Manolis Perakakis world

News, diary, journal, whatever

Prime time for Distributed Speech Recognition? February 23, 2009

While an undergraduate student a few years ago I worked on Distributed Speech Recognition (DSR). The main purpose of DSR is to compress the acoustic features used by a speech recognizer, over a data (instead of voice) network, thus saving bandwidth (cost effective) and allowing the use of full speech recognition in mobile terminals. As it compresses acoustic features for speech recognition (not speech signal transmission/reproduction) purposes it can achieve very low bit rates. You can think of it as analogous of what mp3 is for music transmission and storage.

Depicted next is a simple overview of a DSR architecture (model 2). Note that the mobile terminals depicted are Symbian’s reference devices corresponding to smartphone, handheld and PDA respectively (Ooops too old images – it should be back in 2001; should upgrade to something like iPhone or Android …)

My work with Prof. V.Digalakis concluded that one can successfully take advantage of DSR with only a 2 kbps coding, which is an extremely low data rate. After that i ported the DSR engine to a Zaurus Linux PDA and made it work in real-time (a 16MB, 200 MHz StrongArm processor).

Although my recent work focus is now on Multi-modal (speech) interfaces I still keep an eye on DSR. It seems that with the emergence of powerful mobile terminals and the announcement of speech recognition support for Android and iPhone by Google, DSR might become soon a hot topic!

P.S. I just found out my DSR page is ranked 3rd by Google after W3C and ETSI. Holy moly!

Coolness factor: ?


Ten reasons why we love Linux March 24, 2008

Filed under: Linux — perak @ 4:00 pm

I first used Linux in ’95 for the operating systems course. A couple of years later I permantely switched to Linux, getting rid of the Windows crap for two main reasons:

First, Windows was too damn unstable, to the point of being useless. I was too tired of the “blue screens of death” and maintenance was a hell.  Microsoft was even advertising “innovations” such as sym links and a file system with more than 16 character long names… (no comment here!)

Second, Linux was such a better development platform & a  pretty learning tool for wannabe geeks, you could not resist playing with!

I was trying to persuade people and friends to give Linux a try for a long time. This came up to be difficult even inside an academic institution, so I gradually gave-up.

Although much has changed since then (Windows finally became somewhat stable,  Linux got easier installation methods/better hardware support and wider adoption), the debate is not over yet!

Dan Martin in his post “Things I can do in Linux that I can’t do on Windows” gives 11 reasons why he likes Linux. Although i disagree with item 6 (thus 10 used in the post title), overall it is a nice article that can help some people to finally change their mind 🙂


gentoo layman utility February 23, 2008

Filed under: Linux — perak @ 12:28 am

One reason to stick with Gentoo Linux is the superior portage package mangement based on BSD ports and the thousands of packages (i believe more than 15000! nowdays) to choose from.

Nevertheless, some packages may exist that have not yet make it to the official portage tree. Although one could use the corresponding ebuild, outside the portage tree, in a local overlay, nowdays there is the possibilty to add a bunch of such overlays by using the layman utility, e.g. “layman -a voip” will add the voip overlay, containing voip related  ebuilds to a local portage tree.

I found out about layman while searching for a SMplayer ebuild which is located in the berkano overlay along with other interesting software.  Other “extra” packages found in overlays include the azureus-gcj build,  second-life, NX server and many more.


Nokia buys Trolltech, gets on the mobile Linux bandwagon! January 28, 2008

Filed under: embedded,Linux,mobile,technology — perak @ 8:39 pm

I just came across this linuxdevice article, according to which Nokia will buy Trolltech! Interesting news! It seems Nokia is willing to adopt Linux in mobiles, in addition to the already Linux based web-pads (N800, N810) which use the Maemo environment (based on Gtk+/gnome). Expect a Gtk+/Qt war in the mobile platform arena too!

Nokia had already made a move towards Linux by embracing the “Open C” libraries last spring in order to help accelerate application development and porting to the Symbian OS.

After the recent Linux push by Google Android, it seems everybody is rushing to get on the mobile Linux bandwagon! Until now, only Motorola tried to embrance Linux, with limited success in far east Asia (China mainly).  The Nokia move will hopefully have a great effect on Linux penetration. With this move Nokia will finally lead two different mobile OSes (Symbian and Linux) which is a very cool move against the rest players (see Microsoft!)


gentoo update January 19, 2008

Filed under: Linux — perak @ 1:02 am


I am definitely “behind the technology curve” as a friend of mine calls it. My gentoo Linux system is of 2006.1 and i haven’t updated my portage tree, since April 2007! I wonder whether the gentoo guys still exist and are still top of the line. I noticed gentoo-based distributiions like Sabayon that look promising. And as shown in, gentoo is still relative popular (about 17th, used to be < 10 most of the time), despite recent problems (no 2007.1 release, various other problems). I hope they keep the good work this year too …

LWN ( has this nice yearly Linux review. KDE-4 is out,  this  is great, but  i am  thinking of  turning to xfce  for  this year (keep it simple dude!)