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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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Design and Performance Analysis of Wideband Six-port Phase correlator (대역폭이 향상된 Six-port 위상 상관기 설계 및 성능 분석)

  • Kim, Young-Wan;Yu, Jae-Du
    • 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.

Decoupled Power Control of Three-port Dual Active Bridge DC-DC Converter for DC Microgrid Systems (DC 마이크로 그리드를 위한 Three-port Dual Active Bridge DC-DC 컨버터의 독립 전력 제어)

  • Sim, Ju-Young;Lee, Jun-Young;Choi, Hyun-Jun;Kim, Hak-Sun;Jung, Jee-Hoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.5
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    • pp.366-372
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    • 2018
  • Three-port dual-active bridge (DAB) converter in a DC microgrid was studied due to its high power density and cost-effectiveness. The other advantages of DAB include galvanic isolation and bidirectional power conversion capability using simple control modulation. The three-port DAB converter consists of a three winding transformer and three bridges. The transformer has three phases, which means that the ports are coupled. Thus, the three-port DAB converter causes unwanted power flows when the load connected to each port changes. The basic operational principles of the three-port DAB converter are presented in this study. The decoupling control strategy of the independent port power transfer is presented with a mathematical power model to overcome the unexpected power flow problem. The validity of the proposed analysis and control strategy is verified with PSIM simulation and experiments using a 1-kW prototype power converter.

Early Outcomes of Single-Port Video-Assisted Thoracic Surgery for Primary Spontaneous Pneumothorax

  • Kang, Do Kyun;Min, Ho Ki;Jun, Hee Jae;Hwang, Youn Ho;Kang, Min-Kyun
    • Journal of Chest Surgery
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    • v.47 no.4
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    • pp.384-388
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    • 2014
  • Background: Recently, single-port video-assisted thoracic surgery (VATS) has been proposed as an alternative to the conventional three-port VATS for primary spontaneous pneumothorax (PSP). The aim of this study is to evaluate the early outcomes of the single-port VATS for PSP. Methods: VATS was performed for PSP in 52 patients from March 2012 to March 2013. We reviewed the medical records of these 52 patients, retrospectively. Nineteen patients underwent the conventional three-port VATS (three-port group) and 33 patients underwent the single-port VATS (single-port group). Both groups were compared according to the operation time, number of wedge resections, amount of chest tube drainage during the first 24 hours after surgery, length of chest tube drainage, length of hospital stay, postoperative pain score, and postoperative paresthesia. Results: There was no difference in patient characteristics between the two groups. There was no difference in the number of wedge resections, operation time, or amount of drainage between the two groups. The mean lengths of chest tube drainage and hospital stay were shorter in the single-port group than in the three-port group. Further, there was less postoperative pain and paresthesia in the single-port group than in the three-port group. These differences were statistically significant. The mean size of the surgical wound was 2.10 cm (range, 1.6 to 3.0 cm) in the single-port group. Conclusion: Single-port VATS for PSP had many advantages in terms of the lengths of chest tube drainage and hospital stay, postoperative pain, and paresthesia. Single-port VATS is a feasible technique for PSP as an alternative to the conventional three-port VATS in well-selected patients.

A Study on Competitive Power Comparison and Strategy Collaboration of the Biggest Three Ports of the Economic Circle Around Bohai

  • Meng, Qing-Chun;Sun, Han-Gao
    • Proceedings of the Korea Port Economic Association Conference
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    • pp.441-455
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    • 2007
  • Based on the fact that Qingdao port, Tianjin port and Dalian port of the economic circle around Bohai have been the three islands of stability through long-term competition, this paper conducts a system study on the competitive powers of the three ports through AHP model on the analysis of current status of the three ports, and probes deeply into the outer factors and the inner factors affecting on the competitive advantage, and points out the existing problems in competition. We think that the three ports must compete orderly and collaborate closely, and give the forms and approaches developing strategy collaboration in order to obtain an advantageous position in Northeast Asia and improve the international competitive power.

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Three-Port Converters with a Flexible Power Flow for Integrating PV and Energy Storage into a DC Bus

  • Cheng, Tian;Lu, Dylan Dah-Chuan
    • Journal of Power Electronics
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    • v.17 no.6
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    • pp.1433-1444
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    • 2017
  • A family of non-isolated DC-DC three-port converters (TPCs) that allows for a more flexible power flow among a renewable energy source, an energy storage device and a current-reversible DC bus is introduced. Most of the reported non-isolated topologies in this area consider only a power consuming load. However, for applications such as hybrid-electric vehicle braking systems and DC microgrids, the load power generating capability should also be considered. The proposed three-port family consists of one unidirectional port and two bi-directional ports. Hence, they are well-suited for photovoltaic (PV)-battery-DC bus systems from the power flow viewpoint. Three-port converters are derived by combining different commonly known power converters in an integrated manner while considering the voltage polarity, voltage levels among the ports and the overall voltage conversion ratio. The derived converter topologies are able to allow for seven different modes of operation among the sources and load. A three-port converter which integrates a boost converter with a buck converter is used as a design example. Extensions of these topologies by combining the soft-switching technique with the proposed design example are also presented. Experiment results are given to verify the proposed three-port converter family and its analysis.

The Relative Effects of Three Dimensions of Service Quality of Ports in the Yellow Sea Region (환황해권 항만의 서비스 품질 각 차원이 고객만족에 미치는 상대적 영향에 관한 연구)

  • Kim, Byung-Il;Yu, Hong-Seong
    • Journal of Korea Port Economic Association
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    • v.23 no.4
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    • pp.1-22
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    • 2007
  • The present study examined the effects of the factors of port service quality on customer satisfaction and surveyed customers' perception on service quality and their satisfaction with port services by comparing Incheon Port with Qingdo Port, Tianjin Port and Dalian Port. According to the results, the quality of port services can be divided into three levels-inner quality, external environment quality and interaction quality, and except the external environment quality of the Dalian Port, the three levels of service quality were found to have significant effects on customer satisfaction. In addition, according to the results of comparing customers' perception on the three levels of service quality among the ports, the Incheon Port was inferior to the Qingdo Port, the Tianjin Port and the Dalian Port in inner quality, and to the Qingdo Port and the Tianjin Port in external environment quality, but superior to the Tianjin Port and the Dalian Port in interaction quality. However, customers' satisfaction with the Incheon Port was lower than that with the Qingdo Port and the Tianjin Port.

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A Study on the Profitability of Private Finance Initiative Ports Companies and the Use of Old Ports Rehabilitate-Project

  • Yang, HuckJun
    • Journal of Navigation and Port Research
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    • v.44 no.5
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    • pp.430-437
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    • 2020
  • This paper analyzes the profitability of the Private Finance Initiative(PFI) ports and proposes the application plans of the R-project(Rehabilitate project) for old ports to attract and activate private investment in the port industry. The R-project of old ports can reduce the government's financial budget and provide improved facilities for users more quickly than the public sector comparator. Before suggesting the R-project for old ports, the profitability of the currently operating 11 companies of the PFI ports are analyzed using the four ratios of profitability, and the results show that all the companies indicate low profitability, except for the top three companies. To apply the R-project, the three types of R-project ports are categorized as maintaining the function of the port, changing the function of the port, and mixing the function of the port. Additionally, three obstacles and improvement measures are suggested; attracting private business, legal issues, and administrative procedures. This study is conducive to the policy making for the port renewal and the activating PFI for the port industry.

An Analysis and Design of Three-Line Three Port Bandpass / Bandstop Filter (3선 3포트 대역통과/대역소거 필터의 해석과 설계)

  • Jang, Sang-Gun;Chin, Youn-Kang
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.5 no.2
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    • pp.39-45
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    • 1994
  • Analysis and design procedure for three-line three port bandpass / bandstop fliter consisting of three line microstrip structures is reported. The measured results for experimental three port structure is shown to be in good agreement with theoretical poedictions.

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Non-Isolated Unidirectional Three-Port Cuk-Cuk Converter for Fuel Cell/Solar PV Systems

  • Chandrasekar, Balaji;Chellammal, N.;Nallamothu, Bhargavi
    • Journal of Power Electronics
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    • v.19 no.5
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    • pp.1278-1288
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    • 2019
  • A DC-DC Non-Isolated Three-Port Cuk-Cuk (NI-TPCC) converter for interfacing renewable energy sources (RESs) such as Fuel Cell (FC) and Photovoltaic (PV) energy with a DC load is presented in this paper. It features single-stage power conversion from both of the input ports to the load port. The proposed NI-TPCC converter is designed based on the classical Cuk converter. The operational modes and power flow are analyzed in the continuous conduction mode (CCM), and the relationships among the port voltages are derived. Continuous currents in all three ports with less ripple enhance the performance of a fuel cell and its operating life. Furthermore, the output inductor is shared with both of the input ports, which reduces the number of active and passive components. The effectiveness of the designed NI-TPCC converter has been validated through simulation and experimental results.