• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.20 no.44
• /
• pp.153-161
• /
• 1997

This paper has proposed the modelling by simulation in order to evaluate the performance of process through discrete event simulation using SIMAN language in flexible manufacturing systems. The production system is assumed to be a job shop type of system under the batch production of discrete products. In this paper, the input data is the workstation(process) time, the number of workstation(process), a probability distribution, the number of simulation runs. Also, transient period is considered. In the case study, this paper deals with three products in real flexible manufacturing systems. Finally, a number of simulation runs were executed under different experimental conditions to obtain preliminary statistics on the following performance measures: operating rate of facility and average system operating rate, transient period, central processing unit, average system throughput, and average waiting time in queues.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.24 no.66
• /
• pp.19-26
• /
• 2001

I propose the control chart pattern to provide a more comprehensive scheme for detecting process X and R shifts using individual observations in start-up process. It is important to automate the identification of special disturbances to facilitate real-time manufacturing. This papers formulates X-R charts for interpretation by artificial neural networks. In this papers, which uses the backpropagation algorithm, two samples are fed into the trained neural network to provide outputs ranging from 0 to 1. Simulation results sow that the performance of the proposed control chart using the neural network(NNCC) is quite promising. Using these NN charts, guidelines are given for detecting and classifying process X and R shifts.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.4
• /
• pp.49-53
• /
• 2013

If industrial safety statistics are analyzed, among the total of 2,114 dead people from industrial disasters in 2011, construction workers took 29.4% with 621. The construction industry makes a lot of efforts to reduce the death toll. However, since the measures are not from the analysis of root causes but from superficial countermeasure plans near general matters, it is in a situation that the actual effectiveness is marginal. Therefore, in this paper, improvement measures were intended to be prepared in order to reduce accidents, by inspecting safety control systems of target companies with high accident rates among major construction firms and extracting overall problems of them.

• Journal of Industrial Technology
• /
• v.21 no.B
• /
• pp.117-123
• /
• 2001

In a modern control field, a control engineer who has theoretical backgrounds with some practical knowledge is demanded. That is to say, an engineer who can understand and operate the various parts such as modeling, simulation, system analysis, signal processing, statistics, and hardware is required. In order to prove the theoretical backgrounds and operate various hardwares, a lot of experimental devices for students are designed in universities. Since the conventional experimental devices are manufactured abroad and the prices of the devices are too high, it is difficult to have. If a low cost experimental device can be developed, it will be very useful for a control engineering education. In Ibis paper, an experimental rig which has two control inputs and three sensor outputs to control the end point of a flexible beam is designed and manufactured. This rig can be used for a control field education.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.20 no.1
• /
• pp.37-50
• /
• 2016

A large eddy simulation (LES) of a turbulent channel flow is performed by using the third order low-storage Runge-Kutta method in time and second order finite difference formulation in space with staggered grid at a Reynolds number, $Re_{\tau}=590$ based on the channel half width, ${\delta}$ and wall shear velocity, $u_{\tau}$. To reduce the calculation cost of LES, algebraic wall model (AWM) is applied to approximate the near-wall region. The computation is performed in a domain of $2{\pi}{\delta}{\times}2{\delta}{\times}{\pi}{\delta}$ with $32{\times}20{\times}32$ grid points. Standard Smagorinsky model is used for subgrid-scale (SGS) modeling. Essential turbulence statistics of the flow field are computed and compared with Direct Numerical Simulation (DNS) data and LES data using no wall model. Agreements as well as discrepancies are discussed. The flow structures in the computed flow field have also been discussed and compared with LES data using no wall model.

• Journal of Korea Society of Industrial Information Systems
• /
• v.7 no.5
• /
• pp.195-203
• /
• 2002

The purpose of this study is to investigate how QS 9000 Certification might influence company and analyze the effectiveness. Recently most companies are enforced to adapt quality assurance system, such as ISO series, QS 9000 etc, from domestic or foreign certification institutes. Therefore it is very important for all the company to acquire QS 9000 certification. Three Big UㆍS automakers had developed the QS 9000 quality System for their suppliers to implement the ISO 9000 based quality system. To analysis the effects of QS 9000 Quality System for quality improvement of the suppliers data had been gathered on the certification activities through questionnaire and been analyzed by descriptive statistics.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.324-325
• /
• 2011

This paper addresses the assessment of voltage sag costs based on the stochastic prediction of voltage sags. When voltage sags below a certain voltage threshold occur at sensitive industrial process, the industrial customer will experience financial damage. In order to mitigate voltage sag costs and devise efficient solutions to mitigate damage, a study on the financial loss assessment of voltage sags is basically needed. In order to assess the voltage sag costs, the expected sag frequency at a sensitive load point should be calculated by using the concept of the area of vulnerability and historical fault statistics. Then, financial loss due to voltage sags can be obtained by multiplying the expected sag frequency by the cost per sag event.

• Journal of Korean Society for Quality Management
• /
• v.24 no.1
• /
• pp.61-72
• /
• 1996

It is very important to determine the likelihood ratios and the prior odds for designing a Bayesian processor in Built-In-Test system. Using traditional statistics, it is not difficult to determine the initial prior odds from the field data. For a newly designed system, development testing data or laboratory testing data could be used to replace field data. The likelihood ratios which playa key role in the Bayesian processor must be carefully determined, based on laboratory testing and statistical techniques. In this paper, expressing and determining the likelihood ratios by Geometric areas, Test, and Analytical method will be presented.

• Journal of Korean Society for Quality Management
• /
• v.24 no.4
• /
• pp.29-43
• /
• 1996

This paper identifies these data by the data diagnosis in lognormal distribution and presents the method to obtain exact parameter estimates and confidence intervals of regression line. The life-stress relationship uses Arrhenius model and life data generate Class-H insulation complete data by simulation. Also, the method to estimate parameters uses least squares estimation and externally Studentized residuals can be used as test statistics for identifing outliers. And influential cases are identified by Cook's distance. This research is intended to obtain the useful information for the life of products and test method, to save time and costs, and to help optimum accelerated life test plans.

• Journal of the Korean Society of Safety
• /
• v.19 no.4 s.68
• /
• pp.94-100
• /
• 2004

This study delivers the actual condition of investment for industrial accident prevention based on survey of 500 construction sites from 'reports for industry safety and health' published by Korea Occupational Safety & Health Agency (KOSHA). The various research techniques were used such as technical statistic analysis for construction industry, cost comparison of industrial accident prevention and accident loss. A formula was deduced to calculate accident loss and accident frequency by accident prevention cost through regression analysis.