144,280 research outputs found
A Soft Computing Approach to Dynamic Load Balancing in 3GPP LTE
A major objective of the 3GPP LTE standard is the provision of high-speed data services. These services must be guaranteed under varying radio propagation conditions, to stochastically distributed mobile users. A necessity for determining and regulating the traffic load of eNodeBs naturally ensues. Load balancing is a self-optimization operation of self-organizing networks (SON). It aims at ensuring an equitable distribution of users in the network. This translates into better user satisfaction and a more efficient use of network resources. Several methods for load balancing have been proposed. Most of the algorithms are based on hard (traditional) computing which does not utilize the tolerance for precision of load balancing. This paper proposes the use of soft computing, precisely adaptive Neuro-fuzzy inference system (ANFIS) model for dynamic QoS aware load balancing in 3GPP LTE. The use of ANFIS offers learning capability of neural network and knowledge representation of fuzzy logic for a load balancing solution that is cost effective and closer to human intuitio
Multi-Thread Hydrodynamic Modeling of a Solar Flare
Past hydrodynamic simulations have been able to reproduce the high
temperatures and densities characteristic of solar flares. These simulations,
however, have not been able to account for the slow decay of the observed flare
emission or the absence of blueshifts in high spectral resolution line
profiles. Recent work has suggested that modeling a flare as an sequence of
independently heated threads instead of as a single loop may resolve the
discrepancies between the simulations and observations. In this paper we
present a method for computing multi-thread, time-dependent hydrodynamic
simulations of solar flares and apply it to observations of the Masuda flare of
1992 January 13. We show that it is possible to reproduce the temporal
evolution of high temperature thermal flare plasma observed with the
instruments on the \textit{GOES} and \textit{Yohkoh} satellites. The results
from these simulations suggest that the heating time-scale for a individual
thread is on the order of 200 s. Significantly shorter heating time scales (20
s) lead to very high temperatures and are inconsistent with the emission
observed by \textit{Yohkoh}.Comment: Submitted to Ap
Career Transitions and Trajectories: A Case Study in Computing
From artificial intelligence to network security to hardware design, it is
well-known that computing research drives many important technological and
societal advancements. However, less is known about the long-term career paths
of the people behind these innovations. What do their careers reveal about the
evolution of computing research? Which institutions were and are the most
important in this field, and for what reasons? Can insights into computing
career trajectories help predict employer retention?
In this paper we analyze several decades of post-PhD computing careers using
a large new dataset rich with professional information, and propose a versatile
career network model, R^3, that captures temporal career dynamics. With R^3 we
track important organizations in computing research history, analyze career
movement between industry, academia, and government, and build a powerful
predictive model for individual career transitions. Our study, the first of its
kind, is a starting point for understanding computing research careers, and may
inform employer recruitment and retention mechanisms at a time when the demand
for specialized computational expertise far exceeds supply.Comment: To appear in KDD 201
Kahler Potentials of Chiral Matter Fields for Calabi-Yau String Compactifications
The Kahler potential is the least understood part of effective N=1
supersymmetric theories derived from string compactifications. Even at
tree-level, the Kahler potential for the physical matter fields, as a function
of the moduli fields, is unknown for generic Calabi-Yau compactifications and
has only been computed for simple toroidal orientifolds. In this paper we
describe how the modular dependence of matter metrics may be extracted in a
perturbative expansion in the Kahler moduli. Scaling arguments, locality and
knowledge of the structure of the physical Yukawa couplings are sufficient to
find the relevant Kahler potential. Using these techniques we compute the
`modular weights' for bifundamental matter on wrapped D7 branes for
large-volume IIB Calabi-Yau flux compactifications. We also apply our
techniques to the case of toroidal compactifications, obtaining results
consistent with those present in the literature. Our techniques do not provide
the complex structure moduli dependence of the Kahler potential, but are
sufficient to extract relevant information about the canonically normalised
matter fields and the soft supersymmetry breaking terms in gravity mediated
scenarios.Comment: JHEP style, 24 pages, 4 figures. v2: New section and reference adde
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