397,839 research outputs found
Task Release Control for Decision Making Queues
We consider the optimal duration allocation in a decision making queue.
Decision making tasks arrive at a given rate to a human operator. The
correctness of the decision made by human evolves as a sigmoidal function of
the duration allocated to the task. Each task in the queue loses its value
continuously. We elucidate on this trade-off and determine optimal policies for
the human operator. We show the optimal policy requires the human to drop some
tasks. We present a receding horizon optimization strategy, and compare it with
the greedy policy.Comment: 8 pages, Submitted to American Controls Conference, San Francisco,
CA, June 201
Two-loop renormalization of the Finkel'stein theory: The specific heat
We explore the two-loop renormalization of the specific heat for an
interacting disordered electron system in the case of broken time reversal
symmetry. Within the nonlinear sigma model approach we derive the two-loop
result for the anomalous dimension which controls scaling of the specific heat
with temperature. As an example, we elaborate the metal-insulator transition in
dimensions for the case of broken time reversal and spin
rotational symmetries and in the presence of Coulomb interaction. In this
situation scaling of the specific heat is determined by the anomalous dimension
of the Finkel'stein operator which is the eigen operator of the renormalization
group complementary to the eigen operator corresponding to the second moment of
the local density of states. We find that the absolute values of the anomalous
dimensions of these operators differ beyond one-loop approximation contrary to
the noninteracting case.Comment: 18 pages, elsarticle styl
Conformational and thermodynamic hallmarks of DNA operator site specificity in the copper sensitive operon repressor from Streptomyces lividans
Metal ion homeostasis in bacteria relies on metalloregulatory proteins to upregulate metal resistance genes and enable the organism to preclude metal toxicity. The copper sensitive operon repressor (CsoR) family is widely distributed in bacteria and controls the expression of copper efflux systems. CsoR operator sites consist of G-tract containing pseudopalindromes of which the mechanism of operator binding is poorly understood. Here, we use a structurally characterized CsoR from Streptomyces lividans (CsoRSl) together with three specific operator targets to reveal the salient features pertaining to the mechanism of DNA binding. We reveal that CsoRSl binds to its operator site through a 2-fold axis of symmetry centred on a conserved 5′-TAC/GTA-3′ inverted repeat. Operator recognition is stringently dependent not only on electropositive residues but also on a conserved polar glutamine residue. Thermodynamic and circular dichroic signatures of the CsoRSl-DNA interaction suggest selectivity towards the A-DNA-like topology of the G-tracts at the operator site. Such properties are enhanced on protein binding thus enabling the symmetrical binding of two CsoRSl tetramers. Finally, differential binding modes may exist in operator sites having more than one 5′-TAC/GTA-3′ inverted repeat with implications in vivo for a mechanism of modular control. © 2013 The Author(s)
A singular controllability problem with vanishing viscosity
The aim of this paper is to answer the question: Do the controls of a
vanishing viscosity approximation of the one dimensional linear wave equation
converge to a control of the conservative limit equation? Our viscous term
contains the fractional power of the Dirichlet Laplace operator and it is
multiplied by a small parameter devoted to tend to zero. Our analysis, based on
moment problems and biorthogonal sequences, enables us to evaluate the
magnitude of the controls needed for each eigenmode and to show their uniform
boundedness with respect to the vanishing parameter
A sharp estimate for the first Robin-Laplacian eigenvalue with negative boundary parameter
In this paper we prove that the ball maximizes the first eigenvalue of the
Robin Laplacian operator with negative boundary parameter, among all convex
sets of \mathbb{R}^n with prescribed perimeter. The key of the proof is a
dearrangement procedure of the first eigenfunction of the ball on the level
sets of the distance function to the boundary of the convex set, which controls
the boundary and the volume energies of the Rayleigh quotient
Survey of multi-function display and control technology
The NASA orbiter spacecraft incorporates a complex array of systems, displays and controls. The incorporation of discrete dedicated controls into a multi-function display and control system (MFDCS) offers the potential for savings in weight, power, panel space and crew training time. The technology applicable to the development of a MFDCS for orbiter application is surveyed. Technology thought to be applicable presently or in the next five years is highlighted. Areas discussed include display media, data handling and processing, controls and operator interactions and the human factors considerations which are involved in a MFDCS design. Several examples of applicable MFDCS technology are described
Anthropometric considerations for a 4-axis side-arm flight controller
A data base on multiaxis side-arm flight controls was generated. The rapid advances in fly-by-light technology, automatic stability systems, and onboard computers have combined to create flexible flight control systems which could reduce the workload imposed on the operator by complex new equipment. This side-arm flight controller combines four controls into one unit and should simplify the pilot's task. However, the use of a multiaxis side-arm flight controller without complete cockpit integration may tend to increase the pilot's workload
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