Artificial Intelligence Course outline Introduction Problem solving Generic algorithms Knowledge Representation and Reasoning Expert Systems Uncertainty Learning Planning Advanced topics in AI CIIT Sahiwal

Artificial Intelligence Problem Solving and Search Muhammad Ejaz CIIT Sahiwal

Problem Solving The mechanism to find the goal performing some actions to transit from one state to another is known as problem solving. Initial state Operator: description of an action State space: all states reachable from the initial state by any sequence action Path: sequence of actions leading from one state to another Goal test: which the agent can apply to a single state description to determine if it is a goal state Path cost function: assign a cost to a path which the sum of the costs of the individual actions along the path. CIIT Sahiwal

Different types of problem Well structured problems  When problem description and its rules are described clearly and unambiguously. Ill structured problem  No extra information about the problem other than the definition No extra information No heuristics (rules) CIIT Sahiwal

Well Defined Problems Finding the maximum from a sequence of integers. Eight puzzle 1,2 or 2,1 puzzle Farmer and goose problem Water pouring problem CIIT Sahiwal

Eight puzzle CIIT Sahiwal

Water Pouring Problem CIIT Sahiwal

Farmer and goose problem W F ~ W F G F W F G ~ G F ~ W C W C C ~ G F G ~ C F ~ W C F ~ C F W W G ~ G G ~ G C C C F C W ~ G W CIIT Sahiwal

Think Point What will be tree representation of Farmer and goose problem? CIIT Sahiwal

Searching For Solutions Having formulated some problems…how do we solve them? Search through a state space Use a search tree that is generated with an initial state and successor functions that define the state space CIIT Sahiwal

Different search techniques Uninformed Search  Only the information available in the problem definition – Also known as blind searching -Breadth-first search -Depth-first search -Depth-limited search -Iterative deepening search Informed Search  When sufficient information is provided to reach the goal. CIIT Sahiwal

Breadth-First Search Recall from Data Structures the basic algorithm for a breadth-first search on a graph or tree Expand the shallowest unexpanded node Place all new successors at the end of a FIFO queue CIIT Sahiwal

Breadth-First Search CIIT Sahiwal

Breadth-First Search CIIT Sahiwal

Breadth-First Search CIIT Sahiwal

Breadth-First Search CIIT Sahiwal

Depth-First Search Recall from Data Structures the basic algorithm for a depth-first search on a graph or tree Expand the deepest unexpanded node Unexplored successors are placed on a stack until fully explored CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal

Depth-First Search CIIT Sahiwal