Fault Detection Techniques

Fault detection means to decide whether a fault has happened or not and to determine the time instant at which a fault has occurred. Fault isolation aims at finding the component in which a detected fault has occurred. Once a fault has been detected and 

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In this study, a general method to design the cheapest sensor network able to detect and locate a list of faults in a given process is proposed. The method is based on the fault detection technique proposed by Ragot and Maquin [4]. Those authors use the notion of fault sensitivity to decide whether a residual is influenced or not by a specified process fault. 

ANGHEL, L. NICOLAIDIS, M. Cost reduction and evaluation of a temporary faults detection technique. In DESIGN, AUTOMATION AND TEST IN EUROPE CONFERENCE, 2000, DATE 2000, Paris, FRA. Proceedings... New York, USA ACM Press, 2000, pp. 591-598. 

BERNARDI, L. BOLZANI, L. REBAUDENGO, M. REORDA, M. RODRIGUEZ-ANDINA, J. VIOLANTE, M. A new hybrid fault detection technique for systems-on-a-chip. IEEE Transactions on Computers, New York, USA IEEE Computer Society, 2006, v. 55, n. 2, pp. 185-198. 

In regard dynamics and control scopes, the contributions address analysis of open and closed-loop systems, fault detection and the dynamical behavior of controlled processes. Concerning control design, the contributors have exploited fuzzy and neuro-fuzzy techniques for control design and fault detection. Moreover, robust approaches to dynamical output feedback from geometric control are also included. In addition, the contributors have also enclosed results concerning the dynamics of controlled processes, such as the study of homoclinic orbits in controlled CSTR and the experimental evidence of how feedback interconnection in a recycling bioreactor can induce unpredictable (possibly chaotic) oscillations. 

Although there is a close relationship among the various quantitative model-based techniques, observer-based approaches have become very important and diffused, especially within the automatic control community. Luenberger observers [1,45, 53], unknown input observers [44], and Extended Kalman Filters [21] have been mostly used in fault detection and identification for chemical processes and plants. Reviews of several model-based techniques for FD can be found in [8, 13, 35, 50] and, as for the observer-based methods, in [1, 36,44],... 

The objective of fault detection is to determine whether the measurements remain in a normal range of values, as predicted by a process model for a given operating mode of the plant. If the difference between measurements and estimations is too large, a fault is detected. The fault detection and localization techniques are carried out in two steps the... 

In a very competitive economic context, the reliability of the production systems can be a decisive advantage. This is why, the fault detection and diagnosis are the purpose of a particular attention in the scientific and industrial community. The major idea is that the defect must not be undergone but must be controlled. Nowadays, these functions remain a large research field. The literature quotes as many fault detection and diagnosis methods as many domains of application (Venkatasubramanian, et ah, 2003). A notable number of works has been devoted to fault detection and isolation, and the techniques are generally classified as ... 

One of the most influential books on the subject of PCA was by I.T. Jolliffe [128] who published recently a new edition [129] of his book. The book by Smilde et al. [276] is the most recent contribution to the literature on multivariate statistics, with special emphasis on chemical systems. Two books coauthored by R. Braatz [38, 260] review a number of fault detection and diagnosis techniques for chemical processes. Cinar [41] coauthored a book on monitoring of batch fermentation and fault diagnosis in batch process operations. 

Hybrid Fault Tolerance Techniques to Detect Transient Faults in Embedded Processors... 

This book exposes the reasons behind the concerns surroimding a system s fault tolerance. Some of the most irrrportarrt farrlt tolerance techniques presented in the literature are analyzed arrd three novel hybrid techniques to detect farrlts in processors are presented in detail. It also covers fault injection techniques appUed to the novel techrriques, including farrlt injection by simrrlation, configuration bitstream farrlt injection, and neutron arrd Cobalt-60 beams irradiation experimerrts. 

In order to provide reliable systems that can cope with radiation effects, we believe that the solution hes in combining software-based and hardware-based techniques. The main objective of this book is finding the best trade-off between software-based and hardware-based techniques, in order to increase existing fault detection rates up to 100%, while maintaining low overheads in performance by means of operating clock frequency and application execution time, and in area by means of program and data memory overhead, and extra hardware modules. 

Following the state-of-the-art review, the next step is to implement fault tolerance techniques. We will start by explaining in detail and implementing two known software-based techniques, called Variables and Inverted Branches (AZAMBUJA 2010b), which will later be used as a complement to hybrid fault tolerance techniques. These techniques have been proposed in the past years and achieved high fault detection rates at low performance degradation levels and therefore are useful not only as an introduction to software-based fault tolerance techniques, but also to be combined with hardware-based and hybrid techniques. Then, three novel hybrid techniques will be proposed and implemented, based on both software and hardware replication characteristics. The three hybrid techniques will be divided into their software and hardware sides and described in detail, concerning both operation description and implementation. 

The book is organized as follows Chap. 2 presents the terminology and general concepts used in this work. Chapter 3 describes existing fault tolerant techniques for processors presented in the literature. Chapter 4 describes the fault tolerant techniques implemented in this work to detect transierrt fairlts in processors, from which two are known software-based and three are new lybrid techniques. Chapter 5 presents experimental fault injection campaigns for the implemented fairlt tolerarrt techniques. Chapter 6 presents the configuration bitstream fairlt injection campaign and results. Chapter 7 presents radiation experiments on some of the proposed techniques. Chapter 8 describes future work and concludes the book. 

By defining fault, error and failure, one can notice that a failure can always be seen by the user, since it leads to a system malfunction. Faults can be latent in the circuit until manifested as an error. There are detection techniques that can detect faults and there are techniques that can detect errors. 

Fault tolerance techniques aiming to detect transient effects can be mainly divided in three broad categories (1) software-based techniques, (2) hardware-based techniques and (3) l brid techniques. Fault tolerance techniques can be applied at different levels of implementation, starting from the software level down to the architecture description level, the logical and transistor level, until the layout level. In this book, we will focus on hybrid techniques applied at software level. 

J. R. Azambuja et al., Hybrid Fault Tolerance Techniques to Detect Transient Faults in Embedded Processors, DOI 10.1007/978-3-319-06340-9 3,... 

Hardware based techniques can be based on duplication with comparison, ED AC codes to protect registers and some other logical parity techniques to protect the logic. But all of them have some limitation on fault detection coverage. Without duplicating the whole processor, hardware-based techniques cannot achieve full... 

Techniques to detect data flow errors introduce overheads in memory (both program and data) and execution time, due to extra instmctions in the original code and variable and registers replicatioa On the other hand, results presented at Azambuja (2010a) have shown 100 % fault detection for all SEU and SET injected directly in... 

Techniques based on space redimdancy are grounded in the single fault model, where only one of the hardware redimdant copies is affected by transient upsets (ROSSI 2005). It means that only one of the modules will be affected by a transient fault and therefore the fault detection rate should be 100 %. On the other hand, studies have shown that a single fault may affect two hardware modules in case of SRAM-based FPGAs (KASTENSMIDT 2005) due to the routing of the architecture, or in adjacent standard cells in ASICs, as shown by Almeida (ALMEIDA 2012). 

This subsection summarizes all faults tolerant techniques mentioned in this section. Table 3.1 evaluates them according to intrusiveness, fault detection, fault correction, fault coverage and overheads in area, execution time, program memory and data memory. Classifications LOW, MEDIUM and HIGH are used when the value is not specific. 

As stated in the previous Chapters, software-based techniques are unable to detect all faults affecting the control flow, while hardware-based techniques cannot protect processors without at least doubling its area. On the other hand, combined into hybrid techniques, they can not only present increase their detection rates, but also be optimized into achieving a better tradeoff between area overhead and performance degradation, and fault detection. 

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