• Nuclear Engineering and Technology
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• 제56권2호
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• pp.485-497
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• 2024

Ring beam is the main anchorage zone of the tendons in the nuclear power prestressed concrete containment vessel (PCCV). Its safety is crucial and has a great influence on the overall performance of PCCV. In this paper, two half-scale ring beams were tested to investigate the mechanical performance of the anchorage zone in the PCCV under multidirectional pressure. The effect of working condition with different tension sequences was investigated. Additionally, a half axisymmetric plane model of the containment was established by the finite element simulation to further predict the experimental responses and propose the local reinforcement design in the anchorage zone of the ring beam. The results showed that the ultimate load of the specimens under both working conditions was greater than the nominal ultimate tensile force. The original reinforcement design could meet the bearing capacity requirements, but there was still room for optimization. The ring beam was generally under pressure in the anchorage area, while the splitting force appeared in the under-anchor area, and the spalling force appeared in the corner area of the tooth block, which could be targeted for local strengthening design.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1107-1115
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• 2013

A new PWM technique for a two-phase BLDC motor fed by a two-phase eight-switch inverter is proposed in this paper. It is well known that a two-phase eight-switch inverter can significantly improve power output compared with a two-phase six-switch inverter in a two-phase motor drive. To drive the two-phase BLDC motor simply and effectively, two normal PWM strategies are investigated to manage speed regulation. However, under the conditions of low speed and light load, especially during the braking process, the current in a short time of one period is near zero, which is a discontinuous waveform every half period. To solve it, a novel PWM technique is investigated to improve the operational performance of normal technique. Using the new PWM scheme, the current continues every half period and the braking performance is improved. The effectiveness of the proposed PWM method is verified through the experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.25-27
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• 2006

This paper proposes a new full ZVS-range asymmetrical half bridge converter. It uses the variable transient current build-up technique with the load variations. The current build-up is accomplished by using the secondary synchronous switch control. Due to the blocking capacitor in secondary side, the voltage applied to leakage inductor varies with the load variations during current build-up period. Therefore, the unnecessary current build-up of leakage inductor current in heavy load condition is prevented and more current build-up in medium and light load condition is achieved for ZVS operation. That is, the variant current build-up with the load variation is accomplished for the ZVS operation. Furthermore, the DC offset of the transformer magnetizing current is also eliminated and the utilization of magnetic core is maximized.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.243-249
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• 2005

To improve the ride comfort and handling characteristics of a vehicle, an active suspension which is controlled by external actuators can be used. An active suspension can control the vertical acceleration of a vehicle and the tire deflection to achieve the desired suspension goal. For this purpose, Model Predictive Control (MPC) scheme is applied with the assumption that the preview information of the oncoming road disturbance is available. The predictive control approach uses the output prediction to forecast the output over a time horizon and determines the future control over the horizon by minimizing the performance index. The developed method is applied to a half car model of four degrees-of-freedom and numerical simulations show that the MPC controller improves noticeably the ride qualities and handling performance of a vehicle.

• Journal of the Korean Data and Information Science Society
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• 제21권2호
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• pp.317-325
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• 2010

In this paper, we develop four modified empirical distribution function (EDF) type tests using approximate maximum likelihood estimators for the half-logistic distribution based on multiply Type-II censored samples. We also propose modified normalize sample Lorenz curve polt and new test statistics. We compare the above test statistics in the sense of the power for various censored samples. We present an example to illustrate this method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.523-526
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• 2010

FM 무전기는 반이중통신(Half-duplex)방식을 사용한다, FM 무전기를 DCE(Data Circuitterminating Equipment)로 사용하고 다수의 가입자가 정보교환을 수행하는 통신망에서 데이터 전송이 일어나고 있는지를 검출하고 데이터 전송 시 충돌을 방지하기 위해 Network Access Control을 사용한다. 본 논문에서는 현재 우리 군에서 운용하고 있는 FM무전기를 사용하는 통신망에서 MIL-STD-188-220C의 Network Access Control 방법 중 R-NAD(Random Network Access Delay)를 적용한 MPC8260 Power QUICC 기반의 디지털 메시지 전송장비에 대하여 연구한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1416-1418
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• 2005

This paper presents a new hybrid control method of asymmetrical half-bridge converter(AHBC) with low voltage stresses of the diodes and interleaved PFC(power factor correction). The proposed new control scheme can observe variation of secondary diodes voltage stresses by variation of duty ratio and then decide the control portions which are asymmetrical control and PFM(Pulse Frequency Modulation). Therefore, the proposed control scheme has many advantages such as a low rated voltage of the secondary diodes, low conduction loss according to the low voltage drop and wide zvs range by load variation. Through simulation results, the validity of the proposed control scheme is demonstrated.

• 전력전자학회논문지
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• 제22권4호
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• pp.336-344
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• 2017

This paper presents the three-port DC-DC converter modeling and controller design procedure, which is part of the solid-state transformer (SST) to interface medium voltage AC grid to bipolar DC distribution network. Due to the high primary side DC link voltage, the proposed converter employs the three-level neutral point clamped (NPC) topology at the primary side and 2-two level half bridge circuits for each DC distribution network. For the proposed converter particular structure, this paper conducts modeling the three winding transformer and the power transfer between each port. A decoupling method is adopted to simplify the power transfer model. The voltage controller design procedure is presented. In addition, the output current sharing controller is employed for current balancing between the parallel-connected secondary output ports. The proposed circuit and controller performance are verified by experimental results using a 30 kW prototype SST system.

• E2M - 전기 전자와 첨단 소재
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• 제8권3호
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• pp.254-260
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• 1995

A method is described for the design and fabrication of the sensor interface circuits on the Clark electrodes for the dissolved oxygen(DO). The discussion includes a method for the +5 V single-supply driving for the sensor circuits, which has low power comsumption for the front-end electronics. DO probe under test is composed of the Clark electrode with silver anode, gold cathode and the electrolyte of half saturated KCI solution and the FEP teflon memtrance for the oxygen penetration. Typical polarograms for the DO probes by using this sensor circuit reveals high accuracy over 99% of the I to V conversion. Partial pressure of oxygen obtained from the polarograms are well suited to the results calculated. It is expected that the proposed sensor circuits can be utilized into the customized IC for the battery-driven small-size DO meters.

• 한국컴퓨터정보학회논문지
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• 제5권2호
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• pp.105-114
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• 2000

본 논문에서는 1차원 움직임을 갖는 신호원의 위치를 실시간으로 탐지하기 위해 N개의 안테나를 반원형 구조로 배열하였고, 각각의 수신어레이로부터 수신 전력패턴과 3차 spline 보간법만을 사용하여 신호원의 입사각을 추정하고, 이로부터 신호원의 수평이동 좌표를 화면에 실시간으로 표시하는 시스템을 구현한 논문이다. 본 논문에서 사용한 신호원은 X 대역의 10.52GHz로 10-20dBm 사이의 송신출력으로 하였고, 신호원의 위치를 좌.우 ${\pm}15^{\circ}$ 이내의 임의의 좌표로 수평 이동하면서 제시한 방법의 타당성을 검증하고자 한다.