• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.4
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• pp.1-14
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• 2005

We propose a VSSI-CRL(Variable Sampling Size and Samplina Interval-Conforming Run length) synthetic control chart in order to improve the statistical characteristics of both the VSSI chart and the CRL synthetic chart. The VSSI-CRL chart utilizes VSSI sampling scheme, but it produces a signal only when the CRI is less than a given limit. An algorithm for calculating the ARL(Average Run length) and ATS(Average Time to Signal) of the VSSI-CRL chart is developed by employing Markov chain method. We present some lemmas for describing the statistical characteristics of the VSSI-CRL chart under in-control state. A procedure for designing the VSSI-CRL chart is proposed based on the lemmas. Extensive comparative studios show that the VSSI-CRL chart is superior to the CRL synthetic chart or the VSSI chart in general, and is comparable to the EWMA chart in ATS performance.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1720-1728
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• 2018

This paper proposes a novel soft starting algorithm by using PWM inverter technique to control an amplitude of the motor starting current at a single-phase induction motor (SPIM). Traditional SPIM starting methods such as a Split-Phase, Capacitor-Start, Permanent-Split Capacitor (PSC), Capacitor-Start Capacitor-Run (CSCR), basically cannot control the magnitude of starting current due to the fixed system structures. Therefore, in this paper, a soft starting algorithm based on a proportional resonant (PR) control with a variable and constant frequency is proposed to reduce the inrush current and starting up time. In addition, a transition algorithm for operation modes is devised to generate a constant voltage and constant frequency (CVCF). The validity and effectiveness of the proposed soft starting method and transition algorithm are verified through experimental results.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.111-119
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• 1987

Scale effects of stability, run-up, run-down and reflection of layered coastal structures are investigated through the experiments with 7 kinds of hydraulic scale models. The occurrence mechanism and the control method of scale effects are also discussed. As a result, it is found that the similarity of permeability of inner layers plays an important role in the occurrence of scale effects, which has been neglected in the most of conventional model tests. To assure the best scale effects for permeable coastal structures, control of Reynolds numbers of the porous media flow in each layer is recommended. It is also found that Reynolds numbers in revetment, filter, and core layer must be greater than $2{\times}10^4$, $3{\times}10^3$, and $1{\times}10^3$, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2606-2611
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• 2003

Comprehensive study on the control system design for a RTP process has been conducted. The purpose of the control system is to maintain maximum temperature uniformity across the silicon wafer achieving precise tracking for various reference trajectories. The study has been carried out in two stages: thermal balance modeling on the basis of a semi-empirical radiation model, and optimal iterative learning controller design on the basis of a linear state space model. First, we found through steady state radiation modeling that the fourth power of wafer temperatures, lamp powers, and the fourth power of chamber wall temperature are related by an emissivity-independent linear equation. Next, for control of the MIMO system, a state space modeland LQG-based two-stage batch control technique was derived and employed to reduce the heavy computational demand in the original two-stage batch control technique. By accommodating the first result, a linear state space model for the controller design was identified between the lamp powers and the fourth power of wafer temperatures as inputs and outputs, respectively. The control system was applied to an experimental RTP equipment. As a consequence, great uniformity improvement could be attained over the entire time horizon compared to the original multi-loop PID control. In addition, controller implementation was standardized and facilitated by completely eliminating the tedious and lengthy control tuning trial.

• The Korean Journal of Applied Statistics
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• v.31 no.4
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• pp.485-495
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• 2018

The CCC-r chart is more effective than traditional attribute control charts for monitoring high-quality processes. In-control process parameters are typically unknown and should be estimated when implementing a CCC-r chart. Phase II control chart performance can deteriorate due to the effect of the estimation error. In this paper, we used the standard deviation of average run length (ARL) as well as the average of ARL to quantify the between-practitioner variability in the CCC-r chart performance. The results indicate that the CCC-r chart requires larger Phase I data than previously recommended in the literature in order to have consistent chart in-control performance among practitioners.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.229-233
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• 2001

In this paper, we propose a remote controller for robot manipulator using local area network(LAN) and internet. To do this, we develope a server-client system as used in the network field. The client system is in any computer in remote place for the user to log-in the server and manage the remote factory. the server system is a computer which controls the manipulator and waits for a access from client. The server system consists of several control algorithms which is needed to drive the manipulator and networking system to transfer images that shows states of the work place, and to receive a Tmp data to run the manipulator. The client system consists of 3D(dimension) graphic user interface for teaching and off-line task like simulation, external hardware interface which makes it easier for the user to teach. Using this server-client system, the user who is on remote place can edit the work schedule of manipulator, then run the machine after it is transferred and monitor the results of the task.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.05a
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• pp.169-173
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• 2002

반도체 공정은 복잡하고 다양한 물리, 화학작용을 수반하며, 폭넓은 데이터 발생 및 관리에도 불구하고 공정진행시 내부 특성의 복잡함 때문에 효율적인 모델링이 어려웠다. 또한 원하는 출력을 얻기 위한 제어입력의 선정도 용이하지 않으므로 현재의 최적공정운영은 전문가의 경험에 의존하여 많은 시행 착오를 거쳐 수행되고 있다. 본 논문에서는 반도체 공정의 최적운영을 위해 다음 세 단계로 나누어 연구를 수행하였다. 첫째, 반도체 공정을 설비를 기반으로 컬러드 페트리 넷을 이용하여 모델링하고 둘째, Run-to-Run control에 기반한 최적공정운영 관리모델을 실험하고 셋째, 지식기반 데이터베이스를 기반으로 하는 지능적인 적응형 공정관리모델(Adaptive Process Control model)의 프레임 웍을 제안한다.

• Journal of Korean Academy of Nursing
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• v.21 no.3
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• pp.281-294
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• 1991

The purpose of this study was to determine the amount of soleus muscle atrophy in rats due to 28 days of decreased activity induced by hindlimb suspension, to observe the restoration of mass and relative muscle weight of the atrophied soleus muscle at day 28 of recovery to control value, and to compare the effect of run training on the mass and relative muscle weight of the atrophied soleus muscle at day 28 of recovery with that of sedentary rats. Adult female Wistar rats were maintained for 28 days with hindlimb suspension. Rats were then assigned randomly to a cage sedentary or running group. Soleus muscle mass and relative muscle weight following hindlimb suspension were compared with a control value. The soleus muscle mass and relative muscle weight of the running and cage sedentary groups following hindlimb suspension were compared with those of a control group. Soleus muscle mass and relative muscle weight of the run training group were compared with those of cage sedentary group. The results obtained were as follows : 1. Soleus muscle mass and relative muscle weight was reduced to 53.28% and 51.11% respectively by hindlimb suspension. 2. Soleus muscle mass and relative muscle weight of the training group t day 28 of recovery was restored to the control value. 3. Soleus muscle mass of the training group was greater than that of the cage sedentary group by 6.6% without statistical significance at day 28 of recovery. 4. Relative soleus muscle weight of the traning group was significantly greater than that of the cage sedentary group by 15.79% From these results, it may be concluded that run training during the posthypokinetic period facilitates the recovery of the atrophied soleus muscle mass of rats.

• Journal of Korean Society for Quality Management
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• v.43 no.4
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• pp.521-532
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• 2015

Purpose: The purpose of this study is to compare two multivariate cumulative sum (MCUSUM) charts designed for spatio-temporal surveillance in terms of not only temporal detection performance but also spatial detection performance. Method: Experiments under various configurations are designed and performed to test two CUSUM charts, namely SMCUSUM and RMCUSUM. In addition to average run length(ARL), two measures of spatial identification accuracy are reported and compared. Results: The RMCUSUM chart provides higher level of spatial identification accuracy while two charts show comparable performance in terms of ARL. Conclusion: The RMCUSUM chart has more flexibility, robustness, and spatial identification accuracy when compared to those of the SMCUSUM chart. We recommend to use the RMCUSUM chart if control limit calibration is not an urgent task.

• Communications for Statistical Applications and Methods
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• v.23 no.6
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• pp.497-515
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• 2016

Modern processes often monitor more than one quality characteristic that are referred to as multivariate statistical process control (MSPC) procedures. The MSPC is the most rapidly developing sector of statistical process control and increases interest in the simultaneous inspection of several related quality characteristics. Most multivariate detection procedures based on a multi-normality assumptions are independent, but there are many processes that assume non-normality and correlation. Many multivariate control charts have a lack of related joint distribution. Copulas are tool to construct multivariate modelling and formalizing the dependence structure between random variables and applied in several fields. From copula literature review, there are a few copula to apply in MSPC that have multivariate control charts, and represent a successful tool to identify an out-of-control process. This paper presents various types of copulas modelling for the multivariate control chart. The performance measures of the control chart are the average run length (ARL) and the average number of observations to signal (ANOS). Furthermore, a Monte Carlo simulation is shown when the observations were from an exponential distribution.