• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.177-185
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• 2000

The adjoint method is a method of data assimilation to improve the model results by seeking for model parameters that minimize the cost function and satisfy the governing equations of a model simultaneously. An adjoint package was set up for the two-dimensional linear tidal model and was applied to an idealized domain for an optimal estimation of the open boundary conditions. The assimilating data were selected from the results of forward modeling. Attention is paid on the response of the adjoint package to weighting parameters, the importance of initial estimates of model parameters and the applicability of the adjoint package to the case with varying depth. A procedure to determine optimal weight is presented based on the relationships between weights and other factors.

• Journal of the Korea Computer Industry Society
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• v.5 no.4
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• pp.471-480
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• 2004

A estimating capability of software effort, duration and cost is based on accurate size estimate of the software to be developed. A simplified function point (FP) approach to software size estimation is described, which first skip the computation step for value adjustment factor, thus directly obtaining final adjusted FP from unadjusted FP. The research seeks suitable models based on statistical regression models in the context of case study based on 783 software projects. The approach also are built for subsets of projects using new development, enhancement and re-development types.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.798-801
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• 2019

역사적으로 생명 보험은 상호부조의 형태로 갑작스럽게 어려운 상황이 발생하여도 경제적 어려움으로부터 가정을 지키는 역할을 해 왔다. 이는 평상 시에 만약의 경우를 대비하여 일정 비용을 지불함으로써 한 가정의 보장을 잘 준비하였기 때문이다. 하지만 한 가정의 경제적 상황은 지속적으로 변하기 때문에 시간이 지남에 따라 청약 당시의 보장 상태가 적절히 유지되고 있음을 확신할 수 없게 된다. 따라서 본 연구에서는 가처분 소득 추정 모델 개발을 통해 기존에 생명보험에 가입한 고객의 가처분 소득을 추정함으로써 고객에게 적절한 보장 강화의 기회를 제공하도록 한다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.42-54
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• 2019

Crop models depend on a large number of input parameters including the cultivar parameters that represent the genetic characteristics of a given cultivar. The cultivar parameters have been estimated using high quality data for crop growth, which require considerable costs and efforts. The objective of this study was to examine the feasibility of using low quality data for the parameter estimation. In the present study, the cultivar parameters for cv. Shindongjin were estimated using the data obtained from the report of new cultivars development and research from 2005 to 2016. The root mean square errors (RMSE) of the heading dates were less than 3 days when the parameters associated with phenology were estimated. In contrast, the coefficient of determination for yield tended to be less than 0.1. The large errors incurred by the fact that no growth data collected over a season was used for parameter estimation. This suggests that detailed observation data needs to be prepared for parameter calibration, which would be aided by remote sensing approaches. The occurrence of natural disasters during a growing season has to be considered because crop models cannot take into account the effects of those events. Still, our results provide a reasonable range for the parameters, which could be used to set the boundary of a given parameter for cultivars similar to cv. Shindongjin in further studies.

• Journal of IKEEE
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• v.17 no.4
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• pp.434-439
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• 2013

Artificial landmarks have been widely used for reducing the uncertainty in localization of a mobile robot. In addition, research for efficient placement of artificial landmarks has been considered as one of the fundamental issues since the cost of localization is increased with the number of used landmarks. Therefore, this paper proposes a method in which landmarks are efficiently placed by considering the uncertainty characteristics of the motion model and the sensor model. Because two models have different uncertainty distributions, the final uncertainty can be considerably reduced through their efficient combination. The usefulness of the proposed method is demonstrated by simulation results.

• Korean Journal of Construction Engineering and Management
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• v.22 no.3
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• pp.69-78
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• 2021

Estimated construction cost is an important index to secure an optimal budget which needs to go into construction projects in the previous of basic design phase. In order for public institutions to calculate the estimated construction cost, the cost per unit area of public buildings is used. However, the current calculation method of the estimated construction cost in public buildings is impossible to reflect the characteristics of many facilities and combinations. The purpose of this study is to develop an estimation model in the previous of basic design phase for the elementary, middle and high school facilities. it is expected that it is possible to estimate the construction cost of the elementary, middle and high schools in a reasonable and reliable manner through the estimation model developed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.677-684
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• 2008

The paper provides an approximate cost estimating model that can be used for tunnel. Based on the previous study analyzed critical factors that have impact on tunnel construction cost, this paper establishes a cost variance index table that reflects the cost impacts due to the change of the critical cost factors. An estimating procedure is described utilizing the index table. For the verification of the suggested model, the comparison of the estimated construction cost with real project cost is performed. The estimated results range from 95%~111% of the real project costs. As an approximate tunnel cost estimating model, the model can be utilized to quickly estimate tunnel construction costs based on the conceptual information at the planning stage and to efficiently make a decision on design alternatives.

• Journal of Environmental Policy
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• v.9 no.1
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• pp.31-55
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• 2010

This study aims to estimate potential climate change damage in Korea using the PAGE model. This study reviewed previous a reasearch to compare relative sensitivity to climate change in Korea and other regions to generate climate change damage function. It was found that sensitivity to climate change in Korea is similar to other Organization for Economic Cooperation and Development (OECD) countries. This study estimated climate change impact for three scenarios. If no action is taken, climate change damage cost in Korea could reach US$ 12,928 ~ 57,900 M. Cumulative Net Present Value (NPV)of climate change impact from 1990 to 2100 would be between US$ 143,226 ~ 921,701 Mdepending on emission scenarios. However, this result should be interpreted with caution as it draws its damage function based on only a few available references. Results also showed that an adaptation policy could decrease the degree of climate change impact significantly. If an adaptation policy is implemented, climate change impact will be decreased by US$ 11,355 million dollars in Korea in 2100.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.72-78
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• 2019

The second-hand ship market provides immediate access to the freight market for shipping investors. When introducing second-hand vessels, the precise estimate of the price is crucial to the decision-making process because it directly affects the burden of capital cost to investors in the future. Previous studies on the second-hand market have mainly focused on the market efficiency. The number of papers on the estimation of second-hand vessel values is very limited. This study proposes an artificial neural network model that has not been attempted in previous studies. Six factors, freight, new-building price, orderbook, scrap price, age and vessel size, that affect the second-hand ship price were identified through literature review. The employed data is 366 real trading records of Panamax second-hand vessels reported to Clarkson between January 2016 and December 2018. Statistical filtering was carried out through correlation analysis and stepwise regression analysis, and three parameters, which are freight, age and size, were selected. Ten-fold cross validation was used to estimate the hyper-parameters of the artificial neural network model. The result of this study confirmed that the performance of the artificial neural network model is better than that of simple stepwise regression analysis. The application of the statistical verification process and artificial neural network model differentiates this paper from others. In addition, it is expected that a scientific model that satisfies both statistical rationality and accuracy of the results will make a contribution to real-life practices.

• Journal of the Korean Home Economics Association
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• v.40 no.12
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• pp.63-83
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• 2002

본 연구는 미국 소비자들이 지각한 온라인 쇼핑속성에 대한 차원을 밝히고. 온라인 속성에 대한 중요성과 상품범주별 구매의도와의 관계를 밝혀 상품범주별 마케팅 전략과 인터넷 소비자 관리 및 교육 프로그램 개발에 기여하고자 하였다. 조사대상자는 가정에서 인터넷을 사용하고 있는 미국 소비자 303 명으로 구성되었으며, 질문지법에 의해 자료 수집되었다. 자료분석을 위해 탐색적 요인분석을 실행하였고, LISREL8에 의해 측정모델과 구조적 관계 모델을 동시에 검증하였다. 자료 분석결과를 요약하면 다음과 같다. 첫째, 소비자가 지각한 온라인 쇼핑에 대한 속성은 거래 및 비용, 사이트 디자인, 구매유인 프로그램, 상호 관계성의 4개 차원으로 분류되었다. 둘째, 온라인 상품은 구매의도에 따라 인지적 상품, 경험적 상품, 서비스 3개 범주로 분류되었다. 셋째, 지각된 온라인 쇼핑속성의 중요도와 각상품군 구매의도와의 구조적 관계모델을 추정한 결과,“거래 및 비용”은 3개의 상품군에 대한 구매의도에 모두 유의한 영향을 주었으며,“구매유인 프로그램”은 경험적 상품과 서비스에 대한 구매의도에 유의한 영향을 미쳤다. 따라서, 소비자들에게 중요하게 지각되는 인터넷 특정 속성 즉, 보완, 배달 및 비용을 초점으로한 상품범주별 차별화된 이점을 제시하여 효과적인 마케팅 전략을 수립해야 할 것이다. 또한, 전자 상거래와 관련 보완, 환불정책 등에 관한 소비자 교육과 보호법이 요구되고 있다.