• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.10-17
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• 1996

A real time simple DGPS (SDGPS) for coastal survey is developed and in situ tested. While the accuracy of the system is almost the same as that of existing commercially available DGPS, it is very economical compared to the commercial ones. The RMS error of the positions fired by the system is estimated to be less than 2 m within the range of 30 km from the reference station. Even if the coordinates of the reference station are uncertain, they can be fixed, from the continuous GPS observation of one day, with the maximum error less than 1 m. The system is believed to be helpfully utilized to most of coastal surveys despite of some minor defects.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.231-236
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• 2016

The stability of DGPS signal in the DGPS service area was measured and the service availability according to the receiving signal strength was analyzed in this paper. Based on the effects of radio wave propagation in the seasons of winter and summer, daytime and night, the method to provide the DGPS service coverage was presented in this paper. The signal's strength of DGPS radio wave were measured at a constant distance from the DGPS reference station during a constant period. The propagation of DGPS radio wave is affected by status of ground conductivity, so the DGPS service area is dependant on the ground conductivity. To provide the stable service coverage, it is necessary to apply the adaptive power control for receiving signal's variations and the antenna design for alleviation of high elevation's radiation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2249-2260
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• 2017

IMO (International Maritime Organization) has been providing GMDSS (Global Maritime Distress and Safety System) and mandating to install distress and safety systems according to SOLAS. Digital-HF(High-Frequency) coast station communication system maintains interoperability between ship and coast station and digital data exchange in maritime mobile service by digitizing existing analog base voice communication. In this paper, we analyze ITU-R M. 1798-1 established by ITU for digital HF communications and propose Advanced annex2 and new Annex 5 to improve the problems of the existing Annex 2 and Annex 4. The proposed OFDM protocol basically adopts ARQ (Automatic Retransmission Request) which retransmits when an error occurs in a half-duplex manner between an information transmitting side (ISS) and an information receiving side (IRS) and we propose a digital HF communication system and its operational concept which is more reliable and superior than the existing ITU-R M. 1798 by implementing technical development on implementation and performance improvement.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.355-362
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• 2009

In this paper, the author carried out the study to develop oil spill response training courses for competent responders examining IMO guidelines and response training courses of developed maritime countries as well as Korea. According to a result of study, fundamental training courses are to be established on the basis of IMO guideline, and also to prepare pre-arranged brief course like Basics of Spill Response for beginner. The courses should be step-by-step related with mutual continuous contents, and more times are given to on-site training for basic course and to classroom lecture with desk-top exercise for advanced course. Besides, SCAT shall be added to shoreline cleanup course, finally it is advisable that total 9 types of courses are established with additional refresh course.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.17-24
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• 2009

In this paper, the authors carried out the study to develop oil spill response training courses for competent responders examining IMO guidelines, response training courses of maritime development countries and Korea response. According to a result of study, fundamental training courses are to be established on the basis of IMO guideline, and also to prepare pre-arranged brief course like Basics of Spill Response for beginner. The courses should be step-by-step related with mutual continuous contents, and more times are given to on-site training for basic course and to classroom lecture with desk-top exercise for advanced course. Besides, SCAT shall be added to shoreline cleanup course, finally it is advisable that total 9 types of courses are established with additional refresh course.

• Korea Trade Review
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• v.43 no.4
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• pp.155-175
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• 2018

This study estimates the technical efficiency and total factor productivity(TFP) of and analyzes the relationship between TFP and exports for Korean manufacturing companies from 2000 to 2016. Specially, TFP is decomposed into Technical Change(TC), Technical Efficiency Change (TEC), and Sale Effect(SE), and compared between large and small enterprises. First, in the case of technical efficiency, the Korean economy has been very vulnerable to external shocks, such as the sharp decline following the 2008 financial crisis. The efficiency of the electronics, automobile, and machinery sectors is low and needs to be improved. In addition, the technological efficiency of large enterprises is higher than that of SMEs in most manufacturing sub-sectors except for non-ferrous metals. In the case of TFP, most changes are due to TC, and the effective combination of labor, capital and the effect of scale have little effect, suggesting that improvement of internal structure is urgent. In addition, volatility due to the impact of the financial crisis in 2008 was much larger in SMEs than in large companies, so external economic impacts are more greater for SMEs than large enterprises. The relationship between TFP decomposition factors and exports shows that TC has a positive effect only on exports of SMEs. Therefore, in order to increase exports, in the case of SMEs, R&D support to promote technological development is needed. In the case of large companies, it is necessary to establish differentiated strategies for each export market, competitor company, and item to link efficiency and scale effect of exports.

• Journal of the Korean association of regional geographers
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• v.21 no.1
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• pp.114-136
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• 2015

Manufacturing FDI is mainly conducted by establishing production firms in the host country. The foreign branch facilities which are closely connected to headquarters in the home countries through the global supply chain have decisive effects on the integration of global production system and on the pattern changes in international logistics. Therefore, the study on the development process of manufacturing supply chain through FDI can be the key factor to understand the global production and international logistics system. This study analyzes the spatial and temporal patterns of direct investments in China by Korean companies in the manufacturing sectors. The results show a great deal of differential in periods and regions in investment. At the early period of Korean manufacturing FDI, the coast provinces in China which are adjacent to Korean peninsula were main investment target regions. However recently, coastal and inland provinces far away from Korea have been important for attracting Korean manufacturing capital. If further affiliated studies are done, the results of this study would be more beneficial to understand the logistics flows of regional supply chain based on the manufacturing FDI.

• Spatial Information Research
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• v.13 no.3 s.34
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• pp.323-333
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• 2005

This paper shows disposal site about an airport using ICAO(International Civil Aviation Organization)and GIS(Geographic Information System). In Korea, mountains occupy above $70\%$ of the whole country centering around Baek-Du mountain range and a physical distribution system doesn't go on smoothly between east and west region. At present, disposal site about an airport follows the standard of ICAO and FAA(Federal Aviation Administration). So, it's desperately necessary to make the new standard suitable for the condition of Korea. This study analyzes major customers in the aerospace and transportation sector by considering the present condition of location of geography, atmospheric phenomena, population and transportation about Ul-Jin airport on the standard of ICAO and FAA. As the results, Gi-Sung site proposed for the airport using the existing a runway in air force has a locality road connecting a fishing and agrarian villages and is shown better than the others.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.17-35
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• 2016

Earthquake-induced disasters are often more severe in locations with soft soils than firm soils or rocks due to differences in ground motion amplification. On a regional scale, such differences can be estimated by spatially predicting subsurface soil thickness over the entire target area. In general, soil deposits are generally deeper in coastal or riverside areas than in inland regions. In this study, a coastal metropolitan area, Incheon, was selected to assess site effects and provide information on seismic hazards. Spatial prediction of geotechnical layers was performed for the entire study area within the GIS framework. Approximately 7,000 existing borehole drilling data in the Incheon area were gathered and archived into the GIS Database (DB). In addition, surface geotechnical data were acquired from a walkover survey. Based on the built geotechnical DB, spatial zoning maps of site-specific seismic response parameters were created and presented for use in a regional seismic strategy. Site response parameters were performed to determine site coefficients for seismic design over the entire target area and compared with each other. Site classifications and subsequent seismic zoning were assigned based on site coefficients. From this seismic zonation case study in Incheon, we verified that geotechnical GIS-DB can create spatial zoning maps of site-specific seismic response parameters that are useful for seismic hazard mitigation particularly in coastal metropolitan areas.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.10-27
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• 2014

HAZUS-MH is a GIS-based computer program that estimates potential losses from multi-hazard phenomena: earthquakes, floods and hurricanes. With respect to seismic disaster, characteristics of a hypothetical or actual earthquake are entered into HAZUS. Then HAZUS estimates the intensity of ground shaking and calculates the correspondent losses. In this study, HAZUS was used as a part of the preparations of the future seismic events at a coastal plant facility area. To reliably characterize the target facility area, many geotechnical characteristics data were synthesized from the existing site investigation reports. And the buildings and facilities were sorted by analyzing their material and structural characteristics. In particular, the study area was divided into 17 blocks taking into account the situation of both land development and facility distribution. The ground conditions of blocks were categorized according to the site classification scheme for earthquake-resistant design. Moreover, seismic fragility curves of a main facilities were derived based on the numerical modeling and were incorporated into the database in HAZUS. The results estimated in the study area using HAZUS showed various seismic damage and loss potentials depending on site conditions and structural categories. This case study verified the usefulness of the HAZUS for estimating earthquake losses in coastal facility areas.