• Journal of Satellite, Information and Communications
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• v.8 no.3
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• pp.1-5
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• 2013

In this paper, we present a conversion algorithm of the oblique ionogram obtained from Jeju and Icheon to the equivalent vertical ionogram of the path mid-point, based on some equivalence theorems between the vertical sounding and the oblique sounding for the ionosphere. And in order to verify the conversion algorithm under the condition of no vertical ionosonde at the mid-point on the test path, the equivalent vertical ionograms are compared to the real vertical ionograms measured adjacently in space-time. The comparison results show that the conversion algorithm performs well for the short-path oblique ionogram and the equivalent vertical ionograms could be applied to get the electron density profiles at the mid-point.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.2
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• pp.176-184
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• 1993

The glasses, which the $\beta$-spodumene as the principal crystalline phase could be precipitated, were melted by adding >, $P_2O_5, TiO_2, ZrO_2 in the Li_2O-Al_2O_3-SiO_2$ system. In order to achieve the glass-ceramic body of near-theoritical density by sintering method, the optimum condition of heat treatment, the effect of glass powder size and the properties were investigated by DTA, XRD, bulk density, thermal expansion and SEM. Addition of $P_20_5$ imProved the tendency of sintering and the sample with 9wt% $P_20_5$ content was the most dense OOdy by sintering method. The optimum condition of heat treatmemt was sintered for densitification at $740^{\circ}C$ and crystallized at $950^{\circ}C$. In the optimum condition, the relative density was above 90% and the thermal expansion was negative about $-1{\times}10^{-7}/^{\circ}C$.

• International Area Studies Review
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• v.22 no.1
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• pp.41-60
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• 2018

It is widely known that the increased productivity lead to a decrease in energy consumption. The policy for reducing energy consumption is also focusing on the improvement of firm's productivity. However, the issue of productivity dilemma phenomenon is recently raised in various fields. It is phenomenon that the increased productivity rather lead to a increased in energy consumption through a rise in output. This paper analyzed the presence of productivity dilemma in korean firm using Tang et al(2015)'s theoretical model. To closely analyze, I performed the analysis using 715 firms during 2011-2015 and estimated the model using system GMM to minimize the endogeneity. The results show that total effect of productivity had a significantly negative coefficient. It is implies that the increased productivity doesn't increase energy consumption. In other word, this paper could not identified productivity dilemma and so did in overseas investment firm and national firm cases.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.79-92
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• 2019

Titanium hydride potassium perchlorate (THPP) is one of the commonly utilized pyrotechnic materials in aerospace industries. The current study elucidates the effects of hygrothermal aging on the combustion of THPP experimentally. First, applying the Differential Scanning Calorimetry (DSC) and isocoversional method, both the delay of reaction start and decrease in maximum reaction rate were observed. The kinetics parameters tended to fluctuate depending the thermal reaction or intermediate product formation of THPP. Also, the oxidants decomposition and fuel oxidation phenomenon were discovered by X-ray photoelectron spectroscopy (XPS). The experimental heat from DSC data were verified as reasonable by comparing with the theoretical heat obtained utilizing both THPP formulation from XPS and NASA Chemical Equilibrium with Applications (CEA). Both data had identical variation trend, which expecially had the highest heat value at 10 weeks aged sample.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.35-45
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• 2011

The Salsa20/12 stream cipher selected for the final eSTREAM portfolio has a better performance than software implementation of AES using an 8-bit microprocessor with restricted memory space, In the theoretical approach, the evaluation of exploitable timing vulnerability was 'none' and the complexity of side-channel analysis was 'low', but there is no literature of the practical result of power analysis attack. Thus we propose the correlation power analysis attack method and prove the feasibility of our proposed method by practical experiments, We used an 8-bit RISC AVR microprocessor (ATmegal128L chip) to implement Salsa20/12 stream cipher without any countermeasures, and performed the experiments of power analysis based on Hamming weight model.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.3
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• pp.366-380
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• 2015

Park Geun-hye Administration has been leading HOPE Area(Living Happiness Sphere) policy as a part of strategy for the regional development. Recent study on HOPE Area policy mainly focuses on how to enhance cooperation among local governments or how to activate the HOPE area. However, as far as I found, the research on how HOPE area guideline as an institution is made and how HOPE area, the effect of the institution, is demarcated has not well been conducted. With based on these issues, this article aims to identify and examine the process of the HOPE area guideline-making and the designation of the HOPE area. For this purpose, new institutionalism is utilized for the analysis. The guideline was made through competition and compromise among a few parties concerned rather than a decision by unitary elite group, and the final outcome of the process reflected the balanced development strategy more than the growth pole development strategy. There was a tendency that the local governments try to make many HOPE areas by overlapping the HOPE areas, which are the outcomes of the bottom-up approach. In Seoul metropolitan area, a new type of HOPE area was introduced one year later than the other local regions.

• Journal of Korea Technology Innovation Society
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• v.19 no.3
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• pp.658-685
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• 2016

In technology economic theory, technology innovation through R&D is regarded as a core element of economic growth. This research analyzes how R&D input factor (R&D as a percentage of GDP, total number of researchers, the proportion of science and engineering degree) affects GDP, economic outcome variable, through mediating variable (S&T papers, patent registration). The most effective variable among R&D activity variables is following order: the number of S&T papers (0.967), the total number of researchers (0.373), the proportion of R&D expenditure (0.191), the number of patent registration (0.049), the proportion of science and engineering degree (0.007). It is that the proportion R&D expenditure and the total number of researchers shows greater indirect impact through S&T papers and patent than the direct impact on GDP. This implies the importance of high-quality human resources training and the necessity of maintaining the scale of R&D fund or the importance on GDP. Moreover, S&T papers turns out to have the greatest effect on GDP and implies new outcome and value by sharing and expanding new knowledge and technology created by R&D

• Composites Research
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• v.31 no.1
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• pp.30-36
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• 2018

The curing behavior of glass fiber reinforced epoxy prepregs based on Bisphenol-A (BPA) was studied by differential scanning calorimetry (DSC). The total heat of reaction(${\Delta}H_{total}=280.3J/g$) was determined based on the results of the dynamic heating scanning experiments. Isothermal experiments were carried out at $110{\sim}130^{\circ}C$, and it was observed that the maximum conversion and the maximum reaction rate were increased as temperature increased. Also Kamal equation was applied to analyze autocatalytic reaction of epoxy prepregs. The higher temperatures, the greater reaction rate constants ($k_1$, $k_2$). Theoretical values were calculated by these reaction rate constants and compared with experimental values. And it was confirmed that they were in reasonable agreement. At the beginning of the reaction, the experimental data and theoretical prediction were shown the same tendency, but at the end of reaction, the experimental data were smaller than theoretical predicted values due to reaction rates controlled by diffusion.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.3
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• pp.157-165
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• 2006

The change of external/internal factors of the cell rquires specific biological functions to maintain life. Such functions encourage particular genes to jnteract/regulate each other in multiple ways. Accordingly, we applied a linear decomposition model IFSA, which derives hidden variables, called the 'expression mode' that corresponds to the functions. To interpret gene interaction/regulation, we used a cross-correlation method given an expression mode. Linear decomposition models such as principal component analysis (PCA) and independent component analysis (ICA) were shown to be useful in analyzing high dimensional DNA microarray data, compared to clustering methods. These methods assume that gene expression is controlled by a linear combination of uncorrelated/indepdendent latent variables. However these methods have some difficulty in grouping similar patterns which are slightly time-delayed or asymmetric since only exactly matched Patterns are considered. In order to overcome this, we employ the (IFSA) method of [1] to locate phase- and shut-invariant features. Membership scoring functions play an important role to classify genes since linear decomposition models basically aim at data reduction not but at grouping data. We address a new function essential to the IFSA method. In this paper we stress that IFSA is useful in grouping functionally-related genes in the presence of time-shift and expression phase variance. Ultimately, we propose a new approach to investigate the multiple interaction information of genes.

• Korean journal of communication and information
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• v.43
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• pp.173-208
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• 2008

This study analyses the business performance according to the business diversification of Korean mass media enterprises from year 2003 to 2006. The conclusions drawn which could be divided into five main parts are the followings: First, newspaper companies pursue unrelated diversification in various industrial areas, in order to gain maximum profit while broadcasting companies exert themselves to provide better service by diversifying the major contents. Second, overall the interviewed companies display a constant decline in profit gained from their major business area thus establishing strategies to broaden their focus on diversification of any sort. Third, the researcher completed group analysis in regard of diversification measure resulting in division of three groups. The group which had the most immense diversification range gained the highest ROE, the lowest ROE volatility, and lesser probability of risk taking. The analysis adresses the companies broadening their business areas by researching and focusing on diversification are relatively stable in terms of the profit they gain. Fourth, the middle level group in terms of sales scale, debts, enterprise history, major share rate and high ROE group carry out diversification progressively. The sales scale affects positively to diversification, while the major share rate affects negatively to diversification. Fifth, in accordance to the research, diversification overall contributes to obtainance of successful outcome. Since there was not an immense amount of studies to be referred in the media area, the researcher interviewed and did panel discussion with numerous strategists and managers who are in charge of diversification of media companies. However, collection of only 4 years of data limits the research to be considered to be a generalized study, and does not reflect time gap between business diversification and business performance. Development is required in future studies to be established regarding the media companies' specificity different to other industries, classified the media companies into media types, and consider the time gap in the diversification activities and business performance.