• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.996-1007
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• 2019

We investigated the influence of the aspect ratio (H/R) of the oxide layer on the reactor vessel heating in three-layer configuration. Based on the analogy between heat and mass transfers, we performed mass transfer experiments to achieve high Rayleigh numbers ranging from $6.70{\times}10^{10}$ to $7.84{\times}10^{12}$. Two-dimensional (2-D) semi-circular apparatuses having the internal heat source were used whose surfaces of top, bottom and side simulate the interfaces of the oxide layer with the light metal layer, the heavy metal layer, and the reactor vessel, respectively. Multi-cell flow pattern was identified when the H/R was reduced to 0.47 or less, which promoted the downward heat transfer from the oxide layer and possibly mitigated the focusing effect at the upper metallic layer. The top boundary condition greatly affected the natural convection of the oxide layer due to the presence of secondary flows underneath the cold light metal layer.

• Journal of the Korean Institute of Educational Facilities
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• v.13 no.2
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• pp.50-60
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• 2006

In search of the improvement plan for elementary schools which aims at the efficient application of new educational programs according to the introduction of the 7th National Curriculum, the analysis results for the spatial configuration regarding the modernized elementary schools in Busan City are as follows: 1) The analysis of expansion in the building area reveals that the building area per classroom has been increased from $200m^2$ in 1995 to $350m^2$ in 2005 based on the data gathered from the constructed schools during that period. 2) While the ratio of classrooms per the gross school area has been decreased from 35% in the late 1990s to 20% in the 2000s, the entire school size continue to become larger, which is considered as desirable change. 3) New construction and addition of special classrooms and multi-purpose spaces have continued to be increased. Multi-purpose spaces were positively considered in the early 2000s, but recently built schools tend to limit the construction of multi-purpose spaces only to lower grades' space or not to obtain them owing to the analysis that its utilization is limited. 4) Most schools constructed after 1999 are equipped with dining hall and multi-purpose halls, and show the increase in their sizes. Especially, dining hall tend to be located on the upper floors for better environmental conditions.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.12-18
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• 2001

The objective of the present work is to examine the effect of inclined angle of channel with multi heat source on thermal stability of electronic equipment. The heat sources are mounted on both sides of channel walls by two kinds of configuration such as the zig-zag md symmetric on. Conductive heat transfer was estimated by using of thermocouples and heat flux sensor. Thus, convective heat transfer and mean Nusselt number could be obtained. With increased inclined angle, the convective heat transfer coefficient was decreased. When inclined angle was smaller than 30 degree, The average Nusselt number of Big-zag configuration was larger than that of symmetric. Furthermore, when protruding ration was 0.082, the temperature was strongly affected by inclined angle. whereas, when protruding ration was 0.25, the temperature was strongly affected by heat source configuration.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.3
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• pp.385-392
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• 2009

This study aims to methodology a system which is able to monitor and configuration management of long span bridge in real time using multi GPS. Through setting up many GPS at the important points of long span bridge and measuring displacement in real time, over all 3D configuration of bridge could be analyzed. Behavior analyzing system developed in this study is able to digitize and visualize the overall and points displacement of bridge and deal with events actively. Also it is able to calculate statistical data related to analyze behavior through the constricting database of measuring data.

• Smart Structures and Systems
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• v.30 no.6
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• pp.583-599
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• 2022

In this paper, a multi-objective wireless sensor network configuration optimization method is proposed. The proposed method aims to determine the optimal information and lifespan wireless sensor network for structural health monitoring of large-scale infrastructures. In particular, cluster-based wireless sensor networks with multi-type of sensors are considered. To optimize the lifetime of the wireless sensor network, a cluster-based network optimization algorithm that optimizes the arrangement of cluster heads and base station is developed. On the other hand, based on the Bayesian inference, the uncertainty of the estimated parameters can be quantified. The coefficient of variance of the estimated parameters can be obtained, which is utilized as a holistic measure to evaluate the estimation accuracy of sensor configurations with multi-type of sensors. The proposed method provides the optimal wireless sensor network configuration that satisfies the required estimation accuracy with the longest lifetime. The proposed method is illustrated by designing the optimal wireless sensor network configuration of a cable-stayed bridge and a space truss.

• Journal of the Korean Data and Information Science Society
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• v.14 no.2
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• pp.237-245
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• 2003

MDS(multi-dimensional scaling) for preference data is a graphical tool which usually figures out how consumers recognize, evaluate certain products. This article is mainly concerned with an optimal scaling for MDS when target configuration is available. Rotation of axis and SUR(seemingly unrelated regression) methods are employed to get a new configuration which is obtained as close to the target as we can. Methodologies developed here are also illustrated via a real data set.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.258-261
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• 2003

In this study, finite element analysis for multi-stage deep drawing process of rectangular configuration with extreme aspect ratio is carried out especially for the blank design. The analysis of rectangular deep drawing process with extreme aspect ratio is likewise very difficult with respect to the design process parameters including the intermediate die profile. In order to solve the difficulties, numerical approach using finite element method is performed in the present analysis and design. A series of experiments for multi-stage rectangular deep drawing process are conducted and the deformed configuration is investigated by comparing with the results of the finite element analysis. Additionally, to minimize amount of removal material after trimming process, finite element simulation is applied for the blank modification. The analysis incorporates brick elements for a rigid-plastic finite element method with an explicit time integration scheme using LS-DYNA3D.

• Journal of computational fluids engineering
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• v.12 no.4
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• pp.28-37
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• 2007

In this study, a multi-block structured grid deformation code based on a hybrid of a transfinite interpolation algorithm and spring analogy was developed. The configuration was modeled by a Bezier surface. A combination of the spring analogy for block vertices and the transfinite interpolation for interior grid points helps to increase the robustness and makes it suitable for distributed computing. An elliptic smoothing operator was applied to the block faces with sub-faces in order to maintain the grid smoothness and skewness. The capability of this code was demonstrated on a range of simple and complex configurations including an airfoil and a wing-body configuration.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.753-760
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• 2009

As it becomes increasingly important that Internet access is available anywhere at any time, providing MANET (Mobile Ad-Hoc Network) with the Internet access attracts more attention. The existing DHCP (Dynamic Host Configuration Protocol) address configuration schemes require message exchanges between MANET nodes and the DHCP server through multi-hop routes. Messages can be easily dropped in the wireless multi-hop communication environment and the address configuration may be instable and need long delay. In this paper, we propose a new address configuration scheme using the concept of address pool allocation. In the proposed scheme, the DHCP server assigns a part of its address pool to a node instead of a single address and the node can assign a part of its own address pool to its neighbor nodes. Through simulation studies, we show that our scheme yields about 77% of the address configuration delay and 61% of the control message overhead of the existing DHCP based mechanism.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.1
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• pp.36-42
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• 2007

A low-power compact driver for multistandard physical layer is presented. The proposed driver achieves low power and small area through the voltage-mode driver with trans-impedance configuration and the novel hybrid driver,. In the voltage-mode driver, a trans-impedance configuration alleviates the problem of limited common-mode range of error amplifiers and the area and power overhead due to pre-amplifier. For a standard with extended output swing, only current sources are added in parallel with the voltage-mode driver, which is named a 'hybrid driver'. The hybrid architecture not only increases output swing but reduces overall driver area. The overall driver occupies $0.14mm^2$. Power consumptions under 3.3-V supply are 24.5 mW for the voltage-mode driver and 44.5 mW for the hybrid driver.