Things I've learned from my students

One thing I've learned this year whilst teaching at the University is that, apparently, the probability of having a hard disk failure on your computer is tightly linked to work assignments deadlines.

Let me explain how I reached this conclusion. I teach "Introduction to Programming" and at the end of the semester, the students have to deliver a work assignment. Usually, they have to develop a game in Java and this semester the decision was to implement a simple text-based Minesweeper.

Interestingly, as the deadline was becoming closer, the number of students that come up to me with an excuse to try and get an extension was massively increasing. But the amazing part is the fact that most students used the same excuse: hard disk failure that led to loss of work.

Since all students are honest and could never lie to a professor just to try to get an advantage over their colleagues (let's be naive about it) I can empirically conclude that the following applies:


Needless to say, this didn't change my position and no extensions were given.
It's Murphy's law :-)

0.999... = 1

Did you know that 0.9999... is equal to 1? Don't believe me? See some proofs here.

So many new world records in Olympic swimming...isn't that a bit suspicious?

I told you that this idea of having Olympic swimmers wear special bathing suits would have quite an impact. Now, the Australia swimming team has beaten the previous world record for 4x200m freestyle with a difference of more than 5 seconds!! Is it a coincidence that ALL of them wore the same special bathing suit? I don't think so.

The only alternative that I see, is that the Chinese organization was wrong while measuring the Olympic pool and it is in fact smaller than it should. Well, it wouldn't be such a surprise if they did this on purpose. Considering that they used pre-recorded songs and virtual fireworks in the open cerimony, I wouldn't be surprised if they did this to bring some extra attention to the Olympic Games in Beijing!! Everything to post a good image of China to the World...

The key to my heart

The heart has ways that the mind can only wonder and maybe that's why most of the times it's difficult to understand people, in general. Especially women. But it look's like someone has found the "function" of the heart:

Don't believe me? Here's the result:

More romantic mathematics here...

The first Olympic sprinter without legs

I'd like to think that my previous post on this subject somehow contributed to the recent decision of letting Oscar Pistorius qualify to the Olympics, but I'm not that naive :-)

But it's good to see that not everybody is as unreasonable as the International Association of Athletics Federations. The Court of Arbitration for Sport finally accepted that there is no difference between a double-amputee sprinter that uses a set of prosthetic legs and the Speedo-sponsored swimmers that use the Speedo LZR Racer Suit to get an aerodynamic advantage over their adversaries.

It may be the case that Oscar Pistorius doesn't even qualify to the Olympics, but at least he wasn't discriminated for being handicapped.

Let's see how the story evolves...

Another interesting problem: crossing the bridge

Every once in a while I like to propose some interesting problems, and this one certainly fits the profile:

• Four friends need to cross a bridge
• A maximum of two people can cross the bridge at the same time
• It's night and it's very dark, so they use the only lamp they have, to see the way
• Each pair can only cross the bridge at the rate of the slower person (each person's crossing rate is given by the number showed on top of each person)
• Try to make them all cross the bridge in a total of 17 minutes

Yes, 17 minutes. It is possible! Here's a snapshot of the result...just to tease you :-)

If you got 21...that's not bad! That's the second fastest solution. But 17 is still possible and it's the fastest solution. If you really want to cheat know the solution check out this picture that's hiding the solution.

Technology to beat World/Olympic records...but only for swimmers

The Speedo LZR Racer Suit is a ultra-lightweight and water-repellent swimming suit that gives shark-like swimming capabilities to athletes. It reduces the drag effect and skin resistance of the swimmer's body, allowing him/her to gain those milliseconds that could make a difference when beating World/Olympic records.

An in fact, this swimsuit really gives athletes that extra boost they need. 36 of the 39 world records that were beaten since last February were achieved by athletes with this swimsuit from Speedo. This clearly states that an athlete with this particular swimsuit has an advantage over other athletes.

Doesn't this sends out the wrong message to the sporting community? At this rate, world records will only be beaten by the athletes that are lucky enough to be sponsored by these companies.

But, even though some controversy exists around this issue, nothing is done to stop swimmers from using the special-purposed suits.

This kind of reminds me of a similar situation that had a completely different outcome. Oscar Pistorius, a double-amputee paralympic runner that is only able to run through the use of a prosthetic device (a set of carbon fibre transtibial artificial limbs), wanted to participate in the able-bodied competitions (for people with no handicaps or disabilities). 

However, his artificial legs generated claims that he had an unfair advantage over able-bodied runners. And because the rules clearly state that an athlete using a device cannot have an "advantage over another athlete not using such a device", he was ruled ineligible for competitions.

I don't think this decision was wrong but some questions remain: why was this particular athlete unable to participate in a competition? Why isn't the same rule applied to swimmers? Shouldn't all enhancing devices be forbidden from sporting competitions? Or at least shouldn't ALL athletes be given the opportunity to use the same equipment so as to really boost the competition level?

An interesting problem: part 2

So, did you think about an answer for the problem I suggested earlier?



To recap: Imagine you're on a game show and you are asked to choose from one of three doors. In one door, there's a prize (a beautiful car) and on the other two doors, there is a goat on each door. After you choose the door, the game show host will show where one of the goats is from the remaining two doors (remember there are two goats to start with, which means that no matter which door you choose, there will always be at least another goat on the doors that you didn't choose). In addition to showing you where one of the goats is, the game show host gives you the opportunity to swap between the original door that you chose and the remaining door.

So, faced with this decision what would you do? Would you stick with your initial decision? Or would you swap doors? At first, this seems to be an irrelevant choice, right? Well, think again...

By the way, this is called the Monty Hall Problem.

Watch this video of the popular television show Numb3rs to help you with the answer:



If you still need a clearer explanation, check out the following video:



And if you're still not convinced, then use the following programs that I created (in Java) to test this theory:

Monty Hall Problem (No Swapping) - Source
Monty Hall Problem (Swapping) - Source

These programs perform this test 100 million times each, where the first option doesn't swap the initial choice and the second does.

Surprise, surprise, here are the results that I obtained:

• No Swapping: The program got it right 33% of the time.
• Swapping: The program got it right 66% of the time.

Usually, the Random generator of a computer is not really a reliable random generator, but even if you try this test yourself (with cards or some other objects) you'll obtain similar results.

So, always remember to swap your choices :-)

An interesting problem: part 1

Imagine you're on a game show and you are asked to choose from one of three doors. In one door, there's a prize (a beautiful car) and on the other two doors, there is a goat on each door.


After you choose the door, the game show host will show where one of the goats is from the remaining two doors (remember there are two goats to start with, which means that no matter which door you choose, there will always be at least another goat on the doors that you didn't choose). In addition to showing you where one of the goats is, the game show host gives you the opportunity to swap between the original door that you chose and the remaining door.


So, faced with this decision what would you do? Would you stick with your initial decision? Or would you swap doors?

Think about it for a while. I will post the solution (UPDATE: check here) and hopefully some interesting results from a simulation soon :-)

The Wii workout...at the gym!!

That's right...at the gym!! Remember when I posted on the "Wii before-and-after"? Well, now some gym in Canada felt it was a good idea to allow their clients to do some exercise while playing Wii Sports.


In Reuters:

"Studeo 55 in Vancouver has incorporated a Nintendo Wii workout station into circuit training where users can punch, run and jump with the system's movement-sensitive controller. Nathan Mellalieu, the owner of Studeo 55, said he decided to bring video games into a fitness environment after watching how much fun some children were having and, more importantly, seeing them sweating."

"All of our clients get great results, but the biggest result we see is the smile on their faces. People have to understand that fun is important."

VirtuSphere: the new platform for immersing in virtual reality

VirtuSphere is a new idea for creating virtual reality fully-accessible worlds without the limitations of a room with obstacles.

On their own words:
The VirtuSphere platform consists of a large hollow sphere that sits on top of a base and allows the sphere to rotate 360 degrees. Wearing a wireless, head-mounted display, users can step inside the sphere to fully interact in immersive virtual environments. The VirtuSphere enables 6 degrees of freedom – one can move in any direction; walk, jump, roll, crawl, run over virtually unlimited distances without encountering real-world physical obstacles.

So, it's easy to perceive the advantages of such technology and how/where it can be used:

• Military, law enforcement, dangerous occupations – safe training, simulation and mission rehearsal
• Health, exercise, sport – fitness clubs; bridge between classical and cyber games
• Entertainment market
• Education, museums
• Architecture, construction, real-estate – site model walk-troughs
• Virtual travel and tourism
• Home gaming and exercise

Source: VirtuSphere

Water-proof MP3 Players

Who said you can't use your MP3 player on the bath or when you go out for a swim? SwimMan's new version of the iPod Shuffle (image on the left) allows you to use it anywhere in the water up to 10 feet (more or less 3 meters). You can even wear it in the shower, assuming you can find something to clip it to.

But if you're more of a swimmer and you don't like to have things clipped somewhere, you can always try to use the Century's Dolphin water-proof MP3 Player (image on the right).

Inside, the Dolphin packs 1GB of flash, USB 2.0, and support for MP3/WMA playback off 8-hour battery. Looks aside, at ¥12,800 (about $107 or 81€) -- which includes a pair of unusually decent looking waterproof headphones -- it'll save you a healthy chunk-o-change compared to the $250 (190€) SwimMan's iPod Shuffle.

Source and photos: Engadget

The Nintendo Wii's "Before and After"

As I posted last November, Nintendo's Wii is good for exercising. But now, some proof is starting to come up. Check out Mickey's results:


Mickey DeLorenzo, a 25-year-old living in Philadelphia, decided to run an experiment for six whole weeks, and while he sought to keep his eating habits constant, he devoted 30 minutes per day to Wii Sports and monitored his weight, calories burned per session, body fat percentage and heart rate.

Mickey started out at 182 pounds, and after a month and a half of Wii workouts, managed to take his weight down to 172 pounds.

So, looking for a diet? Buy the new Nintendo Wii's Diet Program Pack...

Source and images: Engadget