SANS annual report 1994

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ANS simulator

ANS simulator

By: Anders Lansner

Within this project we have developed an ANS simulator ("ANSim") which is "all-neural" i.e. with adapting units, print-now signals, gating of connections etc. in addition to the standard ANN operations. It makes it possible to build both perceptual and associative functions including learning and selforganization together with motor pattern generation and control, in the same ANS and to let these different systems interact. The basic building blocks for specifying multi-network structures are populations, i.e. sets of units with common properties, activation function etc. (possibly with some distribution in some properties) and projections, i.e. bundles of connections between a prepopulation and a postpopulation or postprojection. A population has spiking units with a passive membrane time constant and with adaptation (which is important to have e.g. in CPG:s). There are linear, exponential, and logarithmic transfer functions. The connections can be delayed and they can integrate over time, i.e. be fast or slow etc. Projections may be n:m or 1:1 configured and fixed or modifiable. Sparse connectivity is not yet included but should be handled efficiently for scaling to networks with large numbers of units. There is an interface to the environment in the form of sensors and actuators. It is set up to be run as a controller process, in parallel with e.g. a robot simulator, under SIMON , a simple multi-processing tool developed within SANS.

This simulator exists in a beta version and a lot more remains to be done with it. It is not yet general enough to allow implementation of any neural paradigm or mixing of paradigms. At present, its core is Bayesian neural networks aimed at unsupervised and reinforcement learning and it will also implement self-organization which fits nicely in this context. Other important activities concern improving the user interaction as well as parallel and distributed implementation.


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