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3.3. IDENTIFICATION OF STRATEGIC, TACTICAL, AND FACTUAL KNOWLEDGE

As several authors, and Scott et al. (Scott et al., 1991) with whom we largely agree, rightly pointed out, the first thing to look for is strategic knowledge and meta-knowledge to produce a clear definition of the modular steps making up the expert's task. Modularity is important because it enables each module to be addressed separately, there being no collateral effects nor interrelations between each module, as they are disjunct. Second, it also defines the control flow that will take place within the ES. This knowledge can then be synthesized, restructuring, where necessary, the different parts, modules, or subtasks making up the system.


FIGURE 3 Analysis and synthesis for conceptualization.

So, it is important first of all to identify and establish a very detailed sequence of actions executed by the expert and to be executed by the ES. We can start by revising the low-level actions performed by the expert and try to describe them very generally. This description should include actions considered significant by the expert. Each action should be a functional unit that can be implemented and verified separately, hence the name of modular step. The actions in this description correspond with the high-level steps to be executed by the ES.

These steps have to be numbered and then organized, using one or more external or intermediate representation(s): organizational chart, heterarchical graphs, hierarchical trees, etc., illustrating the manner in which the ES should execute the above steps. If the current system development cycle does not cover the whole task, it is important to ensure that the representation also includes the omitted subtasks. That is, the following actions will be performed:

  • Describe what the expert does and the ES should do in the step.
  • Identify the substeps corresponding to the actions in the description.
  • Number the substeps.
  • Use an external representation to illustrate the manner in which the expert executes and the ES is to execute the substeps.

The above high-level steps then have to be decomposed recursively into as many substeps as necessary. This involves studying what the expert did and what the ES is to do until we fully understand the step. Then any step composed of more than a small number of input actions, reasoning modes, and output actions has to be subdivided. The preceding process has to be repeated to subdivide a step.

Then, each of those substeps are revised to see whether any or all can be further decomposed. If they can be decomposed, the process has to be repeated as many times as necessary. If a lot of substep decomposition levels are defined, we will need to draw a functional decomposition tree, if the structure is hierarchical, or a diagram or net, if it is heterarchical, to illustrate how the task executed by the expert and to be executed by the ES can be decomposed into smaller steps. The tree or net starts with the node corresponding to the complete expert/ES task.

Early ES sought to assist physicians in diagnosing and curing certain diseases. Therefore, an example from the medical field has been chosen to illustrate this part of conceptualization: diagnosis of malaria. In this case, the first thing the expert does is to study the patient's clinical record, then he/she tries to diagnose the disease and, finally, tries to cure the patient. So, as regards the definition of high-level steps, the expert's work is composed of four major steps: anamnesis, studies of signs and symptoms, diagnosis and treatment, which are then decomposed into the following substeps.


FIGURE 4 Functional decomposition tree.

  1. Patient anamnesis; that is, consider latest trips, vaccines, allergies, diseases
  2. Study the patient considering his/her case history; that is, establish the symptoms (appearance, pain, etc.), take a sample of blood and do a test
  3. Diagnosis; that is, formulate, test and confirm hypotheses
  4. Prescribe treatment; that is, select the medicines to cure the disease or relieve the symptoms, infer the treatment considering allergies and age (for dosage)


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