• Environmental and Resource Economics Review
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• v.15 no.4
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• pp.693-712
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• 2006

A pre-feasibility test is done for renewable energy hybrid power systems at off~grid islands in which the current power supply is provided only by diesel generation. We apply Homer (Hybrid Optimization Model for Electric Renewables) which was developed by the National Renewable Energy Laboratory (NREL) for the analysis to identify the cost-minimizing combination of power generating facilities for the given load profiles. Chuja-Do, Geomun-Do and Youngsan-Do have been selected for our analysis considering the wind resources data of the Korea Institute of Energy Research (KIER). Information on wind speed, solar radiation and temperature is also used for the analysis. System component cost information from overseas market has been used due to the lack of domestic information. Site specific Load profile for electricity demand for those islands are reconstructed based on the partial survey results obtained form other sources. The LCOE of the least cost hybrid power systems for Chuja-Do, Geomun-Do and Youngsan-Do are $0.278/kWh, $0.234/kWh and $0.353/kWh, respectively Considering the fact that diesel generation is being subsidized at the price of $0.300/kWh by the government, first 2 cases are economically feasible for the introduction of renewable energy hybrid systems to those islands. But the third case of Youngsan-Do does not meet the criteria. The basic differences of these pre-feasibility test results are from the differences of the site specific renewable energy conditions, especially wind resources. In summary, promoting hybrid systems in the off-grid remote island should be based on the economic feasibility test results. Not all the off-grid islands are feasible for introducing this renewable energy hybrid system.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.67-74
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• 2008

Because the fire service demands are increasing and forms are diversified, the first thing you must do is to make up the fire service budget to keep fire service power sufficiently. Such budget allocation leads to supply enough fire service people want and results in social welfare satisfaction. If the budget of fire service is not enough to meet with its power, sufficient security of the fire fighters would be impossible. Also, when the urgent disasters occur, the government cannot cope with them effectively. In fact, loss of many lives and properties took place in some cities and kuns because of that. The purpose of this study is to investigate the influence of fire service budget for fire service force. To do this, this study reviews fire service budget, fire service force. And this study sets up three hypotheses based on the theoretical backgrounds and the past research. The statistical method used for the verification of hypotheses is multiple regression analysis. The analysis showed that fire service budget per head variable was positive significant, fire service budget ratio variable was not significant. Also, public facilities tax variable was negative significant. Therefore, the analysis showed that public facilities tax couldn't fill the role as a earmarked tax.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.65-70
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• 2013

In many cases, operation of regional trunk lines is not profitable to railway operators. Nevertheless, railway operators are under pressure to manage regional trunk lines running under deficits, to better serve public interests. Given this situation, railway operators need to optimize assets by adjusting train schedules or changing the number of trains running. When railway operators judge the operation of a regional trunk line, the B/C ratio is generally used as a management index. This ratio is not considered part of strategic operational policy over the long term, and excessively influenced by the aspects of supply and demand over the short term. Accordingly, this study focused on indices that might be used to prevent worsening deficits and provide long term strategic operation policies, main indices to better measure economic situations, and auxiliary indices to supplement the main index. The main indices were measured in conventional ways to target experts and employees. This study presents quantitative standards, which are intended to be used to create itemized criteria through an Analytic Hierarchy Process, for better decision-making.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.276-284
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• 1993

The ABB-CE System-80 reactor power cutback system(RPCS) is designed to enable continuous operation of the reactor without trip in the events of the loss of one of the two main feedwater pumps and loss of load, and thus improves plant availability in a cost effective manner. In this study expansion of RPCS has been investigated for continuous reactor operation without trip in the event of an inward control element assembly(CEA) deviation including a single rod drop. Under the expanded function of RPCS the control system will provide a rapid core power reduction on demand by releasing CEAs to drop into the core and reduce the turbine power, if necessary, to follow the reactor power variation. This design feature which is included as the new design features to be incorporated in the ABB-CE System-80+ meets the EPRI advanced light water reactor(ALWR) requirements. For this study core analysis models of System-80+ have been developed to simulate the nuclear steam supply system(NSSS) response as well as the RPCS initiation of rapid CEA insertion. The results of this study demonstrate that the reactor trip can be avoided in the event of inward CEA deviation including a single rod drop by the RPCS initiation and thus the plant availability and capacity factor would be increased.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.9-17
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• 2017

The opening of public data has been perceived as a critical factor in deciding a country's rise or fall. Since the global economic crisis, countries around the globe have expanded the supply of public data as a new growth engine to create significant economic effects. As a result, there has been a rising demand for a study on the influence of public data in the private sectors. This study attempted to achieve the following objectives. First, the effects of independent variables-system quality, information quality, information security, social influence, innovation and assistance by the public organization- on the intention to use the public data was examined. Second, the effects of the mediating variables - Perceived Ease of Use (PEU) and Perceived Usefulness (PU) - on the independent variables and intention to use (dependent variable) were investigated. Third, after selecting utilization type, frequency of public data usage and frequency of occupational & e-government service usage as moderating variables, their effects on the relationship between the independent variables and dependent variable (intention to use them in the private sector) were studied. It is expected that the study results would be useful in developing strategies aimed to utilize public data in the private sectors.

• Membrane Journal
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• v.30 no.3
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• pp.173-180
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• 2020

As the demand for fossil fuels continues to increase worldwide, carbon dioxide (CO₂) concentration in the air has increased over the centuries. The way to reduce CO₂ emissions to the atmosphere, carbon capture and sequestration (CCS) technology have been developed that can be applied to power plants and factories, which are primary emission sources. According to the climate change mitigation policy, direct air capture (DAC) in air, referred to as "negative emission" technology, has a low CO₂ concentration of 0.04%, so it is focused on adsorbent research, unlike conventional CCS technology. In the DAC field, chemical adsorbents using CO₂ absorption, solid absorbents, amine-functionalized materials, and ion exchange resins have been studied. Since the absorbent-based technology requires a high-temperature heat treatment process according to the absorbent regeneration, the membrane-based CO₂ capture system has a great potential Membrane-based system is also expected for indoor CO₂ ventilation systems and immediate CO₂ supply to smart farming systems. CO₂ capture efficiency should be improved through efficient process design and material performance improvement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.1-9
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• 2014

Recently, natural aggregate was adequate to supply the demand due to increase of building construction. National pollution induced by construction waste caused by the reconstruction and redevelopment was cited as the major social issues in Korea. Therefore, government are required by law to use the recycled aggregate. In order to consider safety, KS F 2573 recommend that recycled aggregate with below design strength 27MPa and replacement ratio of 30%. This study on flexural behaviors of reinforced concrete beam was conducted and the specimens employed in test were planed with high strength concrete (40, 50 and 60MPa) and recycled aggregate replacement ratio (0, 30, 50, 100%). Although the flexural strength of reinforced concrete beam has trendy to decrease with increase of replacement ratio, it is meet to KCI 2007. The comparison results show that reinforced concrete beam using recycled aggregate can apply as flexural member in building construction.

• Korean Journal of Construction Engineering and Management
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• v.9 no.4
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• pp.173-181
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• 2008

Last decade, Korea's export scale has resulted in remarkably increasing tendency, and the Korean construction firms(KCFs)' activities on the global markets also have been revitalized. Therefore, this paper analyze a correlation between changes in the oversee market conditions and firms' competitiveness focused on plant business. The aim of this paper is to analyze the internal competency change of the KCFs on the global markets in the past 5 years and to find gap of internal competencies between KCFs and outstanding foreign firms. From a survey analysis this paper found that the external impacts on the global markets(changes of exchange rates, raw materials prices, supply-demand conditions, etc.) have highly influenced the sales amount of the KCFs. But the impacts to change the operating profit have been analyzed as not important. So it is necessary to reinforce the KCF's internal competencies rater than expecting an improvement of the external conditions. Also, the KCFs should strengthen the design engineering as a core competency.

• Journal of agriculture & life science
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• v.52 no.6
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• pp.27-36
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• 2018

Recently, the demand for new cultivar of oriental mustard(Brassica juncea) is increased as the consumption of oriental mustard has increased dramatically in the market due to Kimchi is attracting the world's attention. However, absence of seed supply system can cause many problems including inbreeding depression due to self seed production, deterioration of the seed purity and heterogeneity of commercial seed. To establish the $F_1$ variety breeding system of oriental mustard, pure line and inbred lines were screened from inbreeding genetic resources. Male-sterile line was also selected from breeding combinations for the quality improvement of mustard. The combining ability from(Indojasai ${\times}$ Goheungdamyang) combinations and isolation line of(MS910 ${\times}$ Japan red mustard 8 ${\times}$ Ganghwa mustard 9) was highest, thus these lines were selected as parental lines. PCR(Polymerase Chain Reaction) and gene sequence analysis revealed that the genes related to CMS(orf263, orf220, and orf288) were distributed in mitochondria. The isolated lines from this study also showed good performance in yield test and farmhouse prove test.

• Journal of the Korea Society for Simulation
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• v.31 no.1
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• pp.29-41
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• 2022

As one of the alternatives to solve the problem of unstable food supply and demand imbalance caused by abnormal climate change, the need for plant factories is increasing. Airflow in plant factory is recognized as one of important factor of plant which influence transpiration and heat transfer. On the other hand, Digital Twin (DT) is getting attention as a means of providing various services that are impossible only with the real system by replicating the real system in the virtual world. This study aimed to develop a digital twin model for airflow prediction that can predict airflow in various situations by applying the concept of digital twin to a plant factory in operation. To this end, first, the mathematical formalism of the digital twin model for airflow analysis in plant factories is presented, and based on this, the information necessary for airflow prediction modeling of a plant factory in operation is specified. Then, the shape of the plant factory is implemented in CAD and the DT model is developed by combining the computational fluid dynamics (CFD) components for airflow behavior analysis. Finally, the DT model for high-accuracy airflow prediction is completed through the validation of the model and the machine learning-based calibration process by comparing the simulation analysis result of the DT model with the actual airflow value collected from the plant factory.