• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.473-478
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• 2011

Welding process generates distortion and residual stress in the weldment due to rapid heating and cooling. Welding distortion and residual stress in the welded structure result in many troubles such as dimensional inaccuracies in assembling and safety problem during service. The accurate prediction of welding residual stress is thus very important to improve the quality of weldment and find the way to reduce itself. This paper presents the simulation of welding-induced residual stress analysis to examine the cause of cracking in the SUS-overlay welding specimen at FPSO Moon Pool structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.61-64
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• 2005

Recently to repair the structure of deteriorated concrete, LMC rehabilitation method is introduced. however, this method has the possible risks of brittle failure depending on bond performance of the interface. the prediction of interfacial behavior becomes essential to protect the failure. all of the studies which have been done about this field are only about material property such as strength, durability, bond. there is not enough data and studies about structural behavior and numerical analysis. therefore, in this study A flexural nonlinear analysis model of ABAQUS was proposed to predict the load-deflection response, interfacial stress, and ultimate strength. The parameter study showed that overlay thickness was a main influencing factor to the behavior of RC beam overlayed by LMC.

• Journal of Welding and Joining
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• v.29 no.3
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• pp.70-75
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• 2011

Welding process generates distortion and residual stress in the weldment due to rapid heating and cooling. Welding distortion and residual stress in the welded structure result in many troubles such as dimensional inaccuracies in assembling and safety problem during service. The accurate prediction of welding residual stress is thus very important to improve the quality of weldment and find the way to reduce itself. This paper presents the simulation of welding-induced residual stress analysis to examine the cause of cracking in the SUS-overlay welding specimen at FPSO Moon Pool structure.

• Korean Journal of Remote Sensing
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• v.10 no.2
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• pp.121-132
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• 1994

A GIS based tactical terrain analysis system named ATTAS(Army Tactical Terrain Analysis Software) has been designed and implemented to support the field commanders for enhancing the capabiliy of their unit and efficiency of weapon system. This system is designed to provide computer graphics environment in which the analyst can interactively operate the entire analyzing process such as selecting the area of interest, performing analysis functions, simulating required battlefield operation and display the results. This system can be divided into three major sections; the terrain analysis modules, utilites, and graphic editor. The terrain analysis module inclused surface analysis, line of sight analysis, enemy disposition, 3D display, radar coverage, logistic route analysis, shortest path analysis, atmospheric phenomena prediction, automated IPB (Inteligence preparation of Battlefield), and other applied analysis. A combination of 2D and 3D computer graphics techniques using the X-window system with OSF/Motif in UNIX workstation was adopted as the user interface. The integration technique of remotely sensed images and GIS data such as precision registration, overlay, and on-line editing was developed and implemented. An efficient image and GIS data management technique was also developed and implemented using Oracle Database Management System.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.5 no.3
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• pp.27-45
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• 2010

It is strongly believed that multicast will become one of the most promising services on internet for the next generation. Multicast service can be deployed either on network-layer or application-layer. IP multicast (network-layer multicast) is implemented by network nodes (i.e., routers) and avoids multiple copies of the same datagram on the same link. Despite the conceptual simplicity of IP multicast and its obvious benefits, it has not been widely deployed since there remain many unresolved issues. As an alternative to IP multicast, overlay multicast (application-layer multicast) implements the multicast functionality at end hosts rather than routers. This may require more overall bandwidth than IP multicast because duplicate packets travel the same physical links multiple times, but it provides an inexpensive, deployable method of providing point-to-multipoint group communication. In this paper we develop an efficient method applied greedy algorithm for solving two models of overlay multicast routing protocol that is aimed to construct MDST (Minimum Diameter Spanning Tree : minimum cost path from a source node to all its receivers) and MST (Minimum Spanning Tree : minimum total cost spanning all the members). We also simulate and analyze MDST and MST.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.353-361
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• 2015

The area of red tides occurences, which brings enormous damages every year, have been expanded to the coastal waters across the nation. Regarding to this trend, the development of red tide detection technology by using the GOCI (Geostationary Ocean Color Imager) of COMS lauched in 2010 has been drawn attentions of researchers. This study purposed on analyzing the frequency and density of red tides occurence by using the GOCI for detecting the southern sea, whereas targeted area. The observation has brought over the last three years (2012, 2013, and 2014) before the analysis was conducted. Followingly, the study could be resulted in extracting and revealing the hot spots of the red tides from two of analysis in the overlay and density. The distribution patterns of red tide occurrences according to those observed years has been shown in irregular characteristics and various changes. However, the analysis of hot spots, based on the frequency of the red tide occurrence, has revealed that the frequency of red tide occurences is continuously increased in the specific sea area. Therefore, it is concluded in that the continuous monitoring can contribute to predict accurate movements of red tides, so as establish systematic plans for preventing disasters.

• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.2
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• pp.27-37
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• 2001

Using satellite image and GIS, spatial distribution characteristics of black locust forest as honey plant area was identified and analyzed. Upon the result, the most suitable area for black locust forest was selected through the integration analysis of transparent overlay. The variables used for spatial analysis such as topography(elevation, aspect, slope), soil, drainage, distance from urban area, land use, meteorological elements were considered. Based on the suitability analysis, it was clarified that the integration of linear and factor combination technique is greatly efficient method for the most suitable area. In addition, Gokung, Imgo, Chungtong, Hwanam area were shown to be suitable in Young-chun Area. As the result of suitability analysis for honey plant area of black locust in Young-chun using satellite image and GIS, the present portion of potential distribution area was produced about 42.53%. The portion of most suitable area for honey plant area of black locust was about 26.77%. Finally, the total area for honey plant area of black locust in Young-chun came up to $15.79km^2$. Additionally, satellite image and GIS were expected to be significant tools for suitability analysis of honey plant complex area.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.509-511
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• 2004

This paper outlines the development of image processing system, which will allow the general users in Government and Public organizations easily to use and apply KOMPSAT EOC images in their own business. The system includes an import/export module of EOC image distributed in Hierarchical Data Format (HDF) file and various image processing analysis modules. Especially, the image mosaic and subset functions are designed to use EOC image as an image map, generating the Ortho-image module. To update the various spatial data with EOC image, some essential modules such as change detection by pattern recognition, overlay between images and vector data, and modification of vector data are implemented in the system. The system is developed based on the user request analysis of government agency, and suited for more efficient use of satellite image in public applications. Such system is expected to contribute to practical application of KOMPSAT-2 that will be launched in 2005. Further efforts will be made to accommodate the KOMPSAT -2 MSC data.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.162-172
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• 1993

In the present paper, the overall state of the arts of ice mechanics which is the most typical research topic of the artic engineering field was studied. And also, ice loads genrated by ice-structure interaction were estimated using numerical approach. The effects of viscous property of ice sheets to the ice load were investigated. The time dependent deformation behaviors of ice was modeled by visco-plastic problem using the finite element formalism. Constitutive model representing the material properties of ice was idealized by comblned rheological model with Maxwell and Voigt models. Numerical calculations for the bending and crushing behavior of ice sheet which are the most typical interaction modes between ice sheets and structures were carried out. The time dependent viscous behaviors of ice sheets interaction forces acting on structures were analyzed and the results were studied in detail.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.8
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• pp.10-19
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• 1997

In this paper, perfodrmance of matched-filter (MF) acquisition scheme is analyzed for a direct-sequence/code-division-multiple-access (DS/CDMA) system in a microcellular environment. Mean acquistion time is used as a performance measure. It is demonstrated that acquisition performance is enhanced using interference suppression filter in a Rician fading channel. To apply for multiuser environments, multiple access interference is considered in the performance analysis. From the numerical results, it is shown that mean acquistion time decreases with the increasing SNR/chip, and acquisition performance is improved as the number of taps of interference suppression filter. It is also shown that mean acquisition time increases with the number of users in the system, and acquistion performance is degraded as the icrease of narrowband interference bandwidth. The analysis in this paper can be applied to a DS/CDMA overlay environment.