Interpretation of result

A major criticism of neural networks is that it is difficult to interpret the meaning of the weights, after training. A network s performance may be acceptable but lend no insight into how it works, a problem reminiscent of principal component analysis component functions are often hard to interpret. This is a difficult and important challenge for future research. 

Z i(E) can be considered as a product of an ionic excitation density of states and an energy-dependent coupling constant. In model calculations one can independently vary the shape and the band with of the denstiy of states and the strength of the coupling constant. In the present case we can only vary these parameters indirectly by changing the atomic number Z. Since the self-energy involves the polarizability of the ionic system there must be an oscillator-strength sum rule such that 

In the transition from a broadband to a narrow band situation, there is a critical case when the positive slope part of Re Z4p(E) becomes parallel to E-E4p (in a point or over a region). On the broad-band side (low Z), we have for all E 

It the unperturbed discrete level is placed inside the region of anomalous dispersion where 

We now have the necessary background for understanding the behaviour of the XPS spectra in Figs. 24 and 28 through the characteristics of the calculated self-energies in Figs. 25 and 29. 

It should be noted that as long as one only considers the quasi-stationary split-off level, the problem can be treated using multi-configuration Hartree-Fock techniques. In this way, Aoyagi et al.89) have calculated a very accurate position for the 4p 2P3/2 level in Xe. 

The interpretation of uncertainty analysis results can cover a wide range of issues. Here, we consider the interpretation of results with regard to the needs of decision-makers who would use the results of uncertainty analysis in exposure assessment. The discussion is primarily based upon Morgan Henrion (1990), Bloom et al. (1993) and Thompson Graham (1996). The discussion is organized on the basis of key questions that decision-makers often ask, as reported by Bloom et al. (1993), based upon a survey of senior risk managers at the USEPA, and as described by Thompson Graham (1996)  

Knowledge of key sources of uncertainty in exposure estimates helps guide additional data collection to reduce uncertainty in order to improve the precision of the estimates. For example, the identification of key sources of uncertainty can be used to prioritize information-gathering efforts for the most important inputs. Because uncertainty results from lack of knowledge, an effective approach to its reduction is to obtain more knowledge, through additional measurements or the development of more precise and accurate measurement methods. 

The preceding identification and discussion of key questions posed by decision-makers highlight the importance of identifying and characterizing uncertainty. The broad range of questions illustrates the importance of knowing what questions must be answered before 

The preceding chapter demonstrates how the basic thermal, compositional, and cloud structures of planetary atmospheres can be inferred from infrared measurements. Some information on surface properties is also available. So far, however, there has been no discussion of how underlying physical processes cause these structures to develop and evolve. That is the purpose of this chapter. 

We divide the discussion into four topics. In Section 9.1 we are concerned with the one-dimensional thermal equilibrium configuration of an atmosphere in the absence of internal motion. In Section 9.2 we expand the temperature field to three dimensions and investigate the dynamical properties of atmospheres. In Section 9.3 we address the question of how determinations of chemical composition imply the evolution of planets and the Solar System as a whole. Finally, in Section 9.4 we review measurements of the excess heat emitted by the planets, and discuss the importance of these measurements for determining the status of planetary evolution in the present epoch. 

The routine samples taken from a water supply should be reviewed regularly and at least once a year. This will give a profile of microbiological quality over a 

Excellent. No coliforms or E. coli detected in any 100 ml sample. Satisfactory. One to three coliforms per 100 ml of sample. No E. coli should be present. Coliforms should not be present in consecutive samples and not present in more than 5% of samples. 

The graphical presentation allows at least a subjective assessment to be made of the significance of the recorded changes. In some cases, a clear trend is apparent with little masking by scatter of results, in others the scatter appears dominant. Obviously, the cases with very large scatter lead to larger uncertainty in the level of change found. 

Care has to be taken in drawing conclusions on the relative performance of materials because of the large uncertainties. Also, the practical significance of the levels of change will to some extent depend on particular products and applications. 

No detailed analysis of each compound, property by property, has been attempted but comment is made on the general picture which emerges for each property. Four overall observations can be made. 

The performances in the three different climates do not always rank consistently in the same order. Hence, it is not sensible to rigidly classify the climates covered in terms of severity. 

There are considerable differences in the magnitude of the response to ageing as measured by different properties, which illustrates the generally held view that preferably several relevant properties should be investigated in any ageing trial. It is also clear that the experimental scatter varies very significantly between properties. 

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At the micro-scale level, there really is no way to measure concentration fluc tuations. Resort must be made to other qualitative interpretation of results for either a process or a chemical reac tion studv. 

Understanding the positions of sample and other measurement locations within the equipment is also important. The presence or absence of isolation valves needs to be identified. While isolation valves may be too large for effective sampling, their absence will require that pipe fitters add them such that sample valves can be connected. This must be done in advance of any test. If analysts assume that samples are from a liquid stream when they are vapor or that temperature measurements are within a bed instead of outside it, interpretation of results could be corrupted. Analysts should also develop an understanding of control transmitters and stations. The connection between these two may be difficult to identify at this level in fully computer-controlled units. 

Each test has specific limitations and may pass defects of various sizes and orientations. The specific limitations for a particular technique must be understood for correct interpretation of results. For example, hydrostatic tests and air-underwater tests may pass defects that run 70% of the wall thickness. Hydrostatic tests may pressurize a defect in such a way that leaking does not occur in the test but can in service. 

Biological monitoring of cadmium workers is also recommended guidance on interpretation of results is given in EHl - Cadmium health and safety precautions.)... 

Most recent publications by Hartshorn and his collaborators introduce a note of caution with regard to the mechanistic interpretation of results obtained in BF3-catalyzed epoxide cleavage reactions. They point out the marked dependence of the course of the reaction on the solvent used, either... 

Carbon monoxide is usually sampled as the second parameter in conjunction with carbon dioxide or oxygen. In theory, as the optimum is usually to have near-stoichiometric combustion without CO breakthrough it is the most reliable gas to sample. A problem is that although small quantities of CO usually indicate the need for additional air, they can also be caused by flame chilling and careful interpretation of results is needed. 

The NACE publication Corrosion Fatigue gives a comprehensive account of all aspects of the subject, and in this work a review of the application of fracture mechanics for studying the phenomenon has been presented by McEvily and Wei , whilst Kitagawa has given a detailed account of crack propagation in unnotched steel specimens. This work should be consulted for details of testing and interpretation of results. 

The measurement of filth elements by microanalysis is a valuable adjunct in the enforcement of the Food, Drug, and Cosmetic Act and serves as an efficient means of evaluating conditions of cleanliness, decency, and sanitation in food-producing plants. This, of course, is in addition to the value of microanalytical methods in the determination of the fitness of foods as they reach the consumer. The techniques available, together with proficiency of manipulation, repeated references to authentic materials, and sound judgment in the interpretation of results, provide effective enforcement weapons in the constant war to prevent the production and interstate distribution of products which are unfit for the table of the American consumer. 

The pursuit of operations research consists of (a) the judgment phase (what are the problems ), (b) the research phase (how to solve these problems), and (c) the decision phase (how to act on the finding and eliminate the problems). These phases require the evaluation of objectives, analysis of an operation and the collection of evidence and resources to be committed to the study, the (mathematical) formulation of problems, the construction of theoretical models and selection of measures of effectiveness to test the models in practice, the making and testing of hypotheses as to how well a model represents the problem, prediction, refinement of the model, and the interpretation of results (usually as possible alternatives) with their respective values (payoff). The decision-maker generally combines the findings of the... 

Thus, if a field representative believes that the task is completed when the testing of water samples is performed and a service report is issued, or if the representative s interpretation of results is poor, problems will undoubtedly develop. Also, if he or she fails to adequately review the bigger picture rather than merely individual results, the problems will magnify and the contract will ultimately be lost. 

As pointed out above, accumulatory pressure and weight loss measurements usually refer to the total reaction. When there are several volatile products, it is necessary to identify all components and investigate progressive changes in gas composition. Quantitative determinations of the amounts of each product (EGA) should, ideally, be combined with measurements of the total extent of reaction, although Gam [143] has recommended caution in the interpretation of results from simultaneous measurements. 

The variations of dielectric constant and of the tangent of the dielectric-loss angle with time provide information on the mobility and concentration of charge carriers, the dissociation of defect clusters, the occurrence of phase transitions and the formation of solid solutions. Techniques and the interpretation of results for sodium azide are described by Ellis and Hall [372]. 

Let us note that this definition of y breaks the limits of the Kielson-Storer model and can cause a few contradictions in interpretation of results. If the measured cross-section oj appears to be greater than oo, then, according to (3.45), the sought y does not exist. To be exact, this assertion is valid relative to the cross-section of the rotational energy relaxation oe = (1 — y2)oot since y2 is always positive. As to oj, taking into account the domain of negative values of y, corresponding to the anticorrelated case (see Chapter 2), formula (3.45) fails to define y when oj > 2co. 

There are no specific requirements for the solid electrolytes (pellets or tubes) used in electrochemical promotion experiments. However they should be stable under the conditions of the experimental study. Also one should know the type of ionic conductivity and the possibility of appearance of mixed ionic-electronic conductivity under the conditions of electrochemical promotion. This is quite essential for the correct interpretation of results. Addresses of suppliers of solid electrolytes included in Table B.l are presented below ... 

Research use of analytical results in the framework of a nonanalytical setting, such as a governmental investigation into the spread of pollution here, a strict protocol might exist for the collection of samples (number, locations, time, etc.) and the interpretation of results, as provided by various consultants (biologists, regulators, lawyers, statisticians, etc.) the analytical laboratory would only play the role of a black box that transforms chemistry into numbers in the perspective of the laboratory worker, calibration, validation, quality control, and interpolation are the foremost problems. Once the reliability and plausibility of the numbers is established, the statisticians take over. 

If the graph y vs. x suggests a certain functional relation, there are often several alternative mathematical formulations that might apply, e.g., y - /x, y = a - - exp(b (x + c))), and y = a-(l- l/(x + b)) choosing one over the others on sparse data may mean faulty interpretation of results later on. An interesting example is presented in Ref. 115 (cf. Section 2,3.1). An important aspect is whether a function lends itself to linearization (see Section 2.3.1), to direct least-squares estimation of the coefficients, or whether iterative techniques need to be used. 

Many investigators have studied the in vivo degradation kinetics of lactide/glycolide materials (5,35-39). There has been some confusion in the interpretation of results primarily because of lack of consistency in nomenclature and careful attention in describing the specific stereoisomers evaluated. Nevertheless, the overall degradation kinetics are fairly well established for the entire family of homopolymers and copolymers. At the present, this common knowledge of the in vivo lifetimes of various lactide/glycolide polymers is a primary reason for their popularity. 

The rate of urine amylase excretion is a sensitive reflection of the amylase released into the blood. The urine amylase remains abnormal 1-2 weeks after the serum returns to normal because the renal clearance of amylase rises 3-fold in acute pancreatitis and takes 1-2 weeks to return to normal. In pancreatitis, a number of investigators have reported a higher percentage of urinary amylase elevations, as contrasted with serum amylase elevations, particularly when the urinary amylase output over an interval is measured. Random urine collections for one, two and 24 hours are 792-4264 (2926 1074 S.D.) units per 24 hours. However, the wide range of normals make interpretation of results difficult. Of 107 patients with elevated serum or urine amylases, 16 were found to have a normal pancreas at operation (78). 

In principle, these approaches are very attractive because they probe multiple pathways in the critical regions where the pathways are separated, but in practice these are extremely challenging experiments to conduct, and the interpretation of results is often quite difficult. Furthermore, these experiments are difficult to apply to bimolecular collisions because of the difficulty of initiating the reaction with sufficient time resolution and control over initial conditions. 

The carryover effect is only one type of issue that may complicate the interpretation of results from a cross-over study. A more complete description of the potential pitfalls in the analysis of cross-over studies is beyond the scope of this chapter. The reader should simply be aware that, although cross-over studies may be less expensive to conduct than parallel trials initially, they also carry a higher risk of producing results that are fficult or impossible to interpret, thus requiring that the study be repeated to obtain clear results. 

Interpretation of test results. The outcomes of tests are compared with norms and tolerances to determine sizes and directions of deviations. It is important to discuss how operators and QA managers who judge test results should be informed about the interpretation of results and which decision-support systems such as control charts are relevant. 

However, care must be exercised in the interpretation of results that show the presence of putative metabolites. An illustrative example is provided by a study of the biodegradation... 

It can be seen that these definitions are derived from experimental observation and are no more than classifications based on a set of properties shared by a group of substances. They are scientifically inadequate for the interpretation of results, which requires a definition based on concepts. Historically, the attempt to provide a model rather than a classification comes in the form of a search for imderlying universal principles. It seems that the alchemists recognized vague principles of acidity and alkalinity, and in the 17th century the iatrochemists made these the basis of chemical medicine. Disease was attributed to a predominance of one or other of these principles (Pattison Muir, 1883). 

The most common mechanical property of cements that has been measured routinely is compressive strength (Polakowski Kipling, 1966). Measurement is easy to carry out but there are several reasons to consider that the results from the technique are unsatisfactory. Interpretation of results is uncertain because of the complexities in the mode of failure. Minor imperfections in the material lead to localized stress concentrations which affect the magnitude of the result. 

With respect to sampling, sufficient numbers of environmental samples should be obtained to permit reliable statistical and biologic Interpretation of results. At the same time, the samples collected should be from environmental locations where human exposure Is most likely to occur (or did occur. If questions of past exposures require assessment). They should also be targeted for those environmental media which can be expected to have the greatest potential for human exposure and absorption. Finally, the samples must be obtained and preserved so that the chemicals which pose the greatest threat for human health In terms of toxicity and tissue persistence can be accurately measured. 

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