• 한국전산구조공학회논문집
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• 제25권2호
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• pp.149-154
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• 2012

도로교설계기준 내진설계편은 붕괴방지수준의 확보를 설계절차에 의해 규정하고 있는 반면 기능수행수준의 확보에 대한 요구사항은 명확하게 제시하고 있지 않다. 붕괴방지수준의 확보를 위해 기본적으로 제시된 설계방법은 응답수정계수를 사용하는 스펙트럼해석법으로, 기능수행수준은 설계과정에 적용되는 위험도계수와 응답수정계수에 의해 결정 되어진다. 위험도계수는 교량의 중요도에 따라 단순하게 적용할 수 있으나 중약진지역에서의 응답수정계수 적용은 설계조건에 따라 다른 결과를 갖게 된다. 이 연구에서는 중약진지역의 일반 도로교량을 대상으로 내진설계를 수행하여 기능수행수준의 결정과정을 검토하고, 이 결과를 토대로 기능수행수준의 확보와 관련하여 내진설계편에 보완해야 하는 사항을 제시하였다.

• 한국산학기술학회논문지
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• 제17권12호
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• pp.730-736
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• 2016

이전 연구에서 기존의 재하실험을 통한 교량의 공용 중 내하력 평가방법을 개선하기 위하여 충격계수 응답스펙트럼과 그에 따른 내하성능 변화 추정 방법이 제안되었다. 본 논문에서는 제안된 방법의 적용성을 검증하기 위하여 공용 중인 단순지지 단경간 교량에 대한 현장 동적특성 평가 실험을 수행하였다. 실험을 통해 상시 교통하중 상태에서 무선 가속도계를 이용하여 교량의 고유진동수 도출이 가능한 수준의 동특성 응답을 획득할 수 있었다. 대상 교량의 가속도 데이터로부터 동적거동은 1차 모드에 지배되며 준공 당시에 비해 공용 기간의 증가로 인해 고유진동수가 감소한 것으로 나타났다. 충격계수 응답스펙트럼으로부터 대상 교량의 발생 가능한 최대 충격계수를 추정하였다. 도출된 이전 및 현재의 고유진동수와 충격계수를 바탕으로 성능감소계수를 적용한 내하력 평가방법을 이용하여 성능변화를 추정하였다. 이전에 비해 공용내하력이 감소하였으나 설계 활하중을 상회하여 내하성능에는 문제가 없는 것으로 나타났다. 상시 교통하중 하에서의 가속도 계측 데이터와 충격계수 응답스펙트럼을 이용하는 제안된 내하성능 변화 추정 방법은 실제 교량에 적용 가능할 것으로 판단된다.

• International Journal of Quality Innovation
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• 제4권2호
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• pp.16-31
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• 2003

A reducing variation of quality characteristics is a typical example of quality improvement. In such a case, we treat the quality characteristic, as a response variable and need to find active factors affecting the response from many candidate factors since reducing the variation of the response will be achieved by reducing variation of the active factors. In this paper, we first derive a method of selecting an active factor by linear regression. It is well known that correlation between factors deteriorates the precision of estimators. We, therefore, examine robustness of the selecting method against the correlation in the data set and derive an evaluation method of the deterioration brought by the correlation. Furthermore, some examples of selecting and evaluation methods are shown to demonstrate practical usage of the methods.

• 기본간호학회지
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• 제23권2호
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• pp.115-125
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• 2016

Purpose: The purpose of this study was to use meta-analysis to evaluate factors and variables related to the emotional labor of hospital nurses. Method: The study included variables obtained from 66 recently published studies, doctoral dissertations, and master's theses. Results: The related variables were categorized into five factor groups: internal character factor, nursing care related factor, environmental factor, emotional response, and job response. For the defensive variable, job related response (effect size [ES]=-.17), environment (ES=-.14), internal character (ES=-.08), nursing care (ES=-.06), and emotional response (ES=-.06) showed significant effect size among the five categorized variable groups. For the risk variable, internal character (ES=.44), emotional response (ES=.46), environment (ES=.27), job related response (ES=.27), and nursing care (ES=.19) showed significant effect size among the five categorized variable groups. Conclusion: The results of this study identified defensive and risk variables related to emotional labor of hospital nurses. Self-efficacy, social support, leaders' care, and communication are important factors for managing emotional labor of hospital nurses.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제6권1호
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• pp.44-50
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• 2003

If the accelerometers are used in measuring the response, the absolute values of the velocity and displacement are not usually obtainable because their initial values are not accounted for in the integration of the acceleration response. A new dynamic response conversion algorithm of both the time domain and the frequency domain is proposed for the problem in estimating the displacement data by defining the transformed responses. In this algorithm, the displacement response can be obtained from the measured acceleration records by integration without requiring the knowledge of the initial velocity and displacement information. The applicability of the technique is tested by an example problem using the real bridge's superstructure under several cases of moving load. In the response conversion procedure of the frequency domain, the identified response according to the frequency can be estimated by changing over the limits of integration. If the reliability of the identified responses is ensured, it is expected that the proposed method for estimating the impact factor can be useful in the bridge's dynamic test. This method can be useful in those practical cases when the direct measurement of the displacement is difficult as in the dynamic studies of huge structure.

• 한국해양공학회지
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• 제29권5호
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• pp.342-350
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• 2015

A seismic reliability analysis of the jacket-type support structure for an offshore wind turbine was performed. When defining the limit state function using the dynamic response of the support structure, numerous dynamic calculations should be performedin an approach like the FORM (first-order reliability method). This causes a substantial increase in the analysis cost. Therefore, in this paper, a new reliability analysis approach using the static response is used. The dynamic effect of the response is considered by introducing a new parameter called the peak response factor (PRF). The probability distribution of the PRF could be estimated using the peak value of the dynamic response. The probability distribution of the PRF was obtained for a set of ground motions. A numerical example is considered to compare the proposed approach with the conventional static-response-based approach.

• 한국지진공학회논문집
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• 제20권1호
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• pp.55-62
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• 2016

It is important to select an accurate set of ground motions when conducting linear and nonlinear response history analyses of structures. This study proposes a method for selecting ground motions from a ground motion library with response spectra that match the target response spectrum mean, variance and correlation structures. This study also has addressed the determination of an appropriate value for the weight factor of a correlation structure. The proposed method is conceptually simple and straightforward, and does not involve a simulation algorithm. In this method, a desired number of ground motions are sequentially selected from first to last. The proposed method can be also used for selecting ground motions with response spectra that match the conditional spectrum. The accuracy and efficiency of the proposed procedure are verified with numerical examples.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.432-439
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• 2000

According as ground acceleration becomes to exceed gravity acceleration recently, design is impossible or economical efficiency is poor in existing seismic design method. So increase of seismic isolated bridges is currently in progress. However, because base isolation design method is developed in high seismic regions. it may not be compatible in Korea. Therefore, this research has objective to evaluate ductility of pier and response modification factor according to the ductility of pier in seismic isolated bridges and to adapt to seismic characteristics in Korea. For this purpose, nonlinear analysis is accomplished with so many time histories derived from spectral density function compatible with response spectrum described in the design code and base isolation system modeled linear system, bi-linear system, and friction system. Through application of the proposed method, we had result that it may be compatible that response modification factor for the seismic isolated bridges is smaller than half of that for the conventional bridges when natural period of structures exceeds proper level.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.179.5-179
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• 2001

Generally, while PD-type fuzzy controller has good performance in transient period, it has uniform steady state error of response. To improve limitations of PD-type fuzzy controller, we propose a new fuzzy controller to improve the performance of transient response and to eliminate the steady state error of response. In this paper, PD-type fuzzy controller is used a simplified indirect inference method(SIIM). When the SIIM is applied, the proposed method has the capability of the high speed inference and adapting with increasing the number of the fuzzy input variables easily. The outputs of this controller are the output calculated by PD-type fuzzy controller and the accumulated error scaling factor. Here, the accumulated error scaling factor is adjusted by fuzzy rule according to the system state variables. To show the usefulness of the proposed controller, it is applied to 0-type 2nd-order linear system.

• 한국소음진동공학회논문집
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• 제16권11호
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• pp.1132-1139
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• 2006

Non-contact underwater explosions against surface ship could cause extensive equipment damage during wartime service. Thus, the need to develop methods for the design of shock resistant equipment structures and systems was strongly established. In analytical methods, DDAM(Dynamic Design and Analysis Method) and transient repsonse method are used for ship shock design. In this paper, to analyze the characteristics of DDAM, medium weight shock test, DDAM and transient response analysis for missile system equipment are performed.