1,983 research outputs found
On Energy Reduction and Green Networking Enhancement due to In-Network Caching
In-network caching in information centric networking
(ICN) is considered as a promising approach to reducing
energy consumption of an entire network. However, it is also considered as an energy consuming technique. These contradictory claims lead to one research question: Does caching really reduce the energy consumption of the entire network? To answer the question, we formulate an ICN network as an optimization problem with a realistic energy consumption model for an ICN router. By solving the formulation assuming that ICN forwarding software currently under development is used as a forwarding engine of an ICN router, we reveal that in-network
caching alone does not reduce much energy but it enhances a currently developed green networking technique even though the forwarding engine is not fully optimized
On Energy Reduction and Green Networking Enhancement due to In-Network Caching
In-network caching in information centric networking
(ICN) is considered as a promising approach to reducing
energy consumption of an entire network. However, it is also considered as an energy consuming technique. These contradictory claims lead to one research question: Does caching really reduce the energy consumption of the entire network? To answer the question, we formulate an ICN network as an optimization problem with a realistic energy consumption model for an ICN router. By solving the formulation assuming that ICN forwarding software currently under development is used as a forwarding engine of an ICN router, we reveal that in-network
caching alone does not reduce much energy but it enhances a currently developed green networking technique even though the forwarding engine is not fully optimized
Power Consumption Model of NDN-Based Multicore Software Router Based on Detailed Protocol Analysis
Named data networking (NDN) has received considerable attention recently, mainly due to its built-in caching, which is expected to enable widespread and transparent operator-controlled caching. One of the important research challenges is to reduce the amount of power consumed by NDN networks as it has been shown that NDN's name prefix matching and caching are power-hungry. As a first step to achieving power-efficient NDN networks, in this paper, we develop a power consumption model of a multicore software NDN router. By applying this model to analyze how caching reduces power, we report that caching can reduce power consumption of an NDN network if the power consumption of routers is in proportion to their load and the computation of caching is as light as that of forwarding
Producer Anonymity based on Onion Routing in Named Data Networking
Named Data Networking (NDN) is one of promising next generation Internet architectures that aim to realize efficient content distribution. However, in terms of producer anonymity, NDN has a serious problem that adversaries can easily learn who publishes what content due to its feature that content is inherently tied to the producer by the content name and the signature. In this paper, we first define producer anonymity rigorously in terms of content-producer unlinkability, and then design a system to achieve it. Our design is based on hidden service, which is an onion routing-based system in IP, however, we improve it to take full advantage of NDN. We demonstrate that our system provides a level of anonymity comparable to hidden service with lower overhead through analysis and experiment
New Supporting Evidence for the Overdensity of Galaxies around the Radio-Loud Quasar SDSS J0836+0054 at z =5.8
Recently, Zheng et al. (2005) found evidence for an overdensity of galaxies
around a radio-loud quasar, SDSS J0836+0054, at z=5.8 (a five arcmin
region). We have examined our deep optical imaging data (B, V, r', i', z', and
NB816) taken with the Suprime-Cam on the Subaru Telescope. The NB816
narrow-band filter (lambda_c = 815 nm and nm) is suitable
for searching for Ly emitters at . We have found a new
strong Ly emitter at close to object B identified by
Zheng et al. Further, the non detection of the nine objects selected by Zheng
et al. (2005) in our B, V, and r' images provides supporting evidence that they
are high-z objects.Comment: 5 pages, 1 figure, accepted for PAS
Strong Emission-Line Galaxies at Low Redshift in the Field around the Quasar SDSSp J104433.04-012502.2
We discuss observational properties of strong emission-line galaxies at low
redshift found by our deep imaging survey for high-redshift Ly alpha emitters.
In our surveys, we used the narrowband filter, NB816 (lambda_center=8150A with
FWHM = 120A), and the intermediate-band filter, IA827 (lambda_center = 8270A
with FWHM = 340A). In this survey, 62 NB816-excess (> 0.9 mag) and 21
IA827-excess (> 0.8 mag) objects were found. Among them, we found 20
NB816-excess and 4 IA827-excess Ly alpha emitter candidates. Therefore, it
turns out that 42 NB816-excess and 17 IA827-excess objects are strong
emission-line objects at lower redshift. Since 4 objects in the two low-z
samples are common, the total number of strong low-z emitters is 55. Applying
our photometric redshift technique, we identify 7 H alpha emitters at z~0.24,
20 H beta-[OIII] ones at z~0.65, and 11 [OII] ones at z~1.19. However, we
cannot determine reliable photometric redshifts of the remaining 17 emitters.
The distributions of their rest frame equivalent widths are consistently
understood with recent studies of galaxy evolution from z~1 to z~0.Comment: 28 pages, 8 figures, PASJ, Vol. 58, No. 1, in pres
Doping dependence of the exchange energies in bilayer manganites: Role of orbital degrees of freedom
Recently, an intriguing doping dependence of the exchange energies in the
bilayer manganites has been observed in the neutron
scattering experiments. The intra-layer exchange only weakly changed with
doping while the inter-layer one drastically decreased. Here we propose a
theory which accounts for these experimental findings. We argue, that the
observed striking doping dependence of the exchange energies can be attributed
to the evaluation of the orbital level splitting with doping. The latter is
handled by the interplay between Jahn-Teller effect (supporting an axial
orbital) and the orbital anisotropy of the electronic band in the bilayer
structure (promoting an in-plane orbital), which is monitored by the Coulomb
repulsion. The presented theory, while being a mean-field type, describes well
the experimental data and also gives the estimates of the several interesting
energy scales involved in the problem.Comment: Added references, corrected typos. To appear in Phys. Rev.
Weak-Coupling Theory for Multiband Superconductivity Induced by Jahn-Teller Phonons
Emergence of superconductivity in a two-band system coupled with breathing
and Jahn-Teller phonons is discussed in a weak-coupling limit. With the use of
a standard quantum mechanical procedure, the phonon-mediated attraction is
derived. From the analysis of the model including such attraction, a BCS-like
formula for a superconducting transition temperature is obtained.
When only the breathing phonon is considered, is the same as that
of the one-band model. On the other hand, when Jahn-Teller phonons are active,
is significantly enhanced by the interband attraction even within
the weak-coupling limit. Relevance of the present result to actual materials
such as iron pnictides is briefly commented.Comment: 4 pages, 3 figures
A deformed analogue of Onsager's symmetry in the XXZ open spin chain
The XXZ open spin chain with general integrable boundary conditions is shown
to possess a q-deformed analogue of the Onsager's algebra as fundamental
non-abelian symmetry which ensures the integrability of the model. This
symmetry implies the existence of a finite set of independent mutually
commuting nonlocal operators which form an abelian subalgebra. The transfer
matrix and local conserved quantities, for instance the Hamiltonian, are
expressed in terms of these nonlocal operators. It follows that Onsager's
original approach of the planar Ising model can be extended to the XXZ open
spin chain.Comment: 12 pages; LaTeX file with amssymb; v2: typos corrected,
clarifications in the text; v3: minor changes in references, version to
appear in JSTA
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