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유형석 ( Yoo Hyoungsuk ),이동현 ( Lee Donghyun ) 농협대학교 협동조합경영연구소 2021 협동조합경영연구 Vol.55 No.-
These days, rural communities are characterized by chronic problems such as aging, local extinction, low farm income and lack of social overhead capital. Supporting a return to farming and the re-population of rural areas has been consistently cited as a solution to these problems. 2021 is expected to be an important time to promote the return to farming and rural areas due to the establishment of a second comprehensive plan to support farming and rural areas and the change in perception of agriculture. In response, this study summarizes the current status and actual conditions of major policies and the purpose of presenting measures to revitalize the return to farming and rural areas. In addition, the factors and cases of the failure to return to farming and rural areas were divided into farming and non-farming sectors and a policy on revitalizing farming and rural return is presented. The roles for revitalizing the return to farming and rural areas were organized into actual implementation stages (preparation, settlement, and growth) according to the implementation entity (central government, local government, and Nonghyup). However, this relies on the organic cooperation of the three entities. If the central government lays the foundation for a large-scale policy and local governments and Nonghyup play their respective roles, it is expected to support those returning to farming and rural living.
3 T 자기공명영상시스템에서의 마이크로스트립을 이용한 다양한 RF 공진기
유형석(Hyoungsuk Yoo) 대한전기학회 2013 전기학회논문지 Vol.62 No.5
This paper demonstrates four different radio frequency (RF) resonators at 3 T magnetic resonance imaging (MRI) system. An approach based on microstrip transmission line to identical RF resonators except upper stripline structure is investigated. Electromagnetic simulation results are compared for RF resonators and discussed in detail at 3 T.
유형석(Hyoungsuk Yoo) 대한전기학회 2016 전기학회논문지 Vol.65 No.1
This paper demonstrates a scalp-implantable miniaturized antenna at the medical implant communication service (MICS) (402–405MHz) band. The antenna size is only 27.63 mm3(8.5 mm × 6.5 mm × 0.5 mm), which is the smallest antenna for the MICS band. Miniaturization is achieved by using a symmetrical serpentine shaped radiating patch and placing open-end slots in the ground plane. In addition, co-axial feeding is used for excitation with a shorting pin connected between the radiator and ground. The antenna was simulated in a homogeneous skin model and in the human scalp. An experimental prototype of the proposed antenna was fabricated and measured in a skin-mimicking gel. Good agreement was obtained between the measurement and simulation results, showing a broad bandwidth of 49 MHz (from 395 to 444 MHz) for |S11| less than –10 dB and a maximum gain of -42.87 dBi. This gain is higher than the previous MICS antenna with respect to antenna size.
다채널 3T 자기공명장치에서의 Compressed B1 제어법
유형석(Hyoungsuk Yoo) 대한전기학회 2013 전기학회논문지 Vol.62 No.8
Our objective of this study was to reduce radio frequency coil (RF) control time at 3 T MRI systems. A compressed method is proposed with a convex optimization and pseudo-inverse method in multi-channel RF coils. After applying the proposed methods, fields are homogenized with less field data. Even with 80% compression, the fields are well homogenized and localized, indicating that mapping requires only 20% of the original data. Detailed values are compared between each compressed result in and outside the region of interest at 3 T.
자기공명영상시스템에서의 의료용 리드선의 전자기적 호환 연구
유형석(Hyoungsuk Yoo) 대한전기학회 2016 전기학회논문지 Vol.65 No.12
In the presence of an electrically conducting medical lead, radio frequency (RF) coils in magnetic resonance imaging (MRI) systems may concentrate the RF energy and cause tissue heating near the lead. A novel design for a medical lead to reduce this heating by introducing pins in the lead is presented. Peak 10 g specific absorption rate (SAR) in heart tissue, an indicator of heating, was calculated and compared for both conventional (Medtronic) lead design and our proposed design. Remcom XFdtd software was used to calculate the peak SAR distribution in a realistic model of the human body. The model contained a medical lead that was exposed to RF magnetic fields at 64 ㎒ (1.5 T), 128 ㎒ (3 T) and 300 ㎒ (7 T) using a model of an MR birdcage body coil. The proposed design of adding pins to the medical lead can significantly reduce the heating from different MRI systems.
유형석(Hyoungsuk Yoo) 대한전기학회 2017 전기학회논문지 Vol.66 No.6
In this study, a novel wideband conformal thin antenna is presented for endoscopic capsule application at the 915 MHz Industrial, Scientific and Medical (ISM) band. The thickness of the antenna is only 0.2 mm which can be wrapped inside a capsule’s inner wall. By cutting meandered slots on patch, open end slots on ground and utilizing long arm, the proposed antenna can obtain significant size reduction. The net volume of the proposed antenna including substrate and superstrate is only 37.4 mm<SUP>3</SUP> (187mm2 surface area). This conformal antenna has shown good performance through simulation and measurement with maximum gain of -23 dBi and wide bandwidth from 137 MHz - 205 MHz depending on different environment. In addition, the effect of internal materials specially metallic battery is discussed briefly.
유형석(Hyoungsuk Yoo) 대한전기학회 2017 전기학회논문지 Vol.66 No.2
In this study, we introduce a triple-band flexible implantable antenna that is tuned by using a ground slot in three specific bands, namely Medical Implanted Communication Service (MICS: 402-405 ㎒) for telemetry, the midfield band (lower gigahertz: 1.45-1.6 ㎓) for Wireless Power Transfer (WPT), and the Industrial, Scientific and Medical band (ISM: 2.4-2.45 ㎓) for power conservation. This antenna is wrapped inside a printed 3D capsule prototype to show its applicability in different implantable or ingestible devices. The telemetry performance of the proposed antenna was simulated and measured by using a porcine heart. From the simulation and measurement, we found that use of a ground slot in the implantable antenna can improve the antenna performance and can also reduce the Specific Absorption Rate (SAR).
유형석(Hyoungsuk Yoo) 대한전기학회 2013 전기학회논문지 Vol.62 No.9
Plane wave scattering from a spherical resonator is calculated by solving the combined field integral equation (CFIE) with Rao-Wilton-Glisson (RWG) basis functions and the moment method. The calculations show that magnetic and electric dipoles are found at resonant modes. These characteristics are confirmed by radiation patterns in the far field region. In addition, an analysis of a magnetodielectric sphere is discussed.