Four polyoxometalate (POM) assemblies based on the flexible organic ligand 1,3-bis(4-pyridyl)propane (bpp) 4). Compounds 1 and 2 were prepared by the reaction of the classical Keggin-type anions with organic bpp under hydrothermal conditions. The difference between these compounds is that protonated bpp is found in 1, whereas in 2 Cu I -bpp fragments are present. In the framework of 1, organic and hybrid chains, built upon supramolecular interactions, coexist. Compound 2, which crystallizes in a chiral space group, has a 2D wave-like struc-

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For the convergence speed and scale bottlenecks of evolutionary design of circuits, the paper explores a new evolutionary method on the basis of genetic algorithm. Several optimization methods including fitness sharing, exponential weighting, double selection population, "Queen bee" mating, module crossover and optimal solution set are proposed to improve genetic algorithm.The new algorithm improved fitness evaluation method and genetic strategies. The experiment shows that the new evolutionary algorithm accelerates evolution convergence greatly, improves the adaptability effectively and expands the scale of evolved circuit obviously.

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Current Role-Based Access Control (RBAC) can't assign permissions dynamically and can't update access control policies automatically. In this paper we present a new network access control (NAC) mechanism based on role and behavior (RB-NAC) which enhances role-based access control by establishing clusters of behavior to limit permissions of user dynamically and incorporating an incremental-learning algorithm to update the policies without manual intervention. RB-NAC as an enhanced access control mechanism shows its efficient flexibility and scalability in access control.