• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.45-52
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• 2015

The purpose of this study was to compare and evaluate facemask effects when two types of intraoral appliances were used for maxillary protraction for patients with class III malocclusion. Eighteen patients with class III malocclusion were treated with a facemask for an average of 12 months. Two types of intraoral appliances were used: nine patients were treated with bonded expander (Group 1), and nine patients with Hyrax (Group 2). Cephalometric radiographs were taken before and after treatment. Cephalometric radiographs were traced, analyzed, and the results such as sagittal, vertical and soft-tissue changes were compared between two groups. The amount of anchorage loss was also measured to evaluate the difference between two groups. All patients showed significant sagittal skeletal changes after treatment, and there was no statistically significant difference between the two groups. When anchorage loss was evaluated, no differences were shown between the two. Facemask with Hyrax or bonded expander is similarly an effective method as a treatment in class III malocclusion patients.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.133-138
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• 2022

Digital radiation inspection equipment is a medical device that deals with human life and requires stability and high reliability. However, this system is currently the most advanced technology and the domestic market is almost occupied by European products including Japan. Therefore, research and development are needed not only to replace domestic medical devices, which are largely dependent on expensive imported products, but also to develop more economical and user-oriented products that are easy to operate and produce devices that lead to accurate diagnosis. In particular, among the digital X-ray systems, the motor driving technology and the mechatronics technology related to the development of mechanical devices have matured to some extent in Korea. In this paper, selection of AC servomotor for digital radiation inspection suitable for imaging purpose, and application of conversion device and control method to check performance and improve problems.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.123-124
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• 2011

반도체 기술의 비약적 발전에 힘입어 현재의 개인용 컴퓨터는 고성능 CPU를 탑재하고 1990대의 텍스트 기반의 운영체제에서 벗어나 그래픽 기반의 운영체제에서 다양한 멀티미디어 기능을 제공 한다. 이를 위한 입력장치로 텍스트 기반 운영체제에서 주로 사용된 키보드뿐 아니라 마우스, 카메라, 터치스크린 등의 다양한 장치들이 사용되고 있다. 그러나 빔 프로젝터를 이용한 프레젠테이션의 경우 아직도 레이저포인터를 이용한 발표가 일반적이며 발표자와 빔 프로젝트용 PC와의 인터랙션이 없기 때문에 다양한 멀티미디어 기능 구현이 제한적이다. 본 논문에서는 USB 웹 카메라를 이용하여 프로젝터 화면을 촬영한 후 영상처리 라이브러리인 OpenCV를 기반으로 레이저 포인터의 위치와 동작을 검출하여 원거리에서도 사용자가 레이저 포인터를 이용하여 마우스 동작을 재현할 수 있는 시스템을 개발하고자 한다. 이를 활용하면 레이저 포인터를 사용하여 발표자가 별도의 입력장치 없이 PC와의 인터랙션이 가능해져서 다양한 멀티미디어 기반의 프레젠테이션이 가능해진다.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.10-18
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• 2019

In this paper, we present the results of a developed LTE/Wi-Fi-based video transmission system which can be applied in small unmanned aerial vehicles of 25kg or less. The developed video transmission system comprised of airborne datalink terminal, ground datalink terminal, and used LTE and Wi-Fi wireless data communication technologies to transmit videos of resolution higher than HD (720p/30fps, 1080p/30fps) taken by small UAV. The airborne device is designed to efficiently transmit real-time streaming video through the incorporation of H.264 video processing board. Ground tests and evaluation indicated the possibility of the developed system to transmit real-time videos from close distance in regards to non-line-of-sight area.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.651-662
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• 2023

In this study, we designed and fabricated an ultra-compact CT that automatically calibrates the detector's center axis and verified its performance. The three-dimensional reconstruction performance was evaluated using 3D CAD data and X-ray data acquired by manually calibrating the center axis of the CT detector. The results showed that tilting the center axis by more than 0.25° causes circle break phenomenon, which rapidly degrades the quality of the 3D reconstructed image. By applying the automatic calibration device of a detector center axis, the 3D reconstruction performance was enhanced by calibrating the detector center axis to match the specimen rotation axis.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.322-331
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• 2009

In clinical SPECT, FWHM provides quality information of the images obtained under different observing conditions. Therefore, the purpose of this study was to determine the optimum cut off level with comparison of FWHM according to cut off levels in each filter - Band limited, Sheep-Logan, Hanning, Hamming, Low pass cosine, Parazen and Butterworth filter in a SPECT camera. I recorded images along the X, Y, Z-axis with 99mTcO4 point source and measured FWHM with profile curves. In conclusion, all filters showed the longest figures of FWHM with cut off level 0.4, which has the worst image resolution. The images with cut off level 0.7 showed best image resolution. The shortest average of FWHM in MS2 was $11.07\pm0.07mm$ using the Butterworth filter, in MS3 it was $8.44\pm0.19mm$ through using the Hanning filter.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.2 s.308
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• pp.48-56
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• 2006

This paper introduces design and implementation of digital photo kiosk system, digital photo printing system, with auto color correction module that considers gamut between touch screen and output device, digital photo printer, to provide user-preferred media. This module performs media correction function to service high quality contents for image captured by digital camera and mobile phone camera. Since it is implemented as LUT for real-time processing, the system offers one-touch interface to user. As a result of implementation, this kiosk system provides user-favorite photo because of black and white mode, sepia mode, and brightness and contrast adjustment. Also it can gives smooth tone transition and photos of similar color to captured image due to auto color correction module.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.85-91
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• 2018

Computed tomography, which obtains section images from reconstruction process using projection images, has been applied to various fields. The spatial resolution of the reconstructed image depends on the device used in CT system, the object, and the reconstruction process. In this paper, we investigates the effect of the number of projection images and the pixel size of the detector on the spatial resolution of the reconstructed image under the parallel beam geometry. The reconstruction program was written in Visual C++, and the matrix size of the reconstructed image was $512{\times}512$. The numerical bar phantom was constructed and the Min-Max method was introduced to evaluate the spatial resolution on the reconstructed image. When the number of projections used in reconstruction process was small, artifact like streak appeared and Min-Max was also low. The Min-Max showed upper saturation when the number of projections is increased. If the pixel size of the detector is reduced to 50% of the pixel size of the reconstructed image, the reconstructed image was perfectly recovered as the original phantom and the Min-Max decreased as increasing the detector pixel size. This study will be useful in determining the detector and the accuracy of rotation stage needed to achieve the spatial resolution required in the CT system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.4
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• pp.279-287
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• 2007

The increased availability of portable, low-cost, high resolution video equipments have resulted in a rapid growth of the applications for video sequences. These video devices can be mounted in handhold unit, mobile unit and airborne platforms like maned or unmaned helicopter, plane, airship, etc. This paper describes the feasibility fur generating image map from the experimental results we designed to track the interested points extracted by KLT operator in the neighboring frames and implement image matching for each frames taken from UAV (Unmaned Aerial Vehicle). In the image registration for neighbourhood frames of aerial video, the results demonstrate the successful rate of matching slightly decreases as the drift between frames increases, and also that the stable photographing is more important matching condition than the pixel shift.

• Journal of radiological science and technology
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• v.46 no.5
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• pp.395-399
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• 2023

The knee arthritis patients are generally performed standing position radiography. However, patients with pain caused by degenerative diseases or injuries in the knee have difficulty maintaining a standing position. Therefore, this study aims to develop a knee joint standing weight bearing projection assist device to solve these problems when patients undergo knee radiography due to various diseases. The design of the knee joint weight-bearing radiography assist device is carried out with 3D design and drawing production to secure basic data, electric support and frame manufacture. A fixed device for maintaining the patient's knee standing weight-bearing projection, an electric digital height device, a digital protractor, and a safety device were designed. The arm support is made of PVC with a cushion to relieve the impact and make it easier to remove debris. The digital electric device can be moved up and down according to the patient's height, and a remote control is attached. The safety device is made to be adjustable in size by attaching metal hooks on both sides of the frame and to shield the scrotum. A digital protractor was attached to the side frame to set the desired knee angle. When a self-made assist device was used to perform a knee joint standing weight bearing projection, it helped maintain arm support and lower extremities position. In addition, the height could be adjusted using an assist device during standing projections, which helped the patient maintain the position.