1 / 11

Informationsprocesser

Informationsprocesser. Kybernetik, informationsvidenskab og computerens fødsel. Definitioner af kybernetik. "the science of control and communication in the animal and the machine"- Norbert Wiener "Cybernetique: the art of governing or the science of government" - A.M. Ampere

nova
Download Presentation

Informationsprocesser

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Informationsprocesser Kybernetik, informationsvidenskab og computerens fødsel Tekno-logos 24/9-02

  2. Definitioner af kybernetik • "the science of control and communication in the animal and the machine"- Norbert Wiener • "Cybernetique: the art of governing or the science of government" - A.M. Ampere • "a branch of mathematics dealing with problems of control, recursiveness, and information" - Gregory Bateson • "Cybernetics is the science of unseen processes which energize dynamic entities: man-made, natural, and spiritual. In a narrower technical view, cybernetics are what makes systems function." - Charles A. Fink • "Should one name one central concept, a first principle, of cybernetics, it would be circularity." - Heinz von Foerster Tekno-logos 24/9-02

  3. Ross Ashby (1903-1972) • Kybernetik  Alle tænkelige maskiner • Geometri  Alle tænkelige objekter •  Biologi: samme (organisations-)principper i alt liv • Angår systemers opførsel og dynamik: “It does not ask “what is this thing”? but “what does it do”? • ikke energi eller materialitet: “Cybernetics might...be defined as the study of systems that are open to energy but closed to information and control”. Tekno-logos 24/9-02

  4. Ross Ashby • Feedback (dynamik) • Homeostasis (ligevægt) • State (tilstand) • State-space (mulige tilstande) • Trajectory (udvikling) 2 1 3 Tekno-logos 24/9-02

  5. The Watt Governor • Pre-kybernetisk feedback regulator • Dynamisk, ikke-computationel • ≈ Termostat Tekno-logos 24/9-02

  6. Informationsteori • Claude Shannon (1917-2001): Ingeniør på Bell Labs: Telefonkablers kapacitet • Information: Sum af sandsynligheden af signalets elementer (I = -  p(si)[log(si)]) • Information hviler på valg (forskel: ’K’, ikke et af de 28 andre bogstaver) • Entropi: Jo flere mulige mikro-tilstande, des mere information/entropi (mulige tal  ’190’/mulige partikelditributioner  190 C) Tekno-logos 24/9-02

  7. Informationsteori • “The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point. Frequently the messages have meaning; that is they refer to or are correlated according to some system with certain physical or conceptual entities. These semantic aspects of communication are irrelevant to the engineering problem. The significant aspect is that the actual message is one selected from a set of possible messages“ Shannon 1948 Tekno-logos 24/9-02

  8. Information • Kvantitativt: information angår ikke mening • Information er kontekstuafhængig • Information er ikke, hvad der ‘bliver sagt’, men hvad der ‘kan siges’ Tekno-logos 24/9-02

  9. Alan Turing (1912-1954) • Engelsk logiker • Bryder nazisternes kodesystem Enigma • Står fader til datalogi (computation) og AI (og biologisk morfologi) Tekno-logos 24/9-02

  10. Turing-maskine • Imaginær maskine: Software • Hoved til aflæsning og indkodning (1) • Strimmel med binære koder (2) • “Table of behaviours” • Tre parametre: • Tilstand (eks.: 011) • Kode på strimmel (eks.: 0) • Instruktion (eks.: Hvis tilstand A, og kode 1 så skriv 0 og gå 3 felter til højre) 1 2 Tekno-logos 24/9-02

  11. Den moderne computer • 1941: Radiorør ( ‘Bug’) • 1956: Transistorer • 1958: Mikrochip • 1970: Netværk • 1971: Universel mikrochip • 1979: Laptop • 1981: PC • 1984: Grafisk brugerflade (Macintosh) • 1992: PDA • 2002  Disappearing computers? Tekno-logos 24/9-02

More Related