moncler doudoune Quantitative discussion of softwa

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Quantitative discussion of software reliability

Polynomial rooting problem. F (z) is theoretically a 1 k roots. A factor based on the change from negative to positive law,[link widoczny dla zalogowanych], know that F (z) there must exist a real root; find F (z) of the first derivative dF / dx, in F (z) and dF / dx for Zhanzhuan between known division between the two common factors not containing the SC,[link widoczny dla zalogowanych], so know the differential calculus, the F (z) there is no repeated roots; as z continues to increase, because F (z) for the higher order polynomial, Mathematics will quickly tend to overflow. It can be seen F (z) the removal of a real root outside, while the remainder are pseudo-root can be ignored. By the variable step successive approximation method easy to get roots 2C, thus can solve for estimates of parameters a, Zhan. estimated failure rate at time t is (tk) a Xexp (- X £) (6) t time the estimated value of 7O spacecraft MTBF process 16 MTBF (t) a (t) (7) No loss of software failure, so the time is different from the hardware, software, the task of the task time. Software to perform the actual task, the software undergo a full mission profile of the software cycle time can be considered as the task time. Time set of software tasks T, the task of the software reliability estimate is R (D) a exp [a A () x D] (8) 5.2 Example of a subsystem of a large computer software, software testing platform to do the whole mission profile from the test case for a long time under the verification test, found a fix and then test after a failure in a timely manner, failure times were recorded as D l6. (Hall) (the literature [3],[link widoczny dla zalogowanych], P.158 gives results only), the software implementation of a full mission profile is about the history of D 2h, try the software estimates the average time between failures MTBF and reliability R. Solutions run the R55. exe, gives the following results: l software testing the reliability of the information of the S-H model of treatment l, enter: the number of nodes K, in ascending order of failure time (), i a 1, K and D K-time software tasks 16t () a 1,2.3,8,12,36,42,56,89,90, l20, 142,155,177,254,261 (h) T-2 () result information: SearchTimes a 59RootX = 0 .99105 D +00 F (X) 0-0.13228D-03Alpha a 0.14066D + OOBeta a 0.89917I) _02Lamda (261) a 0.13457 anal 01MTBF (261) a 0.74310D +02 R (2) 10. 9734D +00 its calculation and the literature 1-3] the results were in agreement. 6 Conclusion In this article, stars on the big and medium-sized computer software reliability assessment indicators established a target value, and reliability of computer hardware in general the same; with the principles of statistical sampling to verify the software MTBF is given a pilot program for choice; also pointed out that the software before delivery of the assessment under the MTBF Confidence Limits. This paper emphasizes the software with test cases as much to do random testing, using test data accumulated to speak, to assess the reliability of the software, qualitative analysis from the past have gradually shifted the quantitative analysis and verification. How to set up and improved the whole mission profile test case under the platform of the computer assessment, is the key and difficult. It depends on a deep understanding of the needs of satellite missions depends on the accumulation of experience in software programming,[link widoczny dla zalogowanych], but also on the special requirements of satellite monitoring methods. Software testing platform for the development needs of a long-term process of accumulation, it can not be parked to products only through professional contacts within and outside the space,[link widoczny dla zalogowanych], go th my development.
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