Tag Archives: model
#436414 Japanese Researchers Teaching Robots to ...
When mobile manipulators eventually make it into our homes, self-repair is going to be a very important function. Hopefully, these robots will be durable enough that they won’t need to be repaired very often, but from time to time they’ll almost certainly need minor maintenance. At Humanoids 2019 in Toronto, researchers from the University of Tokyo showed how they taught a PR2 to perform simple repairs on itself by tightening its own screws. And using that skill, the robot was also able to augment itself, adding accessories like hooks to help it carry more stuff. Clever robot!
To keep things simple, the researchers provided the robot with CAD data that tells it exactly where all of its screws are.
At the moment, the robot can’t directly detect on its own whether a particular screw needs tightening, although it can tell if its physical pose doesn’t match its digital model, which suggests that something has gone wonky. It can also check its screws autonomously from time to time, or rely on a human physically pointing out that it has a screw loose, using the human’s finger location to identify which screw it is. Another challenge is that most robots, like most humans, are limited in the areas on themselves that they can comfortably reach. So to tighten up everything, they might have to find themselves a robot friend to help, just like humans help each other put on sunblock.
The actual tightening is either super easy or quite complicated, depending on the location and orientation of the screw. If the robot is lucky, it can just use its continuous wrist rotation for tightening, but if a screw is located in a tight position that requires an Allen wrench, the robot has to regrasp the tool over and over as it incrementally tightens the screw.
Image: University of Tokyo
In one experiment, the researchers taught a PR2 robot to attach a hook to one of its shoulders. The robot uses one hand to grasp the hook and another hand to grasp a screwdriver. The researchers tested the hook by hanging a tote bag on it.
The other neat trick that a robot can do once it can tighten screws on its own body is to add new bits of hardware to itself. PR2 was thoughtfully designed with mounting points on its shoulders (or maybe technically its neck) and head, and it turns out that it can reach these points with its manipulators, allowing to modify itself, as the researchers explain:
When PR2 wants to have a lot of things, the only two hands are not enough to realize that. So we let PR2 to use a bag the same as we put it on our shoulder. PR2 started attaching the hook whose pose is calculated with self CAD data with a driver on his shoulder in order to put a bag on his shoulder. PR2 finished attaching the hook, and the people put a lot of cans in a tote bag and put it on PR2’s shoulder.
“Self-Repair and Self-Extension by Tightening Screws based on Precise Calculation of Screw Pose of Self-Body with CAD Data and Graph Search with Regrasping a Driver,” by Takayuki Murooka, Kei Okada, and Masayuki Inaba from the University of Tokyo, was presented at Humanoids 2019 in Toronto, Canada. Continue reading
Posted in Human Robots
#436258 For Centuries, People Dreamed of a ...
This is part six of a six-part series on the history of natural language processing.
In February of this year, OpenAI, one of the foremost artificial intelligence labs in the world, announced that a team of researchers had built a powerful new text generator called the Generative Pre-Trained Transformer 2, or GPT-2 for short. The researchers used a reinforcement learning algorithm to train their system on a broad set of natural language processing (NLP) capabilities, including reading comprehension, machine translation, and the ability to generate long strings of coherent text.
But as is often the case with NLP technology, the tool held both great promise and great peril. Researchers and policy makers at the lab were concerned that their system, if widely released, could be exploited by bad actors and misappropriated for “malicious purposes.”
The people of OpenAI, which defines its mission as “discovering and enacting the path to safe artificial general intelligence,” were concerned that GPT-2 could be used to flood the Internet with fake text, thereby degrading an already fragile information ecosystem. For this reason, OpenAI decided that it would not release the full version of GPT-2 to the public or other researchers.
GPT-2 is an example of a technique in NLP called language modeling, whereby the computational system internalizes a statistical blueprint of a text so it’s able to mimic it. Just like the predictive text on your phone—which selects words based on words you’ve used before—GPT-2 can look at a string of text and then predict what the next word is likely to be based on the probabilities inherent in that text.
GPT-2 can be seen as a descendant of the statistical language modeling that the Russian mathematician A. A. Markov developed in the early 20th century (covered in part three of this series).
GPT-2 used cutting-edge machine learning algorithms to do linguistic analysis with over 1.5 million parameters.
What’s different with GPT-2, though, is the scale of the textual data modeled by the system. Whereas Markov analyzed a string of 20,000 letters to create a rudimentary model that could predict the likelihood of the next letter of a text being a consonant or a vowel, GPT-2 used 8 million articles scraped from Reddit to predict what the next word might be within that entire dataset.
And whereas Markov manually trained his model by counting only two parameters—vowels and consonants—GPT-2 used cutting-edge machine learning algorithms to do linguistic analysis with over 1.5 million parameters, burning through huge amounts of computational power in the process.
The results were impressive. In their blog post, OpenAI reported that GPT-2 could generate synthetic text in response to prompts, mimicking whatever style of text it was shown. If you prompt the system with a line of William Blake’s poetry, it can generate a line back in the Romantic poet’s style. If you prompt the system with a cake recipe, you get a newly invented recipe in response.
Perhaps the most compelling feature of GPT-2 is that it can answer questions accurately. For example, when OpenAI researchers asked the system, “Who wrote the book The Origin of Species?”—it responded: “Charles Darwin.” While only able to respond accurately some of the time, the feature does seem to be a limited realization of Gottfried Leibniz’s dream of a language-generating machine that could answer any and all human questions (described in part two of this series).
After observing the power of the new system in practice, OpenAI elected not to release the fully trained model. In the lead up to its release in February, there had been heightened awareness about “deepfakes”—synthetic images and videos, generated via machine learning techniques, in which people do and say things they haven’t really done and said. Researchers at OpenAI worried that GPT-2 could be used to essentially create deepfake text, making it harder for people to trust textual information online.
Responses to this decision varied. On one hand, OpenAI’s caution prompted an overblown reaction in the media, with articles about the “dangerous” technology feeding into the Frankenstein narrative that often surrounds developments in AI.
Others took issue with OpenAI’s self-promotion, with some even suggesting that OpenAI purposefully exaggerated GPT-2s power in order to create hype—while contravening a norm in the AI research community, where labs routinely share data, code, and pre-trained models. As machine learning researcher Zachary Lipton tweeted, “Perhaps what's *most remarkable* about the @OpenAI controversy is how *unremarkable* the technology is. Despite their outsize attention & budget, the research itself is perfectly ordinary—right in the main branch of deep learning NLP research.”
OpenAI stood by its decision to release only a limited version of GPT-2, but has since released larger models for other researchers and the public to experiment with. As yet, there has been no reported case of a widely distributed fake news article generated by the system. But there have been a number of interesting spin-off projects, including GPT-2 poetry and a webpage where you can prompt the system with questions yourself.
Mimicking humans on Reddit, the bots have long conversations about a variety of topics, including conspiracy theories and
Star Wars movies.
There’s even a Reddit group populated entirely with text produced by GPT-2-powered bots. Mimicking humans on Reddit, the bots have long conversations about a variety of topics, including conspiracy theories and Star Wars movies.
This bot-powered conversation may signify the new condition of life online, where language is increasingly created by a combination of human and non-human agents, and where maintaining the distinction between human and non-human, despite our best efforts, is increasingly difficult.
The idea of using rules, mechanisms, and algorithms to generate language has inspired people in many different cultures throughout history. But it’s in the online world that this powerful form of wordcraft may really find its natural milieu—in an environment where the identity of speakers becomes more ambiguous, and perhaps, less relevant. It remains to be seen what the consequences will be for language, communication, and our sense of human identity, which is so bound up with our ability to speak in natural language.
This is the sixth installment of a six-part series on the history of natural language processing. Last week’s post explained how an innocent Microsoft chatbot turned instantly racist on Twitter.
You can also check out our prior series on the untold history of AI. Continue reading
Posted in Human Robots