• 한국기계가공학회지
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• 제9권1호
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• pp.74-80
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• 2010

The purpose of reverse engineering design using 3D measurement data is an accurate reconstruction of real body. In oder to accomplish this object, it is important that creating exact extracting edges should be studying out first of all. This study used edge-based method to find out edge point from the measuring point data. The characteristics are analysed using the mean curvature block method on the fitting NURBS curve and defined edges through block removal condition. The results showed that only using the NURBS curve of maximum curvature analysis to define correct edge of real geometry is limited, but this segmentation approach provides simplified necessary condition for edge classification, and an effectiveness to classify a straight line, curves and fillets etc.

• 한방재활의학과학회지
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• 제27권1호
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• pp.37-51
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• 2017

Objectives This study was designed to identify the effect of acupuncture combined with wooden neck pillow self-exercise program (WSP). Methods 25 eligible subjects with chronic neck pain were recruited from September 2015 to August 2016. Subjects were treated by acupuncture twice a week for 4 weeks, also were educated WSP and exercised every day for 4 weeks. They were assessed using PI-NRS, NDI and the maximum muscle strength of deep cervical flexor muscles (DCF) before and after treatment. Also the Cobb's angle (C1-C7), Ishihara index, Park method were assessed for evaluating the radiographical changes. Variables were compared using paired t-test. And correlates analysis was used for analyzing relationship between differentials in the maximum muscle strength of DCF and differentials in cervical spine curvature measurement methods. Results Among the 25 subjects, 4 subjects were lost to follow-up or excluded in accordance with the criteria. Significant differences on NRS, NDI and the maximum muscle strength of DCF were seen after treatment (p<0.001). In radiological finding, cervical spine curvature measurement methods were significantly increased (p<0.001, p<0.05, p<0.05). Differentials in the maximum muscle strength of DCF significantly correlates to differentials in Ishihara index (R=0.479, p<0.05). Conclusions Acupuncture combined with WSP may decrease neck pain intensity and associated disability, and also increase the muscle strength of DCF and cervical lordosis, in patients with chronic neck pain. Especially, Improving the muscle strength of DCF has a relationship with improving Ishihara index. However, due to the design of this study, this treatment can not be compared with other treatments. Future randomized project should be needed.

• Journal of Mechanical Science and Technology
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• 제16권9호
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• pp.1121-1136
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• 2002

The flow characteristics of film coolant issuing into turbulent boundary layer developing on a convex surface have been investigated by means of flow visualization and three-dimensional velocity measurement. The Schlieren optical system with a spark light source was adopted to visualize the jet trajectory injected at 35° and 90° inclination angles. A five-hole directional pressure probe was used to measure three-dimensional mean velocity components at the injection angle of 35°. Flow visualization shows that at the 90° injection, the jet flow is greatly changed near the jet exit due to strong interaction with the crossflow. On the other hand, the balance between radial pressure gradient and centrifugal force plays an important role to govern the jet flow at the 35° injection. The velocity measurement shows that at a velocity ratio of 0.5, the curvature stabilizes downstream flow, which results in weakening of the bound vortex structure. However, the injectant flow is separated from the convex wall gradually, and the bound vortex maintains its structure far downstream at a velocity ratio of 1.98 with two pairs of counter rotating vortices.

• 반도체디스플레이기술학회지
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• 제15권4호
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• pp.1-9
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• 2016

The warpage on mobile phone camera packages occurs due to the CTE(Coefficient of Thermal Expansion) mismatch between a thin silicon die and a substrate. The warpage in the optical instruments such as camera module has an effect on the field curvature, which is one of the factors degrading the optical performance and the product yield. In this paper, we studied the effect of die bonding epoxy on the package and optical performance of mobile phone camera packages. We calculated the warpages of camera module packages by using a finite element analysis, and their shapes were in good agreement showing parabolic curvature. We also measured the warpages and through-focus MTF of camera module specimens with experiments. The warpage was improved on an epoxy with low elastic modulus at both finite element analysis and experiment results, and the MTF performance increased accordingly. The results show that die bonding epoxy affects the warpage generated on the image sensor during the packaging process, and this warpage eventually affects the optical performance associated with the field curvature.

• 한국생활과학회지
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• 제14권2호
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• pp.303-312
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• 2005

The purpose of this research is to analyze the lower part of dress forms with different sectional rotation-angles ($e.g.\;9^{\circ},\;15^{\circ},\;30^{\circ},\;45^{\circ}$) using three-dimensional measurement system and to investigate measurement properties for dress making. The dress forms used in this experiment were size 8 and six types: four from Korea and two from Japan. The instrument and tools for three-dimensional measurement was Whole Body 3D scanner (Exyma-WBS2H). The analysis program used in this experiment was Rapid Form 2004 PP1 (INUS technology, Inc, Korea). The measurement of dress forms was done three times with different sectional rotation-angles and its data were analyzed using SPSS WIN 10.0 Package. The following results were obtained: 1. With mean and standard deviation of each measured part, it was found out that the dress forms from two countries were different in size per each part. For example, the Japanese one was relatively large in middle hip and hip, compared to the Korean one. 2. The 3D analysis of the sectional rotation-angles revealed some differences between the two dress forms in sectional length per each part. 3. With cluster analysis results, it was found that there were definite differences among measurements per each part, especially in $30^{\circ}\;and\;45^{\circ}$ sections. 4. The proportion of the dress forms showed significant differences in the curvature between center and side section of the lower parts. In addition, the shapes on the horizontal section map of the four levels (waist, middle hip, hip, and bottom) were analyzed.

• 한국음향학회지
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• 제43권2호
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• pp.168-177
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• 2024

수중 압전 에너지 하베스터(Piezoelectric Energy Harvester, PEH) 설계시 곡률변화를 통해 외팔보형 전체의 와류유기진동(Vortex Induced Vibration, VIV)을 생성시키고, VIV의 생성으로 곡면형 외팔보 PEH에 진동 변위가 증가한다는 것은 실제 전력을 증대 시키는 데 중요한 요소이다. 해석 모델인 곡면형 PEH의 재질은 Polyvinyline Di-Floride(PVDF) 압전 필름으로서 곡률이 다양한 50 mm, 130 mm, 210 mm 모델에 유속은 0.1 m/s ~ 0.50 m/s로 정하여 VIV에 의한 PEH의 스트레인 에너지 변화를 관찰하였다. 곡률 반경이 작을수록 큰 폭의 VIV가 나타났고, 유속이 증가할수록 VIV가 많이 나타났다. 작은 곡률로 인한 급격한 형상변환이 VIV의 생성에 효과적이었고 스트레인 에너지, 정규화 발생 전압, 평균 전력 등은 곡률이 증가할수록 감소하였다. PEH 자체의 전력량을 증대시키기 위해 급한경사의 곡률 개선뿐만 아니라 곡률형 PEH의 개수가 늘어남에 따라 평균 전력도 상승할 것으로 사료된다.

• 제어로봇시스템학회논문지
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• 제10권6호
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• pp.494-500
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• 2004

This paper presents a machine vision system, which inspects the measurement of the ALC block on a real-time basis in the production process. The automatic measurement system was established with a CCD camera, an image grabber, and a personal computer without using assembled measurement equipment. Images obtained by this system was processed by an algorithm, specially designed for an enhanced measurement accuracy. For the realization of the proposed algorithm, a preprocessing method that can be applied to overcome uneven lighting environment, boundary decision method, unit length decision method in uneven condition with rocking objects, and a projection of region using pixel summation are developed. From our experimental results, we could find that the required measurement accuracy specification is sufficiently satisfied by using the proposed method.

• 대한기계학회논문집B
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• 제24권2호
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• pp.188-194
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• 2000

Thermochromic liquid crystal reflect a unique color at even temperature. Therefore, they have been successfully applied to non-intrusive heat transfer research. Hue capturing method is widely used in the quantitative measurement from the TLC image. However it is affected by several measurement conditions. The distances of camera and light source have little influence on the color, but the value of hue is seriously affected by the measurement angle. In this study, the hue capturing method is improved by considering the effect of measurement angle. This improved calibration method can diminish the misreading of temperature caused by curvature of test surface.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.381-382
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• 2009

• 한국전자통신학회논문지
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• 제14권5호
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• pp.871-876
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• 2019

본 논문에서는 플루오린화 수소산(Hydrofluoric acid: HF) 수용액과 광섬유에 인가된 $1.55{\mu}m$ 파장의 레이저를 통해 유도된 광열 효과를 이용하여 오목한 광섬유 팁을 제작하였다. 제작 과정에서 인가한 레이저의 세기, 식각 시간, HF 수용액의 농도에 따른 광섬유 팁 오목 면의 곡률 반경을 광학 현미경을 이용하여 측정하였으며 곡률 반경이 세 변인에 대하여 어떻게 변화하는지 분석하였다. 또한, Free Spectral Range(FSR)와 Scanning electron microscope(SEM) 촬영을 통해 현미경을 이용한 측정 방법의 신뢰성을 검증하였다. 본 논문을 통해 광섬유 팁의 오목 면 제작 과정에서 변인에 따라 곡률 반경을 조절할 수 있게 됨으로써 기존의 HF 수용액을 이용한 광섬유 식각 방법의 한계점을 극복할 수 있었다.