• Journal of Digital Convergence
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• v.15 no.4
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• pp.275-284
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• 2017

TACAN(TACtical Air Navigation) was created to support military aircraft's short range navigation (200~300 mile). TACAN must fulfill a condition of MIL-STD-291C, the U.S. Military Standards, which addresses the sum of 15Hz and 135Hz should be within 55%, following the factor of modulations for both to be $21{\pm}9%$ each. Within the existing TACAN antenna, modulation factor for 15Hz and 135Hz are created differently depending on its diameter, wavelength, angle of gradient, internal modulation method or using frequency code. It brings up a problem where applications needed to be stopped and repaired when modulating signal exceeds the standard of MIL-STD-291C since the existing TACAN antenna does not have coordination function. Hence, plan and produce a modulating signal generator using FPGA, and check the changes in the modulation factor for 15HZ and 135Hz, depending on the values that have been set in each criteria. Moreover, allow the modulating signal generator to be automatically adjusted based on the monitoring signal emitted by antenna, and place alarm sound just in case if it exceeds the standard.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.42-48
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• 2008

Next generation wireless communication systems require RF transceivers that enable multiband/multimode operations. Polar transmitters are known as good candidates for high data rate systems such as EDGE (Enhanced Data Rates for GSM Evolution), WCDMA (Wideband Code Division Multiple Access), and WLAN (Wireless Local Area Network) because they can obtain high efficiency by using efficient switched-mode RF power amplifiers. In this paper, we investigate the performance of a simple peak windowing scheme for the OFDM (Orthogonal frequency Division Multiplexing) polar transmitter, which requires no change of a receiver structure or no additional information transmission. The approach we employed is to apply the peak windowing scheme to the amplitude modulated signals of the polar transmitter to reduce the PAPR (Peak-to-Average Power Ratio). The BER (Bit Error Rate) and EVM (Error Vector Magnitude) performances are measured for various window types and lengths. The simulation results demonstrate that the proposed algorithm mitigates out-of-band distortion introduced by clipping along with PAPR reduction.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.145-152
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• 2009

Domestic Kori-1 MCR was partially modified in 2007 and will be renovated entirely in 2013. Digital devices partially replacing original analog devices have been introduced and standard alone computer systems such as SPDS have been integrated into the plant computer. Upgrading KSNP's MCR based on the ditalization is planned for 2015. However, the site engineers and operators are reluctant to the advanced systems. Therefore, a prototype for the KSNP's advanced MCR has been developed to increase the acceptance level of the operators and field engineers and also, to evaluate user interfaces and I&C architecture. For enhancing support of the operators' work, a P&ID based display system composed of multi-layers, which are linked through a context sensitive menu each other, has been adopted. The $1^{st}$ layer displays a simplified P&ID, the $2^{nd}$ layer control related diagrams such as controllers and logic diagrams, the $3^{rd}$ layer trends, etc. The end point view of MCR for KSNP is also suggested considering reliability and operability of the digital systems. Additionally, modernization strategies over the overhaul periods, that do not have much impact on operation and configuration efforts are suggested.

• Journal of the Korean Chemical Society
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• v.57 no.1
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• pp.138-146
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• 2013

This study examined the characteristics of the National Assessment of Educational Achievement (NAEA) in Science according to gender. It investigated gender achievement differences in the science section of the 2010 NAEA, the ratio of gender difference in achievement, the ratio of correct answers within each content domain and behavioral domain, and the items which showed high differences between males and females. The results indicate first, that, for 9th graders, females outperformed males in academic achievement in science. Second, with respect to the ratio of correct answers, males outperformed females in the advanced and below basic level groups, but females outperformed males in intermediate level groups. Third, females outperformed males in knowledge and inquiry in the behavior domains, and in chemistry and biology in the content domains. Fourth, an analysis of the items showing the largest gender gap indicated that males outperformed females in interpreting data, while females outperformed males in the items concerned with daily life and items related to the memorization of rules. This research on gender differences in science will allow teachers to complement the weaknesses of students when they study science, and support improved instructional methods in science.

• Management & Information Systems Review
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• v.35 no.4
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• pp.141-153
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• 2016

This study estimates the productivity change of pharmaceutical industry and decompose the change into technical efficiency change and technological change to explore ways to improve the productive efficiency. Unlike most previous studies, this study employs the non-radial and non-oriented slacks-based Malmquist productivity index which can deals directly with the input excesses and output shortfalls. In addition a smoothed bootstrap method is applied to estimate statistical confidence intervals for the Malmquist Index and its components. For the empirical analysis a balanced panel data set is constructed covering ten years over the period from 2005 to 2014. The input variables used in this study are number of workers, tangible assets and major production cost. The gross production is selected as a main output variable. The empirical results suggest that the productivity of pharmaceutical industry has decreased due mainly to decline in the technological progress rather than improvements in technical efficiency. An analysis result shows that the scale efficiency outweighs the pure efficiency in determining the technical efficiency of pharmaceutical industry. Therefore, in order to enhance the competitiveness of domestic pharmaceutical industry, it is important to continue supporting policies to promote the technology innovation capability through efficient R&D investment and industry reform strategy.

• Korean Journal of Social Welfare
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• v.53
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• pp.75-104
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• 2003

This study was performed to analyze the process and develop the pattern of school dropout in the context of the Korean educational systems. Participants were 30 adolescents experiencing dropout one more times and their age ranged from 16 to 23. A major category derived and analysed from a grounded theory method of Strauss and Corbin(1990). The qualitative analysis indicated that dropout is contradictory experiences in Korea. Because it is emancipation from various distress of school systems as well as loss of various benefit as students, Main causes of dropout were identity problems, school frustrations(failure in school achievements), environmental disadvantaged and delinquencies. Sometimes these various causes are emerged at the same time. Most important condition of context which was decided was whether dropout was voluntary and considered. After dropout from school, it was important if there were resources such as emotional and informative supports. Especially informative support was critical to adjust after dropout. Dropout experience was divided largely into 4 patterns such as type of 'searching the identity', 'being disorganized', 'escaping' and 'frustration'. In chronological analysis resulted in 4 stages including 'stage I. loss of motivation', 'stage II. escaping from school', 'stage III. trial and error', 'stage IV changing the meaning of dropout in the life.

• Korean Journal of Social Welfare
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• v.53
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• pp.179-207
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• 2003

The purpose of this study is to find out the structural characteristics of interorganizational networks for women, and to identify the magnitude of efficient structure for network using 30 organizations for women in Buchon. This study attempted to examine the characteristic of interorganizational networks through searching out the central organization and block modeling. The research sample was 30 organizations, and the data analyzed by UCINET V and KP(Krack Plot) 3.1. The results show that public agencies are central organizations of all dimensions(information exchange, client referral, cooperation, resource exchange) and they also play an important part as intermediary of interorganizational network. A prominent characteristics of network is "ggiri-network" that means network between similar agencies. This finding provides important strategy to build and expand the network. Also this finding can be direction of network structure to meet women's needs and empower women.

• Journal of Korea Port Economic Association
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• v.30 no.4
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• pp.131-149
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• 2014

The objective of this study is to describe and determine how and to what extent size of firm, operating vessels and interest cost, leverage, debit maturity, growth opportunity and cash flow affect the cash holdings of Korean shipping companies. A sample of 38 Korean shipping firms for a period of 9 years(from 2005 to 2013) was selected. In panel data regression, this study finds that cash holdings are negatively affected by firm size, operating vessel size and debit maturity, and positively affected by volume of interest costs. In firm's group of relatively large volume of operating vessel, it's cash holdings are affected by debit maturity, cash flows and growth opportunity but in firm's group of small volume of it, interest cost, debit maturity and operating vessel's size are related with cash holdings. It proved that determinants of cash holdings in a high interest costing group are size of operating vessel, interest cost and debt maturity. On the other hand, debit maturity, growth opportunity, firm size and extent volume of vessels are associated with cash holdings in relatively row interest costing group.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.1
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• pp.11-20
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• 2010

Oyster production is playing an important role in domestic aquaculture, but facing some problems such as exports decrease, a slowdown in domestic demand and marine environmental deterioration. In order to obtain the suitable and sustainable oyster production, suitable sites selection is an important step in oyster aquaculture. This study was conducted to identify the suitable sites for lunging culture of oyster using Geographic Information System(GIS)-based multi-criteria evaluation methods. Most of the parameters were extracted by Inverse Distance Weighted(IDW) methods in GIS and eight parameters were grouped into two basic sub-models for oyster aquaculture, namely oyster growth sub-model(Sea Temperature, Salinity, Hydrodynamics, Chlorophyll-a) and environment sub-model(Bottom DO, TOC, Sediment AVS, Benthic Diversity). Suitability scores were ranked on a scale from 1(leased suitable) and 8(most suitable), and about 80.1% of the total potential area had the highest scores 5 and 6. These areas were shown to have the optimum condition for oyster culture in GeojeHansan Bay. This method to identify suitable sites for oyster culture may be used to develop bivalve culture management system for supporting a decision making.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.193-199
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• 2017

The research is aimed at finding out the relationship between vocational stress and willingness to engage in vocational stress, which measures vocational stress and the ability to cope with the job, and how the job stress relates to job mobility. First of all, the job stress and willingness to transfer jobs related to sexual harassment related agencies have a positive correlation, while self-exploitation, job stress, and willingness to move jobs have shown negative correlation. Second, the self-assessment of self-assessment of ego resilience has served as a complete parameter in relation to the relationship between employee motivation and willingness to leave the job, which is the job of occupational duties. Based on this study, it is important to note that self-reference is an important factor in determining the role of job stress in the workforce because of its self-reference of job stress and motivation in relation to job stress.