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Genetic Algorithms

Warning. This post has absolutely nothing to do with SQL Server.

What are Genetic Algorithms?

Genetic algorithms are a form of evolutionary computation, a branch of artificial intelligence that focuses on evolving effective or optimal solutions to difficult problems, based on the biological theory of evolution.

Genetic algorithms are, at their core, a search/optimisation technique. They are a way of finding maximum/minimum solutions to problems and, can be effective when there is no algorithmic solution to the problem. An example here would be the ‘Travelling Salesman’ problem.

Genetic algorithms work by taking an initial population of potential solutions (referred to as individuals), selecting a subset of the population that has the highest fitness then using that subset to generate a second generation. From the second generation again a subset with the highest fitness is selected and used to generate a third generation. This repeats until either the ‘fittest’ individual is considered a good enough solution, or until a certain number of generations have passed.

There are advantage to using genetic algorithms to solve problems over more traditional methods like hill climbing.

  • Genetic algorithms can quickly produce good solutions though they may take a lot of time to find the best solution. This is a benefit when the problem is such that the absolute best solution is not necessary, just one that is ‘good enough’
  • They are not susceptible to getting trapped by local maxima.
  • They do not work on the entire search space one potential solution at a time, but rather work on populations of potential solutions, focusing towards more optimal areas of the search space.

A genetic algorithm will almost always find an optimal solution, given enough time. The main downside is that they may take a lot of time to find that optimal solution.

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Stepping down

Sunday saw the last game (for now) of the d20 Modern campaign I’m running. I’m going to miss DMing, but it was for the best. I’m struggling with a bit of burnout and a lack of free time.

The campaign went quite well. The players seemed to enjoy it and that’s the only real measure of any importance. We didn’t get quite as far as I had hoped, but a lot of hints and clues were dropped during the various adventures and I think that all the players have a better idea of the ‘big picture’. They’ve also managed to disrupt the big bad guy’s plans often enough to be irritating.

For the next few months at least, we’ll be playing high-fantasy D&D as we return to the world of Per-rune. Currently our characters are about to disembark ship after a rather exciting trip to the Elven kingdom. All we need is to do some shopping for winter gear and then head inland back to the small town of Kurat, where the whole thing started. Easy, right?

Birthday musings

Another year gone, another year older. It’s been an interesting year.

Professionally, I’m very happy with the past year. I’ve achieved several goals, got to know some interesting people in the SQL community and, of course, started this blog. I’ve also made some fairly important decisions about the future.

Academically, I’m not so happy. My masters thesis is behind where it should be. (a fact I’m sure my supervisor would agree with.) Most of the initial reading is done and I know what I need to do. I need to sit down and get busy. This is going to have to take a higher priority in the next few months.

On more personal matters, a good friend moved up to JHB. It’s very good to see her again. The roleplaying campaign is going well and from the feedback I’ve been having, the players are all enjoying themselves.

Overall, it’s been a good year. Here’s to the next one.

On a haunted house

The second session of the haunted house adventure went down far better than I could have ever hoped. In fact, the players asked to stay late so that they could finish it, they were having so much fun.

They survived the haunted house and uncovered the reason behind all the strange occurrences. they couldn’t prevent a thug from making off with the knife that had been the focus of all the strange events, but that’s fine. It adds possibilities for the future.

Everyone was enthusiastic, interested and most importantly, involved in the story. I’m still on a bit of a buzz from the game and I’m very psyched for the campaign.

Next up, depending on the players, either investigating the happenings at the cathedral, visiting a museum exhibit, or attending the cultural festival.

Back in the GM chair

This last sunday saw me taking back the GM chair for the group that I play with. For the past year we’ve been playing my friend Phillip’s Per-rune game. (details and an in-character journal on my web site)

My campaign is a modern day supernatural game, a bit like Buffy, but darker. It’s set in the historical city of Oxford, in England, in the year 2002. More details are available on the campaign web site. The pages aren’t finished, there’s a lot of links that go no where.

All in all, the game went off without a hitch. Lots of admin-type stuff to start, reminders of clues, shopping, etc, etc but less than I expected.

Now let’s see if the characters can unravel the mysteries of a haunted house, and if they can survive to tell the tale.

I’ll probably comment here occationally on on significant bits of the campaign as they happen.