• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.129-132
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• 1998

A bond graph modeling approach which is equivalent to a finite element method is formulated in the case of the piezoelectric thickness vibrator. This formulation suggests a new definition of the generalized displacements for a continuous system as well as the piezoelectric thickness vibrator. The newly defined coordinates are illustrated to be easily interpreted physically and easily used in analysis of the system performance. The bond graph model offers the primary advantage of physical realizability and has a greater physical accuracy because of the use of multiport energic elements. While results are presented is general in scope and can be applied to arbitrary physical systems.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.105-112
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• 2003

This paper presents the numerical design technology of a passive orifice fluid damper system especially for the characteristics between the damper piston velocity and the damping force. Numerical analysis with the visual interfacial modeling technique was applied into the analysis of the damper system's dynamics. A prototype orifice fluid damper was manufactured and experimentally tested to validate the numerical simulation results. The performances of various damper system schemes were investigated based on the verified numerical simulation model of orifice fluid damper.

• Journal of Veterinary Science
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• v.19 no.6
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• pp.862-864
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• 2018

An elective laparoscopic ovariectomy on a healthy dog revealed a cystic structure in the left ovary. The surgical procedure was successful. Histopathological examination showed the presence of a teratoma adjacent to the ovary. To the best of the authors' knowledge, this is the first reported case of an ovarian teratoma removed by laparoscopic ovariectomy in a dog by using a multiport laparoscopic ovariectomy technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.521-524
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• 2015

This letter presents a selective wireless power transfer architecture using a reconfigurable multi-port amplifier. The proposed wireless power transfer architecture is composed of a phase shifter part controlled by FPGA, two class-E power amplifiers, a four-port power combiner and two coil loads. Depending on the phase control of FPGA, the power ratio of outputs at the two coil loads becomes 1:1, 2:0 and 0:2. The manufactured system has delivered 1W DC power to loads at 125 kHz. The total DC-to-DC conversion efficiency shows more than 40 % including PA efficiency of 79 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.6
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• pp.637-645
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• 2014

This paper presents a new $4{\times}4$ multi-port amplifier(MPA) structure using reconfigurable switching matrices as input and output hybrid matrices(IHM, OHM), and phase/amplitude error calibration circuits. According to the mode selection of the switches, output power can be flexibly and effectively managed since the number of PA's to be used and the number of output port to distribute/combine amplified signals can be controlled. In addition, the proposed structure contains the phase and amplitude error calibration block that helps produce identical amplitudes and desired phase differences to the $4{\times}4$ OHM, resulting in optimizing the port-to-port isolation of the MPA system.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.5
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• pp.505-513
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• 2023

Hydrogen infrastructure is expanding. High-capacity hydrogen refueling stations offer advantages because they can refuel a variety of light and heavy-duty vehicles, and multi-port refueling technology is developing to reduce charging time for heavy-duty vehicles. In this study, we suggest directions to lower the risk by analyzing the risk factors for each process involved in the installation of a high-capacity multi-port hydrogen refueling station in Changwon city. We conducted both qualitative and quantitative risk assessments of the equipment to evaluate the station. A hazard and operability study was performed for qualitative risk assessment, and PHAST/SAFETI were used for quantitative risk assessment. Quantitative risk assessment was used to calculate the consequence analysis of the facility to ensure secure design prior to station development and to predict individual and societal risks in various scenarios. As a result, the station's risk level was determined to be as low as reasonably practicable.

• Journal of Yeungnam Medical Science
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• v.41 no.1
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• pp.48-52
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• 2024

While simultaneous bilateral partial nephrectomy with a conventional multiport robot has been consistently reported since the 2010s, the introduction of the DaVinci SP system (Intuitive Surgical, Sunnyvale, CA, USA) could provide a novel way to perform surgery on bilateral kidneys while innovatively reducing the number of incisions. In our first report worldwide, the patient with bilateral small renal mass (2.0 cm for the left and 1.5 cm for the right side) and preoperative normal renal function was placed in the lateral decubitus position on an inverted bed. After tilting the bed to be as horizontal as possible, a 4-cm incision was made in the lower part of the umbilicus for the floating trocar technique. The partial nephrectomy was performed reliably as with the conventional transperitoneal approach, and then the patient could be repositioned to the contralateral side for the same procedure, maintaining all trocars. Total operation time (skin to skin), total console time, and the left- and right-side warm ischemic times were 260, 164, 27, and 23 minutes, respectively, without applying the early declamping technique. The estimated blood loss was 200 mL. The serum creatinine right after the operation, on the first day, 3 days, and 90 days after surgery were 0.92, 0.77, 0.79, and 0.81 mg/dL, respectively. For 90 days after the procedure, no complications or radiologic recurrence were observed. Further clinical studies will reveal the advantages of using the DaVinci SP device for this procedure over traditional multiport surgery, maximizing the benefit of a single port-based approach.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.265-271
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• 1997

A bond graph modeling approach which is equivalent to a finite element method is formulated in the case of the piezoelectric thickness vibrator. This formulation suggests a new definition of the generalized displacements for a continuous system as well as the piezoelectric thickness vibrator. The newly defined coordinates are illustrated to be easily interpreted physically and easily used in analysis of the system performance. Compared to the Mason equivalent circuit model, the bond graph model offers the primary advantage of physical realizability. Compared to circuit models based on standard discrete electrical elements, the main advantage of the bond graph model is a greater physical accuracy because of the use of multiport energic elements. While results are presented here for the thickness vibrator, the modeling method presented is general in scope and can be applied to arbitrary physical systems.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.4
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• pp.196-203
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• 2001

본 논문에서는 빠른 시간 내에 설계자의 요구사양을 만족하는 메모리를 자동으로 합성해주는 새로운 멀티포트 메모리 컴파일러를 제안하였다. 제안한 컴파일러의 장점은 하나의 메모리 코어 셀을 규칙적으로 배치, 확장하여 메모리를 합성하고, 동시에 합성된 메모리내의 임계경로만을 추출하여 빠르게 검증할 수 있다는 것이다. 또한, 레이아웃 상에서의 전원선 공유 등의 기법으로 메모리의 성능을 향상시킬 수 있도록 하였다. 본 컴파일러를 사용하여 0.25$\mu\textrm{m}$ CMOS 1-poly, 2-metal 공정에서 최대 8개의 쓰기 포트, 16개의 읽기 포트, 64워드, 256비트 사이의 여러 가지 멀티포트 메모리를 자동 합성하였다. 합성 결과 메모리의 성능 및 면적 면에서 만족할 만한 결과를 얻었으며, 레이아웃 전체에서의 시뮬레이션 시간보다 10배정도 빠른 시간 내에 동작을 정확히 검증하였다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.594-596
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• 1996

Static power converters can be analyzed by means of available circuit simulation software packages such as PSPICE. This paper proposes the macro models developing technique for three-phase power converters using the transfer function approach. Also, these models are based on converter switching functions rather than actual circuit configuration. In this approach, VSI(Voltage Source Inverter) and CSI(Current Source Inverter) are simulated as multiport networks avoiding nonlinear macromodels of the power switches.