Dynamical Systems; Proceedings of an IIASA Workshop, Sopron, Hungary, September 9-13, 1985

The investigation of special topics in systems dynamics -- uncertain dynamic processes, viability theory, nonlinear dynamics in models for biomathematics, inverse problems in control systems theory -- has become a major issue at the System and Decision Sciences Research Program of IIASA. The above topics actually reflect two different perspectives in the investigation of dynamic processes. The first, motivated by control theory, is concerned with the properties of dynamic systems that are stable under variations in the systems' parameters. This allows us to specify classes of dynamic systems for which it is possible to construct and control a whole "tube" of trajectories assigned to a system with uncertain parameters and to resolve some inverse problems of control theory within numerically stable solution schemes. The second perspective is to investigate generic properties of dynamic systems that are due to nonlinearity (as bifurcations theory, chaotic behavior, stability properties, and related problems in the qualitative theory of differential systems). Special stress is given to the applications of nonlinear dynamic systems theory to biomathematics and ecology. The proceedings of a workshop on the "Mathematics of Dynamic Processes", dealing with these topics is presented in this volume

Boundary stabilization of focusing NLKG near unstable equilibria: radial case

We investigate the stability and stabilization of the cubic focusing Klein-Gordon equation around static solutions on the closed ball in $\mathbb{R}^3$. First we show that the system is linearly unstable near the static solution $u\equiv 1$ for any dissipative boundary condition $u_t+ au_{\nu}=0, a\in (0, 1)$. Then by means of boundary controls (both open-loop and closed-loop) we stabilize the system around this equilibrium exponentially with rate less than $\frac{\sqrt{2}}{2L} \log{\frac{1+a}{1-a}}$, which is sharp, provided that the radius of the ball $L$ satisfies $L\neq \tan L$

Aeronautical engineering: A continuing bibliography with indexes (supplement 271)

This bibliography lists 666 reports, articles, and other documents introduced into the NASA scientific and technical information system in October, 1991. Subject coverage includes design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Analysis of Water Waves in the Presence of Geometry and Damping

The evolution of waves on the surface of a body of water (or another approximately inviscid liquid) is governed by the free-surface Euler equations; that is, the incompressible Euler equations coupled with a kinematic and a dynamic boundary condition on the free surface. We assume that the flow has zero vorticity in the bulk of the fluid domain and so consider the irrotational free-surface Euler equations (the water waves system). Two major themes are present in our study of the water waves system. The first is the consideration of flows in the presence of substantial geometric features. The second theme is the consideration of the effects of damping, which is an essential tool in the numerical study of water waves. In both contexts, our objective is to consider the local-in-time well-posedness of the water waves system and to study the lifespan of solutions (i.e., the timescales on which solutions to the water waves system persist).Doctor of Philosoph