44,216 research outputs found
Genetic Algorithm for Epidemic Mitigation by Removing Relationships
Min-SEIS-Cluster is an optimization problem which aims at minimizing the
infection spreading in networks. In this problem, nodes can be susceptible to
an infection, exposed to an infection, or infectious. One of the main features
of this problem is the fact that nodes have different dynamics when interacting
with other nodes from the same community. Thus, the problem is characterized by
distinct probabilities of infecting nodes from both the same and from different
communities. This paper presents a new genetic algorithm that solves the
Min-SEIS-Cluster problem. This genetic algorithm surpassed the current
heuristic of this problem significantly, reducing the number of infected nodes
during the simulation of the epidemics. The results therefore suggest that our
new genetic algorithm is the state-of-the-art heuristic to solve this problem.Comment: GECCO '17 - Proceedings of the Genetic and Evolutionary Computation
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Neural Dynamics of Autistic Behaviors: Cognitive, Emotional, and Timing Substrates
What brain mechanisms underlie autism and how do they give rise to autistic behavioral symptoms? This article describes a neural model, called the iSTART model, which proposes how cognitive, emotional, timing, and motor processes may interact together to create and perpetuate autistic symptoms. These model processes were originally developed to explain data concerning how the brain controls normal behaviors. The iSTART model shows how autistic behavioral symptoms may arise from prescribed breakdowns in these brain processes.Air Force Office of Scientific Research (F49620-01-1-0397); Office of Naval Research (N00014-01-1-0624
Embodied Evolution in Collective Robotics: A Review
This paper provides an overview of evolutionary robotics techniques applied
to on-line distributed evolution for robot collectives -- namely, embodied
evolution. It provides a definition of embodied evolution as well as a thorough
description of the underlying concepts and mechanisms. The paper also presents
a comprehensive summary of research published in the field since its inception
(1999-2017), providing various perspectives to identify the major trends. In
particular, we identify a shift from considering embodied evolution as a
parallel search method within small robot collectives (fewer than 10 robots) to
embodied evolution as an on-line distributed learning method for designing
collective behaviours in swarm-like collectives. The paper concludes with a
discussion of applications and open questions, providing a milestone for past
and an inspiration for future research.Comment: 23 pages, 1 figure, 1 tabl
Dynamically optimal treatment allocation using Reinforcement Learning
Devising guidance on how to assign individuals to treatment is an important
goal in empirical research. In practice, individuals often arrive sequentially,
and the planner faces various constraints such as limited budget/capacity, or
borrowing constraints, or the need to place people in a queue. For instance, a
governmental body may receive a budget outlay at the beginning of a year, and
it may need to decide how best to allocate resources within the year to
individuals who arrive sequentially. In this and other examples involving
inter-temporal trade-offs, previous work on devising optimal policy rules in a
static context is either not applicable, or sub-optimal. Here we show how one
can use offline observational data to estimate an optimal policy rule that
maximizes expected welfare in this dynamic context. We allow the class of
policy rules to be restricted for legal, ethical or incentive compatibility
reasons. The problem is equivalent to one of optimal control under a
constrained policy class, and we exploit recent developments in Reinforcement
Learning (RL) to propose an algorithm to solve this. The algorithm is easily
implementable with speedups achieved through multiple RL agents learning in
parallel processes. We also characterize the statistical regret from using our
estimated policy rule by casting the evolution of the value function under each
policy in a Partial Differential Equation (PDE) form and using the theory of
viscosity solutions to PDEs. We find that the policy regret decays at a
rate in most examples; this is the same rate as in the static case.Comment: 67 page
Agent-Based Models and Human Subject Experiments
This paper considers the relationship between agent-based modeling and economic decision-making experiments with human subjects. Both approaches exploit controlled ``laboratory'' conditions as a means of isolating the sources of aggregate phenomena. Research findings from laboratory studies of human subject behavior have inspired studies using artificial agents in ``computational laboratories'' and vice versa. In certain cases, both methods have been used to examine the same phenomenon. The focus of this paper is on the empirical validity of agent-based modeling approaches in terms of explaining data from human subject experiments. We also point out synergies between the two methodologies that have been exploited as well as promising new possibilities.agent-based models, human subject experiments, zero- intelligence agents, learning, evolutionary algorithms
Spatio-Temporal Patterns act as Computational Mechanisms governing Emergent behavior in Robotic Swarms
open access articleOur goal is to control a robotic swarm without removing its swarm-like nature. In other words, we aim to intrinsically control a robotic swarm emergent behavior. Past attempts at governing robotic swarms or their selfcoordinating emergent behavior, has proven ineffective, largely due to the swarm’s inherent randomness (making it difficult to predict) and utter simplicity (they lack a leader, any kind of centralized control, long-range communication, global knowledge, complex internal models and only operate on a couple of basic, reactive rules). The main problem is that emergent phenomena itself is not fully understood, despite being at the forefront of current research. Research into 1D and 2D Cellular Automata has uncovered a hidden computational layer which bridges the micromacro gap (i.e., how individual behaviors at the micro-level influence the global behaviors on the macro-level). We hypothesize that there also lie embedded computational mechanisms at the heart of a robotic swarm’s emergent behavior. To test this theory, we proceeded to simulate robotic swarms (represented as both particles and dynamic networks) and then designed local rules to induce various types of intelligent, emergent behaviors (as well as designing genetic algorithms to evolve robotic swarms with emergent behaviors). Finally, we analysed these robotic swarms and successfully confirmed our hypothesis; analyzing their developments and interactions over time revealed various forms of embedded spatiotemporal patterns which store, propagate and parallel process information across the swarm according to some internal, collision-based logic (solving the mystery of how simple robots are able to self-coordinate and allow global behaviors to emerge across the swarm)
From Social Simulation to Integrative System Design
As the recent financial crisis showed, today there is a strong need to gain
"ecological perspective" of all relevant interactions in
socio-economic-techno-environmental systems. For this, we suggested to set-up a
network of Centers for integrative systems design, which shall be able to run
all potentially relevant scenarios, identify causality chains, explore feedback
and cascading effects for a number of model variants, and determine the
reliability of their implications (given the validity of the underlying
models). They will be able to detect possible negative side effect of policy
decisions, before they occur. The Centers belonging to this network of
Integrative Systems Design Centers would be focused on a particular field, but
they would be part of an attempt to eventually cover all relevant areas of
society and economy and integrate them within a "Living Earth Simulator". The
results of all research activities of such Centers would be turned into
informative input for political Decision Arenas. For example, Crisis
Observatories (for financial instabilities, shortages of resources,
environmental change, conflict, spreading of diseases, etc.) would be connected
with such Decision Arenas for the purpose of visualization, in order to make
complex interdependencies understandable to scientists, decision-makers, and
the general public.Comment: 34 pages, Visioneer White Paper, see http://www.visioneer.ethz.c
Guns, germs, and stealing: exploring the link between infectious disease and crime.
Can variation in crime rates be traced to the threat of infectious disease? Pathogens pose an ongoing challenge to survival, leading humans to adapt defenses to manage this threat. In addition to the biological immune system, humans have psychological and behavioral responses designed to protect against disease. Under persistent disease threat, xenophobia increases and people constrict social interactions to known in-group members. Though these responses reduce disease transmission, they can generate favorable crime conditions in two ways. First, xenophobia reduces inhibitions against harming and exploiting out-group members. Second, segregation into in-group factions erodes people's concern for the welfare of their community and weakens the collective ability to prevent crime. The present study examined the effects of infection incidence on crime rates across the United States. Infection rates predicted violent and property crime more strongly than other crime covariates. Infections also predicted homicides against strangers but not family or acquaintances, supporting the hypothesis that in-group-out-group discrimination was responsible for the infections-crime link. Overall, the results add to evidence that disease threat shapes interpersonal behavior and structural characteristics of groups
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