Speeds and Feeds

I'm a big fan of "German engineering"--that combined focus on power and precision that distinguishes the better automobiles designed or manufactured in Germany.

At Frankfurt's International Motor Show, BMW will be showing off two new hybrid cars intended to deliver the full promise of German engineering. This is no small thing because most hybrid cars to date have been lightly built and somewhat underpowered in order to improve fuel economy.

The two new BMWs are more like previous offerings from that company: big, solid cars with lots of power to maintain performance in spite of the weight. They're also real cars, not just prototypes.

Fortunately, I don't need to describe these new cars here; there's a great article by Antuan Goodwin over on CNET's Car Tech blog that does a fine job of that (see "BMW unveiling two big hybrid models at Frankfurt"). What I would like to do instead is to drill down into their respective powertrains, which represent two different solutions to high-performance hybrid design, using images provided by BMW.

The ActiveHybrid X6, due to go on sale in the U.S. later this year, represents one end of the spectrum: higher-power electric motors and a larger battery pack. As the first image shows, the new X6 model has a twin-turbo V8 gas engine with 400 horsepower. Though this is a reasonably efficient engine for its size, it certainly wasn't chosen primarily for its fuel economy.

BMW's ActiveHybrid X6 uses a large NiMH battery pack and a new transmission with two integrated electric motors to augment its 400-horsepower gasoline engine.

(Credit: BMW)

The large NiMH (nickel metal hydride) battery pack is also visible in this view, mounted above the rear drivetrain components and below the floor of the luggage compartment. This battery pack holds 2.4 kWh (kilowatt-hours) of energy; BMW also specifies a "nominal" 1.4 kWh figure, but doesn't explain the difference between total capacity and nominal capacity. I suspect the difference may be related to improving battery lifespan, or perhaps provide some extra storage to ensure that electric braking assist (regenerative braking) is always available. BMW does say that this braking mode can generate as much as 50 kilowatts of power and 0.3 g of deceleration force.

In the following view of the X6's transmission, the electric motors are shown built right into a new transmission that BMW describes as an "electric continuously variable transmission"--the electric motors and three planetary gearsets work together to provide the equivalent of seven gear ratios.

The transmission in the ActiveHybrid X6 has two integrated electric motors totalling 177 horsepower.

(Credit: BMW)

Interestingly, with ratings of 91 and 86 horsepower respectively, the two electric motors could provide a total of 177 horsepower, but the vehicle isn't designed to operate that way. BMW specifies a maximum system output for the ActiveHybrid X6 of 480 horsepower, reflecting a maximum contribution from the electric motors of around 80 horsepower.

Part of the issue here is that the battery pack is rated at a maximum output of 57 kW, roughly 76 horsepower, so there isn't enough electrical power to drive both motors at full power. I expect there are also some issues related to heat and torque, but BMW hasn't offered a full explanation of this limitation.

It's also interesting to note that while the new X6 supports a pure electric drive operating mode, it's only good up to 37 mph and 1.6 miles. This figure is well below the energy capacity of the battery pack, probably reflecting more limitations imposed in the name of long-term reliability.

The ActiveHybrid 7, a hybrid version of BMW's 7-series luxury sedan due out in the spring of 2010, takes a very different approach. It has only a small electric motor positioned between the engine and transmission, and it comes with only a small lithium-ion battery pack. The following figure shows that the battery pack is located to the side of the trunk, leaving plenty of space for golf bags. (BMW says that four standard bags will still fit, which I suppose is a critical specification for 7-series customers.)

The ActiveHybrid 7 is powered by a 440-horsepower gasoline engine and a small 20-horsepower electric motor with a lithium-ion battery pack.

(Credit: BMW)

Zooming into the transmission in the following picture, we can see the pancake-style electric motor in front of what appears to be a fairly conventional 8-speed automatic transmission. In its press release, BMW does emphasize that this is a new transmission design "specifically tailored to the demands of hybrid technology," but the release doesn't explain how this gearbox differs from the 8-speed automatics on previous BMW cars.

The ActiveHybrid 7's electric motor is tucked away between the gas engine and a conventional 8-speed automatic transmission.

(Credit: BMW)

The new 7's electric motor produces a mere 15 kilowatts, roughly 20 horsepower. Together with the gas engine, the vehicle's maximum output is rated at 455 horsepower. The electric motor also functions as a starter motor for the gas engine and a generator to charge the two batteries on the car: a conventional 12V lead-acid battery and the 120V lithium-ion pack in the trunk.

The latter is a small pack storing only 400 watt-hours of energy--that's about like eight average laptop batteries. BMW doesn't mention whether the new 7 can run solely on the electric motor, but I doubt it; 20 horsepower probably isn't enough for that. Certainly the range would be negligible given the low battery capacity.

Instead, BMW describes the value of the electric motor in terms of two uses: first, it's powerful enough to restart the gas engine almost instantly (in less than one rotation of the crankshaft) so the engine can be shut down at stoplights, just as the Toyota Prius does. Second, the electric motor provides supplemental power while the gas engine is running, thus improving overall fuel efficiency. Since the battery can be charged by recovering braking energy, the power from the electric motor is often free.

BMW says the hybrid systems in the ActiveHybrid 7 were developed jointly with Daimler, maker of Mercedes automobiles. This partnership also led to some Mercedes models, and indeed, Mercedes has also introduced hybrids with powertrains similar to that of the ActiveHybrid X6. (Mercedes is announcing a new S500 hybrid in Frankfurt but didn't provide such nice pictures, so I didn't include it in this post.)

Both of these approaches will need to be developed substantially before they can reduce the total cost of owning and operating a motor vehicle. But it's clear that BMW, having waited this long to get into the hybrid car business, is giving its customers two very different choices. What the company does in the future will probably depend on how its customers respond.

In a corporate blog post this week, Microsoft Vice President Horacio Gutierrez promoted the idea of a "harmonized, global patent system," in which all the nations adopt common standards for processing and approving patent applications.

Properly done, patents approved in one country could become enforceable in other countries, as is the case with copyrights under the terms of the Berne Convention.

I really have no problem with harmonization if it is properly done, but I think it would be tremendously difficult to achieve good results. The reality of patent protection is radically different from that of copyrights because patents are allowed based on the merits of the application; someone has to make a judgment call.

Would nations be able to compete for patenting fees on the basis of their approval rate? After all, who could say whether I invented a new audio calibration standard here in Cupertino--or Costa Rica, if I just happened to visit a patent agent while on holiday there? Even if this wasn't allowed, I expect all nations would begin to relax their standards in order to give their local inventors an edge in the global marketplace--a classic "race to the bottom."

Or would there be just one international patent bureau, perhaps run as an agency of the United Nations? I shudder to think how that would turn out, with the General Assembly dominated by smaller nations with little vested interest in patent protection.

Unfortunately, Gutierrez takes the latter position:

In today's world of universal connectivity, global business and collaborative innovation, it is time for a world patent that is derived from a single patent application, examined and prosecuted by a single examining authority and litigated before a single judicial body.

Not only does he want an international patent bureau, he wants to create a new international court system with global enforcement powers. The potential for abuse here is truly staggering.

But as objectionable as I find that proposal, my real issue with Gutierrez's post is that it's completely irrelevant to the real problems with the worldwide patent system.

Gutierrez summarizes:

Big challenges certainly confront the global patent system: Escalating patent application backlogs; lengthening pendency periods; increasing costs of patent prosecution; dubious patent quality due to the global explosion of prior art and the time allowed to examine applications; and examination inefficiency due to duplication of work by multiple offices.

Removing the duplication would help a little. About half of U.S. patents go to non-resident inventors. That fraction is increasing, and it's already larger in most other countries because of the stronger emphasis on innovation in U.S. companies. Letting inventors go through the process just once, in their own countries, would eliminate the duplication. But again, I think this approach would create more problems than it solves.

In any event, a factor of two here or there is not going to solve the fundamental problem of patent quality. The high percentage of bad patents in the system--and believe me, I can personally testify to how many bad patents are out there--undermines the whole system.

I've been thinking about this problem for over 20 years now, and I have some suggestions:

Problem statements. All patent applications should include a statement of the specific problem(s) the claimed invention is intended to solve. These problem statements should be published immediately and anonymously, along with whatever prior-art references have been disclosed--but no details of the invention itself. The problem statements and prior-art references would be taken as narrowing the scope of the invention. The public would then be free to point to known solutions, or even submit new ones, which would create a presumption of obviousness if they happen to coincide with the filed claims.

Claim standardization. One social benefit of the patent system is to publish inventions so that others may use them, either immediately if a license is made available, or after the patent expires. A published patent may also serve as the foundation of further inventive work. But patents are difficult for humans to understand and are practically immune to reliable machine analysis and searching. I think patent claims should use a standardized grammar and vocabulary that eliminates ambiguity and precisely identifies the scope of the invention. Although defining these new standards would be a difficult and lengthy process, the rewards would be tremendous.

Examination fees. As an inventor myself it pains me to say this, but examination fees must cover the actual costs of examination. That means charging enough to let the patent office hire enough qualified examiners to handle applications as quickly as they come in, rather than letting a backlog develop. Published problem statements and standardized claims will help a lot, higher fees may cut down on bogus patent filings, and we'd all like to see the patent office managed better. But ultimately, the system has to support itself.

No triple damages. U.S. law provides for triple damages when someone "knowingly, deliberately, intentionally, willfully, or wantonly" infringes a patent. But these damages are routinely awarded whenever there is evidence that an infringer was aware of a patent, even if the knowledge played no role in product development or there was truly some reasonable disagreement as to whether the patent was relevant. As a result, this law discourages study of existing patents, which is directly contrary to the constitutional purpose of the patent system. Knowledge alone is not a bad thing; we shouldn't penalize it.

I'm sure there are many other good ideas out there for improving the U.S. patent system. We need to talk about them, and we need to find solutions to our own problems before we even start thinking about globalization.

Editors' note: A bold claim this week by General Motors, that its forthcoming Chevy Volt electric car would get 230 miles per gallon, prompted us to do some musing on a possible historical precedent.

For Release the 11th of August, AD 1909

Durant "Chevrolet" Expects 230 mpb in Town Jaunts

WARREN, Mich. - William Durant, chairman of the General Motors Company, announced to-day that his new "Chevrolet" gasoline automobile, named after famed racing-car driver Louis Chevrolet, will boast almost six times the fuel efficiency of a comparable horse-drawn carriage.

Durant attributed this remarkable figure to a modern scientific method developed by the Equine Provisioning Agency of the Federal government in the District of Columbia.

"Whereas the EPA has determined that a ten-hundredweight carriage horse pulling a brougham with two passengers will consume one forty-pound bale of alfalfa hay for a day's travel of forty miles, this marvelous new automobile can travel some 230 miles on the same weight of gasoline."

And this despite an engine with the power of some 40 horses!

No representative of the EPA was present at this extraordinary news conference to elaborate on this new "miles per bale" standard, but Durant assured the attending members of the fourth estate that m.p.b. figures will become the gold standard of automobile efficiency measurements for all time.

One curmudgeonly figure at the back of the hall, however, was heard to complain that the 230 m.p.b. estimate was "an abstract number," and that one might just as well claim that any gasoline automobile can travel an "infinite" number of miles on a bale of hay. With a nod from Durant, a burly Pinkerton agent escorted this disagreeable nay-sayer out of the hall, and he was not heard from again.

The new "Chevrolet" will go on sale within two-score fortnights at the price of $2,150. Durant did not announce which of the General Motors brands will have the honor of selling the new motor-car. Though only society's elite--perhaps the lordly Harvardmen who so confidently shepherd the New York Stock Exchange--will have the pleasure of driving this magnificent machine, those of ordinary means may at least be proud that American know-how is behind such a glorious accomplishment.

A few weeks ago, I wrote about Jerry Lewis' role in the development of "video assist" technology, the use of video technology to support film making (see "Jerry Lewis and the elusive Video Assist patent"). Lewis was credited as the inventor of video assist during the Academy Awards telecast in February, and more specifically, was said to hold a patent on the technology.

I looked for this patent because I thought it would be interesting to write about it here, but I didn't find it. After I contacted the U.S. Patent and Trademark Office for help with the story, it looked too. The bottom line is that there is no such patent.

This illustration, from an article written by Jim Songer for American Cinematographer magazine, shows a Panavision camera with the video assist subsystem integrated into the loading door.

(Credit: Jim Songer and Video West)

It turns out that video assist goes back to well before 1956, when Lewis claims to have invented it--as he did in a 2008 interview with Peter Bogdanovich.

Thanks to a commenter on my original post, plus some long discussions with Jim Songer, an engineer who made substantial contributions to video assist in the 1960s, I have tracked down what may be the earliest patents on video-assist technology.

But before I get into those patents, let me describe the elements of video assist technology in a little more detail.

First, video assist relates primarily to motion picture production. As the name suggests, the purpose of the video is to assist the production by allowing the director, actors, and other crew members to review what's being filmed. This can be done live, or if video recording is used, the video can be reviewed after the shot.

The ultimate implementation of video assist requires simultaneous film and video recording of the same scene with the greatest possible quality and convenience. Accordingly, both film and video recording should be accomplished with what amounts to one camera, which should meet all the other requirements for motion-picture principal photography, use the same viewfinder and all of the same controls, and work with the same lenses and lighting.

There can still be considerable value to a system that doesn't meet all these requirements. Indeed, the earliest video-assist systems were very simple.

US Patent 2,420,197 by Adolph H. Rosenthal, issued in 1947 with a 1944 filing date, describes combining film and video cameras on ... Read more

The annual Maker Faire, which lies somewhere between San Francisco's counterculture tradition and Silicon Valley's materialism, is set for this weekend in San Mateo, Calif.

Now in its fourth year, the event is organized by Make magazine and showcases the work of people who build everything from wooden bicycles to life-size robotic critters.

I've been making some fun things myself since I bought a small milling machine awhile back. Here's a titanium adapter I made to attach a small commercial USB flash drive to my keychain:

A USB flash drive (right) with keychain adapters milled out of titanium.

(Credit: Peter N. Glaskowsky)

The assembled titanium-reinforced drive fits into any USB jack.

(Credit: Peter N. Glaskowsky)

Not long ago I found some blocks of aluminum bar stock at HSC Electronics in Santa Clara and had the idea to turn one into a stand for my iPhone. I had the standard iPhone dock, but it's not very stable, and I wanted something better. I realized I could mill a pocket into the aluminum block for the dock, plus create a face for the iPhone to lean against. The result was nice, stable stand.

I decided to preserve the original finish on the block for an industrial look:

The first-generation iPhone stand, made from a cylindrical block of aluminum and Apple's iPhone dock.

(Credit: Peter N. Glaskowsky)

After making that first one, I thought of some other ways to apply the same idea:

Another design. The Apple iPhone stand slots into the recess at the bottom, between the "wings."

(Credit: Peter N. Glaskowsky)

Another design, polished up a little.

(Credit: Peter N. Glaskowsky)

This one's my favorite so far:

Yet another design, also with wings.

(Credit: Peter N. Glaskowsky)

A side view.

(Credit: Peter N. Glaskowsky)

There's always something at the Maker Faire to inspire more projects. Come back to Speeds & Feeds next week for a review of the event.

If you have an iPhone 3G configured for use in English, open up a new Note or Mail message and type the word "neat."

Your finger missed the "t"--didn't it? You typed "r" instead, for "near." That's OK. Backspace over the word and try again.

Oops. Missed it again, didn't you? Never mind, try again.

Apple's iPhone 3G

(Credit: Apple)

That "t" sure is difficult to hit, isn't it? Well, you can always try the tap-hold-drag method of typing. Backspace over the word again, type "nea", then tap the T and as soon as you see the letter appear above your finger (it'll probably be an "R" again), drag your finger around the keyboard.

Pretty amazing, huh? Any letter but "t" can be typed in. That's right. Some iPhones simply won't let you type the word "neat" without using the backspace.

The problem isn't limited to this word or this character. I discovered the problem for myself recently when trying to enter the name of a restaurant ("Quattro") into a new calendar event. Further experimentation revealed many other impossible sequences.

I'm used to mistyping things on my iPhone; errors are inevitable with such a small keyboard and no physical feedback, and I tend to just blaze along as fast as my fingers will go. But occasionally, it seems to me that I hit the key I wanted but get something else instead.

I knew I hadn't missed the "t" because I was typing "Quattro" relatively slowly. I backed up, typed the word again even more carefully, and suddenly realized that some of my typing errors aren't my errors at all!

After fiddling around with my phone for a while, I realized that the iPhone virtual keyboard code attempts to predict what key(s) you'll type next and prefers the more likely keys over the less likely keys.

In extreme cases, when the code thinks a certain letter is pretty much impossible, it'll block that letter entirely.

This works well when you're typing a word like "fish" and you type "fisj" instead. Nobody likes getting fisj when they are hoping for fish, right?

I don't really understand all of the decisions built into the code. For example, "abcf" is not allowed, but any other final letter is fine. Is this because "abc" is most commonly followed by "d" and, thus, "f" is just too close for comfort? But then why isn't "abcs" blocked?

But the real problem is that sometimes--as with the word "neat"--this code doesn't anticipate all the legitimate letter choices.

Oddly, it isn't that the iPhone doesn't like the word "neat." If you accidentally type "neay," it'll suggest that you really meant "neat." So the character-predicting code must be separate from the dictionary.

I also established that there are some places where this character prediction routine doesn't operate, such as when you're typing into password dialogs and short text boxes in Web pages. But when typing into large text boxes, like the Comment boxes on these blog posts, the "neat" problem returns.

I looked around online after discovering the problem with "Quattro" and found very few references to the problem. However, one page on the Mobile Computer magazine site ("Is the iPhone's predictive text too clever for its own good?") has not only an explanation but a video of the problem. That's also where I learned about "neat," which is the worst case I've seen so far--a perfectly good, common word that you just can't type into an iPhone.

I figure this issue deserves wider attention, hence this post. I've also asked a few people I know with iPhones to test the problem. Two people with 3G models saw exactly the same behavior. One person with a first-generation model didn't. If your phone doesn't behave as I've described here, add a comment below to let me know.

I saw the new Star Trek movie in its limited release on May 7, and enjoyed it a lot (although I did think giving the Enterprise the new hull number NCC-90210 was a bit much).

Anyway, the movie includes scenes set in Iowa, which got me thinking about what life is like for the average person in the Federation of Planets. I think it probably isn't very different from life here on our Earth.

(Credit: Paramount Pictures)

For example, we don't have warp drives, transporters, food replicators, or phasers, but I don't think these are part of the daily life of the average citizen of the Federation either.

In the new movie, I was struck by several scenes in which the technology of the mid-23rd century seemed to be markedly behind our own. I assume these anachronisms were considered essential for consistency with the various Star Trek television series, but I think this movie could have provided a good opportunity to retcon these awkward precedents and make Star Trek seem more futuristic to today's audiences.

But no. Today we have cellphones the size of Zippo lighters, whereas in 250 years, communicators-- even for intraship communication, as shown in the new movie-- will be larger, and somehow they will lose any kind of display screen.

Indeed, Lt. Uhura sometimes wears the trademark huge circular-finned earpiece from the original series, though most characters get to wear something much more like today's Bluetooth headsets.

In another scene in the movie, a courier delivers a message to a senior Starfleet officer by carrying to him-- likely over a significant distance-- a large electronic clipboard. We've had Short Message Service support on cellphones for over ten years! If you've seen the original Star Trek series, you've seen these clipboards-- Yeoman Rand used to bring them to Captain Kirk on the bridge.

These clipboards-- also known in the Star Trek universe as data slates, or most commonly, Personal Access Display Devices (PADDs)-- shrank over the years; by the 24th century, they were down to the size they are today.

The engineering areas of various Starfleet facilities and even the new Enterprise were even worse; some of those scenes could have been filmed in a 19th-century boiler room (or maybe brewery) with a new coat of paint.

I also noticed a very futuristic forklift truck in the movie, but it turns out that too (the exact product) is an early 21st-century product.

But generally, life in the Federation does seem to be much more relaxed than life on our Earth, and technology presumably plays a role in that, even if it's usually behind the scenes. I wouldn't mind living there.

Actually, there are the occasional planet-shattering alien attacks. I wouldn't like those. Maybe I'd be happier somewhere I can combine 21st-century technology with a mellow 23rd-century lifestyle, like Marin County.

A new Web-based rental service called BookSwim describes itself as Netflix for books.

After checking it out, that seems to be a fair enough summary.

The pricing doesn't seem to be quite as good a deal as Netflix; the fees are slightly higher and the average price of books is somewhat lower than for movies. But it's in the ballpark.

For example, BookSwim offers a subscription with three books out at a time for $19.98 per month. BookSwim covers shipping both ways via U.S. Postal Service media mail, though books over two pounds do carry an extra fee based on the actual difference in postage.

This is not too far away from the three-DVD subscription from Netflix for $16.99 per month, also with free shipping.

BookSwim is aimed at high-volume readers; its plans go up to 11 books at a time for $39.94 per month.

BookSwim has an additional requirement that is probably a consequence of the media mail rate schedule. Customers must return multiple books at a time, depending on the service plan: 2 or 3 for the 3-book subscription, 4 or more for the 11-book subscription. Then BookSwim ships multiple books at a time to the customer.

I was curious about the weights of books, so I grabbed a few Larry Niven/Jerry Pournelle novels off my recently read stack and weighed them on my kitchen scale:

Fallen Angels (with Michael Flynn) in paperback: 0.48 pounds

Inferno in trade paperback: 0.51 pounds

Escape from Hell in hardcover: 1.27 pounds

It looks like paperbacks will never exceed the two-pound mark. However, I can see larger hardcovers getting into excess-weight fees, especially technical nonfiction:

GPU Gems 3 by Hubert Nguyen: 3.8 pounds

Physically Based Rendering by Matt Pharr and Greg Humphreys: 5.77 pounds

Fortunately, the fees would be low: only an extra $1.40 each way for the latter book based on the published media mail rates, cheap compared with its current $74.36 price on Amazon.com.

One might think about using BookSwim to rent textbooks. At $120 for four months' use of seven textbooks, this would be a great idea...except they thought of it first, and they don't do that. BookSwim has a separate service to help students find textbooks, but it's nothing like the regular subscriptions; mostly it consists of referring customers to BookRenter.com, where textbooks rent for a large fraction of their retail price.

In its online media kit, BookSwim addresses the obvious question: why not just go to a library?

The company's answer includes these main points: no late fees, 24-hour browsing, a wider selection, less waiting for popular titles, and no need to leave home.

I'm not persuaded by all of these reasons. I don't believe BookSwim's selection is as wide as a major city library. The Martin Luther King Jr. Library here in San Jose claims a collection of over 1.5 million items. And its catalog can be searched online, like most libraries these days. BookSwim's selling points probably mean more to customers who don't have a big library nearby.

I suspect the waiting-list and convenience issues will favor one side or the other, depending on the customer and the books they're reading.

The page also says this about BookSwim's selection: "Can't find a book on BookSwim.com? Let us know and we'll buy it!"

If I really believed that was true without restriction, I'd sign up in a hurry, since there are many more technical books I'd love to read that are way out of my price range. Rare books would be another great way to take advantage of this promise, and it would also seem to provide a way to get textbooks through BookSwim. The promise doesn't appear in the company's Terms of Use agreement, however, so it probably isn't meant to be taken literally.

All in all, BookSwim seems like a pretty good deal for avid readers. It seems to make the most sense for people who like to read popular, new hardcover books, especially if they read a lot, don't care to keep all the books they read, and prefer to use their spare time for reading rather than running to the library.

That summary may sound like a narrow market, but it fits me pretty well, and I think it could make a decent business for BookSwim.

Just a quick heads-up--

Because of the current tough economic times, the non-profit Alameda County Computer Resource Center (ACCRC) is auctioning off its collection of vintage computers, video-game systems, calculators, and other collectible electronics to fund its other operations, which include job-training programs and refurbishing more modern PCs, which it donates to schools, other non-profits, and disadvantaged individuals.

A Processor Technology Sol-20 microcomputer system in the ACCRC auction.

(Credit: Alameda County Computer Resource Center)

The ACCRC auction is being managed by the Vintage Computer Festival organization in multiple rounds. The second set of systems being auctioned is online now, with a deadline of noon (PST) on Jan. 5; more will follow. VCF proprietor Sellam Ismail says there are "hundreds" of items in the collection, so these auctions will likely continue for some time.

The star of this round is a Processor Technology Sol-20 microcomputer from the late 1970s, along with a matching 8" floppy drive. The Sol-20 is widely regarded as one of the most attractive systems from that time period, with oiled-walnut side panels and blue-enameled sheet metal. I have one of these machines myself.

Also available in this round are several Kaypro machines, a GRiDPad 1900 pen-based computer, a couple of HP calculators (a 41CV and the typewriter-sized HP-85), and several other nice items.

If you're interested in vintage electronics, keep an eye on the auction page. You may find something you want, and your bids will help out a worthy charity.