Catch up Session

So I haven't been her in a while. I guess it's just me being lazy but I have beeen assigned my project for the year. The project I was assigne was a Sudoku Explainer. It is a program that is supposed to help people to learn how to play sudoku rather than to just complete these games via a brute force search. A link to the prject information page shall now be provided, http://local.cis.strath.ac.uk/teaching/ug/cs4projects/.

Anyway, back to the matter at hand.

Multimedia Information Access - Wednesday 29th September

Boolean Retrieval:

So this was a very easy and simple lecture. It talked about how to deal with searches that were more than one word. A popular way of doing this is to use boolean logic to determine which is best to search for or which terms to ignore.

We watched a video on youtube about a simple boolean search used in some sort of University database. This introduced the concept of boolean operators (which I already know a lot about ;). An extra boolean term was added (purely in terms of searching) and this was NEAR. NEAR basically means taht you want to search for these two words and you want them to be near each other in the text.

Using a Venn diagram the lecturer showed us how these boolean terms can work, however this was not very effective for searches of more than 4 terms as it became almost impossible to include every term in one diagram. Next in an example from the 2009 exam it was shown that when searching for several different terms it was best to search for the term with the fewest reults as this would allow you to quickly get some initial results whilst the rest of the search was being carried out.

Next we went on to cover Conjunctive Normal Form and Disjunctive Normal Form. To put it simply CNF is a Product of Sums term and DNF is a sum of Products term. To convert between these two forms we can use DeMorgan's Law (i.e. break the line change the sign) and then usual distributive laws to work out the new terms. Also, NOT is not allowed to be applied to a group. It must instead only be applied to single terms.

That may not be too clear but it was nearly 2 weeks ago and I have kind of forgotten most of what the guy said.