• Progress in Medical Physics
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• v.21 no.1
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• pp.113-119
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• 2010

Software for GafChromic EBT2 film dosimetry was developed in this study. The software provides film calibration functions based on color channels, which are categorized depending on the colors red, green, blue, and gray. Evaluations of the correction effects for light scattering of a flat-bed scanner and thickness differences of the active layer are available. Dosimetric results from EBT2 films can be compared with those from the treatment planning system ECLIPSE or the two-dimensional ionization chamber array MatriXX. Dose verification using EBT2 films is implemented by carrying out the following procedures: file import, noise filtering, background correction and active layer correction, dose calculation, and evaluation. The relative and absolute background corrections are selectively applied. The calibration results and fitting equation for the sensitometric curve are exported to files. After two different types of dose matrixes are aligned through the interpolation of spatial pixel spacing, interactive translation, and rotation, profiles and isodose curves are compared. In addition, the gamma index and gamma histogram are analyzed according to the determined criteria of distance-to-agreement and dose difference. The performance evaluations were achieved by dose verification in the $60^{\circ}$-enhanced dynamic wedged field and intensity-modulated (IM) beams for prostate cancer. All pass ratios for the two types of tests showed more than 99% in the evaluation, and a gamma histogram with 3 mm and 3% criteria was used. The software was developed for use in routine periodic quality assurance and complex IM beam verification. It can also be used as a dedicated radiochromic film software tool for analyzing dose distribution.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1048-1054
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• 2011

Laser surface hardening process is the method of hardening surface by inducing rapid self quenching of laser injected area through transfer of surface heat to inside after rapid heating of laser injected area only by high density energy heat source. This surface treatment method does not involve virtually any thermal deformation by heat treatment nor accompanies any other process after surface hardening treatment. In addition, allowing local machining, this method is a surface treatment method suitable for die with complicated shape. In this study, die material cast iron was surface-treated by using high power diode laser with beam profile suitable for heat treatment. Since the shapes of die differ by press die process, specimens were heat-treated separately on plane and corner depending on the applied parts. At this time, corner heat treatment was done with optic head inclined at $10^{\circ}$. As a result, corner heat treatment easily involves concentration of heat input due to limitation of heat transfer route by the shapes compared with plane part, so the treatment accomplished hardening at faster conveying speed than plane heat treatment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1123-1129
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• 2003

The noise of maneuvering submarines or vessels can be divided into the tonal signals and broadband ambient noise. Tonal signals are from the revolution of motors and engines of vessels, and broadband ambient noise is from the bubbles which are generated by the propellers and the flow of water around vessels. We can analyze the kinds and the speed of vessels if we analyze the tonal signals and ambient noise. But, it is difficult to divide the tonal signals form the ambient noise when the power of tonal signal is much weaker than the power of ambient noise. In this paper, we detect the direction of arrival(DOA) of the noises generated by vessels with the automatic tracking window(ATW) preprocessing algorithm, and make a beam to the direction of the targets. We suggest a method which can separate weak tonal signals from broadband ambient noise with the ATW algorithm.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.219-225
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• 2007

컴퓨터교과는 학생들의 일반적인 학업성취 개인차 요인과 더불어 필수 교과가 아니기 때문에 학교 혹은 교사마다 교육하는 내용이 상이하여 학생들이 상급학교로 진학하였을 때 학생들 간의 수준 차가 심화된다. 이러한 다양한 수준차가 있는 학생들을 교사 1인이 한정된 시간 안에 모든 학생들의 수준에 맞추어 지도하는 것은 대단히 어렵다. 또 넓은 컴퓨터실에서는 학생들의 주위가 분산될 우려가 많으므로 학생들의 행동을 수시로 관리할 필요가 있다. 이러한 컴퓨터교과 실습수업 시에는 보다 효과적인 지도방법이 요구된다. 이에 본 연구에서는 컴퓨터교과 실습지도 방법의 장단점을 분석하고, 컴퓨터교과 실습수업 시 널리 사용되는 시범 실습법의 단점을 보완할 수 있는 도우미학생 활용 시범 실습법을 제안하고, 중학교 컴퓨터 정규교과 시간에 적용하여 그 효과를 검증하였다. 도우미학생 활용 시범 실습법이란 교사는 실습내용을 설명하고, 모든 학생들은 교사의 설명과 동시에 실습을 하며, 도우미학생의 실습내용이 빔 프로젝트를 통해 다른 학생들에게 보여짐으로써 교사의 시범을 대신하는 방법을 말한다. 컴퓨터교과는 설명만으로도 실습 가능한 내용이 많아 이러한 지도방법이 가능하다 이 방법은 실습내용을 최소한의 작은 단계로 구분하고, 각 단계별로 교사의 설명과 개별지도, 모든 학생의 실습과 관찰이 동시에 이루어진다. 이 방법은 교사의 행동이 자유로워 설명과 동시에 개별지도가 가능해 개별지도의 확대를 가져올 수 있으며, 학생들에게 보다 많은 즉각적인 피드백을 줄 수 있으며, 학생들의 행동을 수시로 관리할 수 있다는 장점이 있다. 또한 본 연구에서는 검증도구로 'html 태그' 단원 5차시 분량의 과제수행능력평가도구를 개발하여 사용하였다. 검증결과 학업성취 중하수준의 도우미학생 활용 시범 실습으로 수업한 집단은 통제반과 유의미한 차이가 없었으나, 학업성취 중상수준의 도우미학생 활용 시범실습으로 수업한 집단은 통제반에 비해 과제수행능력에 있어서 유의미한 차이를 보였다 이로써 제안한 지도방법의 효과성을 입증하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1719-1730
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• 2013

Recently BIM technology has been expanded for using in construction project. However its spread has been delayed than the initial expectations, due to the high-cost of BIM infrastructure development, the lack of regulations, the lack of process and so forth. Therefore, this research proposes the cloud computing based BIM service for saving the cost of BIM infrastructure development and providing various BIM Services to meet the domestic process. In order to achieve this, we perform a survey on the cloud computing based BIM service and develope the prototype system as the core technology of proposed service. The developed the prototype system consists of the IFC based BIM server for IaaS (Infrastructure as a Service) and the viewer for SaaS (Software as a Service). This research also conducts the performance test for their applicability and verifies that the results of this research can be used as core components in the cloud computing based BIM service.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.93-102
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• 2011

This paper presents a walking guidance system for blind pedestrians in an outdoor environment using just one single camera. Unlike many existing travel-aid systems that rely on stereo-vision, the proposed system aims to get necessary information of the road environment by using just single camera fixed at the belly of the user. To achieve this goal, a top-view image of the road is used, on which obstacles are detected by first extracting local extreme points and then verified by the polar edge histogram. Meanwhile, user motion is estimated by using optical flow in an area close to the user. Based on these information extracted from image domain, an audio message generation scheme is proposed to deliver guidance instructions via synthetic voice to the blind user. Experiments with several sidewalk video-clips show that the proposed walking guidance system is able to provide useful guidance instructions under certain sidewalk environments.

• 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 Institute of Electronics Engineers of Korea SP
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• v.45 no.2
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• pp.29-36
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• 2008

In this paper we propose a real-time method to estimate a pointing region from two camera images. In general, a pointing target exists in the face direction when a human points to something. Therefore, we regard the direction of pointing as the straight line that connects the face position with the fingertip position. First, the method extracts two points in the face and the fingertips region by using detecting the skin color of human being. And we used the 3D geometric information to obtain a pointing detection and its region. In order to evaluate the performance, we have build up an ICIGS(Interactive Cinema Information Guiding System) with two camera and a beam project.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.523-532
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• 2013

Since conventional methods for the reconstruction of 3D objects used a number of cameras or pictures, they required specific hardwares or they were sensitive to the photography environment with a lot of processing time. In this paper, we propose a 3D object reconstruction method using one photograph based on structured light in ubiquitous environments. We use color pattern of the conventional method for structured light. In this paper, we propose a novel pipeline consisting of various image processing techniques for line pattern extraction and matching, which are very important for the performance of the object reconstruction. And we propose the optimal cost function for the pattern matching. Using our method, it is possible to reconstruct a 3D object with efficient computation and easy setting in ubiquitous or mobile environments, for example, a smartphone with a subminiature projector like Galaxy Beam.

• Journal of Korea Multimedia Society
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• v.13 no.10
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• pp.1547-1556
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• 2010

Until now, many Computer Aided Education(CAE) contents are developed for kids and children with disabilities The contents cover various types of training, including visual perception training, intelligence development training, and literature education areas. Major problems on those contents are those contents requires long training time on desktop machine, which deteriorates human activities. These problems also cause inaction syndrome for young kids and children with disabilities. Solving this problem, we require a human motion sensing contents on touch screen or touch board, which interacts with a trainees and enhancing activity, collaboration and immersiveness. We implement and develope an education contents interacts with a trainee using beam projector or screen and IR(Infra-Red) pens using wiimote controller sensing technology.