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Discussion Class 5

Discussion Class 5. TREC. Discussion Classes. Format: Questions. Ask a member of the class to answer. Provide opportunity for others to comment. When answering: Stand up. Give your name. Make sure that the TA hears it. Speak clearly so that all the class can hear. Suggestions:

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Discussion Class 5

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  1. Discussion Class 5 TREC

  2. Discussion Classes Format: Questions. Ask a member of the class to answer. Provide opportunity for others to comment. When answering: Stand up. Give your name. Make sure that the TA hears it. Speak clearly so that all the class can hear. Suggestions: Do not be shy at presenting partial answers. Differing viewpoints are welcome.

  3. Question 1: Objectives The TREC workshop series has four goals: (a) Encourage research in text based retrieval based on large test collections (b) Communication among industry, academia and government (c) Transfer of technology from research labs into products by demonstrating methodologies on real-world problems (d) Increase availability of appropriate evaluation techniques What does the ad hoc task contribute to each of these goals?

  4. Question 2: The TREC Corpus Source Size # Docs Median (Mbytes) words/doc Wall Street Journal, 87-89 267 98,732 245 Associated Press newswire, 89 254 84,678 446 Computer Selects articles 242 75,180 200 Federal Register, 89 260 25,960 391 abstracts of DOE publications 184 226,087 111 Wall Street Journal, 90-92 242 74,520 301 Associated Press newswire, 88 237 79,919 438 Computer Selects articles 175 56,920 182 Federal Register, 88 209 19,860 396

  5. Question 2: The TREC Corpus What characteristics of this data are likely to impact the results of experiments? Explain the statement, "Disks 1-5 were used as training data." Suppose that you were designing two search engines: (i) for use with a library catalog, (ii) for use with a Web search service. How does your data differ from the TREC corpus?

  6. Question 3: TREC Topic Statement <num> Number: 409 <title> legal, Pan Am, 103 <desc> Description: What legal actions have resulted from the destruction of Pan Am Flight 103 over Lockerbie, Scotland, on December 21, 1988? <narr> Narrative: Documents describing any charges, claims, or fines presented to or imposed by any court or tribunal are relevant, but documents that discuss charges made in diplomatic jousting are not relevant. A sample TREC topic statement

  7. Question 3: TREC Topic Statement (a) What is the relationship between TREC topic statements and queries? (b) Distinguish between manual and automatic methods of query generation. (c) Explain the process used by the manual methods. (d) Some of the results used a time limit (e.g., "limited to no more than 10 minutes clock time"). What was being timed?

  8. Question 4: Relevance Assessments (a) Explain the statement, "All TRECs have used the pooling method to assemble the relevance assessments." (b) How is relevance assessed? (c) What is the impact of some relevant documents being missed from the pool? (d) What is the problem of some relevant documents in the pool coming from only a single run? How serious is this?

  9. Question 5: Evaluation

  10. Question 5: What are: (a) The recall-precision curve? The mean (non-interpolated) average precision? The report commented that, "two topics are fundamental to effective retrieval performance." What are they? How do the automatic tests differ from the manual?

  11. Question 6: The future (a) Why was TREC-8 the last year for the ad hoc task? (b) Does this mean that text-based information retrieval is now solved?

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