Text REtrieval Conference (TREC)
System Description

Organization Name: Saarland University Run ID: lsv2007c
Section 1.0 System Summary and Timing
Section 1.1 System Information
Hardware Model Used for TREC Experiment: cluster nodes
System Use: DEDICATED
Total Amount of Hard Disk Storage: 300 Gb
Total Amount of RAM: 4000 MB
Clock Rate of CPU: 2660 MHz
Section 1.2 System Comparisons
Amount of developmental "Software Engineering": NONE
List of features that are not present in the system, but would have been beneficial to have: fine grained named entity recognition
List of features that are present in the system, and impacted its performance, but are not detailed within this form:
Section 2.0 Construction of Indices, Knowledge Bases, and Other Data Structures
Length of the stopword list: 4 words
Type of Stemming: PORTER
Controlled Vocabulary: YES
Term weighting: NO
  • Additional Comments on term weighting:
Phrase discovery: YES
  • Kind of phrase: noun phrase
  • Method used: SYNTACTIC
Type of Spelling Correction: NONE
Manually-Indexed Terms: NO
Proper Noun Identification: YES
Syntactic Parsing: YES
Tokenizer: YES
Word Sense Disambiguation: NO
Other technique: NO
Additional comments:
Section 3.0 Statistics on Data Structures Built from TREC Text
Section 3.1 First Data Structure
Structure Type: N-GRAMS, SUFFIX ARRAYS, SIGNATURE FILES
Type of other data structure used:
Brief description of method using other data structure:
Total storage used: Gb
Total computer time to build: hours
Automatic process: YES
Manual hours required: hours
Type of manual labor: NONE
Term positions used: NO
Only single terms used: YES
Concepts (vs. single terms) represented: NO
  • Number of concepts represented:
Type of representation:
Auxilary files used: YES
  • Type of auxilary files used: LM-based toolkit developed by LSV groups
Additional comments:
Section 3.2 Second Data Structure
Structure Type: N-GRAMS, SUFFIX ARRAYS, SIGNATURE FILES
Type of other data structure used:
Brief description of method using other data structure:
Total storage used: Gb
Total computer time to build: hours
Automatic process: YES
Manual hours required: hours
Type of manual labor: NONE
Term positions used: NO
Only single terms used: YES
Concepts (vs. single terms) represented: NO
  • Number of concepts represented:
Type of representation:
Auxilary files used: YES
  • Type of auxilary files used: Lucene toolkit
Additional comments:
Section 3.3 Third Data Structure
Structure Type:
Type of other data structure used:
Brief description of method using other data structure:
Total storage used: Gb
Total computer time to build: hours
Automatic process:
Manual hours required: hours
Type of manual labor: NONE
Term positions used:
Only single terms used:
Concepts (vs. single terms) represented:
  • Number of concepts represented:
Type of representation:
Auxilary files used:
  • Type of auxilary files used:
Additional comments:
Section 4.0 Data Built from Sources Other than the Input Text
Internally-built Auxiliary File

File type: KNOWLEDGE BASE
Domain type: DOMAIN INDEPENDENT
Total Storage: Gb
Number of Concepts Represented: concepts
Type of representation: FRAMES
Automatic or Manual: AUTOMATIC
  • Total Time to Build: hours
  • Total Time to Modify (if already built): hours
Type of Manual Labor used: NONE
Additional comments:
Externally-built Auxiliary File

File is: WORDNET
Total Storage: Gb
Number of Concepts Represented: concepts
Type of representation: SEMANTIC NETS
Additional comments:
Section 5.0 Computer Searching
Average computer time to search (per query): CPU seconds
Times broken down by component(s):
Section 5.1 Searching Methods
Vector space model: YES
Probabilistic model: YES
Cluster searching: NO
N-gram matching: YES
Boolean matching: NO
Fuzzy logic: NO
Free text scanning: NO
Neural networks: NO
Conceptual graphic matching: NO
Other: NO
Additional comments:
Section 5.2 Factors in Ranking
Term frequency: YES
Inverse document frequency: YES
Other term weights: NO
Semantic closeness: YES
Position in document: NO
Syntactic clues: YES
Proximity of terms: NO
Information theoretic weights: NO
Document length: NO
Percentage of query terms which match:
N-gram frequency: YES
Word specificity: NO
Word sense frequency: NO
Cluster distance: NO
Other: NO
Additional comments:
Section 6.0 Query Construction
Section 6.1 Automatically Built Queries for Ad-hoc Tasks
Topic fields used:          
Average computer time to build query    CPU seconds
Term weighting (weights based on terms in topics): NO
Phrase extraction from topics: NO
Syntactic parsing of topics: NO
Word sense disambiguation: NO
Proper noun identification algorithm: NO
Tokenizer: NO
  • Patterns which were tokenized:
Expansion of queries using previously constructed data structures: NO
  • Comment:
Automatic addition of: NONE
Section 6.2 Manually Constructed Queries for Ad-hoc Tasks
Topic fields used:        
Average time to build query?   minutes
Type of query builder: OTHER
Tool used to build query: NONE
Method used in intial query construction? BOOLEAN CONNECTORS
  • If yes, what was the source of terms?
Total CPU time for all iterations:  seconds
Clock time from initial construction of query to completion of final query:   minutes
Average number of iterations:
Average number of documents examined per iteration:
Minimum number of iterations:
Maximum number of iterations:
The end of an iteration is determined by:
Automatic term reweighting from relevant documents:
Automatic query expansion from relevant documents:
  • Type of automatic query expansion: ALL TERMS IN \
Other automatic methods:
  • Other automatic methods included:
Manual methods used:
  • Type of manual method used: NONE
Send questions to trec@nist.gov

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