147 research outputs found
Application of Market Models to Network Equilibrium Problems
We present a general two-side market model with divisible commodities and
price functions of participants. A general existence result on unbounded sets
is obtained from its variational inequality re-formulation. We describe an
extension of the network flow equilibrium problem with elastic demands and a
new equilibrium type model for resource allocation problems in wireless
communication networks, which appear to be particular cases of the general
market model. This enables us to obtain new existence results for these models
as some adjustments of that for the market model. Under certain additional
conditions the general market model can be reduced to a decomposable
optimization problem where the goal function is the sum of two functions and
one of them is convex separable, whereas the feasible set is the corresponding
Cartesian product. We discuss some versions of the partial linearization
method, which can be applied to these network equilibrium problems.Comment: 18 pages, 3 table
Implementation of Fault-tolerant Quantum Logic Gates via Optimal Control
The implementation of fault-tolerant quantum gates on encoded logic qubits is
considered. It is shown that transversal implementation of logic gates based on
simple geometric control ideas is problematic for realistic physical systems
suffering from imperfections such as qubit inhomogeneity or uncontrollable
interactions between qubits. However, this problem can be overcome by
formulating the task as an optimal control problem and designing efficient
algorithms to solve it. In particular, we can find solutions that implement all
of the elementary logic gates in a fixed amount of time with limited control
resources for the five-qubit stabilizer code. Most importantly, logic gates
that are extremely difficult to implement using conventional techniques even
for ideal systems, such as the T-gate for the five-qubit stabilizer code, do
not appear to pose a problem for optimal control.Comment: 18 pages, ioptex, many figure
HUMAN GRANULOCYTOTROPIC ANAPLASMOSIS
Natural focal tick-borne infections are widespread in the world and are characterized by a great etiologic diversity. Human granulocytotropic anaplasmosis (HGA), also transmitted by the bite of ticks became relevant in the last century of detection not only in animals but also in humans. The review provides an overview of the incidence of HGA in Russia and in the world, the prevalence of the habitat of mites, the diversity of reservoirs and sources of infection, mechanisms and pathways of transmission of the pathogen Anaplasma phagocytophilum and its biological features. The links and stages of the disease pathogenesis are considered in detail. Scientific data on the clinical course of the disease, the frequency and diversity of various symptoms of the disease, the issues of laboratory and differential diagnosis of anaplasmosis and its place in the nosological structure in patients with fever of unknown origin are discussed. At the same time, choosing a method of laboratory diagnostics it is necessary to take into account that molecular-genetic method (polymerase chain reaction PCR-diagnosis) allows to confirm the diagnosis quickly, while serological methods of research in a greater degree - to put a retrospective diagnosis. The article presents current data on the treatment of disease and methods of HGA prevention and also presents the results of the authors’ own observations based on the survey of 63 patients. The analysis of Moscow residents treatment about sucking mites is carried out and summarized the incidence of infections transmitted by ixode mites. For the diagnosis of HGA and other tick-borne fever used a technique called polymerase chain reaction. It has been revealed that in Moscow, lime borreliosis occupies a leading place among mites associated with infections 60%, and the share of granulocytic anaplasmosis of a person is only 5% of patients. However, the study of ticks for the presence of HGA pathogens and other natural focal tick infections is carried out in insufficient volume (less than 30%), which should be considered in clinical and laboratory differential diagnosis, as well as preventive measures
On a network equilibrium problem with mixed demand
© Springer International Publishing Switzerland 2016.In the present paper, we formulate the network equilibrium problem with mixed demand containing the fixed and variable components. We present the equilibrium conditions and the conditions for existence of solution of this problem. In addition, we show that the network equilibrium problem with mixed demand generalizes the network equilibrium problems with fixed demand and elastic demand and establish the connection with the auction equilibrium problem. Preliminary computational experiments are also presented
Optimizing entangling quantum gates for physical systems
Optimal control theory is a versatile tool that presents a route to
significantly improving figures of merit for quantum information tasks. We
combine it here with the geometric theory for local equivalence classes of
two-qubit operations to derive an optimization algorithm that determines the
best entangling two-qubit gate for a given physical setting. We demonstrate the
power of this approach for trapped polar molecules and neutral atoms.Comment: extended version; Phys. Rev. A (2011
Photon storage in Lambda-type optically dense atomic media. I. Cavity model
In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)], we
used a universal physical picture to optimize and demonstrate equivalence
between a wide range of techniques for storage and retrieval of photon wave
packets in Lambda-type atomic media in free space, including the adiabatic
reduction of the photon group velocity, pulse-propagation control via
off-resonant Raman techniques, and photon-echo-based techniques. In the present
paper, we perform the same analysis for the cavity model. In particular, we
show that the retrieval efficiency is equal to C/(1+C) independent of the
retrieval technique, where C is the cooperativity parameter. We also derive the
optimal strategy for storage and, in particular, demonstrate that at any
detuning one can store, with the optimal efficiency of C/(1+C), any smooth
input mode satisfying T C gamma >> 1 and a certain class of resonant input
modes satisfying T C gamma ~ 1, where T is the duration of the input mode and 2
gamma is the transition linewidth. In the two subsequent papers of the series,
we present the full analysis of the free-space model and discuss the effects of
inhomogeneous broadening on photon storage.Comment: 16 pages, 2 figures. V2: significant changes in presentation, new
references, higher resolution of figure
Photon storage in Lambda-type optically dense atomic media. II. Free-space model
In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)], we
presented a universal physical picture for describing a wide range of
techniques for storage and retrieval of photon wave packets in Lambda-type
atomic media in free space, including the adiabatic reduction of the photon
group velocity, pulse-propagation control via off-resonant Raman techniques,
and photon-echo based techniques. This universal picture produced an optimal
control strategy for photon storage and retrieval applicable to all approaches
and yielded identical maximum efficiencies for all of them. In the present
paper, we present the full details of this analysis as well some of its
extensions, including the discussion of the effects of non-degeneracy of the
two lower levels of the Lambda system. The analysis in the present paper is
based on the intuition obtained from the study of photon storage in the cavity
model in the preceding paper [Gorshkov et al., Phys. Rev. A 76, 033804 (2007)].Comment: 26 pages, 8 figures. V2: significant changes in presentation, new
references, higher resolution of figure
A Tentative Modeling Study of the Effect of Wall Reactions on Oxidation Phenomena
This paper gives details of a tentative modeling study that investigates the
inhibiting effect of internal reactor walls treated with acid..
Photon storage in Lambda-type optically dense atomic media. IV. Optimal control using gradient ascent
We use the numerical gradient ascent method from optimal control theory to
extend efficient photon storage in Lambda-type media to previously inaccessible
regimes and to provide simple intuitive explanations for our optimization
techniques. In particular, by using gradient ascent to shape classical control
pulses used to mediate photon storage, we open up the possibility of high
efficiency photon storage in the non-adiabatic limit, in which analytical
solutions to the equations of motion do not exist. This control shaping
technique enables an order-of-magnitude increase in the bandwidth of the
memory. We also demonstrate that the often discussed connection between time
reversal and optimality in photon storage follows naturally from gradient
ascent. Finally, we discuss the optimization of controlled reversible
inhomogeneous broadening.Comment: 16 pages, 7 figures. V2: As published in Phys. Rev. A. Moved most of
the math to appendices or removed altogether. Switched order of Sections II
and III. Shortened abstract. Added reference
Assessment of the effectiveness of the use of caps for the treatment of temporomandibular joint dysfunction
The purpose of the study was to evaluate the effectiveness of using a mouth guard on the upper jaw to restore the occlusal relationship of the dentition in patients with defects in the dentition and symptoms of TMJ dysfunction.Цель исследования - оценить эффективность применения каппы на верхнюю челюсть для восстановления окклюзионных взаимоотношений зубных рядов у пациентов с дефектами зубных рядов и симптомами дисфункции ВНЧС
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