Written Assignment Two
CSCI 379.01 - Information Retrieval and Web Search
Assigned: September 26th, 2003, Friday
Due: October 3rd, 2003, Friday
This assignment is designed for you to get familiar with the basic
vector model in IR. You are to calculate measures such as
tf-idf and similarity between a
query and a set of documents using different measures, given some
basic statistic about the documents and the terms (key words).
Note: It might be easier to either use a spread-sheet program or write
a program to do the computation and the sorting.
- Table 1 lists the terms and
their appearances in a sub-set of documents.
Table 1:
Term Frequencies In A Given Set Of Documents
| Doc/Term |
retrieval |
database |
computer |
text |
information |
| D1 |
4 |
10 |
2 |
0 |
1 |
| D2 |
3 |
0 |
7 |
4 |
5 |
| D3 |
7 |
2 |
4 |
6 |
8 |
We also know that the total number of documents in the set is
1000. Table 2 shows the document frequencies of these
terms.
Table 2:
Document Frequencies For A Given Set Of Terms
| Term |
retrieval |
database |
computer |
text |
information |
| Frequency |
100 |
70 |
220 |
80 |
110 |
Compute tf-idf for each of the (doc, term) pairs listed in
Table 1. List your
results in sorted order from the largest value of tf-idf to the
smallest value.
- Assume we use the tf-idf as the weight in the vector
model, write down the document-term matrix using the results
generated from the above problem. Remember a document-term matrix
has terms as its columns and documents as its rows.
- Now assume we have a query
computer information
,
compute the similarity based on the inner product similarity and the
cosin similarity for each of the documents listed in Table
1. Which document is the most relevant in each of the
similarity measures? Which one is the least relevant?
Written Assignment Two
This document was generated using the
LaTeX2HTML translator Version 2002-2-1 (1.70)
Copyright © 1993, 1994, 1995, 1996,
Nikos Drakos,
Computer Based Learning Unit, University of Leeds.
Copyright © 1997, 1998, 1999,
Ross Moore,
Mathematics Department, Macquarie University, Sydney.
The command line arguments were:
latex2html -nonavigation -split 1 hw2
The translation was initiated by Meng Xiannong on 2003-09-25
Meng Xiannong
2003-09-25