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Calibration of frequency propagation channel sounder based on five-port reflectometer

  • Yem Van;Braga Judson;Huyart B;Begaud X;de Sousa F.R;Huyen Nguyen Bich
    • Proceedings of the IEEK Conference
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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.

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Unified DC Offset Cancellation and I/Q Regeneration with Carrier Phase Recovery in Five-Port Junction based Direct Receivers (Five-port 접합을 이용한 RF 수신기를 위한 동시 DC 오프셋 제거와 I/Q 신호 재생 알고리즘)

  • Park, Hyung-Chul;Lim, Hyung-Sun;Yu, Jong-Won
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.6
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    • pp.64-70
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    • 2007
  • This paper presents a novel unified DC offset cancellation and I/Q regeneration for five-port junction based direct receivers. It utilizes the symmetry characteristics of the single-frequency continuous-wave (CW) signal, making it possible that the proposed method can be used regardless of carrier phase offset. The proposed method eliminates the additional DC offset cancellation and reduces the I/Q regeneration parameter estimation time. Since the proposed method employs a single-frequency CW signal independent of the modulation scheme, five-port junction based direct receivers can be used for the demodulation of orthogonal frequency-division multiplexing and continuous phase modulation as well as phase shift-keying.

Three-Port Laparoscopic Exploration is not Sufficient for Patients with T4 Gastric Cancer

  • Huang, Hua;Jin, Jie-Jie;Long, Zi-Wen;Wang, Wei;Cai, Hong;Liu, Xiao-Wen;Yu, Hong-Mei;Zhang, Li-Wen;Wang, Ya-Nong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.19
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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.

A study on the selection of management target fishing port for efficient management of fishing boats and pleasure boats - Jeju special self-governing province focuses on the fishing port - (어선과 레저선박의 효율적 관리를 위한 관리대상 어항 선정에 대한 연구 - 제주특별자치도 어항을 중심으로 -)

  • KIM, Keun-Hyoung;HEO, Nam-Hee;KIM, Suk-Jong
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.56 no.4
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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.

Single-Port Video-Assisted Thoracic Surgery for Secondary Spontaneous Pneumothorax: Preliminary Results

  • Kim, Min-Seok;Yang, Hee Chul;Bae, Mi-Kyung;Cho, Sukki;Kim, Kwhanmien;Jheon, Sanghoon
    • Journal of Chest Surgery
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    • v.48 no.6
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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.

A Study on the Performance Evaluation and Revitalization of Korea Port Distripark (항만배후단지 성과평가와 활성화 연구)

  • Kim, Seung-Chul;Kang, Hyo-Won
    • Journal of Korea Port Economic Association
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    • v.36 no.3
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    • pp.137-154
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    • 2020
  • In this study, we analyze the performance of five major port distriparks and present a development plan. The analysis groups the performance into three categories: revitalization of companies in port distriparks, contribution to the port volume, and contribution to the national economy. The key parameters examined in detail include the ratio of hinterland volume to port volume (container and total cargo), port volume growth contribution rate, and job creation. Our results indicate that Gwangyang and Ulsan Ports showed steady growth for all the indicators analyzed, while Gwangyang Port was the only one among the five ports to display consistent steady growth. The results suggest that to achieve consistent growth, high value-added and specialized port distriparks based on the local economy should be established.

A Study on Operation Efficiency of Container Port by Comparison of Similar Ports (동종 항만군 분류를 통한 컨테이너항만의 운영효율화 방안에 관한 연구)

  • 정태원;곽규석
    • Journal of Korean Society of Transportation
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    • v.19 no.1
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    • pp.7-16
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    • 2001
  • The Principle objective of this paper is to introduce a systematic approach to identifying similar container ports in Asia. For this, it analyses data on port facilities, port facility availability, port service level total container throughput, and economic index, by using Multidimentional Scaling (MDS) method. Based on the analysis it identifies five groupings of similar container ports in Asia within which Port comparison can be justifiably made, evaluates a present position of five groupings on the basis of factors used to compare container ports in Asia ; and finally proposes policy implications for operation efficiency of Pusan container port in comparison with Kaohsiung Port. The major implication is that both the Kaosuing and the Pusan port have to strengthen port facility to attract more traffic, and particularly, Pusan Port has to reinforce the number of berth, total length of berth. and yard areas.

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The Comparative Study on the Efficiency of Five Largest Seaports in Korea (한국 5대 항만의 효율성에 대한 비교연구)

  • Na, Ho-Su;Lee, U;Lee, Gyeong-Su
    • Journal of Korea Port Economic Association
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    • v.24 no.4
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    • pp.25-46
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    • 2008
  • By using data envelopment analysis(DEA) this research measures the efficiency of Korea's five seaports and their Malmquist productivity from 1997 to 2006. Under the assumption of CRS(constant returns to scale) and VRS(various returns to scale), seaports' rankings of efficiency are measured. Busan port is confirmed as a best-performed port in the various measurements. Important finding facts are as follows. 1)Busan, lncheon and Ulsan seaports are efficient ports under the assumption of CRS and VRS. 2)Gwangyang port shows 4.3% lower efficiency level compared with efficient ports. 3)Pohang port shows 27.3% lower efficiency level compared with efficient ports. 4)Average total factor productivity of Korea's five ports has been lower at the rate of 3.1% during the period from 1997 to 2006. Main policy implications are 1)Busan port is more efficient than Gwangyang port, which reflects the difference of economic activities between two regional econmies. 2)During the period 1997-2006, Korea's five largest ports has experienced lower efficiency levels in the first half period because of the 1997 Korean Financial Crisis, but higher efficiency levels in the second half period because of economic recovery. In future research the more and better data will be expected to improve the understanding of Korean seaports' efficiency characteristics.

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Performance Analysis of Improved Direct Conversion Six-port Phase Correlator (대역폭이 향상된 직접변환 Six-port 위상 상관기 성능분석)

  • Yu, Jae-Du;Kim, Young-Wan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.91-94
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    • 2007
  • In this paper, the six-port phase correlator using $90^{\circ}$ hybrid branch-line coupler and three-arm branch $90^{\circ}$ hybrid coupler were designed. The performances for two six-port phase correlators were analyzed by using ADS2003A tool. Three-arm six-port phase collerator provides more wide dynamic frequency range than that of six-port using the conventional hybrid coupler in range of circa five times. Six-port phase correlators were fabricated to evaluate the performance of two six-port phase correlators. The measured performances for two six-port phase correlators show the good accordance with the simulation data.

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Classification of International Container Ports by Using Principal Component Analysis and Cluster Analysis (주성분분석 및 군집분석을 이용한 컨테이너항만의 분류)

  • 문성혁;이준구
    • Journal of Korean Port Research
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    • v.13 no.1
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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.

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