• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.13 no.4
• /
• pp.281-292
• /
• 2009

The solution of the interface problem or Poisson problem with concave corner has singular perturbation at the interface corners or singular corners. The decoupled dual singular function method (DDSFM) which exploits the singular representations of the solutions was suggested in [3, 9] and estimated optimal accuracy in [10]. The convergence rates consist with theoretical results even for the problems with very strong singularity, with the efficiency depending on parameters used in the methods. Furthermore the errors in $L^2$ and $L^\infty$-spaces display some oscillation, in the cases with meshsize not small enough. In this paper, we present an answer to remove the oscillation via numerical experiments. We observe the effects of parameters in DDSFM, and show the consisting efficiency of the method over the strong singularity.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.5
• /
• pp.81-88
• /
• 2002

An interface crack of a piezoelectric medium bonded between an elastic layer and a half-space is analyzed using the theory of linear piezoelectricity. Both out-of-plane mechanical and in-plane electrical loads are applied to the piezoelectric laminate. By the use of courier transforms, the mixed boundary value problem is reduced to a singular integral equation which is solved numerically to determine the stress intensity factors. Numerical analyses for various material combinations are performed and the results are discussed.

• 한국정보통신설비학회:학술대회논문집
• /
• 2009.08a
• /
• pp.141-142
• /
• 2009

Due to recent extreme weather, the information of the reliability for the nation's major social overhead capital (SOC) is emerging as a major issue. So the real-time monitoring of the underground state has become a very important. This paper is about a open USN platform for the underground information collection. Various sensors to collect information for the underground is used. The interface and the power of each sensor may vary. In order to solve the interface and power problem, this paper refer to the open interface, the network required for an open platform and the energy problem.

• Journal of the Society of Naval Architects of Korea
• /
• v.47 no.1
• /
• pp.1-10
• /
• 2010

In the present paper, a numerical method based on the constraint interpolation profile (CIP) method is applied for simulating two-dimensional violent sloshing problems. The free surface boundary value problem is considered as a multiphase problem which includes water and air. A stationary Cartesian grid system is adopted, and an interface capturing method is used to trace the shape of free surface profile. The CIP combined unified procedure (CCUP) scheme is applied for flow solver, and the tangent of hyperbola for interface capturing (THINC) scheme is used for interface capturing. Numerical simulations have been carried out for partially-filled 2D tanks under forced sway and roll motions at various filling depths and frequencies. The computational results are compared with experiments and/or the other numerical results to validate the present numerical method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.666-671
• /
• 2002

For a large structure, substructure based SDM(structural dynamics modification) method is very effective to raise its dynamic characteristics. Dividing into smaller substructures has a major advantage in the aspect of computation especially for getting sensitivities, which are in the core of SDM process. But quite often, non-matching nodes problem occurs in the process of synthesizing substructures. The reason is that, in general, each substructure is modelled separately, then later combined together to form a entire structure model under interface constraint conditions. Without solving the non-matching nodes problem, the substructure based SDM can not be processed. In this work, virtual node concept is introduced. Lagrange multipliers are used to enforce the interface compatibility constraint. The governing equation of whole structure is derived using hybrid variational principle. The eigenvalues of whole structure are calculated using determinant search method. The number of degrees of freedom of the eigenvalue problem can be drastically reduced to just the number of interface degree of freedom. Thus, the eigenvalue sensitivities can be easily calculated, and further SDM can be efficiently performed. Some numerical problems are tested to show the effectiveness of handling non-matching nodes.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.6
• /
• pp.1205-1215
• /
• 1992

The solidification rate is of special importance in determining the casting structures and properties. The heat transfer characteristics at the interface between the mold and the casting is one of the major factors that control the solidification rate. The thermal resistance exists due to the air-gap formation at the mold/casting interface during the freezing process. In this study two-dimensional Stefan problem with air-gap resistance in the rectangular mold is considered and the heat transfer characteristics is numerically examined by using the enthalpy method. The effects of the major parameters, such as mold geometry, thermal conductivity, heat transfer coefficient, and initial temperature of casting, on the thermal characteristics are investigated.

• Korean Journal of Mathematics
• /
• v.12 no.1
• /
• pp.91-106
• /
• 2004

We prove the regularity of a moving interface of the solutions of the initial value problem of equation (1.1) is $C^{\infty}$.

• Journal of Korean Institute of Industrial Engineers
• /
• v.38 no.3
• /
• pp.173-181
• /
• 2012

The size and layout of user interface components need to be optimally designed in terms of reachability, visibility, clearance, and compatibility in order for efficient and effective use of products. The present study develops an ergonomic design method which optimizes the size and layout of user interface components using adaptive genetic algorithm. The developed design method determines a near-optimal design which maximizes the aggregated score of 4 ergonomic design criteria (reachability, visibility, clearance, and compatibility). The adaptive genetic algorithm used in the present study finds a near-optimum by automatically adjusting the key parameter (probability of mutation) of traditional genetic algorithm according to the characteristic of current solutions. Since the adaptive mechanism partially helps to overcome the local optimality problem, the probability of finding the near-optimum has been substantially improved. To evaluate the effectiveness of the developed design method, the present study applied it to the user interface design for a portable wireless communication radio.

• Proceedings of the ESK Conference
• /
• 1998.04a
• /
• pp.93-98
• /
• 1998

Recently, consumers are tend to purchase the user-centered designed product using interface enginnering and human factors techniques. Therefore, it is important that the designer's requirements should be analyzed focused on the human machine interface. This paper described the interface usability evaluation technique(suvjective evaluation) for the interface between user and product. This methodology is the integrated interface usbility evaluation method AHP and Conjoint Analysis. AHP(Analytic Hierarchy Process) is a multicriteria decision model to give priority after expressing hierarchically for decision making problem. Conjoint Analysis enduavors to unravel the value, or partworths, that consumers place on the product or service's attributes from experimental subjects' evluation of profiles based on hypothetical products or services. A new usability test methodology proposed by this paper includes techniques jointed both consistency test by AHP and experimental subjective evaluation of profiles by Conjoint Analysis for evaluating the user's emotion and impression.

• Proceedings of the KSPS conference
• /
• 2002.11a
• /
• pp.111-114
• /
• 2002

Complementary use of several modalities in human-to-human communication ensures high accuracy, and only few communication problem occur. Therefore, multimodal interface is considered as the next generation interface between human and computer. This paper presents the current status and research themes of speech-based multimodal interface technology, It first introduces about the concept of multimodal interface. It surveys the recognition technologies of input modalities and synthesis technologies of output modalities. After that it surveys integration technology of modality. Finally, it presents research themes of speech-based multimodal interface technology.