• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.112-115
• /
• 2002

Previous AC/DC PFC Boost Converter perceives feed forward signal of input and feedback signal of output for average current-mode control. Previous Boost Converter, the quantity of input current will be decreased by the decrease of output current in light load, and also power factor comes to be decreased. Also the efficiency of converter will be decreased by the decrease of power factor. The proposed converter presents the good PFC(Power Factor Correction), low line current hormonic distortions and tight output voltage regulations using non-dissipative snubber. The proposed converter also has a high efficiency by non-dissipative snubber circuit. To show the superiority of this converter is verified through the experiment with a 640W, 100kHz prototype converter.

• Journal of information and communication convergence engineering
• /
• 제14권3호
• /
• pp.191-199
• /
• 2016

In this study, we investigate the safety requirements and test methods of a radiofrequency stimulator. The main test items include controls of a minimum output, accommodation range, and output parameters that have been known as the safety requirements in conformity with international standards. As the test criteria for controlling the minimum output, an increase or decrease in a unit of 1 mA or 1 V or less was applied to the output amplitude regulator for both continuous and discontinuous control, and the output at the minimum setting was manipulated to not exceed 2% of the maximum setting. For controlling the output parameters, one of the representative test criteria states that the current limit of 250 mA should be equal to or less than 1,500 Hz. Consequently, when applying the radiofrequency stimulator on the human body, we need to ensure that the safety requirements conform to the international standards.

• 전기학회논문지P
• /
• 제63권3호
• /
• pp.212-217
• /
• 2014

The electric power output characteristics of magnesium fuel cell were investigated with regard to internal resistance. A equivalent circuit with the series-connected three internal resistance was introduced to analyze of the response to change of power. The power output analysis was employed in order to investigate the effect of internal resistances for the electrolyte concentration, air electrode area, Mg electrode area and distance between the electrodes. It was confirmed that internal resistance is generated by the electrolyte, air electrode and metal electrode, then those Internal resistances had a significant effect on the power output decrease. The power output was a maximum when the load resistance maches the internal resistance of the magnesium fuel cell. The fuel efficiency was only 50% at maximum power output. Higher fuel efficiency was achieved when the load resistance is greater than the internal resistance.

• 한국기계가공학회지
• /
• 제20권9호
• /
• pp.11-19
• /
• 2021

Linear variable differential transformer (LVDT) is a displacement sensor and is commonly used owing to its wide measurement range, excellent linearity, high sensitivity, and precision. To improve the output characteristics of LVDT, a few studies have been conducted to analyze the output using a theoretical method or a finite element method. However, the material properties of the core and the electromagnetic force acting on the core were not considered in the previous studies. In this study, a finite element analysis model was proposed considering the characteristics of the LVDT composed of coils, core, magnetic shell and electric circuit, and the core displacement. Using the proposed model, changes in sensitivity and linear region of LVDT according to changes in process and material parameters were analyzed. The outputs of the LVDT model were compared with those of the theoretical analysis, and then, the proposed analysis model was validated. When the electrical conductivity of the core was high and the relative magnetic permeability was low, the decrease in sensitivity was large. Additionally, an increase in the frequency of the power led to further decrease in sensitivity. The electromagnetic force applied on the core increased as the voltage increased, the frequency decreased, and the core displacement increased.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.4-7
• /
• 1997

When we use Hadamard transform spectrometers (HTS), we can increase signal to noise ratio(SNR) by multiplexing which is done by masks. But if the mask has a single defective element, output-SNR decreases. In this paper the effect of a single defective element on the output-SNR is investigated. And a method of compensating for the defective mask element is presented.

• 자원환경지질
• /
• 제57권2호
• /
• pp.129-141
• /
• 2024

본 연구는 지역산업연관표를 이용하여 생산-생산 승수를 도출하고 비금속광물 부문과 콘크리트 제품 부문을 통해 골재의 유발효과를 추정하였다. 유발효과를 파악할 수 있도록 지역산업연관표를 활용하여 분석을 진행하였다. 골재의 유발효과를 도출함에 있어 지역산업연관표를 이용하는 것은 부문분류 문제로 인해 어려움이 있는데, 본 연구는 골재를 포함한 비금속광물 부문을 골재로 간주한 분석과 골재생산의 대부분을 수요하는 콘크리트 제품 부문을 분석함으로써 부문분류 제약으로 인한 난점을 완화하고자 하였다. 산업연관효과를 추정하는 과정에서 골재의 생산감소 상황을 전제해 진행하였으며, 콘크리트 제품 부문을 분석하는 과정에서는 골재 생산감소로 인한 콘크리트 제품 생산감소의 효과, 즉 골재 1단위 생산감소는 콘크리트 제품 부문 0.8511단위의 생산감소를 전제로 분석하였다. 지역산업연관표가 구분하고 있는 17개 광역시도에 대해 자기지역 내 및 지역간 유발효과를 산출하였다. 골재 생산감소로 인해 자기지역에서 발생하는 생산감소 효과는 지역별 평균 1.28의 유발효과를 보였으며, 타지역의 골재 생산감소로 인한 생산감소 효과는 지역별 평균 0.10의 유발효과를 보였다. 취업효과도 산출하였는데, 지역별 골재 및 콘크리트 제품 부문의 규모에 따른 차이를 나타낼 수 있도록 10% 생산감소 상황을 전제하여 취업효과를 산출하였다.

• 오토저널
• /
• 제5권1호
• /
• pp.89-93
• /
• 1983

This paper describes on experimental investigation into the heat dissipation of Diesel engine, placing emphasis on the variations of compression ratio and cooling water temperature. The engine used for this test was a vertical single-cylinder four-cycle type, having a direct injection. Engine performance and heat transfer rates was tested under the compression ratio 14.3 and 17.4. In this study, the results showed that output and transfer rates of engine decrease in accordance with the decrease of compression ratio. The effect of cooling water temperature and injection delay of fuel on the heat dissipation brings about the decrease of heat transfer rates from cylinder to cooling water.

• 조명전기설비학회논문지
• /
• 제23권12호
• /
• pp.96-105
• /
• 2009

태양광발전소 두 곳을 샘플링하여 출력저하의 요인 중 우리나라 실정에 맞지 않는 입사각에 따른 태양전지 어레이 간의 음영에 의한 출력저하를 비교 분석하여 설비용량, 설비사양, 부지면적의 변화 없이 태양전지 어레이의 재배치를 통해 최대 출력을 낼 수 있는 태양전지 어레이의 최적 간격을 산정한다. 태양전지 어레이 1열 재배치 시에는 약 1.2[%], 2열 재배치 시에는 약 2.8[%], 3열 재배치 시에는 약 5.0[%]의 출력이 향상되었다. 또한 1열 재배치 시에는 태양전지 어레이 당 0.39[m], 2열 재배치 시에는 태양전지 어레이 당 0.82[m], 3열 재배치 시에는 태양전지 어레이 당 1.29[m]의 간격 이득을 얻었다. 태양전지 어레이 간격에 이득이 생기면서 음영의 영향을 받게 되는 시간이 점점 늦춰지게 되고 결국 출력의 향상이 나타나는 결과를 보였다.

• KDI Journal of Economic Policy
• /
• 제46권2호
• /
• pp.45-74
• /
• 2024

The import content of export (ICE) has served as an indicator of global integration for several decades. It is defined as the share of imported products embodied in exports and can be interpreted as the relative degree of the utilization of global production network (GPN) over the domestic supply chain (DSC) in terms of 'value-added.' This paper proposes two new indicators of global integration. They are defined as the ratios of imports (foreign products) to gross output (domestic products) generated by exports and can be interpreted as the relative degrees of the utilization of GPN over DSC in terms of 'production.' Both indicators are easy to compute and can be compared between years, between countries, between industries, and between groups of industries. The paper applies the new indicators to the recent edition of the OECD's Input-Output Database. Finally, the paper shows that the recent slowdown in international trade is mostly due to the decrease in the international trade of intermediate goods, with significant implications regarding the future of global integration.

• Nuclear Engineering and Technology
• /
• 제35권5호
• /
• pp.399-411
• /
• 2003

A model predictive control method is applied to design an automatic controller for thermal power control in a reactor core. The basic concept of the model predictive control is to solve an optimization problem for a finite future at current time and to implement as the current control input only the first optimal control input among the solutions of the finite time steps. At the next time step, the second optimal control input is not implemented and the procedure to solve the optimization problem is then repeated. The objectives of the proposed model predictive controller are to minimize the difference between the output and the desired output and the variation of the control rod position. The nonlinear PWR plant model (a nonlinear point kinetics equation with six delayed neutron groups and the lumped thermal-hydraulic balance equations) is used to verify the proposed controller of reactor power. And a controller design model used for designing the model predictive controller is obtained by applying a parameter estimation algorithm at an initial stage. From results of numerical simulation to check the controllability of the proposed controller at the $5\%/min$ ramp increase or decrease of a desired load and its $10\%$ step increase or decrease which are design requirements, the performances of this controller are proved to be excellent.