• Journal of The Korea Institute of Healthcare Architecture
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• v.23 no.2
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• pp.19-26
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• 2017

Purpose: With the increasing of public-use facilities, there has been a growing concern over Indoor Air Quality(IAQ) of public-use facilities. Because the facilities are easy to be exposed to indoor air pollutants, they needs to be periodically managed the IAQ. Methods: In this study, indoor air pollutant concentrations of 24 vulnerable facilities were measured and compared. The measurements were conducted for pollutants which are defined in 'IAQ Control In Public-Use Facilities, etc. Act'. We took two measurements, the first was carried out in summer and the second was proceeded in winter. We analyzed the values according to the type of facilities and pollutants. Results: There was a difference in pollutant concentrations by the season and in occurrence characteristics by the measurement spot. Therefore, we need to manage pollutant concentrations by characteristics of occurrence. Implications: Based on the comparative analysis of pollutant concentrations, we suggested cause and improvement strategies for IAQ management of Vulnerable facilities.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.4 no.2
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• pp.10-26
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• 1986

In a stereoscopic measurements on the aerial photogrammetric works, it is in general understood that the larger and the larger is a vertical scale exaggeration, the better and the better is height measuring precision. Despite the success with which a stereoscopic measurement has been applied to contour mapping as well as spot height measurement, no generally accepted theory for visual excess has yet been developed. This experiments aim at arrangement of a correlation between visual excess and height measuring precision. The stereoscopic measurements with parallax bar in the mirror stereoscope are carried out on the test model of which consists normal angle, wide angle and super wide angle respectively. With the result of this experiments, it is conclued that height measuring precision is proportional to the magnitude of visual excess.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.383-390
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• 2006

The SharkHartmann wavefront sensors are the most popular devices to measure wavefront in the field of adaptive optics. The Shack-Hartmann sensors measure the centroids of spot irradiance distribution formed by each corresponding micro-lens. The centroids are linearly proportional to the local mean slopes of the wavefront defined within the corresponding sub-aperture. The wavefront is then reconstructed from the evaluated local mean slopes. The uncertainty of the Shack-Hartmann sensor is caused by various factors including the detector noise, the limited size of the detector, the magnitude and profile of spot irradiance distribution, etc. This paper investigates the noise propagation in two major centroid evaluation algorithms through computer simulation; 1st order moments of the irradiance algorithms i.e. center of gravity algorithm, and correlation algorithm. First, the center of gravity algorithm is shown to have relatively large dependence on the magnitudes of noises and the shape & size of irradiance sidelobes, whose effects are also shown to be minimized by optimal thresholding. Second, the correlation algorithm is shown to be robust over those effects, while its measurement accuracy is vulnerable to the size variation of the reference spot. The investigation is finally confirmed by experimental measurements of defocus wavefront aberrations using a Shack-Hartmann sensor using those two algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.380-385
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• 2006

In this paper, a program that can be utilized to measure and analyze radio propagation characteristics is developed. This program is able to control the measurement instruments including spectrum analyzer through GPIB interface and analyze the measured data to yield mean excess delay and RMS delay spread. The measured path loss can be compared with theoretical value in free space or inside a tunnel. The measured and analyzed results can also be presented in the forms of graphs. As these tasks can be conducted on the spot of the measurements, this program is very helpful in performing and verifying the measurements immediately. In this thesis radio propagation characteristics with frequency bands of 2.45 and 5.8GHz in subway tunnels are measured by using the program. Path loss and delay spread in subway tunnel is measured and compared according to the form of antenna beam and LOS(Line of Sight) and N-LOS(Non-Line of Sight).

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.75-76
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• 2003

Current efforts to establish links between geometrical features and mechanical performance of nonwoven fabrics in general, and of point-bonded (spot-bonded) nonwovens in particular, would be served significantly by the measurements of Fiber Orientation Distribution Function (ODF) and tensile modulus which occurs during controlled-deformation experiments. Image analysis technique (using the Fast Furier Transform) is used to quantify the fiber orientation distribution. The results suggest that, within a typical window of processing conditions, ODF has a significant influence on the mechanical anisotropy. The data also suggest that mechanical anisotropy of thermally point-bonded nonwovens is likely to be governed by different stress mode according to the applied macroscopic tensile direction.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.217-220
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• 2005

Currently, a number of control points are required in order to achieve accurate geolocation of satellite images. Control points can be generated from existing maps or surveying, or, preferably, from GPS measurements. The requirement of control points increase the cost of satellite mapping, let alone it makes the mapping over inaccessible areas troublesome. This paper investigates the possibilities of modeling an entire imaging strip with control points obtained from a small portion of the strip. We tested physical sensor models that were based on satellite orbit and attitude angles. It was anticipated that orbit modeling needed a sensor model with good accuracy of exterior orientation estimation, rather then the accuracy of bundle adjustment. We implemented sensor models with various parameter sets and checked their accuracy when applied to the scenes on the same orbital strip together with the bundle adjustment accuracy and the accuracy of estimated exterior orientation parameters. Results showed that although the models with good bundle adjustments accuracy did not always good orbit modeling and that the models with simple unknowns could be used for orbit modeling.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.48-53
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• 1997

Electronic Speckle Pattern Interferometry(ESPI) using the Model 95 Ar laserm, a video system and an image processor was applied to the in-plane displacement measurements. Unlike traditional strain gauges or moire method, ESPI method requires no special surface preparation or attachments and can be measured in-plane displacement with no contact and real time. In this experiment wpecimen was loaded in parallel with a loadcell. The specimen was the cold rolled sdteel sheet of 2mm thickness, which was attached strain gauges. The study provides an example of how ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI compare with the data which was measured by strain gauge method in tensile testing.

• Journal of Information Display
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• v.5 no.3
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• pp.35-40
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• 2004

In this study, we collected data used to formulate the relationship between quantitative metrological parameters in CRT display and the perceived focus quality. Human perception of the focusing quality was evaluated in terms of user feedback scores regarding the character legibility from four highly trained inspectors. Thirteen CRT monitors from five different manufacturers were compared relatively with respect to the norm monitor. The profile of electron beam such as spot size and the shape of distribution made by electron beam, contrast, convergence of RGB beams, and luminance characteristics were measured using a precision measurement system. Linear regression analysis and artificial neural network models were used to formulate the relationship between human perception and the quantitative measurements. The accuracy of the formulated linear regression model ($R^2$=0.515) was not satisfactory but the nonlinear neural network model ($R^2$=0.716) was fairly convincing and robust even the utilized data included subjective differences.

• Fibers and Polymers
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• v.5 no.3
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• pp.177-181
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• 2004

Current efforts to establish links between geometrical features and mechanical performance of nonwoven fabrics in general, and of point-bonded (spot-bonded) nonwovens in particular has been made using the measurements of Fiber Orientation Distribution Function (ODF) and tensile modulus which occurs during controlled-deformation experiments. Image analysis technique (using the Fast Fourier Transform) was used to quantify the fiber orientation distribution. The results suggest that, within a typical window of processing conditions, the fiber orientation has a significant influence on the anisotropical behavior of nonwoven. The data also suggest that mechanical anisotropy of thermally point-bonded nonwovens is likely to be governed by different load transfer mechanism according to the applied macroscopic tensile direction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.951-954
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• 2003

Generally, for the burrs formed in machining are irregular and very sharp in shape, it is usually very difficult to measure burr accurately. But, it is proved that precision measurement for micro burr using the conoprobe sensor by conoscopic holography method is possible. We developed 3D burr measurement system using this sensor. The system is composed of Conoscopic laser Sensor, X-Y table, controller and 3D measurement program. Some measurements using the developed system are applied to burrs formed in micro drilling and piercing.