Algorithmics
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Bizarre Soft Robots Evolve to Run
This crazy looking thing is a simulated robot, made up of two different kinds of muscles along with bones and soft tissue for structure. This robot wasn't designed, it was evolved over a thousand virtual generations to move as fast, as far, and as functionally as possible. It's nice that these researchers (including Jeff Clune from the University of Wyoming, who posted this video) are totally aware that these robots are wacky little things, but it's kind of amazing how successful evolution is at creating success out of just a few basic structures. And in the greater scheme of things, 1,000 generations is not a whole lot: in human terms, that's only 25,000 years, while modern Homo Sapiens have been around for ten times as long.
i 62 Votes [EDIT] Added FAQ here: http://rogeralsing.com/2008/12/09/genetic-programming-mona-lisa-faq/ Added Gallery here: http://rogeralsing.com/2008/12/11/genetic-gallery/ This weekend I decided to play around a bit with genetic programming and put evolution to the test, the test of fine art :-) I created a small program that keeps a string of DNA for polygon rendering. The procedure of the program is quite simple:
Genetic Programming: Evolution of Mona Lisa | Roger Alsing Weblog
multi-threaded synchronisation patterns
Operational transformation (OT) is a technology for supporting a range of collaboration functionalities in advanced collaborative software systems. OT was originally invented for consistency maintenance and concurrency control in collaborative editing of plain text documents. Two decades of research has extended its capabilities and expanded its applications to include group undo, locking, conflict resolution, operation notification and compression, group-awareness, HTML/XML and tree-structured document editing, collaborative office productivity tools, application-sharing, and collaborative computer-aided media design tools (see OTFAQ ). In 2009 OT has been adopted as a core technique behind the collaboration features in Google Wave and Google Docs , which are taking OT to a new range of web-based applications. [ edit ] History Operational Transformation was pioneered by C.
Operational transformation
Imagine you’re a programmer who is developing a new web browser. There are many malicious sites on the web, and you want your browser to warn users when they attempt to access dangerous sites. For example, suppose the user attempts to access http://domain/etc .
Why Bloom filters work the way they do | DDI
A Bloom filter , conceived by Burton Howard Bloom in 1970, [ 1 ] is a space-efficient probabilistic data structure that is used to test whether an element is a member of a set . False positive retrieval results are possible, but false negatives are not; i.e. a query returns either "inside set (may be wrong)" or "definitely not in set". Elements can be added to the set, but not removed (though this can be addressed with a counting filter). The more elements that are added to the set, the larger the probability of false positives.
Bloom filter
The bitap algorithm (also known as the shift-or , shift-and or Baeza–Yates–Gonnet algorithm) is an approximate string matching algorithm. The algorithm tells whether a given text contains a substring which is "approximately equal" to a given pattern, where approximate equality is defined in terms of Levenshtein distance — if the substring and pattern are within a given distance k of each other, then the algorithm considers them equal. The algorithm begins by precomputing a set of bitmasks containing one bit for each element of the pattern. Then it is able to do most of the work with bitwise operations , which are extremely fast.
Bitap algorithm
Hash Functions
Hash functions are functions that map a bit vector to another bit vector, usually shorter than the original vector and usually of fixed length for a particular function. There are three primary uses for hash functions: Fast table lookup Message digests Encryption Fast Table Lookup Fast table lookup can be implemented using a hash function and a hash table.