• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.293-301
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• 2013

The purpose of this study is to introduce the limit of previously used six sigma quality process evaluation metrics, $Z_{st}$ and $P_{pk}$, and a solution to overcome this drawback by using a metric based on performance evaluation of Z-factor quality innovation. Case analysis on projects from national six sigma contest from 2011 to 2012 is performed and literature review on new drug development HTS (High Throughput Screening) is used to propose innovative performance evaluation metrics. This research shows that experimental study on six sigma evaluation metric, $Z_{st}$ and $P_{pk}$, have no significance difference between industrial type (Manufacturing, Semi-Public Institute, Public Institute) and CTQ type (Product Technology Type CTQ, Process Technology Type CTQ). Following discovery characterize this quality improvement as fixed target type project. As newly developed moving target type of quality innovation performance metric Z-Factor is used for evaluating experimental study, hypothetical analysis suggests that $Z_{st}$ and $P_{pk}$ share different relationship or even show reciprocal relationship. Constraints of the study are relatively small sample size of only 37 projects from past 2 years and conflict on having interview and communication with six sigma quality practitioner for qualitative experimental study. Both moving target type six sigma innovation project and fixed target type improvement project or quality circle enables efficient ways for a better understanding and quality practitioner use by applying quality innovation performance metric. Downside of fixed target type quality performance evaluation metric, $Z_{st}$ and $P_{pk}$, is presented through experimental study. In contrast, advantage of this study is that high throughput requiring product technology, process technology and quantum leap typed innovation effect is evaluated based on precision and accuracy and Z-Factor that enables relative comparison between enterprises is proposed and implemented.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1251-1262
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• 2011

K-company, being in charge of domestic railway construction and facilities management, got a success rate of 41% with the implement of a improvement scheme by prosecuting of 6 Sigma and the achievement of CTQ (Success criteria : more than 0.5 in achievement of CTQ). It is clear that the factors having an effect on achievement of CTQ are the level of project when pushing forward the project(Big Y and small y according to the scope of the work), the degree of interest of an officer in charge like sponsors, and the continuous feedback toward the implement of a improvement scheme. For improvement CTQ achievement, firstly redefine about a type of project. Secondly, derive small y by Big Y and derives a unit work by small y. Then grouping the unit works and achieve Big Y by performing of every unit work as an executive subject. Thirdly organize a committee of subject selection which is supervised by the general manager. Therefore exhibit staff's leadership, for example motivation, by strong incentives. Lastly, provide ongoing learning and enhance system monitoring about a result management of an betterment execution department.

• Korean Journal of Occupational Health Nursing
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• v.7 no.2
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• pp.155-163
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• 1998

In order to investigate the effects of rotating shift work on the subjective characteristics of sleep and mental depression questionnaire survey was carried out on 405 shift workers and 153 nonshift workers who were nurses employed. in three university hospital. The questionnaire forms used in this study were the self rating depression scale(SDS) and circadian type questionnaire(CTQ) factor R(rigidity/flexbility of sleeping habit) and factor V(inability/ability to overcome drowsiness). The results were as follows ; 1. Mean score of CTQ R in shift workers was significantly lower than that in nonshift workers, however, no significant difference in CTQ V was observed between two groups. 2. Mean score of SDS was significantly higher in shift workers(44.1) than in nonshift workers(39.8). 3. Mean self rating depression scale scores of pervasive affect, physiologic equivalents and psychological equivalents were significantly higher in shift workers than in nonshift workers. 4. In shift worker, mean SDS score was the highest in confusion and followed by diurnal variation, retardation, and indeciveness in the descending order. In nonshift worker, that score was the highest in decreased libido and followed by confusion, and indeciveness in the descending order. 5. Circadian type questionnaire scores was significantly and negatively correlated with significantly and negatively correlating with Self-rating depression scale scores(r=-0.473).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.21-28
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• 2015

As film products are increasingly used in a wide range of areas, from producing traditional flexible packaging to high-tech electronic products, a higher level of quality is demanded. Most film products are made in the form of rolled finished goods, therefore, various quality issues related to their shape characteristics must be addressed. The thickness of the film products is one of the most common and important critical-to-quality attributes (CTQs). Particularly, the degree of thickness uniformity is more important than other thickness parameters, because it will be potential causes of many secondary thickness-related quality problems, such as wrinkles or faulty windings. To control the degree of thickness uniformity, the fixed bending region is oneof the most important CTQs to manage. Fixed bending regions are special points in the transverse direction of a rolled product with consistent minute variations of the thickness gap. This paper describes the measurement and analysis of thickness uniformity data, which were performed in a real manufacturing field of biaxial oriented polypropylene (BOPP) film. In previous researches, quality function deployment (QFD) or fault tree analysis were used to find the most critical process attributes out to controlthe CTQ of thickness uniformity. Whereas, this paper uses traditional control charts to find the most critical process attributes out in this problem. In addition, the selection of one of the major critical process attributes (CTPs) that is expected to affect the CTQ of thickness uniformity is also described. The selected critical-to-process attributes are the controlled temperatures along the transverse direction. A dramatic improvement in thickness uniformity was observed when the selected CTPs were controlled.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.2
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• pp.36-41
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• 2006

This study was carried out to install the lifting force of a two hinge type stand mechanism by 6 Sigma process in advance. This unit is designed for the display device in order to enhance the ergonomics for effective height adjustment and maintenance at any preferred position. The unit will be very useful for the mechanism fabricated with coil springs and disc springs as a torque generator. The 6 Sigma process was applied to select two key factors among 7 elements to lift the head unit and to find out applicable tolerance securing the 3.4 ppm of defects as well as what deviation of lifting force we can expect between calculation and experiment at the design stage of development. The result of this study can be applied to various units for the optimization of the smooth lift.

• Korean Journal of Psychosomatic Medicine
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• v.29 no.1
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• pp.58-66
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• 2021

Objectives : The purpose of this study is to compare the psychosocial characteristics of patients diagnosed with functional gastrointestinal disorder (FGID) by classifying them into irritable bowel syndrome (IBS), functional dyspepsia (FD), functional constipation (FC), functional heartburn (FH) groups, and overlap group (two or more functional diseases) and to examine the factors associated with the quality of life (QoL) of patients with FGID. Methods : A total of 144 patients who were diagnosed with FGID were selected as the subjects. The demographical factors were investigated; Korean-Beck Depression Inventory-II (K-BDI-II), Korean-Beck Anxiety Inventory (K-BAI), Korean version of Childhood Trauma Questionnaire (K-CTQ), Multi-dimensional Scale of Perceived Social Support (MSPSS), Korean Version of Connor-Davidson Resilience Scale (K-CD-RISC), and World Health Organization Quality of Life Assessment Instrument Brief Form (WHOQOL-BREF) were used to evaluate the psychosocial factors. Results : TThe overlap group had a significantly higher K-BDI-II score (F=11.09, p<0.001) and K-BAI score (F=8.93, p<0.001) compared to other groups. In childhood trauma, the IBS patients had a difference in emotional neglect (F=2.54, p=0.04) than the FD patients. The QoL of FGID patients had a negative correlation with depression (r=-0.196, p<0.01), anxiety (r=-0.235, p<0.01), and childhood trauma (r=-0.222, p<0.01), and a positive correlation with social support (r=0.512, p<0.01) and resilience (r=0.581, p<0.01). Conclusions : Overlap group had a higher level of depression and anxiety, and the IBS patient group had a higher level of emotional neglect than the FD patient group in terms of childhood trauma.