• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집B
• /
• pp.404-409
• /
• 2000

Characteristics of secondary vortices is topologically investigated in the near-wake region of a circular cylinder where the Taylor hypothesis does not hold. The three-dimensional flow fields in the wake-transition regime were measured by a time-resolved PIV. For the analysis in a moving frame of reference, the convection velocity of the Karman vortices is evaluated from the trajectory of vortex center which is defined as the centroid of the vorticity field. Then, a saddle point is obtained by applying the critical point theory. Science the distributions of fluctuating Reynolds stresses defined by triple-decomposition are closely related with the existence of secondary vortices. the physical meaning of them is explained in conjunction with vortex center and saddle point trajectories. Finally, the temporal evolution of streamwise vortex is also discussed.

• Nonlinear Functional Analysis and Applications
• /
• 제26권1호
• /
• pp.137-155
• /
• 2021

In this paper, first, we prove some common fixed point theorems for the generalized contraction condition under newly defined modified simulation function which generalize and include many results in the literature. Second, we give two numerical examples with graphical representations for verifying the proposed results. Third, we discuss and study a set of common fixed point theorems for two pairs (finite families) of self-mappings. Finally, we give some applications of our results in discrete and functional fractional economic systems.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2022년도 춘계학술대회
• /
• pp.421-424
• /
• 2022

허프변환은 에지 영상에서 직선을 검출하는 대표적인 알고리즘이다. 허프변환은 에지 화소에서 발생 가능한 직선들의 파라미터들을 파라미터 공간상에 대응시키고, 주어진 조건을 만족하는 유효 파라미터를 직선으로 검출한다. 일반적인 허프변환에서는 직선의 파라미터들은 영상 원점을 기준점으로 계산되고 있다. 그러나 본 논문에서는 영상 중심이 기준점인 허프변환을 수행하고 그 성능을 기존 허프변환과 비교분석하고 있다.

• 복식문화연구
• /
• 제18권6호
• /
• pp.1228-1241
• /
• 2010

This study aims to help understanding on design of basic pattern of shirt collars and to suggest schemes to raise completeness of shape by reviewing problems shown in finished products after sewing. From March 2009 to August 2009, 12 patterns for education and firms were collected centering on basic shirt collar form respectively. There are four problems generally raised from a completed shirt collar. In case of overlapping shirt collar on front neck point, the sewing point of shirt collar should be drawn at front neck point of collar band at a distance of about 0.2~0.3cm, and the center front of band and one of bodice should be arranged in a straight line. In case of the problem about right and left length difference of shirt collar, it is raised by closing so the problem was solved by prolonging about 0.2 cm of the center front of left collar. It was evaluated that adjusting notch point when sewing would be more rational solution than solving something on patterns for distance difference problem of shirt collar between right and left part at center front. And a problem about getting loose of front garment between collar band below and the first button was also raised. It was designed 0.2cm cut of collar band. Around basic shirt collar form, above mentioned solutions are applied to the patterns for education and manufacture experimental clothing. So as a result of sensory evaluation, generally good ratings on all items were received.

• 산업경영시스템학회지
• /
• 제23권60호
• /
• pp.11-22
• /
• 2000

The main objective of this research is to analyze an order point and an order quantity of a distribution center and each branch to attain a target service level in multi-level inventory distribution system. In case of product item, we use the item with low volume of average monthly demand. Under the continuous review method, the distribution center places a particular order quantity to an outside supplier whenever the level of inventory reaches an order point, and receives the order quantity after elapsing a certain lead time. Also, each branch places an order quantity to the distribution center whenever the level of inventory reaches an order point, and receives the quantity after elapsing a particular lead time. When an out of stock condition occurs, we assume that the item is backordered. For considering more realistic situations, we use generic type of probability distribution of lead times. In the variable lead time model, the actually achieved service level is estimated as the expected service level. Therefore, this study focuses on the analysis of deciding the optimal order point and order quantity to achieve a target service level at each depot as a expected service level, while the system-wide inventory level is minimized. In addition, we analyze the order level as a maximum level of inventory to suggest more efficient way to develop the low demand item model.

• 한국광학회지
• /
• 제12권2호
• /
• pp.103-108
• /
• 2001

플라즈마 디스플레이 패널(plasma display panel :PDP)에서 방출되는 광의 3차원 분포를 측정하기 위한 scanned point-detecting system(SPDS)을 고안하여 제작하였으며 이 시스템을 이용하여 실제 PDP의 3차원 광 방출 특성을 측정하고 해석하였다. SPDS는 상면에 핀홀이 달려 있는 광검출기(point detector)를 위치시킴으로써 특정 지점으로부터 방출되는 광만을 검출할수 있다. 3차원 물체의 특정 지점으로부터 방출된 광은 핀홀을 지나 검출기로 모두 입사되지만 다른 지점으로부터 방출된 광은 핀홀 앞에서 미리 집속되거나 핀홀 뒤에서 집속될것이므로 이러한 광들은 핀홀에 의해 대부분 차단될 것이다. 그러므로 물체의 특정 지점으로부터 방출된 광만이 핀홀이 설치된 검출기에 의해 검출되어 진다. SPDS를 이용하여 PDP cell 내에서 측정된 3차원 광 intensity 분포로부터 cellso의 방전현상을 다음과 같이 유추해낼수 있었다. Z축 측정이 진행될수록광의 intensity는 증가하였고 ITO전극의 안쪽부분에서 검출되는 광의 intensity가 가장 컸고 Y축 scan시 나타나는 X-Z평면에서 광의 intensity가 격벽과 격벽의 중심부분에서 가장 크게 나타났다.

• 복식문화연구
• /
• 제4권3호
• /
• pp.373-381
• /
• 1996

Draping design system organized by European about 13C has been developed greatly for a long while, but for the purpose of the practical use the Dress form similar to human body has been needed. In order to make three-dimensional effect as fitting Muslin ot the Dress form. the Basic lien has to be established in Muslin and Dress form each. At this time, Shoulder-blade level is indicated from various angles : measure down 10cm from the back neck point, a quarter of the back neck point to the waist lie, the half-way point between neckline and bust line, measure down 41 inches from the back neck line, measure down 3 inches from the top edge of the muslin at center back and cross mark for neck line, and so forth. This study established the Basic line through the two ways of them (B.N.P∼B.L/2, B.N.P∼W.L/4), did tight fitting to the 5 kinds of Dress forms which ar normal type in the drop value(the difference between hip circumference and bust circumference), and acquired Basic Pattern. After the experiment, fitness are throughly investigate by statistical analysis of measurements. As a result, this study finds out that fit is proper when shoulder blade level is situated on a fourth of the back neck point to the waist line and a quarter point between back neck point and waist line, and waist dart is situated on the back center line and princess line.

• Structural Engineering and Mechanics
• /
• 제34권4호
• /
• pp.399-416
• /
• 2010

The purpose of this paper is to utilize the numerical assembly method (NAM) to determine the exact natural frequencies and mode shapes of a multi-step beam carrying multiple rigid bars, with each of the rigid bars possessing its own mass and rotary inertia, fixed to the beam at one point and supported by a translational spring and/or a rotational spring at another point. Where the fixed point of each rigid bar with the beam does not coincide with the center of gravity the rigid bar or the supporting point of the springs. The effects of the distance between the "fixed point" of each rigid bar and its center of gravity (i.e., eccentricity), and the distance between the "fixed point" and each linear spring (i.e., offset) are studied. For a beam carrying multiple various concentrated elements, the magnitude of each lumped mass and stiffness of each linear spring are the well-known key parameters affecting the free vibration characteristics of the (loaded) beam in the existing literature, however, the numerical results of this paper reveal that the eccentricity of each rigid bar and the offset of each linear spring are also the predominant parameters.

• 드라이브 ㆍ 컨트롤
• /
• 제21권2호
• /
• pp.65-71
• /
• 2024

In this study, we suggested a key-point detection method for robot harvesting of oriental melon. Our suggested method could be used to detect the detachment part and major composition of oriental melon. We defined four points (harvesting point, calyx, center, bottom) based on tomato with characteristics similar to those of oriental melon. The evaluation of estimated key-points was conducted by pixel error and PDK (percentage of detected key-point) index. Results showed that the average pixel error was 18.26 ± 16.62 for the x coordinate and 17.74 ± 18.07 for the y coordinate. Considering the resolution of raw images, these pixel errors were not expected to have a serious impact. The PDK score was found to be 89.5% PDK@0.5 on average. It was possible to estimate oriental melon specific key-point. As a result of this research, we believe that the proposed method can contribute to the application of harvesting robot system.

• Kyungpook Mathematical Journal
• /
• 제55권2호
• /
• pp.473-484
• /
• 2015

Archimedes determined the center of gravity of a parabolic section as follows. For a parabolic section between a parabola and any chord AB on the parabola, let us denote by P the point on the parabola where the tangent is parallel to AB and by V the point where the line through P parallel to the axis of the parabola meets the chord AB. Then the center G of gravity of the section lies on PV called the axis of the parabolic section with $PG=\frac{3}{5}PV$. In this paper, we study strictly locally convex plane curves satisfying the above center of gravity properties. As a result, we prove that among strictly locally convex plane curves, those properties characterize parabolas.