HW 2 CS 833 Information Retrieval and Text Mining Fall 2017 Total points: 100 Issued: 09/14/2017 Due: 09/25/2017 Three day late submission is possible, but not encouraged. A late submission incurs a 5% penalty per day. No credit is given to submission more than three days late. Your task is to implement a basic vector space retrieval system. You will use the Cran eld collection to develop and test your system. The Cran eld collection is a standard IR text collection, consisting of 1400 documents from the aerodynamics eld, in SGML format. The dataset, a list of queries and relevance judgments associated with these queries are available from Online K-State. Tasks: To complete this assignment, you need to use the pre-processing tools implemented during assignment 1. Note that you also need to eliminate the SGML tags (e.g., <TITLE>, , , etc.) - you should only keep the actual title and text.

1. Implement an indexing scheme based on the vector space model, as discussed in class. The steps pointed out in class can be used as guidelines for the implementation. For the weighting scheme, use and experiment with: • TF-IDF (do not divide TF by the maximum term frequency in a document).
2. For each of the ten queries in the queries.txt le, determine a ranked list of documents, in descending order of their similarity with the query. The output of your retrieval should be a list of (query id, document id) pairs. Determine the average precision and recall for the ten queries, when you use: • top 10 documents in the ranking • top 50 documents in the ranking • top 100 documents in the ranking • top 500 documents in the ranking Note: A list of relevant documents for each query is provided to you, so that you can determine precision and recall. Submission instructions:
3. write a README le including: • a detailed note about the functionality of each of the above programs, • complete instructions on how to run them • answers to the questions above 1
4. make sure you include your name in each program and in the README le.
5. make sure all your programs run correctly on the CS machines. You will lose 40 points if your code is not running on these machines. The path to the data should be an input parameter, and not hardcoded.
6. submit your assignment through Online K-State.