ISSN:0748-8017    

DOI:10.1002/qre.4680040402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0748-8017    

DOI:10.1002/qre.4680040403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper reports on the results of a postal questionnaire survey of quality management methods, awareness and attitudes of suppliers to three major companies in the U.K. automotive industry. The main issues discussed include the quality management systems operated by suppliers, the methods by which quality improvement is pursued, quality‐related training, and suppliers' interaction with both their own customers and vendors.The findings to specific questions were disappointing and illustrate the poor state of quality management development in some suppliers; overall the survey evidence indicates that many suppliers have a traditional attitude towards quality management. For example: it is possible to inspect quality into a product; component quality can be graded at different levels according to individual customer requirements; if the customer does not return the product then quality must be satisfactory; the quality manager is responsible for the quality improvement programme. Quality management tools and techniques are often seen as an end in themselves rather than a means to an end, that of improvement. It is clear that a number of suppliers assume that introducing statistical process control is the same as developing a total approach to quality management. There also appears to be a dilution of the quality message as requirements are passed down the supply chain, and in general communication and feedback between customer and supplier is poo

ISSN:0748-8017    

DOI:10.1002/qre.4680040404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractDesigning reliable software is becoming an ever increasing problem because the high cost of software is largely due to reliability problems. The costs of finding and fixing the errors, better known as maintenance and testing costs, account for as much as 80 per cent of the total cost of the final software product. Software developers now have an even greater interest in preventing errors from making their way into the software and finding the errors that are present in the early stages of development. Precise software design, coding and testing play an important role. This paper presents a management plan for implementing a software reliability programme at a small software industry where no reliability programme yet exists and no reliability programme is yet established.

ISSN:0748-8017    

DOI:10.1002/qre.4680040405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractReliability improvement of CMOS VLSI circuits depends on a thorough understanding of the technology, failure mechanisms, and resulting failure modes involved. Failure analysis has identified open circuits, short circuits and MOSFET degradations as the prominent failure modes. Classical methods of fault simulation and test generation are based on the gate level stuck‐at fault model. This model has proved inadequate to model all realistic CMOS failure modes.An approach, which will complement available VLSI design packages, to aid reliability improvement and assurance of CMOS VLSI is outlined. A ‘two‐step’ methodology is adopted. Step one, described in this paper, involves accurate circuit level fault simulation of CMOS cells used in a hierarchical design process. The simulation is achieved using SPICE and pre‐SPICE insertion of faults (PSIF). PSIF is an additional module to SPICE that has been developed and is outlined in detail. Failure modes effects analysis (FMEA) is executed on the SPICE results and FMEA tables are generated.The second step of the methodology uses the FMEA tables to produce a knowledge base. Step two is essential when reliability studies of larger and VLSI circuits are required and will be the subject of a future paper. The knowledge base has the potential to generate fault trees, fault simulate and fault diagnose auto

ISSN:0748-8017    

DOI:10.1002/qre.4680040406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn his original work on the use of control charts, Shewhart distinguished between a long running known process and a new, untried process. In the latter case, the control limits are obtained from the sample data. If the process variability increases during the sampling period, the control limits will widen, reducing the sensitivity of the standard deviation and range charts and producing charts which are in control for out‐of‐control situations. Simulations were produced to investigate this problem through the eyes of the operator. Cusum procedures were used to provide the operator with a means of controlling process variability which is more sensitive to change than the control chart alone. The method was applied to data taken from an industrial situat

ISSN:0748-8017    

DOI:10.1002/qre.4680040407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper deals with an approach for choosing the proper subgroup size for control charts. The approach is particularly appropriate for batch industries where some batch‐to‐batch variation is to be expected and should be accommodated. It uses two tests to evaluate the proper subgroup sizes. The tests are ANOVA for testing that the process mean is in control and Bartlett's test for testing that the process variance is in control. Besides the two tests the width of the process from measurements based on the selected subgroup size needs to be compared with the desired specification limits. An example is included to illustrate the use of the appro

ISSN:0748-8017    

DOI:10.1002/qre.4680040408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractAn extensive analysis has been performed of life test results obtained in the long‐term (15,000 h) operation of both tungsten matrix and tungsten‐osmium matrix dispenser cathodes. Sensitive indications of potential life capability for these cathodes are shown to be available via systematic interpretation of temperature‐limited emission characteristics over time. These characteristics follow Arrhenius law temperature dependencies, with activation energies either identical with or closely similar to those determined separately for active material dispensation from these cathodes. Optimum temperature settings are determined, for each cathode type, at which projected life is maximized. Only modestly accelerated constant stress and step‐stress results yield credible reliability projections at these optimum operational temperatures. Furthermore, there remains some uncertainty concerning the application of a (time)½ dependence to all data generated in testing of the tungsten‐osmium, mixed metal matrix cathodes. Nevertheless, it is demonstrated that such cathodes can have mean lifetimes of at least 12 years, and may reach 20 years of serviceable life, sustaining only minor levels of d

ISSN:0748-8017    

DOI:10.1002/qre.4680040409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0748-8017    

DOI:10.1002/qre.4680040410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0748-8017    

DOI:10.1002/qre.4680040411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY