Knowledge-based rules

Natural mutation of amino acids in the core of a protein can stabilize the same fold with different complementary amino acid types, but they can also cause a different fold of that particular portion. If the sequence identity is lower than 30% it is much more difficult to identify a homologous structure. Other strategies like secondary structure predictions combined with knowledge-based rules about reciprocal exchange of residues are necessary. If there is a reliable assumption for common fold then it is possible to identify intra- and intermolecular interacting residues by search for correlated complementary mutations of residues by correlated mutation analysis, CMA (see e.g., http //www.fmp-berlin.de/SSFA). 

Figure 5. Development of knowledge base rules to select column and mobile phase constituents. indicates "direct hit".

Grapheme-to-phoneme conversion by rule is perhaps the classic application of traditional knowledge based rules in TTS. Indeed, in the past it was thought that this was how humans performed the task when presented with an unknown word they would apply a set of rules to find the pronunciation. The most common approach is to process the character sequence left-to-right, and for each character apply one or more rules in order to generate a phoneme. It should be clear that these rules can t operate in isolation, otherwise a t character would always result in a /t/ phoneme. Rather the character context of the character is used and in this was we can generate /th/ when t is followed by h. 

Because the activation of knowledge-based actions depends on the information perceived by the operator, information filtering, distortion, or biases may impact when action rules are activated. This could lead to hmnan error events such as the execution of a knowledge-based rule during an inappropriate situation (Reason, 1990). 

What mental and physical skills are required to provide the services and products What percent of jobs are knowledge based Rule based Or Skill based Does hiring and retention practices match the job requirements ... 

Knowledge hose The knowledge base contains the encoded knowledge which is needed to solve a certain problem. The knowledge can be represented in the form of facts or rules. 

Deduction. If a knowledge-based system has a set of facts, and new facts are provided to it, then rules of inference can be appHed to the set of facts to derive conclusions. For example, from the facts that (/) hydrogen and oxygen can react explosively at high temperatures, (2) air contains oxygen,... 

Rules. Rules, first pioneered by early appHcations such as Mycin and Rl, are probably the most common form of representation used in knowledge-based systems. The basic idea of rule-based representation is simple. Pieces of knowledge are represented as IE—THEN rules. IE—THEN rules are essentially association pairs, specifying that IE certain preconditions are met, THEN certain fact(s) can be concluded. The preconditions are referred to as the left-hand side (LHS) of the rule, while the conclusions are referred to as the right-hand side (RHS). In simple rule-based systems, both the... 

Rules are cleady a usehil form of representation for knowledge-based appHcations, with their advantages of representational simplicity, wide apphcabihty, and history of past successes. However, certain important design criteria govern the proper appHcation of rules and there are shortcomings of the rule-based representation. 

MJ Sutcliffe, ERE Hayes, TL Blundell. Knowledge based modeling of homologous proteins. Part II Rules for the conformation of substituted side-chains. Protein Eng 1 385-392, 1987. 

The above results show the need to increase the level of knowledge from rules of thumb to a more rigorous scientific procedure based on validated data and design methods. 

In the case of the CPI, there are relatively few situations where control room workers are likely to face continuous periods of overload. However, when overload does occur it is likely to be associated with situations when the plant is in an unusual or abnormal state for which the workers may not have any rules or procedures available. In these situations, knowledge-based processing (see Section 2.6.2), which needs considerable mental resources, will be required and errors of diagnosis are likely to occur. 

---