• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.23-26
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• 2004

Five-port reflectometer which consists of a ring with 5 arms (two inputs, three outputs) and three RF power detectors has been used as a vector network analyser, a demodulator in the homodyne receiver as well as in Phase Looked Loop (PLL) and so on. Calibration of five-port reflectometer is an important task. In this paper, we present a calibration method of five-port for a propagation channel sounder. The method is based on measurement of the phase differences between the three voltages at the five-port's outputs in order to determine the ratio of two input incident waves. The frequency channel sounder based on five-port is calibrated for each frequency from 2.2 GHz to 2.6 GHz with 1 MHz step. This method can also determine the absolute delays of each propagation path in the propagation channel. The calibration method is validated using measurement data.

• 대한전자공학회논문지TC
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• 제44권6호
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• pp.64-70
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• 2007

본 논문에서는 five-port 접합을 이용한 RF 수신기를 위한 새로운 동시 DC 오프셋 제거와 I/Q 신호 재생 알고리즘을 제안한다. 제안한 방법에서는 단일주파수 CW 신호를 사용하는데, 제안한 방법이 반송파 위상 오프셋에 상관없이 사용할 수 있도록 한다. 또한 제안한 방법은 추가적인 DC 오프셋 제거 기능이 필요 없고, I/Q 재생 파라미터 추정시간을 크게 줄인다. 제안한 방법에서는 변조방식에 상관이 없는 단일주파수 CW 신호를 사용하므로, five-port 접합을 이용한 RF 수신기가 위상편이변조 (PSK) 뿐 만 아니라, 연속위상변조 (CPM)와 직교주파수다중분할 (OFDM)에도 사용될 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8221-8224
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• 2014

Gastric cancer continues to be a leading cause of cancer death. The majority of patients with gastric adenocarcinoma in China present with advanced disease. Ruling out unresectable cancers from an unnecessary "open" exploration is very important. The aim of this study was to assess the value of five-port anatomical laparoscopic exploration in T4 gastric cancer in comparison with three-port laparoscopic exploration and laparotomy exploration. We conducted a retrospective study on 126 patients with T4 stage scheduled for D2 curative gastrectomy based on computed tomography (CT) staging at Department of Gastric Cancer and Soft Tissue Sarcoma, Fudan University Shanghai Cancer Center, from Apr. 2011 to Apr. 2013. Laparotomy exploration (Group I), three-port laparoscopic exploration (Group II) or five-port anatomical laparoscopic exploration (Group III) were performed prior to radical gastrectomy. Accuracy rate for feasibility of D2 curative gastrectomy in laparotomy exploration and five-port anatomical laparoscopic exploration groups was higher than that in the three-port laparoscopic exploration group. Five-port anatomical laparoscopic exploration group had the highest accuracy resection rate (Group I vs Group II vs Group III,92.6% vs78.6% vs 97.7%; p<0.05) and shorter length of hospitalization (Group I vs Group II vs Group III, $9.58{\pm}4.17$ vs $6.13{\pm}2.85$ vs $5.00{\pm}1.81$; p<0.001). Three-port laparoscopic exploration has low accuracy rate for assessing feasibility of D2 curative gastrectomy and five-port anatomical laparoscopic exploration should be performed on patients with T4 gastric cancer.

• Journal of Korea Trade
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• 제25권5호
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• pp.58-73
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• 2021

Purpose - In the context of economic globalization and the continuous development of international trade, as countries around the sea peninsula, port construction is particularly important. Based on the research on the influencing factors of port logistics development based on the allocation analysis, QCA (Qualitative Comparative Analysis) provides the basis for the planning and policy of port logistics development and has important theoretical value and practical significance for improving the level of port logistics management, reducing logistics operating costs and increasing economic benefits. In the tide of global integration for the development of port logistics, promote the growth of foreign trade economy of the city. It is also of great significance to the development and progress of commerce and trade. Design/methodology - Based on the relevant data samples of various ports in South Korea, this paper uses fsQCA (fuzzy set Qualitative Comparative Analysis) to integrate and analyze the influence mechanism of port logistics development and extracts five influencing factors of port logistics development, including the port's scale and infrastructure in the hard environment, port-neighboring enterprises in the soft environment, hinterland economy and government support. Findings - The five factors are unable to separately constitute the necessary and sufficient conditions of port logistics development, only a combined model can influence lake port logistics development. The scale and infrastructure of the port itself and port-neighboring ring enterprises are the main core conditions, which work together on the port, affect the throughput capacity of the port, and promote the development of port logistics. When the port-neighboring enterprises are not complete and the scale is low, the growth of port throughput will be restrained and the development of port logistics will be affected, whether the hinterland economic benefits are general, the development of port-neighboring enterprises is insufficient, or the government supports are limited. Originality/value - Through the research on the development of port logistics in South Korea from the perspective of configuration, this paper finds the configuration influence of hard environment and soft environment on the development of port logistics, which has important theoretical and practical significance for better promoting the development of port logistics in South Korea.

• 한국항만학회지
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• 제13권1호
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• pp.11-26
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• 1999

The subject of port efficiency is one of the important issues facing port authorities and policy makers today. A number of studies have been undertaken which compare ports in terms of their efficiency. But any port comparison can only be valid and meaningful if a port’s efficiency is compared with a similar port. The main objective of this paper is to introduce a systematic approach to identifying similar ports based on the technique of principal component analysis and cluster analysis. And it seeks to identify the most important factors underlying the port classification. Lack of awareness of which factors differentiate ports has resulted in an unnecessary collection of data which are of limited use in port classification. This paper has identified five groupings of similar ports within which port comparision can be justifiably made. This approach can be used for any future port comparision.

• 수산해양기술연구
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• 제56권4호
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• pp.361-373
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• 2020

In Jeju, in order to efficiently manage and coexist fishing boats and passenger ships in narrow ports, it is necessary to establish reasonable policies. The survey was conducted on 99 fishing ports, from December 1 to 31, 2018. A site survey was conducted on 30 parties (15 in Jeju City and 15 in Seogwipo City) concerning with the use of fishing ports in Jeju to review the appropriate conditions for selecting fishing ports as control subjects. The survey determined size of pleasure craft mooring within fishing port (20%), size of fishing boat mooring (20%), and accessibility of fishing port (20%) under on-site survey factors as well as willingness to form a consultative group between fishing boat and pleasure craft users (20%). Upon the request of the survey, positive and negative opinions were collected on the establishment of a safety control center in the fish port. Based on the survey results, the factors mentioned above were applied to each and every fishing port within Jeju. The bottom five fishing ports in Jeju with the lowest total factor scores were identified and selected as control subjects for review and study. Of the five fishing ports selected as control subjects amidst the 99 fishing ports in Jeju, Dodu Fishing Port had the lowest score of 22% among the national fishing harbors. Among the local fishing ports, Hwabuk Fishing Port had the lowest score of 18%, followed by Sagae Fishing Port with a score of 22%. Hamdeok Fishing Port had the lowest score of 24% among the fishing port villages, whereas Ojo Fishing Port had the lowest score of 24% among the small fishing ports.

• Journal of Chest Surgery
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• 제48권6호
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• pp.387-392
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• 2015

Background: The aim of this study was to evaluate the feasibility of single-port video-assisted thoracic surgery (VATS) in the treatment of secondary spontaneous pneumothorax (SSP). Methods: Twenty-four patients who were scheduled to undergo single-port VATS for SSP were studied. The medical records of the patients were retrospectively reviewed. The mean follow-up duration was $26.1{\pm}19.8$ months. In order to evaluate the feasibility of single-port VATS for SSP, the postoperative results of single-port VATS (n=15) in patients with emphysema were compared with those of emphysematous patients who underwent three-port VATS (n=15) during the study period. Results: Single-port VATS was feasible in 19 of 24 patients (79.2%), while an additional port was needed in five patients. In the single-port VATS patients, the median operation time, duration of chest tube drainage, and hospital stay were 84.0 minutes, one day, and two days, respectively. Postoperative complications included prolonged chest tube drainage for more than five days (n=1), wound infection (n=1), and vocal fold palsy (n=1). No recurrence of pneumothorax was observed during the follow-up period. The median operation time, duration of chest tube drainage, and hospital stay of the emphysematous patients who underwent single-port VATS were shorter than those who underwent three-port VATS group (p<0.05 for all parameters). Conclusion: Single-port VATS proved to be a feasible procedure in the treatment of patients with secondary spontaneous pneumothorax.

• 한국항만경제학회지
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• 제36권3호
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• pp.137-154
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• 2020

본 연구에서는 우리나라 주요 5개 항만배후단지의 성과를 분석하고 발전방안을 제시하고자 하였다. 성과분석은 단순한 물동량이나 입주기업의 유치수에서 벗어나 항만배후단지 입주기업 활성화, 항만물동량 기여, 국가경제기여 등 3개로 성과를 분류하고 세부적으로 입주기업 물동량 생산성, 총항만물동량 대비 항만배후단지 물동량 비율(컨테이너 화물, 총화물), 항만물동량 성장 기여율, 항만물동량 성장기여도, 물동량 부가가치 발생액, 일자리 창출 등 7개로 세분화하여 분석하였다. 모든 지표에서 있어 꾸준한 성장세를 보이고 있는 곳은 광양항, 울산항으로 나타났으며 광양항의 경우 5개 항만 중 가장 꾸준한 증가세를 보이고 있는 유일한 항만으로 분석되었다. 분석결과를 항만배후단지의 지속적인 성장을 위해 고부가가치 창출 배후단지 및 지역경제 기반한 특성화 배후단지 구축을 제안하였다.

• 대한교통학회지
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• 제19권1호
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• pp.7-16
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• 2001

본 연구는 경쟁상태에 있는 아시아 14개의 컨테이너 터미널을 항만시설 관련자료(시설, 시설가용성), 경제·사회 지표(인구, 1인당GNP), 항만서비스 관련자료(취항선사수), 그리고 컨테이너처리물동량 등에 의해 5개 항만군으로 분류한다. 분석방법으로는 평가자료가 실제 입력자료를 얼마나 잘 재현해 주는가를 나타내는 기준치인 스트레스값을 제시해 줌으로써 분석의 결과에 대한 적합도(Goodness of Fit)를 알 수 있는 다차원척도법을 이용한다. 5개 동종항만군의 분류를 통하여 부산항을 포함하여 아시아 각 항만들의 현 위치를 보다 세부적으로 파악할 수 있었으며, 동종항만으로 분류된 카오슝 항만과의 벤치마킹을 통해 부산항의 운영 효율성 증대를 위한 시사점을 제시하였다. 동종항만군의 분류 결과 카오슝 및 부산항만군은 다른 지표에 비해 항만기반시설이 부족한 것으로 분석되었다. 앞으로 이 항만군은 시설부문에 지속적인 투자가 이루어져야 할 필요가 있는 것으로 나타났다. 특히 부산항은 낮은 생산성의 원인을 밝혀 해결책을 모색하고. 항만기반시설 중 선석수, 안벽길이, 야드 공간 등을 확장하는 데 투자할 필요가 있는 것으로 나타났다.

• 한국항만경제학회지
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• 제24권4호
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• pp.25-46
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• 2008

이 연구는 DEA방식을 사용하여 1997년부터 2006년의 기간에 대하여 한국의 5대 항만의 효율성을 측정하고 아울러 맘퀴스트 생산성지수를 측정하고 비교한다. 규모에 대한 수익불변(CRS)과 규모에 대한 수익가변(VRS)을 가정하여 항만의 효율성수준을 측정한다. 부산이 가장 효율성이 높은 항만으로 측정되었다. 발견된 내용은 다음과 같다. 1)부산항, 인천항, 울산항은 CRS와 VRS에서 효율적인 항만으로 나타났다. 2)광양항은 효율적인 항만에 비하여 4.3%정도 낮은 효율성을 보여 주었다. 3)포항항은 효율적인 항만에 비해 27.3% 낮은 효율성을 보여 주었다. 4)한국의 5대 항만의 총요소생산성은 1997년에서 2006년 사이에 매년 3.1%정도씩 낮아졌다. 몇 가지의 정책함의는 다음과 같다. 1)부산항이 광양항보다 효율적으로 나타났는데 이는 두 지역경제의 경제활동의 차이를 반영하는 것으로 보인다. 2)1997년에서 2007년 사이에 한국의 5대 항만은 전반부의 기간에는 1997년의 한국의 금융위기로 인하여 낮은 효율성 수준을 보여주었으나, 후반부의 기간에는 경제회복으로 더 높은 효율성을 시현하였다. 미래의 연구에서는 더 풍부하고 신뢰성 있는 자료를 활용하여 한국의 항만의 특징을 더 잘 이해하도록 다양한 접근방법이 적용되기를 기대한다.