• 전기학회논문지
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• 제62권9호
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• pp.1270-1275
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• 2013

A lot of research about camera calibration and lens distortion for wide-angle lens has been made. Especially, calibration for fish-eye lens which has 180 degree FOV(field of view) or above is more tricky, so existing research employed a huge calibration pattern or even 3D pattern. And it is important that calibration parameters (such as distortion coefficients) are suitably initialized to get accurate calibration results. It can be achieved by using manufacturer information or lease-square method for relatively narrow FOV(135, 150 degree) lens. In this paper, without any previous manufacturer information, camera calibration and barrel undistortion for fish-eye lens with over 180 degree FOV are achieved by only using one calibration pattern image. We applied QR decomposition for initialization and Regularization for optimization. With the result of experiment, we verified that our algorithm can achieve camera calibration and image undistortion successfully.

• 한국응용과학기술학회지
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• 제26권2호
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• pp.205-212
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• 2009

Solution copolymerization of Styrene(St.) with 2-Hydroxypropylacrylate(2-HPA) was carried out with Benzoylperoxide(BPO) as an initiator in toluene at $80^{\circ}C$ in a batch reactor. Reaction volume and reaction time were 0.3 liters, 8 hours respectively. The time to reach steady state was about the six time. The monomer reactivity ratios, $r_1$(St.) and $r_2$(2-HPA) were determined by both the Kelen-Tudos method and the Fineman-Ross method ; $r_1$(St.)=0.376(0.330), $r_2$(2-HPA)=0.408(0.778). The activation energy of thermal decomposition was in the range of $33{\sim}55kcal/mol$.

• 한국경영과학회지
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• 제11권1호
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• pp.24-35
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• 1986

We investigate various methods of the Benders decoposition algorithm in its application to the simple plant location problem. We developed six variants. The master problem may be relaxed as an LP problem up to an appropriate point in time, or need not be solved to the optimality before a cut is added. Furthermore, since the subproblem is highly degenerated, we can generate more than one cuts at a time. The efficiency of the methods are examined using a sample problem. The result showed that the adding two-cut method was superior to the standard method. The LP relaxation and the non-optimization of the master program greatly improved the efficiency. Applying the LP relaxation method, we were able to reduce the computing time by two thirds of the time required by the standard method.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권3호
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• pp.146-152
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• 2011

Thermal stability of $Ge_2Sb_2Te_5$ (GST) and $SiO_2$ doped GST (SGST) films for phase change random access memory applications was investigated by observing the change of surface roughness, layer density and composition of both films after isothermal annealing. After both GST and SGST films were annealed at $325^{\circ}C$ for 20 min, root mean square (RMS) surface roughness of GST was increased from 1.9 to 35.9 nm but that of SGST was almost unchanged. Layer density of GST also steeply decreased from 72.48 to 68.98 $g/cm^2$ and composition was largely varied from Ge : Sb : Te = 22.3 : 22.1 : 55.6 to 24.2 : 22.7 : 53.1, while those of SGST were almost unchanged. It was confirmed that the addition of a small amount of $SiO_2$ into GST film restricted the deterioration of physical and chemical properties of GST film, resulting in the better thermal stability after isothermal annealing.

• 한국학교수학회논문집
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• 제8권3호
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• pp.315-325
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• 2005

학교교육에서 수학은 분명한 하나의 독립된 교과이다. 그러나 수학의 기능과 역할은 다른 교과와 결합할 때 보다 뚜렷해진다. 예를 들어, 과학문제를 해결하기 위해서 수학을 사용하였다면 수학의 가치뿐만이 아니라 수학의 과학에 대한 역할을 어느 정도 이해할 수 있을 것이다. 이와 같이 수학의 기능을 이해하려면 수학의 응용문제를 다루면서 공부하는 것이 일반적이다. 하지만 응용문제에서 수학은 하나의 보조적 역할이므로 학생들은 수학의 기능을 간과하기 쉽다. 그러므로 응용문제 또는 통합교과적인 문제에서 수학을 정확히 이해하고, 활용능력을 향상시키기 위해서는 수학적 영역을 따로 분리해서 이해시키도록 하는 편이 좋다. 본 논문에서는 이와 관련한 하나의 교수방법을 제시한다.