• 제목/요약/키워드: L-series

검색결과 1,443건 처리시간 0.03초

THE OVERLAPPING SPACE OF A CANONICAL LINEAR SYSTEM

  • Yang, Meehyea
    • Journal of applied mathematics & informatics
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    • 제16권1_2호
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    • pp.461-468
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    • 2004
  • Let W(z) be a power series with operator coefficients such that multiplication by W(z) is contractive in C(z). The overlapping space $L(\varphi)$ of H(W) in C(z) is a Herglotz space with Herglotz function $\varphi(z)$ which satisfies $\varphi(z)+\varphi^*(z^{-1})=2[1-W^{*}(z^{-1})W(z)]$. The identity ${}_{L(\varphi)}={-}_{H(W)}$ holds for every f(z) in $L(\varphi)$ and for every vector c.

AUTOCORRELATION FUNCTION STRUCTURE OF BILINEAR TIME SREIES MODELS

  • Kim, Won-Kyung
    • Journal of the Korean Statistical Society
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    • 제21권1호
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    • pp.47-58
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    • 1992
  • The autocorrelation function structures of bilinear time series model BL(p, q, r, s), $r \geq s$ are obtained and shown to be analogous to those of ARMA(p, l), l=max(q, s). Simulation studies are performed to investigate the adequacy of Akaike information criteria for identification between ARMA(p, l) and BL(p, q, r, s) models and for determination of orders of BL(p, q, r, s) models. It is suggested that the model of having minimum Akaike information criteria is selected for a suitable model.

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Synthesis of Pyrazoloquinolines as Gastric $H^+/K^+$-ATPase Inhibitors

  • G. D. Kalayanov;Kang, S. K.;Cheon, H.G.;Lee, S.G.;Yum, E. K.;Kim, S. S.;Choi, J.-K.
    • Bulletin of the Korean Chemical Society
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    • 제19권6호
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    • pp.667-671
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    • 1998
  • A series of 1-aryl-lH-pyrazolo[4,3-c]quinolines and 2-aryl-2H-pyrazolo[4,3-c]quinolines are prepared by reacting 3-acyl-4-chloroquinolines in ethanol or 3-acyl-4(lH)-quinolone in acetic acid with appropriate hydrazines as possible anti-ulcer agents. A regiospecific synthesis of 1-aryl-lH-pyrazolo[4,3-c]quinolines is also achieved. The central pyridine ring could be easily reduced by catalytic hydrogenation.

용접방향에 따른 오스트나이트계 스테인리스강(STS304L) 용착금속파단 용접접합부의 내력에 관한 실험적 연구 (Experimental Study on Strength of Austentic Stainless Steel (STS 304L) Fillet-Welded Connection with Weld Metal Fracture According to Welding Direction)

  • 김태수;이후창;황보경;조태준
    • 한국구조물진단유지관리공학회 논문집
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    • 제22권1호
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    • pp.81-89
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    • 2018
  • 오스테나이트계 스테인리스강은 우수한 내식성, 내구성 및 내화성을 지닌다. 특히, 오스테나이트계 스테인리스강중의 대표인 STS304에 비해 저탄소를 함유하고 있는 STS304L은 현장용접 후 별도의 열처리 없이 높은 내입계부식성능을 지니고 있어 용접후 내입계 부식이 우려되는 부재 접합에 적용할 수 있다. 본 연구에서는 티그(TIG)용접으로 필릿 용접된 STS304L 용접접합부의 용접재(용착금속부) 내력과 파단 메카니즘을 조사하고자 한다. 주요변수인 하중방향에 대한 용접선의 배치에 따라 TFW(하중직각방향 용접), LFW(하중방향용접), FW(하중방향용접과 하중직각방향 용접조합)시리즈의 실험체를 제작하여 인장실험을 실시하였고, 각각 인장파단,전단파단, 블록전단파단(인장파단과 전단파단의 조합)이 발생하였다. 동일 용접길이에 대해 TFW 시리즈의 접합부가 가장 높은 내력을 나타났으며, 현행기준식(KBC2016/AISC2010)과 기존 연구자의 식에 의한 예측내력과 비교한 결과, TFW와 LFW접합부는 과소평가되었고 FW실험체는 과대평가되었다. 실제 파단 위험단면과 블록전단파단 메카니즘을 고려한 내력식을 제안하였다.

L-모멘트법에 의한 적정 설계홍수량의 유도 (Derivation of Optimal Design Flood by L-Moments)

  • 이순혁;박명근;맹승진;정연수;김동주;류경식
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 1998년도 학술발표회 발표논문집
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    • pp.318-324
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    • 1998
  • This study was conducted to derive optimal design floods by Generalized Extreme-value(GEV) distribution for the annual maximum series at ten watersheds along Han, Nagdong, Geum, Yeongsan and Seomjin river systems. Adequacy for the analysis of flood data used in this study was established by the tests of Independence, Homogeneity, detection of Outliers. L-coefficient of variation, L-skewness and L-kurtosis were calculated by L-moment ratio respectively. Parameters were estimated by the Methods of Moments and L-Moments. Design floods obtained by Methods of Moments and L-Moments using different methods for plotting positions in GEV distribution were compared by the relative mean and relative absolute error. It was found that design floods derived by the method of L-moments using weibull plotting position formula in GEV distribution are much closer to those of the observed data in comparison with those obtained by method of moments using different formulas for plotting positions in view of relative mean and relative absolute error.

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STABILITY THEOREM FOR THE FEYNMAN INTEGRAL APPLIED TO MULTIPLE INTEGTALS

  • Kim, Bong-Jin
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제8권1호
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    • pp.71-78
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    • 2001
  • In 1984, Johnson[A bounded convergence theorem for the Feynman in-tegral, J, Math. Phys, 25(1984), 1323-1326] proved a bounded convergence theorem for hte Feynman integral. This is the first stability theorem of the Feynman integral as an $L(L_2 (\mathbb{R}^N), L_2(\mathbb{R}^{N}))$ theory. Johnson and Lapidus [Generalized Dyson series, generalized Feynman digrams, the Feynman integral and Feynmans operational calculus. Mem, Amer, Math, Soc. 62(1986), no 351] studied stability theorems for the Feynman integral as an $L(L_2 (\mathbb{R}^N), L_2(\mathbb{R}^{N}))$ theory for the functional with arbitrary Borel measure. These papers treat functionals which involve only a single integral. In this paper, we obtain the stability theorems for the Feynman integral as an $L(L_1 (\mathbb{R}^N), L_{\infty}(\mathbb{R}^{N}))$theory for the functionals which involve double integral with some Borel measures.

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스테인레스계열(17-4PH, 316L, 440C) 분말을 이용한 Dental Scaler Tip 분말사출금형 개발 (Development of Powder Injection Mold for Dental Scaler Tip Using Stainless Series Powder)

  • 고영배;김종선;황철진
    • 소성∙가공
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    • 제16권1호
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    • pp.61-66
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    • 2007
  • Powder injection molding(PIM) is widely used for many parts in the field of automotives, electronics and medical industries, due to the capability of net shaping for complex 3-D geometry. Powder injection mold design for the dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip which has complex geometry. Both product design and mold design for dental scaler tip were presented. A PIM feedstock was made of stainless series(17-4PH, 316L, 440C) powder and a wax based binder. The 'rapid mold' concept was applied to manufacture the various forms and materials of dental scaler tip including vibration characteristics.

Estimating Reorder Points for ARMA Demand with Arbitrary Variable Lead Time

  • An, Bong-Geun;Hong, Kwan-Soo
    • 한국경영과학회지
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    • 제17권2호
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    • pp.91-106
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    • 1992
  • It an inventory control system, the demand over time are often assumed to be independently identically distributed (i. i. d.). However, the demands may well be correlated over time in many situations. The estimation of reorder points is not simple for correlated demands with variable lead time. In this paper, a general class of autoregressive and moving average processes is considered for modeling the demands of an inventory item. The first four moments of the lead-time demand (L) are derived and used to approximate the distribution of L. The reorder points at given service level are then estimated by the three approximation methods : normal approximation, Charlier series and Pearson system. Numerical investigation shows that the Pearson system and the Charlier series performs extremely well for various situations whereas the normal approximation show consistent underestimation and sensitive to the distribution of lead time. The same conclusion can be reached when the parameters are estimated from the sample based on the simulation study.

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