• 제목/요약/키워드: Process Length

검색결과 3,183건 처리시간 0.031초

칼만 필터와 뉴럴 네트워크 모델링을 이용한 연속생산공정의 통계적 공정관리 시스템 (Statistical Process Control System for Continuous Flow Processes Using the Kalman Filter and Neural Network′s Modeling)

  • 권상혁;김광섭;왕지남
    • 한국정밀공학회지
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    • 제15권3호
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    • pp.50-60
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    • 1998
  • This paper is concerned with the design of two residual control charts for real-time monitoring of the continuous flow processes. Two different control charts are designed under the situation that observations are correlated each other. Kalman-Filter based model estimation is employed when the process model is known. A black-box approach, based on Back-Propagation Neural Network, is also applied for the design of control chart when there is no prior information of process model. Performance of the designed control charts and traditional control charts is evaluated. Average run length(ARL) is adopted as a criterion for comparison. Experimental results show that the designed control chart using the Neural Network's modeling has shorter ARL than that of the other control charts when process mean is shifted. This means that the designed control chart detects the out-of-control state of the process faster than the others. The designed control chart using the Kalman-Filter based model estimation also has better performance than traditional control chart when process is out-of-control state.

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인공신경망을 통한 사출 성형조건의 최적화 예측 및 특성 선택에 관한 연구 (A study on the prediction of optimized injection molding conditions and the feature selection using the Artificial Neural Network(ANN))

  • 양동철;김종선
    • Design & Manufacturing
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    • 제16권3호
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    • pp.50-57
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    • 2022
  • The qualities of the products produced by injection molding are strongly influenced by the process variables of the injection molding machine set by the engineer. It is very difficult to predict the qualities of the injection molded product considering the stochastic nature of the manufacturing process, since the processing conditions have a complex impact on the quality of the injection molded product. It is recognized that the artificial neural network(ANN) is capable of mapping the intricate relationship between the input and output variables very accurately, therefore, many studies are being conducted to predict the relationship between the results of the product and the process variables using ANN. However in the condition of a small number of data sets, the predicting performance and robustness of the ANN model could be reduced due to too many input variables. In the present study, the ANN model that predicts the length of the injection molded product for multiple combinations of process variables was developed. And the accuracy of each ANN model was compared for 8 process variables and 4 important process inputs that were determined by the feature selection. Based on the comparison, it was verified that the performance of the ANN model increased when only 4 important variables were applied.

Large deflections of spatial variable-arc-length elastica under terminal forces

  • Phungpaingam, Boonchai;Athisakul, Chainarong;Chucheepsakul, Somchai
    • Structural Engineering and Mechanics
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    • 제32권4호
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    • pp.501-516
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    • 2009
  • This paper aims to study the large deflections of variable-arc-length elastica subjected to the terminal forces (e.g., axial force and torque). Based on Kirchhoff's rod theory and with help of Euler parameters, the set of nonlinear governing differential equations which free from the effect of singularity are established together with boundary conditions. The system of nonlinear differential equations is solved by using the shooting method with high accuracy integrator, seventh-eighth order Runge-Kutta with adaptive step-size scheme. The error norm of end conditions is minimized within the prescribed tolerance ($10^{-5}$). The behavior of VAL elastica is studied by two processes. One is obtained by applying slackening first. After that keeping the slackening as a constant and then the twist angle is varied in subsequent order. The other process is performed by reversing the sequence of loading in the first process. The results are interpreted by observing the load-deflection diagram and the stability properties are predicted via fold rule. From the results, there are many interesting aspects such as snap-through phenomenon, secondary bifurcation point, loop formation, equilibrium configurations and effect of variable-arc-length to behavior of elastica.

크롤러 크레인의 붐 길이 선회각도에 의한 롤러 하중 해석 (Analysis of Roller Load by Boom Length and Rotation Angle of a Crawler Crane)

  • 이득기;강정호;김태현;오철규;김종민;김종명
    • 한국기계가공학회지
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    • 제20권3호
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    • pp.83-91
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    • 2021
  • A crawler crane, which consists of a lattice boom, a driving system, and a movable vehicle, is widely used on construction sites. The crawler crane often traverses rough terrain at these sites; as a result, an overload limiter needs to be installed on the crane to prevent it from overturning and breaking. In this paper, we studied the distributed load change in relation to boom length and the angle of rotation of the roller that comes in direct contact with the grounded track shoe. First, we developed a 3D model of a crawler crane and meshed it for finite elements. Then, we performed finite element analysis to derive the load on the roller. Finally, we graphed and examined the roller distributed load data of the case according to boom length and rotation angle. By detecting the load on the roller of the crawler crane, we can predict the potential for the crane to overturn before it happens.

적출 유두근에서 근육길이에 따른 계단현상 및 칼슘 수축력의 변화 (Length-dependent Staircase Phenomenon and Calcium Inotropisn in Isolated Rabbit Papillary Muscle)

  • 김기환;엄융의;남기용
    • The Korean Journal of Physiology
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    • 제14권2호
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    • pp.7-16
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    • 1980
  • The effects of various inotropic interventions on the shape of the steady state length tension relation and the length-dependent activation process in cardiac muscle were studied. The influence of inotropic interventions upon the action potential was also observed. The range of varying muscle length was from the optimal length$(l_{max})$, where the active tension production is maximal, to 0.85 $l_{max}$. Changes in stimulus frequency or in external bathing Ca concentration constituted the inotropic interventions in this experiment. The papillary muscles were isolated from the rabbit right ventricles and perfused with $HCO-_3\;-buffered$ normal Tyrode solution which was aerated with $3%\;CO_2-97%\;O_2$ mixed gas and kept at $35^{\circ}C$. Resting Passive tension at $l_{max}$ was approximately 30% of the total tension and appeared from the muscle length of 0.90 $l_{max}$. The effect of stimulus frequency on the steady state level of developed tension was: As the stimulus frequency was increased from 0.1 to 0.5 Hz, there was little change in developed tension. As the frequency was increased further, to a value of about 3 Hz, tension increased steeply. Further increase of the frequency to 5 Hz had little additional effect on the developed tension. The length-tension curves for isometric peak tension became more steeper with the degree of potentiation by inotropic interventions. The relative steepness of the normalized length-tension curves where tension production was expressed as a percentage of maximal tension developed at $l_{max}$, varied inversely with the level of inotropic state and these curves were not superimposable one another. Thus at the stimulus frequency of 2 Hz or at the external Ca concentration of 8 mM, the relative decline in the developed tension for a given change in muscle length was considerably less than the decline observed at the frequency of 0.5 Hz or at the concentration of 2 mM Ca. Action potential duration was prolonged significantly as the frequency increased from 0.2 to 2 Hz, and this change in action potential duration was not observable on the changes in muscle length. There was a tendency of the hyperpolarization of membrane potential when the muscle length was shortened from $l_{max}$ to 0.95 $l_{max}$. These results support the hypothesis that there is a length-dependence of the activation process.

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닥나무 인피섬유의 절단장이 펄프화 및 한지의 물성에 미치는 영향(제1보) - 국산 닥 백피의 특성 - (The Effects of the Cutting Length of Paper Mulberry Bast Fiber on Pulping and Hanji Properties(I) - White bast of Korea grown paper mulberry -)

  • 임강혁;최태호
    • 펄프종이기술
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    • 제40권2호
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    • pp.57-64
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    • 2008
  • In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

조합하중이 작용하는 복합적층 패널의 최소중량화설계 (Minimum Weight Design of Laminated Composite Panel under Combined Loading)

  • 이종선
    • 한국공작기계학회논문집
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    • 제15권1호
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    • pp.95-101
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    • 2006
  • Minimum weight design of laminated composite panel under combined loading was studied using linear and nonlinear deformation theories and by closed-form analysis and finite difference energy methods. Various buckling load factors are obatined for laminated composite panels with rectangular type longitudinal stiffeners and various longitudinal length to radius ratios, which are made from Carbon/Epoxy USNl25 prepreg and are simply-supported on four edges under combined loading, and then for them, minimum weight design analyses are carried out by the nonlinear search optimizer, ADS. This minimum weight design analyses are constructed with various process such as the simple design process, test simulation process and sensitivity analysis. Subseguently, the buckling mode shapes are obtained by buckling and minimum weight analyses.

신소재 복합재 철도차량 차체 제작기술 및 구조강도 평가 (Evaluation of manufacturing process and structural strength for the composites carbody)

  • 정종철;이상진;조세현;서승일;김천곤
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2005년도 춘계학술대회 논문집
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    • pp.403-408
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    • 2005
  • This research presents the manufacturing process and the structural strength assessment for the hybrid composite carbody. In this study, the manufacturing process for carbody with length of 23m was explained. The composite carbody was fabricated as one body using autoclave with length of 30m and 5m diameter. The structural behavior of the carbody under the 3-point supporting and the natural frequency were evaluated as well. In addition, the test results were compared with the numerical one. From the tests, the structural strength of the hybrid composite carbody was assessed.

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2중 2 런규칙을 사용한 공정이상 감지방법의 경제성 분석 (Economic Analysis for Detection of Out-of-Control of Process Using 2 of 2 Runs Rules)

  • 김영복;홍정식;이창훈
    • 대한산업공학회지
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    • 제34권3호
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    • pp.308-317
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    • 2008
  • This research investigates economic characteristics of 2 of 2 runs rules under the Shewhart $\bar{X}$ control chart scheme. A Markov chain approach is employed in order to calculate the in-control average run length (ARL) and the average length of analysis cycle. States of the process are defined according to the process conditions at sampling time and transition probabilities are derived from the state definitions. A steady state cost function is constructed based on the Lorezen and Vance(1986) model. Numerical examples show that 2 of 2 runs rules are economically superior to the Shewhart $\bar{X}$ chart in many cases.

Introducing hydrostatic extrusion process for long-length processing of Bi-2223 superconducting tape

  • 정재훈;유재무;고재웅;강신철;김해두
    • Progress in Superconductivity
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    • 제3권2호
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    • pp.193-197
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    • 2002
  • There are many problems in wire fabrication of long length Bi-2223 superconductor by using conventional extrusion method. They are mainly due to high surface resistance and inhomogeneous distribution of inner stress. Hydrostatic extrusion process will not only decrease the extrusion pressure but also enhance homogeneous deformation of material by reducing friction force between billet and container Hydrostatic extrusion method is considered to be useful fur fabrication of the homogeneous wire with high density. In this paper, hydrostatic extrusion process is introduced to fabricate Bi-2223 superconducting tape, and also discussed are the interface homogeneity and microstructural aspects of extruded BSCCO/Ag billet.

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