• Journal of Korean Society of Environmental Engineers
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• v.31 no.1
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• pp.51-57
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• 2009

Biofouling in seawater reverse osmosis (SWRO) desalination process causes many problems such as flux decline, biodegradation of membrane, increased cleaning time, and increased energy consumption and operational cost. Therefore biofouling is considered as the most critical problem in system operation. To control biofouling in early stage, detection of the most problematic bacteria causing biofouling is required. In this study, six model bacteria were chosen; Bacillus sp., Flavobacterium sp., Mycobacterium sp., Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhodobacter sp. based on report in the literature and phylogenetic analysis of seawater intake and fouled RO membrane. The adhesion to RO membrane, the high pressure resistance, and the hydrophobicity of the six model bacteria were examined to find out their fouling potential. Rhodobacter sp. and Mycobacterium sp. were found to attach very well to RO membrane surface compared to others used in this study. The test of hydrophobicity revealed that the bacteria which have high hydrophobicity or similar contact angle with RO membrane ($63^{\circ}$ of contact angle) easily attached to RO membrane surface. P. aeruginosa which is highly hydrophilic ($23.07^{\circ}$ of contact angle) showed the least adhesion characteristic among six model bacteria. After applying a pressure of 800 psi to the sample, Rhodobacter sp. was found to show the highest reduction rate; with 59-73% of the cells removed from the membrane under pressure. P. fluorescens on the other hand analyzed as the most pressure resistant bacteria among six model bacteria. The difference between reduction rates using direct counting and plate counting indicates that the viability of each model bacteria was affected significantly from the high pressure. Most cells subjected to high pressure were unable to form colonies even thought they maintained their structural integrity.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.143-152
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• 2012

This study was performed to reduce the operating cost of a greenhouse by securing electric energy required for greenhouse operation. Therefore, it experimentally reviewed the performance analysis of photovoltaic system in terms of maximum amount of generated electric power based on the amount of horizontal solar radiation during daytime. That is to say, the maximum solar radiation at 300, 400, 500, 600, 700, 800 and 900 W. $m^{-2}$, respectively. The amount of momentary electric power of the photovoltaic system at any was about 970 W and we found that the momentary efficiency of the photovoltaic system that was used for this experiment was 97%. In the case of this system, we found that electric power will be generated when amount of horizontal solar radiation is more than 200 W. $m^{-2}$, at minimum. If the amount of horizontal solar radiation is increased, the maximum power generation is also increased. At that time, the maximum efficiencies were 30, 78, 86 and 90%, respectively. However, when the amount of insolation was about 800 W. $m^{-2}$, the maximum power generation tended to be lower than 700 W. $m^{-2}$. The efficiency which caused the maximum electric power was decreased to less than 97% of the momentary generated electric power. When the total amounts of horizontal solar radiation per day were 3.24, 8.10, 10, 90, 12.70, 14.33, 19.53 and $21.48MJ{\cdot}m^{-2}$ respectively, the total amounts of power energy were 0.03, 0.40, 3.60, 4.37, 4.71, 4.70 and 4.91 kWh. And it represented that the total amounts of power energy were either decreased or increased a bit on the border between some solar radiations. The temperature at the back of the array tended to be higher than the temperature at the front but it demonstrated an increased when the amount of solar radiation increased. In the case of this system, the performance of the module in terms of degradation has not been shown yet.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1339-1348
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• 2021

In accordance with the River Law, the basic river maintenance plan is established every 5-10 years with a considerable national budget for domestic rivers, and various river surveys such as the river section required for HEC-RAS simulation for flood level calculation are being conducted. However, river survey data are provided only in the form of a pdf report to the River Management Geographic Information System (RIMGIS), and the original data are distributedly owned by designers who performed the river maintenance plan in CAD format. It is a situation that the usability for other purposes is considerably lowered. In addition, when using surveyed CAD-type cross-sectional data for HEC-RAS, tools such as 'Dream' are used, but the reality is that time and cost are almost as close as manual work. In this study, RAUT (River Information Auto Upload Tool), a tool that can solve these problems, was developed. First, the RAUT tool attempted to automate the complicated steps of manually inputting CAD survey data and simulating the input data of the HEC-RAS one-dimensional model used in establishing the basic river plan in practice. Second, it is possible to directly read CAD survey data, which is river spatial information, and automatically upload it to the river spatial information DB based on the standard data model (ArcRiver), enabling the management of river survey data in the river maintenance plan at the national level. In other words, if RIMGIS uses a tool such as RAUT, it will be able to systematically manage national river survey data such as river section. The developed RAUT reads the river spatial information CAD data of the river maintenance master plan targeting the Jeju-do agar basin, builds it into a mySQL-based spatial DB, and automatically generates topographic data for HEC-RAS one-dimensional simulation from the built DB. A pilot process was implemented.

• The Korean Journal of Archival Studies
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• no.11
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• pp.181-214
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• 2005

Metropolitan rapid transit system plays an essential role in the public transportation system of any large city, and its managing agency is usually charged with the responsibility of storing and managing the design drawings of the system. The drawings are important and historically valuable documents that must be kept permanently because they contain comprehensive data that is used to manage and maintain the system. However, no study has been performed in Korea on how well agencies are preserving and managing these records. Seoul Metropolitan Rapid Transit Corporation(SMRT) is the managing agency established by the city of Seoul to operate subway lines 5, 6, 7, and 8 more efficiently to serve its citizens. By the Act on Records Management in Public Institutions(ARMPI), SMRT should establish a records center to manage its records. Furthermore, all drawings produced by SMRT and other third party entities should be in compliance with the Act. However, SMRT, as a form of local public corporation, can establish a records center by its own way. Accordingly, the National Archives & Records Service(NARS) has very little control over SMRT. Therefore, the purpose of this study is to research and analyze the present state of storage and management of the drawings of metropolitan rapid transit in SMRT and is to find a desirable method of preservation and management for drawings of metropolitan rapid transit. In the process of the study, it was found that a records center is being considered to manage only general official documents and not to manage the drawings as required by ARMPI. SMRT does not have a records center, and the environment of management on the drawings is very poor. Although there is a plan to develop a new management system for the drawings, it will be non-compliant of ARMPI. What's happening at SMRT does not reflect the state of all other cities' metropolitan rapid transit records management systems, but the state of creation of records center of local public corporation is the almost same state as SMRT. There should be continuous education and many studies conducted in order to manage the drawings of metropolitan rapid transit efficiently by records management system. This study proposes a records center based on both professional records centers and union records centers. Although metropolitan rapid transit is constructed and managed by each local public corporation, the overall characteristics and processes of metropolitan rapid transit projects are similar in nature. In consideration of huge quantity, complexity and specialty of drawings produced and used during construction and operation of metropolitan rapid transit, and overlap of each local public corporation's effort and cost of the storage and management of the drawings, they need to be managed in a professional and united way. As an example of professional records center, there is the National Personnel Records Center(NPRC) in St. Louis, Missouri. NPRC is one of the National Archives and Records Administration's largest operations and a central repository of personnel-related records on former and present federal employees and the military. It provides extensive information to government agencies, military veterans, former federal employees, family members, as well as researchers and historians. As an example of union records center, there is the Chinese Union Dangansil. It was established by several institutions and organizations, so united management of records can be performed and human efforts and facilities can be saved. We should establish a professional and united records center which manages drawings of metropolitan rapid transit and provides service to researchers and the public as well as members of the related institutions. This study can be an impetus to improve interest on management of not only drawings of metropolitan rapid transit but also drawings of various public facilities.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.737-743
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• 2018

Patient exposure dose exposure test, which is one of the items of accuracy control of Computed Tomography, conducts measurements every year based on the installation and operation of special medical equipment under Article 38 of the Medical Law, And keep records. The CT-Dose phantom used for dosimetry can accurately measure doses, but has the disadvantage of high price. Therefore, through this research, the existing CT - Dose phantom was similarly manufactured with a 3D printer and compared with the existing phantom to examine the usefulness. In order to produce the same phantom as the conventional CT-Dose phantom, a 3D printer of the FFF method is used by using a PLA filament, and in order to calculate the CTDIw value, Ion chambers were inserted into the central part and the central part, and measurements were made ten times each. Measurement results The CT-Dose phantom was measured at $30.44{\pm}0.31mGy$ in the periphery, $29.55{\pm}0.34mGy$ CTDIw value was measured at $30.14{\pm}0.30mGy$ in the center, and the phantom fabricated using the 3D printer was measured at the periphery $30.59{\pm}0.18mGy$, the central part was $29.01{\pm}0.04mGy$, and the CTDIw value was measured at $30.06{\pm}0.13mGy$. Analysis using the Mann - Whiteney U-test of the SPSS statistical program showed that there was a statistically significant difference in the result values in the central part, but statistically significant differences were observed between the peripheral part and CTDIw results I did not show. In conclusion, even in the CT-Dose phantom made with a 3D printer, we showed dose measurement performance like existing CT-Dose phantom and confirmed the possibility of low-cost phantom production using 3D printer through this research did it.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.424-431
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• 2018

Stormwater runoff containing considerable amounts of pollutants such as particulates, organics, nutrients, and heavy metals contaminate natural bodies of water. At present, best management practices (BMP) intended to reduce the volume and treat pollutants from stormwater runoff were devised to serve as cost-effective measures of stormwater management. However, improper design and lack of proper maintenance can lead to degradation of the facility, making it unable to perform its intended function. This study evaluated an infiltration trench (IT) that went through a series of maintenance operations. 41 monitored rainfall events from 2009 to 2016 were used to evaluate the pollutant removal capabilities of the IT. Assessment of the water quality and hydrological data revealed that the inflow volume was the most relative factor affecting the unit pollutant loads (UPL) entering the facility. Seasonal variations also affected the pollutant removal capabilities of the IT. During the summer season, the increased rainfall depths and runoff volumes diminished the pollutant removal efficiency (RE) of the facility due to increased volumes that washed off larger pollutant loads and caused the IT to overflow. Moreover, the system also exhibited reduced pollutant RE for the winter season due to frozen media layers and chemical-related mechanisms impacted by the low winter temperature. Maintenance operations also posed considerable effects of the performance of the IT. During the first two years of operation, the IT exhibited a decrease in pollutant RE due to aging and lack of proper maintenance. However, some events also showed reduced pollutant RE succeeding the maintenance as a result of disturbed sediments that were not removed from the geotextile. Ultimately, the presented effects of maintenance operations in relation to the pollutant RE of the system may lead to the optimization of maintenance schedules and procedures for BMP of same structure.

• Journal of Bio-Environment Control
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• v.28 no.1
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• pp.46-54
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• 2019

Experiments of local cooling and heating on crown and root zone of forcing cultivation of strawberry 'Seolhyang' using heat pump and root pruning before planting were conducted. During the daytime, the crown surface temperature of the crown local cooling treatment was maintained at $18{\sim}22^{\circ}C$. This is suitable for flower differentiation, while those of control and root zone local cooling treatment were above $30^{\circ}C$. Budding rate of first flower clusters and initial yields were in the order of crown local cooling, root zone local cooling and control in root pruning plantlet and non pruning plantlet, except for purchase plantlet. Those of root pruning plantlet were higher than those of non pruning plantlet. These trends were evident in the yield of the first flower cluster until February 14, 2018, and the effect of local cooling and root pruning decreased from March 9, 2018. The budding rates of the second flower cluster according to the local cooling and root pruning treatments were not noticeable compared to first flower cluster but showed the same tendency as that of first flower cluster. In the heating experiment, root zone local heating(root zone $20^{\circ}C$+inside greenhouse $5^{\circ}C$) and crown local heating(crown $20^{\circ}C$+inside greenhouse $5^{\circ}C$) saved 59% and 65% of heating fuel, respectively, compared to control(inside greenhouse $9^{\circ}C$). Considering the electric power consumption according to the heat pump operation, the heating costs were reduced by 55% and 61%, respectively.

• Journal of Arbitration Studies
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• v.29 no.2
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• pp.239-282
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• 2019

The importance of ADR(Alternative Dispute Resolution), which has the advantage of expertise, speed and neutrality due to the increase of arbitration cases due to domestic and foreign construction disputes, has emerged. Therefore, in order for the nation's arbitration system and the arbitration Organization to jump into the ranks of advanced international mediators, it is necessary to research the characteristics and advantages of these arbitration Organization through a study of prior domestic and foreign research and operation of international arbitration Organization. As a problem, First, education for the efficient promotion of arbitrators (compulsory education, maintenance education, specialized education, seminars, etc.). second, The effectiveness of arbitration in resolving construction disputes (hearing methods, composition of the tribunal, and speed). third, The issue of flexibility and diversity of arbitration solutions (the real problem of methodologies such as mediation and arbitration) needs to be drawn on the Arbitration laws and practical problems, such as laws, rules and guidelines. Therefore, Identify the problems presented in the preceding literature and diagnosis of the defects and problems of the KCAB by drawing features and benefits from the arbitration system operated by the international arbitration Institution. As an improvement, the results of an empirical analysis are derived for "arbitrator" simultaneously through a recognition survey. As a method of improvement, First, as an optimal combination of arbitration hearing and judgment in the settlement of construction disputes,(to improve speed). (1) A plan to improve the composition of the audit department according to the complexity, specificity, and magnification of the arbitration cases - (1)Methods to cope with the increased role of the non-lawyer(Specialist, technical expert). (2)Securing technical mediators for each specialized expert according to the large and special corporation arbitration cases. (2) Improving the method of writing by area of the arbitration guidelines, second, Introduction of the intensive hearing system for psychological efficiency and the institutional improvement plan (1) Problems of optimizing the arbitration decision hearing procedure and resolution of arbitration, and (2) Problems of the management of technical arbitrators of arbitration tribunals. (1)A plan to expand hearing work of technical arbitrator(Review on the introduction of the Assistant System as a member of the arbitration tribunals). (2)Improved use of alternative appraisers by tribunals(cost analysis and utilization of the specialized institution for calculating construction costs), Direct management of technical arbitrators : A Study on the Improvement of the Assessment Reliability of the Appraisal and the Appraisal Period. third, Improvement of expert committee system and new method, (1) Creating a non-executive technical committee : Special technology affairs, etc.(Major, supports pre-qualification of special events and coordinating work between parties). (2) Expanding the standing committee.(Added expert technicians : important, special, large affairs / pre-consultations, pre-coordination and mediation-arbitration). This has been shown to be an improvement. In addition, institutional differentiation to enhance the flexibility and diversity of arbitration. In addition, as an institutional differentiation to enhance the flexibility and diversity of arbitration, First, The options for "Med-Arb", "Arb-Med" and "Arb-Med-Arb" are selected. second, By revising the Agreement Act [Article 28, 2 (Agreement on Dispute Resolution)], which is to be amended by the National Parties, the revision of the arbitration settlement clause under the Act, to expand the method to resolve arbitration. third, 2017.6.28. Measures to strengthen the status role and activities of expert technical arbitrators under enforcement, such as the Act on Promotion of Interestments Industry and the Information of Enforcement Decree. Fourth, a measure to increase the role of expert technical Arbitrators by enacting laws on the promotion of the arbitration industry is needed. Especially, the establishment of the Act on Promotion of Intermediation Industry should be established as an international arbitration agency for the arbitration system. Therefore, it proposes a study of improvement and differentiation measures in the details and a policy, legal and institutional improvement and legislation.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.140-146
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• 2019

In order to manage non-point sources, the paradigm of the system should be changed so that the management of non-point sources will be systematized from the beginning of the use and development of the land. It is necessary to change the method of national subsidy support and poeration plan for the non-point source management area. In order to increase the effectiveness of the non-point source reduction project, it is necessary to provide a minimum support ratio and to provide additional support according to the performance of the local government. A new system should be established to evaluate the performance of non-point source reduction projects and to monitor the operational effectiveness. It is necessary to establish the related rules that can lead the local government to take responsible administration so that the local governments faithfully carry out the non-point source reduction project and achieve the planned achievement and become the sustainable maintenance. Alternative solutions are needed, such as problems with the use of $100{\mu}m$ filter in automatic sampling and analysis, timely acquisition of water sampling and analysis during rainfall, and effective management of non-point sources network operation management. As an alternative, it is necessary to consider improving the performance of sampling and analysis equipment, and operate the base station. In addition, countermeasures are needed if the amount of pollutant reduction according to the non-point source reduction facility promoted by the national subsidy is required to be used as the development load of the TMDLs. As an alternative, it is possible to consider supporting incentive type of part of the maintenance cost of the non-point source reduction facility depending on the amount of pollutants reduction.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.202-217
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• 2022

Purpose: The recent increased use of Personal Mobility (PM) has been accompanied by a rise in the annual number of accidents. Accordingly, the safety requirements for PM use are being strengthened, but the laws/systems, infrastructure, and management systems remain insufficient for fostering a safe environment. Therefore, this study comprehensively searches the main problems and improvement methods through a review of previous studies that are related to PM. Then the priorities according to the importance of the improvement methods are presented through the Delphi survey. Method: The research method is mainly composed of a literature study and an expert survey (Delphi survey). Prior research and improvement cases (local governments, government departments, companies, etc.) are reviewed to derive problems and improvements, and a problem/improvement classification table is created based on keywords. Based on the classification contents, an expert survey is conducted to derive a priority improvement plan. Result: The PM-related problems were in 'non-compliance with traffic laws, lack of knowledge, inexperienced operation, and lack of safety awareness' in relation to human factors, and 'device characteristics, road-drivable space, road facilities, parking facilities' in relation to physical factors. 'Management/supervision, product management, user management, education/training' as administrative factors and legal factors are divided into 'absence/sufficiency of law, confusion/duplication, reduced effectiveness'. Improvement tasks related to this include 'PM education/public relations, parking/return, road improvement, PM registration/management, insurance, safety standards, traffic standards, PM device safety, PM supplementary facilities, enforcement/management, dedicated organization, service providers, management system, and related laws/institutional improvement', and 42 detailed tasks are derived for these 14 core tasks. The results for the importance evaluation of detailed tasks show that the tasks with a high overall average for the evaluation items of cost, time, effect, urgency, and feasibility were 'strengthening crackdown/instruction activities, education publicity/campaign, truancy PM management, and clarification of traffic rules'. Conclusion: The PM market is experiencing gradual growth based on shared services and a safe environment for PM use must be ensured along with industrial revitalization. In this respect, this study seeks out the major problems and improvement plans related to PM from a comprehensive point of view and prioritizes the necessary improvement measures. Therefore, it can serve as a basis of data for future policy establishment. In the future, in-depth data supplementation will be required for each key improvement area for practical policy application.