[SOLVED] C html XML XML and Structured Information: Coursework 2 Deadline: 6th of December at 10:00 AM

XML and Structured Information: Coursework 2 Deadline: 6th of December at 10:00 AM
This coursework involves writing some XQuery expressions to extract useful information from some real XML data. The coursework must be performed individually.
Download the example files cw2files.zip. These are real datafiles from the British National Corpus, a collection of English language data widely used by linguists and computational linguists, together with a schema. There is a full explanation of the schema1, but the important parts here are:
represents a sentence, containing possibly many children representing words in linear order;
YYYrepresents word YYY. A 5 marks
Produce a extract.xquery file containing a XQuery FLWOR expression which returns all the oc- currences of the word has in the collection of files, together with the word which comes next in the sentence in each case. The resulting list should be formatted as a HTML table, with each row containing the two words in their own cells, e.g.:
Hints You can use the collection() function to load all the corpus files together. The XML files
often contain capital letters and stray whitespace within the element text values, so the normalize-space() and lower-case() XPath functions may be useful.
B 5 marks
The results from A will contain many duplicates. Produce another version (freqs.xquey) which returns only unique results, together with the number of times this combination of words occurred, sorted in descending order of frequency:
1 http://www.natcorp.ox.ac.uk/docs/URG.xml?ID=bnctags
Target
Successor
has
there
has
nt
has
nt

Hints You can use the distinct-values() function to obtain only unique values from a se- quence. You can intersperse let and for clauses in XQuery, and the right-hand-side of either can itself be a FLWOR expression.
C 5 marks
Corpus linguists are often interested in finding whether pairs of words occur together more often than would be expected by chance (these are called collocations). Produce a modified version of your query from B (probs.xquery) which replaces the simple frequency count with the probability that the successor word occurs after the target. You can calculate this probability as the ratio: (number of times successor word appears after target) / (number of times successor word appears overall).
Hints To divide one number by another in XPath, use the div operator, not the / symbol. D 5 marks
Youll notice that the results from C have a long tail a large number of words with low probabilities of co-occurrence (mostly words which are just quite common, so they appear often after the target word has, but only because they appear quite often anyway). Produce a final version (top20.xquery) which limits the number of results to the top 20 (i.e. the first 20 results returned in C).
E Submission
You have to submit a single file in a zip folder. Your submission has to include the following files:
extract.xquery freqs.xquery
probs.xquery
top20.xquery
Target
Successor
Probability
has
begun
1

has
gained
0.67

2