DNA sequences can be treated as finite-length symbol strings over a four-letter alphabet (A, C, T, G). As a universal and computable complexity measure, LZ complexity is valid to describe the complexity of DNA sequences. In this study, a concept of conditional LZ complexity between two sequences is proposed according to the principle of LZ complexity measure. An LZ complexity distance metric between two nonnull sequences is defined by utilizing conditional LZ complexity. Based on LZ complexity distance, a phylogenetic tree of 26 species of placental mammals (Eutheria) with three outgroup species was reconstructed from their complete mitochondrial genomes. On the debate that which two of the three main groups of placental mammals, namely Primates, Ferungulates, and Rodents, are more closely related, the phylogenetic tree reconstructed based on LZ complexity distance supports the suggestion that Primates and Ferungulates are more closely related.
A new method to prepare micro-nanopowder with incorporating jet milling and electrostatic dispersion was presented in this study. The dispersivity of the powder could be improved during the process of jet milling by having the particles charged with identical charge. Both micro-nanopowders with high dispersion, calcium carbonate (CaCO3) and magnesium zinc ferrite (MgZnF) were prepared respectively. The theoretic studies on this method and the analyses on the effects of preparation parameters on dispersivity, showed that jet milling /electrostatic dispersion (J/E) method to prepare micro-nanopowder in the air without any additive is achievable. The charge voltage and air current pressure would strongly affect the characters of the powder. The charge to mass ratio (q/m) of both powders reached its peak under the charge voltage at 50 kV and air current pressure at 0.3MPa.
In the last years, the deployment of embedded real-time communication systems has increased dramatically. At the same time, the amount of data that needs to be managed by embedded real-time main memory databases is increasing, thus requiring an efficient data management. However, system crash will cause data loss in main memory, which will seriously affect the normal operation of the entire communication system. This paper introduces an algorithm of system crash recovery applied in main memory database of embedded real-time communication system. This paper expatiates the software architecture of SDR base station, the cause of crash occurring, and proposes the flash recovery algorithm using for system recovery. A main memory database using this algorithm has been applied in a real communication systemmultimode SDR base station communication system.
The competitive price model is applied in the analysis of spectrum sharing in cognitive radio networks. As the prices of shared spectrum are determined independently by primary users in practical application, to deal with the solution of equilibrium price without acknowledgement of current price strategies from other primary users, the iterative method is used to calculate price of the shared spectrum. In order to achieve better characteristics, an exponential iterative method for the competitive price based spectrum sharing model is proposed. It can achieve the desired spectrum price only with the prices strategies during last iteration. Simulation results show that the proposed exponential gradient iterative scheme can achieve the equilibrium price that maximizes the profits of primary users, and have better convergence performance than linear gradient iterative scheme.
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