Domain: aau.dk
Stories and comments across the archive that link to aau.dk.
Comments · 24
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Re:It takes more than an antenna...
Actually, cubesats need at least a simple attitude control system, i.e., detumbling. Without one they spin up. See e.g. AAUSat II:
We are still working on finding the reason for the fast rotation rate, especially why it accelerated over the course of 40 days. We have a number of ideas, der include the torque caused by the magnetic dipole generated by the solar cells.
That said, being able to actually point in a specific direction with the sat is quite hard, and a lot of work.
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Re:HTML is dead... Didn't you notice?I tend to put (static) decorative attributes into CSS files since this is information that really doesn't change. Spatial information is calculated as a function of screen.width and screen.height. Being dynamic in nature it is assigned via JavaScript. A way around this would be to do the work upfront once (one of my general principles, actually), and then merely use JavaScript to control the loading of the screen size appropriate CSS files. I would then have decorative.load_always.css, and a dir tree of screen resolution CSS files only one of which gets loaded. Still a separation, although better use of CSS (as well as space-time tradeoffs).
Totally agree that an anchor tag link *is* (perhaps even the WWW's primordial) BEHAVIOR thing. Some RESTful types even go so far as to propose using the sum of the links a page has as the best definition of its state, and do away with state variables completely. I'm not that good/pure, but I do see it as one possible and interesting optimization strategy. Variables are quick and useful, sure, but a foreach is better than a for in so many ways.
Heretic that I am, in review of my current project I see that I've attached onclicks to tags (which calls an event handler, which checks for the id). I'm actually not using even a single anchor tag for its stated purpose. Too much AJAX? Does a site need more than one "page" if it can rewrite its elements? I honestly don't know. I enjoy exploring paradigms, yes. But I'm certainly not an authority.
I appreciate the XLink reference. In my current reincarnation (which cycles about every other fiscal quarter) I'd use their terminology to refer to all of my links as multidirectional in general, and specificly cyclic in nature.[Definition: Using or following a link for any purpose is called traversal.] Even though some kinds of link can associate arbitrary numbers of resources, traversal always involves a pair of resources (or portions of them); [Definition: the source from which traversal is begun is the starting resource] and [Definition: the destination is the ending resource]. Note that the term "resource" used in this fashion may at times apply to a resource portion, not a whole resource.
[Definition: Information about how to traverse a pair of resources, including the direction of traversal and possibly application behavior information as well, is called an arc]. If two arcs in a link specify the same pair of resources, but they switch places as starting and ending resources, then the link is multidirectional, which is not the same as merely "going back" after traversing a link.My links all involve dojo.xhrget, handleAs: json. I use lots of callbacks.
My next reincarnation, should I be happy enough to find someone willing and able to bankroll my journy, would be into the world of LAML (Lisp As a Markup Language). For those with ACM Portal access, and for the rest of us:ABSTRACT
Functional programming fits well with the use of descriptive markup in HTML and XML. There is also a good fit between S-expressions in Lisp and the XML data set. These similarities are exploited in LAML which is a software package for Scheme. LAML supports exact mirrors of the three variants of XHTML 1.0, SVG 1.0, and a number of more specialized XML languages. The mirrors are all synthesized from document type definitions (DTDs). Each element in a mirror is represented by a named function in Scheme. The mirror functions validate the XML document while it is generated. The validation is based on finite state automata automatically derived from the DTD.The LAML Hello World:
(load (string-append laml-dir "laml.scm"))
(laml-style "simple-xhtml1.0-transitional-validating")
(write-html â(TM)(raw prolog)
(html 'xmlns "http://www.w3.org/1999/xhtml"
(head (title "Hello World"))
(body (p "Hello" (a â(TM)href "http://www.w3c.org/" "W3C")))))
(end-laml) -
Re:Why not buy a nuclear plant...
In fact, nuclear plants have somewhat the same problem as wind power: You can't regulate production as you'd like. (Nuclear plants generally operate a lot better keeping a stable base load).
My department develops fuel cells, and we recently had a professor from the Sustainable Energy Planning Group give a talk on how to move away from fossil fuels. The main part of the solution is combined heat and power plants (CHP). In Denmark such plants already supply the heating for even small towns. The trick is that these can adjust towards producing either heat or electricity, and heat is way easier to store. (On the Nordic electricity market electricity prices hit zero once or twice a year due to abundant wind power, so any storage tech will earn money, though of course capital prices have to be offset). His scenario for Denmark on sustainable energy included greatly expanded heat storage. He also noted that while Denmark needs heating for housing around two thirds of the year, CHP is also relevant in a place like Thailand, where the heat is used in industrial processes.
I don't know if nuclear power is suited for CHP, in that case it would make a cheap, efficient and carbon neutral complement to wind energy. -
Re:Why not buy a nuclear plant...
In fact, nuclear plants have somewhat the same problem as wind power: You can't regulate production as you'd like. (Nuclear plants generally operate a lot better keeping a stable base load).
My department develops fuel cells, and we recently had a professor from the Sustainable Energy Planning Group give a talk on how to move away from fossil fuels. The main part of the solution is combined heat and power plants (CHP). In Denmark such plants already supply the heating for even small towns. The trick is that these can adjust towards producing either heat or electricity, and heat is way easier to store. (On the Nordic electricity market electricity prices hit zero once or twice a year due to abundant wind power, so any storage tech will earn money, though of course capital prices have to be offset). His scenario for Denmark on sustainable energy included greatly expanded heat storage. He also noted that while Denmark needs heating for housing around two thirds of the year, CHP is also relevant in a place like Thailand, where the heat is used in industrial processes.
I don't know if nuclear power is suited for CHP, in that case it would make a cheap, efficient and carbon neutral complement to wind energy. -
AAUSAT-II
One of the satellites is made by students at Aalborg University.
You can follow the status here:
http://aausatii.space.aau.dk/eng/ -
Increased Qtopia support on open devicesTrolltech is increasing support for Qtopia on open devices. You can already build, install and run Qtopia on FIC's Neo 1973 in addition to Greenphone. We are continuing to support open initiatives like OpenEmbedded and to participate in various open device developer gatherings like the Mobile Developer Days.
Best regards
Knut Yrvin
Community Manager Trolltech ASA -
Re:That was my experience...
Linux, or at least Ubuntu, has bigger problems.
It should not be possible for a fresh install of an OS to not have any video whatsoever.
But try installing the current version of Kubuntu on a Dell Latitude D630. This is possibly the most commonly purchased corporate laptop in the universe at the moment.
But do an install and just nothing ... black screen. Cant even open a terminal. I'm not sure how this is possible. Even windows has a software framebuffer driver that will do 640x480 on anything.
To get past this initial problem, I had to (after consulting with the local linux expert) actually go into the grub boot editor, and remove the /splash from the boot options. Otherwise, no video whatsoever, ever.
At that point, I could get a terminal, but still no X.
So right out of the bat, a standard nvidia video card, and the Intel a/b/g 3945, dont work out of the box. These are the two most common video cards and wifi cards in existence.
The broadcom 43xx gigabit nic was wonky as well, and it would cause error messages to flash across the terminal every 30 seconds or so. Even inside Vim, right across my content! I had to blacklist the drivers there.
And look at the insanity that has to be done to get it working:
http://www.control.aau.dk/~jdn/linux/d630/index.php?id=startside
http://ubuntuforums.org/showthread.php?t=481651&page=12
Video should always work, always, under every circumstance. There is no excuse not to have a generic framebuffer driver to fallback to. There is no excuse for an obscure grub startup setting to stop you from having command line access.
I'm not expecting everything to work out of the box, but there has to be generic fallback drivers.
I will say that the experience once I got the nvidia drivers downloaded and started was outstanding. NVidia makes a really nice script/program to build and install drivers, and fully configure X. That was really nice.
But why do I need the windows driver for my wifi card to use it under linux? Doesnt Intel open source their linux drivers?
Then after all that, everything was flaky and buggy. Gaim/Pidgin would randomly duplicate its own windows. Thunderbird crashes alot. Evolution would just 'disappear' after like the 3rd install wizard screen. No crash message, no warning, no complaint, just 'poof' and its gone.
And its not like I'm doing anything tweaky to install these apps, just apt-get install whatever. Not sure how I could be doing that wrong.
And dont even get me started on standby/hibernate. And how LVM will sometimes decide that it cannot install itself ... because it just cant. Sometimes yes, sometimes no.
Now ... all that being said, apt-get is wonderful. But honestly ... thats the only really compelling thing I could find with Kubuntu on that 630. Everything else was just a time sink and a royal pain in the ass. I'm sure it'd be better if I had a machine with certified drivers on a disc for everything. -
Re:Yea, it's all the same.
Seemed interesting to me too. Try http://www.cs.aau.dk/TimeCenter/pub.htm. Lots of stuff, not obvious where to begin.
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Mobile Developer Days
If your interested in mobile development, you can check out the Mobile Developer Days 2007: http://mobiledevices.kom.aau.dk/team_and_organiza
t ion/events/mobile_developer_days_2007/ -
Re:Everything I need to know about ants...
Funny. All I know about ants I learned from myrekrig: http://cs.aue.aau.dk/~fn/csp/myrekrig.html
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Google is your friendI can set up Samba, etc. on just about any box. What defies me is setting up OpenAFS.
Tell me how well it works.
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GET IT HERE!
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Re:Moogle? Doesn't he mean Moodle?
We at the Department of Communication, University of Aalborg, Denmark use Moodle as the primary communications channel for one of our study programs in multimedia. It works extremely well for us -- our students and lecturers love the simplicity of the interface, while also relishing its power. Teachers speak well of Moodle's didactically enabling features, and the ease with which they can structure the time-flow of their teaching using Moodle.
I am the administrator/help desk guy for our Moodle site, and I must say, it is easy as pie. I very rarely hear from anyone, and when I do, it's usually fixed in 15 minutes or less. I've been running our site for almost a year and a half now, and I've only spent something like 20 man-hours on it, all told. That includes spending time upgrading Moodle, fixing bugs in Moodle, AND supporting users. Moodle has a very active and very helpful user community at the Moodle site, which provides lots of help both to newbies and to seasoned Moodle veterans.
I've recommended Moodle for another Danish educational institution, and they've also been running it for a year and a half now, with very good results. The praise lavished on Moodle from their users -- teachers and students -- falls along the same lines as what I said above.
I can highly recommend Moodle as a Course Management System.
Ulrik Petersen -
Re:Design to construction in less than a year...
Well being one of the students working on SSETI-Express and also on cubesats I respectfully disagree.
The cubesat AAUSAT-IIthe we (the students at AAU AAU) are working on includes systems that are more advanced than many commercial satellites.
The communication system utilizes a CAN-bus which is something NASA is still doing feasability studies on. The attitude determination and control system provides full three axis stabilisation and control using magnetorquers and momentum wheels for actuation and sunsensors, magnetometers and gyros for sensing. This is also a first, especially in a 10x10x10cm cube with a mass of 1 kg.
The payload is a gamma ray burst detector from DSRI, danish space reasearch institute www.dsri.dk, which is being tested and spacequalified on this launch.
I think you should try to figure out how you would put:
EPS (Electrical Power System)
- solar cells
- batteries
- power conditioning
- power distribution
COM
- Antennas
- Transmitter
- Receiver
- Modem
ADCS (Attitude determination and control)
- Sun sensors
- Gyros
- Magnetometer
- Magnetorquers (coils)
- Momentum wheels (motors + flywheels)
- Various filtering, sensorfusion and control algorithms.
OBC (On Board computer)
- Microprocessor system
- Command and data handling
- Fault tolerance
- Software upload (in orbit)
Payload
- Actual payload
- + interfacing electronics
Mechanical structure
- Harness
- Structure
- Thermal analysis
All fitted into a cubesat (10x10x10cm) max 1 kg.
Ohh.. and when you're done, you have to space certify it all :-)
Good luck -
Re:Design to construction in less than a year...
Well being one of the students working on SSETI-Express and also on cubesats I respectfully disagree.
The cubesat AAUSAT-IIthe we (the students at AAU AAU) are working on includes systems that are more advanced than many commercial satellites.
The communication system utilizes a CAN-bus which is something NASA is still doing feasability studies on. The attitude determination and control system provides full three axis stabilisation and control using magnetorquers and momentum wheels for actuation and sunsensors, magnetometers and gyros for sensing. This is also a first, especially in a 10x10x10cm cube with a mass of 1 kg.
The payload is a gamma ray burst detector from DSRI, danish space reasearch institute www.dsri.dk, which is being tested and spacequalified on this launch.
I think you should try to figure out how you would put:
EPS (Electrical Power System)
- solar cells
- batteries
- power conditioning
- power distribution
COM
- Antennas
- Transmitter
- Receiver
- Modem
ADCS (Attitude determination and control)
- Sun sensors
- Gyros
- Magnetometer
- Magnetorquers (coils)
- Momentum wheels (motors + flywheels)
- Various filtering, sensorfusion and control algorithms.
OBC (On Board computer)
- Microprocessor system
- Command and data handling
- Fault tolerance
- Software upload (in orbit)
Payload
- Actual payload
- + interfacing electronics
Mechanical structure
- Harness
- Structure
- Thermal analysis
All fitted into a cubesat (10x10x10cm) max 1 kg.
Ohh.. and when you're done, you have to space certify it all :-)
Good luck -
Re:Tintin's Film Resume
The site mentioned above (tintin.qc.ca) gives indeed a good history of the Tintin movies. The series was adapted into several not-so-good movies already. I've seen them all.
:-)The Spielberg aficionados will take comfort in knowing that Spielberg had been negociating to buy the Tintin movies. He declared in an interview that after the success of the 1st Indiana Jones, he had money for some old film projects he wanted to do, among which a Tintin movie. He has been a long-time admirer of Hergé. Unfortunately, after Hergé's death, the negociations went nowhere.
The character of Chang in the "Temple of Doom" is a hommage to Hergé's homonymous character in "The Blue Lotus"
So one thing is sure. Spielberg is not doing this just because he's smelling money. He's taking Hergé's masterpiece as a work of art. That kind of approach generally gives decent results.
As a footnote, the person who heads the company that manages Hergé's copyrights and derivative is an American who married Hergé's widow. That person has acquired a rather sinister reputation for being absolutely merciless, some kind of male Hilary Rosen, not even allowing basic fair use.
--SysKoll
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Re:Artificial Gravity
If we were to develop a ship that accelerated at 9.8 m*m for the first half of a trip, and then slowed at the same rate for the second half of a trip, would that be sufficient for artificial gravity?
Read Georges Rémi's (Hergé) Objectif Lune ( Destination Moon ) and On a marché sur la Lune (Explorers on the Moon ) comic books for an excellent story on the design, building and use of an atomic-powered rocket to the moon (and back - including an attempt at spacejacking) which provides artificial gravity through continuous 1G acceleration.The fact that it was written 50 years ago in Belgium does not remove much of it's scientific accurary.
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Re:Artificial Gravity
If we were to develop a ship that accelerated at 9.8 m*m for the first half of a trip, and then slowed at the same rate for the second half of a trip, would that be sufficient for artificial gravity?
Read Georges Rémi's (Hergé) Objectif Lune ( Destination Moon ) and On a marché sur la Lune (Explorers on the Moon ) comic books for an excellent story on the design, building and use of an atomic-powered rocket to the moon (and back - including an attempt at spacejacking) which provides artificial gravity through continuous 1G acceleration.The fact that it was written 50 years ago in Belgium does not remove much of it's scientific accurary.
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Re:I think I'll wait for the box set...Ok, I'll explain. In the first edition of the Hobbit, that chapter is a bit different. Gollum did indeed wager the ring, not knowing that he had lost it (in both versions he doesn't realize it's lost until after the game is over). Finding that he cannot meet his bargain, he shows Bilbo the way out.
As the writing of the Lord of the Rings progressed, it seemed more and more out of character, so Tolkien rewrote the chapter, into the version you described. Tolkien later explained it as the first version being what Bilbo wrote in his own early accounts, at which time he was lying to himself to justify stealing the ring (in the same way that Gollum created the "birthday present" story). The later additions indicated a correction based on better,more accurate manuscripts Tolkien translated.
See http://www.daimi.aau.dk/~bouvin/tolkien/changesof
h obbit.html for more info. -
Use the source...
The homepage:
http://www.dfi.aau.dk/amo/qoptics/qoptics.htm
Direct links, that looked related:
http://www.dfi.aau.dk/amo/qoptics/qa.htm
http://www.dfi.aau.dk/amo/qoptics/
http://www.dfi.aau.dk/amo/qoptics/title.html -
Use the source...
The homepage:
http://www.dfi.aau.dk/amo/qoptics/qoptics.htm
Direct links, that looked related:
http://www.dfi.aau.dk/amo/qoptics/qa.htm
http://www.dfi.aau.dk/amo/qoptics/
http://www.dfi.aau.dk/amo/qoptics/title.html -
Use the source...
The homepage:
http://www.dfi.aau.dk/amo/qoptics/qoptics.htm
Direct links, that looked related:
http://www.dfi.aau.dk/amo/qoptics/qa.htm
http://www.dfi.aau.dk/amo/qoptics/
http://www.dfi.aau.dk/amo/qoptics/title.html -
Use the source...
The homepage:
http://www.dfi.aau.dk/amo/qoptics/qoptics.htm
Direct links, that looked related:
http://www.dfi.aau.dk/amo/qoptics/qa.htm
http://www.dfi.aau.dk/amo/qoptics/
http://www.dfi.aau.dk/amo/qoptics/title.html -
This Stuff Is Very Real
I am really hesitant to post anything about this since it will most likely be flamed to a crisp.
However, Mills stuff is just the tip of the iceberg. There has been quite a bit of active research in this whole, particularly in Japan and Europe.
The most interesting work has not been in the original electolysis using heavy water and palladium although SRI and to a lesser extent Los Alamos have been doing work in this area and have essentially confirmed the *original* observations of Pons and Fleischman. The major problem with this type of experiment is that you need to get close to a 1:1 (.9 as I recall) ratio of hydrogen atoms for each atom of the palladium crystal matrix before you get results. If you have cracks or other impurities you will NOT achieve that level of packing. If you use bulk materials the stuff gets explosive. One SRI researcher died from this. Also this whole area is *very* close to weapons research so Los Alamos has become very quite in the last couple of years while SRI is still plugging along. Here is a link to a page that has a nice summary of the issues.
The most interesting area, in my opinion, has been in the area of light water electrolysis where some people have seen signs of transmutation - which of course goes from 'fradulence' to 'outright witch craft' as far as conventional science goes.
Mills work is actually kind of on the sidelines from the 'mainstream' research in this area. He does have a lot of backing by reasonably conservative investors (2 mid size power utilities). He does have a comprehensive theory and has done numerous experiments to validate various aspects of his theory that have allegedly been confirmed by independent labratories.
Here is a link to a reprint of a recent Wall Street Journal article on BlackLight and its recent work.
Here are some other 'Cold Fusion' sites:
Cold Fusion Times
Infite Energy Online
BlackLight Power
Clean Energy Technologies a company that has done a lot with light water cold fusion and has recieved a number of patents in the area.
A Cold Fusion Bibliograph by Dieter Britz