• 대한전기학회논문지
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• 제39권8호
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• pp.868-874
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• 1990

A singular value approach is presented in order to determine the number of multiple sinusoids from the finite noisy data. Simulations are conducted for Akaike's information criterion (AIC), Rissanen's shortest data description (MDL) and a singular value approach, for various examples with different SNR's and methods of estimating frequencies. And then the performances are compared. Simulation results that the singular value approach is superior to AIC and MDL for FBLP, HOYW and covariance matrix based methods are investigated. The approach with contribute to the frequency estimation of multiple sinusoids from the finite noisy data. Furthermore, this will be applied to the DSPs of communication and bio-medical engineering.

• 응용통계연구
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• 제16권2호
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• pp.365-376
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• 2003

본 연구에서는 비정규 시계열 자료에 관한 다양한 회귀모형을 고찰하고, 이들 모형의 선택 기준에 관하여 연구해 보았다. 모형 선택의 기준으로는 AIC (Akaike information criterion), BIC (Baysian information criterion) 그리고 우도비 검정을 확장 적용하였다. 또한, 실제의 Polio 자료분석을 통해 이를 적용해보았다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.719-723
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• 2004

본 연구에서는 일 최고, 최소치 유출량 계열을 확충하기 위해 ARIMA(p,d,q) 모형을 이용하였으며, 분석 자료의 경향성 유무를 파악하기 위해 Mann-Kendal 비모수적 검정을 실시하였다. 분석 결과, 최고 최소 유출량 자료 모두 경향성이 없는 것으로 분석되었다. ARIMA(p,d,q) 모형의 최적 차수를 결정하기 위해 ACF, PACF, AIC, 그리고 SBC(Schwarz Bayesian Criterion) 검사를 실시하였으며 이를 통해 최적의 ARMA 모형을 결정하였다. 일 최대치 자료의 경우 추계학적 경향 보다는 무작위적 특성을 보였으며, 일 최소치 자료계열 경우, ARMA(1,0) 모형이 최적 모형으로 선정되었다.

• 대한전기학회논문지:전력기술부문A
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• 제52권8호
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• pp.450-456
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• 2003

This paper proposes a multiple time-series model with dummy variables for one-hour ahead load forecasting. We used 11 dummy variables that were classified by day characteristics such as day of the week, holiday, and special holiday. Also, model specification and selection of input variables including dummy variables were made by test statistics such as AIC(Akaike Information Criterion) and t-test statistics of each coefficient. OLS (Ordinary Least Squares) method was used for estimation and forecasting. We found out that model specifications for each hour are not identical usually at 30％ of optimal significance level, and dummy variables reduce the forecasting error if they are classified properly. The proposed model has much more accurate estimates in forecasting with less MAPE (Mean Absolute Percentage Error).

• 응용통계연구
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• 제5권2호
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• pp.181-192
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• 1992

본 논문에서는 텐서 스플라인을 이용하여, 일반화된 선형모형의 회귀합수를 자료에만 의존 하는 방식으로 추정하는 문제를 고려하였다. 최우 추정법을 이용하여 회귀 함수를 추정하는 데, 이용된 텐서 스틀라인은 접목점의 수가 유한개이며, 독립변수 영역의 주변에서는 선형으 로 제한되었다. 접목점을 자료의 각 좌표의 순서 통계량에 위치하도록 했고 그 수는 AIC의 변형된 식을 최소로 하는 수로 결정 했다. 모의 실험 예를 통하여 추정량을 예시하였다.

• 응용통계연구
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• 제5권2호
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• pp.271-282
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• 1992

자궁경부암을 대상으로 란게르한스 세포와 악성변화의 연관성을 연구할 때 사용할 수 있는 통계적 방법을 제시하였다. 포아슨 확률모형에 바탕을 두어 설정된 여러 가능한 부모형 가운데 관찰치에 가장 적합한 모형을 AIC유형의 모형선택 기준에 의하여 선택하였다. 모형선택 기준의 표본분포는 불스트？을 이용하여 근사시키고 추정량의 표본분포는 정규근사를 이용하여 구하였다.

• Advances in environmental research
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• 제3권2호
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• pp.131-149
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• 2014

Two different model selection indices, the Akaike information criterion (AIC) and the coefficient of determination ($R^2$), are used to discriminate competing isotherm equations for aqueous pollutant removal systems. The former takes into account model accuracy and complexity while the latter considers model accuracy only. The five types of isotherm shape in the Brunauer-Deming-Deming-Teller (BDDT) classification are considered. Sorption equilibrium data taken from the literature were correlated using isotherm equations with fitting parameters ranging from two to five. For the isotherm shapes of types I (favorable) and III (unfavorable), the AIC favors two-parameter equations which can easily track these simple isotherm shapes with high accuracy. The $R^2$ indicator by contrast recommends isotherm equations with more than two parameters which can provide marginally better fits than two-parameter equations. To correlate the more intricate shapes of types II (multilayer), IV (two-plateau) and V (S-shaped) isotherms, both indices favor isotherm equations with more than two parameters.

• 천문학회보
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• 제45권1호
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• pp.55.2-55.2
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• 2020

Radio relics in the outskirts of galaxy clusters are interpreted as synchrotron radiation due to the relativistic electrons produced via diffusive shock acceleration (DSA) in shocks with low sonic Mach numbers, Ms ≤ 3 in high beta ICM plasma. Electron injection into the DSA process at such weak shocks is one of the key elements, which has yet to be fully understood. In this study, we explore the nature of kinetic microinstabilities excited in weak quasi-perpendicular shocks through 2D particle-in-cell simulations. We find Alfven-ion cyclotron (AIC), whistler, and mirror instabilities can be triggered by ion and electron temperature anisotropy in the immediate downstream of supercritical shocks with Ms > Mcrit ~ 2.3. In particular, AIC instability causes rippling of the shock surface, which in turn generates plasma waves on multi-scales and faciliates the electron preacceleration. Our results may contribute to understanding the origins of radio relics.

• Communications for Statistical Applications and Methods
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• 제5권3호
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• pp.827-836
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• 1998

본 연구의 목적은 평활 적합도 검정에 이용되는 모형선택 기법 중 AIC (Akaike information criteria) 기법과 BIC (Baysian information criteria) 기법을 사용한 검정통계량들에 대한 검정력을 비교 분석함에 있다. 또한 이 두 가지 기법을 이용한 새로운 검정 통계 량을 제시하고 기존의 검정 통계량들과 비교 분석하였다.

• 한국재료학회지
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• 제22권4호
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• pp.190-194
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• 2012

The formation of high-quality polycrystalline silicon (poly-Si) on relatively low cost substrate has been an important issue in the development of thin film solar cells. Poly-Si seed layers were fabricated by an inverse aluminum-induced crystallization (I-AIC) process and the properties of the resulting layer were characterized. The I-AIC process has an advantage of being able to continue the epitaxial growth without an Al layer removing process. An amorphous Si precursor layer was deposited on Corning glass substrates by RF magnetron sputtering system with Ar plasma. Then, Al thin film was deposited by thermal evaporation. An $SiO_2$ diffusion barrier layer was formed between Si and Al layers to control the surface orientation of seed layer. The crystallinity of the poly-Si seed layer was analyzed by Raman spectroscopy and x-ray diffraction (XRD). The grain size and orientation of the poly-Si seed layer were determined by electron back scattering diffraction (EBSD) method. The prepared poly-Si seed layer showed high volume fraction of crystalline Si and <100> orientation. The diffusion barrier layer and processing temperature significantly affected the grain size and orientation of the poly Si seed layer. The shorter oxidation time and lower processing temperature led to a better orientation of the poly-Si seed layer. This study presents the formation mechanism of a poly seed layer by inverse aluminum-induced crystallization.