• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.15-20
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• 2008

High-spatial resolution remote sensing satellites (IKONOS-2, QuickBird and KOMPSAT-2) have provided low-spatial resolution multispectral images and high-spatial resolution panchromatic images. Image fusion or Pan-sharpening is a very important in that it aims at using a satellite image with various applications such as visualization and feature extraction through combining images that have a different spectral and spatial resolution. Many image fusion algorithms are proposed, most methods could not preserve the spectral information of original multispectral image after image fusion. In order to solve this problem, modified induction technique which reduce the spectral distortion of fused image is developed. The spectral distortion is adjusted by the comparison between the spatially degraded pan-sharpened image and original multispectral image and our algorithm is evaluated by QuickBird satellite imagery. In the experiment, pan-sharpened image by various methods can reduce spectral distortion when our algorithm is applied to the fused images.

• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.227-239
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• 2014

This study aims to evaluate performance of various image fusion methods based on the spectral responses of high-resolution optical satellite sensors such as KOMPSAT-2, QuickBird and WorldView-2. The image fusion methods used in this study are GIHS, GIHSA, GS1 and AIHS. A quality evaluation of each image fusion method was performed with both quantitative and visual analysis. The quantitative analysis was carried out using spectral angle mapper index (SAM), relative global dimensional error (spectral ERGAS) and image quality index (Q4). The results indicates that the GIHSA method is slightly better than other methods for KOMPSAT-2 images. On the other hand, the GS1 method is suitable for Quickbird and WorldView-2 images.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.1
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• pp.63-73
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• 2024

NeQuick G is the ionosphere model utilized by Galileo single-frequency users to estimate the ionospheric delay on each user-satellite link. The model is characterized by the effective ionization level (Az) index, determined by a modified dip latitude (MODIP) and broadcast coefficients derived from daily global space weather observations. However, globally fitted Az coefficients may not accurately represent ionosphere within local area. This study introduces a method for regional ionospheric modeling that searches for locally optimized Az coefficients. This approach involves fitting TEC output from NeQuick G to TEC data collected from GNSS stations around Korea under various ionospheric conditions including different seasons and both low and high solar activity phases. The optimized Az coefficients enable calculation of the Az index at any position within a region of interest, accounting for the spatial variability of the Az index in a polynomial function of MODIP. The results reveal reduced TEC estimation errors, particularly during high solar activity, with a maximum reduction in the RMS error by 85.95%. This indicates that the proposed method for NeQuick G can effectively model various ionospheric conditions in local areas, offering potential applications in GNSS performance analyses for local areas by generating various ionospheric scenarios.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.1
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• pp.1-11
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• 1999

The three-dimensional laminar mixed convection flow between the conductive printed circuit boards. on which the heat generating rectangular blocks are uniformly distributed, has been examined in the present study. The flow and heat-transfer characteristics are assumed to be pseudo periodic in the streamwise direction and symmetric in the cross-stream direction. Using an algorithm of SIMPLER, the continuity equation. the Navier-Stokes equations and the energy equation are solved numerically in the three-dimensional domain Inside the channel. The convective derivative terms are discretized by the QUICK scheme to accurately capture the flow field. The flow and the heat transfer characteristics are thoroughly examined for various Re and Gr.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.6
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• pp.12-20
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• 2008

The efficient plan and numerical methods for development of the interior ballistics code have been investigated. The schemes of the numerical code for the moving boundary with the projectile movement have been compared and verified through the free piston motion problem. The combustion of solid propellants and the pressure gradient in the chamber by the porosity effect have been predicted based on the numerical calculation of the initial combustion of the interior ballistics. Computerization techniques of the fundamental schemes and plans for development of the numerical analysis code for the interior ballistics have been obtained.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.6
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• pp.97-104
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• 1999

An experimental investigation was carried out to study the feasibility of using the stabiliozed sludge, as a backfill and cutoff-water materials for embankment structures. For stabilizing of sludge, hydrated lime and quick lime were used as additive, and a series of tests were performed on the sludge and the stabilized sludge to examine their physical and mechanical properties , compaction, compressive strength, hydraulic conuctivity and consolidation characteristics. From the test results, physical and mechanical properties of the stabilized sludge were improved as compared with the sludge. Especially from the viewpoint of physcial property, consolidation or settlement and cutoff-water, quick lime is more effective than the hydrated lime as a stabilization addtive. But, viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as a atabilization additive. As a result of this study, it was found that the stabilized sludge can be developed the backfill and cutoff-water materials, improved the stabilizing method of sludge.

• KIISE Transactions on Computing Practices
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• v.21 no.3
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• pp.239-246
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• 2015

QR(Quick Response) Code has been developed to provide greater storage capacity and more functionality compared to 1D bar codes. With the emergence of increasingly mobile devices equipped with cameras such as smart-phones and tablets, QR codes have become very popular and more important in mobile businesses. Typically, most QR codes are used as a URL link for redirecting users to webpages. However, the URL based QR codes are required to be connected over the internet and to be run a server. This can incur unnecessary traffics in the Internet. Furthermore, it is not suitable for the country lagging behind others in its network infrastructure. In this paper, we propose a server-less ${\mu}$-webpage to provide mobile web services and be optimized for the capabilities and limitations of QR Code. We have implemented the ${\mu}$-webpage in Android, and the results showed that the proposed mechanism can provide web-services without requiring extra servers or incurring mobile traffic data compared to the URL-based QR Codes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.6
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• pp.170-176
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• 2018

Recently, weapon system requires personal protection products due to the explosion of rapid-fire explosion, which is considered to be multi threat in modernization, complication and war against terrorism. However, the conventional Korean military bullet protection helmets are not suitable for wearing convenience and combatant interoperability in terms of ergonomic. In this paper, we propose a suitable 3D Scanning method for the head, and compare the measured 3D dimension with the existing 2D measurement value to identity the reliability. Reverse engineered soldier head using the quick surface method was realized with a perfect free-form surface and satisfactory tolerance range (${\pm}0.2mm$). Through the comparison of 3D and 2D measured head dimensions, the absolute error value was 0.73 mm on average and relative error was 0.35 %, confirming the high accuracy of the 3D scan modeling. Also, quick surface method using 3D scanner is suggested a fast and accurate skill for ergonomics in obtaining the head modeling needed for military's personal bullet protection helmet design.

• Proceedings of the Korea Society of Design Studies Conference
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• 2002.11b
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• pp.140-141
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• 2002

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.187-190
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• 2006

본 연구에서는 QuickBird 도심지역 영상을 이용하였으며, 텍스쳐영상생성기법과 웨이브릿 기법을 이용하여 생성시킨 웨이브릿 기반 텍스쳐 융합 영상(이하 융합영상)을 원본영상의 새로운 밴드로 추가시켜 분류작업을 수행하였다. 이외에도 비교분석을 위하여 원본영상에 텍스쳐 영상을 추가시킨 영상과, 텍스쳐와 융합영상을 모두 추가시킨 영상을 이용하여 분류작업을 수행하였다. 분류에는 ISODATA 무감독분류 기법을 사용하였으며, 텍스쳐 영상과 융합영상을 같이 추가시킨 영상을 이용하였을 때 분류정확도가 가장 많이 향상되는 것으로 나타났다.