What is Meta-Learning in Machine Learning?

Meta-Learning is a subfield of machine learning where automatic learning algorithms are applied on meta-data. In brief, it means Learning to Learn. The main goal is to use meta-data to understand how automatic learning can become flexible in solving different kinds of learning problems, hence to improve the performance of existing learning algorithms. Which means that how effectively we can increase the learning rate of our algorithms.

Meta-Learning affects the hypothesis space for the learning algorithm by either:

  • Changing the hypothesis space of the learning algorithms (hyper-parameter tuning, feature selection)
  • Changing the way the hypothesis space is searched by the learning algorithms (learning rules)

Variations of Meta-Learning: 

  • Algorithm Learning (selection) – Select learning algorithms according to the characteristics of the instance.
  • Hyper-parameter Optimization – Select hyper-parameters for learning algorithms. The choice of the hyper-parameters influences how well you learn.
  • Ensemble Methods – Learn to learn “collectively” – Bagging, Boosting, Stacked Generalization.

Flexibility is very important because each learning algorithm is based on a set of assumptions about the data, its inductive bias. This means that it will only learn well if the bias matches the data in the learning problem. A learning algorithm may perform very well on one learning problem, but very badly on the next. From a non-expert point of view, this poses strong restrictions on the use of machine learning or data mining techniques, since the relationship between the learning problem (often some kind of database) and the effectiveness of different learning algorithms is not yet understood.

By using different kinds of meta-data, like properties of the learning problem, algorithm properties (like performance measures), or patterns previously derived from the data, it is possible to select, alter or combine different learning algorithms to effectively solve a given learning problem. Critiques of meta-learning approaches bear a strong resemblance to the critique of metaheuristic, which can be said to be a related problem.

Metalearning may be the most ambitious but also the most rewarding goal of machine learning. There are few limits to what a good meta-learner will learn. Where appropriate it will learn to learn by analogy, by chunking, by planning, by subgoal generation, etc.

OpenAI’s Virtual Wrestling Bots

OpenAI, a firm backed by Elon Musk, has currently revealed one of it’s latest developments in the fields of Machine Learning, demonstrated using the technology of virtual sumo wrestlers.

OpenAI_wrestling

These are the bots inside the virtual world of RoboSumo controlled my machine learning. They (The Bots) taught themselves through trial and error using Reinforcement Learning, a technique inspired by the way animals learn through feedback. It has proved useful for training computers to play games and to control robots. The virtual wrestlers might look slightly ridiculous, but they are using a very clever approach to learning in a fast-changing environment while dealing with an opponent. This game and it’s virtual world were created at OpenAI to show how forcing AI systems to compete can spur them to become more intelligent.

However, one of the disadvantages of reinforcement learning is that doesn’t work well in realistic situations, or where things are more dynamic. OpenAI devised a solution to this problem by creating its own reinforcement algorithm called proximal policy optimization (PPO), which is especially well suited to changing environments.

The latest work, done in collaboration with researchers from Carnegie Mellon University and UC Berkeley, demonstrates a way for AI agents to apply what the researchers call a “meta-learning” framework. This means the agents can take what they have already learned and apply it to a new situation.

Inside the RoboSumo environment (see video above), the agents started out behaving randomly. Through thousands of iterations of trial and error, they gradually developed the ability to move—and, eventually, to fight. Through further iterations, the wrestlers developed the ability to avoid each other, and even to question their own actions. This learning happened on the fly, with the agents adapting even they wrestled each other.

Flexible learning is a very important part of human intelligence, and it will be crucial if machines are going to become capable of performing anything other than very narrow tasks in the real world. This kind of learning is very difficult to implement in machines, and the latest work is a small but significant step in that direction.

 

(sources: MitTechReview, OpenAI Blog, Wired)

NVIDIA’S CHIPS FOR COMPLETE CONTROL OF DRIVERLESS CARS

The race for autonomy in cars is ubiquitous. Top car brands are working in providing complete autonomous vehicles to their customers and the future with self-driving vehicles is inevitable. Adding the cherry to the cake, Nvidia’s recently announced chip is the latest generation of its DrivePX onboard car computers called Pegasus. The device is 13 times faster than the previous iteration, which has so far been used by the likes of Audi, Tesla, and Volvo to provide semi-autonomous driving capabilities in their vehicles.

nvidia_pegasus

Nvidia Pegasus

At the heart of this semiconductor is the mind-boggling technology of Deep Learning. “In the old world, the more powerful your engine, the smoother your ride will be,” Huang said during the announcement. “In the future, the more computational performance you have, the smoother your ride will be.”

Nvidia asserts that the device is only about the size of a license plate. But it has enough power to process data from up to 16 sensors, detect objects, find the car’s place in the world, plan a path, and control the vehicles itself. Oh, and it will also update centrally stored high-definition maps at the same time—all with some resources to spare.

The new system is designed to eventually handle up to 320 trillion operations per second (TOPS), compared to the 24tn of today’s technology. That would give it the power needed to process the masses of data produced by a vehicle’s cameras and other sensors and allow it to drive completely autonomously, Nvidia said. The first systems to be tested next year will have less processing power but will be designed to scale up with the addition of extra chips.

 

(sources: MitTechReview, NvidiaBlog)

Origami-inspired Robots

In a bid to augment the robots’ abilities, researchers at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have come up with a new tool: origami exoskeletons.

In a paper published recently, researchers describe four exoskeletons, each made out of a plastic sheet that folds into a predefined shape when heated for a few seconds. There’s a boat-shaped exoskeleton and a glider: one for “walking,” and another that folds up into a crude wheel for faster movement. Each exoskeleton can be donned in turn by a tiny lead bot called Primer. This isn’t a robot as we usually think of them, but a small magnetic cube that can be controlled remotely using magnetic fields.

“If we want robots to help us do things, it’s not very efficient to have a different one for each task,” said CSAIL’s Daniela Rus, the project’s lead, in a press release. “With this metamorphosis-inspired approach, we can extend the capabilities of a single robot by giving it different ‘accessories’ to use in different situations.” In the future, the researchers imagine this sort of approach to robot design could help up make multifunctional bots that can perform complex tasks remotely. They could be used for deep-sea mining operations, for example, or for building colonies in space. These are locations where you don’t want to waste resources shipping out lots of different bots for different jobs, so it’s more efficient to send one with a set of origami tools. As Rus says: “Why update a whole robot when you can just update one part of it?”

Watch the video below for getting a better idea of the origami-inspired robots.

 

(Source : CSAIL, TheVerge, ScienceDaily )