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T-LAB
Introduction
What T-LAB does and what it enables us to do
Requirements and Performances
Corpus Preparation
Corpus Preparation
Structural Criteria
Formal Criteria
File
Import a single file...
Prepare a Corpus (Corpus Builder)
Open an existing project
Settings
Automatic and Customized Settings
Dictionary Building
Co-occurrence Analysis
Word Associations
Co-Word Analysis and Concept Mapping
Comparison between Word pairs
Sequence and Network Analysis
Concordances
Thematic Analysis
Thematic Analysis of Elementary Contexts
Modeling of Emerging Themes
Thematic Document Classification
Dictionary-Based Classification
Key Contexts of Thematic Words
Comparative Analysis
Specificity Analysis
Correspondence Analysis
Multiple Correspondence Analysis
Cluster Analysis
Singular Value Decomposition
Lexical Tools
Text Screening / Disambiguations
Corpus Vocabulary
Stop-Word List
Multi-Word List
Word Segmentation
Other Tools
Variable Manager
Advanced Corpus Search
Contingency Tables
Editor
Glossary
Analysis Unit
Association Indexes
Chi-Square
Cluster Analysis
Coding
Context Unit
Corpus and Subsets
Correspondence Analysis
Data Table
Disambiguation
Dictionary
Elementary Context
Frequency Threshold
Graph Maker
Homograph
IDnumber
Isotopy
Key-Word (Key-Term)
Lemmatization
Lexical Unit
Lexie and Lexicalization
Markov Chain
MDS
Multiwords
N-grams
Naïve Bayes
Normalization
Occurrences and Co-occurrences
Poles of Factors
Primary Document
Profile
Specificity
Stop Word List
Test Value
Thematic Nucleus
TF-IDF
Variables and Categories
Words and Lemmas
Bibliography
www.tlab.it

Automatic and Customized Settings


The choice of automatic (A) or customized (B) settings relates to the list of Keywords Key-words used in all analyses performed with T-LAB. This choice is reversible until the user performs operations that modify the dictionary of the corpus.

A) AUTOMATIC SETTINGS

When choosing automatic settings the list of keywords includes up to a maximum of 5,000 lexical units automatically selected by T-LAB, which belong to the category of content words: nouns, verbs, adjectives and adverbs.

The selection criterion varies according to the kind of file analysed.

If the corpus is a single text T-LAB simply selects the lexical units with the highest occurrence values.

If the corpus is made up of two or more texts T-LAB uses the following algorithm:

· it selects the words with occurrence values higher than the minimum threshold;
· it computes the TF-IDF or applies the chi-square test to all the crosses of each selected word for all the texts being analysed (N.B.: In the case of chi square test, the maximum number of text allowed is 500);
· it selects the words with the TF-IDF or chi-square highest values, that is those words that, in the corpus, make the difference.

N.B.:
- In the case that the corpus consists of two or more texts, the user can choose the selection criterion (CHI square or TF-IDF) in the import stage (see below);

- when the automatic settings option is enabled, the table with the list of Keywords includes a 'T-LAB' column which indicates the importance of each item according to the selected criterion (see below).

A) CUSTOMIZED SETTINGS

When choosing customized settings the user is allowed to select, rename and group the lexical units (i.e. words, lemmas or categories) to be included in subsequent T-LAB analyses.

All the lexical units with an occurrence value which is equal or superior to the preset threshold are listed (list 1).
Some of these, that is those indicated with "v", belong to a sub-list (list 2) create by
T-LAB (see automatic settings).

Depending on the analyses to be performed, the user can decide whether to use/modify the more extended list (1) or the sub-list (2) of the T-LAB key terms.

In both cases the operations available are the following:

  • change the threshold value;
  • select which lemmas are to be excluded from analysis;
  • restore one or more lemmas for use;
  • select/deselectitems.

By clicking either the list "(1)" or the list "(2)" button the customized option of Analysis Settings is enabled (see below).

All options regarding interventions on individual entries are accessed by right clicking the mouse on any item of the table (see below).

 

In order to change the label (i.e. rename) of a single lemma, proceed as follows:

1. be sure that the "RENAME" option is selected;
2. click on an item of the list;
3. select one word or type a new label in the appropriate box:
4. click on "RENAME".


In order to group two or more lemmas, proceed as follows:


1. be sure that the "GROUP" option is selected;
2. click on two or more items of the list;
3. select one lemma or type a new label in the appropriate box;
4. click on "REPLACE".


Additional options can be enabled using the right click in the box with the items to be renamed / grouped (A) or in the box with the discarded lemmas (B).
In particular, when - in the (A) case - the 'Key-Word-in-Context' option is selected, the user can automatically access the Concordances tool and check the occurrence contexts of the various items (see below).

A specific button (see below) allows you to import customized lists of key-terms.
Each list to be imported, named MyList.diz, can include up a maximum of 10,000 records (min = 20). Each record of your list must be a single word with no spaces and no punctuation marks.

A model of MyList.diz file is automatically created by T-LAB when saving any your word list (see the appropriate button in the lower left).

The settings of each analysis (up to a maximum of 10) can be saved and restored. That means that the same corpus - without need of further importation - can be analysed with several dictionaries and various word selections (see the "Filing" and the "Restore" options).

T-LAB allows customized settings to be carried out and modified over several sessions, even after operations like Dictionary building.