Arabic Dictionary Compression Using An Invertible Integer Transformation and a Bitmap Representation

An Efficient Compression Scheme For Bitmap Indices

When using an out-of-core indexing method to answer a query, it is generally assumed that the I/O cost dominates the overall query response time. Because of this, most research on indexing methods concentrate on reduceing the sizes of indices. For bitmap indices, compression has been used for this purpose. However, in most cases, operations on these compressed bitmaps, mostly bitwise logical op...

Improved Sequential Pattern Mining Using an Extended Bitmap Representation

The main challenge of mining sequential patterns is the high processing cost of support counting for large amount of candidate patterns. For solving this problem, SPAM algorithm was proposed in SIGKDD’2002, which utilized a depth-first traversal on the search space combined with a vertical bitmap representation to provide efficient support counting. According to its experimental results, SPAM o...

Invertible integer DCT algorithms

Models of Bitmap Generation: A Systematic Approach to Bitmap Compression

In large IR systems, information about word occurrence may be stored in form of a bit matrix, with rows corresponding to diierent words and columns to documents. Such a matrix is generally very large and very sparse. New methods for compressing such matrices are presented, which exploit possible correlations between rows and between columns. The methods are based on partitioning the matrix into...

Data Compression Using a Dictionary of Patterns

Most modern lossless data compression techniques used today, are based in dictionaries. If some string of data being compressed matches a portion previously seen, then such string is included in the dictionary and its reference is included every time it occurs. A possible generalization of this scheme is to consider not only strings made of consecutive symbols, but more general patterns with ga...