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TectoMT Tutorial

Welcome at TectoMT Tutorial. This tutorial should take about 2 hours.

What is TectoMT

TectoMT is a highly modular NLP (Natural Language Processing) software system implemented in Perl programming language under Linux. It is primarily aimed at Machine Translation, making use of the ideas and technology created during the Prague Dependency Treebank project. At the same time, it is also hoped to significantly facilitate and accelerate development of software solutions of many other NLP tasks, especially due to re-usability of the numerous integrated processing modules (called blocks), which are equipped with uniform object-oriented interfaces.

Prerequisities

Installation and setup

In this tutorial, we assume that TectoMT has been successfully installed on your machine. For installation details, see Getting started in TectoMT Developer's Guide.

Before running any experiments with TectoMT, you must set up your environment by running

source devel/config/init_devel_environ.sh

Theoretical background

TrEd

TectoMT Architecture

Blocks, scenarios and applications

In TectoMT, there is the following hierarchy of processing units (software components that process data):

This tutorial itself has its blocks in devel/libs/blocks/Tutorial and the application in devel/applications/tutorial.

Layers of Linguistic Structures

TectoMT blocks repository is saved in devel/libs/blocks/. In correspondence with …, the blocks are located in directories describing their purpose.

Thus, the set of TectoMT layers is Cartesian product {S,T} x {English,Czech} x {W,M,P,A,T}, in which:

Example: Block adding Czech morphological tags (pos, case, gender, etc.) can be found in devel/libs/blocks/SCzechW_toSCzechM/Simple_tagger.pm.

There are also other directories for other purpose blocks, for example blocks which only print out some information go to devel/libs/Print.

First application

Once you have TectoMT installed on your machine, you can find this tutorial in devel/applications/tutorial/. After you cd in to this directory, you can see our plain text sample data in sample.txt.

Most applications are defined in Makefiles, which describe sequence of blocks to be applied on our data. In our particular Makefile, four blocks are going to be applied on our sample text: sentence segmentation, tokenization, tagging and lemmatization. Since we have our input text in plain text format, the file is going to be converted into tmt format beforehand (the in section).

We can run the application:

make all

Our plain text data sample.txt have been transformed into tmt, internal TectoMT format, and saved into sample.tmt. Then, all four blocks have been loaded and our data has been processed. We can now examine sample.tmt using a regular text editor. We'll now stop and describe data structure in TectoMT.

Changing the scenario

We'll now add syntax analysis to our scenario by adding four more blocks. Instead of

analyze:
        brunblocks -S -o \
                SEnglishW_to_SEnglishM::Sentence_segmentation_simple \
                SEnglishW_to_SEnglishM::Penn_style_tokenization \
                SEnglishW_to_SEnglishM::TagTnT \
                SEnglishW_to_SEnglishM::Lemmatize_mtree -- sample.tmt

we'll have:

analyze:
        brunblocks -S -o \
                SEnglishW_to_SEnglishM::Sentence_segmentation_simple \
                SEnglishW_to_SEnglishM::Penn_style_tokenization \
                SEnglishW_to_SEnglishM::TagTnT \
                SEnglishW_to_SEnglishM::Lemmatize_mtree  \
                SEnglishM_to_SEnglishA::McD_parser_local \
                SEnglishM_to_SEnglishA::Fix_McD_Tree \
                SEnglishM_to_SEnglishA::Fill_afun_after_McD -- sample.tmt

Note: Makefiles use tabulators to mark command lines. Make sure your lines start with tabulator (or two tabulators) and not, for example, with 4 spaces.

After running

make all

we can examine our sample.tmt again. Really, an analytical layer SEnglishA describing a dependency tree with analytical functions (<afun>) has been added to each bundle.

Adding a new block

The linguistic structures in TectoMT are represented using the following object-oriented interface/types:

We'll now examine an example of a new block in file devel/applications/tutorial/Tutorial.pm

This block illustrates the most common methods for accessing objects:

Attributes of documents, bundles or nodes can be accessed by attribute getters and setters, for example:

Our tutorial block Tutorial.pm is ready to use:

    cp libs/blocks/Tutorial/Tutorial.pm devel/libs/blocks/Print/Tutorial.pm
 
    print_afun:
            brunblocks -S -o Print::Tutorial -- sample.tmt
 

We can observe our new block behaviour:

make print_afun

Writing an advanced block

In this application, we'll split the text into finite clauses.

Motivation:

Task: A block which, given an analytical tree (SEnglishA), fills each a-node with nummerical attribute <clause> so that nodes in the same finite clause are marked with the same number of clause.

Algorithm:

Instructions: There is a block template with hints in devel/libs/blocks/Tutorial/Tutorial_fill_finite_clauses.pm. Copy the file to SEnglishA_to_SEnglishT and edit this file using the hints in it. Also, don't forget to change the name of package (to SEnglishA_to_SEnglishT::Tutorial_fill_finite_clauses). The ouput of this block should be the same a-tree only with nummerical value <clause> attached to each a-node. There is also a printing block devel/libs/blocks/Tutorial_print_finite_clauses.pm which will print out the a-nodes grouped by clauses:

finite_clauses:
        brunblocks -S -o \
                SEnglishA_to_SEnglishT::Tutorial_fill_finite_clauses \
                Print::Tutorial_print_finite_clauses -- sample.tmt

Final task: ?

Further information


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