• The Korean Journal of Ecology
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• v.10 no.4
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• pp.175-182
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• 1987

Soybeans(Glycine max Merr. cv. Kwanggyo), inoculated with Rhizobium japonicum 110 and then sand-cultured with nitrate gradients (0, 1, 3, 10 and 30mM KNO3). were studied on the growth analysis, nitrogen fixation and nitrogen economy during the growing period. The maxium values of total leaf area, biomass and nitrogen quantity were increased 139%, 122% and 161%, respectively with higher concentration of nitrate treatment. Nodulation showed significant linear correlation with leaf area growth for each treatment of nitrate concentration increased. The more nitrate concentration increased, the more distribution ratios of dry matter and nitrogen to nodule decreased, and the more T/R ratios, CGR and N content increased. On the other hand, F/C ratios and RGR showed little changes. The amounts of nitrogen fixation of soybean alloted to 0, 1, 3, 10 and 30mM nitrate treatments were 100, 46, 14, 0.1 and 0.004% for the total nitrogen assimilation, respectively. The nitrogen utility of soybean plant was smaller than that of other plants and ranged from 23 to 30 at varying nitrate gradients.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1318-1320
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• 1999

Recently, according to the growth of national economy and the improvement of lining conditions, electric power demand is increasing gradually. So it is being examined to construct large thermal power plants or nuclear plants. For the effective use of lands and for the economy of generations sites, the distance between generation and demand locations becomes farther and farther. At the same time, people desire higher quality or electric power. So in this paper, the optimal modulation controller for HVDC transmission system are designed by a recursive algorithm that determines the state weighting matrix Q of a linear quadratic performance. It means that the application of optimal modulation controller in HVDC transmission system can contribute the propriety to the improvement of the stability in HVDC transmission system.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.179-197
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• 2016

The development of overseas resource is a driving force to secure the energy security in Korea with low sufficiency rate of energy. This paper analyzes the effect of overseas oil resource development on the economy by presenting a real business cycle model with consolidated energy price index. A linear-quadratic dynamic programming is adopted to raise computational transparency and efficiency. The analysis shows that the overseas oil resource development project during 2010 and 2012 decreases the energy price by 1.2% per annum which effect is equivalent to the positive 0.47% to the GDP. The implication calls for steady and robust support for overseas resource development projects to enhance energy resilience.

• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.351-359
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• 2016

The Korean Prototype Gen-IV sodium-cooled fast reactor (PGSFR) is supposed to be loaded with a relatively-costly low-enriched U fuel, while its envisaged transuranic fuels are not available for transmutation. In this work, the U-enrichment reduction by improving the neutron economy is pursued to save the fuel cost. To improve the neutron economy of the core, a new reflector material, PbO, has been introduced to replace the conventional HT9 reflector in the current PGSFR core. Two types of PbO reflectors are considered: one is the conventional pin-type and the other one is an inverted configuration. The inverted PbO reflector design is intended to maximize the PbO volume fraction in the reflector assembly. In addition, the core radial configuration is also modified to maximize the performance of the PbO reflector. For the baseline PGSFR core with several reflector options, the U enrichment requirement has been analyzed and the fuel depletion analysis is performed to derive the equilibrium cycle parameters. The linear reactivity model is used to determine the equilibrium cycle performances of the core. Impacts of the new PbO reflectors are characterized in terms of the cycle length, neutron leakage, radial power distribution, and operational fuel cost.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.381-389
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• 2021

This study aims to examine the effect of strategic planning, human resource management, and asset management on increasing the productivity of the rural economy. This research is a quantitative approach. The research sample was carried out by simple random sampling and data collection using a questionnaire so that 129 respondents were determined. The research test was conducted using multiple linear regression with the OLS (Ordinary Least Square model. The results obtained were that strategic planning, human resource management, and asset management had a significant positive effect on increasing the productivity of the rural economy. This shows that strategic planning is the most important thing in industry, companies, or organizations as a guideline to achieve optimal performance. In addition, human resource management and asset management are positive supports for increasing the economic productivity of rural communities to achieve welfare goals. This research proves that strategic planning must be carried out by considering the existing potential, both sources. natural resources, human resources, and economic resources Meanwhile, human resource management and asset management are mandatory to support the sustainability of an organization or company so that the benefits of the study as study material in strategic decision making, both in business and public policy.

• Hwankyungkyoyuk
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• v.19 no.3
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• pp.67-79
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• 2006

Education for Sustainable Development(ESD) is inclined to become popular topics in EE related debates, almost similar to populism, with declaration of UNESCO's Decade OF ESD (DESD). However we can't avoid that development in ESD practically means economic linear progress. Basically UN's declaration is to accomplish worldly task on human civilization, social & environmental problems, including ESSD. ESD is also important means for practicing ESSD, which has proved to be failure since Brutrant Report, owing to uncertain recognition of sustainability which should be something figured out by their surrounding circumstance or the conditions following its community culture, all same around the world. In this circumstance, we need certain identification on ESD globally recognized, no matter with the developing level of economy. But sustainability is usually managed or controlled by economically powered countries, by improving relatively under-development countries's economic conditions for equity. They believe under-development countries's env. problems can't be resolved without securing of economic equity. Under-development countries's economic equity can be come true ? even by another economic super powers. It really means just controlling or management by them. These all controlling process can't secure under-development countries's sustainability. Because it is not something just controlled, characterized as growing up by self-supporting system of ethnic or regional communities. So identification of sustainability in here is , not . Following its identification, we should discuss ESD, and furthermore for real ESD, there is powerful need to change it into ESE (Education for Sustainability & its Economy) to reflect this co-conceptional approach to ESD. And also we need to distinguish the educational contents boundaries among ESD and EE for this. Basically existing EE has been dealing with pollution-oriented or its related social comprehensive subjects, so it seems that EE is not familiar and harmony with ESD contents, however in alternative case I propose in this paper, changing into ESE, it could include almost all of ESD subjects, furthermore practically EE might be same with ESE.

• Knowledge Management Research
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• v.21 no.4
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• pp.157-173
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• 2020

In accommodation sharing economy, customers take a risk of uncertainty about product quality, which is an important factor affecting users' satisfaction. This risk can be lowered by the information disclosed by the facility provider. Self-presentation of the hosts can make a positive effect on listing performance by eliminating psychological distance through emotional interaction with users. This paper analyzed the self-presentation text provided by Airbnb hosts and found key aspects in the text. In order to extract the aspects from the text, host descriptions were separated into sentences and applied the Attention-Based Aspect Extraction method, an unsupervised neural attention model. Then, we investigated the relationship between aspects in the host description and the listing performance via linear regression models. In order to compare their impact between the three facility types(Entire home/apt, Private rooms, and Shared rooms), the interaction effects between the facility types and the aspect summaries were included in the model. We found that specific aspects had positive effects on the performance for each facility type, and provided implication on the marketing strategy to maximize the performance of the shared economy.

• Korea Trade Review
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• v.42 no.2
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• pp.277-296
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• 2017

More than 95% of imports and exports in the World are being transported by vessels. In other words, marine transportation accounts for a large portion of share in the world trade. The purpose of this study is to analyze factors of seaborne trade volume according to items affecting on the world economy. This study conducted a linear regression analysis between seaborne trade volume and the world economy (world GDP) to estimate the correlation between them. Panel data analysis and random effects model analysis have been applied to examine the effect of seaborne trade volume. For this study, the seaborne trade volume is categorized into 10 items, and estimated how much global GDP will be affected when the trade volume changes. In addition, the granger causality test was conducted to verify the relationship between seaborne trade volume and the world GDP. As a result, seaborne trade volume and the world GDP were mutually influenced each other. However, seaborne trade volume affects the world economy more significantly. The items affecting world economic growth include petroleum products, crude oil, chemical products, and so on. The estimated value of the coefficients of petroleum products, crude oil and chemical products were 1.014, 1.013 and 1.010, respectively. The estimated value 1.014 of petroleum products means that the growth rate is 1.014 times higher than the current world GDP growth rate when the seaborne trade volume of petroleum products increased by one unit Lastly, this study examines the seaborne trade volume of 10 categories and then verifies whether the growth rate of world GDP will increase when the volume of seaborne trade increased. This study is expected to provide policy-makers with useful information about formulating policies related to international trade.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.29-36
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• 2016

Lifting lugs are frequently used to transport and to turn over blocks of ship and offshore structures in a shipyard. As the shipbuilding technology has been developed, blocks has become bigger and bigger, and block management technology takes a more important role in shipbuilding to enhance the productivity. For the sake of economy as well as safety in design of lug structure, needed is a more rational design procedure based on the ultimate strength derived through the rigorous non-linear structural analysis considering both the material and geometric non-linearity. This study is aimed at deriving the optimum design of T type lug structure which is frequently used in a shipyard. The optimum thickness of lug's main body is to be determined based on the results of non-linear strength analysis. As far as the present results for T type lugs having various capacity are concerned, it can be said that the present optimum design result can guarantee both safety and economy. From the fact that any regular trend cannot be found in weight reduction to the capacity of lugs, it seems to be necessary to review the current design procedure of lug structure. The present design procedure can be extensively used in design of various types of lug structures used in shipyard.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.449-456
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• 2002

The objective of this study was to optimize medium composition of initial pH, tryptone, glucose, yeast extract, and mineral mixture for production of bacteriocin by Lactobacillus acidophilus ATCC 4356, using response surface methodology. A response surface approach including new statistical and plotting methods was employed for design and analysis of the experiment. An interiorly augmented central composite design was used as an experimental design. A normal-distribution log-link generalized linear model based on a subset fourth-order polynomial ($R^2$=0.94, Mean Error Deviance=0.0065) was used as an analysis model. This model was statistically superior to the full second-order polynomial-based generalized linear model ($R^2$=0.80, Mean Error Deviance=0.0140). Nonlinear programming determined the optimum composition of the medium as initial pH 6.35, typtone $1.21\%$, glucose $0.9\%$, yeast extract $0.65\%$, and mineral mixture $1.17\%$. A validation experiment confirmed that the optimized medium was comparable to the MRS medium in bacteriocin production, having the advantage of economy and practicality.