• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1073-1090
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• 2018

Since the domestic utility tunnels were built mainly in the development project of the new city, they are all in the form of cut-and-cover box tunnel. But, in the case of overseas construction of utility tunnels for existing urban areas, the bored tunnel types are mainly adopted. It is reasonable to install bored tunnels in a downtown area because it is difficult to block the roads or install bypass roads due to heavy traffic and civil complaints. In order to activate the utility tunnels in bored type, it is necessary to secure optimized cross-sectional design technology considering the optimal supplying capacity and mutual influencing factors (Thermal Interference, electrolytic corrosion, efficiency of the maintenance, etc.) of utilities (power cables, telecommunication cables, water pipes, etc.). The optimal cross-section design method for bored utility tunnels is ultimately to derive the optimal arrangement technique for the utilities. In order to develop the design methods, firstly, the cases of tunnel cross-section (Shield TBM, Conventional Tunneling) in overseas shall be investigated to analyze the characteristics of the installation of utilities in the section and installation of auxiliary facilities, It is necessary to sort out and analyze the criteria related to the inner cross-section design (arrangement) presented in the standards and guidelines.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.115-168
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• 2018

An amendment to Japanese Civil Aeronautics Act came into effect December 10, 2015. The Act prohibits flying drones over residential areas or areas surrounding an airport without permission from the Minister of Land, Infrastructure and Transportation. Flying drones during night time and during an event is also prohibited. The term "UAV" or "UA" means any aeroplane, rotorcraft, glider or airship which cannot accommodate any person on board and can be remotely or automatically piloted (Excluding those lighter than a certain weight (200 grams). Any person who intends to operate a UAV is required to follow the operational conditions listed below, unless approved by the Minister of Land, Infrastructure, Transport and Tourism; (i) Operation of UAVs in the daytime, (ii) Operation of UAVs within Visual Line of Sight (VLOS), (iii) Maintenance of a certain operating distance between UAVs and persons or properties on the ground/water surface, (iv) Do not operate UAVs over event sites where many people gather, (v) Do not transport hazardous materials such as explosives by UAV, (vi) Do not drop any objects from UAVs. Requirements stated in "Airspace in which Flights are Prohibited" and "Operational Limitations" are not applied to flights for search and rescue operations by public organizations in case of accidents and disasters. This paper analyzes some issues as to regulations of UAVs in Korean Aviation Safety Act by comparing the regulations of UAVs in Japanese Civil Aeronautics Act. This paper, also, offers some implications and suggestions for regulations of UAVs under Korean Aviation Safety Act.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.324-330
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• 2018

In accordance with the amendment of the Industrial Safety and Health Act of 2007, Korea completely prohibited the import, distribution and manufacture of asbestos like Europe and Japan. Accordingly, the current problem of asbestos is the safe maintenance and disposal of asbestos construction material, the disposal of asbestos, and the final disposal of asbestos building materials. In the past, Korea used 100,000 tons of asbestos every year, and the building materials using it exceeded 1 million tons per year. These asbestos building materials continued to be used until 2006, and the Ministry predicted that these materials would continue to be maintained until 2044. When the permeable hardening agent is applied to the asbestos building material installed in the pre-pretreatment step for the harmless treatment of the asbestos waste and the dismantling is carried out, the scattering of the asbestos is suppressed in the disassembling step, detoxification treatment conditions can be improved. Therefore, permeable hardeners should be stably penetrated into asbestos building materials. In this study, it is suggested that pre - pretreatment methods for the harmlessization of waste asbestos building materials with medium density level can be presented. In order to efficiently perform pre - treatment for chemical harmlessness in the future, the mixing ratio of permeable hardener and middle water Optimization is the most important factor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.496-499
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• 2014

Xe Gas is moved to Target from GPM. It is Used to feasible nuclear reaction from proton of 30MeV Cyclotron being investigated by the Xe-124 Gas target System. This system is divided into four parts. Hardware was constructed by solidworks and Helium Supply is to cool the Havor Foil. Water has the job of cooling down the temperature when Xe Gas is being investigated in the target. Temperature and pressure gauges are attached to be checked easily. GPM(Gas Process Manifold) has the part that prepares to transport Xe Gas. There are Storage Vessel that stores Xe Gas, the cold trap that filters humidity and impurity and lastly storage vessel that temporarily stores Xe Gas. HCS(Helium Circulation System) using the Helium to cleaning and cooling. these parts are used to SIEMENS PLC and Pcvue Program. Because It is more comfortable and easy maintenance.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.609-616
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• 2019

When the fouling of a vessel occurs, its resistance at sea increases and there is a corresponding increase in fuel consumption. The maintenance cost of the vessel also increases because it is time-consuming to remove the fouling. To solve this problem and minimize environmental contamination of sea-water, there have been recent developments in anti-fouling paints as self-polishing copolymers that not include toxic elements such as tin. When these conventional techniques are applied to vessels, polishing is promoted during the operation whereby friction or vibration with seawater occurs. This leads to enhanced anti-fouling performance. However, when fouling is intensified such as during an anchorage, there is no flow of seawater and polishing is suppressed. This leads to a deterioration of the performance of anti-fouling. To solve these problems, we developed a system that induces vibration in a vessel during anchorage. As such, the deterioration of polishing due to insuf icient flow of seawater is inhibited. The reliability of the ultrasonic antifouling system was evaluated by calculating its repeatability. The removal efficiency of fouling of the proposed system was qualitatively evaluated using test specimens. The test revealed that the value of the coefficient of variation for the reproducibility of the frequency and amplitude was 0.2 % and 4.0 % on average. The degree of fouling of the specimens was the highest at 73.3 g in the No.5 sepcimen. Moreover, efficiency of fouling removal was 93.2 % on average compared to the specimens without the proposed system.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.734-746
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• 2020

Purpose: Increase in the size and number of underpasses rises occurrence of disasters such as fire and flooding inundation in underpasses. In the occurrence of disasters, the underpasses are more vulnerable to expose of crucial disasters than the general roads due to they are built underground. Therefore, The purpose of this paper is to derive system improvement items to prevent and control disasters in underpasses. Method: A hierarchical model of disaster impact factors and alternatives was developed based on prior researches and expert advices on disaster analyses and impact factors in the underpasses. The developed model was employed for surveys of pairwise comparison, and rankings of improvement were determined by applying the AHP method. Result: With a consistency of the surveys, results of relative weights of evaluation criteria(traffic accidents, fire, flooding inundation) and alternatives(law, system/planning, maintenance/human factor/environment) shows that improvement of laws and system related to the fire disaster is a top priority to prevent and control disaster of the underpasses. Conclusion: From experts' point of view, strengthening laws and systems related to disater prevention facilities such as water spray facilities, external(ground) exit in relation to fire in underpasses showed that it is an alternative to prevent disasters and minimize damage to underpasses.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.496-505
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• 2020

In the previous research, the effectiveness of resonator was confirmed through the numerical analysis on two cases with the use of existing resonator at the Mukho and Imwon ports located in the eastern coast of South Korea by discussing the reduction rates of 1983 Central East Sea tsunami, and 1993 Hokkaido Southwest off tsunami, respectively. In this study, the reduction rates of tsunami height with three different resonators, Type I, II-1, and II-2, at the Samcheok port were examined respectively through the numerical analysis using COMCOT model under the same condition as the previous study. It was discussed the spatial distribution of maximum height of tsunami, change of water level, and effectiveness of resonator with the presence of new types of resonator, and change of their sizes. As a result, the effectiveness of resonator was verified through the application of new types of resonator reducing about maximum 40% of tsunami height. In order to design the optimal resonator for the variety of site condition, it is necessary to research about the various cases applying different shape, arrangement, and size of resonator as further study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.409-414
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• 2021

Tightness performance that blocks compartments is important for surface ships to achieve superior mission performance and survivability in combat environments. To meet the above requirements, airtightness of the structural elements and the appropriate strength to specific areas are checked during a test run after ship construction. In particular, air tests of compartments adjacent to the water surface are performed. In an air test, air is injected into the compartment up to the test pressure of the test memo. The pressure drop value is checked after 10 minutes to determine if the requirements of the corresponding area are satisfied. In summer, however, when the influence of the outside temperature is large, a phenomenon in which the internal pressure increases during the air test was identified. This phenomenon reduces the reliability of the test result. Therefore, a system was designed to compensate for temperature changes in the compartments through this study. The developed system calculates the amount of pressure change caused by a temperature change in the compartment and outputs a correction value. The pressure change was calculated using the ideal gas equation, reflecting the maintenance, increase, and decrease in temperature during the test process. A comparison of the calculated pressure correction value with the database of NIST REFPROP revealed a difference of 0.126% to a maximum of 0.253%.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.561-568
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• 2020

Wave measurements using X-band radar have many advantages compared to other wave gauges including wave-rider buoy, P-u-v gauge and Acoustic Doppler Current Profiler (ADCP), etc.. For example, radar system has no risk of loss/damage in bad weather conditions, low maintenance cost, and provides spatial distribution of waves from deep to shallow water. This paper presents new methods for estimating significant wave heights of X-band marine radar images using Artificial Neural Network (ANN). We compared the time series of estimated significant wave heights (Hs) using various estimation methods, such as signal-to-noise ratio (${\sqrt{SNR}}$), both and ${\sqrt{SNR}}$ the peak period (TP), and ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k). The estimated significant wave heights of the X-band images were compared with wave measurement using ADCP(AWC: Acoustic Wave and Current Profiler) at Hujeong Beach, Uljin, Korea. Estimation of Hs using ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k) yields best result.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.44-53
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• 2021

Urban stormwater runoff contains heavy metals that accumulate in on-site treatment systems, thus resulting to facility deterioration and maintenance problems. In order to resolve these problems, low impact development (LID) technologies that promote natural materials circulation are widely used. LID facilities are capable of treating heavy metals in the runoff by means of plant uptake; however, the uptake or phytoremediation capabilities of plants have not been studied extensively, making it difficult to select the most suitable plant species for a certain LID design. This study investigated the vegetative components of an LID facility, roadside plants, and plants in landscape areas with different heavy metal exposure and frequency to determine the uptake capabilities of different plant species. The plants harvested inside the LID facilities and roadsides with high vehicular traffic exhibited greater heavy metal concentrations in their tissues as compared with the plants in landscape areas. Generally, the accumulation of heavy metals in the plant tissues were found to be influenced by the environmental characteristics (i.e. influent water quality, air pollution level, etc.). Dianthus, Metasequoia, Rhododendron lateritium, and Mugwort were found to be effective in removing Zn in the urban stormwater runoff. Additionally, Dianthus, Metasequoia, Mugwort, and Ginkgo Biloba exhibited excellent removal of Cu. Cherry Tree, Metasequoia, and mugwort efficiently removed Pb, whereas Dianthus was also found to be effective in treating As, Cr, and Cd in stormwater. Overall, different plant species showed varying heavy metal uptake capabilities. The results of this study can be used as an effective tool in selecting suitable plant species for removing heavy metals in the runoff from different land use types.