The non-modal transient properties of the Eady baroclinic model with a simple heating parameterization are examined. The time-dependent non-modal behavior of the moist baroclinic model is investigated by calculating the energy amplification of optimal perturbations for relevant time-scales and by calculating the energy evolution of random initial conditions. Enhanced non-modal growth on time-sc...

We combine ideas from relation-based data management with class hierarchies to obtain Hierarchical Knowledge Bases, which have greater expressive power while maintaining the beneets of predictable and eecient information processing. We then consider the problem of reasoning with certain limited forms of disjunctive information. We show that hierarchical knowledge bases can be used for eecient a...

V 2 A + C 2 s + V ∆t/∆x < 1 is satisfied, where VA is the Alfvén wave speed, Cs is the sound wave speed, and V is the flow speed. Unconditional stability for sound and Alfvén waves with arbitrary time step ∆t is achieved by adding a semi-implicit term to the momentum equation. However, the flow CFL condition V∆t/∆x <must still be satisfied. The resistivity and viscosity are advanced implicitly ...

The ‘Alfvén Paradox’ is that as resistivity decreases, the discrete eigenmodes do not converge to the generalized eigenmodes of the ideal Alfvén continuum. To resolve the paradox, the -pseudospectrum of the RMHD operator is considered. It is proven that for any , the pseudospectrum contains the Alfvén continuum for sufficiently small resistivity. Formal − pseudoeigenmodes are constructed using ...

We study the asymptotic behavior of the solution of a model equation for BoseEinstein condensation, in the case where the trapping potential varies randomly in time. The model is the so called Gross-Pitaevskii equation, with a quadratic potential with white noise fluctuations in time whose amplitude ε tends to zero. The initial condition of the solution is a standing wave solution of the unpert...

This paper explores the distribution of Free Choice Items (FCI) and Negative Polarity Items (NPI) in Malagasy. Both FCIs and NPIs in Malagasy are syntactically complex: they are expressed by disjunctions of wh-words. It is shown that this morphosyntactic structure directly reflects their semantics. In other words, FCIs and NPIs are semantically as well as syntactically disjunctive. Moreover, th...

Adaptive controllers are used in systems where one or more parameters are unknown. Such controllers are designed to stabilize the system using an estimate for the unknown parameters that is adapted automatically as part of the stabilization. One drawback in adaptive control design is the possibility that the closed-loop limit system is not stable. The worst situation is the existence of a desta...

This paper analyzes the chaotic characteristics of irregular systems using both wave theory and ray theory. In ray theory, we visualize the chaotic properties of the ray propagation trajectories in a chaotic wave field. We found that the trajectory of the billiard problem with a stadium boundary condition has the same sensitivities to the initial conditions as does the mapping process on a logi...