The Current State of Human-Level Artificial Intelligence in Computer Simulations and Wargames

An Intelligent Action Algorithm for Virtual Human Agents. Undeger; Isler; Ipekkan (2001)

Type of Research: Academic probably funded by military.

Summary:
This article presents a method for moving intelligent agents across a 3D landscape towards a common goal.

Part of this problem, of course, includes determining Line of Sight (LOS) for the agents.

The algorithm for individual agent movement is:

Main loop

For each group
For each agent

          If the agent is a red team member (intelligent agent)
               Construct the sensor detection list (perceptions) for the agent; > (A)
               Analyse the detected list and update the knowledgebase; > (B)
               Execute behavior module; > (C)

Update the pysical appearance;

Backup the previous detected list and create a new list;

For each group
For each agent (target) except himself
Calculate the seeing and hearing statistics between the agent and the target; > (D)

For each member of detected list

If the detection exists in the previous list and unsensed because of the probability test and no probability change occurred after that time

Mark the member of new detected list as “unsensed”;

For each sensed member of new detected list

Do a comparison to knowledgebase, find the similarities;

If similarity found

Update the knowledge and check the member of detected list as “similarity_found”;

For each member of new detected list which is not checked as “similarity_found”

Do a probability test and if it is passed
Add the list member to the knowledgebase as a new perception;
Else
Check the member of detected list as “unsensed”;

Find who the commander is;
Find the status of the mission plan;
If the agent is a commander

If there is no abnormal condition

Follow the path;
Else
Execute the reaction planning module;

Else

If there is no abnormal condition

If the commander position is known

Follow the commander;

Else

Stop and search for the commander;

Else

Execute the reaction planning module;

Compute the statistics between the agent and the target (line of sight, viewing angle, range, etc.);

If there is any possibility of detection, add the perception to the detected list;

Comments:
The authors are using a DTED map file and seem to have duplicated much of the work that my group and I completed in 1995 for The War College (below):

They also use an extremely simplified movement matrix (1 movement point when crossing an embedded graph cells vertically or horizontally and 1.4 movement points when crossing a cell diagonally). They do not factor in any terrain costs (woods versus grassland versus swamp, etc.). They do, however, calculate slope and adjust movement accordingly.

Their algorithm for coordinated agent movement follows:

Description	Peusedo Code
Create the world database. Create the DTED matrix	cPlatoon * plt; cAgent * agent; cGoalPoint * point; cGoalItem * item world->Initialize(); world->Create_World(...); world->Create_DTED(...);
Add a group and two agents to the environment	plt = world->Add_Group( GroupRed ); agent = plt->Add_Agent(...); agent = plt->Add_Agent(...);
Set group position and formation of the agents	plt->SetGroupPosition( 9163.0, 10259.0 ); plt->Set_Agents_Group_Formation(8,true);
Get the starting control point. Add a goal item for the point. Move fast to the next point	point = plt->plt_goals->GetObjectFromIndex(0); point->movingstate = MovingFast;
	Goal item 1.1	Item=point->Add_GoalItem(giWaitUntilReceiveKeyword); item->data.ReceiveFromID = 1; item->SetKeyword("First Step Go...");
Add a control point	point = plt->Add_Plt_GoalPoint( gpPassThrough, 9345.0, 9742.0 ); point = plt->Add_Plt_GoalPoint( gpTactical , 9220.0, 9595.0 );
Add a tactical control point. Wait until the group 2 leaves from point 3	point = plt->Add_Plt_GoalPoint( gpTactical , 8945.0, 9270.0 );
	Goal item 3.1	item= point ->Add_GoalItem(giWaitUntilContinueMission); item->data.ReceiveFromID = 2; item->data.GoalPointID = 3;
Add another tactical control point. Wait until group 1 arrives at point 5. When ready to continue, send a keyword to group 1. Wait for a response from group 1 to leave the point. Move slow to the next point	point = plt->Add_Plt_GoalPoint( gpTactical , 8945.0, 9270.0 ); point ->movingstate = MovingSlow;
	Goal item 4.1	item = point ->Add_GoalItem(giWaitUntilArrival); item->data.ReceiveFromID = 1; item->data.GoalPointID = 5;
	Goal item 4.2	item = point ->Add_GoalItem(giReadyToContinueDo); item->data.doAction = doSendKeyword; item->data.SendToID = 1; item->SetKeyword("Group 3 Ready");
	Goal item 4.3	item = point ->Add_GoalItem(giWaitUntilResponseKeyword); item->data.ReceiveFromID = 1; item->SetKeyword("Mission Start");
Add the target point. Put a bomb to the point and move fast after leaving. While leaving the point send the keyword “mission completed”	point = plt->Add_Plt_GoalPoint( gpTarget , 8935.0, 9130.0 ); point ->movingstate = MovingFast;
	Goal item 5.1	item = point ->Add_GoalItem(giArrivalDo); item->data.doAction = doPutBomb;
	Goal item 5.2	item = point ->Add_GoalItem(giContinueMissionDo); item->data.doAction = doSendKeyword; item->data.SendToID = -1; item->SetKeyword("Mission Complete");
Add another control point	point = plt->Add_Plt_GoalPoint( gpPassThrough, 9212.0, 9124.0 );
Home point	point = plt->Add_Plt_GoalPoint( gpHome , 9683.0, 8400.0 );

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