• Title/Summary/Keyword: Gradient Transition Vector

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A study on the Precision Pattern Measurement Based on Gradient Transition Vector (그라디언트 변이 벡터 기반 패턴 측정에 관한 연구)

  • Kim, Gyung Bum
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.3
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    • pp.45-50
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    • 2021
  • The adjustment of lens magnification can make the degree of precision in pattern measurement be improved, but several problems such as high cost, smaller field of view and stage error accumulation are followed. In this paper, a method for precisely measuring patterns is proposed based on gradient transition vector, in order to solve these problems. The performance of our method is evaluated using pattern images with several directions. Also, it is compared with previous methods based on edge and gray-level moment. It is judged that the proposed method outperforms consistent pattern width results, and so could be applied to automation processes for measurement and inspection of precise and complexed patterns in IT, BT industry products.

Sizes and Structures of Micelles of Cationic Octadecyl Trimethyl Ammonium Chloride and Anionic Ammonium Dodecyl Sulfate Surfactants in Aqueous Solutions

  • Kim, Hong-Un;Lim, Kyung-Hee
    • Bulletin of the Korean Chemical Society
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    • v.25 no.3
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    • pp.382-388
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    • 2004
  • The sizes and structures of micelles formed in aqueous solutions of cationic octadecyl trimethyl ammonium chloride (OTAC) and anionic ammonium dodecyl sulfate (ADS) surfactants were investigated using smallangle neutron scattering (SANS), self-diffusion coefficients by pulsed-gradient spin-echo (PGSE) NMR, and dynamic light scattering (DLS) methods. SANS and DLS data indicate that their structures are spherical at concentrations as high as 300 mM. As the total surfactant concentration increases, the peaks of SANS spectra shift to higher scattering vector and become sharper, indicating that the intermicellar distance decreases and its distribution becomes narrower. This is due to more compact packing of surfactant molecules at high concentrations. The intermicellar distance of around 100 ${\AA}$ above 200 mM corresponds approximately to the diameter of one micelle. The sizes of spherical micelles are 61 ${\AA}$ and 41 ${\AA}$ for 9 mM OTAC and 10 mM ADS, respectively. Also the self-diffusion coefficients by PGSE-NMR yield the apparent sizes 96 ${\AA}$ and 31 ${\AA}$ for micelles of 1 mM OTAC and 10 mM ADS, respectively. For ADS solutions of high concentrations (100-300 mM), DLS data show that the micelle size remains constant at $25{\pm}2{\AA}$. This indicates that the transition in micellar shape does not take place up to 300 mM, which is consistent with the SANS results.

The Cubically Filtered Gradient Algorithm and Structure for Efficient Adaptive Filter Design (효율적인 적응 필터 설계를 위한 제 3 차 필터화 경사도 알고리즘과 구조)

  • 김해정;이두수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.11
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    • pp.1714-1725
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    • 1993
  • This paper analyzes the properties of such algorithm that corresponds to the nonlinear adaptive algorithm with additional update terms, parameterized by the scalar factors a1, a2, a3 and Presents its structure. The analysis of convergence leads to eigenvalues of the transition matrix for the mean weight vector. Regions in which the algorithm becomes stable are demonstrated. The time constant is derived and the computational complexities of MLMS algorithms are compared with those of the conventional LMS, sign, LFG, and QFG algorithms. The properties of convergence in the mean square are analyzed and the expressions of the mean square recursion and the excess mean square error are derived. The necessary condition for the CFG algorithm to be stable is attained. In the computer simulation applied to the system identification the CFG algorithm has the more computation complexities but the faster convergence speed than LMS, LFG and QFG algorithms.

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Analysis of Quadratically Filtered Gradient Algorithm with Application to Channel Equalization (채널 등화기에 응용한 제2차 필터화 경사도 알고리즘의 해석)

  • 김해정;이두수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.1
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    • pp.131-142
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    • 1994
  • This paper analyzes the properties of such algorithm that corresponds to the nonlinear adaptive algorithm with additional update terns, parameterized by the scalar factors ${\alpha}1,\;and\;{\alpha}2$. The analysis of concergence leads to eigenvalues of the transition matrix for the mean filter coefficient vector. Regions in which the algorithm becomes stable are demonstrated. The time constant is derived and the computational complexity of the QFG algorithm is compared with those of the conventional LMS. sign, and LFG algorithm. The properties of convergence in the mean square error is derived and the neccessary condition for the CFG algorithm to be stable is attaned. In the computer simulation a channel equalization is utilized to demonstrate the performance feature of the QFG algorithm. The QFG algorithm has the more computational complexities but the faster convergence speed than LMS and LFG algorithm. Since the QFG algorithm has smoother convergence, it may be useful in case where error bursting is a problem.

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