• Structural Engineering and Mechanics
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• 제76권2호
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• pp.239-250
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• 2020

This paper deals with free vibration of plates with steps and internal line supports by using a modified matched interface and boundary (MMIB) method. Different kinds of interfaces caused by steps, rigid and elastic line supports and their combinations are taken into account. Detailed MMIB procedures for dealing with these different interfaces are presented. Various examples are chosen to illustrate the accuracy and convergence of MMIB method. Numerical results show that the proposed MMIB is a highly accurate and convergent approach for solving the title issue. This study will extend the application range of MMIB method.

• 대한수학회보
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• 제51권3호
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• pp.717-737
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• 2014

We study the effect of numerical quadrature in space on semidiscrete and fully discrete piecewise linear finite element methods for parabolic interface problems. Optimal $L^2(L^2)$ and $L^2(H^1)$ error estimates are shown to hold for semidiscrete problem under suitable regularity of the true solution in whole domain. Further, fully discrete scheme based on backward Euler method has also analyzed and optimal $L^2(L^2)$ norm error estimate is established. The error estimates are obtained for fitted finite element discretization based on straight interface triangles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4451-4466
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• 2014

We present joint radio selection and relay scheme that delivers data from a source to a sink in heterogeneous stationary sensor networks consisting of various radio interfaces. The proposed scheme finds the optimal relay nodes and their corresponding radio interfaces that minimize energy consumption throughout the network while satisfying the end-to-end packet deadline requirement. We formulate the problem of routing through radio interface selection into binary integer programs, and obtain the optimal solution by solving with an optimization solver. We examine a trade-off relationship between energy consumption and packet delay based on network level simulations. We show that given the end-to-end deadline requirement, our routing algorithm finds the most energy-efficient routing path and radio interface across mesh hops. We demonstrate that the proposed routing scheme exploits the given packet delivery time to turn into network benefit of reducing energy consumption compared to routing based on single radio interface.

• 한국자동차공학회논문집
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• 제5권6호
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• pp.141-147
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• 1997

For the effective finite element analysis of the structures including material interfaces or contact surfaces, interface elements are proposed. Most of early works in this problem require not only iterative computation but also complex formulation because of the kinematic nonlinearities caused from the discontinuous behavior and the stress concentration phenomena. The proposed elements, however, are consistently formulated using relative displacements and tractions between top and bottom regular finite elements. The effectiveness of these elements are shown by solving various numerical sample problems including an leaf spring and comparing with results of general finite element analysis. As a result, more stable solutions are conveniently obtaines using interface elements than regular finite elements.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.19-24
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• 1997

In this study, we extend the application of the interface-matrix(IM) method for reflector modeling to Analytic Flux Expansion Nodal (AFEN) method. This include the modifications of the surface-averaged net current continuity and the net leakage balance conditions for IM method in accordance with AFEN fomular. AFEN-interface matrix (AFEN-IM) method has been tested against ZION-1 benchmark problem. The numerical result AFEN-IM method shows 1.24% of maximum error and 0.42% of root-mean square error in assembly power distribution, and 0.006%Δk of neutron multiplication factor. This result proves that the interface-matrix method for reflector modeling can be useful in AFEN method.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권4호
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• pp.213-219
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• 2000

In this paper, a controller design method is proposed for haptic interface considering transparency and robust stability. For this, a performance index for the transparency as performance measure is defined in the points of impedance matching and the optimal solution which is minimizing the performance index is obtained by solving H2 optimal problem. In haptic interface, the modeling uncertainties can be restricted to that of haptic device. To implement the robust stabilizing haptic controller to the uncertainties of haptic device, a robust stable condition using H$\infty$ norm from small gain theorem is proposed. To verify the effectiveness of the proposed haptic controller design scheme, numerical examples and experimental results are illustrated for virtual wall consisting of stiffness and damping factor.

• 한국공작기계학회논문집
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• 제11권6호
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• pp.91-97
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• 2002

Applications of brazing in the studying fields such as high-speed machining are very increasing in various industry fields. Therefore, applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem dissimilar materials in brazed interface. In this study, stress intensity factor(SIF) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a hardmetal and a HSS by two dimensional(2-D) BEM. Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine SIF.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.90-92
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• 2022

본 논문에서는 국내에 다양한 분야에 도입되어 있는 키오스크의 접근성 향상을 위한 인터페이스 개선 설계를 제안한다. 키오스크는 터치식 스크린을 활용한 무인 시스템으로 특히 외식분야에 특화 되어 있다. 하지만 키오스크의 직관성이 부족함에 따라서 키오스크의 사용을 포기하는 사람이 늘어나고 있다. 이를 해결하기 위해서 인터페이스 단계에서 직관성 및 사용학습성을 높여 기존의 키오스크의 사용을 기피하는 사람들의 편의성을 증대시키며, 이를 통하여 키오스크의 접근성을 높이는 것을 목적으로 한다.

• Management Science and Financial Engineering
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• 제10권2호
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• pp.89-102
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• 2004

In this paper, we deal with a processor assignment problem that minimizes the total traffic load of an ATM switch controller by optimally assigning processors to ATM interface units. We develop an integer programming (IP) model for the problem, and devise an effective tabu search heuristic. Computational results reveal the efficacy of the proposed tabu search procedure, finding a good quality solution within 5% of optimality gap.

• Structural Engineering and Mechanics
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• 제62권1호
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• pp.113-123
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• 2017

The bi-material elastic system consisting of the circular hollow cylinder and the infinite elastic medium surrounding this cylinder is considered and it is assumed that on the inner free face of the cylinder a point-located axisymmetric time harmonic force, with respect to the cylinder's axis and which is uniformly distributed in the circumferential direction, acts. The shear-spring type imperfect contact conditions on the interface between the constituents are satisfied. The mathematical formulation of the problem is made within the scope of the exact equations of linear elastodynamics. The focus is on the frequency-response of the interface normal and shear stresses and the influence of the problem parameters, such as the ratio of modulus of elasticity, the ratio of the cylinder thickness to the cylinder radius, and the shear-spring type parameter which characterizes the degree of the contact imperfectness, on these responses. Corresponding numerical results are presented and discussed. In particular, it is established that the character of the influence of the contact imperfection on the frequency response of the interface stresses depends on the values of the vibration frequency of the external forces.