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Topic: Tierra (computer simulation)

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Tom Ray

Artificial life

	Tierra (computer simulation) - Wikipedia, the free encyclopedia
		Tierra is a computer simulation developed by ecologist Thomas S. Ray in the early 1990s in which computer programs compete for central processor unit (CPU) time and access to main memory.
		Tierra is a frequently cited example of an artificial life model; in the metaphor of the Tierra, the evolvable computer programs can be considered as digital organisms which compete for energy (CPU time) and resources (main memory).
		Tierra is an abstract model, but any quantitative model is still subject to the same validation and verification techniques applied to more traditional mathematical models, and as such, has no special status.
	en.wikipedia.org /wiki/Tierra_(computer_simulation) (369 words)

	Modeling and Simulation (Site not responding. Last check: 2007-10-08)
		System Simulation is the mimicking of the operation of a real system, such as the day-to-day operation of a bank, or the value of a stock portfolio over a time period, or the running of an assembly line in a factory, or the staff assignment of a hospital or a security company, in a computer.
		A flight simulator on a PC is also a computer model of some aspects of the flight: it shows on the screen the controls and what the "pilot" (the youngster who operates it) is supposed to see from the "cockpit" (his armchair).
		Another strategy for estimating the gradient simulation is based on the frequency domain method, which differs from the time domain experiments in that the input parameters are deterministically varied in sinusoidal patterns during the simulation run, as opposed to being kept fixed as in the time domain runs.
	www.cs.sun.ac.za /~lynette/simulation/harsham/sim.html (13045 words)

	John L. Casti: Would-Be Worlds
		The main argument of the book is that computer simulation modelling represents a major scientific advance because it allows us to study the mechanisms of complex systems: systems that arise from the interaction of their parts.
		Although not his intent, this exemplifies how results from computer simulations can be misleading when not enough consideration is given to the mechanisms that operate in the real world.
		He states, "As with all computer exercises, it's garbage-in, garbage-out, and the faith we place in the model's answers is inversely proportional to the amount of garbage that goes in." (p.
	jasss.soc.surrey.ac.uk /4/1/reviews/andersen.html (1491 words)

	Artificial Life
		Individual-based models are simulations based on the global consequences of local interactions of members of a population.
		This SIG is intended to reinforce the development of a strong European presence in social simulation and also to demonstrate that the disciplines on which the social simulation community draws can themselves benefit from the results obtained by members of that community.
		The simulation studies the behavior of a large pool of agents who listen to messages on what is popular.
	www.insead.fr /CALT/Encyclopedia/ComputerSciences/AI/aLife.htm (4118 words)

	[No title]
		As in all of the computer models examined by Casti, he show restraint by not declaring that the science is a monstrous breakthrough that will change the world; He avoids a position that many early artificial intelligence researchers fell into--making broad, overstated predictions of its use.
		The computer used a set of rules that generated images, but that does not mean the same rules were followed by nature in creating real flowers.
		Tierra uses the same structure of so called digital life of a computer that goes through a process whereby programs are allocated time and memory to operate.
	www.gslis.utexas.edu /~palmquis/courses/reviews/dbaker.htm (1116 words)

	No Title
		This experiment allowed a computer to monitor Kevin Warwick as he moved through halls and offices of the Department of Cybernetics at the University of Reading, using a unique identifying signal emitted by the implanted chip.
		We are already at a stage where we trust computers enough to build them with a drive, comparable to an instinct, that constantly stimulates them to search for conclusions and to then create tools to follow these conclusions.
		What it leads to is that computers do no longer follow the in-programmed formulas in order to find a solution, but find their own ways of solving a given problem.
	www.logic.at /lvas/185170/04-Pevzner.html (3727 words)

	Dissertations, GA Archives (Site not responding. Last check: 2007-10-08)
		Simulation results proved that Symbiotic Evolution, coupled with fuzzy logic to form a hybrid structure can be very successful in the design of an efficient active suspension system in terms of performance and size of the fuzzy rule-base.
		It has been widely recognised in the computational intelligence and machine learning communities that the key to understanding the behaviour of learning algorithms is to understand what representation is employed to capture and manipulate knowledge acquired during the learning process.
		In this dissertation we present the multi-niche crowding genetic algorithm, a computational metaphor to the survival of species in ecological niches in the face of competition.
	www.aic.nrl.navy.mil /galist/dissert.html (6910 words)

	Michael Drennan: The Human Science of Simulation
		Any substantial exploration of simulation results would be seen to proceed not from a continuing theoretical discourse grounded in valid findings, but from the cultural preconceptions under girding the simulation.
		By recounting verbatim the harsh critique of his work delivered by Tom Ray, inventor of the Tierra simulation, Helmreich reflects on a crucial weakness of cultural studiesÄö the loss of the historical individual to their cultural contexts (1998: 240).
		Far from limiting the descriptive power of simulations, their ability to visualize what could be, the contextualization and reflexive negotiation of their construction would make such artificial societies intelligible even to those of a pure interpretive vein.
	jasss.soc.surrey.ac.uk /8/1/3.html (7669 words)

	Digital Organism...Artilifes.com
		It turned out that one of the winning strategies was to replicate as fast as possible, which had the result that the opponent was deprived of all computational resources.
		In Tierra, all programs were living in the same address space, and could potentially overwrite or otherwise interfere with each other.
		The main difference between Avida and Tierra is that in Avida, every digital organism (that is, self-replicating computer program) lives in its own protected region of memory, and is executed by its own virtual CPU.
	www.artilifes.com /digitalorganism.html (856 words)

	Overview of simulation tools
		Tierra and Avida are suitable for experiments focused on the study of artificial organisms at the level of their genomes.
		Tierra does not allow interactive watching and analyzing the simulation and the work with the system means a lot of raw data handling.
		The main entity in simulation is an agent that can represent an organism in ecosystem simulation, an enterprise in economical model or a molecule in an artificial chemistry system, for example.
	neuron-ai.tuke.sk /~zvirinsk/thesis/node5.html (938 words)

	Evolving Parallel Computation
		Although the digital computer is a very different environment than the ecology of the Earth, evolution is shown to work effectively in the digital environment and produce significant increases in parallelism.
		The Tierra computer has a small but otherwise fairly normal instruction set, which is Turing complete and capable of general purpose computation [5].
		In nearly all of the multi-cellular Tierra simulations that were run, two distinct evolutionary phases can be observed after the initial population develops.
	www.thearling.com /text/evpar/evpar.htm (2672 words)

	Tierra Verde Resort (Site not responding. Last check: 2007-10-08)
		Tierra is the name of various distinct things:
		Tierra, a computer simulation of life bythe ecologist Thomas S. Ray.
		Tierra Entertainment, now known as AGD Interactive, is anon-profit game company specializing in remakes of classic adventuregames by Sierra Entertainment.
	www.witchware.com /File/45898-Tierra.Verde.Resort.Html (313 words)

	LiNUX.COM - Linux Ecology HOWTO: Ecology Software (Simulation, Datacollection, Statistics, etc.)
		Tierra is a tool for studying digital evolution and ecology that runs on Linux and other OSes.
		SWARM is a software package for multi-agent simulation of complex systems that is being developed by the Swarm Development Group (SDG).
		Climate-Dynamics is project to share computer client resources to analyze the climate.
	www.linux.com /howtos/Ecology-HOWTO-13.shtml (616 words)

	TIERRA
		A DOS version of the Tierra software with a decent frontend will be ready for sale ($70) by November.
		Synthetic organisms have been created based on a computer metaphor of organic life in which CPU time is the ``energy'' resource and memory is the ``material'' resource.
		The only genetic change imposed on the simulator is random bit flips in the machine code of the creatures.
	www.talkorigins.org /faqs/tierra.html (1554 words)

	FAQ: comp.ai.genetic part 3/6 (A Guide to Frequently Asked Questions)
		There exist deterministic algorithms that given a set of constraints (rules), compute the more stable structure, but: (a) their time and memory requirement increase quadratically or more with the length of the sequences, and (b) they require simplified rules.
		Tierra Synthetic organisms have been created based on a computer metaphor of organic life in which CPU time is the ``energy'' resource and memory is the ``material'' resource.
		Since computer programs are just patterns of information, a successful program in core wars is one that replicates its pattern within the memory, so that eventually most of the memory contains its pattern rather than that of the competing program.
	www.faqs.org /faqs/ai-faq/genetic/part3 (6295 words)

	Nerve Garden Paper
		Today's computer viruses, which some claim is a form of digital proto-life, trace their origins to Conway's game of Life and back even further to Von Neumann's concept of automata.
		Each Tierra virtual machine is a memory space filled by strings representing genomes, which seek to copy themselves, mutating in the process.
		Tierra was brought to the Internet and to VRML when Dr. Ray distributed Tierra to run in as a distributed background process on thousands of machines, creating a "digital preserve".
	www.digitalspace.com /papers/bruce_damer.htm (2882 words)

	Amazon.com: Silicon Second Nature : Culturing Artificial Life in a Digital World: Books: Stefan Helmreich (Site not responding. Last check: 2007-10-08)
		Indeed, his descriptions of the theories and techniques behind some researchers' attempts at concocting artificial life--ranging from simple computer viruses to Tom Ray's globally distributed Tierra system for breeding digital "organisms"--are occasionally more compelling than his own attempts to read disturbing racial and sexual mythologies into those experiments.
		Computational studies in evolution are at bottom a matter of binary code.
		Now, clearly the researcher at their computer may indeed be any of the above--but that does not change the code itself.
	www.amazon.com /exec/obidos/tg/detail/-/0520207998?v=glance (1887 words)

	Middle Earth From Space
		These views of middle earth were simulated using pieces of imagery of Earth's topography as viewed from space and freely available from NASA's VISIBLE EARTH web site.
		The cloud Map was adapted from the map from http://members.shaw.ca/ evildrganymede/art/planets/earth.htm The idea to create these views was inspired on the JRR Tolkien's Lord of the Rings books.
		The space simulator ORBITER, written and maintained by Martin Schweiger.
	www.sandinovive.org /webusers/guests/e_worlds/mdlearth_from_space.htm (344 words)

	SPACE.com -- Researchers Say Asteroid Impact Could Alter Climate
		Fawcett said similarities between the computer simulation and the Eocene cold spell are not proof of anything, but the similarities suggest a ringworld is worth considering.
		He had worked with Fawcett to modify climate simulation computer programs to run on Sandia's supercomputers, so using those programs to test the ring hypothesis seemed logical.
		He turned the results over to Fawcett, who uses computer simulations and field studies to try to understand changes in the climate of ancient Earth.
	www.space.com /scienceastronomy/planetearth/asteroid_impact_020626.html (526 words)

	CVC News (Site not responding. Last check: 2007-10-08)
		The National Science Foundation has granted $1.1 million to a collaboration of medical and engineering researchers at UT Austin to use computer modeling for controlling a heat-based treatment for prostate cancer.
		Tinsley Oden, professor of aerospace engineering and engineering mechanics and director of the Institute for Computational Engineering and Sciences, is the principal investigator of the team involving colleagues in the College of Engineering and at M.D. Anderson Cancer Center in Houston.
		Chandrajit Bajaj, who holds the ICES Chair in Computational Visualization, also is a co-investigator on the project.
	ccvweb.csres.utexas.edu /ccv/news.php (722 words)

	ERCB: Would-Be Worlds
		Would-Be Worlds is a brief, non-technical survey of the state of the art in computer simulation and modeling, ranging from weather to political insurgencies, from freeway traffic to the stock market.
		Although he starts out the book with a rather good example of simulation (including its limitations) -- a computer-based football game -- Casti occasionally gets carried away with enthusiasm and loses sight of the essential (and crucial) differences between simulation and the Ding an sich.
		Engineers and software developers looking for an overview of simulation will be disappointed in the degree of sophistication and insight that is presented here.
	www.ercb.com /brief/brief.0029.html.backup (246 words)

	Hayabusa: JAXA Delays Departure of Injured “Falcon” to 2007 - Planetary News \| The Planetary Society
		In this state, Hayabusa’s communication computer enters stand-by mode by shutting down the power, Kawaguchi explained.
		The figures I put before does not mean that it can return to the Earth with a ‘70% probability.’ It means that ‘for the 70% probability of communication recovery, we will continue the operation,’" he clarified.
		Computer simulation of Hayabusa sampling the surface of Itokawa Credit: Kazuya Yoshida, Space Robotics Laboratory, Tohoku University
	planetary.org /news/2005/1214_Hayabusa_JAXA_Delays_Departure_of.html (2475 words)

	RESULTS
		, the evolutionary process was simulated by a simple computer program, ev, for which I will describe one evolutionary run.
		Given that gene duplication is common and that transcription and translation are part of the housekeeping functions of all cells, the program simulates the process of evolution of new binding sites from scratch.
		Because a computer simulation does not correlate with time, the haldane and darwin can be combined to give units of bits per generation, in this case
	www.lecb.ncifcrf.gov /~toms/paper/ev/latex/node4.html (1273 words)

	[No title] (Site not responding. Last check: 2007-10-08)
		Simulation and Modelling/Nikola Guid/University of Maribor - Croatia
		Computer Simulation/John Najarian/William Paterson University of New Jersey,
		Computer Simulation with Mathematica (explorations in complex, physical, and biological systems)
	www.sosresearch.org /simulationeducation/simsoftware.html (2655 words)

	[No title] (Site not responding. Last check: 2007-10-08)
		Ray began studying model ecosystems in which the organisms are self-reproducing computer programs that live and spawnwithin the confined world of a computer's memory core.
		Organisms emerged acting as parasites, borrowing the instructions of their hosts to replicate themselves and hosts respond by forming boundaries to ward off the parasites.
		A plot of the size distribution of extinction events in Tierra was performed to look for a typical power law signature, indicative of complex systems.
	park.org /Canada/Museum/complexity/complex8.html (125 words)

	[No title]
		Prior to the domestication of various food crops and the transition to sedentary, agricultural societies, a process that began in many areas between 7000-5000 BC, human inhabitants of the Americas lived in small groups, migrating periodically in search of game and wild plant materials.
		At the end of the fifteenth century, the Arctic and Subarctic regions of Canada and Alaska, the Great Basin and southwestern areas of the United States, northern Mexico, the Amazon Basin, Patagonia, and Tierra del Fuego in southern South America all continued to support small hunter-gatherer populations.
		McGrath, J.W. 1986 "A computer simulation of the spread of tuberculosis in prehistoric populations of the Lower Illinois River valley." Ph.D. dissertation, Northwestern University.
	www.hist.umn.edu /~rmccaa/laphb/27fall97/laphb27a.htm (7278 words)

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