• 제목/요약/키워드: Process-parameter

검색결과 3,079건 처리시간 0.039초

A Study of the Formation Process of the Fabric Drapes

  • Mizutani, Chiyomi;Baba, Takeichirou;Amano, Toshihiko
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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    • pp.111-111
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    • 2003
  • In our experiments using a new apparatus, the drape formation process was found to consist of three stages, seeds generation, their development and the final stabilizing stages. A new parameter R evaluating the shape of the drape was defined in terms of the vertical projection of the drape. Both drape coefficient and R-parameter are expected to be useful for analyzing the formation process of the fabric drape quantitatively.

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고속카메라를 이용한 저항 점 용접의 너겟 형성 메커니즘 관찰 (Observation of Nugget Formation Mechanism by using High Speed Camera)

  • 조용준;이세헌
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2000년도 특별강연 및 추계학술발표대회 개요집
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    • pp.43-45
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    • 2000
  • Resistance Spot Welding has been one of the important process in the sheet metal fabrication of auto-body industry It is well known that the nugget formation of RSW is the major factor for the strength of the body. A high speed camera was used to consider initial melting and growth of the weld nugget in order to find out the nugget formation mechanism. It was observed that such mechanism had an effect on the dynamic resistance, which was a process parameter of resistance spot welding. Also, the relationship between the mechanism and process parameter was considered for the industrial application.

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PARAMETER ESTIMATION AND SPECTRUM OF FRACTIONAL ARIMA PROCESS

  • Kim, Joo-Mok;Kim, Yun-Kyong
    • Journal of applied mathematics & informatics
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    • 제33권1_2호
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    • pp.203-210
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    • 2015
  • We consider fractional Brownian motion and FARIMA process with Gaussian innovations and show that the suitably scaled distributions of the FARIMA processes converge to fractional Brownian motion in the sense of finite dimensional distributions. We figure out ACF function and estimate the self-similarity parameter H of FARIMA(0, d, 0) by using R/S method. Finally, we display power spectrum density of FARIMA process.

Parameter Design and Analysis for Aluminum Resistance Spot Welding

  • Cho, Yong-Joon;Li, Wei;Hu, S. Jack
    • Journal of Welding and Joining
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    • 제20권2호
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    • pp.102-108
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    • 2002
  • Resistance spot welding of aluminum alloys is based upon Joule heating of the components by passing a large current in a short duration. Since aluminum alloys have the potential to replace steels fur automobile body assemblies, it is important to study the process robustness of aluminum spot welding process. In order to evaluate the effects of process parameters on the weld quality, major process variables and abnormal process conditions were selected and analyzed. A newly developed two-stage, sliding-level experiment was adopted fur effective parameter design and analysis. Suitable ranges of welding current and button diameters were obtained through the experiment. The effects of the factors and their levels on the variation of acceptable welding current were considered in terms of main effects. From the results, it is concluded that any abnormal process condition decreases the suitable current range in the weld lobe curve. Pareto analysis of variance was also introduced to estimate the significant factors on the signal-to-noise (S/N) ratio. Among the six factors studied, fit-up condition is found to be the most significant factor influencing the SM ratio. Using a Pareto diagram, the optimal condition is determined and the SM ratio is significantly improved using the optimal condition.

A Study on the Effects of Parameter Sensitivity on Matched Field Processing

  • Park, Cheolsoo;Woojae Seong;Park, Hang-Soon;Lee, Kyu-Yeul
    • The Journal of the Acoustical Society of Korea
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    • 제20권1E호
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    • pp.31-37
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    • 2001
  • Matched Field Processing (MFP) is a successive process of correcting mismatches between true and assumed parameters by matching the measured acoustic field data with numerically simulated data which we call replica. The MFP is widely used both in geo-acoustic parameter inversions and in source localizations. Whether a certain parameter can be inverted effectively or whether a source can be localized correctly depends on the amount of the influence that a parameter has on the acoustic field during the matching process. Sensitive parameters can be better estimated than the less sensitive ones in MFP. On the contrary, the sensitive parameters affect adversely on the source localization results when they have uncertainties. In this paper, a sensitivity index is defined based upon the field variation resulting from the perturbed parameters. Numerical test results show that the index behaves in accordance with the results of source localization under a mismatched environment and also with the inversion solutions.

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A Note on Relay Feedback Identification Under Static Load Disturbances

  • Kaya, Ibrahim
    • Journal of Electrical Engineering and Technology
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    • 제10권1호
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    • pp.395-400
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    • 2015
  • Obtaining the parameters for PID controllers based on limit cycle information for the process in a relay controlled feedback loop has become an accepted practical procedure. If the form of the plant transfer function is known, exact expressions for the limit cycle frequency and amplitude can be derived so that their measurements, assumed error free, can be used to calculate the true parameter value. In the literature, parameter estimation for an assumed form of the plant transfer function has generally been considered for disturbance free cases, except a recently published work of the author. In this paper additional simulation results are reported on exact parameter estimation from relay autotuning under static load disturbances.

원관내 자성유체의 Rheology 특성에 관한 연구 (A Study on the Rheology Characteristics of Magnetic Fluids in a Circular Pipe)

  • 전언찬;박정우;김태호;김수용
    • 한국기계가공학회지
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    • 제7권2호
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    • pp.38-44
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    • 2008
  • In the present paper, we theoretically analyze the flow of magnetic fluids in a circular pipe with a vertical magnetic field and investigate the magnetic response by the external magnetic field. Theoretical study through the governing equation derived by Siliomis is carried out with numerical analysis by the Gauss Elimination Method. Using polar and magnetic effect parameters, theoretical equations and distributions for the velocity, apparent viscosity as the magnetic response are shown. Especially, in the region of strong magnetic field the specific property is appeared by finding a critical magnetic effect parameter for a polar effect parameter.

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조정점 최적탐색에 의한 Form Parameter 방법에 관한 연구 (A Study on Form Parameter Method by Optimum Vertex Point Search)

  • 김수영;신성철;김덕은
    • 대한조선학회논문집
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    • 제39권4호
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    • pp.60-65
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    • 2002
  • 본 연구는 Form Parameter를 만족하는 선형 생성 과정을 최적화 과정으로 취급하였다. 목적함수는 fairness 기준을 도입하고 설계변수는 B-spline 곡선의 조정점으로 하며 제약조건은 설계자에 의해서 주어지는 기하학적 형상으로 하였다. 최적화 방법은 GA(Genetic Algorithm)와 최적성 기준(optimality criteria)을 병행하였다.

BLDC 전동기 파라메터 산정에 관한 연구 (Study for Calculation of BLDC Motor Parameter)

  • 한경희;백수현;김용;윤신용;김철진
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.134-136
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    • 2001
  • In this paper, using equivalent circuit of BLDC motor in the 30W class, process of modeling the BLDC motor and calculating the parameter is shown. Through run-down-test and measuring back EMF, torque, speed and ampere, parameter that transfer function requires was gotten. In this result, for step response of BLDC motor, comparing the actual result obtained by circuit experiment with the simulation result obtained by substituting this parameter into the transfer function, it was established that process calculating parameters in this study is proper.

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설계 및 공정 변수에 따른 600 V급 IGBT의 전기적 특성 분석 (Analysis of The Electrical Characteristics of Power IGBT According to Design and Process Parameter)

  • 강이구
    • 한국전기전자재료학회논문지
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    • 제29권5호
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    • pp.263-267
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    • 2016
  • In this paper, we analyzed the electrical characteristics of NPT planar and trench gate IGBT after designing these devices according to design and process parameter. To begin with, we have designed NPT planar gate IGBT and carried out simulation with T-CAD. Therefore, we extracted design and process parameter and obtained optimal electrical characteristics. The breakdown voltage was 724 V and The on state voltage drop was 1.746 V. The next was carried out optimal design of trench gate power IGBT. We did this research by same drift thickness and resistivity of planar gate power IGBT. As a result of experiment, we obtain 720 V breakdown voltage, 1.32 V on state voltage drop and 4.077 V threshold voltage. These results were improved performance and fabrication of trench gate power IGBT and planar gate Power IGBT.