• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.143-145
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• 2005

In this paper, an empirical study result on pattern estimation method is devoted to reveal underlying data patterns with a relatively reduced computational cost. Presented method performs crisp type clustering with given n number of data samples by means of the sequential agglomerative hierarchical nested model (SAHN). Conventional SAHN based clustering requires large computation time in the initial step of algorithm. To deal with this concern, we modified overall process with a partial approach. In the beginning of this method, we divide given data set to several sub groups with uniform sampling and then each divided sub data group is applied to SAHN based method. The advantage of this method reduces computation time of original process and gives similar results. Proposed is applied to several test data set and simulation result with conceptual analysis is presented.

• 한국지반공학회지:지반
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• 제8권4호
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• pp.41-50
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• 1992

In general, the conceptual lumped-parameter groundwater flow model to predict the groundwater fluctuations in hillside slopes has unknown model parameters to be estimated from the known input -output data. The purpose of this study is to estimate the optimal model parameters of the groundwater flow model developed by authors. The Mazilnum A Posteriori( MAP) estimation method is utilized for this purpose and it is applied to a site which shows the typical landslide in Korea. The result of application shows tllat the 반AP estimation method can estimate the unknown parameters properly well. The groundwater model developed along with estimation technique applied in this paper will be used for assessing risk of landslides.

• 한국항행학회논문지
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• 제27권1호
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• pp.77-95
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• 2023

본 연구에서는 반복 설계를 통한 틸트 + 정지로터형 전기추진 수직이착륙 항공기(eVTOL)의 개념설계를 수행하였다. 현대자동차의 S-A1을 기준 형상으로 하여 도심항공모빌리티(UAM)의 개념을 사용하여 임무 형상을 정의하고 OpenVSP, XFLR5 소프트웨어를 사용하여 형상 설계와 공력해석을 수행하였다. 설계된 형상을 바탕으로 필요 동력을 추정한 뒤 배터리의 요구성능과 최대 이륙 중량(MTOW)을 계산하였다. Microsoft Excel과 Visual Basic Application을 사용해 반복적으로 계산하였으며, 이 과정에서 전기모터의 중량 추정식을 새롭게 고안하였다. 또한 자동화된 프로그램을 이용하여 eVTOL의 설계변수별 민감도 분석을 수행하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제16권2호
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• pp.54-58
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• 2014

High-temperature superconducting (HTS) rotating machines always require an electric current of from several hundreds to several thousand amperes to be led from outside into cold region of the field coil. Heat losses through the current leads then assume tremendous importance. Consequently, it is necessary to acquire optimal design for the leads which would achieve minimum heat loss during operation of machines for a given electrical current. In this paper, conduction cooled current lead type of 10 MW-Class HTS rotating machine will be chosen, a conceptual design will be discussed and performed relied on the least heat lost estimation between conventional metal lead and partially HTS lead. In addition, steady-state thermal characteristic of each one also is considered and illustrated.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2348-2354
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• 2018

We designed a conceptual model of the 2.3-BDO dehydration process using a hydroxyapatite-alumina catalyst and estimated its economic feasibility to predict the appropriate range of the purchase price of 2,3-BDO on commercial scale. The conceptual design and economic analysis can offer valuable information for the industrial application of 2,3-BDO because the most relevant studies have limitation in laboratory scale. Furthermore, the adequate range of 2,3-BDO price, in which the process has profitability, was investigated with the current market prices of 1,3-BD. The investigated price in terms of 2,3-BDO dehydration can pertain to estimation of the economic feasibility in 2,3-BDO production process.

• 한국항공우주학회지
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• 제46권1호
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• pp.32-40
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• 2018

본 논문에서는 개념설계 단계에서 주로 사용되는 통계적 중량 예측식 도출 방법에 관한 연구를 수행하였으며 Microsoft Excel을 이용해 이를 프로그램화하고 제트 여객기에 적용하여 검증하였다. 기존 중량 예측식들의 변수들을 참고하여 데이터베이스를 구축하였고 이를 사용하여 제트 여객기 날개 중량 예측식을 모델링하였다. 모델의 과적합 문제를 해결하기 위해 K-fold cross validation 방법을 사용하여 모델을 평가하였다.

• 한국항공우주학회지
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• 제40권4호
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• pp.364-374
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• 2012

본 연구에서는 발사체의 개념설계 단계 동안 성능 변수뿐만 아니라 신뢰성에 따른 개발비용 추정방안을 분석하고자 하였다. 과거에는 발사체의 개발비용을 예측하기 위해서 주로 발사체의 성능과 건조 질량 등을 독립변수로 하는 추정 방법이 많이 이용되었다. 이러한 접근 방법은 비교적 근사하였지만 신뢰성 수준에 따른 비용 변화를 반영할 수 없기 때문에 원하는 신뢰성을 가진 발사체의 개발비용을 근접하게 예측하기는 쉽지 않았다. 본 논문에서는 이러한 비용추정 방법의 한계를 개선하기 위해 성능과 질량을 기반으로 한 비용 모델인 TRANSCOST에 신뢰성 개념을 도입하여 발사체 비용을 추정할 수 있는 방법론을 제시하였다. 이를 기반으로 신뢰성에 따른 한국형발사체(KSLV- II)의 개발비용을 추정했다.

• 한국실내디자인학회논문집
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• 제19호
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• pp.30-37
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• 1999

This study presents a methods on the construction of integrated system for the purpose of automation of design plans, calculation of quantity of materials and estimation by abstracting information on building materials which is produced on the course of three dimension modeling by using computer. Therefore, an object oriented methodology is introduced to compose design informations in three dimension, space for unifying building informations, and expressing properties of building factors and materials, and to construct a database for computers to recognize architecture informations. An object indicates a conceptual individual existing in real world or existence of individual and necessity in composing a building could be called as objects such as column, wall, beam, slab, door and window and these contain materiality and immateriality. It is systemized to which properties of these building's objects are installed by the user of computer and by API(Application Programming Interface), chosen informations automatically converse to each unit work such as design plan structure plan, calculation of amount of materials, etc.

• 한국정보처리학회논문지
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• 제4권6호
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• pp.1401-1417
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• 1997

본 연구는 데이터 센터 Outsourcing에 관련된 비용 중에서 가장 산정하기 복잡하고 곤란한 기기 운영 비용을 합리적으로 산정할 수 있는 방법을 제시한다. 이를 위해서 Outsourcing 관련 문헌 조사를 통해 Outsourcing 비용 산정의 기본적인 개념을 정립하고 실제적인 Outsourcing 사례를 분석하여 기기 운영 비용을 합리적으로 산출할 수 있는 새로운 방법을 제시한다. 그리고 제시된 비용 산정 방법은 기존 방법과의 정량적인 비교 분석을 통하여 타당성을 검증하고 고객사의 담당자들을 대상으로 설문조사를 실시하여 새로운 비용 산정 방법의 합리성과 유용성을 실증적으로 검증한다.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.417-424
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• 2009

For a construction project to progress smoothly, effective cost estimation is vital, particularly in the conceptual and schematic design stages. In these early phases, despite the fact that initial estimates are highly sensitive to changes in project scope, owners require accurate forecasts which reflect their supplying information. Thus, cost estimators need effective estimation strategies. Practically, parametric cost estimates are the most commonly used method in these initial phases, which utilizes historical cost data (Karshenas 1984, Kirkham 2007). Hence, compilation of historical data regarding appropriate cost variance governing parameters is a prime requirement. However, precedent practice of data mining (data preprocessing) for denoising internal errors or abnormal values is needed before compilation. As an effort to deal with this issue, this research proposed a statistical methodology for data preprocessing and verified that data preprocessing has a positive impact on the enhancement of estimate accuracy and stability. Moreover, Statistically Preprocessed data Based Parametric (SPBP) cost models are developed based on multiple regression equations and verified their effectiveness compared with conventional cost models.