2,911 research outputs found
Inferring Energy Bounds via Static Program Analysis and Evolutionary Modeling of Basic Blocks
The ever increasing number and complexity of energy-bound devices (such as
the ones used in Internet of Things applications, smart phones, and mission
critical systems) pose an important challenge on techniques to optimize their
energy consumption and to verify that they will perform their function within
the available energy budget. In this work we address this challenge from the
software point of view and propose a novel parametric approach to estimating
tight bounds on the energy consumed by program executions that are practical
for their application to energy verification and optimization. Our approach
divides a program into basic (branchless) blocks and estimates the maximal and
minimal energy consumption for each block using an evolutionary algorithm. Then
it combines the obtained values according to the program control flow, using
static analysis, to infer functions that give both upper and lower bounds on
the energy consumption of the whole program and its procedures as functions on
input data sizes. We have tested our approach on (C-like) embedded programs
running on the XMOS hardware platform. However, our method is general enough to
be applied to other microprocessor architectures and programming languages. The
bounds obtained by our prototype implementation can be tight while remaining on
the safe side of budgets in practice, as shown by our experimental evaluation.Comment: Pre-proceedings paper presented at the 27th International Symposium
on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur,
Belgium, 10-12 October 2017 (arXiv:1708.07854). Improved version of the one
presented at the HIP3ES 2016 workshop (v1): more experimental results (added
benchmark to Table 1, added figure for new benchmark, added Table 3),
improved Fig. 1, added Fig.
Transition period between vegetation growth and senescence controls interannual variability of C fluxes in a Mediterranean reed wetland
Wetlands are crucial ecosystems modulating climate change due to their great potential
to capture carbon dioxide (CO2), emit methane (CH4) and regulate local climate through
evapotranspiration (ET). Common reed wetlands are particularly interesting given their
high productivity, abundance and highly efficient internal gas-transport mechanism.
However, little is known about the interannual behavior and dominant controlling
factors of Mediterranean reed wetlands, characterized by seasonal flooding and
remarkable weather variability. After 6 years of ecosystem carbon and ET flux
measurements by eddy covariance (3 years for CH4 fluxes), this study shows the
functional vulnerability of such wetlands to climate variability, switching between
carbon (CO2+CH4) sink (660 g CO2-eeq m-2
y
-1
, in 2014) and source (360 g CO2-eq m-2
y
-1
, in 2016) in short periods of time. According to our analyses, the great interannual
variability appeared to mainly depend on the behavior of reed growth dynamics during
the transition to senescence period, what is confirmed through the Enhanced Vegetation
Index as a proxy of photosynthetic activity. Additionally, a similar behavior of seasonal
and daily patterns of carbon fluxes and ET was found compared with other wetlands
under different climates
Optimized design of local shielding for the IFMIF/EVEDA beam dump
This paper describes the local shielding design process of the IFMIF/EVEDA Beam Dump and the most relevant results obtained from the simulations. Different geometries and materials have been considered, and the design has been optimized taking into account the origin of the doses, the effect of the walls of the accelerator vault and the space restrictions. The initial idea was to shield the beam stopper with a large water tank of easy transport and dismantling but it was shown to be insufficient to satisfy the dose limit requirements, basically due to photon dose, and hence a denser shield combining hydrogenous and heavy materials was preferred. It will be shown that, with this new shielding, dose rate outside the accelerator vault during operation comply with the legal limits and unrestricted maintenance operations inside most of the vault are possible after a reasonable cooling time after shutdown
Break-informed audio decomposition for interactive redrumming
Redrumming or drum replacement is used to substitute or enhance the drum hits in a song with one-shot drum sounds obtained from an external collection or database. In an ideal setting, this is done on multitrack audio, where one or more tracks are dedicated exclusively to drums and percussion. However, most non-professional producers and DJs only have access to mono or stereo downmixes of the music they work with. Motivated by this scenario, as well
as previous work on decomposition techniques for audio signals, we propose a step towards enabling full-fledged redrumming with mono downmixes
Macro and micromechanics analysis of short fiber composites stiffness: The case of old newspaper fibers-polypropylene composites
Stiffness is one of the most relevant characteristics of composite materials. Natural wood fibers have demonstrated their ability to increase the Young's moduli of composite materials, and old newspapers are a potential source of reinforcing fibers for composite materials. There are some micromechanic models to predict the Young's modulus of composite materials, and one of the input data is the intrinsic modulus of their fibers. This intrinsic modulus is a value which is difficult or impossible to measure in the case of wood fibers, due to their measures. This paper evaluates the stiffening abilities of old newspaper fibers and the possibility to back calculate the value of the intrinsic Young's Modulus by means of micromechanic models. Different percentages of old newspaper fibers were compounded with polypropylene (PP). Micromechanics of the fibers were obtained using Hirsch model, Cox-Krenchel's model, Tsai-Pagano model and Halpin-Tsai equations. The most important
results were the average intrinsic Young's modulus of the fibers, the mean orientation angle and the mean modulus efficiency factor.Serrano, A.; Espinach, FX.; Tresserras, J.; Rey Tormos, RMD.; Pellicer, N.; Mutje Pujol, P. (2014). Macro and micromechanics analysis of short fiber composites stiffness: The case of old newspaper fibers-polypropylene composites. Materials and Design. 55:319-324. doi:10.1016/j.matdes.2013.10.011S3193245
The impact of health status and human capital formation on regional performance: Empirical evidence
The purpose of this paper is to analyze the impact of health on growth, assuming that it is a fundamental component of the human capital of a region along with education. Various measures of population health status are used, together with a health index generated by Principal Component Analysis. Potential endogeneity between health and growth is controlled for using instrumental variable regressions and dynamic panel data. The results show a positive effect of a change in health status on regional output and a negative effect of proxy variables for health limitations on regional performance. This corroborates the importance of investing in health along with education with the aim of improving not only the well-being of individuals but the human capital and growth of a region
Stabilities of nanohydrated thymine radical cations: insights from multiphoton ionization experiments and ab initio calculations
Multi-photon ionization experiments have been carried out on thymine-water clusters in the gas phase. Metastable H2O loss from T+(H2O)n was observed at n ≥ 3 only. Ab initio quantum-chemical calculations of a large range of optimized T+(H2O)n conformers have been performed up to n = 4, enabling binding energies of water to be derived. These decrease smoothly with n, consistent with the general trend of increasing metastable H2O loss in the experimental data. The lowest-energy conformers of T+(H2O)3 and T+(H2O)4 feature intermolecular bonding via charge-dipole interactions, in contrast with the purely hydrogen-bonded neutrals. We found no evidence for a closed hydration shell at n = 4, also contrasting with studies of neutral clusters
Extreme Starbursts in the Local Universe
The "Extreme starbursts in the local universe" workshop was held at the
Insituto de Astrofisica de Andalucia in Granada, Spain on 21-25 June 2010.
Bearing in mind the advent of a new generation of facilities such as JWST,
Herschel, ALMA, eVLA and eMerlin, the aim of the workshop was to bring together
observers and theorists to review the latest results. The purpose of the
workshop was to address the following issues: what are the main modes of
triggering extreme starbursts in the local Universe? How efficiently are stars
formed in extreme starbursts? What are the star formation histories of local
starburst galaxies? How well do the theoretical simulations model the
observations? What can we learn about starbursts in the distant Universe
through studies of their local counterparts? How important is the role of
extreme starbursts in the hierarchical assembly of galaxies? How are extreme
starbursts related to the triggering of AGN in the nuclei of galaxies? Overall,
41 talks and 4 posters with their corresponding 10 minutes short talks were
presented during the workshop. In addition, the workshop was designed with
emphasis on discussions, and therefore, there were 6 discussion sessions of up
to one hour during the workshop. Here is presented a summary of the purposes of
the workshop as well as a compilation of the abstracts corresponding to each of
the presentations. The summary and conclusions of the workshop along with a
description of the future prospects by Sylvain Veilleux can be found in the
last section of this document. A photo of the assistants is included.Comment: worksho
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