# Information / Cybernetics

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Information / Cybernetics. Robin Burke GAM 224 Winter 2008. Outline. Reaction Papers Probability and Information Theory Cybernetics Feedback loops Homework #2. Admin. 1 st Reaction paper due Tuesday For maximum credit use some idea from the book look for an information economy - PowerPoint PPT Presentation

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Information /CyberneticsRobin BurkeGAM 224Winter 20081OutlineReaction PapersProbability and Information TheoryCyberneticsFeedback loopsHomework #22Admin1st Reaction paper due TuesdayFor maximum credituse some idea from the booklook for an information economyfeedback loopsa system of signs for the playeretc.

3UncertaintyMany games are probabilisticroll the diceshuffle the cardsSome games are notChessCheckersDots and Boxes4Certainty vs uncertaintyCertaintythe condition when the outcome of an action is known completely in advance.Some games operate this wayChessDots and BoxesBut even thenuncertainty about who will winotherwise what is the point?5ProbabilityProbability is the study of chance outcomesoriginated in the study of gamesBasic ideaa random variablea quantity whose value is unknown until it is "sampled"the random variable has a distributionfor each possible valuea probability that the value will occur6Single DieRandom variable# of spots on the side facing upDistribution1...6each value 1/6 of the timeSame event, different random variableodd or even # of dots7Two diceRandom variablesum of the two die valuesDistribution2, 12 = 1/363, 11 = 1/184, 10, = 1/125, 9 = 1/96, 8 = 5/367 = 1/6Non-uniformnot the same as picking a random # between 2-12dice games use this fact8Role of ChanceChance can enter into the game in various waysChance generation of resourcesdealing cards for a game of Bridgerolling dice for a turn in BackgammonChance of success of an actionan attack on an RPG opponent may have a probability of succeedingChance degree of successthe attack may do a variable degree of damage9Role of Chance 2Chance changes the players' choicesplayer must consider what is likely to happenrather than knowing what will happenChance allows the designer more latitudethe game can be made harder or easier by adjusting probabilitiesChance preserves outcome uncertainty with reduced strategic inputexample: Thunderstorm10PsychologyPeople are lousy probabilistic reasonersWe overvalue low probability events of high risk or rewardExample: Otherwise rational people buy lottery ticketsWe assume success is more likely after repeated failureExample: "Gotta keep betting. I'm due."Impacts for game design

11Information TheoryThere is a relationship between uncertainty and informationInformation can reduce our uncertaintyExampleThe cards dealt to a player in "Gin Rummy" are private knowledgeBut as players pick up certain discarded cards from the pileIt becomes possible to infer what they are holding12Information Theory 2Classical Information TheoryShannonInformation as a quantityhow information can a given communication channel convey?compare radio vs telegraph, for examplemust abstract away from the meaning of the informationonly the signifier is communicatedthe signified is up to the receiverInformation is measured in bitshow many choices the receiver must choose from in interpreting the message13NoiseNoise interrupts a communication channelby changing bits in the original messageincreases the probability that the wrong message will be receivedRedundancystandard solution for noisemore bits than required, ormulti-channel

14ExampleLegend of Zelda: Minish CapMonsters are not all vulnerable to the same types of weapons10 different weapons(we'll ignore combinations of weapons)Encounter a new monsterwhich weapon to use?4 bits of unknown informationWe could try every weaponbut we could get killed15Example, cont'dMessagesthe monster iconography contains messagesrocks and metal won't be damaged by the swordflying things are vulnerable to the "Gust Jar"etc.the game design varies the pictorial representations of monstersknowing that these messages are being conveyedlearning to interpret these messagesis part of the task of the playeronce mastered, these conventions make the player more capableOften sound and appearance combinea redundant channel for the information16Information FlowPeople exchange information with a game systemto figure out options and outcomesBut a game system can use information flow internally as wellNorbert Weiner developed cybernetics to explain this type of systemCybernetics is an attempt to unify the study of engineered and natural systems17Cybernetic SystemsCybernetics is about controlHow is the behavior of a system controlled?Control implies that there are parameters that should be maintainedExample: temperaturehuman bodycar engineControl implies informationTemperature messages"too high""too low""OK"

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