• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.125-130
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• 2008

The main components of the KSTAR helium refrigeration system (HRS) can be classified into the warm compression system (WCS) and the cryogenic devices according to the operating temperature levels. The WCS itself consists of the compressor station (C/S) and the oil removal system (ORS). The process helium is compressed from 1 bar to 22 bar maximum in the C/S and downstream, the ORS removes the oil mixed in the helium to less than 10 ppbw as per the operation criteria of the cryogenic devices of the KSTAR HRS. After the installation, the pre-commissioning and commissioning activities were started on July, 2007. Before the start-up of the C/S, vibration measurement and the skid reinforcement jobs were performed for stable operation of the C/S. The results of the WCS performance tests met the requirements of the KSTAR HRS but satisfied the vibration level criteria only at the compressors' full load condition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1075-1082
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• 2016

In order to calculate the optimum installation interval between a speed hump and hump type crosswalk that are installed continuously in succession, this study examined the speed of a vehicle that passes different intervals between speed humps and hump type crosswalks from the approach section of a roundabout having a maximum speed limit of 30km/h; analyzed the effects of speed humps and hump type crosswalks installed continuously in succession on vehicle driving speed; and simulated the optimum installation height of hump type crosswalk. As a result, the following conclusion was drawn. First, it was found that the optimum interval between a speed hump and hump type crosswalk, which are the representative traffic calming techniques for reducing vehicle speed, to control vehicle speed under 30km/h is 30m. Second, as a result of comparing the deceleration of a vehicle that pass hump type crosswalks, it was found that if the installation interval is 65 m and above, a speed hump and hump type crosswalk had no effect. Therefore, it is desirable that the maximum installation interval between a speed hump and hump type crosswalk for controlling vehicle speed within a fixed road section should not exceed 65m. Third, the analysis showed that the optimum installation height of hump type crosswalk is 6-8cm in case vehicle speed at the approach section is 20km/h or lower, 8-10cm in case of 30km/h, and 10cm in case of 30km/h or higher, respectively. Fourth, even at a road section on which a speed hump and hump type crosswalk are installed, speed reduction effects may sometimes be insignificant due to a driver's studying effect, traffic conditions and so on. Thus, it is judged that speed reduction effects will be greater if several traffic calming techniques such as speed hump, chicane, and choker are applied at the same time. Therefore, in case of applying traffic calming techniques for the purpose of reducing vehicle speed in order to promote pedestrian safety, the composite application of several techniques should be considered.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.122-129
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• 2020

Surion is required to install radios (U/VHF-AM, VHF-FM) capable of omni-directional communication. Therefore, this paper demonstrates the antenna performance test for the installation of the Surion communication antenna and the selection of optimal location. A simulation pattern analysis was performed employing the antenna, and a coupling test was performed by creating a new evaluation criterion. In addition, the results of the pattern flight test conducted at the previously suggested 1:20 turn and separation distance ratio were observed to be normal. However, the occurrence of voice cutoff was noted in the long-distance flight test. Therefore, in this paper, 1:300 (15 NM) is proposed as a new optimal ratio for predicting the long-distance flight test results in advance. Finally, the effectiveness of the proposed evaluation criteria was verified through long-distance flight tests. Consequently, it is expected to reduce the development schedule and cost by reducing the trial and error of the performance test for the Surion model. Also, the results of this study are expected to be used as standards for the installation of communication antenna and quality tests for other helicopters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.877-886
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• 2019

The size of the subway entrance should be calculated according to the user's demand, but Korea has the same size for each entrance by applying a uniform value. Recently, the installation of mobile convenience facilities such as escalators, elevators, etc. is mandated by the traffic weakness promotion law, but it is inconvenient to use the existing stations because it is mainly arranged in the place where it can be installed regardless of user demand. This study aims to establish a model for estimating the size of mobile convenience facilities by predicting the use demand of each station entrance so that the location and size of mobile facilities can be reflected in the design or construction of the station. To this end, a multiple regression model was established to forecast daily demand by utilizing the demand for getting on and off by station and the building association area for each purpose around the railway station. The actual data of Dongdaemun and Jonggak Stations were used to verify the estimated model. In addition, the escalator installation scale was compared / analyzed by doorway using domestic and overseas escalator equations. As a result, it was more accurate to estimate the usage demand for a single station. Also, Jonggak Station has an up and down escalator installed at exit 1, but it was analyzed that it is appropriate to install at exit 4. This study is an advanced form of the essay model for estimating the users of the entrance and exit users of urban railway stations published in 2018. In addition, it seems to be the basis of the current escalator installation criteria.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.345-354
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• 2009

The review of statements and coastal development characteristics in South Korea were diagnosed by the consultation on the coastal area utilization in Korea. The occupation and the use of public water were dominated by installation of coastal structure and seawater supply and drainage whereas the reclamation areas were predominantly utilized for developing industrial complex, harbor, fishing port and road. The occupation and the use were dominant in western coast, but reclamation was dominant in southern coast of Korea. The number of utilization cases was particularly greater in Jeonnam, Gyeongnam, and Gyeonggi Province including Incheon. The number of the statements reviews increased by more than 200 cases in 2008 compared with 2007, and most of them were the simple statements. The statements related to ocean disposal of dredged sediment, reclamation, dredging sediment, seawater supply and drainage, and marine sand mining were submitted for review. Coastal utilization was especially active in the regions of seawater quality criteria I and II. In particular, special management sea areas designated under the relevant marine regulations were utilized mostly by reclamation for developing harbor, fishing port and coastal structure. Development activities in national parks comprised primarily structure installation and coastal maintenance. In the fisheries resources protection areas, 40% of the total cases accounted for coastal maintenance, 31% for structure installation, and 16% for seawater supply and drainage. In addition, alternative plans for the improvement in policies and system of marine environmental impact assessment were suggested to enhance the function and confidence of the consultation on the coastal area utilization in Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.662-669
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• 2018

Recently, the installation of submarine power cables is under consideration due to the increase of electric power usage and the development of the offshore wind farm in island areas, including Jeju. In order to protect power cables installed on the seabed, it is necessary to calculate the burial depth based on the characteristics of anchoring, dragging and fishing, etc. However, there is no design standard related to the size of target ships to protect the cables in Korea. In this study, we analyzed the design standards for the protection of domestic submarine pipelines similar to submarine cables, and developed the risk matrix based on the classification by emergency anchoring considering the installation environment, then designed the size of target ships according to the cumulative function scale by ship size sailing through the sea concerned. Also, we linked marine accident conditions, such as anchoring, dragging, etc. and the environmental conditions such as current, sea-area depth of installation etc. to the criteria of the protection of submarine cable, and examined the size of specific target ships by dividing the operating environment of ships into harbor, coastal and short sea. To confirm the adequacy and availability of the size of target ships, we verified this result by applying to No. 3 submarine power cables, which is to be installed in the section from Wando to Jeju Island. This result is expected to influence in the development of a protection system for submarine cables and pipelines as well as the selection of anchor weight according to the determination of burial depth.

• KIEAE Journal
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• v.12 no.5
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• pp.63-70
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• 2012

In order to set the direction of providing facility for the utilization of castle heritage, as well as to establish the method for securing access and determine installation criteria in consideration of preservation environment, an analysis was carried out on the cases of having secured access for people with disabilities in England for the advanced utilization of castle heritage. As the result of the analysis, the planning factors of the facility for people with disabilities in England for the utilization of castle heritage were deduced as follows: 1) The plan for facility was focused on the disabled using wheelchairs and visually impaired persons, rather than on services for hearing-impaired persons and people with learning disability. 2) As for audience movement line plan, regular route was used for audience movement line to lead them in a single direction. 3) As for the provision of prior access information, 3 stepwise access grades were established for the facility information plan of heritage. 4) As for information service by disability type, models were provided; and complementary explanation was provided by using text, drawing, picture, video and voice. 5) Rest spaces were secured where audience could look out upon castle heritage. For the utilization of castle heritage, it is necessary to develop planning factors of the facility design for people with disabilities according to its characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4871-4877
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• 2015

This article presents a circuit and a system for IEEE 1588 based clock synchronization to generate a very accurate frequency signal required in femtocell devices. A prototype board and the experimental environment to verify the functions and to evaluate the performance are explained to verify the feasibility of the proposed synchronization system. To make low-cost femtocells without constraints on the place of installation, it is very important to study on the practical implementation of synchronization system based on IEEE 1588. The experimental result shows that the synchronization errors between -16 ns and 9 ns are guaranteed over the network of femtocell devices with the proposed synchronization circuits, thus the synchronization criteria of the 3GPP HNB are met.

• Journal of Environmental Science International
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• v.24 no.10
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• pp.1239-1251
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• 2015

Impervious areas have been expanded by urbanization and the natural structure of water circulation has been destroyed. The limits of centralized management for controlling storm water runoff in urban areas have been suggested. Low impact development (LID) technologies have been promoted as a crucial alternative, establishing a connection with city development plans to build green infrastructures in environmentally friendly cities. Thus, the improvement of water circulation and the control of nonpoint source were simulated through XP-SWMM (storm water and wastewater management model for experts) in this study. The application of multiple LID combination practices with permeable pavements, bioretention cells, and gutter filters were observed as reducing the highest runoff volume by up to 70%. The results from four different LID installation scenarios indicated that permeable paving is the most effective method for reducing storm water runoff. The rate of storm water runoff volume reduced as the rainfall duration extended. Based on the simulation results, each LID facility was designed and constructed in the target area. The LID practices in an urban area enable future studies of the analysis of the criteria, suitable capacity, and cost-efficiency, and proper management methods of various LID techniques.

• Journal of Soil and Groundwater Environment
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• v.20 no.6
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• pp.8-18
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• 2015

Pollutants such as heavy metals and explosives originating from the military operational ranges can be migrated to adjacent surface water body or offsite soil, and can affect to local residents and aquatic ecosystem. Therefore, Korea Ministry of the National Defense has established various guidelines for environmental management including the installation of pollutant migration prevention facilities (PMPFs) and monitoring methodologies for heavy metals in the operational range soil and effluent and sediment of PMPFs. However, current guidelines neither address the explosive compounds such as 2, 4, 6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) nor suggest detailed environmental investigation protocol. This paper introduces the new “Environmental Management Manual for Military Firing Ranges”, which includes the environmental criteria for explosives as well as the detailed investigation protocol for the affected environmental media including soil, effluent and sediment of PMPFs.