• 한국전자파학회논문지
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• 제19권2호
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• pp.181-190
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• 2008

본 논문에서는 BPSK 수신기를 제작함에 있어서 기존에 사용하던 6-port 수신기를 대신하여 4-port 수신기를 이용할 수 있음을 제안한다. 위의 수신기를 제작함에 있어서 1 Mbps의 데이터 율을 가지는 임의의 신호를 입력으로 사용하였고, 중심 주파수는 2.45 GHz에서 동작하는 직접 변환 수신기를 제작하였다. 수신기의 비교기는 OPA-847을 사용하여 제작하였다. 위의 실험을 바탕으로 BPSK 수신기 제작에 있어서 4-port수신기의 동작 특성이 6-port 수신기 만큼의 효과를 나타냄을 보인다.

• Journal of Multimedia Information System
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• 제5권4호
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• pp.265-272
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• 2018

Busan is Korea's No. 1 trading port, and the logistics industry plays an important role in the regional industry as a whole. In Busan, various efforts are being made to revitalize the port logistics industry, but it is necessary to develop various policies and related technologies linked with the 4th industry. In this study, we propose a smart refrigeration logistics center, which is required for the activation of Busan New Port and the new port of Pusan New Port, which is connected with the 4th industry. I would like to present the operation direction of the center.

• 전기학회논문지
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• 제56권6호
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• pp.1105-1110
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• 2007

This paper describes an equivalent circuit modeling of 4-port connector system. A coupled transmission line was designed and fabricated, mimicking a 4-port connector system, and then S-parameters were measured using 4 port VNA (Vector Network Analyzer). The S-parameters from measurement and from Full-wave simulator coincided quite nice. By using these S parameters, an equivalent circuit parameters for a 4-port system was obtained. The time domain response from the equivalent circuit model matched to the signals, which was measured using TDR(Time Domain Reflectometry) meter. We were also convinced that there should be enough bandwidth to get a meaningful time domain result from Fourier inverse transformation of the S parameters. In addition, we applied the conversion algorithm to the 4-port connector system, which calculates the S-parameters of a 4 port system using the data from a 2-port VNA with the other ports open. Comparison of the two data, one from measurement and the other one from the conversion algorithm, was made in this manuscript.

• 한국위성정보통신학회논문지
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• 제4권2호
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• pp.52-56
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• 2009

본 논문에서는 그린 함수(Green's function) 방법을 이용하여 하나의 페라이트 디스크를 사용하는 4 단자 스트립라인 서큘레이터 설계 방법을 제안한다. 통신 시스템 설계의 유연성을 높일 수 있는 4 단자 서큘레이터는 이제까지 2개의 3 단자 서큘레이터를 연결하여 사용하고 있다. 이를 하나의 페라이트 디스크를 사용하는 4 단자 서큘레이터로 대체하면 무게와 부피를 감소시킬 수 있어서 위성용으로 장점을 갖는다.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.157-169
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• 1997

The effects of intake port eccentricity on the characteristics of in-cylinder swirl ratio in a 4-valve diesel engine having the two intake ports; one is a helical intake port and the other is a tangential intake port were investigated by using the ISM(impulse swirl meter) in steady flow test rig. Swirl ratio($R_s$) and mean flow coefficient($C_{f(mean)}$) with valve eccentricity ratio($N_y$) and axial distance(Z/B) were measured. As the results from this experiment, the characteristics of in-cylinder swirl ratio formed by a 4-valve cylinder head were largely affected by intake port eccentricity. There is a difference in the mass flowrate through the two intake ports, and the mass flowrate through the tangential intake port is 19% more than that of the helical intake port. Therefore, we could know that the effects of the mass flowrate ratio through each intake port besides intake port shape should be conidered.

• 한국항해항만학회지
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• 제33권4호
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• pp.263-270
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• 2009

Busan North port is facing crisis due to the opening of the New port. The North Port and NewPort are competing for a limited volume of cargoes and this competition is leading after all to price competition, lowering cargo work fee that may result in the failure of both This paper proposed the balanced development plans, which are the strategies of business tie-up and activation between the North Port and NewPort by introducing the strategy of "co-opetition" and the analysis for the success factor of co-opetition: to solve this operational problems on Busan port. It is found out that activation strategy is more successful co-opetition strategy than business tie-up strategy. The execution for the two co-opetition strategies will lead Busan Port to the balanced development as well as the enhanced competitiveness and will leap Busan port into global hub port as well.

• 한국산업보건학회지
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• 제32권4호
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• pp.449-455
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• 2022

Objectives: In order to provide basic data for future researchers, this study aims to explore future tasks after reviewing the changes in port safety management due to the enforcement of the Special Act on Port Safety. Methods: The provisions of the Special Act on Port Safety were analyzed and the latest literature related to port safety management was reviewed. Results: There are two major changes that have stemmed from the Special Act on Port Safety: 1. The scope of application for port participants has been expanded, safety education has been made compulsory, and safety management plans have been established and implemented for each business site. 2. The government is operating a port safety consultative body for each port and has hired one port safety inspector for each of the eleven local maritime and fisheries offices across the country. Future tasks include elaboration of port safety accident statistics, strengthening shipping companies' responsibility for stevedore safety, the unification of contracts, and government interest and support for port safety facilities. Conclusions: The primary feature of the Special Act on Port Safety is the emphasis on autonomous safety management by participants in port transportation. In addition, the enactment of the special law has allowed the Ministry of Maritime Affairs and Fisheries to actively intervene in port loading and unloading safety.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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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.

• 한국항해항만학회지
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• 제41권5호
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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.

• 통상정보연구
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• 제4권2호
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• pp.279-301
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• 2002

Lately, one of the most representative phases on business world is the diffusion of internet business. This change has been making new port business model called 'e-Port' in maritime transport. The focus of this article is to suggest some strategies on the implementation of e-Port in Korea. To research and analyze the e-Port realities, we first reviewed the previous study on Internet Marketing and e-Business. Six strategies that are critical on e-Port model were classified: (1) contents, (2) community, (3) commerce, (4) connection, (5) communication, (6) customization. Secondly, we chose and evaluated website of eight ports: Hongkong, Singapore, Antwerp, Hamburg, as successful e-port models. And then, we investigated actual conditions of e-Port in Pusan, Inchon, K wangwang, and Gusan. And then we try to find effective plan on the operation of e-Port.