This paper presents a periodic replacement policy for a system subject to shocks when the system is operating for a finite random horizon. The system is subject to shocks during operation, and each shock causes downgrading of the system performance and makes it more expensive to run by the additional running cost. Shocks arrive according to a nonhomogeneous or a renewal process, and we develop periodic replacement policies under a finite random operating horizon. The optimum periodic replacement interval which minimizes the total operating cost during the horizon is found. Numerical examples are presented to demonstrate the results.
This paper presents another maintenance policy for a group of units under finite operating horizon. A group of identical units are subject to random failures. Group maintenances are performed to all units together at specified intervals, and the failed units during operation are remained idle until the next group maintenance set-up. Unlike the traditional assumption of infinite operating horizon, we adopt the assumption of the finite operating horizon which reflect the rapid industrial advance and short life cycle of modern times. The units are under operation until the end of the operating horizon. Further, the operation of units are extended to the first group maintenance time after the end of the horizon. The total cost under the proposed maintenance policy is derived. The optimal group maintenance interval and the expected number of group maintenances during the horizon are found. It is shown that the proposed policy is better than the classical group maintenance policy in terms of total cost over the operating horizon. Numerical examples are presented for illustrations.
In this study, we suggest a standardization of the logistics terminologies in Korean Standard to improve its consistency. To support this work, some principles for terminology selection and corrections are studied based on the guideline in international standard. The revised terminologies are summarized in Appendix for 20 logistics-related Korean Standards.
In this study, the mean time to failures of a system under shock models are derived. The system receives shocks according to a stochastic process. The expected system lifetime under homogeneous Poisson shock process, nonhomogeneous Poisson shock process, and a general renewal shock process are derived. Some numerical examples are presented.
Business organizations are trying in various ways to survive and grow up in the rapidly changing environment. A lot of organizations have introduced management innovation skills and attempted to change, but most of them have failed to realize their aims. The reason is that the members of the organization including the chief executive officers did not understand the paradigm of the change management of an organization, and gave weight to the partial efficiency instead of the change management of the organization. In this study, guidelines and principles are suggested to apply the quality management system to the change management of business organizations.
This paper analyzes the competitive power of domestic software industries focusing on the subjective rating of software development process. A survey is conducted to perform subjective evaluation of software development process of his/her company. Comparison between SPICE-experienced companies and non-experienced companies, between domestic companies and companies in developed countries are performed.
The certification of software products can provide a greater level of acceptance and feeling of security to customers of these products. This paper presents a certification method for the quality of package software. First of all, the evaluation criteria are derived from IS0/1EC 9126 and 12119 standards, and then the evaluation module are designed considering the measurement scale type. The results can be applied to construct the certification scheme of software product quality for the commercial purpose.
The certification of software products can provide a greater level of acceptance and feeling of security to customers of these products. This paper presents a certification method for the quality of package software. First of all, the evaluation criteria are derived from ISO/IEC 9126 and 12119 standards, and then the evaluation module are designed considering the measurement scale type. The results can be applied to construct the certification scheme of software product quality for the commercial purpose.
This paper presents the interrelationship chart between software quality characteristics and engineering attributes. The software quality characteristics and their subcharacteristics are excerpted front IS0/1EC 9126 standards, and the engineering attributes are from Deutsch and Willis[4]. Based on the previous studies and subjective judgement, trisected interrelationship(strong, medium, weak) between these two groups are derived. The results are summarized in a table, and can be used as a quick reference guide to the software quality engineering applications such as quality evaluations for software products, selection of key engineering attributes for high-quality software production, and so forth.
This paper presents the interrelationship between software quality character and engineering attributes. The software quality characteristics and subcharacteristics are excerpted from IS0/IEC 9126 standards, and the engineering attributes are from Deutsch and Willis〔4〕. Based on the previous studies a subjective judgement, trisected interrelationship(strong, medium, weak) bet these two groups are derived. The results are summarized in a table, and can be used as a quick reference guide to the software quality engineering application such as quality evaluations for software products, selection of key engineering attributes for high-quality software production, and so forth.
In this paper, the QFD(quality function deployment) technique is used to acquire the quality requirements of package software which is sold in a commercial software shop. To select the principal quality characteristics of package software, an user survey was conducted for a quality model developed based on the international standards and the previous research. The software user is divided into three groups:the general user, the expert, and the developer. The method of QFD is applied to choose the software quality attributes which have strong correlation with the selected quality characteristics.
Burn-in is a test procedure to find and eliminate the inherent initial failure of a product during or at the final stage of production process. Software testing is the validation and verification process which is used to cut off the faults from a software. The two have the common function and objective of "debugging". This article summarizes some significant models on the optimal hardware and software burn-in time, and provides the relevant paper lists. The need for the development of the unified burn-in policy of a hardware-software system is addressed.addressed.