• 대한조선학회논문집
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• 제32권4호
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• pp.27-37
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• 1995

본 연구에서는 대양을 항행하는 선박의 자동조타 시스템의 정량적 평가, 해석을 위해서 추진 에너지 손실의 관점에서 성능평가지수를 도출하였다. 그 결과 성능평가지수는 침로편차, 타각, 회두각속도의 제곱평균치로써 구성됨을 밝혔고, 아울러 각 제곱평균치의 계수는 선박의 유체역학적 특성에 의해서 결정됨을 알 수 있었다. 또한 성능평가지수는 자동조타 시스템에 불규칙 외란이 입력으로 작용하였을 때, 주파수 응답법과 시뮬레이션 기법에 의해서 정도 높게 계산될 수 있음을 밝혔다. 대표적 해상 상태에서 광석운반선과 소형 어선에 대한 시계산 결과, 주파수 응답법은 작은 외란하에서 시스템이 선형인 경우에는 유용하지만, 비교적 큰 외란하에서 또는 시스템 내부에 비선형 요소가 있는 경우에는 시뮬레이션 기법이 보다 정확하고 유용함을 알 수 있었다.

• The Journal of Korean Physical Therapy
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• 제20권1호
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• pp.17-22
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• 2008

Purpose: This study examined whether or not changes in the static and dynamic balance performance occur during pregnancy. Methods: Fourteen pregnant women and fourteen non-pregnant women volunteered to participate in the study. All subjects were tested for their balance performance on the Chattecx Balance System (Chattanooga Group, Inc., USA) under a two platform condition: stable platform and dynamic platform(forward-backward sliding and tilting). The Chattecx Balance System was measured using the postural sway index, anterior-posterior sway index, and medial-lateral sway index. Results: There was a significant difference in the postural sway index and anterior posterior sway index in the static and dynamic platform condition between the pregnant and non-pregnant women (p<0.05). However, there was no difference in the medial-lateral sway index. Conclusion: The postural sway index and anterior-posterior sway index decreases during pregnancy.

• 동력기계공학회지
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• 제11권3호
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• pp.66-72
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• 2007

This study proposed new method to decide the reference model necessary for design PID controller. In generally, control design problems using the reference model have the following two factors. One factor is that numerical model of the controlled system can be obtained extremely, and the other is that specification for the closed-loop dynamic performance is pure moderate. Therefore, the control design procedure is essentially based on the partial reference model matching which offers a reasonable method to simplify the design and the controller configuration under the controlled system uncertainty. ITAE(Integral of time-multiplied absolute error) performance index and Kitamori method etc. which were used a reference model method had a limit to settling time and rising time of reference model that it arrived to steady state response according to the controlled system. On this study, if it only knew peak time of overshoot and settling time by measurement signal of the controlled system, it can be made the reference model easily. We proposed new method to improve performance index of the reference model superior to existing reference model index and illustrate the numerical simulation results to show the effectiveness of proposed control method design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.134-136
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• 2003

The deregulated electricity market is operated with respect to theory of economical efficiency, and therefore, the system operator requires data with fast contingency ranking for security of the bulk power system. This paper compares the weather dependant probabilistic risk index(PRI) with the system performance index for power flow in the IEEE-RBTS. also, the system performance index for power flow presents the power system stability. The probabilistic risk index can be classified into normal weather and adverse weather. This paper proposes calculation method using the probabilistic risk index in determining contingency ranking requiring for security under the deregulated electricity market.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1024-1027
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• 2005

This paper describes the performance index of mobile robot and development of testbed which is used to evaluate the index. The developed testbed has rectangular structure similar to a living room of home. It is semi-automation testbed system for evaluation of cleaning performance index. This system is composed with scattering and cleaning equipment of test materials, equipment rifting of objects in inner space and sides itself, vision processing system. To be consistent of performance evaluation of cleaning robot, we make use of camera in this system for the sake of measurement of robot s mobility, path and suction quantity.

• 한국정밀공학회지
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• 제12권10호
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• pp.138-148
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• 1995

While Model-based Monitoring systems based on state observer theory have shown much promise in the laboratory, they have not been widely accepted by industry because, inpractice, these systems often have poor performance with respect to accuracy, band-width, reliability(false alarms), and robustness. In this paper, the linitations of the deterministic discrete-time state observer are investigated quantitatively from the machine monitoring viewpoint. The limitations in the transient and steady-state observer performance are quantified as estimation error bounds from which performance indices are selected. Each index represents the conditioning of the corresponding performance. By utilizing matrix norm theory, an unified main index is determined, that dominates all the indices. This index could from the basis for an observer design methodology that should improve the performance of model-based monitoring systems.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.43-49
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• 2006

In this paper, an index for the evaluation of a vehicle intake booming noise and intake sound quality were developed through a correlation analysis and a multiple factor regression analysis of objective measurement and subjective evaluation data. At first, an intake orifice noise was measured at the wide-open throttle test condition. And then, an acoustic transfer function between intake orifice noise and interior noise at the steady state condition was estimated. Simultaneously, subjective evaluation was carried out with a 10-scale score by 8 intake noise and vibration expert evaluators. Next, the correlation analysis between the psychoacoustic parameters derived from the measured data and the subjective evaluation was performed. The most critical factor was determined and the corresponding index for intake booming noise and sound quality are obtained from the multiple factor regression method. And, the optimal design of intake system was studied using the booming noise and the sound quality evaluation index for expectation performance of intake system. Conclusively, the optimal designing parameters of intake system from noise level and sound quality whose point of view were extracted by adapting comparative weighting between the booming noise and sound quality evaluation index, which optimized the process. These work could be represented guideline to system engineers, designers and test engineers about optimization procedure of system performance by considering both of noise level and sound quality.

• 한국건설관리학회논문집
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• 제14권4호
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• pp.118-129
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• 2013

최근 수년간 급증하고 있는 자연재해로 인해 사회적 관심과 함께 연구개발 투자도 지속적으로 증가하고 있다. 하지만, 현재 자연재난분야 연구개발 사업의 성과관리는 기술개발활동 건수, 특허 건수, 논문 건수 등 정량화하기 용이한 지표위주로 구성되어 있으며, 단순히 지표들을 집계하는 차원에 머물고 있어, 해당 분야의 연구개발 특성과 효과를 적절하게 반영하지 못하고 있으며, 연구개발사업의 성과관리 차원에서도 한계를 가지고 있다. 본 연구는 자연재난분야 연구개발 사업에 있어 보다 효율적인 연구개발 사업관리와 연구개발의 당위성 확보를 위한 성과지표 및 성과평가체계를 개발하는 데에 목적이 있다. 이를 위하여 개발한 기존 연구개발 사업 성과지표를 고찰하고 자연재난분야 연구개발 사업이 갖는 고유의 사회 경제적 파급효과의 특성을 고려하여 성과측정지표를 도출하였으며, 이러한 성과지표를 활용하여 사업유형별 특성을 고려한 성과평가체계를 개발하였다. 개발된 성과평가체계의 활용을 통해서 자연재난분야 연구개발 사업에 있어 획일적인 성과평가체계를 개선하고, 사업 특성에 적합한 측정지표항목을 선별적으로 선택하여 평가가 가능한 유연하고, 신뢰성 있는 성과관리가 이루어질 수 있을 것으로 기대된다.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.229-234
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• 2014

In this paper, a design problem of the flywheel energy storage system controller using genetic algorithm (GA) is investigated for a frequency control of the wind diesel hybrid power generation system in an isolated power system. In order to select parameters of the FESS controller, two performance indexes are used. We evaluated a frequency control effect for the wind diesel hybrid power system according to change of the weighted values of a performance index. To verify performance of the FESS controller according to the weighted value of the performance index, the frequency domain analysis using a singular value bode diagram and the dynamic simulations for various weighted values of performance index were performed. To verify control performance of the designed FESS controller, the eigenvalue analysis and the dynamic simulations were performed. The control characteristics with the two designed FESS controller were compared with that of the conventional pitch controller. The simulation results showed that the FESS controller provided better dynamic responses in comparison with the conventional controller.

• 한국공작기계학회논문집
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• 제12권1호
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• pp.92-100
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• 2003

Using a quarter car model, an analytic method for performance estimation of a vehicle suspension system with respect to frequency response, RMS response and performance index is presented. From frequency response function, compromization of response performance to the whole frequency range is verified and from RMS response and performance index, sensitivity of ride md handling characteristics are examined. Using a full car model, sweet area(stable ride area) are determined and performance sensitivity is estimated according to the change of feedback gains. In order to esimate the output sensitivity, response we is displayed using a 3-dimensional contour plot. Design data n suggested for optimal design parameter esimation, which maximize the performance of the given suspension system.