Risk analysis has been used to manage the security of systems for several decades. However, its use has been limited to offline risk computation and manual response. In contrast, we use risk computation to drive changes in an operating system’s security configuration. This allows risk management to occur in real time and reduces the window of exposure to attack. We posit that it is possible to ...

In this paper we present an analytical study of a subgrid scale turbulence model of the threedimensional magnetohydrodynamic (MHD) equations, inspired by the Navier-Stokes-α (also known as the viscous Camassa-Holm equations or the Lagrangian-averaged Navier-Stokes-α model. Specifically, we show the global well-posedness and regularity of solutions of a certain MHD-α model (which is a particular...

Thin cylindrical shell structures can show interesting bistable behaviour. If made unstressed from isotropic materials they are only stable in the initial configuration, but if made from fibre-reinforced composites they may also have a second, stable configuration. If the layup of the composite is antisymmetric, this alternative stable configuration forms a tight coil; if the layup is symmetric...

In this paper, we show that the complete set of PID controllers that stabilizes a LTI plant and achieves prescribed performance levels, can be computed from knowledge of only the frequency response (Nyquist or Bode plot) of the plant and the number of RHP poles. The result is of practical importance in many situations where transfer function or state space models are not available and a design ...

Collaborative localization is a special case for knowledge fusion where information is exchanged in order to attain improved global and local knowledge. We propose analytical as well as agent based simulation models for pedestrian dead reckoning (PDR) systems in agents collaborating to improve their location estimate by exchanging subjective position information when two agents are detected clo...

This paper deals with the construction of piecewise analytic approximate solutions for nonlinear initial value problems modeled by a system of nonlinear ordinary differential equations. In real world several biological and environmental parameters in the predator-prey model vary in time. Thus, non-autonomous systems are important to be studied. We show the effectiveness of the method for autono...

Elmore delay has been widely used to estimate the interconnect delays in the performance-driven synthesis and layout of VLSI routing topologies. For typical RLC interconnections, Elmore delay can deviate signiicantly (by up to 33% or more) from SPICE-computed delay, since it is independent of inductance. We develop an analytical delay model to incorporate inductance eeects into the delay estima...

Adaptive routing algorithms have been frequently suggested as a means of improving communication performance in multicomputers. These algorithms, unlike deterministic routing, can utilize network state information to exploit the presence of multiple paths. Adaptive routing, however, is complex and expensive. Before such schemes can be successfully incorporated in multiprocessor systems, it is n...

Discrete-event simulation of computer networks has significant scalability issues, which makes simulating large-scale networks problematic. We propose a high-level abstraction modeling network domains, interdomain links and traffic with highly scalable analytical models, which is much more efficient but slightly less accurate than node-by-node models. Thus, simulation scenarios containing sever...

Adaptive routing algorithms have been frequently suggested as a means of improving communication performance in multicomputers. These algorithms, unlike deterministic routing, can utilize network state information to exploit the presence of multiple paths. Adaptive routing, however, is complex and expensive. Before such schemes can be successfully incorporated in multiprocessor systems, it is n...