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Full-Text Articles in Physical Sciences and Mathematics

Random Automata Networks: Why Playing Dice Is Not A Vice, Christof Teuscher Dec 2010

Random Automata Networks: Why Playing Dice Is Not A Vice, Christof Teuscher

Systems Science Friday Noon Seminar Series

Random automata networks consist of a set of simple compute nodes interacting with each other. In this generic model, one or multiple model parameters, such as the the node interactions and/or the compute functions, are chosen at random. Random Boolean Networks (RBNs) are a particular case of discrete dynamical automata networks where both time and states are discrete. While traditional RBNs are generally credited to Stuart Kauffman (1969), who introduced them as simplified models of gene regulation, Alan Turing proposed unorganized machines as early as 1948. In this talk I will start with Alan Turing's early work on unorganized machines, …


Understanding, Modeling And Valuing Ecosystem Services, Robert Costanza Oct 2010

Understanding, Modeling And Valuing Ecosystem Services, Robert Costanza

Systems Science Friday Noon Seminar Series

Ecosystem services (ES) are the direct and indirect contributions of ecosystems (in combination with other inputs) to human well-being. An ES-based approach can assess the trade-offs inherent in managing humans embedded in ecological systems. Evaluating trade-offs requires both an understanding of the biophysical magnitudes of ES changes that result from human actions, as well as an understanding of their impact on human well-being, broadly conceived. This talk discusses the state of the art of ES assessment, valuation, and modeling, including the potential of integrated ecological economic modeling. Valuation is about assessing trade-offs – not necessarily about trades (exchanges) in markets …


The Hydro-Ecology Of Everyday Life: Assessing The Social And Environmental Determinants Of Water Use In The Portland Region, Vivek Shandas May 2010

The Hydro-Ecology Of Everyday Life: Assessing The Social And Environmental Determinants Of Water Use In The Portland Region, Vivek Shandas

Systems Science Friday Noon Seminar Series

Driven in part by the imminent threats of population growth and climate destabilization, recent studies suggest that urban areas face severe water scarcity, with some areas in Australia and the United States already instituting moratoria on water use. While water managers traditionally avoid such crises by developing demand forecasts based on population estimates, technological developments, and weather predictions, their analysis are often at a regional scale with aggregate measures of water consumption. To date, there exists limited empirical evidence about how urban spatial structure and concomitant socio-demographic and temperature characteristics mutually interact to affect water demand at the scale of …


Reconstructability Analysis Of Elementary Cellular Automata, Martin Zwick, Hui Shi Mar 2010

Reconstructability Analysis Of Elementary Cellular Automata, Martin Zwick, Hui Shi

Systems Science Friday Noon Seminar Series

Reconstructability analysis is a method to determine whether a multivariate relation, defined set- or information-theoretically, is decomposable with or without loss (reduction in constraint) into lower ordinality relations. Set-theoretic reconstructability analysis (SRA) is used to characterize the mappings of elementary cellular automata. The degree of lossless decomposition possible for each mapping is more effective than the λ parameter (Walker & Ashby, Langton) as a predictor of chaotic dynamics.

Complete SRA yields not only the simplest lossless structure but also a vector of losses of all decomposed structures, indexed by parameter, τ. This vector subsumes λ, Wuensche’s Z parameter, and Walker …


Biologically Inspired Computing: The Darpa Synapse Program & The Hierarchical Temporal Memory, Dan Hammerstrom Feb 2010

Biologically Inspired Computing: The Darpa Synapse Program & The Hierarchical Temporal Memory, Dan Hammerstrom

Systems Science Friday Noon Seminar Series

This presentation provides an update on biologically inspired computation. In particular, it focuses on two important developments in this area, the DARPA SyNAPSE program (Systems of Neuromorphic Adaptive Plastic Scalable Electronics) and the HTM (Hierarchical Temporal Memory) being developed by Numenta.

The SyNAPSE Program’s ultimate goal is to build a low-power, compact electronic chip combining novel analog circuit design and a neuroscience-inspired architecture that can address a wide range of cognitive abilities: perception, planning, decision making and motor control. According to DARPA program manager Todd Hylton, “Our research progress in this area is unprecedented, No suitable electronic synaptic device that …


Understanding Classification Decisions For Object Detection, Will Landecker, Michael David Thomure, Melanie Mitchell Feb 2010

Understanding Classification Decisions For Object Detection, Will Landecker, Michael David Thomure, Melanie Mitchell

Systems Science Friday Noon Seminar Series

Computer vision systems are traditionally tested in the object detection paradigm. In these experiments, a vision system is asked whether or not a specific object--for example an animal--occurs in a given image. A system that often answers correctly is said to be very accurate. In this talk, we will discuss some ambiguity that exists in this measure of accuracy. We will also propose a new measure of object-detection accuracy that addresses some of this ambiguity, and apply this measure to the hierarchical "standard model" of visual cortex.