W hen the Internet Engineering Task Force approved Internet protocol version 6 several years ago, proponents acclaimed it as a major development. Since then, IPv6 (see the sidebar " IPv6 Primer ") has received support only in some areas. In Asia, for example, the profusion of smart cellular phones and PDAs has caused the demand for IP addresses to outstrip the limited supply provided by IPv4, t...

We present Neumann-Neumann domain decomposition preconditioners for the solution of elliptic linear quadratic optimal control problems. The preconditioner is applied to the optimality system. A Schur complement formulation is derived that reformulates the original optimality system as a system in the state and adjoint variables restricted to the subdomain boundaries. The application of the Schu...

In the transport layer of the TCP/IP protocol suite, both TCP and UDP use internet checksum to protect headers and data. Internet checksum uses 1’s complement arithmetic to detect errors in the content delivered by the data-link layer. Both research and experience have shown that there are a wide variety of error sources which can not be detected by this lower layer. The error detecting perform...

We deal with the problem of preserving various versions of completeness in (< κ)–support iterations of forcing notions, generalizing the case “S–complete proper is preserved by CS iterations for a stationary costationary S ⊆ ω1”. We give applications to Uniformization and the Whitehead problem. In particular, for a strongly inaccessible cardinal κ and a stationary set S ⊆ κ with fat complement ...