• Title/Summary/Keyword: Quantitative technique

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Design of Robust QFT Controller to Damp Low Frequency Oscillations of Power System (전력계통의 저주파 진동 억제를 위한 강인하 QFT 제어기 설계)

  • 정형환;이정필;김상효;정문규;안병철
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.4
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    • pp.833-845
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    • 2001
  • Quantitative Feedback Theory(QFT) has been used to design a robust power system stabilizer(PSS) to improve transient and dynamic stabilities of a power system. This design technique is basically accomplished in frequency domain. The most important feature of QFT is that it is able to deal with the design problem of complicated uncertain plants. A basic idea in QFT design is the translation of closed-loop frequency-domain specifications into Nichols chart domains specifying the allowable range of the nominal open-loop response and then to design a controller by using the gain-phase loop shaping technique. This paper introduces a new algorithm to compute QFT bounds more efficiently. The propose QFT design method ensures a satisfactory performance of the PSS under a wide range of power system operating conditions.

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The Diffusion Tensor Imaging of Muscle Preliminary Results

  • 황문정;박현정;장용민;강덕식
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.167-167
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    • 2001
  • Purpose: To obtain normative human skeletal muscle data and evaluate quantitative diffusion-ten anisotropy information using diffusion-tensor imaging technique. Method: Quantitative extremity muscle diffusion tensor MR images were obtained in 5 healt adults by using turbo STEAM sequence and a combination of tetrahedral and orthogon diffusion gradients. Relative anisotropy(RA) and fractional anisotropy(FA) values we measured in soleus and gastrocnemius muscle in addition to mean ADC value.

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Statistical Estimate Technique of Cut Slope Stability (깎기비탈면 안정성의 통계적 예측기법)

  • Lee, Moon-Se;Shin, Chang-Gun;Jeon, Kuk-Jae;Lee, Seung-Woo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.727-735
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    • 2010
  • The collapse of cut slope near national roads in Korea mostly occurs in every summer when typhoon or localized heavy rain comes. Such collapse brings about a loss of many lives and property and recently the damage is on rapidly increasing trend. Therefore, we may reduce the loss of many lives and property in great deals if we can predict and prepare for the collapse of cut slope. However, it is not easy to predict collapse because there are many factors causing collapse in combination and all they have different levels of contribution. Therefore, this study completed prediction formula by using a statistic technique for quantitative analysis on the interaction of those factors so as to predict the stability of slopes. Consequently, it is judged that effective slope management will be possible by selecting dangerous slopes quantitatively among cut slopes near national roads and by preparing for the collapse in advance.

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Net Analyte Signal-based Quantitative Determination of Fusel Oil in Korean Alcoholic Beverage Using FT-NIR Spectroscopy

  • Lohumi, Santosh;Kandpal, Lalit Mohan;Seo, Young Wook;Cho, Byoung Kwan
    • Journal of Biosystems Engineering
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    • v.41 no.3
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    • pp.208-220
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    • 2016
  • Purpose: Fusel oil is a potent volatile aroma compound found in many alcoholic beverages. At low concentrations, it makes an essential contribution to the flavor and aroma of fermented alcoholic beverages, while at high concentrations, it induced an off-flavor and is thought to cause undesirable side effects. In this work, we introduce Fourier transform near-infrared (FT-NIR) spectroscopy as a rapid and nondestructive technique for the quantitative determination of fusel oil in the Korean alcoholic beverage "soju". Methods: FT-NIR transmittance spectra in the 1000-2500 nm region were collected for 120 soju samples with fusel oil concentrations ranging from 0 to 1400 ppm. The calibration and validation data sets were designed using data from 75 and 45 samples, respectively. The net analyte signal (NAS) was used as a preprocessing method before the application of the partial least-square regression (PLSR) and principal component regression (PCR) methods for predicting fusel oil concentration. A novel variable selection method was adopted to determine the most informative spectral variables to minimize the effect of nonmodeled interferences. Finally, the efficiency of the developed technique was evaluated with two different validation sets. Results: The results revealed that the NAS-PLSR model with selected variables ($R^2_{\upsilon}=0.95$, RMSEV = 100ppm) did not outperform the NAS-PCR model (($R^2_{\upsilon}=0.97$, RMSEV = 7 8.9ppm). In addition, the NAS-PCR shows a better recovery for validation set 2 and a lower relative error for validation set 3 than the NAS-PLSR model. Conclusion: The experimental results indicate that the proposed technique could be an alternative to conventional methods for the quantitative determination of fusel oil in alcoholic beverages and has the potential for use in in-line process control.

A Quantitative Assessment Model for Data Governance (Data Governance 정량평가 모델 개발방법의 제안)

  • Jang, Kyoung-Ae;Kim, Woo-Je
    • Journal of the Korean Operations Research and Management Science Society
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    • v.42 no.1
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    • pp.53-63
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    • 2017
  • Managing the quantitative measurement of the data control activities in enterprise wide is important to secure management of data governance. However, research on data governance is limited to concept definitions and components, and data governance research on evaluation models is lacking. In this study, we developed a model of quantitative assessment for data governance including the assessment area, evaluation index and evaluation matrix. We also, proposed a method of developing the model of quantitative assessment for data governance. For this purpose, we used previous studies and expert opinion analysis such as the Delphi technique, KJ method in this paper. This study contributes to literature by developing a quantitative evaluation model for data governance at the early stage of the study. This paper can be used for the base line data in objective evidence of performance in the companies and agencies of operating data governance.

모호가중점검목록을 이용한 제품의 감성파악에 관한 연구

  • 박경수;정광태
    • Proceedings of the ESK Conference
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    • 1995.04a
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    • pp.25-29
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    • 1995
  • When we design a product, we need to consider human sensibility for the product. In this study, we developed a technique to measure human sensibility for a product. Because human sensibility for a product is very subjective and fuzzy, it is hard to measure easily. To deal with this difficulty effectively, we used fuzzy-weighted checklist to this problem. The fuzzy- weighted checklist presents a fuzzy version of the weighted checklist technique computerized for evaluating or comparing complex system (or subjects). In this technique, we used pairwise comparison to get the relative weights of wensibility factors. Also, we used linguistic ratings to get the scores of sensibility factors for a product. Then, we synthesize the scores of sensi- bility factors to get fuzzy composite score (and linguistic approximation). If there are several alternatives, we can conduct alternative comparison. Finally, we wrote the program of this technique by Quick Basic software. As an example, this technique applied to car. The results show that we can use this technique effectively to the quantitative evaluation of human sensibility

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