Lex and Yacc

Lex and Yacc are two software tools used in developing compilers and interpreters (like the Windows command interpreter (cmd.exe) and Bourne again shell (bash) in Unix systems. The book of Levine, Mason, and Brown is a perfect book to learn lex and yacc.

There are also a couple of websites describing how to use lex and yacc. I find http://dinosaur.compilertools.net/ a great place to start.

Database systems

A couple of database systems that people can use freely (including the source code):

PostgreSQL - an advanced object-relational database system.
MySQL - relational database system.
SQLite - a C library system that implements an SQL database engine.

My personal favorite is PostgreSQL. I have been using it for 4 years now. MySQL is quite good too. SQLite on the other hand is great for small projects that require some database capability.

Fairy tales

I found a website about Hans Christian Andersen's 168 tales. Most of the stories are provided in the website along with the original artworks. Google lists a couple of other websites showcasing Hans Christian Andersen's stories. Some interesting tidbits about Andersen are available in wikipedia.

My inspiration

Gotta finish that research!

Easter Sunday

Happy easter everyone!

My Final Four

Chicago : Illinois fighting illini
Albuquerque : Louisville cardinals
Syracuse : UNC tar heels
Austin : Kentucky wildcats

Almost eliminated

The blue devils and the wolfpack were defeated by the spartans and the badgers respectively. The tar heels however survived the showndown with the wildcats -- by 1 point! The Final Four contenders from the ACC were almost eliminated in one night.

Duke blue devils (68) - Michigan St. spartans (78) [box score]
NC St. wolfpack (56) - Wisconsin badgers (65) [box score]
UNC tar heels (67) - Villanova wildcats (66) [box score]

T-rex tissue

CNN.com reports about a 70-million-year-old soft tissue recovered from a Tyrannosaurus rex. It seems that the scientists are interested to know if DNA can be extracted from this jurassic tissue.

Hiding alarm clock

MIT Media lab developed clocky, an alarm clock that would roll and hide whenever you hit the snooze button. Crazy. hehehe.

Graphviz

Graphviz is a tool to draw large directed and undirected graphs. The graphviz version for Mac OS X is particularly cool (btw, there are versions for Windows and Linux too). I may use this tool in my research work soon.

Star Wars cartoons

In case you miss the new episodes of animated Star Wars, you can still watch them online at the CN website.

Partition congruences

The number 4 can be partitioned in 5 ways. 1+1+1+1+1, 2+1+1, 2+2, 3+1, and 4. The number 9 can be partitioned in 30 ways and 14 in 135 ways. In fact, any number ending in 4 or 9 can be partitioned in x ways, where x is divisible by 5. The numbers 4, 9, and 14 are said to be congruent to each other.

This mathematical pattern has been observed by the genius Srinivasa Ramanujan decades ago. He found partition congruences for 5, 7 and 11. Recently, Karl Mahlburg, a PhD student at the University of Wisconsin in Madison, USA, generalized this theory on partition congruences. The new scientist magazine reports that his results have applications in particle physics and computer security.

Hashing

Lately I had to implement a hash function to speed up my program. This website about minimal perfect hashing is helpful.

Demons out! ... and Jackets too

The West Virginia mountaineers routed the Wake Forest demon deacons last night. The mountaineers came too strong after the half-time. The deacons managed to tie the score at the end of the second half and in the first OT -- but came short in the second OT. Story is here.

UPDATE: The Georgia Tech yellow jackets lost to Louisville cardinals this afternoon. Story is here.

FINAL SCORES:
West Virginia mountaineers (111) - Wake Forest demon deacons (105) [box score]
Louisville cardinals (76) - Georgia Tech yellow jackets (54) [box score]

Duke blue devils, NC State wolfpack, and UNC tar heels are still dancing.

So Long Dixon

Carlos Dixon and his team lost the second round of NIT to Memphis tigers. They gave us a thrilling inagural season in the ACC and we are very proud of them. The full story is here.

FINAL SCORE:
Memphis tigers (83) - Virginia Tech hokies (62) [box score]

Open source math software

Here I am again. Looking for open source alternatives to expensive software. This time, alternatives to Mathematica, MatLab, and S/S+.

If you don't have the bucks, a decent alternative to Mathematica is Maxima. Maxima had its origins to DOE Macsyma which was the first among the modern computer algebra systems like Maple and Mathematica. Maxima does symbolic integration, 3D plotting, and ODE solving among many other features. It is available for Windows and Linux systems.

SciLab on the other hand is a very good alternative to MatLab. Scilab is a scientific software package for numerical computations. It provides a powerful open computing environment for engineering and scientific applications. SciLab is available for Windows, Linux, HP-UX, and Solaris platforms.

Looking for an open source statistical software? I recommend R, a very sophisticated open source statistical package. R uses a dialect of the S/S+ statistical software package. R is available for Windows, Linux, and MacOS systems.

Of course Mathematica and MatLab are great software packages. However, they are just too expensive for me.

Sequencing the X chromosome

Nature published a paper about the recently sequenced X chromosome. The paper is available online here.

I wish all research papers are freely available online to the public. These papers are anyway funded by money which ultimately came from the reading public (through taxes). :)

Going to the second round

The hokies have finally beaten the owls after a total of 10 match-ups. Dixon and his team routed the owls, 60-50, last night at the Cassell.

LOTR parody

I found this LOTR parody by Jonas Diego, a pinoy comics artist working in Makati. The humor is pinoy and the drawings are great. It seems that the caricatures of his friends (also pinoy comics artists) composed the cast of characters in the parody.

Comic links: Teaser, Issue 1, Issue 2.

Day after spring break

Oh yeah ... reported to office early ... summarized work done during the break and on with a meeting with my adviser.

The meeting went well and of course I have more things to work on. I plan to have my research "defense" early april so I really have to make that prototype working!