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The Top A.I. Breakthroughs of 2015


Learn about the biggest developments of 2015 in the field of Artificial Intelligence.



Creative Abstract Thought

Beyond understanding simple concepts lies grasping aspects of causal structure — understanding how ideas tie together to make things happen or tell a story in time — and to be able to create things based on those understandings. Building on the basic ideas from both DeepMind’s neural Turing machine and Facebook’s memory networks, combinations of deep learning and novel memory architectures have shown great promise in this direction this year. These architectures provide each node in a deep neural network with a simple interface to memory.

Kumar and Socher’s dynamic memory networks improved on memory networks with better support for attention and sequence understanding. Like the original, this system could read stories and answer questions about them, implicitly learning 20 kinds of reasoning, like deduction, induction, temporal reasoning, and path finding. It was never programmed with any of those kinds of reasoning. Weston et al’s more recent end-to-end memory networks then added the ability to perform multiple computational hops per output symbol, expanding modeling capacity and expressivity to be able to capture things like out-of-order access, long term dependencies, and unordered sets, further improving accuracy on such tasks.

Programs themselves are of course also data, and they certainly make use of complex causal, structural, grammatical, sequence-like properties, so programming is ripe for this approach. Last year, neural Turing machines proved deep learning of programs to be possible. This year, Grefenstette et al. showed how programs can be transduced, or generatively figured out from sample output, much more efficiently than with neural Turing machines, by using a new type of memory-based recurrent neural networks (RNNs) where the nodes simply access differentiable versions of data structures such as stacks and queues. Reed and de Freitas of DeepMind have also recently shown how their neural programmer-interpreter can represent lower-level programs that control higher-level and domain-specific functionalities.

Another example of proficiency in understanding time in context, and applying that to create new artifacts, is a rudimentary but creative video summarization capability developed this year. Park and Kim from Seoul National U. developed a novel architecture called a coherent recurrent convolutional network, applying it to creating novel and fluid textual stories from sequences of images.

convolutional_neural_network

Another important modality that includes causal understanding, hypotheticals, and creativity in abstract thought is scientific hypothesizing. A team at Tufts combined genetic algorithms and genetic pathway simulation to create a system that arrived at the first significant new AI-discovered scientific theory of how exactly flatworms are able to regenerate body parts so readily. In a couple of days it had discovered what eluded scientists for a century. This should provide a resounding answer to those who question why we would ever want to make AIs curious in the first place.

Dreaming Up Visions

AI did not stop at writing programs, travelogues, and scientific theories this year. There are AIs now able to imagine, or using the technical term, hallucinate, meaningful new imagery as well. Deep learning isn’t only good at pattern recognition, but indeed pattern understanding and therefore also pattern creation.

team from MIT and Microsoft Research have created a deep convolution inverse graphic network, which, among other things, contains a special training technique to get neurons in its graphics code layer to differentiate to meaningful transformations of an image. In so doing, they are deep-learning a graphics engine, able to understand the 3D shapes in novel 2D images it receives, and able to photorealistically imagine what it would be like to change things like camera angle and lighting.

team from NYU and Facebook devised a way to generate realistic new images from meaningful and plausible combinations of elements it has seen in other images. Using a pyramid of adversarial networks — with some trying to produce realistic images and others critically judging how real the images look — their system is able to get better and better at imagining new photographs. Though the examples online are quite low-res, offline I’ve seen some impressive related high-res results.

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