This paper presents an improved genetic algorithm to solve the materialized view selection problem under query cost constraints. The algorithm dynamically changes the crossover probability and mutation probability in the process of genetic. In this way, it can not only maintain the population diversity, but also ensure the convergence of the genetic algorithm. So it effectively improves the opt...

Domain analysis typically results in the construction of a domain-specific repository. Such a repository imposes artificial boundaries on the sharing of similar assets between related domains. A lattice-based approach to repository modeling can preserve a reuser’s domain specific view of the repository, while avoiding replication of commonly used assets and supporting a more general perspective...

The received view of the meaning of time reversal in quantum mechanics suffers from a problem of conventionality. I review existing attempts by philosophers to avoid this problem, and argue that they fall short. In their stead, I propose an alternative approach to the meaning of time reversal in quantum theory inspired by Wigner. In particular, I show that a refinement of Wigner’s assumptions g...