• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.1
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• pp.31-40
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• 2022

Six Sigma is a philosophy and systematic methodology for quality improvement. It encourages continuous quality improvement efforts to achieve the ideal goal of 6σ. Sigma(σ) is a statistic representing the standard deviation of the normal distribution, and 6σ level means a level where the tolerance of the specification is six times the standard deviation of the process distribution. In terms of the defective rate, the 6σ level achieves the 0.002 defectives per one million units. However, in the field, the 6σ level is used in the sense of achieving 3.4 defects per one million opportunities, which shows a large gap from the 6σ level in the statistical viewpoint. This is because field practitioners accept a 1.5σ shift of the mean of process when calculating the defective rate under sigma level. It said that the acceptance of 1.5σ shift of the mean is from experience, but there is no research or theoretical explanation to support it logically. Although it is a non-scientific explanation based on experience, considering that there has been no objection to the 1.5σ shift for a long time and it is rather accepted, it is judged that there is a reasonable basis for the 1.5σ shift. Therefore, this study tries to find a reasonable explanation through detective power of control chart via the run-rules to the 1.5σ shift empirically recognized by practitioners.

• Journal of Korean Society for Quality Management
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• v.32 no.1
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• pp.1-20
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• 2004

Six sigma has been the most influential management innovation program since 1996 in Korea. As a result of successful implementation of 6 sigma, there have been a number of dramatic quality improvement cases. However, no empirical study of 6 sigma implementation study has done especially in the service industry of Korea. This article reviews status of finance companies which implemented 6 sigma programs in Korea and then demonstrates the relationship between 6 sigma problem solving tools such as analysis of variance and graph techniques, etc and project success and operational performance. Customer survey tools, process analysis, and documentation tool are identified as influential tools on project success. Tools of measure steps, customer survey tools, and documentation tool are found as influential tools on operational performance.

• Journal of Korean Society for Quality Management
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• v.31 no.4
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• pp.81-94
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• 2003

Six sigma is a management innovation strategy which improves all managerial processes in an integrated manner, Six sigma can be applied to every aspect of managerial functions such as marketing, engineering, purchasing, accounting, and so on. Six sigma is trying to solve quality problems from the customer's viewpoint in the scientific manner, thus maximizing profits through the elimination of quality costs. This paper is presented to verify empirically the successful factors of implementing six sigma through the survey of black­belts of Korean firms. The blue­chip companies in Korea and across the world have already adopted Six Sigma, and it is becoming an integral part of the corporate culture of these companies. In conclusion, the most important factors to the success of six sigma are found to be the leadership of top management, and the compensation/ incentive system. The analysis also shows that the important factors are different in terms of both the process type and implementing stage.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.5
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• pp.66-77
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• 2008

Six sigma is a business strategy and a systematic methodology using statistically oriented approach to process and product quality improvement. Many cases have reported significant benefits from six sigma implementation. But, some organizations have been reported that six sigma methodology has not given the expected benefits. Further, small and medium sized companies have faced various barriers. The purpose of this paper is to examine the successful case study on the improvements of partnership between large and small/medium-sized companies via six sigma activities. Data were collected using in depth interviews of six sigma champion, master black belt, and black belt from one large company and five medium-sized companies in Gumi industry zone.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.509-517
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• 2010

The paper proposes the misuse types of statistical quality tools according to the kind of data and the number of population in DMAIC process of six sigma. The result presented in this paper can be extended to the QC story 15 steps of QC circle. The study also provides the improvement methods about control chart, measurement system analysis, statistical difference, and practical equivalence.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.10
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• pp.1132-1138
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• 2009

The spring constants of primary suspensions for a railway vehicle are optimized by a robust design process, in which the response surface models(RSMs) of their dynamic responses are constructed via the design of experiment(DOE). The robust design process requires an intensive computation to evaluate exactly a probabilistic feasibility for the robustness of dynamic responses with their probabilistic variances for the railway vehicle. In order to overcome the computational process, the process capability index $C_{pk}$ is introduced which enables not only to show the mean value and the scattering of the product quality to a certain extent, but also to normalize the objective functions irrespective of various different dimensions. This robust design, consequently, becomes to optimize the $C_{pk}$ subjected to constraints, i.e. 2, satisfying six sigma. The proposed method shows not only an improvement of some $C_{pk}$ violating the constraints obtained by the conventional optimization, but also a significant decrease of the variance of the $C_{pk}$.

• Journal of Korea Multimedia Society
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• v.21 no.6
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• pp.685-697
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• 2018

(Most companies that perform BPR have not achieved satisfactory results or have not performed successful BPRs. There are many reasons for this, but the most important one has caused problems that do not accurately reflect the requirements of various stakeholders. In this paper, we will apply the BPR consulting methodology to a new value innovation requirements engineering process based on the Blue Ocean strategy, which is a way to create a new market without competition by customerizing potential customers by satisfying new customer expectations and needs. This paper uses a requirements engineering process that can generate customer value by applying the ERRC(Erasure Reduce Raise Create) analysis method, which is the core of the Blue Ocean Strategy Framework[1,2]. We will also apply the Six Sigma DFSS (Design For Six Sigma) methodology to improve quality and process through quantitative and systematic analysis. The proposed approach was presented to the BPR consulting to present a practical case, and the results of the empirical analysis of the system user to validate the results of BPR consulting.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1257-1273
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• 2015

The development process of Embedded Software (SW) is gathering interest due to the increased importance of SW in mobile products. According to tough competition and the growing size of the Embedded SW, there is a demand for a new effective way to improve the SW development process, based on customer and market quality aspects, rather than focusing on defect removals in individual SW modules. We review 103 SW improvement projects from the area of mobile phones in order to check the effectiveness of Six Sigma which is the standard for the process improvement statistical tools and methods.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.431-436
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• 2006

6 Sigma uses DMAIC (Define, Measure, Analyze, Improve, Control) methodology as process of solving problem. Enterprise already propelling successfully 6 sigma such as Motorolla, GE and consulting companies leading 6 sigma also propose DMAIC methodology traditionally. But from making 6 sigma activated, enterprises and 6 sigma consulting companies propose 6 sigma methodology matching office indirection part and research and development part. As the forward example, DFSS(Design For Six Sigma) is R&D part application in GE. This study investigates 6 sigma methodology corresponding to Right Process of the kernel factor. Especially for optimum design of the R&D part, revise DFSS definition and general concept organization through Lean DFSS methodology research and analysis.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.353-358
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• 2003

Recently there has been huge efforts to improve performance in construction process by applying emerging techniques such as the Lean principle, Just-in-time concept and so on. However, little achievement as we expected has come out in reality due to the lack of strategy to set a definite goal of the execution and differences of personal viewpoints on construction productivity. Accordingly, it is the most important to promote the circumstances for the construction process improvement by quantifying the goals of respective unit activity groups. This research explores feasible solutions for the improvement of construction projects performance by combining the six-sigma principle for the generic administrative innovation based on the idea of construction process performance. For this purpose, mutual comparisons of various current approaches are performed in an attempt to establish the advantages in applying six-sigma idea and to provide its fundamental strategy. Furthermore, through a case study with the simulation of applying six-sigma to a unit activity group in construction process, this paper verifies that the overall performance improves as the degree of sigma level gets advanced.