• 한국멀티미디어학회논문지
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• 제21권2호
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• pp.181-187
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• 2018

Line-laser beams are used for depth measurement of welding beads along the circumference of a pipe. For this, first we project a line-laser beam on an rotating pipe and take a sequence of images of the beam projected on the pipe using a CCD camera. Second, the projected line laser beam in each image is detected, converted into a thin curve. Finally measure the distance between the thinned curve and an imaginary line. When a line-laser beam is projected to a rough metal surface such as arc welding beads, the beam is severely scattered. This severe scattering makes the thinned curve perturbed. In this paper, we propose a thinning method robust against scattering of line lasers. First, we extract a projected line laser beam region using an adaptive threshold. Second, we model a thinned curve with a spline curve with control points. Next, we adjust the control points to fit the curve to the projected line-laser beam. Finally, we take a weighted mean of thin curves on a sequence of image frames. Experiments shows that the proposed thinning method results in a thinning curve, which is smooth and fit to the projected line-laser beam with small error.

• 대한물리치료과학회지
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• 제3권4호
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• pp.207-214
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• 1996

Main cause of low back pain is a poor posture. Most low back pains are due to a poor posture. The poor posture induces muscle tension and finaliy low back pain. The poor posture arehabitually trained from the childhood by the environmetal factors. In general, maintaining good posture during working and sleeping hours are the first line of defence against back pam. (1) Supine posture is the easiest posture that relaxes and fixes muscles. Supine posture is thus a starting position for on exercise. Lying down releases the weight pressures of head and shoulder and thus body can be relaxed and extended which are helpful for treating back pain. However, supine posture can increase the pressure in ribcage posture aspect and disphragram due to visceral oragans. (2) Sitting in one position for a long time results in fatigue and relaxation of spinal muscies. Finally, body strength is weakened and sitting posture will become poor. If this poor posture continues for a longer time, pain will be accompanied due to overelongation of muscle ligaments. The habitual poor posture could induce intervertebral disc distortion. If the intervertebral disc is damaged, sitting in one position or movement causes pain. (3) Abnormal lumbar curve induces the tention of abdominal muscle and paravertebral muscle groups as well as tention of lower limb muscle group connected to pelvis. For a person with weak body strength, muscle relaxation increases curvature in lumbar, chest and cervical regions. This will induce a pelvic anterior tilting of the imaginary line between A. S. I. S. and P. S. I. S. Hip joint extensor muscle acts on releasing the pelvic anterior tilting. Contrections of hamstring muscle and femoral muscle recover the imaginary line between A.S.LS. and P.S.I.S. from pelvic anterior tilting. thus, contraction of rectus abdominis muscle are required to maintain the normal lumbar curve.

• International Journal of Precision Engineering and Manufacturing
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• 제6권3호
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• pp.24-28
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• 2005

Stress state of chip formation zone is one of the main problems in metal cutting mechanics. In two-dimensional case this process is usually considered as consistent shears of work material along one of several shear surfaces, separating chip from workpiece. These shear planes are assumed to be trajectories of maximum shear stress forming corresponding slip-line field. This paper suggests a new approach to the constriction of slip-line field, which implies uniform compression in chip formation zone. Based on the given model it has been found that imaginary shear line in orthogonal cutting is close to the trajectory of maximum normal stress and the problem about its determination has been considered as well. It has been shown that there is a second central slip-line field inside chip, which corresponds well to experimental data about stress distribution on tool rake face and tool-chip contact length. The suggested model would be useful in understanding mechanistic problems in machining.

• Journal of Information Technology Applications and Management
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• 제28권3호
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• pp.77-87
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• 2021

The color gray in the cinema expresses the private or public memory and oblivion in the reminiscence scenes. The aesthetic function and meaning of gray that interacts with other elements in cinematic time and space are expanded in various ways. This study was analyzed the cases in which gray was used as the main visual style by limiting the scope to Korean films. Based on the traditional cultural symbolic meaning of gray, I analyzed how it was applied and transformed in films, and interpreted the cultural-social meaning by the interaction between gray and other elements. In film history starting from monochrome, gray has been used as a visual device suitable for realizing cinematic or imaginary reality. Gray is adopted when dreams or recollections are visualized as imaginary reality, and it is used when dreamy imaginations of daydreaming are demonstrated. Gray, which reproduces the dreamlike reality of imagination, is the concrete and realistic way of expression. First, in Korean films, gray is a flashback visual device that recalls the past, and is an intermediary visual form that materializes the imaginary. In films such as Ode to My Father (2014), DongJu (2015), A Resistance(2019) and The Battle : Roar to Victory (2019), the gray of the past is a visual device for cultural memory that builds the homogeneity and identity of the group. In the era of hyper-visibility, gray in black and white images is intended to be clearly remembered by unfamiliarity rather than blurry oblivion by familiarity. Second, in genre films with disaster materials such as Train To Busan (2016) and Ashfall (2019), the grays of rain, fog, clouds, shadows and smoke highlight other elements, and the gray color causes anxiety and fear. In war films such as TaeGukGi: Brotherhood Of War (2003) and The Front Line (2011), gray shows a more intense brutality than the primary color. In sports films such as 4th Place (2015), Take Off (2009) and Forever The Moment (2007), gray expresses uncertainty and immaturity. Third, gray visualizes the historical memory of A Petal (1996), the oblivion in Oh! My Gran (2020) and Poetry (2010), and the reality of daydreaming Gagman (1988) and Dream (1990). At the boundary between imagination and reality, gray is a visual form of dreams, memories and forgetfulness.

• 방송공학회논문지
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• 제12권1호
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• pp.28-40
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• 2007

본 논문에서는 기존에 제안된 잔향 알고리즘 구조에서 문제점으로 대두된 잔향특성을 개선한 새로운 알고리즘 구조를 제안하였다. 제안된 알고리즘 구조는 초기 잔향을 위하여 탭 지연라인을 사용하여 초기반사음을 충분히 구현하였고, 후기 반사음과 잔향을 위해 nested allpass delay line을 이용하여 잔향 밀도를 높이도록 제안하였다. 실내음향의 파라메터를 추출하여 각 지연 라인의 지연 시간을 설정 및 조절하여 가장 좋은 잔향 효과를 갖도록 계수 값들을 설정하였으며, 제안한 알고리즘을 일반 범용 신호처리기를 이용하여 구현 및 실험 고찰을 통해 기존에 제시된 모델에서의 임펄스성음에 대한 비선형적인 거친 응답과 급격한 음색변화가 감소하여, 고르고 평탄한 잔향 밀도가 향상되어 잔향특성이 개선됨을 관찰하였다.

• 대한의용생체공학회:의공학회지
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• 제32권1호
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• pp.15-24
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• 2011

While Compton imaging is recognized as a valuable 3-D technique in nuclear medicine, reconstructing an image from Compton scattered data has been of a difficult problem due to its computational complexity. The most complex and time-consuming computation in Compton camera reconstruction is to perform the conical projection and backprojection operations. To alleviate the computational burden imposed by these operations, we investigate a rebinning method which can convert conical projections into parallel projections. The use of parallel projections allows to directly apply the existing deterministic reconstruction methods, which have been useful for conventional emission tomography, to Compton camera reconstruction. To convert conical projections into parallel projections, a cone surface is sampled with a number of lines. Each line is projected onto an imaginary plane that is mostly perpendicular to the line. The projection data rebinned in each imaginary plane can then be treated as the standard parallel projection data. To validate the rebinning method, we tested with the representative deterministic algorithms, such as the filtered backprojection method and the algebraic reconstruction technique. Our experimental results indicate that the rebinning method can be useful when the direct application of existing deterministic methods is needed for Compton camera reconstruction.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 봄 학술발표회 논문집
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• pp.118-125
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• 1992

The ground deformation due to the tunnel excavation is dependent on various factors such as ground condition, geometry of the tunnel, excavation method, installation of support members, construction condition of each excavation stage, etc. And the distance from the facing effects significantly the stress conditions of the supported and unsupported ground due to the 3-dimensional structural nature of the excavated tunnel. The concept of ground characteristic line has been applied to properly consider the loading condition given by staged tunnel excavation so that the imaginary supporting pressure is applied against the surface of excavated ground. Discussions on the results of the performed finite element analysis were mainly made with respect to the ground settlement, tunnel displacement, earth pressure, stress mobilized in supporting members.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.48-57
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• 2005

Discrete Event Simulation은 기존에 생산 분야에서 적용되어지는 이론중의 하나로 생산에서 발생되는 작업을 Event 기반으로 분류하고 각각의 경우를 기초로 Simulation하여 평가하는 기법이다. 철도차량의 중정비는 핵심부품의 정비를 단계별로 세분화하여 이루어지는데 틸팅차량을 포함하는 신형 철도차량의 경우 주요 정비부품이 많은 제어장치와 전자장치로 구성되어 있다 대차의 경우 많은 주요부품이 중복되어 이것을 체계적이며 효율적으로 유지 보수하는 것이 절실한 것이다. 이러한 부품의 상태를 점검하고 평가하는 것은 유지보수에 관련된 인력이 아닌 이와 관련된 분석기계일 것이고 틸팅차량의 경우 다량의 주요 부품에 대한 유지보수기계의 성능의 평가가 요구될 것이다. 본 논문은 이러한 필요성에 기초하여 작성되었다. 우선 Discrete Event Simulation의 개념을 간략히 소개하였고 Discrete Event Simulation의 5단계 알고리즘을 철도차량 유지보수기계 기반으로 수정하였다 그리고 유지보수 요구 조건에 기초하여 Simulation 알고리즘을 적용하였다. 본 논문은 Discrete Event Simulation의 이론을 이전에 적용된 사례가 없는 철도차량유지보수 분야에 소개하여 유지보수 효율의 극대화를 위한 기법을 적용하였으며 향후 철도차량 유지보수관련 기계의 성능 평가 및 적용에 있어 도움이 될 수 있는 참고 자료로 활용 가능할 것이다.

• 대한전기학회논문지:전력기술부문A
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• 제52권2호
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• pp.121-133
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• 2003

This paper presents a fault location algorithm for a single phase-to-ground fault on 3-terminal transmission systems. The method uses only the local end voltage and current signals. Other currents used for the algorithm are estimated by current distribution factors and the local end current. Negative sequence current is used to remove the effect of load current. Five distance equations based on Kirchhoff's voltage law are established for the location algorithm which can be applied to a parallel transmission line having a teed circuit. Separating the real and imaginary parts of each distance equation, final nonlinear equations that are functions of the fault location can be obtained. The Newton-Raphson method is then applied to calculate the estimated fault location. Among the solutions, a correct fault distance is selected by the conditions of the existence of solution. With the results of extensive S/W and H/W simulation tests, it was verified that the proposed algorithm can estimate an accurate fault distance in a 154kV model system.

• International Journal of Costume and Fashion
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• 제8권2호
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• pp.50-64
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• 2008

The purpose of this study is to classify Avatar fashion style through analysis of on-line Avatar Mall and to propose color pallette and fashion contents from fashion color analysis. The literature research focused on investigating the notion, characters and types of Avatar and relation of Avatar and self-image, clothing image and color image. In data research, 4 on-line portal sites Avatar Malls were analyzed and Avatar fashion style was classified. In addition, Avatar clothing color was analyzed. The research of this study are as follows: Firstly, Avatar in the cyber space represents 'me' of the real states. Avatar fashion helps to represent Avatar Image and clothing makes human image and identity as a social sign. Color helps to constitute clothing impression and human image, therefore clothing and color are the important elements to express self-image through Avatar in the cyber space. Secondly, Avatar Malls of 4 on-line portal sites are very similar and confuse Avatar users because of no standard of fashion style classification. Accordingly, the standard of fashion style classification should be made by a fashion expert, and the specific characters of every on-line portal site should be emphasized. Thirdly, as a result of the analysis of Avatar's clothing, the clothing is divided into a real world clothing and an imaginary world clothing. There are daily clothes, uniform, event clothes, story clothes and fantasy clothes. As a result of the color analysis of Avatar clothing, White, Red, Red Purple colors and bright and vivid tone are generally used for Avatar clothing. This study is significant to classify Avatar fashion style systematically, to notify sensitive and delicate users' sign and to make Avatar fashion image emotional and high-quality.