8,566 research outputs found
The size function of quadratic extensions of complex quadratic fields
The function for a number field is an analogue of the dimension of the
Riemann-Roch spaces of divisors on an algebraic curve. In this paper, we prove
the conjecture of van der Geer and Schoof about the maximality of at the
trivial Arakelov divisor for quadratic extensions of complex quadratic fields
Computing dimensions of spaces of Arakelov divisors of number fields
The function for a number field is analogous to the dimension of the
Riemann-Roch spaces at divisors on an algebraic curve. We provide a method to
compute this function for number fields with unit group of rank at most 2, even
with large discriminant. This method is based on using LLL-reduced bases, the
"jump algorithm" and Poisson summation formula
Reduced ideals from the reduction algorithm
The reduction algorithm is used to compute reduced ideals of a number field.
However, there are reduced ideals that can never be obtained from this
algorithm. In this paper, we will show that these ideals have inverses of
larger norms among reduced ones. Especially, we represent a sufficient and
necessary condition for reduced ideals of real quadratic fields to be obtained
from the reduction algorithm
RF Wireless Power Transfer: Regreening Future Networks
Green radio communication is an emerging topic since the overall footprint of
information and communication technology (ICT) services is predicted to triple
between 2007 and 2020. Given this research line, energy harvesting (EH) and
wireless power transfer (WPT) networks can be evaluated as promising
approaches. In this paper, an overview of recent trends for future green
networks on the platforms of EH and WPT is provided. By rethinking the
application of radio frequency (RF)-WPT, a new concept, namely green RF-WTP, is
introduced. Accordingly, opening challenges and promising combinations among
current technologies, such as small-cell, millimeter (mm)-wave, and Internet of
Things (IoT) networks, are discussed in details to seek solutions for the
question with how to re-green the future networks?Comment: 6 pages, 5 figure
XACs-DyPol: Towards an XACML-based Access Control Model for Dynamic Security Policy
Authorization and access control play an essential role in protecting
sensitive information from malicious users. The system is based on security
policies to determine if an access request is allowed. However, of late, the
growing popularity of big data has created a new challenge which the security
policy management is facing with such as dynamic and update policies in run
time. Applications of dynamic policies have brought many benefits to modern
domains. To the best of our knowledge, there are no previous studies focusing
on solving authorization problems in the dynamic policy environments. In this
article, we focus on analyzing and classifying when an update policy occurs,
and provide a pragmatic solution for such dynamic policies. The contribution of
this work is twofold: a novel solution for managing the policy changes even
when the access request has been granted, and an XACML-based implementation to
empirically evaluate the proposed solution. The experimental results show the
comparison between the newly introduced XACs-DyPol framework with Balana (an
open source framework supporting XACML 3.0). The datasets are XACML 3.0-based
policies, including three samples of real-world policy sets. According to the
comparison results, our XACs-DyPol framework performs better than Balana in
terms of all updates in dynamic security policy cases. Specially, our proposed
solution outperforms by an order of magnitude when the policy structure
includes complex policy sets, policies, and rules or some complicated
comparison expression which contains higher than function and less than
function.Comment: 12 page
Downlink Power Optimization for Heterogeneous Networks with Time Reversal-based Transmission under Backhaul Limitation
In this paper, we investigate an application of two different beamforming
techniques and propose a novel downlink power minimization scheme for a
two-tier heterogeneous network (HetNet) model. In this context, we employ time
reversal (TR) technique to a femtocell base station (FBS) whereas we assume
that a macrocell base station (MBS) uses a zero-forcing-based algorithm and the
communication channels are subject to frequency selective fading. Additionally,
HetNet's backhaul connection is unable to support a sufficient throughput for
signaling information exchange between two tiers. Given the considered HetNet
model, a downlink power minimization scheme is proposed, and closed-form
expressions concerning the optimal solution are provided, taking this
constraint into account. Furthermore, considering imperfect channel estimation
at TR-employed femtocell, a worst-case robust power minimization problem is
formulated. By devising TR worst-case analysis, this robust problem is
transformed into an equivalent formulation that is tractable to solve. The
results presented in our paper show that the TR technique outperforms the
zero-forcing one in the perspective of beamforming methods for femtocell
working environments. Finally, we validate the proposed power loading strategy
for both cases of perfect and imperfect channel estimations.Comment: 15 pages, 8 figure
Boundary regularity of the solution to the Complex Monge-Amp\`{e}re equation on pseudoconvex domains of infinite type
Let be a bounded, pseudoconvex domain of satisfying
the "-Property". The -Property is a consequence of the geometric "type"
of the boundary; it holds for all pseudoconvex domains of finite type but may
also occur for many relevant classes of domains of infinite type. In this
paper, we prove the existence, uniqueness and "weak" H\"older-regularity up to
the boundary of the solution to the Dirichlet problem for the complex
Monge-Amp\`{e}re equation Comment: 15 page
On the volume and the number of lattice of some semialgebraic sets
Let be a polynomial map;
. We show that if
satisfies the Mikhailov - Gindikin condition then \begin{itemize} \item[(i)]
\item[(ii)]
, as , \end{itemize} where the exponents $\theta,\ k,\
\theta',\ k'f$. \\ \indent Moreover, the polynomial maps satisfy the Mikhailov - Gindikin
condition form an open subset of the set of polynomial maps having the same
Newton polyhedron
An explicit estimate on multiplicity truncation in the second main theorem for holomorphic curves encountering hypersurfaces in general position in projective space
Yan and Chen proved a weak Cartan-type second main theorem for holomorphic
curves meeting hypersurfaces in projective space that included truncated
counting functions. Here we give an explicit estimate for the level of
truncation
ICE: A General and Validated Energy Complexity Model for Multithreaded Algorithms
Like time complexity models that have significantly contributed to the
analysis and development of fast algorithms, energy complexity models for
parallel algorithms are desired as crucial means to develop energy efficient
algorithms for ubiquitous multicore platforms. Ideal energy complexity models
should be validated on real multicore platforms and applicable to a wide range
of parallel algorithms. However, existing energy complexity models for parallel
algorithms are either theoretical without model validation or
algorithm-specific without ability to analyze energy complexity for a
wide-range of parallel algorithms.
This paper presents a new general validated energy complexity model for
parallel (multithreaded) algorithms. The new model abstracts away possible
multicore platforms by their static and dynamic energy of computational
operations and data access, and derives the energy complexity of a given
algorithm from its work, span and I/O complexity. The new model is validated by
different sparse matrix vector multiplication (SpMV) algorithms and dense
matrix multiplication (matmul) algorithms running on high performance computing
(HPC) platforms (e.g., Intel Xeon and Xeon Phi). The new energy complexity
model is able to characterize and compare the energy consumption of SpMV and
matmul kernels according to three aspects: different algorithms, different
input matrix types and different platforms. The prediction of the new model
regarding which algorithm consumes more energy with different inputs on
different platforms, is confirmed by the experimental results. In order to
improve the usability and accuracy of the new model for a wide range of
platforms, the platform parameters of ICE model are provided for eleven
platforms including HPC, accelerator and embedded platforms.Comment: 23 pages, 8 figures, 33 reference
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