• 보건행정학회지
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• 제13권3호
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• pp.129-147
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• 2003

This study is to grasp a trend of profitability classified by characteristics of hospitals and to analyze related factors. Subjects are 145 hospitals which have gotten the standardization audit by Korean Hospital Association during 1998-200l. Profitability was measured in the aspect of operation profit rate with operating margin to gross revenue as proxy variables. Independent variables were classified by general factors (ownership, number of beds, period of establishment, competition), financial factors (liabilities to total assets, current ratio, fixed ratio, total asset turnover, inventories turnover), and factors related to patient treatment (average length of stay, bed occupancy rate, new outpatient ratio, admission ratio of outpatients, number of patients per specialist, personnel costs per adjusted inpatient, administrative costs per adjusted inpatient). Hierarchical multiple regression analysis model was used in this study. As a result of hierarchical multiple regression analyzation of operating margin to gross revenue, adjustive $R^2$ of general factors was relatively more powerful. The factors had significant effect on operating margin to gross revenue were ownership(+), number of beds(+), competition(+), current ratio(+), fixed ratio(+), total asset turnover(+), personnel costs per adjusted inpatient(-).

• 대한전자공학회논문지SD
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• 제47권7호
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• pp.1-7
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• 2010

Fin 폭이 다른 accumulation-mode Pi-gate p-채널 MOSFET의 고온특성을 측정 분석하였다. 사용된 소자는 Fin 높이는 10nm 이며 폭은 30nm, 40nm, 50nm 의 3종류이다. 온도에 따라서 드레인 전류, 문턱전압, subthreshold swing, 유효이동도 및 누설 전류 특성을 측정하였다. 온도가 증가할수록 드레인 전류는 상온에서 보다 약간 증가하는 현상이 나타났다. 온도에 따른 문턱전압의 변화는 inversion-mode 소자 보다 작은 것으로 측정되었다. 유효이동도는 온도가 증가할수록 감소하였으나 Fin 폭이 감소할수록 이동도는 큰 것을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제21권12호
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• pp.1111-1117
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• 2008

A transformer type superconducting fault current limiter (SFCL) is one of the fault current limiters which have been proposed to reduce the fault current in the transmission lines. This paper proposes the new circuit configuration of a transformer type SFCL and also investigates the operating characteristics of the transformer type SFCL containig the resistor in the tertiary winding. The proposed SFCL contains the resistor in the tertiary winding. The newly inserted resistor can divert the power which the High-Tc superconducting has to bear. Because the resistor in the tertiary winding relieves the power of the High-Tc superconducting, it is possible that the proposed transformer type SFCL can decrease the more larger fault current than the conventional SFCL with the same High-Tc superconducting. And the cost of the proposed transformer type SFCL can be reduced.

• 한국통신학회논문지
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• 제25권6B호
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• pp.114-114
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• 2000

In this paper, a current comparative frequency automatic tuning circuit for the CMOS bandpass filter are designed with the new architecture. And also, when the designed circuit is compared the typical tuning circuit, it has very simple architecture that is composed of the current comparator and charge pump and operated in 2V power supply. The proposed tuning circuit automatically compensate the difference between the operating current of the integrator and the reference current which is specified. Using CMOS 0.25um parameter, a CMOS bandpass active filter with center frequency(f0= 100MHz) is designed, and according to the transister size the variation of the center frequency is simulated. As the HSPIC simulation results, the tuning operating of the proposed current comparative frequency automatic tuning circuit is verified.

• 한국초전도ㆍ저온공학회논문지
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• 제14권3호
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• pp.28-32
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• 2012

The critical current of the HTS(High Temperature Superconductor) tape is governed by cooling temperature, magnetic field and its angle to HTS tape originated from its geometrical structure. At the HTS coil design stage, the critical current of the coil is calculated by considering the Ic-B characteristics of the 2G tape and the operating current is determined based on the critical current. The operating current and the structure of the 5 T coil are suggested through the FEM (Finite Elements Method) analysis and calculation. As a part of our on-going research on a 20 T LTS/HTS magnet, we have designed and constructed a 5 T HTS insert coil and tested it in liquid helium temperature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.252-254
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• 1994

This paper describes the control method in order that output current of a voltage source inverter tracks reference sinusoidal current so that its harmonic current components are reduced. Operating character of this inverter is analyzed with normalized values of parameter. And the method that apply multilayed feedfoeward neural networks, which play excellent steady state operation in control system, to inverter control system and training method are presented. Then, the output current of inverter which is driven by the proposed method. is considered throughout computer simulation and safe operating range of inverter parameter is resented.

• 한국통신학회논문지
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• 제25권6B호
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• pp.1114-1119
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• 2000

In this paper, a current comparative frequency automatic tuning circuit for the CMOS bandpass filter are designed with the new architecture. And also, when the designed circuit is compared the typical tuning circuit, it has very simple architecture that is composed of the current comparator and charge pump and operated in 2V power supply. The proposed tuning circuit automatically compensate the difference between the operating current of the integrator and the reference current which is specified. Using CMOS 0.25um parameter, a CMOS bandpass active filter with center frequency(fo=100MHz) is designed, and according to the transister size the variation of the center frequency is simulated. As the HSPICE simulation results, the tuning operating of the proposed current comparative frequency automatic tuning circuit is verified.

• 한국정보기술학회 영문논문지
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• 제8권2호
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• pp.59-67
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• 2018

The minimum power supply voltage of a typical bandgap current reference (BGCR) is limited by operating temperature and input common mode range (ICMR) of a feedback amplifier. A new BGCR using a bandgap voltage generator (BGVG) is proposed to minimize the effect of temperature, supply voltage, and process variation. The BGVG is designed with proportional to absolute temperature (PTAT) characteristic, and a feedback amplifier is designed with weak-inversion transistors for low voltage operation. It is verified with a $0.18-{\mu}m$ CMOS process with five corners for MOS transistors and three corners for BJTs. The proposed circuit is superior to other reported current references under temperature variation from $-40^{\circ}C$ to $120^{\circ}C$ and power supply variation from 1.2 V to 1.8 V. The total power consumption is $126{\mu}W$ under the conditions that the power supply voltage is 1.2 V, the output current is $10{\mu}A$, and the operating temperature is $20^{\circ}C$.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.543-550
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• 2016

The Active Superconducting Current Controller (ASCC) is a new type of Superconducting Fault Current Limiters (SFCL) which can limit the fault current in different modes. It also has the particular abilities of compensating active and reactive powers for electrical networks. In this paper, it is confirmed that the performance of ASCC in different operating modes introduces a limiting impedance in series with the network which can even degrade the transient stability and the operation of the Over-Current Relays (OCR) employed in a power system. In addition, the model of a three-phase ASCC is simulated, and the effect of descriptive modes on the current limiting level is investigated. For the transient stability analysis, a single machine-infinite bus system is tested, and the effect of operation modes is studied based on an equal area criterion obtaining the critical time and the critical angle. Modifying the setting parameters of OCR such as time dial and pick-up current, the protective coordination is also studied in different operating modes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.200-202
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• 2006

We investigated the operating characteristics of a flux-lock type superconducting fault current limiters according to the number of the serial connection each the superconducting element at the additive polarity winding of a transformer. This SFCL consists of two coils wound in parallel on the same iron core, and the secondary coil is connected to the elements in series. Operating characteristics can be controlled by adjusting the inductances and the winding directions of the coils. It turns ratio between the primary and the secondary coils is 63:21. The analysis of voltage, current, and resistance in serial connection each element was performed to increase the applied voltage of flux-lock type SFCL. When the applied voltage was 200/$\sqrt{3}[V_{rms}]$ with three elements connected in seres, the peak value of the line current increased up to 26,24[A]. On the other hands, resistive SFCL increased up to 36.35[A], under the same conditions. This enabled the flux-lock type SFCL to be easy to increase the capacity of power system.