Thursday, July 02, 2009

Race for the Galaxy

Sometimes you come across a game you really like. Recently I came across Race for the Galaxy by designer Tom Lehmann. This card game has many interesting aspects. There is a big element of luck which makes the game fun for everyone, even without much knowledge about the game you can score well. But, at the same time skill play a significant role, actually to such an extent that an experienced player would win with high frequency. The game mechanics also makes the game distinguish itself from the competition. Simultaneous action is used. This make the game flow very fast as players feel they are involved all the time.

The nice space theme is also very tastefully carried over to the art on the cards. Don't be daunted by all the symbols, they are cleverly designed , once you get their meaning you never have to check the rules again.

Another good thing is that the game can be played in multiplayer mode without getting the frustrating feeling that your nicely crafted strategy is muted by an inexperienced player. The interaction between the players is very intricate. This is an effect of the hidden action choosing mechanism. You have to choose your actions for each round in such a way as it benefits you but not the other players. The most obvious action for you could be just too beneficial for the others depending on their cards so you just have to choose something else and hoping to be able to leach of the others choices.

Finding players to play with could be tough but recently this online site that offers good games has come to life. Here you can familiarize yourself with the game in solo mode and then try your skills with people from all over the world just from within your browser. Happy gaming.

Wednesday, March 28, 2007

Zimmerman programming contest

For you programmers that have some time to spare and a keen interest in tweaking your code here is the site for you. Programmers all over the world compete in writing programs that solves a certain problem. The really nice thing about these contests is that the problems chosen for the contests are carefully configured to be accessible to many people of all skills. Often a solution to a problem is very easy to find but to find a good solution is really hard. Also the contest runs over many days so you have ample time to write your code. When you think you have a good program you can start submitting solutions and you will get immediate feedback on how good your program really is. The feedback from your first submissions will often send you back to the drawing board trying to come up with a better algorithm. This is very good practice for programmers in general and I heartily recommend it. Happy crunching!

Thursday, December 21, 2006

Who latched the door?

Here comes a little criminal sleuthing piece for you to think about during Christmas. Ten years ago something gruesome happend in Boulder, Colorado. Six year old JonBenet Ramsey was found dead on Christmas the 26/12-96 in the basement of her home. Please read the full background of the story here as I will only tell you about a small piece of the puzzle which I think has been overlooked through the years. The whole case is very strange, invloving things like the strangest ransom note ever and a very strange crimescene.

JonBenet was found in a room in the basement called the wine cellar. It was not used by the family for storing wine but more a kind of a storage room. This room was windowless and dark and the only entrance to the room was a wooden door. The interesting thing about this door was that it had a small wooden latch fitted at the top of the door. As the door was opening outwards the latch had no real use other than to keep the children out of the room when it was used for storing Christmas presents. Now, when the first oficer arrived at the house the winecellar door was latched. This led him not to search the room as he was securing the house for a possible intruder still lurking in the house. The latch told him that no intruder was in that room as it was latched from the outside. Later in the day the father did a search of his own and found the door still latched. He open it in found JonBenet on the floor. Assuming that it was the killer who placed JonBenet in the wine cellar he/she must have latched the door behind him/her. Think about it, who would be in the state of mind to latch this door?

An intruder would not only have to know about the latch but would also have to consciously latch it. As the latch didn't have any real use why would he. During later interviews the father expresses his astonishment that he found the door latched when he was looking for JonBenet. He even states that he was so surprised that the door knob slid out of his hand when he pulled on it the first time, then realizing that the door was latched. The mother said when interviewed that she sometimes latched the door. She did it during Christmas when she used the room to hide Christmas presents from the children and didn't want them to enter the room.

You can see the latch on the top left of the door in the picture.

Friday, October 20, 2006

The Baldwin Effect

Often in nature there seem to be a connection between learning and evolution. Some traits that are inherited today seem to first have been passed from parent to child by learning. First it was thought that genes actually could change as the result of learning, this is called Lamarckism, today we know this is not the case. The genes are the same through the life of an organism.

So how does it happen that learnt traits can enter the genome. It is really not that strange. If a behaviour starts to spread among a group of individuals and parents teach this behaviour to their children those children more adept at that behaviour will have a slight advantage. This is called the Baldwin effect.

This is interesting because when designing an evolutionary algorithm this should be accounted for. Introducing learning and teaching could have beneficial effects on the fitness landscape. The fitness of an organism should not be calculated on the genes but on the phenotype. Allowing the phenotype to change, by learning or by physically adapting, during it's life allows the genes to express their potential. The genes can be more general in their expression, you don't need a gene that says 'this creature climb trees' but instead say 'this creature is agile', 'this creature is strong' and 'this creature has claws'. The tree climbing part is part of the behaviour that is passed by learning and the physical traits increases the ability to fulfill that behaviour.

Introducing a phenotype gives other benefits. You want the genes to behave well during crossover but at the same time you want a fitness to be calculated from the genes in an easy way. Crossover works best when genes that cooperate is close in the genome. They want to get passed as a bundle. So allowing genes to be able to move within the genome, called transposition and occurs in real cells during recombination, allows genes that cooperate to move together and so increasing the chance that they will get passed together. And when you allow genes to move around it is often beneficial to introduce the concept of a phenotype that is easier to use for matching the organisms against each other.

Friday, October 13, 2006

Stirling meets Wankel

I have already talked about the Wankel engine. The beauty of one rotor spinning in the same direction all the time. The Wankel engine normally works by combustion though. This makes a quite inefficient use of fuel as the fuel doesn't burn optimally during combustion. The Wankel construction further worsens this by the shape of the combustion chamber, making Wankel engines consume even more fuel than their crank engine counterparts.

But there exist a different type of engine that makes much better use of the fuel. I am thinking about the Stirling engine or air engine as it was called by Stirling himself when he invented it 1816. This engine works by converting a temperature difference into rotational enegy. The basic principle is that a gas that is heated expands and a gas that is compressed increases in temperature. One part of the engine is hot and the other cold. Gas is expanded in the hot part and decompressed in the cold part. This construction usually make Stirling engines quite large as they need big cooling radiators.

The Wankel engine's drawback regarding fuel consumption and the bulkiness of the Stirling can maybe be overcome by combining them. We may not see Stirling engines in cars as the sole provider of energy but it could be used when acceleration is not needed. During constant speed on the highway for example. Stirlings have been used to great success in submarines where their quiet running and less need of oxygen is great benefits.

Some work has been done to fuse these two designs together. The QuasiTurbine and the Trochilic engine are good examples how the future may look like. I think there is much more to do in this field.

Monday, October 09, 2006

Wriggling on a hook

A worm of unit length is caught on a hook. He can only move in the plane i.e not in three dimensions. He can not exert any momentum against the hook which means that his center of gravity always will be on the vertical line from the hanging point to the ground. Suppose now he wriggles around as much as he can.

What is the area covered by the worm during his wriggling?

A value for the area and a short description of how you found it will suffice as an answer. Solve this puzzle and you will enter the "Fields of Gold" hall of fame together with Pooh (who solved the first cornfield puzzle and the fuse burning puzzle) and future master puzzle solvers.

Saturday, October 07, 2006

Male and Female Issues

When two singles decides to move in together in a new apartment they usually have to decide who's stuff goes were. Who's TV are we going to use, who's dinner table and so on. Some of the stuff got to go to the landfill. Two hard heads may never be able to decide, they just love their stuff too much.

Funny thing is that solving that problem may just have been the cause of it! Bear with me, that sentence will clear up in a moment.

The first cells with cytoplasmic genes(genes not in the nucleus), had to solve exactly this problem,who's mitochondria are we going to use when we merge. Both cells are very eager to share and recombine their nucleus but what to do with the stuff that comes along.

The solution to this problem may very well be the introduction of gender. The female brings the cytoplasmic genes and the male has to ditch his. This is very plausible because there is a huge cost for having two or more genders. Having several genders means that you have to find a suitable partner when you want to have kids. Just mating with anyone would sure be easier. From an evolutionary perspective gender makes it harder to pass on the genes. There must be a huge benefit, and that may very well be the ability to have symbionts inside the cell.