• Title/Summary/Keyword: Dai

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A Bed Schematized Two-dimensional Sediment Transport Model

  • Jin, Jae-Youll;Kim, Hyo-Seob;Lee, Kwang-Soo;Yum, Ki-Dai
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 1992.08a
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    • pp.158-165
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    • 1992
  • Bottom sediments, in various types of sediment transport models, have been usually assumed to be horizontally and/or vertically homogeneous. The assumption may be appropriate in well-sorted sedimentary environments including sand beaches and high turbid regions of fine grained cohesive sediments. (omitted)

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Some Computational Contribution on the Estimation Procedure of a First Order Moving Average

  • Kim, Dai-Young
    • Journal of the Korean Statistical Society
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    • v.2 no.1
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    • pp.9-15
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    • 1973
  • In the first-order moving average model, we present the exact likelihood equations as function of variance, correlation and parameters of coefficients in the orthogonally transformed model. Existence of maximum likelihood estimates for these unknowns are studied and a computational method is provided. (Because of the limited space Ive do not present the computer program which is written in FORTRAN.) 40 sets of generated data and economic data are used to demonstrate, and few of them are presented in the Appendix. A numerical comparison of MLE with the efficient estimate proposed by Durbin is presented in the particular case.

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The System Performance of Wireless CSMA/CA Protocol with Capture Effect

  • Dai, Jiang-Whai
    • Journal of Communications and Networks
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    • v.6 no.3
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    • pp.226-234
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    • 2004
  • This work presents a deterministic channel that rules according to inverse a power propagation law. The proposed channel model allows us to derive the lower bound and upper bound of packet's capture probability in Rayleigh fading and shadowing cellular mobile system. According to these capture probabilities, we analyze the system performance in the case of finite stations and finite communicated coverage of a base station. We also adopted a dynamic backoff window size to discuss the robustness of IEEE 802.11 draft standard. Some suggestions and conclusions from numerical results are given to establish the more strong CSMA/CA protocol.

A study on development of continuity process system for thin film solar cell (박막 태양전지 연속 생산 시스템 개발에 관한 연구)

  • Bae, Sung-Woo;Jo, Jeong-Dai;Kim, Dong-Soo;Yoo, Seong-Yeon
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.377-377
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    • 2009
  • Currently, new and renewable energy come into the spotlight, such as solar energy, wind power, fuel cell, hybrid car etc., due to the energy resources is being depleted. In order to solve like this problem, we addressed the roll to roll printing machine for the thin film solar cell by using printing technology. For the this research, we archived concept design and verified propriety.

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A Note on Methodologies Used in I-O Forecasting Model

  • Kim, Dai-Young
    • Journal of the Korean Statistical Society
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    • v.5 no.1
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    • pp.35-48
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    • 1976
  • Since the solution vector for input-output forecasting models is not directly obtainable, several iterative procedures have been proposed and utilized. As is often the case in numerical analysis, the question of the consistency between the original system and the converged system of the proposed iteration has been ignored, and no one has tried to express the converged solution explicitly. This paper examines this question and points out the inconsistencies between various well-known iterative procedures used to solve input-output models and the original input-output system.

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