• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.188-191
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• 2007

The Han River is divided into North and South Korea by NLL(Northern Limit Line) and its area has been blocked by CCL(Civil Control Line) since the Korean War in 1950. Satellite remote sensing, therefore, is uniquely suited to monitoring bar transformation in the region. In river with bar, the characteristics of its physical conditions have a close relationship with bar morphology. In this paper, a monitoring approach of bar transformation in the Han River Estuary is presented using RADARSAT/SAR images from 2000 to 2005 and spatial patterns of bar morphology are presented. it could be said that in the estuary vegetated area and natural levees are developed well, but bars are shifted after an event like a flood. It is also showed that suspended solids such as silt transported through the estuary could contribute highly to a sedimentation environment around Incheon.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.2 s.32
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• pp.39-43
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• 2005

In this study, we analyzed the accuracy of the conversion from DLT parameters to physical camera parameters and optimized the use of DLT model for non-metric cameras in photogrammetric tasks. Using the simulated data, we computed two sets of physical camera parameters from DLT parameters and Bundle adjustment for various cases. Comparing two results based on the RMSE values of check points, we optimized the arrangement of GCPs for DLT.

• 한국지형공간정보학회:학술대회논문집
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• 1994.04a
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• pp.14-30
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• 1994

Before GPS is practically used in Kores, we must fix a problem on the coordinate transfomation between WGS 84 and Korean geodetic system based on Bessel ellipsoid. On this article, I investigate various coordinate trans formation methods and review the researched results about the coordinate transformation which have been performed in Korea. With the inspection of which method is more applicable to Korea, I discuss about the future prospect and the fixing way for the problem of domestic coordinate transfomation.

• Journal of Sensor Science and Technology
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• v.11 no.4
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• pp.239-246
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• 2002

In this paper a new design of multi-layer perceptron(MLP) for camera calibration is proposed. Most existing techniques determine a transformation from 3D spatial points to their image points and camera parameters are tried to be estimated from the transformation. The technique proposed here, on the other hand, determines rays of sight uniquely from image points and parameters are estimated from the relationship using an MLP. By this approach projection and back-projection can be done more straightforwardly. Being based on a geometric model, a network design process becomes less ambiguous, which is a clear merit compared to other neural net based techniques. An MLP designed according to the technique proposed showed fast and stable learning in tests under various conditions.

• Annual Conference of KIPS
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• 2002.04a
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• pp.109-112
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• 2002

물리적 데이터베이스 설계기법은 최적의 질의처리 성능을 제공하기 위하여 데이터베이스의 액세스 구조를 결정하는 과정이다. 본 논문에서는 변환기법을 이용한 공간 액세스 구조의 물리적 데이터베이스의 설계를 위한 영역분할 전략을 제시한다. 변환기법을 이용한 공간 액세스 구조는 원공간(original space)에서의 공간 객체들을 공간의 차원을 두 배로 하는 변환공간(transformation space)내의 점 객체들로 변환하여 관리하는 방법이다. 먼저, 원공간에 주어지는 모든 공간 질의가 변환공간에서는 한가지 형태의 범위 질의로 변환되는 특징이 있음을 보인다. 그리고, 변환공간상에서 이 범의 질의가 위치하는 질의 영역의 모양과 데이터 페이지가 위치하는 페이지 영역의 모양 사이의 관련성을 이용하여 질의처리의 성능을 향상시킬 수 있는 영역분할 전략을 제안한다. 성능평가의 결과에 의하면, 주어진 질의 패턴에 따라 최적의 공간 액세스 구조를 구성할 수 있었으며, 이차원 원공간에 대한 사차원 변환 공간인 경우에 질의의 형태에 따라 질의처리의 성능이 다섯배 이상까지 향상되었다.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.8
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• pp.99-108
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• 1994

In this paper an image compression technique based on fractal theory using iterated contractive transformation is analysed and an improved image coder is suggested. Existing methods used the classifier proposed by Ramamurthi and Gersho which utilize the properties of neighboring pixels in the spatial domain. In this paper DCT-based classification is applied to 512$\times$512 images and PSNR improvement of 0.4~2.7 dB is obtained at lower bit rate over conventional algorithms. In addition the effect of varying the domain block size and quantization step size of the luminance shift parameter on the compression ratio and the image quality is compared and analysed.

• The Journal of Information Technology and Database
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• v.5 no.1
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• pp.109-119
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• 1998

Users want to browse various groups of nested attribute values of an object. On the other hand, in case of the presentation of a multimedia object, the form-based presentation is superior to the graph-based presentation. Therefore we propose a form-based presentation transformation scheme that allows users to reorganize the presentation layout to fit the limited screen and to show the values of all the needed attributes. For the representation of the presentation scenario of an object a presentation information class and the presentation transformation operations are defined. We show how these operations transform the default presentation into the wanted presentation by navigating through a multimedia object with the COMIB (COMposite Icon Browser).

• Current Optics and Photonics
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• v.5 no.2
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• pp.191-197
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• 2021

The anomalous propagation characteristics of a single Airy beam in nonlocal nonlinear medium are investigated by utilizing the split-step Fourier-transform method. We show that besides the normal straight propagation trajectory, the breathing solitons formed by the interaction between Airy beam and nonlocal nonlinear medium can propagate along the sinusoidal trajectory, and the anomalous trajectory can be modulated arbitrarily by altering the initial amplitude and the nonlocal nonlinear coefficient. In addition, the initial amplitude and the nonlocal nonlinear coefficient can have inverse impacts on the formation and transformation of the equilibrium state of spatial solitons, when the two parameters are larger than certain values. Therefore, the reversible transformation of the evolution dynamics of two soliton states can be realized by adjusting those two parameters properly. Finally, it is shown that the propagation properties of the solitons formed by the interaction between Airy beam and nonlocal nonlinear medium can be controlled arbitrarily, by adjusting the distribution factor and nonlocal coefficient.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.30-41
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• 1993

Developed in this paper is a feature based modeling system for the design of welded plat construction(WPC) which is composed of flat or bended plates represented as reference plane with a constant thickness. First, the necessity and the characteristics of the modeing system for WPC as compared with the assembly of mechanical parts are investigated. Secondly, feature library for the assembly of WPC is shown which contains several types of features like joint feature, groove feature, material feature, and precision feature. Thirdly, the assembly procedures are presented which mainly consist of both the assembly transformation and the correct assembly checking. Fourthly, weld lines of the assembled WPC are defined so that those can be used in the process planning or the manufacturing stage. Finally, a prototype by a geometric modeling software Pro/Engineer, a graphic software GL(Graphic Library), and C language on a CAD workstation IRIS.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.49-54
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• 2008

Recently, with the development of wireless communications and GIS, interest about mobile computing is rising. In this case, the GIS needs to be placed in a constricted environment than the environment of server computing. For this reason large amounts of spatial data must be compressed into the mobile device. The compression technique of the spatial data is difficult and must be processed in the correct order because the size of the data is unpredictable. Therefore, in this paper, the cell-based compression technique of the spatial data for mobile GIS is presented. This paper includes the process of transformation of spatial data from a certain server to a mobile device by cell-based compression technique. In this paper, the cell-based compression technique of the spatial data has been proven practically efficient.