SRI International

About: SRI International is a nonprofit organization based out in Menlo Park, California, United States. It is known for research contribution in the topics: Ionosphere & Laser. The organization has 7222 authors who have published 13102 publications receiving 660724 citations. The organization is also known as: Stanford Research Institute & SRI.

Model checking invariant security properties in OpenFlow

Abstract: The OpenFlow (OF) switching specification represents an innovative and open standard for enabling the dynamic programming of flow control policies in production networks. Unfortunately, thus far researchers have paid little attention to the development of methods for verifying that dynamic flow policies inserted within an OpenFlow network do not violate the network's underlying security policy. We introduce Flover, a model checking system which verifies that the aggregate of flow policies instantiated within an OpenFlow network does not violate the network's security policy. We have implemented Flover using the Yices SMT solver, which we then integrated into NOX, a popular OpenFlow network controller. Flover provides NOX a formal validation of the OpenFlow network's security posture.

Preparing Teachers to Design Sequences of Instruction in Earth Systems Science: A Comparison of Three Professional Development Programs

Abstract: This research study examined whether and how professional development can help teachers design sequences of instruction that lead to improved science learning. The efficacy of three professional development programs and a control condition was compared in a cluster randomized trial involving 53 middle school science teachers from a single school district. The four conditions varied along two dimensions: (a) the extent to which the programs guided teachers’ selection of curriculum materials and (b) whether or not teachers received explicit instruction in models of teaching associated with particular methods for designing instruction. Results indicated that the two programs most effective at improving students’ science learning were the ones in which teachers received explicit instruction in models of teaching.

n , l distributions in A q + + H electron-capture collisions

Abstract: The classical-trajectory Monte Carlo method has been used to determine product-state distributions in ${A}^{q+}+\mathrm{H}\ensuremath{\rightarrow}{A}^{(q\ensuremath{-}1)+}(\mathrm{nl})+{\mathrm{H}}^{+}$ electron-capture collisions at energies 50 and 100 keV/amu for fully stripped ions in charge states $q=1 \mathrm{to} 20$. In the energy region studied, the electron-capture products are found to populate predominately principal quantum numbers around ${n}_{m}\ensuremath{\approx}{q}^{\frac{3}{4}}$. Such behavior implies the captured electron tries to preserve both its original orbital energy and dimensions after the electron-capture collision. The orbital-angular-momentum quantum numbers $l$ are more highly peaked than statistical to large $l$ values for $nl{n}_{m}$, while they are found to maximize around $l\ensuremath{\approx}{q}^{\frac{3}{4}}$ for $ng{n}_{m}$.