• 재활복지공학회논문지
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• 제10권4호
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• pp.251-257
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• 2016

소아균형검사(Pediatric Balance Scale)는 경증이나 중증의 운동손상을 지닌 학령기 아동에게 사용할 수 있는 균형검사도구이다. 본 연구의 목적은 경직성 양하지 뇌성마비 아동을 대상으로 소아균형검사와 시공간적 보행변수간의 상관관계를 알아보고자 하였다. 소아균형검사는 앉은 자세에서 일어나기, 선 자세에서 앉기, 의자에서 의자로 이동하기, 잡지 않고 서 있기, 한 다리로 서 있기, 제자리에서 $360^{\circ}$ 회전하기, 뒤돌아보기 등 총 14개 항목으로 구성하고, 시공간적 보행변수는 보행속도 및 보폭, 보거리, 보격, 분속수, 양하지 지지 시간을 포함한다. 모든 대상자들은 독립적으로 보행이 가능한 경직성 양하지 뇌성마비 아동이며, 숙련된 소아물리치료사에 의해 소아균형검사와 시공간적 보행변수를 측정하였다. 소아균형검사와 시공간적 보행변수 간의 상관관계를 분석하기 위해 피어슨 상관분석을 사용하였고, 통계학적 유의수준은 0.05로 설정하였다. 소아균형검사의 총점(r=.49~.58)과 세부항목 중 선 자세에서 앉기(r=.48~.60)와 선 자세에서 왼쪽/오른쪽 어깨 뒤로 돌아보기(r=.47~.53), 선 자세에서 바닥에 물건 집어 들기(r=.52~.69)는 보행속도와 보폭, 보거리, 분속수의 각 변수 사이에 모두 유의한 양의 상관관계를 보였으며, 소아균형검사의 대부분 항목이 양하지 지지 시간 간의 매우 높은 음의 상관관계(r=-.48~-.92)를 보여주고 있다. 이는 소아균형검사와 시공간적 보행변수는 높은 상관관계를 가진 것을 관찰 할 수 있었으며, 소아균형검사를 통해 뇌성마비 아동의 보행수준을 예견하는데 유용하게 적용될 것이다.

• Journal of the Korean Statistical Society
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• 제22권2호
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• pp.271-282
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• 1993

Unit root test for temporally aggregated first order autoregressive process is considered. The temporal aggregate of fist order autoregression is an autoregressive moving average of order (1,1) with moving average parameter being function of the autoregressive parameter. One-step Gauss-Newton estimators are proposed and are shown to have the same limiting distribution as the ordinary least squares estimator for unit root when complete observations are available. A Monte-Carlo simulation shows that the temporal aggregation have no effect on the size. The power of the suggested test are nearly the same as the powers of the test based on complete observations.

• 제어로봇시스템학회논문지
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• 제8권12호
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• pp.1056-1060
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• 2002

Model-based tuning rules of the PID controller are proposed incorporating with real-coded genetic algorithms. The optimal parameter sets of the PID controller for step set-point tracking are obtained based on the first-order time delay model and a real-coded genetic algorithm as an optimization tool. As for assessing the performance of the controllers, performance indices(ISE, IAE and ITAE) are adopted. Then tuning rules are derived using the tuned parameter sets, potential rule models and another real-coded genetic algorithm A set of simulation works is carried out to verify the effectiveness of the proposed rules.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.8-13
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• 2004

In the paper, we present a practical design tool which allows us to design PID types and the first order lead/lag compensators incorporating the step response requirements in the stability. For a given plant transfer function of arbitrary order, this program provides a set of controller gains that satisfies both stability and time domain performances. This implies that even if one selects any controller parameters inside the set, the closed loop system with the controller gains meets the design objectives. This tool based on Matlab and GUI will be very useful for control design in the controller parameter space, especially when time domain requirement is given.

• 전자공학회논문지B
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• 제33B권6호
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• pp.45-53
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• 1996

In this paper, the convergence behavior of timing phase when an adaptive partial response equalizer and decision-directed type of a PLL work together in a digital recording channel is described. The phenomena of getting biased in timing phase when the convergence parameter of an adaptive partial response equalizer and timing recovery constant of a PLL are not selected properly is introduced. The phenomena, occurring due to perturbation of timing phase, are analyzed, by computer simulation and the region of ocnvergence for timing phase is discussed. Also, a method to overcome the phenomena using a variable step-size parameter is described.

• Journal of information and communication convergence engineering
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• 제12권4호
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• pp.215-220
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• 2014

We consider quantization optimized for distributed estimation, where a set of sensors at different sites collect measurements on the parameter of interest, quantize them, and transmit the quantized data to a fusion node, which then estimates the parameter. Here, we propose an iterative quantizer design algorithm with a weighted distance rule that allows us to reduce a system-wide metric such as the estimation error by constructing quantization partitions with their optimal weights. We show that the search for the weights, the most expensive computational step in the algorithm, can be conducted in a sequential manner without deviating from convergence, leading to a significant reduction in design complexity. Our experments demonstrate that the proposed algorithm achieves improved performance over traditional quantizer designs. The benefit of the proposed technique is further illustrated by the experiments providing similar estimation performance with much lower complexity as compared to the recently published novel algorithms.

• 동력기계공학회지
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• 제13권4호
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• pp.68-73
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• 2009

The mathematical model has a different response character with the real system because this mathematical model has the modeling errors and the imprecise value of system's parameters. Therefore to find the value of system parameters as possible as near by real value in the model is necessary to design the controlled system. This study concern about the identification method to estimate the parameter for the magnetic bearing system with RCGA(Real Coded Genetic Algorithm). Firstly, we will get the mathematical model from the current amplifier circuit and the magnetic bearing system. Secondly we will get the step response data in this circuit and system. Finally, we will estimate the unknown parameter's value from the data.

• Tribology and Lubricants
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• 제23권3호
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• pp.109-116
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• 2007

A scroll compressor is on the increase in the use for the cooling and ambition machinery because of the advantages about high efficiency, low vibration and low noise. The design of thrust bearing for scroll compressor has depended on the experience. The lubrication considering the squeeze flow was applied for high side shell and low side shell of scroll thrust bearing. This work was based on governing fluid lubrication equation at the general coordinate. It shows the behavior for an orbiting scroll with direct numerical analysis using FDM. This study obtained the theoretical design value by finding load capacity and tilting angle of an orbiting scroll for thrust bearing in a scroll compressor. Especially this work performed the analysis about the design parameter. The program was written using Visual C++ to enhance user to change the design parameter easily. In particular the result value and the pressure profile were displayed as windows in every step for user to understand without difficulty.

• 감성과학
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• 제4권1호
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• pp.61-67
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• 2001

This paper described the effect of subjective approach in case of the human sensibility experiments. The procedure is proceeded subjectively. Human faces are selected as the image presentation media. Pleasant and unpleasant images are selected directly by examiner, And also the image presentation system, which is executed with a computer and has the square-type black box monitor equipment, is manufactured. Images are presented with the step-variation time interval technique. questionnaire test and EEG signal detection data are analyzed. The analysis parameters are a “frequency band integral value” and a “band differential variation ratio”. he results show the high sensibility and fast response. The fact that image presenting repetition alleviates is verified.

• 한국분말재료학회지
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• 제22권5호
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• pp.337-343
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• 2015

Powder compaction is a continually and rapidly evolving technology where it is a highly developed method of manufacturing reliable components. To understand existing mechanisms for compaction, parameter investigation is required. Experimental investigations on powder compaction process, followed by numerical modeling of compaction are presented in this paper. The experimental work explores compression characteristics of soft and hard ductile powder materials. In order to account for deformation, fracture and movement of the particles, a discrete-finite element analysis model is defined to reflect the experimental data and to enable investigations on mechanisms present at the particle level. Effects of important simulation factors and process parameters, such as particle count, time step, particle discretization, and particle size on the powder compaction procedure have been explored.