Posts

  • A Response to Anti-Representationalists

      I like to see myself as an open person, and occasionally make efforts to increase my openness to ideas. Coming from a background in cognitive science where representationalist positions are the norm, I have read literature on non-representationalist viewpoints such as Lawrence Shapiro’s “Embodied Cognition” and O’Regan’s work on Sensorimotor Theory of Consiousness to put my work in perspective. I remember being unconvinced of their arguments as representations of some form still seemed necessary. Fast-forward about three years where I am now working daily on artificial neural networks and “deep learning” is in my basic vocabulary. Recently, I’ve come across this article many times through media outlets Reddit and Facebook by the renowned Robert Epstein voicing his position against using computational metaphors for the brain. Here, I give my response to his positions from my short experience doing research in machine learning and artificial intelligence given my background in cognitive psychology. Please share your thoughts!

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  • Visualizing CIFAR-10 Categories with WordNet and NetworkX

      In this post, I will describe how the object categories from CIFAR-10 can be visualized as a semantic network. CIFAR-10 is a database of images that is used by the computer vision community to benchmark the performance of different learning algorithms. For some of the work that I’m currently working on, I was interested in the semantic relations between the object categories, as other research has been in the past. We can do this by defining their relations with WordNet and then visualizing them using NetworkX combined with Graphviz.

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  • Topographic Locally Competitive Algorithm

      Recent studies have shown that, in addition to the emergence of receptive fields similar to those observed in biological vision using sparse representation models, the self organization of said receptive fields can emerge from group sparsity constraints. Here I will briefly review research demonstrating topological organization of receptive fields using group sparsity principles and then describe a two-layer model implemented in a Locally Comptetitive Algorithm that will be termed Topographical Locally Competitive Algorithm (tLCA).

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  • Sparse Filtering in Theano

      Sparse Filtering is a form of unsupervised feature learning that learns a sparse representation of the input data without directly modeling it. This algorithm is attractive because it is essentially hyperparameter-free making it much easier to implement relative to other existing algorithms, such as Restricted Boltzman Machines, which have a large number of them. Here I will review a selection of sparse representation models for computer vision as well as Sparse Filtering’s place within that space and then demonstrate an implementation of the algorithm in Theano combined with the L-BFGS method in SciPy’s optimizaiton library.

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