Information Retrieval Models and their Applications

1) What do you understand by Information Retrieval?
Information Retrieval is a process of selecting information from a store.

2) What are the different Information Retrieval techniques?
Information retrieval techniques are broadly categorized into three types:
i) Exact match retrieval:
ii) Best match retrieval
iii) Partial match retrieval.

3) Discuss briefly the various Retrieval Models.
There are three basic information retrieval models.
i) Data Retrieval Model – It essentially handles data and can be taken as unprocessed information or preliminary phase of information. Census system is a data retrieval system.
ii) Information Retrieval Model – It is data oriented to a purpose. It combines several data: into a relational structure.
iii) Knowledge Retrieval Model – It assimilates several types of information in order to facilitate decision-making and problem solving. It is a sophisticated model of information processing and organisation.

4) Write down the different Information Retrieval Models based on theories and
tools.
The different information retrieval models based on theories and tools are:

1. Boolean Retrieval Model (Standard and Weighted)
2. Fuzzy Logic Model
3. Set Theoretic Model
4. Vector Space Model
5. Probabilistic Retrieval Model
6. Linguistic Model
7. Mathematical Model
8. Psychological Model
9. Economic Model
10. Hypertext Linkage Model

KEYWORDS
Anomalous State of Knowledge (ASK) : Lack of a particular fact in the information seeker’s knowledge base, it may represent a much larger area of missing information, or it may represent a lack of knowledge structure.
Fuzzy Retrieval : The capability to locate spellings of words that are similar to the entered search term. Fuzzy retrieval increases recall and decreases precision. In the process of expanding a query term, fuzzy retrieval includes other terms that have similar spellings. This function is primarily used to compensate for errors in spelling of words.
Retrieval Status Values (RSVs) : In retrieval process, the query description and  document descriptions are matched and a score is generated for every document pair. These scores are called Retrieval Status Values (RSVs).
Weighting : Weighting is the process of assigning an importance to an index term’s use in an item.
The weight represents the degree to which the concept associated with the index term is represented in the item. In a weighted indexing system, an attempt is made to place a value on the index term’s representation of its associated concept in the document.

Source: IGNOU Study Material