William Nace

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We present a framework that will enable scalable analysis and design of graceful degradation in distributed embedded systems. We define graceful degradation in terms of utility. A system that gracefully degrades suffers a proportional loss of system utility as individual software and hardware components fail. However, explicitly designing a system to(More)
It has long been a tenet of the fault-tolerance research community that fault– tolerance is possible by exploiting resource redundancy in order to achieve the mission result. Hardware designers, for instance, rely upon various forms of redundant hardware to ensure the availability of at least one system that can produce correct responses. Strangely, one(More)
As embedded systems become more distributed they provide more flexibility, the potential for greater functionality, and, unfortunately, more pieces to break. But what if there were a way to turn this proliferation of small processors into a reliability asset instead of vulnerability? What if when one component broke, the rest of the system kept working with(More)
INTRODUCTION Long-term trends in aircraft crash rates are of interest to researchers in aerospace medicine, the acquisition community, the aircraft industry, and the flying public. METHODS Data were obtained from the USAF Safety Center database for all major accidents (Class A Mishaps) and for annual flight hours for fiscal years 1950 through 2006.(More)
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