13,211 research outputs found

### Multirole logic and multiparty channels

We identify multirole logic as a new form of logic in which conjunction/disjunction is interpreted as an ultrafilter on the power set of some underlying set (of roles), and the notion of negation is generalized to endomorphisms on this underlying set. In this talk, we present linear multirole logic (LMRL) as a natural generalization of classical linear logic (CLL). Among various meta-properties established for LMRL, we obtain one named multiparty cut-elimination stating that every cut involving one or more sequents (as a generalization of a binary cut involving exactly two sequents) can be eliminated, thus extending the celebrated result of cut-elimination by Gentzen. An immediate application of LMRL can be found in a formulation of session types for channels that support multiparty communication in distributed programming. Guided by LMRL, we give an interesting interpretation to linear multiplicative conjunction/disjunction as session type constructors that encompasses certain seemingly contradictory ones found in the literature

### Retrieving the Size of Deep-subwavelength Objects via Tunable Optical Spin-Orbit Coupling

We propose a scheme to retrieve the size parameters of a nano-particle on a
glass substrate at a scale much smaller than the wavelength. This is achieved
by illuminating the particle using two plane waves to create rich and
non-trivial local polarization distributions, and observing the far-field
scattering pattern into the substrate. A simple dipole model which exploits
tunneling effect of evanescent field into regions beyond the critical angle, as
well as directional scattering due to spin-orbit coupling is developed, to
relate the particle's shape, size and position to the far-field scattering with
remarkable sensitivity. Our method brings about a far-field super-resolution
imaging scheme based on the interaction of vectorial light with nanoparticles

### Non-negligible magnetic dipole scattering from metallic nanowire for ultrasensitive deflection sensing

It is generally believed that when a single metallic nanowire is sufficiently
small, it scatters like a point electric dipole. We show theoretically when a
metallic nanowire is placed inside specially designed beams, the non-negligible
magnetic dipole contribution along with the electric dipole resonance can lead
to unidirectional scattering in the far-field, fulfilling Kerker's condition.
Remarkably, this far-field unidirectional scattering encodes information that
is highly dependent on the nanowire's deflection at a scale much smaller than
the wavelength. The special role of small but non-negligible magnetic response
and plasmonic resonance are highlighted for this extreme sensitivity as
compared with the dielectric counterpart. Effects such as scattering efficiency
and shape of the nanowire's cross section are also discussed.Comment: 5 pages, 3 figures. Comments are welcom

### Dynamical Properties of Multi-Armed Global Spirals in Rayleigh-Benard Convection

Explicit formulas for the rotation frequency and the long-wavenumber
diffusion coefficients of global spirals with $m$ arms in Rayleigh-Benard
convection are obtained. Global spirals and parallel rolls share exactly the
same Eckhaus, zigzag and skewed-varicose instability boundaries. Global spirals
seem not to have a characteristic frequency $\omega_m$ or a typical size $R_m$,
but their product $\omega_m R_m$ is a constant under given experimental
conditions. The ratio $R_i/R_j$ of the radii of any two dislocations ($R_i$,
$R_j$) inside a multi-armed spiral is also predicted to be constant. Some of
these results have been tested by our numerical work.Comment: To appear in Phys. Rev. E as Rapid Communication

### Photon-assisted electron transmission resonance through a quantum well with spin-orbit coupling

Using the effective-mass approximation and Floquet theory, we study the
electron transmission over a quantum well in semiconductor heterostructures
with Dresselhaus spin-orbit coupling and an applied oscillation field. It is
demonstrated by the numerical evaluations that Dresselhaus spin-orbit coupling
eliminates the spin degeneracy and leads to the splitting of asymmetric
Fano-type resonance peaks in the conductivity. In turn, the splitting of
Fano-type resonance induces the spin- polarization-dependent electron-current.
The location and line shape of Fano-type resonance can be controlled by
adjusting the oscillation frequency and the amplitude of external field as
well. These interesting features may be a very useful basis for devising
tunable spin filters.Comment: 10pages,4figure

### Use of Devolved Controllers in Data Center Networks

In a data center network, for example, it is quite often to use controllers
to manage resources in a centralized man- ner. Centralized control, however,
imposes a scalability problem. In this paper, we investigate the use of
multiple independent controllers instead of a single omniscient controller to
manage resources. Each controller looks after a portion of the network only,
but they together cover the whole network. This therefore solves the
scalability problem. We use flow allocation as an example to see how this
approach can manage the bandwidth use in a distributed manner. The focus is on
how to assign components of a network to the controllers so that (1) each
controller only need to look after a small part of the network but (2) there is
at least one controller that can answer any request. We outline a way to
configure the controllers to fulfill these requirements as a proof that the use
of devolved controllers is possible. We also discuss several issues related to
such implementation.Comment: Appears in INFOCOM 2011 Cloud Computing Worksho

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