Domain-Oriented Subject Aware Model for Multimedia Data Retrieval

Algorithm 1

Subject aware query expansion algorithm.

Input: A subject aware graph 𝐺, user query threshold 𝛼, 𝛼>0, input query keywords 𝑄𝐾

Output: Expansion result set 𝐶𝑅

(1) Initialize the result set 𝐶𝑅 to 𝑛𝑢𝑙𝑙.

(2) Match between 𝑄𝐾 and the SN in the 𝐺 to get SK;

(3) If (𝛼>1) then search the corresponding results.

   (a) Search all the SN whose parent node is the same with the parent node of SK and save them;

   (b) Find the SN which satisfies the Rule 1, and rank the SN according to the difference between its SA and the SA of SK;

   (c) Save the sequence number of ranking as CR.id, the name of SN as CR. expansion;

(4) search the corresponding results according to 𝛼≤1

   (a) If (SK. 𝑛_𝑠==null) then   (i) find the IN in the 𝐺 which satisfies the Rule 2, and rank the IN

               according to the IA of IN;

                 (ii) Save the sequence number of ranking as CR.id, the name of IN as CR. expansion;

   (b) else                  (i) Search all the SN in the G whose parent node is SK and save them to a set;

                (ii) Find the SN which satisfies the Rule 3 from the set, and rank the SN according to

               the SA of SN;

                (iii) Save the sequence number of ranking as CR.id, the name of SN as CR. expansion;

(5) Return 𝐶𝑅.