• Structural Engineering and Mechanics
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• 제85권3호
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• pp.419-432
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• 2023

This paper studies the effects of porosity distributions on buckling and post-buckling behaviors of a functionally graded saturated porous (FGSP) circular plate. The plate is under the uniformly distributed radial loading and simply supported and clamped boundary conditions. Pores are saturated with compressible fluid (e.g., gases) that cannot escape from the porous solid. Elastic modulus is assumed to vary continuously through the thickness according to three different functions corresponding to three different cases of porosity distributions, including monotonous, symmetric, and asymmetric cases. Governing equations are derived utilizing the classical plate theory and Sanders nonlinear strain-displacement relations, and they are solved numerically via shooting method. Results are verified with the known results in the literature. The obtained results for the monotonous and symmetric cases with the asymmetric case presented in the literature are shown in comparative figures. Effects of the poroelastic material parameters, boundary conditions, and thickness change on the post-buckling behavior of the plate are discussed in details. The results reveal that buckling and post-buckling behaviors of the plate in the monotonous and symmetric cases differ from the asymmetric case, especially in small deflections, that asymmetric distribution of elastic moduli can be the cause.

• 한국산학기술학회논문지
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• 제13권3호
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• pp.1325-1329
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• 2012

본 논문은 실내 사격 전용 총기의 개발, 고속의 레이저 인식 알고리즘 개발을 통하여 다양한 그래픽 컨텐츠와 연동할 수 있는 실내용 스크린 사격 시스템을 제안한다. 내구성이 강하며 공압 솔래노이드 밸브 제어와 비가시 레이저를 전용 총기에 적용하였으며, 비가시 레이저를 고속으로 인식하여 그래픽 엔진와 상호작용하는 방법을 개발하여 실내용 스크린 사격 시스템을 상용화 하고자 한다.

• Coupled systems mechanics
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• 제1권2호
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• pp.155-163
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• 2012

This paper presents analytical approximate solutions for the initial post-buckling deformation of the pipes in oil and gas wells. The governing differential equation with sinusoidal nonlinearity can be reduced to form a third-order-polynomial nonlinear equation, by coupling of the well-known Maclaurin series expansion and orthogonal Chebyshev polynomials. Analytical approximations to the resulting boundary condition problem are established by combining the Newton's method with the method of harmonic balance. The linearization is performed prior to proceeding with harmonic balancing thus resulting in a set of linear algebraic equations instead of one of non-linear algebraic equations, unlike the classical method of harmonic balance. We are hence able to establish analytical approximate solutions. The approximate formulae for load along axis, and periodic solution are established for derivative of the helix angle at the end of the pipe. Illustrative examples are selected and compared to "reference" solution obtained by the shooting method to substantiate the accuracy and correctness of the approximate analytical approach.

• Journal of Information Processing Systems
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• 제15권4호
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• pp.785-796
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• 2019

Due to the view point, illumination, personal gait and other background situation, person re-identification across cameras has been a challenging task in video surveillance area. In order to address the problem, a novel method called Joint Bayesian across different cameras for person re-identification (JBR) is proposed. Motivated by the superior measurement ability of Joint Bayesian, a set of Joint Bayesian matrices is obtained by learning with different camera pairs. With the global Joint Bayesian matrix, the proposed method combines the characteristics of multi-camera shooting and person re-identification. Then this method can improve the calculation precision of the similarity between two individuals by learning the transition between two cameras. For investigating the proposed method, it is implemented on two compare large-scale re-ID datasets, the Market-1501 and DukeMTMC-reID. The RANK-1 accuracy significantly increases about 3% and 4%, and the maximum a posterior (MAP) improves about 1% and 4%, respectively.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2021년도 제64차 하계학술대회논문집 29권2호
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• pp.469-470
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• 2021

본 논문에서 제안하는 슈팅게임 제자작 방법은 게임엔진으로 언리얼 엔진 4(Unreal Engine 4)를 사용하고 있다. 기존의 언리얼 엔진 기반의 게임은 총알에 데미지 판정 기법을 사용하지만, 슈팅게임 제작에서 중요한 요소인 정확성을 높이기 위해서 Line Trace 기술을 활용하는 기법을 제안한다.

• 한국전기전자재료학회논문지
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• 제18권9호
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• pp.781-786
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• 2005

The binding energy in the n-type $GaAs/Al_xGa_{1-x}As$ quantum well is calculated. The shooting method, modified from the finite difference method, is used for the calculation of the subband energy level and its wave function. In order to account tot the change of the potential energy due to the charged particles, impurities and electrons, the self consistent method is employed. The wave function used for the calculation of the binding energy is assumed to be composed of the envelope function and hydrogenic 1s function. Then, the binding energies calculated by taking into account lot two different types of the hydrogenic 1s function are compared.

• Computers and Concrete
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• 제30권2호
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• pp.143-150
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• 2022

In this paper, the non-linear mathematical problem is solved via numerical scheme by utilizing shooting method. Brownian diffusion and thermophoresis along mass and heat transfer are accounted for. Non-linear expression is reduced via non-dimensional variables. The simplified ordinary differential equations are tackled by shooting technique. Behavior of distinct influential parameters is investigated graphically and analyzed for temperature and concentration profile. Our finding indicates that temperature profile is enhanced for the thermophoresis, Brownian motion coefficient, Prandtl number, Eckert number and temperature slip parameter. Comparison of numerical technique with the extant literature is made and an acceptable agreement is attained. Graphs are plotted to examine the influence of these parameters.

• International Journal of Aeronautical and Space Sciences
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• 제11권1호
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• pp.10-18
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• 2010

The purpose of this paper deals with direct multiple-shooting method (DMS) to resolve helicopter maneuver problems of helicopters. The maneuver problem is transformed into nonlinear problems and solved DMS technique. The DMS method is easy in handling constraints and it has large convergence radius compared to other strategies. When parameterized with piecewise constant controls, the problems become most effectively tractable because the search direction is easily estimated by solving the structured Karush-Kuhn-Tucker (KKT) system. However, generally the computation of function, gradients and Hessian matrices has considerably time-consuming for complex system such as helicopter. This study focused on the approximation of the KKT system using the matrix exponential and its integrals. The propose method is validated by solving optimal control problems for the linear system where the KKT system is exactly expressed with the matrix exponential and its integrals. The trajectory tracking problem of various maneuvers like bob up, sidestep near hovering flight speed and hurdle hop, slalom, transient turn, acceleration and deceleration are analyzed to investigate the effects of algorithmic details. The results show the matrix exponential approach to compute gradients and the Hessian matrix is most efficient among the implemented methods when combined with the mixed time integration method for the system dynamics. The analyses with the proposed method show good convergence and capability of tracking the prescribed trajectory. Therefore, it can be used to solve critical areas of helicopter flight dynamic problems.

• Asian-Australasian Journal of Animal Sciences
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• 제12권1호
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• pp.9-14
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• 1999

Factors affecting gene gun-mediated expression of the human erythropoietin gene were investigated in primary cultured oviduct cells from laying hens. The human erythropoietin gene was transfected by a gene gun method at $1.25{\mu}g$ per dish, and cultured in a synthetic serum-free medium for 72 hrs. The concentration of human erythropoietin mRNA was determined by RNA : RNA solution hybridization. In experiment 1, the effect of changing the shooting pressure of DNA-coated microparticles with nitrogen gas was tested at 20 and $60kgf/cm^2$. The results showed that the erythropoietin mRNA concentration was significantly higher at 60 than $20kgf/cm^2$. In experiment 2, the effects of supplementing the medium with fetal calf serum at 10%, and raising the shooting pressure from 60 to $80kgf/cm^2$ on the cell number and erythropoietin gene expression were examined. Although supplementation with fetal calf serum significantly increased the cell numbes compared with no supplemented controls (p < 0.05), erythropoietin mRNA concentration per $10^3$ cells was not affected. Raising the shooting pressure from 60 to $80kgf/cm^2$ did not affect either of the parameters, In experiment 3, the effect of supplementing ascorbate 2-phosphate at 0.5 mM was tested. The results indicated that the ascorbate supplementation significantly increased the cell number (p < 0.05), and tended to increase erythropoietin mRNA concentration (p < 0.1). Thus, for human erythropoietin gene expression by using the gene gun method, shooting pressure with nitrogen gas should be sufficient at $60kgf/cm^2$ and supplementation with ascorbate phosphate would be useful to enhance not only the cell proliferation but also erythropoietin gene expression.

• 한국컴퓨터정보학회논문지
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• 제27권8호
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• pp.85-90
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• 2022

본 연구는 실제 카메라의 움직임과 동일한 가상 카메라의 움직임을 구현하기 위해 전통적인 모션그래픽 제작 방법이 가지고 있는 소요시간과 비용에 대한 단점을 줄이기 위해 AR Core 기반의 모바일 디바이스 실시간 트래킹 데이터를 이용하여 모션그래픽 가상카메라를 생성하는 방법을 제안했다. 제안하는 방법은 촬영 이후 저장된 비디오 파일에서의 트래킹 작업을 간소화하고, 촬영 단계에서 트래킹 성공 유무를 판단하기 위해 AR Core 기반 모바일 디바이스에서 촬영과 동시에 진행하는 방법이다. 실험결과 전통적인 방법과 비교하였을 때 모션그래픽 결과 이미지의 차이는 없었으나 300프레임(frame) 영상 기준 6분 10초의 시간이 소모된 반면에 제안한 방법은 이 단계를 생략할 수 있어 매우 높은 시간적 효율성을 갖는다. 현재 가상 증강 현실을 이용한 영상제작에 대한 관심과 다양한 연구가 진행되고 있는 시점에서 본 연구는 가상 카메라 생성과 매치 무빙 등에서 활용될 있을 것이다.