• Journal of KIISE:Computer Systems and Theory
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• v.36 no.6
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• pp.511-520
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• 2009

In this paper, we present a new iso-density surface reconstruction scheme based on a hierarchy on the input volume data and the output mesh data. From the input volume data, we construct a hierarchy of volumes, called a volume pyramid, based on a 3D dilation filter. After constructing the volume pyramid, we extract a coarse base mesh from the coarsest resolution of the pyramid with the Cell-boundary representation scheme. We iteratively fit this mesh to the iso-points extracted from the volume data under O(3)-adjacency constraint. For the surface fitting, the shrinking process and the smoothing process are adopted as in the SWIS (Shrink-wrapped isosurface) algorithm[6], and we subdivide the mesh to be able to reconstruct fine detail of the isosurface. The advantage of our method is that it generates a mesh which can be utilized by several multiresolution algorithms such as compression and progressive transmission.

• Journal of the Korean Society for Railway
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• v.14 no.6
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• pp.501-506
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• 2011

The study and techniques of system engineering have been applied to various fields including space-air, national defense division in advanced countries. Korea is currently in the early stages of introducing system engineering scheme in railway system and national defense division restrictedly. As theory and application of system engineering covers a wide scope, documents management and requirement analysis technology applied to establishment of standard and core unit development of the research target. The techniques which are historical management and trace among standards for establishment of standard are introduced using SE tools and participating agencies shared the information by constructing of database from all documents which are generated from the project. Through the functional analysis of the requirements for the intelligent station monitoring system in basic design stage, established requirements are verified and will be made official announcement as standard of the intelligent station monitoring system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.2
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• pp.183-194
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• 2011

Synthetic aperture radar (SAR) is widely used because of high resolution imaging capability in all weather and day/night condition. In this paper development of Spotlight SAR simulator is proposed for image quality analysis. Proposed SAR simulator is based on the SAR system design parameters so that SAR image performance can be expected which is essential throughout the full system development procedure from the initial concept design stage to the final in-flight calibration and validation stage. The raw data of ideal point target is first generated by taking account of the flight and imaging geometry and the various SAR system design parameters, and the Spotlight image formation algorithm is implemented in order to obtain the point target response. Finally the image quality of the generated raw data is analyzed in terms of spatial resolution, peak to sidelobe ratio and integrated sidelobe ratio.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.4
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• pp.160-166
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• 2019

Cerium oxide ($CeO_2$, often called as Ceria) is one of the valuable rare earth oxide materials, which has been widely used for high temperature applications such as solid oxide fuel cells, automotive three-way catalysts and oxygen storage capacity. Considering those application, it is important to improve high redox and thermal stability with high surface morphology because the high surface area of $CeO_2$ could improve the catalytic reactivity at high temperature conditions. Herein we successfully fabricated hierarchical flower-like $CeO_2$ deposited via controlling pathway of precipitation reaction to supply carbonate ion lead to the flower-like morphology. The hexagonal lattice system of precipitated precursor shows better thermal stability then orthorhombic one during thermal cycling condition.

• Journal of the Daesoon Academy of Sciences
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• v.19
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• pp.47-80
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• 2005

고구려는 지리적인 조건으로 말미암아 삼국 가운데 가장 먼저 불교를 수용할 수 있었으며 5세기부터 7세기사이에 고구려의 불교문화가 백제, 신라와 고대 일본에 전해져 동아시아 전체에 보급되었다. 불교 전래 당시부터 고구려 왕실이 열성적으로 불교를 신봉한 일은 충분히 주목할 가치가 있는데, 왜냐하면 중앙 집권적 국가로 전환을 시도하던 때 마침 불교의 사회적 정치적 가치를 인식하게 되었기 때문이다. 불교와 왕권이 상호 관계를 강화하는 쪽으로 힘을 결집시켰는데, 왕실은 불교에 대해서 후한 지원을 아끼지 않았으며, 불교는 전륜성왕, 혹은 우주를 지배하는 자, 미륵 그리고 보살 등 모티브의 상징적 중요성을 통치자에게까지 확대시킴으로써 통치자의 지위를 신성시하는 이념적 기틀을 제공하였던 것이다. 이런 맥락에서 볼 때 불교를 받아들인 후에 세워진 비문들이 왕명 앞에 성(聖) 자를 붙여 왕의 지위를 신성화하는 의미를 나타내고 있다는 점은 우연의 일치가 아니다. 4세기말 국가 차원에서 불교를 수용한 고구려와 6세기초 법흥왕 당시의 신라는 시대적인 차이가 있으나, 국가 발전의 같은 단계에 서있었기 때문에 이 두 나라의 초기 불교 정책에 많은 유사점을 찾을 수 있다 고구려에서 거칠부와 더불어 신라로 넘어 온 혜량법사가 진흥왕 12년에 처음 개최된 백고좌강회는 《인왕경》에 입각한 것이며, 이 법회가 신라인의 사상적 통합과 진흥왕의 위업을 향상하는 데 기여하였다고 여겨진다. 그리고 진흥왕이 말년에 승복을 입고 법운이라는 법호를 택했는데 여기서 주목할만한 것은 법운(法雲)이 《십지경》에서 말하는 보살의 수행 최종 단계 그것에서 따온 것이며, 《십지경》은 이미 고구려에 익히 알려졌을 것이었다.신라 화랑이 미륵의 현현으로 여겨졌다 함은 일찍부터 지적되어 온 것입니다만 이 논문에서, 그것은 북중국에서 5·6세기경 유행한 그리고 소미륵으로 간주된 월광동자 (月光童子)신앙이 고구려를 통해 남하여 화랑의 사상적인 바탕이 됐다는 것으로 이해하였다. 그 증거로 《수라비구월광동자경》에 나타난 용어와 고대 한반도의 지명을 들 수 있는데 이 경은 고구려의 선인(仙人) 사상 및 신라의 화랑을 간접적으로 직결시킨다는 점도 염두 할 필요가 있다.

• Archives of design research
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• v.16 no.2
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• pp.57-66
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• 2003

In order to develop color image, color simulation based on data processing techniques has been developed and applied to data interpretation tools or product design supporting systems. It has been a commonmethod to use image key words to search for data and provide color coordination samples that determine computer combination in computerized support systems until recently. However, this method does not reflect system designers and users taste or preference on making final choices of color coordination samples because the database was designed based on an assumption of standardized group that was established database from large scaled image evaluation research. In this study, we suggest a color coordination simulator that supports designer's final decision-making procedure on sample groups through the simulation of various color combination. The simulator allows communications with the system to explore a designer's color combination taste and preference, and provides a user for an efficient environment to judge the optimum result. The color coordination simulator was designed based upon Dual mapping model derived from a designer's thought process, and four steps of operations longrightarrowdefining color concept longrightarrowmaking color sample groupslongrightarrow simulation-determining ranking among final combination samples - will be assisting color design process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.973-980
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• 2009

Many studies which have been done for efficient installation and management of wireless sensor networks (WSN) include energy savings, key managements and sensor deployments. Sensor deployment problem is one of the most important and fundamental issues among them in that the topic is directly related with the system cost and performance. In this paper, we suggest a sensor deployment scheme that reduces the system cost of WSN while satisfying the fundamental system requirements of connectivity between sensor nodes and sensing coverage. Using graphical information system(GIS) which contains region-dependent information related with connectivity condition, the initial positions of sensors in the procedure simulated annealing (SA) are determined. The GIS information helps in reducing system cost reduction not only at the initial deployment of SA but also at the final deployment of SA which is shown by computer simulations.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.4
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• pp.286-294
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• 2016

In the initial design stage, the geometry of systems needs to be optimized regarding its performance. However, performance analysis is very time-consuming. Therefore, optimization becomes difficult/impossible problems because we need to evaluate the system performance for alternative design cases. To overcome this problem, many researchers perform prediction of system performance using the approximation model. The response surface method (RSM) is typically used to predict the system performance in the various research fields, but it presents prediction errors for highly nonlinear systems. The major objective of this paper is to propose a proper prediction method for marine system problems. Case studies of marine systems (the substructure of a floating offshore wind turbine considering hydrodynamic performance and bulk carrier bottom stiffened panels considering structure performance) verify that the proposed method is applicable to performance prediction in marine systems.

• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1211-1224
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• 2023

Clouds cause many difficult problems in observing land surface phenomena using optical satellites, such as national land observation, disaster response, and change detection. In addition, the presence of clouds affects not only the image processing stage but also the final data quality, so it is necessary to identify and remove them. Therefore, in this study, we developed a new cloud detection technique that automatically performs a series of processes to search and extract the pixels closest to the spectral pattern of clouds in satellite images, select the optimal threshold, and produce a cloud mask based on the threshold. The cloud detection technique largely consists of three steps. In the first step, the process of converting the Digital Number (DN) unit image into top-of-atmosphere reflectance units was performed. In the second step, preprocessing such as Hue-Value-Saturation (HSV) transformation, triangle thresholding, and maximum likelihood classification was applied using the top of the atmosphere reflectance image, and the threshold for generating the initial cloud mask was determined for each image. In the third post-processing step, the noise included in the initial cloud mask created was removed and the cloud boundaries and interior were improved. As experimental data for cloud detection, CAS500-1 L2G images acquired in the Korean Peninsula from April to November, which show the diversity of spatial and seasonal distribution of clouds, were used. To verify the performance of the proposed method, the results generated by a simple thresholding method were compared. As a result of the experiment, compared to the existing method, the proposed method was able to detect clouds more accurately by considering the radiometric characteristics of each image through the preprocessing process. In addition, the results showed that the influence of bright objects (panel roofs, concrete roads, sand, etc.) other than cloud objects was minimized. The proposed method showed more than 30% improved results(F1-score) compared to the existing method but showed limitations in certain images containing snow.

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.91-97
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• 2003

The Propose of this paper is hierarchical detection method for the optic disc in fundus image. We detected the optic disc boundary by using the Prior information. It is based on the anatomical knowledge of fundus which are the vessel information. the image complexity. and etc. The whole method can be divided into three stages . First, we selected the region of interest(ROI) which included optic disc region. This is used to calculate location and size of the optic disc which are prior knowledge to simplify image preprocessing. And then. we divided the fundus image into numberous regions with watershed algorithm and detected intial boundary of the optic disc by reducing the number of the separated regions in ROI. Finally, we have searching the defective parts of boundary as a result of serious vessel interference in order to detect the accurate boundary of optic disc and we have removing and interpolating them.