• 대한산업공학회지
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• 제3권2호
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• pp.63-72
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• 1977

The trend of computerization is significant in Korea even at its beginning stage, especially for governmental administration. However, full-fledged success of computerization in an organization is reported to be rare while the cost of computerization has been high and increasing. This paper is concerned with two features for the successful implementation of a computerized system in an organization selection criteria for the computerization among the possible candidate projects and project selection models. Due to the dearth of literature regarding successful implementation of computerization, other sources of literature with respect to R & D management, method engineering, etc. were reviewed to develop a set of factors influencing successful computerization. Thus, project selection criteria for computerization of governmental administration are developed and organized as follows: cost of computerization project including both system development and operating cost, quanitative and qualitative benefits of computerization project, probability of technical and implementation success of computerization and other organizational and political factors to be considered. These criteria are broken down into detailed sets of subcriteria to be measured. To select a project after thorough consideration of the selection criteria, a project selection model which takes into account all criteria together has to be developed. In the study three project selection models are suggested and developed. They are the checklist model, multi-stage cut-off model, and composite criteria model. A detailed procedure for each of the three models is illustrated. Although the project selection criteria and models are developed here primarily for the computerization of governmental administration, they are easily applicable to other settings of computerization. Finally, some caveats for the use of selection criteria and models are discussed.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제19권2호
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• pp.137-170
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• 2015

In this paper, we propose and analyze three viral infection models with humoral immunity including an eclipse stage of infected cells. The incidence rate of infection is represented by bilinear incidence and saturated incidence in the first and second models, respectively, while it is given by a more general function in the third one. The neutralization rate of viruses is giv0en by bilinear form in the first two models, while it is given by a general function in the third one. For each model, we have derived two threshold parameters, the basic infection reproduction number which determines whether or not a chronic-infection can be established without humoral immunity and the humoral immune response activation number which determines whether or not a chronic-infection can be established with humoral immunity. By constructing suitable Lyapunov functions we have proven the global asymptotic stability of all equilibria of the models. For the third model, we have established a set of conditions on the threshold parameters and on the general functions which are sufficient for the global stability of the equilibria of the model. We have performed some numerical simulations for the third model with specific forms of the incidence and neutralization rates and have shown that the numerical results are consistent with the theoretical results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.272-287
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• 2016

Recently, various and effective contrast based salient object detection models to focus on a single target have been proposed. However, there is a lack of research on detection of multiple objects, and also it is a more challenging task than single target process. In the multiple target problem, we are confronted by new difficulties caused by distinct difference between properties of objects. The characteristic of existing models depending on the global maximum distribution of data point would become a drawback for detection of multiple objects. In this paper, by analyzing limitations of the existing methods, we have devised three main processes to detect multiple salient objects. In the first stage, regional features are extracted from over-segmented regions. In the second stage, the regional features are categorized into homogeneous cluster using the mean-shift algorithm with the kernel function having various sizes. In the final stage, we compute saliency scores of the categorized regions using only spatial features without the contrast features, and then all scores are integrated for the final salient regions. In the experimental results, the scheme achieved superior detection accuracy for the SED2 and MSRA-ASD benchmarks with both a higher precision and better recall than state-of-the-art approaches. Especially, given multiple objects having different properties, our model significantly outperforms all existing models.

• International Journal of Contents
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• 제8권3호
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• pp.34-41
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• 2012

The concept of vegetation freeboard equivalence (VFE) is presented from the comparison between the rise in stage with/without vegetation and the freeboard height under design discharge conditions. In South Korea, the freeboard height of large, medium and small rivers is defined as a function of river discharge. Two models are used for this analysis of flood stage with and without vegetation: the 1-D model HEC-RAS and the 2-D model RMA-2. Both models are applied to three river study sites of the Geum River in South Korea as representative sites for a large, a medium and a small river. The analysis shows that without vegetation, both models provide comparable results and the calculated results are in very good agreement with the design configuration. The vegetation effects on the medium river are less significant, and the freeboard is adequate to contain the rise in stage from the added floodplain vegetation in large rivers. The concept of vegetation freeboard equivalence is therefore useful for the analysis of flood river stages after the restoration of channels with increased floodplain vegetation.

• Asia Marketing Journal
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• 제11권4호
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• pp.21-48
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• 2010

본 연구에서는 영화 수명 주기 상의 세 단계(개봉 당시 스크린 수, 첫 주 관객수, 전체 관객 수) 모형을 바탕으로 한국시장에서 영화의 흥행성과를 비교 분석하였다. 제작비 같은 규모(scale) 요인, 관객 평가, 전문가 비평 같은 평가(evaluation) 요인, 상영 당시의 경쟁(competition) 요인, 그리고 군집행동(herding behavior)이 각 단계에서 어떻게 다른 영향을 미치는 지 알아보았다. 또한 한국 시장에서 상영된 한국영화와 외국영화를 따로 분석함으로써 이러한 영향들이 이 두 그룹의 영화의 흥행에 어떤 차이를 보이는지를 분석하였다. 본 연구에서 군집행동(herding behavior) 현상은 국내 영화의 전체 관객 수 결정 단계에서만 유의한 것으로 나타났다. 이는 평가가 좋고 첫 주 흥행성적이 좋은 국내 영화의 경우 개봉 일주일 이후에 관객들이 현저히 늘어나는 경향이 있음을 의미한다. 각 단계에서 국내 영화와 외국 영화 간 영향요인들의 영향력 차이를 분석한 결과 규모요인은 모든 단계 모든 영화의 성과에 중요한 역할을 하지만 특히 외국영화의 첫 주 성과와 전체 성과에 결정적인 영향을 주는 것으로 나타났다. 마찬가지로 한국영화의 첫 주 성과에는 규모요인이 결정적 역할을 하였다. 경쟁요인은 모든 단계에서 외국영화보다는 국내영화에 더 중요한 영향을 미치는 것으로 나타났다. 평가요인도 한국영화의 경우 모든 단계에서 영향력이 유의했지만 특히 스크린 결정에 중요한 영향을 미치는 것으로 나타났다. 외국영화의 경우, 스크린 결정에는 평가요인의 영향이 유의하지 않았으나 전체 성과를 예측하는 데에는 중요한 역할을 하는 것으로 나타났다. 이 외에 스토리 배경 (속편여부/원작유무), 장르, 제작사 등 다른 변수들의 영향력 또한 분석되었다.

• Communications for Statistical Applications and Methods
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• 제18권4호
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• pp.423-431
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• 2011

본 논문에서는 사회적으로나 개인적으로 매우 민감한 조사에서 조사하고자 하는 모집단이 여러개의 층으로 구성되어 있는 경우에, 김종호등 (1992)이 제안한 2단계 무관질문모형에서 사용한 단순임의 추출법 대신에 층화추출법을 적용하여 각 층의 모비율에 대한 추정뿐만아니라 모집단 전체 모비율에 대한 추정을 할 수 있는 층화 2단계 무관질문모형을 제안하였다. 그리고 층화 2단계 무관질문모형을 층화 3단계 무관질문 모형으로 확장하였다. 또한, 제안한 2단계와 3단계 층화 무관질문모형들에 있어서 각 층의 표본배분에 대하여 비례배분과 최적 배분 문제를 고려하여 다루었다. 마지막으로 층화 2단계 무관질문모형과 층화 3단계 무관질문모형과의 상대효율을 비교하였으며, 그 결과 층화 3단계 무관질문모형이 층화 2단계 무관질문모형보다 효율성면에 있어서 더 우수함을 알 수 있었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.327-327
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• 2019

The study will quantify the total uncertainties in streamflow and precipitation projections for Upper Awash River Basin located in central Ethiopia. Three hydrological models (GR4J, CAT, and HBV) will be used to simulate the streamflow considering two emission scenarios, six high-resolution GCMs, and two downscaling methods. The readily available hydrometeorological data will be applied as an input to the three hydrological models and the potential evapotranspiration will be estimated using the Penman-Monteith Method. The SCE-UA algorithm implemented in PEST will be used to calibrate the three hydrological models. The total uncertainty including the incremental uncertainty at each stage (emission scenarios and model) will be presented after assessing a total of 24 (=$2{\times}6{\times}2$) high-resolution precipitation projections and 72 (=$2{\times}6{\times}2{\times}3$) streamflow projections for the study basin. Finally, the primary causes that generate uncertainties in future climate change impact assessments will be identified and a conclusion will be made based on the finding of the study.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.85-93
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• 1995

Hannan and Rissanen proposed an innovation regression method of ARMA modeling, which is composed of three stages. Its second-stage is to choose orders of the ARMA model using the BIC, which needs a lot of calculation to estimate several regression models. We are going to present a simple and efficient algorithm for the second stage using a special property of triangular Toeplitz matrices.

• 한국안전학회지
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• 제8권3호
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• pp.64-72
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• 1993

A large prropotion of structural failures are due to human error at the design stage of a structural engineering project, and many of these failures could have been prevented if there had been proper design checking. Analyses of the data from the 6 engineering firms and 24 professional engineer practitioners are shown on diagrams, also applicated for suggested models; overview checking. And then analyzed results of current work in this area, which examine the effects of error magnitude, are compared to the limit data obtained from the surveys. Overview checking only is analyzed of three typical design checking processes; self checking; Independent detailed checking, and overview checking.

• 자원ㆍ환경경제연구
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• 제22권2호
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• pp.329-365
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• 2013

본 연구의 목적은 2000-2009년 국가별로 환경과 화석에너지의 제약 하에서 경제와 환경의 효율을 측정하고자 함이다. 본 연구는 국가별 소득수준에 따른 OECD국가, 중고소득국가, 저소득국가 등 세 그룹으로 구분하여, 생산가능집합에서 바람직한 산출물인 GDP와 오염물을 동시에 포함한 '환경지향형, 경제지향형, 환경-경제지향형, Two-stage DEA모형' 등의 네 가지 방법을 제시하여 비교한다. OECD국가는 상대적으로 경제효율성이 높으나 환경효율성은 낮았고 비OECD국가는 환경효율성이 높고 경제효율성이 낮았다. 화석에너지와 온실가스의 저감의 여지는 OECD국가가 더 높았다.