52 research outputs found
Tachyonic Teleparallel Dark Energy
Teleparallel gravity is an equivalent formulation of general relativity in
which instead of the Ricci scalar , one uses the torsion scalar for the
Lagrangian density. Recently teleparallel dark energy has been proposed by Geng
et al. in (Geng et al., 2011). They have added quintessence scalar field,
allowing also a non-minimal coupling with gravity in the Lagrangian of
teleparallel gravity and found that such a non-minimally coupled quintessence
theory has a richer structure than the same one in the frame work of general
relativity. In the present work we are interested in tachyonic teleparallel
dark energy in which scalar field is responsible for dark energy in the frame
work of torsion gravity. We find that such a non-minimally coupled tachyon
gravity can realize the crossing of the phantom divide line for the effective
equation of state. Using the numerical calculations we display such a behavior
of the model explicitly.Comment: 12 pages, 4 figures, accepted for publication in Astrophysics and
Space Scienc
Kuksa*: Self-Adaptive Microservices in Automotive Systems
In pervasive dynamic environments, vehicles connect to other objects to send
operational data and receive updates so that vehicular applications can provide
services to users on demand. Automotive systems should be self-adaptive,
thereby they can make real-time decisions based on changing operating
conditions. Emerging modern solutions, such as microservices could improve
self-adaptation capabilities and ensure higher levels of quality performance in
many domains. We employed a real-world automotive platform called Eclipse Kuksa
to propose a framework based on microservices architecture to enhance the
self-adaptation capabilities of automotive systems for runtime data analysis.
To evaluate the designed solution, we conducted an experiment in an automotive
laboratory setting where our solution was implemented as a microservice-based
adaptation engine and integrated with other Eclipse Kuksa components. The
results of our study indicate the importance of design trade-offs for quality
requirements' satisfaction levels of each microservices and the whole system
for the optimal performance of an adaptive system at runtime
Phantom Divide Crossing with General Non-minimal Kinetic Coupling
We propose a model of dark energy consists of a single scalar field with a
general non-minimal kinetic couplings to itself and to the curvature. We study
the cosmological dynamics of the equation of state in this setup. The coupling
terms have the form and
where
and are coupling parameters and their dimensions depend on the type
of function . We obtain the conditions required for phantom divide
crossing and show numerically that a cosmological model with general
non-minimal derivative coupling to the scalar and Ricci curvatures can realize
such a crossing.Comment: 12 pages, 4 figures. Accepted for publication in Gen. Rel. Grav.
arXiv admin note: substantial text overlap with arXiv:1105.4967,
arXiv:1201.1627, and with arXiv:astro-ph/0610092 by other author
Gravity and Electromagnetism with -type Coupling and Magnetic Monopole Solutions
We investigate -type coupling of electromagnetic fields to
gravity. After we derive field equations by a first order variational principle
from the Lagrangian formulation of the non-minimally coupled theory, we look
for static, spherically symmetric, magnetic monopole solutions. We point out
that the solutions can provide possible geometries which may explain the
flatness of the observed rotation curves of galaxies.Comment: 10 page
Energy Conditions in Modified Gravity with Non-minimal Coupling to Matter
In this paper we study a model of modified gravity with non-minimal coupling
between a general function of the Gauss-Bonnet invariant, , and matter
Lagrangian from the point of view of the energy conditions. Such model has been
introduced in Ref. [21] for description of early inflation and late-time cosmic
acceleration. We present the suitable energy conditions for the above mentioned
model and then, we use the estimated values of the Hubble, deceleration and
jerk parameters to apply the obtained energy conditions to the specific class
of modified Gauss-Bonnet models.Comment: 12 pages, no figur, Accepted for publication in Astrophysics and
Space Scienc
Phantom Behavior Bounce with Tachyon and Non-minimal Derivative Coupling
The bouncing cosmology provides a successful solution of the cosmological
singularity problem. In this paper, we study the bouncing behavior of a single
scalar field model with tachyon field non-minimally coupled to itself, its
derivative and to the curvature. By utilizing the numerical calculations we
will show that the bouncing solution can appear in the universe dominated by
such a quintom matter with equation of state crossing the phantom divide line.
We also investigate the classical stability of our model using the phase
velocity of the homogeneous perturbations of the tachyon scalar field.Comment: 15 pages, 8 figures, Accepted for publication in JCAP. arXiv admin
note: substantial text overlap with arXiv:1105.496
Heterogeneous 2.5D integration on through silicon interposer
© 2015 AIP Publishing LLC. Driven by the need to reduce the power consumption of mobile devices, and servers/data centers, and yet continue to deliver improved performance and experience by the end consumer of digital data, the semiconductor industry is looking for new technologies for manufacturing integrated circuits (ICs). In this quest, power consumed in transferring data over copper interconnects is a sizeable portion that needs to be addressed now and continuing over the next few decades. 2.5D Through-Si-Interposer (TSI) is a strong candidate to deliver improved performance while consuming lower power than in previous generations of servers/data centers and mobile devices. These low-power/high-performance advantages are realized through achievement of high interconnect densities on the TSI (higher than ever seen on Printed Circuit Boards (PCBs) or organic substrates), and enabling heterogeneous integration on the TSI platform where individual ICs are assembled at close proximity
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