• Communications for Statistical Applications and Methods
• /
• v.18 no.3
• /
• pp.377-389
• /
• 2011

A higher quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The third generation index $C_{pmk}$ is more powerful than two useful indices $C_p$ and $C_{pk}$ that have been widely used in six sigma industries to assess process performance. In actual manufacturing industries, process capability analysis often entails characterizing or assessing processes or products based on more than one engineering specification or quality characteristic. Since these characteristics are related, it is a risky undertaking to represent the variation of even a univariate characteristic by a single index. Therefore, the desirability of using vector-valued process capability index(PCI) arises quite naturally. In this paper, we consider more powerful vector-valued process capability index $C_{pmk}$ = ($C_{pmkx}$, $C_{pmky}$)$^t$ that consider the univariate process capability index $C_{pmk}$. First, we examine the process capability index $C_{pmk}$ and plug-in estimator $\hat{C}_{pmk}$. In addition, we derive its asymptotic distribution and variance-covariance matrix $V_{pmk}$ for the vector valued process capability index $C_{pmk}$. Under the assumption of bivariate normal distribution, we study asymptotic confidence regions of our vector-valued process capability index $C_{pmk}$ = ($C_{pmkx}$, $C_{pmky}$)$^t$.

• Communications for Statistical Applications and Methods
• /
• v.16 no.3
• /
• pp.449-461
• /
• 2009

Higher sigma quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The process capability indices and the sigma level $Z_{st}$ ave been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on statistical estimation under normal process which may result in unreliable assessments of process performance. In this paper, we consider statistical estimation for bivariate VPCI(Vector-valued Process Capability Index) $C_{pkl}=(C_{pklx},\;C_{pklx})$ under Marshall and Olkin (1967)'s bivariate exponential process. First, we derive some limiting distribution for statistical inference of bivariate VPCI $C_{pkl}$. And we propose two asymptotic normal confidence regions for bivariate VPCI $C_{pkl}$. The proposed method may be very useful under bivariate exponential process. A numerical result based on our proposed method shows to be more reliable.

• Proceedings of the Korea Contents Association Conference
• /
• 2004.05a
• /
• pp.406-414
• /
• 2004

It is being emphasized that management of core process is another crutial factor in the development of a product, besides of management of quality factors for the product itself. The study purposes to introduce process quality concept to digital contents market, and also aimes at meauring of process maturity, based on level 2 and 3 of Capability Maturity Model, for domestic companies especially devoted to digital contents area. The result shows that the maturity level of most of companies surveyed is very low and that mobile and game fields are slightly more matured than animation field. The paper also proposes some of future efforts to be made fur improving maturity level of digital contents companies.

• Journal of the Korea Safety Management & Science
• /
• v.1 no.1
• /
• pp.123-134
• /
• 1999

There are several models for process quality assurance by quality system (ISO 9000), process capability analysis, acceptance control chart and so on. When a high level process capability has been achieved, it takes a long time to monitor the process shift, so it is sometimes necessary to develop a quicker monitoring system. To achieve a quicker quality assurance model for high-reliability process, this paper presents a model for process quality assurance when the fraction nonconforming is very small. We design an acceptance control chart based on variable quality characteristic and time-censored accelerated testing. The distribution of the characteristics is assumed to be normal or lognormal with a location parameter of the distribution that is a linear function of a stress. The design parameters are sample size, control limits and sample proportions allocated to low stress. These paramaters are obtained under minimization of the relative variance of the MLE of location parameter subject to APL and RPL constraints.

• Proceedings of the Safety Management and Science Conference
• /
• 1999.11a
• /
• pp.247-257
• /
• 1999

There are several models for process quality assurance by quality system(ISO 9000), process capability analysis, acceptance control chart and so on. When a high level process capability has been achieved, it takes a long time to monitor the process shift, so it is sometimes necessary to develop a quicker monitoring system. To achieve a quicker quality assurance model for high-reliability process, this paper presents a model for process quality assurance when the fraction nonconforming is very small. We design an acceptance control chart based on variable quality characteristic and time-censored accelerated testing. The distribution of the characteristics is assumed to be normal of lognormal with a location parameter of the distribution that is a linear function of a stress. The design parameters are sample size, control limits and sample proportions allocated to low stress. These parameters are obtained under minimization of the relative variance of the MLE of location parameter subject to APL and RPL constraints.

• Journal of Information Technology Applications and Management
• /
• v.9 no.3
• /
• pp.113-127
• /
• 2002

The effort for software process improvement is lately surging its interest though it does not satisfy both developer and receiver In terms of low productivity, quality, delay and increasing cost. According to current research, software process improvement contributes to improvement of productivity, its Duality, reduction of development time and cost, and the prediction of the time limit for delivery, which means software process improvement affects competitive advantage among developers. The latest research is whether the investment for information technology substantially had effect on improvement of productivity. That is, software process improvement and maturity of software industries has influence upon economic efficiency and as a result, it plays an important role in whole industries. This research is that how does software process improvement using CMM (Capability Maturity Model) and SPICE (Software Process Improvement and Capability dEtermination) have a effect on factors of software engineering, and how does it have influence upon competitive advantage among SI firms. For this research, reusability, customizability, participation, and review & inspection are set to independent variable and process flexibility and process predictability are set to mediate Variable. Finally, competitive advantage among SI firms Is set to dependent variable. The targets for survey are laborers who work for SI firms. The result of this research is as follows: 1 ) Reusability, Customizability and participation is not rejected but review and Inspection is rejected in process flexibility which has significant level 0.05. 2) Reusability, Customizability and participation is not rejected but review and inspection Is rejected in process predictability which has significant level 0.05. 3) Process flexibility is not rejected and process predictability Is rejected in the competitive advantage of 51 industries which has significant level 0.05

• The KIPS Transactions:PartD
• /
• v.12D no.7 s.103
• /
• pp.937-946
• /
• 2005

In the current marketplace, there are maturity models, standards, methodologies and guidelines that can help an organization improve the way it does business. All SPI models including ISO/IEC I5504 and CMMI provide the capability level of software process. However, most available improvement models focus on a specific goals and Practices of the processes So my assessors need an objective process measure how to estimate achievement of goals and practices. We proposed quantitative process capability metric (PCM) which can determine the degree of capability And the effective measuring approach help SPI assessor as well as organization unit.

• Journal of the Korean earth science society
• /
• v.26 no.6
• /
• pp.461-468
• /
• 2005

The purpose of this study is to investigate the abilities of 6th grade students to assess the relationship between spatial capability, concept of celestial motion, and science process skills, which can help find a better teaching strategy for students in understanding the concept of celestial motion. The results are as follows. First, in terms of level of accomplishment of these three skills, male students show higher level of accomplishment than female students, but significant differences are found. Second, according to the analysis of the effect of spatial capability and concept of the movement of heavenly bodies, the former has a stronger influence on the students' cognition of celestial motion. Minor elements of spatial capability that influence the conception of celestial motion are device analogy, calculation of wood cut, and revolving light. Third, spatial capability is very influential on the level of accomplishment in science process skills. Among the minor elements of spatial capability that is influential to science process skills, calculation of wood cut is the highest, especially when various elements are interactively related to each other.

• Journal of the Korea Safety Management & Science
• /
• v.11 no.1
• /
• pp.131-136
• /
• 2009

The research develops the calculation steps of Z sigma level, process capability index(PCI) and process performance index(PPI) applicable to the discrete process in the service industry. The paper presents three following topics used related process indexes according to the precision and accuray in the continuous process. The contents include diverse process indexs for nonconformities by SPC attribute control charts and bias coefficient. The same technique of the nonconformites is also used in the nonconforming units. The practical examples are provided to help easier understanding for users.

• Proceedings of the Technology Innovation Conference
• /
• 1998.06a
• /
• pp.57-90
• /
• 1998

This study attempts to explore the evolution paths of Korean SMEs'strategies and their technological teaming processes. Several different evolution paths are identified based on a dynamic strategic group analysis of 115 SMEs'strategy in the Korean electronic component industry for the period of 1990-1995. Further, inadept case analyses on technological learning processes in 5 firms are undertaken. Major findings of this study can be summarized as follows : 1) There are three dominant evolution paths in SMEs'strategy. First path indicates the evolution from a subcontractor or petty imitator group(a strategic group with the narrow product/market domain and the low level of accumulated resource/capabilities) into an innovator group(a strategic group with the narrow domain but high level of technological capability) by accumulating technological capabilities. Second, some firms move from a subcontractor group into a generalizer group(a strategic group with broad product/market domain but relatively low level of technological capability) by simply adding product lines. Third path involves firms which evolve from a subcontractor group into a production focus group(a strategic group with high level of production capability) by investing in production capabilities. 2) An in-depth case analysis shows those who succeeded in technological learning are managed by CEOs, who have technological expertise and strategic vision, and have made an effort to establish management practices to support innovation, such employee educational program, performance-based reward system, etc. The successful firms also aggressively pursue diverse external linkages with outside technology sources to learn product and process technologies. Fiendly, this study discusses several implications of the findings for the theoretical development and strategic management of small firms in Korea.