The Focus-Project team Ballbot consists of eight future mechanical engineers, studying at the ETH Zurich, two electrical engineers studying at the ZHAW as well as the Industrial Designers educated at ZHdK. Through the combination of our skills and ideas we aim to complete an unprecedented project which develops a new concept of movement. Our team with its task is supervised by Prof. Dr. Roland Siegwart, Director of the ASL at ETH Zurich.
Unlike Kumagai's ballbot, one focus of the Rezero is design:
Rezero is meant to entertain and impress. It is supposed to create emotions. It will be able to interact with a small group of people, react on attractions and in doing so create a hands-on experience with the Ballbot technology. The Ballbot will be an ambassador of its own movement skills. Its dynamic hull even allows Rezero to show and create emotions. Imagine Rezero breathing, being curious or frightened. And even waking up or going to sleep by revealing or retracting its sphere.
Another focus is improved dynamics: To push the boundaries of current ballbots, the team uses a custom-made motor controller in combination with high-performance engines and a specially coated ball. This allows Rezero to move fast - at speeds up to 3.5m/s and with inclinations up to 17 degrees - and to perform unique movements, such as moving with high inclinations while simultaneously rotating around its vertical axis.
Now that we’ve reviewed both the iRobot Roomba 560 and the Neato XV-11, you’re probably wondering which one you should get. There’s no easy answer, but in this post we’ll highlight the features of each robot and the differences between them, so that you can decide which one is right for you.
If you haven’t read our individual reviews of each robot, you can get lots more detail at the following links:
Both robots are approximately the same size, with two driver wheels underneath and a touch sensing bumper at the front. The Roomba is round, allowing it to turn all the way around in place, while the XV-11 has a square front to help it get into corners more effectively.
The XV-11 is slightly taller:
This means that if you have furniture that’s within that height difference, the Roomba will clean underneath it but the XV-11 won’t. The XV-11 is just under 4 inches tall, while the Roomba is a bit over 3.
Both robots have a built-in carrying handle. The XV-11 is a little bit heavier. They both seem very solid and robust (although you probably want to avoid dropping them), and both come with a one year warranty.
Both robots include one button cleaning, meaning that whatever else they can do, at the very least you can just push the big “clean” button on them and they’ll go vacuum. The Roomba 560 has additional dedicated displays for scheduling cleaning times, while the XV-11 has a small multipurpose LCD display.
Both robots come with charging docks that they can return to autonomously. The Roomba’s dock is drive-on, which means that the robot charges by driving onto a little platform. The XV-11’s dock is drive-up, which means that the robot presses against the dock. The XV-11’s dock includes a storage compartment for the power adapter, which is a useful feature, since you can store the adapter inside the dock if you don’t need the extra power cord length. Both robots will attempt to ’snug’ back up to their charging contacts if they get accidentally moved.
The Roomba 560 and the Neato XV-11 both allow for on-board scheduling. You can set different times for each day of the week, and the robot will undock, clean, and redock to recharge itself. It’s relatively easy to program this on both robots, although the XV-11’s LCD makes it a bit easier.
Due to its LCD, the XV-11 has a distinct advantage when it comes to user communication. The screen tells you if you need to perform maintenance tasks, or what to do if the robot isn’t doing what it’s supposed to be doing. The Roomba will sometimes speak in a female voice when it needs assistance, but for more obscure technical issues it just beeps, and you need to keep track of the number of beeps and look up what they mean online, which is far less convenient.
Both robots come accessories that you can use to keep them away from certain areas. The XV-11 uses a magnetic strip (you get 15 feet of it and can buy more for $30) that you place on the floor, and the robot will clean up to it but not go over. You can cut the strip up, and it sort of bends enough to make curves. The Roomba uses Virtual Walls, which are little towers about the size of a coffee cup that project infrared beams which the robot won’t cross over, so you can leave them up around doorways and stuff even when the robot isn’t vacuuming. The beams will reach out to about 8 feet, and the Virtual Walls run on batteries. The 560 comes with two, and buying another one will cost you $40.
The Roomba and the Neato XV-11 use significantly different techniques to vacuum areas. The Roomba uses a variety of cleaning behaviors to cover a room, using input from its sensors to decide where to go next. It doesn’t know where it has or has not been in the absolute sense, but on average, it will cover each area of a room 3-4 times, which helps it to clean more thoroughly.
The XV-11, on the other hand, has a laser sensor that creates a map of walls, doorways, and obstacles. The robot then plans a route to cover the entire area efficiently, generally with a single pass over most points.
We should point out that neither the XV-11 nor the Roomba is a total replacement for a human wielding an upright vacuum with a hose attachment. Rather, they’re maintenance tools, designed to minimize the amount of vacuuming that you have to do. That said, we found both robots to clean very effectively on hardwood, comparable to a conventional upright vacuum over most of the floor. Because of their shapes, however, the robots aren’t quite as good close to obstacles, along walls, and in corners.
The XV-11 is better at cleaning along walls and corners in most cases, since its square front allows it to get in closer, although it doesn’t always get into corners in the ideal orientation. Because the Roomba is round, it relies on a spinning brush to sweep into corners, which is less effective than getting the entire vacuum in there. It’s worth noting, though, that this spinning brush extends beyond the reach of the vacuum, outside the body of the robot, which means that the Roomba can (sort of) clean beyond its own chassis, while the XV-11 can’t. The effectiveness of the spinning brush is mediocre at best, however, since it often just kicks dirt somewhere else where the Roomba may or may not get later. Basically, neither robot can make up for the hose attachment on a conventional upright vacuum when it comes to tight areas.
On carpet, both the XV-11 and the Roomba did fairly well, although not as good as an upright. The Roomba cleaned slightly better in general, and significantly better when it came to pet hair, probably because of its bristle brush. The rubber brush on the XV-11 tended to leave streaks of pet hair behind it. Neither robot got pet hair completely cleaned up, though, and they did especially poorly around table and chair legs. Also, iRobot has pointed out that crossing over carpet from multiple angles changes the nap of the carpet and is better for getting dirt out, which I tend to believe… The XV-11 cleans in a single pass.
The XV-11 is significantly faster than the Roomba, about four times faster, cleaning my living room in 12 minutes as opposed to the Roomba’s 45. This difference will increase as the robots are asked to clean larger rooms or more rooms. The XV-11 doesn’t move faster, but since it doesn’t cover most areas more than once, it’s done much faster. Also, it knows exactly where its dock is, and doesn’t have to spend time searching for it after it’s finished. Of course, if you’re taking advantage of the scheduling feature, these vacuums are running by themselves when you’re not home, in which case speed (and noise) may not matter nearly as much. In this case, the question changes from is it faster to how much area can each robot cover per charge, how long does it take to recharge, and how effectively can it resume coverage of multiple rooms? The XV-11 has a pronounced advantage here, because it cleans more efficiently: It spends significantly less time on each room, is better at finding its way from room to room (since it can see doorways), can more reliably find its way back to its charging dock if it needs to (since it creates a map), and then can return to exactly where it left off and finish cleaning without any redundancy in coverage. Some models of Roombas include Lighthouse technology which helps them clean multiple rooms more efficiently, but the 560 does not.
The XV-11 seems significantly louder than the Roomba; both are significantly quieter than an upright vacuum. We’re waiting for exact decibel numbers.
Both robots have minimal issues cleaning entirely autonomously, meaning that in general, you really can just let them do their thing from start to finish without having to worry about them getting lost or stuck.
Both robots require you to empty their dustbins on a regular basis. Depending on how many rooms you have them clean, and how dirty your floors get, this could be anywhere from every cleaning to every three cleanings or so. Both robots will inform you when their dustbins need to be changed, so it’s not something you really have to worry about… Although it’s better to empty them before they fill completely, especially if you have the robots clean autonomously.
The dustbin on the XV-11 is marginally easier to access than the one on the Roomba, since it lifts out of the top of the robot instead of out of the back. Also, the XV-11’s air filter keeps the dust in when you lift the bin out; you remove the filter to empty the bin. The Roomba’s bin doesn’t have a cover like that, so there’s the potential to make a huge mess unless you pull the bin out carefully and keep it in the correct orientation. The XV-11 also has a larger dustbin, but I wouldn’t call it significantly larger.
The air filters on both robots are easy to access and replace, being integrated into the dust bins themselves. Replacement filters for the XV-11 cost $19 for 6, and for the Roomba it’s $19 for 3.
The XV-11 is much better at keeping itself clean as it cleans, especially when it comes to hair (pet and otherwise). I have a couple cats, and while the Roomba was significantly better at picking up cat hair, it also got a lot of cat hair wrapped around its bristle brushes, as well around the bearings holding the brushes in place. After just a few vacuumings, you’ll need to take the brushes and bearings out and clean them by hand, which is a dirty and annoying process. iRobot includes a tool to help with this, but I’ve often had to resort to scissors and brute strength to get the hair out of the bristle brush. The XV-11, on the other hand, while not as good at picking up pet hair, remains very clean, on both its brush and bearings. After 3 rounds of my living room, the Roomba was very dirty and tangled underneath, while the XV-11 looked brand new.
Lastly, there are maintenance tasks that you shouldn’t have to do very often, or (ideally) at all, like replacing brushes, bearings, and batteries. We didn’t get a chance to test the XV-11 to this point, but my guess is that the XV-11 would be more resistant to bearing damage (something I’ve experienced with my own personal Roomba), simply because not as much stuff gets caught up in its cleaning system.
Both iRobot and Neato offer replacement components for their robots. iRobot’s website has nearly every component for the robot available, while Neato mostly focuses on accessories. I didn’t try to take either robot apart, so I can’t comment on how easy it is to replace major components, but I like the fact that iRobot gives you the option to try to fix things yourself.
The Neato XV-11 is currently on pre-order for $400, to be available “this summer.” The iRobot Roomba 560 is available now for $350. However, the Roomba 560 does not include the Lighthouse multi-room technology. To get that, you’d need to upgrade to the Roomba 570 for $450, which might be a more realistic robot to compare the XV-11 to in terms of multi-room cleaning capability. And even then, the XV-11 is still likely to be significantly better at cleaning multiple rooms due to its mapping technology.
So, to summarize:
-Both robots clean hardwood equally well, about as well as a traditional upright vacuum.
-The Roomba cleans carpet noticeably better than the XV-11, and is significantly better at picking up pet hair. Neither robot is as good at these tasks as a traditional upright vacuum.
-The Roomba requires significantly more maintenance than the XV-11, especially if it picks up hair of any kind.
-The XV-11 cleans rooms about four times as fast as the Roomba.
-The XV-11 is significantly better at cleaning multiple rooms than the Roomba.
-The XV-11 seems louder than the Roomba.
-The fact that the Roomba uses cleaning behaviors derived from foraging insects is very cool.
-The fact that the XV-11 uses a laser to map rooms is very cool.
There are a few other things to potentially consider… If cost is an issue, iRobot sells Roomba models that are less expensive than the 560. If you only need to clean one or two rooms, and don’t need the scheduling feature, you could get a Roomba 530 for $300.
Also, iRobot has been selling Roombas for a long time, while Neato is introducing a new product. The fifth generation of Roombas embodies many years of improvements and refinements while the XV-11 has yet to prove itself as a commercial product. That said, the mapping technology in the XV-11 is very impressive, and I feel like irrespective of which robot makes a better vacuum, there’s a lot of potential there.
What it comes down to, though, is that both the iRobot Roomba 560 and the Neato XV-11 are solid autonomous robot vacuums that use different techniques and technologies to get your floor clean and keep it that way without you having to lift a finger.
And once again, I’d encourage you to read our individual reviews of each robot, since there are lots more details (plus more pictures and video):
French company Robosoft has unveiled what it calls a "cybernetic transport system." The robuRIDE carries 30 passengers and reaches 24 kilometers per hour, driving autonomously using differential GPS and onboard sensors.
The vehicle weighs 3 metric tons, or 5 metric tons fully loaded. A 380-volt pack of lead acid batteries gives it 8 hours of autonomy. In automatic mode, it can follow a pre-recorded path. To drive it manually, you use a game controller.
A safety system relies on a laser scanner to avoid collisions. In the video below, the researcher demonstrates it by putting his body on the line. The vehicle detects him and slowly decelerates, stopping about 2 meters from him. Even if this system fails, a soft foam bumper stops the vehicle if it hits something, or someone.
Now my favorite part: According to the video, you can regulate the vehicle's cabin temperature by "opening windows and [using] fans." Elegant engineering.
This is the system's second generation, and the video shows a test conducted in France last month. The robuRIDE is part of Rome's Cybernetic Transport System, a program to implement a high-tech transportation infrastructure at the city's new convention center. Is this the future of mass transit?
Vincent Dupourque, CEO of Robosoft, says:
We have completed the 2nd generation of our robuRIDE, used to implement Cybernetic Transport Systems. It can reach 24 km/h with 30 passengers, and has a dynamic accuracy of a few centimeters, thanks to the hybrid navigation system based on GPS, inertial and odometry.
This video has been done during Factory Acceptance Tests of the robuRIDE for ROME Cybernetic Transport System, in May 2010, in Dax, Biarritz and Bidart. We explain here the vehicle and how it works, show how it can be transported from one site to another, and also some users give their first impressions.
In a remarkable demonstration of brain-machine interface technology, researchers at the University of Pittsburgh have taught a monkey to use just its thoughts to control an advanced robotic arm and perform elaborate maneuvers with it.
It's not the first time a monkey with sensors implanted in its brains has controlledmachines with its mind. But this seven-degrees-of-freedom robot arm is probably the most complex system a monkey has ever mastered with its thoughts alone.
Researchers have long been working to put the brain in direct communication with machines. The hope is one day brain-machine interfaces will allow paralyzed people to operate advanced prosthetics in a natural way. Recent demonstrations have seen animals and humans controlling ever more complex devices.
But the experiments at the University of Pittsburgh, led by Dr. Andrew Schwartz, a professor of neurobiology, appear to involve an unprecedented degree of complexity in terms of the robotic arm, the level of control, and the difficulty of the manipulations demonstrated. Watch:
The video above shows the experiment. Note the monkey on the right side of the screen. It uses its right arm to tap a button. (Its left arm is gently restrained inside a tube.) This triggers the robotic manipulator labeled DENSO [left side of the screen] to position a black knob at an arbitrary point in space. The monkey then controls its articulated robotic arm to grasp the knob.
After gently touching the knob, the monkey places its mouth on a straw: it then gets a drink reward. (Actually, the animal places its mouth on the straw before even touching the knob; that's because it has learned, from repetition, that it's about to get the reward.) After that, both robotic arms reset. Again, the monkey taps the button, waits for the knob's new position, and readily and precisely moves its robotic arm to get a drink.
In this experiment, the monkey received two brain implants: one in the hand area and another in the arm area of its motor cortex. The implants monitor the firing of motor neurons and send this data to a computer, which translates the patterns into commands for the robotic arm.
In a previous study two years ago, Dr. Schwartz and his team taught a macaque to control a simpler mechanical arm to feed itself. This was a four-degrees-of-freedom arm with shoulder joints, an elbow, and a simple gripper.
Now the researchers have added three more degrees of freedom by adding an articulated wrist, which can perform roll, pitch and yaw movements. And the arm itself was replaced by a larger and nimbler manipulator. Although the video doesn't show it, the monkey can not only touch the knob but also precisely turn it by rotating the mechanical wrist.
Dr. Schwartz was kind enough to share this much with us, but he says more details will have to wait until he and his colleagues publish their results. We'll be waiting.
Photo and video: Dr. Andrew Schwartz/University of Pittsburgh
In what may be (but probably isn’t) just a coincidence, a third telepresence robot has made a (pre) commercial appearance in as many weeks. This robot is called Vgo, and… Well, it does telepresence. Stop me if you’ve heard this before, but you get on your computer on one end, connect to the robot, and then drive it around while looking through its cameras. Sensors keep you from running into stuff or falling down stairs, and it’ll run all day on one battery charge. The biggest news, at this point, is that the Vgo is only supposed to cost $5000. Plus a mandatory support contract of $1200 a year. So, $6000.
The Boston Globe has a nice piece on Vgo… There aren’t many more technical details, but I did find this interesting:
Two analysts I spoke with differed on the potential for robotic videoconferencing. Rob Enderle, a technology analyst at the Enderle Group who has written about the slow spread of traditional videoconferencing systems, said that “the closer we get to simulating being there, the better an alternative to travel it will become.’’
But Dan Kara, president of the publishing company Robotics Trends in Framingham, said, “I’m not quite sold on mobile telepresence. How is it that much better than having someone at the remote site carry around a netbook computer with a free copy of Skype on it?’’
The whole minion+laptop+Skype thing is exactly the point we made back when Anybots’ QA was introduced at CES for $30k. Obviously, a telepresence robot is much better than minion+laptop+Skype, but the question is, is it really that much better in terms of cost effectiveness? At the $6k price point, perhaps. Or maybe that’s not the question… Maybe the question should be, how much hardware is required to simulate being somewhere else to the extent that is necessary to make paying for a robotic telepresence solution a practical idea? I don’t have the answer, but hopefully the consumer market will, now that there are (or soon will be) three different telepresence robots available for people to purchase.
UPDATE: Some readers argued that the APOBS, or Anti-Personnel Obstacle Breaching System, developed in a joint program of the U.S. Army and Navy, is not, technically, a weapon, because it's not an anti-personnel system but rather a system used against obstacles. Perry Villanueva, the project engineer for the APOBS program on the Army side, says the APOBS "is not a weapon in the traditional sense, but it is a weapon." Other readers wondered how the rocket compensates for things like wind. Villanueva says that is more of an operational issue. "With high winds it is up to the soldier to position it so it will have a high probability of landing on its target."
iRobot released today new video of its Warrior robot, a beefed-up version of the more well-known PackBot, demonstrating use of the APOBS, or Anti-Personnel Obstacle Breaching System, an explosive line charge towed by a rocket, with a small parachute holding back the end of the line. The APOBS, iRobot says, is designed for "deliberate breaching of anti-personnel minefields and multi-strand wire obstacles." It can clear a path 45 meters long and 0.6 meters wide.
Although it may concern those who don't like the arming of robots, it makes great eye candy for those who like robots, rockets, and explosions.
Now, let me say this: I am neither condoning nor condemning the weaponization of robots, just stating the facts that I am aware of.
In early 2009 a handful of defense related companies came to Thailand to demonstrate their latest war toys to the local generals. One of those companies was iRobot, and as I have many friends who work for iRobot and I was living in Bangkok at that time, I got to meet up with them to see one of the toys they brought: a Warrior.
At the time, the Warrior hardware was complete, designed to carry 150 pounds, but I've seen it lift people standing on it. Unfortunately, and understandably, many of my questions about it were answered with "we aren't sure we are allowed to answer that." I couldn't get an answer as to how much it would cost, but I was given the impression that it's more than $100,000 per unit.
Back in the day, the founders of iRobot had been against the weaponization of robots. Perhaps business and financial pressures are pushing the boundaries. Indeed, the military market is becoming ever more important, according to the company's first quarter results. Finances were very tight in 2009, so iRobot probably sees military systems as a market they'll have to explore and expand.
Updated by Erico Guizzo, June 1, 2010 : Added details on APOBS; edited comments on iRobot financials and weaponized robots. June 2: Added details on demonstration participants, date, and place. June 3: Added more details on APOBS.
Every once in a while, we get to see a video of a robot doing something that makes us think "OMG WTF THAT’S WICKED CRAZY IMPOSSIBLE!!!" And then, we remember that crazy stuff is entirely possible, because we’re talking about robots, and we have to stop thinking about what is and is not possible in terms of human capabilities.
This is one of those videos:
I don’t have much more info for you than what’s in the video, unfortunately, but it does look like these maneuvers (while obviously autonomous) are currently restricted to an area with a whoooole bunch of sensors that can tell the robot where it is with an accuracy (and frequency) that’s probably pretty impressive.
It's graduation season, and yesterday Willow Garage, a start-up dedicated to accelerating the development of personal robots, sent its first graduation class of PR2s off into the world. These 11 robots are heading out to universities and labs in Germany, Japan, Belgium, and the United States, where they will help researchers figure out how robots can assist the elderly and the autistic, navigate buildings and open doors, and help people do house chores, to name just a few of the many projects in the works. At the graduation party in Menlo Park, Calif., some of the researchers told IEEE Spectrum about their plans for these robots. And then it was time to celebrate.
And here's Willow Garage showing off the PR2 at a pre-party press conference. The video was recorded by Spectrum's Erico Guizzo, who was embodied as a Texai, a telepresence robot also created by Willow:
I couldn't make it to Willow Garage's PR2 robot launch party last night, so I went as a robot.
While some 400 people dragged their physical bodies to the event in Menlo Park, Calif., I sat in my living room in Brooklyn, N.Y., and uploaded myself into a robot surrogate.
Using this telepresence robot, called Texai, I was able to move around, see and talk to Willowites and guests, and sip WD-40 cocktails. Just kiddin'. No drinks for robots.
Two Willow engineers built the first Texai prototype just for fun, using spare parts they found in the office. The robot proved so useful it became an official project at Willow, which has built 25 of them.
But the star of the night, and the reason for the party, was another robot, Willow's PR2. Or more precisely, the 11 PR2s that Willow is giving away to institutions all over the world to speed up research in personal robotics.
The PR2 is a mobile robot with advanced vision and manipulation capabilities. Each costs several hundred thousand dollars. But what makes the robot stand out is its software: the Robot Operating System, or ROS, a powerful, open source robotics platform that Willow is building.
Eric Berger (left) and Keenan Wyrobek of Willow Garage show off the PR2 robot. I attended the event via a telepresence robot (that's my face on the bottom left corner).
My colleague Tekla Perry, who was also at the event (in her physical body), interviewed several PR2 recipients and will be posting videos.
For me the most interesting part was being a Texai for a night.
The robot's head is a standard flat-screen monitor, fixed atop a long metal pole. The Texai uses a wheel system similar to the PR2's. And it also runs ROS, which handles the motor controllers and teleoperation functions.
People I talked to via the robot really wanted to know how the driving works. The Texai uses Skype to establish a two-way video link, and a Web page shows a simple, intuitive control interface [below].
You just use the mouse to hold and drag a little red ball and the robot moves. You can also make the head camera point in different directions, or switch to an auxiliary camera that shows the robot's wheels, to help while navigating through furniture and feet.
Learning how to drive is easy. But safety first! Willow makes new Texai users watch a video showing all the things you should not do with the robot -- drive down a stairway, let children ride on it, stick a screwdriver into its body.
At first my driving was in grandma-mode. But after a few minutes I felt comfortable to drive faster and fearless. You can move in any direction, slowly or rapidly, as well as rotate on your vertical axis.
The robot has a plastic bumper, so it won't damage walls, furniture, or a person's leg, for that matter. I did manage, though, to get myself stuck against a wall.
"May I help you?" said Sanford Dickert, my driving instructor and escort at Willow [see photo at the beginning of this post]. Yes, please! He nudged me -- well, the robot -- and off I went.
I headed out to the EE lab to talk to Dallas Goecker, a Willow electrical engineer living in Indiana who, along with Curt Meyers, built the first Texai prototype. Goecker, as he does every workday, was present as a Texai.
So there we were: Two Texai talking to each other screen to screen.
Dallas Goecker, Texai co-creator, and I (inset, bottom left) meet face to face -- or screen to screen.
Goecker told me that being a robot became so natural for him that he sometimes can't recall whether he did something -- a discussion with a coworker, say -- as a person or as a robot.
So what is WIllow going to do with their 25 Texai? They're not selling them. So far they're doing some field tests at undisclosed sites and collecting feedback.
For a company focused on open source projects, I find they're a bit secretive about the Texai. My guess is the robot has commercial possibilities that they want to explore. Especially when you have a Google CEO showing it off at parties.
Or maybe they'll just give the robots away for free.
After the press conference, the party was to continue at a tent outside the building. I was told there was just one robot for reporters. John Markoff was in it and he was not getting out. Damn you New York Times!
Oh, well. I hung out inside with other guests and my Texai brothers. It was fun. The highlight was meeting people I'd been spoken via e-mail or on Twitter but had never met in person: BotJunkie's Evan Ackerman, GetRobot's Noriko Kageki, and Hizook's Travis Deyle -- some of the world's top robotics bloggers!
I even met some celebrities. As a huge MythBusters fan, it was great to chat with Tory Belleci, who for some reason wouldn't stop laughing at me, or the robot, or both [below].
My robotic existence wasn't perfect. More than once people had their backs facing me, though unintentionally, thinking I was just a piece of high-tech furniture. Other people felt clearly uncomfortable with a talking monitor and pretended I wasn't there.
Sometimes I couldn't hear people and vice versa. Twice I lost connection and had to log on again. And once my video feed froze and my face, I was later told, became a Francis Bacon portrait.
But overall it was a great experience. In the future, I see no reason why people wouldn't rely heavily on telepresence robots to attend meetings, interact with coworkers, and -- why not -- go partying.