Ftcs

Design diversity has long been known to protect redundant systems against common-mode failures. In this paper, for the first time, we present a metric to quantify diversity among several designs. Based on this metric, we derived analytical reliability models that show a simple relationship between design diversity, system failure rate, and mission time. In addition, we also present simulation results to demonstrate the effectiveness of design diversity in duplex and Triple Modular Redundant (TMR) systems. For independent multiple-module failures, both the analytical and simulation results show that there is no obvious advantage of using diversity in redundant systems. However, for common-mode failures, there is a significant gain in using diversity — however, the gain diminishes as the mission time increases. For a particular example, if the mission time goes down by a factor of 10, the reliability of a diverse system improves by more than a factor of 4 over a non-diverse system. Fi...

Fault-tolerant distributed systems based on field-buses may take advantage from reliable and atomic broadcast. There is a current belief that CAN native mechanisms provide atomic broadcast. In this paper, we dismiss this misconception, explaining how network errors may lead to: inconsistent message delivery; generation of message duplicates. These errors may occur when faults hit the last two bits of the end of frame delimiter. Although rare, its influence cannot be ignored, for highly fault-tolerant systems. Finally, we give a protocol ...

Input-data and hardware fault-tolerance of neural networks are discussed. It is shown that fault-tolerance behavior is not self-evident but must be activated by an appropriate learning scheme. Practical limitations are demonstrated by an exam-ple of neural character ...

It has been proposed to conduct a test of a software safety system for a nuclear reactor by subjecting it to demands that are statistically representative of those it will meet in operational use. The intention behind the test is to acquire a high confidence (99%) that the probability of failure on ...

Considering an application in which processes take local checkpoints independently (called basic checkpoints), this paper develops a protocol that forces them to take some additional local checkpoints (called forced checkpoints) in order that the resulting checkpoint and communication pattern satisfies the Rollback Dependency Trackability (RDT) property. This property states that all dependencies between local checkpoints are on-line trackable by using a transitive dependency vector. Compared to other protocols ...

Mixed analog and digital mode simulators have been available for accurate transient fault simulation. However, they are not fast enough to simulate a large number of transient faults on a relatively large circuit in a reasonable amount of time. The authors describe a gate-level transient fault simulation environment which has been developed based on realistic fault models. The simulation environment uses a timing fault simulator as well as a zero-delay parallel fault simulator. The timing fault simulator uses high level models of the actual transient fault phenomenon and latch operation to accurately propagate the fault effects to the latch outputs, after which point the zero-delay parallel fault simulator is used to speed up the simulation without any loss in accuracy. The simulation environment is demonstrated on ISCAS-89 sequential benchmark circuits.