들의 광산화 반응 1차 생성물인 카르보닐 화합물 가운데 가장 풍부하게 존재하고 라디칼의 중요한 기원자로 작용하기 때문이다. 인체에 대한 악영향의 현상으로는 눈, 코, 목을 자극하고 기관지 천식, 피부 알레르기를 유발시키는 것으로 나타나고 최근에는 동물과 인간의 발암물질로도 확인되어지고 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2002.04a
• /
• pp.141-142
• /
• 2002

대기환경 기준물질(criteria pollutants)은 NOx를 비롯하여 $O_3$, CO, SOx, PM 10, Pb 인데, 이러한 물질은 환경부에서 법적으로 규정한 대기오염공정 시험법에 따라서 분석된다. 대기오염공정 시험법이 충분한 과학적 근거를 갖는 분석법이 되기 위해서는 분석방법, 분석기기, 분석자 등에 의해 발생되는 불확실성을 최소화시키는 체계적인 관리가 필요하고, 분석기술의 발달수준, 측정분석의 요구수준, 새로운 국제 규격 통에 맞게 지속적으로 보완되어야 한다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2001.11a
• /
• pp.367-368
• /
• 2001

휘발성 유기화합물질들(VOCs)은 그 자체가 인체에 유해한 화합물로 작용할 뿐만 아니라 환경대기 중에서 질소화합물(NOx)과 광화학 반응을 통하여 오존 등 유해한 산화물을 형성하는 전구물질로 작용하여 이들의 거동을 이해하고 분석하는 것이 대기환경에 매우 중요한 것으로 인식되고 있다. 더욱이 오존 예보 및 경계 체제의 중요한 입력 요인으로 인식되어 신뢰성 있는 배출 정보의 산출을 위해 VOCs 농도를 현장 실측하여 분석하고 예보에 이용하려는 시도가 이루어지고 있다. (중략)

• Smart Structures and Systems
• /
• v.10 no.4_5
• /
• pp.485-499
• /
• 2012

Mode shape expansion is useful in structural dynamic studies such as vibration based structural health monitoring; however most existing expansion methods can not consider the modelling errors in the finite element model and the measurement uncertainty in the modal properties identified from vibration data. This paper presents a reliable approach for expanding mode shapes with consideration of both the errors in analytical model and noise in measured modal data. The proposed approach takes the perturbed force as an unknown vector that contains the discrepancies in structural parameters between the analytical model and tested structure. A regularisation algorithm based on the Tikhonov solution incorporating the L-curve criterion is adopted to reduce the influence of measurement uncertainties and to produce smooth and optimised expansion estimates in the least squares sense. The Canton Tower benchmark problem established by the Hong Kong Polytechnic University is then utilised to demonstrate the applicability of the proposed expansion approach to the actual structure. The results from the benchmark problem studies show that the proposed approach can provide reliable predictions of mode shape expansion using only limited information on the operational modal data identified from the recorded ambient vibration measurements.