DOCSLIB.ORG

A Model to Explore Multidimensional Homeostasis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Model to Explore Multidimensional Homeostasis The Daisystat: A model to explore multidimensional homeostasis James Dyke Max Planck Institute for Biogeochemistry, 07745 Jena, Germany [email protected] Abstract over aeons whereas the Homeostat was built from four de- commissioned Royal Air Force bomb aiming devices and The Homeostat was a physical device that demonstrated operated at millisecond speed) both systems exhibit very Ashby’s notion of ‘ultrastability’. The components interact in such a way as to maintain sets of essential variables to similar behaviour that can be observed in the Daisystat. within critical ranges in the face of an externally imposed In the following sections, the Homeostat and Daisyworld regime of perturbations. The Daisystat model is presented models will be described. The Daisystat is then presented that bears a number of similarities to Ashby’s Homeostat but and two sets of results shown. The first set shows how a which can also be considered as a higher dimensional version single-environmental-variable-Daisystat responds to a pro- of the Watson & Lovelock Daisyworld model that sought to explain how homeostasis operating at the planetary scale may gressive driving perturbation, the second set shows how a arise in the absence of foresight or planning. The Daisystat four environmental variable Daisystat responds to instanta- model features a population of diverse individuals that af- neous shocking perturbations. The establishment and main- fect and are affected by the environment in different ways. tenance of homeostasis in both cases is given in terms of The Daisystat model extends Daisyworld in that homeostasis ‘rein control’. It will be shown that the behaviour of the pop- is observed with systems comprised of four environmental variables and beyond. It is shown that the behaviour of the ulation is analogous to the behaviour of the electromechan- population is analogous to the ‘uniselector’ in the Homeostat ical Homeostat in that the volume of possible connections in that rapid changes in the population allows the system to between elements of the system is ‘searched’ until new feed- ‘search’ for stable states. This allows the system to find and back values are found that produce homeostatic states. Such recover homeostatic states in the face of externally applied a process is the result of natural selection operating on a perturbations. It is proposed that the Daisystat may afford insights into the evolution of increasingly complex systems population of diverse individuals. No notions of higher level such as the Earth system. selection, altruism or kin selection are required to explain the homeostatic behaviour of the system. The ‘law of requi- site variety’ (Ashby, 1956) is seen operating in the Daisystat Introduction in that there are lower bounds for the amount of genetic and This paper introduces a new model that demonstrates home- phenotypic diversity in the population in order for homeosta- ostasis in the face of external perturbations: the Daisys- sis to be established and maintained. It is proposed that the tat. The Daisystat is a hybrid of ‘Daisyworld’ and ‘Home- Daisystat can be used as a tool to explore the evolution and ostat’ as it shares salient features with both models. The emergence of real world complex systems such as the Earth Daisyworld model (Lovelock (1983); Watson and Love- system. lock (1983)) was initially intended as a cybernetic proof of concept for planetary homeostasis as formulated in The Homeostat Gaia Theory which proposed that the Earth system (where The Homeostat was an electromechanical device designed ‘Earth system’ is defined as the Earth’s atmosphere, oceans, and constructed by W. R. Ashby. The Homeostat consisted cryosphere, lithosphere and biota) was a homeostatic entity of four units. Each unit produced an output that was fed into that maintained conditions to within the range that allowed the inputs of the other units and back to itself via a recurrent widespread life (Lovelock, 1979). The Homeostat was a connection. Fig. 1 shows a schematic of the Homeostat units physical device that exhibited ultrastability - the ability to and their connections. The inputs into the ith unit, Ii, are the respond to a particular regime of perturbations in such ways sum of the outputs of the other units multiplied by a set of as to maintain certain essential variables to within essen- input weights: tial ranges (Ashby, 1960). While the spatial and temporal j=4 scales of Daisyworld and the Homeostat are very different X Ii = Oj!j;i (1) (Daisyworld considers self-regulation at a planetary scale j=1 1 Unit 1 Unit 2 0.5 0 Output Unit 3 Unit 4 −0.5 −1 0 50 100 150 200 250 300 Figure 1: Schematic of the Homeostat and the connections Time between units. Double arrow headed lines represent the two connections that link two units. Each unit has an output con- Figure 2: Output of the four Homeostat units. The third nection to the other three units and one recurrent connection unit (second from bottom) is perturbed at Time = 200 by to itself. decreasing its output by 1. This drives the unit outside of its essential range of [-0.5,0.5] and actuates the uniselector that where !j;i is the weight for the connection from the jth unit creates a new set of random weights. This produces large to the ith unit. A weight can either increase or decrease changes in all other units and actuation of their uniselectors a connection input. Each unit has a target value, T . The until a new stable state is achieved. unit’s output, O, is the difference between the input and tar- O = T − I get value: . This represents the first level of Daisyworld homeostatic control in the Homeostat. The second level of control is derived from the establishment of essential ranges While Daisyworld is a simple model of a planetary system, for the output of the units. If the output of a unit moves it is more complicated than the Homeostat with a number of outside of the essential range, then a uniselector component different feedback mechanisms that feature non-linear func- randomly generates connection weights for that unit until the tions. However, at its heart it is similar in that two units unit output moves back within the essential range. For ex- in the form of two species or type of plants (commonly re- ample, if the essential range is [-0.5,0.5] and O = 0:6 then ferred to as ‘daisies’) exert unidirectional effects on a regu- the uniselector would generate new weights for all connec- lated variable in the form of planetary temperature. These tions into that unit until the output moves back within the effects stem from the different albedo of the daisies. Albedo essential range. The Homeostat demonstrated ultrastability is a measure of the reflectivity of an object. Black daisies that was a consequence of Ashby’s law of requisite variety. have lower albedo than white daisies. Changing the relative In order for the Homeostat to maintain stable states in the proportion of black and white daisies will affect the plane- face of perturbations, it must be able to reconfigure itself in tary albedo and so the global temperature. The black and at least as many ways as these perturbations demand. Con- white daisies share the same parabolic growth response to sequently, the volume of possible connection weight values temperature. Both grow at maximum rates when their local must encompass all possible values that would be required temperatures are 22.5◦ Celsius with growth progressively to produce stable states. decreasing, until it is zero when the temperature is 5◦ or 40◦ Homeostat simulations start by having the uniselectors for Celsius. each unit create random weights. This produces initially Daisyworld simulations consist of seeding a grey planet chaotic behaviour whereby one unit drives another unit out that has an intermediate albedo of 0.5 with black and white of its essential range which responds with new uniselector daisy seeds. This planet orbits a star much like the sun values which may drive another unit of of its essential range which over geological time scales increases in luminosity or and so on. Given sufficient iterations of the uniselector pro- brightness. On a lifeless planet, as the star increases in lu- cess, a set of weights will be generated that proves to be minosity, the temperature increases approximately linearly stable in that the outputs of all units remain within their es- (the actual temperature response being a quartic function of sential ranges. An example Homeostat simulation is shown luminosity). The situation is markedly different when black in Fig. 2. The Homeostat finds a stable state and is then per- and white daisies are present in that the temperature rapidly turbed when Time = 200 by decreasing the output of one moves towards the maximum growth rate temperature and unit by 1. This leads to all units moving out of their es- then stays within the range that the daisies are able to grow sential range and a period of uniselector activity that creates over as luminosity increases. This demonstrates how plan- new random weights which produces a new attractor which etary regulation may emerge as a consequence of biologi- the system relaxes towards. cal activity that is not the result of intentional design and in ways compatible with natural selection. Fig. 3 shows a review. The Daisystat is intended to address one of these planetary temperature being regulated when both daisies are more important limitations that was succinctly identified by present and Fig. 4 show how this regulation is the result of J. Kirchner: the change in the proportional coverage of the black and white daisies. “Daisyworld is a one-feedback model; there is only one environmental variable and it is regulated by ex- tremely strong feedback with the simplest possible bio- 100 sphere.
Load more

Recommended publications
  • Warren Mcculloch and the British Cyberneticians
    Warren McCulloch and the British cyberneticians Article (Accepted Version) Husbands, Phil and Holland, Owen (2012) Warren McCulloch and the British cyberneticians. Interdisciplinary Science Reviews, 37 (3). pp. 237-253. ISSN 0308-0188 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/43089/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version. Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University. Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available. Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. http://sro.sussex.ac.uk Warren McCulloch and the British Cyberneticians1 Phil Husbands and Owen Holland Dept. Informatics, University of Sussex Abstract Warren McCulloch was a significant influence on a number of British cyberneticians, as some British pioneers in this area were on him.
    [Show full text]
  • “The Action of the Brain” Machine Models and Adaptive Functions in Turing and Ashby
    “The Action of the Brain” Machine Models and Adaptive Functions in Turing and Ashby Hajo Greif1,2 1 Munich Center for Technology in Society, Technical University of Munich, Germany 2 Department of Philosophy, University of Klagenfurt, Austria [email protected] Abstract Given the personal acquaintance between Alan M. Turing and W. Ross Ashby and the partial proximity of their research fields, a comparative view of Turing’s and Ashby’s works on modelling “the action of the brain” (in a 1946 letter from Turing to Ashby) will help to shed light on the seemingly strict symbolic / embodied dichotomy: while it is a straightforward matter to demonstrate Turing’s and Ashby’s respective commitments to formal, computational and material, analogue methods of modelling, there is no unambiguous mapping of these approaches onto symbol-based AI and embodiment-centered views respectively. Instead, it will be argued that both approaches, starting from a formal core, were at least partly concerned with biological and embodied phenomena, albeit in revealingly distinct ways. Keywords: Artificial Intelligence, Cybernetics, Models, Embodiment, Darwinian evolution, Morphogenesis, Functionalism 1 Introduction Not very much has been written to date on the relation between Alan M. Turing and W. Ross Ashby, both of whom were members of the “Ratio Club” (1949– 1958).1 Not much of the communication between the two seems to have been preserved or discovered either, the major exception being a letter from Turing to Ashby that includes the following statement: In working on the ACE [an early digital computer] I am more interested in the possibility of producing models of the action of the brain than in the practical applications of computing.
    [Show full text]
  • The Cybernetic Brain
    THE CYBERNETIC BRAIN THE CYBERNETIC BRAIN SKETCHES OF ANOTHER FUTURE Andrew Pickering THE UNIVERSITY OF CHICAGO PRESS CHICAGO AND LONDON ANDREW PICKERING IS PROFESSOR OF SOCIOLOGY AND PHILOSOPHY AT THE UNIVERSITY OF EXETER. HIS BOOKS INCLUDE CONSTRUCTING QUARKS: A SO- CIOLOGICAL HISTORY OF PARTICLE PHYSICS, THE MANGLE OF PRACTICE: TIME, AGENCY, AND SCIENCE, AND SCIENCE AS PRACTICE AND CULTURE, A L L PUBLISHED BY THE UNIVERSITY OF CHICAGO PRESS, AND THE MANGLE IN PRAC- TICE: SCIENCE, SOCIETY, AND BECOMING (COEDITED WITH KEITH GUZIK). THE UNIVERSITY OF CHICAGO PRESS, CHICAGO 60637 THE UNIVERSITY OF CHICAGO PRESS, LTD., LONDON © 2010 BY THE UNIVERSITY OF CHICAGO ALL RIGHTS RESERVED. PUBLISHED 2010 PRINTED IN THE UNITED STATES OF AMERICA 19 18 17 16 15 14 13 12 11 10 1 2 3 4 5 ISBN-13: 978-0-226-66789-8 (CLOTH) ISBN-10: 0-226-66789-8 (CLOTH) Library of Congress Cataloging-in-Publication Data Pickering, Andrew. The cybernetic brain : sketches of another future / Andrew Pickering. p. cm. Includes bibliographical references and index. ISBN-13: 978-0-226-66789-8 (cloth : alk. paper) ISBN-10: 0-226-66789-8 (cloth : alk. paper) 1. Cybernetics. 2. Cybernetics—History. 3. Brain. 4. Self-organizing systems. I. Title. Q310.P53 2010 003’.5—dc22 2009023367 a THE PAPER USED IN THIS PUBLICATION MEETS THE MINIMUM REQUIREMENTS OF THE AMERICAN NATIONAL STANDARD FOR INFORMATION SCIENCES—PERMA- NENCE OF PAPER FOR PRINTED LIBRARY MATERIALS, ANSI Z39.48-1992. DEDICATION For Jane F. CONTENTS Acknowledgments / ix 1. The Adaptive Brain / 1 2. Ontological Theater / 17 PART 1: PSYCHIATRY TO CYBERNETICS 3.
    [Show full text]
  • Biological Homeostasis - Pietro Omodeo
    BIOLOGICAL SCIENCE FUNDAMENTALS AND SYSTEMATICS – Vol. I – Biological Homeostasis - Pietro Omodeo BIOLOGICAL HOMEOSTASIS Omodeo Pietro Department of Evolutionary Biology and Department of Environmental Sciences, University of Siena. Italy Keywords: Homeostasis, homeorrhesis, stabilisers, physiological control, control of stores, control of development, flux of genetic information. Contents 1. Introduction 2. Stabilization 3. Homeostasis 3.1. Logic and Structure of the Homeostat 3.2. The Components of the Homeostat: the Measuring Unit 3.3 The Components of the Homeostat: The Effector 3.4 The Control of Controllers 3.5. The Control of Stores 4. Homeorrhesis, the Automatic Control of Behavior 4.1. Trajectory Control 4.2. Smooth Control 4.3.Coordinate Control in Homeostasis and Homeorrhesis 5. Control of Development and Reproduction 5.1. Exogenous and Endogenous Clock and the Calendar 5.2. Embryonic Regulation 5.3. Control of the Flux of Genetic Information 6. Conclusion Acknowledgements Glossary Bibliography Biographical Sketch Summary HomeostasisUNESCO is a fundamental concept –in biology EOLSS because it helps to understand the aims of physiological functions and their behavior, and aids in explaining the mechanisms of regulation during ontogeny. Homeostasis is based on the principle of comparing the actualSAMPLE value of the parameters CHAPTERSunder control with an intended optimum. In case of discrepancy, the energetic or material input is regulated through a feedback loop conveying the error signal to the effectors. The effectors governing this input may have the nature of a switch or of a pump; in the latter case, the fatigue, or the défaillance, of the pump is controlled in its turn. This additional control is particularly important for the regulation of stores, because it primes a search program that directs motile organisms towards a food source that enables the restoration of optimum conditions.
    [Show full text]
  • How Cybernetics Connects Computing, Counterculture, and Design
    Walker Art Center — Hippie Modernism: The Struggle for Utopia — Exhibit Catalog — October 2015 How cybernetics connects computing, counterculture, and design Hugh Dubberly — Dubberly Design Office — [email protected] Paul Pangaro — College for Creative Studies — [email protected] “Man is always aiming to achieve some goal language, and sharing descriptions creates a society.[2] and he is always looking for new goals.” Suddenly, serious scientists were talking seriously —Gordon Pask[1] about subjectivity—about language, conversation, and ethics—and their relation to systems and to design. Serious scientists were collaborating to study Beginning in the decade before World War II and collaboration. accelerating through the war and after, scientists This turn away from the mainstream of science designed increasingly sophisticated mechanical and became a turn toward interdisciplinarity—and toward electrical systems that acted as if they had a purpose. counterculture. This work intersected other work on cognition in Two of these scientists, Heinz von Foerster and animals as well as early work on computing. What Gordon Pask, took an interest in design, even as design emerged was a new way of looking at systems—not just was absorbing the lessons of cybernetics. Another mechanical and electrical systems, but also biological member of the group, Gregory Bateson, caught the and social systems: a unifying theory of systems and attention of Stewart Brand, systems thinker, designer, their relation to their environment. This turn toward and publisher of the Whole Earth Catalog. Bateson “whole systems” and “systems thinking” became introduced Brand to von Foerster.[3] Brand’s Whole Earth known as cybernetics. Cybernetics frames the world in Catalog spawned a do-it-yourself publishing revolution, terms of systems and their goals.
    [Show full text]
  • Body Weight Homeostat That Regulates Fat Mass Independently of Leptin in Rats and Mice
    Body weight homeostat that regulates fat mass independently of leptin in rats and mice John-Olov Janssona,1, Vilborg Palsdottira, Daniel A. Häggb, Erik Schélea, Suzanne L. Dicksona, Fredrik Anestena, Tina Bakea, Mikael Monteliusc, Jakob Bellmana, Maria E. Johanssona, Roger D. Coned,e, Daniel J. Druckerf, Jianyao Wub, Biljana Aleksicb, Anna E. Törnqvistb, Klara Sjögrenb, Jan-Åke Gustafssong,1, Sara H. Windahlb, and Claes Ohlssonb,1 aDepartment of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, SE 405 30, Gothenburg, Sweden; bCentre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, SE 413 45, Gothenburg, Sweden; cDepartment of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE 413 45, Gothenburg, Sweden; dLife Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216; eDepartment of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-2216; fDepartment of Medicine, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, ON M5G 1X5, Toronto, Canada; and gDepartment of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX 77204 Contributed by Jan-Åke Gustafsson, November 8, 2017 (sent for review September 7, 2017; reviewed by Wolfgang Langhans and Subburaman Mohan) Subjects spending much time sitting have increased risk of obesity but and control rodents was first seen on day 2 after implantation the mechanism for the antiobesity effect of standing is unknown. We and was larger on day 14 when the experiment was terminated (Fig. hypothesized that there is a homeostatic regulation of body weight. 1 A and B).
    [Show full text]
  • CS765 Interactive Cognitive Systems
    CS765 Interactive Cognitive Systems L5: Cybernetics & Information Matthew Egbert Jim Warren What are some situated, embodied and dynamical - cybernetics approaches other than - enaction evolutionary robotics? Back in Lecture 3… Feedback The more XXXX there is, the more A number of approaches to XXXX there will be! understanding cognition have focused upon different types of feedback. Positive Feedback These tend to be more non-representationalist views that embrace aspects of situatedness, embodiment and dynamics. In particular, cybernetics (negative The more XXXX feedback as purposefulness) there is, the less XXXX there will be! Negative Feedback We tend to not be very good at thinking about systems that involve circular causality.. Is it possible for a passive vehicle on a flat surface to go directly downwind faster than the wind that is powering it? - wheeled vehicle - no motor - moving parts are allowed Back to by-hand engineering Instead of using EAs to design brains in SED robots, we can design controllers by hand. - Understandable - Test hypotheses - Understand implications of an architecture or assumptions - Demonstrate ideas - But perhaps hard to do? Can be representationalist or non-representationalist or perhaps even somewhere in between? The Homeostat "the closest thing to a synthetic brain so far designed by man". The Thinking Machine, Time, 24 January 1949. W. Ross Ashby W. Ross Ashby was a psychiatrist who (like many cyberneticists) did some of his most interesting work outside of his professional life (almost a hobby).[1] He wrote (very readable) books that had substantial (though not widely recognised) impact upon AI - Design for a Brain - Introduction to Cybernetics.
    [Show full text]
  • A Mobile Homeostat with Three Degrees of Freedom
    1 A Mobile Homeostat with Three Degrees of Freedom By Steve Battle Computer Science & Creative Technologies, University of the West of England, Bristol, UK Abstract In the foundational cybernetics text, Design for a Brain, W. Ross Ashby introduces an adaptive system called the homeostat, and speculates about the possibility of creating a mobile homeostat \with its critical states set so that it seeks situations of high illumina- tion." Simulations demonstrate the viability of using the classic homeostat architecture to control a mobile robot demonstrating ultrastability in adapting to an environment where the goal is to stay within range of a single source of illumination. This paper ex- plores a novel physical embodiment of Ashby's classic homeostat in a mobile robot with three degrees of freedom (2 translational, 1 rotational). The hypothesis, borne out by tests, is that the topological configuration of the robot as determined by simulation, will carry over into the physical robot. 1. Introduction Ashby's homeostat was described by Strehl (1955) as \the most remarkable and inexpli- cable machine which has yet been constructed." Completed in March 1948, the homeostat comprised four identical electro-mechanical, analogue computers identified by the colours red, green, blue and yellow. Ashby (1948) described his machine thus: each unit supports a suspended magnet with a read-out needle that could be deflected by currents in the four coils beneath it. These currents flow from the other three units and also within a feedback loop from each unit back to itself. The effect of one unit upon another can be individually configured.
    [Show full text]
  • N. Katherine Hayles
    Copyright © 1994 The Johns Hopkins University Press and the Society for Literature and Science. All rights reserved. Configurations 2.3 (1994) 441-467 Access provided by School of the Art Institute of Chicago Access provided by School of the Art Institute of Chicago Boundary Disputes: Homeostasis, Reflexivity, and the Foundations of Cybernetics N. Katherine Hayles Virtual reality did not spring, like Athena from the forehead of Zeus, full-blown from the mind of William Gibson. It has encoded within it a complex history of technological innovations, conceptual developments, and metaphorical linkages that are crucially important in determining how it will develop and what it is taken to signify. This essay explores that history by focusing on certain developments within cybernetics from the immediate post-World War II period to the present. These developments can be understood as progressing in three waves. The first period, 1945-1960, marks the foundational stage during which cybernetics was forged as an interdisciplinary framework that would allow humans, animals, and machines to be constituted through the common denominators of feedback loops, signal transmission, and goal-seeking behavior. The forum for these developments was a series of conferences sponsored by the Josiah Macy Foundation between 1946 and 1953. 1 Through the Macy discussions and the research presented there, the discipline solidified around key concepts and was disseminated into American intellectual communities by Macy [End Page 441] conferees, guests, and fellow travelers. Humans and machines had been equated for a long time, but it was largely through the Macy conferences that both were understood as information-processing systems.
    [Show full text]
  • The University of Okiahoma. Graduate College Digital
    THE UNIVERSITY OF OKIAHOMA. GRADUATE COLLEGE DIGITAL SIMULATION OF THE HOMEOSTAT MODIFIED TO SHOW MEMORY AND LEARNING A DISSERTATION SUBMITTED TO THE GRADUATE FACULTY in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY by BARNEY LEE CAPEHART Norman, Oklahoma 1967 DIGITAL SIMULATION OF THE HOMEOSTAT MODIFIED TO SHOW MEMORY AND LEARNING APPROVED BY r y ^ A ' X'Ct DISSERTATION COMMITTEE ACKNOWLEDGEMENTS The author wishes to acknowledge his indebtedness to Dr. Richard A. Terry whose guidance, patience and under­ standing made possible the success of this investigation, and also to all members of the author's advisory committee. XXI TABLE OF CONTENTS Page LIST OF TABLES ..... ............................. v LIST OF ILLUSTRATIONS ............................... vi Chapter I. INTRODUCTION ................................. 1 II. THE ULTRASTABLE S Y S T E M .......... k III. THE H O M E O S T A T ................................. l6 IV. A FORTRAN PROGRAM FOR SIMULATING THE HOMEOSTAT ................................... 21 V. EXAMPLES OF HOMEOSTAT BEHAVIOR ............. 29 VI. DEVELOPMENT OF MEMORY AND LEARNING FOR THE HOMEOSTAT .......................... 4l VII. FINAL EXAMPLE AND CONCLUSIONS ........ 65 REFERENCES ............................................ ?6 Appendices A. FLOW CHART AND LISTING OF THE COMPUTER PROGRAM TO SIMULATE THE BASIC HOMEOSTAT . 79 B. LISTING OF FORTRAN SUBROUTINES USED BY ALL PROGRAMS SIMULATING THE HOMEOSTAT ........ 88 C. LISTING OF THE COMPUTER PROGRAM TO SIMULATE THE HOMEOSTAT WITH INPUT PATTERN RECOGNI­ TION CAPABILITY . ........................ 92 D. FLOW CHART AND LISTING OF THE COMPUTER PROGRAM TO SIMULATE THE HOMEOSTAT WITH MEMORY AND LEARNING ........................... 100 XV LIST OF TABLES Table Page 1. A Comparison of Adaptation Times as the Number of Variables is Increased ........... 37 2. Results of Runs Where the A Matrix is Allowed to have Randomly Signed Main Diagonal Terms ..............................
    [Show full text]
  • The Philosophy of W. Ross Ashby 149 Peter M
    The Mechanical Mind in History edited by Philip Husbands, Owen Holland, and Michael Wheeler A Bradford Book The MIT Press Cambridgg Massachusetts London, England Contents Preface vii I Introduction: The Mechanical Mind 1 Philip Husbands, Michael Wheeler, and Owen Holland 2 Charles Babbage and the Emergence of Automated Reason 19 Seth Bullock 3 D'Arcy Thompson: A Grandfather of A-Life 41 Margaret A. Boden 4 Alan Turing's Mind Machines 6"1 Donald Michie 5 What Did Alan Turing Mean by "Machine"? 75 Andrew Hodges 6 The Ratio Club: A Hub of British Cybernetics 91 Philip Husbands and Owen Holland 7 From Mechanisms of Adaptation to lntelligence Amplifiers: The Philosophy of W. Ross Ashby 149 Peter M. Asaro 8 Gordon Pask and His Maverick Machines 185 Jon Bird and Ezequiei Di Paolo 9 Santiago Dreaming 213 Andy Beckett 10 Steps Toward the Synthetic Method: Symbolic Information Processing and Self-Organizing Systems in Early Artificial Intelligence Modeling 21g Roberto Cordeschi 7 From Mechanisms of Adaptation to Intelligence Amplifiers: The Philosophy of W. Ross Ashby Peter M. Asaro During the last few years it has become apparent that the concept of ‘‘machine’’ must be very greatly extended if it is to include the most modern developments. Es- pecially is this true if we are studying the brain and attempting to identify the type of mechanism that is responsible for the brain’s outstanding powers of thought and action. It has become apparent that when we used to doubt whether the brain could be a machine, our doubts were due chiefly to the fact that by ‘‘machine’’ we under- stood some mechanism of very simple type.
    [Show full text]
  • Contribution of the Circadian Pacemaker and the Sleep
    The Journal of Neuroscience, May 1995, 15(5): 3526-3538 Contribution of the Circadian Pacemaker and the Sleep Homeostat to Sleep Propensity, Sleep Structure, Electroencephalographic Slow Waves, and Sleep Spindle Activity in Humans Derk-Jan Dijk and Charles A. Czeisler Section on Sleep Disorders/Circadian Medicine, Division of Endocrinology, Department of Medicine, Harvard Medical School and Brigham and Women’s Hospital, Boston, Massachusetts 02115 The role of the endogenous circadian pacemaker in the tim- The suprachiasmatic nuclei (SCN) of the hypothalamus are the ing of the sleep-wake cycle and the regulation of the in- locus of an endogenous self-sustaining circadian pacemaker ternal structure of sleep, including REM sleep, EEG slow- (Moore and Eichler, 1972; Stephan and Zucker, 1972; for re- wave (0.7545 Hz) and sleep spindle activity (12.75-15.0 views, see Rusak and Zucker, 1979; Meijer and Rietveld, 1989; Hz) was investigated. Eight men lived in an environment Klein et al., 1991) regulating circadian rhythms of a variety of free of time cues for 33-36 d and were scheduled to a 28 physiological variables including plasma melatonin (Moore and hr rest-activity cycle so that sleep episodes (9.33 hr each) Klein, 1974), plasma corticosterone (Moore and Eichler, 1972) occurred at all phases of the endogenous circadian cycle and core body temperature (Eastman et al., 1984; Edgar, 1986). and variations in wakefulness preceding sleep were mini- The SCN are also involved in the timing of sleep and wakeful- mized. The crest of the robust circadian rhythm of REM ness, as has been demonstrated by lesion studies in both rodents sleep, which was observed throughout the sleep episode, (Mistlberger et al., 1983; Tobler et al., 1983; Eastman et al., was positioned shortly after the minimum of the core body 1984; Trachsel et al., 1992) and the squirrel monkey (Edgar, temperature rhythm.
    [Show full text]