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Avionics Testing
18
World Abstracts on Microelectronics and Reliability
operational tests, and tested reliability, two years later, were at variance. Accordingly, after a six-months investigation, the Navy embarked on a modification program. At the heart of the program was a continuity of lines approach in lieu of the widely advocated "fly-before-buy" approach. Subsequent analysis indicates significant advantages of the former approach.
Optimal maintenance policy for systems that experience state degmdafiom. C. L. PROCTOR and Y. T. WANG. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 199. The states of the system studied consist of good (state 0), degraded (states 1, 2 . . . . . n - 1) and failed (state n). Renewal theory was used to obtain the hazard rate of the system with the assumption that the transition rate from one state to the next (including the failure state) is equal at any state. An optimal preventive maintenance policy was obtained by maximizing the availability of the system, i.e. the fractional amount of the up-time over a long total time interval.
Quality Progress p. 13 (June 1975). The following factors affect the choice of an AQL: (1) Balance between desired quality and an attainable quality level. (2) Review of past performance of a supplier. (3) Classification of defects, i4t Effect of nonconforming product on later processing or assembling. (5) Complaints from the field (customer complaints). (6) Tactical or design requirements. (7) Cost to attain the AQL. Avionics Testing, LT. COL. BEN. H. SWE'IT. Proc. Relia: bility and Maintainability Symposium. 28-30 January, 1975. Washington D.C.p. 86. The time and cost involved in testing avionics subsystems and equipment can be dramatically reduced, without sacrificing field reliability or statistical confidence in the test results, by combining present performance, environmental and reliability test programs. The concept of integrated performance, environmental and reliability testing hinges on empirical development of environmental K factors for various test conditions. Air Force Systems Command is moving to validate and implement this new concept.
An optimising technique tor a K-out-of-N system. A. H. K. LING and A. A. P. DE SOUZA. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 217. Of the class of redundant configuration systems the Kout-of-N system is studied. The system is considered successful if at least K subsystems out of the N are successful. A technique based on Bellman's "Principle of Optimality" is developed to optimise the system reliability subject to cost constraints.
PBX maintenance comes wrapped in a new package. JOHN D: WIDAKAS. Bell Laboratories Record. p. 301 (July/Aug. 1975). Newly developed tools, documents, training, and administrative methods for maintaining the 800A and 801A PBX systems permit craft personnel to achieve greater effectiveness, accuracy, and speed in their work.
Optimbation of a K-on-N configuration. D. HONKANEN and A. A. P. DE SOUZA. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 223. A new class of redundant systems called the K-on-N configuration is introduced here. Realistic design features are developed for the available resources to build a highly reliable system. An easily programmed algorithm due to Lawler and Bell is adapted to solve the optimization problem. The method is applied for reliability improvement of a real-life system problem.
Reliability esfim_a_tion and sensitivity testing, ROBERrl~ (3. EASTERLING. Proc. I975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 141. Reliability requirements are sometimes expressed as that at a particular stress level, say Xo, the failure probability of a device should not exceed P0. Considered here are the collection and statistical analysis of data by which one can assess whether the requirement is met. Testing at selected stress levets additional to x0 is studied and both destructive and non-destructive testing are considered.
Software reliability, how it affects system reliability. JAMES A. RONBACK. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 121. This paper suggests that there is an additional measurable attribute, system "structuredness" which contributes to system reliability. It examines the effect of the structure of software on the integrity of a system. It shows how intuition fails us when we accept a less hierarchally structured system and expect it to behave as reliably. "Structuredness", can be used together with the system availability figure to provide a realistic measure of system integrity. The results of implementing structured programming techniques to increase software reliability are briefly discussed.
The design error c o n ~ u t i o n to failure. JOHN A. ROaERTS. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 159. This paper describes a practical approach to improving the reliability of electronic equipment. Recognizing that unreliable, untestable and unmaintainable equipment can be built with high grade reliable components, several approaches are suggested to improve designer performance. Methods include education programs, communication improvements, checklists, design handbooks and design review methods.
Practical method of computing product contormance quality cost. D. B. N. MURTHY. QR Journal, India p. 87 (May 1975). Quality costs can add substantial amount to the total cost of a product. Hence, it is necessary to know the Quality Costs separately. This paper gives a practical method of estimating the product conformance Quality Cost from the various elements associated with the cost. A Quality Cost Index (QCI) is derived which can be used by management as a guide and to allocate funds for strengthening Preventive and Appraisal functions. This in turn will bring down the Failure costs and hence the total Quality Cost. Specifying AQLs and LOs in p r ~ e n t documents. Some basic Guidelines ior ~ MIL.STD-10$D to the QA provisions o| part specifications. PAUL J. HOGAN.
LCC--Commercial Application. Ten years of iih cycle eo~llg. DONALD R. EARLES. Proe. Reliability and Main, tainability Symposium. 28-30 January 1975. Washington D.C.p. 74. Over the past ten years, Life Cycle Costing has evolved into four things; a costing discipline, a procurement technique, an acquisition consideration, and a design trade-off tool. As a costing technique, it has primarily been concerned with operating and support cost estimating. As a procurement technique, it has been used as a cost per usage determination. As an acquisition consideration, it is concerned with the balancing of acquisition and ownership costs. As a design trade-off tool. its concern has been with the impact o f specific design features on operating and support costs, and of repair determinations and operating and maintenance policy. This paper reviews its development, looks at its structuring and cost estimating techniques, assesses applications on different types of programs and program phases, and assesses results of applications to date.
World Abstracts on Microelectronics and Reliability
operational tests, and tested reliability, two years later, were at variance. Accordingly, after a six-months investigation, the Navy embarked on a modification program. At the heart of the program was a continuity of lines approach in lieu of the widely advocated "fly-before-buy" approach. Subsequent analysis indicates significant advantages of the former approach.
Optimal maintenance policy for systems that experience state degmdafiom. C. L. PROCTOR and Y. T. WANG. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 199. The states of the system studied consist of good (state 0), degraded (states 1, 2 . . . . . n - 1) and failed (state n). Renewal theory was used to obtain the hazard rate of the system with the assumption that the transition rate from one state to the next (including the failure state) is equal at any state. An optimal preventive maintenance policy was obtained by maximizing the availability of the system, i.e. the fractional amount of the up-time over a long total time interval.
Quality Progress p. 13 (June 1975). The following factors affect the choice of an AQL: (1) Balance between desired quality and an attainable quality level. (2) Review of past performance of a supplier. (3) Classification of defects, i4t Effect of nonconforming product on later processing or assembling. (5) Complaints from the field (customer complaints). (6) Tactical or design requirements. (7) Cost to attain the AQL. Avionics Testing, LT. COL. BEN. H. SWE'IT. Proc. Relia: bility and Maintainability Symposium. 28-30 January, 1975. Washington D.C.p. 86. The time and cost involved in testing avionics subsystems and equipment can be dramatically reduced, without sacrificing field reliability or statistical confidence in the test results, by combining present performance, environmental and reliability test programs. The concept of integrated performance, environmental and reliability testing hinges on empirical development of environmental K factors for various test conditions. Air Force Systems Command is moving to validate and implement this new concept.
An optimising technique tor a K-out-of-N system. A. H. K. LING and A. A. P. DE SOUZA. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 217. Of the class of redundant configuration systems the Kout-of-N system is studied. The system is considered successful if at least K subsystems out of the N are successful. A technique based on Bellman's "Principle of Optimality" is developed to optimise the system reliability subject to cost constraints.
PBX maintenance comes wrapped in a new package. JOHN D: WIDAKAS. Bell Laboratories Record. p. 301 (July/Aug. 1975). Newly developed tools, documents, training, and administrative methods for maintaining the 800A and 801A PBX systems permit craft personnel to achieve greater effectiveness, accuracy, and speed in their work.
Optimbation of a K-on-N configuration. D. HONKANEN and A. A. P. DE SOUZA. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 223. A new class of redundant systems called the K-on-N configuration is introduced here. Realistic design features are developed for the available resources to build a highly reliable system. An easily programmed algorithm due to Lawler and Bell is adapted to solve the optimization problem. The method is applied for reliability improvement of a real-life system problem.
Reliability esfim_a_tion and sensitivity testing, ROBERrl~ (3. EASTERLING. Proc. I975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 141. Reliability requirements are sometimes expressed as that at a particular stress level, say Xo, the failure probability of a device should not exceed P0. Considered here are the collection and statistical analysis of data by which one can assess whether the requirement is met. Testing at selected stress levets additional to x0 is studied and both destructive and non-destructive testing are considered.
Software reliability, how it affects system reliability. JAMES A. RONBACK. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 121. This paper suggests that there is an additional measurable attribute, system "structuredness" which contributes to system reliability. It examines the effect of the structure of software on the integrity of a system. It shows how intuition fails us when we accept a less hierarchally structured system and expect it to behave as reliably. "Structuredness", can be used together with the system availability figure to provide a realistic measure of system integrity. The results of implementing structured programming techniques to increase software reliability are briefly discussed.
The design error c o n ~ u t i o n to failure. JOHN A. ROaERTS. Proc. 1975 Canadian SRE Reliability Symposium. May 10th. Ottawa. p. 159. This paper describes a practical approach to improving the reliability of electronic equipment. Recognizing that unreliable, untestable and unmaintainable equipment can be built with high grade reliable components, several approaches are suggested to improve designer performance. Methods include education programs, communication improvements, checklists, design handbooks and design review methods.
Practical method of computing product contormance quality cost. D. B. N. MURTHY. QR Journal, India p. 87 (May 1975). Quality costs can add substantial amount to the total cost of a product. Hence, it is necessary to know the Quality Costs separately. This paper gives a practical method of estimating the product conformance Quality Cost from the various elements associated with the cost. A Quality Cost Index (QCI) is derived which can be used by management as a guide and to allocate funds for strengthening Preventive and Appraisal functions. This in turn will bring down the Failure costs and hence the total Quality Cost. Specifying AQLs and LOs in p r ~ e n t documents. Some basic Guidelines ior ~ MIL.STD-10$D to the QA provisions o| part specifications. PAUL J. HOGAN.
LCC--Commercial Application. Ten years of iih cycle eo~llg. DONALD R. EARLES. Proe. Reliability and Main, tainability Symposium. 28-30 January 1975. Washington D.C.p. 74. Over the past ten years, Life Cycle Costing has evolved into four things; a costing discipline, a procurement technique, an acquisition consideration, and a design trade-off tool. As a costing technique, it has primarily been concerned with operating and support cost estimating. As a procurement technique, it has been used as a cost per usage determination. As an acquisition consideration, it is concerned with the balancing of acquisition and ownership costs. As a design trade-off tool. its concern has been with the impact o f specific design features on operating and support costs, and of repair determinations and operating and maintenance policy. This paper reviews its development, looks at its structuring and cost estimating techniques, assesses applications on different types of programs and program phases, and assesses results of applications to date.