• Journal of Advanced Marine Engineering and Technology
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• 제34권5호
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• pp.711-717
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• 2010

본 논문에서는 플라스틱 평판에 핀 홀을 생성하여 문자나 이미지를 표현하는 디스플레이 보드를 자동으로 제작하는 펀칭시스템을 개발하였다. 핀 홀을 생성한 평판은 가장자리에 설치한 다양한 색상의 발광다이오드 빛을 반사하여 미려한 디스플레이 보드에 사용된다. 펀칭시스템은 정밀한 위치 및 깊이 생성을 위해 총 4개의 엑추에이터를 사용하였다. 디스플레이 보드 상의 글자나 이미지의 반사효과와 빠른 생산성을 위하여 정밀한 구동 기구부를 개발하고 PID 제어 알고리즘을 적용하였다. 그리고 사용자가 반사되는 글자의 모양이나 이미지를 구성하는데 도움을 줄 수 있는 GUI 프로그램과 PC기반의 제어시스템을 구성하였다. 또한 펀칭속도와 생성된 핀 홀의 깊이를 검사하여 본 시스템의 성능을 검증하였다.

• 대한한방소아과학회지
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• 제17권2호
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• pp.1-13
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• 2003

Objectives: The purpose of this study was to suggest a scientific method for measurement of children's growth development. Ultrasonic image of calcaneus bone has some advantages that it is harmless to human body and apply a new imaging analysis algorithm. it can be used for the diagnosis of growth analyzed the opening degree of growth plate and bone density. Methods: This clinical study have been carried out with the 57 case(male 24, female 33) of the children aged 5 to 14 years old who visited in Department of Pediatrics, Dongguk university Bundang Oriental Hospital. Bone maturity is measured by the opening degree of growth plate and bone density in ultrasonic image of calcaneus bone This study were designed to investigate the relationship of the development of children and the calcaneus bone maturity. Result: The opening degree of growth plate was no change in aged 5-10 years for male and 5-9 years for female but decreased significantly from aged 11 years for male and 10 years for female. the bone density was no change in aged 5-12 years for male and 5-11 years for female but increased significantly from aged 13 years for male and 12 years for female. it was confirmed that bone maturity in female is more rapid than in male. The opening degree of growth plate of claclneus bone was correlated with age, height, weight. The bone density was correlated with age, height, weight, BMI in this suudy(P<0.001) Conclusion: The opening degree of growth plate and bone density of calcaneus bone are sufficient diagnostic worth as an index to predict adolescent growth.

• 방송공학회논문지
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• 제19권1호
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• pp.56-63
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• 2014

본 논문은 자동차 번호판 인식을 위한 이진화 과정을 다루고자 한다. 이진화 과정은 번호판 영상을 이진 영상으로 나타내는 것을 말하며, 많은 경우 이진화 결과가 번호판 문자인식 성능에 결정적인 영향을 미치게 된다. 후면 번호판은 전면 번호판과는 달리 구조적 영향에 의해 번호판에 그림자가 생기는 경우가 많은데, 그림자가 있는 번호판은 기존 이진화 방법을 사용할 경우에 적절하지 못한 결과를 가져올 때가 많다. 본 논문에서는 이 같은 문제점을 해결하기 위해 그림자가 있는 번호판에서 그림자가 있는 부분과 그림자가 없는 부분을 구분한 후, 나눠진 영역에 대해 히스토그램 매칭을 수행한다. 히스토그램 매칭된 두 영상을 다시 붙여서 전체 영상에 대해 이진화한다. 그림자가 있는 번호판 이진화를 위한 기존 방법과 성능을 비교 분석하였고, 그림자 경계선 검출에 오차가 있는 경우 제안하는 방법이 기존 방법에 비해 성능이 우수함을 확인할 수 있다.

• Advances in nano research
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• 제16권4호
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• pp.413-426
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• 2024

This paper investigates the dynamic behavior of a simply supported viscoelastic plate made of functionally graded carbon nanotube reinforced composite under dynamic loading. Carbon nanotubes are distributed in 5 different shapes: U, V, A, O and X, depending on the shape they form through the thickness of the plate. The displacement fields are derived in the Laplace domain using a higher-order shear deformation theory. Equations of motion are obtained through the application of the energy method and Hamilton's principle. The resulting equations of motion are solved using Navier's method. Transforming the Laplace domain displacements into the time domain involves Durbin's modified inverse Laplace transform. To validate the accuracy of the developed algorithm, a free vibration analysis is conducted for simply supported plate made of functionally graded carbon nanotube reinforced composite and compared against existing literature. Subsequently, a parametric forced vibration analysis considers the influence of various parameters: volume fractions of carbon nanotubes, their distributions, and ratios of instantaneous value to retardation time in the relaxation function, using a linear standard viscoelastic model. In the forced vibration analysis, the dynamic distributed load applied to functionally graded carbon nanotube reinforced composite viscoelastic plate is obtained in terms of double trigonometric series. The study culminates in an examination of maximum displacement, exploring the effects of different carbon nanotube distributions, volume fractions, and ratios of instantaneous value to retardation times in the relaxation function on the amplitudes of maximum displacements.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.215-216
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.23-24
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• 2008

• Transactions on Electrical and Electronic Materials
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• 제17권6호
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• pp.363-368
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• 2016

Rectangular shape detection plays an important role in many image recognition systems. However, it requires continued research for its improved performance. In this study, we propose a strong rectangular shape detection algorithm, which combines the canny edge and line detection algorithms based on the perpendicularity and parallelism of a rectangle. First, we use the canny edge detection algorithm in order to obtain an image edge map. We then find the edge of the contour by using the connected component and find each edge contour from the edge map by using a DP (douglas-peucker) algorithm, and convert the contour into a polyline segment by using a DP algorithm. Each of the segments is compared with each other to calculate parallelism, whether or not the segment intersects the perpendicularity intersecting corner necessary to detect the rectangular shape. Using the perpendicularity and the parallelism, the four best line segments are selected and whether a determined the rectangular shape about the combination. According to the result of the experiment, the proposed rectangular shape detection algorithm strongly showed the size, location, direction, and color of the various objects. In addition, the proposed algorithm is applied to the license plate detecting and it wants to show the strength of the results.

• 한국전산유체공학회지
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• 제1권1호
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• pp.88-97
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• 1996

This paper treats an adaptive finite-element method for the viscous compressible flow governed by Navier-Stokes equations in two dimensions. The numerical algorithm is the two-step Taylor-Galerkin mettled using unstructured triangular grids. To increase accuracy and stability, combined moving node method and grid refinement method have been used for grid adaption. Validation of the present algorithm has been made by comparing the present computational results with the existing experimental data and other numerical solutions. Four benchmark problems are solved for demonstration of the present numerical approach. They include a subsonic flow over a flat plate, the Carter flat plate problem, a laminar shock-boundary layer interaction. and finally a laminar flow around NACA0012 airfoil at zero angle of attack and free stream Mach number of 0.85. The results indicates that the present adaptive triangular grid method is accurate and useful for laminar viscous flow calculations.

• 대한조선학회논문집
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• 제34권2호
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• pp.85-89
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• 1997

주어진 곡면에 대한 Marking Data의 자동생성 알고리즘과 이에 의거한 전산 시스템의 개발은 강판의 곡가공 자동화 시스템 구축에 있어서 우선적으로 선행되어야 할 연구로서, 이 논문에서는 실제 곡면모델을 대상으로 기 개발한 전산시스템이 생성하는 Marking Data에 의거하여 실험을 수행함으로써 Marking Data의 자동생성을 위한 알고리즘과 개발된 전산시스템의 정당성을 확인하는 것에 중점을 주었다. 실제 곡면모텔에 대한 실험은 기 개발한 전산시스템의 결과 즉 Marking Data와 가열선에 대한 가열조건에 따라 현장에서 수행하였으며 그 결과를 Marking Data 생성 전산 시스템의 결과와의 비교를 통해 개발한 Marking Data 생성 전산 시스템의 현장에서 실용적 적용 가능성을 확인할 수 있었다. 끝으로 개발한 전산시스템의 보완과 확장에 대해 기술하였다.

• 대한조선학회논문집
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• 제48권2호
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• pp.178-182
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• 2011

Generally in order to reduce the steel weight of stiffened plate, stiffener spaces tend to be narrow and the plate gets thin. However, it will involve more fabrication cost because it can lead to the increase of welding length and the number of structural members. In the yard, the design which is able to reduce the total fabrication cost is needed, although it requires more steel weight. The purpose of this study is to find optimum stiffener spaces to minimize the fabrication cost for the cargo tank of LPG Carriers. Global optimization methods such as ES(Evolution Strategy) and GA(Genetic Algorithm) are introduced to find a global optimum solution and the sum of steel material cost and labor cost is selected as main objective function. Convergence degree of both methods in according to the size of searching population is examined and an efficient size is investigated. In order to verify the necessity of the optimum design based on the cost, minimum weight design and minimum cost design are carried out.