• Title/Summary/Keyword: Process Parameter Fluctuation

Search Result 20, Processing Time 0.026 seconds

Multiresponse Optimization Through A New Desirability Function Considering Process Parameter Fluctuation (공정변수의 변동을 고려한 호감도 함수를 통한 다중반응표면 최적화)

  • Kwon Jun-Bum;Lee Jong-Seok;Lee Sang-Ho;Jun Chi-Hyuck;Kim Kwang-Jae
    • Journal of the Korean Operations Research and Management Science Society
    • /
    • v.30 no.1
    • /
    • pp.95-104
    • /
    • 2005
  • A desirability function approach to a multiresponse problem is proposed considering process parameter fluctuation which may amplify the variance of response. It is called POE (propagation of error), which is defined as the standard deviation of the transmitted variability in the response as a function of process parameters. In order to obtain more robust process parameter setting, a new desirability function is proposed by considering POE as well as distance-to-target of response and response variance. The proposed method is illustrated using a rubber product case in Ribeiro et al. (2000).

Multiresponse Optimization through a Loss Function Considering Process Parameter Fluctuation (공정변수의 변동을 고려한 손실함수를 통한 다중반응표면 최적화)

  • Kwon, Jun-Bum;Lee, Jong-Seok;Lee, Sang-Ho;Jun, Chi-Hyuck;Kim, Kwang-Jae
    • Journal of Korean Institute of Industrial Engineers
    • /
    • v.31 no.2
    • /
    • pp.164-172
    • /
    • 2005
  • A loss function approach to a multiresponse problem is considered, when process parameters are regarded as random variables. The variation of each response may be amplified through so called propagation of error (POE), which is defined as the standard deviation of the transmitted variability in the response as a function of process parameters. The forms of POE for each response and for a pair of responses are proposed and they are reflected in our loss function approach to determine the optimal condition. The proposed method is illustrated using a polymer case. The result is compared with the case where parameter fluctuation is not considered.

Multiresponse Optimization Through A New Desirability Function Considering Process Parameter Fluctuation (공정변수의 변동을 고려한 만족도 함수를 통한 다중반응표면 최적화)

  • Gwon Jun-Beom;Lee Jong-Seok;Lee Sang-Ho;Jeon Chi-Hyeok;Kim Gwang-Jae
    • Proceedings of the Korean Operations and Management Science Society Conference
    • /
    • 2004.10a
    • /
    • pp.39-44
    • /
    • 2004
  • A desirability function approach to a multiresponse problem is proposed considering process parameter fluctuation as well as distance-to-target of response and response variance. The variation of process parameters amplifies the variance of responses. It is called POE (propagation of error), which is defined as the standard deviation of the transmitted variability in the response as a function of process parameters. In order to obtain more robust process parameters, this variability should be considered in the optimization problem. The proposed method is illustrated using a rubber product case.

  • PDF

An Analysis of Crack Growth Rate Due to Variation of Fatigue Crack Growth Resistance (피로균열전파저항의 변동성에 의한 균열전파율의 해석)

  • Kim, Seon-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.23 no.7 s.166
    • /
    • pp.1139-1146
    • /
    • 1999
  • Reliability analysis of structures based on fracture mechanics requires knowledge on statistical characteristics of the parameter C and m in the fatigue crack growth law, $da/dN=C({\Delta}K)^m$. The purpose of the present study is to investigate if it is possible to predict fatigue crack growth rate by only the fluctuation of the parameter C. In this study, Paris-Erdogan law is adopted, where the author treat the parameter C as random and m as constant. The fluctuation of crack growth rate is assumed only due to the parameter C. The growth resistance coefficient of material to fatigue crack growth (Z=1/C) was treated as a spatial stochastic process, which varies randomly on the crack path. The theoretical crack growth rates at various stress intensity factor range are discussed. Constant ${\Delta}K$ fatigue crack growth tests were performed on the structural steel, SM45C. The experimental data were analyzed to determine the autocorrelation function and Weibull distributions of the fatigue crack growth resistance. And also, the effect of the parameter m of Paris' law due to variation of fatigue crack growth resistance was discussed.

Computing the Ruin Probability of Lévy Insurance Risk Processes in non-Cramér Models

  • Park, Hyun-Suk
    • Communications for Statistical Applications and Methods
    • /
    • v.17 no.4
    • /
    • pp.483-491
    • /
    • 2010
  • This study provides the explicit computation of the ruin probability of a Le¢vy process on finite time horizon in Theorem 1 with the help of a fluctuation identity. This paper also gives the numerical results of the ruin probability in Variance Gamma(VG) and Normal Inverse Gaussian(NIG) models as illustrations. Besides, the paths of VG and NIG processes are simulated using the same parameter values as in Madan et al. (1998).

STOCHASTIC CHARACTERISTICS OF FATIGUE CRACK GROWTH RESISTANCE OF SM45C STEEL

  • Park, U.H.;Lee, H.W.;Kim, S.J.;Lee, C.R.;Kim, J.H.
    • International Journal of Automotive Technology
    • /
    • v.8 no.5
    • /
    • pp.623-628
    • /
    • 2007
  • Reliability analysis based on fracture mechanics requires knowledge of the on statistical parameters m and C in the fatigue crack growth law $da/dN=C({\Delta}K)^m$. The purpose of the present study is to investigate if it is possible to explain the change of parameter m by the fluctuation of C only. In this study, we apply the Paris-Erdogan law treating the parameter C as random and the parameter m as constant. Fluctuations in crack growth rate are assumed to be dependent only on C. The material resistance to fatigue crack growth(Z=1/C) is treated as a spatially random process, that varies along the crack path. The theoretical crack growth rates at various stress intensity factors are discussed. Additionally, the results of constant ${\Delta}K$ fatigue crack growth tests are reported for the structural steel, SM45C. The experimental data have been analyzed to determine the probability distribution of fatigue crack growth resistanc.

Optimization of Device Process Parameters for GaAs-AlGaAs Multiple Quantum Well Avalanche Photodiodes Using Genetic Algorithms (유전 알고리즘을 이용한 다중 양자 우물 구조의 갈륨비소 광수신소자 공정변수의 최적화)

  • 김의승;오창훈;이서구;이봉용;이상렬;명재민;윤일구
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.14 no.3
    • /
    • pp.241-245
    • /
    • 2001
  • In this paper, we present parameter optimization technique for GaAs/AlGaAs multiple quantum well avalanche photodiodes used for image capture mechanism in high-definition system. Even under flawless environment in semiconductor manufacturing process, random variation in process parameters can bring the fluctuation to device performance. The precise modeling for this variation is thus required for accurate prediction of device performance. The precise modeling for this variation is thus required for accurate prediction of device performance. This paper will first use experimental design and neural networks to model the nonlinear relationship between device process parameters and device performance parameters. The derived model was then put into genetic algorithms to acquire optimized device process parameters. From the optimized technique, we can predict device performance before high-volume manufacturign, and also increase production efficiency.

  • PDF

A Process Analysis for Manufacturing the Sleeve Spring of the Torsional Vibration Damper (비틀림 진동감쇠기용 슬리브 스프링의 제조 공정 해석)

  • Hwang, Beom-Cheol;Bae, Won-Byong;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.26 no.12
    • /
    • pp.94-101
    • /
    • 2009
  • In diesel engines, it is inevitable that the torsional vibration is produced by the fluctuation of engine torque. Therefore, it is necessary to establish preventive measures to diminish the torsional vibration. The sleeve spring type damper is one of the preventive measures for reducing the torsional vibration. In this study, 2-roll bending process was proposed to manufacture sleeve spring; The program to calculate the initial radius including springback effect was developed and the FEA method to analyze elasto-plastic problem was verified through analysis of 90 degree bending process. The elasto-plastic analysis of 2-roll bending process was carried out by the FEA method verified to set a new criterion, and the new process design parameter(contact angle) in the 2-roll bending process was proposed.

Nonlinear analysis of cardiotonic effect of acupuncture treatment on heart rate variability assessed by 24-hour Holter monitoring (침처치의 24시간 심박변이도 영향에 대한 비선형 분석)

  • Oh, Dal-Seok;Lee, Jeon;Kim, Jong-Yeol;Choi, Sun-Mi
    • Korean Journal of Oriental Medicine
    • /
    • v.14 no.1
    • /
    • pp.85-89
    • /
    • 2008
  • This study is to investigate cardiotonic effect of acupuncture on heart rate variability(HRV) analyzed by a nonlinear way(DFA, Detrended Fluctuation Analysis). It was designed as a randomized, single-blind, waiting list-controlled, cross-over study. We assessed heart rate and R-R intervals in Circadian electrocardiography with a Holter monitoring device for twelve hospitalized participants. The compatible analytical program, Zymed, was used for generating the signals of R-R intervals from 24 hour-ECG. In DFA analysis, we produced DFA alpha 1, alpha 2 parameters according to the process of Cygwin module of Linux server. We tested if there was any difference between HRV parameters using SPSS, a statistical package. There was no difference between acupuncture and no treatment group in DFA alpha 2 parameter {95% Confidence Interval (-)0.058 - 0.037, P = .565}. Two group all showed large intra-individual variations. Consequently, acupuncture treatment did not modulate the complexity of HRV in a DFA analysis. This study can be a rationale for acupuncture's properties on cardiovascular and autonomic systems.

  • PDF

EFFECT OF FLOW UNSTEADINESS ON DISPERSION IN NON-NEWTONIAN FLUID IN AN ANNULUS

  • NAGARANI, P.;SEBASTIAN, B.T.
    • Journal of applied mathematics & informatics
    • /
    • v.35 no.3_4
    • /
    • pp.241-260
    • /
    • 2017
  • An analysis is made to study the solute transport in a Casson fluid flow through an annulus in presence of oscillatory flow field and determine how this flow influence the solute dispersion along the annular region. Axial dispersion coefficient and the mean concentration expressions are calculated using the generalized dispersion model. Dispersion coefficient in oscillatory flow is found to be a function of frequency parameter, Schmidt number, and the pressure fluctuation component besides its dependency on yield stress of the fluid, annular gap and time in the case of steady flow. Due to the oscillatory nature of the flow, the dispersion coefficient changes cyclically and the amplitude and magnitude of the dispersion increases initially with time and reaches a non - transient state after a certain critical time. This critical value varies with frequency parameter and independent of the other parameters. It is found that the presence of inner cylinder and increase in the size of the inner cylinder inhibits the dispersion process. This model may be used in understanding the dispersion phenomenon in cardiovascular flows and in particular in catheterized arteries.