http://marknelson.us Programming, mostly. Mon, 15 Apr 2013 12:11:06 +0000 en-US hourly 1 http://wordpress.org/?v=3.5.1 http://marknelson.us/2012/10/09/the-random-compression-challenge-turns-ten/ http://marknelson.us/2012/10/09/the-random-compression-challenge-turns-ten/#comments Tue, 09 Oct 2012 12:17:53 +0000 Mark Nelson http://marknelson.us/?p=1683 An update of the ten year old data compression challenge. Can your algorithm compress a million random digits?]]> http://marknelson.us/2012/10/09/the-random-compression-challenge-turns-ten/feed/ 167 http://marknelson.us/2012/02/01/im-in-the-money/ http://marknelson.us/2012/02/01/im-in-the-money/#comments Wed, 01 Feb 2012 16:36:28 +0000 Mark Nelson http://marknelson.us/?p=1437 It looks like all my long years of studying data compression might be ready to pay off: Hello Good Day, This is Troop Emonds With regards to your Company i am sending this email Regards to order some( Compression Machine )I will like to know the type and sizes you have in stock and get [...]]]> http://marknelson.us/2012/02/01/im-in-the-money/feed/ 6 http://marknelson.us/2012/01/21/a-visit-with-tim-bell/ http://marknelson.us/2012/01/21/a-visit-with-tim-bell/#comments Sun, 22 Jan 2012 02:22:50 +0000 Mark Nelson http://marknelson.us/?p=1407 I was in Christchurch, New Zealand, recently and had a chance to meet Tim for the first time in person. Tim teaches at the University of Canterbury in Christchurch, and is Deputy Head of the Computer Science and Software Engineering department. I got a chance to ask him about his work in data compression as well as one of his new areas of interest, Computer Science education.]]> http://marknelson.us/2012/01/21/a-visit-with-tim-bell/feed/ 0 http://marknelson.us/2011/12/24/streams-or-iterators/ http://marknelson.us/2011/12/24/streams-or-iterators/#comments Sat, 24 Dec 2011 18:21:11 +0000 Mark Nelson http://marknelson.us/?p=1393 When I updated my LZW reference code to use the latest C++ features, I abstracted my input and output functions using templates. Data was read and written using the iostreams paradigm, which requires simple classes that implement just a few functions. Would I have been better off using the iterator paradigm instead? The C++ algorithms [...]]]> http://marknelson.us/2011/12/24/streams-or-iterators/feed/ 3 http://marknelson.us/2011/11/08/lzw-revisited/ http://marknelson.us/2011/11/08/lzw-revisited/#comments Tue, 08 Nov 2011 15:21:41 +0000 Mark Nelson http://marknelson.us/?p=1056 In this updated look at LZW, I will first give a description of how LZW works, then describe the core C++ code that I use to implement the algorithm. I'll then walk you through the use of the algorithm with a few varieties of I/O. Finally, I'll show you some benchmarks and go over the history of this well-known compression algorithm.]]> http://marknelson.us/2011/11/08/lzw-revisited/feed/ 9 http://marknelson.us/2011/01/09/combinatorial-data-compression/ http://marknelson.us/2011/01/09/combinatorial-data-compression/#comments Sun, 09 Jan 2011 23:10:57 +0000 Mark Nelson http://marknelson.us/?p=154 Newcomers to the world of data compression often stumble on this old idea in hopes of creating a novel and powerful algorithm. In a nutshell, the idea is to create an enumerative coding system that uses combinatorial numbering to identify a message, in hopes of providing a more compact representation . Unfortunately, these schemes always [...]]]> http://marknelson.us/2011/01/09/combinatorial-data-compression/feed/ 4 http://marknelson.us/2010/08/01/the-pigeonhole-principle/ http://marknelson.us/2010/08/01/the-pigeonhole-principle/#comments Sun, 01 Aug 2010 19:01:01 +0000 Mark Nelson http://marknelson.us/2010/08/01/the-pigeonhole-principle/ The Pigeonhole Principle, also referred to as the Counting Theorem, is a handy tool for mathematicians, and naturally, computer programmers. The loose version of this principle says “After placing n pigeons into m compartments, if n is greater than m, you will find that some compartment must contain more than one pigeon.” Seems obvious, and [...]]]> http://marknelson.us/2010/08/01/the-pigeonhole-principle/feed/ 1 http://marknelson.us/2008/02/11/cashing-in-on-e-books/ http://marknelson.us/2008/02/11/cashing-in-on-e-books/#comments Mon, 11 Feb 2008 20:19:05 +0000 Mark Nelson http://marknelson.us/2008/02/11/cashing-in-on-e-books/ Jeff Bezos Hawks the Kindle It’s still not clear whether electronic books are the wave of the future or a consumer products cul-de-sac. Technology continues to improve, and there are certainly lots of good reasons for a device like Amazon’s Kindle to be the leading edge of a major wave of adoption. A few of [...]]]> http://marknelson.us/2008/02/11/cashing-in-on-e-books/feed/ 1 http://marknelson.us/2007/07/13/lempel-award/ http://marknelson.us/2007/07/13/lempel-award/#comments Fri, 13 Jul 2007 13:09:51 +0000 Mark Nelson /2007/07/13/lempel-award/ The IEEE has announced its list of medal winners for 2007, and this year’s Richard Hamming medal was awarded to Dr. Abraham Lempel: For pioneering work in data compression especially the Lempel-Ziv algorithm. This is a timely award, because it comes on the 30th anniversary of the publication of the first of two seminal papers [...]]]> http://marknelson.us/2007/07/13/lempel-award/feed/ 0 http://marknelson.us/2006/11/02/forgents-jpeg-litigation-run-is-over/ http://marknelson.us/2006/11/02/forgents-jpeg-litigation-run-is-over/#comments Thu, 02 Nov 2006 15:57:23 +0000 Mark Nelson /2006/11/02/forgents-jpeg-litigation-run-is-over/ It looks like Forgent’s long run of JPEG lawsuit revenue has now officially dried up. The Austin American Statesman has an article (registration required) that says the remaining JPEG lawsuits have all been settled, with a grand total of less than $8 million from somewhere fewer than 20 defendents. Apparently, the whole JPEG lawsuit run [...]]]> http://marknelson.us/2006/11/02/forgents-jpeg-litigation-run-is-over/feed/ 0