3,089 research outputs found
Calling Dunbar's Numbers
The social brain hypothesis predicts that humans have an average of about 150
relationships at any given time. Within this 150, there are layers of friends
of an ego, where the number of friends in a layer increases as the emotional
closeness decreases. Here we analyse a mobile phone dataset, firstly, to
ascertain whether layers of friends can be identified based on call frequency.
We then apply different clustering algorithms to break the call frequency of
egos into clusters and compare the number of alters in each cluster with the
layer size predicted by the social brain hypothesis. In this dataset we find
strong evidence for the existence of a layered structure. The clustering yields
results that match well with previous studies for the innermost and outermost
layers, but for layers in between we observe large variability.Comment: 7 pages, 6 figure
Kanerva's sparse distributed memory with multiple hamming thresholds
If the stored input patterns of Kanerva's Sparse Distributed Memory (SDM) are highly correlated, utilization of the storage capacity is very low compared to the case of uniformly distributed random input patterns. We consider a variation of SDM that has a better storage capacity utilization for correlated input patterns. This approach uses a separate selection threshold for each physical storage address or hard location. The selection of the hard locations for reading or writing can be done in parallel of which SDM implementations can benefit
Neural networks and MIMD-multiprocessors
Two artificial neural network models are compared. They are the Hopfield Neural Network Model and the Sparse Distributed Memory model. Distributed algorithms for both of them are designed and implemented. The run time characteristics of the algorithms are analyzed theoretically and tested in practice. The storage capacities of the networks are compared. Implementations are done using a distributed multiprocessor system
Scaling of random spreading in small world networks
In this study we have carried out computer simulations of random walks on
Watts-Strogatz-type small world networks and measured the mean number of
visited sites and the return probabilities. These quantities were found to obey
scaling behavior with intuitively reasoned exponents as long as the probability
of having a long range bond was sufficiently low.Comment: 3 pages, 4 figure
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