• Journal of the Korean Ceramic Society
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• v.31 no.6
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• pp.587-594
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• 1994

(Ba, Sr)TiO3-based PTCR ceramics were sintered and cooled down with various cooling conditions in the air. AES was applied to investigate the composition change in the grain boundary and bulk area of oxidatively cooled samples. Ba component was deficit in grain boundary region, while oxygen was abundant than bulk region. The discrete changes of oxygen binding energies were confirmed in the grain boundary region of the heavily oxidized samples. It was supposed that the large binding energy shift resulted from the oxidation of the segregated Mn in grain boundary region and this idea was supported by the DV-X$\alpha$ molecular energy simulation.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.11-18
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• 2003

The soot formation and oxidation characteristics with different radiation boundary conditions have been studied experimentally in a co-flow ethylene/air laminar diffusion flame. The boundary conditions are two cases, one is a fully refractive radiation boundary condition by a polished aluminum cylinder(AL) and the other is a fully absorbing radiation boundary condition by a black body cylinder(BB). The AL case compared with BB condition show the lower inception point, denser soot volume fraction, wider and longer annular soot area owing to the reabsorption of radiating energy.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.11
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• pp.637-642
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• 2000

IEEE 1149.1 boundary scan architecture is used as a standard in board-level system testing. The simplicity of this architecture is an advantage in system testing, but at the same time, it it makes a limitation of applications. Because of several problems such as 3-state net conflicts, or ambiguity issues, interconnect testing for multi-drop multi-board systems is more difficult than that of single board systems. A new approach using IEEE 1149.1 boundary scan architecture for multi-drop multi-board systems is developed in this paper. Adding boundary scan cells on backplane bus lines, each board has a complete scan-chain for interconnect test. This new scan-path insertion method on backplane bus using limited 1149.1 test bus less area overhead and mord efficient than previous approaches.

• Wind and Structures
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• v.7 no.2
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• pp.131-144
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• 2004

A technique for the simulation of atmospheric boundary layers in wind tunnels is developed and tested experimentally. The device consists of a grid made of seven horizontal and vertical evenly distributed bars in which air injection holes are drilled in order to influence the flow in the wind tunnel. The air flow in each bar can be controlled independently. Firstly, the device is used together with a rough carpet, which covers the test section floor, in order to simulate the boundary-layer characteristics over an open rural area. Hot-wire measurements, performed at different positions in the test-section, show the capability of the grid in generating the required boundary layer. An acceptable agreement with statistical values of mean velocity and turbulence profiles has been achieved, together with a good span-wise homogeneity. The results are also compared with those of a passive simulation technique based on the use of spires.

• Journal of the Korean Society of Combustion
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• v.18 no.3
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• pp.31-37
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• 2013

Numerical simulations are conducted to investigate the feature of spontaneous ignition of hydrogen within a certain length of downstream tube released by the failure of pressure boundaries of various geometric assumption. The results show that the ignition feature can be varied with the shape of pressure boundary. The ignition at the contact region are developed at the spherical pressure boundaries due to multi-dimensional shock interactions, whereas the local ignition is developed in limited area such as boundary layer at the planar pressure boundary conditions. The spontaneous ignition inside the tube can be generated from the reaction region of only boundary layer regardless of existence of the reaction of core region.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.4
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• pp.293-299
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• 1985

This paper describes an economical prediction procedure for heat transfer phenomenon through a channel containing an abrupt asymmetric expansion in flow cross-seetional area. Numerical solutions for the flow field are obtained by the finite difference numerical method applied to the modified boundary layer equations. Modified boundary energy equation is used to analyze heat transfer as modified boundary momentum equation. Predictions of the method compare very favorable with exprimental data. Results of this study by modified boundary layer equation are as follows : 1. The computation time required for the scheme is at least an order of magnitude less than for the numerical solution of the full Navier-stokes and Energy eguations. 2. In laminar flow, the maximum heat transfer occurs downstream of the reattachment point.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.53-68
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• 2020

The Cadastral Renovation is a National project to investigate and survey the registration of Cadastral Record and replace the existing Cadastral Record with a new Cadastral Record by digital, and to correct the registration of Cadastral Record if the registration of Cadastral Record does not match the actual status of the land. The Business Period generally takes about one year and six months to two years. The time required is getting longer due to problems that occur in the course of the Adjustment amount after the cadastral resurvey survey due to complex structure and internal conflict due to the interest between landowners. After Boundary Decision of the real boundary, the land area is confirmed by the landowners, and the cadastral office is to settle the Cadastral Renovation by calculating the Adjustment amount according to the confirmed area and the increase and decrease of the cadastral area. Therefore, the solution plan was suggested so that reasonable Adjustment amount can be applied through empirical research applied to the time of calculation of Adjustment amount and the method of calculation of Adjustment amount. The improvement method showed the expected effect that can lead the agreement with the landowner to the shortest period, and it was also possible to set the real boundary that meets the purpose of the Cadastral Renovation. This study suggests improvements in the method of calculating standard Adjustment amount, the method of imposing Adjustment amount, and the method of boundary adjustment that does not impose adjustment amount through the cadastral Renovation and parallel studies, and it is expected that the Cadastral Renovation will be completed by 2030.

• Journal of Information Technology Services
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• v.19 no.5
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• pp.33-47
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• 2020

In recent years, due to the demand for operating efficiency and cost reduction of industrial facilities, remote access via the Internet is expanding. the control network accelerates from network separation to network connection due to the development of IIoT (Industrial Internet of Things) technology. Transition of control network is a new opportunity, but concerns about cybersecurity are also growing. Therefore, manufacturers must reflect security compliance and standards in consideration of the Internet connection environment, and enterprises must newly recognize the connection area of the control network as a security management target. In this study, the core target of the control system security threat is defined as the network boundary, and issues regarding the security architecture configuration for the boundary and the role & responsibility of the working organization are covered. Enterprises do not integrate the design organization with the operation organization after go-live, and are not consistently reflecting security considerations from design to operation. At this point, the expansion of the control network is a big transition that calls for the establishment of a responsible organization and reinforcement of the role of the network boundary area where there is a concern about lack of management. Thus, through the organization of the facility network and the analysis of the roles between each organization, an static perspective and difference in perception were derived. In addition, standards and guidelines required for reinforcing network boundary security were studied to address essential operational standards that required the Internet connection of the control network. This study will help establish a network boundary management system that should be considered at the enterprise level in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.2
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• pp.111-119
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• 2013

It is essential and fundamental to extract boundary information of target object via massive three-dimensional point data acquired from laser scanner. Especially extracting boundary information of manmade features such as buildings is quite important because building is one of the major components consisting complex contemporary urban area, and has artificially defined shape. In this research, extended ${\chi}$-algorithm using geometry information of point data was proposed to extract boundary information of building from three-dimensional point data consisting building. The proposed algorithm begins with composing Delaunay triangulation process for given points and removes edges satisfying specific conditions process. Additionally, to make whole boundary extraction process efficient, we used Sweep-hull algorithm for constructing Delaunay triangulation. To verify the performance of the proposed extended ${\chi}$-algorithm, we compared the proposed algorithm with Encasing Polygon Generating Algorithm and ${\alpha}$-Shape Algorithm, which had been researched in the area of feature extraction. Further, the extracted boundary information from the proposed algorithm was analysed against manually digitized building boundary in order to test accuracy of the result of extracting boundary. The experimental results showed that extended ${\chi}$-algorithm proposed in this research proved to improve the speed of extracting boundary information compared to the existing algorithm with a higher accuracy for detecting boundary information.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.460-465
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• 2001

Pollutant load using unit load method is calculated by simply equation, especially, very useful in the area that didn't exist about water quality data. However, it takes long time to calculate pollutant load with area in which there is various pollutants and if the boundary of a basin altered, the work of calculation about pollutant load must be begun from the first again. Therefore, a Total Daily Load Program(TDLP) was developed to calculate pollutant load automatically in rural area. The TDLP includes a geographic information system(GIS), relational database system(RDBS), User Interface. This Program can provide user with creating a boundary of the basin that user is concerned with to satisfy the water quality regulations and calculating daily load for various pollutants. The effort was conducted to apply the developed TDLP to calculating pollutant load in rural basin called Bok-ha river.