• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 춘계 학술대회논문집
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• pp.142-147
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• 2005

A numerical study of evaluation of turbulence models for thermal striping phenomenon is performed. The turbulence models chosen in the present study are the two-layer model, the shear stress transport (SST) model and the V2-f model. These three models are applied to the analysis of the triple jet flow with the same velocity but different temperature. The unsteady Reynolds-averaged Navier-Stokes (URANS) equation method is used together with the SIMPLE algorithm. The results of the present study show that the temporal oscillation of temperature is predicted only by the V2-f model, and the accuracy of the mean velocity, the turbulent shear stress and the mean temperature is a little dependent on the turbulence model used. The the two-layer model and the SST model shows nearly the same capability of predicting the thermal striping and the amplitude of the temperature fluctuation is predicted best by the V2-f model.

• 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.

• 한국컴퓨터정보학회논문지
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• 제4권4호
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• pp.226-235
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• 1999

본 연구에서는 전자상거래시스템 공급자의 평가와 선정을 위한 모형을 구축하였다. 기업의 의사결정과 정은 여러 상충하는 목적들을 동시에 고려하는 경우가 대부분이기 때문에 이러한 상황에 적합한 다목표 지향적인 수리모형 구축의 필요성이 제시되었다. 또한 제공되는 데이터의 불명확성과 여러 목적들을 동시에 고려할 경우 발생할 수 있는 의사결정자의 열망수준과 그 만족정도를 반영하기 위해 본 연구에서는 3유형의 다목적계획모형을 제시하였다. 최소연산자 모형, 가중치 다목적계획모형 및 선제우선순위 다목적계획모형의 구축 후. 가상기업에 대한 설례를 통해 그 적용가능성을 알아보았다.

• 대한안전경영과학회지
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• 제9권1호
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• pp.145-156
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• 2007

This paper is to propose model classification and evaluation of measurement uncertainty. In order to obtain type A and B uncertainty, variety of measurement mathematical models are illustrated by example. The four steps to evaluate expanded uncertainty are indicated as following; First, to get type A standard uncertainty, measurement mathematical models of single, double, multiple, design of experiment and serial autocorrelation are shown. Second, to solve type B standard uncertainty measurement mathematical models of empirical probability distributions and multivariate are presented. Third, type A and B combined uncertainty, considering sensitivity coefficient, linearity and correlation are discussed. Lastly, expanded uncertainty, considering degree of freedom for type A, B uncertainty and coverage factor are presented with uncertainty budget. SPC control chart to control expanded uncertainty is shown.

• 로봇학회논문지
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• 제14권2호
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• pp.114-121
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• 2019

This paper presents a new benchmark system for visual odometry (VO) and monocular depth estimation (MDE). As deep learning has become a key technology in computer vision, many researchers are trying to apply deep learning to VO and MDE. Just a couple of years ago, they were independently studied in a supervised way, but now they are coupled and trained together in an unsupervised way. However, before designing fancy models and losses, we have to customize datasets to use them for training and testing. After training, the model has to be compared with the existing models, which is also a huge burden. The benchmark provides input dataset ready-to-use for VO and MDE research in 'tfrecords' format and output dataset that includes model checkpoints and inference results of the existing models. It also provides various tools for data formatting, training, and evaluation. In the experiments, the exsiting models were evaluated to verify their performances presented in the corresponding papers and we found that the evaluation result is inferior to the presented performances.

• Journal of information and communication convergence engineering
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• 제21권1호
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• pp.82-89
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• 2023

Various machine-learning models may yield high predictive power for massive time series for time series prediction. However, these models are prone to instability in terms of computational cost because of the high dimensionality of the feature space and nonoptimized hyperparameter settings. Considering the potential risk that model training with a high-dimensional feature set can be time-consuming, we evaluate a feature-importance-based feature selection method to derive a tradeoff between predictive power and computational cost for time series prediction. We used two machine learning techniques for performance evaluation to generate prediction models from a retail sales dataset. First, we ranked the features using impurity- and Local Interpretable Model-agnostic Explanations (LIME) -based feature importance measures in the prediction models. Then, the recursive feature elimination method was applied to eliminate unimportant features sequentially. Consequently, we obtained a subset of features that could lead to reduced model training time while preserving acceptable model performance.

• 한국통신학회논문지
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• 제33권5B호
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• pp.364-378
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• 2008

Data Envelopment Analysis(DEA) 모형은 다수출력/다수입력을 갖는 IT중소기업 정부자금지원정책 성과평가에 활용가능하다. DEA효율성지수의 정확성 제고를 위해 기업역량을 반영한 외생고정변수를 DEA모형에서 고려할 수 있다. 또한, 다수 DEA기본모형과 확장모형을 활용한 성과평가를 시도함으로써, 단일 DEA모형에 의존하는 성과평가의 한계를 완화할 수 있다. 본 연구는, IT중소기업 정부자금지원시점에서의 기업자산, 매출액, 종업원수를 외생고정변수로 갖는; 1)DEA자료구조 정립; 2)DEA기본모형과 확장모형 수립; 3)실증자료를 이용한 사례분석을 예시한다. DEA기본모형으로 CCR, BCC, Super-efficiency모형, DEA확장모형으로 비제어변수(noncontrollable variables), 비자유변수(nondiscretionary variables)를 갖는 모형을 수립한다. DEA모형 비교 및 Analytic Hierarchy Process(AHP) 가중치를 이용한 통합 활용절차가 설명된다. 모수 비모수분산분석에 의한 기술분야별 DEA효율성지수로써의 성과유의차를 판정한다.

• 한국군사과학기술학회지
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• 제19권1호
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• pp.57-65
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• 2016

Threat evaluation is a process to estimate the threat score which enemy aerial threat poses to defended assets. The objective of threat evaluation is concerned with making an engagement priority list for optimal weapon allocation. Traditionally, the threat evaluation of massive air threats has been carried out by air defence experts, but the human decision making is less effective in real aerial attack situations with massive enemy fighters. Therefore, automation to enhance the speed and efficiency of the human operation is required. The automatic threat evaluation by air defense experts who will perform multi-variable judgment needs formal models to accurately quantify their linguistic evaluation of threat level. In this paper we propose a threat evaluation model by using a fuzzy rule-based inference method. Fuzzy inference is an appropriate method for quantifying threat level and integrating various threat attribute information. The performance of the model has been tested with a simulation that reflected real air threat situation and it has been verified that the proposed model was better than two conventional threat evaluation models.

• International Journal of Contents
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• 제8권2호
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• pp.67-74
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• 2012

Technological substitution is the process by which a radical technology replaces the dominant technology in an industry. The processes of diffusion and substitution have been modeled extensively (Technology & innovation, 2010). However, the formulation of classical quantitative models encompasses only part of the theoretical space. These models impose many simplified constraints to the achievement of analytical resolution. The interior design organization needs to establish a set of technical system requirements by describing the scope of the accessibility needs of the organization against current technology use. Because of complicated design resources and ongoing advances in design technologies, design systems face the challenge of prioritizing new technologies for supporting. The problem is small design organization administration often displays a lack of concern toward the evaluation of technology integration. In this paper, I will identify the influence of a design organization's technology, and predict how future technology will inform, support, and potentially hinder productivity, culture, and work satisfaction within a design organization in the industry. In addition, I will use current design organizational behavior and leadership models to support my predictions. Finally, I will examine a proven approach to assist designers with evaluating technology integration in interior design organization. The goal is to develop a high quality, professional development scorecards for the evaluation. I will conduct both the evaluation of technology integration and CRM performance evaluation is recommended to assess the effectiveness of technology integration. Therefore, the evaluation of integration technologies oriented design hold the promise of solving the organization application integration challenge. The evaluation of integration technology is a significant pattern for processing such a vision. The careful selection of an integration technology for this purpose is crucial in contributing toward the success of such an interior design organization endeavor.

• 디지털융복합연구
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• 제19권6호
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• pp.113-132
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• 2021

특허수명은 특허가치를 평가하는 척도로 사용되어 왔다. 본 연구에서는 특허수명을 예측하여 개별특허의 가치를 평가함에 있어, 특허의 내적가치요소와 외적가치요소를 하나의 모델로 평가하기 위하여 화학반응속도 추정식으로 널리 알려진 아레니우스식을 사용한 새로운 평가모델을 제시하였다. 한국의 소멸된 특허데이터를 활용하여 평가모델의 성능을 검증하였으며, 선행연구에서 특허평가모델로 사용되었던 SVM, Logistic reg., ANN 모델과 성능을 비교하였다. 결과적으로, 제안한 평가모델이 다른 모델 보다 정확도가 높았으며, 특허권자의 특성을 고려한 상대체감비용지수 반영 시 여러 평가모델에서 정확도가 상승하는 경향을 보였다. 또한, 특허의 예측수명등급과 특허의 실제수명과는 강한 상관관계가 있었다. 이러한 평가모델은 대량의 특허를 객관적으로 신속하게 평가할 수 있으며 특허의 유지여부에 대한 의사결정 혹은 기술거래나 평가에 활용할 수 있다. 특히, 평가목적에 따라 특허만을 평가하거나 사업화주체나 기술적 특성을 고려한 평가가 필요한 경우에 각각 사용될 수 있다.