• Steel and Composite Structures
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• 제21권1호
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• pp.93-107
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• 2016

Seismic fragility analysis is a probabilistic decision-making framework which is widely implemented for evaluating vulnerability of a building under earthquake loading. It requires ingredient named probabilistic model and commonly developed using statistics requiring collecting data in large quantities. Preparation of such a data-base is often costly and time-consuming. Therefore, in this paper, by developing generic seismic drift demand model for regular-multi-story steel moment resisting frames is tried to present a novel application of the probabilistic decision-making analysis to practical purposes. To this end, a demand model which is a linear function of intensity measure in logarithmic space is developed to predict overall maximum inter-story drift. Next, the model is coupled with a set of regression-based equations which are capable of directly estimating unknown statistical characteristics of the model parameters.To explicitly address uncertainties arise from randomness and lack of knowledge, the Bayesian regression inference is employed, when these relations are developed. The developed demand model is then employed in a Seismic Fragility Analysis (SFA) for two designed building. The accuracy of the results is also assessed by comparison with the results directly obtained from Incremental Dynamic analysis.

• 기본간호학회지
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• 제24권3호
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• pp.189-199
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• 2017

Purpose: This study was conducted to examine the level of agreement between a standardized patient (SP) and a faculty member in the evaluation of nursing students' assessment and communication skills. Methods: Participants were 51 third year nursing students in a simulation practice of 'nursing care for a patient admitted with chest pain'. Using a 30-item checklist and a 16-item communication tool, a SP and faculty member evaluated the students' assessment and communication skills during the simulation. Results: The average values for percent agreement and kappa statistic for nursing assessment between the two evaluators were 85.3% and .48 respectively. Twenty of thirty items evaluating assessment skill had above moderate agreement (${\geq}.41$) by kappa between the evaluators. Seven of sixteen items evaluating communication and interpersonal skills showed above fair agreement (${\geq}.40$) between the two evaluators, which was measured by intraclass correlation coefficient. Conclusion: The findings show that the evaluation of the SP was consistent with those of the faculty member to a moderate degree. Clear guidelines for evaluating criteria and optimal time and effort for SP training are necessary to increase the reliability of standardized patients as evaluators in simulation-based nursing education.

• 한국대기환경학회지
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• 제19권4호
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• pp.397-414
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• 2003

The performance of one-particle stochastic Lagrangian models for passive tracer dispersion are evaluated against measurements in horizontally-homogeneous neutrally-stratified atmospheric surface layer. State-of-the-technology models as well as classical Langevin models, all in class of well mixed models are numerically implemented for inter-model comparison study. Model results (far-downstream asymptotic behavior and vertical profiles of the time averaged concentrations, concentration fluxes, and concentration fluctuations) are compared with the reported measurements. The results are: 1) the far-downstream asymptotic trends of all models except Reynolds model agree well with Garger and Zhukov's measurements. 2) profiles of the average concentrations and vertical concentration fluxes by all models except Reynolds model show good agreement with Raupach and Legg's experimental data. Reynolds model produces horizontal concentration flux profiles most close to measurements, yet all other models fail severely. 3) With temporally correlated emissions, one-particle models seems to simulate fairly the concentration fluctuations induced by plume meandering, when the statistical random noises are removed from the calculated concentration fluctuations. Analytical expression for the statistical random noise of one-particle model is presented. This study finds no indication that recent models of most delicate theoretical background are superior to the simple Langevin model in accuracy and numerical performance at well.

• 한국재료학회지
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• 제20권6호
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• pp.338-343
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• 2010

As an alternative to the W plug used in MOSFETs, a Cu plug with a NiSi contact using Ta / TaN as a diffusion barrier is currently being considered. Conventionally, Ni was first deposited and then NiSi was formed, followed by the barrier and Cu deposition. In this study, Ti was employed as a barrier material and simultaneous formation of the NiSi contact and Cu plug / Ti barrier was attempted. Cu(100 nm) / Ti / Ni(20 nm) with varying Ti thicknesses were deposited on a Si substrate and annealed at $4000^{\circ}C$ for 30 min. For comparison, Cu/Ti/NiSi thin films were also formed by the conventional method. Optical Microscopy (OM), Scanning Probe Microscopy (SPM), X-Ray Diffractometry (XRD), and Auger Electron Microscopy (AES) analysis were performed to characterize the inter-diffusion properties. For a Ti interlayer thicker than 50 nm, the NiSi formation was incomplete, although Cu diffusion was inhibited by the Ti barrier. For a Ti thickness of 20 nm and less, an almost stoichiometric NiSi contact along with the Cu plug and Ti barrier layers was formed. The results were comparable to that formed by the conventional method and showed that this alternative process has potential as a formation process for the Cu plug/Ti barrier/NiSi contact system.

• 전자공학회논문지S
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• 제35S권2호
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• pp.31-39
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• 1998

In this paper, we have presented a quantitative performance effect of CCP(Call Control Processor) when SAAL(Signalling ATM Adaptation Layer) function is distributed from CCP to SIMs(Subscriber Interface Modules) in an ATM switching system with distributed architecutre. For the performance analysis, SLAM II simulation language is used and subscriber signalling messageand inter-processor communication messages according to Q.2931 based local call processing procedure are taken into consideration in the proposed queuing network model. The results of simulation are compared with in case of processing SAAL function on CCP. It is observed that the processing utilization of CCP reach 24,000 BHCA and 25,700 BHCAwhen SAAL function load amounts to 10% and 20% of the processing time of the total message, respectively. These values shows that the processing utilization of CCP is alleviated about 7% in comparison with 2,000 BHCA in case that SAAL function is carried out on CCP. Consquently, it is shown that we have to consider seriously how to distribute the functions concerning call processing in a large cale ATM switching system architecture accomodating a number of SIMs.

• 한국지능시스템학회논문지
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• 제13권4호
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• pp.455-460
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• 2003

본 논문에서는 퍼지 클러스터링 알고리즘에 의해 구해진 퍼지 분할에 대한 최적 클러스터 수를 결정하는 방법을 제안한다. 제안된 척도는 퍼지 클러스터들간의 중첩성과 분리성을 이용한다. 중첩성은 클러스터간 인접도를 이용하여 계산하며, 분리성은 데이터에 대한 상관성 정도로 나타낸다. 따라서 중첩성이 낮고 분리성이 높을수록 좋은 클러스터 결과라고 할 수 있다. 표준 데이터 집합을 대상으로 기존의 척도들과 비교 실험함으로써 제안된 척도의 신뢰성을 검증하였다.

• 한국지구과학회지
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• 제24권1호
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• pp.7-21
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• 2003

The state-of-art third generation wave prediction model WAM was applied to the Korean seas for a winter monsoon period of January 1997. The wind field used in the present study is the global NSCAT-ERS/NCEP blended winds, which was further interpolated using a bi-cubic spline interpolator to fine grid limited area shallow water regime surrounding the Korean seas. To evaluate and investigate the accuracy of WAM, the hindcasted wave heights are compared with observed data from two shallow water buoys off Chil-Bal and Duk-Juk. A detailed study has been carried with the various meteorological parameters in observed buoy data and its inter-dependency on model computed wave fields was also investigated. The RMS error between the observation and model computed wave heights results to 0.489 for Chil-Bal and 0.417 for Duk-Juk. A similar comparison between the observation and interpolated winds off Duk-Juk show RMS error of 2.28 which suggest a good estimate for wave modelling studies.

• 한국공작기계학회논문집
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• 제12권3호
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• pp.58-67
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• 2003

Welding characteristics of austienite 304 stainless and SM45C using a continuous wave Nd:YAG laser n experimentally investigated Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much Inter than those involved in conventional welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameter such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar and plates, etc. The Nd:YAG laser welding process is one of the most advanced manufacturing technologies owing to its high speed and penetration. This paper describes the weld ability of SM45C carbon steel for machine structural use by Nd:YAG laser. The follow conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/aspect ratio and hence a decrease in the fusion zone size. The penetration depth increased with the increase in laser power.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권5호
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• pp.309-317
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• 2004

This paper suggested the vibration characteristic improvement by variation mode of ring type ultrasonic motor. Design for the piezoelectric ceramic and elastic body of stator were calculated by the finite element method(FEM) that consider the resonance frequency, vibration mode and coupling efficiency etc. Through the result of vibration analysis from 6 order mode to 8 mode, the 7 order mode was gained very an excellent results that it was the coupling efficient, minimum power loss and bending vibration value. Here over 7 order mode, this paper was acquired that an output current for input voltage was very a large increased results. The result of vibration calculation, from thickness 0.5[mm] to 2[mm], knew the fact that the vibration displacement at 0.5[mm] is an high value too. From such result, this paper was manufactured the ultrasonic motor of outer diameter 5O[mm] , inter 22[mm] having the about 43.86[KHz] resonance frequency. We have gated that a simulation result is 42.2[KHz] and an experiment result is 43.86[KHzl The propriety of this paper was established though comparison. investigation of simulation and experiment result.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.139-143
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• 2001

Recently, the interest on power quality has been hot issue. The equipments cause voltage disturbance and has become more sensitive to the voltage disturbance. This paper deals with 5-Level H-Bridge Line-Inter active Dynamic Voltage Restorer(LIDVR) system. The LIDVR has following advantages in comparison with the DVR with series injection transformer It has the power factor near to unity under normal source voltage, can compensate the harmonic current of the load and the instant interruption, and has the fast response. First, the construction, the operation mode and algebraic modeling of LIDVR are reviewed. And then a voltage controller is proposed to get sinusoidal load voltage with constant amplitude. To find PWM method suitable for H-Bridge converter, two PWM methods are compared and analyzed. Finally, simulation results verify the proposed 5-level H-Bridge LIDVR system.