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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...
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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

 

Occurrences and Co-occurrences


The Occurrences, in fact, are quantities which result from the computation of how many times (frequences) a single lexical unit (LU)occurs within a corpus or within the context units (CU) in which it is subdivided.


Their distribution can be represented in contingency tables as follows:


Co-occurrences, then, are quantities which result from a computation of how many times two or more lexical units are present together in the same elementary contexts (EC).

Their distribution can be represented in tables such as the following:

With a simple transformation, the "A" type table (rectangular) can be transformed into "B" type (squared and symmetrical) in which for each pair of lexical units the quantity of their co-occurrences is indicated, that is the total number of the elementary contexts in which they are present together.

In T-LAB text analysis is mostly carried out by the study of relationships among occurrences and co-occurrences, either through specific association indexes, or through the use of multidimensional statistical techniques like cluster analysis and correspondence analysis