232 research outputs found
Modelling and Simulation Challenges in Internet of Things
With the rise of Internet of Things (IoT) technology, it is anticipated that large-scale sensor-based systems will permeate society, calling for novel methodologies to design, test, and operate these systems. IoT relies on networked, interconnected physical devices that often feature computational capabilities. The sheer number of these interconnected devices plays a key role in the IoT revolution. For example, Gartner research predicts that IoT will connect up to 50 to 100 billion devices by 2020. It is estimated that IoT will generate ~1.7 trillion US dollars by this time, with an approximate growth rate of 20% year over year
STUDY OF THE LEUKOCYTE MIGRATION INHIBITORY FACTOR IN HUMAN GLOMERULONEPHRITIS FROM THE ASPECT OF THE PROGNOSIS
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One click cloud orchestrator: Bringing complex applications effortlessly to the clouds
© Springer International Publishing Switzerland 2014.Infrastructure cloud systems offer basic functionalities only for managing complex virtual infrastructures. These functionalities demand low-level understanding of applications and their infrastructural needs. Recent research has identified several techniques aimed at enabling the semi-automated management and using applications that span across multiple virtual machines. Even with these efforts however, a truly flexible and end-user oriented approach is missing. This paper presents the One Click Cloud Orchestrator that not only allows higher level of automated infrastructure management than it was possible before, but it also allows end-users to focus on their computational problems instead of the complex cloud infrastructures needed for their execution. To accomplish these goals the paper reveals the novel building blocks of our new orchestrator from the components closely related to infrastructure cloud to the ways virtual infrastructures are modeled. Finally, we show our initial evaluation and study on how the orchestrator fulfills the high level requirements of end-users
Enhancing Federated Cloud Management with an Integrated Service Monitoring Approach
Cloud Computing enables the construction and the provisioning of virtualized service-based applications in a simple and cost effective outsourcing to dynamic service environments. Cloud Federations envisage a distributed, heterogeneous environment consisting of various cloud infrastructures by aggregating different IaaS provider capabilities coming from both the commercial and the academic area. In this paper, we introduce a federated cloud management solution that operates the federation through utilizing cloud-brokers for various IaaS providers. In order to enable an enhanced provider selection and inter-cloud service executions, an integrated monitoring approach is proposed which is capable of measuring the availability and reliability of the provisioned services in different providers. To this end, a minimal metric monitoring service has been designed and used together with a service monitoring solution to measure cloud performance. The transparent and cost effective operation on commercial clouds and the capability to simultaneously monitor both private and public clouds were the major design goals of this integrated cloud monitoring approach. Finally, the evaluation of our proposed solution is presented on different private IaaS systems participating in federations. © 2013 Springer Science+Business Media Dordrecht
On the Slow Roll Expansion for Brane Inflation
One possibility for identifying the inflaton in the framework of string
theory is that it is a -brane modulus. This option involves a specific,
non-canonical form of the kinetic energy -- the Dirac-Born-Infeld action. This
note investigates the applicability of the slow roll approximation in
inflationary models of this type. To this end the slow roll expansion of
Liddle, Parsons and Barrow is derived for the case of the DBI action. The
resulting slow roll conditions augment the standard ones valid in the case of
canonical kinetic terms. It is also shown that in DBI models inflation does not
require that the potential dominate the energy density.Comment: References adde
Cloud computing based bushfire prediction for cyber-physical emergency applications
In the past few years, several studies proposed to reduce the impact of bushfires by mapping their occurrences and spread. Most of these prediction/mapping tools and models were designed to run either on a single local machine or a High performance cluster, neither of which can scale with users' needs. The process of installing these tools and models their configuration can itself be a tedious and time consuming process. Thus making them, not suitable for time constraint cyber-physical emergency systems. In this research, to improve the efficiency of the fire prediction process and make this service available to several users in a scalable and cost-effective manner, we propose a scalable Cloud based bushfire prediction framework, which allows forecasting of the probability of fire occurrences in different regions of interest. The framework automates the process of selecting particular bushfire models for specific regions and scheduling users' requests within their specified deadlines. The evaluation results show that our Cloud based bushfire prediction system can scale resources and meet user requirements. © 2017 Elsevier B.V
On Power Law Inflation in DBI Models
Inflationary models in string theory which identify the inflaton with an open
string modulus lead to effective field theories with non-canonical kinetic
terms: Dirac-Born-Infeld scalar field theories. In the case of a -brane
moving in an AdS throat with a quadratic scalar field potential DBI kinetic
terms allow a novel realization of power law inflation. This note adresses the
question of whether this behaviour is special to this particular choice of
throat geometry and potential. The answer is that for any throat geometry one
can explicitly find a potential which leads to power law inflation. This
generalizes the well known fact that an exponential potential gives power law
inflation in the case of canonical kinetic terms.Comment: References and comments adde
Brane Bremsstrahlung in DBI Inflation
We consider the effect of trapped branes on the evolution of a test brane
whose motion generates DBI inflation along a warped throat. The coupling
between the inflationary brane and a trapped brane leads to the radiation of
non-thermal particles on the trapped brane. We calculate the Gaussian spectrum
of the radiated particles and their backreaction on the DBI motion of the
inflationary brane. Radiation occurs for momenta lower than the speed of the
test brane when crossing the trapped brane. The slowing down effect is either
due to a parametric resonance when the interaction time is small compared to
the Hubble time or a tachyonic resonance when the interaction time is large. In
both cases the motion of the inflationary brane after the interaction is
governed by a chameleonic potential,which tends to slow it down. We find that a
single trapped brane can hardly slow down a DBI inflaton whose fluctuations
lead to the Cosmic Microwave Background spectrum. A more drastic effect is
obtained when the DBI brane encounters a tightly spaced stack of trapped
branes.Comment: 20 pages, 1 figur
Universality in D-brane Inflation
We study the six-field dynamics of D3-brane inflation for a general scalar
potential on the conifold, finding simple, universal behavior. We numerically
evolve the equations of motion for an ensemble of more than 7 \times 10^7
realizations, drawing the coefficients in the scalar potential from statistical
distributions whose detailed properties have demonstrably small effects on our
results. When prolonged inflation occurs, it has a characteristic form: the
D3-brane initially moves rapidly in the angular directions, spirals down to an
inflection point in the potential, and settles into single-field inflation. The
probability of N_{e} e-folds of inflation is a power law, P(N_{e}) \propto
N_{e}^{-3}, and we derive the same exponent from a simple analytical model. The
success of inflation is relatively insensitive to the initial conditions: we
find attractor behavior in the angular directions, and the D3-brane can begin
far above the inflection point without overshooting. In favorable regions of
the parameter space, models yielding 60 e-folds of expansion arise
approximately once in 10^3 trials. Realizations that are effectively
single-field and give rise to a primordial spectrum of fluctuations consistent
with WMAP, for which at least 120 e-folds are required, arise approximately
once in 10^5 trials. The emergence of robust predictions from a six-field
potential with hundreds of terms invites an analytic approach to multifield
inflation.Comment: 28 pages, 9 figure
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