• Title/Summary/Keyword: process control

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A Study on Prototype of Just In Time Production Management System (적시생산 관리시스템에 관한 연구 - 철근공사를 중심으로 -)

  • Lee, Kyoo-Hyun;Choi, In-Sung
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.4 s.18
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    • pp.153-164
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    • 2005
  • This study aims at establishing JIT production management system to enable manage the resources input into from procurement through construction based on correct identification of the process, an analysis on the amount of input materials and information sharing. This study has focused on the process control and working process of rebar work in domestic apartment house construction where the overall scope of Process from the planning phase to the construction phase has been analyzed in this study. Also construction phase was selected for the application of a sample case. A basic model for JIT production was generated with these processes. Furthermore A questionnaire and the on-site survey with process, checklist and control data were prepared and performed for the application of JIT production management model into rebar work. The governing scopes of JIT production management system include process management, material management, yard loading and moving management and inventory control, and the operation of each control item

To study of optimal subgroup size for estimating variance on autocorrelated small samples (소표본 자기상관 자료의 분산 추정을 위한 최적 부분군 크기에 대한 연구)

  • Lee, Jong-Seon;Lee, Jae-Jun;Bae, Soon-Hee
    • Proceedings of the Korean Society for Quality Management Conference
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    • 2007.04a
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    • pp.302-309
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    • 2007
  • To conduct statistical process control needs the assumption that the process data are independent. However, most of chemical processes, like a semi-conduct processes do not satisfy the assumption because of autocorrelation. It causes abnormal out of control signal in the process control and misleading process capability. In this study, we introduce that Shore's method to solve the problem and to find the optimal subgroup size to estimate variance for AR(l) model. Especially, we focus on finding an actual subgroup size for small samples using simulation. It may be very useful for statistical process control to analyze process capability and to make a Shewhart chart properly.

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A study on the Flexible Disk Grinding Process with Variable Control Stages (절삭속도제어 구간에 따른 유연성 디스크 연삭가공에 관한 연구)

  • 신관수
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.1
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    • pp.81-87
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    • 2000
  • A variable cutting speed control model was developed to be implemented for the flexible disk grinding process Control algorithm was based on the error referred by the discrepancy between current disk angle and intended one that are pro-posed to produce desired resulting depth of cut. Controller was implemented in two different aspect One was to initiate the control law from the beginning while the other was to activate as soon as the disk start to produce ground surface i.e. The beginning of the between edges stage. Several performance analysis were conducted comparing various process parameters such as cutting force disk angle depth of cut and disk speed with respect to process transition time Tentative results revealed that controller implemented from the earlier stages of the process showed better performance than the other revealed that controller implemented from the earlier stages of the process showed better performance that the other.

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Rheological perspectives of industrial coating process

  • Kim, Sun-Hyung;Kim, Jae-Hong;Ahn, Kyung-Hyun;Lee, Seung-Jong
    • Korea-Australia Rheology Journal
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    • v.21 no.2
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    • pp.83-89
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    • 2009
  • Coating process plays an important role in information technology such as display, battery, chip manufacturing and so on. However, due to complexity of coating material and fast deformation of the coating flow, the process is hard to control and it is difficult to maintain the desired quality of the products. Moreover, it is hard to measure the coating process because of severe processing conditions such as high drying temperature, high deformation coating flow, and sensitivity to the processing variables etc. In this article, the coating process is to be re-illuminated from the rheological perspectives. The practical approach to analyze and quantify the coating process is discussed with respect to coating materials, coating flow and drying process. The ideas on the rheology control of coating materials, pressure and wet thickness control in patch coating process, and stress measurement during drying process will be discussed.

Malfunction detection in plasma etching process using EPD signal trace (EPD 신호검출에 의한 플라즈마식각공정의 이상검출)

  • 이종민;차상엽;최순혁;우광방
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.1360-1363
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    • 1996
  • EPD(End Point Detection) is used to decide etching degree of layer which must be removed at wafer etching process in plasma etching process which is one of the most important process in semiconductor manufacturing. In this thesis, the method which detects malfunction of etching process in real-time will be discussed. Several EPD signal traces are collected in normal plasma etching condition and used as reference EPD signal traces. Critical points can be detected by applying differentiation and zero-crossing techniques to reference EPD signal. Mean and standard deviation of critical parameters which is memorized from reference EPD signal are calculated and these determine the lower and higher limit of control chart. And by applying statical control chart to EPD signals which are collected in real etching process malfunctions of process are detected in real-time. By means of applying this method to the real etching process we prove our method can accurately detect the malfunction of etching process and can compensate disadvantage of current industrial method.

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A Study on the Plan Establishing Process Data System for the Process Plan of Construction Works (건설공사의 공정계획을 위한 공정정보 시스템 구축에 관한 연구)

  • 안효수;권춘안
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2001.11a
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    • pp.142-147
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    • 2001
  • Recently, as the field of construction industrial is enlarged and the blanket control system is formed, the process plan considered from initial process formation to construction cost must be systematic and rational. So we have to propose and compose the new process formation system that divides the intention decisive property of construction data, its relationship and the data property according to process definitely and can express and control easily the public ownership of construction data and network process under the peculation control. So this study decides the field formation and construction data of the work according to the ordering and contract way to establish the process data system for the process plan, shows that the lot theory is necessary to form the economical construction field and proposes that the integrated formation system of construction data that is made by code system must be established.

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Development of Levitation Control for High Accuracy Magnetic Levitation Transport System (초정밀 자기부상 이송장치의 부상제어기 개발)

  • Ha, Chang-Wan;Kim, Chang-Hyun;Lim, Jaewon
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.7
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    • pp.557-561
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    • 2016
  • Recently, in the manufacturing process of flat panel displays, mass production methods of inline system has been emerged. In particular the next generation OLED display manufacturing process, horizontal inline evaporation process has been tried. It is important for the success of OLED inline evaporation process to develop a magnetic levitation transport system capable of transferring a carrier equipped with a mother glass with high accuracy without any physical contact along the rail under vacuum condition. In the case of existing wheel-based transfer system, it is not suitable for OLED evaporation process requiring high cleanliness. On the other hand, the magnetic levitation transport system has an advantage that it does not generate any dust and it is possible to achieve high-precision control because there are not non-linear factors such as friction force. In this paper, we introduce the high-precision magnetic levitation transport system, which is currently under development, for OLED evaporation process.

A Grounded Theory Approach to the Adjustment Process of the Institutionalized Elderly : The Control of Reluctance (시설노인의 적응과정에 대한 근거이론적 접근 : 거부감 다스리기)

  • 이가언
    • Journal of Korean Academy of Nursing
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    • v.32 no.5
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    • pp.624-632
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    • 2002
  • The number of residents in elderly institution has been increasing due to the change of the family support system. This study was focused on understanding the process of adjustment of the institutionalized elderly using the Grounded Theory approach. Method: There were seven participants, 4 men and 3 women living in 3 different elderly facilities. The data was collected through in-depth interviews and participant observation from June 20, 1999 to January 10, 2000 and analyzed by the Strauss and Corbin's analysis method. Result: 125 concepts were found and grouped into 30 sub-categories and then grouped into 13 categories. These categories are , , , , , , , , , , , and , which were synthesized into the process of adjustment. being the core category. The adjustment process of the facility elderly consisted of : 1. expressive phase of 'reluctance' 2. control phase of 'reluctance' 3. latent phase of 'reluctance' Conclusion: This study offers better understandings on the adjustment process of the institutionalized elderly and provides more appropriate nursing care to the New Comers of these facilities.

A readjustment procedure in the multivariate integrated process control (다변량 통합공정관리에서 재수정 절차)

  • Cho, Gyo-Young;Park, Jong-Suk
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.6
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    • pp.1123-1135
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    • 2011
  • This paper considers the multivariate integrated process control procedure for detecting special causes in a multivariate IMA(1, 1) process. When the multivariate control chart signals, the special cause will be detected and eliminated from the process. However, when the elimination of the special cause costs high or is not practically possible, an alternative action is to readjust the process with approximately modified adjustment scheme. In this paper, we propose the readjustment procedure after having a true signal, and show that the use of the readjustment can reduce the deviation of a process from the target.

Multivariate Control Charts for Autocorrelated Process

  • Cho, Gyo-Young;Park, Mi-Ra
    • Journal of the Korean Data and Information Science Society
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    • v.14 no.2
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    • pp.289-301
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    • 2003
  • In this paper, we propose Shewhart control chart and EWMA control chart using the autocorrelated data which are common in chemical and process industries and lead to increase the number of false alarms when conventional control charts are applied. The effect of autocorrelated data is modeled as a autoregressive process, and canonical analysis is used to reduce the dimensionality of the data set and find the canonical variables that explain as much of the data variation as possible. Charting statistics are constructed based on the residual vectors from the canonical variables which are uncorrelated over time, and the control charts for these statistics can attenuate the autocorrelation in the process data. The charting procedures are illustrated with a numerical example and simulation is conducted to investigate the performances of the proposed control charts.

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