Today, the professor handed out small bags with a white powder to me and my fellow students. As I mentioned before, I have to grow a crystal from a powder, for the professor's class. And today the powder arrived so I can start growing my crystal.
I went to the supermarket to get demineralised water. I can't use tap water, as this contains to much calcium and other substances that could affect the growing of the crystal.
Back home I mixed some powder with the water and stirred until the powder was completed dissolved. The liquid is clear again.
Then I added some more powder and mixed again, but this time not all of the powder is dissolved. That's normal as I calculated how much powder could be dissolved in the water at room temperature. By adding some more of the powder, the solution becomes saturated, thus it cannot dissolve more of the powder.
By heating the water a bit, the water can dissolved more of the powder. I put the beaker in the microwave for about 40 seconds and stirred again. Now all the powder, even the excess powder, is dissolved, resulting in a clear liquid.
When the water cools down to room temperature, the liquid remains clear, thus the solution contains more powder than it previously contained before heating. This means the solution is oversaturated. That is what is needed to start growing a crystal.
First I need a seed crystal, so I put a thin copper wire in the oversaturated liquid, in order to let a seed crystal grow on the wire.
Now I have to wait for the liquid to cool down further and let the seed crystal(s) grow. I'll check back in a few hours before I go to sleep, but I expect to see something when I wake up in the morning.
(I would post some pictures of the process, but I don't have a (digital) camera, so you'll have to believe what I'm describing)
Tuesday, November 13, 2007
Today, the professor handed out small bags with a white powder to me and my fellow students. As I mentioned before, I have to grow a crystal from a powder, for the professor's class. And today the powder arrived so I can start growing my crystal.
Wednesday, October 24, 2007
A pure work of art, absolutely brilliant. That's how I would describe the new episodes of BBC drama series Spooks, of which series 6 started last week on BBC1.
The first story spans the first two episodes. In the first episode, a threat of a fast spreading lethal virus in London is introduced. In the second episode it gets even more harsh, when MI5 decides to abduct spies of befriended nations like USA, Russia and France and threats to infect them with the virus, to persuade them to reveal the location of the antidote. MI5 believes one of those nations manufactured the virus and must have produced an antidote as well, but are certain the only way to get them to admit this antidote exists, is by these extreme measures.
In the end the antidote is found and all infected victims are cured, but relations with intelligence services of befriended nations are very hostile because of the abduction. And this will most definitely dominate the storyline of the next episodes. I'm really looking forward to it.
Sunday, October 14, 2007
Some time ago, I figured out I don't have enough time to spend on things I do, like doing and would like to do.
I realize it is impossible to create more time, so over the past few weeks I have come to the conclusion I need to be efficient at spending the available time and give priority to important and necessary things like sleeping and working.
As the academic year started a few weeks ago, I set a high priority to attending classes and studying as well, or this might be my last year as a student.
All others things, apart from spending time with friends and family, get a lower priority. This means I spend little to no time on certain activities, like attending meetings and staying up to speed with all details in the news. And some things I skipped totally, like going out during the week.
So the keyword in all this is priority, and acting according to it. This means I sometimes have to say no, or when I fail to do so, take the consequences by not being able to do something else.
Posting on this blog is one of the low priority things. It's not that there isn't anything to post about, but I lack the time and the motivation to write about it. When I feel like it, I will post something, if not, you can check the insert with shared news items on the right side of this blog. I add items regularly when I come along something that might be of some interest.
Thursday, September 27, 2007
In the exercises class of my Crystallography course, an assignment was given :
Craft a cube and bring it to class next week. It can be made of any material. You will need it to help you with the exercises.
So I cut a cube out of some insulation foam. But I'm not completely pleased with the result.
First I thought of making a cube from cardboard, by drawing some squares, cutting them from the cardboard and folding them together. But I figured this cardboard cube would be crushed when transported in my backpack, so I needed some structure that's not hollow.
Insulation foam is very light and relativily easy to sculpt, so I chose this material and started creating my cube, by measuring, cutting and sculpting. The end result looks like a cube, but not all sides are completely square. But it will do for the exercises.
This course starts to become some sort of handywork class, as in a few weeks we will be instructed to grow a crystal at home, starting from a beaker containing a dissolved substance. It's all very exciting. :-)
Saturday, September 22, 2007
Next monday, a new academic year starts. This means : new courses and new lectures.
So it is time to archive some of my previous courses and make room for the new ones.
As it happened to be, there was still studying material of my first year Eastern Studies somewhere on a shelve. Because I won't need it anymore, I switched to physics and astronomy two years ago, I put it together in two small piles, made a list of the courses in each pile and bound them together with a string. The piles are now stored with the other archived studying material in another room.
With the old material out of the way, the courses of last year, which where on my desk, now take the free spot on the shelve, as I might want to look something up during the next two semesters.
The available space on my desk will soon be taken by the new studying material for next semester.
Thursday, September 20, 2007
Today I went shopping in Antwerp, to buy some clothes. I left by train in Ghent at 13u13 and arrived in Antwerp about 45 minutes later. Then I went to 'De Meir', the biggest shopping street in Antwerp and bought the following things :
- 1 pair of shoelaces
- 3 trousers
- 4 T-shirts
- 3 pull-overs
I left again by train at 15u06.
The shopping spree took me under 3 hours, to buy enough clothes to have no need to going shopping for another year.
People might wonder why I went to Antwerp to buy clothes. If I would have shopped in Ghent, I might have spent even less time. The reason is simple : I like going to Antwerp once in a while, and the shop where I usually buy my clothes is bigger in Antwerp than the one in Ghent, so there are more clothes to choose from.
Thursday, September 06, 2007
A long awaited search function is added to Google Reader.
Now you can search newsfeeds you previously read. If you know you read a newsitem about something, but can't remember on which feed it appeared, just search for it in Google Reader and the post will turn up.
Sunday, August 26, 2007
Ironkey as a robust, secure and tamperproof USB key, that stores your data with hardware encryption, remembers your passwords, contains a portable version of Firefox and can be run over by a car or get wet without loosing your data or stop functioning.
It even protects your data from being stolen : when someone fails 10 times to supply the correct unlocking password or when someone tampers with the housing to get access to the electronics inside, the USB key starts self destructing.
Don't expect a Mission Impossible style self destruction with a voice counting down and a lot of smoke. The self destruction sequence is hardware based and erases the flashmemory, which renders the USB-key unusable afterwards, so watch out when you forget your password or mistype it a few times.
With the Ironkey, you can carry all your personal information completely secured. All your passwords are stored on the key, so you don't have to remember them and you have them with you all the time. This enables you to use different strong passwords for all the websites you use, which is much more secure than using the same simple password for every site you ever visit.
Because there is an imbedded version of Firefox running on the key, you can use it on computers that don't have Firefox installed and you don't leave sensitive information like cookies, stored passwords and surfing history on that computer.
Unfortunately, the USB-key only works with Windows XP and Vista. But the site announces they are working on a version that works on Linux and Mac too.
The basic version has a storage capacity of 1GB, but 2 GB and 4 GB versions are also available. At this moment the shop on their website doens't ship the USB-key outside the USA, but maybe it will be available with other retailers.
Thursday, August 23, 2007
The Financial Times reports, Apple has signed contracts with Orange, O2 and T-mobile for exclusive use of the iPhone on their networks in Europe. This means the iPhone can only be used on the networks of these providers and not with other mobile providers.
In June, when the iPhone was released in the US, iPhone users could only use their new phone on the network of AT&T. Apple had signed an exclusive contract with AT&T for a two year period.
Initial release of the iPhone in Europe, is planned for the autumn. But it will only be available in Germany, the UK and France. The iPhone will be released in the rest of Europe, in the beginning of next year.
For Belgium this means the iPhone will probably be available in spring 2008, and only on the Mobistar network, as Mobistar is part of the Orange group.
A survey of Eos, a Belgian scientific magazine, revealed that young people (aged 18-24) know far less about scientific facts than older generations.
On a questions like 'Does planet earth revolve around the sun?', one in three didn't know the right answer. Even older generations (+65) did better on this question.
An explanation for this is the changed focus in education from factual knowledge to teaching of skills to resolve problems. Young people don't seem to be interested in science as well.
This trend doesn't only show in Belgium. In the United States, politicians fear the US won't be competitive in the scientific field, because not enough student take on maths, science and engineering courses in college.
If you want to know, how you would score on the test run by EOS, you can take it here (in Dutch).
Sunday, August 19, 2007
You're a Doer.
You are very quick at getting tasks done. You believe the outcome is the most important part of a task and the faster you can reach that outcome the better. After all, time is money.
You like coding at a High level.
The world is made up of objects and components, you should create your programs in the same way.
You work best in a Solo situation.
The best way to program is by yourself. There's no communication problems, you know every part of the code allowing you to write the best programs possible.
You are a liBeral programmer.
Programming is a complex task and you should use white space and comments as freely as possible to help simplify the task. We're not writing on paper anymore so we can take up as much room as we need.
I came along this programmer personality test on the blog of Jan, an old classmate.
Saturday, August 18, 2007
Some time ago (31st of May 2007), Google Gears was launched. Yet another new project, next to all the other applications Google has launched already.
But this one is different. It's not a stand-alone application, like Gmail or Google Analytics, but a framework that makes it possible to store a website or a web application offline, so you can still visit this website or use this web application while you are not connected to internet.
To show what the framework does, a new feature was implemented for Google Reader, an online news feed (RSS/Atom) reader, that makes it possible to read newsfeeds while offline. This feature uses the Google Gears framework.
I've used it for a while now, and I must say that it works well. When I'm traveling by train for example, I switch to offline mode in Google Reader, before I leave home.
When going to offline mode, Google Reader downloads 2000 messages and stores them locally. On the train, I open Google Reader in my browser and start reading the news messages, just like I would when connected to the internet.
When I get back home and switch back to online mode, Google Reader synchronises with the online version. All messages I read offline, are marked as read and the starred or shared messages are set.
I'm wondering which Google applications will be next to have an offline mode, using the Google Gears technology. An offline version of Google Calendar would be nice. ;-)
Thursday, August 16, 2007
MySQL database server has a master-slave replication feature, which makes it possible to have a complete copy of a master database on a slave server. When the master server should fail, you have a copy available immediately, so you don't loose data and you can switch your applications to the slave-server while bringing back up the master server, so the downtime is small too.
A drawback of this master-slave replication is that it is a one-way backup. The slave server is a complete copy of the master server : all changes that are done on the master server are applied to the slave server, keeping them identical.
But because it is one-way replication, changes to the slave database server aren't applied to the master server.
I just came along an article explaining how to set up two-way replication : both servers are master and slave at the same time. So it doesn't matter on which server the database is changed, the change will be applied to the other server, which always results in two identical databases.
I'm thinking of using this setup to synchronise the database of my server at home with the database running on my laptop. This way I will have a remote backup of my database server on my laptop, in case something happens to my database server at home.
But also, all changes that I make to the database on my laptop while not at home, will be synchronised with my database server, when I get home.
This good HOWTO on setting up (one-way) master-slave replication, also provides a simple, but working, script to make a daily backup of a MySQL database server.
Wednesday, August 15, 2007
When studying, analysing, interpreting and describing a situation, be it social, cultural or philosophical, that differs from your background, you will always be influenced by your background. This is unavoidable, no matter how hard you try.
But what if you have different backgrounds? Everybody grows up in a cultural setting and compares what's happening in the world outside to the values and habits of the background one is raised in.
If you would swap backgrounds after a few years, by, for example, emmigrating to a different region, you will, after a while, get to know the values, views and habbits of the new region. This way your cultural background consists of both environments you have lived in. If you would get to know several different settings, your background would consist of many different views.
If you would have multiple backgrounds, wouldn't it be easier to study other situations without being influenced by your background? Because you have more than one background, you can't compare to just one cultural view, as you are aware of more than one.
One must ask if it is possible to get to know several different cultures, without forgetting about the previous ones. But you must of course be willing to adopt new views.
Monday, August 06, 2007
In the future, search engine Google will look like a combination of Google and Wikipedia. When you search for something on Google, you will get a wikipedia-like explanation of the term you are looking up and a list of categories to further refine your search, rather than a list of most relevant links, as you get now.
The links won't disappear completely, you will still be able to visit relevant web pages, but the links to these sites are highlighted words in the explaining text or in the biography, or 'See also' section, at the end of the small article.
The content for the small article and the categories isn't provided and edited by a community of people sharing knowledge, but is derived from all information that is accessible, like webpages and digital libraries. For this to work, an algorithm (computer program) is needed that can scan documents, articles, blogposts and webpages and understand what it is about. Some people call this AI, or Artificial Intelligence, others would define this to be base of the semantic web.
Rather than looking for the occurance of search terms in the indexes of all webpages, the search sites of the future would understand what the search is about and answer what it 'remembers' about it, after 'reading' and 'understanding' all available sources on the internet.
I'm not affiliated with Google or any other company offering internet search services. What I described is my vision on the future of websearching and looking for information. My vision is much like, and is probably influenced by, the view of Tim Berners-Lee, one of the founders of the internet, on web 3.0 and the semantic web :
I have a dream for the Web [in which computers] become capable of analyzing all the data on the Web – the content, links, and transactions between people and computers. A ‘Semantic Web’, which should make this possible, has yet to emerge, but when it does, the day-to-day mechanisms of trade, bureaucracy and our daily lives will be handled by machines talking to machines. The ‘intelligent agents’ people have touted for ages will finally materialize.
(Berners-Lee, Tim; Fischetti, Mark (1999). Weaving the Web. HarperSanFrancisco, chapter 12. ISBN 9780062515872)
The ability of computers to understand texts, rather than searching for occurances of words, is until now not possible. A big goal in computing was set out by Alan Turing, famous mathematician and the person who cracked the Enigma-code of the German army during the second World War.
The Turing Test defines that a computer must be able to have a conversation with a human, where the human is unable to tell wether he or she is talking to a computer or another person. A computer that passes the Turing Test is considered to be thinking, interpreting and understanding on its own.
When computers (or algorithms) could pass the Turing Test, they would be able to understand and interpret every available text and information and connecting it to other texts or concepts, just like humans would do, thus making the semantic web possible.
Until now, computers haven't passed the Turing Test, so we have to do with the current search technologies aided by human understanding, like I mentioned in Computers need help or projects like ChaCha.
Saturday, August 04, 2007
It's weird what can happen when going out. You know were you begin, but you never know where and when it will end.
The evening started with Transformers, which I saw with Brecht. Afterwards we went to Viewmaster 07, to meet Brecht's girlfriend Tine and some friends (Sophie, Lore). Because the film they showed, L'empire des senses, was a bit of a bore, we went for a drink in L'heure bleue, near Sint-Jacobs.
There we met two Australian people, who were staying at Sophie's place. They are on a trip through Europe and got to know Sophie on the couch surfing project.
Afterwards, Sophie, Lore and I went to a bar called Maritime, after Sophie got a message of a friend telling that a party was going on there. It turned out to be a bar with old people with a DJ playing old music. We left and went to Video, a popular bar in Gent, near De Oude Beestenmarkt.
There we met Koen, who works for a company called oneDotOnly. They design websites, organise events and do creative things.
The evening ended at his place, where Lore, Koen and I drank a nightcap. I went home at 7 in the morning, while the sun started to set above Gent.
It turned out to be a very strange night, meeting a lot of new people. I had a good time.
Friday, July 27, 2007
When displaying a screen with a white background a monitor consumes more energy than showing a black background. That's true at least for (older) CRT type of computer monitors. A study points out that a CRT monitor uses 75 Watts displaying a white background, but only consumes 59 Watts when showing an all black background.
This is not true for LCD type of monitors, as the background lighting is always on, even if some or all parts of the screen are black. But LCD monitors are far more energy efficient than CRT-monitors.
Using a site like Blackle, a version of popular Google search engine with a black background, could globaly save 750 Megawatts per year.
Sun created a plugin for Microsoft Office (2000, XP and 2003), which makes it possible to save documents in the Open Document Format (ODF). ODF is the format used by OpenOffice, StarOffice and other programs to save documents.
Monday, July 23, 2007
In May, no mail was delivered for nearly a fortnight in my town, because of a strike of the postal service.
During those two weeks, there was a national strike of the postal services, resulting in no mail delivery nationwide, for one day. Because of this one-day strike, the CEO of the postal service published a letter of apology (subscription needed) in all major newspapers.
Today, I, and all other inhabitants of my town, received a letter of the postal service, apologizing for the two week strike and all the trouble it caused. As a symbolic gesture, ten free stamps were included in the letter. Thank you, postal service!
But I would prefer not to have such a long term strike in the future, even if they offer me a thousand free stamps afterwards.
Saturday, July 21, 2007
Yesterday, Google announced its quarterly results.
Although Google had a profit of 925 million USD, which is 28% higher than last quarter, analysts were 'disappointed', because operating expenses were much higher than expected.
This 'bad news' caused the exchange rate of Google's stock to drop over 30 USD (about 6%) this morning when NYSE* opened.
During the day this loss was slightly restored, but today the value of the Google's stock dropped to a rate of a month ago.
I know stock exchange is sometimes irrational, but am I the only one to see that an increase in profit of 28% is rather well? Google's stock should have gone up today, not down.
I realise that profit could have been bigger if there had been less expenses, but a company like Google should invest in development, which costs money, in order to maintain its growth.
But probably the stockbrokers who caused the drop of Google's stock by mass selling this morning, were smart enough to sell when the stock rate was high and bought those stock back after prices had dropped massively, thus making about 30 USD per stock.
And suddenly stock exchange seems less irrational.
But then again, maybe now is a good time to buy Google stock, they're a lot cheaper than they were yesterday. ;-)
* NYSE = New York Stock Exchange, Google's stock is noted on NASDAQ
Tuesday, July 17, 2007
Some time ago I wrote about computers needing human assistance for certain tasks, like recognizing images or understanding text.
This time astronomers need human intelligence to assign pictures of distant galaxies to a few categories. This is another task, that's trivial for human but immensely complex and error prone for computers.
The project is called Galaxy Zoo and its concept is simple :
A picture of a galaxy is shown to you and you have to decide which category it belongs to.
This is how you get started : After registration, you get a small tutorial explaining the different types of galaxies. After the tutorial you have to do a small test where you get 15 pictures of galaxies and you have to decide which category they belong to. When you get 8 out of 15 correct, you can start sorting new galaxies.
I haven't figured out what caused the outage, but I was cut off from internet the entire evening. Maybe the intensive rain flooded a local hub?
As the internet connection uses the television cable, I wasn't able to watch television either.
At first I was a little annoyed, but this soon faded when I realized I could read instead of watching television or spending some time on the internet.
I was able to finish a book I started reading on the train traveling to Barcelona and read some articles I had lying around.
It turned out to be a very enjoyable evening, listening to music and hearing the sound of extensive showers in the background while reading a good book.
BTW : The book I finished was 'Het derde huwelijk' (The third marriage) by Tom Lanoye.
Monday, July 16, 2007
Earlier this year, I mentioned going on a trip to Barelona.
Well. I went, I saw and I enjoyed it.
One of the things I enjoyed most, was the metro system. It is very practical : you enter a station somewhere in the city, take a train, maybe switch lines halfway and leave a metrostation in a totally different part of the city in no time.
I noticed that the metro trains in Barcelona are airconditioned, but the stations are not. Once you're on a train the temperature is enjoyable, but in the stations it can be realy hot. It is sometimes even hotter in the stations than it is above ground.
Prices are acceptable. You pay 1,25 EUR for one ride, but when you buy a pass for 10 rides (6,90 EUR) or a one (5,25 EUR) or two-day pass (8,30EUR) , it costs even less.
You can use the same ticket on bus and tram in the Barcelona area.
Wednesday, June 27, 2007
Yesterday, my fileserver crashed. I noticed this when I tried to check my mails and couldn't connect to internet. (The fileserver also serves as DHCP and DNS.)
Because I had an exam this morning, I couldn't investigate why the server had stopped working.
Tonight I had some time to look into it. After some testing I found out the power supply (PSU) failed.
So I can repair my computer by buying a new PSU tomorrow, instead of having to replace the motherboard. So, I'm quite lucky.
Strangely enough I replaced the PSU with a a more expensive one only last year. According to its specs it would last for nearly four years. It turns out that the PSU doesn't comply with its specs. :-(
Sunday, June 03, 2007
Anna Vinnitskaya won the first prize of the Queen Elisabeth contest for piano 2007. As I mentioned earlier this week, Anna Vinnitskaya was a strong favorite to win this year's edition of the contest.
Second prize was for Plamena Mongova. Third was Francesco Piemontesi, and Ilya Rashkovskiy, who impressed yesterday, was fourth.
The only Belgian finalist, Liebrecht Vanbeckevoort, got the sixth prize. He also won the Klara-Sternefeld prize, which is awarded by the public and the viewers and listeners on radio and television.
For a complete overview of the laureates and finalists, you can check the Klara website.
It was the first time since 1968 that the Queen Elisabeth contest for piano was won by a woman.
It was also several years ago that a Belgian contestant was able to reach the finals.
Saturday, June 02, 2007
Last night, Dutch television station BNN broadcasted a game show called 'De grote donorshow' (The big donor show). 'Lisa', a terminally ill woman with a brain tumor, who turned out be an actress, was to donate a kidney to one of three contestants during a 80 minute TV-show. She had to choose who was going to get her kidney after talking to them and their families.
At the conclusion of the show, when Lisa had to choose, the moderator revealed that the show was a hoax. The ill woman was in fact a healthy actress. The contestants were really waiting for a kidney to be donated, but they were informed that the show wasn't real.
The makers of the show didn't plan to do an actual donor contest. The goal of the hoax was to draw attention to the lack of organ donors in The Netherlands. Five years ago, BNN founder Bart de Graaff died, because no suitable kidney donor could be found to help him.
The show drew a lot of attention in The Netherlands and abroad. Both CNN and BBC reported about the fake donor show. It seems the producers of the show reached their goal.
Thursday, May 31, 2007
The final of the Queen Elisabeth contest for piano 2007 has started on monday and is now halfway.
Six finalist have played, with six more to come. The standard throughout the week was very high, but the second finalist that played this evening was absolutely amazing.
Anna Vinnitskaya started her performance tonight with a Beethoven sonate (Sonate n.13 in Es op. 27/1 “Quasi una fantasia”) which she played as it was meant to be.
Then she played Prokofiev's second piano concerto. And it was beautiful.
This concerto is immensely difficult to play, so the commentators on television said, but she played it like she does this all the time. Maybe she does, which might explain why she played it so well. ;-)
Both the public and panel on television were very enthousiastic about her performance.
With another six finalists that have to play in the next three days, one can only hope that all of them play equally well. But if they don't, Anna Vinnitskaya has a very good chance to become this year's winner.
Last week I came along a device, called Slurpr, on the blog of Geektechnique. The creators called it 'the ultimate wardrive box'.
It is designed to access up to six wireless networks, in order to accumulate the bandwith of the wifi's it is connected to and get a massive total available bandwith.
Although wardriving and accessing other people's private wifi's is actually forbidden, this is still a very cool gadget.
It seems other people on the internet have noticed this device too, as this webcomic already mentions the Slurpr.
Monday, May 21, 2007
This film explains what copyright is, using parts from Disney pictures. It is quite neatly done.
Now let's hope this film could be considered a parody, otherwise it's not fair use of copyrighted material and thus illegal. ;-)
The mail service in my town is on strike for over a week now. This means I, and all other inhabitants of my town, haven't received any mail since.
The employees of the mail service are on strike to protest against Georoute2, a software application that was implemented last summer to optimize the delivery of mail. They claim the work pressure has gone up since the new software is being used.
I can do a few days without mail, I'm expecting no important letters or bills. But now, the strike is on for more than a week, and I'm starting to wonder about a few things.
Is there any important mail for me, that is delayed now, because of the strike?
When will the strike end?
If the strike ends tomorrow, how many days will it take the postal service to deliver all delayed mail?
Isn't this going to cause even more work pressure for the employees, until all delayed mail is delivered?
If the strike takes much longer, will there be an alternative to get my mail?
What if I receive some bills past due date, because of the strike?
Optimus Maximus sounds more like the name of an Emperor or warlord from the Roman Empire, but actualy it is the name of a very cool keyboard.
On first sight it seems to be a normal keyboard, with some extra colourful buttons. But what makes this keyboard special is the buttons. A small LED-screen is fitted into each button, making the keyboard-layout fully dynamic. The keyboard can have azerty, qwerty or dvorak layout, but can also show Cyrilic, Arabic, Chinese or Hindi characters on the buttons. All buttons are fully adjustable and you can add your own (moving) images to each buttons.
This keyboard was in a development stage for quite some time now, but starting this week it can be pre-ordered. The first 200 to order the keyboard will receive it in the beginning of december 2007.
There's only one small drawback to this very cool gadget keyboard : it's priced approximatly at 1250 €.
Saturday, May 05, 2007
Yesterday, I ordered train tickets for a trip to Barcelona and today I headed over to the train station to get them.
It was quiet in the station hall, no one seemed to take a train at that moment, so I went to the counter and told the person behind it I had ordered some traintickets and would like to get them. She asked me for the reservation code and some details about payment. Everything went well and soon my tickets were being printed.
But then two ladies entered the station hall en came to the counter, standing behind me, waiting to buy a train ticket. There was only one counter available at the time, so they had to wait until I had finished receiving my tickets. Because the transaction of printing ordered international train tickets takes a little longer than buying a local trainticket, the two ladies behind me started mumbling after about a minute of waiting: 'Why does it take so long?' It seemed that the noun 'to wait' didn't occur in their dictionary, as one of the ladies soon stood next to me repeating the same question.
Naive as I am, I responded that I was getting some ordered tickets, but that she could get her ticket at an automatic ticket dispenser located a bit further in the station hall. I suspect she didn't like my answer, looking at her facial expression while she mumbled something like, 'Me? Do 'I' have to get my ticket there?' Later, I realised she probably wasn't aware something like an automatic ticket dispenser existed, let alone that she knew how to operate one.
But she gave it a try, heading over to the machine, but soon returned to the counter, standing next to me while trying to get the attention of the person behind the counter.
The woman behind the counter ignored her and continued handling my tickets and started explaining which tickets I had ordered before putting them in an envelope.
Then the lady next to me started talking to the person behind the counter, telling that she needed a train ticket urgently.
The woman behind the counter answered : 'I'm busy, wait your turn.'
Then the woman next to me replied : 'But I need to get a ticket urgently, I'll miss my train.'
The woman behind the counter responded : 'I can't be bothered, I'm handling an international dossier. Wait your turn.'
The woman behind the counter continued putting my tickets in an envelope, while the woman desperatly needing a train ticket backed off. When the woman behind the counter handed me the envelope I thanked her, wishing her a nice evening and started heading out of the station hall. While I left, I heard the woman, who stood behind me earlier, ordering her train ticket.
I think I was less than five minutes in the train station, which was not such a long time for getting international train tickets. I remember standing behind a couple ordering their international train tickets with only one counter available in the station, when I needed to get a train ticket, with the departure of my train getting nearer as minutes passed by. I don't remember clearly how long I had to wait then, but I'm quite sure it took longer than I had to wait for my tickets today. But I got a ticket and that train on time, probably with seconds to spare, but who cares about that when one gets on a train right on time.
Normally, I use a railpass for 10 rides, that I have to fill in before getting on a train, so I don't need to wait at the counter before I can get my train.
But if I have to buy my ticket, I use this rule of thumb : 'Leave 10 minutes earlier, in case you have to stand in line before you can get a train ticket.', a rule of which the two ladies behind me probably hadn't heard before. If you don't have to stand in line more than 10 minutes, you can get your train without rushing and maybe you have time to buy something to drink or enjoy the sun or the people passing by while standing at the platform. If you do have to wait for more than 10 minutes, well, then there's nothing you can do about it, but wait. There are plenty of trains to come after the one you are missing. Missing a train gives you even more time to enjoy the sun at the platform, or watching people in the train hall, rushing to get their train. Or maybe you can get something out of your bag to read while you are waiting for the next train.
This is what I meant when I mentioned, 'relaxing trip' when traveling by train, in the previous message : reading a bit while listening to some music, watching people or enjoying the scenery. But some people don't seem to get this.
I maintain a website which hosts a forum, using popular forum software. This forum stores an md5-hash of the passwords of the users of this forum in a database. This website also has an admin section which is protected by a password. The passwords of the forum database are used to get access to the admin section. To do this the md5-hash of the submitted password is compared with the md5-hash stored in the database, exactly the same way as it is done by the forum software.
This week one of the users of the website reported to me that he was unable to access the admin section, but was still able to log in to the forum. The mechanism to check the password is identical for the admin section and the forum (as described in the previous paragraph), so at first I didn't understand why he couldn't access the admin section of the website. After some debugging I found out that the md5() function produced a different hash of the same password. It produced a correct hash, which was identical to the hash stored in the database, on the forum, but a different hash came up on the admin section.
I then remembered that the webserver (Apache 1.3) was upgraded a week earlier. The new webserver (Apache 2.0) uses a different default characterset (UTF-8), causing the website to work perfectly, but some special characters were replaced with question marks. This problem was solved by changing the characterset, in a .htaccess file in the directory of the forum, as the problem only occured there :
In .htaccess I added:
Only the forum used the old characterset, while the rest of the website, including the admin section, used the new default characterset of the webserver. Everything seemed to work fine.
Until this week, when that user couldn't access the admin section, while some other users still could login to the admin section. After some investigation I found out that the user that couldn't login used some special characters in his password. Then I started to realise that the md5() function must produce a different hash of the same string when it is encoded in a different characterset.
This makes perfect sense. In a lot of charactersets, normal alphanumeric characters (a-z, A-Z, 0-9) are in the same place, but some special characters like é or @, can have a different place in another characterset. When a string encoded in different charactersets contains special characters, it has a different value (on a binary/hexadecimal level). Thus when a hash is calculated of these strings, different hashes are produced.
Now that I understood what was happening I solved the problem by applying the same characterset to the entire website. The user who reported the problem was again able to login to the admin section.
The idea to go to Barcelona by train arose during a conversation during this winter. The plan was to go on a relaxing trip, both during the travel to Barcelona as during our stay there. We looked forward to do a bit of reading while driving by train and taking a peek every once in a while at the beautiful French landscape passing by.
We haven't made any arangements until now, but I just booked our train tickets so this means we are on our way in a few weeks time. Shortly after the examinations will have ended, we head for Barcelona.
Sunday, April 29, 2007
I came along a phrase on a blog of a friend:
For example, the linguistic, traditional truth of 'the sun rises' is in contradiction with the modern, contemporary notion of heliocentrism.
Although I understand what he means by this example, I think his conclusion is not entirely true.
The rising of the sun is an observation that is done by everyone on the surface of planet Earth. This observation does not contradict heliocentrism, because heliocentrism is a possible conclusion that can follow this observation. The real contradiction is between heliocentrism and another conclusion of the observer seeing the 'sun rise', known as geocentrism, the traditional view, ie. since the Middle Ages in our Western view of the world.
Traditionaly, the observation of the sun rising led to the conclusion that the sun must revolve around planet Earth.
Planet Earth was believed to be in the centre of the Universe, with the Sun, the Moon and all planets in our solar system revolving around it. Even the stars where placed in a circular band around planet Earth.
In the sixteenth century, Copernicus stated that this model was incorrect and should be replaced by a heliocentric model, where the Sun was placed in the centre of the solar system, with planet Earth and the planets revolving around the Sun. This theory was later refined by Johannes Kepler, who based his conclusions, known as the (3) laws of Kepler, on observations made by his tutor Tycho Brahe.
Copernicus and Kepler certainly came up with novell ideas, which contradicted the contemporary view (or even doctrine) of geocentrism. However, their views are certainly not new. In ancient times, long before any big civilisation was noted in the European parts of the world, Indian and Arab scientists were already familiar with a heliocentric model.
An observer, tied to the surface of planet Earth, seeing the sun rising in the morning, travelling through the sky all day, going down in the evening and disappear at dusk, until it rises again at dawn, could come to the conclusion that the sun revolves around planet Earth, if this observer believes that planet Earth is a fixed point in the Universe. With geocentric believes, this is a logical conclusion.
The same observer, also tied to the surface of planet Earth, sees the sun rising, but believes that it is planet Earth that revolves around the sun, as propagated in the heliocentric model, can explain this too. This observer might come to the conclusion that between moments he sees the sun rise, go down and rise again, planet Earth makes a complete revolution around the sun. We know this isn't true, as planet Earth revolves around its own axis, resulting in the day-night cycle of the sun rising. Actualy, the revolution of planet Earth around the sun defines a year, where different seasons (spring, summer, autumn and winter) cycle, instead of different parts of day (morning, afternoon, evening, night) caused by the axial revolution of planet Earth.
In both models, geocentric and heliocentric, an observer tied to the surface of planet Earth can see the sun rise, but depending on the applied model, he can explain it in another way.
The contradiction lies in the models being used and not between the observation and one of the derived models.
Thursday, April 26, 2007
Tuesday, April 17, 2007
According to a survey of French webmonitor XiTi, nearly 25% of all visits to websites in Europe is done with Firefox.
For Belgium, it is 18,7%, a little less than the European average. But this is still an increase of +1,4 (+8%) compared to last year's figures.
Sunday, April 01, 2007
Today I read a story on Slashdot about Google launching a free wireless broadband service, called TiSP. A link of how it works was provided, leading to a page on Google's website.
On this page was a picture of an installation kit and instructions on how to get your wireless network to work. Going short : You have to flush a cable through the toilet, into the sewage system and connect one end to a wireless accesspoint. The other end is picked up by a Google engineer, located somewhere in the sewage system, connecting it to a large and fast fiber optics network.
It sounds all very promissing and it is presented very professionaly, so it seems almost believable, but it is somewhat unrealistic and inpractical to flush a cable to get wireless internet access. Combine this with the date the story was released (april, 1st) :
This must be Google's April Fool's day joke. Very funny!
Friday, March 30, 2007
Sunday, March 18, 2007
Computers are good at calculating, searching through data and doing other automated tasks. And they're fast doing so. They're much faster than any human doing these tasks.
That's why computers are used for assisting human beings performing certain tasks or, in some cases even replace the human being.
But don't despair. There are some tasks a computer can't do. And that's when a human being is needed to help the computer.
A computer can't easily recognise objects shown in a picture, something a human being does without any problems or hesitation. If you show a picture of 'a car by a lake on a sunny day' to a human, he or she will tell you it's a picture of a car with a lake in the background. It seems to be nice that day, because of the blue sky and the small clouds.
If you present the same picture to a computer, depending on the complexity of the algorithm being used, you well get an answer like : large blue surface with green and red area's, or maybe (if it's a very strong or specialised algorithm) red car on blue background. The algorithm probably won't be able to tell the difference between the blue of the sky and the blue of the lake.
The same is true for recognising text. A human viewer will recognise a word or some characters without difficulty, even if the characters are deformed, written through and over each other or when the colour of the letters and the background change. Computers can detect characters and words, but only if it knows the used font, if the contrast between the characters and the background is big enough (and constant) and if the characters are nicely aligned. And even then it makes mistakes. When the conditions are a bit less ideal, a computer has a very hard time recognising characters or words. Most likely it will fail to recognise anything at all.
That's the reason why so called CAPTCHA's are used to make sure a human is performing a task on a website, like registering on a forum, leaving a message on a blog or logging into a bank-account : a computer can't read the word in the image.
This way, automated algorithms that are used to flood forums with spam, are stopped (or delayed, as the algorithms to read captcha's are getting better).
But most of the time, computers (algorithms) are unable to recognise things a human does without effort. And that's were the human can help the computer. Computers are good at looking up information that's stored in a database. So if a database would be constructed linking the picture of the car with some keywords like 'car, blye sky, sunny day, lake, ...' the computer would 'know' what is on the picture. If the computer was asked to present a picture of a 'car' or even of 'car by a lake' it would filter through the database and come up with the picture of 'the car by the lake on a sunny day'.
A computer couldn't fill the database with keyword matching data, because it is unable to recognise what's on the picture, but a human could. Of course, it would be a very tedious task for a human being to look at every existing picture and tagging it with keywords. That's why a scientists came up with the idea to turn it into some sort of a game.
The concept is easy : two randomly picked people are paired and they are presented some pictures. They have to describe what's on the picture, using keywords or tags. If both people come up with the same keyword, they are granted some points and the next image is presented. The goal is to earn as much points, i.e. get as many matching keywords as possible, in a defined timeframe. The best scores are added to a highscore list.
The concept is simple, but effective. Google is using this 'game' to tag pictures found on the web, in order to return the best matching search results for images.
So, for now computers still need human assistance to perform certain tasks, like recognising characters, text, images or every day objects or understanding what a text or conversation is about. But maybe some day, computers could pass the Turing Test, and they would be able to 'recognise', 'understand' and maybe 'think' like humans do. But it seems that computing and Artificial Intelligence have a long way to go to be able to do that. Until then, computers still need help.
Monday, March 12, 2007
This weekend I rediscovered something I haven't felt for quite some time now : I was very excited solving a mathematical problem. I was so excited, I lost track of time. It was after a few hours I realized I had been busy looking into the problem and looking up some stuff, without taking a break.
Last few years, most of the time when I'm studying or getting some work done, I get distracted after a time and I take a break or do something relaxing. Most difficult part is to stop taking a break and start studying again. And sometimes I'm taking more and longer breaks than that I spent time studying.
I haven't solved the particular problem yet, I have to look into it some more, but I'm eager to continue working on the problem and finding a solution.
I'm very glad I found this drive to solve problems again. I thought that I lost it, but now that I got it back again, I'm looking forward on digging into some more mathematical and physics problems.
I can't realy describe what it feels like to have found that drive again, but it feels very good. And I like it a lot!
Thursday, February 22, 2007
Tomorrow is my birthday and I'm throwing a party to celebrate.
All preperations have been made, invitations have been sent and I have notified my neighbours.
About 15 people will attend, at least, that's the number of people I've invited.
Today I went shopping to get drinks and snacks. I had to carry my groceries home by foot, so I went to shop two times to get everything I needed.
This is what I got:
- 24 cans of beer
- 3 l of white wine
- 3 x two liter bottles of coke
- 2 l of orange juice
- 1 bottle of Ice Tea (I wanted to bring two, but the one I got was the only one left in the shop)
- 4 bags of differently flavoured crisps
- 2 bags of party nuts
- some hot snacks (at the moment I bought them, they were frozen. I will have to fry them or put them in the oven before serving them to my guests)
All drinks are in the fridge, so they will be cool by the time they will be served.
The only thing that has to be done is to move some furniture around.
I almost forgot, I have to buy some disposable cups tomorrow.
The only casualty so far is one can of beer, which was attracted by earth's gravitational force. In other words: I dropped it when taking it out of it's wrapping, before putting it in the fridge. The fall caused the tin foil to shear, so I almost got a beer shower.
Everything is ready for a nice party. Now, only my guests have to show up. Let's hope they do. ;-)
Thursday, February 08, 2007
I remember a statement recently made by a fellow student and friend, claiming that 'knitting is hip' and will soon become the next big thing. Time will tell if she's proven right.
Anyway, it seems more people are knitting and are making useful things with it. I came across an article about a maths professor who is using crocheting to make models of mathematical objects that are difficult to imagine, like hyperbolic planes and a Lorenz manifold.
Sunday, January 28, 2007
Sunday, January 14, 2007
Tomorrow at this time the first part of my first exam will come to an end. Hopefully I will be able to fill out the right answers. I've been preparing for this exam for the last three weeks and feel like I know some of it, but it's a very hard course.
Nearly 200 pages full of mathematical formulas and principals, including proof of all statements that are made. On average there is a statement with proof on every page throughout the whole textbook. This means a little less than 200 statements with proof that I must be able to reproduce tomorrow.
Although I feel confident I will be able to produce some of the most important ones, I'm not sure about a whole lot of other statements.
Unfortunately the exam consists of two parts. The theoretical part is tomorrow in the afternoon, the second part consist of excercises and is scheduled the day after in the morning. It is a good thing to have some time between both parts, where I can review some excercises. But it's also a very long time where pressure will start build.
With less than 24 hours to go I'm going to review the most important statements again, in order to be prepared as good as possible.
An explanation for the formation of ball lightning was found by New Zealand researchers.
"Ball lightning forms when lightning strikes soil, turning any silica in the soil into pure silicon vapor. As the vapor cools, the silicon condenses into a floating aerosol bound into a ball by charges that gather on its surface, and it glows with the heat of silicon recombining with oxygen."
To prove the theory, a Brazilian research team set up a test, which resulted in small ball lightning the size of pingpong balls.
Friday, January 12, 2007
Famous American university MIT, Massachusetts Institute of Technology, has made its courses available on the internet for free. This is part of the OpenCourseWare program they are participating in.
MIT wants to make their knowledge available to everyone, including those who can't afford to study at a big university. A lot of courses are already available at the moment. In the future all MIT courses will be available through the program.