Mechanical characterization of adobe bricks in existing constructions in Aveiro Region, Portugal

In Portugal it is common to find earth constructions all over the country, being predominant in the centre and south. In the past, earth was massified as a construction material, used with different typologies and applications. Adobe construction is confined mainly to the central part of the country and more viewed in the west coast (gandaresa region). Aveiro, an Atlantic sea line city is an excellent example of a place with several ancient adobe constructions, some with architectural and historical relevance like some art-noveau houses. Just a few ones have been preserved with the passing years. The majority are in the threshold of ruin and structurally weak needing an urgent solution for their furtherance as buildings. Preservation and rehabilitation of those constructions was simply forgotten, carrying to the actual situation. In this context, becomes urgent, and absolutely necessary, to advance with rehabilitation and strengthening of these constructions. A great difficulty for technicians working on the rehabilitation relies on the lack of knowledge on adobe’s mechanical behaviour. In fact, in order to properly describe the structural behaviour of those constructions, there’s a need to investigate the mechanical properties of adobe. Hence, this paper presents a study which intended to characterise the behaviour of adobe brick units. Specimens were prepared from selected representative Aveiro’s constructions. The prepared specimens were tested in order to evaluate their mechanical behaviour in compression and tension. Usually, adobe blocks were made from clay soils. A basic characterization was also performed by the adobes’ granulometric analysis

Synchronisation Induced by Repulsive Interactions in a System of van der Pol Oscillators

We consider a system of identical van der Pol oscillators, globally coupled through their velocities, and study how the presence of competitive interactions affects its synchronisation properties. We will address the question from two points of view. Firstly, we will investigate the role of competitive interactions on the synchronisation among identical oscillators. Then, we will show that the presence of an intermediate fraction of repulsive links results in the appearance of macroscopic oscillations at that signal's rhythm, in regions where the individual oscillator is unable to synchronise with a weak external signal

Parsing as Reduction

We reduce phrase-representation parsing to dependency parsing. Our reduction is grounded on a new intermediate representation, "head-ordered dependency trees", shown to be isomorphic to constituent trees. By encoding order information in the dependency labels, we show that any off-the-shelf, trainable dependency parser can be used to produce constituents. When this parser is non-projective, we can perform discontinuous parsing in a very natural manner. Despite the simplicity of our approach, experiments show that the resulting parsers are on par with strong baselines, such as the Berkeley parser for English and the best single system in the SPMRL-2014 shared task. Results are particularly striking for discontinuous parsing of German, where we surpass the current state of the art by a wide margin

Types for X10 Clocks

X10 is a modern language built from the ground up to handle future parallel systems, from multicore machines to cluster configurations. We take a closer look at a pair of synchronisation mechanisms: finish and clocks. The former waits for the termination of parallel computations, the latter allow multiple concurrent activities to wait for each other at certain points in time. In order to better understand these concepts we study a type system for a stripped down version of X10. The main result assures that well typed programs do not run into the errors identified in the X10 language reference, namely the ClockUseException. The study will open, we hope, doors to a more flexible utilisation of clocks in the X10 language.Comment: In Proceedings PLACES 2010, arXiv:1110.385

Divide and conquer: resonance induced by competitive interactions

We study an Ising model in a network with disorder induced by the presence of both attractive and repulsive links. This system is subjected to a subthreshold signal, and the goal is to see how the response is enhanced for a given fraction of repulsive links. This can model a network of spin-like neurons with excitatory and inhibitory couplings. By means of numerical simulations and analytical calculations we find that there is an optimal probability, such that the coherent response is maximal

The effects of k-dependent self-energy in the electronic structure of correlated materials

It is known from self-energy calculations in the electron gas and sp materials based on the GW approximation that a typical quasiparticle renormalization factor (Z factor) is approximately 0.7-0.8. Band narrowing in electron gas at rs = 4 due to correlation effects, however, is only approximately 10%, significantly smaller than the Z factor would suggest. The band narrowing is determined by the frequency-dependent self-energy, giving the Z factor, and the momentum-dependent or nonlocal self-energy. The results for the electron gas point to a strong cancellation between the effects of frequency- and momentum-dependent self-energy. It is often assumed that for systems with a nar- row band the self-energy is local. In this work we show that even for narrow-band materials, such as SrVO3, the nonlocal self-energy is important.Comment: 7 pages, 6 figure

Selective Attention for Context-aware Neural Machine Translation

Despite the progress made in sentence-level NMT, current systems still fall short at achieving fluent, good quality translation for a full document. Recent works in context-aware NMT consider only a few previous sentences as context and may not scale to entire documents. To this end, we propose a novel and scalable top-down approach to hierarchical attention for context-aware NMT which uses sparse attention to selectively focus on relevant sentences in the document context and then attends to key words in those sentences. We also propose single-level attention approaches based on sentence or word-level information in the context. The document-level context representation, produced from these attention modules, is integrated into the encoder or decoder of the Transformer model depending on whether we use monolingual or bilingual context. Our experiments and evaluation on English-German datasets in different document MT settings show that our selective attention approach not only significantly outperforms context-agnostic baselines but also surpasses context-aware baselines in most cases.Comment: Accepted at NAACL-HLT 201