• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.359-361
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• 2013

DGPS 기준국은 GPS 보정정보를 중파를 통해 실시간으로 송출하고 있다. DGPS 기준국의 감시를 위해 내륙감시국을 운영중이며 DGPS 기준국의 중파신호를 수신하여 감시하고 있다. 하지만 평창감시국에서 GPS 보정신호의 신호대잡음비(SNR) 저하가 발생하여 그 원인을 찾아보고 노이즈필터를 통해 해결하였다.

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.86-86
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• 2018

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.106-106
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• 2019

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.11-13
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• 2009

As the quantity of goods transported, port industry and inland transport industry have developing still, but almost 80% of inland transport industry consists of ground transport. According to issue "global warming", many regulations and agreements with countries in the world are becoming necessary and it is being fulfilled now. It is sure that Korea will have duty to reduce CO2 emission from 2013. And inland transport have to cut CO2 emission down. Therefore, this paper will address that calculate CO2 emission under route of transportation container at Korea by using O/D analysis. And then, it will predict routes of transportation containers which can reduce CO2 emission.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1344-1349
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• 2012

The Korean DGPS station transmits the 200 bps GPS enhancement signal using the MSK modulation in frequency range of 283.5 kHz to 325 kHz. The land-based stations of 6 sites provide the service area of 80 km with the output power of 500 W. The ocean-based stations of 11 sites provide the output power of 300 W, which provide the DGPS service to 185 kM. Some places are serviced from two or three DGPS stations. The interferences among the DGPS stations using the high power can be occurred. Also, the performances of the user terminasl in dual service area can be degraded. In this paper, the protection ratios for the DGPS service are defined. Using the MF wave propagation model, the interferences among the DGPS stations and the adjacent wireless ground stations are analyzed. Also, the performances of DGPS user terminals are analyzed in the viewpoint of interference.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.94-97
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• 2007

국내 CPS 수신환경에서 앙각별 DOP 및 측위 정밀도의 측정 ${\cdot}$ 분석을 통하여, DGPS 시스템의 24시간 안정적인 측위 정밀도를 제공할 수 있는 내륙 ${\cdot}$ 해양 기준국과 이용자 수신기의 적정 앙각을 제시하고자 한다.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.143-156
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• 2020

In Southern Vietnam, the competition among Inland Clearance Depot (ICD) has resulted in deconcentration tendencies and shifting share situations. However, related research on Southern Vietnam ICDs in particular and ICDs in Vietnam in general has been extremely limited. Hence, In this study, empirical research is conducted on ICDs located in southern Vietnam from 2010 to 2017. The throughput volume data of ICDs is analyzed by concentration indicators, namely the concentration ratio (CR), the Herfindahl-Hirschman Index (HHI), the Gini coefficient, the Lorenz curve, and the shift share analysis (SSA). The results of adopting all the methodologies indicate that deconcentration was the mainstream trend for ICDs in Southern Vietnam during the period of 2010-2017. The findings provide insights into the process of container terminal development and have academic and managerial implications. The strengthening of the competitiveness of Vietnamese container ports and ICDs could affect the competing Southeast Asian neighbors by facilitating the port of more shipping companies.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.77-78
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• 2022

Currently, communication at sea is more difficult than communication at inland due to the movement of route signs by waves. This paper conducts research on relay transmission and reception techniques to extend coverage in uplink situations. The uplink maritime communication environment between inland base stations and buoys located a certain distance inland was viewed as two hops, and a beam generated according to the number of antennas was selected and a performance analysis was conducted considering the movement of buoys measured by sensors.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.396-409
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• 2023

In the field of autonomous vehicles, where high accuracy and reliability are critical, various satellite navigation augmentation systems have been developed to improve system performance. These systems generate correction and integrity information based on measurements and navigation data collected from ground reference stations, enhancing user positioning accuracy. Thus, the performance of the system heavily relies on the deployment and spacing of reference stations. To construct an effective satellite navigation augmentation system, careful consideration must be given to the installation points of reference stations. This paper presents a user positioning performance modeling formula and proposes a method for selecting the installation points of new reference stations. The proposed method involves selecting a candidate group area that can optimize the user's positioning performance. By utilizing this method, the system's performance can be improved, ensuring high accuracy and reliability for autonomous vehicle applications.

• 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.