In this project, the goal is to get familiar with document evaluation criteria and scoring functions. A scoring function assigns a score to the document according to the degree of relevance of a document to the query so that the documents are ranked and displayed based on their score. Finally, the resulting ranking is compared with the grand truth, and the efficiency of the recovery function is reported. The text search tool used in this exercise is Galago.
- Indexing of all documents.
- Applying and familiarizing with available retrieval functions.
- Using evaluation criteria and calculating the effectiveness of evaluation functions.
At first, it is necessary to provide an environment for the project as follows:
- Download and install version 20.4 of the Ubuntu operating system
- Java installation
- Maven Installation
- Galago Installation
First, Connect to the internet.
second install prerequisite,
1- Java
How to install java on ubuntu:
a.sudo apt-get update && apt-get upgrade
b.sudo apt-get install default-jdk
c.java -version :
if (the output is like below, it's in the correct path.): then go to: 2- Maven
output:
openjdk version "11.0.4" 2019-07-16
OpenJDK Runtime Environment (build 11.0.4+11-post-Ubuntu-1ubuntu218.04.3)
OpenJDK 64-Bit Server VM (build 11.0.4+11-post-Ubuntu-1ubuntu218.04.3, mixed mode, sharing)
else:
d.sudo update-alternatives --config java : this give you the jdk path
output :
/lib/jvm/java-11-openjdk-amd64/bin/java
e.sudo gedit /etc/environment
f.if (not exist JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64" at the end of the file)
g.add this line to end of file :
h2.source /etc/environment
e3.echo $JAVA_HOME
output in this step:
"/usr/lib/jvm/java-11-openjdk-amd64"
2- Maven
How to install Maven on Ubuntu:
Notice:the path below is where you have put the downloaded files, like: /home/USER_NAME/Desktop/Galago/apache-maven-3.6.2-bin.tar.gz
a.cp /home/USER_NAME/Desktop/Galago/apache-maven-3.6.2-bin.tar.gz /tmp
b.sudo tar xf /tmp/apache-maven-*.tar.gz -C /opt
c.mv /opt/apache-maven-3.6.0 /opt/maven
d.sudo gedit /etc/profile.d/maven.sh
e.paste the following configuration in file:
export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
export M2_HOME=/opt/maven
export MAVEN_HOME=/opt/maven
export PATH=${M2_HOME}/bin:${PATH}
f.sudo chmod +x /etc/profile.d/maven.sh
g.source /etc/profile.d/maven.sh
h.mvn -v
i.output in this line:
Apache Maven 3.6.2 (40f52333136460af0dc0d7232c0dc0bcf0d9e117; 2019-08-27T19:36:16+04:30)
Maven home: /opt/maven
Java version: 11.0.4, vendor: Ubuntu, runtime: /usr/lib/jvm/java-11-openjdk-amd64
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "4.15.0-65-generic", arch: "amd64", family: "unix"
3- Galago
a.go to galago source folder : cd galago-3.16/
b.enter this command: mvn -DskipTests=true install (notice: it takes 30 minutes)
if (the installation brought up the error about dependency-check-maven 3.3.4):
e1.open pom.xml: gedit pom.xml
e2.find the plugin making the error: (Ctrl+F) 3.3.4
e3.comment the plugin: <!-- -->
e4.go to b.
else:
successful output would be something like this:
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for galago 3.16:
[INFO]
[INFO] galago ............................................. SUCCESS [ 42.601 s]
[INFO] utility ............................................ SUCCESS [ 11.403 s]
[INFO] tupleflow-typebuilder .............................. SUCCESS [ 7.729 s]
[INFO] tupleflow .......................................... SUCCESS [ 4.891 s]
[INFO] eval ............................................... SUCCESS [ 5.547 s]
[INFO] snowball-stemmers .................................. SUCCESS [ 3.615 s]
[INFO] krovetz-stemmer .................................... SUCCESS [ 3.285 s]
[INFO] core ............................................... SUCCESS [ 43.162 s]
[INFO] contrib ............................................ SUCCESS [ 25.643 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 02:28 min
[INFO] Finished at: 2019-10-05T16:54:28+03:30
[INFO] ------------------------------------------------------------------------
c.enter this command: chmod +x core/target/appassembler/bin/galago
d.enter this command: core/target/appassembler/bin/galago
output of this step:
Type 'galago help <command>' to get more help about any command.
Popular commands:
build
search
batch-search
All commands:
batch-search
build
build-entity-corpus
build-special
build-topdocs
build-window
build-word-dates
chain-jobs
doc
doc-id
doc-name
doccount
dump-connection
dump-corpus
dump-index
dump-index-manifest
dump-key-value
dump-keys
dump-modifier
dump-name-length
dump-term-stats
eval
harvest-links
help
make-corpus
merge-index
overwrite-manifest
pagerank
search
stats
stemmer-conflation
subcollection
transform
xcount
e. (optional) you can set an alias for 'galago' in your system to point out to '/core/target/appassembler/bin/galago'
Dataset used in this project consists of three parts:
Collections of news articles are in TREC format. Each document contains several fields:
-
OCNO: ID of each document
-
Head: The title of the document
-
Text: The text of the document
This file contains questionnaires.
This file contains relevant judgments. In the final stage, to evaluate retrieval functions, the obtained results are compared with these judgments.
In any language, words will have different appearances according to the role they play in sentences. But all of them are made from the same root. Therefore, in many methods, we must first find the root of the words. There are different algorithms for stemming; Porter's algorithm is one of the famous algorithms in the English language. According to a series of regular rules (for example, removing the letter s at the end of plural words), this algorithm can obtain the roots of words with good accuracy.
After installing and setting up Galago, we used the Porter Stemmer method to find the roots of words with the help of Galago commands.
"stemmer" : ["porter"]Tokenization converts text into its constituent tokens. We do this with the following commands:
"tokenizer" : {
"fields" : ["text","head"],
"formats" : {
"text" : "string",
"head" : "string"
}
} 
Finally, we extracted the file format, which was initially unformatted with 7zip software from the Windows operating system and reached the .txt file. This type of file is suitable for documents and texts that we need to be able to see different parts of it separately.
We put the commands related to the settings mentioned above in the indexSettings.json file and run the following command in the terminal:
Galago/galago-3.16/core/target/appassembler/bin/galago build /home/arya/Desktop/CA1-Resources/indexSettings.json
After about an hour of executing the Build command, the indexing process was completed successfully.
Done Indexing.
- 0.92 Hours
- 55.18 Minutes
- 3310.79 Seconds
Documents Indexed: 163912.
With the BM25 method, we first perform the retrieval with the default values of b and k on the query set 101 to 150 with the value of 100 for the number of Requested and obtain the values of Recall, MAP, nDCG and P@5. In the following, we change the values of b and k by trial and error first with long steps and note the values every time, and if we see an improvement compared to the default state, we try close values with smaller steps to reach the optimal value.
By searching in scientific sources, the suitable range for the b parameter was 0.3 to 1, and the suitable range for the k parameter was 0.5 to 2.5; based on this, we tested the values in these areas as well as a margin from above and below these areas, and the parameters Optimum for questionnaires 101 to 150 for parameters b and k were seen as 0.4 and 2.6 respectively.
The results obtained from these values were greater than the results obtained from the default values, which indicates that the optimization of these parameters was successful in obtaining better results.
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