• Journal of Wetlands Research
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• v.23 no.1
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• pp.85-93
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• 2021

Sewage separation which often involves installing a new pipe to separate wastewater flow from stormwater runoff flow can be costly and depends highly on its feasibility in a site. To be able to develop a potentially more economical alternative that can also lessen major road traffic disturbance during this process, a different approach where a smaller sewage separator pipe is installed inside an existing combined sewer pipe was investigated. A small-scale of a box sewer and the proposed sewage separator pipe was constructed in the laboratory to observe and compare the deposition of solids and other solid-associated major pollutants at different flow rates. In addition, three-dimensional flow simulations considering five different scenarios were conducted using Ansys Fluent to observe the effect of the proposed sewage separator pipe to the hydraulic flow if installed inside the combined sewer pipe. Results revealed that the deposition of TSS, TCOD, TN, and TP were reduced by at least 60% when the wastewater was conveyed by the sewage separator pipe instead of the combined sewer pipe. Moreover, the flow simulations conducted showed that there was little to no major disturbance in hydraulic flow and velocity distribution when the sewage separator was installed inside a straight pipe and even at pipe transitions such as intersections, turns, and drop in elevation. Considering the pipe dimensions and the results of the study, the proposed approach can be promising in terms of reduction in pollutant deposition without a major effect on the hydraulic flow. Further investigation and cost-analysis should be done in the future to support these preliminary findings and help alleviate the problems caused by combined sewer overflows by introducing an alternative approach.

• Journal of Environmental Impact Assessment
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• v.30 no.2
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• pp.89-104
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• 2021

This study investigated the public opinion on the use and conservation management of national park, to manage the growing demand of national park visit and to support the policy direction of national park. So far, various surveys and big data analysis on the use and perception of national park have been conducted, but there have been limitations such as lack of survey questions on issues in park management and use. In addition, the object of the previous studies were limited to the national park visitors; therefore, this study expanded the object of survey from national park visitors to ordinary citizens. Unlike previous studies conducted only on national park visitors, ordinary citizens relatively prefered bottom areas rather than high-altitude ones. A policy to limit the visit to high-ridge area of mountain is being currently driven; however, the survey results of ordinary citizens suggested to maintain current policies or to increase visitor reservations system within narrow limits. On the other hand, the proportion of citizens who have used the visitor-reservation system was very small. We discuss the difference between national park visitors and ordinary citizens and the policy conditions according to changes in park management principles and public attitudes toward national parks.

• Journal of Korean society of Dental Hygiene
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• v.21 no.4
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• pp.467-479
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• 2021

Objectives: The purpose of this study was to investigate the awareness of the performance and necessity of oral health promotion activities and seek ways to revitalize the professional role of dental hygienists in oral healthcare for the efficient oral care of the elderly. Methods: Eighty-five dental hygienists in charge of oral health promotion projects at public health centers and 38 dental hygienists in network dental clinical trials were investigated for their learning experience, performance experience, feasibility, and necessity of dental hygienists for general and oral health service items for the elderly. The collected data were analyzed using frequency analysis, chi-square test, and Mann-Whitney U test. Results: The degree of performance possibility according to the learning experience and performance experience of the dental hygienist for the whole body and oral health promotion activity items for the elderly showed that the degree of performance possibility was higher among those with experience compared to the non-experienced person, and it was statistically significantly higher (p<0.05). Conclusions: The dental hygienist's professional oral health service is a necessary system to improve practical knowledge and skills and to provide a wide range of professional oral health services for the elderly.

• Explosives and Blasting
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• v.39 no.4
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• pp.22-33
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• 2021

Recently, the frequent occurrence of ground subsidence in urban areas has caused increasing anxiety in residents and incurred significant social costs. Among the causes of ground subsidence, the rupture of old water and sewer pipes not only halts the operation of the buried pipes, but also leads to ground and water pollution problems. However, because most pipes are buried after construction and cannot be seen with the naked eye, the importance of maintenance has underestimated compared to other structures. In recent years, integrated physical exploration has been applied to the maintenance of underground pipes and structures. Currently, to investigate the internal conditions and vulnerable portions of the ground, consolidated physical surveys are executed. Consolidated physical surveys are analysis techniques that obtain various material data and add existing data using multiple physical surveys. Generally, in geotechnical engineering, consolidated physical surveys including electrical and surface wave surveys are adopted. However, it is difficult to investigate time-based changes in under ground using these surveys. In contrast, surveys using cosmic-ray muons have been used to scan the inner parts of nuclear reactors with penetration technology. Surveys using muons enable real-time observation without the influence of vibration or electricity. Such surveys have great potential for available technology because of their ability to investigate density distributions without requiring as much labor. In this paper, survey technologies using cosmic ray muons are introduced, and the possibilities of applying such technologies as new physical survey technologies for underground structures are suggested.

• Journal of Wetlands Research
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• v.24 no.1
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• pp.59-67
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• 2022

The interest in LID facilities is increasing worldwide for recovery of natural water cycle system to destroy by urbanization. However, problems are raised when installation of LID because comprehensive analysis about design capacity adequacy of LID facilities was not conducted completely. In this research, removal efficiency and design volume adequacy of LID facilities were analyzed based on rainfall monitoring data in four LID facilities(Vegetated Swale, Vegetative Filter Strip, Bio-Retention and Permeable Pavement). As a result, group of LID facility designed on WQV was shown higher flow(37%) and pollutants(TSS, BOD, TN and TP) removal efficiencies(20 ~ 37%) than group of LID facility designed on WQF. SA/CA graph was drawn for evaluation of design volume adequacy based on rainfall monitoring data. In this SA/CA graph, coefficient of determination show over 0.5 in all parameter, especially, Flow and TP were show over 0.95. And, 'SA/CA & L/CA' graph considering difference of structure mechanism in LID facility suggested in this research was confirmed that improved coefficient of determination in flow, TSS and TP than SA/CA graph. According to this research results, feasibility of applying 'SA/CA & L/CA' graph for evaluation of design volume adequacy in LID facility, and it is necessary to follow up research for generalization and normalization.

• Journal of the Korean Geosynthetics Society
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• v.21 no.1
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• pp.11-21
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• 2022

In this study, the individual vacuum seepage consolidation method, a new soft ground improvement method, was developed to supplement the conventional suction drain method (individual vacuum preloading method) and the geotechnical behavior was predicted through numerical analysis. If the individual vacuum seepage consolidation method applied, the effect of accelerating settlement and increasing the amount of settlement was high when the aquifer was located in the middle or at the bottom of the layer to the target improvement layer. It was found that the pumping amount in the aquifer does not affect the settlement behavior when it exceeds a certain level. Even vacuum pumping wells were installed in various locations, such as inside or outside of the embankment, the difference in settlement and horizontal displacement was insignificant. In addition, it was predicted that the settlement rate was the fastest and the horizontal displacement (inward) was large when both methods were carried out at the same time. Since this method can reach the target settlement amount very quickly, it was confirmed that it is possible to increase the spacing of vertical drain, thereby securing economic feasibility.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.287-301
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• 2022

This study aims to propose a crane-tip control method to intuitively control the end-effector vertically or horizontally for improving the crane work efficiency and to confirm the control performance. To verify the control performance based on experimental variables, a laboratory-scale crane was manufactured using an electric cylinder. Through a forward and reverse kinematics analysis, the crane was configured to output the position coordinates of the current crane-tip and the joint angle at each target point. Furthermore, a method of generating waypoints was used, and a dead band using lateral boundary offset (LBO) was set. Appropriate parameters were selected using bang-bang control, which confirmed that the number of waypoints and LBO radius were associated with positioning error, and the cylinder speed was related to the lead time. With increased number of waypoints and decreased LBO radius, the positioning error and the lead time also decreased as the cylinder speed decreased. Using the proportional control, when the cylinder velocity was changed at every control cycle, the lead time was greatly reduced; however, the actual control pattern was controlled by repeating over and undershoot in a large range. Therefore, proportional control was performed by additionally applying velocity gain that can relatively change the speed of each cylinder. Since the control performed with in a range of 10 mm, it was verified th at th e crane-tip control can be ach ieved with only th e proportional control to which the velocity gain was applied in a control cycle of 20 ms.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.327-334
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• 2022

In this study, the purpose of this study was to conduct a basic study on the effectiveness and feasibility of the regulation of the Nuclear Safety Act for the department of radiology by examining the questionnaire on the satisfaction of on-campus practice while attending the department of radiology and the current status of radiation workers and radiation related workers. As for the satisfaction of the workers who were designated as frequent visitors while attending the department of radiology and did not handle and operate the radiation generator during on-campus training, 34.62% of the workers answered 'not satisfied'. On the other hand, 50% of workers who were designated as radiation workers while attending school or who were enrolled in school before the regulation of the nuclear safety act and handled and operated radiation generators were 'satisfied' at 50%. In addition, the annual exposure dose of radiation workers in educational institutions was found to be less than 0.05 mSv. If you look at the trends of radiation workers and radiation workers, it can be seen that students who graduate from the Department of Radiology find the most employment in the field dealing with diagnostic radiation generators registered as radiation workers among medical institutions. Therefore, by easing the regulations of the current Nuclear Safety Act or by amending the medical act and the rules on the safety management of diagnostic radiation generating devices, etc. It is presumed that something is necessary.

• Journal of Environmental Impact Assessment
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• v.31 no.3
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• pp.129-140
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• 2022

Environmental impact assessment on development projects is a process in which various stakeholders derive consultations by reflecting project characteristics and regional environmental status, and implementation of consultations is a prerequisite for securing sustainability of the local environment. The business plan can be changed to respond to changes in social and environmental conditions. And the business plan for which the environmental impact assessment consultation has been completed, it can be changed as a systematically prepared procedure (called Consultations on Amendment). As a result of investigating and analyzing the current status and major changes in the development project, Consultations on Amendment in industrial complexes were the most common, and the environmental impact is increasing accordingly. As the results of the analysis of operational status and the case studies, the main causes of Consultations on Amendment in industrial complex can be summarized into three categories: (1) formal demand forecasting for tenant industries, (2) excessive omission and simplification of administrative procedures under the Special Act, and (3) the use of an expedient change consultation system to facilitate environmental impact assessment consultation and shorten the period. This study proposes the following three measures to prevent the deterioration of the environmental impact assessment function due to frequent consultations on industrial complex changes; (1) Ensuring residents' participation procedures for Consultations on Amendment that changes important matters, (2) Reasonable revision of the "Simplification of Industrial Complex Procedures Act" to enhance the feasibility of industrial complex development plans and locations, (3) Development of evaluation criteria and methods for verification of real demand for objective demand management for industrial complexes, and (4) Preparation of a review guideline for Consultations on Amendment.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1069-1080
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• 2022

The tropospheric ozone is a pollutant that causes a great deal of damage to humans and ecosystems worldwide. In the event that ozone moves downwind from its source, a localized problem becomes a regional and global problem. To enhance ozone monitoring efficiency, geostationary satellites with continuous diurnal observations have been developed. The objective of this study is to derive the Tropospheric Ozone Movement Vector (TOMV) by employing continuous observations of tropospheric ozone from geostationary satellites for the first time in the world. In the absence of Geostationary Environmental Monitoring Satellite (GEMS) tropospheric ozone observation data, the GEOS-Chem model calculated values were used as synthetic data. Comparing TOMV with GEOS-Chem, the TOMV algorithm overestimated wind speed, but it correctly calculated wind direction represented by pollution movement. The ozone influx can also be calculated using the calculated ozone movement speed and direction multiplied by the observed ozone concentration. As an alternative to a backward trajectory method, this approach will provide better forecasting and analysis by monitoring tropospheric ozone inflow characteristics on a continuous basis. However, if the boundary of the ozone distribution is unclear, motion detection may not be accurate. In spite of this, the TOMV method may prove useful for monitoring and forecasting pollution based on geostationary environmental satellites in the future.