• Title/Summary/Keyword: Performance measurement index

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Automatic Visual Feature Extraction And Measurement of Mushroom (Lentinus Edodes L.)

  • Heon-Hwang;Lee, C.H.;Lee, Y.K.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.1230-1242
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    • 1993
  • In a case of mushroom (Lentinus Edodes L.) , visual features are crucial for grading and the quantitative evaluation of the growth state. The extracted quantitative visual features can be used as a performance index for the drying process control or used for the automatic sorting and grading task. First, primary external features of the front and back sides of mushroom were analyzed. And computer vision based algorithm were developed for the extraction and measurement of those features. An automatic thresholding algorithm , which is the combined type of the window extension and maximum depth finding was developed. Freeman's chain coding was modified by gradually expanding the mask size from 3X3 to 9X9 to preserve the boundary connectivity. According to the side of mushroom determined from the automatic recognition algorithm size thickness, overall shape, and skin texture such as pattern, color (lightness) ,membrane state, and crack were quantified and measured. A portion of t e stalk was also identified and automatically removed , while reconstructing a new boundary using the Overhauser curve formulation . Algorithms applied and developed were coded using MS_C language Ver, 6.0, PC VISION Plus library functions, and VGA graphic function as a menu driven way.

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Effect of a coconut oil intervention on the periodontal health of smokers

  • Yun-Jeong Kim;Jin-Ju Yang;Seon-Yeong Kim;Ah-Young Choi;Woo-Jung Noh
    • Journal of Korean society of Dental Hygiene
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    • v.23 no.1
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    • pp.25-31
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    • 2023
  • Objectives: This study performed a comparative evaluation of the effects of oil pulling on the periodontal health of smokers. Methods: The experimental (15 subjects) and control (15 subjects) were provided coconut oil and distilled water, respectively. We evaluated the pocket depth (≥4 mm), bleeding on exploration, and Patient Hygiene Performance (PHP) index in both groups following the interventions. Clinical parameters were assessed at baseline, after 4 weeks, and after 8 weeks. Dry mouth and oral health-related quality of life were evaluated at baseline and after 8 weeks. Results: Bleeding on exploring in the control group decreased from 26.17 to 18.33 and from 26.07 to 12.53 in the experimental group (p=0.030), with significant differences in measurement time (p<0.001), and the interaction between group and measurement time (p=0.002). The PHP index in the control group decreased from 24.50 to 16.17 and from 24.00 to 9.83 in the experimental group (p=0.027), with significant differences in measurement time (p<0.001), and the interaction between group and measurement time (p=0.001). Furthermore, the experimental group showed a significant decrease in dry mouth (p<0.001) and a significant increase in oral health-related quality of life (p=0.025). Conclusions: The coconut oil intervention positively affected the periodontal health of smokers.

Vibration Transmissibility Analysis and Measurement of Automotive Clutch Spring Dampers (차량 클러치 스프링 댐퍼의 진동 전달률 해석 및 측정)

  • Jang, Jae-Duk;Kim, Gi-Woo;Kim, Won-Jin
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.10
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    • pp.902-908
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    • 2013
  • The input torque ripple induced by combustion engines is a significant source of NVH(noise, vibration and harshness) problem in automotive transmissions. Because this torque fluctuation is primarily transmitted to the input shaft of automotive powertrains(e.g., automatic transmissions) when the lock-up clutches are closed, a torsional damper with helical springs is generally inserted between engine and transmissions to isolate the input vibratory energy, which is essential for the passenger comfort. The torsional vibration isolator exhibits frequency ranges in which there is low vibration transmissibility. However, the isolation performance is currently evaluated through the static torsional spring characteristics. In this study, the transmissibility of torsional spring dampers, essential dynamic performance index for vibration isolator, is first experimentally evaluated.

An Extended Robust $H_{\infty}$ Filter for Nonlinear Constrained Uncertain System

  • Seo, Jae-Won;Yu, Myeong-Jong;Park, Chan-Gook;Lee, Jang-Gyu
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.565-569
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    • 2003
  • In this paper, a robust filter is proposed to effectively estimate the system states in the case where system model uncertainties as well as disturbances are present. The proposed robust filter is constructed based on the linear approximation methods for a general nonlinear uncertain system with an integral quadratic constraint. We also derive the important characteristic of the proposed filter, a modified $H_{\infty}$ performance index. Analysis results show that the proposed filter has robustness against disturbances, such as process and measurement noises, and against parameter uncertainties. Simulation results show that the proposed filter effectively improves the performance.

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Design of the Well-Conditioned Observer Using the Non-Normality Measure (비정규지표를 이용한 Well-Conditioned 관측기 설계)

  • Jung, Jong-Chul;Huh, Kun-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.6
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    • pp.1114-1119
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    • 2002
  • In this paper, the well-conditioned observer is designed to be insensitive to the ill-conditioning factors in transient and steady-state observer performance. A condition number based on 12-norm of the eigenvector matrix of the observer matrix has been proposed on a principal index in the observer performance. For the well-conditioned observer design, the non-normality measure and the observability condition of the observer matrix are utilized. The two constraints are specified into observer gain boundary region that guarantees a small condition number and a stable observer. The observer gain selected in this region guarantees a well-conditioned and observable property. In this study, this method is applied to the Luenberger observer and Kalman filters for small order systems. In designing Kalman filters, the ratio of the process noise covariance to the measurement noise covariance is a design parameter and its effect on the condition number is investigated.

Performance of Different Sensors for Monitoring of the Vibration Generated during Thermosonic Non-destructive Testing

  • Kang, Bu-Byoung
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.2
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    • pp.111-117
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    • 2011
  • Vibration monitoring is required for reliable thermosonic testing to decide whether sufficient vibration is achieved in each test for the detection of cracks. From a practical point of view, a cheaper and convenient monitoring method is better for the application to real tests. Therefore, the performance of different sensors for vibration monitoring was investigated and compared in this study to find a convenient and acceptable measurement method for thermosonics. Velocity measured by a laser vibrometer and strain provide an equivalent HI when measured at the same position. The microphone can provide a cheaper vibration monitoring device than the laser and the heating index calculated by a microphone signal shows similar characteristics to that calculated from velocity measured by the laser vibrometer. The microphone frequency response shows that it underestimates high frequency components but it is applicable to practical tests because it gives a conservative value of HI.

Design of the Well-Conditioned Observer Using the Non-normality Measure (비정규지표를 이용한 Well-Conditioned 관측기 설계)

  • 정종철;허건수
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.10a
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    • pp.313-318
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    • 2001
  • In this paper, the well-conditioned observer is designed to be insensitive to the ill-conditioning factors in transient and steady-state observer performance. A condition number based on $L_2-norm$ of the eigenvector matrix of the observer matrix has been proposed on a principal index in the observer performance. For the well-conditioned observer design, the non-normality measure and the observability condition of the observer matrix are utilized. The two constraints are specified into observer gain boundary region that guarantees a small condition number and a stable observer. The observer gain selected in this region guarantees a well-conditioned and observable property. In this study, this method is applied to the Luenberger observer and Kalman filters. In designing Kalman filters for small order systems, the ratio of the process noise covariance to the measurement noise covariance is a design parameter and its effect on the condition number is investigated.

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Robust Observer Design for Multi-Output Systems using Eigenstructure (고유구조를 이용한 다중출력 시스템의 강인한 관측기 설계)

  • 허건수;남준철
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.39-44
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    • 2003
  • It was shown that the robustness of deterministic observers with respect to modeling errors, measurement bias and round-off errors can be represented by a single performance index the condition number of the observer eigenvector matrix. In this paper, a robust observer for multi-output systems is designed using the left eigenstructure assignment, where the observer gain can not be determined uniquely with respect to the desired observer poles. Utilizing the eigenstructuer assignment for the robustness of the observer, the desired eigenvector matrix is selected to achieve the observer eigenvector matrix with the small condition number. The performance of the designed robust observer is evaluated in a spindle-drive simulation example where the load speed to be estimated based on the measured signals.

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The Dynamic Effects of Globalization on the Firm Performance: A Study on Korea Maritime and Fishery Companies

  • Donghyun Lee;Heedae Park;Joongsan Ko
    • Journal of Korea Trade
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    • v.26 no.7
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    • pp.127-144
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    • 2022
  • Purpose - This study aimed to analyze the dynamic effects of progress in globalization on firm performance by employing individual companies' financial statement datasets. Design/methodology - The analysis leveraged the variables of operating revenue (OPRE) and pre-tax profit and loss (PLBT) as measurement variables for firm performance over 2011-2019. As a proxy variable for globalization, the trade index, a subordinate indicator of the KOF Globalization Index, was used. Through panel regression analysis, the relationship among those variables was ascertained, and the local projection (LP) method was subsequently utilized to identify dynamic effects. A subsample analysis was further performed by classifying companies based on their sizes and industries to determine the differential effects of globalization on each group. Findings - The panel regression analysis derived positive effects of an increasing degree of globalization on OPRE of Korea maritime and fishery firms. However, the impulse response functions, obtained from the LP, showed that in the short run, globalization affects PLBT negatively but in the long run, it gradually converted into a positive effect. In addition, according to the subsample analysis based on company size, the effects of globalization on OPRE became greater as each company became larger. Moreover, the industry-based analysis showed heterogeneous effects, depending on the industries in which the maritime and fishery companies operated. Originality/value - The analysis of the dynamic effects of globalization on firm performance, which revealed that the effects vary depending on the time points, is the important contribution of this study. The results also suggest that the effects of globalization vary depending on the company size and industry.

Model Predictive Control of the Melt Index in High-Density Polyethylene(HDPE) Process (고밀도 폴리에틸렌 공정의 Melt Index 모델예측제어에 관한 연구)

  • Lee, Eun Ho;Kim, Tae Young;Yeo, Yeong Koo
    • Korean Chemical Engineering Research
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    • v.46 no.6
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    • pp.1043-1051
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    • 2008
  • In polyolefin processes melt index (MI) is the most important controlled variable indicating product quality. Because of the difficulty in the on-line measurement of MI, a lot of MI estimation and correlation methods have been proposed. In this work a new dynamic MI estimation scheme is developed based on system identification techniques. The empirical MI estimation equation proposed in the present study is derived from the $1^{st}$-order dynamic models. Effectiveness of the present estimation scheme was illustrated by numerical simulations based on plant operation data including grade change operations in high density polyethylene (HDPE) processes. From the comparisons with other estimation methods it was found that the proposed estimation scheme showed better performance in MI predictions. Using the model predictive control method based on the present dynamic MI estimation model, MI values are estimated and compared with those of MI setpoints. From the numerical simulation of the proposed control system, it was found that significant reduction of transition time and the amount of off-spec during grade changes were achieved.