Stability results are given for a class of feedback systems arising from the regulation of time-varying discrete-time systems using optimal infinite-horizon and moving-horizon feedback laws. The class is characterized by joint constraints on the state and the control, a general nonlinear cost function and nonlinear equations of motion possessing two special properties. It is shown that weak con...

We study the horizon absorption of gravitational waves in coalescing, circularized, nonspinning blackhole binaries. The horizon-absorbed fluxes of a binary with a large mass ratio (q 1⁄4 1000) obtained by numerical perturbative simulations are compared with an analytical, effective-one-body (EOB) resummed expression recently proposed. The perturbative method employs an analytical, linear in the...

We study anti-de Sitter black holes and evaluate different thermodynamic quantities in the EinsteinGauss-Bonnet and the general R2 gravity theories. We examine the possibility of Hawking-Page type thermal phase transitions between AdS black hole and thermal anti-de Sitter space in such theories. In Einstein theory with a possible cosmological term, one observes a Hawking-Page phase transition o...

We define what is a replacement policy for a system that fails randomly in time and its main characteristics. There are several parameters that drive the structure of the optimal policy. We provide a detailed discussion of the time horizon, objective functions, and failure time distributions as part of any replacement policy. 1 Definitions and main characteristics Our daily lives involve the ob...

In this paper we consider an agent on a financial market who can trade with an uncertain time horizon by investing in risky stocks and a risk-free bond. He aims at maximizing the utility he draws from his final wealth measured by some utility function. We obtain a sufficient and necessary condition for the optimality, which gives an explicit expression for the optimal strategies as solutions of...

OBJECTIVES To examine the costs and benefits associated with long-term etanercept (ETN) treatment in patients with severe ankylosing spondylitis (AS) in the UK in accordance with the BSR guidelines. METHODS A mathematical model was constructed to estimate the costs and benefits associated with ETN plus non-steroidal anti-inflammatory drugs (NSAIDs) compared with NSAIDs alone. Individual patie...