• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.276-281
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• 1989

Comparison 3-port servo system with 4-port is made to obtain optimal design for heavy and unidirectional hydraulic system, It is concluded that 3-port servo system it more adequate than 4-port for the heavy load system which is usually operated at lower frequencies. High performance electro-hydraulic position controller is designed using 3-port servo valve. It includes dynamic pressure feedback as a inner loop and position feedback as a outer loop.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.91-96
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• 2008

In this paper, a monopulse fled for three mode $2{\times}2$ array feed horn antenna was designed. Gain of single feed was 8.25dB. Increasing property of gain and rectangular waveguide and reflection of free space is decreased because it has structure extending to electric plane at connected part from transformation to free space. When fled port1 and port2 is placed vertically and thickness of aperture hem is reduced, isolation is satisfied with property of lower -25dB. Also, at higher frequency, it is confirmed that isolation is improved. Combination of electric field occurs less influence because port1 and port3 is placed horizontally and distribution of electric field is connected to parallel. However, because of combination of electric field, it is more improved from 2dB to 6dB than isolation of port1 and port2. Direct combination occult less effect at port1 and port4 than effect of port2 and port3, it is lower -35dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.414-419
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• 2008

The six-port correlator is comprised of a power divider and three hybrid couplers. In this paper, the six-port phase correlator using three-arm branch $90^{\circ}$ hybrid coupler were designed with the center frequency of 11.85 GHz. The performances for the six-port phase correlator was analyzed by using ADS2003A tool. Three-arm six-port phase correlator provides more wide dynamic frequency range than that of six-port using the conventional hybrid coupler in range of circa five times, which is range of 10.8 to 12.3GHz (1.5 GHz). The phase errors among the output ports of the six-port phase correlator are below $5^{\circ}$. The six-port Phase correlator was fabricated to evaluate the Performance of the proposed six-port phase correlator. The measured performance of the six-port phase correlator shows the good accordance with the simulation data.

• Journal of Korea Trade
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• v.27 no.3
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• pp.65-86
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• 2023

Purpose - As globalization progresses, complexity also increases, and various factors that threaten port functions are emerging. Accordingly, the demand for port security to prevent the crisis and resilience that quickly recovers its original function after the crisis is also increasing in port operations. However, few studies have examined how to ensure the port security and how the resilience affects operation performance of port and sustainability performance as well. So the study aims to find out how port security affects port resilience and port operational performance, and consequently, this two factors affect socioeconomic and environmental sustainability performance respectively and synthetically. Design/methodology - Confirmatory Factor Analysis (CFA) was first performed to determine the validity of the factors of model and hypothesis test was performed using Structural Equation Model (SEM) to analyze the Port Performance Model, which show the perception logic among port security level, port resilience, operation performance, and sustainability performance. In order to empirically analyze this model, total 264 respondents from port security operators, shipping companies in South Korea were surveyed. Findings - As result of SEM, First, port security level positively affected the resilience (H1) and cargo operational performance (H2) but not in both of the sustainability performances (H3, H4). Second, resilience positively affected only cargo operational performance (H5) and socio-economic sustainability performance (H7). Last, cargo operation performance positively affects the both of sustainability performances (H8, H9). Originality/value - It was confirmed that port security could improve cargo operational performance through ensuring port resilience and eventually increase the socio-economic sustainability. Therefore the study implies that careful integration and management of port security, port resilience, and sustainability are required, along with compromise on sustainable development goals in the social, economic, and environmental area among all stakeholders.

• Journal of Power System Engineering
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• v.16 no.6
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• pp.92-97
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• 2012

In this study, ER fluids were working fluid and yield shear stress of attained dispersive ER fluids made by analyzed to adapt effectively at the practical equipment like three port ER valve. In addition, movement of ER particle was observed by using a microscope the same as the strength of electric field with Bingham characteristic. Basis material was presented to develop 3 port ER-Valve by quantitatively comparing and analyzing entrance, load and outlet flow's differences of 3 port rectangular tubes. This study, after designing and producing the 3port ER-Valve, considered the characteristic of pressure drop, outlet and load flow rate by changing the strength of electric field on ER fluids flowing between electrodes.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.3
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• pp.138-151
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• 2023

Korea's port infrastructure is rapidly aging, with old port facilities with more than 30 years of public life expected to surge from about 23% in 2019 to 47% in 2029. Traditional, aging ports lose competitiveness in logistics processing, reducing development around the port and increasing human casualties due to the human resource-based maintenance of the facilities. Therefore, it is necessary to solve this problem by establishing systematic management technology based on a digital twin. This research aimed to present the specific implementation steps of a digital twin reflecting smart port technology through cases of port infrastructure disasters, aging status, and smart ports. The study analyzed the port infrastructure linkage system and created and mapped scenarios essential for digital twin implementation. Three-dimensional (3D) modeling and simulation data for disaster and aging management among existing port infrastructure systems were collected. A digital twin port was implemented with 3D modeling. It implements a port digital twin simulation that links data such as sensing data and image data acquired from the port infrastructure in real time. Implementing a digital twin port for port infrastructure disasters and aging management can secure predictive port infrastructure management and disaster safety

• Journal of Navigation and Port Research
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• v.40 no.2
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• pp.57-65
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• 2016

The port throughput situation has changed since the 2008 financial crisis in the US. Therefore, we studied the situation, accurately estimating port traffic of Korean port after the 2008 financial crisis. We ensured the proper port facilities in response to changes in port traffic. In the results of regression analysis, Korean GDP and the real effective exchange rate of Korean Won were found to increase the container throughput in Korean and Busan port, as well as trade volume with China. Also, the real effective exchange rate of Korean Won was found to increase the port transshipment cargo volume. Based on the ARIMA models, we forecasted port throughput and port transshipment cargo volume for the next six years (72 months), from 2015 to 2020. As a result, port throughput of Korean and Busan ports was forecasted by increasing annual the average from about 3.5% to 3.9%, and transshipment cargo volume was forecasted by increasing the annual average about 4.5%.

• Journal of Navigation and Port Research
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• v.41 no.5
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• pp.353-358
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• 2017

This study aims to propose an assessment tool of port service quality (PSQ) in the context of container transport logistics (CTLs), by taking the perspectives from port users. The CTLs defined in this study are the relevant activities of serving the physical flows of a container box from a point of origin via a container port to a point of destination. To address the ports' role in collaboration between its channel members in CTLs, the PSQ measures for all port user groups (i.e. common PSQ measures) are selected based on the relevant CTLs activities involved by port, and its users within terminal/port area as well as throughout the CTLs chain. An importance-performance analysis (IPA) is applied as a diagnostic tool to analyse the status quo of Busan Port in CTLs contexts, by comparing the importance and performance (IP ) scores against each individual CTLs criterion. The findings from the IPA reveal that port managers and policy makers at the Busan Port should concentrate on six PSQ measures (i.e. SR1, SR4, ITS1, VAS1, VAS4, ICI3) to enhance PSQ in CTLs. However, four measures (i.e. ITS2, ITS3, ITS4, VAS2) are identified as a possible overkill, indicating an area of inefficiency where a remedial action of the cost-cutting decision is necessary. On the other hand, the Busan port shows an outstanding performance on four measures such as SR2, SR3, ICI1 and ICI2. The measures are not only important but also high performance. The study findings provide managerial guidance to port managers in Busan Port, in view of searching for managerial and operational strategies for sustainable port growth.

• Journal of Distribution Science
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• v.14 no.1
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• pp.29-38
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• 2016

Purpose - The purpose of paper is to review and look into the process of port development of each country, and compare with their system of port management. Research design, data and methodology - The methods to be taken is to examine a process of port development in terms of historic and regulated point of views, and each country's port is compared with various port models. Results - China has evolved of port governance into 3 stages, which has lead to almost liberalized port management system in process of privatization slogan. Japan has three stages of port development, and key commitments have been done by local government, rather than national one. Korea has also several stages of port reforms, and national government has been deeply involved in port industry, as well as regional government and port authority in certain areas. Conclusions - whatever port management system each countries has taken, it eventually aims to port productivity in country's port. To adopt most proper port management system may be answer for country to cope with environmental changes around port industry.

• Journal of Korea Port Economic Association
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• v.21 no.3
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• pp.35-59
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• 2005

The Purpose of this study is to exmaine fundamental problems of Gwangyang Port and draw up plans of its Hub Port. Gwangyang Port has been gradually reduced container cargo increase rate. on account of large development of Chinese Port, undevelopment of Hinterland, Port facilities of Gwangyang Port. We should develop hinterland to be closely connected with Port Cluster, Business City, Free Economic Zone to increase cargo volume. and in order to increase transshipment cargo volume, We should prepare diverse plans that can induce Chinese and Japanese transshipment cargo. Gwangyang Port and Busan Port should be managed united one port system by a Port Authority to strengthen international competitiveness. Activation of new ports for the most part call for full support by Government at the beginning. Gwangyang Port's future it can be if Government has strong will.