• International conference on construction engineering and project management
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• 2007.03a
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• pp.433-439
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• 2007

A ubiquitous environment in construction requires integrating hardware and software systems. Currently the Construction System Integration Lab (CSIL) at Pusan National University is currently studying the application of ubiquitous technology for better communication in the construction process. In this paper, a pilot of Ubiquitous Concrete Pour System (u-CPS) has been presented to demonstrate the effectiveness of data exchange in the concrete pour process. The u-CPS environment takes advantage of the RFID technology for collecting construction data. The pilot can automatically generate the data for concrete pour work such as departure time, arrival time, concrete pour time. Construction managers can keep track of the progress of concrete pour work using the information. A case study was done for a building construction using the pilot system, the result of which demonstrated that the RFID-base system can help improve the effectiveness of data communication during the concrete pour process.

• Journal of Welding and Joining
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• v.8 no.1
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• pp.31-42
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• 1990

Arc must be stable during welding first of all other factors for obtaining sound weldment, especially in the automation of welding process. Arc stability is somewhat sophisticated phenomenon which is not clearly defined yet. In consumable electrode welding, the voltage and current variation due to metal transfer enables to assess arc stability. Recently, statistical analyses of the voltage and current waveform factors are performed to assess the degress of arc stability which is assessed and controlled by operator's own experience by now. But, considering the increasing need and the trend of automation of welding process, it is necessary to monitor arc stability in real-time. In this sutdy, the modified stability index composed of two voltage and current wvaeform factors (arc time and short circuit time) reduced from four factors (arc time, short circuit time, average arc current and average short circuit current) in Mita's index by the welding electrical circuit modeling is proposed and verified by experiments to be well estimating arc stability in the static sense. Also, the recursive calculation form estimating present arc stability in the dynamic sense is developed for real-time estimation. The results of applying the recursive index during welding show good estimation of arc stability in real-time. Therefore, the results of this study offers the mean for real-time control arc stability.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.1
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• pp.53-63
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• 2018

In this paper, we analyze the waiting time of a queueing system with D-BMAP (discrete-time batch Markovian arrival process) and D-policy. Customer group or packets arrives at the system according to discrete-time Markovian arrival process, and an idle single server becomes busy when the total service time of waiting customer group exceeds the predetermined workload threshold D. Once the server starts busy period, the server provides service until there is no customer in the system. The steady-state waiting time distribution is derived in the form of a generating function. Mean waiting time is derived as a performance measure. Simulation is also performed for the purpose of verification and validation. Two simple numerical examples are shown.

• 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.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.171-178
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• 2013

Workers are avoiding production/manufacturing sites due to the poor working environment and concern over safety. Small and medium-sized businesses introduce new equipment to secure safety in the production site or ensure effective process management by introducing the real-time monitoring technique for existing equipment. The importance of real-time monitoring of equipment and process in the production site can also be found in the ANSI/ISA-195 model. Note, however, that most production sites still use paper-based work slip as a process management technique. Data reliability may deteriorate because information on the present condition of the production site cannot be collected/analyzed properly due to manual data writing by the worker. This paper introduces the monitoring and process management technique based on a direct facility interface to secure safety in the field by improving the poor working environment and enhance there liability and real-time characteristics of the production data. Since the data is collected from equipment in real-time directly through the SIB-based interface and PLC-based interface, problems associated with workers' manual data input are expected to be solved; safety can also be improved by enhancing workers' attention to work by minimizing workers' injuries and disruption.

• Research in Community and Public Health Nursing
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• v.13 no.4
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• pp.732-742
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• 2002

There are few research on the social drinking experience reported by women. Thus, it is necessary to understand the increasing tendency of womens drinking experience in the sociocultural context. This study was aimed to explore and delineate the drinking experience of full-time house wives base don Strauss and Corbin's grounded theory (1998). The subjects of this study were 10 full-time middle-aged house wives who were living in Seoul region. The data were collected through several in-depth interviews and observations until the theoretical saturation was achieved. The data were analyzed using Strauss and Corbin's grounded theory method. The results of this study generated a paradigm that the drinking experience of the full-time middle-aged house wives has a core category of 'free-oneself-from' and is also connected with mingling, anguish, accessibility, reaction of other people, change, personal resources, self-expression and building relationships by drinking. All processes from the occurrence of the central phenomenon to extinction are as follows; 1) Starting the process of the drinking experience for mingling and resolving anguish, and by having an easy accessibility; 2) Perceiving the process of reaction by other people, physical change of herself. and psycho-behavioral change; 3) Experiencing the process of free-oneself from thorough drinking; 4) Acknowledging the process of the resources for free-oneself-from; 5) Selecting the process of self-expression according to the resources; 6) Building the process of the relationship with drinking as a way of self-expression. Based on this paradigm, 4 hypothesis and 4 types are generated. Thus, this study suggests that it is useful to develop nursing interventions to improve the self-esteem of the full-time middle-aged house wives and to provide them various methods of problem solving strategies. This study also proposes that there should be a strategic program for the women so that they could make a route for positive self-expression by achieving a proper relationship with drinking.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.115-122
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• 2020

In this paper, we propose an MES system based on real-time process capability management and how to manage the manufacturing process using the system. The current MES system presents a KPI report that makes it easy to recognize the manufacturing site, but has not been able to derive an improvement method to improve the actual manufacturing site KPI. In other words, it is difficult to extract the cause of the increase in defective rate, decrease in yield, and increase in production lead-time, and to draw an improvement plan and apply it to the manufacturing site. The purpose of the MES system based on real-time process capability management proposed in this paper is to establish an manufacturing operation management system that overcomes the limitations of the existing MES by managing the distribution of major factors of the equipment that determines the process capability. In addition, by presenting a speed improvement method for real-time large-capacity data processing, it is intended to be applied so that the system can operate well.

• Journal of the Korea Society for Simulation
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• v.20 no.4
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• pp.67-79
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• 2011

The statistical process control (SPC) assumes that observations follow the particular statistical distribution and they are independent to each other. However, the time-series data do not always follow the particular distribution, and most of cases are autocorrelated, therefore, it has limit to adopt the general SPC in tim series process. In this study, we propose a MPBC (Model Parameter Based Control-chart) method for fault detection in time-series processes. The MPBC builds up the process as a time-series model, and it can determine the faults by detecting changes parameters in the model. The process we analyze in the study assumes that the data follow the ARMA (p,q) model. The MPBC estimates model parameters using RLS (Recursive Least Square), and $K^2$-control chart is used for detecting out-of control process. The results of simulations support the idea that our proposed method performs better in time-series process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.5
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• pp.45-51
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• 2018

Roll forming refers to the production of long plate-molded products, such as panels, pipes, tubes, channels, and frames, by continuously causing the bending deformation to thin plates using rotating rolls. As the roll forming method has advantages in terms of mass production because of its excellent productivity, the size of the roll forming industry has been continuously increasing and the roll forming method is increasingly being used in diverse industrial fields as a very important processing method. Furthermore, as the roll forming method mainly depends on the continuous bending deformation of the plate materials, the time and the cost of the heterogeneous materials developed in the process are relatively large when considered from the viewpoint of plastic working because many processes are continuously implemented. The existing studies on roll forming manufacturing have reported the loss of large amounts of time and materials when the raw materials or product types were changed; further, they have stated that the use of this method can hardly guarantee the uniformity of the formed shapes and the consistency in terms of size and cannot detect all the defects occurring during the mass production and related to the dimensions. Therefore, in this research, a real-time process data-based smart roll forming method that can be applied to multiple products was studied. As a result, a roll forming system was implemented that remembers and automatically sets the changes in the finely adjusted values of the supplied quantities of individual heterogeneous materials so that the equipment setting changing time for heterogeneous material replacements or changes in the products being produced can be shortened. It also secures the uniformity of the products so that more competitive and precise slide-rail products can be mass-produced with improvements in the quality, price, and productivity of the products.

• Communications for Statistical Applications and Methods
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• v.5 no.2
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• pp.373-381
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• 1998

In this paper a new control chart which accounts for correlation between process subgroups will be proposed. We consider the case where the process fluctuations are autocorrelated by a stationary AR(1) time series and where n($\geq1$) items are sampled from the process at each sampling time. A simulation study is presented and shows that for correlated subgroups, the proposed control chart makes a significant improvement over the traditionally employed X-bar chart which ignores subgroup correlations. Finally, we illustrate the proposed chart by comparing the standardized residuals and X-bar chart on a data set of motor shaft diameters.