All posts by Ian Stark

Lecture 12: Corpora

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Slides : Recording

In literature a corpus (plural corpora) is a collection of written texts, in particular the complete works of a single author or a body of writing on a single subject. In computational linguistics and in theoretical linguistics a corpus is a body of written or spoken text used for study of a particular language or language variety. These corpora may be very large (billions of words) and provide the raw material for experimental investigation of real-world language use: the science of empirical linguistics.
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Lecture 11: Navigating XML using XPath

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Slides : Recording

Once we have some semistructured data gathered into an XML tree, we might want to find information within it. For small XML documents we can just look at it, or use text search; for large and very large documents there are dedicated query languages. Today’s lecture presented one of them: XPath, the XML Path Language. As well as being a query language in its own right, XPath is also a key component of many other XML and web technologies, where it is used to navigate around documents.
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New LEGO Computer Scientist Minifig: Margaret Hamilton

Picture of LEGO set
LEGO Women of NASA
LEGO have today announced the latest model to come out of their Ideas fan-design programme. It’s the “Women of NASA” set which includes Margaret Hamilton: computer scientist, software engineer, and leader of the programming team for the Apollo and Skylab space missions.

This goes to complement LEGO’s existing computer programmer minifig. Sadly Lovelace and Babbage didn’t make it this time around.

Links: Announcement; Set design

Hamilton in Apollo Command Module Margaret Hamilton
Software Engineer

Director of Apollo Flight Computer Programming for the moon landings and other NASA missions. CEO, Hamilton Technologies.

Links: Work at NASA; Hamilton Technologies

Tutorial Exercises

Exercises for Tutorial 4 are on the tutorial page. These involve writing and executing SQL queries using the LibreOffice Base desktop application. This is installed on all DICE machines, and the tutorial includes detailed usage notes: using DICE is probably the simplest way to complete the tutorial. It is also possible to do the exercises on university open-access machines or your own computer, and there are some instructions to help with that.

This tutorial includes more substantial starred extension exercises to try out other ways to access the same database.

  1. Setting up queries using the LibreOffice Base graphical query designer.
  2. Connecting on the command-line to a remote PostgreSQL database server.
  3. Linking LibreOffice Base to the remote database server.

Lecture 10: Structuring XML

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Slides : Recording

Every well-formed XML document is neatly arranged as a tree, with names for element nodes and all their attributes. This is enough for basic tools to correctly transmit and process XML; but for many applications it is useful to add more precise domain-specific constraints that we expect documents to satisfy. For this we have XML schema languages: specialised languages for describing types of XML document. This lecture covered one in particular, the Document Type Definition language DTD.
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