• Journal of Plant Biotechnology
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• v.48 no.4
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• pp.278-288
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• 2021

The development of bioenergy through biomass has gained importance due to the increasing rates of fossil fuel depletion. Biomass is important to increase the productivity of bioethanol, and production of biomass with high biomass productivity, low lignin content, and high cellulose content is also important in this regard. Inorganic salts are important in the cultivation of biomass crops for the production of biomass with desirable characteristics. In this study, the roles of various inorganic salts in biomass and bioethanol production were investigated using an in vitro tobacco culture system. The inorganic salts evaluated in this study showed dramatic effects on tobacco plant growth. For example, H₂PO₄ substantially improved plant growth and the root/shoot (R/S) ratio. The chemical compositions of tobacco plants grown in media after removal of various inorganic salts also showed significant differences; for example, lignin content was high after Mg²⁺ removal treatment and low after K⁺ treatment and H₂PO₄ removal treatment. On the other hand, NO₃^- and H₂PO₄ treatments yielded the highest cellulose content, while enzymatic hydrolysis yielded the highest glucose concentration ratio 24 h after NH₄⁺ removal treatment. The ethanol productivity after H₂PO₄ removal treatment was 3.95% (w/v) 24 h after fermentation and 3.75% (w/v) after 36 h. These results can be used as the basis for producing high-quality biomass for future bioethanol production.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.713-721
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• 2023

Soil acidification challenges global food security by adversely influences soil fertility and agricultural productivity. Carbonized agricultural residues present a sustainable and ecofriendly way to recycle agricultural waste and mitigate soil acidification. We evaluated the effects of organic amendments on lettuce growth and soil chemical properties in two soils with different pH levels. Carbonized rice husk was produced at 600℃ for 30 min and rice husk was treated at 1% (w·w^-1). Carbonized rice husk increased soil pH, electrical conductivity, total carbon content, and nitrogen content compared with untreated and rice husk treatments. Furthermore, this study found that lettuce growth positively correlated with soil pH, with increasing soil pH up to pH 6.34 resulting in improved lettuce growth parameters. Statistical correlation analysis also supported the relationship between soil pH and lettuce growth parameters. The study findings showed that the use of carbonized rice husk increased the constituent elements of lettuce, such as carbon, nitrogen, and phosphate content. The potassium content of lettuce followed a similar trend; however, was higher in acidic soil than that in non-acidic soil. Therefore, improving the pH of acidic soil is essential to enhance agricultural productivity. It is considered advantageous to use agricultural residues following pyrolysis to improve soil pH and agricultural productivity.

• KDI Journal of Economic Policy
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• v.25 no.2
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• pp.3-53
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• 2003

Using the plant level panel data on Korean manufacturing during 1990-98 period, this study tries to assess the role of entry and exit in enhancing aggregate productivity, both qualitatively and quantitatively. Main findings of this study are summarized as follows. First, plant entry and exit rates in Korean manufacturing seem quite high: they are higher than in the U.S. or several developing countries for which comparable studies exist. Second, in line with existing studies on other countries, plant turnovers reflect underlying productivity differential in Korean manufacturing, with the "shadow of death" effect as well as selection and learning effects all present. Third, plant entry and exit account for as much as 45 and 65 percent in manufacturing productivity growth during cyclical upturn and downturn, respectively. The findings of this study show that the entry and exit of plants has been an important source of productivity growth in Korean manufacturing. Plant birth and death are mainly a process of resource reallocation from plants with relatively low and declining productivity to a group of heterogeneous plants, some of which have the potential to become highly efficient in future. The most obvious lesson from this study is that it is important to establish policy or institutional environment where efficient businesses can succeed and inefficient businesses fail.

• Journal of Korea Port Economic Association
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• v.28 no.2
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• pp.155-177
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• 2012

This paper aims at measuring the changes of Malmquist productivity and technical efficiency of Korean shipbuilding Industry and examinig their determinants utilizing the panel analysis. The increase of the technological progress was greater than technical efficiency, resulting in the increase of the total factor productivity for the period of 2004-2010. This study also employs the panel technique to analyse the effects of Employee, Dock, and Length on the changes of Malmquist productivity and technical efficiency. The dependent variables are obtained from three combinations, which are (Employee, Dock, and CGT), (Employee, Length, and CGT), and (Dock, and Length, and CGT). The empirical results show that all of the explanatory variables have a positive effect on the change of Malmquist productivity and technical efficiency.

• Journal of Korea Port Economic Association
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• v.35 no.1
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• pp.57-76
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• 2019

This study deals with the determinants of employment productivity of transportation labor, who are the main agents of the transportation industry that has made significant contributions to our country's industrial development. The study selected the determinants of employment productivity using the Korea Labor and Income Panel Study data, and analyzed the effects of various factors using panel logistic regression, panel OLS model, and panel robust regression. The results were as follows. First, a more positive effect was shown when employees held a regular job, had a "high level of education", "joining the labor union" and "experiencing vocational training". Second, in the case of job security, having a "high level of education" and "joining the labor union" showed a more positive effect; further, job security was higher for employees who worked in a "big company" or were "married". Third, in the case of higher income productivity, higher values of "age", "academic ability" and "company size" had a more positive effect, whereas larger values of "education" and "health condition except job training" had a negative one. Fourth, in the case of job satisfaction, "female", "joining the labor union" and having a higher "income" or "job security" led to higher satisfaction and a better "health condition compared to an average person". Further, a higher "overall life satisfaction" and "economic level" led to lower job satisfaction. The analysis of the determinants of employment productivity of transportation business and seeking for improvement plan is expected to improve the employment productivity in the transportation business.

• Korean Journal of Construction Engineering and Management
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• v.22 no.2
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• pp.12-20
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• 2021

Unsafe working environments slow down working speed in that it takes a lot of time to respond in case of an accident, greatly reducing the productivity of construction work. Therefore, proper safety management that does not impede the productivity of construction works is a very important factor for successful construction project. However especially in mega project, the mutual effects of safety management and productivity are complex. Therefore, this study establishes a causal model between safety management and productivity influencing factors based on effectiveness metrics, and analyzes the effect of increased site congestion due to excessive personnel input, irregular safety measures and inefficient change of work schedules. The result of this study, is expected to contribute to enhancing the competitiveness of the construction industry as the basis for establishing a safety management plan that can secure appropriate productivity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.771-784
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• 2009

In the situation where the uncertainty of the environment of organizations is high and dynamic, the competitive advantage should be secured and maintained through securing knowledge-based intangible assets rather than tangible assets. human resources management in the service industry is more important than in any other industries. Accordingly, based on preceding researches, this study examines the adoption factors and the results of organizations with regard to the e-HRM system as IT-based information system. The proof results are summarized as follows. First, the degree of IS maturity in the information technology factors was found to have effects on the business results of organizations (financial and non-financial results) and the IS/IT based structure was found to have significant effects on financial results (productivity, growth potential) but no effects on non-financial results (revitalization of organizations, the degree of total satisfaction). Second, the degree of competition, the degree of information technology and environmental uncertainty factors in environmental factors were found to have effects on financial results (productivity, growth potential) but no effects on non-financial results (the revitalization of organizations, the degree of total satisfaction). Third, it can be seen that the scales of organizations partially play the adjustment role between information technology factors and environmental factors and the business results of organizations. Based on these results, we can cautiously draw the conclusion that it is effective in enhancing financial results (productivity, growth potential) of organizations to adopt the e-HRM system in the case of large scale organizations in the service industry.

• Journal of Korean Society of Forest Science
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• v.97 no.2
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• pp.135-139
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• 2008

Seed production and germination could be influenced by some factors. The picking time and climate factors are regarded as the elements to obtain sound seeds. We have observed the seed productivity and germination of seeds from trees of Chamaecyparis obtusa selected in a clonal seed orchard. Depending on picking time, various shapes from liquid material, something jellied to the fully matured one were observed. Germination aspects varied throughout the test days. After 20days of seeding in a glass petri-dish, germinal apparatuses appeared from the all seeds which had been picked from after at the end of August. The highest germination rate of about 30% was observed from the seeds picked from $20^{th}$ of September and $10^{th}$ of October. Seed production was about two times higher in 2005 than in 2006 and the average germination rate was also higher in 2005. We have also analyzed the effects of climatic factors about two consecutive years on seed productivity. Among the climatic factors, monthly sum of temperature and of precipitation were the main factors for maturation of Chamaecyparis obtusa seeds.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.591-600
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• 1993

Considerable controversy exists about the trend of animal traction effects on crop production in dryland farming systems in sub-Saharan Africa (SSA). This problem arises on account of the failure of the few available empirical studies to recognise the important of technological experience of the individual adopting farmers. This study hence addresses this issue by examining the effects of experience in animal traction technology (ATT) on farm size, cropping emphasis, total crop output and farm productivity. It is based on farm management survey data on 42 small holder farm households fro Ghana. Thirty of these households used animal traction technology (ATT) fro crop cultivation and the rest, mainly hand-hoe. The animal traction sub-sample is classified into three groups according to farmers' years of experience with the technology , thus , those with 1-2, 3-10, and more than 10. Evidence from the study shows that the progression of years of experience with ATT leads to inten ification of labour and land use systems, enhancement of degree of motivation to enter into the market economy, increases in total crop output and farm productivity resulting for decreases in cultivated acreages. The implication of the findings is that institutioal and technical support that do accompany the introduction of such technologies should be structured to last for a relatively longer period to accomodate the learning process.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.725-730
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• 2003

Three recombinant Saccharomyces cerevisiae strains showing different levels of xylose reductase activity were constructed to investigate the effects of xylose reductase activity and glucose feed rate on xylitol production. Conversion of xylose to xylitol is catalyzed by xylose reductase of Pichia stipitis with cofactor NAD(P)H. A two-substrate fermentation strategy has been employed where glucose is used as an energy source for NADPH regeneration and xylose as substrate for xylitol production. All recombinant S. cerevisiae strains Yielded similar specific xylitol productivity, indicating that xylitol production in the recombinant S. cerevisiae was more profoundly affected by the glucose supply and concomitant It generation of cofactor than the xylose reductase activity itself. It was confirmed in a continuous culture that the elevation of the glucose feeding level in the xylose-conversion period enhanced the xylitol productivity in the recombinant S. cerevisiae.