• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2010년도 춘계학술대회
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• pp.154-155
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• 2010

본 논문에서는 end-fire 방사패턴 특성을 가지는 2.4GHz ISM 밴드용 소형 open-end slot 안테나를 설계하였다. 안테나 설계 공간은 $23mm{\times}15mm$의 좁은 영역으로 한정된 공간 내에 안테나를 설계하기 위하여 한번의 Bent된 slot을 도입하였고, End-Fire 방사특성을 내기위해 안테나 수평면상의 위쪽 방향으로 slot을 open시킨 구조이다. Bent된 slot을 이용해 전체 slot의 길이를 변화시키지 않고 주파수의 조절이 가능하고, Feeding Line의 길이와 폭을 조절하여 보다 광대역의 특성을 얻을 수 있었다. 제작된 안테나의 공진 주파수는 2.46GHz이고 대역폭은 2.4GHz~2.61GHz 까지 약 210MHz(VSWR<2) 이다. 방사패턴은 동작 주파수 내에서 slot이 open된 방향으로 end-fire특성을 가지고, 안테나의 이득과 효율은 각 각 1dBi, 70% 이상의 성능을 가진다. 설계 결과의 검증을 위해 모의실험 결과와 측정 결과를 비교하여 제시하였다.

• 한국항행학회논문지
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• 제25권3호
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• pp.229-235
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• 2021

본 논문은 단락 또는 단선 스터브가 연결된 전송선로를 이용하여 높은 분배 비율을 갖는 비대칭 전력 분배기를 구현하는 방법을 제안하였다. 제안된 방법은 2포트 전송선로 중앙에 임의의 임피던스로 변환할 수 있도록 별도의 포트를 추가한 3포트 전송선로와 단선 또는 단락 스터브가 각 포트에 병렬로 연결된 3포트 전송선로를 등가회로로 보고 회로를 해석한 것이다. 이러한 방법의 타당성을 증명하기 위해서, 분배 비율 k² = 20 dB를 갖는 윌킨슨 전력분배기와 k² = 17 dB를 갖는 Gysel 전력분배기를 3포트 전송선로 등가회로를 이용하여 중심주파수 1 GHz에서 설계하였으며, 전기적 특성의 실험 결과는 시뮬레이션과 잘 일치함을 확인하였다.

• 한국항만경제학회지
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• 제20권2호
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• pp.89-100
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• 2004

Because of a recent trend of the open and globalized world economy, international trade is getting bigger and there is a trade competition among many countries, resulting in competition between harbor industries. Therefore, as hub-port development of China, Japan and Taiwan is more actively progressing than any other times, Korea should prepare a powerful management system to take the initiative over them. Above all, a new recognition of the governmental officers in charge of political management about hub-port industry and early development of the northeast hub-port are needed. To maximize its distinctiveness from competitive ports, port sale should be actively managed. As well, as port functions are diverse, accompanied site development should be prepared. In conclusion, in order to improve functions of a port and develop the port as a general complex of physical distribution, the government should encourage the accompanied site development and support preparation of a customs-free area and a general system of physical distribution.

• 유통과학연구
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• 제13권2호
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• pp.5-13
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• 2015

Purpose - In recent years, concerns over privatization have been growing in some public sectors. Privatization in Britain offers lessons for those who have intended to privatize their industry, and in particular, the port industry. Therefore, it is useful for researchers to examine British port privatization in detail, particularly the implications of UK port privatization. Research design, data, and methodology - After reviewing the historical development of the UK port industry, the important factors determining the success of the British port privatization process were identified. The interpretations could be lessons for some other country to consider port privatization in near future. Results - The key factors in relation to port privatization are first, regulation; second, ownership; and third, utilities and operations, which includes autonomy, efficiency, and competitiveness. In addition, the UK port management system is a pure private port system, which has been successful. Conclusions - In Britain, after deciding to privatize the erstwhile public ports, they were fully privatized, focusing on the aforesaid key factors. This offers important lessons for the privatization of other ports in the world.

• Asian Journal of Business Environment
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• 제6권1호
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• pp.13-17
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• 2016

Purpose - Purpose of paper is to clarify this PPP((Public Private Partnerships)'s essence and advantages as well as disadvantages, and then it will take it out some conclusions and implication together. To do so, PPP should be examined carefully and then landlord port will be investigated in view of PPP, then, it will give some implications whether or not PPP is successful to apply more port in concern. Research Design, data, and methodology - The methodology that I take is to look into both PPPs and then to look intp landlord port in view of PPP. By doing so, it can be more understandable to PPP in port industry. Results - It can be found that landlord port system is more valuable and applicable instrument to adapt for port competitiveness and productivity, which leads to efficient port management. Conclusions - Landlord port system is an alternative instrument to be apply to port management in terms of PPP, and it has been justified that many worldclass port has taken this landlord port management system.

• 대한전기학회논문지
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• 제38권2호
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• pp.144-150
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• 1989

The competitive power extraction problem in a linear n-port network consisting of resistances and independent sources with the same frequency is solved. For solving the problem, the definition of the two-port image impedances is extended to the n-port image impedances. In a competitive power extraction from an n-port network, the load resistances eventually approach the image resistances been found to be between the reciprocal of the short circuit conductance and the open circuit resistance.

• Journal of Yeungnam Medical Science
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• 제37권4호
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• pp.308-313
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• 2020

Background: Hysterectomy is one of the major gynecologic surgeries. Historically, several surgical procedures have been used for hysterectomy. The present study aims to evaluate the surgical trends and clinical outcomes of hysterectomy performed for benign diseases at the Yeungnam University Hospital. Methods: We retrospectively reviewed patients who underwent a hysterectomy for benign diseases from 2013 to 2018. Data included the patients' demographic characteristics, surgical indications, hysterectomy procedures, postoperative pathologies, and perioperative outcomes. Results: A total of 809 patients were included. The three major indications for hysterectomy were uterine leiomyoma, pelvic organ prolapse, and adenomyosis. The most common procedure was total laparoscopic hysterectomy (TLH, 45.2%), followed by open hysterectomy (32.6%). During the study period, the rate of open hysterectomy was nearly constant (29.4%-38.1%). The mean operative time was the shortest in the single-port laparoscopic assisted vaginal hysterectomy (LAVH, 89.5 minutes), followed by vaginal hysterectomy (VH, 96.8 minutes) and TLH (105 minutes). The mean decrease in postoperative hemoglobin level was minimum in single-port LAVH (1.8 g/dL) and VH (1.8 g/dL). Conversion to open surgery or multi-port surgery occurred in five cases (0.6%). Surgical complications including wound dehiscence, organ injuries, and conditions requiring reoperation were observed in 52 cases (6.4%). Conclusion: Minimally invasive approach was used for most hysterectomies for benign diseases, but the rate of open hysterectomy has mostly remained constant. Single-port LAVH and VH showed the most tolerable outcomes in terms of operative time and postoperative drop in hemoglobin level in selected cases.

• 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.

• 유통과학연구
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• 제15권1호
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• pp.7-14
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• 2017

Purpose - The purpose of the paper is to examine development strategy that Shanghai port has practiced, and to take out some productive implications to be applied to other port. Research design, data and methodology - The research methods to be applied is first to look into some development progress in terms of trade volumes, and then to review development strategy that is classified with two different aspects, and finally to identify implications. Results - Following the change of economic environment that China has joined to WTO, the way of doing business in Chinese economy has transferred to market economy more closely. Trade volume is higher than before and it attracts to build national infrastructure including port. Development strategy has to be needed to take care of newly faced economic situations, within two aspects, hardware and software approach. Both construction and management are answer to competitive port of Shanghai. Conclusions - From the development strategy of Shanghai port, hardware and software aspects should be emphasized, and it is evident that both trade volume of shipping market and the willingness of port authority have to be getting along with each other in development strategy.

• 한국항만학회지
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• 제13권2호
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• pp.351-364
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• 1999

This study aims at advancing waterfront planning and development of North Port or of Pusan and attempting to establish an identity through the analysis and case studied of waterfront development of foreign countries. This study is based on Pusan urban harbor plan and the case study which was investigated the relational port with an urban area to find a model of development method and procedure of urban waterfront renewal. The approach of this study is to classify diversified cases and to suggest elements after reviewing successful cases. The point in the waterfront development plan of North Port of Pusan is how to secure an amenity on the edge and provides a comprehensive theoretical base such as skyline, coastline, green area, accessibility scenery, landmark, open space, and so on. The results of this stud is useful for the planner to develop more and systematic approaches which could utilize waterfront. Waterfront development will be a new change of urban development for Pusan.