VM Migration for Autonomic Fault Tolerance provides the continuous availability for applications in the event of virtual machine failures along with the benefits of improved performance and manageability. Multipath correlation coefficient approach for VM migration has been proposed, which takes into account the overutilization of CPU without performance degradation based on work variability. Th...

We address the problem of how to integrate fault-tolerant external and internal clock synchronization. In this paper we propose a new external/internal clock synchronization algorithm which provides both external and internal clock synchronization for as long as a majority of the reference time servers (servers with access to reference time) stay correct. When half or more of the reference time...

The reliability data obtained from the field shows significant deviation from the expectation, especially from those obtained from reliability modelling. This hints that a more acurate model should be employed in the evaluation. A detailed model incorporating a transient fault in the form of hardware-software interaction offers a solution to this problem.

A method for single hard fault detection in linear analog circuits based on simulation before testing approach is proposed in this paper. Simulation before testing approach locates or identifies faulty components of the circuit under test (CUT) by creating a fault dictionary for all the potentially faulty components from the simulation of CUT. In the proposed approach, the CUT is simulated usin...

It has become well-established that software will never become bug-free, which has spurred research in mechanisms to contain faults and recover from them. Since such mechanisms deal with faults, fault injection is necessary to evaluate their effectiveness. However, little thought has been put into the question whether fault injection experiments faithfully represent the fault model designed by ...

This two-part paper focuses on the modeling and diagnosis of multistage manufacturing processes. Part I develops a state space model characterizing variation propagation in a multistage process. The state space model describes a discrete-time LTV (Linear Time Varying) stochastic system, which strongly indicates that the existing system and control theory could be used to perform systematic anal...

We develop a case breach model for the on-board fault diagnostics and prognostics system for subscale solid-rocket boosters (SRBs). The model development was motivated by recent ground firing tests, in which a deviation of measured time-traces from the predicted time-series was observed. A modified model takes into account the nozzle ablation, including the effect of roughness of the nozzle sur...

This article presents a robust and computationally inexpensive technique of component-level fault detection in aircraft gas-turbine engines. The underlying algorithm is based on a recently developed statistical pattern recognition tool, symbolic dynamic filtering (SDF), that is built upon symbolization of sensor time series data. Fault detection involves abstraction of a language-theoretic desc...

Conventional schemes of fast valving generate a fixed valve stroke sequence for the control of turbine valves under transient conditions. A simple fixed valve control sequence cannot give optimum result for different fault conditions and loading levels, due to its poor adaptability. This paper presents an artificial-neuralnetwork (ANN) based controller to govern the operation of the turbine con...

This paper considers detectability of deviation of sensors from their nominal behavior for a class of linear time-invariant discrete-time systems in the presence of bounded additive uncertainties. Detectable sensor faults using interval observers are analyzed considering two distinct approaches: invariant-sets and classical fault-sensitivity method. It can be inferred from this analysis that bo...