An Elementary NavigationAn Elementary NavigationSimulated in JavaSimulated in Java

Presented by Jinho D. Choi

Artificial IntelligenceArtificial Intelligence

Artificial Intelligence- A branch of computer science dealing with the simulation of intelligent behavior in computers

Artificially Intelligent Car- A car that can move safely without human driving

Simulation- An examination of a problem often not subject to direct experimentation

Solving a mazeSolving a maze Maze

- A confusing intricate network of passages

Brain vs. Recursive Algorithm Base part

- Whether or not you reach the exit Recursive part

- Where to go in order to reach the exit

- Moving to an empty cell- Backtracking

boolean solveMaze(var maze, var location){ if (reach the goal)

return true; else {

// moving to an empty cellif ((down-cell is empty) || (right-cell is empty) || (up-cell is empty) || (left-cell is empty)){ maze[location] = ‘X’; // mark the location

  if (down-cell is empty)

return solveMaze(maze, down-cell); else if (right-cell is empty)

return solveMaze(maze, right-cell); else if (up-cell is empty)

return solveMaze(maze, up-cell); else if (left-cell is empty)

return solveMaze(maze, left-cell);}// backtrackingelse if ((down-cell is marked) || (right-cell is marked) ||

(up-cell is marked) || (left-cell is marked)){ maze[location] = ‘#’; // block the location

  if (down-cell is marked)

return solveMaze(maze, down-cell); else if (right-cell is marked)

return solveMaze(maze, right-cell); else if (up-cell is marked)

return solveMaze(maze, up-cell); else if (left-cell is marked)

return solveMaze(maze, left-cell); else

return false; // path does not exist}

}}

Solving a maze with the fixed entry and exitSolving a maze with the fixed entry and exit

‘Finding an empty cell’ vs. ‘Backtracking’ Right, Down direction vs. Left, Up direction

r, cr

r+ 1

r-1

c c+ 1c-1.***.....**.***....****.*.**.*.*.******...******.

boolean solveMaze(int r, int c){ if (r == MAX-1 && c == MAX-1)

return true; // reaches the exit else if (maze[r+1][c]=='.') || (maze[r-1][c]=='.') ||

(maze[r][c+1]=='.') || (maze[r][c-1]=='.')) {

maze[r][c] = '+'; // moves to an empty cell

if (maze[r+1][c] == '.') r++;else if (maze[r][c+1] == '.') c++;else if (maze[r-1][c] == '.') r--;else if (maze[r][c-1] == '.') c--;

} else {

maze[r][c] = '-'; // backtracks

if (maze[r+1][c] == '+') r++;else if (maze[r][c+1] == '+') c++;else if (maze[r-1][c] == '+') r--;else if (maze[r][c-1] == '+') c--;else return false; // no path exists

}

return solveMaze(r, c);}

Examples 1.1

Solving a maze with the unfixed entry and exitSolving a maze with the unfixed entry and exit

Unfixed Entry- Can be located at any cell before the program begins

Ordering in backtracking- Left, Up, Right, Down- Code 1.1- Example 1.2- Example 1.3

Finding the best path through a mazeFinding the best path through a maze

Priority of 4 directions- right, down, up, left- Example 1.4

Permutation of 4 numbers- Code 1.2

Convert numbers to directions- (0, 1, 2, 3) to (up, down right, left)- Code 1.3

Count the steps- Code 1.4 Example 1.5

Driving on a street I (A single Driving on a street I (A single car)car)

Map- A representation usually on a flat surface of the whole or a part of an area

Speed limit, stop signs, traffic signals

Speed limitsSpeed limits

Cruise control Physics Problems

- Acceleration & Deceleration

- Rotational Energy

- Frictions

- Example 2.1

Visiting a placeVisiting a place

Map of ‘Jinho City’- Coe, Eby, H Mart, and St. Lukes

Representations- building, null, up, right, down, and left

Database for places Code 2.1 Example 2.2

int iMap[][] = {{0, 0, 4, 1, 0, 0, 2, 0, 0},

{0, 1, 4, 1, 4, 2, 2, 1, 0},

{5, 5, 4, 5, 5, 5, 5, 5, 5},

{3, 3, 4, 3, 3, 3, 2, 3, 3},

{0, 5, 4, 0, 0, 0, 2, 1, 1},

{0, 3, 4, 0, 0, 0, 2, 5, 0},

{1, 1, 4, 0, 0, 0, 2, 3, 0},

{0, 0, 4, 2, 4, 1, 2, 0, 0},

{0, 0, 3, 3, 3, 3, 2, 1, 0}};

Stop signsStop signs

Only one object- No need for stop signs

Location of stop signs Pause for ½ second Example 2.3

Traffic signalsTraffic signals

Properties- Horizontal & Vertical- Take turns about 10 sec.- Sense 2 blocks before

Database for traffic signals- Code 2.2

Synchronization- Code 2.3

Example 2.4

Driving on a street II (Multiple Driving on a street II (Multiple cars)cars)

A good beginning for an artificial intelligent car Less flexibility vs. more safety Convenient for humans, beneficial for society

Three moving objectsThree moving objects

Object 1, Object 2, and Object 3

Database for the objects- Code 3.1

Keeps the traffic signals- Code 3.2

Example 3.1

Visiting a place against 3 other objectsVisiting a place against 3 other objects

Chance for the intersections- Code 3.3

Stop signs- Check if the street is clear- Code 3.4

Example 3.2

Day and night situationsDay and night situations

Turn on the headlights

Slow down

Example 3.3

AppendixAppendixBlackjack Chess

4 / 4 Puzzle Elephant Spinout

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