• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.79-88
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• 2017

In this paper, the wind tunnel test for the measurement of aerodynamic characteristics of transmission conductors with asymmetric sections is described. A single conductor model and bundled conductor models with ice accreted shapes are tested both in steady and turbulent flow, and the aerodynamic coefficients are acquired. Transmission conductor galloping is a kind of wind-induced vibration which is characterized by primarily vertical oscillation with a very low frequency and a high amplitude. It is well known that transmission conductor galloping is generally caused by moderately strong, steady winds when a transmission conductor has an asymmetric cross-section shaped by accreted ice. Galloping should be considered from the design stage of overhead lines because it can cause severe wear and fatigue damage to attachments as well as transmission conductors. It is reported that there have been normally 20 events of galloping per year in Korea, which may be followed by serious consequences in the electric power system. Therefore, this research is performed to measure aerodynamic characteristics of ice accreted transmission conductors to understand and control transmission conductor galloping so that it would help to prevent unexpected failures and reduce the maintenance costs caused by galloping.

• Journal of Digital Convergence
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• v.15 no.2
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• pp.67-80
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• 2017

Today, Emotional Intelligence of the leader has become important in order to achieve the achievement of the organization. Especially, the automobile industry is somewhat conservative and the organizational culture of the subcontractor is still much more important than the service industry which has a flexible. In this context, I examine the Emotional Intelligence on Organizational Citizenship Behavior and Innovative Behavior in manufacture of automobile industry focusing on moderating effect of Authentic Leadership. This Study enhances the understanding of Emotional Intelligence and extends the research. Future research will needed to pioneer research methods such as various aspects of measurement and time series of various variables.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.319-325
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• 2018

The use of 3D printing (Additive Manufacturing) technology has expanded from initial model production to the mass production of parts in the industrial field based on the continuous research and development of materials and process technology. As a representative polymer material for 3D printing, the polyamide-based material, which is one of the high-strength engineering plastics, is used mainly for manufacturing parts for automobiles because of its light weight and durability. In this study, the specimens were fabricated using Selective Laser Sintering, which has excellent mechanical properties, and the flexural characteristics were analyzed according to the temperature of the two types of polyamide 12 and glass bead reinforced PA12 materials. The test specimens were prepared in the directions of $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ based on the work platform, and then subjected to a flexural test in three test temperature environments of $-25^{\circ}C$, $25^{\circ}C$, and $60^{\circ}C$. As a result, PA12 had the maximum flexural strength in the direction of $90^{\circ}$ at $-25^{\circ}C$ and $0^{\circ}$ at $25^{\circ}C$ and $60^{\circ}C$. The glass bead-reinforced PA12 exhibited maximum flexural strength values at all test temperatures in the $0^{\circ}$ fabrication direction. The tendency of the flexural strength changes of the two materials was different due to the influence of the plane direction of the lamination layer depending on the type of stress generated in the bending test.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.13 no.2
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• pp.1-13
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• 2018

This study examines the relationship between the organizational general characteristics (industry, size, location, development stage, and company age) and success factors of Korean venture firms using secondary data. Among the industries with the highest sales figures in 2016 are food / fiber / (non) metals, and the smallest category was software development. The sectors with the highest net profit were computer / semiconductor / electronic components, and the smallest category was telecommunication equipment / broadcasting equipment. The industries with the largest sales growth rate are IT / broadcasting services and software development. The industries with the highest net profit margin of sales are energy / medical / precision, and the smallest is telecommunication equipment / broadcasting equipment. In terms of the number of employees, venture firms with more than 100 employees have the largest sales and net profit, with employees between 1 and 9 have the smallest. However, these results are predictable. In general, the number of employees is highly correlated with sales and net profit. Rather, the sales growth rate and the net profit margin of sales may be meaningful. In particular, with employees between 50 ~ 99, the growth rate of sales and the net profit margin of sales were high. In terms of location, Seoul / Incheon / Gyeonggi were the regions with the highest sales and Daejeon / Sejong / Chungcheong / Gangwon were the least regions. Gwangju / Jeolla / Jeju and Seoul / Incheon / Gyeonggi were almost similar in the areas with the largest net profit. However, Daejeon / Sejong / Chungcheong / Gangwon had the lowest net profit. Unusually, the areas with the highest sales growth rate and the highest net profit margin of sales were Gwangju / Jeolla / Jeju, and the smallest areas were Busan / Jeonnam / Ulsan In the relationship between the stage of development and the performance of the company, the sales of maturity and decline stages were the highest and establishing stage was the lowest. Net profit was also the highest in mature stage and the smallest in establishing stage. The sales growth rate shows a typical pattern in the order of establishing stage, early growth stage, high growth stage, maturity stage, and decline stage. In terms of business performance, sales and net profit are the highest with 21 years or more of company age, and the smallest is less than 3 years. In addition, the sales growth rate was the highest in three years or less, and the net profit margin of sales was the highest in 4 to 10 years. This study can present lots of useful implications by suggesting integrated research model and examining the success factors of Korean venture firms and presenting the application methods of secondary data in analyzing the current status of venture industry in Korea.

• Korean Business Review
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• v.12
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• pp.29-66
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• 1999

Electronic Commerce is rapidly expanding with the development of internet and will be very useful for the consumers in the future. However, we could not find many studies on consumers' attitudes and behaviors in the cybermarket. The purpose of this study is to analyze perceptions of college students in Seoul and Chunchon on Electronic Commerce. The main findings are as follows. First, they prefer surfing on the net with search engines like Simmamai or Yahoo to directly looking over the homepages of department stores and advertisement sites. Students in Chunchon, especially, tend to check out banners at E-mail sites. Second, most of the students get information about shopping mall sites and products from their friends, newspapers or magazines. And they want to have information (advertisements) classified by brand names of the products. Third, students in Seoul rely on brand names more than those in Chunchon do. Students in Chunchon, compared with those in Seoul, believe more kinds of products are available in the internet shopping mall. They complain, however, deficiencies of information about the products and high prices. They want the price information compared with those in traditional markets. Fourth, they feel very uncomfortable about informing their credit card numbers, and thus prefer payments with Electronic Money. And finally, they are not satisfied with return and exchange policies and after-sale services. They also complain that the products are not delivered safely when they are not home. They want the delivery-date indicated.

• Journal of Engineering Education Research
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• v.9 no.3
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• pp.49-61
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• 2006

The objective of this study was to propose a new framework for the creative engineering in the product family design coursework. The idea of product family design is a good solution to fulfill customer's requirements and to respond quickly for the technology change. Mass customization based on product family and product platform is a new paradigm with variety and customization through flexibility and quick responsiveness. In this study, the subjects of product family, product platform, product family map, platform leveraging strategy, morphological matrix and module based product family design were reviewed and presented. A new idea generation scheme utilizing SCAMPER method was combined with the morphological matrix approach. For the effective product family and platform design, creative efforts and approaches were utilized and implemented in the coursework process. This will help students to develop creative thinking and approaches in the engineering problem solving.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.426-436
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• 2011

In the past, ERP had been applied to large company mainly, but recently, in order to exist from global business environment, most of smaller businesses are using or planing to introduce ERP. However, introduction of ERP requires considerable expense and effort, before ERP come into being, it is needed to measure the expense of introducing and the outcome expected. Previous analytical frameworks (according to introduction of ERP) have been focused on measuring improvement of performance by introducing ERP. This study carries out a survey on priority analysis of information system with small businesses which produce displayer parts. To derive the user's priorities which have been disregarded beside the improvement of performance on information system, this study rearranges the analysis indices by using BSC model and it analyzes the priorities of importance according to the stakeholder(manager group, middle manager group, worker group) by using ANP method.

• Journal of Korean Society of Transportation
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• v.17 no.5
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• pp.43-55
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• 1999

The value of time in freight transportation describes the importance of goods during transport and shows the direction of efficient logistic management having inventory cost in transporting The value of time differs from class to class in freight transportation. It is due to the differences of shipper's willingness to Pay for time saving. In this research the value of time in intercity freight transportation of manufacturers in Korea was estimated as follows: first, the Perception factors which were the important criteria of shippers for choosing truck were sampled. second, the shippers were classified into three homogeneous classes. third, the value of time of each class was estimated by using multinominal logit model. The results of this research showed that the value of time in freight transportation was different from every class, that the shipper had to Pay 1,680 won for saving one hour Per each shipment, and that the inventory cost in transporting occupied 9.54% in the mean freight Price.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.3
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• pp.233-238
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• 2001

This paper deals with demand forecasting of parts in an automobile model which has been extinct. It is important to estimate how much inventory of each part in the extinct model should be stocked because production lines of some parts may be replaced by new ones although there is still demands for the model. Furthermore, in some countries, there is a strong regulation that the automobile manufacturing company should provide customers with auto parts for several years whenever they are requested. The major characteristic of automobile parts demand forecasting is that there exists a close correlation between the number of running cars and the demand of each part. In this sense, the total demand of each part in a year is determined by two factors, the total number of running cars in that year and the failure rate of the part. The total number of running cars in year k can be estimated sequentially by the amount of shipped cars and proportion of discarded cars in years 1, 2,$\cdots$, i. However, it is very difficult to estimate the failure rate of each part because available inter-failure time data is not complete. The failure rate is, therefore, determined so as to minimize the mean squared error between the estimated demand and the observed demand of a part in years 1, 2,$\cdots$, i. In this paper, data obtained from a Korean automobile manufacturing company are used to illustrate our model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.194-202
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• 2019

Reliability analysis of the components frequently starts with the data that manufacturer provides. If enough failure data are collected from the field operations, the reliability should be recomputed and updated on the basis of the field failure data. However, when the failure time record for a component contains only a few observations, all statistical methodologies are limited. In this case, where the failure records for multiple number of identical components are available, a valid alternative is combining all the data from each component into one data set with enough sample size and utilizing the useful information in the censored data. The ROK Navy has been operating multiple Patrol Killer Guided missiles (PKGs) for several years. The Korea Multi-Function Control Console (KMFCC) is one of key components in PKG combat system. The maintenance record for the KMFCC contains less than ten failure observations and a censored datum. This paper proposes a Bayesian approach with a Dirichlet mixture model to estimate failure time density for KMFCC. Trends test for each component record indicated that null hypothesis, that failure occurrence is renewal process, is not rejected. Since the KMFCCs have been functioning under different operating environment, the failure time distribution may be a composition of a number of unknown distributions, i.e. a mixture distribution, rather than a single distribution. The Dirichlet mixture model was coded as probabilistic programming in Python using PyMC3. Then Markov Chain Monte Carlo (MCMC) sampling technique employed in PyMC3 probabilistically estimated the parameters' posterior distribution through the Dirichlet mixture model. The simulation results revealed that the mixture models provide superior fits to the combined data set over single models.