• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.543-547
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• 2002

In this paper, we introduce a more improved camera modeling method for linear pushbroom images than the method proposed by Orun and Natarajan(ON). ON model shows an accuracy of within 1 pixel if more than 10 ground control points(GCPs) are provided. In general, there is high correlation between platform position and attitude parameters but ON model ignores attitude variation in order to overcome such correlation. We propose a new method that obtains an optimal solution set of parameters without ignoring the attitude variation. We first assume that attitude parameters are constant and estimate platform position's. Then we estimate platform attitude parameters using the values of estimated position parameters. As a result, we can set up an accurate camera model for a linear pushbroom satellite scene. In particular, we can apply the camera model to its surrounding scenes because our model provide sufficient information on satellite's position and attitude not only for a single scene but also for a whole imaging segment. We tested on two images: one with a pixel size 6.6m$\times$6.6m acquired from EOC(Electro Optical Camera), and the other with a pixel size 10m$\times$l0m acquired from SPOT. Our camera model procedures were applied to the images and gave satisfying results. We had obtained the root mean square errors of 0.5 pixel and 0.3 pixel with 25 GCPs and 23 GCPs, respectively.

• 한국통신학회논문지
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• 제19권2호
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• pp.331-337
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• 1994

저항띠의 양끝에서 0( /square)으로 변하는 저항율을 가진 저항띠의 적자구조에 비스듬히 입사하는 E분극 평면파에 의한 전자파 산람눙제를 과수영역에서 모멘트 법을 이용하여 해석하였따. 이때 저항띠에 유도되는 전류일도는 2종 Chebyshev 다항식의 급수로 전개하였다 전개계수들은 과수영역에서 수치계산하였고, 본 논문에서의 변하는 저항율을 갖는 경우와 기존의 균일 저항율을 갖는 경우에 대해 기하광학적 반사계수의 수치계산 결과를 비교하였다. 그리고 기하광학적 반사계수의 크기에서 급변점들이 위치는 입사각과 스트립 주기를 변화시킴으로써 이동시킬 수 있었다. 이러한 급변점들은 전파모드와 감쇠모드 사이서 고차모드가 천이될 때 발생함을 알 수 있었다.

• 정보처리학회논문지B
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• 제9B권3호
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• pp.369-374
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• 2002

본 논문에서는 명암도 변화값과 기하학적 패턴벡터를 이용하여 실시간으로 차량번호판을 추출하고 인식하는 알고리즘을 제안하였다. 일반적으로 차량영상에서는 번호판 영역에서 문자와 배경이 뚜렷하게 구별되고, 일정한 명암도 변화를 가지면서 번호판 이외의 다른 영역보다 밀집도가 높은 특성이 있다. 따라서 본 논문에서는 이러한 성질을 이용하여 먼저 명암도 변화값을 사용하여 번호판을 추출하도록 하였으며 영상 입력과정에서 외부 환경에 따라 차량영상이 어둡거나 밝게 입력될 경우에도 동일한 추출 성능을 얻기 위하여 밝기 보정 과정을 수행하였다. 또한 추출된 번호판 영역으로부터 입력 문자의 크기, 이동 및 회전에 무관한 특성 추출을 위해 번호판 영역에서 잡음 제거와 세선화를 적용하여 전처리후 제안한 기하학적 패턴벡터를 이용하여 차량번호를 인식하도록 하였다. 제안한 방법들을 적용한 결과 기존의 원형 패턴벡터 보다 계산 속도가 빠르며, 차량번호판의 크기와 잡음에 무관하며, 불규칙한 조명 상태에서도 정확한 차량 번호를 인식할 수 있었다.

• 대한원격탐사학회지
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• 제26권6호
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• pp.653-664
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• 2010

The land surface reflectance is a key parameter influencing the climate near the surface. Therefore, it must be determined with sufficient accuracy for climate change research. In particular, the characteristics of the bidirectional reflectance distribution function (BRDF) when using earth observation system (EOS) are important for normalizing the reflected solar radiation from the earth's surface. Also, wide swath satellites like SPOT/VGT (VEGETATION) permit sufficient angular sampling, but high resolution satellites are impossible to obtain sufficient angular sampling over a pixel during short period because of their narrow swath scanning. This gives a difficulty to BRDF model based reflectance normalization of high resolution satellites. The principal objective of the study is to add BRDF modeling of high resolution satellites and to supply insufficient angular sampling through identifying BRDF components from SPOT/VGT. This study is performed as the preliminary data for apply to high-resolution satellite. The study provides surface parameters by eliminating BRD effect when calculated biophysical index of plant by BRDF model. We use semi-empirical BRDF model to identify the BRD components. This study uses SPOT/VGT satellite data acquired in the S1 (daily) data. Modeled reflectance values show a good agreement with measured reflectance values from SPOT satellite. This study analyzes BRD effect components by using the NDVI(Normalized Difference Vegetation Index) and the angle components such as solar zenith angle, satellite zenith angle and relative azimuth angle. Geometric scattering kernel mainly depends on the azimuth angle variation and volumetric scattering kernel is less dependent on the azimuth angle variation. Also, forest from land cover shows the wider distribution of value than cropland, overall tendency is similar. Forest shows relatively larger value of geometric term ($K_1{\cdot}f_1$) than cropland, When performed comparison between cropland and forest. Angle and NDVI value are closely related.

• 대한기계학회논문집A
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• 제33권9호
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• pp.903-912
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• 2009

This study is focused on simulation-based dimensional tolerance optimization process (DTOP) to minimize vehicle pulls by reduction of dimensional variation in front suspension system. In previous studies, the effect of tires and wheel alignment sensitivity have mainly been investigated to eliminate vehicle pulls in nominal design condition without allocating optimal tolerance level for selected components, among various factors regarding vehicle pulls such as vehicle design parameters, vehicle weight balance, tires, and environmental factors. Unfortunately, there are wide variations in the real vehicle, and these have impacted actual vehicle pulls, especially wheel alignment effects from suspension geometry variation has not been considered in the previous studies. In the tolerance design of suspension, tolerance variables with the uncertainty such as parts dimensional variation, assembly process, datum position and direction, and assembly tool tolerance has a great influence on the variation of the suspension dimensional performances. This study introduces total vehicle pull prediction model in considering major key factors for vehicle pull sensitivity. The Monte Carlo-based tolerance analysis model using Taguchi robust method is developed to optimize dimensional tolerance parameters, satisfying on the target variation level.

• 대한전자공학회논문지SP
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• 제46권1호
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• pp.56-62
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• 2009

산업용 강판튜브 CR영상의 잡음특성과 기하학적 구조에 관한 해석적 접근을 시도한다. 산업현장에서 방사선 측정실험으로 직접 취득한 방사선영상을 방사선강도에 따라 30(개) 이상의 샘플을 수집하였다. 이들 각 영상은 배경부, 두께부 및 튜브내부의 세 영역으로 구성되었는바, 그 가운데 튜브내부영역을 분석 대상으로 삼았다. 통계적이고 함수적인 방법론에 의해 잡음특성을 포함한 기하학적 구조를 분석한다. 영상을 구성하는 화소라인별로 또는 공간적으로 분석을 수행하여 강판튜브의 기하학적 원형 형태가 방사선영상화 과정을 거치면서 일어나는 변형과 잡음속성 변화의 두 가지 특성을 규명한다. 분석시 부합함수와 그 오차를 기하학적 변형의 판별인자로, 표준편차, 평균 및 SN비를 잡음특성 판별인자로 설정하고 방사선투과정도의 영상에서의 실현인 회색도 변화에 따른 이들 인자들의 변화를 고찰하였다. 분석결과, 본래의 원형 구조가 방사선투과 강도에 따라 타원형에서 저반경 원형 그리고 고반경원형의 점차적인 구조 변형을 일으킨다는 사실을 밝혔고, 잡음의 편차가 투과강도에 반비례함을 규명하였다.

• Interaction and multiscale mechanics
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• 제3권4호
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• pp.309-320
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• 2010

With taking the geometric nonlinearity of bridge structure into account, a framework is presented for predicting the dynamic responses of a long-span suspension bridge subjected to running train and turbulent wind. The nonlinear dynamic equations of the coupled train-bridge-wind system are established, and solved with the Newmark numerical integration and direct interactive method. The corresponding linear and nonlinear processes for solving the system equation are described, and the corresponding computer codes are written. The proposed framework is then applied to a schemed long-span suspension bridge with the main span of 1120 m. The whole histories of the train passing through the bridge under turbulent wind are simulated, and the dynamic responses of the bridge are obtained. The results demonstrate that the geometric nonlinearity does not influence the variation tendency of the bridge displacement histories, but the maximum responses will be changed obviously; the lateral displacement of bridge are more sensitive to the wind than the vertical ones; compared with wind velocity, train speed affects the vertical maximum responses a little more clearly.

• 한국환경보건학회지
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• 제26권2호
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• pp.108-115
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• 2000

The mass fraction of PM10 had a bimodal distribution in the middle of between 2.1 ${\mu}{\textrm}{m}$, and the average mass fraction of particles less than 2.1~3.1 ${\mu}{\textrm}{m}$ was 54.1% for Pb and 890.8 ng/㎥ for Fe, respectively. For the concentration of PM10 and metallic elements by seasonal variation, PM10 showed bimodal distribution, while metallic elements showed different distributions by their sources. The ratios of fine particles to total mass were 0.45 for PM10, 0.41 for Cr, and 0.20 for Fe, 0.57 for Zn, 0.68 for Cd and 0.63 for Pb, respectively. That facts indicated that PM10, Zn, Cd, Cr and Pb were from anthropogenic sources, and Fe was from natural source. The geometric means and geometric standard deviations by seasonal variations were 3.6 ${\mu}{\textrm}{m}$ , 2.31 ${\mu}{\textrm}{m}$ in winter, 3.0 ${\mu}{\textrm}{m}$ , 2.49 ${\mu}{\textrm}{m}$ in spring, 2.7 ${\mu}{\textrm}{m}$ , 2.03 ${\mu}{\textrm}{m}$ in summer respectively. And, total efficiency of cascade impactor by seasonal variations were 49.6% in winter, 45.9% in spring and 44.5% in summer.

• 한국수학사학회지
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• 제27권4호
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• pp.271-283
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• 2014

This study takes a look at Polya's analysis on Archimedes' "The Method" from a math-historical perspective. We, based on the elaboration of Polya's analysis, investigate the analytic geometric characteristics of Archimedes' "The Method" and discuss the way of using the characteristics in education of school calculus. So this study brings up the educational need of approach of teaching the definite integral by clearly disclosing the transition from length, area, volume etc into the length as an area function under a curve. And this study suggests the approach of teaching both merit and deficiency of the indivisibles method, and the educational necessity of making students realizing that the strength of analytic geometry lies in overcoming deficiency of the indivisibles method by dealing with the relation of variation and rate of change by means of algebraic expression and graph.

• 디지털콘텐츠학회 논문지
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• 제9권1호
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• pp.109-116
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• 2008

정칙적인 곡선이나 곡면에 대해서만 적용되고 있는 전통적인 개념의 미적분을 복잡하고 비 정칙적인 대상에도 적용할 수 있는 방법들이 다양하게 시도되고 있다. 이에 본 논문에서는 비 정수 차수의 도함수를 적분의 한 형태로 변환하여 표현하는 방법을 알아보고 이를 효과적으로 구현함으로 실제적인 응용을 할 수 있게 하였다.