• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.3
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• pp.15-25
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• 2019

The study was conducted to compare the chemical properties and microbial activity of soil and the crop productivity by applying homemade liquid fertilizers (LF) used in leading cucumber farms as well as to evaluate the eco-friendly LFs to substitute for a chemical fertilizer. Three homemade LFs, EM, starfish, and native microbes, and a chemical LF were regularly fertigated per three days during the growing season. Chemical LF contained the highest pH, EC (electrical conductivity), and concentrations of T-N, $P_2O_5$, K, Ca, and Mg, while the lowest EC level was observed for EM LF. Soil EC was the highest to the 3.0 dS/m for chemical LF-plots, with lowering soil pH, OM (organic matter), and Mg concentration. Soil chemical properties mostly increased in native microbes LF-plots. However, soil microbial properties were not significantly different among the LF treatment plots. OTU (operational taxonomic units), richness estimator, and diversity index of bacteria and fungi increased in the chemical LF and EM LF based on the pyrosequencing analysis. SPAD and PS II values on the treated-cucumber leaves were seasonally decreased from 32 to 60 days after transplanting, with the rapid decline observed at 45 days after transplanting. Number of leaves and crop height increased in the treatments with EM and native microbes LF. LF treated-cucumber crops were not significantly different for total fresh weight and fruit yield.

• Journal of the Korean Society for Environmental Technology
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• v.19 no.6
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• pp.550-555
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• 2018

International Maritime Organization (IMO) is one of the most effective organizations in evolving international law for the protection and conservation of the marine environment. The IMO, MARPOL(Marine Pollution) 73/78 contains six Annexes that provide an overarching framework for the objectives of the international marine pollution. Annex IV was regulated by 64 th resolution in 2012 to control sea pollution from sewage. In 2014 large-scale wastewater treatment and nutrient removal device was developed with a grant from the Ministry of Oceans and Fisheries. A combined new process of Sequence Batch Reactor (SBR) and Membrane Bioreactor(MBR) was developed to overcome the pollution caused by shipboard sewage. In the present study, shipboard sewage wastewater was treated by mixing and aeration cycle in the newly developed SBR process. Furthermore, during analysis by NGS technique(Macrogen Co., Ltd.), dominant species of bacteria were found in the aeration tank of the Bench-scale wastewater treatment facility. Bacteroidetes and Gammaproteobacteria accounted for 27.1 % of the aerobicbacteria and 16.8 % of the anaerobicbacteria, respectively. Microorganisms play a vital role in shipboard wastewater treatment. A further detailed study is required to understand the precise role of the microorganisms in the wastewater treatment.

• Maritime Security
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• v.2 no.1
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• pp.1-42
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• 2021

Controversy continues over the offensive nature of China's naval strategy to become a maritime power. Therefore, the purpose of this study is to identify the characteristics of China's naval strategy to become a maritime power by using the three elements of strategy and predict China's military actions in the future. For this purpose, research was conducted by considering the three elements of strategy and the distinct characteristics of naval strategy, and it was found that China's naval strategy was overall aggressive, but there was an imbalance in the pursuit of aggression between each strategic element. Offensive nature was prominent in terms of the methods, but there were limitations in the goals and means, such as the need to cooperate with neighboring countries to become a maritime power and the lack of military technology and operational continuity. The prospects for China's future military actions derived from the imbalance between these strategic elements are as follows. ① The risk of all-out military conflict with the US is low for now. ② China may use its naval power to force or cause limited military clashes against neighboring countries within the first island chain. ③ Accidental military conflicts with the US and neighboring countries may occur over naval confrontation over territorial disputes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.766-773
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• 2021

Chemicals, such as ammunition, are disposable items that cannot be reused because of their operational characteristics. The reliability of the test process and test results are important factors in evaluating the performance of guns and ammunition. The pressure after firing is a crucial value in an acceptance test of guns and ammunition performance; hence, accurate measurements are required. The pressure in the artillery is measured using the copper crusher gauge. The compression amount of copper is converted into a pressure by either a length-pressure conversion table or conversion formula. Therefore, the exact measurement of the squeeze of the copper crusher is related directly to the correct estimate of the pressure. Currently, the pressure is measured manually by the operator, which always includes some human error. In this study, the cause of the measurement error was analyzed, and the automatic measuring system for copper crusher deformation was developed to minimize the error elements. A copper crusher could be measured using the probe sensor and CCD camera, and the Jig for stable positioning was also designed. A designated SW was also developed for the system operating and measurement-analysis. This measuring system through this study may be used for an ammunition stockpile reliability test and gun/ammunition acceptance test.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.541-549
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• 2020

This study conducts differential analysis on the financial positions of Korean shipping companies before and after the bankruptcy of the H carrier, looking specifically at their financial ratios, profit and loss patterns, and other factors related to their financial operation. Firstly, it was discovered that major measures of financial health, such as average assets per carrier, were not affected by the bankruptcy of the H carrier. However, despite this, most carriers experienced large changes in profits and losses, with total sales and shipping revenues averaging 424.5 billion won and 381.7 billion won respectively before the bankruptcy, but falling by half to 252.1 billion won and 234.6 billion won after the bankruptcy. Additionally, charter revenues and expenses also dropped by more than half. EBIT/sales and pre-tax revenue margins were also heavily affected after the bankruptcy, with both figures averaging 8% and 3% respectively before the bankruptcy, but falling into the negative range at -2% and -8% post-bankruptcy, resulting in significant deterioration in operational profitability. The study concludes that there is an urgent need to establish a global sales network, improve cost structures, and consistently secure stable cargo in order to increase Korean carriers' profitability. Of all financial measures, liquidity and total asset efficiency were identified as the most severely-impacted by the H carrier bankruptcy, thereby requiring the most pressing policy addressing.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.443-452
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• 2021

The authors obtained the discrete hedging rule for a reservoir's water supply operation by applying mixed-integer programming to save more water by earlier rationing of water supply for a drought period. The 'water supply adjustment guide' is the current operational method applied to the multipurpose reservoirs, and it was derived by a simulation method. Applying the two rules to the Hapcheon multipurpose dam's reservoir simulations with the inflow record from 2003 to 2018, the water supply deficit occurred for the long drought from 2015 to 2018. Especially, the no water supply or intermittent water supply persisted for the second half of 2017. The water supply adjustment guide had the 'normal water supply recovery threshold on storage,' which resulted in the water supply being unavailable in July 2017; then, the water supply suspension occurred until January 2018, when the reservoir storage was greater than the normal water supply recovery threshold. Despite the storage increasing due to the inflow of water into the reservoir, the suspension occurrence needs to be improved in practice. The current water supply adjustment guide and the discrete hedging rule for a reservoir's water supply operation are useful and realistic as the reservoir operation guide, which shows the concept of reducing water supply during the drought phase as scientific figures. However, to improve the reservoir simulation results, which do not provide any or intermittent water for several months, it is necessary to increase the current water supply reduction for drought phases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.116-126
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• 2021

Ground Component Command (GCC) has been developing operational planning and execution systems to implement "Decisive Integrated Operations", which is the concept of ground operations execution, and achieved remarkable results. In particular, "Simultaneous Offense-Defense Integrated Operations" is developed mainly to neutralize enemies in deep areas and develop favorable conditions for the allies early by simultaneously attacking and defending from the beginning of the war. On the other hand, it is limited to providing scientific and reasonable support for the commander's decision-making process because analyzing the effects of the deep operation with existing M&S systems is impossible. This study developed a model for analyzing the effects of deep operations that can be used in the KJCCS. Previous research was conducted on the effects of surveillance, physical strike, and non-physical strike, which are components of deep operations to find the characteristics and limitations and suggest a research direction. A methodology for analyzing the effects of deep operations reflecting the interactions of components using data was then developed by the GCC, and input data for each field was calculated through combat experiments and a literature review. Finally, the Deep operations Effect CAlculating Model(DECAM) was developed and distributed to the GCC and Corps battle staff during the ROK-US Combined Exercise. Through this study, the effectiveness of the methodology and the developed model were confirmed and contribute to the development of the GCC and Corps' abilities to perform deep operations.

• Journal of agriculture & life science
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• v.51 no.4
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• pp.139-147
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• 2017

This study was carried out in order to reduce the amount of sawdust for recycling the generated manure from livestock farms, and to investigate the effects on the reducing usage of sawdust and quality of produced compost. To do this, a cylindrical horizontal composting device were used in the experiments and compost was analyzed for judging produce compost quality. The experiment was carried out separately under different cases of operational control conditions. The first case was produced by using sawdust and pig manure mixture(Test-1); the second case was produced by using sawdust, pig manure and the previously produced compost(Test-2). In the second case, Except for some heavy metal content, The water content and C/N ratio were found to be suitable for fertilizer process specification of the RDA(Rural Development Administration) and it was found to reduce the sawdust 1.25tons usage.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.32 no.1
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• pp.171-197
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• 2021

The purpose of this study is to suggest the ways of improving systematic records management based on the results of analyzing the present records management situation of college and department in an university which is operating archives. To achieve the purpose, survey and interview of the persons in charge of producing and managing the administrative documents of college and department were conducted. Furthermore, actual condition investigation of records management of college and department and university archives were analyzed. According to the results of analysis, the following problems were found: 1) lack of sufficient records management by college and department, 2) lack of understanding of tasks by processing staffs, 3) operational problems of university archives. Based on the results, recommendations were made as follows; First, it is necessary to improve an awareness of records management by operating staffs. Second, it is necessary to educate staffs through the development of training programs reflecting the characteristics of the university and set up guidelines for records management by college and department. Third, it is necessary to execute reorganization and supplement the personnel of university archives.

• Journal of Navigation and Port Research
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• v.45 no.1
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• pp.1-8
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• 2021

The purpose of this study was to explore the regulations and operational problems of on-board training, and to investigate and analyze the satisfaction level of consignment on-board training among students who completed their training at Korea Maritime & Ocean University. In terms of satisfaction differences by gender, female students generally had a higher relative satisfaction level than male students. The different types of satisfaction in the navigation and engineering categories, the overall practical effect and satisfaction level of the training records shows that the satisfaction level of the trainee is much lower than that of the trainee, so relevant educational institutions and shipping companies need to take measures to improve the satisfaction level of this part. The most important part of the comprehensive company evaluation completed by trainees asked whether they thought the training was equivalent in labor to the employees. Results suggest shipping companies must make a clear distinction between employees and trainees, while establishing relevant internal procedures so that the on-board training process can be carried out in accordance with the purpose of the on-board training consignment.