23,662 research outputs found
Discrete and fuzzy dynamical genetic programming in the XCSF learning classifier system
A number of representation schemes have been presented for use within
learning classifier systems, ranging from binary encodings to neural networks.
This paper presents results from an investigation into using discrete and fuzzy
dynamical system representations within the XCSF learning classifier system. In
particular, asynchronous random Boolean networks are used to represent the
traditional condition-action production system rules in the discrete case and
asynchronous fuzzy logic networks in the continuous-valued case. It is shown
possible to use self-adaptive, open-ended evolution to design an ensemble of
such dynamical systems within XCSF to solve a number of well-known test
problems
Techniques for the Synthesis of Reversible Toffoli Networks
This paper presents novel techniques for the synthesis of reversible networks
of Toffoli gates, as well as improvements to previous methods. Gate count and
technology oriented cost metrics are used. Our synthesis techniques are
independent of the cost metrics. Two new iterative synthesis procedure
employing Reed-Muller spectra are introduced and shown to complement earlier
synthesis approaches. The template simplification suggested in earlier work is
enhanced through introduction of a faster and more efficient template
application algorithm, updated (shorter) classification of the templates, and
presentation of the new templates of sizes 7 and 9. A novel ``resynthesis''
approach is introduced wherein a sequence of gates is chosen from a network,
and the reversible specification it realizes is resynthesized as an independent
problem in hopes of reducing the network cost. Empirical results are presented
to show that the methods are effective both in terms of the realization of all
3x3 reversible functions and larger reversible benchmark specifications.Comment: 20 pages, 5 figure
Entropy of complex relevant components of Boolean networks
Boolean network models of strongly connected modules are capable of capturing
the high regulatory complexity of many biological gene regulatory circuits. We
study numerically the previously introduced basin entropy, a parameter for the
dynamical uncertainty or information storage capacity of a network as well as
the average transient time in random relevant components as a function of their
connectivity. We also demonstrate that basin entropy can be estimated from
time-series data and is therefore also applicable to non-deterministic networks
models.Comment: 8 pages, 6 figure
Optimal percentage of inhibitory synapses in multi-task learning
Performing more tasks in parallel is a typical feature of complex brains.
These are characterized by the coexistence of excitatory and inhibitory
synapses, whose percentage in mammals is measured to have a typical value of
20-30\%. Here we investigate parallel learning of more Boolean rules in
neuronal networks. We find that multi-task learning results from the
alternation of learning and forgetting of the individual rules. Interestingly,
a fraction of 30\% inhibitory synapses optimizes the overall performance,
carving a complex backbone supporting information transmission with a minimal
shortest path length. We show that 30\% inhibitory synapses is the percentage
maximizing the learning performance since it guarantees, at the same time, the
network excitability necessary to express the response and the variability
required to confine the employment of resources.Comment: 5 pages, 5 figure
Emergence of Complex Dynamics in a Simple Model of Signaling Networks
A variety of physical, social and biological systems generate complex
fluctuations with correlations across multiple time scales. In physiologic
systems, these long-range correlations are altered with disease and aging. Such
correlated fluctuations in living systems have been attributed to the
interaction of multiple control systems; however, the mechanisms underlying
this behavior remain unknown. Here, we show that a number of distinct classes
of dynamical behaviors, including correlated fluctuations characterized by
-scaling of their power spectra, can emerge in networks of simple
signaling units. We find that under general conditions, complex dynamics can be
generated by systems fulfilling two requirements: i) a ``small-world'' topology
and ii) the presence of noise. Our findings support two notable conclusions:
first, complex physiologic-like signals can be modeled with a minimal set of
components; and second, systems fulfilling conditions (i) and (ii) are robust
to some degree of degradation, i.e., they will still be able to generate
-dynamics
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