• Korean Journal of Remote Sensing
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• v.32 no.3
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• pp.275-285
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• 2016

This study analyzes the accuracy of ortho imagery based on whether camera calibration performed or not, using an unmanned aerial vehicle which equipped smart camera. Photgrammetric UAV system application was developed and smart camera performed image triangulation, and then created image as ortho imagery. Image triangulation was performed depending on whether interior orientation (IO) parameters were considered or not, which determined at the camera calibration phase. As a result of the camera calibration, RMS error appeared 0.57 pixel, which is more accurate compared to the result of the previous study using non-metric camera. When IO parameters were considered in static experiment, the triangulation resulted in 2 pixel or less (RMSE), which is at least 200 % higher than when IO parameters were not considered. After generate ortho imagery, the accuracy is 89% higher when camera calibration are considered than when they are not considered. Therefore, smart camera has high potential to use as a payload for UAV system and is expected to be equipped on the current UAV system to function directly or indirectly.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1109-1116
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• 2013

This study aims to investigate the spatial randomness of fatigue crack growth rate for the friction stir welded (FSWed) 7075-T651 aluminum alloy joints. Our previous fatigue crack growth test data are adopted in this investigation. To clearly understand the spatial randomness of fatigue crack growth rate, fatigue crack growth tests were conducted under constant stress intensity factor range (SIFR) control testing. The experimental data were analyzed for two different materials-base metal (BM) and weld metal (WM)-to investigate the effects of spatial randomness of fatigue crack growth rate and material properties, the friction stir welded (FSWed) 7075-T651 aluminum alloy joints, namely weld metal (WM) and base metal (BM). The results showed that the variability, as evaluated by Weibull statistical analysis, of the WM is higher than that of the BM.

• Journal of the Korean School Mathematics Society
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• v.12 no.1
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• pp.71-97
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• 2009

The study was to develop the instruments including instructional materials and test items for enhancing spatial ability. A mixed methodology was chosen to achieve the purpose of the study. To find students' achievement, 5 units of instructional materials were developed through the qualitative method and test items were tested through the quantitative method with 152 of the 8th-graders. The strategies to develop the instructional materials were: firstly to focus on mathematics properties for developing spacial ability; secondly, to allow students to follow hierarchical procedure o[ mathematical properties from 2-d to 3-d; thirdly, to recognize what the manipulative can do and can not; and fourthly, to guide students tn develop the process oriented thought, not the result oriented thought. For the test, 25 items were analyzed to assess students' achievement using validity, difficulty, and discriminator.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.9
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• pp.65-75
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• 2019

This study aims at analyzing the therapeutic design characteristics implemented in the indoor atriums of the outpatient areas in four children's hospitals in London and San Francisco. A mixed-method approach was used to examine the spatial configurations and design elements in the atriums, while a literature review was conducted to understand the therapeutic design characteristics relevant to atrium spaces and children's healthcare facilities. The spatial design and the pattern of use of the atrium in each hospital were studied during field visits and interviews with the hospital management staff. Based on the literature review and the observations from the field study, a Visibility Graphic Analysis was chosen to examine the visibility, accessibility, and intelligibility of the spatial configurations in the atriums of each hospital. In addition, the openness, restfulness, and vibrant ambience of the design elements in the atriums of each hospital were investigated by surveying fifty-two design professionals on the quality of the design elements in the atriums. A spatial configuration analysis, confirmed that all the atrium spaces had high visibility, accessibility, and intelligibility due to their high connectivity, integration, intelligibility, and because the atriums were laid out in the open lobby space, along the major circulation axis, or in the circulation intersection. In the survey of the design element evaluation, all atriums proved to be appropriate in terms of openness, while the adequacy of restfulness and vibrant ambience differed depending on the hospitals. Notably, location and orientation, access, natural light, outdoor view, and play facilities were found significant environmental design elements determining the successful implementation of the therapeutic design in the atriums. The observations from the aforementioned are further discussed to enhance the therapeutic design quality of atrium spaces in children's hospitals.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.3
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• pp.189-198
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• 2019

In photogrammetry, single photo resection is a method of determining exterior orientation parameters corresponding to a position and an attitude of a camera at the time of taking a photograph using known interior orientation parameters, ground coordinates, and image coordinates. In this study, we proposed a single photo resection algorithm that determines the exterior orientation parameters of the camera using cosine law and linear equation-based three-dimensional coordinate transformation. The proposed algorithm first calculated the scale between the ground coordinates and the corresponding normalized coordinates using the cosine law. Then, the exterior orientation parameters were determined by applying linear equation-based three-dimensional coordinate transformation using normalized coordinates and ground coordinates considering the calculated scale. The proposed algorithm was not sensitive to the initial values by using the method of dividing the longest distance among the combinations of the ground coordinates and dividing each ground coordinates, although the partial derivative was required for the nonlinear equation. In addition, since the exterior orientation parameters can be determined by using three points, there was a stable advantage in the geometrical arrangement of the control points.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.291-298
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• 2022

Recently developed drones are inexpensive and very convenient to operate. As a result, the production and utilization of spatial information using drones are increasing. However, most drones acquire images with a low-cost global navigation satellite system (GNSS) and an inertial measurement unit (IMU). Accordingly, the accuracy of the initial location and rotation angle elements of the image is low. In addition, because these drones are small and light, they can be greatly affected by wind, making it difficult to maintain a certain overlap, which degrades the positioning accuracy. Therefore, in this study, images are taken at different times in order to analyze the positioning accuracy according to changes in certain exterior orientation parameters. To do this, image processing was performed with Pix4D Mapper and the accuracy of the results was analyzed. In order to analyze the variation of the accuracy according to the exterior orientation parameters in detail, the exterior orientation parameters of the first processing result were used as meta-data for the second processing. Subsequently, the amount of change in the exterior orientation parameters was analyzed by in a strip-by-strip manner. As a result, it was proved that the changes of the Omega and Phi values among the rotation elements were related to a decrease in the height accuracy, while changes in Kappa were linked to the horizontal accuracy.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.143-149
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• 1998

When anesthetics were added to a bacteriorhodopsin (bR) in the purple membranes, the 570 nm absorption band shifts to 480 nm. This anesthetic-induced spectroscopic change is reversible. The apparent pKa (6.3) of this equilibrium depends on the nature of the anesthetics in which bR is dispersed. The electric orientation measurements showed that the native bR is easily achieved by relatively small electric field which is oriented at $60^\circ$, while anesthetic-treated bR is not the case. These results demonstrate that the subtle changes in the chromophore and the protein structure surrounding the chromophore by anesthetics influence the spatial orientation of the charged residues in the protein matrix surrounding chromophore.

• Economic and Environmental Geology
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• v.33 no.1
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• pp.77-88
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• 2000

The goal of this study is to assess the spatial distribution of natural slopes and cutting slopes under would-be development. For this goal, a quantitative slope stability analysis method using GIS integrated with a computer program was developed. Through field investigations, the discontinuity parameters were collected such as orientation of discontinuity, persistence, spacing, JRC, JCS, and water depth. The distributions were interpolated from the ordinary kriging method in ARC/INFO GIS after variogram analysis. The layers showing all parameters needed for limit equilibrium analysis were constructed. The final layer using GIS works composed of 162,352 polygons, that is, unit slopes. The rock slope stability analysis program was coded by C++ language. This program can calculate geometrical vectors related to rock block failures using input orientation data and direction and dimension of strength to occur failure. Also, this can calculate shear strength of joints through empirical equations and quantitative factors of safety. This methodology was applied to the study area which is located in Jaecheon city and Danyang-gun of the northeastern Keumsu is about 135$km^2$. As a result, the study area was entirely stable but unstable, that is, factor of safety less than 1.0dominantly at the slopes near Keumsil, Daejangri, Keumsungmyun and Sojugol, Mt. Dongsan, Juksongmyun by the natural slope stability analysis. Assuming the cutting slope showing the same direction immediate, and quantitative analysis of factors of safety for a regional area could be conducted through GIS integrated with a computer program of limit equilibrium.

• Proceedings of the KSRS Conference
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• v.2
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• pp.684-687
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• 2006

Airborne imagery must be precisely orthorectified to be used as geographical information data. GPS/INS (Global Positioning System/Inertial Navigation System) and LIDAR (LIght Detection And Ranging) data were employed to automatically orthorectify airborne images. In this study, 154 frame airborne images and LIDAR vector data were acquired. LIDAR vector data were converted to raster image for employing as reference data. To derive images with constant brightness, flat field correction was applied to the whole images. The airborne images were geometrically corrected by calculating internal orientation and external orientation using GPS/INS data and then orthorectified using LIDAR digital elevation model image. The precision of orthorectified images was validated using 50 ground control points collected in arbitrary selected five images and LIDAR intensity image. In validation results, RMSE (Root Mean Square Error) was 0.365 smaller then two times of pixel spatial resolution at the surface. It is possible that the derived mosaicked airborne image by this automatic orthorectification method is employed as geographical information data.

• Journal of the Korean housing association
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• v.17 no.5
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• pp.107-116
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• 2006

This study was to figure out the design characteristics of court housing type for the purpose of searching for the possibility of applying it to the housing design in Korea. In spite of changes of housing design condition in Korea, especially steep increase in density, there have been changes only in the height of housing block, not in the housing types, layout, spatial organization and other design properties. Due to such a situation, housing in Korea has been criticised as too high, monotonous one - especially types of housing block tend to be fixed into a slab block and a point block. As one of the alternatives to respond to the criticism, this study focused on the positive aspects of the court housing type, and suggested the design direction throughout the analysis of 8 entries in the design competition of EunPyeong New Town, which attempted to overcome the negative problems - mainly the daylighting, orientation, and privacy - and tried to maximize the positive properties of this type of housing.