• Korean Journal of Agricultural and Forest Meteorology
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• v.26 no.2
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• pp.89-102
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• 2024

Land Surface Phenology (LSP) plays a crucial role in understanding vegetation dynamics. The near-infrared reflectance of vegetation (NIRv) has been increasingly adopted in LSP studies, being recognized as a robust proxy for gross primary production (GPP). However, NIR v is sensitive to the terrain effects in mountainous areas due to artifacts in NIR reflectance cannot be canceled out. Because of this, estimating phenological metrics in mountainous regions have a substantial uncertainty, especially in the end of season (EOS). The topographically corrected NIRv (TCNIRv) employs the path length correction (PLC) method, which was deduced from the simplification of the radiative transfer equation, to alleviate limitations related to the terrain effects. TCNIRv has been demonstrated to estimate phenology metrics more accurately than NIRv, especially exhibiting improved estimation of EOS. As the topographic effect is significantly influenced by terrain properties such as slope and aspect, our study compared phenology metrics estimations between south-facing slopes (SFS) and north-facing slopes (NFS) using NIRv and TCNIRv in two distinct mountainous regions: Gwangneung Forest (GF) and Odaesan National Park (ONP), representing relatively flat and rugged areas, respectively. The results indicated that TCNIR v-derived EOS at NFS occurred later than that at SFS for both study sites (GF : DOY 266.8/268.3 at SFS/NFS; ONP : DOY 262.0/264.8 at SFS/NFS), in contrast to the results obtained with NIRv (GF : DOY 270.3/265.5 at SFS/NFS; ONP : DOY 265.0/261.8 at SFS/NFS). Additionally, the gap between SFS and NFS diminished after topographic correction (GF : DOY 270.3/265.5 at SFS/NFS; ONP : DOY 265.0/261.8 at SFS/NFS). We conclude that TCNIRv exhibits discrepancy with NIR v in EOS detection considering slope orientation. Our findings underscore the necessity of topographic correction in estimating photosynthetic phenology, considering slope orientation, especially in diverse terrain conditions.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.92-97
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• 2002

A real-time OTF (optical transfer function) measuring system with on- and off-axis nodal slide bench type for the camera lens is fabricated and evaluated. It consists of a nodal slide bench including a T-bar for the OTF measurement of an off-axis object, two dimensional CCD (charge coupled device) with pixel of 9.9${\mu}{\textrm}{m}$$\times$9.6${\mu}{\textrm}{m}$ for real-time OTF measurment, and a collimating lens of focal length of 300 mm for the optimization of this system. The OTF system is corrected by using the OTF of a SIRA lens of fnumber of F/8 and focal length 50 mm. In order to confirm the reliability of the OTF system, two MTFs (modulus transfer functions) of CCTV & VIDEO lens (JAPAN, AVENIR-SE 2514) of focal length of 25mm and field of view 10.6$^{\circ}$are measured by the camera bench type OTF system of reference OTF system and the nodal slide bench type OTF system and compared with each other. As a result, these two values are agree well with each other within 4% from 0 1p/mm to 100 1p/mm.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.11a
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• pp.49-52
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• 2007

전략 게임은 여러 종류의 유닛 (Unit)이 존재한다. 각각의 유닛은 특정 유닛에 대해 강한 면모를 보이기도 하고, 또 다른 종류의 유닛에게는 약한 면모를 가지고 있다. 이를 유닛간의 상성이라고 한다. 상성은 전략적 선택을 하는데 기반이 되고, 심리전을 유발하여 보다 게임에 몰입할 수 있게 해준다. 게임 인공지능이 상성을 고려하도록 하기 위해 각각의 유닛 간에 수치화된 상성 정보가 필요하다. 그리고 생성된 수치 자료를 토대로 유닛의 행동방법을 결정할 인공 지능도 필요하게 된다. 다음 행동 및 이동을 위해 주로 사용되는 방법은 영향력 분포도(influence map)이다. 영향력 분포도는 자신과 상대방의 세력을 수치적으로 파악하는 것이다. 하지만 일반적인 형태의 영향력 분포도로는 각 유닛간의 상성을 표현하기 힘들다. 따라서 본 논문에서는 영향력 분포도를 상성에 맞게 보정할 수 있는 방법을 제시하여 인공지능이 지능적인 행동을 하도록 돕는 방법을 제안한다. 이를 길 찾기 문제에 적용하여 전략적 이동경로를 선택하는 방법을 제시하였다.

• Journal of Korea Spatial Information System Society
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• v.11 no.1
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• pp.183-188
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• 2009

In this paper, we preset a method for the development of u-GIS outdoor augmented reality(AR) system. The proposed system is consist of three parts. First, sensor acquisition and calibration for AR, Second, camera and sensor based tracking for AR, Third, integration of sensor information and 3D models. We combine spatial information of real and virtual spaces through u-GIS AR system.

• Annual Conference of KIPS
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• 2003.11a
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• pp.505-508
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• 2003

디지털 영상 자천가 대중화됨에 따라 방대한 양의 자료를 효과적으로 이용 및 검색하기 하기 위해 영상 데이터의 색인과정이 필수적이다. 뉴스 데이터에서 자막 프레임은 뉴스의 내용을 한 눈에 파악할 수 있는 중요한 정보이다. 따라서 본 논문에서는 뉴스 데이터에서 색인과정을 위해 우선 자막 프레임을 검출하는 기법을 제안하고자 한다. 자막이 있는 프레임을 검출하기 위해 가변길이 프레임 생략법을 이용하여 키프레임을 검출한다. 영상보정을 위한 전처리 작업으로 BC(Brightness & Contrast) 필터기법을 제안하고 자막영역을 대상으로 IT(Invers & Threshold) 기법을 적용하여 자막프레임을 검출하는 방법을 제안한다.

• The Journal of the Acoustical Society of Korea
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• v.18 no.2
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• pp.25-31
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• 1999

An array aperture synthesis technique is proposed. The proposed method does not require the condition that the overlapped hydrophones have the identical position in space to estimate the phase correction factors. while the existing ETAM algorithm does. Therefore the proposed method increases the available data applied to extend the effective aperture length of the towed array. From the numerical experiments, the proposed method can reduce the mean square error in estimating the direction of a target signal.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.614-619
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• 1997

The hydraulic pressure pulsation has on the effected on the acoustic nosie and control performance of the hydraulic-servo system. The Helmholtz attenuator introduction on the hydraulic line is an efficient device to reduce the hydraulic pulsation. The salient feature of causing hydraulic pulsation and the frequency characteristics of Helmholtz attenuator are studied. The hydraulic filter design parameters such as the locating position, connecting orifice area and accumulator volume are mathematically analyzed. The instrumental works are carried out with the remarkable reduction of the hydraulic pressure pulsation magnitude and the acoustic noise level.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.354-354
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• 2008

Recently, due to the tremendous growth of media technology, demands of the aspheric glass lens which is a high-performance and miniaturized is gradually increasing. Generally, the aspheric glass lens is manufactured by GMP(Grass Molding Press) method using WC(tungsten carbide) mold core. In this study, the thermal deformation which occurs in the cooling step of GMP was considered, and it was compensated the form of mold core. The lens which was molded by compensated mold core was satisfied that can be applied to the actual specifications.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.307-309
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• 1993

Robot's kinematic equation is not perfect. In this paper, a method for reducing the positioning error which comes from the imperfect robot kinematics is introduced. This method compensates the parameter of the kinematic equation using real positioning error. And the trajectories using these compensated parameterare compared with uncompensated ones.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.351-355
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• 2003

Recently, the Rapid Prototyping System makes used of changing file format. The most problem is produced by this process. It is influenced by the precision of shape manufacturing. And It is most influenced by shrinkage rate within many elements influence the precision of 3D shape manufacturing. In result, the length strain in each axis cause at STL file transforming. It will compensate for utilizing the shrinkage rate.