• Journal of the Korean Statistical Society
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• 제32권4호
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• pp.385-399
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• 2003

We first introduce the quasi-score estimating function and applied the quasi-score estimating function to nonlinear time series models. We proposed the M quasi-score estimating functions bounded functions for the quasi-score estimating functions. Also, we investigated the asymptotic properties of quasi-likelihood estimators and M quasi-likelihood estimators. Simulation results show that the M quasi-likelihood estimators work better than the least squares estimators under the heavy-tailed distributions

• Communications for Statistical Applications and Methods
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• 제25권1호
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• pp.99-107
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• 2018

This article considers a robust Kalman filter from the M-estimation point of view. Pak (Journal of the Korean Statistical Society, 27, 507-514, 1998) proposed a particular M-estimating function which has the data-based shaping constants. The Kalman filter with the proposed M-estimating function is considered. The structure and the estimating algorithm of the Kalman filter accompanying the M-estimating function are mentioned. Kalman filter estimates by the proposed M-estimating function are shown to be well behaved even when data are contaminated.

• 한국군사과학기술학회지
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• 제13권4호
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• pp.601-611
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• 2010

Currently, a life cycle cost estimates(LCCE) is the most important factor in weapon system acquisition process. However, operation and maintenance(O&M) cost related studies are insufficient from the previous literature survey. O&M cost consists of various cost factors such a man power, maintenance and direct & indirect support costs. We have known that spare-parts cost is a key factor in the O&M cost. In this paper, we developed the spare-parts cost estimating relationships(CERs) of fixed-wing aircraft and armored vehicle weapon systems which include 4 historical cost drivers ; system acquisition cost, deterioration rate, localization rate, mission characteristic. Furthermore, we proposed the application methodologies that O&M cost estimating, total life cycle cost estimating and determination of the economic life using the spare-parts CERs.

• Journal of the Korean Statistical Society
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• 제36권3호
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• pp.387-395
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• 2007

We propose a doubly robustified estimating function for the estimation of parameters in the context of ARCH models. We investigate asymptotic properties of estimators obtained as solutions of robust estimating equations. A simulation study shows that robust estimator from specified doubly robustified estimating equation provides better performance than conventional robust estimators especially under heavy-tailed distributions of innovation errors.

• 비파괴검사학회지
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• 제29권3호
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• pp.230-234
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• 2009

As concrete ages, the surrounding environment is expected to have growing influences on the concrete. As all the impacts of the environment cannot be considered in the strength-estimating model of a nondestructive concrete test, the increase in concrete age leads to growing uncertainty in the strength-estimating model. Therefore, the variation of the model error increases. It is necessary to include those impacts in the probability model of concrete strength attained from the nondestructive tests so as to build a more accurate reliability model for structural performance evaluation. This paper reviews and categorizes the existing strength-estimating statistical models of nondestructive concrete test, and suggests a new form of the strength-estimating statistical models to properly reflect the model uncertainty due to aging of the concrete. This new form of the statistical models will lay foundation for more accurate structural performance evaluation.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1201-1208
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• 2009

A making a decision of construction cost has important meaning and function for both contractor and owner in construction projects. Especially, it should be premised that estimating the construction cost in efficient and rational way in public construction, which is invested by government funds, for efficient execution of the budget and investment as a side of government. The systematic methodology for estimating construction cost approximately of a river facility construction project has not yet been established because of its unique characteristics including its relatively small project size in terms of cost. On this study, It collect and analyze a river facility construction historical cost data for develop an approximate cost estimating model for river applied by typical embankment section method and rate application of the others activity type. And it verify suitability of model through a that result of application of real river facility construction statement at developed model. By this study, it is expected to reasonable and systematic estimating construction cost through application of developed model.

• 대한조선학회논문집
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• 제48권5호
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• pp.426-434
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• 2011

Accurate weight prediction methods are an essential of the ship design in both ship cost managements and performance satisfactions. When no parent or similar ships are available, an adequate method of the ship weight estimating is required. In this study, there was carried out to develop the ship weight estimating method for the preliminary design phase. The weight estimating methods were first surveyed by the references and summarized their characteristics. The weight estimation method by statistical approach was developed for the container ship because the containerized transportation markets is gradually growing and ship's size and loading capacity are rapidly enlarged. The correlation analysis and the multiple regression analysis were used for developing the weight estimating method. As a results of evaluating the developed method, the error ratio of the variation between estimated weight and ship's data was about 5%. And it was only 1% difference with the calculating weight of conceptual design results by shipyard design team that the estimating weight of ultra-large container ship was predicted by the developed method.

• 한국재난정보학회 논문집
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• 제10권1호
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• pp.15-24
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• 2014

본 연구는 설계 과정의 분해, 시공 과정의 조립, 공사비 적산 등 공사의 계획과 관리에 걸친 모든 공사 관리의 업무를 체계화할 수 있는 공동주택의 공사정보분류체계를 제시하였다. 또한, 본 연구는 이 공사정보분류체계를 작업순서에 따라 관계형 데이터베이스(Data Base)로 구축 방법을 제시하였고, 구축된 데이터베이스를 근거로 적산 자동화 시스템 개념 모형을 구축하였다. 이러한 적산 자동화 시스템 개념 모형은 기존 적산 시스템들의 근본적인 문제점이었던 부적절함을 해소하여 공동주택 건설현장에서 효과적으로 적용가능한 과학적인 적산 시스템으로 활용할 수 있을 것이다.

• 산업경영시스템학회지
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• 제34권3호
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• pp.49-56
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• 2011

Estimating optimum hardware capacity of an e-learning system is very important process to grasp reasonable size of designing technique architecture and budget during step of ISP(information strategic planning) and development. It hugely influences cost and quality of the whole project. While investment on information system hardware has been continuously increased, there was no certified hardware capacity estimating method in e-learning system development. A guideline for hardware sizing of information systems was established by Telecommunication Technology Association in 2008. However, the guideline is not appropriate for estimating optimum hardware capacity of an e-learning system because it was designed to provide general standards for estimating hardware capacity of various types of projects. The purpose of this paper is to provide a methodology for estimating optimum hardware capacity in e-learning system development. To develop the methodology, this study, first of all, analyzes two e-learning development projects, in which the guideline was applied to estimate optimum hardware capacity. Then, this study finds out several key factors influencing on hardware capacity. Finally, this study suggests a methodology for estimating optimum hardware capacity of an e-learning system, in which weights for the factors are determined through AHP analysis.

• Journal of the Korean Data and Information Science Society
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• 제13권1호
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• pp.47-53
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• 2002

A new redescending M-estimating function is introduced. The estimators by this new redescending function attain the same level of robustness as the existing redescending M-estimators, but have less asymptotic variances than others except few cases. We have focused on estimating a location parameter, but the method can be extended for a scale estimation.