• 전기전자학회논문지
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• 제23권2호
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• pp.552-556
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• 2019

본 논문에서는 전류 제어 회로를 이용하여 load Transient response 특성을 향상시킨 capless LDO(low drop-out) 레귤레이터를 제안하였다. LDO 레귤레이터 내부의 오차증폭기와 패스 트랜지스터 사이에 전류 조절 회로를 두어 전압 라인에 들어오는 전류특성을 개선시켜 기존의 LDO 레귤레이터보다 향상된 transient 응답특성을 갖는다. 제안된 회로는 cadence의 virtuoso, spectre 시뮬레이터를 이용하여 0.18 um 공정에서 특성을 분석하였다. 실험 결과에 따르면, 제안된 회로 구성을 이용한 LDO의 load transient response는 기존 LDO과 비교하여 부하 전류가 rising time인 경우 1.954 us에서 1.378 us, falling time인 경우 19.48 us에서 13.33 us으로 약 29%, 28% 개선된 응답속도를 가진다.

• 한국군사과학기술학회지
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• 제26권1호
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• pp.1-9
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• 2023

The skin structure of sensor pod mounted on the exterior of aircraft can be exposed to the acoustic dynamic load and static load such as aerodynamic pressure and inertial load during flight. Fatigue life prediction of structural model under acoustic load should be performed and also differential stiffness of model modified by static load should be considered. The acoustic noise test spectrum of MIL-STD-810G was applied to the structural model and the stress response power spectral density (PSD) was calculated. The frequency response analysis was performed with or without prestress induced by inplane static load, and the response spectrum was compared. Time series data was generated using the calculated PSD, and the time and frequency domain fatigue life were predicted and compared. The variation of stress response spectrum due to static load and predicted fatigue life according to the different structural model considering mean stress were examined and decreasing fatigue life was observed in the model with prestress of compressive static load.

• 대한조선학회지
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• 제21권1호
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• pp.13-20
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• 1984

As the first step to the dynamic stress analysis of structures, transient responses of a Timoshenko beam with variable section subject to impact load are analyzed. According to the various characteristics of impact load, time histories of the transient response of Timoshenko beam with general boundary conditions are obtained and compared with those of one degree of freedom system. Numerical solutions of the governing equations of motion are calculated by adopting the equivalent lumped-mass system and the finite difference method. It is found that the dynamic responses of Timshenko beam depend on the effect of concentration and location of impact load. As a result, increasing tendency of fluctuation in dynamic response, especially in bending moment, is found according to the increase of load concentration factor in time and space.

• 디지털융복합연구
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• 제6권2호
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• pp.117-125
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• 2008

High-volume web sites often use clusters of servers with load balancing as a way to increase the performance, scalability, and availability of the sites. Load balancing, usually performed by load balancer in front of such clusters, is a technique to spread workload between several computers or resources, in order to get optimal resource utilization or response time. In this paper we examine the performance for several configurations of cluster-based web servers using a simulation approach. We investigate two types of buffering scheme (common and local) for web clusters and three load balancing policies (uniformly random, round robin, and least queue first), using response time as a performance measure. We also examine two basic approaches of scaling web clusters: adding more servers of same type or upgrading the capacity of the servers in the clusters.

• 전기학회논문지
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• 제58권1호
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• pp.28-34
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• 2009

In this study firstly we survey the calculation method and the characteristics of the way of estimating CBL(Customer BaseLine Load) that is important calculation tool for DRP internationally. Also we analyze the power consumption pattern using the 15 minutes load profiles of about 120,000 customers in domestic. Based on this pattern, we provide the CBL calculation method that can be utilized in DRP to save the cost, and analyze the accuracy of the CBL calculation proposed in this paper through the simulation.

• Journal of Power Electronics
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• 제4권2호
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• pp.87-95
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• 2004

A new fast-response high-current clamp DC-DC converter circuit design is presented that will meet the requirements and features of the new generation of microprocessors and digital systems. The clamp in the proposed converter amplifies the current in case of severe load changes and is able to produce high slew rate of output current and capability to keep constant the output voltage. This proposed high-current clamp technique is theoretically loss less, low cost and easy to implement with simple control scheme. This is modified from a basic buck topology by replacing the output inductor with two magnetically coupled inductors. Inductors are difference in inductance, one has large inductance and other has small inductance. The inductor with small inductance will take over the output inductor during fast load transient. It speedup the output current slew rate and reduce the output voltage drop in the case of heavy burden load changes.

• 설비공학논문집
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• 제11권5호
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• pp.684-691
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• 1999

A load calculation program based on TFM(Transfer function method) has been proposed in this study. The validity of the current method has been verified by comparing heat gain calculation by TRF(Thermal response factor) with that by CTF(Conduction transfer function) adopted in ASHRAE. In addition, it seems that the CTF coefficients given in ASHRAE tables have somewhat ambiguity The load calculation program developed in the current study has been employed to calculate cooling load from the exterior walls and roof of example 6 in the ASHRAE. The results are found in good agreement.

• 한국지진공학회논문집
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• 제24권1호
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• pp.39-47
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• 2020

Lightly reinforced concrete (RC) moment frames may suffer significant damage during large earthquake events. Most buildings with RC moment frames were designed without considering seismic loads. The load-displacement response of gravity load designed frames could be altered by masonry infill walls. The objective of this study is to investigate the load-displacement response of gravity load designed frames with masonry infill walls. For this purpose, three-story gravity load designed frames with masonry infill walls were considered. The masonry infilled RC frames demonstrated larger lateral strength and stiffness than bare RC frames, whereas their drift capacity was less than that of bare frames. A specimen with a partial-height infill wall showed the least drift capacity and energy dissipation capacity. This specimen failed in shear, whereas other specimens experienced a relatively ductile failure mode (flexure-shear failure).

• 대한조선학회논문집
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• 제43권4호
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• pp.484-493
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• 2006

Recently, direct load analysis using ship motion program is required to confirm structural safety for the Post-Panamax class large container carrier. However, there is no exact comparative study data for structural response between 20 and 30 wave load. So, in this paper, to compare the hull girder stress response between 20 versus 3D wave load calculation method, direct load analysis and global F.E analysis have been performed for three kinds of large container vessels using each 20 and 30 wave load calculation program. The results of 2D wave load RAO(Response Amplitude Operator) of each dominant load parameter(vertical, torsional and horizontal moment) are generally bigger than that of 30 results, especially in vertical wave bending moment. And the results of structural analysis based on the equivalent design wave method shows that there is a big difference in view of stress, but the stress distribution is very similar for each wave load case.

• 한국구조물진단유지관리공학회 논문집
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• 제22권6호
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• pp.105-113
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• 2018

교량 내하력 추정을 위해 제안된 모델에서는 응답계수를 충격계수 응답스펙트럼을 활용하여 산정하고 있다. 이때 충격계수 응답스펙트럼은 오일러-베르누이 보 모델을 바탕으로 차량이동하중이 교량의 폭 방향으로 중앙부에 재하 된 조건으로 생성된 결과이다. 따라서 중앙부 차량재하가 아닌 편측 이동하중재하 시 충격계수와 응답계수의 변화를 분석해 볼 필요가 있다. 이를 위해 본 연구에서는 폭이 10m인 2차선 단순교를 대상으로 이동하중해석을 실시하여 최대 충격계수와 응답계수 변화를 분석하였다. 수치해석 결과, 중앙부 재하조건 대비 편측 재하조건 적용 시 최대 정적 및 동적 변위 모두 증가하지만 동적변위 보다 정적변위의 증가량이 더 크기 때문에 충격계수는 오히려 감소하게 된다. 하지만 이러한 차이는 0.5%p 미만으로서 그 영향이 크지 않다. 그리고 응답계수의 경우, 편측 재하조건으로 인해 정적응답계수보다 동적응답계수에서 차이가 더 크게 나타나지만 편측 재하에 따른 오차율의 차이는 0.18%p 정도로 매우 작았다. 즉, 편측 이동하중재하가 응답계수에 미치는 영향은 거의 없으며, 응답계수 산정에 있어서 중앙부 이동하중재하 조건으로 생성된 충격계수 응답스펙트럼을 활용하여도 충분한 예측이 가능하다고 판단된다.