This report describes a continuing research effort in software reliability which was first reported in 'System Test Methodology, ' Naval Postgraduate School, Vol I NPS55SS75072A, Vol. II NPS 55SS75072B (1975). The work just completed involved: improvement of the software error simulation model; validation of the software error simulation model; and analysis of program complexity with simulation and analytical models, using 44 Naval Tactical Data System procedures. The results which were achieved are the following: (1) all validation tests were passed; however simulation results were generally higher than analytical results and (2) the general direction of the relationship between complexity measures and error detection was as expected; however, considerable variability was exhibited when single independent variables were used. It appeared that a multivariable model involving error detection and several program complexity measures would be more appropriate. (Author).

A model of the error detection process for the testing of software has been developed to investigate the relationship between computer program structure and error detection and test effort. The model has been implemented as a simulation.

The objective of this study was to develop a parsimonious model whose parameters have a physical interpretation, and which can be used to predict various quantitative measures for software performance assessment. With this objective, the behavior of the software failure counting process (N(t), t equal to or greater than zero) has been studied. It is shown that N(t) can be well described by a non-homogeneous Poisson process (NHPP) with a two parameter exponentially decaying error detection rate. Several measures, such as the number of failures by some prespecified time, the number of errors remaining in the system at a future time, and software reliability during a mission, have been proposed in this report. Models for software performance assessment are also derived. Two methods are developed to estimate model parameters from either failure count data or times between failures. A goodness-of-fit test is also developed to check the adequacy of the fitted model. Finally, actual failure data are analyzed from two DOD software systems. One is a large command and control system and the other a Naval data analysis system. (Author).

Software Quality Control, Error, Analysis

Software Quality Control, Error, Analysis

Since 1995, when the SPIN workshop series was instigated, SPIN workshops have been held on an annual basis in Montr ́ eal (1995), New Brunswick (1996), Enschede (1997), Paris (1998), Trento (1999), Toulouse (1999), Stanford (2000), Toronto (2001), Grenoble (2002) and Portland (2003). All but the ?rst SPIN workshop were organized as satellite events of larger conferences, in particular of CAV (1996), TACAS (1997), FORTE/PSTV (1998), FLOC (1999), the World Congress on Formal Methods (1999), FMOODS (2000), ICSE (2001, 2003) and ETAPS (2002). This year again, SPIN was held as a satellite event of ETAPS 2004. The co-location of SPIN workshops with conferences has proven to be very successful and has helped to disseminate SPIN model checking technology to wider audiences. Since 1999, the proceedings of the SPIN workshops have appeared in Springer-Verlag’s Lecture Notes in Computer Science series. The history of successful SPIN workshops is evidence for the maturing of model checking technology, not only in the hardware domain, but increasingly also in the software area. While in earlier years algorithms and tool development aroundtheSPINmodelcheckerwerethefocusofthisworkshopseries,forseveral years now the scope has been widened to include more general approaches to software model checking techniques and tools as well as applications. The SPIN workshop has become a forum for all practitioners and researchers interested in model checking based techniques for the validation and analysis of communication protocols and software systems.