• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.11-20
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• 1993

Sensitivity information is required in the optimal design process. In structural optimization, sensitivity calculation is a bottleneck due to its complexities and expensiveness. Various schemes have been proposed for the calculation. Analytic and finite difference methods are the most popular at the present time. However, they have advantages and disadvantages in different ways. Semi-anayltic method has been suggested to overcome the difficulties. In spite of the excellency, the semi-analytic method has been found to possess numerical error quite much with respect to shape variables. In this research, the error from each method is evaluated and compared using a shape variable. A two-dimensional beam is selected for an example since it has mathematical solution. An efficient method is suggested for the structural optimization which utilizes finite element method.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.4
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• pp.66-74
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• 2000

In this paper, hydroelastic responses of the very large floating structure are studied based on the linear potential theory. A theoretical method is developed to analyze the hydroelastic reponses of very large floating structures(VLFS) using the pressure distribution method and the modal expansion method. The singularities distributed on a zero draft plate at the free surfaces and hydrodynamic pressures are evaluated. The deflections of structure are expanded approximately in terms of natural mode functions of free-free beam. The calculated items are pressure distributions. vertical motions, hydrodynamic coefficients and bending moments of VLFS. The numerical results are compared with those measured by experiments.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.138-145
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• 2005

This paper describes a technique for detecting the boundary of the optic disk in digital image of the retina using inward and outward curve evolution. This paper offers medical information about glaucoma progresses. For accurate boundary detection, image inpainting based on texture synthesis removes blood vessels crossing the optic disk. For removing noises and preserving boundary of optic disk in image inpainting process, the anisotropic diffusion filtering is necessary. After pre-processing, the optic disk boundary is determined using inward and outward curve evolution. The experimental results show that the algorithm is effective for detection of optic disk boundary.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1137-1141
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• 2008

본 연구에서는 경기도 설마천 지역에 위치한 독립사면에서 토양수분을 연속측정한 결과를 분석하였다. 관측망의 설계를 통하여 선정한 위치에 탐침을 매설하고 공간적인 분포를 가진 시계열 형태의 데이터를 10cm 깊이에서 수집하였다. 전이함수 모형을 사면에서의 토양수분 전이과정에 대응하고, 이를 실제 측정한 데이터에 의해서 분석한 결과와 비교해 보았다. 전이 함수 모형은 강우 데이터를 입력변수로 하고 토양수분 시계열 데이터를 반응 변수로 하여 전개하였고, 시계열 모형의 전개는 크게 자료전처리, 모형구조의 규명, 모수추정, 모형진단 등의 과정을 통해서 적합한 모형을 도출하였다. 산지 사면에서의 토양수분을 전이함수에 의하여 전개한 모형은 토양수분의 깊이별 변화와 지형적 분포 양상에 따라 특색을 나타내었다. 또한 2003년 가을과 2004년 봄의 전이함수 모형 추정을 통하여 계절별 특성이 나타남을 알 수 있는데, 봄의 토양수분의 분포는 가을의 토양수분에 비하여 큰 변동성과 고차항의 반응양상을 보인다. 본 연구는 전이함수를 이용한 토양수분의 시계열 분석이 사면에서의 토양수분 변동특성을 지형적, 계절적 특성과 연계하여 이해하고 특성화하는 과정의 적절한 도구가 될 수 있음을 보여주고 있다.

• Nuclear Engineering and Technology
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• v.27 no.6
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• pp.870-876
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• 1995

In this paper, a new three-dimensional nodal diffusion code which is based on the AFEN methodology is described and tested. The method expands the homogeneous flux within a node in ter-ms of eighteen analytic basis functions satisfying the diffusion equation at any point of the node. And the nodal coupling equations are derived such that nodal balance, current continuity and leakage balance within an infinitesimally small box around the edge are satisfied. To verify its accuracy, the code was applied to the well-known static LMW benchmark problem and a small core benchmark problem that has the same material properties as the three-dimensional IAEA benchmark problem and compared with two other codes (QUANDRY, VENTURE). The results show that the code provides good accuracy both in the power distribution and in the effective multiplication factor.

• Management & Information Systems Review
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• v.32 no.1
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• pp.273-287
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• 2013

Increased over time are the market size of coffee shops and customer demands for coffee. This paper aims to provide solutions for quality improvement in products and services of coffee shops through a case study. SERVQUAL is adopted and modified for the given problem to identify customer requirements for services of coffee shops. Quality Function Deployment (QFD) is introduced as an effort to reflect customer requirements in engineering characteristics for products and services. This paper compares the market competitiveness of three coffee shops in a case study. This study also draws solutions for quality improvement in engineering characteristics for products and services by using QFD.

• Korean journal of applied entomology
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• v.41 no.1
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• pp.67-73
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• 2002

Studies were conducted to investigate the control effects of several insecticides on Apolygus(=Lygocoris) spinolae(Meyer-Dur) and to develop its management strategies in grapevine yards. Of insecticides which were applied by farmers in commercial grapevine yards, chlorpyrifos, parathion, fenvalerate, and esfenvalerate$.$fenitrothion showed good control effects against A. spinolae. In designed field experiments of fenitrothion and chlorpyrifos for the evaluation of A. spinolae control, both insecticides showed high control efficacy of 94.8 and 91.6%, respectively. The damage of A. spinolae was examined in a grapevine yard, where five different combinations of application timing and number were treated with fenitrothion to assess yield losses (average cluster weight) by A. spinolae. There were no significant differences among average cluster weights of sprayed vines; 466.0 g in sprayed vines on 2 to 3 leaves unfolded stage, 460.7g in sprayed vines on flower separating stage, 465.0 g in sprayed vines each on 2 to 3 leaves unfolded and flowers separating stage, and 487.4 g in sprayed vines each on 2 to 3 leaves unfolded, flowers separating and fruit set stage. Weights of fruit clusters of unsprayed vines was significantly lower than those of sprayed vines. Based on yield and spray cost, chemical control on 2 to 3 leaves unfolded stage produced higher net income than each spray on 2 to 3 leaves unfolded and flower separating stage (i.e., two times of spray), and produced similar net income as each spray on 2 to 3 leaves unfolded, flowers separating and fruit set stage (i.e., three times of spray). Thus, the 2 to 3 leaves unfolded stage was economical spray timing to controlA. spinolae in grapevine yards. Also, management strategies for A. spinolae were discussed.

• Composites Research
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• v.20 no.6
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• pp.15-20
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• 2007

In this work, the structural response of thin-walled, composite beams with built-in twist angles is analyzed using a mixed beam approach. The analytical model includes the effects of elastic couplings, shell wall thickness, and torsion warping. Reissner's semi-complimentary energy functional is used to describe the beam theory and also to deal with the mixed-nature in the beam kinematics. The bending and torsion related warpings introduced by the non-zero pretwist angles are derived in closed-form through the proposed beam formulation. The theory is validated with available literature and detailed finite element analysis results for rectangular solid section beams with elastic couplings. Very good correlation has been obtained for the cases considered.

• Journal of KSNVE
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• v.11 no.1
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• pp.111-117
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• 2001

Present work deals with a study on the deployment or retraction of cantilever beam that includes the rigid-body motion of large displacement of beam through the translational and rotational motions in 2-dimensional plane. The equations of motion are derived with respect to non-Cartesian coordinate system. In the formulation of equations of motion, shear deformations and geometrically non-linear effect are included. An assumed mode method is applied and numerical convergence characteristics are studied also. Types of motion of the moving beam are assumed to be classified as‘slow’or‘fast’motion, and the dynamic characteristics are investigated.

• Vending industry
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• v.2 no.4 s.5
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• pp.49-52
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• 2002

자판기가 꾸는 최고의 꿈은 무엇일까, 그것은 아마도 완전 무인화를 통해 유통의 모든 것을 대신하는 오토피아의 세계일 것이다. 자판기를 미래지향적 유통기기라 하는 것도, 또 산업계가 현재의 가능성보다는 내일을 더욱 중시하며 인고의 길을 마다하지 않는 이유도 분명 그 세계를 향한 꿈에 있을 게다. 이런 점에서 볼 때 최근 시장전개라 모색되는 오토 샵 시스템은 자판기의 미래지향적 꿈에 가장 근접한 기종이라 할 수 있다. 구성에 따라서는 수백가지 아이템을 인력 없이 판매할 수 있는 이 무인 시스템은 오토피아 세계를 향한 가능성의 시험대로서도 기대가 크다. 무인화에 있어서는 결코 한번 간 길은 되돌아가지 않는다. 일단 무인화가 되기가 힘들어서 그렇지 일정 단계에 도달하면 다시 유인으로 되돌아가기에는 너무 익숙하고 편해져 있게 마련이다. 오토 샵 시스템 역시 이 같은 흐름을 제대로 탈 수 있다면 오토피아의 대표주자로서 빠른 파급력을 기대해 볼 수 있다. 하지만 결코 쉽지 않은 길. 누구도 가지 않았기에 험난하고 힘들 수밖에 없는 그 길 위에서 오토피아 꿈들을 아직은 가능성 하나만을 믿고 매달려야 하는 시점이다. 금호 현장진단에서는 키오스텍에서 전개하는 '솔드아웃'을 통해 오토샵 시장의 가능성을 진단해 보는 시간을 마련했다.