• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.135-138
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• 2004

This paper considers a ring loading problem on RPR(Resilient Packet Ring), where RPR is recommended by IEEE802.17 Resilient Packet Ring working group for data optimized networks without the requirements of provisioning circuits. RPR is well suitable for metropolitan area network with two counter-rotating rings that multiple stations share the bandwidth, where the data and its corresponding control traffic is transmitted to the two opposite directional ring, respectively. One of the major concerns on RPR is to provide fairness among traffic requirements. The paper discusses several fairness measures and analysis ring loading problems for the fairness.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.602-607
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• 2004

Several countries such as Japan, France and so on gradually operate double deck trains as efficient, reliable and comfortable mass transportation systems. However, the double deck trains have relatively big cross sectional areas and high mass centers that cause unsafe vehicle running performances and interface problems between the vehicles and infrastructures, and do not have enough spaces for electric equipments. Therefore, prior to operate double deck trains on the existing lines in Korea, careful investigations should be performed. In this study, we have roughly designed a double deck EMU train system for the existing lines around Seoul metropolitan area.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2316-2321
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• 2009

With rapid development of world economics, electricity demand in metropolitan area has been increased dramatically. HTS(High Temperature Superconducting) cable is one of most promising technology to solve the bottleneck of electric network. However, HTS cable is not considered as matured technology yet to power system planners because of its different characteristics with conventional metal conductors. This paper suggests the comparison results of HTS cable simulation and experiment on steady state operation, also give the simulation results on transient characteristics of HTS cable components. This results could devote not only to discuss the security of HTS cable operation, but also to design power system oriented HTS cable.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.643-644
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• 2006

In this paper, WiBro system which is one of the mobile wireless metropolitan area network systems is presented. WiBro is an OFDMA system which has a sub-channelization process unlike conventional OFDM systems. The sub-channelization is the time consuming processing, so a time-efficient hardware architecture is needed. WiBro RAS(Radio Access Station) demodulator is designed with Verilog HDL, and the gate count is 81k using the $0.18{\mu}m$ processing.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.6
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• pp.111-121
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• 2016

This study was carried out to assess the riparian vegetation health in the fluctuation area and vicinity of reservoirs. The results of this study could be a basic data to improve the ecological function and establish green-network of waterside ecosystem. The study site is Daecheong lake reservoirs which the representative landscape of Geum river and with great number of visitors near metropolitan city. The 6 survey plots of 2 survey area were selected, survey area 1 had 4 survey plots and survey area 2 had 2 survey plots, and to compare the study results 4 control plots were selected in Gyeongcheon reservoir. The main dominant specie of survey sites was Salix koreensis in tree and subtree layer, were Salix koreensis and Salix glandulosa. in shrub layer. 2 survey plots of Samjeongdong and Kyeongcheon reservoir were assessed as 'Good', 2 survey plots of chudong were assessed as 'Fair' in vegetation health assessment. In the fluctuation area from flood water level to low water level, 58 populations of Salix koreensis were found in survey sites and Salix koreensis, Salix glandulosa and Acer tataricum subsp. ginale were found in control sites. The most adequate species at the condition affected by inundation impacts would be Salix koreensis and Salix glandulosa was more healthy at the area less affected by inundation. This study was carried out the vegetation health assessment on Daecheong reservoir which has been advanced natural succession for more than 30 years after the construction. Further, it should carry continuously out the research on the planting model of the waterside ecosystem for ecological restoration.

• Journal of Communications and Networks
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• v.5 no.3
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• pp.249-257
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• 2003

Ring networks are very commonly exploited among local area and metropolitan area networks (LAN/MAN), whereas cells or small fixed-size packets are widely used in synchronized ring networks. In this paper, we present an analytical method for evaluating the delay-throughput performance of a MAC protocol with multiple self-tokens in a slotted ring network under uniform traffic. In our analysis, we introduce the stationary probability, which indicates the number of packets in a node. Also, it is assumed that each node has a sufficiently large amount of self-tokens, and a slotted ring has the symmetry. The analytical results with respect to delay-throughput performance have similar values to computer simulated ones. Furthermore, in order to achieve fair access under non-uniform traffic, we propose an adaptive MAC protocol, where the number of self-tokens in a node dynamically varies, based on the number of packets transmitted within a specified period. In the proposed protocol, when the number of packets transmitted by a node within a specified period is larger than a specified threshold, the node decreases the number of self-tokens in a per-node distributed method. That results in creating free slots in the ring, thus all nodes can obtain an equal opportunity to transmit into the ring. Performance results obtained by computer simulation show that our proposed protocol can maintain throughput fairness under non-uniform traffic.

• Journal of Preventive Medicine and Public Health
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• v.56 no.4
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• pp.327-337
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• 2023

Objectives: Considering the importance of social determinants of health (SDHs) in promoting the health of residents of informal settlements and their diversity, abundance, and breadth, this study aimed to identify, measure, and rank SDHs for health promotion interventions targeting informal settlement residents in a metropolitan area in Iran. Methods: Using a hybrid method, this study was conducted in 3 phases from 2019 to 2020. SDHs were identified by reviewing studies and using the Delphi method. To examine the SDHs among informal settlement residents, a cross-sectional analysis was conducted using researcher-made questionnaires. Multilayer perceptron analysis using an artificial neural network was used to rank the SDHs by priority. Results: Of the 96 determinants identified in the first phase of the study, 43 were examined, and 15 were identified as high-priority SDHs for use in health-promotion interventions for informal settlement residents in the study area. They included individual health literacy, nutrition, occupational factors, housing-related factors, and access to public resources. Conclusions: Since identifying and addressing SDHs could improve health justice and mitigate the poor health status of settlement residents, ranking these determinants by priority using artificial intelligence will enable policymakers to improve the health of settlement residents through interventions targeting the most important SDHs.

• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.109-126
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• 2016

This study investigates the initiatives of Gangwon sea routes based on precedent studies on the North Pole route to suggest a multi-modal buildup of transport logistics network of Gangwon harbors for the strengthening of logistics efficiency in the Korean Peninsula. The findings were: First, the government should expand railway infrastructure in Gangwon. Second, harbors in Gangwon should each have one speciality to strengthen connection with other harbors by using railway oriented background transportation network. Third, the government should develop industries of EFEZ(East coast Free Economic Zone) in the East Sea Coast in Gangwon to connect resources from the North Pole Sea. Fourth, the government should invite the base of Araon Ho's polar research vessel to play the role of the North Pole Sea route in the near future. Fifth, the government should strengthen the role of the Samcheock LNG base under construction. SIxth, environment-friendly transportation technology should be introduced to reduce carbon emission as much as possible. Lastly, an optimum North Pole logistics route should be developed to connect the Metropolitan area(Metropolitan Economic Zone), Gangwon roads and railway, Gangwon habor, Trans-Siberian Railway and thw North Pole route, and Europe, to strengthen national foreign trade power in the near future.

• Journal of the Economic Geographical Society of Korea
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• v.6 no.1
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• pp.99-117
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• 2003

Major proposes of this study are to analyze Korean Shipbuilding's production network and cooperation between related firms and to understand their spatial features. The Geographical study about networks has focused on automobiles, electronics or communications industries. That's because those industries have distinctive spatial features thanks to the full growth of subcontract structures. The labor-centered, capital-centered shipbuilding industry, differently from other manufacturing industries, has production networks where outside trades are common. Today internet based communication is being reinforced and the flexibility of purchase circumstances is being positively proceeded. The central axes of the production network of Sumsung shipbuilding are internationally Europe and Asian area, nationally Busan and Gyeongnam province and Seoul Metropolitan areas, locally inside subcontracting firms. And In order to construct mutual trust with cooperation firms, Sumsung shipbuilding is trying to reinforce two-way cooperation relation through 'SungJoHoi' organized with outside subcontracting firms and 'inside cooperation firms conference'. In conclusion, Sumsung shipbuilding is trying to strengthen the competitiveness of shipbuilding industry, spatially by setting up the network through globalization-localization and functionally by constructing the partnership production network for mutual communication.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.961-970
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• 2009

This paper has attempted to improve the quality of urban environment in terms of the management of urban green tract and suggest a way of coexistence between human and nature by proposing a plan to establish green network using an urban green zone based on 'linear concept' instead of point and plane concepts. The results have turned out as follows: 1. According to current status of forest functions, forest recreation area has reached 39.6%, satisfying citizens' needs. However, the space for living environment is just about 20% with a lack of a green zone. Therefore, it's been necessary to establish green network using roadside trees and take advantage of them as sustainable living space along with existing green tract. 2. With forest in the suburbs and Geumhogang which is the tributary to the Nakdonggang, Sincheon (stream) flows through the downtown. It connects mountains including Waryongsan from the south to the north around Duryu Park and Dalseong Park. Therefore, the water system that passes through Palgongsan (Mt.) and Biseulsan (Mt.) would make it possible to connect with the parks in the downtown. 3. According to this paper, it appears that it's necessary to establish green network through roof or wall greening by focusing on the existing green tract in the urban parks and suburbs and taking advantage of roadside trees and water system.