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.

Lidar: A new atmospheric probe

Abstract: Pulsed-light techniques of probing the atmosphere have been greatly extended by employing lasers as energy sources in instruments called ‘lidars.’ Because of the nature of laser energy and the manner in which it is used in current and proposed systems, lidar is best discussed in terms of radar. Apart from the basic capabilities of lidar for detecting backscattering from atmospheric constituents, possibilities exist for more sophisticated techniques based on the wave nature of the energy. The basic capabilities of lidar, however, make it possible to observe the atmosphere with previously unknown resolution and sensitivity. Apart from providing new information about clouds, lidar has shown that the concentration of the particulate matter content of clear air is highly variable and that such variations can indicate the structure and motion of the clear atmosphere. These capabilities have applications in atmospheric and meteorological research and various operational activities.

Coupled electrodynamics in the nighttime midlatitude ionosphere

Abstract: We describe a new, self-consistent scenario in which sporadic-E doublets, height bands of upward-displaced F-layer profiles, F-region plasma depletions, and radar backscatter plumes, are all manifestations of a coupled electrodynamical response by the nighttime midlatitude ionosphere to the presence of a traveling ionospheric disturbance (TID) We show that the response consists of (1) formation of image plasma structure in the E region, (2) initiation of a Hall-current-driven polarization process by the E-region plasma structure, and (3) mapping of the polarization electric field to the F region, where it strengthens the electrical properties of the TID that initiated the E-region processes This scenario provides ready answers for several, hitherto puzzling, questions and a basis for new directions on this research topic

An operational semantics for stateflow

Abstract: We present a formal operational semantics for Stateflow, the graphical Statecharts-like language of the Matlab/Simulink tool suite that is widely used in model-based development of embedded systems. Stateflow has many tricky features but our operational treatment yields a surprisingly simple semantics for the subset that is generally recommended for industrial applications. We have validated our semantics by developing an interpreter that allows us to compare its behavior against the Matlab simulator. We have used the semantics as a foundation for developing prototype tools for formal analysis of Stateflow designs.

Monotonic semantic interpretation

Abstract: Aspects of semantic interpretation, such as quantifier scoping and reference resolution, are often realised computationally by non-monotonic operations involving loss of information and destructive manipulation of semantic representations. The paper describes how monotonic reference resolution and scoping can be carried out using a revised Quasi Logical Form (QLF) representation. Semantics for QLF are presented in which the denotations of formulas are extended monotonically as QLF expressions are resolved.