Case-based information

As well as purely factual data and production rules, the knowledge base may contain a section devoted to case-based information. This is a library of specific examples that in the past have proved informative and that relate to the area in which the system has expertise. 

These Mo catalysts with a C2-tether connecting the phosphine and cyclopenta-dienyl ligand provide an example of the use of mechanistic principles in the rational design of improved catalysts, in this case based on information about a decomposition pathway for the prior generation of catalysts. The new catalysts offer improved lifetimes, higher thermal stability, and low catalyst loading. The successful use of a triflate counterion and solvent-free conditions for the hydrogenation are additional features that move these catalysts closer to practical utility. 

The chemical and most process factors affecting the index are quite straightforward to estimate. More problematic are the equipment safety and the safety of process structure. The equipment safety subindex was developed based on evaluation of accident statistics and layout information. The evaluation of the safe process structure subindex is based on case-based reasoning, which requires experience based information on accident cases and on the operation characteristics of different process configurations. 

In design it is typical that the same mistakes are done again since the use of available information is not organized. The use of case-based reasoning enhances the reuse of available experience, which reduces the possibility that the same errors are done more than once. In this work CBR was used for the evaluation of the inherent safety of process structure. The casebase was collected from design standards, accident documents and good engineering practice. 

Hurme, M. Heikkila, A-M. 1998. Synthesis of Inherently Safe Chemical Processes by Using Genetic Optimization and Case-Based Reasoning. In Koikkalainen, P. Puuronen, S. (Eds.). Human and Artificial Information Processing. Finnish Artificial Intelligence Society. Espoo. Pp. 134—143. 

Along with carbon, hydrogen and oxygen, lignocellulosic biomass also contains hetero elements such as alkali and other metals. The amounts of these ashes vary over a broad range, from 30-50 wt.% in chicken litter to 1-3 wt.% in wood. Moisture is always present in lignocellulosic biomass and can be up to 80 wt.% in some cases. Detailed information on the composition of biomasses can be found in data bases, e.g., Phyllis [21] from the Dutch Energy Research Foundation (ECN). Table 6.2 lists the compositions of some typical biomasses. 

Critical measurement failure. In this case, the information presented to the operator is incorrect. An expert system would use a process knowledge base to detect inconsistencies and to alert the operator. 

The methods developed from either NN or IT undoubtedly reduce the requirements concerning the hardware that must be applied. In the NN approach it is sufficient to determine electrostatic potential, for which far less computer resources are required than for solving HFR equations supplemented with the energy of correlations, necessary for reliable calculation of interaction energy. Similarly, the calculation of information entropy (the IT case) based on the electron density is possible, and can be done with much shorter calculation time than in the case of HFR equations with the correlation energy. 

There is an enormous variability in the extent and nature of different databases for chemical substances. Eor example, in some cases, the evaluation of a chemical must be based on hmited data in experimental animals, whereas in other cases detailed information on the various endpoints, toxicokinetics, and mode(s) of action may be available. In some cases, the evaluation can be based on data on effects in exposed human populations. Clearly as the amount of information available increases, the degree of understanding of the hazards expressed also increases, and the uncertainties due to lack of information decrease. However, even with complex databases, rmcer-tainties still remain. 

The maximum entropy method (MEM) is an information-theory-based technique that was first developed in the field of radioastronomy to enhance the information obtained from noisy data (Gull and Daniell 1978). The theory is based on the same equations that are the foundation of statistical thermodynamics. Both the statistical entropy and the information entropy deal with the most probable distribution. In the case of statistical thermodynamics, this is the distribution of the particles over position and momentum space ( phase space ), while in the case of information theory, the distribution of numerical quantities over the ensemble of pixels is considered. 

Ranky, P. G. (2003), A 3D Web-enabled, case based learning architecture and knowledge documentation method for engineering, information technology, management, and medical science/biomedical engineering, Int. J. CIM, 16(4-5). 346-356. 

The validation and qualification procedures presented in this chapter help to assure compliance and quality at minimal extra cost and minimal administrative complexity. The purpose is to answer the key questions regarding validation How much validation is needed, and how much is sufficient The recommendations are complementary rather than controversial to any standards or official guidelines. They are based mainly on common sense and can be used in cases where information from official guidelines and standards is insufficient for day-to-day work. We list the major steps of each qualification, but for an in-depth understanding and for easy implementation, readers are directed to the literature [2,7,8,13]. 

The application of ESCA to the elaboration of chemical composition is well established in the case of fluorocarbon based systems for which the span in shift range for the Cu level is particularly favourable consequent upon the large electronic effect of replacing hydrogen by fluorine. In many cases comparable information may be derived from the more familiar spectroscopic techniques such as 1R and NMR one area in which ESCA comes into its own, however, is in the analysis of polymeric... 

In some cases new information may be revealed as a result of charring. The infrared spectrum of charred common milkweed (Figure 10) displays oxalates that are not as apparent in the uncharred sample. In some cases of charred fibers, the spectrum can be said to be cellulosic, but further distinction of the organic structure based on lignins cannot be made. 

Because they are isoelectronic, it is reasonable to expect that imine radical anions (>C=N— ) would exhibit chemistry analogous to that of >C=0. Such does appear to be the case, based upon the limited information available. 

Until now, the variable in every system has been discrete for example, the number obtained when a die is cast. As not only a discrete variable but also a continuous variable (for example, time) appears very often in chemical engineering, it is necessary to define the information entropy for continuous variable. Of course, it is possible to define the average amount of information for a system that is based on a continuous variable, for example, time. In the case based on a continuous variable t, let p tt) and At be the probability density at t and the very small change of continuous variable, respectively. The product of pif) and At corresponds to the probability P , in Eq. (1.3). When this method of... 

FIGURE 6-5 Gasoline use cases based on the committee s optimistic vision compared with Energy Information Administration (EIA) projections of oil supply, demand, and imports, 2000-2050. SOURCE EIA (2003) for EIA projections. 

Few randomized controlled studies have been performed for antifungal drugs because of the difficulty in recruiting a sufficient number of cases within a given time frame. Evidence-based information is scant, as many of the reports have been in the form of single case reports, studies of small numbers of patients, or retrospective reviews of patient records (Table 11-13). 

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