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Introducing XAIRA

XAIRA is a tool which can be used to explore any kind of XML corpus (not necessarily TEI!) in various ways. This document lists in simple form some simple suggestions to get you started using this tool. More detailed instructions (including screen-shots) about how to use XAIRA with the BNC are on the BNC Website at Using the BNC XML Edition with XAIRA page. Full details about XAIRA are available in the XAIRA reference manual (which you can read online or access in the XAIRA client).

1. XAIRA architecture

XAIRA (XML Aware Indexing and Retrieval Architecture) is a complex system for indexing and searching large quantities of XML data. This exercise uses two parts of it only: the Windows tool kit, and the Windows client. There are other components for other platforms or environments, e.g. for developing web-hosted applications using PHP or Java. See http://www.xaira.org for details.

XAIRA is an open source project developed at OUCS for use initially with the BNC (http://www.natcorp.ox.ac.uk).

2. Getting started

Before you can start exploring the BNC XML with XAIRA you need to install the software and index your corpus. XAIRA will index a corpus which has almost any level of XML markup, including none at all. For this exercise, we'll use a version of the Punch files we have prepared which includes some automatically-generated linguistic markup.

In these files we have marked up the word boundaries using the <w> XML element. As well as allowing us to tokenize the text explicitly, this also allows us to annotate each word with a part of speech and a root form, using attributes type and lemma respectively. This was done using a freely available tagging program called tree tagger (also included on your USB key); tree tagger also enables us to identify sentence divisions automatically in the text, with moderately successful results. These are useful for delimiting searches and giving us rather more accurate reference information, as we will see.

  1. Start up the XAIRA TOOLS application
  2. Select `Index Wizard' command from the File menu
  3. The Corpus Name dialog opens. Enter a name for your corpus ("Punch" for example), and a description of the corpus if you like. Press NEXT to continue.
  4. The Corpus Root dialog opens. Press NEXT to continue.
  5. The Texts dialog opens. Press BROWSE and navigate to the Work folder (or wherever you unzipped the archive). Select the folder named Wtexts inside Xaira in this archive. Press NEXT to continue.
  6. The Markup dialog opens. Decision time! Select the radio button "XML".
  7. The File Structure dialog opens. Choose Model 1 and press NEXT to continue with the default options.
  8. The File list dialog opens. You could select one or two files only here, but by default we will index the whole lot. Press NEXT to continue.
  9. The Reading files dialog opens. Press GO to validate the files: there should be no errors. Press NEXT to continue.
  10. When the Language dialog opens, pick the appropriate language from the list (en) and press NEXT to continue.
  11. The next few questions determine how lines of context taken from corpus texts are to be identified or referenced by the client. For each context in a concordance window, XAIRA will construct a reference identifying its location. This has at least two parts: the text identifier and one or more unit identifiers.
  12. On the Text Delineation dialog, check the box that says "Just use file names". Press NEXT to continue.
  13. On the Unit Delineation dialog select the element s from the scrolling list on the left, and select the Auto-number from the window on the right. Press NEXT to continue.
  14. On the Word Delineation dialogue, select the <w> element and press NEXT.
  15. The Additional Keys dialogue opens: the default keys identified by the wizard are the attributes type and lemma. Press NEXT to continue.
  16. The Bibliography dialogue appears; we haven't prepared this for you, so press NEXT to continue.
  17. The Indexing dialog appears as before. For this corpus, we need to take one more step which the Wizard cannot help us with. Do not press Index yet! Instead, press Cancel to close the wizard.
  18. The Corpus Wizard cannot do everything. The XAIRA Tools utility allows you to fine tune almost all aspects of your corpus indexing. We will demonstrate this by defining what XAIRA calls a lemma scheme for your corpus. Proceed as follows:
    • In XAIRA Tools, select `LemmaSchemes' from the Tools menu. The Lemma Schemes dialog opens.
    • Press Add to create a new lemma scheme: a second Lemma scheme dialog box opens.
    • In the Name box, enter "TT" for the lemmatization scheme
    • In the Gloss box, enter "Tree Tagger", since this is the agency solely responsible for this lemmatization scheme
    • Choose lemma from the list of available additional keys and press the Add button to add it to the lemma scheme
    • Press OK to return to the first Lemma Schemes dialog, and press OK again.
    • One further step is necessary to cope with the way the OUCS lecture room machines are set up. Select Indexer/Options to open the indexer options dialog. Uncheck the box that says Calculate location buffer size automatically. Enter a suitable size for this buffer (we suggest 3000000).
    • You are now ready to index your texts. Select Indexer/Run from the Tools menu.
  19. When indexing is complete, start the XAIRA client, select Open from the File menu, and navigate to the xcorpus file created in My Corpora\Punch to open it.

3. Exploring the corpus with XAIRA

3.1. Basic search

Use the search box on the XAIRA toolbar to search for german. Download just the first 100 solutions, or a random selection.

3.2. Display of solutions

  1. Toggle between Page mode and Line mode (Use the Page/line mode button )
  2. Display more context. (Use Scope list and change to 2)
  3. Display the XML (Use the Format list , select XML) .
  4. You can also make your own stylesheet to display things in different ways.
  5. Sort the lines on the word immediately following the search word (Use Sort button. Key: One; Sort Key: Right, Ascending, Span 1. Tick ‘Use text’, Collating: Primary).

3.3. Collocation

The collocation feature allows you to see what co-occurs with a particular search term.

  1. Use the Collocation button to retrieve the collocations of your search word. Tick the ‘Controls’ box (bottom of collocation window). (Use the Collocations function. Untick 'Downloads only'. Set window 0L 1R)
  2. Select the ‘Window’ tab and set the span to Left 3 Right 3. Click ‘calculate’. Explore the result.
  3. Click the colligation tab, tick ‘colligation’ and select TYPE. Explore result.
  4. Try some other words (such as "English" or "French") to see if they have similar collocation patterns.

3.4. More search options

XAIRA offers a wide range of search options. You can make the same search in different ways. You can also combine different kinds of searches.

Include part-of-speech and/or lemma information for search term
Use the Word Query command: tick boxes ‘Controls’ and ‘Unique forms’ at bottom of window) . Type ‘round’ in the search box and click ‘Lookup’. Click on the word ‘round’ in the result list and see what is displayed in the bottom window (= different word-class tags available with ‘round’). Look for lemma information: Select the ‘Lemmata’ tab (in right-hand part of window). Choose ‘tt’ from the drop-down menu. What happens in the left-hand part of the window? Click on a word in the top window and explore the result in the bottom one.
Search by regular-expression
Find a list of all four-letter words in the corpus using the regular-expression tickbox in Word Query
Search by regular-expression
Find all occurrences of four-letter words in the corpus using the Pattern Query)
Search by word-class information
Use the Addkey query. Tick the ‘Any’ box. Click ‘Refresh’ to display all available part of speech tags. Select the one(s) you want to search for and click OK (select more than one by pressing the CTRL-key on your keyboard while you click).
Search XML markup
Use XML Query to do markup-sensitive queries. For example:
  • Look for <name> elements. Sort them by the right 3 words.
  • Find what values have been assigned to the type attribute on <div>
Combine search options
Use the Query Builder to find ...
  • sentences containing three consecutive adjectives
  • occurrences of ‘dog’ and ‘canadian’ within 10 words of each other

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