Failures and breakthroughs – exposed, reflected, considered

How GANs can turn AI into a massive force

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Deep learning models can already achieve state-of-the-art results in some applications, but their capabilities are still limited. Unlike humans, deep learning models are unable to handle minor changes, and hence can only be applied for specific and narrowly defined tasks.

Consider this conversation of what might be the most sophisticated negotiation software on the planet, which occurred between two AI agents developed at Facebook:

Bob: “I can can I I everything else.”

Alice: “Balls have zero to me to me to me to me to me to me to me to me to.”

At first, they were speaking in plain old English, but researchers realized they forgot to include a reward for sticking to the language. So, the AI agents began to diverge, eventually rearranging legible words into seemingly nonsensical (but, in their perspective, highly efficient) sentences. They invented their own codewords, abbreviations, and structures.

This phenomenon is observed again and again and again.

A vanguard AI technology that can learn, recognize, and generate information on a nearly human level doesn’t exist yet, but we have taken steps toward that direction.

What are generative adversarial networks (GANs)?

Generally intelligent systems must be able to generalize from limited data and learning causal relationships. In 2016, Ian Goodfellow, a fellow at Google Brain, suggested using generative adversarial networks (GANs) as an alternative unsupervised machine learning method. This aimed to address many of the ailing points of the existing methods.

GANs consist of two deep neural networks: generator and discriminator. The generator’s goal is to create data samples that are so indistinguishable to the real ones. The discriminator’s goal is to identify which of the generator’s data samples are real and which are fake.

These two networks compete against each other in a zero-sum game (i.e. one’s loss implies another’s win). Both networks would then become stronger in a relatively short period of time.

gan-chart

Backpropagation is used to update the model parameters and train the neural networks. Over time, the networks learn many features of the provided data. To create realistic forged samples, the generator needs to learn the data’s features and patterns, while the discriminator does the same to correctly distinguish between real and fake samples.

GANs are thus able to overcome the above weaknesses by training (i.e. playing) neural networks against each other, thus learning from each other (which necessitates less data) and eventually performing better in a broader range of problems.

Applications of GANs

There are several types of GANs, and some of its most obvious applications include high-resolution or interactive image generation/blendingimage inpaintingimage-to-image translation, abstract reasoning, semantic segmentation, video generation, and text-to-image synthesis, among others.

The video game industry is the first area of entertainment to start seriously experimentingusing AI to generate raw content. There’s a huge cost incentive to invest in video game development automation given the US$300 million+ budget of modern AAA video games.

GANs have also been used for text, with less success⏤a bot developed to speak like Friedrich Nietzsche started to speak in a manner similar to the philosopher, but the sentences did not make sense. GANs for voice applications are able to reproduce a given text string to life-like voices with approximately 20 minutes of voice samples, such as these popular impersonations of American presidents Donald Trump and Barack Obama. In the near future, videos can likely be generated just by providing a script.

Goodfellow and his colleagues used GANs for image generation, recognition, and classification by teaching one of the networks to create images of handwritten digits (humans were not able to distinguish real handwritten digits). They also trained a neural network to create images of objects, which humans could only differentiate (from real ones) 78.7 percent of the time. Below are some sample images of faces created entirely by deep convolutional GANs.
face-samples-gan

Despite all the above achievements, GANs still have weaknesses:

  • Instability (the generator and the discriminator losses keep oscillating) and non-convergence (to optimum) of the objective function in GANs
  • Mode collapse (this happens when the generator doesn’t produce diverse images or information)
  • The possibility that either the generator or the discriminator becomes too strong as compared to the others during training
  • The possibility that either the generator or the discriminator never learns beyond a certain point

An existential threat

Do GANs and AI in general pose an existential threat to humanity? Elon Musk thinks so. Since 2014, he has been advocating adoption of AI regulations by authorities around the world. Recently, he reiterated the urgent need to be proactive in regulation.

“AI is a fundamental risk to the existence of human civilization,” Musk tells US politicians recently.

His concerns stem from the rapid developments related to GANs, which might push humanity toward the inception of artificial general intelligence. While AI regulations may serve as safeguards, AI is still far from the fictitious depictions seen frequently in Hollywood sci-fi movies.

(By the way, Facebook ultimately opted to require its negotiation bots to speak in plain old English.)

Here are some recommended resources for GAN:

This article originally appeared on Tech in Asia.

Written by Hayk

January 26, 2018 at 7:47 pm

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