• 제목/요약/키워드: Scattering Center

검색결과 544건 처리시간 0.045초

파수영역에서 모멘트 방법을 이용한 새로운 역산란 방법, II : 수치계산 (A New Inverse Scattering Technique Using the Moment Method in the Spectral Domain, II: Numerical Simulation)

  • 이재민;김세윤;나정웅
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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    • pp.442-445
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    • 1988
  • In this paper, the reconstruction of complex permittivity distribution on a rectangular cross section of inhomogeneous dielectric cylinders is performed by employing the spectral inverse scattering scheme. Numerical simulations provide the superresolution to the permittivity profiles nearly regardless of the measurement locations of the scattered field and the permittivity distributions on the cross section.

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Synthesis and Characterization of Poly(alkyl $\alpha$, L-glutamate-co-ethylene oxide)

  • Kim, Gunwoo;Kim, Jin-Yeol;Daewon Sohn;Lee, Youngil
    • Macromolecular Research
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    • 제10권1호
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    • pp.49-52
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    • 2002
  • Rod-coil amphiphilic block copolymers, PALG-PEOs, poly(alkyl $\alpha$, L-glutamate-co-ethylene oxide)s, were successfully synthesized in three steps: 1) esterification of L-glutamic acid, 2) synthesis of ${\gamma}$-alkyl L-gultamate N-carboxyanhydride, and 3) polymerization of NCA monomers. These molecules form polymeric micelles with the hydrophobic core and hydrophilic corona in aqueous solution, which were characterized by light scattering and static fluorescence measurement.

Modified Finite Volume Time Domain Method for Efficient Prediction of Radar Cross Section at High Frequencies

  • Chatterjee, Avijit;Myong, Rho-Shin
    • Journal of electromagnetic engineering and science
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    • 제8권3호
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    • pp.100-109
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    • 2008
  • The finite volume time domain(FVTD) technique faces serious limitations in simulating electromagnetic scattering at high frequencies due to requirements related to discretization. A modified FVTD method is proposed for electrically large, perfectly conducting scatterers by partially incorporating a time-domain physical optics(PO) approximation for the surface current. Dominant specular returns in the modified FVTD method are modeled using a PO approximation of the surface current allowing for a much coarser discretization at high electrical sizes compared to the original FVTD scheme. This coarse discretization can be based on the minimum surface resolution required for a satisfactory numerical evaluation of the PO integral for the scattered far-field. Non-uniform discretization and spatial accuracy can also be used in the context of the modified FVTD method. The modified FVTD method is aimed at simulating electromagnetic scattering from geometries containing long smooth illuminated sections with respect to the incident wave. The computational efficiency of the modified FVTD method for higher electrical sizes are shown by solving two-dimensional test cases involving electromagnetic scattering from a circular cylinder and a symmetric airfoil.

산란점 정보를 이용한 표적 SAR 영상 간 유사도 평가기법 (Method for Similarity Assessment Between Target SAR Images Using Scattering Center Information)

  • 박지훈;임호
    • 한국군사과학기술학회지
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    • 제22권6호
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    • pp.735-744
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    • 2019
  • One of the key factors for recognition performance in the automatic target recognition for synthetic aperture radar imagery(SAR-ATR) system is reliability of the SAR target database. To achieve optimal performance, the database should be constructed using the images obtained under the same operating condition as the SAR sensor. However, it is impractical to have the extensive set of real-world SAR images, and thus those from the electro magnetic prediction tool with 3-D CAD models are suggested as an alternative where their reliability can be always questionable. In this paper, a method for similarity assessment between target SAR images is presented inspired by the fact that a target SAR image is mainly characterized by the features of scattering centers. The method is demonstrated using a variety of examples and quantitatively measures the similarity related to reliability. Its assessment performance is further compared with that of the existing metric, structural similarity(SSIM).

Development of radar cross section analysis system of naval ships

  • Kim, Kook-Hyun;Kim, Jin-Hyeong;Choi, Tae-Muk;Cho, Dae-Seung
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제4권1호
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    • pp.20-32
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    • 2012
  • A software system for a complex object scattering analysis, named SYSCOS, has been developed for a systematic radar cross section (RCS) analysis and reduction design. The system is based on the high frequency analysis methods of physical optics, geometrical optics, and physical theory of diffraction, which are suitable for RCS analysis of electromagnetically large and complex targets as like naval ships. In addition, a direct scattering center analysis function has been included, which gives relatively simple and intuitive way to discriminate problem areas in design stage when comparing with conventional image-based approaches. In this paper, the theoretical background and the organization of the SYSCOS system are presented. To verify its accuracy and to demonstrate its applicability, numerical analyses for a square plate, a sphere and a cylinder, a weapon system and a virtual naval ship have been carried out, of which results have been compared with analytic solutions and those obtained by the other existing software.