CS 6999 Semantic Web Techniques |
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Assignment 2 |
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Hints: You may want to use j-DREW from Lab 2 to help
you decide some of these questions and to check your answers. You may want to use a Prolog system
such as http://clip.dia.fi.upm.es/Software/Ciao/
or http://www.swi-prolog.org/. All questions are to be answered. This assignment is due Oct 10, to be
handed in at the beginning of class. 1.
Express in Prolog
clauses that custard with caramel sauce that has been glazed is called crème
brulée. Thus you will use
the name creme_brulee. 2.
Assume that a person
seeks serving suggestions for crème brulée
and uses search keywords “caramel” and “glazed”. Define clauses so that a smart search engine can use your
clauses to find web pages about_creme_brulee, even if the
web pages do not mention glazing explicitly. Assume the search engine places an “and” condition between
keywords. 3.
Suppose that a smart
search engine is used for route planning. Further suppose a web site for Acadian Lines mentions that
it connects Sydney to Truro on one route and Truro to Amherst on
another. Finally suppose that
there is an SMT Bus connection from Fredericton to Sussex and from Sussex to
Amherst. Express these
statements in Prolog clauses: a.
The relation connected_to_via_Acadian_Lines is a special case of connected_to. b.
The relation connected_to_via_SMT is also a special case of connected_to. c.
The relation connected_to is transitive and symmetric. 4.
Give a Prolog
derivation proving that Sydney is connected to Fredericton, and give another
showing that Fredericton is connected toSydney. For your derivation you may use a suitably abbreviated
version of the tree that j-DREW gives. (For example, the right hand side of
each rule is duplicated, once showing with the head and once again indented
below – so in your derivation give just the indented one of these.) 5.
What problem(s) can
arise when explicitly creating all of the connected_to facts
implied by your connected_to rules, using Prolog’s strategy of applying rules in
textual order and selecting goals in left-to-right, depth-first order? For each problem discuss what
solutions can you propose. Please
discuss at least two problems. 6.
Showing that the
connection exists is not very useful. It is important for a person to know
the route to take. Adjust your rules for connected_to so
that the route is listed in another argument, suitably referred to within a structure
analogous to the Embedded Struct Element referred to on page 62 of Notes. You may using multiple levels of
nesting within the structure. |
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Maintained by Bruce Spencer