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TABLE 2
Most Common Relations in ES
 
Relation type Description Example
 
Equivalence Establishes the equality or equivalence between two apparently different expressions Profit = Income - Expenses
Taxonomic Classifies a specific concept as part of a general concept A is B
    A can be classified as B, C, or D
Structural Describes how a concept or a system of concepts can be decomposed into parts or subsystems A is part of B
A is composed of B and C
    A forms part of B
    A is disjunct of B
    A is not disjunct of B
    A are mutually B disjunct
    A and B are exhaustive partitions of C
    A and B are partitions of C
Dependence Special type of relation ranging from an association, through responsibilities, parenthood, property, etc., to participation A is part of B
A and B are associated to build B
A is responsible for B
Topological Describes the spatial distribution of physical concepts and interconnections between these concepts A is to the right of B
A is above B
    A is below B
    A is inside B
    A contains B
    A intersects B
    A is connected to B
    A is in contact with B
Causal Describes how given states or actions induce other states or actions A is the cause of B
A needs B
    A fires B
Functional Describes the conditions for actions and reactions to take place and possible consequences of the actions A enables B
    A needs B
    A fires B
Chronological Describes the time sequence in which events occur A occurs before B
    A occurs after B
    A and B occur simultaneously
    A occurs during B
    A starts before B ends
Similarity Establishes which concepts are equal or analogous and to what extent Valve A is open = admits petrol
Conditional Defines the conditions in which given things take place For highly accelerated small masses moving at low speed, use quantum hypotheses
Purpose Establishes the whys and wherefores of concepts Codes were created by human beings to transmit ideas

Finally, there are functions. These are special cases of relations whose prima facie result is only a value, which, owing to their importance and specificity, should be considered separately. Examples of functions are:

  • Mother-of: Person —> Woman
  • Squared: Number —> Positive-Number
  • Car_Price: Model × Year × No. kilometers —> Price

A function is, therefore, a second type of interrelation between concepts in a universe of discourse. Although many functions can be defined for a given set of concepts, usually, some functions are stressed and others ignored in order conceptualize part of the world. The set of stressed functions in a conceptualization is called a basic functional set.

By defining the concepts, relations, and functions, the conceptual model also shows the sequence of steps according to which the expert will execute his/her task, the inferences made, and the processing of data, news, and knowledge, that is, information, used. That is, this model represents how the expert, in this case the diagnostician, behaves when resolving the tasks at hand, describing what expert knowledge and where, how, when, why, and for what purpose it comes into play in performing the task.

Conceptualization presupposes the existence of information obtained by means of what is referred to in KE as knowledge acquisition (KA). These can be acquired from documents and recordings containing explicit information, a process known as knowledge extraction, or from the expert(s), a process called knowledge elicitation. Elicited knowledge is not explicit; it is what the expert has internalized and what makes up the expert's true expertise. Document analysis, classification, etc., are techniques used for extraction, whereas other techniques, including protocol analysis, repertory grid, etc., are used for elicitation.

When the knowledge has been acquired, it has to be analyzed, organized, classified, and, finally, structured to model diagnostician behavior. This consists of a two-stage process, as shown in Figure 3.

The first stage consists of an activity of analysis, whereas the second centers on synthesis. This section discusses how to detect strategic, tactical, and factual knowledge and meta-knowledge during the analysis stage and how, in the synthesis stage, the above knowledge will have a bigger or smaller part in the static and dynamic models integrated into the knowledge map and constituting the conceptual model of the system.

Pursuant to the above, the steps to be taken to produce an external conceptualization or representation of the knowledge, taking into account the items shown in Figure 3, are as follows:

  • Analyze the acquired knowledge to identify strategic, tactical, and factual knowledge and meta-knowledge;
  • Identify concepts and record their attributes and associated values in a concept dictionary; that is, build a static model. This is an extremely important, but difficult task, because, as Plato said, anyone capable of making good definitions and classifications should be considered a god.
  • Establish the dynamic process and control model.
  • Design the knowledge map.
  • Structure and model knowledge, examining segmentation.
  • Produce the conceptual model on the basis of all the above components. That is, the conceptual model is the structured integration of the static and dynamic models and the knowledge map of each problem segment, provided it can be segmented and decomposed.


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