• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2000-2007
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• 2016

Generally, in order to implement the CRM(Critical Conduction Mode), the analog controller is used rather than a digital controller because the control is simple and uses less power. However, according to the semiconductor technology development and various user needs, digital control system based on a DSP is on the rise. Therefore, in this paper, the CRM bridgeless PFC converter based on a digital control is proposed. It is necessary to detect the inductor current when it reaches zero and peak value, for calculating the on time and off time by using the current information. However, in this paper, the on-time and off-time are calculated by using the proposed algorithm without any current information. If the switching-times are calculated through the steady-state analysis of the converter, they do not reflect transient status such as starting-up. Therefore, the calculated frequency is out of range, and the transient current is generated. In order to solve these problems, limitation method of the on-time and off-time is used, and the limitation values are varied according to the voltage reference. In addition, in steady state, depending on the switching frequency, the inductance is varied because of the resonance between the inductor and the parasitic capacitance of the switching elements. In order to solve the problem, inductance are measured depending on the switching frequency. The measured inductance are used to calculate the switching time for preventing the transient current. Simulation and experimental results are presented to verify the proposed method.

• Journal of the Korean Institute of Educational Facilities
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• v.24 no.6
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• pp.37-44
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• 2017

This study is about user satisfaction of the Junior College Library based on its characteristics of space composition. For this, we studied characteristics of space composition targeting the libraries in colleges in Seoul and Gyeonggi-do. First, in case of study of characteristics of space composition for books and library data, student satisfaction for traditional and normal library areas was high. It means that the service based on library areas should start from normal library areas as well as there is a change about space as the type of data in libraries change to electric data and multimedia. Second, If we look at the space for a reader and a user, satisfaction for a normal reading room was high. we can also see that satisfaction for a computer room and a multimedia reading room was not higher but still high. Also, the reason why satisfaction for a multimedia reading room that provides various activities was high was that the complex of a library space is needed to provide users with various activities. Third, in case of space for programme function and meeting, satisfaction for the room of video information and the group study room was high. we can see that user satisfaction for the space got high basically when a user is satisfied with the proper information technology based on interaction Fourth, as a result of variance analysis of 3 spaces of Junior College Library and the services, the size of the space of service does not influence user satisfaction directly. Even the space is small, if it decorates variously like with a lighting for a user, a window seat to meet the nature of users and has specific factors such as space reservation using internet, user satisfaction is high. If we summarise the result of this study, to make user satisfaction for speace in a Junior College Library higher, not just we need to try to make it extend as a educational, a cultural place but we also need to accept the student's requirement that the space also needs to be extend as a complex cultural space.

• Journal of Korean Society of Archives and Records Management
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• v.14 no.2
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• pp.83-115
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• 2014

The study aims to identify the problems of the research support service in presidential archives for users who use archives for scholarly purposes. For these purposes, the study conducted a literature survey. Moreover, this study compared and analyzed the content of presidential archives' Web sites between the U.S. and Korea. In addition, we examined the interviews via e-mail with an archivist working in the presidential archives in the U.S. and gained the materials from the presidential archives in Korea through a request of information disclosure. It was found that six improvements were considered by academic users to meet their needs. Consequently, based on the analysis, a research support services framework consisting of a service category was developed. With the proposed services, the academic utilization of presidential archives can be facilitated.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.2
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• pp.121-127
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• 2000

Kinematic GPS surveying which can obtain much 3D topographical information through short-time measurement is being utilized mainly in the short baseline less than a few kilometers. Because the decision of position for the long baseline depends on the static GPS surveying which needs long time measurement, the method for measuring the position of long baseline is needed. In this study, the accuracy of the baseline according to the baseline distance, ephemeris, and observation time by GPS surveying is analysed to confirm the application of kinematic GPS surveying for the long baseline. As the result of this, the acquisition of 3D topographical information by GPS surveying in a few minutes will be possible when PDOP is less than 4, and the fast precise ephemeris is used within 60 km. Also, the accuracy is similar to that of final precise ephemeris of IGS. If a lot of studies about the long baseline kinematic GPS surveying are processed, the acquisition of topographical information for various industry including land development will be obtained more efficiently.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1899-1907
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• 2013

This paper presents an efficient defect detection and classification system based on reference image for COF (Chip-on-Film) which encounters fatal defects after ultra fine pattern fabrication. These defects include typical ones such as open, mouse bite (near open), hard short and soft short. In order to detect these defects, conventionally it needs visual examination or electric circuits. However, these methods requires huge amount of time and money. In this paper, based on reference image, the proposed system detects fatal defect and efficiently classifies it to one of 4 types. The proposed system includes the preprocessing of the test image, the extraction of ROI, the analysis of local binary pattern and classification. Through simulations with lots of sample images, it is shown that the proposed system is very efficient in reducing huge amount of time and money for detecting the defects of ultra fine pattern COF.

• Journal of Information Technology Services
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• v.14 no.3
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• pp.99-116
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• 2015

The concept of Cloud computing has been introduced in the IT field over 10 years and industry has been expanding constantly. However, compare to the maturity of global market, Korea cloud computing industry is only in the early stage. Even the Korea has advantages in technology infrastructure; the pace of Korea cloud computing market growth is taking a serious downturn. Under these circumstances, it is needed to be discussing that strategy for expanding the cloud computing market size and for sustaining global competitiveness of local companies. Previous studies on plans for Korea cloud computing market has been conducted since 2009 and most of them are tend to examined in demand perspective. Thus, this study aims at identifying the priority of business challenges for making better performance in the market with service provider aspects. To analyze the important factors in the providing cloud computing service, ANP methodology was applied in this study. The network model including five clusters, security, stability, performance, consumer, and institution, was defined through literature review and expert survey was conducted to collect data. As a result of ANP analysis, 'Securing service reliability' was analyzed as the most important factor and followed by 'Preparing the range of legal liability', 'Preventing personal information leakage' and 'Preventing confidential information data leakage.' The priority of result indicates that service provider needs to focus on to make the secured service environment. This study has significance on analyzing the priority of business challenges in the service provider perspective. This study will provide useful guidelines to for establishing strategies in cloud computing market.

• Journal of Distribution Science
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• v.17 no.1
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• pp.89-94
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• 2019

Purpose - In recent digital information society, the most important factor of to increase the firm value of the distribution company is not the activity to increase the sales through the general advertisement of the unspecified majority by purchasing the finished product, but to grasp the needs of the consumers and to develop a new distribution platform that connects producers and consumers directly through consumer-tailored advertisements centering on e-commerce. Therefore each company in the distribution industry is spending a lot on research and development investment to innovate the distribution technology and distribution system, and the research and development investment expenditures can affect firm value. The purpose of this study is to analyze the impact of research and development investment expenditures in the distribution industry on market value of the firm. Research design, data, and methodology - As a research method, the sample firms are those which are listed on korea stock exchange market from 2011 to 2017 and the research model is Ohlson(1995) model, which is a representative valuation model using accounting information. This study analyzes the effect of distribution company's research and development investment expenditures and advertising expenditures on market value of the firm Results - The results of empirical analysis show that research and development investment expenditures for developing new distribution technology and advertising expenditures for promoting sales in the distribution company are all positively related to the market value of firm. Therefore, in describing market value of the distribution company, it is shown that the research and development investment expenditures and advertising expenditures together with the net asset and net profit are the important accounting information that explains the market value of firm. This result show that investment expenditures on research and development for the innovation of distribution technology of distribution company creates intangible intellectual assets and increases market value of the firm. Conclusions - The result of this study shows that research and development investment expenditures for the new distribution technology as well as the spending for the advertisement in the future is a very important investment expenditures that can increase the market value of the distribution company.

• Journal of The Korean Association of Information Education
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• v.23 no.5
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• pp.427-440
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• 2019

Software courses required for all students regardless of their major in many universities. SW educational effectiveness model needs to be developed to enable effective communication among students, professors, and SW educators, and to identify the responsibilities of SW educators. SW educational effectiveness model based on literature review is composed of computational thinking, SW literacy, SW awareness, and SW attitude. Computational thinking, focused on analysis and design of problem solving processes, consists of decomposition, pattern recognition, abstraction, and algorithms. SW literacy involves viewing social development based on SW beyond information literacy in the digital age. The SW awareness and attitude were organized by considering the collegiate contexts. The SW educational effectiveness model will be used as the basis for diagnosis tools as further studies.

• Journal of Korean Society of Archives and Records Management
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• v.7 no.2
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• pp.73-94
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• 2007

Archival organizations have been evolving to varying users' needs. The main functional focus of earlier archival organizations has inclined to collection and preservation of data, but their current interests expand to utilization of the data collected. Therefore, today's archival organizations endeavor to procure user-oriented archival information service. This study highlights the programs initiated in last two years by 'Service Innovation Team', a special task force of National Archives of Korea organized in 2005, and presents comparative analysis of those programs with respect to the existing archival systems of National Archives and Records Administration of USA and The National Archives in UK. Additionally, the study, while emphasizing the importance of enlarging and diversifying service programs as well as promoting public awareness over archive resources, introduces the service standards of advanced nations as benchmarks for future archival service policies of pertinent organizations.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.83-97
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• 2019

As society develops, the dissemination of microdata has increased to respond to diverse analytical needs of users. Analysis of microdata for policy making, academic purposes, etc. is highly desirable in terms of value creation. However, the provision of microdata, whose usefulness is guaranteed, has a risk of exposure of personal information. Several methods have been considered to ensure the protection of personal information while ensuring the usefulness of the data. One of these methods has been studied to generate and utilize synthetic data. This paper aims to understand the synthetic data by exploring methodologies and precautions related to synthetic data. To this end, we first explain muptiple imputation, Bayesian predictive model, and Bayesian bootstrap, which are basic foundations for synthetic data. And then, we link these concepts to the construction of fully/partially synthetic data. To understand the creation of synthetic data, we review a real longitudinal synthetic data example which is based on sequential regression multivariate imputation.