• Nuclear Engineering and Technology
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• 제47권4호
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• pp.461-471
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• 2015

Recently, the estimation of the social cost of energy sources has been emphasized as various novel energy options become feasible in addition to conventional ones. In particular, the social cost of introducing measures to protect power-distribution systems from power-source instability and the cost of accident-risk response for various power sources must be investigated. To account for these risk factors, an integrated societal risk assessment framework, based on power-uncertainty analysis and accident-consequence analysis, is proposed. In this study, we applied the proposed framework to nuclear power plants, solar photovoltaic systems, and wind-turbine generators. The required capacity of gas-turbine power plants to be used as backup power facilities to compensate for fluctuations in the power output from the main power source was estimated based on the performance indicators of each power source. The average individual health risk per terawatt-hours (TWh) of electricity produced by each power source was quantitatively estimated by assessing accident frequency and the consequences of specific accident scenarios based on the probabilistic risk assessment methodology. This study is expected to provide insight into integrated societal risk analysis, and can be used to estimate the social cost of various power sources.

• 제어로봇시스템학회논문지
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• 제14권9호
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• pp.931-938
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• 2008

In this paper, a novel localization algorithm robust to the unmodeled systematic odometry errors is proposed for low-cost non-holonomic mobile robots. It is well known that the most pose estimators using odometry measurements cannot avoid the performance degradation due to the dead-reckoning of systematic odometry errors. As a remedy for this problem, we tty to reflect the wheelbase error in the robot motion model as a parametric uncertainty. Applying the Krein space estimation theory for the discrete-time uncertain nonlinear motion model results in the extended robust Kalman filter. This idea comes from the fact that systematic odometry errors might be regarded as the parametric uncertainties satisfying the sum quadratic constrains (SQCs). The advantage of the proposed methodology is that it has the same recursive structure as the conventional extended Kalman filter, which makes our scheme suitable for real-time applications. Moreover, it guarantees the satisfactoty localization performance even in the presence of wheelbase uncertainty which is hard to model or estimate but often arises from real driving environments. The computer simulations will be given to demonstrate the robustness of the suggested localization algorithm.

• 전기학회논문지
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• 제64권7호
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• pp.1104-1113
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• 2015

In this paper, we propose Two-Dimensional Robust Face Recognition System Realized with the Aid of Facial Symmetry with Illumination Variation. Preprocessing process is carried out to obtain mirror image which means new image rearranged by using difference between light and shade of right and left face based on a vertical axis of original face image. After image preprocessing, high dimensional image data is transformed to low-dimensional feature data through 2-directional and 2-dimensional Principal Component Analysis (2D)2PCA, which is one of dimensional reduction techniques. Polynomial-based Radial Basis Function Neural Network pattern classifier is used for face recognition. While FCM clustering is applied in the hidden layer, connection weights are defined as a linear polynomial function. In addition, the coefficients of linear function are learned through Weighted Least Square Estimation(WLSE). The Structural as well as parametric factors of the proposed classifier are optimized by using Particle Swarm Optimization(PSO). In the experiment, Yale B data is employed in order to confirm the advantage of the proposed methodology designed in the diverse illumination variation

• Smart Structures and Systems
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• 제13권6호
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• pp.901-925
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• 2014

The reliability of a Bridge management System depends on the quality of visual inspection and the reliable estimation of bridge condition rating. However, the current practices of visual inspection have been identified with several limitations, such as: they are time-consuming, provide incomplete information, and their reliance on inspectors' experience. To overcome such limitations, this paper presents an approach of automating the prediction of condition rating for bridges based on digital image analysis. The proposed methodology encompasses image acquisition, development of 3D visualization model, image processing, and condition rating model. Under this method, scaling defect in concrete bridge components is considered as a candidate defect and the guidelines in the Ontario Structure Inspection Manual (OSIM) have been adopted for developing and testing the proposed method. The automated algorithms for scaling depth prediction and mapping of condition ratings are based on training of back propagation neural networks. The result of developed models showed better prediction capability of condition rating over the existing methods such as, Naïve Bayes Classifiers and Bagged Decision Tree.

• 유통과학연구
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• 제14권7호
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• pp.53-61
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• 2016

Purpose - The production efficiency of agricultural crops has been the subject of numerous studies in the field of agricultural economics. This study examines the production efficiency of emerging vineyards in the 14 northern U.S. states and aims to understand raw input and managerial factors affecting the grape production with focusing on the effect of farm size. Research design, data, and methodology - Using a unique survey dataset that was collected from 176 vineyards in 2012, we employed data envelopment analysis (DEA) for estimation of production efficiency in individual vineyards. Production efficiency is regressed on various input and managerial covariates to understand factors influencing the productivity. Results - Although there exists positive correlation between the farm size and productivity of vineyards in Northern U.S. states, we find negative relationship when the farm size is instrumented by the additional farm size expansion indicator. The negative effect is more pronounced for the recently established vineyards. Conclusions - This study suggests that there needs to be adequate managerial improvements for emerging vineyards in northern states for the achievement of increased productivity.

• 산경연구논집
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• 제9권7호
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• pp.33-42
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• 2018

Purpose - This paper aims to verify whether the Fisher effect and the international Fisher effect are significant between China and South Korea in the long and short run, respectively. Research design, data, and methodology - The annual and monthly data, respectively, are employed to conduct an empirical estimation under the fully modified ordinary least squares(FMOLS). The nominal interest rate is treated as an independent variable. The inflation rate is treated as a dependent variable. Results - The results exhibit whenever in the long or short run, the Fisher effect exists in China and South Korea. However, the Fisher effect in South Korea is more significant than that of in China. Meanwhile, an empirical analysis is also preformed to investigate the long-run and the short-run international Fisher effect between China and South Korea. The deviation from the equilibrium relationship is that the commodity market and the Financial market have started to integrate in China. But China's integrated level proved to be relatively lower. Conclusions - To exploit that the Fisher effect and the international Fisher effect hold between China and South Korea can help both countries deal with the sufferings from integration of the commodity market and the financial market.

• 유통과학연구
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• 제17권4호
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• pp.5-16
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• 2019

Purpose - This study examines whether price cartel firms perform downward earnings management to avoid or minimize penalty surcharges levied by the Korea Fair Trade Commission and analyzes such earnings management in distribution industry. Research design, data, and methodology - We use 247 firms from 64 price cartel cases in the period of 2011-2016, and collect data from 3 years before to 3 years after the start of price cartel. Earnings management is measured by discretionary accruals. Three discretionary accrual estimation models are employed; modified Jones model, ROA adjusted modified Jones model and CFO-adjusted modified Jones model. For pre- and post-cartel periods, one year, two year, and three year windows are used. Additional empirical analyses are performed for distribution industry sub-sample of 25 cartel firms. Result - The regression results show that cartel firms' discretionary accruals are significantly lower in the period after the start of price cartel than before. And discretionary accruals are lower in cartel firms than in non-cartel firms during the cartel period. Cartel firms in distribution industry also show the earnings management similar to those in other industries. Conclusions - These two findings lead to the conjecture that managers of cartel firms manage their earnings downward. This behavior is indistinguishable between firms in distribution industry and other industries.

• Asian Journal of Business Environment
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• 제10권4호
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• pp.21-27
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• 2020

Purpose: The present study examines the effects of tourism on carbon dioxide emissions for selected South Asian economies over the time from 1995 to 2016. Research design, data and methodology: The present study is an annual time series analysis of tourism and CO2 emissions. The data is taken from World Development Indicators, an official data bank of World Bank. The study sample covers four South Asian countries, namely Bangladesh, India, Pakistan, Sri Lanka and Nepal. The empirical analysis is conducted by employing Pedroni panel cointegration, Fully Modified OLS, and Dynamic OLS approaches of estimation. Results: Tourism significantly increases environmental degradation in selected South Asian economies. The empirical estimated results indicate, that 1 % increase in tourism related activities leads to 0.16 % increase in CO2 emissions. In addition energy consumption and GDP are also causing an upsurge in CO2 emissions in the selected panel of South Asian economies. As the empirical results indicate that 1% increase in GDP stimulates carbon dioxide emissions by 0.23%. Conclusion: In order to protect the environment, the study emphasizes that sustainable tourism practices need to be promoted in the selected South Asian countries. Policy implication and provided and discussed.

• 유통과학연구
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• 제18권10호
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• pp.65-75
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• 2020

Purpose: This study aims to examine how to review contents of experiential and utilitarian products (e.g., skincare products) and how to affect review helpfulness by applying natural language processing techniques. Research design, data, and methodology: This study uses 69,633 online reviews generated for the products registered at Amazon.com by 13 Korean cosmetic firms. The authors identify key topics that emerge about consumers' use of skincare products such as skin type and skin trouble, by applying bigram analysis. The review content variables are included in the review helpfulness model, including other important determinants. Results: The estimation results support the positive effect of review extremity and content on the helpfulness. In particular, the reviewer's skin type information was recognized as highly useful when presented together as a basis for high-rated reviews. Moreover, the content related to skin issues positively affects review helpfulness. Conclusions: The positive relationship between extreme reviews and helpfulness of reviews challenges the findings from prior literature. This result implies that an in-depth study of the effect of product types on review helpfulness is needed. Furthermore, a positive effect of review content on helpfulness suggests that applying big data analytics can provide meaningful customer insights in the online retail industry.

• 한국대기환경학회지
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• 제22권2호
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• pp.167-177
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• 2006

In this study, a fundamental work for developing a biogenic Volatile Organic Compounds(BVOC) emission model in Korea has been carried out. Two different approaches, Biogenic Emission Inventory System(BEIS2) and CORINAIR Methodology(CORINAIR) were compared for estimating BVOC emissions. It was found that BEIS and CORINAIR showed very similar results each other BVOC emissions estimated by two different methods were about the same on a national and regional(provincial) scale. In case of monthly emissions the difference between BEIS and CORINAIR were larger than those on a national and regional(provincial) scale, especially in summer season(June, July and August). Although BEIS and CORINAIR are quite different techniques to correct the environmental conditions, they revealed similar results. Therefore, it is proven that both the methods are able to be applied to the estimation of the BVOC emissions in Korea.