• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.194-197
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• 1995

In this study, we performed a modeling for $K^{+}$ ion-exchanged diffused channel waveguide and waveguide-type optical coupler by WKB(Wentzel-Kramer-Brillouim) dispersion equation, field distribution equation of mode and coupled mode theory, and examined the optical-power-dividing of the optical coupler fabricated by using the modeling condition. The optical-power-dividing was observed at the waveguide-type optical coupler with 3[$\mu\textrm{m}$] line-width, 6[$\mu\textrm{m}$] space between channel waveguides, and 3[mm] interaction length.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.111-120
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• 2004

This paper presents an application of Unified Modeling Language(UML) software technique for developing transmission pricing evaluation package. Also, this paper describes a transmission pricing algorithm applicable to a large-scale power system. The usage-based transmission pricing mechanism is very complex since it requires power flow analysis, fault current analysis, sensitivity evaluation of a transmission line, penalty factors calculation, transmission asset databases, and cost allocation rules, etc. For the efficient and flexible development of the transmission pricing package, a UML. approach is applied, which is composed of a use-case diagram, interaction diagram, class diagram, and package diagram using Rational Rose Unified Process(RUP). The designed transmission pricing package can be efficiently modified and reused as the market environments evolves since it is designed by Object-Oriented Programming(OOP).

• Annual Conference on Human and Language Technology
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• 1996.10a
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• pp.75-84
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• 1996

인간의 가장 자연스러운 통신 수단은 자연언어이다. 본 논문에서는 자연언어 대화체를 사용한 인터네트 상에서의 정보 검색에 있어서 사용자 모델링 에이젼트 (User modeling Agent or User modeling system)의 모델 형성 기술 및 그의 역할을 서술하고 있다. 사용자 모델은 인간의 심성 모델 (Mental model)에 해당하며, 심성 모델이 사용자가 시스템에 대한 지식과 자신의 문제상황 또는 주변환경에 대하여 가지는 모델임에 반하여, 사용자 모델은 시스템이 사용자의 지식 및 문제 상황을 표상(Representation)하여 형성한 사용자에 대한 모델이다. 따라서 사용자 모델은 시스템의 지능적인 Human Computer Interaction (HCI)의 지원을 위하여 필수적이다. 본 논문에서는 사용자 모델 형성 기술 및 지능형 대화 모델의 지원을 위한 시스템 실례로써 사용자 모델 형성 시스템 $BGP-MS^2$ 와 사용자 모델의 형성을 위하여 구축된 지식베이스 구조를 설명하고 있다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.241-248
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• 1997

The super-structure in a soil-structure interaction analysis is commonly idealized as lumped parameter system. In this study, the complex shear wall structure is modeled using three different kinds of modeling techniques : 1) full FEM comparatively as an exact solution, 2)equivalent shear spring model assuming mainly shear deformations of the wall, 3) equivalent beam-stick model made by independent static analysis. Dynamic characteristics due to three different modeling methods are compared and investigated before performing structural response analysis. The beam-stick model in comparison to shear spring model gives closer dynamic responses when compared with the full FEM, even though it requires additional unit load static analyses.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.2
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• pp.96-103
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• 2010

A concept of preliminary design for mid-size superyachts is explored. First, the profile of a superyacht is interactively designed with the help of freeform curve functionality and graphical user interface (GUI) based interaction. The hull form is then constructed using major characteristic curves such as design waterline, deck sideline, and sections in addition to the predefined profile curve. After exterior hull modeling is done, the arrangement of significant interior spaces of all decks is carried out. A genetic algorithm is exploited to find a space arrangement by considering space fitness values, space proximity, and stairs connectivity of relevant spaces. A goal of the paper is to offer a step-by-step procedure for superyacht design from scratch or when initial information is not sufficient for complete design. For this purpose, a GUI based superyacht design system is developed. This design approach is expected to help users interactively design mid-size superyachts.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.25-36
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• 1994

The sheet metal forming process is one of the most important manufacturing processes in the modern industry. From the view point of mechanics involved, it is very difficult to predict whether a newly designed sheet metal part can be formed without defects such as fracture, wrinkling and surface unevenness, etc. In order to reduce the effort taken in the trial-and-error process and to control the process effectively, a systematic method for process modeling is to required. The aim of sheet forming simulation through the process modeling is to reduce the lead time for die disign and manufacture by process modeling is to reduce the lead time for die design and manufacture by means of investigating the deformation mechanics and the mutual interaction between the process parameters. In this paper, the necessity, the present status, and the future technology about CAE of sheet forming simulation have been discussed.

• Journal of Korean Association for Spatial Structures
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• v.17 no.3
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• pp.65-73
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• 2017

Recently, the trend is emerging a variety of irregular tall buildings. It is important to design the building for lateral load according to this trend. Fluid Structure Interaction(FSI) simulation can be performed to understand the vibrations of the structure against dynamic wind loads. In order to make the physical characteristics of the actual structure and the analytical model the same, we studied core inserting equivalent stiffness modeling method. As a result of this analysis, the stiffness of the structure can be set similar to that of the two axes of the structure, and turbulence can be reproduced through the acceleration tendency.

• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.71-87
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• 2012

This paper extends a single equation, semi-analytical approach for three-span bridges to multi-span ones for the rapid and precise determination of natural frequencies and natural mode shapes of an orthotropic, multi-span plate. This method can be used to study the dynamic interaction between bridges and vehicles. It is based on the modal superposition method taking into account intermodal coupling to determine natural frequencies and mode shapes of a bridge deck. In this paper, a four- and a five-span orthotropic roadway bridge deck are compared in the first 10 modes with a finite element method analysis using ANSYS software. This simplified implementation matches numerical modeling within 2% in all cases. This paper verifies that applicability of a single formula approach as a simpler alternative to finite element modeling.

• Structural Engineering and Mechanics
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• v.51 no.5
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• pp.809-821
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• 2014

The truss based steel bridge structures usually consists of gusset plates which lose their load carrying capacity and rigidity under the effect of repeated and dynamics loads. This paper is focused on modeling the nonlinear material behavior of the gusset plates of the Truss Based Bridges subjected to dynamics loads. The nonlinear behavior of material is characterized by a damage coupled elsto-plastic material models. A truss bridge finite element model is established in Abaqus with the details of the gusset plates and their connections. The nonlinear finite element analyses are performed to calculate stress and strain states in the gusset plates under different loading conditions. The study indicates that damage initiation occurred in the plastic deformation localized region of the gusset plates where all, diagonal, horizontal and vertical, truss member met and are critical for shear type of failure due tension and compression interaction. These findings are agreed with the analytical and experimental results obtained for the stress distribution of this kind gusset plate.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.23-24
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• 2015

In this talk, we will present what we believe is the state-of-the-art of the numerical modeling and simulation of the combustion processes as they relate to typical scramjet engines. The free-stream Mach number is hypersonic, but the speed is not sufficiently decelerated at the inlet/isolator, as in ramjets, so that combustion takes place under supersonic conditions. This creates some difficulties for most turbulence-combustion models. We delve into the details of these problems, by discussing the software programs that have a long track record for scramjet combustion simulation; with a focus on the accuracy of the baseline numerical methods used, the turbulence modeling/simulation approach, the comparative fidelity of the turbulence-combustion interaction models, ability to simulate premixed/non-premixed/partially-premixed, quenching/re-ignition capabilities, the numerical spark-plug method, Damkholer number regimes supported, and the effects of variable Prandtl, Schmidt, and Lewis numbers. Validation results from high-speed and low-speed combustion applications will also be presented.