Information theory andcybernetics

Following a review oftermsusedininformationscription bya realizable modelhastheadvantages of theory, conventional communications systems are beingquantitative andcomplete (whichdoesnotyet examined. Functional models that leadtoastatistical meanexactitude), andcompels onetouseaneconomic impulse generator aredeveloped foraneuron anda methodofdescription because ofthecostfactor. Itis fish. Theproblems ofinformation generation, reduc- truethatthere isthedanger thatthemodelmaybean tion, andstorage inmanareconsidered. Theconcept oversimplification ofthephysical system that itdescribes. ofbidirectional communication isadvanced where Duringtheestablishment ofsuchmodels, acontinuous thereceiver aswellasthetransmitter isactive and andclose contact istherefore required between thecomthetheory ofbidirectional communication isshownto munications engineer andbiologist-an example ofthe beageneralization ofShannon's information theory. bridge between sciences incybernetics. According toNorbertWiener, cybernetics isthe Information, transinformation, and science ofregulation andcontrol inorganisms andma- channelcapacity chines. Intoday's terms, cybernetics canmoregenerallyShannon's information theory (1948) permits aquanbedefined asthescience ofmessage transmission, process-titative description oftheinformation content ofamesing, andtheregulation andcontrol ofcomplex systems age.IfP1denotes probability ofacertain symbolxat such asautomatic devices andorganisms. Interms ofsub- thetransmitter, information content 1xisdefined by ject matter, according tothis definition, cybernetics isnot I,= ld(l/px) bits actually anewscience because theareasofresearch include control andmessageprocessing. Theimportant characteristic ofcybernetics isthatproblems aretreated A highly unpredictable message ischaracterized by byaractherisam metod cybernetics cshan terolefore breaa large information content; a predictable messagehas bythesamemethods; cybernetics cantherefore becon- sml inomto cotn.Teifraincnettu ** ** 1 t1 * T * 1 1 ~~~small information content. TheInformation content thus sidered asabridge between sciences. Inparticular, the indicates theuncertainty ofthemessage fromthetransmethods developed incommunications technology are mitter thatiseliminated byitstransmission tothereeminently suitable fordescribing complexsystems. While commuicationsr deasc with thetra isysi ad.ceiver. Theaverageinformation content ofa message, Whilecommunications deals withthetransmission anda nrp sotie yfriga vrg au