• 한국병원경영학회지
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• 제9권3호
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• pp.128-142
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• 2004

To evaluate the effects of critical pathway on the length of hospital stay, the cost and quality of care provided to gastrectomy patients in a tertiary care academic medical center. The basic research design is a retrospective case-control comparative study. 470 patients of gastrectomy were included in the study; 180 before pathway development (control), 163 right after pathway implementation (path group I) and 127 one year after pathway implementation (path groupII). 476 patients of modified radical mastectomy were also analyzed to examine whether the reduction of the length of hospital stay is from the hospital-wide trend or due to the critical pathway. Death after operation, ICU stay, unplanned re-operation, readmission after discharge, the length of hospital stay and cost were analyzed. 2-test, one-way ANOVA, Bonferroni and Turkey's test were used for statistical analysis. (1) There were no significant differences in patient clinical conditions and no sign of deterioration of quality from critical pathway. (2) The length of hospital stay was 13.0 days in control group, 12.2 days in path group I and 10.0 days (p<0.01) in path groupII. (3) The total costs during the hospital stay were reduced. However the cost per day was significantly increased from reduction of hospital stay (358,488won in control, 366,017won in path group I and 413,220won (p<0.01) in path groupII). Critical pathway reduced the length of hospital stay, total hospital costs and resource utilization without harming quality of patient care.

• International Journal of Quality Innovation
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• 제9권3호
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• pp.71-91
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• 2008

The definition of cycle time is the time from the wafer start to the wafer output. It usually takes one or two months to get the product since customer decides to produce it. The cycle time is a critical factor for customer satisfaction because it represents the response time to the market. Long cycle time reflects the ineffective investment for the capital. The cycle time is very important for foundry because long cycle time will cause customer unsatisfied and the order loss. Consequently, all of the foundries put lots of human source in the cycle time improvement. Usually, we make decisions based on the experience in the cycle time management. We have no mechanism or theory for cycle time management. We do work-in-process (WIP) management based on turn rate and standard WIP (STD WIP) set by experiences. But the experience didn't mean the optimal solution, when the situation changed, the cycle time or the standard WIP will also be changed. The experience will not always be applicable. If we only have the experience and no mechanism, management will not be work out. After interview several foundry fab managers, all of the fab can't reflect the situation. That is, all of them will have an impact period after product mix or utilization varied. In this study, we want to develop a formula for standard WIP and use statistical process control (SPC) concept to set WIP upper/lower limit level. When WIP exceed the limit level, it will trigger action plans to compensate WIP Profile. If WIP Profile balances, we don't need too much WIP. So WIP level could be reduced and cycle time also could be reduced.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.225-231
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• 2002

POSCO $\#2$ Stainless steel making plant produces more than 600 thousand ton per year with a variety of products consisting of austenite and ferrite stainless steel to meet custrmers' needs since 1996. The plant has four different major processes, that are, EAF-AOD-VOD-CC to finally produce semi-product called as slab. In this study, we importantly took AOD process into consideration due to its roles such as to check and verify the final qualities through sampling inspection. But the lead-time from sampling to its verification takes five to ten minutes causing produrtivity loss as muck as the lead-time as a result. Of all indices for quality and process control the plant has, carbon ingredient in liquid type of steel is the most important since it affects in a great way to the characteristics of steel, if any problem. customers not satisfied with quality could issue a claim; therefore there is no way hut to guarantee it before delivery. in this study, to reasonably reduce lead-time ran save a cycle time and finally improve our productivity from a state-or-art alternative just such as applying statistical model based on multi-regression analysis into the A.O.D line by analyzing the statistical and technical relationship between carbon and the relevant some vital independent variables. In consequence, the model with R-square $87\%$ allowed the plant to predict, abbreviating the process in relations to sampling to verification. approximately the value of [C] so that operators could run the process line with reliability on data automatically calculated instead of actual inspection. In the future, we are going to do the best to share this type of methodology with other processes, if possible, to apply into them.

• 응용통계연구
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• 제26권6호
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• pp.903-913
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• 2013

최근 소셜 네크워크 서비스의 발달로 인해 개인의 감정이나 의견을 표현하는 소셜 데이터들이 하루에도 수백만 건씩 생산되고 있다. 또한 소셜 데이터는 개인의 의견에 또 다른 생각을 더하는 등 정보의 생산과 소비가 누구나 가능해짐으로써 사회현상을 잘 반영해주는 도구로 성장하고 있다. 본 연구에서는 블로그에 올라온 부정적인 감성어들을 분석하여 블로거의 감성변화를 탐지하기 위해 다변량 관리도를 이용하고자 한다. 이를 위해 2008년 1월 1일부터 2009년 12월 31일 사이에 생성되었던 모든 블로그를 사용하였다. 품질 특성치가 다변량으로 주어지는 경우 호텔링의 $T^2$ 관리도가 널리 사용된다. 그러나 이 관리도는 품질 특성치들의 분포가 다변량 정규분포라는 가정을 하고 있어, 비정규 다변량 자료에 대한 관리도의 성능은 좋지 않다. 이에 본 논문에서는 Sun과 Tsung (2003)이 제안한 써포트 벡터머신에서 단일 집합 분류 기법 중 하나인 SVDD(support vector data description) 알고리즘과 이를 확장한 K-관리도를 소개하고, 실제 데이터 분석에 적용해 보았다.

• 품질경영학회지
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• 제35권4호
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• pp.89-100
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• 2007

The Purpose of this study was to investigate the relationship between transformational leadership and organizational citizenship behavior(OCB), and the relationship between transactional leadership and organizational citizenship behavior as well as to test the moderating effects of the Locus of Control(LOC) as the personal characteristics variable. The sample for this study consisted of 356 administrative employees from 18 universities located in Chung-Nam Province. Cronbach's alpha factor analysis, multiple regression analysis and hierarchical multiple regression were used for the statistical methods. The practical implications of the findings and suggestions for future research were discussed.

• 대한산업공학회지
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• 제32권4호
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• pp.298-313
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• 2006

Six sigma is focused on quality improvement through variation reduction, while lean is on process flow improvement and lead time reduction by waste elimination. However, lean cannot bring a process under statistical control and six sigma alone cannot dramatically improve process speed. Lean six sigma was developed to achieve faster rate of improvement in customer satisfaction, cost, quality, process speed, and invested capital. In this paper we present the importance of using value stream mapping and suggest a guideline on how to integrate lean and six sigma by is proposed.

• 품질경영학회지
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• 제40권1호
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• pp.15-24
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• 2012

For the construction of fractional factorial designs, the various arrays can be widely used. In this paper we review the statistical properties of fractional designs constructed by two arrays such as orthogonal array and partially balanced array, and develop a quick and easy method for analyzing unreplicated saturated designs. The proposed method can be characterized that we control the error rate by experiment-wise way and exploit the multivariate Student $t$-distribution. Especially the proposed method can be used efficiently together with some exploratory analysis methods, such as half normal probability plot method.

• 한국경영과학회지
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• 제23권3호
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• pp.109-122
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• 1998

A Process Quality Information System (PQIS) for the CIM environment is presented. The system includes three subsystems which are qualify control, statistical analysis, and information management. As part of CIM, the PQIS was designed by using the ICAM Definition(IDEF) methodology. The Oracle-CDE was utilized as a graphic development tool which made the system more user friendly. PQIS operates on IBM or compatible PCs under MS-Windows and Oracle DBMS. The methodology developed in this research provides a foundation for the application of CIM subsystems.

• 한국해양공학회지
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• 제13권2호통권32호
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• pp.66-73
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• 1999

This paper presents the experimental examinations and statistical quantitative analysis of the correlation between the cumulative counts of acoustic emission(AE) during plastic deformation periods of the welding and the tensile strength and other properties of the tube-to-tube welded joints of O.D. 30mm (I.D 18mm) nozzle steel. This is a new approach which attempts finally to develop real-time quality monitoring system for friction welding. And this study results in practical possiblility of real-time quality control more than 100% joint efficiency showing good weld no micro structural defects.

• 종양간호연구
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• 제3권1호
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• pp.45-55
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• 2003

Self-help group program is an elective procedure intended to improve the quality of life of women undergoing mastectomy. The purpose of this study is explore effects of the self-help group program for QOL after mastectomy. 40 Women who had undergone mastectomies between stagel to 3 were recruited. Subjects of experimental group attended the self-help group for 4 weeks. Data were collected by self-reporting questionnaire. QOL was assessed using the Quality of Life Scale(QLS) translated by Kwon(1990). As a results, no significant differences were found between experimental and control group in changes of QOL. But, experimental group increased QOL score. In conclusions, when the self-help group program is provided to the patients with breast cancer, it can be helpful for promoting QOL and emotional support, even no statistical difference. For the further study, repeated researched with appropriate duration of intervention is suggested. Significant anxiety about their disease and fear of recurrence will be persisted despite intervention.