Pattern errors

If we are happy with a threshold of Punstabio = 0.01, this means that if we want to store a paltry 15 patterns, errors are likely to start appearing unless we... 

An apparent systematic error may be due to an erroneous value of one or both of the pure-component vapor pressures as discussed by several authors (Van Ness et al., 1973 Fabries and Renon, 1975 Abbott and Van Ness, 1977). In some cases, highly inaccurate estimates of binary parameters may occur. Fabries and Renon recommend that when no pure-component vapor-pressure data are given, or if the given values appear to be of doubtful validity, then the unknown vapor pressure should be included as one of the adjustable parameters. If, after making these corrections, the residuals again display a nonrandom pattern, then it is likely that there is systematic error present in the measurements. ... 

A second example is also informative. When samples are obtained from a normally distributed population, their values must be random. If results for several samples show a regular pattern or trend, then the samples cannot be normally distributed. This may reflect the fact that the underlying population is not normally distributed, or it may indicate the presence of a time-dependent determinate error. For example, if we randomly select 20 pennies and find that the mass of each penny exceeds that of the preceding penny, we might suspect that the balance on which the pennies are being weighed is drifting out of calibration. 

This determines the switching pattern of the inverter unit, based on the T and

error signals, obtained from the torque and flux comparators. Since these signals arc obtained at very high speed, the inverter IGBTs are also switched with an equally high speed to provide a quick response and an accurate T and N. 

These eiTors occur, not in spite of the fact that someone is well-trained but because he or she is well-trained. Routine operations are relegated to the lower levels of the brain and are not continuously monitored by tbe conscious mind. We would never get through the day if everything we did required our full attention. When the normal pattern or program of actions is interrupted for any reason, errors are likely to occur. These slips are very similar to those we make in everyday life. Reason and Mycielska [1] have described the psychology of such slips. 

The lighter arrows represent typical shortcuts, which omit particular stages in the information-processing chain. These shortcuts may be "legitimate," and would only lead to errors in certain cases. For example, the worker may erroneously believe that he or she recognizes a pattern of indicators and may immediately execute a skill-based response, instead of moving to the rule-based level to apply an explicit diagnostic rule. 

The practical implications of this experiment are that when evaluating the effects of shift work due to circadian effects, the type of task being carried out by the worker must be taken into account. For example, skill-based tasks would be expected to exhibit the performance changes characteristic of low memory load tasks, whereas performance variations in knowledge-based tasks would be expected to follow the pattern of high memory load tasks. Performance on rule-based tasks may depend on the degree of frequency of use of the rules, which in turn may determine the memory load. If these results were confirmed by further process plant studies, it would have implications for when different types of operation (involving different levels of memory load) should be scheduled to reduce circadian rhythm effects and minimize errors. 

This factor refers to the spatial organization of the information displays. In general, instruments displaying process parameters that are functionally related should also be physically close. In this way, it is likely that a given fault will lead to a symptom pattern that is easier to interpret than a random distribution of information. Although violation of this principle may not induce errors in a direct manner, it may hinder human performance. The following example illustrates this point. 

DECISION/ACTION ELEMENT OBJECTIVE TYPICAL ERROR PATTERNS... 

Ironically, many errors occur because a person is well trained. Routine operations are controlled by lower levels of the brain and are not continuously monitored by the conscious mind. When tlie normal pattern of action is interrupted, an error is more likely to occur. 

The general principle behind most commonly used back-propagation learning methods is the delta rule, by which an objective function involving squares of the output errors from the network is minimized. The delta rule requires that the sigmoidal function used at each neuron be continuously differentiable. This methods identifies an error associated with each neuron for each iteration involving a cause-effect pattern. Therefore, the error for each neuron in the output layer can be represented as ... 

This is also a trial and error solution following the pattern of (A), except capacities are assumed and the pressure drops are calculated to find a match for the given conditions of inlet pressure, calculating back from the outlet pressure. 

The reaction is in methanol, like iododestannylation, first-order in each reagent. The second-order rate coefficient at 23 °C was reported as 20,900 and thus the reaction occurs very much more readily than cleavage of the corresponding tin compound, which repeats the pattern observed in acid-cleavage reactions (see p. 342). The magnitude of the rate coefficient may be subject to the same error that appears to be present in the measurement of the corresponding tin compound (see footnote to Table 264) since the rates were determined under the same conditions. 

Initial comparison of CFSTR runs with similar feed conditions indicates conditions for which the monomer conversion may be dependent on mixing speed. However, when the effects of experimental error in monomer conversion and differences in reaction temperature are considered, the monomer conversion is seen to be relatively independent of mixing speed for rpm equal to or greater than 500. Comparing Run 14 with Run 12 reveals a small decrease in monomer conversion in spite of a rise in reactor temperature of 2°C. This indicated the presence of a small amount of bypassing or dead volume at the lower mixing speed. This imperfect mixing pattern would also be present in Run 15. 

---