• Korean Journal of Optics and Photonics
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• v.34 no.2
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• pp.61-65
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• 2023

This paper studies a method of applying pre-distortion to the image mask of the gobo illumination optical system to correct an irradiated image and irradiate a clear image. In the case of the gobo illumination optical system, since it is generally irradiated with a tilt, distortion in the upper and lower directions occurs severely in the image. To solve this problem, the correction coordinates of the image were derived using a proportional equation, and the distortion was corrected by applying them to the image mask. As a result, it was confirmed that the distortion was reduced by 64.5% compared to the case of using the existing image mask.

• Economic and Environmental Geology
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• v.29 no.3
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• pp.369-380
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• 1996

In order to determine the emplacement time and stratigraphic position of basaltic rocks in the central part of Pohang basin, palaeomagnetic investigations were conducted on 111 samples collected from 6 sites. Formation mean built from site-mean ChRM directions is $d=340.7^{\circ}$, $i=52.2^{\circ}$ (${\alpha}_{95}=6.0^{\circ}$, k=91) in the geographic coordinates. If "tilt" correction is applied regarding the plane perpendicular to the side walls of columnar joint as palaeohorizon, the formation mean becomes $d=328.7^{\circ}$, $i=43.8^{\circ}$ (${\alpha}_{95}=17.1^{\circ}$, k=13). It is to be noticed that the formation mean is deflected significantly (about $20{\sim}30^{\circ}$) counterclockwise from the Tertiary reference geomagnetic field of Eurasia, independent of "tilt" correction. This situation is very different from that of clockwise rotation of ChRM directions which has been ubiquitously observed in other Tertiary basins of south Korea, and indicates sinistral regional simple-shearing during the emplacement times of the basaltic rocks. Considering previous palaeomagnetic and AMS (anisotropy of magnetic susceptibility) data from other Tertiary regions of south Korea, the time of this sinistral shearing should be 15 Ma or directly thereafter, and this time point represents inversion from extensional to compressional tectonic regime. Magnetic foliation data obtained in this study indicate WNW-ESN compression during or directly after emplacement of the basaltic rocks, while it has known from regional tectonic study that the time of the WNW-ESN compression is about 15 Ma, when SW Honshu was rotated and the Korean strait was narrowed.

• Ecology and Resilient Infrastructure
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• v.8 no.2
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• pp.88-96
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• 2021

In surface image velocimetry, a wide area of a river is photographed at an angle to measure its velocity, inevitably causing image distortion. Although a distorted image can be corrected into an orthogonal image by using 2D projective coordinate transformation and considering reference points on the same plane as the water surface, this method is limited by the uncertainty of changes in the water level in the event of a flood. Therefore, in this study, we developed a tilt image correction technique that corrects distortions in oblique images without resetting the reference points while coping with changes in the water level using the geometric relationship between the coordinates of the reference points set at a high position the camera, and the vertical distance between the water surface and the camera. Furthermore, we developed a distortion correction method to verify the corrected image, wherein we conducted a full-scale river experiment to verify the reference point transformation equation and measure the surface velocity. Based on the verification results, the proposed tilt image correction method was found to be over 97% accurate, whereas the experiment result of the surface velocity differed by approximately 4% as compared to the results calculated using the proposed method, thereby indicating high accuracy. Application of the proposed method to an image-based fixed automatic discharge measurement system can improve the accuracy of discharge measurement in the event of a flood when the water level changes rapidly.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.2
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• pp.130-135
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• 2007

Wind tunnel test for Smart UAV power model has been conducted at KARI LSWT for about 3 months. The static model is used for the base plane and the power effect of tilt rotor is simulated by the tilt-rotor test rig installed in the test section. Although the genuine power effect is the difference between power-on and off tests. The existence of struts for power effect test produced unwanted form of interference and caused the change in flow angularity. To precisely evaluate power effect, a special approach is applied to Smart UAV test.

• Journal of Korean Medical Ki-Gong Academy
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• v.20 no.1
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• pp.118-147
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• 2020

Objective : The purpose of this study is to understand trends of pelvic correction therapy in Korea and to assist research activities on pelvic correction therapy. Also, this study selected and presented indicators for measuring pelvic slope to help ensure consistent studies with uniform indicators in future studies related to pelvic correction. Methods : The following keywords "골반", "골반 교정", "골반 변위" "Pelvic correction" were searched on three specialized search sites (RISS, NAI, DBpia). Trends in pelvic correction therapy were analyzed through the selected researches suitable among these searched researches in an overview format. Results : 1. A total of 7,806 studies were searched and a total of 268 studies were finally selected. 2. Studies began in 1977 and have been actively studied until recently, with 35 studies in 2017 being the most recent trend since 2000. 3. In the results according to the Main Field of Research, the 'Arts and Kinesiology'(113, 42.16%) and 'Medicine and Pharmacy'(103, 38.43%) were the most in order. To the Middle Field, the 'Kinesiology was the largest with 96(35.82%) studies. 4. In the results according to the study design, 'Pre-Post Test(PPT)' was the largest with 107 studies. 5. In the results according to the Intervention, 'Exercise' was the largest with 165 studies, of which 'Pilates' and 'Yoga' in 'Training' was the largest. 6. Among the evaluation method, the 'Pelvic Index' was used 146 times, followed by 'Spinal Alignment (99)', 'Other Joints (93)', and 'Kinetic Specialized Measurement Test (56)'. 7. Among the evaluation methods, the pelvic slope measurement indicators were PT (58), PH (48), Pelvic Torsion (40), Iliac Crest (38), ASIS-PSIS distance/angle (27), and Pelvic Width (I.W., I.L., S.W) (25) in order. 8. The journals that published the most researches were KJSS(Korean Alliance For Health, Physical Education, Recreation, And Dance;9), and JKPT(Korean Physical Therapy;9). Among the University, the Graduate School of Silla University published the most papers (12). 9. The author who published the most studies were Seungjin Park(3), the co-authors were Hoseong Lee, Gideok Park, Seongsu Bae(3), and the Thesis-Director Gyeongok Lee(7). Conclusions : 1. Studies on pelvic correction treatment continue to increase every year. 2. The main academic field of pelvic correction is 'Sports', 'Physical Therapy', and 'Medical Science'. 3. The most chosen research design method in the study on pelvic correction treatment was 'Pre-Post Test(PPT)', primarily as an intermediary, Pilates and yoga during exercise therapy, and then Chiropractic during handcraft were used as multiple frequencies. 4. Among the various measurement method indicators of pelvic correction previously used, multiple frequency was taken up in the order of PT, PH, Pelvic Torsion, iliac crest, ASIS-PSIS distance/angle, and pelvic width (I.W.,I.L.,S.W). Typically, measurements through "ASIS-PSIS angle" are recommended and are considered as the most rational in clinical trials.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.4
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• pp.395-401
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• 2010

The vertical members of structures are shortened as time goes on. Because structures have been high-rising and atypical there should be different axial loads among vertical members and it causes differential column shortenings. The differential column shortening add stresses to connections, make slab tilt, and damage to non-structural components. To reduce these influences compensation is need. The rational compensation means the exact expectation of amounts of column shortenings and the reasonable corrections. The expectation of column shortenings are more exact as researched, however, there is little research about the compensation. This paper presents the average correction method and the constraints for differential column shortenings considering errors due to the construction precision. The relations between constraints and the number of correction groups give an objective criterion for decision of constraints.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.543-554
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• 2013

Acoustic Doppler Current Profilers (ADCPs) are increasingly popular in the river research and management communities being primarily used for estimation of stream flows. ADCPs capabilities, however, entail additional features that are not fully explored, such as morphological representation of river or reservoir bed based upon multi-beam depth measurements. In addition to flow velocity, ADCP measurements include river bathymetry information through the depth measurements acquired in individual 4 or 5 beams with a given oblique angle. Such sounding capability indicates that multi-beam ADCPs can be utilized as an efficient depth-sounder to be more capable than the conventional single-beam eco-sounders. The paper introduces the post-processing algorithms required to deal with raw ADCP bathymetry measurements including the following aspects: a) correcting the individual beam depths for tilt (pitch and roll); b) filtering outliers using SMART filters; d) transforming the corrected depths into geographical coordinates by UTM conversion; and, e) tag the beam detecting locations with the concurrent GPS information; f) spatial representation in a GIS package. The developed algorithms are applied for the ADCP bathymetric dataset acquired from Han-Cheon in Jeju Island to validate themselves applicability.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.231-235
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• 2011

In these day, the number of people who have an abnormal posture caused by bad habit are increasing. Therefore, people suffer various disease and symptoms. For correcting the posture to cure, we need continuous monitor, expenditure of time and money. In this study, we develop a posture correcting aid system in other to monitor a posture continuously and leads to pose correctly and records postural variation which are attached to the neck and the waist. The devised system showed good potential for the correct posture guide and a cure of postural defect.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.64-66
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• 2004

When examing patients with DRs it is necessary to remove bad pixels and lines and to correct non-uniform offsets and x-ray field. For non-uniformity correction a flat field x-ray image is needed, and to obtain it the center of detector is usually aligned with the focal spot of the x-ray tube, which is conserved when examing patients to preserve the flat field. In some of radiographic techniques, however, it is necessary to move the x-ray tube off the center position of detector or tilt the detector. We investigated the effect of detector tilting on the non-uniformity correction, and propose a method to reduce the effect using a new algorithm. The flat field of X-ray in the DR detector could be guaranteed with this result.

• The Journal of Korea Robotics Society
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• v.3 no.2
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• pp.99-105
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• 2008

To achieve autonomous mobile robot navigation, accurate localization technique is the fundamental issue that should be addressed. In augmented reality, the position of a user is required for location-based services. This paper presents indoor localization using infrared reflective artificial landmarks. In order to minimize the disturbance to the user and to provide the ease of installation, the passive landmarks are used. The landmarks are made of coated film which reflects the infrared light efficiently. Infrared light is not visible, but the camera can capture the reflected infrared light. Once the artificial landmark is identified, the camera's relative position/orientation is estimated with respect to the landmark. In order to reduce the number of the required artificial landmarks for a given environment, the pan/tilt mechanism is developed together with the distortion correction algorithm.