• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1680-1683
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• 2003

To describe the performance of an antenna, some parameters are necessary. Some of the parameters are interrelate and not all of them must be specified for complete description of antenna performance. The parameters in characteristics of printed antenna for this analysis are radiation pattern, input impedance, VSWR, S parameter and electromagnetic field. In this paper we will consider two shaped of slot antennas one is triangular slot antenna and other is L - shape slot antenna for compare the radiation pattern, return loss, and VSWR. Two slot antennas are designed to have a resonant frequency at 10 GHz. The microstrip line is designed to be 50 ohms in order to match the measurement system, it has the substrate of the thickness = 1.52 mm and dielectric constant (${\varepsilon}_r$) 2.17. The problem space in the FDTD analysis are $60{\times}123{\times}100$ cells for L-shape slot antenna and $50{\times}171{\times}120$ cells for triangular slot antenna with the cell dimensions ${\Delta}x=0.152\;mm.$, ${\Delta}y={\Delta}z=0.15\;mm.$

• 방사성폐기물학회지
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• 제18권spc호
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• pp.63-74
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• 2020

The operational safety assessment is an important part of a safety case for the deep geological repository of spent fuels. It consists of different stages such as the identification of initiating events, event tree analysis, fault tree analysis, and evaluation of exposure doses to the public and radiation workers. This study develops a probabilistic safety assessment method for the operational safety assessment and establishes an assessment framework. For the event and fault tree analyses, we propose the advanced information management system for probabilistic safety assessment (AIMS-PSA Manager). In addition, we propose the Radiological Safety Analysis Computer (RSAC) program to evaluate exposure doses to the public and radiation workers. Furthermore, we check the applicability of the assessment framework with respect to drop accidents of a spent fuel assembly arising out of crane failure, at the surface facility of the KRS⁺ (KAERI Reference disposal System for SNFs). The methods and tools established through this study can be used for the development of a safety case for the KRS⁺ system as well as for the design modification and the operational safety assessment of the KRS⁺ system.

• 대한방사선기술학회지:방사선기술과학
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• 제39권1호
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• pp.13-17
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• 2016

모든 의료방사선 검사는 정당성과 최적화가 확보되어야 한다. 특히 질병의 예방과 조기 진단을 목적으로 하는 건강검진에서 방사선 피폭의 최적화를 위한 모니터링은 절대적으로 필요하다. 본 연구에서는 DICOM 규격을 이용하여 건강검진센터의 의료방사선 피폭 품질관리 사례에 대해 보고하고자 한다. 적용된 시스템을 이용하여 건강검진센터의 진단참고 값을 제정하고 이를 통한 품질관리를 시행하였다. CT에서는 전체 703명에 대한 진단참고 값으로 복부검사에서 $357.9mGy{\cdot}cm$, 두부검사에서 $572.38mGy{\cdot}cm$, 심장혈관 칼슘검사에서 $55.92mGy{\cdot}cm$, 저선량 폐 검사에서 $53.98mGy{\cdot}cm$, 경추 검사에서 $284.99mGy{\cdot}cm$, 요추 검사에서 $341.85mGy{\cdot}cm$를 도출 하였으며, 흉부 X선 검사 1955건에 대해 $274.0mGy{\cdot}cm$2과 유방 촬영에서는 6.09 mGy의 진단참고 값를 도출하였다. 본 연구에서 개발된 시스템은 건강검진센터에서 수검자에 조사되는 방사선의 피폭선량을 실시간으로 모니터링하고 이를 이용한 피폭선량의 최적화와 정당화를 위한 품질관리 도구로 활용될 것이다.

• 한국전자파학회논문지
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• 제23권10호
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• pp.1204-1211
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• 2012

본 연구에서는 위성 SAR(Synthetic Aperture Radar) 시스템 검 보정을 위한 기반기술 습득을 위해 수행된 X-밴드 대역 능동전파반사기를 이용한 실제 위성 SAR 방사 패턴 측정 및 분석에 관한 연구 결과를 선보인다. 실험에 사용된 자체 설계/제작된 능동전파반사기는 최대 63.1 dBsm의 레이더 단면적(RCS: Radar Cross Section)을 가지며, 외부 수신 장치를 이용한 수신 기능을 포함한다. 위성 SAR 시스템의 방사 패턴 측정 정확도를 높이기 위해 동일한 운용 모드의 위성 SAR(COSMO-SkyMed 2/3호, hh-편파, strip-map himage mode, 해상도 3 m) 시스템을 이용하였으며, 이때, SAR 영상 데이터 내 능동전파반사기의 RCS 크기 분석을 병행하여 측정 결과의 신뢰도를 교차분석하였다. 수신된 신호로부터 추출된 위성 SAR 시스템의 방위각 방향 방사 패턴 특성은 각각 HPBW(half-power beamwidth) $0.352^{\circ}$, FNBW(first-null beamwidth) $0.691^{\circ}$, PSLR(peak to side lobe ratio) 11.17 dB이다.

• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.22-27
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• 2010

In photovoltaic system, the specifications of solar array is changed as open circuit voltage and short circuit current because of cell temperature and solar radiation. A boost converter of this system connects between output of photovoltaic system and DC link capacitor of grid connected inverter as controlling duty ratio. Therefore to supply stable voltage to the grid, a boost converter is need to keep certain voltage output. Considering the capacitance and the resistance of boost converter, this paper designed proper digital controller.

• 정보통신설비학회논문지
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• 제11권2호
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• pp.39-45
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• 2012

In recent years the USN(Ubiquitous Sensor Networks) technology has been applied in the greenhouse in order to control temperature and humidity automatically. In this paper, we proposed a control algorithm using feedback linearization techniques based on a mathematical model for temperature and humidity environment. Especially, Control algorithm is presented to the operation of the ventilator affecting on the temperature and humidity system at the same time. The System has been designed taking into account the disturbance(External temperature, soil temperature, external humidity, solar radiation and wind). In conclusion, I will present a way to control multiple actuator through simulations. The proposed control algorithm is validated using the Matlab/Simulink tools.

• Journal of the Korean Physical Society
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• 제73권10호
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• pp.1420-1430
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• 2018

We investigate an entangled system, which is analogous to a composite system of a black hole and Hawking radiation. If Hawking radiation is well approximated by an outgoing particle generated from pair creation around the black hole, such a pair creation increases the total number of states. There should be a unitary mechanism to reduce the number of states inside the horizon for black hole evaporation. Because the infalling antiparticle has negative energy, as long as the infalling antiparticle finds its partner such that the two particles form a separable state, one can trace out such a zero energy system by maintaining unitarity. In this paper, based on some toy model calculations, we show that such a unitary tracing-out process is only possible before the Page time while it is impossible after the Page time. Hence, after the Page time, if we assume that the process is unitary and the Hawking pair forms a separable state, the internal number of states will monotonically increase, which is supported by the Almheiri-Marolf-Polchinski-Sully (AMPS) argument. In addition, the Hawking particles cannot generate randomness of the entire system; hence, the entanglement entropy cannot reach its maximum. Based on these results, we modify the correct form of the Page curve for the remnant picture. The most important conclusion is this: if we assume unitarity, semi-classical quantum field theory, and general relativity, then the black hole should violate the Bekenstein-Hawking entropy bound around the Page time at the latest; hence, the infinite production arguments for remnants might be applied for semi-classical black holes, which seems very problematic.

• 전력전자학회논문지
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• 제26권1호
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• pp.38-45
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• 2021

The photovoltaic module has the characteristic of changing its output characteristics depending on the amount of radiation and temperature, where the arrays that connect them in series and parallel also have the same characteristics. These characteristics require the MPPT technique to find the maximum power point. Existing P&O and IncCond cannot find the global maximum power point (GMPP) for partial shading. Moreover, in the case of Improved-GMPPT and Enhanced Search-Skip-Judge-GMPPT, GMPP due to partial shading can be found, but the variation in the open voltage during temperature fluctuations will affect the operation of the Skip and will not be able to perform accurate MPPT operation. In this study, we analyzed the correlation between voltage, current, and power under solar module and array conditions. We also proposed a technique to find the maximum power point even for temperature fluctuations using not only the amount of radiation but also the temperature coefficient. The proposed control technique was verified through simulations and experiments by constructing a 2.5 kW single-phase solar power generation system.

• International Journal of Computer Science & Network Security
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• 제24권4호
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• pp.87-106
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• 2024

Vehicle-to-Home (V2H) and Home Centralized Photovoltaic (HCPV) systems can address various energy storage issues and enhance demand response programs. Renewable energy, such as solar energy and wind turbines, address the energy gap. However, no energy management system is currently available to regulate the uncertainty of renewable energy sources, electric vehicles, and appliance consumption within a smart microgrid. Therefore, this study investigated the impact of solar photovoltaic (PV) panels, electric vehicles, and Micro-Grid (MG) storage on maximum solar radiation hours. Several Deep Learning (DL) algorithms were applied to account for the uncertainty. Moreover, a Reinforcement Learning HCPV (RL-HCPV) algorithm was created for efficient real-time energy scheduling decisions. The proposed algorithm managed the energy demand between PV solar energy generation and vehicle energy storage. RL-HCPV was modeled according to several constraints to meet household electricity demands in sunny and cloudy weather. Simulations demonstrated how the proposed RL-HCPV system could efficiently handle the demand response and how V2H can help to smooth the appliance load profile and reduce power consumption costs with sustainable power generation. The results demonstrated the advantages of utilizing RL and V2H as potential storage technology for smart buildings.

• 한국방사선학회논문지
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• 제6권2호
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• pp.143-149
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• 2012

오늘날 의료영상매체의 획기적인 발전으로 각 병원에서 최신 의료장비를 도입함으로써 첨단화, 디지털화로 급변하는 추세이다. 이러한 움직임에 발맞추어 방사선 종양학과에서도 CR system을 도입하여 film system의 단점을 보완하고 병원에서 사용하고 있는 Picture Archiving and Communication System(PACS)과 Electronic Medical Record (EMR) , 그리고 Radiation therapy Treatment Planning system(RTP)의 network를 원활히 하여 업무효율 증대 및 환자에 대한 의료의 질 개선과 서비스 향상을 이루고자 하고 있는데, 방사선 종양학과의 Computed Radiography system(CR system)을 이용하여 PACS에 통합한 사례를 소개하고 그 유용성을 평가하고자 한다. 의료용 선형가속기인 MEVATRON-MX를 이용하여 현재 시행하고 있는 정도관리 중 Gantry, Collimator Star Shot, Light vs. Radiation Field Accuracy, HDR QA(Dwell position accuracy)를 시행하여 PACS 상에 구현하였고 모니터 상에서 디지털 영상을 통한 QA가 가능한지 확인하였다. 또한, 현재 S병원에서 사용 중인 Operation Control System(OCS)과 연동하여 치료에 필요한 코드를 각각의 치료에 부과하여 네트워크로 연결, CR상에 입력한 order가 나타나도록 하였으며, Planning System인 Pinacle과 PACS상의 지원 data 오류를 해결하여 PACS 상에서도 Planning 영상을 볼 수 있도록 하였다. CR system을 이용하여 L-gram, simulation image, planning image를 병원 내 어느 곳에서나 영상을 조회하고 볼 수 있게 PACS에 통합 구축되어있다. Filmless 환경에서 Dosimetry용 IP를 이용하여 Light/Radition field size 일치, gantry rotation axis의 정확성, collimator rotation axis의 정확성, brachy therapy의 Dwell position check등 QA의 시행이 가능하였다. CR system을 이용하여 방사선 종양학과에서 얻어지는 영상을 PACS에 통합함으로써 작업시간 단축과 그에 따른 불필요한 인력소모의 감소 등으로 인하여 업무효율이 증대되었지만 향후 환자정보에 대한 보안을 필요로 한다.