Savio N. Chau

Learn More
To max imize reliability of a spacecraft which perf o r m s long-life (over 10-year), deep-space mi s s ion ( to a n ou te r p lane t ) , a faul t tolerant env i ronmen t incorporating on board prevent ive ma in tenance is highly desirable. In this paper, we present a n init ial modelbased s tudy which identif ies t h e key fac tor f o r the reliability(More)
To assure dependable onboard evolution, we have developed a methodology called guarded software upgrading (GSU). In this paper, we focus on a low-cost approach to error containment and recovery for GSU. To ensure low development cost, we exploit inherent system resource redundancies as the fault tolerance means. In order to mitigate the effect of residual(More)
Cyber-physical systems (CPS) are complex net-centric hardware/software systems that can be applied to transportation, healthcare, defense, and other real-time applications. To meet the high reliability and safety requirements for these systems, proactive system health monitoring and management (HMM) techniques can be used. However, to be effective, it is(More)
This paper presents a methodology for partially reconfiguring a field programmable gate array (FPGA) device using only limited onboard resources. This paper also seeks to provide a roadmap to developing necessary tools and technologies to help design self-sufficient partial run-time reconfigurable systems for spacecraft avionic systems. To provide a vision(More)
While inherent resource redundancies in distributed applications facilitate gracefully degradable services, methods to enhance their dependability may have subtle, yet significant, performance implications, especially when such applications are stateful in nature. In this paper, we present a performability-oriented framework that enables the realization of(More)
With respect to the long-life missions associated with NASA’s X2000 Advanced Deep-Space System Development Program, reliability implies a system’s continuous operation for many years in an unsurveyed radiation-intense environment. Further, the stringent constraints on the mass of a spacecraft and the power on-board create unprecedented challenges on the(More)
ÐMessage-driven confidence-driven (MDCD) error containment and recovery, a low-cost approach to mitigating the effect of software design faults in distributed embedded systems, is developed for onboard guarded software upgrading for deep-space missions. In this paper, we first describe and verify the MDCD algorithms in which we introduce the notion of(More)
Among the COTS applications in the X2000 architecture for deep-space missions, the use of commercial bus standards is the highest-payoff COTS application since a bus interface has a global impact and enabling effect on system cost and capability, respectively. While COTS bus standards enable significant cost reductions, it is a great challenge for us to(More)