Title
Learning over sets with Recurrent Neural Networks: An empirical categorization of aggregation functions
Abstract
Numerous applications benefit from parts-based representations resulting in sets of feature vectors. To apply standard machine learning methods, these sets of varying cardinality need to be aggregated into a single fixed-length vector. We have evaluated three common Recurrent Neural Network (RNN) architectures, Elman, Williams & Zipser and Long Short Term Memory networks, on approximating eight aggregation functions of varying complexity. The goal is to establish baseline results showing whether existing RNNs can be applied to learn order invariant aggregation functions. The results indicate that the aggregation functions can be categorized according to whether they entail (a) selection of a subset of elements and/or (b) non-linear operations on the elements. We have found that RNNs can very well learn to approximate aggregation functions requiring either (a) or (b) and those requiring only linear sub functions with very high accuracy. However, the combination of (a) and (b) cannot be learned adequately by these RNN architectures, regardless of size and architecture.
Year
DOI
Venue
2011
10.1016/j.matcom.2010.10.018
Mathematics and Computers in Simulation
Keywords
Field
DocType
Recurrent Neural Networks,Order invariance,Aggregation
Categorization,Feature vector,Recurrent neural network,Cardinality,Long short term memory,Invariant (mathematics),Artificial intelligence,Mathematics,Machine learning
Journal
Volume
Issue
ISSN
82
3
0378-4754
Citations 
PageRank 
References 
0
0.34
11
Authors
4
Name
Order
Citations
PageRank
Wolfgang Heidl11037.01
C. Eitzinger260.96
M. Gyimesi330.75
F Breitenecker442.16