This is a test

Παπαδόπουλος Βαγγέλης Μήτσος Θανάσης Λάλας Μαρινάκης Καρούζος Ψωμάς

How-To: Eclipse Ganymede 3.4.1 with SVN and GWT support

After long-way troubled support of Subversion in Eclipse Ganymede (still no built-in support…), this how-to attempts to install the Subversive plug-in on SR1 (3.4.1) release. Support for GWT is also added with the Cypal Studio for GWT. Tested on Ubuntu 8.04.1 with the versions referred.

• Download Ganymede 3.4.1 for Java EE from here. The file for Linux x86 is eclipse-jee-ganymede-SR1-linux-gtk.tar.gz.
• Extract Eclipse and use clean workspace and .eclipse folders.
• Use the steps written in this guide to install Subversive 0.7.5 with SVNKit 2.0.5 connectors for both SVN 1.4/1.5.
• Download Cypal Studio for GWT 1.0 plugin from here. The file name is cypal.studio.for.gwt-1.0.zip.
• Read this thread on how to install Cypal Studio.
• Read the docs on how to configure Cypal Studio.

The Earth at your hands!

Watch out the following amazing video that presents the use of WorldWind Java SDK for a multi-touch wall screen. The result is astonishing!

I can already imagine wannabe-wolrd conquers using this technology to find the place where to settle their throne…
Here is a presentation of this exciting technology covered in JavaOne session.

Reference:
http://earthissquare.com/2008/05/09/multi-touch-wall-wwjava-amazing/

Ubuntu 8.04, aka Hardy Heron

After some time, I am back with a “simple user” review of Hardy Heron:

http://arstechnica.com/reviews/os/hardy-heron-review.ars

The article recounts all the features of an Ubuntu installation, plus some new ones. Noteworthy is Wubi, an installation of Ubuntu in Windows, that is manageble from Add/Remove Programs. That, in my opinion, hits the spot for users that are reluctant to Boot-Partition-Install-Dual boot with no way back. I know my way around boot managers, but even I don’t mess around with my windows installation (too many sleepless nights installing windows after a failed OS installation, and right before a deadline).

HTC QuickGPS problem

On my HTC Touch Cruise, QuickGPS stopped updating the GPS ephemeris.

SH4Y’s QuickGPS Fix.CAB solved the problem.

Amazon’s Mechanical Turk

…or in other words, how to rent an army of slaves on demand.

Quoting from Amazon Web Services (emphasis mine):

Amazon Mechanical Turk is a marketplace for work that requires human intelligence. The Mechanical Turk web service enables companies to programmatically access this marketplace and a diverse, on-demand workforce. Developers can leverage this service to build human intelligence directly into their applications.
While computing technology continues to improve, there are still many things that human beings can do much more effectively than computers, such as identifying objects in a photo or video, performing data de-duplication, transcribing audio recordings or researching data details. Traditionally, tasks like this have been accomplished by hiring a large temporary workforce (which is time consuming, expensive and difficult to scale) or have gone undone.
Mechanical Turk aims to make accessing human intelligence simple, scalable, and cost-effective. Businesses or developers needing tasks done (called Human Intelligence Tasks or “HITs”) can use the robust Mechanical Turk APIs to access thousands of high quality, low cost, global, on-demand workers — and then programmatically integrate the results of that work directly into their business processes and systems. Mechanical Turk enables developers and businesses to achieve their goals more quickly and at a lower cost than was previously possible.

I can imagine requests being transparently serviced by an army of slaves somewhere in this world.
It always happened but now this army of slaves can be rented transparently, through a well defined API!

• On-Demand/Elastic Workforce
• Quality Management Tools
• Lower Cost Structure

A very interesting idea, that somehow does not put a smile in my face for some reason…

Lego Mindstorm NXT self balancing robot

Lego Mindstorm NXT are a great platform for many things such as games, education etc.

In the following I will described my adventures with the standard LEGO Mindstorm NXT package + a Gyro from hitechnic and MATLAB 2007b.
The quick guide is to download the wonderful package NXTway_GS and follow the instructions there. In what follows I am trying to explain the basic technologies used in NXTway_GS.

The long term goal of the project is to examine the possibilities of using LEGO Mindstorms as a way to teach Linear/Fuzzy Control. The short term goal is… to have fun.

So I need two or three “classical” case studies. The first thing that came in my mind is the inverted pendulum problem, or in this case the more interesting self-balancing robot problem. But first things first.

Trac, SVN quick howto on a linux Debian

In the following, I will present a mini guide to setup Trac 0.10.3 and SVN services on a Linux Debian stable.

I needed a per project authentication both in trac and in svn.

I just finished it, seems to be working, will check it out in a few days, hope it does not burn your PC and that I did not forget anything crucial.
Careful when copy pasting code, the double quotes get messed up.

Text Analysis inside Lucene

Lucene (http://lucene.apache.org) is a well-known Informational Retrieval (IR) library, implemented in Java, which allows you to add powerful indexing and searching capabilities to your application.

Briefly, there are 2 steps in using Lucene. First, you “feed” it with text which may come from plain text files or other compound documents, such as .pdf or .doc, after extracting their textual information. This process is called indexing, which creates a suitable data structure that allows for fast random access to words stored inside it. The concept behind it is analogous to an index at the end of a book, which quickly locate pages that discuss certain topics. The second step is to actually use the previously created index, that is search for words to find documents where they appear. Lucene supports a wide range of queries such as single and multiterm queries, phrase, queries, wildcards, result ranking and sorting.

Analysis, in Lucene, is the process of converting field text into its most fundamental indexed representation, terms. These terms are used to determine what documents match a query during searches. For example, if this sentence were indexed, the terms might start with for and example, and so on, as separate terms in sequence. An analyzer is an encapsulation of the analysis process. An analyzer tokenizes text by performing any number of operations on it, which could include extracting words, discarding punctuation, removing accents from characters, lowercasing (also called normalizing), removing common words, reducing words to a root form (stemming), or changing words into the basic form (lemmatization). This process is also called tokenization, and the chunks of text pulled from a stream of text are called tokens. Tokens, combined with their associated field name, are terms.

Scientific Workplace και Ελληνικά

Το Scientific workplace είναι ένα πολύ καλό εμπορικό front-end για το Latex.

Θα περιγράψουμε ένα τρόπο να γράψουμε ελληνικά με το Scientific Workplace που βασίζεται στο omega του Γιάννη Χαραλάμπους.

• Αποσυμπιέζουμε το rar αρχείο στο C:\ με την προυπόθεση ότι η εγκατάσταση του SWP είναι στο C:\SWP55\ Το rar αυτό αρχείο περιέχει ορισμούς για ελληνικά fonts.
• Αλλάζουμε τα Regional settings του Η/Υ για τα non-unicode προγράμματα σε English από το Control Panel
• Μέσα στο SWP κάνουμε την εξής ρύθμιση:

  Typeset->Expert Settings -> DVI Format Settings -> TeX Live Lambda

• Ανοίγουμε το tex αρχείο και δοκιμάζουμε να γράψουμε κάτι στα ελληνικά. Αφού το κάνουμε Typeset->DVI preview πρέπει να φαίνονται κανονικά όλοι οι ελληνικοί χαρακτήρες.