This paper presents an overview of NASA Langley's research program in formal methods. The major goals of this work are to make formal methods practical for use on high integrity systems, to orchestrate the transfer of this technology to U.S. industry through use of carefully designed demonstration projects, and to exploit this technology to help achieve… (More)
it happens all the time. Beyond errors of distraction, no less a logician than Aristotle knew that in the real world even the most careful reasoning about a simple sentence can lead to the wrong conclusion. In programming, our conditional thoughts reach a logical complexity that Aristotle could not have imagined, nor likely condoned. Every day thousands of… (More)
Mishap investigations provide important information about adverse events and are intended to help avoid any recurrence of previous failures. However, the complexity of many safety critical systems poses new challenges for mishap analysis. Similarly, the recognition that many failures have complex, systemic causes has helped to widen the scope of many mishap… (More)
The activity-regulated-cytoskeletal-associated protein (Arc) has a well established role in memory consolidation and synaptic plasticity in the hippocampus and amygdala. However the role of Arc within the anterior cingulate cortex (ACC), an area of the brain involved in processing memory for pain, has yet to be examined. Here we sought to determine if Arc… (More)
Met ne of the most challenging tasks in software system design is to assure reliability, especially as these systems are increasingly used 0 in sensitive and often life-critical environments such as medical systems, air traffic control, and space applications. It is therefore essential for developers to employ those methods that offer a high degree of… (More)
This paper presents a logical analysis of a typical argument favoring the use of formal methods for software development, and suggests an alternative argument that is simpler and stronger than the typical one.
This working paper presents preliminary ideas of five possible text-based notations for representing safety cases, which may be easier for non-graphically inclined people to use and understand than the currently popular graphics-based representations.
For many years, NASA Langley Research Center has cooperated with the Federal Aviation Administration (FAA) in research about software engineering methods for aerospace applications. Recent research has focused on software aspects of the FAA's certification process. In this paper, the results of the Streamlining Software Aspects of Certification (SSAC)… (More)
System safety professionals, both researchers and practitioners, who regularly read accident reports reap important benefits. These benefits include an improved ability to separate myths from reality, including both myths about specific accidents and ones concerning accidents in general; an increased understanding of the consequences of unlikely events,… (More)