Artificial Intelligence (AI)

 

"I have seen few games, if any, that had any challenging AI. Most games either had an AI that cheated (Civilization), had a really dumb AI with scenarios in which the human players were put at a disadvantage (Age of Empires), or had a very predictable AI (Settlers)" (Marco Veldman, game designer)


Multiplayer Creativity vs. AI

Exp:WW2 is not designed primarily as a single player game. The reason for this is that single player games need a good computer opponent and this requires good artificial intelligence (AI). So far their have been not been any complex strategy games that have provided players with a very challenging AI. Usually, the excuse for poor AI performance has been that programmers haven't been given the time to develop the AI. This is not, to my opinion, the main reason for poor AI performance. I strongly believe that human creativity is much more capable of providing a challenge than AI. Humans can adapt and learn quickly from each other and will therefore be less predictable.
Despite this, Expansion is not devoid of AI, since I also believe in giving players the capability of not having to know about all military, political or economic details.

Artificial Intelligence

Within the realm of Artificial Intelligence (AI), there are different ways of translating input (the situation on the battlefield, for instance) into output (the strategy or tactic to be employed). One such way is through the use of Fuzzy State Machines (FuSM). Contrary to the Finite State Machine (FSM) which needs specific input and produces specific output, the FuSM is capable of producing different output under the same circumstances. So, whereas a FSM's response is always predictable, that of a FuSM is merely plausible, so it could react flexibly to changing situations. Expansion uses two FuSMs: the Supreme Commander and the Battle Commander.


The Supreme Commander

Of the two AI components of Expansion, the Supreme Commander is used to perform most of a players's job. For a player interested in military affairs, the Supreme Commander will not be needed. This component is useful, however, as either a computer opponent or to do (some of) the work of a player not so much interested in military affairs.

What the Supreme Commander does is to get a general overview of the battle field and to decide which battle commanders should attack, defend, recruit, rest, or make any other strategic decision. These decisions are based upon an analysis of the world known to the Supreme Commander, on the commander's character, and on the options a player sets for determining strategy. Basically, the Supreme Commander's job seems simple: have Battle Commanders attack where enemy resistance is likely to be small and have them defend elsewhere. But this takes quite a lot of analyzing. How do we define our own strength and that of the enemy? Where is resistance likely to be small? Is a large army at the other side of the English Channel a danger or not? These are some of the questions the Supreme Commander needs to answer.


The Battle Commander

The other component of the AI within Expansion, is called the Battle Commander. While there is only one Supreme Commander, there will most likely be several Battle Commanders. These control the armies, fleets or air fleets and are known as generals, admirals, or air marshalls, but we will simply refer to them as commanders. Just as with the Supreme Commander, Battle Commanders are able to take over from humans. Well, more or less, since I still hold the belief that human creativity can never be replaced by computer power. So I suggest planning most of your campaigns yourself.

Whereas the Supreme Commander makes strategic decisions, Battle Commanders make tactical decisions. When giving orders, players can simply choose any of the generic options (Commander Decides, Attack, or Defend) to activate a Battle Commander. If the Commander Decides option has been chosen, the Battle Commander will do the job of the Supreme Commander, but on a smaller scale: just for his own army. The result will be the decision to attack or defend.

The other generic options, given to the Battle Commander by either the player, the Supreme Commander, or by himself when forced to by the Commander Decides option, will make the Battle Commander decide a more detailed tactic. For example: a player gives orders to an army, but chooses the option Commander Decides. The Battle Commander will analyse his situation and decides to choose the option to Defend. The next step is that the commander has to choose a more detailed defense tactic. The Defense in Depth tactic is chosen by the Battle Commander.

How does a Battle Commander reach that decision? The answer is still debatable. It involves assessing the strength of nearby friendly and enemy units and taking into account the different unit types employed. With the means at hand, the goal (given by the player or the Supreme Commander) should be reached. If the odds are against him, the Battle Commander will either defend or retreat.


Summary

Expansion Games is dedicated to bringing games that will eventually have a challenging AI. This will be achieved through a gradual incorporation of :

  • a neural net with continuous learning
  • an even faster learning by analysis of moves made by succesful players
  • a multi-level AI, by having different AI algoritms for the strategic and operational levels
  • appointments of hotspots: analysis of a map where the AI goals are shown
  • influence mapping: analysis of a map where the strength and weaknesses of friendly and enemy forces are seen
  • a threaded AI: when the program waits until a player ends his turn, it will use that time to 'think'
  • a historic database

Game Organization



Encyclopedia

This historical conflict simulation is dedicated to Chanel Stevens

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© 1999-2005 M.C. Veldman, Expansion Games

Acknowledgements