• Journal of information and communication convergence engineering
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• v.8 no.6
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• pp.655-659
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• 2010

In the conventional PNC scheme, the relay node requires simultaneous transmission of two source nodes with strict power control and carrier-phase matching between two received symbols. However, this pre-equalization process at source nodes is not practical in fading channels. In this letter, we propose a novel physical-layer network coding (PNC) scheme with log-likelihood ratio (LLR) conversion for fading channels, which utilizes not pre-equalizer at transmitters (source nodes) but joint detector at receiver (relay node). The proposed PNC requires only channel side information at the receiver (CSIR), which is far more practical assumption in fading channels. In addition, the proposed PNC scheme can use the conventional modulation scheme like M-QAM regardless of modulation order, while the conventional PNC scheme requires reconfiguration of modulation scheme at the source nodes for detection of the received signal at relay node. We consider the combination of the proposed PNC and channel coding, and find that the proposed PNC scheme is easily combined the linear channel codes such as turbo codes, LDPC, and convolutional codes.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.982-987
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• 2004

Most design practices have not taken advantage of the advanced theories in the modern fracture mechanics and finite element analysis due to complexity of analysis as well as the large quantity of vaguely defined parameters in actual designs. This paper considers fatigue problems in bridge structures using effective analytical and design tools from the field of qualitative constraint reasoning. A set of software modules was developed for fatigue analysis ,and evaluation, which is easily applicable in engineering practices of bridge designers. The software modules integrate techniques in the field of knowledge representation and qualitative reasoning, into the conventional fatigue analysis. The techniques enable the use complex analysis formulations to tackle practical problems with uncertainties, and present the design outcome in two-dimensional design space. Appropriate engineering assumptions and judgments in carrying out these procedures, often the most difficult part for practicing engineers, can be partially produced by using qualitative reasoning to define the trends and ranges, interval constraint analysis to derive the controlling parameters, as well as design space to account for practical experience. This paper depicts a way of complex analysis to practical engineering designs with qualitative reasoning.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.455-460
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• 2005

Preventive diagnostic system for power transformer prevents the sudden power failure through monitoring of abnormal symptoms. KEPCO has adopted the preventive diagnostic system at nine 345kV substations since 1997. Application techniques of the diagnostic sensors were settled, but diagnostic algorithm and practical use of accumulated data are not yet established. To build up the diagnostic algorithm and effective use of the preventive diagnostic system, the reliability of the data accumulated in a server computer is very important. Therefore, this paper describes problem when apply system to substation and solution way to improve reliability of the system

• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.375-384
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• 2007

As teachings that use the ICT are more popular, many studies on the dynamic geometry environment(DGE) are under way. An important factor emphasized in the studies is to practical use learning activities of learners. In this study, we first define the learning history data in DGE. Second we develop a prototype of the DGE that is able to collect and analyze the learning history data automatically. The environment enables not only to grasp leaning history but also to create and manage new learning objects.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.1
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• pp.71-76
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• 2010

There are two ways of wireless network practice. One of the ways is to use wireless network equipments directly. And the other way is to use wireless network simulators. But they have some problems such that space limitation, required equipments and setting up the simulators for each wireless network practices. So, in this paper, we showed the model of application for students and professor is modeled from real practice environment. We also suggested algorithms for implementation of an application about wireless network practice based on web.

• Journal of Family Resource Management and Policy Review
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• v.5 no.2
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• pp.45-57
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• 2001

The object of this study is to understand the determinants of housewives’internet usage, examining empirically their internet usage motivation and activity, and to find the way to promote housewives’internet usage. The major findings of this study can be summarized as follows; 1) the housewives’internet usage motivation was composed of the motivation to make a good use of leisure by internet, self-developmental, practical, and children educational motivations. The mean score of self-developmental motivation was the highest in the internet users and that of child educational motivation was the highest in the non-internet users. 2) the significant variables which affected on the internee usage of housewives were age, internet related housing environment the perception of internet usefulness, internet usage of husband, the motivation to make a good use of leisure by internet, and children educational motivation.

• Education of Primary School Mathematics
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• v.6 no.1
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• pp.29-40
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• 2002

Fairy-tales give students opportunities to build connections between a problem-solving situation and mathematics as well as to communicate solutions through writing, symbols, and diagrams. Therefore, the purpose of this paper is to introduce how to use fairy-tales in elementary mathematics classroom in order to develope student's mathematical concepts and process in terms of the following areas: ⑴ reconstructing literature ⑵ understanding concepts ⑶ problem posing activity. To be useful, mathematics should be taught in contexts that are meaningful and relevant to learners. Therefore using fairy-tales as a vehicle to teach mathematics gives students a chance to develope mathematics understanding in a natural, meaningful way, and to enhance problem posing and problem solving ability. Further, future study will continue to foster how fairy-tales literatures will enhance children's mathematics knowledge and influence on their mathematics performance.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.147-158
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• 2017

Internet is changing the way consumers shop and buy goods and services, and has rapidly evolved into a global phenomenon. The primary purpose of this study is to investigate the influence of consumer's on-line shopping values on satisfaction and intention to re-use. Economic value, emotional value, convenience value, social value, product variety were identified as affecting factors of satisfaction and intention to re-use of on-line shopping purchasing based on prior studies of on-line shopping behavior. This study tested the hypothesized model using the data from 132 consumers who have purchased products in on-line shopping mall. According to the result, economic value, emotional value, product variety are significantly related to the consumer satisfaction but convenience value, social value are not. Consumer satisfaction of online purchasing was also shown to be related to the intention to re-use. It can provide practical guidelines on effective operation strategies for consumer loyalty.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.1
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• pp.197-207
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• 2015

A new communication revolution such as social networking service (SNS) has been transforming the way of interaction between people in both of individual level and organizational level. Recently many people have switched to closed type SNS such as Naver Band and Kakao group due to the several reasons. The purpose of this study is to investigate the usage motivation and satisfaction of closed type SNS based on use and gratifications perspectives. Based on prior studies on use and gratifications of Internet-related media and SNS, information motivation, relationship motivation, pleasure/entertainment motivation, self-expression motivation, work motivation were identified as usage motivation of closed type SNS. According to the results, relationship motivation and work motivation were found to be significantly related to the satisfaction. But other motivation factors(information motivation, pleasure/entertainment motivation, self-expression motivation) are not significantly related to the satisfaction. Then satisfaction was found to be significantly related to the intention to use. This study contributes to give companies providing closed type SNS and using it as a marketing tool with the base of activation strategies and practical implications.

• International Commerce and Information Review
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• v.16 no.5
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• pp.249-273
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• 2014

This study aims to find implications of Korean FTAs and to suggest policy recommendations to facilitate the utilization of FTAs based on the field survey of more than 1,000 trading firms According to the survey, most of the trading firms have utilized FTAs more than once and had agreed that the FTAs have contributed to expansion of their business and trade with partners. However, still a number of firms responded that they have never used FTAs. Even those who are utilizing FTAs expressed difficulties in conforming to the complex rules of origin verification processes and lack of practical information on how to use FTAs. Therefore, government policies need to be more focused on elevating FTA utilization rate and meeting the practical use of FTAs by trading firms. In addition, trading firms were found to express preference to potential FTA partners with large economies in the East Asia and were in the opinion that future FTA agreements should be approached in a way that can reflect the practical interest of the firms.