Domain: utl.pt
Stories and comments across the archive that link to utl.pt.
Comments · 27
-
Re:Getting so tired of this "instantaneous" BS
It's a common misconception that QM as a theory of the microcosm is somehow more general and accurate than SR. Yet, the derivation of SR does not even require the constance of light speed (although that's the route that Einstein oribinally followed), but can be derived from very obvious first principles.
And this is a key difference to QM where this still hasn't been accomplished (despite the theory being such a fantastic empirical success story). Of course as far as empirical evidence goes SR also has a spotless record (which is why the CERN faster than light brewhaha was pretty much a forgone conclusion).
.
-
This was already solved by a portuguese in 2009
A portuguese aeronautics engineering student from Instituto Superior Técnico already figured this out way back in 2009 in his masters thesis, available here.
-
This was already solved by a portuguese in 2009
A portuguese aeronautics engineering student from Instituto Superior Técnico already figured this out way back in 2009 in his masters thesis, available here.
-
Re:Faster than light?
Relativity is based on the synchronization of clocks
This is an unfortunate and very common misconception. Most textbooks still follow the clock synchronization route to SR because that is how Einstein derived it in the first place. But as with most theories the oldest presentation and approach is usually not the best or most elegant one.
To derive SR all you need is some basic assumptions about space and time (homogeneity, isotropy) and one extra bit that you don't find in classical physics: The invariance of a particular speed in all inertial frames.
A nice presentation how this leads to SR can be found in this rather remarkable textbook that otherwise mostly deals with QM (Disclaimer: I am not the author nor do I know him or benefit otherwise from an endorsement).
Yet, there is even a more general approach to SR that can be taught on an introductory level. Here the assumption of an invariant speed is not required either and substituted by group law first principles that feel just as intuitively right as the assumption that space is homogeneous and isotrope. Namely we require that our transformations must always have an inverse one and a composition of them must result in the same class of transformations. Out pops SR.
This paper is really a thing of beauty. Professor who still teaches SR starting with clock synchronization should be punished to copy it by hand until their fingers bleed.
The sad thing is it has already been published 1976!
But to this day SR is still taught following Einstein's original convoluted path. Of course with the predictable results.
-
Free PDF of original article
For those who want to read the article before discussing it:
http://www.civil.ist.utl.pt/wctr12_lisboa/WCTR_General/documents/02455.pdf
-
Re:Love it!
Richard Stallman explains the practical ideology behind software patents. Parent states the gist of how it works.
-
European Universities do speak English
You'll find that many majors in Europe are taught in English. Some universities will even offer joint courses with american universities. Mine (http://www.ist.utl.pt/en/?language=en) offers shared degrees with MIT, CMU, UT Austin and a few other European ones.
-
Re:Does filtering really work?
I'm pretty sure it is throttling.
1) The global upload speed has high variability and, for long periods, averages way below my upload bandwidth.
2) There's a strong correlation between average download speed and upload speed (more than was ti be expected)
3) It started a couple of weeks after the limit of 30GB/month was removed.
4) The behavior (severity of throttling) changes from time to time -- see http://web.ist.utl.pt/~ist155741/temp/04.PNG And no, I had no other bandwidth-hungry applications running. This happens all the time. Other protocols (e.g. HTTP) work fine and do not exhibit any of these patterns.
Some people claim to have captured traffic between two ends and found extra RST packages, but, of course, I can't confirm that. -
Fenix
My university uses a self-built open source system, fenix to manage several thousand students. It's heavy and complex to install and configure, but it's great for the users. It's used in other universities and also powers our public site.
-
Fenix
My university uses a self-built open source system, fenix to manage several thousand students. It's heavy and complex to install and configure, but it's great for the users. It's used in other universities and also powers our public site.
-
google as diagnosis tool in odd pathologies
In some cases where diagnosis is tricky, google might help a lot... Don't you remember patrick volkerding??
http://ftp.ist.utl.pt/pub/slackware/slackware-curr ent/PAT-NEEDS-YOUR-HELP.txt -
V'ger 1 and Amateur DSN
This is a good place to mention Luis Cupido's web site. He's actually managed to pick up the Voyager 1 signal on a 5.6-meter dish, using a lot of DSP-fu and maybe -- you be the judge -- a bit of wishful thinking.
A fascinating, if somewhat slow-loading, page. -
Dangerous fun with Capacitors aside...
First off, the electroplating tank:
These are a blast. Everything looks better if you electroplate it!
Any of the cool looking, under the hood gagetry for your car, found cheaply at Schuks Auto would look better in gold. Any flat sided metal object can be enhanced with whatever artwork you can make a sillouette of on your computer, print in Press-n-Peel masking material
iron on, and plate.
Flatware should never be monochromatic
Your own Electron Microscope? Sweet.
The first thing to do is find the guy that's good at operating this and buy him several good lunches. Getting good images is tricky. That done, there is a world of stuff that looks better super close up, and best yet, the annoyingly black and white nature of this device lends itself to.... Yes! Electroplate sillouttes! Imagine how cool the aluminum case sides of your favorite computer would be if this were etched on the side. Your kids/nephews could have the coolest metal lunchboxes in the school. Like this or this or this or this.
A clear spray-on enamel will keep oxidation from uglying things up if your experiment with some of the more easily tarnished metals like copper and silver....
Sounds like you're in for a good time. Good luck. -
Fenix
My university develops and uses it's own open source system, Fenix. It's actually quite cool, and handles much much more than that, including course applications, classes management, timetables, exams and workgroups management, etc. I'm just not sure if it's fully available in english. At least the site seems to be.
-
Intelligence through Emotions
The way that AI is headed, I think that there may be robots that will be able to to menial work, e.g. cook, clean, build, etc. I don't think that AI will become an actual intelligence for some time.
An artifical intelligence is able to invent new things is something that may take much longer.
Although, I think that some researchers have realize what it is that made humans want to leard; Physical and Emotional needs. For all we know one of these needs driven robots could develop a more advanced intelligence than humans.
-
Re:Quite Right
Pretty graphics are information.
Applying ALT tags to images used as navigation elements is wise and good. Applying ALT tags to every single image is STOOPID. Some things cannot be rendered in words.
-
Scientology and Your Rights Offline
The Wayback Machine thing sucks, as do so many other Scientology actions against the net, but frankly I'm a little more concerned about how Scientology's actions affect people's rights out in the non-virtual world.
This is an organization that has framed critics, including journalist Paulette Cooper, who was indicted for sending bomb threats which, in reality, Scientology had sent to themselves. Scientology also attempted to frame Clearwater mayor Gabriel Cazares (for hit-and-run), U.S. District Judge Ben Krentzman (for solicitation and drug use), attorney Michael Flynn (for cashing a forged check), BBS operator Tom Klemesrud (for battery), attorney Graham Berry (for child molestation and battery), author Russell Miller (for murder), and former Scientologists Martin Hunt (for Internet posts; his report of the police officer's visit didn't mention what was being alleged about the posts) and Gene Allard (for grand theft - Allard won a 1974 malicious prosecution suit against Scientology).
Numerous instances of making false reports to police have been reported.
This is an organization that has seen 11 top-ranking executives go to jail in the U.S. for infiltrating government offices to steal and plant documents. In the similar Canadian trial, three Scientology executives and the Toronto church organization itself were found guilty of similar crimes.
The FBI raids in the late 70s turned up evidence of the frame-ups of Cooper and Cazares, along with evidence that Scientology had infiltrated numerous other government offices, such as the California Attorney General's office, as well as newspapers like the Clearwater Sun, law offices like Sidley & Austin, and other organizations, such as the Clark County Mental Health Agency. A Scientologist on the San Diego police force was fired for passing police information to Scientology.
A typical response from Scientology spokepeople is "that was years ago." (We never did that, and besides, we don't do it anymore.)
Well, there were five frame-up attempts that I can count in the past 3-4 years (Keith Henson, successfully framed and now a fugitive in Canada; Mark Bunker, acquitted; Bob Minton, acquitted twice but now apparently extorted into testifying for Scientology; Jesse Prince, hung jury).
There are also disturbing signs that Scientology is continuing to infiltrate government offices and businesses. A motion was filed just a couple of weeks ago alleging religious discrimination in the case of a woman who was fired from the Greenwich Housing Authority after Scientology management systems were introduced and employees were required to attend Scientology courses, paid for with thousands of dollars in public money, and the EEOC recently took action in a Texas case in which employees at a dental office were fired after refusing to attend Scientology classes. The Sacramento News & Review did a story not long ago about a publishing house that uses Scientology management techniques, run by Scientologists Dennis McKenna (who, as a Scientology spokesman, defended what Scientology did to Paulette Cooper) and Don Pearson (who gave extensive Scientology training to Allstate employees until management finally stopped it); the company, eRepublic, publishes a magazine on the use of technology in government (and another on the use of technology in education) and consults to governments on technology issues. The magazine includes ads for business training - never mentioning that it teaches Scientology principles - offered by people like Arte Maren - long-time Scientologist, co-conspirator in the 70s government infiltration case, and trainer in the Greenwich Housing Authority case.
I'm concerned that people confronted by Scientology training in the workplace don't know their rights. I hope the EEOC will vigorously defend people who are being illegally subjected to Scientology training at work - and I hope journalists will keep a closer eye on Scientology's continuing infiltration in government and business.
Kristi
Scientology Lies -
Scientology and Your Rights Offline
The Wayback Machine thing sucks, as do so many other Scientology actions against the net, but frankly I'm a little more concerned about how Scientology's actions affect people's rights out in the non-virtual world.
This is an organization that has framed critics, including journalist Paulette Cooper, who was indicted for sending bomb threats which, in reality, Scientology had sent to themselves. Scientology also attempted to frame Clearwater mayor Gabriel Cazares (for hit-and-run), U.S. District Judge Ben Krentzman (for solicitation and drug use), attorney Michael Flynn (for cashing a forged check), BBS operator Tom Klemesrud (for battery), attorney Graham Berry (for child molestation and battery), author Russell Miller (for murder), and former Scientologists Martin Hunt (for Internet posts; his report of the police officer's visit didn't mention what was being alleged about the posts) and Gene Allard (for grand theft - Allard won a 1974 malicious prosecution suit against Scientology).
Numerous instances of making false reports to police have been reported.
This is an organization that has seen 11 top-ranking executives go to jail in the U.S. for infiltrating government offices to steal and plant documents. In the similar Canadian trial, three Scientology executives and the Toronto church organization itself were found guilty of similar crimes.
The FBI raids in the late 70s turned up evidence of the frame-ups of Cooper and Cazares, along with evidence that Scientology had infiltrated numerous other government offices, such as the California Attorney General's office, as well as newspapers like the Clearwater Sun, law offices like Sidley & Austin, and other organizations, such as the Clark County Mental Health Agency. A Scientologist on the San Diego police force was fired for passing police information to Scientology.
A typical response from Scientology spokepeople is "that was years ago." (We never did that, and besides, we don't do it anymore.)
Well, there were five frame-up attempts that I can count in the past 3-4 years (Keith Henson, successfully framed and now a fugitive in Canada; Mark Bunker, acquitted; Bob Minton, acquitted twice but now apparently extorted into testifying for Scientology; Jesse Prince, hung jury).
There are also disturbing signs that Scientology is continuing to infiltrate government offices and businesses. A motion was filed just a couple of weeks ago alleging religious discrimination in the case of a woman who was fired from the Greenwich Housing Authority after Scientology management systems were introduced and employees were required to attend Scientology courses, paid for with thousands of dollars in public money, and the EEOC recently took action in a Texas case in which employees at a dental office were fired after refusing to attend Scientology classes. The Sacramento News & Review did a story not long ago about a publishing house that uses Scientology management techniques, run by Scientologists Dennis McKenna (who, as a Scientology spokesman, defended what Scientology did to Paulette Cooper) and Don Pearson (who gave extensive Scientology training to Allstate employees until management finally stopped it); the company, eRepublic, publishes a magazine on the use of technology in government (and another on the use of technology in education) and consults to governments on technology issues. The magazine includes ads for business training - never mentioning that it teaches Scientology principles - offered by people like Arte Maren - long-time Scientologist, co-conspirator in the 70s government infiltration case, and trainer in the Greenwich Housing Authority case.
I'm concerned that people confronted by Scientology training in the workplace don't know their rights. I hope the EEOC will vigorously defend people who are being illegally subjected to Scientology training at work - and I hope journalists will keep a closer eye on Scientology's continuing infiltration in government and business.
Kristi
Scientology Lies -
Re:Let's do some math....
Why don't you just use Drake's equation?
Or you could just use your bad logic. I can't believe this is +4, informative, should be -1, Troll. -
Re:Calendaring server is what we need
a quick search came up with
iCal 3.5
A very dynamic calendar utility that allows you to post dates on your Intra/Internet. November 3rd, 2000 Shareware 1.5MB win32
http://www.brownbearsw.com/ical/icalpage.html
ICal 2.2
ICal is a popular X-based calendar and scheduler application. September 28th, 1998 256.6K
http://wwwinfo.cern.ch/pdp/ose/asis/products/TCL/i cal-2.2/ical.html/
JetSync 1.0
Synchronizes your email, calendar (ical), memos and addresses and enables conduits for other types of data. February 22nd, 2000 GPL 213.3K
(I could not find the webpage but palm links to it)
http://mega.ist.utl.pt/~frias/jetsync/
Syncal 0.5
Syncal reads a current ical calendar file, an archived ical calendar file, and a Palm(TM) device DateBook database. April 12th, 1999 GPL 26.1K
http://hopf.math.nwu.edu/syncal/
lib ICAL 0.23
Lib ICAL is an open source implementation of the IETF's iCAL Calendaring and Scheduling protocols. March 28th, 2001 MPL 567.9K
http://hopf.math.nwu.edu/syncal/
yes I think that there is a lack of servers you can build yourself
companys often want to run servers on their intranet and dont want to far it out to a outside source (palm sells alot of their enterprise servers which do syncing)
personally the only app that runs this well and gets messaging right has been Lotus Notes Domino
frankly it rocks and I am surprised that Ximian have not picked up on this they have a client but no server and the server is where the money is !!
regards
john jones -
Re:hmm
-
Document MirrorWell after 5 hits, the server is barely responsive, so here's the page before the server completely dies:
Researchers at the Grupo de Lasers e Plasmas (GoLP) achieved the first milestone of the GoLP simulation program on Extreme Plasma Physics: the installation of the first Macintosh G4 cluster in Europe, called epp (or ep2), which is based on the AppleSeed paradigm developed at UCLA by Viktor Decyk et al. The epp cluster is capable of delivering over 50 GFlops of peak power, and it is based on 16 Dual PowerPC G4/450, 32 processors, 12 Gigabytes of RAM, 0.5 Terabyte of hard disk space, running Mac OS 9, over 100 Mb/s Fast Ethernet, switched by one Asanté Intracore 8000. This is the fastest Macintosh-based cluster in the World. The installation and set up of this cluster took less than 1 day (including moving the machines to the computer room, unpacking the machines, and making all the cables!), and it did not require previous knowledge of networking: a one-page recipe for Mac OS clusters can be found here (AppleSeed website) (Portuguese translation coming soon). This "supercomputer for the rest of us" will be used for the numerical simulation of plasmas, novel plasma particle acceleration schemes using ultra intense lasers, and relativistic shocks in astrophysics. This work supported by the Fundação para a Ciência e Tecnologia. More info available soon (also in Portuguese), as well as science using epp. For more information also contact Luís O.Silva(+351 21 8419 336).
---=-=-=-=-=-=---
-
What about xine? And vlc? And...?
This article sounds like oms brought DVD video to linux.
From a user's perspective, this is simply wrong: I've tried to compile oms for several months now, and I have only had partial success. All the people I asked about OMS had the same problems. Most of the time, the CVS snapshot didn't compile because some sub-parts of OMS were incompatible with others. On good days, it compiled, but had dozens of bugs...
At the same time, other Linux DVD players appeared: xmovie played the
.vob files, but with quite poor quality. VideoLAN presented a more useful DVD player, but it's user interface seemed a bit poor to me.In November 2000, I had my first glimpse on xine. In those days, it was a tiny new project, not even designed to play DVDs "for legal reasons", as the xine people always say. But it had one remarkable feature: It simply worked! I Just had to configure; make; make install and it even played (unencrypted) DVDs. After a few days of searching, I even found the CSS Plugin, which enabled xine to play encrypted DVDs. Again, it was trivial to install...
In the Meantime, there has been a rush of new xine versions. The player has become much more mature, and it supports most features I need for DVD playing, even subtitles. The developer team has been very helpful. They really try to satify user needs. There are precompiled RPM, Slackware and Debian packages. The source is extremely portable, there are people running xine on FreeBSD, or even PowerPC machines.
To make it short: Xine simply works. I never had a reason to switch again...
xine links
xine homepage
css descrambling plugin
"complete xine", xine including the css plugin -
Summary
It seems we have gone from none to too many movie solutions for the free unices. I am amazed at the sheer amount of duplication, but I guess that is the way we do things in the free software world.
GPL Movie systems listed from most mature to least, imo:
-
Many options for DVD on Linux
I don't mean to try and take away from the LiViD team. They were the first to start working on a DVD player for linux, and there work has provided the basis but there are several other DVD players for linux. But there are other players which many have reported to be better than oms in the areas of configuration, performance and audio sync. One of these is call VideoLAN which several others have mentioned. It now has css support much like OMS and the performance is suppose to be quite good on lower end system. VideoLAN is not quite as old as OMS but the source was only made available more recently hence less exposure. I believe most of the code in VideoLAN was developed independently of LiViD code except css of course. There is another which has called Xine which is the newest one but reported to be one of the best. I believe this one used the LiVid video and sound system but has tweaked synchronization and performance as well as adding some other feature. This one is also designed to be compatible across several free unix type platforms including *BSD. Note that the standard version of Xine does not come with css support but it can be added with a plugin from here as well as a version with the plugin already built in here. Again what LiViD has done is great but competition as always is good. The only thing I would like to see is some unified plugin standard for these players so that any css plugin could work with any of the DVD players. That way if new DVD's come out that break the current CSS updates could occur much easier for all the projects.
-
Re:"Protected" DVDs?
Sure is: http://gape.ist.utl.pt/ment00/linuxdvd.html.
I haven't tried it yet, but people on the Livid User list are using it. I just downloaded it and will try it out. -
Use the mirrors....There's a whole world of mirrors out there: