LDPC (low density parity check code) is one of the most excellent codes,and it is a strong competitor of the fourth generation communication system (4G) as its performance is close to Shannon transmission limit.The paper realizes LDPC encoding and decoding algorithm through Verilog to improve computational efficiency,and selects π rotation matrix construction method to encode.And queen algorithm avoids the appearance of Cyclotella in H matrix.The UMP BP-based algorithm is also used in decoding and all of decimal fractions are limited between -100 and 100.For a large number of decimal fractions,the Q8 (fixed-point) format is adopted to express them and the range is between -128 and 127.996 093 75 with the precision of 0.003 906 25.Thus floating-point arithmetic can be avoided and Verilog language can be used to describe the LDPC decoding algorithm.The program does not use any IP core,which means it can be applied to all FPGAs and has good transplantation.It has high application value in engineering. 相似文献
ABSTRACT Agrobacterium tumefaciens-mediated transformation with plasmids carrying the hygromycin B resistance gene hph frequently is being used for inserting genes into fungal spores and mycelial cells and for conducting insertional mutagenesis to identify genes connected to a particular phenotype. In this article, we report that stable hygromycin B resistance can develop spontaneously in germinating conidia from Monilinia fructicola and that the mutants exhibit altered phenotypes. One spontaneously developing hygromycin B-resistant colony developed per 2.5 x 10(5) germinating conidia. Mutants grew significantly slower on potato dextrose agar, were 2.4- to 3.1-fold more sensitive to demethylation inhibitor fungicides, lacked melanization, and did not produce spores. The mode of action of hygromycin B resistance in the mutants seemed to be different from the hph transgene-mediated hygromycin B resistance based on different phenotypic characters. The ability of M. fructicola and possibly other fungi to spontaneously develop hygromycin B resistance associated with an altered phenotype may interfere with the selection of true transformants if hygromycin B is used as selective agent. This is particularly confounding if the hph gene is used as selectable marker in insertional mutagenesis experiments conducted for the identification of genes involved in melanization, sporulation, or fungicide resistance. 相似文献
Fisheries Science - Molting is a critical developmental process for crustaceans, during which the claw muscles undergo periodic atrophy and restoration. The regulatory mechanism of this special... 相似文献