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Evans, Carol

Publications and source records attributed to Evans, Carol.

The Parachute System Recovery of the Orion Pad Abort Test 1

The Orion Pad Abort Test 1 was conducted at the US Army White Sands Missile range in May 2010. The capsule was successfully recovered using the original design for the parachute recovery system, referred to as the CEV Parachute Assembly System (CPAS). The CPAS was designed to a set of requirements identified prior to the development of the PA-1 test; these requirements were not entirely consistent with the design of the PA-1 test. This presentation will describe the original CPAS design, how the system was modified to accommodate the PA-1 requirements, and what special analysis had to be performed to demonstrate positive margins for the CPAS. The presentation will also discuss the post test analysis and how it compares to the models that were used to design the system.

Machin, Ricardo↗

Editing wild points in isolation - Fast agreement for reliable systems (Preliminary version)

Consideration is given to the intuitively appealing notion of discarding sensor values which are strongly suspected of being erroneous in a modified approximate agreement protocol. Approximate agreement with editing imposes a time bound upon the convergence of the protocol - no such bound was possible for the original approximate agreement protocol. This new approach is potentially useful in the construction of asynchronous fault tolerant systems. The main result is that a wild-point replacement technique called t-worst editing can be shown to guarantee convergence of the approximate agreement protocol to a valid agreement value. Results are presented for a four-processor synchronous system in which a single processor may be faulty.

Kearns, Phil↗