How Important is Syntactic Parsing Accuracy? An Empirical Evaluation on Rule-Based Sentiment Analysis

Syntactic parsing, the process of obtaining the internal structure of sentences in natural languages, is a crucial task for artificial intelligence applications that need to extract meaning from natural language text or speech. Sentiment analysis is one example of application for which parsing has recently proven useful. In recent years, there have been significant advances in the accuracy of parsing algorithms. In this article, we perform an empirical, task-oriented evaluation to determine how parsing accuracy influences the performance of a state-of-the-art rule-based sentiment analysis system that determines the polarity of sentences from their parse trees. In particular, we evaluate the system using four well-known dependency parsers, including both current models with state-of-the-art accuracy and more innacurate models which, however, require less computational resources. The experiments show that all of the parsers produce similarly good results in the sentiment analysis task, without their accuracy having any relevant influence on the results. Since parsing is currently a task with a relatively high computational cost that varies strongly between algorithms, this suggests that sentiment analysis researchers and users should prioritize speed over accuracy when choosing a parser; and parsing researchers should investigate models that improve speed further, even at some cost to accuracy.Comment: 19 pages. Accepted for publication in Artificial Intelligence Review. This update only adds the DOI link to comply with journal's term

System-Level Design of Energy-Proportional Many-Core Servers for Exascale Computing

Continuous advances in manufacturing technologies are enabling the development of more powerful and compact high-performance computing (HPC) servers made of many-core processing architectures. However, this soaring demand for computing power in the last years has grown faster than emiconductor technology evolution can sustain, and has produced as collateral undesirable effect a surge in power consumption and heat density in these new HPC servers, which result on significant performance degradation. In this keynote, I advocate to completely revise the current HPC server architectures. In particular, inspired by the mammalian brain, I propose to design a disruptive three-dimensional (3D) computing server architecture that overcomes the prevailing worst-case power and cooling provisioning paradigm for servers. This new 3D server design champions a new system-level thermal modeling, which can be used by novel proactive energy controllers for detailed heat and energy management in many-core HPC servers, thanks to micro-scale liquid cooling. Then, I will show the impact of new near-threshold computing architectures on server design, and how we can integrate new on-chip microfluidic fuel cell networks to enable energy-scalability in future generations of many-core HPC servers targeting Exascale computing.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech

Cartesian Humility and Pyrrhonian Passivity: The Ethical Significance of Epistemic Agency

While the Academic sceptics followed the plausible as a criterion of truth and guided their practice by a doxastic norm, so thinking that agential performances are actions for which the agent assumes responsibility, the Pyrrhonists did not accept rational belief-management, dispensing with judgment in empirical matters. In this sense, the Pyrrhonian Sceptic described himself as not acting in any robust sense of the notion, or as ‘acting’ out of sub-personal and social mechanisms. The important point is that the Pyrrhonian advocacy of a minimal conception of ‘belief’ was motivated by ethical concerns: avoiding any sort of commitment, he attempted to preserve his peace of mind. In this article, I argue for a Cartesian model of rational guidance that, in line with some current versions of an agential virtue epistemology, does involve judgment and risk, and thus which is true both to our rational constitution and to our finite and fallible nature. Insofar as epistemic humility is a virtue of rational agents that recognise the limits of their judgments, Pyrrhonian scepticism, and a fortiori any variety of naturalism, is unable to accommodate this virtue. This means that, in contrast to the Cartesian model, the Pyrrhonist does not provide a satisfactory answer to the problem of cognitive disintegration. The Pyrrhonist thus becomes a social rebel, one that violates the norm of serious personal assent that enables the flourishing of a collaborative and social species which depends on agents that, however fallible, are accountable for their actions and judgments

A mid-infrared exploration of the dusty environments of active galactic nuclei

We present the first results from a mid-infrared survey of local Active Galactic Nuclei (AGN) using the CanariCam (CC) instrument on the 10.4m Gran Telescopio Canarias (GTC). We are obtaining sub-arcsecond angular resolution (0.3-0.6 arcsec) mid-IR imaging and spectroscopic observations of a sample of 100 local AGN, which are complemented with data taken with T-ReCS, VISIR, and Michelle. The full sample contains approximately 140 AGN, covers nearly six orders of magnitude in AGN luminosity, and includes low-luminosity AGN (LLAGN), Seyfert 1s and 2s, QSO, radio galaxies, and (U)LIRGs. The main goals of this project are: (1) to test whether the properties of the dusty tori of the AGN Unified Model depend on the AGN type, (2) to study the nuclear star formation activity and obscuration of local AGN, and (3) to explore the role of the dusty torus in LLAGN.Comment: Conference proceedings of IAU Symposium 304: Multiwavelength AGN surveys and studie

Nature of the spin-glass phase in dense packings of Ising dipoles with random anisotropy axes

By Monte Carlo simulations, we study the character of the spinglass (SG) phase in dense disordered packings of magnetic nanoparticles (NPs). We focus on NPs which have large uniaxial anisotropies and can be well represented as Ising dipoles. Dipoles are placed on SC lattices and point along randomly oriented axes. From the behaviour of a SG correlation length we determine the transition temperature Tc between the paramagnetic and a SG phase. For temperatures well below Tc we find distributions of the SG overlap parameter q that are strongly sample-dependent and exhibit several spikes. We find that the average width of spikes, and the fraction of samples with spikes higher than a certain threshold does not vary appreciably with the system sizes studied. We compare these results with the ones found previously for 3D site-diluted systems of parallel Ising dipoles and with the behaviour of the Sherrington-Kirkpatrick model.We thank financial support from MINECO FIS2013-43201-P Gran