Requirements errors

If is available as a function of temperature, Eq. (2-174) can be solved directly for the flash point temperature. Otherwise, trial and error with a table of vs. T is required) Errors average about 5°C but may be as much as 15°C. 

Proper fixation is one of the most critical steps in an in situ RT-PCR or in situ hybridization experiment, because each tissue type must have optimized fixation conditions. Particularly archival tissues may require individual specific treatment in order to meet with in situ experimental requirements. Errors in fixation will only be discovered after the entire hybridization process has been completed (see Note 10). 

To construct the adsorption isotherm, the adsorption, desorption, and calibration cycle shown in Fig. 15.11 is repeated for each data point required. Errors are not cumulative since each point is independently determined. Relative pressures corresponding to each data point are established by measuring the saturated vapor pressure using any of the preceding methods or by adding 15 torrs to ambient pressure. Thus, if X is the mole fraction of adsorbate in the flow stream, the relative pressure is given by... 

Assuming approximately equal error in the five variables, a 1% maximum error in Z requires errors in the variables of <0.2%. 

For Z 0.9 and for approximately equal error in the five variables, a 1% maximum error in B requires errors in the variables of less than about 0.02%. This is because the divisor Z — 1 0.1. In the limit as Z -> 1, the error in B approaches infinity. 

Here, neural network techniques are used to model these process-model mismatches. The neural network is fed with various input data to predict the process-model mismatch (for each state variable) at the present discrete time. The general input-output map for the neural network training can be seen in Figure 12.2. The data are fed in a moving window scheme. In this scheme, all the data are moved forward at one discrete-time interval until all of them are fed into the network. The whole batch of data is fed into the network repeatedly until the required error criterion is achieved. 

This value rests on the experimental and thermodynamic data for the absolute rate of recombination of CH3 radicals, thermodynamic data for C2H6, CH4, etc., the bond energy in methane (CH3—H), and an assumed value for the entropy of CJIT3. It is very doubtful if all of these collectively could be sufficiently in error at 900°K to cause an error in k of as much as a factor of 10 to 20. (Note that this would require errors in A// of 4 to 6 Kcal and errors in AaS of 4 to 5 cal/mole-°K.) And observe that the chain varies only as... 

VBA allows you to equate a variable to an object, but the variable does not automatically become an object. If you then attempt to use the variable in an expression that requires an object, youll get an "Object required" error message. The Set command lets you define a variable or property as an object. The following example makes the InputBox method return an Object (so that you can use its Address property in addition to its Value property, for example) ... 

Laser ablation can be carried out on any material without special sample preparation. The laser beam can be directed onto a defined spot of the sample or moved to different parts to analyse over a defined area. It can be moved in an XYZ plane using a stepper motor and driven in translational motions on which the cell is mounted and with more expensive models can be turned for analysis in other parts of the sample. Lasers can operate in UV, visible, and IR regions of the spectrum and a recent development in laser technology uses neodymium yttrium aluminium garnet (Nd YAG) which gives high repetition rate at a comparatively low power. This method of analysis is suited to bulk analysis of solid materials and the amount of volatility varies from sample to sample. The size of the laser spot can vary from 10 to 250 pm and little or no sample preparation is required. Errors are greatly reduced because of the simple sample preparation, and the fact that no solvents are required reduces interferences. 

If we consider the structural data in the light of the fact that the input to these calculations is simply the atom types and lattice structure, this data establishes the QM approach as a predictive tool for studying the structure of silicates. On the whole, observed bond lengths are reproduced to better than 1 % and elastic properties within 10%. The variation in results published by different authors is rather large and, for the PW-LDA calculations, is apparently due mainly to the different choices of pseudopotential. A meaningful comparison of different approximations to DFT or of those with the HF approximation requires errors in the energy expression to be confined to a few meV per formula unit. 

The mental models of the system developers are also important. During software development, for example, the programmers models of required behavior may not match the engineers models (commonly referred to as a software requirements error), or the software may be executed on computer hardware or may control physical systems during operations that differ from what was assumed by the programmer and used during testing. The situation becomes more even complicated when there are multiple controllers (both human and automated) because each of their process models must also be kept consistent. 

The final level. Operations, provides a view of the operational system and acts as the interface between development and operations. It assists in designing and performing system safety activities during system operations. It may contain required or suggested operational audit procedures, user manuals, training materials, maintenance requirements, error reports and change requests, historical usage information, and so on. 

Lutz, Robyn R. Analyzing software requirements errors in safety-critical, embedded systems Proceedings of the International Conference on Software Requirements, IEEE, January 1992. 

Functional Independence, which minimises the likelihood of common requirements error (including their interpretation) [SAE ARP4754A, paragraph 5.2.3.2.1.1]. Functional Independence is substantiated when the common source of error between multiples requirement sets have been minimised at the appropriate FDAL at all levels of requirements decomposition. 

It is usual, in practice, to ignore the Rabinowitsch equation and to assume that the velocity profile for the polymer liquid is parabolic to within the required error. With this assumption the wall shear rate is taken to be given by the Newtonian value, so that, from eqns 7.13 and 7.17, the apparent viscosity is... 

DIO Condition testing Expression Requirements Errors in (McDonald et... 

Simultaneous running of appropriate reference standard is required Errors originating from the incomplete distribution of spraying Variation of layer stmeture along the plate... 

In multiple-version dissimilar software, a set of two or more computer programs are developed separately (and independently) to satisfy the same functional requirements. Errors specific to one of the versions should be detected by comparison of the outputs between the different versions. When multiple-version dissimilar software is used in redundant computer systems, the likelihood of the same errors in both systems is theoretically significantly reduced, thereby achieving a higher level of safety for the system. Multiple-version dissimilar software involves applying the dissimilar design concept to software. 

A good second line check on design. Covers the effects of design errors (e.g. SA/V error, requirements error), manufacturing errors (e.g. production process error), maintenance errors, operational errors (e.g. operator failure), the effects of common component failures (e.g. common S/W in redundant systems), cascading faults, common external source faults, etc. 

In order to determine the length L of the sequence of random numbers which assures calculation of MCD figures with a required error e, one may adopt a heuristic method - for example an expensive self-consistent type method, or a function... 

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