Intermittent Failure Dynamics Characterization

Abstract

Heart failure constitutes a major public health problem worldwide. Affected patients experience a number of changes in the electrical function of the heart that predispose to potentially lethal cardiac arrhythmias. Due to the multitude of electrophysiological changes that may occur during heart failure, the scientific literature is complex and sometimes ambiguous, perhaps because these findings are highly dependent on the etiology, the stage of heart failure, and the experimental model used to study these changes. Nevertheless, a number of common features of failing hearts have been documented. Prolongation of the action potential (AP) involving ion channel remodeling and alterations in calcium handling have been established as the hallmark characteristics of myocytes isolated from failing hearts. Intercellular uncoupling and fibrosis are identified as major arrhythmogenic factors. Multi-scale computational simulations are a powerful tool that complements experimental and clinical research. The development of biophysically detailed computer models of single myocytes and cardiac tissues has contributed greatly to our understanding of processes underlying excitation and repolarization in the heart. The electrical, structural, and metabolic remodeling that arises in cardiac tissues during heart failure has been addressed from different computational perspectives to further understand the arrhythmogenic substrate. This review summarizes the contributions from computational modeling and simulation to predict the underlying mechanisms of heart failure phenotypes and their implications for arrhythmogenesis, ranging from the cellular level to whole-heart simulations. The main aspects of heart failure are presented in several related sections. An overview of the main electrophysiological and structural changes that have been observed experimentally in failing hearts is followed by the description and discussion of the simulation work in this field at the cellular level, and then in 2D and 3D cardiac structures. The implications for arrhythmogenesis in heart failure are also discussed including therapeutic measures, such as drug effects and cardiac resynchronization therapy. Finally, the future challenges in heart failure modeling and simulation will be discussed.

The Challenge of Detection and Diagnosis of Fugacious Hardware Faults in VLSI Designs

“…Other examples of can be found in certain cruise control modules for vehicles [14] which hit a return rate of 96% due to undetected intermittent failures. These figures can be uneven depending on the context of operation since, as distinguished by Savir [15], random originated intermittent faults appear and disappear in an unpredictable fashion whether systematic intermittent faults evolution can be numerically characterized [16]. This enables a proper decision on the best moment to apply recovery actions to maximise availability.…”

A Carrier Signal Approach for Intermittent Fault Detection and Health Monitoring for Electronics Interconnections System

“…If these are not detected on time or at the early stage, it would gradually lead to permanent fault and are also safety critical [1]. This also lead to, many other problems for example delayed or cancellation of flights, electrical arc or spark that could lead disaster that progressed from IFs.…”

New Fault Detection, Mitigation and Injection Strategies for Current and Forthcoming Challenges of HW Embedded Designs

“…Some of them only take place during temporary periods and later disappear -transient faultswhile others can only appear but never stop their unwelcome effect -permanent faults [13]. Moreover, there is a special type of faults which appear and disappear at random instants of time, i. e. they manifest themselves intermittently -the intermittent faults [34,37]. These intermittent manifestations in the same location can be due to operational circumstances, which may eventually disappear, or be caused by wearout processes or manufacture defects.…”

“…Much effort has been later put in properly diagnosing intermittent faults, as differentiated from isolated transient faults [22,37]. It is not a trivial problem, which is dealt at the lowest level hardware in some solutions and at higher level controllers in others.…”

“…Other examples of can be found in certain cruise control modules for vehicles [96] which hit a return rate of 96% due to undetected intermittent failures. These figures can be uneven depending on the context of operation since, as distinguished by Savir [152], random originated intermittent faults appear and disappear in an unpredictable fashion whether systematic intermittent faults evolution can be numerically characterized [37]. This enables a proper decision on the best moment to apply recovery actions to maximise availability.…”