• 응용통계연구
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• 제29권4호
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• pp.581-594
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• 2016

본 논문은 이노베이션 상태공간모형을 근간으로 기존의 지수평활법을 포괄할 수 있는 다중 계절형 모형을 소개한다. 특히 이 모형은, 기존 모형의 한계를 극복하고 동일한 계절 내의 다양성을 표현할 수 있도록 계절 성분을 행렬로 표현하는 정교한 구조를 가지고 있다. 이런 구조를 이용하면 비슷한 패턴을 가지는 계절 성분의 모수를 그룹별로 분류할 수 있다. 따라서, 다중 계절형 모형은 모수절약 원칙을 달성할 수 있으며 모형의 해석이 용이한 장점을 가지고 있을 뿐만 아니라, 잠재적으로 임의의 개수의 계절성도 수용 가능하다. 본 연구에서는 다중 계절형 모형을 이용하여 시간 단위로 관측된 한국 전력 수요량을 분석하고 예측한다. 특히, 시간별 전력 수요량의 계절성은 1일 및 1주일의 두 가지로 고려되었고 이를 토대로 유사한 요일들은 공통 계절로 그룹화하였다. 모형의 예측 성능을 평가하기 위하여 기존 지수평활법의 예측 결과와 비교하였다. 그 결과, 다중 계절형 모형이 기존 지수평활법보다 예측력이 우수함을 확인하였다.

• 한국토양비료학회지
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• 제48권6호
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• pp.751-760
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• 2015

Management of renewable organic resources is important in attaining the sustainability of agricultural production. However, nutrient management with organic resources is more complex than fertilization with chemical fertilizer because the composition of the organic input or the environmental condition will influence organic matter decomposition and nutrient release. One of the most effective methods for estimating nutrient release from organic amendment is the use of N mineralization models. The present study aimed at parameterizing N mineralization models for a number of organic amendments being used as a nutrient source for crop production. Laboratory incubation experiment was conducted in aerobic condition. N mineralization was investigated for nineteen organic amendments in sandy soil and clay soil at $20^{\circ}C$, $25^{\circ}C$, and $30^{\circ}C$. N mineralization was facilitated at higher temperature condition. Negative correlation was observed between mineralized N and C:N ratio of organic amendments. N mineralization process was slower in clay soil than in sandy soil and this was mainly due to the delayed nitrification. The single and the double exponential models were used to estimate N mineralization of the organic amendments. N mineralization potential $N_p$ and mineralization rate k were estimated in different temperature and soil conditions. Estimated $N_p$ ranged from 28.8 to 228.1 and k from 0.0066 to 0.6932. The double exponential model showed better prediction of N mineralization compared with the single exponential model, particularly for organic amendments with high C:N ratio. It is expected that the model parameters estimated based on the incubation experiment could be used to design nutrient management planning in environment-friendly agriculture.

• 산업진흥연구
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• 제9권2호
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• pp.45-58
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• 2024

본 연구는 대전 지역에 위치한 연구소기업과 전국에 있는 연구소기업 고객사 간의 사회적 네트워크 구조 특성을 동종 기술 간 지역적 군집화 경향으로 모형화했고, ERGM(Exponential Random Graph Model) 분석 모형 대비 관측값이 95% 신뢰구간 내 포함되었다. 기업 모두 대전 유성구에 위치한 경우, 다른 행정구역에 속한 경우보다 연결 확률이 약 13배 높았을 뿐만 아니라 동종 기술을 가진 기업 간에는 구색성 및 동질성 값이 부의 값(0.1904)으로 활발한 연결 경향을 보였으며, 특히 6대 기술 중 '환경·에너지기술(ET)' 기업 간에 P값이 0.035로 가장 유의하였다. 유성구에 속하지 않은 기업 사이에는 음의 값(-0.0035)을 보이고, 군집 경향도 적었다. 이를 통해 대덕연구개발특구가 입지한 대전광역시 유성구가 혁신클러스터의 중심지 역할을 형성하고 있음을 확인할 수 있었다.

• Earthquakes and Structures
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• 제14권3호
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• pp.187-201
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• 2018

The paper describes a modified cyclic bar model including bond-slip phenomena between steel reinforcing bars and surrounding concrete. The model is focused on plain bar and is useful, for its simplicity, for the seismic analyses of RC structures with plain bars and insufficient constructive details, such as in the case of '60s -'70s Mediterranean buildings. The model is based on an imposed exponential displacements field along the bar including both steel deformation and slip; through the adoption of equilibrium and compatibility equations a stress-slip law can be deducted and simply applied, with opportune operations, to RC numerical models. This study aims to update and complete the original monotonic model published by the authors, solving some numerical inconsistencies and, mostly, introducing the cyclic formulation. The first aim is achieved replacing the imposed linear displacement field along the bar with an exponential too, while the cyclic behaviour is described through a formulation based on the results of parametric analyses concerning a large range of steel and concrete properties and geometric configurations. Validations of the proposed model with experimental results available in the current literature confirm its accuracy and the reduced computational burden, highlighting its suitability in performing nonlinear analyses of RC structures.

• Asian Journal of Business Environment
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• 제7권4호
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• pp.35-41
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• 2017

Purpose - This paper aims to examine several time series models to predict sales of department stores and discount store markets in South Korea, while other previous trial has performed sales of convenience stores and supermarkets. In addition, optimal predicted values on the underlying model can be got and be applied to distribution industry. Research design, data, and methodology - Two retailing types, under investigation, are homogeneous and comparable in size based on 86 realizations sampled from January 2010 to February in 2017. To accomplish the purpose of this research, both ARIMA model and exponential smoothing methods are, simultaneously, utilized. Furthermore, model-fit measures may be exploited as important tools of the optimal model-building. Results - By applying Holt-Winters' additive seasonality method to sales of two large-scale retailing types, persisting increasing trend and fluctuation around the constant level with seasonal pattern, respectively, will be predicted from May in 2017 to February in 2018. Conclusions - Considering 2017-2018 forecasts for sales of two large-scale retailing types, it is important to predict future sales magnitude and to produce the useful information for reforming financial conditions and related policies, so that the impacts of any marketing or management scheme can be compared against the do-nothing scenario.

• 한국국방경영분석학회지
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• 제11권1호
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• pp.1-7
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• 1985

A computer-aided simulation model for inventory control was developed using Apple II Plus micro-computer. The model forecasts quarterly demands with Single Exponential Smoothing method and simulates Supply Demand Review and Inventory Level Settings for each items. The simulation is based on the assumption that the demand occurrences have their own probability distributions.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1991년도 춘계공동학술대회 발표논문 및 초록집; 전북대학교, 전주; 26-27 Apr. 1991
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• pp.198-198
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• 1991

• Communications for Statistical Applications and Methods
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• 제22권6호
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• pp.531-542
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• 2015

In this survey, we use the normal linear model to demonstrate the use of the linear Bayes method. The superiorities of linear Bayes estimator (LBE) over the classical UMVUE and MLE are established in terms of the mean squared error matrix (MSEM) criterion. Compared with the usual Bayes estimator (obtained by the MCMC method) the proposed LBE is simple and easy to use with numerical results presented to illustrate its performance. We also examine the applications of linear Bayes method to some other distributions including two-parameter exponential family, uniform distribution and inverse Gaussian distribution, and finally make some remarks.

• Journal of the Korean Data and Information Science Society
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• 제5권2호
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• pp.75-85
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• 1994

계단 충격 가속수명시험에서 통계적 추론을 위해 가정하는 수명분포에 대한 적합도검정을 Kolmogorov-Smirnov, Kuiper, Watson, Cramer-von Mises, Anderson-Darling과 같은 비모수적 검정통계량에 대하여 몬테칼로 방법을 이용한 기각치를 구하고, 검정력 측면에서 비교, 연구한다.

• 대한기계학회논문집A
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• 제30권7호
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• pp.787-793
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• 2006

Recently kriging model has been widely used in the DACE (Design and Analysis of Computer Experiment) because of prominent predictability of nonlinear response. Since DACE has no random or measurement errors contrast to physical experiment, space filling experimental design that distributes uniformly design points over whole design space should be employed as a sampling method. In this paper, we examine the maximum entropy experimental design that reveals the space filling strategy in which defines the maximum entropy based on Gaussian or exponential. The influence of these two correlation functions on space filling design and their model parameters are investigated. Based on the exploration of numerous numerical tests, enhanced maximum entropy design based on exponential correlation function is suggested.