Wikipedia:Reference desk/Archives/Computing/2006 October 17

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

October 17

PICAXE programming under Ubuntu GNU/Linux

Hi,

So far, I have failed to find any substitute for the Programming Editor available for PICAXE programming on Windows. I tried to run it on Ubuntu with Wine, but it's really garbage.

So... Any substitutes under Ubuntu or rather Linux as a whole? Thanks.

--inky 05:27, 17 October 2006 (UTC)

Um, have a look at gnupic.org to see if there's something suitable for you. --Robert Merkel 06:58, 17 October 2006 (UTC)

Thanks for the response... although the site's a bit confusing...--inky 20:38, 19 October 2006 (UTC)

Hmmm... According to this article, PICAXE is a modified version of PIC chips. Are they compatible? --inky 21:09, 19 October 2006 (UTC)

Converting Google Video to mpg

Say, I want to convert this google video file I downloaded into an mpeg format. How so? — X [Mac Davis] (SUPERDESK|Help me improve)08:58, 17 October 2006 (UTC)

That is not possible, A Google Video file is a closed format. But you can download a Google Video file for a Sony PSP or an Ipod, I think you can convert those files to an other format. Tukkaatje 12:44, 17 October 2006 (UTC)

I don't know if it currently exists, but it should be possible via video capture software. StuRat 13:36, 17 October 2006 (UTC)

Naevius GVI Converter claims to be able to convert GVI files to the standard AVI format, though I know nothing about it and have never used it, so can't vouch for that. Loganberry (Talk) 14:41, 17 October 2006 (UTC)

By using regular screenshots, you can capture and re-encode the video. You can then capture the audio as it goes to your sound card. You'll have to get/write the scripts for that yourself though (since Google Video Player is a VLC fork, it should have an option to disable DX overlays).--Frenchman113 on wheels! 22:22, 17 October 2006 (UTC)

No. The best way to do this is to use something that can play and convert FLV files. For example, mplayer's mencoder can do it. --Kjoonlee 06:45, 19 October 2006 (UTC)

But why convert when you can use mplayer to play the files? --Kjoonlee 06:45, 19 October 2006 (UTC)

VLC and MPlayer can both play FLV files. --Kjoonlee 06:55, 19 October 2006 (UTC)

Does Google rank pages by outgoing links?

I thought Google ranks pages by incoming hyperlinks.

Does the number of outgoing links also affect a page ranking?

What effect does this have on Wikipedia?

As far as I know the basic method involves ranking by incoming links, and it wouldn't make any sense to do it the other way around. I've heard that Wikipedia was granted an especially high rating by Google employees (and I assume many trusted websites are given similar treatment) which may boost articles to the top of the search even when there are few incoming links. I can't say I'm familiar with the methods that page ranking services like Alexa operate on.  freshofftheufoΓΛĿЌ  09:17, 17 October 2006 (UTC)

Yes, I'd say only incoming links (weighted with the credibility of the linking page) have any effect. —Bromskloss 11:56, 17 October 2006 (UTC)

It is my opinion that the age of a website is also used by Google. I've had the same domain name, with an active web page, for many years - long before Google or Lycos or Alta Vista or Yahoo... There are very few sites on the web that link to my website. So, it shouldn't be considered much of anything. But, my site is spidered by Google (and Yahoo and MSN and Ask...) daily. Without the incoming (or outgoing) links to use as a basis for why Google considers my page worth spidering, I'd have to say it is the age of the site. --Kainaw ^(talk) 17:22, 17 October 2006 (UTC)

(As directed at the top of this page, please sign your posts using four tildes ("~~~~").

Automatic page ranking done well is what boosted Google to the top of Internet search engines. The original theory was published, so is no secret. However, any such system can be manipulated, and many folks have a huge financial incentive to do so. Therefore the details of what is done today are constantly changing, and not made public; here's the little Google itself says. Speculation abounds, some better informed than others.

And did it not occur to you to seek an answer to this question by searching the web? --KSmrq^T 04:51, 18 October 2006 (UTC)

And going back to the original question (after a little more reading, and maybe realizing the questioners original intent), the number of outbound links also plays a major role in page ranking, as described by the original page rank algorithm. Basically, any page's relevence to the page rank of another is inversely proportional to the number of outbound links, which obviously helps prevent sites bent on advertising from boosting the ranking of many other sites bent on advertising. So simple yet so wicked cool.  freshofftheufoΓΛĿЌ  06:12, 19 October 2006 (UTC)

Image comparison script

We get a quite a few questions about identifying sources for pictures, and I swear I've read somewhere (popular science or something like that perhaps?) about programs/a program that index internet images (like google images does) and then compare them using some sort of algorithm to find similarities, and find duplicates.

I've found a couple pages boasting similar abilities, but only for small limited sets of images. Does anyone know of such a program?  freshofftheufoΓΛĿЌ  09:12, 17 October 2006 (UTC)

I've discussed just such a program at the Ref Desk before. It's quite difficult, as it would ideally need to be able to deal with the following:

• Different scale images.

• Different image formats.

• Different clipping. For example, a pic should be able to be matched with a close-up of one part of the pic, or two pics which have an area of overlap should be matched.

• Different color schemes, 32 bit, 24 bit, 16 bit. 8 bit, greyscale, and even black and white.

• Different aspect ratios.

• Mirrored or rotated images.

• The most difficult problem, likely requiring some form of artificial intelligence would be to match pics of the same object from different angles.

You could write a program to do all that, but it would take a long time to compare any two pics. If Google were to try to use it to categorize all their pics, the resources required to get this job done would be extreme. StuRat 13:27, 17 October 2006 (UTC)

If you've ever used a tool which implements the SiFT algorithm, you'd be pretty impressed at how good the feature recognition is. (It deals with stretched, squashed, sheared and rotated images, and image parts.) I wouldn't think it entirely out of the realm of possibility. You'd have to have a human on the end of it, but there are algorithms which can cut down tremendously on the amount of human work. grendel|khan 16:07, 17 October 2006 (UTC)

That sounds good, and is basically how I imagined it, though I don't think it should be all as difficult as StuRat makes it out to be. I guess the images would have to be prepared for scanning before they could be included in a search, e.g. by simplifying the image at certain levels, maybe 1/10 detail, 1/3 detail, and 2/3 detail. That would obviously take a lot of space, but storage volume never seems to be a problem anymore (just look at Wikipedi!). It should be relatively easy to compare extremely basic arbitrary shapes with posterized colors, even if rotated. Clipping is a bit of a problem, but I guess most of the searches would/should be for identical or similar pictures that haven't been radically clipped, so at least for now clipping can be ignored. The simplified images would all be scaled to the same size (let's say max dimension 500 pixels) and would be in the same format, so you don't have to worry about that.

There should at least exist a search tool that can find identical images of different dimensions/file formats/colors, maybe I'll try to do that myself when I go back to school.  freshofftheufoΓΛĿЌ  06:00, 19 October 2006 (UTC)

One place this comes up is when I use Google image search to look for pics from a movie. I end up with 10,000 pics of the cover of the DVD and/or promotional poster, and very few of the actual movie, scattered sparsely amongst all those duplicates. StuRat 15:44, 19 October 2006 (UTC)

Yeah, it's probably a very high-priority project for them o'er at Google, to reduce the number of useless image results.  freshofftheufoΓΛĿЌ  04:09, 21 October 2006 (UTC)

WIFI 2-way control with Pocket PC

Hello! I want to be able to control my Pocket PC from my desktop via WiFi. BUT: I also want my Pocket PC to send back images from its camera. Is there any easy way of establishing this 2-way control? The reason I want to do this is to control a robot using beeps emitted from the Pocket PC's headphone socket, but also see where it is going at the same time.

I have tried Microsoft Portrait, but that gives me no control of the Pocket PC. Please can you help me. I have also tried Portrait and MS Remote Command but that is a very slow process. Please can you help me! --212.56.97.238 11:35, 17 October 2006 (UTC)

Best programming tool for beginner

Whats the best free programming environment for a beginner with no programming experience? It should due GUI stuff and create stand alone executables. Cross platform prefered.

What about Lazarus, which is based on the open-source Free Pascal and runs on Win32, Linux, MacOS, FreeBSD...? Lazarus is a clone of Delphi, which is itself based on Pascal. It's still a work-in-progress so may not be stable or complete enough for large projects, but on the basis of a few minutes' playing around with it I think it's quite good enough for learning on - and you also have the advantage that much of the huge volume of Delphi documentation will be applicable to Lazarus too. Loganberry (Talk) 14:38, 17 October 2006 (UTC)

If by environment you mean something broader than IDE, I recommend BASIC. Try FreeBASIC or PowerBASIC. --froth^{T C} 17:15, 17 October 2006 (UTC)

IMHO, a "beginner with no programming experience" should not be worried about GUI "stuff" and cross-platform executables to start with, but with learning programming. It's like asking what's the best driver's education program? It must allow me to drive an F-1 class Ferrari next week. --LarryMac 19:06, 17 October 2006 (UTC)

Yeah, I agree. Although, VB makes it pretty easy to do GUIs, if I remember correctly. Newbie easy. It's a very BAAAAD way to learn though, you should learn the basics first Oskar 23:35, 17 October 2006 (UTC)

Oh yes, VB has ruined many an aspiring programmer's career. Learn it much later if you absolutely must, but otherwise stay the heck away --froth^{T C} 02:08, 18 October 2006 (UTC)

A beginning programmer needs to learn programming, which is an uncommon discipline. See Category:Educational programming languages for a selection of languages intended to help, most of which come with development environments and cross-platform implementations. Notable examples are Logo, Scheme, and ToonTalk, from the MIT tradition, and the Smalltalk family out of Xerox PARC.

Programming requires structured thought, structured action, and structured data. Daily life is not adequate preparation for these demands; in fact, most people give terrible directions and unsound explanations. A mistake in a single character in a program can cause it to fail — a daunting challenge when confronting a program requiring thousands of lines of code. Thus programming includes not only problem definition, method design, and program implementation, but also structured testing, structured diagnosis, and structured correction. A final essential is documentation, especially important in a large project.

Do not be embarrassed to begin with a training environment like Alice; the insights and habits gained there will be more important in the long run than wrestling with the obstacles of a “serious” implementation language like C++. And, paradoxically, the total time to mastery of C++ will likely be shortened by including this learning step. --KSmrq^T 06:57, 18 October 2006 (UTC)

Odd first line on "database" entry page

I think this might be vandalism, but the first line on the entry for "database" reads like a nonsequitur. I don't have a user account and I'm not sure how to fix it, since when I try to "edit" the line doesn't even show on the edit page - only the published page.

Can someone check it out?

Thanks, A.Pacchia

Is this what you were referring to? Seems that it was caught in about half an hour. Well it seems fine now.. in the future use WP:HD instead of this desk --froth^{T C} 17:11, 17 October 2006 (UTC)

USB Cables

I am interested in controlling electricity in a usb cable. My aim is to send a small but significant voltage to a device the other end.

I understand that there are three main parts to a usb cable, a live wire, a ground wire and two twisted wires for data.

Can the two power wires be controlled from a computer?

I don't really know what to search for, Google has given me a list of USB based products which doesn't help much and any pages which are related tell me information I already know.

Could you suggest some online resources which would make this easier or explain how i would go about doing it.

Thanks very much

PeteL 18:28, 17 October 2006 (UTC)

I suppose that actual functionality would depend on your USB controller, but the specification doesn't allow for any variation in power. You're better off just using the power lines for power and resisting it depending on what's on the data lines. USB uses differential signaling to reduce interference so you might want to read up on that before trying to design your own controller. Also the data lines are asynchronous so make sure it's not oscillating before addressing it to the resistors (or variable resistor). Or if I'm totally off here and you don't need variable power, just use the power lines and interrupt them when you don't need power (use the data lines to determine this) --froth^{T C} 18:54, 17 October 2006 (UTC)

Have you looked at our USB article, and more importantly, some of the external links on that page? --LarryMac 18:59, 17 October 2006 (UTC)

nivbamit 12:28, 23 October 2006 (UTC)

1. "Small but significant voltage" is not a term I can relate to - The USB standard (2.0 as well as the older 1.1) allows you to consume, from the embedded host, up to 5Vdc/500mA (total of 2.5W but check the USB spec for conditions). This power can be converted, within the allowed consumption limits, to whatever voltage/current combination using a DC-to-DC converter circuit.

2. The above power source is available, as described (and assuming your computer complies with the USB standard), from the two outer pins of the USB host connector.

These could be controlled by the host computer only if it is equipped with a power/load switch (normally, a power MOSFET circuit such as Fairchild's Load Switches). Some software driver for this function is required as well.

If the above are not provided in your computer, you will need to add them externally with some kind of a control (on-off switching) circuit. This control circuit could be based on a simple switch, the computer's parallel (or serial) port (with some software driver) or better yet, with an OTG USB controller (like Cypress' CY7C67200) attached to the very same USB port, which would allow you to (software) control this circuit from your computer.

3. The best online resources I'm aware of are the above mentioned Fairchild and Cypress sites, in addition to: Intel's Resource Center, the USB Implementers' website, and the Interfacebus site.

Nokia cell phone

i know this is not exactly a computing question but i hope one of you can help me out. i have a Nokia 3155i (Virgin Mobile edition). i know it can play MP3 and AAC because most of the ringtunes it comes with are in those formats. I am wondering how i could load my own MP3 music from my computer onto it and use it as an mp3 player. does it have a music player interface? i couldnt find it in the menus. Also, i know it only fits 12 MB. is there anyway to expand the memory?

They talk a little about connecting to your computer on their page, but don't mention sound files. You could always ask them. —Bromskloss 01:00, 18 October 2006 (UTC)