Practice

The world most biggest Library

CIMI

My seminar on CIMI

How Search engines works "Link"

Seminar-Probabilistic Retrieval Model

Probabilistic Retrieval Model

Probabilistic theory has been used for modelling the retrieval process in mathematical term.In conventional retrieval situation a document is retrieved whenever the keywod set is attached to document set apears similar to the keyword query.In that case the document is consider as relevant to the query. So relevance is a matter of degree and it can be postulated that when the document and query vector are sufficiently similar. the basic tenet of this approach is that for optimal performances. documents should be ranked in order of decreasing probability of relevance to the user. Probabilistic aproaches attempt to calclate the probability that a document will be relevant to the user.Several modes are there for this purpose., here we shall breifly look ninto 3 such models

Marons and Kuhns model

they proposed that the probability that a document relevant to a user can be assesed by the calculaton of Probability, for each document in collection,that user submitting perticular query term would judjed the document relevant

Robertson and Sparck jone Model

In this model the probability that a document can be calculated not for set of user employing perticular query term, but for a set of document having the property in relation to a given user.

Salton and McGill Model

This model takes a diferent aproach, the essence of this model is that it tells us the retieved item whether it is relevant or not, it depends on two basic parameter . it has 2 cost parameter and loss factor . it gives the total loss for a retrieval process..

Reference:

Chowdary.C. G.1999.Introduction to Modern Information Retreval.London:Library Association Publication.

ASSIGNMENT

COMPARISON BETWEEN 2 I R MODEL
1,Firsst model is complicated than second model
2,In second model pop of doc&sel doc are thereas input .but in 2 model only text obj is there
3,In 1 mod conc anal &trans are the 2steps ussed for indexing .But in 2 mod only indexed obje are taken
along with repr steps
4,In 1mod out put steps are similar to the input(usr put a request ).samethings are happened in 2 mod
( a user put a query )
5, In 1mod it searches for users needed infn in its indexing rec ,In 2 mod it compare the users query with
its indexed obj
6,In 1 mod search strategies indexing records system vocccabulary .data base of doc repre given us the
more infn about the I R process ,Than in 2 mod , because 2 mod didnot consist to much of component
in its model
7,In 1 mod users can accessthe infn directly through doc repre steps ,If he knew the search strategies ,but
this is not shown in 2 mod
8,In 2 mod it can take out the infn without comparison steps &it also can evaluate &put infn to the user ,
these steps are not shown in 1 mod
9,Both mod are holds good to any application or example of I R system
10,Both mod are similar except some points mentioned above
NOTE:
Here 1mod is "Major func of infn services" & 2 mod is "Simple flow of retre system"

sorry sir

Seminar

CANON OF RELEVANT SUCCESSION The succession of the characteristics in the associated scheme of characteristics should be relevant to the purpose of classification EXAMPLES: 1),DECIMAL CLASIFICATION In DC, Language, Form , Period and Author are the three characteristics used in classifying the universe of subjects going with the main class literature. There are six different succession in which these three characteristics can be used. But DC has rightly chosen the succession: Language, form, period, and Work as most relevant to the purpose of classification of books –which is the convenience of the readers. 2), COLON CLASSIFICATION a) In, CC, Language, Form, Author, and Work, are the four characteristics used in classifying the same universe of subjects. Out of twenty-four succession possible, CC has rightly chosen the succession: language, Form, Author, and Work as most relevant. The implications of the choice in shelf arrangement are fully discussed in the CC b) Substance and Problem are two characteristics used in classifying the universe of subject going with the main class Chemistry, In Ed 1(1933) the succession prescribed for these characteristics was: Problem, Substance, While doping reference service on floor duty , it was found that this succession did not give the satisfaction to readers In other words , it was not relevant to the purpose of the readers, Therefore, their succession was changed into Substance, Problem, in Ed 2(1939) Reference: Ranganathan, S. R. Prolegomena to Library Classification. 3rd ed., New Delhi: Asia Publishing House, 1967.