• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.252-256
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• 1999

In this research, the performance predictions of the submersible mixer were investigated. The variation of the performance characteristics by changing the impeller design parameters were discussed through the flow calculation results by using a commercial program, FLUENT. The performance of the submersible mixers is related to the velocity diffusion profiles downstream of the impeller and also the required input motor power to mix the fluid. In this study, the various design parameters such as the number of blade, the hub and tip diameters, the impeller blade profiles and revolution speed of the blades were taken for the fixed values. The blade sweep direction, the chord length distribution along with the radius of the blade and the inlet blade angle were changed to make different testing models. The flow calculation results show the effect of the changed design parameters on the performance of the submersible mixers and also give some helpful information for designing more efficient submersible mixers.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.520-525
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• 2003

A numerical investigation was performed to determine the effect of airfoil on the optimum flap height using NACA0015 Wells turbine. The five double flaps which have 0.5% chord height difference were selected. A Wavier-Stokes code, CFX-TASCflow, was used to calculate the flow field of the Wells turbine. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the 3-D numerical grid is based upon that of an experimental test rig. This paper tries to analyze the optimum double flap of Wells turbine with the numerical analysis.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.313-324
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• 1992

Two-dimensional Navier-Stokes code has been developed for analysis of turbomachinery blade rows and other internal flows. The Navier-Stokes equations are written in a Cartesian coordinate system, then mapped into a generalized body-fitted coordinate system. All direction of viscous terms are incorporated and turbulent effects are modeled using the Baldwin-Lomax algebraic model. Equation are discretized using finite difference method on the C-type grids and solved using implicit LU-ADI decomposition scheme. Calculations are made at a VKI turbine cascade flow in a transonic wind-tunnel and compared to experimental data. Present numerical scheme is shown to be in good agreement with the previous experimental results and simulates the two-dimensional viscous flow phenomena.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.165-168
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• 2015

To measure laminar burning velocity in methane/air/ethylene mixture flame, propagating centrally ignited spherical premixed flame to radial direction was measured by high-speed schlieren images with elevated pressure. In this study, The experimentally measured unstretched laminar burning velocities of methane was compared with GRI mech 3.0 to validate experimental data and choose the radius range, respectively. numerical prediction using the PREMIX code with GRI mech 3.0, USC mech II,, and Wang mech were evaluated through comparison with experimental burning velocity with consideration of extrapolation on linear/nonlinear model.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.111-116
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• 2001

A practical scheme to reduce failure of the PCB(Printed Circuit Board) of a monitor is introduced using deformed mode shape under mechanical shock. When the monitor is given critical shock loads, cracks are commonly initiated at the tip of a hole on the PCB. Accordingly, a deformed mode shape of the PCB is obtained using a FEM code to define a weak point on the PCB under mechanical shock, and then the position and direction of the hole is determined to prevent the failure at the critical mode shape. Also, the stress intensity factor around the weak point on the PCB is calculated to check the possibility of fracture by normal tensile stress. In conclusion, present research is useful to assist the practical design of components-layout on the PCB.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3207-3216
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• 2021

Three-dimensional structures of a vortical flow field and heat transfer characteristics in a partially blocked 7-pin fuel assembly mock-up of sodium-cooled fast reactor have been investigated through a numerical analysis using a commercial computational fluid dynamics code, ANSYS CFX. The simulation with the SST turbulence model agrees well with the experimental data of outlet and cladding wall temperatures. From the analysis on the limiting streamline at the wall, multi-scale vortexes developed in axial direction were found around the blockage. The vortex core has a high cladding wall temperature, and the attachment line has a low cladding wall temperature. The small-scale vortex structures significantly enhance the convective heat transfer because it increases the turbulent mixing and the turbulence kinetic energy. The large-scale vortex structures supply thermal energy near the heated cladding wall surface. It is expected that control of the vortex structures in the fuel assembly plays a significant role in the convective heat transfer enhancement. Furthermore, the blockage plate and grid spacer increase the pressure drop to about 36% compared to the bare case.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.593-600
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• 2009

In Korea, the government has developed SEUMTER, an administration system for building related public service, to facilitate and promote the electronic submission and permission activities. SEUMTER is progressing legality system based on 2D drawing for building administration permission service. However, there are a lot of problems related to legality system owing to complexity of Korea regulation relation and structure, inefficiency of legality system based on 2D drawing, duplication examination of document (soliciting forms for civil affairs) and drawing. Therefore, the purpose of this study is to develop legality system for building administration permission service based on BIM in Korea. To achieve this purpose, the authors have investigated permission procedure and regulation structure that is used in current building administration permission and suggested permission procedure and regulation structure for legality system based on BIM. In addition, the authors have investigated element technologies (for examples, method of structured regulation, BIM model checker, Viewer, etc) for legality system based on BIM. Finally, the authors have suggested strategy and hereafter direction for application of legality system based on BIM.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.172-175
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• 2021

4차 산업혁명이 시작된 이래로 다양한 산업 분야에서 AI가 활용되고 있고, 그 중에서도 컴퓨터 비전 분야에서 딥러닝 기술이 각광받고 있다. 하지만 딥러닝 기술은 높은 전문 지식이 요구되어 관련 지식이 없는 일반인들은 활용하기 어렵다. 본 논문에서는 AI 관련 배경지식이 없는 사용자들도 UI를 통해 쉽게 이미지 분류 모델을 학습시킬 수 있는 노 코드 플랫폼에 관하여 기술하고, django 프레임워크를 이용해 웹 개발과 딥러닝 모델 학습을 통합 개발을 위한 아키텍처와 방향성을 제시하고자 한다. 사용자가 웹서버에 업로드한 이미지들을 웹 인터페이스를 통해 라벨링 하여 학습 데이터를 생성한 후, 이 데이터를 사용하여 모델을 학습시킨다. CNN 모델에 데이터를 학습시키는 과정과 생성된 모델 기반으로 이미지 예측하는 모듈을 통해 전문지식이 없는 사용자가 딥러닝 기술에 대해 쉽게 이해하고 이용하는 것을 기대할 수 있다.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.155-164
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• 2011

As Information & Communication Technology is developed in fast speed, the educational field undertakes many changes in utilizing Information Technology(IT). As the smart phone's educational utilization brings many positive effects, so many people are interested in such educational application programs. The e-textbooks or learning contents based on the web have shown some limits in being utilized as main learning materials in school field. So this study identified such limits, and suggested a new direction for professional education by integrating mobile and QR code technologies with existing textbooks to realize a new book-type E-Textbook model. And this study purposed for students to participate in their classes more easily through making open-education environment for students studying specialized subjects and by applying new teaching-learning methods inducing more interest in them. Of course, this study's ultimate purpose is to raise students' learning ability about specialized subjects, and further, to improve their self-directed learning abilities with increased interests in classes. As the result operating this model, it was found that this model had enough learning effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.88-96
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• 2017

The construction standards in Korea consist of design standards and specifications. They are provided by the national transportation electronic information center in file format, not in a DB, which may lead to their incomplete utilization and versatility, such as a lack of history management and reference functions. This also makes it difficult to cross-refer to standards and manage revision history. In this study, we developed a code management system for the national construction standards by analyzing domestic and overseas related systems, in order to pinpoint the problems in the current system and its development direction and, thus, to suggest a detailed plan for the design and implementation of a code management system. The developed system comprises four subsystems, namely a construction standards making system, construction standards service system, construction standards maintenance system and construction standards portal system. The results of this study are expected to improve the user's convenience by facilitating the revision, operation and history management of the complex and various construction standards, and to provide high-quality national construction standards by effectively supporting the revision and operation of the national construction standards with minimum duplication and conflicts.