• 한국건설관리학회논문집
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• 제10권4호
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• pp.3-13
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• 2009

BTL 사업 추진 시 협상단계는 시설, 운영, 재무분야 등 성과요구수준서의 준수 및 반영여부를 겸토하고 그 수위를 확정하여 실시협약에 이르게 하는 단계로써 사업추진 전 과정에서 차지하는 비중과 중요성이 매우 높다고 할 수 있다. 그러나 국내 BTL사업 추진 시 협상에 관한 일관적 지표나 협상 후 성과를 측정하기 위한 표준화된 지표가 기준이 제시되어 있지 않아 시간적 낭비요인의 발생과 더불어, 기술 및 품질 가격 등 협상수위 및 결과에 대한 평가가 모호한 실정이다. 이에 본 연구에서는 협상 후 성과를 객관적으로 평가 검증하기 위한 방안 제시의 일환으로 VE(가치공학)기반 협상수행 성과평가 절차 및 지표를 제시하고자 하였다. 이를 위하여 문화시설 BTL사업을 대상으로 협상 시 고려해야 하는 항목을 6영역, 38분야, 135항목으로 분류하고 가중치를 분석하여 정량화된 평가 지표를 구축하였고, 이를 바탕으로 협상성과를 측정할 수 있는 지표을 제시하였다. 본 연구의 결과는 협상참여자에게 BTL사업 협상 전 중점 검토사항의 파악과 협상 중 피드백의 지표 및 협상 후 성과평가의 척도가 될 수 있을 것으로 판단된다.

• International Journal of Ocean System Engineering
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• 제2권4호
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• pp.233-238
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• 2012

In this study, we carried out a precedent investigation for an ultra-large container ship, which is expected to be a higher value-added vessel. We studied a preliminary optimized design technique for estimating the principal dimensions of an ultra-large container ship. Above all, we have developed optimized dimension estimation models to reduce the building costs and weight, using previous container ships in shipbuilding yards. We also applied a generalized estimation model to estimate the shipping service costs. A Genetic Algorithm, which utilized the RFR (required freight rate) of a container ship as a fitness value, was used in the optimization technique. We could handle uncertainties in the shipping service environment using a Monte-Carlo simulation. We used several processes to verify the estimated dimensions of an ultra-large container ship. We roughly determined the general arrangement of an ultra-large container ship up to 1500 TEU, the capacity check of loading containers, the weight estimation, and so on. Through these processes, we evaluated the possibility for the practical application of the preliminary design model.

• 한국국방경영분석학회지
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• 제27권1호
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• pp.10-27
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• 2001

This paper deals with the application of PRICE model in estimating the proper acquisition cost for weapon budgeting phase. The PRICE(Parametric Review of Information for Costing and Evaluation) Hardware model is a computerized method for deriving cost estimates of electronic and mechanical hardware assemblies and systems. The model can be used in obtaining not only initial cost estimates in conceptual phase, but also detailed cost estimates in budgeting phase depending on available historical and empirical data. We analyzed first step cost estimate parameters and derived cost equations using PRICe output dta. Using weight and complexity, We can find cost variation. Sensitivity analysis shows that cost increases exponentially as complexity increases exponentially as complexity increases. We estimated KAAV\`s (Korea Amphibious Assault Vehicle) production cost using the PRICE model and compare with engineering cost estimates which is based on actual production data submitted by the production company. The result shows that tow estimates are close within $\pm2%$ differences.

• 대한토목학회논문집
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• 제33권4호
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• pp.1693-1705
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• 2013

국내의 수로교는 쌀문화로 상징되는 농업용수를 공급하는 교량으로서 수로교를 개보수하기 위해서는 기본설계를 실시하는 것이 바람직하나 현재 생략되고 있는 실정이므로 이에 소요되는 공사비를 산정할 필요가 있다. 이 연구에서는 2003년 이후 교체한 RC구조 수로교에 대한 실적자료를 기초로 개략공사비 산정 회귀분석(RA) 모델과 사례기반추론(CBR) 모델을 개발하였다. RA 모델의 경우 단순회귀 모델이 다중회귀 모델보다 오차율이 낮았다. CBR 모델의 경우 유전 알고리즘을 이용하였으며 영향요인의 가중치, 편차, 순위조건을 최적화 대상으로 하였고 특히 영향요인 가중치의 범위를 제한하여 수로교 개보수 공사비의 예측 정확도를 제고하였다. RA 모델과 CBR 모델 사이의 오차율은 통계적 차이를 보이지 않았다. 본 논문에서 제시된 수로교 개보수 개략공사비 산정방법은 개보수사업의 시행에 따른 신속한 의사결정을 하는데 활용될 수 있을 것으로 기대된다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권2호
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• pp.149-154
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• 2000

The objectives of this study of Hanwoo (Korean Cattle) were 1) to estimate genetic parameters for direct and maternal genetic effects for birth weight, weaning weight, and six months weight which can be used for genetic evaluations and 2) to compare models with and without grandmatemal effects. Data were obtained from the National Livestock Research Institute in Rural Development Administration (RDA) of Korea and were used to estimate genetic parameters for birth weight (BW, n=10,889), weaning weight at 120-d (WW, n=8,637), and six month weight (W6, n=8,478) in Hanwoo. Total number of animals in pedigrees was 14,949. A single-trait animal model was initially used to obtain starting values for multiple-trait animal models. Estimates of genetic parameters were obtained with MTDFREML using animal models and derivative-free REML (Boldman et al., 1995). Estimates of direct heritability for BW, WW, and W6 analyzed as single-traits were 0.09, 0.03, and 0.02 from Model 3 which included direct and maternal genetic, maternal permanental environmental effects, and effects due to sire ${\times}$ region ${\times}$ year-season interaction, respectively. Ignoring sire ${\times}$ region ${\times}$ year-season interaction effect in the model (Model 2) resulted in larger estimates for direct heritability than for Model 3. Estimates of maternal heritability for BW, WW and W6 were 0.04, 0.05, and 0.07 from Model 3, respectively. The estimates of direct-maternal genetic correlation were positive for BW, WW, and W6 with Model 3 but were negative with Model 2 for WW and W6. Estimates of direct genetic correlations between BW and WW, BW and W6, and WW and W6 were large: 0.52, 0.45, and 0.90, respectively. Genetic correlations were also large and positive for maternal effects for BW with maternal effects for WW and W6 (0.69 and 0.74), and even larger for WW with W6 (0.97). The log likelihood values were the same for models including grandmatemal effects as for models including maternal effects for all traits. These results indicate that grandmatemal effects are not important for these traits for Hanwoo or that the data structure was not adequate for estimating parameters for a grandmatemal model.

• 한국토양비료학회지
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• 제50권5호
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• pp.409-421
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• 2017

Recently Unmanned Aerial Vehicle (UAV) technology offers new opportunities for assessing crop growth condition using UAV imagery. The objective of this study was to select optimal vegetation indices and regression model for estimating of rice growth using UAV images. This study was conducted using a fixed-wing UAV (Model : Ebee) with Cannon S110 and Cannon IXUS camera during farming season in 2016 on the experiment field of National Institute of Crop Science. Before heading stage of rice, there were strong relationships between rice growth parameters (plant height, dry weight and LAI (Leaf Area Index)) and NDVI (Normalized Difference Vegetation Index) using natural exponential function ($R{\geq}0.97$). After heading stage, there were strong relationships between rice dry weight and NDVI, gNDVI (green NDVI), RVI (Ratio Vegetation Index), CI-G (Chlorophyll Index-Green) using quadratic function ($R{\leq}-0.98$). There were no apparent relationships between rice growth parameters and vegetation indices using only Red-Green-Blue band images.

• 한국축산식품학회지
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• 제28권2호
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• pp.187-195
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• 2008

The purpose of this study was to establish proper shipping weight and backfat thickness by applying the growth model to backfat thickness, measured by means of not only body weight, but also ultrasonography, and predicting the changes by age. Three breeds, i.e. Duroc, Landrace, and Yorkshie, were analyzed, and the Gompertz, logistic, and Von Bertalanffy model were used for inference with the parameter of the growth model being sex. As a result, both body weight and backfat thickness showed different growth curve parameters and characteristics at inflection points depending on model selection and sex. As for backfat thickness, in estimating the inflection point, unlike the case of body weight, the inflection ages of the boars of the Duroc breed was earlier than that of sows, whereas the inflection ages of the sows of the Landrace and Yorkshire breeds was earlier than that of boars. More than anything else, in the analysis of the changes in backfat thickness according to body weight, as the body weight reached 145kg, the backfat thickness showed much variation as great as 1.7-3.2 cm in each breed and sex. In addition, unlike the other breeds, the boars of the Landrace breed showed an exponential type of relationship between body weight and backfat thickness. As they grow to become 100 kg or heavier, abrupt change in back fat thickness was confirmed. If the growth of body weight and backfat thickness is understood and the genetic relationship is taken advantage of like this, it would be possible to set desired body weight and backfat thickness, and thus help effectively set the shipping time. If not only the phenotype, but also genetic parameters about growth characteristics are estimated and analyzed additionally, more effective data can be generated.

• 한국농림기상학회지
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• 제20권2호
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• pp.205-213
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• 2018

작물 모델의 개발과 검증에 사용되는 생체중 자료는 파괴적 샘플링을 통해 얻어져 왔다. 파괴적 샘플링이 가지는 단점을 보완하기 위해 저가형 3D 센서인 Kinect 센서와 무료 공개 소프트웨어들을 사용하여 생체중을 추정하는 기법을 개발하였다. 특히, 많은 작물모델들이 개발되어 있지 않은 배추를 대상으로 입체이미지를 생성하여, 그로부터 얻어진 부피와 생체중 추정치의 신뢰도를 분석하고자 하였다. 크기가 다른 배추 결구 부위를 스캔하기 위해 Kinect 센서와, Microsoft가 무상으로 제공하는 Software Development Kit 내 Kinect Fusion Explorer 프로그램을 사용하였다. 개별 배추의 입체이미지를 생성하기 위해 3D 그래픽 편집 소프트웨어인 Meshlab을 활용하여 배경과 불필요한 물체를 수동으로 제거하였다. 또한, 불완전한 입체모델로부터 생체중 추정을 위해 3D 프린터 소프트웨어인 Makerbot Desktop 을 사용하여 배추를 생성하기 위해 필요한 플라스틱 필라멘트 소모량을 추정하였다. 입체모델 편집 프로그램인 Blender를 사용하여 부피를 추정하였을 때, 실제 부피에 비해 17.6%에서 2160.6% 범위의 상당한 오차가 있었다. 반면, 필라멘트 소요량은 실제 배추 생체중 변이의 98.7%를 설명할 수 있었다. 또한, 이들의 상관관계는 5% 수준에서 유의하였다. 이러한 결과들은 직접적인 부피 계산 절차를 제외하더라도 간편하게 생체중을 추정할 수 있음을 확인하였다. Kinect 센서를 사용하여 배추의 생체중 추정이 가능하다는 것이 확인 되었으나, 기존의 고가형 3D 센서에 비해 낮은 해상도와 주간에 활용이 어려운 점이 있다. 그럼에도 불구하고, 배추 생육 모델의 시계열적 검증 자료를 Kinect 센서를 이용하여 간편하고 신속하게 획득할 수 있어 모델의 불확도를 감소하는 데에 기여할 수 있을 것으로 판단된다. 따라서, 후속 연구에서 보다 저렴한 가격대의 3D 센서들을 대상으로 야외 및 주간조건애서 작물의 생체중 측정 가능성에 대해 검토하고 작물 모형 개발 및 개선을 위한 기술개발이 이루어져야 할 것으로 사료된다.

• Structural Engineering and Mechanics
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• 제38권5호
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• pp.651-674
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• 2011

This paper presents a novel method for predicting the failure probability of structural or mechanical systems subjected to random loads and material properties involving multiple design points. The method involves Multicut High Dimensional Model Representation (Multicut-HDMR) technique in conjunction with moving least squares to approximate the original implicit limit state/performance function with an explicit function. Depending on the order chosen sometimes truncated Cut-HDMR expansion is unable to approximate the original implicit limit state/performance function when multiple design points exist on the limit state/performance function or when the problem domain is large. Multicut-HDMR addresses this problem by using multiple reference points to improve accuracy of the approximate limit state/performance function. Numerical examples show the accuracy and efficiency of the proposed approach in estimating the failure probability.

• Journal of Welding and Joining
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• 제18권5호
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• pp.33-40
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• 2000

Fatigue crack propagation life of weld toe crack through residual stress field was estimated with Elber's crack concept. Propagation of weld toe crack is heavily influenced by residual stress caused by welding process, so it is essential to take into account the effect of residual stress on the propagation life of weld toe crack. Fatigue crack at transverse and longitudinal weld toe was studied respectively, which represent typical weld joint in ship structure. Numerical and experimental studies are performed for both cases. Residual stress near weldment was estimated through nonlinear thermo-elasto-plastic finite element method, and residual stress intensity factor with Glinka's weight function method. Effective stress intensity factor was calculated with Newman-Forman-de Koning-Henriksen equation which is based on Dugdale strip yield model in estimating crack closure level U at different stress ratio. Calculated crack propagation life coincided well with experimental results.