Error precursors

In these expressions Wn always refers to the individual / in the corresponding error class under consideration, while the fs in the sums refer to the corresponding precursors of Ii, for example, into all d one-error precursors or in 1, (to all d of the (d — 1 )-error precursors of /(. Note that due to the iterative nature, the first sum term in contains d d-fold products of terms. 

The first study found 40 active failures (i.e., direct error precursors) and nine latent failures (i.e., dormant states predisposing the system to later errors). Four broad classes of active failures were ... 

Error precursor analysis identifies the specific error precursors that were in existence at the time of or prior to the accident. Error precursors are unfavorable factors or conditions embedded in the job environment that increase the chances of error during the performance of a specific task by a particular individual or group of individuals. Error precursors create an error-likely situation that typically exists when the demands of the task exceed the capabilities of the individual or when work conditions aggravate the limitations of human nature. 

Review initial error precursor list in a workshop with the same mine staff used in 8 above. 

Potential error precursors, (existing conditions that increase error rates) should be assessed as to their impact on safe job completion. For example, time pressure to complete a job can result in the employee expected to take short cuts or accept risk as part of the job. Error precursors are unfavorable prior conditions...that increase the probability for error during a specific action (US DOE, 2009a). Refer to Table 2.1 for a comparison on human error precursors concerning task demands and individual capabilities and... 

Table 2.1 Human error precursors - task demands and individual capabilities Task demands Individual capabilities...

Table 2.2 Additional human error precursors - work environment and human nature Work environment Human nature...

Table 2.2 for additional human error precursors concerning work environment and human nature. 

The HPI principles along with an understanding of human error precursors can be used to enhance the development of the JHA process. If a fundamental attribute of humans is that they can make mistakes and make wrong decisions then it becomes important to ensure that job requirements... 

Potential error precursors should be assessed as to their impact on safe job completion. As an example, time pressure to complete a job can result in the employee expected to take short cuts or accept risk as part of the job. 

The use of a model of human error allows a systematic approach to be adopted to the prediction of human failures in CPI operations. Although there are difficulties associated with predicting the precise forms of mistakes, as opposed to slips, the cognitive approach provides a framework which can be used as part of a comprehensive qualitative assessment of failure modes. This can be used during design to eliminate potential error inducing conditions. It also has applications in the context of CPQRA methods, where a comprehensive qualitative analysis is an essential precursor of quantification. The links between these approaches and CPQRA will be discussed in Chapter 5. 

Alcohol dehydrogenase, 178 Alkaline error, 149 Alkaline phosphatase, 185 Alkanethiols, 46, 123 Alkoxide precursor, 120 Amino acids, 92, 187 Ammonium sensor, 181, 182 Amperometric sensors, 172 Aniline, 35, 39... 

A hypercycle is a more complex organisation form. Its precondition is the presence of several RNA quasi-species which are able to amalgamate chemically with certain proteins (enzymes or their precursors). If such a protein is linked to a quasi-species, the resulting duo favours the replication of a second quasispecies. According to Dyson, the linked populations get stuck in a stable equilibrium. Problems occur at this level Any theory on the origin of replication has the central problem that the replication process must occur perfectly in order to ensure survival . If there are replication errors, these will increase from generation to generation, until the system collapses the error catastrophe has then occurred ... 

A departure from traditional approaches of depositing a significant amount of metal onto carbon precursor differentiated our experiments from the state of the art literature. Through several trial and error experiments, it was possible to formulate several key principles, which should constitute a design of the metal/carbon composites. Among those are ... 

The answer to the question is that in the vast majority of all accidents, re-occurring deviations, which were defined as precursors, are present. That a variety of events were present prior to accidents, was stated by Heinrich (Heinrich, 1931). He combined the common cause model and the descriptive iceberg model, stating that prior to an accident, increased numbers of near misses, errors and recoveries are present. Subsequently, Turner (Turner, 1978) identified a so-called incubation period prior to accidents, in which all sorts of events occur unnoticed or are misinterpreted. However, neither study indicates types, or categories of events that can act as precursors of accidents. 

The copyrolysis of 1 wt% dibromotetrafluoro-p-xylylene with commercially available hexafluoro-p-xylene (Aldrich) with metals was examined and it was found that it was indeed possible to prepare films that were spectroscopically indistinguishable from those deposited from dimer. The PA-F films obtained are of excellent quality, having dielectric constants of2.2-2.3 at 1 MHz and dissociation temperatures up to 530°C in N2. A uniformity of better than 10% can be routinely achieved with a 0.5-gm-thick film on a 5-in. silicon wafer with no measurable impurities as determined by XPS. During a typical deposition, the precursor was maintained at 50°C, the reaction zone (a ceramic tube packed with Cu or Ni) was kept at 375-550°C, and the substrate was cooled to -10 to -20°C. The deposited film had an atomic composition, C F 0 = 66 33 1 3 as determined by XPS. Except for 0, no impurities were detected. Within instrumental error, the film is stoichiometric. Poly(tetrafluoro-p-xylylene) has a theoretical composition ofC F = 2 1. Figure 18.2 illustrates the XPS ofthe binding energy... 

What are the main error sources in PAC experiments One of them may result from the calibration procedure. As happens with any comparative technique, the conditions of the calibration and experiment must be exactly the same or, more realistically, as similar as possible. As mentioned before, the calibration constant depends on the design of the calorimeter (its geometry and the operational parameters of its instruments) and on the thermoelastic properties of the solution, as shown by equation 13.5. The design of the calorimeter will normally remain constant between experiments. Regarding the adiabatic expansion coefficient (/), in most cases the solutions used are very dilute, so the thermoelastic properties of the solution will barely be affected by the small amount of solute present in both the calibration and experiment. The relevant thermoelastic properties will thus be those of the solvent. There are, however, a number of important applications where higher concentrations of one or more solutes have to be used. This happens, for instance, in studies of substituted phenol compounds, where one solute is a photoreactive radical precursor and the other is the phenolic substrate [297]. To meet the time constraint imposed by the transducer, the phenolic... 

AAdien a sequence of errors and failures propagate to the incident level, enough precursor occurrences have occurred to indicate that the current chain of occurrences represents a systemic problem. Systemic problems should not be blamed on an individual. Instead, management must find the system weaknesses and fix them before the next individual... 

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