Perceived fault

The ISO 26262 introduces the term of a perceived fault , but does so in a different context (in the context of perceiving latent faults In a technical systems, that have no diagnostic mechanism, but are perceivable by the driver, e.g. by a strange noise). The term perceived fault must not be misused in the context of hazard classification, simply assuming that a failure of a CMS, as soon as sit Is perceived by the user, is safe (a drastic example drivers would certainly perceive It when their steering wheel is blocked due to some technical fault, but nevertheless, would have few possibilities of avoiding an accident in this situation.). 

However, for structuring to have some direct relevance to questions of operational dependability, and in particular fault tolerance, it must be what might be described as strong—strong structuring actually controls interactions within and between systems, and limits error propagation in both time and space, i.e., constitutes real not just perceived or imagined boundaries. 

Fault seal has not been perceived to be a problem in the Heidrun Field (Hemmens et al., 1994) but elsewhere in the Greater Heidrun area it is considered one of the key controls on migration, trap filling and trap integrity. A key part of the structural analysis of... 

As a result, through these equations we have a way to calculate the intangible costs as consequence of a customer complain due to an incident or fault related to maintenance of the service. But in the sector of DNSPs where contracts and standards spin aroimd of service level agreements (SLAs), it would have to align the estimated costs with these service features. This is because the quality measured has to be the perceived and demanded quality by the customer and not fix>m internal performance the costs have to reflect the price of nonperformance (Crosby, 1979). 

This newly established ISARCS symposium provided an exclusive forum for exchanging views on the theory and practice for architecting critical systems. Such systems are characterized by the perceived severity of consequences that faults or attacks may cause, and architecting them requires appropriate means to assure that they will fulfill their specified services in a dependable and secure manner. 

Many analysts have subsequently faulted NASA for missing the implications of the 0-ring data (Tufte, 1997 Vaughan, 1996). Yet the engineers and scientists at NASA were tracking thousands of potential risk factors. It was not that some system behaviors had come to be perceived as normal, but rather that some behaviors outside the normal or expected range had come to be seen as acceptable, and that... 

Safety inspections, observations, and walk-throughs are a core feature of the safety management program elements. Unfortunately, these walk-through tours can evolve or be perceived as a negative, fault-finding activity that becomes adversarial between the leadership team and employees. 

The concept of human error became part of safety lore when Heinrich noted that as improved equipment and methods were introduced, accidents from purely mechanical or physical causes decreased and (hu)man failure became the predominant cause of injury. This assumption became the second of the five dominoes in the famous Domino model, described as fault of person. This is in good agreement with the philosophical and psychological tradition to treat human error as an individual characteristic or a personality trait. A modern example of that is the zero-risk hypothesis of driving, which proposes that drivers aim to keep their subjectively perceived risk at zero level. 

The geological conditions in and around a site have a major influence on the risk of gas migration. A commonly used value of 250 m is often incorrectly perceived as being the limit to which gas migration can occur. Migration has been observed to occur for distances up to 400 m along open features (e.g. open faults or other similar features). Conversely there have been sites where no migration has been observed as close as 10 m to sources that are surrounded by impermeable clay (e.g. London clay). 

The contribution from the computer system group is represented in the Laprie s dependability tree. The authors developed the concept of fault-tolerant computing, based on the idea of dependable service delivering (Avizienis et al. 2004). In this work the dependability of a system is understood as the ability to deliver service that can justifiably be trusted. The service delivered by a system is its behaviour as it is perceived by its user(s) a user is another system (physical, human) that interacts with the former at the service interface. The function of a system is what the system is intended for, and is described by the system specification. Dependability is an integrative concept that consists of three parts the attributes of, the means by, and the threats to which dependability is attained. Dependability attributes ... 

NOTE 3 If the above estimations are considered too conservative, then a detailed analysis of the failure modes of the hardware element can classify each failure mode into one of the fault classes (single-point faults, residual faults, latent, detected or perceived multiple-point faults or safe faults) wifli respect to the specified safety goal and determine the failure rates apportioned to the failure modes. Annex B describes a flow diagram that can be used to make the fault classification. 

Listeners also respond positively to questions that seek solutions and focus on the desired outcome or behavior. Such questions are more likely to be perceived as helpful while questions that are focused on the problem are perceived as seeking to find fault or place blame. Positive questions often quickly shift the focus from what has been done in the past to the future, such as current plans or what needs to be done. An effective question in continuing the discussion following the response to the question in the previous paragraph might be What are you planning to do next ... 

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