• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.69-72
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• 2009

In this paper, the Stand-alone underground water pumping system was developed that is consist of Submersible Pump (AC type), Photovoltaic Array and Power converter by the application of solar energy. And also wish to introduce system that is possible to supply of drinking water or water for agriculture using solar energy at desertification area or a Off-grid area, interior etc. and operation test results. This system can use in deep tube well of 200m range with common Submersible Pump and maximized to the quantity of pumping through M.P.P.T control. Also system availability raised through apply various driving mode.

• 정보통신설비학회논문지
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• 제10권1호
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• pp.33-39
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• 2011

This paper considers a performance analysis of set-top box (STB) power saving schemes. STB converts the signal into content which is then displayed on the television (TV) screen, and there are typically two operation modes: on mode and stand-by mode. The total energy consumption (TEC), a typical measure of power consumption of STB, is defined by the sum of power consumption in each mode. Recently there are some works of STB power saving schemes that transit STB operation modes efficiently, and the mode transition time point of those schemes can be different. Thus it is required to develop a performance evaluation method that reflects mode transition time points of each scheme to get TEC correctly. This paper proposes a performance evaluation method for STB power consumption using Poisson process to consider the mode transition time point. By modeling STB mode transitions as events of Poisson process, the average time duration of STB mode is computed and accordingly the effect of power saving is evaluated. The performance evaluation result shows that the proposed method achieves 1 to 19% improvement in power consumption compared with a conventional performance evaluation method.

• 항공우주시스템공학회지
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• 제9권1호
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• pp.12-18
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• 2015

The inter-conversion between different control laws in flight has a lot of risk. The SWM(Switching Mechanism) including logic and stand-by mode is designed to analyze the transient response of aircraft during inter-conversion between different control laws, based on the in-house software for non-real-time and real-time simulation. The SWM applies the fader logic of TFS(Transient Free Switch) to minimize the transient response of an aircraft during the inter-conversion, and applies the reset '0' type of the stand-by mode to prevent surface saturation due to integrator effect in the disengaged flight control law. The transition time is also important to minimize the objectionable transient response in the inter-conversion, as well as the transition control law design. This paper addresses the results of non-real-time simulation for the characteristics of transient response to different transition time to select the adequate transient time, and the real-time pilot evaluation, using SSWM(Software Switching Mechanism) and HSWM(Hardware Switching Mechanism), which is met for Level 1 flying qualities and assures safety of flight.

• Journal of electromagnetic engineering and science
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• 제17권1호
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• pp.29-33
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• 2017

This paper proposes a half-mode substrate integrated waveguide (HMSIW) amplifier using lumped-element transition. The input and output impedances of this amplifier are matched by the lumped-element transition structure. This structure provides compact impedance and mode matching circuits between the HMSIW and a stand-alone amplifier. Surface mount technology inductors and capacitors are implemented to realize the lumped-element transition. A prototype of the proposed HMSIW amplifier shows 15 dB gain with 3 dB bandwidth of 4 to 7.05 GHz in a simulation and measurement.

• 전력전자학회논문지
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• 제17권3호
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• pp.238-245
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• 2012

This paper presents a sensorless speed control of a 2-phase switch reluctance motor(SRM). The proposed sensorless control scheme is based on the slide mode observer with parameter compensator to improve the estimation performance. In the stand still position, the initial rotor position is determined by pulse current responses of each phase windings and the current difference. In order to determine an accurate initial rotor position, the two initial rotor positions are estimated by the difference of the pulse currents. From the stand still to the operating region, a simple open loop control which determines the commutation sequence by the pulse current of the unexcited phase winding is used. When the motor speed is reached to the sensorless control region, the estimated rotor position and speed by the slide mode observer are used to control the SRM. The flux calculator used in the slide mode observer is designed by phase voltage and the voltage drops in the phase resistance of the winding. The accuracy of the flux calculator is dependent on the phase resistance. For the continuous update of the phase resistance, current gradient at the inductance break point is used in this paper. The error of the estimated rotor position at the current gradient position is used to update the phase resistance to improve the sensorless scheme. The proposed sensorless speed control scheme is verified with a practical compressor used in home appliances. And the results show the effectiveness of the proposed control scheme.

• 한국항행학회논문지
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• 제20권5호
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• pp.433-439
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• 2016

저가형 GNSS (global navigation satellite system) 수신 모듈에 DGNSS (differential GNSS) 서비스를 적용하기 위한 방안으로 거리 영역의 보정정보를 위치 영역으로 투영한 후, stand-alone으로 산출한 위치에 적용하는 DGNSS-CP 방식이 제안된 바 있다. DGNSS-CP 를 상용 수신기 또는 휴대폰에 적용하기 위해서는 항법 방정식의 관측행렬을 이용하여 위치영역 투영 방정식을 구성하므로, 각 위성의 시선벡터를 산출하여야 한다. GNSS 항법 메시지, 배치 정보 등이 시선벡터 산출을 위하여 사용되는데, 각 방법에 따라 정확도와 연산량 등의 성능에 차이가 발생한다. 본 연구에서는 제시된 두 가지 시선벡터 산출 방식에 따라 DGNSS-CP의 성능에 어떠한 영향을 끼치는지 확인하기 위하여, Septentrio PolaRx4 Pro 수신기에서 stand-alone mode 로 저장된 데이터에 해당 알고리즘을 적용하였고, 배치 정보를 사용하는 방법이 궤도정보를 사용하는 방법에 비해 정확도 면에서는 그 성능이 RMS (root mean square) 0.1 m 가량 저하되는 반면, 연산량은 약 1/15수준으로 줄일 수 있음을 확인하였다.

• 제어로봇시스템학회논문지
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• 제14권7호
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• pp.711-719
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• 2008

Although non-real time simulation and pilot based evaluations are available for the development of flight control computer prior to real flight tests, there are still many risky factors. The control law designed for prototype aircraft often leads to degraded performance from the initial design objectives, therefore, the proper evaluation methods should be applied such that flight control law designed can be verified in real flight environment. The one proposed in this paper is IFS(In-Flight Simulator). Currently, this system has been implemented into the F-18 HARV(High Angle of Attack Research Vehicle), SU-27 and F-16 VISTA(Variable stability. In flight Simulation Test Aircraft) programs. This paper addresses the concept of switching mechanism for FLCC(Flight Control Computer)-SWMC(Switching Mechanism Computer) using 1553B communication based on flight control law of advanced supersonic trainer. And, the fader logic of TFS(Transient Free Switch) and stand-by mode of reset '0' type are designed to reduce abrupt transient and minimize the integrator effect in pitch axis control law. It hans been turned out from the pilot evaluation in real time that the aircraft is controllable during the inter-conversion process through the flight control computer, and level 1 handling qualities are guaranteed. In addition, flight safety is maintained with an acceptable transient response during aggressive maneuver performed in severe flight conditions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.181-184
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• 2004

There are reports showing that electromagnetic fields (EMFs) emitted at non-thermal levels may be associated with biological alterations in target cells. In this study it is objected to assess the potential influences of EMFs produced by cellular phones on fetal heart rate. Non Stress Test (NST) is a widely used method of fetal monitoring and assessing fetal health and well-being. Sixty volunteers with uncomplicated term pregnancies were studied by a Spacelabs AM-67 Doppler ultrasound monitor. Fetal Heart Rate recordings were obtained while there were no Cellular Phone around for 10 minutes. Afterwards, all patients were exposed to EMFs for 10 minutes. NST was performed while they were holding the CP on stand-by mode and then on dialing mode, each for 5 minutes. The recordings were analyzed with respect to baseline heart rate, accelerations and decelerations. The Wilcoxon matched-pairs signed-ranks test was used to compare these variables. The results indicate that EMFs emitted by CP do not cause any demonstrable effects on baseline FHR, acceleration or deceleration.

• 전력전자학회논문지
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• 제17권4호
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• pp.315-321
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• 2012

The utility-interactive inverter with critical loads should supply continuous and stable voltage to critical loads even during the grid fault. The conventional control method which performs current control for grid-connected mode and voltage control for stand-alone mode undergoes the critical load voltage variation during grid fault. The critical load voltage may have large transient when the inverter performs mode transfer after the islanding detection. Recently, the indirect current control method which does not have the transient state during not only islanding detection but also the mode transfer has been proposed. However, since the voltage control is maintained even during the grid-connected mode it is difficult to detect the islanding. This paper proposes an active anti-islanding method suitable for the indirect current control method which does not have NDZ(Non-Detection Zone).

• 한국소음진동공학회논문집
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• 제12권3호
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• pp.181-186
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• 2002

A seismic analysis is one of crucial design procedures of an axial blower used in nuclear power Plants. The blower should be operated even in ar emergency such as an earthquake. The blower should be designed in order to stand against an earthquake. For the seismic analysis, Ive perform the modal analysis and then evaluate the required response spectrum (PRS) from the given floor response spectrum (FRS). A finite element model of the blower is established by using a commercial FEM code of ANSYS. After the finite element modeling. the natural frequencies. the mode shapes and the participation factors are obtained from the modal analysis. The PRS is acquired by a numerical approach on the basis of the principle of mode superposition. We verify the structura safety of the axial blower and confirm the validity of the present seismic analysis results.