Friday, October 30, 2015

Pedro Domingos’ on “Five Machine Learning Tribes”

Connectionists

By contrast, Domingos said, a group called “connectionists” wants to reverse engineer the brain.

This very ambitious approach involves actually creating artificial neurons and connecting them in a neural network. Domingos calls this approach “deep learning” and shows how companies like Google are applying it to areas like vision and image processing, machine translation and experimental neural networks like Google's Cat Network that helps the computer to recognize cat images.

Taking the example of a cat image network, Domingos talks about how neurons work on a weighted value of inputs, and how binary results can be enhanced into a “continuous value” with methods like back propagation. All of this leads the computer to be able to learn more about a given set of information criteria – in this case, about what is and is not a cat, to be able to more correctly label random sets of images.

The Evolutionaries

Another radically different approach, says Domingos, involves looking at evolution as a phenomenon.

“Evolution made your brain and everything else,” says Domingos, articulating the idea and philosophy behind the evolutionary mindset. “So it must be a good thing.”

In essence, Domingos says, evolutionaries are applying the idea of genomes and DNA in the evolutionary process to data structures. The survival and offspring of units in an evolutionary model are the performance data. An algorithm for an evolutionary learning project would mimic those processes in key ways.

Domingos likens it to farmers and what they do with selective breeding, but notes that because the process is being applied to specific technologies, the model is a bit different. However, using the example of robotic selection, he goes into detail about a process of “robot evolution”, and how researchers can start with random assemblies and 3D print the best performing models.

“You wind up with surprisingly smart and robust robots,” says Domingos. “You can learn surprisingly powerful things this way.”

The Bayesians

The Bayesians, Domingos says, deal in uncertainty and solutions. Their master algorithm solution is called probabilistic inference.

Domingos explains that researchers can take a hypothesis and apply a type of “a priori” thinking, believing that there will be some outcomes that are more likely. They then update a hypothesis as they see more data.

“After some iteration of this,” Domingos says. “Some hypotheses become more likely than others.”

Domingos talks about strategies for efficient computing that support this process. He mentions vision learning applied to spam filtering, which is a key way to stop spammers from clogging up user inboxes. As another sort of scientific process, the probabilistic models do bring a certain concrete result to Machine Learning

The Analogizers

The fifth tribe of Machine Learning philosophers, Domingos says, is made up of analogizers, or pioneers in the field of matching particular bits of data to each other. Although it sounds simple and rudimentary, Domingos says it's really at the heart of a lot of outcomes that are extremely effective for some kinds of Machine Learning. He cites one of the leading proponents of this method, Douglas Hofstadter, in saying that “all intelligence is nothing but analogy.”

The master algorithm here, he says, is the “nearest neighbor” principle. Nearest neighbor outcomes can give results that are similar to neural network models. Domingos gives the example of two country models with defined city locations, but with undefined borders. Through the application of the analogy principles, the computer generates a likely border. Domingos calls this “generalizing from similarity” and suggests that it has economic ramifications for technology. One example, he says, is the movie advice technologies that supply movie ratings based on known data sets, where users get recommendations based off of what others have watched previously.

“It's a very nice type of similarity-based learning.” Domingos says, adding another example of how real results can boost profits for companies: one third of Amazon sales, he says, are based on recommendations.

Tribes Come Together

In closing, Domingos talks about how all five of these tribes have something key to offer and how the best Machine Learning technologies combine all five angles. In addition, he says, some new ideas are also needed to further refine Machine Learning into something that would give us the future outcomes we’ve anticipated for a long time, including things like cancer cures, home robots, and worldwide neural networks.

“This is only the beginning,” Domingos says. “There's much more that remains to be done.”


Indeed, these Machine Learning technologies are rapidly advancing toward future results that will change the ways that we view our interactions with computers and digital technologies. Some of that future depends on the work of these five “tribes” and how they can push the boundaries of what’s possible with Artificial Intelligence.


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