1,797 research outputs found
Constraining Dark Energy with Clusters: Complementarity with Other Probes
The Figure of Merit Science Working Group (FoMSWG) recently forecast the
constraints on dark energy that will be achieved prior to the Joint Dark Energy
Mission (JDEM) by ground-based experiments that exploit baryon acoustic
oscillations, type Ia supernovae, and weak gravitational lensing. We show that
cluster counts from on-going and near-future surveys should provide robust,
complementary dark energy constraints. In particular, we find that optimally
combined optical and Sunyaev-Zel'dovich effect cluster surveys should improve
the Dark Energy Task Force (DETF) figure of merit for pre-JDEM projects by a
factor of two even without prior knowledge of the nuisance parameters in the
cluster mass-observable relation. Comparable improvements are achieved in the
forecast precision of parameters specifying the principal component description
of the dark energy equation of state parameter as well as in the growth index
gamma. These results indicate that cluster counts can play an important
complementary role in constraining dark energy and modified gravity even if the
associated systematic errors are not strongly controlled.Comment: 6 pages, 3 figures, accepted to Phys. Rev. D. Discussion section
adde
Shadows and strong gravitational lensing: a brief review
For ultra compact objects (UCOs), Light Rings (LRs) and Fundamental Photon
Orbits (FPOs) play a pivotal role in the theoretical analysis of strong
gravitational lensing effects, and of BH shadows in particular. In this short
review, specific models are considered to illustrate how FPOs can be useful in
order to understand some non-trivial gravitational lensing effects. This paper
aims at briefly overviewing the theoretical foundations of these effects,
touching also some of the related phenomenology, both in General Relativity
(GR) and alternative theories of gravity, hopefully providing some intuition
and new insights for the underlying physics, which might be critical when
testing the Kerr black hole hypothesis.Comment: 32 pages, 9 figures; Review paper in the General Relativity and
Gravitation (GRG) Topical Collection "Testing the Kerr spacetime with
gravitational-wave and electromagnetic observations" (Guest Editor: Emanuele
Berti); v2: Typo corrected and two references adde
Multi-Device Nutrition Control
Precision nutrition is a popular eHealth topic among several groups, such as athletes, 1
people with dementia, rare diseases, diabetes, and overweight. Its implementation demands tight 2
nutrition control, starting with nutritionists who build up food plans for specific groups or individuals. 3
Each person then follows the food plan by preparing meals and logging all food and water intake. 4
However, the discipline demanded to follow food plans and log food intake turns out into high 5
dropout rates. This article presents the concepts, requirements, and architecture of a solution that 6
assists the nutritionist in building up and revising food plans and the user following them. It does 7
so by minimizing human-computer interaction by integrating the nutritionist and user systems 8
and introducing off-the-shelf IoT devices in the system, such as temperature sensors, smartwatches, 9
smartphones, and smart bottles. An interaction time analysis using the Keystroke Level Model 10
provides a baseline for comparison in future work addressing both the use of machine learning and 11
IoT devices to reduce the interaction effort of users.info:eu-repo/semantics/publishedVersio
Assessing the quality of the relation between scalarizing function parameters and solutions in multiobjective optimization
Different Multi-Objective Optimization Methods
(MOOM) for solving Multi-Objective Optimization Problems
(MOOP) have been suggested in the literature. These methods
often comprise two stages (not necessarily sequential): i) the
search for the Pareto-optimal set and ii) the selection of a single
solution from this non-dominated set. Various studies
comparing performance of particular aspects of these methods
have been carried out. However, a theoretical support that
changes on the preferences of a Decision Maker (DM) will be
reflected in the same way on the solution of the MOOP given by
the MOOM has not been presented. In this work a consistency
measure to assess MOOM is proposed. It will used to compare
the performance of different methods available in the
literature. This study was performed using some benchmark
test problems, with two criteria.This work was supported in part by the Portuguese Fundacao para a Ciencia e Tecnologia under grants: PTDC/GES/70168/2006 and SFRH/BD/22808/2005
Aspect oriented pluggable support for parallel computing
In this paper, we present an approach to develop parallel applications based on aspect oriented programming. We propose a collection of aspects to implement group communication mechanisms on parallel applications. In our approach, parallelisation code is developed by composing the collection into the application core functionality. The approach requires fewer changes to sequential applications to parallelise the core functionality than current alternatives and yields more modular code. The paper presents the collection and shows how the aspects can be used to develop efficient parallel applicationsFundação para a Ciência e a Tecnologia (FCT) - PPC-VM (Portable Parallel Computing based on Virtual Machines) Project POSI/CHS/47158/2002; SOFTAS (POSI/EIA/60189/2004).Fundo Europeu de Desenvolvimento Regional (FEDER)
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