• Transactions of Materials Processing
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• v.7 no.1
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• pp.66-71
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• 1998

The present study is concerned with the hydrostatic extrusion process of copper-clad aluminium bar to investigate the bonding conditions as well as the basic flow characteristics. Considering the bonding mechanism of bi-metal contact surface as cold pressure welding the normal pressure and the contact surface expansion are selected as process parameters governing the bonding conditions, in this study the critical normal pressure required for the local extrusion-the protrusion of virgin surfaces by the surface expansion at the interface-is obtained using a slip line method and is then used as a criteron for the bonding. A rigid plastic finite element method is used to analyze the steady state extrusion process. The interface profile of bi-metal rod is predicted by tracking the paths of two particles adja-process. The interface profile of bi-metal rod is predicted by tracking the paths of two particles adja-cent to interface surface. The contact surface area ration and the normal pressure along the interface are calculated and compared to the critical normal pressure to check bonding. It is found that the model predictions are generally in good agreement with the experimental observations. The compar-isons of the extrusion pressure and interface profile by the finite element with those by experi-ments are also given.

• Journal of the Korean Geotechnical Society
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• v.16 no.3
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• pp.89-89
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• 2000

The shear behavior of any interface is a function of the fundamental properties of both materials at the interface. This study aimed at investigating the effect of planar surface roughness on the stress-horizontal displacement curve at theinterfaces composed of various geomembrane textures and granular materials. In addition, the extent of surfacialscarring on smooth geomembranes against granular materials during shearing induced by plowing effect was studied. It wasobserved that the displacements required to achieve peak and residual interface resistance, and the stress-displacementcurve at the interface vary greatly with the surface roughness of geomembrane. Quantification of surface roughnessvariations on smooth geomembrane due to plowing effect showed that the surfacial scarring during shearing by the soilparticles is directly related to both the normal stress and the angularity of the soil particles at the interface. The findingsof this study can be used to provide the useful information for the design and selection of counterface materials.

• Nuclear Engineering and Technology
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• v.33 no.2
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• pp.241-253
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• 2001

Under severe accidents, the pressure and temperature response has an important role for the integrity of a nuclear power plant containment. The history of the pressure and temperature is characterized by the amount and state of steam/air mixture in a containment. Recently, the heat transfer rate to the structure surface is supposed to be increased by the wavy interface formed on condensate film. However, in the calculation by using CONTAIN code, the condensation heat transfer on a containment wall is calculated by assuming the smooth interface and has a tendency to be underestimated for safety. In order to obtain the best- estimate heat transfer calculation, we investigated the condensation heat transfer model in CONTAIN 1.2 code and adopted the new forced convection correlation which is considering wavy interface. By using the film tracking model in CONTAIN 1.2 code, the condensate film is treated to consider the effect of wavy interface. And also, it was carried out to investigate the effect of the different cell modelings - 5-cell and 10-cell modeling - for KNGR(Korean Next Generation Reactor) containment phenomena during a severe accident. The effect of wavy interface on condensate film appears to cause the decrease of peak temperature and pressure response . In order to obtain more adequate results, the proper cell modeling was required to consider the proper flow of steam/air mixture.

• Journal of the Ergonomics Society of Korea
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• v.27 no.1
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• pp.29-35
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• 2008

An estimated 1 billion mobile phone were sold globally in the year 2006. In Korea, people watch television 3.17 hours in a day. Television isn't what it used to be. Digital TV provides both interactivity and high definition. Mobile phone also transferred from 2G to 3G or 3.5G. This means the complexity of TV and mobile phone is increased, design of user interface is more difficult. Unlike the personal computer industry, TV and mobile phone industries have no standard user interface. A comparative study for user interface between TV and mobile phone is studied. User, task, system are analyzed in requirement analysis. User interface model and interaction are also analyzed between TV and mobile phone. This study provides some insights for user interface design. First, the UI designer have to consider another products because one user using one product at the same time using another products. Experience for one product affects that for another product. Second, TV and mobile phone show very similar pattern, especially interaction task and input interaction. Third, there are not sometimes optimized experience between service operator and device manufacturer. Cooperative design between them is required.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.975-980
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• 1993

In accordance with increase, if electronic power demanded, more efficient supervisory control of distribution system will be required. This study contains development of MMI(man-machine-interface) system with GUI(graphic-user-interface), for the automatic power distribution system. The main function of MMI system is to edit network of power distribution and to management of data base for network. The GUI function of MMI system enables more efficient management of power distribution system.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.8
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• pp.342-347
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• 2003

The suspension insulators are subjected to harsh environment in service for a long time. Long term reliability of the insulators is required for both mechanical and electrical performances. We studied an analysing method to find out a deformation of brittle porcelain with a thermal expansion of simulation analysis and experimental results show that cement volume growths affect severely to b mechanical failure ageing.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.16 no.28
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• pp.69-75
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• 1993

The evaluation of product may be classified by technical tests or by ergonomics assessments. If an ergonomics assessment is required, then the three types of interface dimension are available to the researcher. In this paper, we proposed the heuristic evaluation method for usability of product in the three types of interface dimension The evaluation method is used the fuzzy weighted checklist technique computerized for evaluating or comparing prototype of system and IT product.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.277-279
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• 2003

컴포넌트 기반 개발은 재사용 단위의 컴포넌트를 사용하여 소프트웨어의 중복개발을 지양하고 시스템을 효율적으로 개발한다. 또한 인터페이스를 통해 컴포넌트 배치시 내부의 수정없이 사용자의 요구에 맞게 컴포넌트를 특화하는 장치를 제공한다. 본 논문에서는 컴포넌트 가변성(Variability)을 위한 컴포넌트 Required 인터페이스를 제시한다. 분석단계에서 컴포넌트의 공통성 및 가변성 식별이 이루어졌음을 가정하고, 분석단계의 산출물인 '가변성 식별 테이블'을 수집하여 가변성을 위한 오퍼레이션 식별 및 인터페이스를 정의한다. 또한 컴포넌트 Requited 인터페이스 명세서를 제공한다. 따라서 제시된 기법은 Required 인터페이스를 구성하는 오퍼레이션의 식별부터 명세까지 체계적인 Required 인터페이스의 설계 프로세스를 제시하여 블랙박스 컴포넌트의 가변성 설정을 위한 실용적인 Required 인터페이스의 기반이 된다.

• Journal of Korea Multimedia Society
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• v.20 no.7
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• pp.1113-1128
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• 2017

This study was practiced in order to develop a textbook to improve early childhood teachers' ability to use multimedia required by kindergartens and to examine its effects. First, investigation of the status of multimedia application of early childhood teachers in kindergartens was done along with looking through their attitude and anxiety. The expertise and the multimedia education was required in early childhood education and curriculum. As a result, 15 categories and 50 subcategories under 4 themes were drawn through the procedures of qualitative analysis. The conclusions obtained through this study were the following: First, the education for multimedia application related to the tasks required in kindergartens is needed instead of the common education for multimedia application, to improve the ability to use multimedia for early childhood teachers. Second, multimedia education based on visual theory for the purpose of early childhood education, rather than common features-centered multimedia education, is helpful for the improvement of early childhood teachers' ability to use multimedia. Finally, the improvement of early childhood teachers' ability to use multimedia will be a chance to provide children with a better educational environment.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.773-780
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• 2009

Experiments on steel-concrete interface are performed to investigate and determine the mechanical roles and properties of interface parameters. The intrinsic different nature of bonded and unbonded interfaces are addressed based on the experimental observations that were obtained from two types of tests considering bonded and unbonded interfaces. The unbonded tests are performed for the specimens that are in unbonded when the initially bonded specimens are tested first. Four cases of lateral confinements including pure slip, and low and medium levels of lateral pressure are taken into account to investigate the effects of lateral confinements on interface behavior. It is shown that the maximum shear strengths, the levels of residual strengths and the Mode II fracture energy release rates are linearly related to the confinement levels. Based on the experimental evidences obtained from this study, the values of interface parameters required in a steel-concrete interface constitutive model will be presented in the companion paper.