• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.63
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• pp.65-77
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• 2001

A more technical perspective is needed in estimating the effect of the Manufacturing Process for improving the Productivity, there are many statistical evaluation methods, convenience sampling, frequencies, histogram, QC seven tools, control chart etc. It is more important for the companies to use six sigma to reduce defective and improve the process control than the technical definition as a disciplined quantitative approach for improvement of process control and a new way of quality innovation. Process network analysis is a technique which has the potentiality for a wide use to improve the manufacturing process which other techniques can't be used to analyze effectively. It has some problems to analyze the process with feedback loops. The branch probabilities during quality inspections depend upon the number of times the product has been rejected. This paper presents how to improve the manufacturing process by statistical process control using branch probabilities, Moment Generating Function(MGF) and Sensitivity Equation.

• Journal of Korean Society for Quality Management
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• v.35 no.2
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• pp.1-26
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• 2007

The purpose of this research is to suggest the promotive directions of Quality Circle activity. Since 1975, variety of organizations in Korea have widely the implemented Quality Circle activities for their management systems. Today, Companies are facing the harsh realities of a competitive environment. This is no time for revolutionary change. Instead, Companies are instituting revolutionary change meant to have impact within a very short time frame. The Worker's Quality Circle activity is, essentially, a trouble shooting oriented voluntary small group within their working place to improve the surroundings creatively. The industries have enthusiastically used Quality Circle activities and were influenced from them. The Quality Circle activities can be regarded as a kind of Knowledge Management where new knowledge is created and knowledge is shared in the economy. However, the academics were less interested in this subject, as a result, there were no systematic guidances for Quality Circle activities. Also, the government was less interested in these activities, as a result, there were no systematic policy making for Quality Circle activities. Thus, in this research, the promotive directions for Quality Circle activities were suggested which were based on the results of survey Questionnaires presented to promoters of the domestic companies. As a results of this research, to maximize the effect of TQM(Total Quality Management) in the nationwide, Quality Circle activity as a bottom-up management should be more expanded and revitalized.

• Journal of Korean Society for Quality Management
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• v.45 no.3
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• pp.561-582
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• 2017

Purpose: The purpose of this study is to share the right conception of win-win partnership innovative activity. This study suggests the desirable methodology to Win-win Partnership. Also, through the in-depth analyzing of the existing problems, we intend to exclude such a formal and erroneous direction of the research. Methods: This study systematically analyzes the best cases of the win-win partnership focusing on the proceedings of the companies participating in the field of win-win Partnership at the national quality-circle contest. Results: This study reveals the underlying problems of win-win partnership innovative activity and draws the conclusion in the way of improvement about the win-win partnership innovative activity. This study also suggests the efficient method of the function and improvement of a system for activating win-win partnership innovative activity. Conclusion: Promoting the effective way of boosting win-win partnership innovative activity, we seek to improve the quality of the product among the companies, and let the a rising curve of the mutual growth continue among the companies by strengthening the competitiveness.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.337-344
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• 2000

Purpose :To design and test test CT simulator phantom for geometrical test. Materials and Methods : The PMMA phantom was designed as a cylinder which is 20 cm in diameter and 24 cm in length, along with a 25$\times25\times31cm^{3}$ rectangular parallelepiped. Radio-opaque wires of which diameter is 0.8 mm are attached on the other surface of the phantom as a spiral. The rectangular phantom was made of four 24$\times24\times0.5 cm^{3}$ square plates and each plate had a 24$\times24 cm^{2}$, 12$\times12cm^{2}$, 6$\times6 cm$^{2}$ square line. The squares were placed to face the cylinder at angles 0 $^{\circ}$ , 15 $^{\circ}$ , 30 $^{\circ}$ ,respectively. The rectangular phantom made it possible to measure the field size, couch angle, the collimator angle, the isocenter shift and the SSD, the measurements of the gantry angle from the cylindrical part. A virtual simulation software, AcOSim, offered various conditions to perform virtual simulations and these results were used to perform the geometrical Quality assurance of CT simulator. Results : A 0.3$\~$0.5 mm difference was found on the 24 cm field size which was created with the DRR measurements obtained by scanning of the rectangular phantom. The isocenter shift, the collimator rotation, the couch rotation, and the gantry rotation test showed 0.5$\~$1 mm, 0.5$\~$l$^{\circ}$ 0.5$\~$ 1$^{\circ}$ , and 0.5-1 $^{\circ}$ differences, respectively. We could not find any significant differences between the results from the two scanning methods. Conclusion :The geometrical test phantom developed in the study showed less than 1 mm (or 1 $^{\circ}$ ) differences. The phantom could be used as a routine geometrical QC/QA tools, since the differences are within clinically acceptable ranges.

• The Journal of Korean Society for Radiation Therapy
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• v.11 no.1
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• pp.16-21
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• 1999

Purpose : The aim of this study is to conform the possibility of the liquid type EPID as a QC tools to clinical indication and of replacement of the film dosimetry. Aditional aim is to describe a procedure for the use of a EPID as a physics calibration tool in the measurements of radiation beam parameters which are typically carried out with film. Method & Materials : In this study we used the Clinac 2100c/d with EPID. This system contains 65536 liquid-filled ion chambers arranged in a $256{\times}256$ matrix and the imaging area is $32.5{\times}32.5cm$ with liquid layer thickness of 1mm. The EPID was tested for different field sizes under typical clinical conditions and pixel values were calibrated against dose by producing images using various thickness of lead attenuators(lead step wedge) using 6 & 10MV x-ray. We placed various thickness of lead on the table of linear accelerator and set the portal vision an SDD of 100cm. To acquire portal image we change the field size and energy, and we recorded the average pixel value in a $3{\times}3$ pixel region of interest(ROI) at field center was recorded. The pixel values were also measured for different field sizes in order to evaluate the dependence of pixel value on x-ray energy spectrum and various scatter components. Result : The EPID, as a whole, was useful as a QA tool and dosimetry device. In mechanical check, cross-hair centering was well matched and the error was less than ?2mm and light/radiation field coincidence was less than 1mm also. In portal dosimetry the wider the field size the the higher the pixel value and as the lead thickness increase, the pixel value was exponentially decreased. Conclusions : The EPID was very suitable for QA tools and it can be used to measure exit dose during patients treatment with reasonable accuracy. But when indicate the EPID to clincal study deep consideration required

• Korean Journal of Digital Imaging in Medicine
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• v.10 no.1
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• pp.21-28
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• 2008

Diagnostic display monitor QA according to AAPM TG18 is usually performed by PACS administrator, product manager and reading doctor, and for acceptance testing and periodic quality control evaluation, a combination of visual and quantitative tests can be used, as outlined in sections 5 and 6 of 'assessment of display performance for medical imaging systems'. Although many display tests can be performed visually, a more objective and quantitative evaluation of display performance requires special test tools. The required instruments vary in their complexity and cost, depending on the context of the evaluation(research, acceptance testing, or quality control) and how thorough the evaluation needs to be. Objective and reliable assessment of many display characteristics can be performed with relatively inexpensive equipment, So, we made 'AAPM TG18 guiding instrument' to ues variable purpose of the evaluation of 'geometrical distortions(quantitative"', 'veiling glare(visual)' and 'sensor calibration'. The spatial measurements for the quantitative evaluation of geometric distortions, and the measurement of the veling-glare ring response function which provides information regarding the spatial extent of the luminance spread, can be performed using the TG18 guiding instrument can be used to sensor calibration to standardize the basic rate of 0% luminance when periodic calibration.

• Industry Promotion Research
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• v.3 no.1
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• pp.43-48
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• 2018

This study is focusing on activating and developing the right model of win-win partnership innovative activity for the purpose of win-win relationship among companies. These are the following studies that are conducted for that objective. First, This study systematically analyzes the best cases of the win-win partnership focusing on the proceedings of the companies participating in the field of win-win Partnership at the national quality-circle contest for the last three years(2014~2016). This study reveals the underlying problems of win-win partnership innovative activity and draws the conclusion in the way of improvement about the win-win partnership innovative activity. Second, This study suggests the efficient method of the function and improvement of a system for activating win-win partnership innovative activity by analyzing screening criterion and selecting excellent cases in the field of win-win Partnership at the national quality-circle contest in 2017. Third, This study suggests the method of strengthening the system of sharing result for invigorating and motivating the win-win partnership innovative activity. It is expected that this methodology for reinforcing the system of Win-win Partnership among companies will help to create the environment where a sound and new corporate culture can be settled. And It is also expected that this study can contribute to attaining the goal of growing together through enhancing the competitiveness, productivity and quality among Win-win Cooperation companies.