Strong, fast pulses, called ‘‘bang–bang’’ controls can be used to eliminate the effects of system-environment interactions. This method for preventing errors in quantum information processors is treated here in a geometric setting which leads to an intuitive perspective. Using this geometric description, we clarify the notion of group symmetrization as an averaging technique, provide a geometri...

In this paper we use an optimal control approach to analyze time dependent enzyme concentrations that minimize the transition time of a metabolic pathway while respecting the natural constraints imposed by a limited biosynthetical capacity. Our main result states that, under appropriate assumptions, at each time instant all the available enzyme production capacity is allocated to a single react...

A principal technical result of this paper is that the onedimensional heat equation with boundary control is exactly null-controllable with control restricted to an arbitrary set E ⊂ [0, T ] of positive measure. A general abstract argument is presented to show that this implies the ‘bangbang’ property for time-optimal controls — i.e., such a control can take only extreme values of (the hull of)...

In this article, we propose a new paradigm of control, called a maximum-hands-off control. A hands-off control is defined as a control that has a much shorter support than the horizon length. The maximum-hands-off control is the minimum-support (or sparsest) control among all admissible controls. We first prove that a solution to an L-optimal control problem gives a maximum-handsoff control, an...

A teoria do Big Bang corresponde ao modelo explicativo início Universo a partir de um ponto (singularidade) elevada densidade e temperatura que começa expandir- se, criando-se o espaço-tempo. Sendo seguido pelo período inflação cósmica, dominado pela radiação outro matéria (principalmente escura) até momento atual, por uma energia escura, permite explicar história nosso observável. O é bem test...

OBJECTIVES The main aim has been to examine psychometric properties of STOP-Bang (snoring, tiredness, observed apnea, high blood pressure, body mass index (BMI), age, neck circumference, male gender) scoring model (Serbian translation), an obstructive sleep apnea (OSA) screening tool, in a sample of commercial drivers. MATERIAL AND METHODS After formal translation, validation was performed on...

Materials and methods In a prospective cohort design, 158 women answered a version of the STOP-Bang questionnaire adapted for pregnant women using age cutoff at 35 yrs. and excluding male gender (STOP-Ban); risk for sleep apnea was considered present when score>2. Obstetric history and physical examination were obtained. Both gestational and pre-gestational diabetes were considered for the anal...

This paper gives sufficient conditions for a class of bang-bang extremals with multiple switches to be locally optimal in the strong topology. The conditions are the natural generalizations of the ones considered in [5, 14] and [16]. We require both the strict bang-bang Legendre condition, and the second order conditions for the finite dimensional problem obtained by moving the switching times ...

This paper deals with the optimal control problem that arise when a hydraulic system with fixed-head hydroplants is considered. In the frame of a deregulated electricity market the resulting Hamiltonian for such systems is linear in the control variable and results in an optimal singular/bang-bang control policy. To avoid difficulties associated with the computation of optimal singular/bang-ban...