• 조명전기설비학회논문지
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• 제27권1호
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• pp.68-75
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• 2013

This paper presents a scheme to improve transient stability using Newton's Approach for generation rescheduling. For a given contingency, the energy margin and sensitivities are computed. The bigger energy margin sensitivity of generator is, the more the generation of the generator effects to the transient stability. According to energy margin sensitivity, the control variables of generation rescheduling are selected. The fuel cost function is used as objective function to reallocate power generation. The results are compared to the results of time simulation to show its the effectiveness.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.65-68
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• 2006

Experiments were performed to investigate the effects of mud-flap width on the aeroacoustic noise generation inside high-speed trains. The open-circuit type wind tunnel was used. The measurement setup was custom-built to simulate intercoach spacing. From the measurements, the characteristics of the turbulent flow after the intercoach spacing and consequent generation of aeroacoustic noise inside the cabin was investigated. Especially the effects of mud flap length on the characteristics of the characteristics of the turbulent flow were identified. The mechanism of noise generation by analyzed interactions with structure vibration characteristics and generation characteristics of blocked pressure was investigated.

• 한국광학회:학술대회논문집
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• 한국광학회 1998년도 제15회 광학 및 양자전자 학술발표회 논문집
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• pp.68-69
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• 1998

• 한국지능시스템학회논문지
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• 제19권1호
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• pp.62-68
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• 2009

수정된 PCX(parent-centric recombination) 연산자와 결합한 두 가지 새로운 세대차 모델이 제안된다. 첫째, 자가적응 세대차 모델(SGG, self-adaptation generation gap)은 자손에 의한 부모의 대치 확률을 일정한 수준으로 유지하는 제어 방식이다. 둘째, 가상 클러스터 세대차(VCGG, virtual cluster generation gap)는 클러스터링을 통해 부모간의 거리를 조정해 주며, 이로 인해 개체들이 다양화 될 수 있다. 이 모델에서 부모간의 거리는 클러스터의 크기로 조절된다. 제안된 두 가지 접근법의 효용성을 입증하기 위해서 3 가지 표준적인 문제에 대한 실험이 수행되었다. 가장 최근의 경쟁력 있는 접근법인 CMA-ES와 G3-PCX와 비교한 결과, 제안된 두 기법 모두 기존의 접근법들 보다 우수함을 보여준다.

• 응용통계연구
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• 제27권2호
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• pp.211-226
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• 2014

국민연금 노령연금 수급자를 대상으로 소득계층별 차별 사망력과 기대여명을 산출하고, 그 결과를 반영하여 노령 연금 수급자의 수급부담구조를 분석하였다. 분석을 위해 노령연금 수급자의 소득계층에 대한 구분은 생애평균소득을 기준으로 3분위로 세분화하였으며, 사망확률 추정을 위해서 사용된 함수는 고연령 사망확률 추정에 주로 사용되는 gompertz모형을 사용하였다. 산출된 기대여명을 이용하여 소득계층별로 생애 총 연금급여액 규모를 추정함으로서 수익비, 내부수익률 및 후세대 부담전가량 분석의 정확성을 높이는데 기여하였다. 기대여명 추정 결과 60세 남자의 기대여명은 약 23.10년이며, 소득계층별로는 21.69~24.63년의 차이를 보이고 있다. 60세 여자의 기대여명은 약 28.84년이며, 소득계층별로는 27.63~29.81년의 차이를 보이고 있다. 즉 하위소득계층의 기대여명의 경우 소득계층을 통합한 경우의 기대여명보다 1.21~1.41년 낮게 추정되었으며, 상위 소득계층의 경우에는 0.97~1.53년 높게 추정되었다. 산출된 기대여명을 사용하여 수익비를 분석한 결과 하위 소득계층의 경우 약 2.68~4.83% 낮게 분석되었으며 상위 소득계층의 경우에는 2.07~4.98% 높게 분석되었다. 내부수익률은 하위 소득계층의 경우 약 0.00~0.74% 낮고 상위 소득계층의 경우에는 0.03~1.73% 높게 분석되었으며, 후세대 부담전가량은 하위 소득계층의 경우 약 3.00~5.74% 낮고 상위 소득계층의 경우에는 2.53~9.68% 높게 분석되었다. 분석 결과는 노령연금 수급자에 대한 소득계층별 기대여명 추정을 통해 나타난 수급부담구조 분석의 결과로서, 기존의 소득계층별 기대여명을 고려하지 않은 시뮬레이션 분석과는 차별성이 있으며, 소득재분배 효과가 있는 국민연금 노령연금 수급자의 수급 부담구조분석 결과에 대한 대표성을 지닌다.

• 한국전기전자재료학회논문지
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• 제21권12호
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• pp.1071-1076
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• 2008

This paper presents the self power generation from vibration using the piezoelectric bimorph actuator. The piezoelectric bimorph actuator was well developed with PZT-PNN-Fe piezoelectric ceramics. As the applied voltage was increased, a linear change of displacement was obtained with a relatively high ratio of 12.53 um/V for the bimorph actuator. Moreover, when the motor's rotational speed was 2000 rpm, the bimorph actuator, which has a resonance frequency of 68 Hz, exhibited the most efficient generation voltage of 10.4 V. This bimorph actuator could make the LED, emitting 60 mW, working successfully. Therefore, it is anticipated that the bimorph actuator will be useful as a power source for the next-generation electronic devices.

• Journal of Electrical Engineering and Technology
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• 제2권1호
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• pp.68-80
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• 2007

This paper covers switched reluctance generator (SRG) and its comparison with induction and synchronous machines for distributed generation. The SRG is simple in design, robust in construction, and fault tolerant in operation; it can also withstand very high temperatures. However, the performance and cost of the SRG power electronics driver are highly affected by the topology and design of the converter. IGBT and MOSFET based converters are not suitable for very high power applications. This paper presents thyristor-based resonant converters which are superior candidates for very high power applications. Operations of the converters are analyzed and their characteristics and dynamics are determined in terms of the system parameters. The resonant converters are capable of handling high currents and voltages; these converters are highly efficient and reliable as well. Therefore, they are suitable for high power applications in the range of 1MW or larger for distributed generation.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.63-68
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• 2003

Recently, a fuel cell is remarkable for new generation system. The fuel cell generation system converts the chemical energy of a fuel directly into electrical energy. The fuel cell generation is characterized by low voltage and high current. For connecting to general load, it needs both a step up converter and an inverter. The step up converter makes DC to DC and the inverter changes DC to AC. In this paper, full bridge converter and the single phase inverter are designed and installed for fuel cell. Simulation and experimental results are displayed under several load conditions.

• Clinical and Experimental Pediatrics
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• 제56권2호
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• pp.68-74
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• 2013

Purpose: To evaluate the effectiveness of new management policies on the incidence of invasive Candida infections Methods: This observational study involved a retrospective analysis of the patients' medical records. In total, 99 very low birth weight infants, who were admitted to the neonatal intensive care unit at Ajou University Hospital from January 2010 to December 2011, were enrolled for the study. Period I, defined as the period before the revision of management policies, comprised 57 infants; whereas, period II, defined as the period after the implementation of new management policies, comprised 42 infants. The new management policies entailed a reduction in antibiotic and histamine type 2 receptor blocker (H2 blocker) use, duration of central venous catheterization, and duration of endotracheal intubation. Results: There was a significant overall decrease in the use of antibiotics including 3rd generation cephalosporin and H2 blockers (P<0.05), and a significantly lower incidence of invasive Candida infections in period II as compared to period I (0/42 vs. 6/57, respectively; P=0.037). Comparison between infants with invasive Candida infections (n=6) and those without (n=93) showed that gestational age (odds ratio [OR], 0.909; 95% confidence interval [CI], 0.829 to 0.996; P=0.042) and the duration of 3rd generation cephalosporin use (OR, 1.093; 95% CI, 1.009 to 1.183; P=0.029) were statistically significant risk factors. Conclusion: The new management policies effectively decreased overall use of antibiotics, especially 3rd generation cephalosporin, and H2 blockers, which led to a significantly lower incidence of invasive Candida infections.

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 하계학술발표회
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• pp.68-69
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• 2005