Using abstract interpretation to produce dependable aerospace control software

In the context of software dependability, the software veri- fication process has an important role. Formal verification of programs is an activity that can be inserted in this process to improve software reliability. This paper presents the defini- tion of an approach that employs a formal verification tech- nique based on abstract interpretation. The main goal is to apply this technique as a formal activity in the software veri- fication process to help software engineers identify programs faults. The applicability of the proposed approach is demon- strated by a case study based on embedded aerospace control software. The results obtained from its use show that abstract interpretation can contribute to software dependability.Fundação para a Ciência e a Tecnologia (FCT

Simulação numérica bidimensional de crescimento de ligas binárias utilizando processamento paralelo

A solidificação direcionada de ligas semicondutoras é uma das técnicas mais utilizadas para a obtenção de substratos cristalinos de alta qualidade, constituindo um protótipo de estudo de fenômenos de transporte macroscópicos envolvendo o acoplamento das equações de conservação de massa, momento e energia. As propriedades cristalinas do material obtido dependem fundamentalmente da morfologia e estabilidade da interface sólido-líquido durante o crescimento. O método numérico proposto resolve essas equações de transporte através da discretização por volumes de controle com acompanhamento da interface, e permite operar com propriedades do material e condições de contorno variáveis, incorporando detalhes do diagrama de fases da liga. Foram realizadas simulações bidimensionais de crescimento de ligas binárias utilizando malha fixa, as quais demandam processamento de alto desempenho, devido às altas resoluções temporal e espacial envolvidas. Isso levou a utilizar uma máquina multiprocessada e um multicomputador composto por 2 microcomputadores ligados em rede executando programas compilados em High Performance Fortran (HPF). ABSTRACT: The directional solidification of semiconductor alloys is an usual technique for the attainment of a high quality crystalline substratum. This technique is a prototype for the study of macrocospic transport phenomena and involves the coupling of the conservation equations for mass, moment and energy. The crystalline properties of the alloy depend basically on the morphology and stability of the solid-liquid interface during growth. The proposed numerical method solves these transport equations by discretization in control volumes with tracking of the interface. It allows for materials with variable properties and boundary conditions, and to include details of the alloy phase diagram. Two-dimensional, fixed-mesh simulations of binary alloy growth have been carried out. Due to the high spatial and temporal resolutions, these simulations were run on a multiprocessed machine and on a multicomputer composed by a cluster of two microcomputers. The programs were compiled in High Performance Fortran (HPF).Number of Pages: 11

Formal verification with Frama-C: a case study in the space software domain

With the increasing importance of software in the aerospace field, as evidenced by its growing size and complexity, a rigorous and reliable software verification and validation process must be applied to ensure conformance with the strict requirements of this software. Although important, traditional validation activities such as testing and simulation can only provide a partial verification of behavior in critical real-time software systems, and thus, formal verification is an alternative to complement these activities. Two useful formal software verification approaches are deductive verification and abstract interpretation, which analyze programs statically to identify defects. This paper explores abstract interpretation and deductive verification by employing Frama-C's value analysis and Jessie plug-ins to verify embedded aerospace control software. The results indicate that both approaches can be employed in a software verification process to make software more reliable.This work was supported in part by the Brazilian Space Agency under Grant 20VB.info:eu-repo/semantics/publishedVersio