04:00 - 04:20

• Dynamic Safety Cases for Through-Life Safety Assurance

  We describe dynamic safety cases, a novel operationalization of the concept of through-life safety assurance, whose goal is to enable proactive safety management. Using an example from the aviation systems domain, we motivate our approach, its underlying principles, and a lifecycle. We then identify the key elements required to move towards a formalization of the associated framework.

Ewen Denney; Ibrahim Habli; Ganesh Pai

SGT, USA; Nasa Ames, USA; University of York, UK

04:20 - 04:40

• Correctness and Relative Correctness

  In the process of trying to define what is a software fault, we have found that to formally define software faults we need to introduce the concept of relative correctness, i.e. The property of a program to be more-correct than another with respect to a given specification. A feature of a program is a fault (for a given specification) only because there exists an alternative to it that would make the program more-correct with respect to the specification. In this paper, we explore applications of the concept of relative correctness in program testing, program repair, and program design. Specifically, we argue that in many situations of software testing, fault removal and program repair, testing for relative correctness rather than absolute correctness leads to clearer conclusions and better outcomes. Also, we find that designing programs by stepwise correctness-enhancing transformations rather than by stepwise correctness-preserving refinements leads to simpler programs and is more tolerant of designer mistakes.

Nafi Diallo; Wided Ghardallou; Ali Mili

New Jersey Institute of Technology, USA; University of Tunis El Manar, Tunisia

04:40 - 05:00

• On Architectural Diversity of Dynamic Adaptive Systems

  We introduce a novel concept of "architecture diversity" for adaptive systems and posit that increased diversity has an inverse correlation with adaptation costs. We propose an index to quantify diversity and a static method to estimate the adaptation cost, and conduct an initial experiment on an exemplar cloud-based system which reveals the posited correlation.

   

  Preprint available:

Hui Song; Amal Elgammal; Vivek Nallur; Franck Chauvel; Franck Fleurey; Siobhan Clarke

SINTEF ICT, Norway; Trinity College Dublin, Ireland

05:00 - 05:10

• Information Transformation: An Underpinning Theory for Software Engineering

  Software engineering lacks underpinning scientific theories both for the software it produces and the processes by which it does so. We propose that an approach based on information theory can provide such a theory, or rather many theories. We envision that such a benefit will be realised primarily through research based on the quantification of information involved and a mathematical study of the limiting laws that arise. However, we also argue that less formal but more qualitative uses for information theory will be useful. The main argument in support of our vision is based on the fact that both a program and an engineering process to develop such a program are fundamentally processes that transform information. To illustrate our argument we focus on software testing and develop an initial theory in which a test suite is input/output adequate if it achieves the channel capacity of the program as measured by the mutual information between its inputs and its outputs. We outline a number of problems, metrics and concrete strategies for improving software engineering, based on information theoretical analyses. We find it likely that similar analyses and subsequent future research to detail them would be generally fruitful for software engineering.

David Clark; Robert Feldt; Simon Poulding; Shin Yoo

University College London, UK; Blekinge Institute of Technology, Sweden