• Journal of Welding and Joining
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• v.31 no.3
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• pp.39-43
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• 2013

It is difficult to feed welding wire stably, when the distance between welding wire feeder and welding torch is far enough. In order to solve this problem, arranging a extension wire feeder between them could be one of useful methods. However, the welding wire could be twisted up in the extension cable between extension and terminal wire feeders in the case that RPM of extension wire feeding motor is higher than that of terminal motor. In this study, feeding problem of normal push-pull wire feeding system occurred at low welding current range less than 250A. In order to solve the problem, two new wire feeding systems of push-pull type were introduced. Welding wire feeding tests were preformed in the range of 150A to 400A with the developed push-pull feeding system. In addition, weldability test was performed at the welding current of 200A, 300A, and 400A. The welding wire twisting problem that was observed in the normal feeding system did not occur in the new push-pull wire feeding system.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.801-803
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• 2004

The current drive in an MOSFET is limited by the intrinsic channel resistance. All the other parasitic elements in a device structure playa significant role and degrade the device performance. These other resistances need to be less than $10{\%}-20{\%}$ of the channel resistance. To achieve the requirements, we should investigate the methodology of separation and quantification of those resistances. In this paper, we developed the extraction method of resistances using calibrated TCAD simulation. The resistance of the extension region is also partially determined by the formation of a surface accumulation region that forms under the gate in the tail region of the extension profile. This resistance is strongly affected by the abruptness of the extension profile because the steeper the profile is, the shorter this accumulation region will be.

• Journal of Agricultural Extension & Community Development
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• v.16 no.1
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• pp.51-67
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• 2009

This study was carried out to investigate the major factors of the successful development of Doi Chaang Coffee Complex, Chiang Rai of Thailand. Data were gathered through field survey, library research and internet so on. Interviews were conducted with specialist, community leaders, board member of Doi Chaang Coffee Company from 14 to 19, January 2007. The major factors for the successful development observed were as follows: 1) Successful selection of crops and farming system(SALT) with regards of slopes and meteorological condition; 2) Leadership of the King of Thailand and the chief of Akha in terms of attitudinal change of hill-tribes in agriculture extension; 3) supporting by Royal Project Foundation; 4) Quality control through post harvest management by cooperative system; 5) Cooperation between the Coffee Producers' Cooperatives of Thailand and for the international Doi Chaang Coffee Corporation of Canada in terms of fair trade and so on.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.431-433
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• 2018

This paper proposes the system that offer super-wideband speech which is made by artificial bandwidth extension technique using wideband speech signal in time-domain. wideband excitation signal and line spectrum pair(LSP) are extracted based on source-filter model in time-domain. Two parameters are extended by each bandwidth extension algorithms, and then, super-wideband speech parameters are estimated. and synthesized. Subjective test shows super-wideband speech is better speech quality than wideband speech signal.

• Journal of Agricultural Extension & Community Development
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• v.8 no.1
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• pp.15-23
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• 2001

As Internet and World Wide Web become more popular in our society, the interests in effective application to the field of rural development and agricultural extension service are increasing. The potential in Web-based agricultural extension service is expressed in many areas, such as agriculture information, Web-based training and education, and virtual rural community for rural development and agricultural extension service. The research on the Web and its related issues has been conducted in many ways, but the interests in the competencies and skills of staff who are in charge of Web developing and managing have not been exposed yet. The purpose of this study was to investigate the important competencies and skills for Web developing and managing for enhancing the effectiveness of rural development and agricultural extension service. Twelve extension service staff and on staff in the extension service support center were interviewed. The results of study showed that there were eight essential competencies; competencies to understand rural community and agricultural extension service, to understand the farmers as Web users, to design and develop effective Web sites, to understand the nature of hypertext, to utilize instruction theories, to absorb new technology, to manage projects, and to utilize external sources. The results of study also showed that there was lack of support systems for Web development and information. Overall, the findings of this study suggest that establishing long-term education and training system for technology, electronic performance support systems, and cooperation with universities and colleges for technology are of particular importance for promoting Web-based extension services.

• Journal of Agricultural Extension & Community Development
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• v.20 no.4
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• pp.1045-1078
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• 2013

The purpose of the present study is to improve the effectiveness of Korea's ODA projects on agricultural technology transfer to Africa. This study investigates agricultural extension system of African countries and provides a direction of the systematic strategies of the Korean ODAs on agricultural technology. This study pays particular attention on Africanization of agricultural technology transfer of the Korean ODA strategies. Unlike the previous studies focusing mainly on micro level investigation on the ODA strategy development, the present study incorporates the agricultural technology dissemination system of Ethiopia and Uganda in a macro perspective to develop a desirable form of the ODA strategy. The findings illustrate that the technology dissemination systems of the case countries have different characteristics depending on the function and organization of extension agency. And their functional capability and role segmentation by the extension agency are differently configured, too. In case of Ethiopia, top-down structure for the agricultural extension system has been built. Farmers' group and field agent of the information delivery system has expanded their participation into the system. However, we also find that the system of Ethiopia still lacks effective use of its existing technology, since it puts more emphasis on management aspects than improvement of agricultural productivity for farmers. On the other hand, even though Uganda has established participatory extension system that encompasses the entire agencies of the extension system, government efforts to enhance the extension system are still concentrated on expanding research functions rather than technical dissemination. The results imply that promoting and strengthening localization of the ODA strategy has to be developed to make localization policy of the Korean ODA. The present study concludes with some specific policy implications for necessary conditions of the agricultural development in African countries.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.6 s.97
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• pp.586-593
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• 2005

It is very important to reduce the PAPR(Peak to Average Power Ratio) in the OFDM(Orthogonal Frequency Division Multiplexing) communication system. We propose an ACE(Active Constellation Extension) method that does not require the side information unlike the conventional PTS and SLM method. This ACE method is to clip the OFDM signal for the PAPR reduction. Then, the basic constellation actively moves into the higher level of M-QAM for the constellation extension due to the clipping. The already existing M-QAM system can be available so that it can be easily realized. So, we can get the target PAPR by the extension of the constellation level. In this paper, we can find the PAPR reduction of 4 dB by the 16-QAM extension, and can achieve the target PAPR by the 64-QAM ACE(Active Constellation Extension).

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.819-823
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• 2011

The present study evaluated the seasonal changes of the soil microbial population by selected media in an organic farming system (OFS) with rye rotation cropping management compared to those in a conventional farming system (CFS) with chemical fertilizers, pesticide and herbicide from May 2009 to October 2010 in an upland field. With the exception of fungi, populations of aerobic bacteria, Gram-negative bacteria, and Bacillus spp. were higher in the OFS soil during soybean-growing stages. In addition, populations of aerobic bacteria, Gram-negative bacteria, and Bacillus spp. in the OFS soil were nearly two times more than those in the CFS soil on reproductive growth stages. Our findings suggested that Bacillus spp. should be considered as responsible factor for microbial population differentiation observed between the OFS and the CFS in upland fields.

• Korean Journal of Social Welfare
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• v.61 no.3
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• pp.155-177
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• 2009

This is a study to review provision and production system of social services in European welfare states and find out implications to Korea. Firstly, trends of social service extension and reorganization in welfare state restructuring process, and approaches in interventions to social service system are theoretically discussed. In this discussion, we focus on the discussion of Jessop's workfare in social service extension and reorganization and the concept of innovation in intervention to social service system by state. Then, In order to look at details of reorganization of social service system through restructuring of European welfare states, German case is reviewed. In this review, the reorganization of social service provision and production system in Germany is analyzed through the comparison with the pre-existing system in terms of relationships with public sector as well as between public and private sector respectively. Finally, implications of the European and German experiences to Korea are explored. In order to do so, the state of social services in Korea is examined whilst comparing to the European development process of social services. Also, pros and cons of the electronic voucher scheme, which transforming the social service provision system in Korea, are discussed then challenges in Korean social service delivery system are discussed.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3221-3223
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• 2007

Recently, nuclear power plant companies have been extending the turbine valve test interval to reduce the potential of the reactor trip accompanied with a turbine valve test and to improve the NPP's economy through the reduction of unexpected plant trip or decreased operation. In these regards, the extension of the test interval for turbine valves was reviewed in detail. The effect on the destructive overspeed probability due to the test interval change of turbine valves is evaluated by Fault Tree Analysis(FTA) method. Even though the test interval of turbine valves is changed from 1 month to 3 months, the analysis result shows that the reliability of turbine over speed protection system meets acceptance criteria of 1.0E-4/yr. This result will be used as the technical basis on the extension of the test interval for turbine valves. In this paper, the propriety of the turbine valve test interval extension is explained through the review on the turbine valve test interval status of turbine overspeed protection system, the analysis on the annual turbine missile frequency and the probability evaluation of the destructive overspeed due to the test interval extension.