NASA plans innovative and novel approaches to future (unmanned) space exploration missions. Future missions involve sending spacecraft and robots to harsh environments, where resilience is necessary for the survival of the mission. In addition, distances and communication lead times between the spacecraft and Earth necessitate much of the mission operation being autonomous. We have been conduct...

A reconngurable fault tolerant system achieves the attributes of dependability of operations through fault detection, fault isolation and reconnguration, typically referred to as the FDIR paradigm. Fault diagnosis is a key component of this approach, requiring an accurate determination of the health and state of the system. An imprecise state assessment can lead to catastrophic failure due to a...

Abstract. This paper presents a system, Loopy, for programming loop transformations. Manual loop transformation can be tedious and errorprone, while fully automated methods do not guarantee improvements. Loopy takes a middle path: a programmer specifies a loop transformation at a high level, which is then carried out automatically by Loopy, and formally verified to guard against specification a...

This technical report describes our progress towards a formally verified version of the Nuprl Proof Assistant. We define a deep embedding of most of Nuprl into Coq. Among others, it includes a nominal-style definition of the Nuprl language, reduction rules, a coinductively defined computational equivalence, and the curry-style type system where types are defined as partial equivalence relations...

Recent advances in hardware design have demonstrated mechanisms allowing a wide range of low-level security policies (or micro-policies) to be expressed using rules on metadata tags. We propose a methodology for defining and reasoning about such tag-based reference monitors in terms of a high-level “symbolic machine,” and we use this methodology to define and formally verify micro-policies for ...