• Journal of Wetlands Research
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• v.23 no.1
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• pp.60-66
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• 2021

As the concentration of nitrogen in the sewage flowing into the sewage treatment plant increases due to urbanization and industrialization, the degree of adverse effects such as eutrophication and toxicity to the aquatic ecosystem is also increasing. In order to treat sewage containing high concentration of nitrogen, various studies on the biological nitrogen removal process are being conducted. Existing biological nitrogen removal processes require significant costs for supplying oxygen and supplementing external carbon sources. In this respect, as a high-level nitrogen removal process with economic improvement is required, an anaerobic ammonium oxidation process (ANAMMOX), which is more efficient and economical than the existing nitrification and denitrification processes, has been proposed. The purpose of this study is to confirm the stability of the ANAMMOX process in the water treatment process and to derive the ratio of ammonia nitrogen (NH4+) to nitrite nitrogen (NO2-) for the implementation of the mainstream ANAMMOX process. A laboratory-scale Mainstream ANAMMOX reactor was operated by applying the ratio calculated based on the substrate ratio suggested in the previous study. In the initial range, the removal efficiency of NH4+ was 58~86%, and the average removal efficiency was 70%. In the advanced range, the removal efficiency of NH4+ was 94~99%, and the average removal efficiency was 95%. As a result of the study, as the NH4+/NO2- ratio increased, the stability of the mainstream ANAMMOX process was secured, and it was confirmed that the NH4+ removal efficiency and the total nitrogen (TN) removal efficiency increased. As a result, the results of this study are expected to be used as basic data in the application of the ANAMMOX process in the mainstream.

• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.546-558
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• 2020

While industrialization has provided in abundance, the pollution it creates has caused untold damage to the environment, increasing the frequency and severity of natural disasters through changes in global climate patterns. The World Risk Forum's (WEF) World Risk Report presented the results of a survey of experts from around the world detailing the most influential risk factors over the next decade. Notably, the failure to respond to climate change ranked first and the global water crisis third. The extreme drought in the western Chungnam province was unexpected in 2016. At the time, the water level of Boryeong Dam was drastically decreased due to receiving less than half the average recorded rainfall in the region that year. The Boryeong Dam diversion pipeline has the capacity to solve the water shortage problem between these two regions by providing water from Geumgang to the western part of Chungnam, including Boryeong City. Current weather trends suggest drought is likely to continue in western Chungnam, which uses the Boryeong Dam as an intake source. This makes it necessary to operate Boryeong Dam diversion pipeline in an efficient and effective manner. SWAT is a watershed scale model developed to predict the impact of land management practices on water. The SWAT model was used in this study to evaluate the adequacy of the Boryeong Dam diversion pipeline operational plan by comparing it to present Boryeong Dam diversion pipeline operation. By investigating the number of days required to reach each reservoir stage, we determined that the number of days required to reach the boundary stage was less than that of the current operation. This determination accounts for the caveats that the Boryeong Dam waterway was not operated and only one pump will be operated from October to May of next year. As our results suggest, the most stable operation scenario is to operate two pumps at all times. This can be accomplished by operating two pumps from the caution stage to increase the number of pumps whenever the stage is raised. In addition to the stable operation of the Boryeong Dam pipeline, policy considerations are required with regard to imposing a water use charge on users of the Boryeong Dam region.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.27-34
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• 2021

In this study, the main influencing factors of the occurrence of cyanobacteria at each of the eight Multifunctional weirs were derived using a random forest, and a categorical prediction model based on a Algal bloom warning system was developed. As a result of examining the importance of variables in the random forest, it was found that the upstream points were directly affected by weir operation during the occurrence of cyanobacteria. This means that cyanobacteria can be managed through efficient security management. DO and E.C were indicated as major influencers in midstream. The midstream section is a section where large-scale industrial complexes such as Gumi and Gimcheon are concentrated as well as the emissions of basic environmental facilities have a great influence. During the period of heatwave and drought, E.C increases along with the discharge of environmental facilities discharged from the basin, which promotes the outbreak of cyanobacteria. Those monitoring sites located in the middle and lower streams are areas that are most affected by heat waves and droughts, and therefore require preemptive management in preparation for the outbreak of cyanobacteria caused by drought in summer. Through this study, the characteristics of cyanobacteria at each point were analyzed. It can provide basic data for policy decision-making for customized cyanobacteria management.

• Journal of Korea Port Economic Association
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• v.37 no.3
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• pp.35-53
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• 2021

Over the past 20 years, Korea's number of international passengers and freight transportation records has increased by 8.6% per year, respectively. However, despite the development of sea lanes and increased voyages, there have been constant calls for improving the inefficient management of international passenger ports. Hence, this paper presents improvements and further directions for international passenger port management. Focusing on the Incheon International passenger port as a representative case study, the main results show that the most important, urgent, possible measures for improving the port management include (i) the expansion of customs personnel and implementation of a 24-hours customs clearance system in operation, (ii) installation of buffer facilities between the ferry and ferry cargo and establishment of hinterland specialized in car ferry freight in a facility, and (iii) clear standards for cost-bearing subjects and limitation of high cost related to terminal use in institution. These results imply the need for government policy access and investment reflecting stakeholder opinions at various levels, such as operation, facilities, institution, and so forth, for efficient management of international passenger ports.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.171-182
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• 2022

The habitat degradation caused by large-scale reclamation leads to devastating impacts, such as fine sediment and mud shrimp Upogebia major settlement on Manila clam Ruditapes philippinarum aquaculture in the eastern Cheonsu Bay tidal flats, Republic of Korea. Despite these impacts, there is a lack of studies on the influence of fine sediments on tidal flats that constitute key mud shrimp habitats. This study provides information on the seawater-sediment environment and the influence of dissolved inorganic nitrogen (DIN) fluctuations depending on mud shrimp burrow hole density. Additionally, it discusses countermeasures for Manila clam habitat management. The results show that mean DIN effluxes in areas with a high-density of burrow holes were up to 4 times (0.12 mmol m^-2 d^-1) higher than those in sites of low-density (0.03 mmol m^-2 d^-1) within the Saho and Songhak-ri tidal flats. To manage interference within the competition zone of Songhak-ri tidal flat, it is important to utilize the settlements of spawning season in all three dimensions. Consequently, additional studies in other tidal flats are essential and research in zones where mud shrimps and juvenile clams coexist will help to determine the priorities in the efficient management of clam aquaculture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.517-529
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• 2021

This study analyzes changes in the efficiency of the Department of Early Childhood Education in Korea to examine the effectiveness of the National Evaluation for Teacher Education Institution. We provide policy implications from exploring factors influencing efficiency and comparing characteristics of efficient and inefficient departments. With 149 Department of Early Childhood Education in Korea, DEA was conducted to estimate the relative efficiency, and the Tobit model was applied to explore factors affecting efficiency. The results confirm that the Department of Early Childhood in Korea is run efficiently, though there was no change in scale efficiency and relative efficiency after the two phases of the National Evaluation for Teacher Education Institution. The results show the number of books per student was significantly lower despite a significantly higher employment rate. Efficiency of college departments, department greater than 60 (per cohort), and department in metropolitan city (except Seoul area) is confirmed greater. These results provide policy implications on developing evaluation measure and processes to improve education quality and efficiency.

• Journal of Korea Entertainment Industry Association
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• v.15 no.5
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• pp.189-204
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• 2021

The purpose of this study was to determine the present state of disabled people participating fully in sports for all, analyze its legal, organizational, and policy status, and present a future direction for parasports in pursuit of better sports welfare. For this purpose, literature review was performed, obtaining the following results concerning a parasports activation plan. First, it is necessary to increase large-scale, systematic public relations through association between the government and private organizations with the objective of increasing the number of disabled people participating fully in sports for all. Second, it is necessary to implement full revision of the Sport Promotion Act and establishment of a Parasports Promotion Act actively. Thorough preparation for legislation is most of all required to meet the realities and cope with temporal changes. Third, it is necessary to build an effective system through convergent governance of parasports and relevant ministry. It is necessary to clarify the dual concepts of 'physical activity' and 'sports for all,' present a proper direction for policies, and implement efficient policies and projects. Fourth, it is necessary to reinforce participation by diverse expert groups in the development of parasports policies. This requires convergence of such elements as philosophy, rehabilitation, education, marketing, and laws in addition to sport elements.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.4
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• pp.343-350
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• 2022

The computerization project for underground facilities in Korea began in earnest after the city gas explosion in Seoul in 1994, and the Daegu subway explosion in 1995. As such a large-scale gas explosion accident caused enormous economic loss including human casualties and potential benefits, the need for computerized for efficient management of underground facilities was greatly emphasized in society. Meantime, computerization of underground facilities has been carried out according to the basic plan for building national geographic information system. In this study, problems were identified based on the current status of construction and management of underground facility information, as well as laws and regulations, and directions for establishing quality standards were presented. In addition, construction work standards such as 「Public Survey Work Regulations」, design standards, standard specifications, and technical specifications, gas technology standards, design standards, and communication works so that underground facility information can be linked and utilized in construction work by examining the linkage of the underground facilities, the targets that can be used for quality level information on underground facilities were derived, and a proposal to revise the construction standards was presented. In the future, if the quality standards are established, it is expected that the accuracy and utilization in the construction field will be increased.

• Korean Journal of Plant Resources
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• v.35 no.4
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• pp.502-507
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• 2022

In the present study, plant regeneration through adventitious shoot formation from hypocotyl segments of in vitro seedlings of groundcherry (Physalis angulata L.) was investigated to determine the optimum culture conditions for highly efficient regeneration of the species. Adventitious shoots in hypocotyl segments were efficiently induced on MS media with low concentrations of BAP, specifically, with 0.5-1.0 mg/L BAP singly or in combination with 0.1-0.5 mg/L NAA. The 1.0 mg/L BAP single treatment was most effective for forming multiple adventitious shoots. When the induced shoots were transferred to the root induction media, low concentrations of NAA, IBA, and IAA enhanced the development of adventitious roots from adventitious shoots, suggesting that low concentrations of auxins were optimal for producing regenerated plantlets. The number of roots per shoot was large (> 2.0), and the root length exceeded 8.0 cm. In particular, the development and the overall shape of the roots were ideal. Furthermore, the number and length of shoots exceeded 2 and 6.0 cm, respectively. When the regenerated plantlets were transferred to compost soil, the root and shoot systems had developed well to the point that all of the regenerated plantlets acclimated successfully, resulting in normal morphology and growth characteristics, similar to those of the mother plant. Therefore, plant regeneration via adventitious shoot formation is expected to be one of the main methods for producing groundcherry on a large scale for a stable supply of the raw materials.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.469-475
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• 2022

As the recent structure construction is constructed as a large-scale and deep underground excavation in close proximity to the building, the installation of retaining wall and supporters (Struts) has become complicated, and the number of supporters to avoid interference of the structural slab has increased. This construction process becomes a factor that causes an increase in construction joints of a structure, leakage and an increase in wall cracks. In addition, this reduced the durability and workability of the structure and led to an increase in the construction period. This study planned to dismantle the two struts simultaneously as a plan to reduce the construction joints, and corrected the earth pressure by assuming the reaction force value by the initial earth pressure and the measured data as the response ratio. After recalculating the corrected earth pressure through the iterative trial method, it was verified by numerical analysis that simultaneous disassembly of the two struts was possible. As a result of numerical analysis applying the final corrected earth pressure, the measured value for the design reaction force was found to be up to 197%. It was analyzed that this was due to the effect of grouting on the ground and some underestimation of the ground characteristics during design. Based on the result of calculating the corrected earth pressure in consideration of the response ratio performed in this study, it was proved analytically that the improvement of the brace dismantling process is possible. In addition, it was considered that the overall construction period could be shortened by reducing cracks due to leakage and improving workability by reducing construction joints. However, to apply the proposed method of this study, it is judged that sufficient estimations are necessary as there are differences in ground conditions, temporary facilities, and reinforcement methods for each site.