Minimizing Errors

Accuracies of the flow meters discussed herein are specified as either a percentage of the full-scale flow or as a percentage of the actual flow rate. It may be convenient in some appHcations to compare the potential inaccuracies in actual volumetric flow rates. For example, in reading two Hters per minute (LPM) on a flow meter rated for five LPM, the maximum error for a 1% of full-scale accuracy specification would be 0.01 x 5 = 0.05 LPM. If another flow meter of similar range, but having 1% of actual flow rate specification, were used, the maximum error would be 0.01 x 2 = 0.02 LPM. To minimize errors, meters having full-scale accuracy specifications are normally not used at the lower end of their range. Whenever possible, performance parameters should be assessed for the expected installation conditions, not the reference conditions that are the basis of nominal product performance specifications. 

The practical needs of military and aerospace systems tended to focus interest on human-machine interfaces (e.g., aircraft cockpits), with particular emphasis on information displays and the design of controls to minimize error. The predominant model of the human prevalent at that time (called behaviorism) concentrated exclusively on the inputs and outputs to an individual and ignored any consideration of thinking processes, volition, and other... 

It is important, however, not to take this analogy too far. In general, the performance of a piece of hardware, such as a valve, will be much more predictable as a function of its operating conditions than will human performance as a function of the PIFs in a situation. This is partly because human performance is dependent on a considerably larger number of parameters than hardware, and only a subset of these will be accessible to an analyst. In some ways the job of the human reliability specialist can be seen as identifying which PIFs are the major determinants of human reliability in the situation of interest, and which can be manipulated in the most cost-effective manner to minimize error. 

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. 

Three main opportunities for applying the techniques to minimize error and maximize performance can be identified ... 

Here,5 is a correlation equation which minimizes errors of p2 (PsiO P f(y)=y/, where n is between -0.2 and 1. 

Fig. 7 Dependence of IR band intensities on H2 partial pressure during ethene hydrogenation catalyzed by Ir4/y-Al203 at 288 K and 760 Torr (40 Torr C2H4, 50-300 Torr H2, and the balance He). The bands at 2990 (diamonds) and 2981 cnr (squares) were chosen to represent di-cr-bonded ethene and that at 1635 cnr (circles) to represent water on the y-AbOs support. These IR bands were chosen as the best ones to minimize error caused by overlap with other bands. The triangles represent the reaction rate expressed as a turnover frequency (TOF), the rate of reaction in units of molecules of ethene converted per Ir atom per second. The data indicate a correlation of the band intensities with the TOF, consistent with the suggestion that the ligands represented by the bands are reaction intermediates (but the data are not sufficient to identify the reaction intermediates) [39]...

C. Practical Implementation. As a cross-ffactionation method GPC has one very definite advantage over other methods-it can clearly show the number of variables affecting the results. Thus, despite the complexity of the problem, guidelines which minimize error and begin to provide useful results have been developed. They are summarized as follows ... 

These drawbacks of the Rosholt isochron largely disappear when used for igneous systems, where Th, being the most-abundant actinide, is measured with approximately equal or better precision than the other U-Th isotopes, thus minimizing error correlations. In fact, for data where all analyses have relatively high Osmond diagrams can... 

On NP tests of gross motor activity and fine motor speed, he was mildly impaired in comparison to adult norms. However, he was able to attain normal performance levels with practice and direct encouragement. It is important to note that all other NP tests of sensory, perceptual, and conceptual functions were in the normal range his minimal errors are often made by normal, nonimpaired 1 ndi vidua1s. 

Alternatively, the definition of the mean transition time (5.4) may be obtained on the basis of consideration of optimal estimates [54]. Let us define the transition time i) as the interval between moments of initial state of the system and abrupt change of the function, approximating the evolution of its probability Q(t.X(t) with minimal error. As an approximation consider the following function v /(f,xo, ) = flo(xo) + a (xo)[l(f) — l(f — i (xo))]. In the following we will drop an argument of ao, a, and the relaxation time d, assuming their dependence on coordinates of the considered interval c and d and on initial coordinate x0. Optimal values of parameters of such approximating function satisfy the condition of minimum of functional ... 

PN regimens for adults can be based on formulas (Fig. 60-2), computer programs, or standardized order forms. Order forms are popular because they help educate practitioners and foster cost-efficient nutrition support by minimizing errors in ordering, compounding, and administering. 

Either calibration graphs prepared from standards or the method of standard addition (p. 30) can be used. For the former, the standards should be as similar as possible in overall chemical composition to that of the samples so as to minimize errors caused by the reduction of other species or by variation in diffusion rates. Often, the limiting factor for quantitative work is the level of impurities present in the reagents used. 

A variety of online solid extraction devices and applications have been developed for bioanalysis. Many are easy to build in laboratories or commercially available. Unlike offline methods, minimal operator intervention is needed for daily sample analysis after online applications are set up, so the approach is both labor- and cost-effective. The technique can also minimize errors arising from manual operations, eliminate potential inconsistencies caused by different operators, and provide accessibility of LC/MS/MS applications to laboratories that have minimal analytical expertise. 

Noncompartmental analysis is limited in that it is not descriptive or predictive concentrations must be interpolated from data. The appeal of noncompartmental analysis is that the shape of the blood concentration-versus-time curve is not assumed to be represented by an exponential function and, therefore, estimates of metabolic and pharmacokinetic parameters are not biased by this assumption. In order to minimize errors in parameter estimates that are introduced by interpolation, a large number of data points that adequately define the concentration-versus-tie curve are needed. 

This is a very robust estimator which does not assume normality, linearity, or minimal error of measurement. 

Most of the interaction parameters employed were taken from other studies (20, 21), and are reportedly obtained by minimizing errors in the match of phase equilibrium data. However, in (21), the SRK equation employed was slightly different from that used here. The parameters for CO2 - H2O were chosen because they had been shown to give a critical line which is qualitatively correct. The H2O - CO interaction parameter is the value given in (20) for H2S - CO. For H2O - H2, kij was taken to be -0.25 in the absence of any literature studies. 

Burke and Schumann [9] suggested that the effects of Assumptions 2 and 3 compensate for each other, thereby minimizing errors. Although D increases as T167 and velocity increases as T, this disparity should not be the main objection. The main objection should be the variation of D with T in the horizontal direction due to heat conduction from the flame. 

The Council encourages collaboration among industry, regulators, standards-setters, health care professionals, and patients to facilitate design of packaging and labeling to help minimize errors. 

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