• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.101-103
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• 1999

This paper presents an analysis of 2-dimensional(2-D) multi-regions problem using boundary integral equation method(BIEM). When compared with finite element method(FEM), there are only a few unknown variables in BIEM because it implements numerical analysis only for the surface or boundary of a model. As a result, a lot of computational memory and time can be saved. Procedure to analyze 2-D multi-regions problem using potentials and its derivatives in a boundary as unknown variables, first, numerical analysis is performed for each of subregions. And then interface continuity condition is applied to the interface between them and Gauss Quadrature Formula are adopted to solve singular integral in a boundary in this paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.891-897
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• 1999

The heat transfer characteristics at the interface between the mold and the casting is one of the major factors for the solidification speed which determines the casting structures. The thermal resistance exists due to air gap formation at the mold/casting interface during the freezing process. In this study one dimensional Stefan problem with the air-gap resistance in the cylindrical mold is considered and the heat transfer characteristics is numerically examined by using the enthalpy method which is convenient in solving the Stefan problem with mushy zone. The present results agreed very well with those of previous papers. The effects of major parameters such as thermal conductivity, heat transfer coefficient of mold, on the thermal characteristics are investigated.

• Journal of the Ergonomics Society of Korea
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• v.18 no.3
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• pp.55-72
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• 1999

Evaluation of user interfaces has to be performed in an intuitive and subjective manner by experts especially when the problem comes to the complexity and consistency of sophisticated interface procedures. The manual analysis and evaluation of logical interfaces also tends to be slow and laborious. To make the evaluation more formal and objective, the criteria and the procedure with which the evaluation can proceed must be explicitly prescribed. Furthermore, to make the formal procedure as practical as subjective expert evaluation, the criteria must reflect the user knowledge of the target tasks since the task knowledge plays the role of a basis for users to understand the interface organizations and procedures. This paper describes ESTIM, a support system for task-based evaluation of user interface, that includes the interface evaluation criteria and implies an evaluation procedure. The support system can be used either in an interactive manner by the analyst during the evaluation or in an automatic evaluation mode. It was verified that the result of automatic evaluation by ESTIM matched the results of expert evaluation fairly well.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.6
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• pp.771-775
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• 2004

The present Web surroundings is mostly composed of HTML(Hypertext Mark-up Language) and thereby users obtain web informations mainly in GUI(Graphical User Interface) environment by clicking mouse in order to keep up with hyperlinked informations. However it is very inconvenient to work in this environment comparing with easily accessed one in which human`s voice is utilized for obtaining informations. Using VoiceXML, resulted from XML, for supplying the information through telephone on the basis of the contemporary matured technology of voice recognition/synthesis to work out the inconvenience problem, this paper presents the research results about VoiceXML VUI(Voice User Interface) Browser designed and implemented for realizing its technology and also the VoiceXML Dialog designed for the purpose of the browser's efficient use.

• Journal of the Korean Mathematical Society
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• v.50 no.6
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• pp.1291-1310
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• 2013

This paper develops least-squares pseudo-spectral collocation methods for elliptic boundary value problems having interface conditions given by discontinuous coefficients and singular source term. From the discontinuities of coefficients and singular source term, we derive the interface conditions and then we impose such interface conditions to solution spaces. We define two types of discrete least-squares functionals summing discontinuous spectral norms of the residual equations over two sub-domains. In this paper, we show that the homogeneous least-squares functionals are equivalent to appropriate product norms and the proposed methods have the spectral convergence. Finally, we present some numerical results to provide evidences for analysis and spectral convergence of the proposed methods.

• Structural Engineering and Mechanics
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• v.38 no.5
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• pp.573-592
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• 2011

Comprehensive and accurate analysis of a finite foundation beam is a challenging engineering problem and an important subject in foundation design. One of the limitation of the traditional Winkler elastic foundation model is that the model neglects the effect of the interface resistance between the beam and the underneath foundation soil. By taking the beam-soil interface resistance into account, a deformation governing differential equation for a finite beam resting on the Winkler elastic foundation is developed. The coupling effect between vertical and horizontal displacements is also considered in the presented method. Using Galerkin method, semi-analytical solutions for vertical and horizontal displacements, axial force, shear force and bending moment of the beam under symmetric loads are presented. The influences of the interface resistance on the behavior of foundation beam are also investigated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.459-464
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• 2010

The dynamic propagation of an interface crack between two dissimilar functionally graded layers under anti-plane shear is analyzed using the integral transform method. The properties of the functionally graded layers vary continuously along the thickness. A constant velocity Yoffe-type moving crack is considered. Fourier transform is used to reduce the problem to a dual integral equation, which is then expressed to a Fredholm integral equation of the second kind. Numerical values on the dynamic energy release rate (DERR) are presented. Followings are helpful to increase of the resistance of the interface crack propagation of FGM: a) increase of the gradient of material properties; b) increase of the material properties from the interface to the upper and lower free surface; c) increase of the thickness of FGM layer. The DERR increases or decreases with increase of the crack moving velocity.

• Multiscale and Multiphysics Mechanics
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• v.1 no.1
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• pp.35-51
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• 2016

In this paper, a mixed-mode cohesive law for an interface crack between epoxy and TR (transparent thermoplastic) resin is inversely estimated by the field projection method using numerical solutions and experimentally measured displacements. Displacements in a region far away from the crack tip are measured by digital image correlation technique. An inverse analysis, the field projection method formulated from the interaction J- and M-integrals with numerical auxiliary fields, is carried out to estimate a mixed-mode cohesive law for an interface crack between dissimilar materials. In the present approach, nonlinear deformations and damage near the crack tip are converted into the relationships of tractions and separations on crack surfaces behind the crack tip. The phase angle of mixed-mode singularities of the interface crack is also obtained from measured displacements in this study.

• Journal of Korea Multimedia Society
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• v.18 no.9
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• pp.1131-1139
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• 2015

The purpose of this research is creating the visualization platform of the user interface to make able to be provide the demanded service while users communication with surrounding space in a smart city environment. This comes from the latest enhanced interface technology and social media, and it uses the shares information to support the proper interface environment according to a life style and spatial properties. "EzCity" which is the user interface platform suggested in this research, can control the enormous amount of public data for the smart city. The core module of user platform is made up with Public data module, Interface module, Visualization module and Service module. The role of this platform is to be provide "Geo-Intelligent Interface Service" for space users to access the data in easier and more practical interface environment. This reinforces the visualization process for data collecting, systematization, visualization and providing service. Also this will be expected to be the base to solve the problem which complexity and rapidly increasing amount of data.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.159-166
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• 1998

The problem of interface crack in the bonded structures has received a great deal of attention in recent years. In this paper the aluminum bonded single lap-joint containing the interface edge crack is investigated. The tensile load and the average shear stress of the adhesive joints which have different crack length are obtained from the static tensile tests. The critical value of crack length to provoke the interface fracture is determined to a/L=0.4, where a is the interface crack length and L is the adhesive lap-length. The fracture mechanical parameters are introduced to confirm the existence of the critical crack length. The compliance and the stress intensity factors are calculated using the displacement and the stress near the interface crack tip by the boundary element method. These numerical results support the experimental results that the critical value of a/L is 0.4. It is known that the compliance and the stress intensity factors are the efficient parameters to estimate the bonded single lap-joint containing the interface edge crack.