• Journal of Technology Innovation
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• v.13 no.3
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• pp.101-129
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• 2005

We decompose the patent increase over the period 1982 through 2000 using the data provided by KIPO(Korean Intellectual Property Office) and also compare our results to U.S. experiences. First, we show that the contribution of the increase in the R&D spending accounts for $71\%$ of patent increase between 1982 and 2000. Second, an overall increase in patent intensity measured by patent-R&D ratio between 1982 and 2000 is explained by $234\%$ of the changes in the patent yields in individual industries rather than by the reallocation of resources. Third, we find that there is structural change in patent intensity and patenting between 1994 and 1995. The patent yields in individual industries account for $86.4\%$ of patent increase between 1994 and 1995. Fourth, two high tech fields, electrical machinery and precision instrument, account for about $80\%$ of the patent increase.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.74-81
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• 1993

To investigate the oil degrading properties of psychrotrophic bacterium Acinetobacter calcoaceticus Al-l the effects of environmental factors on this bacterium were studied. The optimal environmental conditions for cell growth rate and oil-emulsifying activity were as follows; temperature $15^{\circ}C$, pH 7.5, salt concentration 0- 3% and crude oil concentration 0.1%. Additionally the optimal concentration of Nand P source for cell growth rate and oil-emulsifying activity were 0.76 mM and 0.057 mM as $(NH_4)HS0_4$ and $K_2HP0_4$, respectively. Analysis of remnant oil by gas chromatography showed time dependent oil degradation pattern by A. calcoaceticus during cultivation; At lOoe and $15^{circ}$e, most alkane peaks were disappeared and it showed large quantities of crude oil were degraded. But at $25^{circ}$e alkane compounds in the crude oil were partially degraded even after 120 hours incubation.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.11-15
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• 1998

Carbofuran was incubated for four weeks in five types of paddy soil samples at $25^{\circ}C$. The soil samples prepared in the study were as follows : control soil, sterilized soil, 10% cellulose added soil, 10% cellulose and 1% ferrous sulfate added soil, and 10% cellulose and 1% magnesium sulfate added soil. The degradation rate of carbofuran was significantly decreased(p<0.05) in sterilized soil.The degradation rate of carbofuran was significantly decreased by addition of cellulose(p<0.05) in femous sulfate added soil and magnesium sulfate added soil(p<0.01).

• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.161-168
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• 2016

In this study, growth enhancing effect of hatchery waste egg decomposed liquid fertilizer in pepper plant cultivation through chlorophyll fluorescence (O-J-I-P) analysis. In a whole growth period, egg decomposed fertilizer treated pepper grew well than non treated plant, though it was not statistically significantly different. Amount of chlorophyll fluorescence of non treated plant was higher thant that of fertilizer treated plant. It is determined that eventually lead to increased photosynthesis. In this study, six parameters, Fo, ABS/RC, RC/ABS, TRo/RC, DI0/RC, and DF Total ABS were the important factors represent efficiency of photochemical responses of pepper plant treated with hatchery waste egg decomposed fertilizer.

• Journal of Adhesion and Interface
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• v.4 no.1
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• pp.18-27
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• 2003

Interfacial properties and microfailure degradation mechanisms of the oxygen-plasma treated biodegradable poly(p-dioxanone) (PPDO) fiber/poly(L-lactide) (PLLA)composites were investigated for the orthopedic applications as implant materials using micromechanical technique and surface wettability measurement. PPDO fiber reinforced PLLA composite can provide good mechanical performance for long hydrolysis time. The degree of degradation for PPDO fiber and PLLA matrix was measured by thermal analysis and optical observation. IFSS and work of adhesion, $W_a$ between PPDO fiber and PLLA matrix showed the maximum at the plasma treatment time, at 60 seconds. Work of adhesion was lineally proportional to the IFSS. PPDO fiber showed ductile microfailure modes at We initial state, whereas brittle microfailure modes appeared with elapsing hydrolysis time. Interfacial properties and microfailure degradation mechanisms can be important factors to control bioabsorbable composites performance because IFSS changes with hydrolytic degradation.

• Journal of Energy Engineering
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• v.27 no.3
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• pp.10-20
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• 2018

Due to cheap electricity tariff on agricultural use, electricity consumption in agricultural sector has grown dramatically. We evaluated the negative effects of the cheap electricity tariff such as electricity over-consumption, increased dependency on electricity, decreased electricity productivity, and unequal distribution of the benefit. We also estimated the effects of agricultral output growth, structural change, and electricity intensity change on sharp electricity consumption increase in agricultural sector between 1998 and 2016 using the Log Mean Divisia Index decomposition method. The findings reinforce the necessity of raising the electricity tariff for agricultural use.

• The Korean Journal of Financial Management
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• v.19 no.2
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• pp.49-75
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• 2002

본 연구는 과거의 수익률에 근거한 투자전략인 반대투자 전략과 모멘팀 전략의 성과를 분석 하고 있다. 이러한 투자전략의 성과와 주식수익률의 시계열적 특성간의 관련성을 밝히고, 투자 성과를 기업고유 요인에 대한 주가의 과잉반응, 시장의 공통요인에 대한 주가의 반응, 그리고 개별주식의 평균수익률의 횡단면적 공분산에 기인한 부분으로 각각 분해하고 있다. 모멘팀 전략은 1주일 이상 6개월 정도의 포트폴리오 재구성 기간에 대하여 양의 성과를 보이고 있으며, 반대투자 전략은 3개월 이상 6개월의 정도의 기간에 대하여 유의적인 성과가 나타나고 있지만, 상승국면에서는 양의 성과가 나타나고 하락국면에서는 음의 성과가 나타나고 있다. 투자전략의 성과는 1주일 이내의 기간에 대해서는 수익률의 자기공분산에 의하여 주로 설명되며, 1개월에서 3개월 정도의 기간에 대해서는 교차공분산에 의하여 주로 설명되고, 6개월의 기간에 대해서는 개별주식 평균수익률의 횡단면적 분산에 의하여 주로 설명되고 있는 것으로 나타났다. 기간이 짧은 경우에는 투자성과가 주로 기업고유 요인에 대한 지연된 반응에 의하여 설명되며, 기간이 길어짐에 따라 주식수익률은 기업고유 요인에 대하여 과잉반응하는 것으로 나타나고 있다. 시장의 공통요인에 대해서 대체로 지연된 반응이 나타나며 기간이 길어짐에 따라 소규모기업의 주식은 시장의 공통정보에 대하여 과잉반응하는 것으로 나타났다.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.622-627
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• 2009

The objectives of this study were to evaluate a protease suitable for the enzymatic hydrolysis of a snow crab processing by-product (SPB) and to optimize the hydrolysis conditions using response surface methodology (RSM). The SPB was hydrolyzed at $50^{\circ}C$ and pH 7.0-7.2 to obtain various degree of hydrolysis (DH) using Flavourzyme at an enzyme/substrate (E/S) ratio of 3.0%. The reaction progress curve exhibited an initial fast reaction rate followed by a slowing of the rate. The DH was increased to 30% at 90 min with a final DH 32 to 36%. A central composite experimental design having three independent variables (reaction temperature, reaction time, and E/S ratio) with five levels was used to optimize the enzymatic hydrolysis conditions. Based on the DH data, the optimum reaction conditions for the enzymatic hydrolysis of the SPB were a temperature of $51.8^{\circ}C$, reaction time of 4 hr 45 min, and an E/S ratio of 3.8%. It was demonstrated that the enzymatic hydrolysate of SPB could be used as a flavoring agent or a source of precursors for the production of reaction flavors.

• Korean Journal of Social Welfare
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• v.64 no.2
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• pp.55-83
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• 2012

Self-employment rate is high in Korean labor market, while the income gap within self-employed is also high. Although, there are very few studies that addressed on the income inequality of self-employed. Thus, this study has measured the earnings inequality of self-employed by generalized entropy indices and decomposed inequality factor and trend. The empirical study is based on Korea Welfare Panel Study wave 1~4. The main result from this analysis is summarized in three points. Firstly, earnings inequality of self-employed is severely high and the earnings polarization within self-employed has become more serious in Korea. Secondly, this study provides the evidence that the main factor of earnings inequality of self-employed is the status of self-employment, education level, age group, workplace scale and industry. Thirdly, the contribution of relative changes in the incomes of the status of self-employment is the largest to the inequality trend. In terms of education level, age group and industry, the increase of inequality within group(pure effect) mainly attributes to the rise of earnings inequality of self-employed and the change effect of group composition contributes to deterioration of inequality.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.125-134
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• 2021

With the rapid development of the film industry, the number of films is significantly increasing and movie recommendation system can help user to predict the preferences of users based on their past behavior or feedback. This paper proposes a movie recommendation system based on the latent factor model with the adjustment of mean and bias in rating. Singular value decomposition is used to decompose the rating matrix and stochastic gradient descent is used to optimize the parameters for least-square loss function. And root mean square error is used to evaluate the performance of the proposed system. We implement the proposed system with Surprise package. The simulation results shows that root mean square error is 0.671 and the proposed system has good performance compared to other papers.