PROBLEM AREAS SUITABLE FOR EXPERT SYSTEMS

10.9 PROBLEM AREAS SUITABLE FOR EXPERT SYSTEMS

Expert systems can be classified in several ways. O n e way is by the general problem areas they address. For example, diagnosis can be defined as "inferring system mal- functions from observations." Diagnosis is a generic activity performed in medicine, organizational studies, computer operations, and other fields. The generic categories of expert systems are listed in Table 10.5. S o m e ES belong to two or more of these cate- gories. A brief description of each category follows:

Interpretation systems infer situation descriptions from observations. This category includes surveillance, speech understanding, image analysis, signal interpretation, and many kinds of intelligence analyses. An interpretation system explains observed data by assigning them symbolic meanings describing the situation.

Prediction systems include weather forecasting, demographic predictions, economic forecasting, traffic predictions, crop estimates, and military, marketing, and finan- cial forecasting.

Diagnostic systems include medical, electronic, mechanical, and software diagnoses. Diagnostic systems typically relate observed behavioral irregularities to underly- ing causes.

Design systems develop configurations of objects that satisfy the constraints of the design problem. Such problems include circuit layout, building design, and plant

TABLE 1 0 . 5 Generic Categories of F.xpcrl Systems

Category Problem Addressed Interpretation

Inferring situation descriptions from observations Prediction

Inferring likely consequences of given situations Diagnosis

Inferring system malfunctions from observations Design

Configuring objects under constraints

Planning

Developing plans to achieve goals

Monitoring Comparing observations to plans, flagging exceptions Debugging

Prescribing remedies for malfunctions

Repair Executing a plan to administer a prescribed remedy Instruction

Diagnosing, debugging, and correcting student performance

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layout. Design systems construct descriptions of objects in various relationships with o n e another and verify that these configurations conform to stated con- straints.

Planning systems specialize in planning problems, such as automatic programming. They also deal with short- and long-term planning in areas such as project man- agement, routing, communications, product development, military applications, and financial planning.

Monitoring systems compare observations of system behavior with standards that seem crucial for successful goal attainment. These crucial features correspond to potential flaws in the plan. There are many computer-aided monitoring systems for topics ranging from air traffic control to fiscal management tasks.

Debugging systems rely on planning, design, and prediction capabilities for creating specifications or recommendations to correct a diagnosed problem. Repair systems develop and execute plans to administer a remedy for certain diag- nosed problems. Such systems incorporate debugging, planning, and execution

capabilities. Instruction systems incorporate diagnosis and debugging subsystems that specifically address the student's needs. Typically, these systems begin by constructing a hypo- thetical description of the student's knowledge that interprets her or his behavior. They then diagnose weaknesses in the student's knowledge and identify appropri- ate remedies to overcome the deficiencies. Finally, they plan a tutorial interaction intended to deliver remedial knowledge to the student.

Control systems adaptively govern the overall behavior of a system. To do this, the control system must repeatedly interpret the current situation, predict the future, diagnose the causes of anticipated problems, formulate a remedial plan, and mon- itor its execution to ensure success.

Not all the tasks usually found in each of these categories are suitable for expert systems. However, there are thousands of decisions that do fit into these categories.