Indoor positioning of a moving object in 3D space - algorithm

I am working on a project which determines the indoor position of an object which moves in 3D space (e.g. a quadcopter).
I have built some prototypes which use a combination of gyroscope, accelerometer and compass. However the results were far from being satisfactory, especially related to the moved distance, which I calculated using the accelerometer. Determining the orientation using a fusion of gyroscope and compass was close to perfect.
In my opinion I am missing some more sensors to get some acceptable results. Which additional sensors would I need for my purpose? I was thinking about adding one or more infrared cameras/distance sensors. I have never worked with such sensors and I am not sure which sensor would lead to better results.
I appreciate any suggestions, ideas and experiences.

The distance checking would decidedly help. The whole algorithm of any surface geo survey is based on the conception of start/final check. You know the start, then you add erroneous steps, and come to the finish that you know, too. But you have collected some sum error by the way. Then you distribute the error found among all steps done, with the opposite sign, of course.
What is interesting, in most cases you not only somewhat diminish the effect of arbitrary mistakes, but almost eliminate the systematical ones. Because they mostly are linear or close to linear and such linear distribution of found error will simply kill them.
That is only the illustration idea. Any non-primitive task will contain collecting all data and finding their dependencies, linearizing them and creating parametrical or correlational systems of equations. The solving of them you get the optimal changes in the measured values. By parametrical method you can also easily find approximate errors of these new values.
The utmost base of these methods is the lesser squares method of Gauss. The more concrete methodics can be found in old books on geodesy/geomatic/triangulation/ geodesy nets. The books after introduction of GPS are for nothing, because everything was terribly simplified by it. Look for the books with matrix formulaes for lesser squares solutions.
Sorry if I had translated some terms into English with errors.

Related

When should these methods be used to calculate blob orientation?

In image processing, each of the following methods can be used to get the orientation of a blob region:
Using second order central moments
Using PCA to find the axis
Using distance transform to get the skeleton and axis
Other techniques, like fitting the contour of the region with an ellipse.
When should I consider using a specific method? How do they compare, in terms of accuracy and performance?
I'll give you a vague general answer, and I'm sure others will give you more details. This issue comes up all the time in image processing. There are N ways to solve my problem, which one should I use? The answer is, start with the simplest one that you understand the best. For most people, that's probably 1 or 2 in your example. In most cases, they will be nearly identical and sufficient. If for some reason the techniques don't work on your data, you have now learned for yourself, a case where the techniques fail. Now, you need to start exploring other techniques. This is where the hard work comes in, in being a image processing practitioner. There are no silver bullets, there's a grab bag of techniques that work in specific contexts, which you have to learn and figure out. When you learn this for yourself, you will become god like among your peers.
For this specific example, if your data is roughly ellipsoidal, all these techniques will be similar results. As your data moves away from ellipsoidal, (say spider like) the PCA/Second order moments / contours will start to give poor results. The skeleton approaches become more robust, but mapping a complex skeleton to a single axis / orientation can become a very difficult problem, and may require more apriori knowledge about the blob.

Search space data

I was wondering if anyone knew of a source which provides 2D model search spaces to test a GA against. I believe i read a while ago that there are a bunch of standard search spaces which are typically used when evaluating these type of algorithms.
If not, is it just a case of randomly generating this data yourself each time?
Edit: View from above and from the side.
The search space is completely dependent on your problem. The idea of a genetic algorithm being that modify the "genome" of a population of individuals to create the next generation, measure the fitness of the new generation and modify the genomes again with some randomness thrown is to try to prevent getting stuck in local minima. The search space however is completely determined by what you have in your genome, which in turn in completely determined by what the problem is.
There might be standard search spaces (i.e. genomes) that have been found to work well for particular problems (I haven't heard of any) but usually the hardest part in using GAs is defining what you have in your genome and how it is allowed to mutate. The usefulness comes from the fact that you don't have to explicitly declare all the values for the different variables for the model, but you can find good values (not necessarily the best ones though) using a more or less blind search.
EXAMPLE
One example used quite heavily is the evolved radio antenna (Wikipedia). The aim is to find a configuration for a radio antenna such that the antenna itself is as small and lightweight as possible, with the restriction that is has to respond to certain frequencies and have low noise and so on.
So you would build your genome specifying
the number of wires to use
the number of bends in each wire
the angle of each bend
maybe the distance of each bend from the base
(something else, I don't know what)
run your GA, see what comes out the other end, analyse why it didn't work. GAs have a habit of producing results you didn't expect because of bugs in the simulation. Anyhow, you discover that maybe the genome has to encode the number of bends individually for each of the wires in the antenna, meaning that the antenna isn't going to be symmetric. So you put that in your genome and run the thing again. Simulating stuff that needs to work in the physical world is usually the most expensive because at some point you have to test the indivudal(s) in the real world.
There's a reasonable tutorial of genetic algorithms here with some useful examples about different encoding schemes for the genome.
One final point, when people say that GAs are simple and easy to implement, they mean that the framework around the GA (generating a new population, evaluating fitness etc.) is simple. What usually is not said is that setting up a GA for a real problem is very difficult and usually requires a lot of trial and error because coming up with an encoding scheme that works well is not simple for complex problems. The best way to start is to start simple and make things more complex as you go along. You can of course make another GA to come with the encoding for first GA :).
There are several standard benchmark problems out there.
BBOB (Black Box Optimization Benchmarks) -- have been used in recent years as part of a continuous optimization competition
DeJong functions -- pretty old, and really too easy for most practical purposes these days. Useful for debugging perhaps.
ZDT/DTLZ multiobjective functions -- multi-objective optimization problems, but you could scalarize them yourself I suppose.
Many others

Accurate parallel swathing algorithm for (GPS) guidance needed

I wrote a delphi program generating a gpx file as input for a "poor man's guidance system" for aerial spray by means of ultralight plane.
By and large, it produces route (parallel swaths) using gpx file as output.
The route's engine is based on the "Vincenty" algorithm which works fine for any wgs84 computation but
I can't get the accuracy of grid generated by ExpertGPS of Topografix (requirement).
I assume a 2D computation on the ellipsoïd :
1) From the start rtept (route point), compute the next rtept given a bearing and an arbitrary distance (swath length).
2) Compute the next rtept respective respective to previous bearing (90° turn) and another arbitrary distance (swath distance).
3) Redo 1) with the last rtept as starting point but in the opposite direction, and so on.
What's wrong with it ?
You do not describe your Pascal implementation of Vincenty's earth ellipsoid model so the following is speculation:
The model makes use of numerous geometrical trig functions-- ATAN2,
COS, SIN etc. Depending whether you use internal Delphi functions
or your own versions, there is the possibility of lack of precision
in calculations. The precision in the value of pi used in your
calculations could affect the precision you require.
Floating point arithmetic can cause decimal place errors. It will
make a difference whether you use single, double or real. I
believe some of the internal Delphi functions have changed with
different versions so possibly the version of Delphi you are
using will affect how the internal function is implemented.
If implemented accurately, Vincenty’s formula is supposed to be
accurate to within 0.5mm. Amazing accuracy. If there are rounding
errors or lack of precision in your Delphi implemention, the positional
errors can be significantly larger.
Consider the accuracy of your GPS information. Depending on how
many satellites are being used by the GPS receiver at any one time,
the accuracy of the positional information changes. Errors on
the order of 50 feet or more is possible. Additionally, the refresh
of positional information on the GPS receiver is not necessarily
instantaneous; therefore if the swath 'turns' occur rapidly, you
will have to ensure the GPS has updated at the turning point.
Your procedure to calculate the pattern seems reasonable so look
at your implementation of Vincenty's algorithm in your Delphi code.
This list is not exhaustive, I imagine others can improve it
dramatically. What I mention is based on my experience with GPS and
various versions of Delphi and what I could recall off the top of my head.
Something you might try is compare your calculations of
distance/bearing using your implementation of the algorithm with
examples provided on the Internet. There are several online
calculators. If you have not been there, the Aviation Formulary
is an excellent place to find examples of other navigational tricks.
http://williams.best.vwh.net/avform.htm . A comparison will
allow you to gain confidence in the precision of the Delphi
implementation of Vincenty's algorithm with data calculated by
mathematicians. Simply, your implementation of Vincenty may not be
precise. Then again, the error may be elsewhere.
I am doing farm GPS guidance similar for ground rig just with Android. Great for second tractor to help follow previous A B tracks especially when they disappear for a bit .
GPS accuracy repeat ability from one day to next will give larger distance. Expensive system's use dGPS2cm-10cm.5-30metres different without dGPS. Simple solution is recalibrate at known location. Cheaper light bars use this method.
Drift As above except relates to movement during job. Mostly unnoticeable <20cm 3hrs. Can jump 1-2metres rarely. I think when satellite connect or disconnect. Again recalibrate regularly at known coordinates ,i.e. spray fill point
GPS accuracy. Most phone update speed 1hz. 3? seconds between fixes at say 50km/hr , 41.66m between fixes. On ground rig 18km hrs but will be tracks after first run. Try a Bluetooth GPS 10hz check update speed and as mentioned fast turns a problem.
Accuracy of inputs and whether your guidance uses dGPS will make huge difference.
Once you are off your line say 5 metres at 100metres till next point, then at 50 metres your still 2.5 metres off unless your guidance takes you back to the route not the next coordinates.
I am not using Vincenty as I can 'bump'back onto line manually and over 1km across difference <30cm according to only reference I saw however I am taking 2 points and create parrallel points across.
Hope these ideas help your situation.

How would you implement a perfect line-of-sight algorithm?

Disclaimer: I'm not actually trying to make one I'm just curious as to how it could be done.
When I say "Most Accurate" I include the basics
wall
distance
light levels
and the more complicated
Dust in Atmosphere
rain, sleet, snow
clouds
vegetation
smoke
fire
If I were to want to program this, what resources should I look into and what things should I watch out for?
Also, are there any relevant books on the theory behind line of sight including all these variables?
I personally don't know too much about this topic but a quick couple of Google searches turns up some formal papers that contain some very relevant information:
http://www.tecgraf.puc-rio.br/publications/artigo_1999_efficient_lineofsight_algorithms.pdf - Provides a detailed description of two different methods of efficiently performing an LOS calculation, along with issues involved
http://www.agc.army.mil/operations/programs/LOS/LOS%20Compendium.doc - This one aims to maintain "a current list of unique LOS algorithms"; it has a section listing quite a few and describing them in detail with a focus on military applications.
Hope this helps!
Typically, one represents the world as a set of volumes of space held in some kind of space partitioning data structure, then intersects the ray representing your "line of sight" with that structure to find the set of objects it hits; these are then walked in order from ray origin to determine the overall result. Reflective objects cause further rays to be fired, opaque objects stop the walk and semitransparent objects partially contribute to the result.
You might like to read up on ray tracing; there is a great body of literature on the subject and well-understood ways of solving what are basically the same problems you list exist.
The obvious question is do you really want the most accurate, and why?
I've worked on games that depended on line of sight and you really need to think clearly about what kind of line of sight you want.
First, can the AI see any part of your body? Or are you talking about "eye to eye" LOS?
Second, if the player's camera view is not his avatar's eye view, the player will not perceive your highly accurate LOS as highly accurate. At which point inaccuracies are fine.
I'm not trying to dissuade you, but remember that player experience is #1, and that might mean not having the best LOS.
A good friend of mine has done the AI for a long=-running series of popular console games. He often tells a story about how the AIs are most interesting (and fun) in the first game, because they stumble into you rather than see you from afar. Now, he has great LOS and spends his time trying to dumb them down to make them as fun as they were in the first game.
So why are you doing this? Does the game need it? Or do you just want the challenge?
There is no "one algorithm" for these since the inputs are not well defined.
If you treat Dust-In-Atmosphere as a constant value then there is an algorithm that can take it into account, but the fact is that dust levels will vary from point to point, and thus the algorithm you want needs to be aware of how your dust-data is structured.
The most used algorithm in todays ray-tracers is just incremental ray-marching, which is by definition not correct, but it does approximate the Ultimate Answer to a fair degree.
Even if you managed to incorporate all these properties into a single master-algorithm, you'd still have to somehow deal with how different people perceive the same setting. Some people are near-sighted, some far-sighted. Then there's the colour-blind. Not to mention that Dust-In-Atmosphere levels also affect tear-glands, which in turn affects visibility. And then there's the whole dichotomy between what people are actually seeying and what they think they are seeying...
There are far too many variables here to aim for a unified solution. Treat your environment as a voxelated space and shoot your rays through it. I suspect that's the only solution you'll be able to complete within a single lifetime...

What are good examples of genetic algorithms/genetic programming solutions? [closed]

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Genetic algorithms (GA) and genetic programming (GP) are interesting areas of research.
I'd like to know about specific problems you have solved using GA/GP and what libraries/frameworks you used if you didn't roll your own.
Questions:
What problems have you used GA/GP to solve?
What libraries/frameworks did you use?
I'm looking for first-hand experiences, so please do not answer unless you have that.
Not homework.
My first job as a professional programmer (1995) was writing a genetic-algorithm based automated trading system for S&P500 futures. The application was written in Visual Basic 3 [!] and I have no idea how I did anything back then, since VB3 didn't even have classes.
The application started with a population of randomly-generated fixed-length strings (the "gene" part), each of which corresponded to a specific shape in the minute-by-minute price data of the S&P500 futures, as well as a specific order (buy or sell) and stop-loss and stop-profit amounts. Each string (or "gene") had its profit performance evaluated by a run through 3 years of historical data; whenever the specified "shape" matched the historical data, I assumed the corresponding buy or sell order and evaluated the trade's result. I added the caveat that each gene started with a fixed amount of money and could thus potentially go broke and be removed from the gene pool entirely.
After each evaluation of a population, the survivors were cross-bred randomly (by just mixing bits from two parents), with the likelihood of a gene being selected as a parent being proportional to the profit it produced. I also added the possibility of point mutations to spice things up a bit. After a few hundred generations of this, I ended up with a population of genes that could turn $5000 into an average of about $10000 with no chance of death/brokeness (on the historical data, of course).
Unfortunately, I never got the chance to use this system live, since my boss lost close to $100,000 in less than 3 months trading the traditional way, and he lost his willingness to continue with the project. In retrospect, I think the system would have made huge profits - not because I was necessarily doing anything right, but because the population of genes that I produced happened to be biased towards buy orders (as opposed to sell orders) by about a 5:1 ratio. And as we know with our 20/20 hindsight, the market went up a bit after 1995.
I made a little critters that lived in this little world. They had a neural network brain which received some inputs from the world and the output was a vector for movement among other actions. Their brains were the "genes".
The program started with a random population of critters with random brains. The inputs and output neurons were static but what was in between was not.
The environment contained food and dangers. Food increased energy and when you have enough energy, you can mate. The dangers would reduce energy and if energy was 0, they died.
Eventually the creatures evolved to move around the world and find food and avoid the dangers.
I then decided to do a little experiment. I gave the creature brains an output neuron called "mouth" and an input neuron called "ear". Started over and was surprised to find that they evolved to maximize the space and each respective creature would stay in its respective part (food was placed randomly). They learned to cooperate with each other and not get in each others way. There were always the exceptions.
Then i tried something interesting. I dead creatures would become food. Try to guess what happened! Two types of creatures evolved, ones that attacked like in swarms, and ones that were high avoidance.
So what is the lesson here? Communication means cooperation. As soon as you introduce an element where hurting another means you gain something, then cooperation is destroyed.
I wonder how this reflects on the system of free markets and capitalism. I mean, if businesses can hurt their competition and get away with it, then its clear they will do everything in their power to hurt the competition.
Edit:
I wrote it in C++ using no frameworks. Wrote my own neural net and GA code. Eric, thank you for saying it is plausible. People usually don't believe in the powers of GA (although the limitations are obvious) until they played with it. GA is simple but not simplistic.
For the doubters, neural nets have been proven to be able to simulate any function if they have more than one layer. GA is a pretty simple way to navigate a solution space finding local and potentially global minimum. Combine GA with neural nets and you have a pretty good way to find functions that find approximate solutions for generic problems. Because we are using neural nets, then we are optimizing the function for some inputs, not some inputs to a function as others are using GA
Here is the demo code for the survival example: http://www.mempko.com/darcs/neural/demos/eaters/
Build instructions:
Install darcs, libboost, liballegro, gcc, cmake, make
darcs clone --lazy http://www.mempko.com/darcs/neural/
cd neural
cmake .
make
cd demos/eaters
./eaters
In January 2004, I was contacted by Philips New Display Technologies who were creating the electronics for the first ever commercial e-ink, the Sony Librie, who had only been released in Japan, years before Amazon Kindle and the others hit the market in US an Europe.
The Philips engineers had a major problem. A few months before the product was supposed to hit the market, they were still getting ghosting on the screen when changing pages. The problem was the 200 drivers that were creating the electrostatic field. Each of these drivers had a certain voltage that had to be set right between zero and 1000 mV or something like this. But if you changed one of them, it would change everything.
So optimizing each driver's voltage individually was out of the question. The number of possible combination of values was in billions,and it took about 1 minute for a special camera to evaluate a single combination. The engineers had tried many standard optimization techniques, but nothing would come close.
The head engineer contacted me because I had previously released a Genetic Programming library to the open-source community. He asked if GP/GA's would help and if I could get involved. I did, and for about a month we worked together, me writing and tuning the GA library, on synthetic data, and him integrating it into their system. Then, one weekend they let it run live with the real thing.
The following Monday I got these glowing emails from him and their hardware designer, about how nobody could believe the amazing results the GA found. This was it. Later that year the product hit the market.
I didn't get paid one cent for it, but I got 'bragging' rights. They said from the beginning they were already over budget, so I knew what the deal was before I started working on it. And it's a great story for applications of GAs. :)
I used a GA to optimize seating assignments at my wedding reception. 80 guests over 10 tables. Evaluation function was based on keeping people with their dates, putting people with something in common together, and keeping people with extreme opposite views at separate tables.
I ran it several times. Each time, I got nine good tables, and one with all the odd balls. In the end, my wife did the seating assignments.
My traveling salesman optimizer used a novel mapping of chromosome to itinerary, which made it trivial to breed and mutate the chromosomes without any risk of generating invalid tours.
Update: Because a couple people have asked how ...
Start with an array of guests (or cities) in some arbitrary but consistent ordering, e.g., alphabetized. Call this the reference solution. Think of a guest's index as his/her seat number.
Instead of trying to encode this ordering directly in the chromosome, we encode instructions for transforming the reference solution into a new solution. Specifically, we treat the chromosomes as lists of indexes in the array to swap. To get decode a chromosome, we start with the reference solution and apply all the swaps indicated by the chromosome. Swapping two entries in the array always results in a valid solution: every guest (or city) still appears exactly once.
Thus chromosomes can be randomly generated, mutated, and crossed with others and will always produce a valid solution.
I used genetic algorithms (as well as some related techniques) to determine the best settings for a risk management system that tried to keep gold farmers from using stolen credit cards to pay for MMOs. The system would take in several thousand transactions with "known" values (fraud or not) and figure out what the best combination of settings was to properly identify the fraudulent transactions without having too many false positives.
We had data on several dozen (boolean) characteristics of a transaction, each of which was given a value and totalled up. If the total was higher than a threshold, the transaction was fraud. The GA would create a large number of random sets of values, evaluate them against a corpus of known data, select the ones that scored the best (on both fraud detection and limiting the number of false positives), then cross breed the best few from each generation to produce a new generation of candidates. After a certain number of generations the best scoring set of values was deemed the winner.
Creating the corpus of known data to test against was the Achilles' heel of the system. If you waited for chargebacks, you were several months behind when trying to respond to the fraudsters, so someone would have to manually review large numbers of transactions to build up that corpus of data without having to wait too long.
This ended up identifying the vast majority of the fraud that came in, but couldn't quite get it below 1% on the most fraud-prone items (given that 90% of incoming transactions could be fraud, that was doing pretty well).
I did all this using perl. One run of the software on a fairly old linux box would take 1-2 hours to run (20 minutes to load data over a WAN link, the rest of the time spent crunching). The size of any given generation was limited by available RAM. I'd run it over and over with slight changes to the parameters, looking for an especially good result set.
All in all it avoided some of the gaffes that came with manually trying to tweak the relative values of dozens of fraud indicators, and consistently came up with better solutions than I could create by hand. AFAIK, it's still in use (about 3 years after I wrote it).
Football Tipping. I built a GA system to predict the week to week outcome of games in the AFL (Aussie Rules Football).
A few years ago I got bored of the standard work football pool, everybody was just going online and taking the picks from some pundit in the press. So, I figured it couldn't be too hard to beat a bunch of broadcast journalism majors, right? My first thought was to take the results from Massey Ratings and then reveal at the end of the season my strategy after winning fame and glory. However, for reasons I've never discovered Massey does not track AFL. The cynic in me believes it is because the outcome of each AFL game has basically become random chance, but my complaints of recent rule changes belong in a different forum.
The system basically considered offensive strength, defensive strength, home field advantage, week to week improvement (or lack thereof) and velocity of changes to each of these. This created a set of polynomial equations for each team over the season. The winner and score for each match for a given date could be computed. The goal was to find the set of coefficients that most closely matched the outcome of all past games and use that set to predict the upcoming weeks game.
In practice, the system would find solutions that accurately predicted over 90% of past game outcomes. It would then successfully pick about 60-80% of games for the upcoming week (that is the week not in the training set).
The result: just above middle of the pack. No major cash prize nor a system that I could use to beat Vegas. It was fun though.
I built everything from scratch, no framework used.
As well as some of the common problems, like the Travelling Salesman and a variation on Roger Alsing's Mona Lisa program, I've also written an evolutionary Sudoku solver (which required a bit more original thought on my part, rather than just re-implementing somebody else's idea). There are more reliable algorithms for solving Sudokus but the evolutionary approach works fairly well.
In the last few days I've been playing around with an evolutionary program to find "cold decks" for poker after seeing this article on Reddit. It's not quite satisfactory at the moment but I think I can improve it.
I have my own framework that I use for evolutionary algorithms.
I developed a home brew GA for a 3D laser surface profile system my company developed for the freight industry back in 1992.
The system relied upon 3 dimensional triangulation and used a custom laser line scanner, a 512x512 camera (with custom capture hw). The distance between the camera and laser was never going to be precise and the focal point of the cameras were not to be found in the 256,256 position that you expected it to be!
It was a nightmare to try and work out the calibration parameters using standard geometry and simulated annealing style equation solving.
The Genetic algorithm was whipped up in an evening and I created a calibration cube to test it on. I knew the cube dimensions to high accuracy and thus the idea was that my GA could evolve a set of custom triangulation parameters for each scanning unit that would overcome production variations.
The trick worked a treat. I was flabbergasted to say the least! Within around 10 generations my 'virtual' cube (generated from the raw scan and recreated from the calibration parameters) actually looked like a cube! After around 50 generations I had the calibration I needed.
Its often difficult to get an exact color combination when you are planning to paint your house. Often, you have some color in mind, but it is not one of the colors, the vendor shows you.
Yesterday, my Prof. who is a GA researcher mentioned about a true story in Germany (sorry, I have no further references, yes, I can find it out if any one requests to). This guy (let's call him the color guy) used to go from door-door to help people to find the exact color code (in RGB) that would be the closet to what the customer had in mind. Here is how he would do it:
The color guy used to carry with him a software program which used GA. He used to start with 4 different colors- each coded as a coded Chromosome (whose decoded value would be a RGB value). The consumer picks 1 of the 4 colors (Which is the closest to which he/she has in mind). The program would then assign the maximum fitness to that individual and move onto the next generation using mutation/crossover. The above steps would be repeated till the consumer had found the exact color and then color guy used to tell him the RGB combination!
By assigning maximum fitness to the color closes to what the consumer have in mind, the color guy's program is increasing the chances to converge to the color, the consumer has in mind exactly. I found it pretty fun!
Now that I have got a -1, if you are planning for more -1's, pls. elucidate the reason for doing so!
A couple of weeks ago, I suggested a solution on SO using genetic algorithms to solve a problem of graph layout. It is an example of a constrained optimization problem.
Also in the area of machine learning, I implemented a GA-based classification rules framework in c/c++ from scratch.
I've also used GA in a sample project for training artificial neural networks (ANN) as opposed to using the famous backpropagation algorithm.
In addition, and as part of my graduate research, I've used GA in training Hidden Markov Models as an additional approach to the EM-based Baum-Welch algorithm (in c/c++ again).
As part of my undergraduate CompSci degree, we were assigned the problem of finding optimal jvm flags for the Jikes research virtual machine. This was evaluated using the Dicappo benchmark suite which returns a time to the console. I wrote a distributed gentic alogirthm that switched these flags to improve the runtime of the benchmark suite, although it took days to run to compensate for hardware jitter affecting the results. The only problem was I didn't properly learn about the compiler theory (which was the intent of the assignment).
I could have seeded the initial population with the exisiting default flags, but what was interesting was that the algorithm found a very similar configuration to the O3 optimisation level (but was actually faster in many tests).
Edit: Also I wrote my own genetic algorithm framework in Python for the assignment, and just used the popen commands to run the various benchmarks, although if it wasn't an assessed assignment I would have looked at pyEvolve.
First off, "Genetic Programming" by Jonathan Koza (on amazon) is pretty much THE book on genetic and evolutionary algorithm/programming techniques, with many examples. I highly suggest checking it out.
As for my own use of a genetic algorithm, I used a (home grown) genetic algorithm to evolve a swarm algorithm for an object collection/destruction scenario (practical purpose could have been clearing a minefield). Here is a link to the paper. The most interesting part of what I did was the multi-staged fitness function, which was a necessity since the simple fitness functions did not provide enough information for the genetic algorithm to sufficiently differentiate between members of the population.
I am part of a team investigating the use of Evolutionary Computation (EC) to automatically fix bugs in existing programs. We have successfully repaired a number of real bugs in real world software projects (see this project's homepage).
We have two applications of this EC repair technique.
The first (code and reproduction information available through the project page) evolves the abstract syntax trees parsed from existing C programs and is implemented in Ocaml using our own custom EC engine.
The second (code and reproduction information available through the project page), my personal contribution to the project, evolves the x86 assembly or Java byte code compiled from programs written in a number of programming languages. This application is implemented in Clojure and also uses its own custom built EC engine.
One nice aspect of Evolutionary Computation is the simplicity of the technique makes it possible to write your own custom implementations without too much difficulty. For a good freely available introductory text on Genetic Programming see the Field Guide to Genetic Programming.
A coworker and I are working on a solution for loading freight onto trucks using the various criteria our company requires. I've been working on a Genetic Algorithm solution while he is using a Branch And Bound with aggressive pruning. We are still in the process of implementing this solution but so far, we have been getting good results.
Several years ago I used ga's to optimize asr (automatic speech recognition) grammars for better recognition rates. I started with fairly simple lists of choices (where the ga was testing combinations of possible terms for each slot) and worked my way up to more open and complex grammars. Fitness was determined by measuring separation between terms/sequences under a kind of phonetic distance function. I also experimented with making weakly equivalent variations on a grammar to find one that compiled to a more compact representation (in the end I went with a direct algorithm, and it drastically increased the size of the "language" that we could use in applications).
More recently I have used them as a default hypothesis against which to test the quality of solutions generated from various algorithms. This has largely involved categorization and different kinds of fitting problems (i.e. create a "rule" that explains a set of choices made by reviewers over a dataset(s)).
I made a complete GA framework named "GALAB", to solve many problems:
locating GSM ANTs (BTS) to decrease overlap & blank locations.
Resource constraint project scheduling.
Evolutionary picture creation. (Evopic)
Travelling salesman problem.
N-Queen & N-Color problems.
Knight's tour & Knapsack problems.
Magic square & Sudoku puzzles.
string compression, based on Superstring problem.
2D Packaging problem.
Tiny artificial life APP.
Rubik puzzle.
I once used a GA to optimize a hash function for memory addresses. The addresses were 4K or 8K page sizes, so they showed some predictability in the bit pattern of the address (least significant bits all zero; middle bits incrementing regularly, etc.) The original hash function was "chunky" - it tended to cluster hits on every third hash bucket. The improved algorithm had a nearly perfect distribution.
I built a simple GA for extracting useful patterns out of the frequency spectrum of music as it was being played. The output was used to drive graphical effects in a winamp plugin.
Input: a few FFT frames (imagine a 2D array of floats)
Output: single float value (weighted sum of inputs), thresholded to 0.0 or 1.0
Genes: input weights
Fitness function: combination of duty cycle, pulse width and BPM within sensible range.
I had a few GAs tuned to different parts of the spectrum as well as different BPM limits, so they didn't tend to converge towards the same pattern. The outputs from the top 4 from each population were sent to the rendering engine.
An interesting side effect was that the average fitness across the population was a good indicator for changes in the music, although it generally took 4-5 seconds to figure it out.
I don't know if homework counts...
During my studies we rolled our own program to solve the Traveling Salesman problem.
The idea was to make a comparison on several criteria (difficulty to map the problem, performance, etc) and we also used other techniques such as Simulated annealing.
It worked pretty well, but it took us a while to understand how to do the 'reproduction' phase correctly: modeling the problem at hand into something suitable for Genetic programming really struck me as the hardest part...
It was an interesting course since we also dabbled with neural networks and the like.
I'd like to know if anyone used this kind of programming in 'production' code.
I used a simple genetic algorithm to optimize the signal to noise ratio of a wave that was represented as a binary string. By flipping the the bits certain ways over several million generations I was able to produce a transform that resulted in a higher signal to noise ratio of that wave. The algorithm could have also been "Simulated Annealing" but was not used in this case. At their core, genetic algorithms are simple, and this was about as simple of a use case that I have seen, so I didn't use a framework for generation creation and selection - only a random seed and the Signal-to-Noise Ratio function at hand.
As part of my thesis I wrote a generic java framework for the multi-objective optimisation algorithm mPOEMS (Multiobjective prototype optimization with evolved improvement steps), which is a GA using evolutionary concepts. It is generic in a way that all problem-independent parts have been separated from the problem-dependent parts, and an interface is povided to use the framework with only adding the problem-dependent parts. Thus one who wants to use the algorithm does not have to begin from zero, and it facilitates work a lot.
You can find the code here.
The solutions which you can find with this algorithm have been compared in a scientific work with state-of-the-art algorithms SPEA-2 and NSGA, and it has been proven that
the algorithm performes comparable or even better, depending on the metrics you take to measure the performance, and especially depending on the optimization-problem you are looking on.
You can find it here.
Also as part of my thesis and proof of work I applied this framework to the project selection problem found in portfolio management. It is about selecting the projects which add the most value to the company, support most the strategy of the company or support any other arbitrary goal. E.g. selection of a certain number of projects from a specific category, or maximization of project synergies, ...
My thesis which applies this framework to the project selection problem:
http://www.ub.tuwien.ac.at/dipl/2008/AC05038968.pdf
After that I worked in a portfolio management department in one of the fortune 500, where they used a commercial software which also applied a GA to the project selection problem / portfolio optimization.
Further resources:
The documentation of the framework:
http://thomaskremmel.com/mpoems/mpoems_in_java_documentation.pdf
mPOEMS presentation paper:
http://portal.acm.org/citation.cfm?id=1792634.1792653
Actually with a bit of enthusiasm everybody could easily adapt the code of the generic framework to an arbitrary multi-objective optimisation problem.
At work I had the following problem: given M tasks and N DSPs, what was the best way to assign tasks to DSPs? "Best" was defined as "minimizing the load of the most loaded DSP". There were different types of tasks, and various task types had various performance ramifications depending on where they were assigned, so I encoded the set of job-to-DSP assignments as a "DNA string" and then used a genetic algorithm to "breed" the best assignment string I could.
It worked fairly well (much better than my previous method, which was to evaluate every possible combination... on non-trivial problem sizes, it would have taken years to complete!), the only problem was that there was no way to tell if the optimal solution had been reached or not. You could only decide if the current "best effort" was good enough, or let it run longer to see if it could do better.
There was an competition on codechef.com (great site by the way, monthly programming competitions) where one was supposed to solve an unsolveable sudoku (one should come as close as possible with as few wrong collumns/rows/etc as possible).What I would do, was to first generate a perfect sudoku and then override the fields, that have been given. From this pretty good basis on I used genetic programming to improve my solution.I couldn't think of a deterministic approach in this case, because the sudoku was 300x300 and search would've taken too long.
In a seminar in the school, we develop an application to generate music based in the musical mode. The program was build in Java and the output was a midi file with the song. We using distincts aproachs of GA to generate the music. I think this program can be useful to explore new compositions.
in undergrad, we used NERO (a combination of neural network and genetic algorithm) to teach in-game robots to make intelligent decisions. It was pretty cool.
I developed a multithreaded swing based simulation of robot navigation through a set of randomized grid terrain of food sources and mines and developed a genetic algorithm based strategy of exploring the optimization of robotic behavior and survival of fittest genes for a robotic chromosome. This was done using charting and mapping of each iteration cycle.
Since, then I have developed even more game behavior. An example application I built recently for myself was a genetic algorithm for solving the traveling sales man problem in route finding in UK taking into account start and goal states as well as one/multiple connection points, delays, cancellations, construction works, rush hour, public strikes, consideration between fastest vs cheapest routes. Then providing a balanced recommendation for the route to take on a given day.
Generally, my strategy is to use POJO based representaton of genes then I apply specific interface implementations for selection, mutation, crossover strategies, and the criteria point. My fitness function then basically becomes a quite complex based on the strategy and criteria I need to apply as a heuristic measure.
I have also looked into applying genetic algorithm into automated testing within code using systematic mutation cycles where the algorithm understands the logic and tries to ascertain a bug report with recommendations for code fixes. Basically, a way to optimize my code and provide recommendations for improvement as well as a way of automating the discovery of new programmatic code. I have also tried to apply genetic algorithms to music production amongst other applications.
Generally, I find evolutionary strategies like most metaheuristic/global optimization strategies, they are slow to learn at first but start to pick up as the solutions become closer and closer to goal state and as long as your fitness function and heuristics are well aligned to produce that convergence within your search space.
I once tried to make a computer player for the game of Go, exclusively based on genetic programming. Each program would be treated as an evaluation function for a sequence of moves. The programs produced weren't very good though, even on a rather diminuitive 3x4 board.
I used Perl, and coded everything myself. I would do things differently today.
After reading The Blind Watchmaker, I was interested in the pascal program Dawkins said he had developed to create models of organisms that could evolve over time. I was interested enough to write my own using Swarm. I didn't make all the fancy critter graphics he did, but my 'chromosomes' controlled traits which affected organisms ability to survive. They lived in a simple world and could slug it out against each other and their environment.
Organisms lived or died partly due to chance, but also based on how effectively they adapted to their local environments, how well they consumed nutrients & how successfully they reproduced. It was fun, but also more proof to my wife that I am a geek.
It was a while ago, but I rolled a GA to evolve what were in effect image processing kernels to remove cosmic ray traces from Hubble Space Telescope (HST) images. The standard approach is to take multiple exposures with the Hubble and keep only the stuff that is the same in all the images. Since HST time is so valuable, I'm an astronomy buff, and had recently attended the Congress on Evolutionary Computation, I thought about using a GA to clean up single exposures.
The individuals were in the form of trees that took a 3x3 pixel area as input, performed some calculations, and produced a decision about whether and how to modify the center pixel. Fitness was judged by comparing the output with an image cleaned up in the traditional way (i.e. stacking exposures).
It actually sort of worked, but not well enough to warrant foregoing the original approach. If I hadn't been time-constrained by my thesis, I might have expanded the genetic parts bin available to the algorithm. I'm pretty sure I could have improved it significantly.
Libraries used: If I recall correctly, IRAF and cfitsio for astronomical image data processing and I/O.
I experimented with GA in my youth. I wrote a simulator in Python that worked as follows.
The genes encoded the weights of a neural network.
The neural network's inputs were "antennae" that detected touches. Higher values meant very close and 0 meant not touching.
The outputs were to two "wheels". If both wheels went forward, the guy went forward. If the wheels were in opposite directions, the guy turned. The strength of the output determined the speed of the wheel turning.
A simple maze was generated. It was really simple--stupid even. There was the start at the bottom of the screen and a goal at the top, with four walls in between. Each wall had a space taken out randomly, so there was always a path.
I started random guys (I thought of them as bugs) at the start. As soon as one guy reached the goal, or a time limit was reached, the fitness was calculated. It was inversely proportional to the distance to the goal at that time.
I then paired them off and "bred" them to create the next generation. The probability of being chosen to be bred was proportional to its fitness. Sometimes this meant that one was bred with itself repeatedly if it had a very high relative fitness.
I thought they would develop a "left wall hugging" behavior, but they always seemed to follow something less optimal. In every experiment, the bugs converged to a spiral pattern. They would spiral outward until they touched a wall to the right. They'd follow that, then when they got to the gap, they'd spiral down (away from the gap) and around. They would make a 270 degree turn to the left, then usually enter the gap. This would get them through a majority of the walls, and often to the goal.
One feature I added was to put in a color vector into the genes to track relatedness between individuals. After a few generations, they'd all be the same color, which tell me I should have a better breeding strategy.
I tried to get them to develop a better strategy. I complicated the neural net--adding a memory and everything. It didn't help. I always saw the same strategy.
I tried various things like having separate gene pools that only recombined after 100 generations. But nothing would push them to a better strategy. Maybe it was impossible.
Another interesting thing is graphing the fitness over time. There were definite patterns, like the maximum fitness going down before it would go up. I have never seen an evolution book talk about that possibility.

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