• Wind and Structures
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• v.26 no.6
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• pp.383-395
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• 2018

An accurate determination of wind speed distribution is the basis for an evaluation of the wind energy potential required to design a wind turbine, so it is important to estimate unknown parameters of wind speed distribution. In this paper, Gumbel distribution is used in modelling wind speed data, and alternative robust estimation methods to estimate its parameters are considered. The methodologies used to obtain the estimators of the parameters are least absolute deviation, weighted least absolute deviation, median/MAD and least median of squares. The performances of the estimators are compared with traditional estimation methods (i.e., maximum likelihood and least squares) according to bias, mean square deviation and total mean square deviation criteria using a Monte-Carlo simulation study for the data with and without outliers. The simulation results show that least median of squares and median/MAD estimators are more efficient than others for data with outliers in many cases. However, median/MAD estimator is not consistent for location parameter of Gumbel distribution in all cases. In real data application, it is firstly demonstrated that Gumbel distribution fits the daily mean wind speed data well and is also better one to model the data than Weibull distribution with respect to the root mean square error and coefficient of determination criteria. Next, the wind data modified by outliers is analysed to show the performance of the proposed estimators by using numerical and graphical methods.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.40-49
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• 2009

Recently, many methodologies and development environment to shorten embedded system development time and to satisfy customer requirement were proposed. In this paper, a method to shorten development time by improving cross development environment is proposed for embedded system development, This method was designed and implemented just for the environment using virtual prototyping development tools and embedded development kit. According to implementation and result analysis, the proposed method show the better performance the than existing method in the cross development environment which is required to modify more than once.

• Journal of Distribution Science
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• v.13 no.2
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• pp.35-44
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• 2015

Purpose - In this study, corporate social responsibility activities as perceived by customers visiting super-centers and the influence of the authenticity of such social responsibility activities on trust have been examined while attempting to verify how trust would influence consumers' attitude and purchase intention. Research design, data, and methodology - For data collection, a questionnaire survey has been conducted on 200 consumers who would visit super-centers, and 161 effective samples have been used for the final analysis. Methodologies such as Cronbach's α, factor analysis, correlation analysis, and structural equation modeling were used. Results - Among corporate social responsibility activities, legal responsibility in particular has turned out to influence consumers rather greatly. Thus, law observance has turned out to be a necessity rather than merely an economic or ethical responsibility; as for trust, trust in the product has turned out to exert more influence on consumers than trust in the enterprise. Conclusions - Corporate social responsibility activities can mean that the complete fulfillment of natural and proper corporate responsibility will secure consumer trust, thus influencing consumer attitude and purchase intention positively.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.402-407
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• 2004

Since the world wide web, simple and convenient tool, has proposed, the Internet became the most simple network resource which provide many informations of the world. Furthermore, various methodologies are developed to support the dynamic service such as 3D View web service. We will propose the volume rendering view program that interactively visualize the 3D data on the web. The 3D Data is obtained by stacking the 2D images along the z-direction. We also employ the COM based OCX control which is a kind of Active component. This web program will contribute the diagnosis of the diseases through the 3D visualization and image analysis functions at remote places.

• Asian Journal of Business Environment
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• v.4 no.1
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• pp.15-23
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• 2014

Purpose - In this study, we inspected the effects of public-service advertising (PSA) and commercial advertisements on consumers' social and emotional values. Specifically, we include source credibility on advertising models as a mediating variable to compare the path difference between the social and emotional value of consumers, and to test the appropriateness of advertising expenses. Research design, data, and methodology - A total of 219 copies of effective questionnaires were used and methodologies such as Cronbach's alpha, paired samples t-test, and structural equation modeling (SEM) were conducted. Results - The results showed that the consumer model was effective at PSA, while celebrities and CEOs were effective at commercial advertising. Further, only credibility (among source credibility) made a significant difference in the test of PSA models of both PSA and commercial advertising that consumers preferred. Conclusions - The advertising model types varied depending on advertising types (for example, PSA and commercial advertising). Therefore, celebrities and CEOs appearing in commercial advertising should have no ethical or moral defect by self-control, and marketers should elect the model considering such a fact.

• The Journal of Asian Finance, Economics and Business
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• v.5 no.3
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• pp.81-93
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• 2018

This study developed and tested the impact of hallyu 4.0, social media, and consumer ethnocentrism on the decision to purchase Korean products of Generation C in Vietnam. Both qualitative and quantitative methodologies were utilized in this study. Qualitative research was first carried out with in-depth interview, conducted to derive measurement items for the interested constructs. Quantitative research used cross-sectional field design by pilot study and official study. The model was tested and developed using data collected by questionnaires, from a sample of 575 respondents, by both electronic and paper surveys with non-probability and convenience sampling techniques. SPSS 20 and AMOS 20 software were employed to analyze the data. The results of structural equation modeling showed that hallyu 4.0, social media, and consumer ethnocentrism influenced the intermediates variables: subject norms, trust, attitude and behavioral intention and influenced purchase decision. The hallyu 4.0, social media, and consumer ethnocentrism are independent variables. They impact purchase decision through mediating variables such as trust, subjective norms, attitude and behavioral intention. Social media influences not only to trust but also to subjective norms. Subjective norms influence on purchase decision. This study also discovers an interesting fact that trust and attitude variables have an impact on behavioral intention and purchase decision.

• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.123-130
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• 2015

Wolsong Unit 2,3&4 has been performing a containment integrity test during power operation. This test could impact to the safe operation during test. If an accident occurs during pressure dropping phase, reactor trip can be delayed because of the increased pressure difference which causes a time delay to reach the trip set-point. On the contrary, if an accident occurs during pressure increasing phase, reactor trip could be accelerated because the pressure difference to the trip set-point decrease. Point Lepreau nuclear power plant, which installed GCLMS (Gross Containment Leakage Monitoring System) in 1990, has discontinued the test since 1992 due to these adverse effects. Therefore, we evaluated the risk to obviate the GCLMS test based on PWR's ILRT (Integrated Leak Rate Test) extension methodologies. The results demonstrate that risk increase rate is not high in case of performing only ILRT test at every 5 years instead of doing GCLMS test at every 1.5 years. In addition, the result shows that GCLMS test can be removed on a risk-informed perspective since risk increasement is in acceptable area of regulatory acceptance criteria.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.231-234
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• 2007

This study proposes a Web GUI system using MGIS-based three-dimensional data models and hydrodynamic model. The study of Web GUI (Graphic User Information) system based on the MGIS (Marine Geographic Information System) is mainly performed on effective methodologies which transform real world data to computing world data. Finally, we design a Seomjin River Estuary Web GUI system integrating above data models. It must adds more ecological information and the various service item for approach more easily in order to user.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1100-1108
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• 2014

Modular multilevel converters (MMCs) have emerged as the most promising topology for high and medium voltage applications for the coming years. However, one particular negative characteristic of MMCs is the existence of circulating current, which contains a dc component and a series of low-frequency even-order ac harmonics. If not suppressed, these ac harmonics will distort the arm currents, increase the power loses, and cause higher current stresses on the semiconductor devices. Repetitive control (RC) is well known due to its distinctive capabilities in tracking periodic signals and eliminating periodic errors. In this paper, a novel circulating current control scheme base on RC is proposed to effectively track the dc component and to restrain the low-frequency ac harmonics. The integrating function is inherently embedded in the RC controller. Therefore, the proposed circulating current control only parallels the RC controller with a proportional controller. Thus, conflicts between the RC controller and the traditional proportional integral (PI) controller can be avoided. The design methodologies of the RC controller and a stability analysis are also introduced. The validity of the proposed circulating current control approach has been verified by simulation and experimental results based on a three-phase MMC downscaled prototype.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2083-2090
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• 2000

In order to manage nuclear power plants safely and cost effectively, it is necessary to develop integrity evaluation methodologies for the main components. Recently, the integrity evaluation techniques were broadly studied regarding the license renewal of nuclear power plants which were approaching their design lives. Since the integrity evaluation process requires special knowledges and complicated calculation procedures, it has been allowed only to experts in the specified area. In this paper, an integrity evaluation system for reactor pressure vessel was developed. RVIES(Reactor Vessel Integrity Evaluation System) provides four specific integrity evaluation procedures covering PTS(Pressurized Thermal Shock) analysis, P-T(Pressure-Temperature) limit curve generation, USE(Upper Shelf Energy) analysis and Fatigue analysis. Each module was verified by comparing with published results.