Page 23 - DCAP506_ARTIFICIAL_INTELLIGENCE

Unit 2: Problems, Problem Spaces and Search

chess coin, the goal is any board position in which the challenger does not have a legal move and Notes
his or her “king” is under attack. The legal moves offer the way of receiving from initial state of
final state.
The legal moves can be illustrated as a set of rules including two parts: A left side that provides
the current position and the right side that illustrates the change to be made to the board
position.
Current Position:
While pawn at square (5, 2), and Square (5, 3) is empty, and Square (5, 4) is empty.
Changing Board Position:

Move pawn from Square (5, 2) to Square (5, 4).
The existing position of a coin on the board is its state and the set of all possible states is state
space. One or more states where the problem finishes is final state or goal state.
The state space illustration forms the foundation of most of the AI methods. It permits for a
formal definition of the problem as the requirement to exchange some given situation into
some preferred situation by means of a set of allowable operations. It allows the problem to be
solved with the assistance of known techniques and control approaches to move via the problem
space until goal state is located.

Therefore problem as State space search can be recapitulated as:
 Formulate a problem as a state space search by displaying the legal problem states, the
legal operators, and the initial and goal states.

 A state is defined by the measurement of the values of all attributes of interest in the world.
 An operator modifies one state into the other; it has a precondition which is the value of
certain attributes previous to the application of the operator, and a set of effects, which are
the attributes changed by the operator.
 The initial state is where you begin.

Task Make distinction between closed states and open states.

Self Assessment

Fill in the blanks:
1. The thought of .............................. Search is that a problem can be solved by probing the
steps which might be taken for the solution.
2. .............................. are the States whose links have all been discovered.
3. A .............................. is defined by the measurement of the values of all attributes of interest
in the world.

2.2 Production System

A Knowledge demonstration formalism comprises collections of condition-action rules
(Production Rules or Operators), a database which is customized in harmony with the rules, and a
Production System Interpreter which manages the operation of the rules i.e. The ‘control mechanism’
of a Production System, formatting the order in which Production Rules are fired.

LOVELY PROFESSIONAL UNIVERSITY 17