Thursday, November 18, 2004

Google Scholar - a citation search engine

Google Scholar
Google Scholar enables you to search specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research. Use Google Scholar to find articles from a wide variety of academic publishers, professional societies, preprint repositories and universities, as well as scholarly articles available across the web.

Just as with Google Web Search, Google Scholar orders your search results by how relevant they are to your query, so the most useful references should appear at the top of the page. This relevance ranking takes into account the full text of each article as well as the article's author, the publication in which the article appeared and how often it has been cited in scholarly literature. Google Scholar also automatically analyzes and extracts citations and presents them as separate results, even if the documents they refer to are not online. This means your search results may include citations of older works and seminal articles that appear only in books or other offline publications.

Please let us know if you have suggestions, questions or comments about Google Scholar. We recognize the debt we owe to all those in academia whose work has made Google itself a reality and we hope to make Google Scholar as useful to this community as possible. We believe everyone should have a chance to stand on the shoulders of giants.

Shades of Dickson's encyclopedia, or the Memex of Vannevar. Searching here for a medical condition returns very different items than a standard google search. I look forward to comparisons with PubMed results. This is very intriguing.

Wednesday, November 17, 2004

HandBrake DVD Ripper

HandBrake homepage

External hard drive enclosures: Next up is video out

Gizmodo : SigmaTek X-Bay: "I bet it won't be too long before all external hard drive enclosures come with a commodity MPEG-4 decoder chip and video out hardware built right in."

Dan's Data does a terrific review of PC power strips and surge suppressors

Power struggle

Dan's Data is without equal. Here he tackles surge suppressors. He puts in one place everything I've picked up over many years, and then adds much more. His discussions always remind me of how much we lost when BYTE went under.

We have 3 PCs and 1-2 laptops in our home, not to mention thousands of dollars of other voltage sensitive gizmos. I like the idea of having an electrician install a whopping big fusebox conditioner; OTOH it may be less trouble to buy $50 suppressors and replace them every year. I wish Dan would provide some examples of vendors he likes.
...No ordinary cheap powerboard ("cheap" definitely includes "$US100") actually provides very good protection from line current gremlins...Cheap surge filters are all based around components called Metal-Oxide Varistors (MOVs). MOVs pass current only when the voltage across them is above a set value, and they react to overcurrent in microseconds. A circuit breaker or fuse can take tens of milliseconds to trip or blow; that's much too slow for spike suppression.

Unfortunately, MOVs will only work a few times, at best. The more work they have to do, the closer to death they come...Better surge/spike boards are meant to tell you when their MOV's died via a little light or even a buzzer, but they commonly, actually, don't. A surge/spike filter that's been in use for some years and still reports its MOV as perfectly healthy is, probably, lying.

Better surge suppressors use two other kinds of spike-sinking component. Gas arrestor tubes are much tougher than MOVs, but respond too slowly to be useful for many applications, including computer protection. But they're present in better power filters because they can handle the load of a really big surge, after some other component has (possibly) bravely given its life to intercept the first several microseconds of overvoltage.

And then there are Silicon Avalanche Diodes (SADs), which are between gas tubes and MOVs in toughness, but as fast as a MOV. They're more expensive, though, which is why cheap surge/spike filters never contain them.

The best surge/spike suppressors gas arrestor tubes and SADs, and possibly MOVs as well. Proper "power conditioners" go on to include a great big heavy iron transformer, whose 50Hz resonance (60Hz, in countries that use that mains frequency) and enormous inductance blocks surges and spikes quite well too. This makes the power filter large and heavy and easily as expensive as a mid-range Uninterruptible Power Supply (UPS), but if there's an aluminium smelter down the road from you, this is the kind of filter you want. Rather than faff around buying tons of flaky powerboard filters for all of your electrical outlets, you should get an electrician to install one giant power conditioner at your fusebox; now, the whole house should be bulletproof.

... The take-home message from all of this is that quality power filtering isn't cheap. Fortunately, though, most people here in Australia don't need quality power filtering. To Aussies, I therefore say: Go ahead and buy dirt cheap no-CEW filter-boards, and be merry.

Tuesday, November 16, 2004

A fairly significant limitation to SMB filesharing for OS X

MacInTouch Home Page
[Jann Linder] Samba limits filenames to 26 characters. Since Mac OS X now correctly displays Windows and Samba servers in the Networks file window, users may inadvertently utilize the SMB method of logging on to Mac OS X servers from Mac OS X clients; this prevents them from seeing any files with names longer than 26 chars and anything they attempt to save this way will be corrupted in the filename to a shorter version - if it allows them to save at all.
The only way to tell if you are using the Mac OS X file-sharing vs the Mac OS X Samba windows file sharing is the fact that you will have a login box which asks for 'SMB/CIFS filesystem authentication', and it will ask for 3 pieces of information: A Workgroup/Domain, a Username and a Password. If this is the case, then filenames are limited to 26 chars and you cannot see longer filenames.

I'll have to test this! Since NTFS supports much longer file names I never thought OS X SMB sharing would truncate filenames. I find this hard to believe.

AirPort Extreme Base Station Firmware Upgrade (5.5)

Apple - Support - Downloads - AirPort Extreme Firmware 5.5 for Mac OS X: "AirPort Extreme Firmware 5.5 for Mac OS X"
Pretty extensive list of changes. I'll wait to see what the bugs are.

Nice description of digital camera dynamic range

TidBITS: How to Buy a Digital Camera
For pictorial photography, dynamic range usually matters more than resolution. It doesn't matter if the sensor is able to resolve fine detail on an object if you cannot see the object at all because it is buried in shadow. You can do a quick-and-dirty test of dynamic range even in a camera shop by systematically underexposing photos of a photographic grey scale. I found the dynamic range of the SD-10 to be remarkable. If highlights are correctly exposed, shadows can be 10 to 11 stops darker yet still retain some coarse detail. The pair of screenshots (linked below) from Sigma's PhotoPro software show how easily and effectively this detail can be extracted. This photo was exposed perfectly for the highlights. The dark version shows a normal dynamic range, about what a colour slide would have shown. The light version shows additional detail in the shadows that was recorded by the sensor and brought out by the Tonal Adjustment sliders.

...(Note that with a digital camera, increasing the "ISO" speed does not make the sensor more sensitive, it amplifies the signal and, at the same time, it amplifies the noise. "ISO" 100 is normal for most cameras and speeds up to 1600 are commonly available, but any speed over 400 is not likely to look very good.)

Some cameras offer a choice of metering modes - spot, segment, averaging - so you can choose the one most likely to be accurate for the picture you are about to take. This is the sort of silly featuritis that makes so many electronic devices difficult to use. There is no point to trying to figure out how to set the meter to read a scene the most accurately, it's as fast and more certain to take a quick test picture and adjust the control that nudges the automatic exposure up or down. Automatic exposure-bracketing is almost as useless: there is rarely reason to bracket exposures when you can identify the correct exposure when you make it. The SD-10 dedicates push-buttons and primary display space to both of these "features."

Something else I can't see worrying about is how the camera reproduces colour. As I explained in "Colour & Computers" in TidBITS-749, this is tantamount to complimenting or castigating an amoeba on its figure. There is even less reason to worry about the colour reproduction of lenses. If a lens tints the image that it projects onto the sensor, the tint will be systematic and slight, and it will be corrected automatically by whatever software converts the raw image into a usable one...

One in a series of hard core digital photography articles printed in Tidbits. I've learned something with each one, and I'm not a complete novice.

There's lots of fine commentary in here. The author is writing about a very high end camera, but the commentary is relevant to every digital camera. I ended up thinking we really need to move away from the anachronisms of film photography and adopt new imaging parameters. The ISO control may be the worst of the bunch.

We're fine with 6 MPixel sensors for all the pictures I'm likely to do. Let's see the focus change (sorry) to dynamic range, image stabilization and light sensitivity. Forget the darned megapixels.