Fast searching over compressed text using a new coding technique: tagged sub-optimal code (TSC)

2005

Real-Time Syst

This paper presents Tagged Sub-optimal code (TSC), a new coding technique to speed up string matching over compressed databases on personal digital assistants (PDA). TSC is a variable-length sub-optimal code that supports minimal prefix property. It always determines its codeword boundary without traversing a tree or lookup table. TSC technique may be beneficial in many types of applications: speeding up string matching over compressed text, and speeding decoding process. This paper also presents two algorithms for string matching over compressed text using TSC (SCTT) and the Byte Pair Encoding (BPE) technique (SCTB).Several experiments were conducted to compare the performance of TSC, Byte Pair Encoding (BPE), and Huffman code. Several PDA databases with different record sizes were used: the well-known Calgary dataset and a set of small-sized PDA databases. Experimental results show that SCTT is almost twice as fast as the Huffmanbased algorithm. SCTT has also the same performance in search time as the search in uncompressed databases and is faster than the SCTB algorithm. For frequently updated PDA databases such as phone books, to-do list, and memos, SCTT is the recommended method regardless of the size of the average record length, since the time required to compress the updated records using BPE poses significant delays compared to TSC.

Section: Tagged Sub-optimal Code (Tsc)mentioning

confidence: 99%

String Matching Over Compressed Text on Handheld Devices Using Tagged Sub-Optimal Code (TSC)

2005

Real-Time Syst

“…Tagged Sub-optimal code (TSC) is a new suboptimal coding technique that always determines its codeword boundary without traversing a tree or lookup table, which can be used as general-purpose compression scheme [11]. The codewords are generated based on traversing a binary tree and the lengths of the codes are variable-length depending upon the number of codes represented (2 to 14 bits long for 254 codes).…”

Section: Tagged Sub-optimal Code (Tsc)mentioning

confidence: 99%

“…Therefore, String matching over compressed databases on PDAs is essential since memory is at a premium. The compression techniques nominated in this research are the Byte Pair Encoding (BPE) [7] and the Tagged Suboptimal Code (TSC) [11 ]. The rest of this paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of prefix and non-prefix codes in string matching over compressed databases on handheld devices

Proceedings of the 2005 ACM Symposium on Applied Computing

2005

This paper shows the efficiency of prefix and non-prefix codes for searching over compressed handheld databases. Byte Pair Encoding (BPE), Tagged Suboptimal Code (TSC), and Huffman encoding are the compression techniques used in the evaluation. By compressing handheld databases and searching over compressed text without needing to expand the databases, more data will be stored and more applications can be used. Experimental results show that about 33% more space has been achieved in the compressed handhelds' databases when using Searching over Compressed Text using BPE (SCTB) or Searching over Compressed Text using TSC (SCTT) solutions. Moreover, both solutions are 6.6 times faster than decompressing the databases followed by a linear search in all different sizes of databases. Efficiency performance shows that SCTB is the recommended solution for databases consisting of large-sized records and rarely updated, and SCTT is the recommended method for frequently updated databases or consisting of smallsized records. TSC and BPE compression schemes could also be used to accelerate wireless connectivity, web clipping, or databases transfer between handheld devices and computers, since these databases are usually small in size.

“…Tagged Sub-optimal code (TSC) is a new proposed coding technique that can be used as a general-purpose compression scheme [30]. TSC coding technique has many features such as speeding up string matching over compressed text, fast decoding, and fast encoding.…”

Section: Tagged Sub-optimal Code (Tsc)mentioning

confidence: 99%

Speeding up string matching over compressed text on handheld devices using tagged sub-optimal code (TSC)

Proceedings. RTAS 2004. 10th IEEE Real-Time and Embedded Technology and Applications Symposium, 2004.

Self Cite

Tagged Sub-optimal code (TSC) is a new coding technique presented in this paper to speed up string matching over compressed databases on PDAs. TSC is a variable-length sub-optimal code that supports minimal prefix property. It always determines its codeword boundary without traversing a tree or lookup table. TSC technique may be beneficial in many types of applications: speeding up string matching over compressed text, speeding decoding process, as well as any general-purpose integer representation code. Experimental results show that TSC is 8.9 times faster than string matching over compressed text using Huffman encoding, and 3 times faster in the decoding process. On the other hand, the compression ratio of TSC is 6% less than that of Huffman encoding. Additionally, TSC is 14 times faster than Byte Pair Encoding (BPE) compression process, and achieves better performance than searching over compressed text using BPE scheme on handheld devices.