Attacks, especially geometric attacks, can destroy the synchronization relationship of the watermark embedding and extraction, causing difficulties in detecting and extracting watermark.
However, some design factors such as lack of reliable minutia extraction algorithms, difficulty in quantitatively defining a reliable match between fingerprint images, poor image acquisition, low contrast images create bottlenecks in achieving the desired performance.
Substantial inaccuracies in administrative data are common, which leads to expensive data extraction and difficulty in validating data [ 1- 3].
Based on this classification, the difficulty of extraction was evaluated using difficulty index described by Pederson [6].
Soluble sugars could not be quantified after extraction due to difficulties in resolving distinct peaks using the high-performance liquid chromatography (HPLC) and were therefore not included in the composition.
The results of this study demonstrate that even when high quality DNA from fresh blood extractions is available, difficulties in establishing the correct organellar mtDNA sequence may be encountered.
Currently, these residues are disposed of by burning or shredding, not being exploited because of several technical difficulties in extraction, handling and transport as well as because of the lack of accurate data on the quantity and suitability of these residues.
Tetracyclines are among the main antimicrobials used in aquaculture, and present a particular difficulty for extraction, due to a complex structure and high interaction with components of the biological matrix.
Microbial production of glycerol has been known for 150 years, and glycerol was produced commercially during World War I. Glycerol production by microbial synthesis subsequently declined since it was unable to compete with chemical synthesis from petrochemical feedstocks due to the low glycerol yields and the difficulty with extraction and purification of glycerol from broth.
