고해상 광학센서의 스펙트럼 응답에 따른 영상융합 기법 비교분석

이하성 ( Ha Seong Lee ),오관영 ( Kwan Young Oh ),정형섭 ( Hyung Sup Jung ) 대한원격탐사학회 2014 大韓遠隔探査學會誌 Vol.30 No.2

본 연구는 서로 다른 센서 특성을 지닌 KOMPSAT-2, QuickBird 및 WorldView-2 고해상도 위성영상에 영상융합기법을 적용하여 그 결과를 비교평가 하는 것이다. 사용된 기법은 대표적인 CS 기반 융합기법인 GIHS, GIHSA, GS1 및 Adaptive IHS를 사용하였다. 영상융합 기법의 품질평가는 시각적 분석과 정량적 분석을 수행하였으며, 정량적 분석에는 SAM, Spectral ERGAS 및 Q4을 사용하였다. KOMPSAT-2 영상은 GHISA 기법의 경우 상대적으로 우수한 성능을 나타내는 반면, QuickBird와 WorldView-2영상은 GS1기법의 경우에 우수한 성능을 나타낸다. 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.

지진조기분석 시스템의 P파 탐지능력 향상을 위한 관측소별 잡음의 영향 분석

이하성(HaSeong Lee),조은영(EunYoung Jo) 대한지질학회 2016 대한지질학회 학술대회 Vol.2016 No.10

가격 기반의 에너지 저장장치 최적 운영 알고리즘 및 그 효과에 관한 연구

이하성(Ha-sung Lee),김다해(Dahae Kim),박경규(Kyung-gyu Park),곽동훈(Dong-hoon Kwak),김형수(Hyung soo Kim) 대한전기학회 2014 정보 및 제어 심포지엄 논문집 Vol.2014 No.10

에너지 저장장치는 생산된 전기를 저장하여 전력 수요가 필요할 때 방전하여 사용하는 시스템이다. 이러한 에너지 저장장치를 활용하여 한전 TOU 요금제를 기반으로한 에너지 저장장치의 최적 운영 알고리즘을 개발하고, 이 알고리즘을 적용하여 수용가에서 얻을 수 있는 전기요금 절감 효과에 대하여 분석하였다.

초정밀 비구면 렌즈 금형가공시스템 개발

백승엽,이하성,강동명,Baek, Seung-Yub,Lee, Ha-Sung,Kang, Dong-Myeong 한국금형공학회 2008 한국금형공학회지 Vol.2 No.1

As consumer in optics, electronics, aerospace and electronics industry grow, the demand for ultra precision aspherical surface lens increases higher. Precision turning with single-diamond tools has a long history of development for fabrication of optical quality surfaces since the advent of aerostatic rotary spindles and precise linear motion guide ways. To enhance the precision and productivity of ultra precision aspherical surface micro lens, the following specification of ultra precision grinding system is required: the highest rotational speed of the grinder is 100,000rpm and its turning accuracy is $0.1{\mu}m$, positioning accuracy is $0.1{\mu}m$. The development process of the grinding system for the ultra precision aspherical surface micro lens for optoelectronics industry is introduced. In the work reported in this paper, an intelligent grinding system for ultra precision aspherical surface machining was designed by considering the factors affecting the surface roughness and profiles accuracy. An aerostatic form was adopted to build the spindle of the workpiece and the spindle of grinder and ultra precision LM guide way was adopted in this system. And this paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. It results was that a form accuracy of $0.6{\mu}m$ P-V and a surface roughness of $0.006{\mu}m$ Rmax.

Can-Flange 성형에서 금형형상에 따른 소재 유동특성

고병두,이하성,Ko, Byung-Du,Lee, Ha-Sung 한국금형공학회 2012 한국금형공학회지 Vol.6 No.2

The paper deals with an analysis of an extrusion process with a divided material flow in a combined radial - backward extrusion. We have discussed the influences of tool geometry such as punch nose angle, relative gap height, die corner radius on material flow and surface expansion into can and flange region. To analyse the process, numerical simulations by the FEM and experiment by physical modeling using Al alloy as a model material have been performed. Based on the results, the influence of fixed parameters on the distribution of divided material flow and surface expansion are obtained.

금형부품의 품질향상을 위한 표면처리에 관한 연구

백승엽,이하성,강동명,Baek, Seung-Yub,Lee, Ha-Sung,Gang, Dong-Myung 한국금형공학회 2008 한국금형공학회지 Vol.2 No.5

Micro Electrochemical Machining(Micro ECM) has traditionally been used in highly specialized fields such as those of the aerospace and defense industries. It is now increasingly being applied in other industries where parts with difficult-to-cut material, complex geometry and tribology such as compute. hard disk drive(HDD) are required. Pulse Electrochemical Micro-machining provides an economical and effective method for machining high strength, high tension, heat-resistant materials into complex shapes such as turbine blades of titanium and aluminum alloys. Usually aluminum alloys are used bearings to hard disk drive in computer. In order to apply aluminum alloys to bearing used in hard disk drive, this paper presents the characteristics of Micro ECM for aluminum alloy.

굴삭기 Tank Cover 부품 뒤틀림 불량 저감에 대한 연구

전용준,이하성,김동언,허영무,Jeon, Yong-Jun,Lee, Ha-Sung,Kim, Dong-Earn,Heo, Young-Moo 한국금형공학회 2018 한국금형공학회지 Vol.12 No.1

With the recent strengthening of environmental regulations and the need for cost reduction, excavators, a type of construction equipment, are being miniaturized while components are being developed in consideration of stability. In the case of excavator press parts, mainly high-strength steel sheets are being used to enhance stability and reduce weight. However, in the case of high-strength materials, there is a need to research product forming methods to reduce Springback in defects arising in parts assembly due to Springback that result from the internal residual stress that occurs in press forming being released after product forming. Accordingly, regarding the tank cover, an excavator press-forming part, this study selected a method to reduce distortion through analysis of the Springback occurrence rate and Springback causes through a forming analysis. A forming analysis was conducted for the Springback of the tank cover. Deformations of 13.714 mm in the upper part and 6.244 mm in the inner part of the product occurred, while wrinkles occurred on the sides of the product due to uneven thickness. A forming analysis was conducted for the major shapes of the product to investigate the causes of Springback. Distortion deformation due to the bead in the center of the product was confirmed to be a large factor. A Springback reduction method of correcting uneven thickness in the product sides, a Springback reduction method of removing the bead, and a correction method of restriking after the final forming were used in a forming analysis to determine the degree of Springback reduction. For the forming method to correct uneven thickness in the sides, deformation was reduced by 12% in the upper side compared to the existing model, but deformation in the inner side increased by 1%. For the restriking forming method, deformation decreased by 25% in the upper side and 13% in the inner side. For the bead removal method, deformation decreased by 28% in the upper side and 13% in the inner side, the largest Springback correction results. This indicates that the bead has a large affect on Springback.

금형주조한 오스템퍼 회주철의 기계적 성질 및 파괴인성

이영상,이하성,강동명 ( Young Sang Yi,Ha Sung Lee,Dong Myeong Kang ) 한국주조공학회 1995 한국주조공학회지 Vol.15 No.3

N/A The mechanical properties and fracture toughness of permanent mold cast austempered gray cast iron(AGI) were compared to those of sand cast AGI. The iron was melted to eutectic composition in order to get better castability especially in permanent mold casting. Specimens prepared for tensile, impact and fracture toughness test were austenitized at 900℃ and austempered at 270℃ and 370℃ for 1hour. The strength, impact and fracture toughness of permanent mold cast AGI were found to be superior to those of sand cast AGI. The maximum value of 836㎫ in tensile strength, was obtained at the austempering temperature of 270℃. But ductility of AGI was not improved by permanent mold casting.

레이디얼 볼베어링의 내륜 끼워맞춤에 관한 유한요소해석

고병두,이하성,Ko, Byung-Du,Lee, Ha-Sung 한국금형공학회 2012 한국금형공학회지 Vol.6 No.1

The main goal of this paper is to establish an interference tolerance for determining optimal amount of clearance in the shaft-bearing system supported by radial ball bearings. The 2-D frictional contact model was employed for the FE analysis between the shaft and the inner raceway. Several examples were simulated using different material properties for the solid shaft. Efforts were focused on the deformation applied in the radial direction to select suitable bearings. The analysis results showed that the initial axial preload applied on the bearings plays a significant role to reduce bearing fatigue life. The proposed design parameters obtained by numerical simulations can approximately predict a rate of bearing life reduction as a function of shaft diameter ratio. This analysis can also be used to calculate the optimal initial radial clearance in order to obtain a shaft-bearing system design for high accuracy and long life.

금형 및 공정변수에 따른 층상복합재료의 압출성형 특성에 관한 연구

고병두,이하성,Ko, Byung-Du,Lee, Ha-Sung 한국금형공학회 2013 한국금형공학회지 Vol.7 No.1

This paper presents the plastic inhomogeneous deformation behavior of bimetal composite rods during the axisymmetric and steady-state extrusion process through a conical die. The rigid-plastic FE model considering frictional contact problem was used to analyze the co-extrusion process with material combinations of Cu/Al. Different cases of initial geometry shape for composite material were simulated under different conditions of co-extrusion process, which includes the interference and frictional conditions. The main design parameters influencing on deformation pattern are diameter ratio of the composite components and semi-die angle. Efforts are focused on the deformation patterns, velocity gradient, predicted forming load and the end distance through the various simulations. Simulation results indicate that there is an obvious difference of forming pattern with various diameter ratio and semi-die angle. The analysis in this paper is concentrated on the evaluation of the design parameters on the deformation pattern of composite rod.